Downlink transmission method performed by user equipment and user equipment

Abstract

A downlink transmission method and a user equipment executed by a user equipment are provided. The downlink transmission method executed by the user equipment comprises: receiving a predefined downlink signal in a predefined downlink resource, and performing ACK feedback according to the received downlink signal, thereby realizing downlink data transmission in an RRC idle or inactive state, or establishing an RRC connection faster.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communication technology, and more specifically, to a method and device for receiving downlink data in an idle or inactive state of Radio Resource Control (RRC). Background Art

[0002] For machine communication (MTC) user equipment (UE) and narrowband Internet of Things (NB-IOT) UE, due to the limitation of application scenarios, the battery life is required to be high. When designing the system, UE power consumption has always been a key improvement indicator, and relevant standards are also evolving based on the goal of reducing UE power consumption. In the existing 5G system, UE must support uplink or downlink data transmission in the RRC connection state. This is relatively inefficient for MTC or IoT (also known as NR-light) devices. For the characteristics of IoT sparse small data packets, the signaling interaction between the terminal and the network can be simplified, for example, data is sent without establishing a radio resource control (RRC) connection state. This can greatly simplify signaling and save power consumption. How to perform uplink / downlink data transmission in the RRC idle or inactive state will become an important research direction. In addition, how to quickly perform random access procedures can also simplify signaling and save power consumption, which is also an important research direction. Summary of the invention

[0003] An exemplary embodiment of the present disclosure is to provide a downlink transmission method performed by a user equipment and the user equipment, so as to perform downlink data transmission in an RRC connected state or an RRC idle or inactive state.

[0004] According to an exemplary embodiment of the present disclosure, a downlink transmission method performed by a user equipment is provided, comprising: receiving a predefined downlink signal in a predefined downlink resource; and performing ACK feedback according to the received downlink signal.

[0005] Optionally, the predefined downlink signal is a second type PDSCH, and the step of performing ACK feedback according to the received downlink signal may include: demodulating the second type PDSCH, and performing ACK feedback according to the demodulation result.

[0006] Optionally, the downlink transmission method may further include: entering a sleep state when a predefined sleep condition is met.

[0007] Optionally, the predefined downlink resource may be a predefined second type PDSCH resource.

[0008] Optionally, the predefined second-type PDSCH resources are downlink resources of a RAR PDSCH determined according to a random access response RAR PDCCH.

[0009] Optionally, the predefined downlink resource may be a first search space, and the first search space is a paging search space used for monitoring a PDCCH that schedules a first type of PDSCH.

[0010] Optionally, the predefined downlink resource may be a third search space, which is a search space used to monitor the PDCCH that schedules the second type of PDSCH and to support reception of the PDCCH for downlink transmission by the user equipment in an RRC idle / deactivated state.

[0011] Optionally, when the predefined downlink resource is a third search space, the step of receiving a predefined downlink signal in the predefined downlink resource may include: receiving a predefined PDCCH in the third search space; and receiving a second type of PDSCH according to the PDCCH received in the third search space.

[0012] Optionally, when the predefined downlink resource is the first search space, the step of receiving a predefined downlink signal in the predefined downlink resource may include: receiving a predefined PDCCH in the first search space; receiving a first type of PDSCH based on the PDCCH received in the first search space; and receiving a second type of PDSCH.

[0013] Optionally, the step of receiving the second type of PDSCH may include: receiving a PDCCH in a second search space; and receiving the second type of PDSCH according to the PDCCH received in the second search space.

[0014] Optionally, before receiving the PDCCH in the second search space, the downlink transmission method may further include: sending a PRACH according to the first type of PDSCH.

[0015] Optionally, when the predefined downlink resource is a first search space, the step of receiving a predefined downlink signal in the predefined downlink resource may include: receiving a predefined PDCCH in the first search space; receiving a first type of PDSCH based on the PDCCH received in the first search space; sending PRACH based on the first type of PDSCH; monitoring PDCCH in a predefined second search space within a predetermined time window; when PDCCH is monitored within the predetermined time window, receiving PDCCH in the second search space; when the PDCCH received in the second search space indicates reception of a second type of PDSCH, receiving the second type of PDSCH.

[0016] Optionally, the step of entering the sleep state may include: entering the sleep state when a PDCCH received in the second search space indicates entering the sleep state.

[0017] Optionally, the step of entering the sleep state may include: entering the sleep state when the PDCCH is not monitored within a predetermined time window.

[0018] Optionally, the first type PDSCH may include downlink data, and / or the first type PDSCH may include at least one of the following information: PRACH resource information, second type PDSCH resource information, ACK resource information, transmission mode information, first type RNTI, and second search space resource information.

[0019] And / or, after receiving the first type of PDSCH, the downlink transmission method may also include: determining at least one of the following transmission modes according to the first type of PDSCH: performing early data transmission EDT in RRC idle state / inactive state, performing early data transmission MT-EDT based on terminal termination in RRC idle state / inactive state, performing early data transmission MO-EDT based on terminal initiation in RRC idle state / inactive state, establishing a wireless resource control RRC connection, performing contention-based random access, performing contention-free random access, performing a 4-step random access channel or a 2-step random access channel, falling back to a specific transmission process under predefined conditions, and / or, determining resource information of PRACH according to the first type of PDSCH, and / or, determining resource information of the second type of PDSCH according to the first type of PDSCH, and / or, determining resource information of ACK according to the first type of PDSCH, and / or, determining a first type of RNTI according to the first type of PDSCH, and / or, determining a second search space according to the first type of PDSCH.

[0020] Optionally, the PRACH resource information included in the first type PDSCH may include at least one of the following information: preamble sequence index, preamble sequence repetition number, PRACH format, PRACH time-frequency resources, synchronization signal for determining RACH timing, and broadcast channel SS / PBCH information.

[0021] Optionally, when the predefined downlink resource is the first search space, before receiving PDCCH in the second search space, the downlink transmission method may also include determining the second search space according to at least one of the following methods: determining the second search space according to configuration information of cell system information, determining the second search space according to configuration information of user equipment dedicated RRC signaling, determining the second search space according to the first type of PDSCH, determining the second search space in combination with the multiple signalings, and determining the second search space according to a predefined search space.

[0022] Optionally, the step of receiving PDCCH in the search space may include: receiving PDCCH according to a first type of RNTI or RA-RNTI, wherein the first type of RNTI is determined by at least one of the following: a first type of RNTI allocated when the user equipment is in an RRC connected state, an RNTI contained in a first type of PDSCH, a C-RNTI allocated the last time the user equipment was in an RRC connected state, a paging user equipment identifier PagingUE-Identity, and a random access RNTI RA-RNTI.

[0023] Optionally, the PDCCH received in the second search space may include at least one of the following: scheduling information of PDSCH, uplink timing adjustment information, uplink channel information for feedback HARQ-ACK, first type RNTI information, and an indication of a user equipment transmission mode, wherein the indication of the user equipment transmission mode includes: an indication of sending PRACH, an indication of receiving PDSCH, and an indication of feedback of HARQ-ACK via PRACH or PUCCH, wherein different indication contents are distinguished by a separate bit field in the DCI of the PDCCH in the second search space, or, different indication contents are distinguished by specific bit values / value combinations in the DCI of the PDCCH in the second search space, or, different indication contents are distinguished by performing CRC scrambling on the PDCCH in the second search space using different RNTIs, or, different indication contents are distinguished by different DCI formats.

[0024] Optionally, after sending the PRACH, the downlink transmission method may further include: when no corresponding downlink response is received in the second search space within the time window, falling back to a contention-based random access process, or, when no corresponding downlink response is received in the second search space within the time window, sending a dedicated PRACH again, or, when no corresponding downlink response is received in the second search space within the time window, entering a sleep state.

[0025] Optionally, the downlink transmission method may also include: determining the resources of the second type of PDSCH based on the resource information of the PDSCH contained in the PDCCH, the resource information of the PDSCH contained in the first type of PDSCH, or at least one set of PDSCH resource information configured by the base station in the RRC connection state, or determining the resources of the second type of PDSCH based on the PRACH.

[0026] Optionally, the second type of PDSCH may include at least one of the following: downlink data, uplink channel information for carrying ACK, uplink timing adjustment information, uplink scheduling information, the first type of RNTI, and Msg B PDSCH in a two-step random process, wherein the second type of PDSCH is encrypted according to the first type of RNTI, and / or RA-RNTI, and / or cell ID, and / or a sequence determined by PRACH.

[0027] Optionally, parameters of the third search space are optionally configured, and if the parameters of the specific search space are not configured, a search space for a predefined purpose is used as the specific search space, wherein the third search space is determined based on user equipment-specific RRC signaling, or the third search space is determined based on cell system information, or the third search space is determined based on user equipment-specific parameters and common search space parameters.

[0028] Optionally, when the predefined downlink resource is a predefined second-category PDSCH resource, the predefined second-category PDSCH resource is configured by the base station when the user equipment is in an RRC connected state, and can be used for downlink transmission in an RRC idle / inactive state.

[0029] Optionally, when the predefined downlink resource is a predefined second-type PDSCH resource, the predefined second-type PDSCH resource is indicated by a RAR PDCCH in a two-step random access process. The second-type PDSCH is a Msg B RAR PDSCH in a two-step random access process. Optionally, the step of providing ACK feedback according to the demodulation result may include: if the PDSCH is demodulated correctly, sending ACK; if the PDSCH is not demodulated correctly, not sending an uplink signal, or, according to the demodulation result of the PDSCH, sending ACK or NACK.

[0030] Optionally, when the second type of PDSCH is Msg B RAR PDSCH, the step of performing ACK feedback according to the demodulation result may include: when the UE demodulates a successful Msg B RAR sPDU in Msg B RAR PDSCH, the UE feeds back ACK. According to the HARQ-ACK timing indicated in the RARPDSCH or RAR PDCCH and the predefined time offset, determine the uplink time slot / sub-time slot for feeding back ACK.

[0031] Optionally, ACK and NACK may be carried by PRACH or PUCCH, or ACK may be carried by PUSCH.

[0032] Optionally, the downlink transmission method may further include: judging whether to send PUCCH according to whether the uplink timing is valid, wherein if the uplink timing is valid, sending PUCCH carrying ACK or NACK according to the uplink timing, and if the uplink timing fails, not sending PUCCH; or, if the uplink timing is valid, sending PUCCH carrying ACK or NACK according to the uplink timing, and if the uplink timing fails, sending PRACH and not sending PUCCH.

[0033] Optionally, after receiving the second type of PDSCH, the downlink transmission method may further include: monitoring PDCCH in the second or third search space within a predetermined time window, wherein the predetermined time window starts from any one of the following items: the end symbol of the uplink channel for ACK feedback by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the uplink channel for ACK feedback by the user equipment is located, the end symbol of the PDSCH sent by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the PDSCH sent by the user equipment is located, the end symbol of the PUSCH sent by the user equipment, and the end position of the time slot / sub-time slot where the end symbol of the PUSCH sent by the user equipment is located.

[0034] Optionally, the downlink transmission method may also include: receiving at least one of the following items sent by the base station within a predetermined time window: downlink control channel resource configuration information, PRACH configuration information, uplink channel configuration information of ACK feedback, scheduling information of the second type of PDSCH, scheduling information of PUSCH, transmission mode indication information, PRACH transmission trigger information, trigger information of a contention-based random access process, indication information for entering a sleep state, or the step of entering a sleep state includes: entering a sleep state when no PDCCH is received within a predetermined time window or when indication information for entering a sleep state is received.

[0035] Optionally, the downlink transmission method may further include: falling back to a contention-based random access process according to a received fallback indication or based on the detection of a fallback trigger condition, wherein the fallback trigger condition includes at least one of the following: uplink timing failure, receiving a PDCCH scheduling a second type of PDSCH but uplink timing failure, and no response is received within a predefined time window after sending a contention-free PRACH.

[0036] According to an exemplary embodiment of the present disclosure, a user equipment is provided, comprising: a signal receiving unit configured to receive a predefined downlink signal in a predefined downlink resource; and a feedback unit configured to perform ACK feedback according to the received downlink signal.

[0037] Optionally, the predefined downlink signal is a second type PDSCH, and the feedback unit can be configured to demodulate the second type PDSCH and provide ACK feedback based on the demodulation result, or the user equipment further includes: a sleep unit configured to enter a sleep state when a predefined sleep condition is met.

[0038] Optionally, the predefined downlink resource is a predefined second-category PDSCH resource, or the predefined downlink resource is a first search space, which is a paging search space for monitoring the PDCCH that schedules the first-category PDSCH, or the predefined downlink resource is a third search space, which is a search space for monitoring the PDCCH that schedules the second-category PDSCH and for supporting the reception of the PDCCH for downlink transmission by the user equipment when the user equipment is in an RRC idle / deactivated state.

[0039] Optionally, the signal receiving unit may include: a third PDCCH receiving unit, configured to receive a predefined PDCCH in a third search space when the predefined downlink resource is a third search space; a third PDSCH receiving unit, configured to receive a second type of PDSCH according to the PDCCH received in the third search space, wherein the signal receiving unit may include: a first PDCCH receiving unit, configured to receive a predefined PDCCH in a first search space when the predefined downlink resource is a first search space; a first PDSCH receiving unit, configured to receive a first type of PDSCH according to the PDCCH received in the first search space; a second receiving unit, configured to receive a second type of PDSCH, or, wherein the second receiving unit may include: a second PDCCH receiving unit, configured to receive a PDCCH in a second search space; a second PDSCH receiving unit, configured to receive a second type of PDSCH according to the PDCCH received in the second search space, or, wherein the user equipment further includes: a PRACH sending unit, configured to send PRACH according to the first type of PDSCH.

[0040] Optionally, the signal receiving unit may include: a first PDCCH receiving unit, configured to receive a predefined PDCCH in a first search space when the predefined downlink resource is a first search space; a first PDSCH receiving unit, configured to receive a first type of PDSCH according to the PDCCH received in the first search space; a PRACH sending unit, configured to send PRACH according to the first type of PDSCH; a PDCCH monitoring unit, configured to monitor PDCCH in a predefined second search space within a predetermined time window; a second PDCCH receiving unit, configured to receive PDCCH in a second search space when PDCCH is monitored within a predetermined time window; a second PDSCH receiving unit, configured to receive a second type of PDSCH when the PDCCH received in the second search space indicates reception of a second type of PDSCH; or, the sleep unit is configured to enter a sleep state when the PDCCH received in the second search space indicates entering a sleep state, or, the sleep unit is configured to enter a sleep state when PDCCH is not monitored within a predetermined time window.

[0041] Optionally, downlink data may be included in the first type of PDSCH, and / or the first type of PDSCH includes at least one of the following information: PRACH resource information, second type of PDSCH resource information, ACK resource information, transmission mode information, first type of RNTI, second search space resource information, and / or the user equipment further includes: a mode determination unit, configured to determine at least one of the following transmission modes according to the first type of PDSCH after receiving the first type of PDSCH: performing early data transmission EDT in RRC idle state / inactive state, performing early data transmission MT-EDT based on terminal end in RRC idle state / inactive state, performing RR C Early data transmission MO-EDT initiated by the terminal in idle state / inactive state, establishing a wireless resource control RRC connection, performing contention-based random access, performing contention-free random access, performing a 4-step random access channel or a 2-step random access channel, and falling back to a specific transmission process under predefined conditions, and / or determining the resource information of PRACH according to the first type of PDSCH, and / or determining the resource information of the second type of PDSCH according to the first type of PDSCH, and / or determining the resource information of ACK according to the first type of PDSCH, and / or determining the first type of RNTI according to the first type of PDSCH, and / or determining the second search space according to the first type of PDSCH.

[0042] Optionally, the PRACH resource information included in the first type PDSCH may include at least one of the following information: preamble sequence index, preamble sequence repetition number, PRACH format, PRACH time-frequency resources, synchronization signal for determining RACH timing, and broadcast channel SS / PBCH information.

[0043] Optionally, the user equipment may also include: a space determination unit, configured to determine the second search space according to at least one of the following methods when the predefined downlink resource is the first search space: determining the second search space according to the configuration information of the cell system information, determining the second search space according to the configuration information of the user equipment dedicated RRC signaling, determining the second search space according to the first type of PDSCH, determining the second search space in combination with the multiple signalings, and determining the second search space according to the predefined search space.

[0044] Optionally, the signal receiving unit or the first PDCCH receiving unit, the second PDCCH receiving unit, and the third PDCCH receiving unit in the signal receiving unit can be configured to: receive PDCCH according to the first type of RNTI or RA-RNTI, wherein the first type of RNTI is determined by at least one of the following: the first type of RNTI allocated when the user equipment is in the RRC connected state, the RNTI contained in the first type of PDSCH, the C-RNTI allocated the last time the user equipment was in the RRC connected state, the paging user equipment identity PagingUE-Identity and the random access RNTI RA-RNTI.

[0045] Optionally, the PDCCH received in the second search space may include at least one of the following: scheduling information of PDSCH, uplink timing adjustment information, uplink channel information for feedback HARQ-ACK, first type RNTI information, and an indication of a user equipment transmission mode, wherein the indication of the user equipment transmission mode includes: an indication of sending PRACH, an indication of receiving PDSCH, and an indication of feedback of HARQ-ACK via PRACH or PUCCH, wherein different indication contents are distinguished by a separate bit field in the DCI of the PDCCH in the second search space, or, different indication contents are distinguished by specific bit values / value combinations in the DCI of the PDCCH in the second search space, or, different indication contents are distinguished by performing CRC scrambling on the PDCCH in the second search space using different RNTIs, or, different indication contents are distinguished by different DCI formats.

[0046] Optionally, the user equipment may also include: a fallback unit, configured to fall back to a contention-based random access process when no corresponding downlink response is received in the second search space within the time window, or the user equipment also includes: a retransmission unit, configured to retransmit a dedicated PRACH when no corresponding downlink response is received in the second search space within the time window, or the sleep unit is further configured to enter a sleep state when no corresponding downlink response is received in the second search space within the time window.

[0047] Optionally, the user equipment may also include: a resource determination unit, configured to determine the resources of the second type of PDSCH based on the resource information of the PDSCH contained in the PDCCH, the resource information of the PDSCH contained in the first type of PDSCH, or at least one set of PDSCH resource information configured by the base station in the RRC connection state, or to determine the resources of the second type of PDSCH based on the PRACH.

[0048] Optionally, the second type of PDSCH may include at least one of the following: downlink data, uplink channel information for carrying ACK, uplink timing adjustment information, uplink scheduling information, and the first type of RNTI, wherein the second type of PDSCH is encrypted according to the first type of RNTI, and / or RA-RNTI, and / or cell ID, and / or a sequence determined by PRACH.

[0049] Optionally, parameters of the third search space are optionally configured, and if the parameters of the specific search space are not configured, a search space for a predefined purpose is used as the specific search space, wherein the third search space is determined based on user equipment-specific RRC signaling, or the third search space is determined based on cell system information, or the third search space is determined based on user equipment-specific parameters and common search space parameters.

[0050] Optionally, when the predefined downlink resource is a predefined second-category PDSCH resource, the predefined second-category PDSCH resource is configured by the base station when the user equipment is in an RRC connected state, and can be used for downlink transmission in an RRC idle / inactive state.

[0051] Optionally, the feedback unit may be configured to: send ACK if the PDSCH is demodulated correctly; not send an uplink signal if the PDSCH is not demodulated correctly, or send ACK or NACK according to the demodulation result of the PDSCH.

[0052] Optionally, ACK and NACK may be carried by PRACH or PUCCH, or ACK may be carried by PUSCH.

[0053] Optionally, the user equipment may also include: a sending judgment unit, configured to judge whether to send PUCCH according to whether the uplink timing is valid, wherein if the uplink timing is valid, the PUCCH carrying ACK or NACK is sent according to the uplink timing; if the uplink timing fails, the PUCCH is not sent; or, if the uplink timing is valid, the PUCCH carrying ACK or NACK is sent according to the uplink timing; if the uplink timing fails, PRACH is sent and PUCCH is not sent.

[0054] Optionally, the user equipment may also include: a PDCCH monitoring unit, configured to monitor PDCCH in the second or third search space within a predetermined time window, wherein the predetermined time window starts from any one of the following items: the end symbol of the uplink channel for ACK feedback by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the uplink channel for ACK feedback by the user equipment is located; the end symbol of the PDSCH sent by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the PDSCH sent by the user equipment is located, the end symbol of the PUSCH sent by the user equipment, and the end position of the time slot / sub-time slot where the end symbol of the PUSCH sent by the user equipment is located.

[0055] Optionally, the user equipment may also include: an information receiving unit, configured to receive at least one of the following items sent by the base station within a predetermined time window: downlink control channel resource configuration information, PRACH configuration information, uplink channel configuration information of ACK feedback, scheduling information of the second type of PDSCH, scheduling information of PUSCH, transmission mode indication information, PRACH transmission trigger information, trigger information of a contention-based random access process, indication information for entering a sleep state, or the sleep unit is further configured to enter a sleep state if no PDCCH is received within a predetermined time window, or when indication information for entering a sleep state is received.

[0056] Optionally, the fallback unit can also be configured to fall back to the contention-based random access process according to a received fallback indication or based on the detection of a fallback trigger condition, wherein the fallback trigger condition includes at least one of the following: uplink timing failure, receiving a PDCCH scheduling a second type of PDSCH but uplink timing failure, and no response is received within a predefined time window after sending a contention-free PRACH.

[0057] According to an exemplary embodiment of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the downlink transmission method according to the present disclosure are implemented.

[0058] According to an exemplary embodiment of the present disclosure, a computing device is provided, including: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, the steps of the downlink transmission method according to the present disclosure are implemented.

[0059] According to the downlink transmission method and user equipment performed by the exemplary embodiments of the present disclosure, by receiving a predefined downlink signal in a predefined downlink resource and performing ACK feedback according to the received downlink signal, downlink data transmission is achieved in the RRC idle or inactive state.

[0060] Additional aspects and / or advantages of the present general inventive concept will be set forth in part in the following description and in part will be apparent from the description or may be learned through practice of the present general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The above and other objects and features of the exemplary embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings which exemplarily illustrate the embodiments, in which:

[0062] Figure 1 A flowchart showing a downlink transmission method performed by a user equipment UE according to an exemplary embodiment of the present disclosure is shown;

[0063] Figure 2 A flowchart showing a downlink transmission method performed by a user equipment UE according to another exemplary embodiment of the present disclosure is shown;

[0064] Figure 3 A flowchart showing a downlink transmission method performed by a user equipment UE according to another exemplary embodiment of the present disclosure is shown;

[0065] Figure 4 A flowchart showing a downlink transmission method performed by a user equipment UE according to another exemplary embodiment of the present disclosure is shown;

[0066] Figure 5 A block diagram showing a user equipment according to an exemplary embodiment of the present disclosure;

[0067] Figure 6 A block diagram showing a user equipment according to another exemplary embodiment of the present disclosure;

[0068] Figure 7 A block diagram showing a user equipment according to another exemplary embodiment of the present disclosure;

[0069] Figure 8 A block diagram showing a user equipment according to another exemplary embodiment of the present disclosure; and

[0070] Fig. 9A schematic diagram showing a computing device according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0071] Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments will be described below with reference to the drawings in order to explain the present disclosure.

[0072] In the NR system, the UE can be in the RRC connected state (connected), the RRC inactive state (inactive), and the RRC idle state (idle). Compared with LTE, NR newly introduces the RRC Inactive state, and the signaling bearer and data connection can be restored through the RRC connection recovery (RRC Resume) process. In the prior art, a UE in the RRC idle state or an inactive state (inactive) only needs to monitor the paging signal (Paging) periodically. The UE does not need to monitor other physical downlink control channels (Physical Downlink Control Channel, referred to as PDCCH), nor does it need to receive unicast downlink data. There are two main types of UE paging messages. The first type is the paging message from the Radio Access Network (RAN), which mainly includes system information update, Earthquake and Tsunami Warning System (EWTS) indication, and Commercial Mobile Alert Service (CMAS) indication. The second type is the paging message from the Core Network (CN), which mainly includes the UE ID being paged, that is, the temporary mobile user identification code (SAE-Temporary Mobile Subscriber Identity, S-TMSI) or the International Mobile Subscriber Identification Number (IMSI), and indicates whether the paging comes from the packet switching domain (PS) or the circuit switching domain (CS). For paging messages from the RAN side, all idle UEs in the cell need to receive them; for paging messages from the CN side, only the UE being paged needs to receive them, and other UEs do not need to receive them.

[0073] In order to support UE to receive downlink data sent by the base station in RRC idle state / inactive state, a more common method is to enhance it based on the existing paging mechanism. Regardless of whether the UE is stationary or has mobile characteristics (the service cell may change), the paging-based mechanism can find the UE and perform subsequent communication operations. Another simpler method is that based on the UE information known by the service cell base station, the base station directly sends a downlink signal to the UE. This method is more suitable for UE with stationary characteristics. In addition, in actual systems, due to different reasons for triggering downlink transmission, for example, downlink transmission caused by terminal-terminated downlink services (Mobile-terminated, referred to as MT), or downlink transmission caused by terminal-initiated services (Mobile-originated, referred to as MO), the corresponding downlink transmission methods may be different.

[0074] The present disclosure provides a variety of flexible technical solutions to support various scenarios. For example, the base station can support multiple downlink transmission methods and flexible selection. The base station indicates the downlink transmission mode through high-level signaling, and the base station can indicate which downlink transmission mode the UE adopts through RRC signaling or MAC signaling when the UE is in a connected state (RRC connection). For another example, the base station can indicate which downlink transmission mode the UE adopts through a paging message / PDCCH for paging / reference signal or sequence for paging / specific PDCCH when the UE is in an idle state (RRC idle) or an inactive state (RRC inactive). The base station can indicate the downlink transmission mode through a UE-specific channel or signal, or through a UE group-specific channel or signal, or through a common channel or signal. For example, the base station can indicate the supportable downlink transmission mode through a system message.

[0075] Specifically, the parameters of the downlink transmission mode may be configured by the base station. For example, the system information includes the parameters of the downlink transmission mode supported by the base station, or the parameters of the available downlink transmission mode indicated in the UE-specific high-layer signaling.

[0076] Specifically, the available downlink transmission mode can be determined according to the downlink transmission mode indicated by the base station and the predefined conditions. For example, the base station indicates M downlink transmission modes in the system message, and one of the M downlink transmission modes can be uniquely determined according to different predefined conditions.

[0077] Specifically, the downlink transmission mode may include downlink transmission performed when the UE switches from an RRC idle state / inactive state to an RRC connected state, and downlink transmission performed when the UE remains in the RRC idle state / inactive state.

[0078] Specifically, the UE transitions from the RRC idle state / inactive state to the RRC connected state, or the UE maintains downlink transmission in the RRC idle state / inactive state, which may include the UE following a four-step random access procedure (4-step RACH) or a two-step random access procedure (2-step RACH).

[0079] Specifically, the base station may instruct the UE to maintain a specific downlink transmission mode in the RRC idle state / inactive state. For example, the MT-EDT mode of early data transmission based on terminal termination in the RRC idle state / inactive state, or the MO-EDT mode of early data transmission based on terminal initiation in the RRC idle state / inactive state, or the data transmission mode based on pre-configured search space in the RRC idle state / inactive state, or the data transmission mode based on pre-configured downlink resources in the RRC idle state / inactive state.

[0080] Specifically, the UE may determine the transmission mode according to whether the uplink timing is valid.

[0081] Specifically, the UE may report UE type information to the base station. Here, the UE type information includes whether the UE has a stationary characteristic.

[0082] There are multiple methods for obtaining downlink transmission resources in the RRC idle state / inactive state for downlink transmission in the RRC idle state / inactive state, and these methods can be used in combination. For example, resource information for downlink transmission in the RRC idle state / inactive state is obtained in the RRC connection state, and this resource information is still retained when the RRC connection is released, so that it can be used when downlink transmission is performed in the RRC idle state / inactive state. For example, resource information for downlink transmission in the RRC idle state / inactive state is obtained in the RRC idle state / inactive state, and this resource information is only valid for a certain period of time.

[0083] Figure 1 A flow chart of a downlink transmission method performed by a user equipment UE according to an exemplary embodiment of the present disclosure is shown.

[0084] Reference Figure 1 , in step S101, a predefined PDCCH is received in a predefined first search space.

[0085] The predefined first search space is a search space for monitoring paging control information (also referred to as paging search space, pagingSearchSpace). When the UE is in the RRC idle / deactivated state, the UE can operate in a discontinuous reception mode (DRX) to achieve the purpose of power saving. At this time, the UE only needs to monitor one paging occasion (paging occasion, referred to as PO) in each DRX cycle. This paging occasion consists of a group of downlink control information PDCCH monitoring occasions (PDCCHmonitoring occasions). In a paging frame (paging frame, referred to as PF), one or more POs may be included, or the starting points of one or more POs may be included.

[0086] In an exemplary embodiment of the present disclosure, in the first search space, the predefined downlink signal may be a PDCCH. In one PO, the base station may send one or more PDCCHs scrambled by a paging RNTI (P-RNTI). In one or more PDCCHs scrambled by a paging RNTI sent by the base station, the scheduled PDSCH information is indicated.

[0087] In an exemplary embodiment of the present disclosure, the step of receiving the PDCCH in the first search space may include: receiving the PDCCH according to the first type RNTI or the RA-RNTI. Here, the first type RNTI may be determined by at least one of the following: the first type RNTI allocated when the user equipment is in the RRC connected state, the RNTI contained in the first type PDSCH, the C-RNTI allocated when the user equipment was in the RRC connected state last time, the paging user equipment identity PagingUE-Identity and the random access RNTI RA-RNTI.

[0088] In an exemplary embodiment of the present disclosure, PDCCH may indicate UE behavior. For example, PDCCH indicates that the UE receives the PDSCH scheduled by this PDCCH (for example, PDCCH indicates that DCI contains scheduling information of a paging message), or only receives PDCCH (for example, PDCCH indicates that DCI contains scheduling information of a short message but does not contain a paging message). For example, PDCCH indicates that the UE performs contention-based random access or contention-free random access. For example, PDCCH indicates that the UE performs 4-step RACH or 2-step RACH. For example, PDCCH indicates that the UE performs transmission in RRC idle state / inactive state, or establishes an RRC connection. For example, PDCCH indicates whether PDSCH contains downlink data. For example, PDCCH indicates whether PDSCH contains downlink control information for scheduling downlink data, etc. If PDCCH corresponds to a group of UEs, the behavior of this group of UEs is the same. Alternatively, if the PDCCH contains behavior indications for multiple sub-groups of UEs into which a group of UEs is further divided, the behavior of the UEs in each sub-group is the same, but the behavior of UEs in different sub-groups may be different.

[0089] In an exemplary embodiment of the present disclosure, in the first search space, the predefined downlink signal may be a wake-up signal (WUS for short). In a PO, or starting from X time slots / sub-time slots / symbols / absolute times before a PO, the base station may send a WUS. The base station may allocate the same one or a group of WUS to one or a group of UEs. Optionally, the WUS indicates UE behavior. For example, different behaviors of the UE are indicated by different WUS sequences. Alternatively, different behaviors of the UE are determined by different WUS sequences and indications in the PDCCH. For example, the base station may configure multiple tables, each table corresponding to a WUS sequence or UE group, and each table including UE behaviors in X. The UE determines which table and which UE behavior in this table through the WUS sequence and the log2(X) bits in the PDCCH.

[0090] Specifically, if the base station does not indicate the UE behavior in the PDCCH or the WUS, the UE may operate according to the behavior predefined in the standard.

[0091] In addition, the PDCCH or WUS may indicate information of the search space. For example, the base station may configure resource information and the search space ID of the second search space for the UE when in a connected state. Here, the ID of the second search space may be indicated by the PDCCH or WUS in an explicit, implicit, or combined manner. For example, the ID of the second search space may be determined based on the position of the first CCE of the PDCCH.

[0092] In step S102, a first-type PDSCH is received according to a PDCCH received in a first search space.

[0093] If the UE receives a PDCCH in step S101, and the UE behavior indicated by the PDCCH includes receiving a PDSCH, the UE receives a first-type PDSCH according to the PDCCH in step S102. The first-type PDSCH is a PDSCH carrying a paging message.

[0094] In an exemplary embodiment of the present disclosure, downlink data may be included in the first type PDSCH.

[0095] In an exemplary embodiment of the present disclosure, the first type PDSCH may include at least one of the following information: resource information of PRACH, resource information of the second type PDSCH, ACK resource information, transmission mode information, first type RNTI, and resource information of the second search space.

[0096] In an exemplary embodiment of the present disclosure, after receiving the first type of PDSCH, the downlink transmission method also includes: determining at least one of the following transmission modes according to the first type of PDSCH: performing early data transmission EDT in RRC idle state / inactive state, performing early data transmission MT-EDT based on terminal termination in RRC idle state / inactive state, performing early data transmission MO-EDT based on terminal initiation in RRC idle state / inactive state, establishing a wireless resource control RRC connection, performing contention-based random access, performing contention-free random access, performing a 4-step random access channel or a 2-step random access channel, and falling back to a specific transmission process when predefined conditions are met.

[0097] In an exemplary embodiment of the present disclosure, resource information of the PRACH may be determined according to the first type PDSCH.

[0098] In an exemplary embodiment of the present disclosure, resource information of the second type PDSCH may be determined according to the first type PDSCH.

[0099] In an exemplary embodiment of the present disclosure, resource information of ACK may be determined according to the first type PDSCH.

[0100] In an exemplary embodiment of the present disclosure, the first type RNTI may be determined according to the first type PDSCH.

[0101] In an exemplary embodiment of the present disclosure, the second search space may be determined according to the first type PDSCH.

[0102] In an exemplary embodiment of the present disclosure, the resource information of PRACH contained in the first type of PDSCH may include at least one of the following information: a preamble sequence index, a preamble sequence repetition number, a PRACH format, a PRACH time-frequency resource, a synchronization signal for determining the RACH timing, and broadcast channel SS / PBCH information.

[0103] In an exemplary embodiment of the present disclosure, in the first type of PDSCH, the base station may instruct the UE to send resource information of PRACH, and / or send resource information of the second type of PDSCH, and / or feedback resource information of HARQ-ACK, and / or send downlink data contained in the first PDSCH.

[0104] In addition, in the first type of PDSCH, the base station can indicate the UE behavior. Specifically, the first type of PDSCH can indicate the transmission mode: the UE performs transmission in the RRC idle state / inactive state (for example, including MT-EDT indication), or establishes an RRC connection. Specifically, the first type of PDSCH can also instruct the UE to perform contention-based random access, or to perform contention-free random access. Specifically, the first type of PDSCH can also instruct the UE to perform 4-step RACH or 2-step RACH. Specifically, the first type of PDSCH can also indicate the transmission mode of the UE in the RRC idle state / inactive state. For example, the transmission mode of the UE in the RRC idle state / inactive state is a transmission mode based on MT-EDT, or a transmission mode based on MO-EDT. Specifically, the first type of PDSCH can also indicate that the UE falls back to a contention-based random access process under predefined conditions. For example, when the UE does not receive any PDCCH within the time window T2 after sending the PRACH, the UE falls back to a contention-based random access process. Specifically, the transmission mode can be indirectly indicated by whether specific information is contained in the first type of PDSCH. For example, if the first type of PDSCH contains dedicated PRACH resource information and / or the first type of RNTI, the transmission mode is MT-EDT-based transmission in RRC idle state / inactive state, and if the first type of PDSCH does not contain dedicated PRACH resource information, the transmission mode is MO-EDT-based transmission in RRC idle state / inactive state. Specifically, if the first type of PDSCH does not contain information indicating UE behavior, the UE can operate according to the behavior predefined by the standard, for example, perform a random access process and establish or restore an RRC connection.

[0105] In an exemplary embodiment of the present disclosure, resource information of the PRACH may be included in the first type PDSCH.

[0106] Here, the resource information of the PRACH contained in the first type of PDSCH may include at least one of the following information: a preamble index, a preamble repetition count, a PRACH format, and a PRACH time-frequency resource. For example, the time resource of the PRACH contained in the first type of PDSCH is a time resource with a length of Y symbols, starting from the first symbol after X time slots and / or symbols of the downlink time unit boundary where the end symbol of the first type of PDSCH received in step S102 or the end symbol is located, and the frequency domain resources of the PRACH are from the mth to the PRB to the nth PRB.

[0107] In addition, the resource information of the PRACH contained in the first type of PDSCH includes the resource information of the PRACH of the SS / PBCH index, which is used to determine the RACH timing for sending the PRACH, where the RACH timing corresponds to the SS / PBCH index. Specifically, the SS / PBCH index information can be indicated by N bits. Here, a specific N-bit value indicates that the SS / PBCH index corresponding to the RACH timing is the same as the SS / PBCH index corresponding to the received paging message. For example, when the N-bit value is 0, it indicates that the SS / PBCH index corresponding to the RACH timing is the same as the SS / PBCH index corresponding to the received paging message. When the N-bit value is i, it indicates that the SS / PBCH index corresponding to the RACH timing is i.

[0108] In addition, the resource information including the PRACH in the first type PDSCH may also include power control information, such as parameters such as preambleReceivedTargetPower.

[0109] In an exemplary embodiment of the present disclosure, the base station may configure PRACH resources for the UE when the UE is in an RRC connected state. When the UE releases the RRC connection, the PRACH resources are not released. The base station instructs the UE in the first type of PDSCH to use the configured PRACH resources for PRACH transmission. The UE transmits PRACH according to the PRACH resources indicated above. The base station may indicate in the first type of PDSCH whether the UE uses the configured PRACH resources for PRACH transmission.

[0110] In an exemplary embodiment of the present disclosure, when the UE is in an RRC connected state, the base station may configure multiple sets of PRACH resources for the UE. When the UE releases the RRC connection, the PRACH resources are not released. The base station may indicate which set of resources the UE uses for PRACH transmission in the first type of PDSCH.

[0111] In an exemplary embodiment of the present disclosure, the UE may determine the PRACH time-frequency code resources and the effective RACH timing for sending PRACH according to the PRACH resources indicated above and the PRACH resource configuration information indicated in the system information or cell common signaling of the serving cell (the resident cell in the RRC idle state) of the UE in the RRC idle / inactive state. Further, in order to shorten the delay, the RACH timing selected by the UE is the first effective RACH timing that meets the predefined delay after the end of the first type of PDSCH received in step S102. The predefined delay is predefined by the standard or configured by the base station.

[0112] In an exemplary embodiment of the present disclosure, when the base station includes PRACH resource information in the first type of PDSCH, a predefined value may be used to indicate whether the PRACH resource is contention-based or dedicated to a UE. For example, if the value of the preamble index is set to 0, the PRACH resource is contention-based, and the UE will perform a 4-step contention-based random access procedure or a 2-step contention-based random access procedure.

[0113] In an exemplary embodiment of the present disclosure, an RNTI may be included in the first type of PDSCH for use in subsequent steps of the communication process of the UE in the current RRC idle / inactive state. Specifically, if the UE does not change the serving cell (the resident cell in the RRC idle state) and the UE does not receive a new RNTI, the UE may continue to use this RNTI in the next communication process in the RRC idle / inactive state. The UE may receive the PDCCH according to the RNTI. For example, the RNTI is used for CRC scrambling of the PDCCH and determining the DMRS sequence. For example, the UE may determine the starting point of the UE-specific search space according to the RNTI. For example, the UE may scramble the PUSCH, or the PUCCH, or the second type of PDSCH according to the RNTI, and the UE may determine the DMRS sequence according to the predefined RNTI. For the convenience of description, this RNTI may be referred to as the first type of RNTI.

[0114] In an exemplary embodiment of the present disclosure, information of the second search space may be included in the first type PDSCH. Specifically, the information of the second search space includes at least one of the following information: search space ID, time resource information (e.g., period, offset, time length, symbols occupied within a time unit, etc.), frequency domain resource information (e.g., occupied PRB), space resource information (e.g., QCL / TCI information, precoding granularity, etc.), CCE-REG-mapping information, PDCCH DMRS information, aggregation level information of the search space, monitoring candidate number information, and DCI format information.

[0115] In an exemplary embodiment of the present disclosure, the base station may configure the resource information of the search space and the search space ID for the UE when the UE is in a connected state. When the UE releases the RRC connection, the resource information of the search space and the search space ID are not released. The UE may indicate the information of the second search space in combination with the indication of the first type of PDSCH and the information configured by the base station for the UE when the UE is in a connected state. For example, the base station may indicate the information of the second search space by using the information configured for the UE when the UE is in a connected state and the search space ID indicated by the first type of PDSCH. The indication may be explicit, implicit, or a combination of both.

[0116] In an exemplary embodiment of the present disclosure, resource information of the second type of PDSCH is referred to in the first type of PDSCH. Therefore, after the UE receives the first type of PDSCH in step S102, it can skip steps S103 and S104 and directly enter step S105. Alternatively, after the UE receives the first type of PDSCH in step S102, it still enters step S103. For example, if the PRACH time resource configured by the base station is earlier than the time resource of the second type of PDSCH, the base station can determine the cell where the UE is located after receiving the PRACH, and only send the second type of PDSCH carrying downlink data in the cell, thereby avoiding the base station from sending the second type of PDSCH in multiple cells.

[0117] In an exemplary embodiment of the present disclosure, when the UE is in an RRC connection state, the base station configures multiple sets of PDSCH resource information for the UE, which at least includes the time-frequency resources of the PDSCH, the information of the transport block TB carried by the PDSCH (such as MCS information), reference symbol information, etc. When the UE releases the RRC connection, the resource information of the PDSCH is not released. The base station may indicate in the first type of PDSCH which set of PDSCH resources the UE uses for PDSCH reception. The UE may receive PDSCH according to a set of PDSCH resources indicated by the base station. Specifically, when the UE is in an RRC connection state, the base station may configure a set of partial resource information of the PDSCH, and when the UE releases the RRC connection, the resource information of the PDSCH is not released. The base station may include the remaining resource information in the first type of PDSCH. The UE may determine the resources of the second type of PDSCH based on two types of information.

[0118] In an exemplary embodiment of the present disclosure, when the UE is in an RRC connected state, the base station configures multiple sets of PDSCH resource information for the UE, which at least includes the time-frequency resources of the PDSCH, the information of the transport block TB carried by the PDSCH (such as MCS information), the reference symbol information, and the corresponding SS / PBCH information, etc. For one SS / PBCH, there are multiple sets of PDSCH resource information. When the UE releases the RRC connection, the resource information of the PDSCH is not released. The base station can indicate in the first type of PDSCH which set of PDSCH resources the UE uses for PDSCH reception. The UE can receive the PDSCH according to the index number i of the SS / PBCH corresponding to the received first type of PDSCH and the PDSCH resource information indicated by the base station.

[0119] In addition, the first type of PDSCH may include a QCL (Quasi-colocated) characteristic of the second type of PDSCH, for example, which SS / PBCH satisfies the QCL relationship.

[0120] In an exemplary embodiment of the present disclosure, resource information of HARQ-ACK is included in the first type PDSCH. Specifically, the HARQ-ACK information is carried by PUCCH or PRACH.

[0121] Specifically, the base station may configure multiple sets of PUCCH or PRACH resource information for the UE when the UE is in the RRC connection state. When the UE releases the RRC connection, the resource information of the PUCCH or PRACH is not released. The base station may indicate one of the sets of resources in the first type of PDSCH. The indication may be explicit, implicit, or a combination of both. The UE may send the PUCCH or PRACH according to the indicated set of resources.

[0122] Specifically, the signaling for PUCCH or PRACH and the signaling for configuring PUCCH or PRACH resources in RRC connected state can be the same, and the base station will also indicate whether the resource is used for only one of the purposes or can be used for both. In addition, the configuration signaling can also be two different signalings, for example, using different fields (IE) or configured in different RRC messages or system messages.

[0123] Specifically, the PRACH resources used to carry HARQ-ACK are the same as the PRACH resources used to send PRACH. In addition, the PRACH resources used to carry HARQ-ACK and the PRACH resources used to send PRACH can be configured separately.

[0124] In an exemplary embodiment of the present disclosure, downlink data may be carried in the first type PDSCH. At this time, after receiving the first type PDSCH in step S102, the UE skips steps S103 to S105 and directly proceeds to step S106.

[0125] Specifically, if the UE does not monitor the first type PDSCH applicable to the UE, the UE may enter a sleep state. If the UE does not monitor the first type PDSCH applicable to the UE, the UE may monitor the PDCCH in the second search space within a predefined time window.

[0126] In step S103, a PRACH is sent according to the first type of PDSCH.

[0127] When the UE finds information matching itself in the first type PDSCH in step S102, the UE sends the PRACH in step S103. At this time, the UE needs to determine information such as PRACH resources, transmission timing, and power control.

[0128] If the base station allocates a user-specific PRACH resource to the UE when the UE is in a connected state, and the UE does not release the PRACH resource when releasing the RRC connection, then in step S103, the UE sends a PRACH on the PRACH resource.

[0129] If a PRACH resource is indicated in the first type PDSCH in step S102, then in step S103, the UE sends a PRACH on the PRACH resource.

[0130] If contention-based PRACH resources are indicated in the first type of PDSCH in step S102, then in step S103, the UE selects a PRACH resource to send PRACH according to the PRACH resource set configured in the system information and the predefined rules. Here, the signaling for configuring the PRACH resource set used in the downlink transmission in the RRC idle / inactive state and the signaling for configuring the PRACH resource set used for initial access can be the same, and the base station can also indicate whether the PRACH resource set is used for only one of the purposes or both. In addition, the signaling for configuring the PRACH resource set used in the downlink transmission in the RRC idle / inactive state and the signaling for configuring the PRACH resource set used for initial access can also be two different signalings, for example, using different fields (IE) or configured in different system messages.

[0131] If the first type of PDSCH in step S102 includes PRACH power control information, then in step S103, the UE sets the uplink power of PRACH according to the power control parameters indicated by the PRACH power control information included in the first type of PDSCH. If the first type of PDSCH does not include PRACH power control information, the uplink power of PRACH is set according to the power control parameters indicated in the system information. Specifically, the signaling used to configure the PRACH transmit power in step S103 and the signaling used to configure the PRACH transmit power for initial access can be the same, and the base station can also indicate whether the configuration is used for only one of the purposes or for both. In addition, the configuration signaling can be two different signalings, for example, using different fields (IE) or configured in different RRC messages or system messages.

[0132] Specifically, the PRACH resources configured by the base station for the UE can be used for only one uplink transmission. In addition, the PRACH resources configured by the base station for the UE can also be used for multiple uplink transmissions. For example, the base station configures multiple PRACH resources for the UE, and the parameters of each resource can be configured independently, or the base station configures one PRACH resource for the UE and indicates information of multiple transmission locations, such as the time difference between multiple transmission locations, and the number of transmission locations, or the maximum number of times the UE can send PRACH, or it is determined according to the timing of PRACH transmission. After the first PRACH transmission, the UE starts the time window T1 (or timer T1). If the corresponding downlink response has not been received after the time window T1 (or timer T1) returns to 0, it is sent on another (for example, the second) PRACH resource, and so on. If the number of times the UE sends PRACH has reached the predefined maximum number of transmissions, the UE cannot try to send PRACH again.

[0133] Specifically, if the UE does not receive a corresponding downlink response within the time window T2 (or timer T2) after sending the PRACH, the UE may fall back to the contention-based random access procedure. Specifically, the PRACH resources used for the contention-based random access procedure used for downlink transmission in the RRC idle / non-connected state and the PRACH resources used for establishing the RRC connection may be configured separately. Specifically, in the contention-based random access procedure used for downlink transmission in the RRC idle / non-connected state, the base station may carry downlink data in Msg4 of the random access procedure.

[0134] Specifically, time windows T1 and T2 are configured separately, or the two time windows are the same. Time windows T1 and T2 are configured through a dedicated signaling broadcast of the cell system information block instead of the ra-ResponseWindowSize of the existing system, or the ra-ResponseWindowSize of the existing system is reused, or configured through high-layer signaling when the UE is in the RRC connected state.

[0135] In an exemplary embodiment of the present disclosure, when multiple signalings are configured with PRACH, the PRACH information may be determined in combination with the multiple signalings.

[0136] Specifically, when multiple signalings are configured with PRACH, and PRACH information can only be determined according to one configuration information, which signaling determines the PRACH information is determined according to a predefined priority criterion. For example, if the base station allocates a user-specific PRACH to the UE when the UE is in a connected state, and a PRACH information is included in the first type of PDSCH, the UE can send the PRACH according to the PRACH information included in the first type of PDSCH.

[0137] In an exemplary embodiment of the present disclosure, the PRACH may be transmitted according to downlink timing.

[0138] Specifically, the UE may send the PRACH according to the maintained valid uplink timing. If the uplink timing maintained by the UE remains valid, the UE may skip step S103 and directly proceed to step S104 after step S102, or skip step S103 and step S104 and directly proceed to step S105.

[0139] The UE may determine whether the uplink timing is valid based on one or more of the following:

[0140] (1) When the TimeAlignmentTimer in the RRC idle state is no longer running, the uplink timing is invalid.

[0141] (2) Outside the TA validity period (Validity Period) of the RRC idle state, the uplink timing is invalid.

[0142] (3) When the serving cell (the resident cell in the RRC idle state) changes, the uplink timing is invalid.

[0143] (4) When the change in the RSRP measurement value of the serving cell (the resident cell in the RRC idle state) exceeds a predefined threshold, the uplink timing is invalid.

[0144] (5) When the change in the RSRP measurement value of one or more neighboring cells exceeds a predefined threshold, the uplink timing is invalid.

[0145] (6) When the change in the Time Difference of Arrival (TDOA) of signals from at least two base stations exceeds a predefined threshold, the uplink timing is invalid.

[0146] (7) When the UE has a tag indicating a stationary characteristic, the uplink timing is always considered valid.

[0147] (8) When the cell system information indicates that the cell radius is less than a predefined threshold, the uplink timing is always considered valid.

[0148] Here, the TimeAlignmentTimer used to manage the TA refers to the timeAlignmentTimerCommon value indicated in the system information, or the TimeAlignmentTimer used to manage the TA may also be specially configured, for example, the eNB can configure the TimeAlignmentTimerDedicated through the first type PDSCH. During the downlink transmission process in the RRC idle state / inactive state, the UE can obtain the signaling of the TA update. For example, after the UE sends the PRACH, the base station indicates the TA through the PDCCH in the second search space or the second type PDSCH. After the UE receives the signaling of the TA update and adjusts the TA, it restarts the TimeAlignmentTimer. When the TimeAlignmentTimer of the UE is configured to infinity in the RRC connected state, even if the UE enters the RRC idle state, the uplink timing obtained in the RRC connected state can still be saved. In practical applications, due to the actual usage scenarios of IOT UE, the UE is almost relatively static, and the uplink timing used by the UE to send uplink physical channels is almost unchanged. When the UE reports its "static" characteristics to the base station, the base station will configure the TimeAlignmentTimer to infinity based on the "static" characteristics, so that the TA obtained by the UE in the RRC connected state can be used all the time. When the UE releases the RRC connection and enters the RRC idle / deactivated state, the TA is still saved and used for uplink channel transmission in the RRC idle / deactivated state.

[0149] In an exemplary embodiment of the present disclosure, the base station may configure the BWP for sending PRACH, or the base station may limit the UE to send PRACH on the initial BWP, that is, the UL BWP for initial random access indicated in the serving cell system information.

[0150] Specifically, if the UE behavior configured by the base station or the UE behavior indicated in the first type PDSCH is to receive the PDCCH in step S104 or the PDSCH in step S105 according to the paging message, the UE skips step S103 or skips steps S103 and S104.

[0151] In step S104, a PDCCH is received in a predefined second search space.

[0152] In an exemplary embodiment of the present disclosure, before receiving the PDCCH in the second search space,

[0153] The downlink transmission method also includes determining the second search space according to at least one of the following methods: determining the second search space according to configuration information of cell system information, determining the second search space according to configuration information of user equipment dedicated RRC signaling, determining the second search space according to the first type of PDSCH, determining the second search space in combination with the multiple signalings, and determining the second search space according to a predefined search space.

[0154] In an exemplary embodiment of the present disclosure, the step of receiving the PDCCH in the second search space may include: receiving the PDCCH according to the first type RNTI or the RA-RNTI. Here, the first type RNTI may be determined by at least one of the following: the first type RNTI allocated when the user equipment is in the RRC connected state, the RNTI contained in the first type PDSCH, the C-RNTI allocated when the user equipment was in the RRC connected state last time, the paging user equipment identity PagingUE-Identity and the random access RNTI RA-RNTI.

[0155] In an exemplary embodiment of the present disclosure, the PDCCH received in the second search space may include at least one of the following: scheduling information of PDSCH, uplink timing adjustment information, uplink channel information of feedback HARQ-ACK, first type RNTI information, and an indication of the user equipment transmission mode.

[0156] In an exemplary embodiment of the present disclosure, the indication of the transmission mode of the user equipment may include: an indication of sending a PRACH, an indication of receiving a PDSCH, and an indication of feeding back a HARQ-ACK via a PRACH or a PUCCH.

[0157] In an exemplary embodiment of the present disclosure, different indication contents may be distinguished by a separate bit field in the DCI of the PDCCH in the second search space, or, different indication contents may be distinguished by a specific bit value / value combination in the DCI of the PDCCH in the second search space, or, different indication contents may be distinguished by performing CRC scrambling on the PDCCH in the second search space through different RNTIs, or, different indication contents may be distinguished by different DCI formats.

[0158] In an exemplary embodiment of the present disclosure, when no corresponding downlink response is received in the second search space within the time window, fall back to the contention-based random access process, or, when no corresponding downlink response is received in the second search space within the time window, send a dedicated PRACH again, or, when no corresponding downlink response is received in the second search space within the time window, enter a sleep state.

[0159] The second search space is used to receive a PDCCH scrambled by the first type of RNTI, and / or the second search space is used to receive a PDCCH scrambled by the RA-RNTI.

[0160] If the base station configures the second search space through cell system information broadcast, the second search space can be determined according to the configuration information. If the base station configures the second search space through UE-specific RRC signaling, the second search space can be determined according to the configuration information. For example, the base station configures through UE-specific RRC signaling when the UE is in an RRC connected state, and the UE does not release the resource information when releasing the RRC connection.

[0161] If the second search space is configured in the first type PDSCH in step S102, the second search space may be determined according to the indicated information.

[0162] In an exemplary embodiment of the present disclosure, when multiple signalings configure the second search space, the second search space can be determined in combination with the multiple signalings. For example, the second search space can be determined jointly according to the configuration in the first type of PDSCH and the configuration of the cell system information broadcast. For example, the second search space can be determined according to UE-specific parameters and common search space parameters.

[0163] In an exemplary embodiment of the present disclosure, when multiple signalings configure the second search space, and the second search space can only be determined according to one configuration information, which signaling determines the second search space can be determined according to a predefined priority criterion. For example, when the base station configures the second search space through both the first-class PDSCH and the cell system information broadcast, the second search space is determined according to the configuration in the first-class PDSCH. For example, when the base station configures the second search space through both the first-class PDSCH and the UE-specific RRC signaling, the second search space is determined according to the configuration in the first-class PDSCH. For example, when the base station configures the second search space through both the UE-specific RRC signaling and the cell system information broadcast, the second search space is determined according to the UE-specific RRC signaling.

[0164] In an exemplary embodiment of the present disclosure, the signaling for configuring the second search space and the signaling for configuring other search spaces may be the same, and the base station may also indicate whether the search space is used for only one of the purposes or both. In addition, the signaling for configuring the second search space and the signaling for configuring other search spaces may also be two different signalings, for example, using different fields (IEs) or configured in different RRC messages or system messages.

[0165] In an exemplary embodiment of the present disclosure, the parameters of the second search space are optionally configured. If the base station does not configure the second search space, the UE may use the search space of predefined purpose for the second search space. For example, the search space of predefined purpose may be a search space (RA-searchspace) for receiving random access corresponding to the search space, or a search space (first search space) for monitoring paging control information, or a search space (searchspaceSIB1) for receiving SIB1 system information, or search space 0 (SearchSpace zero). If the base station does not configure the control resource set (CORESET) corresponding to the second search space, the UE may use the CORESET of predefined purpose for the CORESET corresponding to the second search space. For example, the CORESET of predefined purpose may be a CCORESET of Type1-PDCCH CSS for random access, or a Type2-PDCCH CSS for paging, or a CORESET of Type-0 PDCCH CSS.

[0166] In an exemplary embodiment of the present disclosure, if the first type PDSCH in step S102 does not include information about the second search space, the second search space is determined according to a search space for a predefined purpose. For example, the second search space is determined according to the RA-searchspace for random access response indicated in the system information. Further, if the base station configures the second search space for the UE when the UE is in a connected state, and the serving cell of the UE does not change, the UE determines the second search space according to the configured information, and if the serving cell of the UE changes, the UE determines the second search space according to the predefined search space, such as the RA-searchspace.

[0167] In an exemplary embodiment of the present disclosure, the PDCCH in the second search space may be scrambled with the first type of RNTI or scrambled with the RA-RNTI, that is, the RA-RNTI may be determined according to the resources of the PRACH sent in step S103.

[0168] If the base station configures the first type of RNTI, for example, the first type of RNTI is configured through the first type of PDSCH, or the first type of RNTI is configured through UE-specific RRC signaling, or the first type of RNTI is configured through cell system information broadcast, the first type of RNTI can be determined according to the configuration of the base station. When the base station configures the first type of RNTI through multiple signalings, the first type of RNTI can be determined according to one of the signalings according to a predefined priority rule, or the first type of RNTI can be determined in combination with multiple signalings.

[0169] In addition, the first type of RNTI information and other information (such as PRACH information or PaingUE-Identity) included in the first type of PDSCH may be combined to jointly determine the first type of RNTI.

[0170] Here, the parameters of the first type of RNTI can be optionally configured. If the base station is not configured with the first type of RNTI, the first type of RNTI can be determined by the C-RNTI allocated the last time the UE was in the RRC connected state. Alternatively, the first type of RNTI can be determined by PaingUE-Identity, for example, the first type of RNTI is determined according to NG-5G-S-TMSI, or I-RNTI-Value, or ShortI-RNTI-Value and a predefined function. Alternatively, the first type of RNTI can be determined by RA-RNTI. Alternatively, the first type of RNTI is jointly determined by PaingUE-Identity and PRACH resources.

[0171] Here, the validity period of the first type RNTI is configurable. For example, after a predefined time period has passed since the first type RNTI information is received, the RNTI becomes invalid. For another example, before the UE receives the first type RNTI information again, the last first type RNTI remains valid.

[0172] In an exemplary embodiment of the present disclosure, the PDCCH in the second search space may include scheduling information of the PDSCH, for example, resource information of the PDSCH, HARQ information, etc.

[0173] In an exemplary embodiment of the present disclosure, the PDCCH in the second search space may include uplink timing adjustment information (Timing advance).

[0174] In an exemplary embodiment of the present disclosure, the PDCCH in the second search space may include uplink channel information of ACK feedback, such as PUCCH, PRACH or PUSCH information.

[0175] In an exemplary embodiment of the present disclosure, the PDCCH in the second search space may include the first type of RNTI information. At this time, the first type of RNTI may be jointly determined based on the first type of RNTI information included in the PDCCH in the second search space and other information (such as PRACH information or PaingUE-Identity).

[0176] In an exemplary embodiment of the present disclosure, the PDCCH in the second search space may include an indication of UE behavior. Specifically, the PDCCH may trigger the UE to send a PRACH, or the PDCCH may instruct the UE to receive a PDSCH. Among them, the PDCCH may indicate a dedicated PRACH resource, for example, the ra-PreambleIndex indicated in the PDCCH is a non-zero value, or the PDCCH may instruct the UE to select a PRACH resource from a PRACH set according to a predefined rule (for example, when the ra-PreambleIndex indicated in the PDCCH is zero), and the UE performs a contention-based random access process. In addition, the PDCCH may also instruct the UE to send HARQ-ACK via PRACH or PUCCH. In addition, different indication contents are distinguished by a separate bit field in the DCI of the PDCCH, or different indication contents are distinguished by a specific bit value / value combination in the DCI of the PDCCH, or different indication contents are distinguished by scrambling the PDCCH CRC by different RNTIs, or different DCI formats are used to distinguish, or different search spaces are used to distinguish. For example, a PDCCH for determining uplink timing is located in the second search space, and a PDCCH for scheduling a PDSCH carrying data is located in search space C.

[0177] In an exemplary embodiment of the present disclosure, if the UE does not receive a corresponding downlink response in the second search space within the time window T2 (or timer T2) after sending the PRACH, the UE may fall back to the contention-based random access procedure. Here, the PRACH resources used for the contention-based random access procedure used for downlink transmission in the RRC idle / non-connected state and the PRACH resources used for establishing the RRC connection may be configured separately.

[0178] In addition, if the UE does not receive a corresponding downlink response in the second search space within the time window T1 (or timer T1) after sending the PRACH, the UE may send the dedicated PRACH again. And so on. If the number of times the UE sends the PRACH has reached the predefined maximum number of times, the UE cannot try to send this PRACH again.

[0179] In step S105, a second type of PDSCH is received according to the PDCCH received in the second search space.

[0180] In an exemplary embodiment of the present disclosure, the resources of the second type of PDSCH are determined based on the resource information of the PDSCH contained in the PDCCH, the resource information of the PDSCH contained in the first type of PDSCH, or at least one set of PDSCH resource information configured by the base station in the RRC connection state, or the resources of the second type of PDSCH are determined based on the PRACH.

[0181] In an exemplary embodiment of the present disclosure, the second type of PDSCH includes at least one of the following: downlink data, uplink channel information for carrying ACK, uplink timing adjustment information, uplink scheduling information, downlink control information, and the first type of RNTI. Here, the second type of PDSCH is scrambled according to the first type of RNTI, and / or RA-RNTI, and / or cell ID, and / or a sequence determined by PRACH.

[0182] In an exemplary embodiment of the present disclosure, after receiving the second type of PDSCH, the downlink transmission method may further include: monitoring the PDCCH in the second search space within a predetermined time window. Here, the predetermined time window starts from any one of the following: the end symbol of the uplink channel for ACK feedback by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the uplink channel for ACK feedback by the user equipment is located, the end symbol of the PDSCH sent by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the PDSCH sent by the user equipment is located, the end symbol of the PUSCH sent by the user equipment, and the end position of the time slot / sub-time slot where the end symbol of the PUSCH sent by the user equipment is located.

[0183] In an exemplary embodiment of the present disclosure, within a predetermined time window, the UE may receive at least one of the following items sent by the base station: downlink control channel resource configuration information, PRACH configuration information, uplink channel configuration information of ACK feedback, scheduling information of the second type of PDSCH, scheduling information of PUSCH, transmission mode indication information, PRACH transmission trigger information, trigger information of a contention-based random access process, and indication information for entering a sleep state.

[0184] In an exemplary embodiment of the present disclosure, when no PDCCH is received within a predetermined time window or when indication information for entering a sleep state is received, the UE may enter a sleep state.

[0185] The UE may receive the second type of PDSCH according to the PDCCH received in step S104. Alternatively, the UE may receive the second type of PDSCH according to the indication information (or indication) included in the first type of PDSCH in step S102. Alternatively, the UE may receive the second type of PDSCH according to a set of PDSCHs configured by the base station in the RRC connection state (the UE does not release the PDSCH resource information when releasing the RRC connection).

[0186] In an exemplary embodiment of the present disclosure, the UE may determine resources of the second type PDSCH according to the configuration of the PDCCH, the first type PDSCH, or the RRC connection state.

[0187] In addition, the UE may also determine one or more second-type PDSCH resources according to the configuration of the PDCCH, or the first-type PDSCH, or the RRC connection state. For example, similar to the DL SPS in the connection state, the second-type PDSCH resources appear periodically. The base station also configures the number L of second-type PDSCH resources. Then, the UE may attempt to receive PDSCH on L consecutive second-type PDSCH resources.

[0188] If the base station includes a set of PDSCH resource information in the first type of PDSCH, the UE can receive PDSCH according to the PDSCH resources indicated by the included PDSCH resource information. If the base station configures multiple sets of PDSCH resource information for the UE when the UE is in an RRC connected state, it at least includes the time-frequency resources of the PDSCH, the information of the transport block TB carried by the PDSCH (such as MCS information), the reference symbol information, and the corresponding SS / PBCH information. For one SS / PBCH, there is only one set of PDSCH resource information. The UE can determine a set of PDSCH resources corresponding to the SS / PBCH index number i according to the index number i of the SS / PBCH corresponding to the received first type of PDSCH. The UE can receive PDSCH according to this set of PDSCH resources. If the base station configures a set of PDSCH resource information for the UE when the UE is in an RRC connected state, the UE can receive PDSCH according to this set of PDSCH resources.

[0189] In an exemplary embodiment of the present disclosure, the UE may determine the resource information of the PDSCH according to the PRACH sent in step S103. That is, the PRACH resources and the PDSCH resources satisfy a predefined relationship.

[0190] If the PDCCH received by the UE in step S104 indicates the spatial characteristics of the second type of PDSCH, the second type of PDSCH may be received according to the indicated spatial characteristics. If there is no indication, the second type of PDSCH may be received according to the spatial characteristics of the received PDCCH, or the second type of PDSCH may be received according to the spatial characteristics of the received first type of PDSCH.

[0191] In an exemplary embodiment of the present disclosure, the second type PDSCH received by the UE in step S106 and the first type PDSCH received by the UE in step S102 may be QCL.

[0192] Specifically, if the QCL characteristics of the second type of PDSCH are indicated in the first type of PDSCH received in step S102, the UE can receive the PDSCH according to the index number i of the SS / PBCH indicated in the first type of PDSCH and the PDSCH resource information indicated by the base station. If the QCL characteristics of the second type of PDSCH are not indicated in the first type of PDSCH, the UE can receive the second type of PDSCH according to the spatial characteristics of the first type of PDSCH, that is, the first type of PDSCH and the second type of PDSCH are considered to be QCL.

[0193] In an exemplary embodiment of the present disclosure, the second type PDSCH may include downlink data.

[0194] In an exemplary embodiment of the present disclosure, the second-type PDSCH may include uplink channel information for ACK feedback.

[0195] In an exemplary embodiment of the present disclosure, the second type PDSCH may include uplink timing adjustment information (Timing advance).

[0196] In an exemplary embodiment of the present disclosure, the second type of PDSCH may include uplink scheduling information (UL grant). For example, the UE determines the PUSCH resource for carrying the ACK feedback of the second type of PDSCH based on the UL grant information. In this case, the UE does not need to send HARQ-ACK on the PUCCH or PRACH. The base station determines whether the second type of PDSCH is correctly demodulated by receiving the PUSCH sent by the UE.

[0197] In an exemplary embodiment of the present disclosure, the second type of PDSCH may include downlink control information. The downlink control information indicates resource information of the third type of PDSCH. Among them, the third type of PDSCH contains downlink data. For example, the second type of PDSCH is a RAR PDSCH, wherein the downlink control information for scheduling the third type of PDSCH is included in the MAC RAR. Unlike ordinary downlink scheduling, the time delay between the second type of PDSCH and the third type of PDSCH scheduled by the downlink control information in the second type of PDSCH is often larger. Because ordinary downlink scheduling is PDCCH scheduling PDSCH, and here it is PDSCH scheduling PDSCH. Since the processing delay of UE demodulating PDSCH is greater than the processing delay of demodulating PDCCH, and the UE also needs to demodulate MAC RAR to obtain downlink control information, the processing delay is further increased. In order to distinguish these two types of downlink scheduling, it is reasonable to define the time difference from downlink control information to PDSCH separately. For example, when the base station is not configured with a PDSCH time domain resource allocation table, a standard predefined table is used to determine the PDSCH time resource, wherein the time slot parameter K0 is used to indicate the time slot where the PDSCH is located. This value is applicable to the PDSCH scheduled by the PDCCH. In addition, the time slot where the third type of PDSCH is located is determined based on the parameter K0 and the additional time slot delay Δ. Assuming that the time slot where the end symbol of the second type of PDSCH containing the downlink control information is located is time slot n, then the time slot where the third type of PDSCH is located is time slot n+K0+Δ. Optionally, the value of Δ is predefined by the standard. Optionally, the value of Δ is related to the subcarrier spacing. Optionally, the value of Δ is related to the UE type, for example, Δ for UEs with lower and higher processing capabilities are defined separately. Optionally, the value of Δ is related to the synchronization signal broadcast channel block (SS / PBCH Block) and the CORESET multiplexing pattern.

[0198] When the MAC RAR in the second type of PDSCH includes downlink control information for scheduling the third type of PDSCH, the downlink control information includes at least one of the following information: time resources, frequency domain resources, modulation and coding, mapping of virtual RBs to physical RBs, HARQ-ACK feedback delay K1, and PUCCH resources. Optionally, to reduce the downlink control information overhead, the modulation and coding bit field has fewer bits than the modulation and coding bit field in the PDCCH that schedules the PDSCH. For example, the standard predefines 4 MCSs for the third type of PDSCH scheduled by the second type of PDSCH, then the modulation and coding bit field in the second type of PDSCH only requires 2 bits.

[0199] Optionally, whether the MAC RAR in the second type of PDSCH contains downlink control information is indicated by a specific bit in the MAC RAR. As shown in Table 1, the first bit in the MAC RAR indicates whether the MAC RAR contains downlink control information (DL grant) or uplink scheduling information (UL grant), and the Timing Advance Command refers to the uplink timing command, which can be referred to as TAC. Optionally, the number of bits of the DL grant is the same as that of the UL grant, thereby avoiding changing the size of the MAC RAR. For another example, a specific bit in the MAC RAR indicates whether the MAC RAR contains a DL grant, or a DL grant and a UL grant, or whether the MAC RAR contains a DL grant, or a DL grant and a UL grant, or a UL grant. Optionally, the above information is indicated by the subheader of the MAC sPDU. Optionally, the above information is jointly indicated by the subheader of the MAC sPDU and the specific bits in the MAC RAR. Optionally, whether the MAC RAR in the second type of PDSCH contains downlink control information is indicated by the first type of PDSCH. For example, the indication is displayed in the first type PDSCH, or the indication is implicitly indicated through the PRACH resources in the first type PDSCH.

[0200]

[0201] Table 1

[0202] In an exemplary embodiment of the present disclosure, the second type PDSCH may indicate the first type RNTI. The first type RNTI may be explicitly indicated by a bit in the PDSCH, or determined implicitly according to a resource pattern of the PDSCH, or indicated in a combination of explicit and implicit ways.

[0203] In an exemplary embodiment of the present disclosure, the second-class PDSCH indicates a TC-RNTI, and the UE uses the TC-RNTI as the first-class RNTI for the next RRC idle / inactive downlink transmission, for example, for PDCCH scrambling for scheduling downlink data retransmission, for scrambling of the PDSCH carrying downlink data. For example, the PDCCH scheduling the second-class PDSCH is scrambled by the RA-RNTI, and the second-class PDSCH is a RAR PDSCH, including a MAC RAR. The UE uses the TC-RNTI in its own MAC RAR as the first-class RNTI for the next RRC idle / inactive downlink transmission, and considers that the random access process is completed.

[0204] Through the above two methods, the base station does not need to carry the first type of RNTI in the first type of PDSCH, thereby saving the overhead of the paging message.

[0205] In an exemplary embodiment of the present disclosure, the second type of PDSCH may be scrambled according to the first type of RNTI, or RA-RNTI, and / or cell ID, or may be scrambled according to a sequence determined by the PRACH sent in step S103, for example, a sequence is determined based on the time, frequency domain, codeword information, etc. of the PRACH.

[0206] When the second type of PDSCH is scrambled according to RA-RNTI, or when the PDCCH that schedules the second type of PDSCH is scrambled according to RA-RNTI, the UE needs to find the content corresponding to the UE in the second type of PDSCH, for example, the downlink data of the UE, and / or the downlink control information of the third type of PDSCH that schedules the UE, the time advance indication (TA Commond), the TC-RNTI, etc. The UE can find the starting position of the corresponding subPDU according to the size of one or more subPDUs of the medium access control protocol data unit MAC PDU (Medium Access Control Protocal Data units), and read the MAC subheader (subheader) and MAC RAR therefrom to determine whether a subPDU belongs to the UE, and the content of the MAC RAR in the subPDU belonging to the UE. The UE determines whether the MAC subPDU belongs to the UE according to the indication in the subheader of the MAC subPDU, for example, whether the random access preamble ID (RAPID) in the subheader is the same as the PRACH Preamble ID sent by the UE. If they are the same, the MAC RAR in the MAC subPDU is read to obtain downlink data, and / or downlink control information, time advance indication (TA Commond), TC-RNTI, etc. In the prior art, the size of the MAC RAR is fixed, but when the MAC RAR carries downlink data or downlink control information, the size of the MAC RAR may be multiple, and a new method is needed to enable the UE to determine the size of each subPDU detected, thereby determining the starting point of the current and subsequent subPDUs. The UE determines the size of the subPDU and the content in the subPDU according to one of the methods described below:

[0207] Method 1: Determine the MAC RAR size of the UE according to the indication in the MAC subheader of the Medium Access Control Protocol Data Units (MAC PDU).

[0208] A specific bit field in the MAC subheader is used to indicate whether the MAC RAR in this MAC subPDU contains data or downlink control information, thereby determining the size of this MAC subPDU.

[0209] Furthermore, the size of the data contained in the RAR can be indicated by a specific bit field in the MAC subheader to determine the size of the MAC subPDU. The standard predefines one or more data sizes, and a specific bit field indicates one of the sizes. As shown in Table 2, the subheader length L2 = 16 bits, of which the 9th to 10th bits can indicate four RAR sizes, 56 (excluding data), X1, X2 and X3. Alternatively, the RAR can contain a DL grant, or a DL grant and a UL grant, according to a specific bit field in the MAC subheader.

[0210]

[0211] Table 2

[0212] Optionally, the size L2 of the MAC subheader is different from the size L1 of the MAC subheader of the UE that does not support MT-EDT transmission. For example, the length of the MAC subheader of a lower version UE or a UE that does not support MT-EDT transmission is L1=8 bits, and the length of the MAC subheader of a UE that supports MT-EDT transmission or a UE that supports MT-EDT transmission that carries data in the second type of PDSCH RAR is L2=16 bits. Optionally, the base station may configure the UE to receive the MAC subheader according to L1 or L2, for example, the base station configures when the UE is in an RRC connected state, or indicates in the first type of PDSCH, or by indicating in the PDCCH that schedules the second type of PDSCH, or by indicating in the random access preamble ID bit field (RAPID) in the L1 bit before the subheader. Different subheader lengths correspond to different preamble ID sets.

[0213] Optionally, the base station only places the RAR of UEs with the same subheader length in the same second-class PDSCH. The base station can indicate the length of the subheader in the PDCCH that schedules the second-class PDSCH. Furthermore, the base station can indicate the length of the subheader by a specific bit field in the PDCCH that schedules the second-class PDSCH, or by sending PDCCHs for second-class PDSCHs with different subheader lengths in different search spaces, or by using different RNTI scrambling methods for PDCCHs for second-class PDSCHs with different subheader lengths, so as to avoid affecting lower-version UEs.

[0214] Optionally, the base station can place the RARs of UEs with different subheader lengths in the same second-class PDSCH. To avoid affecting lower-version UEs, the base station places the MAC subPDU of the UE with a subheader length of L1=8 in the first half of the MAC PDU, and places the MAC subPDU of the UE with a subheader length of L2=16 in the second half of the MAC PDU. Furthermore, the UE with a subheader length of L2=16 and the UE with a subheader length of L1=8 interpret the specific bit fields in the first 8 bits of the subheader differently. For example, when a UE with a subheader length of L1=8 reads a subheader (this subheader may or may not belong to the UE), when the value of the first bit field E (Extention field) is 0, the UE considers that the MAC subPDU including this subheader is the last MAC subPDU of the current MAC PDU, otherwise, there are other MAC subPDUs following the MAC subPDU including this subheader. When a UE with a subheader length of L2=16 reads a subheader (this subheader does not belong to the UE), when the value of the first bit field E is 0, the UE considers that the MAC subPDU including this subheader is the last MAC subPDU with a subheader length of L1=8 of the current MAC PDU, otherwise, there are other MAC subPDUs with a subheader length of L1=8 following the MAC subPDU including this subheader. For a UE with a subheader length of L2=16, when the value of the bit field E read is 0, the UE may assume that if the MAC PDU contains other MAC subPDUs, the subheader length of these MAC subPDUs is L2=16. For a UE with a subheader length of L2=16, it is possible to determine whether the MACsubPDU is the last MAC subPDU in the MAC PDU based on the bit field E in the subheader of L2=16, and determine the RAR size based on the specific bit field of the subheader.

[0215] Optionally, the size of the MAC subheader is the same as the size of the MAC subheader of the UE that does not support MT-EDT transmission. The RAPID in the MAC subheader is used to determine whether the MAC RAR contains data, or to determine the size of the data in the MAC RAR. For example, whether data is contained corresponds to different preamble ID sets. To avoid confusion, the base station places the MAC subPDU of the UE whose MAC RAR does not contain data in the first half of the MAC PDU, and places the MAC subPDU of the UE whose MAC RAR contains data in the second half of the MAC PDU. Similarly, if the UE has learned that its MAC RAR contains data, for example, determined by the Preambele ID assigned by the base station, when the UE reads the value of the first bit field E of the subheader of the MAC subPDU that does not contain data in the MAC RAR as 0, the UE considers that the MAC subPDU including this subheader is the last MAC subPDU that does not contain data in the current MAC PDU, otherwise, there are other MAC subPDUs that do not contain data after the MAC subPDU including this subheader.

[0216] Method 2: Determine the MAC RAR size of the UE according to the indication in the MAC RAR in the MAC subPDU in the Medium Access Control Protocol Data Units (MAC PDU).

[0217] The specific bit field in the MAC RAR payload is used to indicate whether the RAR contains data or whether it contains DL grant. As shown in Table 3, according to the first reserved bit R of the MAC RAR payload, it is indicated whether data is contained in the RAR. Optionally, the size of the data contained in the RAR can be indicated according to the specific bit field of the MAC RAR payload. For example, the specific bit field in the MAC RAR payload indicates the size of the data. The standard predefines one or more data sizes, and the DL-SCH bit field indicates one of the sizes. Alternatively, according to the first reserved bit R of the MAC RAR payload, it is indicated that the RAR contains DL grant or DL ​​grant and UL grant.

[0218]

[0219] Table 3

[0220] Similar to method one, optionally, to avoid affecting lower version UEs, the base station only places the RAR of UEs with the same MAC RAR length in the same second-type PDSCH. The base station can indicate the RAR length in the PDCCH that schedules the second-type PDSCH. Furthermore, the base station can indicate the length of the RAR by a specific bit field in the PDCCH that schedules the second-type PDSCH, or by sending the PDCCH of the second-type PDSCH of the two types of UEs in different search spaces, or by using different RNTI scrambling methods for the PDCCH of the second-type PDSCH of the two types of UEs, to avoid affecting lower version UEs.

[0221] Optionally, the base station can place the RARs of UEs with different RAR lengths in the same second-class PDSCH. To avoid affecting lower-version UEs, the MAC subPDU of UEs that are not configured to possibly receive data in the RAR is placed in the first half of the MAC PDU, and the MAC subPDU of UEs that are configured to possibly receive data in the RAR is placed in the second half of the MAC PDU. Similarly, these two types of UEs interpret specific bit fields in the first 8 bits of the subheader differently. For example, when a UE that is not configured to possibly receive data in the RAR reads a subheader (this subheader may or may not belong to the UE), when the value of the first bit field E (Extention field) is 0, the UE considers that the MAC subPDU including this subheader is the last MAC subPDU of the current MAC PDU, otherwise, there are other MAC subPDUs following the MACsubPDU including this subheader. When a UE configured to possibly receive data in a RAR reads a subheader (this subheader does not belong to the UE), and the value of the first bit field E is 0, the UE considers that the MAC subPDU including this subheader is the last MAC subPDU of the current MAC PDU that is not configured to possibly receive data in the RAR for the UE, otherwise, the MAC subPDU including this subheader is followed by other MAC subPDUs of UEs that are not configured to possibly receive data in the RAR. For a UE configured to possibly receive data in a RAR, it can be determined whether the MAC subPDU is the last MAC subPDU in the MAC PDU based on the bit field E in the subheader, and the RAR size can be determined based on the specific bit field in the RAR.

[0222] The method for determining the start point and size of a MAC subPDU described above is not only applicable to the MT-EDT transmission process, but is also widely applicable to other transmission processes that require determining the start point and size of a MAC subPDU.

[0223] In an exemplary embodiment of the present disclosure, when sending the second type of PDSCH, the base station may also send downlink control information together. For example, the downlink control information is sent on a predefined resource within the time-frequency resource of the second type of PDSCH to indicate the HARQ information of the second type of PDSCH, such as retransmission or new transmission, HARQ ID, etc. The downlink control information is independently encoded with the second type of PDSCH.

[0224] Here, the second type of PDSCH may be Msg 2 or Msg B in the random access process. Msg 2 or Msg B may include at least one of the various information and data described above. The second type of PDSCH may also be a PDSCH dedicated to carrying downlink data. For example, the PDCCH that schedules the second type of PDSCH and the second type of PDSCH are both scrambled according to the first type of RNTI and are UE-specific PDCCH and PDSCH.

[0225] In step S106, the second type PDSCH is demodulated, and ACK feedback is performed according to the demodulation result. Here, the ACK feedback may be HARQ-ACK feedback or higher layer ACK feedback.

[0226] In an exemplary embodiment of the present disclosure, a fallback to a contention-based random access procedure may be performed based on a received fallback indication or based on a detected fallback trigger condition. Here, the fallback trigger condition includes at least one of the following: uplink timing failure, receiving a PDCCH scheduling a second type of PDSCH but uplink timing failure, and not receiving a response within a predefined time window after a contention-free PRACH is sent.

[0227] If the UE demodulates the PDSCH correctly, the UE feeds back an ACK, and if the UE does not demodulate the PDSCH correctly, the UE does not feed back an ACK. Alternatively, the UE may feed back an ACK or a NACK according to the demodulation result of the PDSCH.

[0228] In an exemplary embodiment of the present disclosure, HARQ-ACK may be carried by PRACH. The base station configures dedicated PRACH resources for the UE, for example, the dedicated PRACH resources configured by the base station for the UE when the UE is in an RRC connected state (the UE does not release the PRACH resource information when releasing the RRC connection), or the base station configures PRACH resources for the first type of PDSCH in step S102, or the PDCCH in step S104, or the second type of PDSCH in step S105. Here, the PRACH resources do not belong to the cell common PRACH resource set indicated in the system information (e.g., SIB1), or belong to the cell common PRACH resources. Alternatively, the base station may configure in the system information a set of PRACH resources dedicated to carrying HARQ-ACK during downlink transmission when the UE is in the RRC idle / deactivated state, and the UE may select a PRACH resource from the set according to a predefined rule, for example, determine the PRACH resource according to the received PDCCH resource and / or PDSCH resource, or the base station may indicate one of the PRACH resources in the PDCCH in step S101, or the first type of PDSCH in step S102, or the PDCCH in step S104, or the second type of PDSCH in step S105. In an exemplary embodiment of the present disclosure, for example, if the UE correctly demodulates the PDSCH, the UE may send the PRACH; if the UE does not correctly demodulate the PDSCH, the UE may not send the PRACH. For example, if the UE correctly demodulates the PDSCH, the UE may send PRACH 1; if the UE does not correctly demodulate the PDSCH, the UE may send PRACH 2. In a special implementation manner, the resources of PRACH1 and PRACH2 are the same, but the phases are different. For example, PRACH1 is multiplied by -1 to obtain PRACH2.

[0229] In an exemplary embodiment of the present disclosure, HARQ-ACK may be carried by PUCCH. Here, PUCCH resources may be optionally configured. The base station may configure dedicated PUCCH resources for the UE, where the PUCCH resources are dedicated to the UE during downlink transmission when the UE is in the RRC idle / deactivated state. For example, the base station configures PUCCH resources for the UE in the RRC idle / deactivated state and the PUCCH resources for the UE in the RRC connected state, respectively. Alternatively, the base station may configure a set of PUCCH resources for both the RRC idle / deactivated state and the RRC connected state. If the base station does not configure UE-specific PUCCH resources, the standard predefined PUCCH resource set and the PUCCH resources determined by the indication in the system information may be used for the UE during downlink transmission when the UE is in the RRC idle / deactivated state. For example, when the UE is in the RRC connected state, the base station configures one or more PUCCH resources for the UE, which are dedicated to the UE during downlink transmission when the UE is in the RRC idle / deactivated state. The UE does not release the PUCCH resource information when releasing the RRC connection. The base station indicates one PUCCH resource among the configured one or more PUCCH resources through the first type PDSCH in step S102, or the PDCCH in step S104, or the second type PDSCH in step S105. For another example, if the standard predefines one or more groups of PUCCH resources, the base station may indicate one group of the one or more groups of PUCCH resources in the system information (e.g., pucch-ResourceCommon), and the base station may indicate one PUCCH resource among the group of PUCCH resources through the first type PDSCH in step S102, or the PDCCH in step S104, or the second type PDSCH in step S105.

[0230] Here, the signaling for PUCCH or PRACH and the signaling for configuring PUCCH or PRACH resources in RRC connected state can be the same, and the base station will also indicate whether the resource is used for only one of the purposes or both. In addition, the configuration signaling can also be two different signalings, for example, using different fields (IE) or configured in different RRC messages or system messages.

[0231] PUCCH resources include one or more of the following: PUCCH format, frequency domain resources of PUCCH, time domain resources of PUCCH, codeword resources of PUCCH, spatial characteristics of PUCCH (for example, which reference signal QCL of which cell), set of HARQ-ACK feedback delay K1, PUCCH power control information, maximum code rate of PUCCH, cyclic prefix of PUCCH, etc. Here, in PUCCH power control, the closed-loop power control parameters may not be accumulated with the closed-loop power control parameters in the RRC connected state, that is, the closed-loop power control parameters of the first PUCCH transmission when the UE is in the RRC idle / deactivated state are reset to 0, and accumulated according to the closed-loop power control parameters of the PDCCH when the UE is in the RRC idle / deactivated state.

[0232] In an exemplary embodiment of the present disclosure, it can be determined whether to use PUCCH or PRACH to send HARQ-ACK according to the indication of the first type of PDSCH in step S102, or the PDCCH in step S104, or the second type of PDSCH in step S105. The base station can configure the UE to use PUCCH or PRACH to send HARQ-ACK. For example, when the UE is in an RRC connected state, the base station can indicate the uplink channel of sending HARQ-ACK when the UE is in an RRC idle / deactivated state through high-layer signaling. The UE can determine whether to use PUCCH or PRACH to send HARQ-ACK according to whether the uplink timing is valid. When the uplink timing maintained by the UE fails, the UE can only send PRACH. The time resource of the PRACH resource may not be earlier than the PDSCH time resource in step S105. The time difference between the time resource of the PRACH resource and the PDSCH time resource in step S105 may not be less than the predefined delay. For example, the UE receives the PDSCH in step S105 and sends the PRACH on the first available PRACH resource after the PDSCH. Depending on the decoding result of the PDSCH, the time and / or frequency domain and / or codeword resources of the PRACH may be different. The time resources of the PRACH resources may not be earlier than the time resources of the uplink channel used to send HARQ-ACK in step S106 indicated by the PDCCH in step S104. The time resources of the PRACH resources may not be earlier than the time resources of the PUCCH used to send HARQ-ACK in step S106 indicated by the PDCCH in step S104. The time resources of the PRACH resources may not be earlier than the time resources of the PDCCH in step S101. For example, after receiving the PDCCH in step S104, the UE immediately attempts to send PRACH on the available PRACH resources without attempting to receive the PDSCH scheduled by the PDCCH.

[0233] In an exemplary embodiment of the present disclosure, a high-level ACK may be carried by PUSCH. The resources of PUSCH are indicated by the second-type PDSCH, or the PDCCH that schedules the second-type PDSCH, or the first-type PDSCH. If the UE demodulates the PDSCH correctly, the UE feeds back ACK via PUSCH. If the UE does not demodulate the PDSCH correctly, the UE does not send PUSCH.

[0234] If the base station does not support the UE's spontaneous transmission of PRACH during downlink transmission when the RRC is idle / deactivated, the UE sends PUCCH to carry HARQ-ACK when the UE's uplink timing is valid, and does not send PUCCH when the UE's uplink timing is invalid, that is, DTX. One implementation method is that when the base station does not detect the PUCCH from the UE, the base station can send PDCCH to trigger the UE to send PRACH. When the UE receives a PDCCH triggering PRACH transmission, if the PDCCH indicates a contention-free PRACH transmission, for example, the ra-PreambleIndex indicated in the PDCCH is a non-zero value, the UE performs contention-free PRACH transmission. For a detailed description, see Figure 1 If the PDCCH indicates contention-based PRACH transmission, for example, the ra-PreambleIndex indicated in the PDCCH is all zero, the UE falls back to the contention-based random access procedure.

[0235] In an exemplary embodiment of the present disclosure, when the uplink timing of the UE is invalid, the UE does not send the PUCCH. The UE starts the time window T3. If the UE does not receive any instruction from the base station within the time window T3, the UE falls back to the contention-based random access process. The length of the time window T3 is ≥ 0.

[0236] The base station may be configured to send the BWP for the PRACH or PUCCH carrying the HARQ-ACK, or the BWP for sending the PRACH or PUCCH carrying the HARQ-ACK may be an initial BWP, i.e., the UL BWP used for initial random access in the cell where the UE is located, or the UL BWP for sending the PRACH in step S103 may be used to send the PRACH or PUCCH carrying the HARQ-ACK.

[0237] In an exemplary embodiment of the present disclosure, when the uplink timing of the UE is valid, the UE may send a PUCCH or PRACH for carrying HARQ-ACK, or a PUSCH for carrying a higher layer ACK according to the uplink timing.

[0238] When the uplink timing of the UE is invalid, the UE may send an uplink channel for carrying the HARQ-ACK according to the downlink timing, or the UE may not send the HARQ-ACK.

[0239] When the UE has sent a PRACH once and received a downlink response based on the PRACH but has not correctly demodulated the second type of PDSCH, the UE does not increase the power of the PRACH when sending the PRACH for the second time.

[0240] When the UE has sent a PRACH once but has not received a downlink response based on the PRACH, the UE increases the power of the PRACH when sending the PRACH for the second time.

[0241] When the UE has sent a PRACH once but has not received a downlink response based on the PRACH, the UE does not increase the power of the PRACH when sending the PRACH for the second time.

[0242] In an exemplary embodiment of the present disclosure, after step S105 and / or step S106, the UE may continue to monitor the PDCCH. Further, the UE may monitor the PDCCH within a predetermined time window. For example, the UE monitors the PDCCH within the time window T0 after each HARQ-ACK feedback is sent or after a high-level ACK is sent. For another example, the UE monitors the PDCCH within the time window T0 after each PDSCH is received.

[0243] In addition, the UE may monitor the PDCCH in the second search space within a predetermined time window.

[0244] In addition, the UE monitors the PDCCH in other search spaces outside the first search space and the second search space within a predetermined time window. The resources of the second search space and other search spaces outside the first search space and the second search space are configured independently. In addition, if the base station does not configure parameters of other search spaces outside the first search space and the second search space, it can be considered that the other search spaces outside the first search space and the second search space are equal to the second search space.

[0245] Here, the length of the predefined time window may be measured in absolute time, or in the period of the downlink physical control channel search space, or in the number of symbols, or in the time slot / sub-time slot.

[0246] Here, the predefined time window starts at a specific time point. For example, it can be the end symbol of the uplink channel of the last HARQ-ACK sent by the UE as the starting point, or the end position of the time slot / sub-time slot where the end symbol of the uplink channel of the last HARQ-ACK sent by the UE is located, or the end symbol of the uplink channel containing ACK sent by the UE is the starting point, or the end position of the time slot / sub-time slot where the end symbol of the uplink channel containing ACK sent by the UE is located, or the end symbol of the last PDSCH received by the UE is the starting point, or the end position of the time slot / sub-time slot where the end symbol of the last PDSCH received by the UE is located, or the end symbol of the last PUSCH sent by the UE is the starting point, or the end position of the time slot / sub-time slot where the end symbol of the last PUSCH sent by the UE is located, or the starting point is the starting point or the end position of the PDCCH.

[0247] In an exemplary embodiment of the present disclosure, the time window length may be 0, and the starting point of the time window may be the uplink channel end symbol containing ACK sent by the UE. After sending ACK, the UE may immediately enter a sleep state.

[0248] In addition, the predefined time window may be optionally configured, and if the base station does not configure the time window, the UE uses the time window for monitoring the random access response (Random Access Response, RAR) for the predefined time window. If the base station does not configure the time window, the UE may use a default value for the time window.

[0249] In addition, the predefined time window may be configured via UE-specific RRC signaling. Here, the predefined time window may be configured via cell system information broadcast.

[0250] In an exemplary embodiment of the present disclosure, within the time window, the base station may send configuration information of the downlink control channel resources. For example, the base station sends the configuration of the second search space or other search spaces through PDCCH or PDSCH. The configuration information of the downlink control channel resources may take effect after a predefined time delay. For example, after X ms after the UE receives the PDSCH containing the configuration information of the downlink control channel resources, the second search space or other search spaces other than the second search space are determined according to the configuration information of the downlink control channel resources.

[0251] In addition, within the time window, the base station can send configuration information of downlink control channel resources. For example, the base station indicates whether to monitor other types of DCI or other search spaces (other search spaces other than the second search space) through PDCCH or PDSCH.

[0252] In addition, within the time window, the base station may send PRACH configuration information, for example, the base station configures the PRACH format, time-frequency code resources, etc. through PDCCH or PDSCH.

[0253] In addition, within the time window, the base station can send configuration information of the uplink channel carrying HARQ-ACK. For example, the base station sends resource configuration information of PRACH or PUCCH through PDCCH or PDSCH. The resource configuration information takes effect after a predefined time delay. For example, it takes effect X ms after the UE receives the PDSCH containing the resource configuration information, or takes effect in the next second search space or other search space.

[0254] In addition, within the time window, the base station may send a PDCCH including scheduling information of the second PDSCH in the scheduling step, for example, scheduling the retransmission of the PDSCH. Optionally, if the downlink control information for scheduling the initial transmission of the PDSCH does not include a new data indication bit field (NDI), it is assumed that the NDI at the time of the initial transmission is 0, and the UE determines whether the PDSCH scheduled by the PDCCH is a retransmission based on whether the NDI bit field in the subsequently received PDCCH is flipped.

[0255] In this time window, the base station may send a PDCCH to instruct the UE to act. For example, the PDCCH triggers the UE to perform a random access procedure, or the PDCCH instructs the UE to receive a PDSCH.

[0256] In addition, within this time window, the base station can send a PDCCH to trigger the UE to send a specific PRACH. The base station can perform uplink synchronization and other operations based on the received PRACH. The base station can send uplink timing adjustment information in the subsequently sent PDCCH or PDSCH for the uplink timing of the PUCCH for the UE's HARQ-ACK feedback of the PDSCH. This process is similar to the random access process based on PDCCH triggering. In addition, the base station can also carry downlink data in this PDSCH.

[0257] In addition, within this time window, the base station can send PDCCH to trigger the UE to perform a contention-based random access process. Here, PDCCH triggers the UE to perform a contention-based random access process and establish an RRC connection. It is not difficult to see that this is a fallback mechanism. For example, when the base station finds that it cannot detect PUCCH, it may be that the UE did not monitor the PDCCH, but it may also be caused by uplink desynchronization. The base station triggers the UE to send PRACH, regain uplink synchronization, and instructs the UE uplink timing information, so that the UE can send according to reasonable uplink timing in subsequent transmissions.

[0258] In addition, within the time window, the base station may send a PDCCH to schedule the PUSCH to be sent. For example, in this PUSCH, the UE may send a high-level ACK. After correctly receiving this PUSCH, the base station may send another PDCCH to indicate that this PUSCH has been correctly received, such as sending an ACK via DCI, or sending information to instruct the UE to perform a predefined state X via DCI.

[0259] In addition, within the time window, the base station may send a PDCCH to instruct the UE to enter a sleep state.

[0260] In addition, within the time window, the base station can send the PDSCH.

[0261] In step S107, when a predefined condition is met, a predefined state X is entered.

[0262] In an exemplary embodiment of the present disclosure, the predefined state X may indicate that the UE enters a sleep mode. For example, the UE stops monitoring the PDCCH. However, the UE may still need to wake up at some specific time points, for example, waking up at a paging opportunity, or the UE wakes up at a time resource corresponding to the second search space to monitor the PDCCH.

[0263] The predefined condition C1 includes at least one of the following conditions:

[0264] (1) Within a predefined time window, the UE receives a signaling instructing the UE to enter a predefined state X;

[0265] (2) The UE does not receive any PDCCH within the predefined time window;

[0266] (3) Within the predefined time window, the number of PRACH transmissions by the UE has reached the maximum number of transmissions.

[0267] Here, the signaling instructing the UE to enter the predefined state X can be carried by a specific DCI format, and / or a specific bit field, and / or a specific bit value. For example, the DCI indicates that the UE enters a sleep mode, or the DCI indicates that an ACK fed back by the UE is correctly received, or the DCI indicates an ACK for uplink transmission.

[0268] Different time windows are configured for different downlink transmissions or uplink transmissions. When there are multiple time windows, the UE enters state X when the last time window ends. When there are multiple time windows, the UE enters state X when the first time window ends.

[0269] In order to better understand the various solutions of this embodiment, several examples are given below, but the solutions of this embodiment are not limited to these examples. In each step, the specific implementation method will not be repeated, and reference is made to the foregoing description.

[0270] Example 1:

[0271] -The UE receives a PDCCH scheduling a paging message in the first search space in the PO, and receives a paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives PRACH configuration information, a first type RNTI, and UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0272] -UE sends PRACH according to the PRACH configuration information.

[0273] -UE monitors PDCCH in the second search space. The second search space is RA-Searchspace. PDCCH is scrambled by RA-RNTI, and PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources), and uplink timing adjustment information. Alternatively, PDCCH is scrambled by the first type of RNTI, and PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PDSCH, and contains PRI information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0274] o If the UE monitors a PDCCH scrambled by an RA-RNTI or a PDCCH scrambled by a first-type RNTI scheduling a second-type PDSCH in the second search space, the UE receives the second-type PDSCH.

[0275] The UE generates HARQ-ACK based on the demodulation result of the second type of PDSCH. It determines a PUCCH resource based on the PRI of the PDCCH and the PUCCH resource set indicated by the system information and sends the HARQ-ACK. The UE determines the uplink timing of sending the PUCCH based on the uplink timing adjustment information in the PDCCH. The UE monitors the second search space again and starts the time window T0.

[0276] o If the UE monitors the PDCCH scrambled by the first type of RNTI in the second search space and triggers PRACH transmission, the UE sends PRACH, monitors the second search space again, and starts the time window T0.

[0277] o If the UE monitors the PDCCH scheduling the PUSCH in the second search space, the UE sends the PUSCH, monitors the second search space again, and starts the time window T0.

[0278] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0279] Example 2:

[0280] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the PRACH configuration information, the first type RNTI, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0281] -UE sends PRACH according to the PRACH configuration information.

[0282] -UE monitors PDCCH in the second search space. The second search space is RA-Searchspace. PDCCH is scrambled by RA-RNTI, and PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources), and uplink timing adjustment information. Alternatively, PDCCH is scrambled by the first type of RNTI, and PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PDSCH, and contains PRI information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0283] o If the UE does not detect any PDCCH in the second search space within time window T1 after sending PRACH, and the maximum number of PRACH transmissions has not been exceeded, the UE sends PRACH again according to the PRACH resources indicated in the paging message applicable to the UE and starts time window T1 again. If the maximum number of PRACH transmissions has been reached, the UE enters the sleep state.

[0284] o If the UE detects PDCCH in the second search space within the time window T1 after sending PRACH, and PDCCH triggers PRACH transmission, the UE sends PRACH according to the resources indicated by this PDCCH. Similarly, the UE determines the corresponding transmission behavior according to the time window T1 and the number of PRACH transmissions.

[0285] o If, after sending the PRACH, the UE monitors the PDCCH scrambled by the RA-RNTI or the PDCCH scrambled by the first type of RNTI in the second search space within the time window T1, the second type of PDSCH is scheduled, and the UE receives the second type of PDSCH.

[0286] The UE generates HARQ-ACK based on the demodulation result of the second type of PDSCH. And determines a PUCCH resource based on the PRI of the PDCCH and the PUCCH resource set of the system information, and sends the HARQ-ACK. The UE determines the uplink timing of sending the PUCCH based on the uplink timing adjustment information in the PDCCH. The UE monitors the second search space again and starts the time window T0. If the UE does not detect any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to sleep within the time window T0, the UE enters the sleep state in advance.

[0287] o If the UE monitors the PDCCH scheduling PUSCH in the second search space within time window T1 after sending the PRACH, the UE sends the PUSCH, monitors the second search space again, and starts time window T0.

[0288] Example 3:

[0289] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the PRACH configuration information, the first type RNTI, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0290] -UE sends PRACH according to the PRACH configuration information.

[0291] -UE monitors PDCCH in the second search space. The second search space is RA-Searchspace. PDCCH is scrambled by RA-RNTI, PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources). Alternatively, PDCCH is scrambled by the first type of RNTI, and PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PDSCH, and contains PRI information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0292] o If the UE detects in the second search space a PDCCH scrambled by RA-RNTI or a PDCCH scrambled by the first type of RNTI scheduling a second type of PDSCH (the second type of PDSCH contains uplink timing adjustment information), the second type of PDSCH is received.

[0293] If the UE correctly demodulates the second type of PDSCH, the UE generates an ACK, determines a PUCCH resource according to the PRI of the PDCCH and the PUCCH resource set indicated by the system information, and sends the ACK. The UE determines the uplink timing of sending the PUCCH according to the uplink timing adjustment information in the second type of PDSCH. The UE monitors the second search space again and starts the time window T0; if the UE does not correctly demodulate the second type of PDSCH, the UE does not send HARQ-ACK, and the UE monitors the second search space again and starts the time window T0.

[0294] o If the UE monitors the PDCCH scrambled by the first type of RNTI in the second search space and triggers PRACH transmission, the UE sends PRACH, monitors the second search space again, and starts the time window T0.

[0295] o If the UE monitors the PDCCH scheduling the PUSCH in the second search space, the UE sends the PUSCH, monitors the second search space again, and starts the time window T0.

[0296] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0297] Example 4:

[0298] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the PRACH configuration information, the first type RNTI, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0299] -UE sends PRACH according to the PRACH configuration information.

[0300] -UE monitors PDCCH in the second search space. The second search space is RA-Searchspace. PDCCH is scrambled by RA-RNTI, and PDCCH contains PDSCH scheduling information. Alternatively, PDCCH is scrambled by the first type of RNTI, and PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PDSCH, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0301] o If the UE detects in the second search space that the RA-RNTI-scrambled PDCCH schedules the second type of PDSCH, the UE receives the second type of PDSCH, wherein the second type of PDSCH includes uplink timing adjustment information, uplink scheduling information UL grant, and downlink data.

[0302] If the UE demodulates the second type of PDSCH correctly, the UE sends a PUSCH including a high-level ACK according to the UL grant in the second type of PDSCH. The UE determines the uplink timing of sending the PUSCH according to the uplink timing adjustment information in the second type of PDSCH. The UE monitors the second search space again and starts the time window T0; if the UE does not demodulate the second type of PDSCH correctly, the UE does not send an uplink signal, and the UE monitors the second search space again and starts the time window T0.

[0303] o If the UE monitors the PDCCH scrambled by the first type of RNTI in the second search space and triggers PRACH transmission, the UE sends PRACH, monitors the second search space again, and starts the time window T0.

[0304] o If the UE monitors a PDCCH scrambled by the first type of RNTI in the second search space and schedules PDSCH reception or PUSCH transmission, the UE receives the PDSCH and sends HARQ-ACK or sends PUSCH, monitors the second search space again, and starts the time window T0.

[0305] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0306] Example 5:

[0307] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the PRACH configuration information, the first type RNTI, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0308] -UE sends PRACH according to the PRACH configuration information.

[0309] -UE monitors PDCCH in the second search space. The second search space is RA-Searchspace. PDCCH is scrambled by RA-RNTI, PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources). Alternatively, PDCCH is scrambled by the first type of RNTI, and PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PDSCH, and contains PRI information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0310] o If the UE does not detect any PDCCH within time window T1 after sending PRACH, and the maximum number of PRACH transmissions has not been exceeded, the UE sends PRACH again according to the PRACH resources indicated in the paging message applicable to the UE and starts time window T1 again. If the maximum number of PRACH transmissions has been reached, the UE enters the sleep state.

[0311] o If the UE detects PDCCH within time window T1 after sending PRACH, and PDCCH triggers PRACH transmission, the UE can choose to send PRACH according to the resources indicated by this PDCCH. Similarly, the UE determines the corresponding transmission behavior based on time window T1 and the number of PRACH transmissions.

[0312] oIf, after sending PRACH, the UE monitors the PDCCH scrambled by RA-RNTI or the PDCCH scrambled by the first type of RNTI within the time window T1, and schedules the second type of PDSCH (the second type of PDSCH contains uplink timing adjustment information), the UE receives the second type of PDSCH.

[0313] If the UE correctly demodulates the second type of PDSCH, the UE generates an ACK, determines a PUCCH resource according to the PRI of the PDCCH and the PUCCH resource set indicated by the system information, and sends the ACK. The UE determines the uplink timing of sending the PUCCH according to the uplink timing adjustment information in the second type of PDSCH. The UE monitors the second search space again and starts the time window T0; if the UE does not correctly demodulate the second type of PDSCH, the UE does not send HARQ-ACK, and the UE monitors the second search space again and starts the time window T0.

[0314] o If the UE monitors the PDCCH scheduling PUSCH within the time window after sending the PRACH, the UE sends the PUSCH and monitors the second search space again, and starts the time window T0.

[0315] oIf the UE does not monitor any PDCCH within the time window after sending PRACH, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0316] Example 6:

[0317] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the PRACH configuration information, the first type RNTI, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0318] -UE sends PRACH according to the PRACH configuration information.

[0319] -UE monitors PDCCH in the second search space. The second search space is RA-Searchspace. PDCCH is scrambled by RA-RNTI, PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources). Alternatively, PDCCH is scrambled by the first type of RNTI, and PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PDSCH, and contains PRI information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0320] o If the UE monitors a PDCCH scrambled by RA-RNTI or a PDCCH scrambled by the first type of RNTI in the second search space, and schedules a second type of PDSCH (the second type of PDSCH contains uplink timing adjustment information), the UE receives the PDSCH.

[0321] If the UE demodulates the second type of PDSCH correctly, the UE generates an ACK, determines a PUCCH resource according to the PRI of the PDCCH and the PUCCH resource set indicated by the system information, and sends the ACK. The UE determines the uplink timing for sending the PUCCH according to the uplink timing adjustment information in the second type of PDSCH. The UE monitors the second search space again and starts the time window T0; if the UE does not demodulate the second type of PDSCH correctly, the UE sends the PRACH. The UE determines the sending time of the PRACH according to the downlink timing. The UE monitors the second search space again and starts the time window T0.

[0322] o If the UE monitors the PDCCH scrambled by the first type of RNTI in the second search space and triggers PRACH transmission, the UE sends PRACH, monitors the second search space again, and starts the time window T0.

[0323] o If the UE monitors the PDCCH scheduling the PUSCH in the second search space, the UE sends the PUSCH, monitors the second search space again, and starts the time window T0.

[0324] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0325] Example 7:

[0326] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the first type RNTI, the second search space configuration information, the PRACH resource, the scheduling information of the second type PDSCH, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0327] -The UE receives the second type PDSCH according to the paging message of the UE.

[0328] -UE generates HARQ-ACK based on the demodulation result of the second type of PDSCH and sends it through PRACH (for example, ACK uses PRACH sequence 1 and NACK uses PRACH sequence 2). UE sends PRACH according to downlink timing. UE monitors the second search space and starts time window T0.

[0329] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0330] oIf the UE monitors PDCCH within time window T0, PDCCH schedules PDSCH, and PDCCH contains uplink timing adjustment information and PUCCH resource indication (PRI), the UE generates HARQ-ACK according to the demodulation result of PDSCH, and sends PUCCH carrying HARQ-ACK according to the uplink timing adjustment information. The UE monitors the second search space again and starts time window T0.

[0331] o If the UE monitors the PDCCH within the time window T0, and the PDCCH triggers the PRACH transmission, the UE transmits the PRACH. The UE monitors the second search space again and starts the time window T0.

[0332] Example 8:

[0333] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the first type RNTI, the second search space configuration information, the PRACH resource, the scheduling information of the second type PDSCH, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0334] -The UE receives the second type PDSCH according to the paging message of the UE.

[0335] -UE generates HARQ-ACK based on the demodulation result of the second type of PDSCH and sends it through PRACH (for example, ACK uses PRACH 1 and NACK uses PRACH 2). UE sends PRACH according to downlink timing. UE monitors the second search space and starts time window T0 and time window T1.

[0336] o If the UE does not detect any PDCCH within time window T1 after sending PRACH, and the maximum number of PRACH transmissions has not been exceeded, the UE sends PRACH again according to the PRACH resources indicated in the paging message applicable to the UE and starts time window T1 again. If the maximum number of PRACH transmissions has been reached, the UE enters the sleep state.

[0337] o If the UE detects PDCCH within time window T1 after sending PRACH, and PDCCH triggers PRACH transmission, the UE can choose to send PRACH according to the resources indicated by this PDCCH. Similarly, the UE determines the corresponding transmission behavior based on time window T1 and the number of PRACH transmissions.

[0338] o If the UE detects PDCCH within time window T1 after sending PRACH, PDCCH schedules PDSCH, and PDCCH contains uplink timing adjustment information and PUCCH resource indication (PRI), the UE generates HARQ-ACK according to the demodulation result of PDSCH, and sends PUCCH carrying HARQ-ACK according to the uplink timing adjustment information. The UE monitors the second search space again and starts time window T0.

[0339] Example 9:

[0340] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the first type RNTI, the second search space configuration information, the PRACH resource, the scheduling information of the second type PDSCH, and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0341] -The UE receives the second type PDSCH according to the paging message of the UE.

[0342] -UE generates HARQ-ACK based on the demodulation result of the second type of PDSCH and sends it through PRACH (for example, ACK uses PRACH sequence 1 and NACK uses PRACH sequence 2). UE sends PRACH according to downlink timing. UE monitors the second search space and starts time window T0 and time window T2.

[0343] o If the UE does not monitor any PDCCH within time window T2 after sending PRACH, the UE falls back to the contention-based random access procedure.

[0344] o If the UE detects PDCCH within time window T2 after sending PRACH, PDCCH triggers PRACH transmission. The UE determines the contention-based or contention-free PRACH transmission process according to the indication of PDCCH.

[0345] oIf the UE detects PDCCH within time window T2 after sending PRACH, PDCCH schedules PDSCH, and PDCCH contains uplink timing adjustment information and PUCCH resource indication (PRI), the UE generates HARQ-ACK according to the demodulation result of PDSCH, and sends PUCCH carrying HARQ-ACK according to the uplink timing adjustment information. The UE monitors the second search space again and starts time window T0. If the UE does not detect any PDCCH within time window T0, the UE enters the sleep state at the end of time window T0, or the UE receives an indication instructing the UE to enter the sleep state within time window T0, the UE enters the sleep state in advance.

[0346] Example 10:

[0347] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the first type RNTI, PRACH resources, scheduling information of the second type PDSCH, and UE behavior (in this example, it is assumed that the UE behavior is downlink transmission in RRC idle / inactive state).

[0348] - The UE receives the second type of PDSCH according to the paging message of the UE. The UE starts the time window T0.

[0349] -The UE attempts to receive PDSCH on every possible second-type PDSCH transmission resource within time window T0. The UE generates HARQ-ACK based on the demodulation result of the second-type PDSCH and sends it through PRACH (for example, ACK uses PRACH sequence 1 and NACK uses PRACH sequence 2). The UE sends PRACH according to the downlink timing.

[0350] oIf the UE does not receive PDSCH for X consecutive times within the time window T0, the UE stops trying to receive PDSCH and enters the sleep state early.

[0351] After the time window T0 ends, the UE enters the sleep state.

[0352] Example 11:

[0353] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the first type RNTI, the second search space configuration information, the PRACH resource, and the downlink data.

[0354] o If the UE demodulates the first type of PDSCH correctly, the UE sends PRACH. The UE monitors the second search space and starts the time window T0.

[0355] o If the UE correctly receives the PDCCH scheduling the paging message but fails to correctly demodulate the first type of PDSCH, the UE monitors the second search space and starts the time window T0.

[0356] o If the UE does not receive the PDCCH scheduling the paging message, the UE enters the sleep state.

[0357] oIf the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or if the UE receives an instruction instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0358] Example 12:

[0359] -The UE receives the PDCCH scheduling the paging message in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the UE behavior indication (in this example, it is assumed that the UE behavior is downlink transmission based on the MO-EDT process in the RRC idle / inactive state).

[0360] -The UE determines a PRACH resource according to the PRACH resource set of MO-EDT and sends the PRACH.

[0361] -UE monitors PDCCH in the second search space, where the second search space is RA-Searchspace, and PDCCH is scrambled by RA-RNTI.

[0362] o If the UE monitors the RA-RNTI scrambled PDCCH (RAR PDCCH) in the second search space, the UE receives the PDSCH (RAR PDSCH).

[0363] oIf the UE demodulates the second type of PDSCH correctly, the UE receives UL grant, uplink timing and other information according to the information corresponding to the UE in the PDSCH.

[0364] -UE sends PUSCH (Msg 3) according to UL grant and uplink timing.

[0365] -UE monitors the second search space again and starts time window T0. If the UE detects that PDCCH schedules PDSCHMsg4, the UE receives PDSCH. The PDSCH contains downlink data. If the UE demodulates the PDSCH correctly and the information in the PDSCH is consistent with the UE, the UE sends an ACK through the PUCCH, or the UE sends an ACK through the PUSCH scheduled by the UL grant in Msg4. Since the UE needs to demodulate PDSCH Msg4 to obtain the UL grant, the time delay from UL grant to PUSCH is greater than the time delay for UL grant scheduling PUSCH in ordinary PDCCH. Similar to Msg3, the time slot where the PUSCH scheduled by PDSCH Msg4 is located is jointly determined based on the time slot offset K0 in the PUSCH time resource allocation table and the additional time slot delay Δ. In some scenarios, the UE needs to generate an application layer ACK based on the received PDSCH Msg4, and the required delay may be greater than the delay of Msg3, so an additional time slot delay Δ different from Msg3 is required. For example, the standard defines a time slot delay Δ for Msg3 and Msg4 respectively.

[0366] Another implementation method is that when PDSCH Msg4 contains downlink data, the UE needs to send ACK or NACK according to the demodulation result of PDSCH. When PDSCH Msg4 does not contain downlink data, the UE only sends ACK when PDSCH is demodulated correctly and the information in PDSCH is consistent with the UE. For example, if the UE knows that PDSCH Msg4 contains downlink data, the UE needs to send ACK or NACK according to the demodulation result of the PDSCH, and the UE sends PUCCH according to the PUCCH resources indicated in the PDCCH that schedules PDSCH Msg4. The ACK and NACK states can be distinguished by different codewords and / or frequency domain and / or time domain resources. If PDSCH Msg4 does not contain downlink data, the UE only sends ACK on PUCCH (PUCCH resources are indicated by the PDCCH that schedules PDSCHMsg4) when PDSCH is demodulated correctly and the information in PDSCH is consistent with the UE, otherwise the UE does not send PUCCH. For another example, if the UE learns that PDSCH Msg4 contains downlink data, the UE sends a PUCCH according to the PUCCH resources indicated in the PDCCH that schedules Msg4, and the PUCCH only carries NACK. The UE sends a PUSCH according to the UL grant in Msg4, and the PUSCH carries ACK. In a specific implementation, if the base station only receives NACK, the base station can schedule the retransmission of Msg4. If the base station receives at least ACK, the base station does not need to schedule the retransmission of Msg4. In this way, the reception performance of Msg4 can be improved.

[0367] Example 13:

[0368] -The UE receives a PDCCH scheduling a paging message in the first search space in the PO, and receives a paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives PRACH configuration information, a first type RNTI, and UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0369] -UE sends PRACH according to the PRACH configuration information.

[0370] -UE monitors PDCCH in the second search space. PDCCH is scrambled by the first type of RNTI, PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources), uplink timing adjustment information. Alternatively, PDCCH is scrambled by the first type of RNTI, PDCCH triggers PRACH transmission. Alternatively, PDCCH is scrambled by the first type of RNTI, schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0371] o If the UE does not receive any downlink response in the second search space at the end of time window T1 after sending the PRACH, the UE attempts to send the PRACH again according to the PRACH configuration information.

[0372] o If the UE detects in the second search space that the PDCCH scrambled by the first type of RNTI schedules the second type of PDSCH, the UE receives the second type of PDSCH.

[0373] The UE generates HARQ-ACK based on the demodulation result of the second type of PDSCH. It determines a PUCCH resource based on the PRI of the PDCCH and the PUCCH resource set indicated by the system information and sends the HARQ-ACK. The UE determines the uplink timing of sending the PUCCH based on the uplink timing adjustment information in the PDCCH. The UE monitors the second search space again and starts the time window T0.

[0374] o If the UE monitors the PDCCH scrambled by the first type of RNTI in the second search space and triggers PRACH transmission, the UE sends PRACH, monitors the second search space again, and starts the time window T0.

[0375] o If the UE detects that the PDCCH schedules PUSCH or PDSCH in the second search space, the UE sends PUSCH or receives PDSCH and sends HARQ-ACK, and monitors the second search space again, and starts the time window T0.

[0376] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0377] Example 14:

[0378] -The UE receives the PDCCH scheduling the paging message in the first search space in the PO, and receives the paging message PDSCH according to the PDCCH. In the paging message applicable to the UE, the UE receives the PRACH configuration information and the UE behavior (in this example, it is assumed that the UE behavior is MT-EDT downlink transmission in RRC idle / inactive state).

[0379] -UE sends PRACH according to the PRACH configuration information.

[0380] -UE monitors PDCCH in the second search space. PDCCH is scrambled by RA-RNTI, and PDCCH contains second-type PDSCH scheduling information. Alternatively, PDCCH is scrambled by first-type RNTI, and schedules PUSCH or PDSCH, or behavior indication (whether to enter sleep state).

[0381] o If the UE does not correctly receive the PDCCH or the second type of PDSCH scrambled with the RA-RNTI corresponding to itself at the end of the time window T1, the UE sends the PRACH again according to the PRACH configuration information.

[0382] o If the UE detects in the second search space that the RA-RNTI-scrambled PDCCH schedules the second type of PDSCH, and the second type of PDSCH contains the RAR corresponding to the UE, the TC-RNTI in the RAR is used as the first type of RNTI. And the third type of PDSCH (carrying downlink data) is received according to the DL grant in the RAR.

[0383] The UE sends the HARQ-ACK information of the third type of PDSCH on the PUSCH or PUCCH according to the uplink timing according to the HARQ-ACK resource indication information in the second type of PDSCH (for example, the UL grant of the PUSCH for carrying HARQ-ACK, or the resource configuration information of the PUCCH for carrying HARQ-ACK) and the uplink timing. The UE monitors the second search space again and starts the time window T0.

[0384] o If the UE detects that the PDCCH scrambled by the first type of RNTI schedules PUSCH or PDSCH in the second search space, the UE sends PUSCH or receives PDSCH and sends HARQ-ACK, and monitors the second search space again, and starts time window T0.

[0385] o If the UE monitors the PDCCH scrambled by the first type of RNTI in the second search space and triggers PRACH transmission, the UE sends PRACH, monitors the second search space again, and starts the time window T0.

[0386] o If the UE does not monitor any PDCCH within the time window T0, the UE enters the sleep state at the end of the time window T0, or the UE receives an indication instructing the UE to enter the sleep state within the time window T0, the UE enters the sleep state in advance.

[0387] Figure 2 A flow chart of a downlink transmission method performed by a user equipment UE according to another exemplary embodiment of the present disclosure is shown.

[0388] Reference Figure 2In step S201, a predefined PDCCH and / or a wake-up signal is received in a third search space.

[0389] In an exemplary embodiment of the present disclosure, the third search space may be used to support the reception of a control channel for downlink transmission by a UE in an RRC idle / deactivated state. The third search space may be used to monitor a PDCCH that schedules a second type of PDSCH.

[0390] In an exemplary embodiment of the present disclosure, the parameters of the third search space are optionally configured, and if the parameters of the specific search space are not configured, the search space of the predefined purpose is used as the specific search space. Here, the third search space is determined according to user equipment specific RRC signaling, or the third search space is determined according to cell system information, or the third search space is determined according to user equipment specific parameters and common search space parameters.

[0391] Here, the configuration information of the third search space may include at least one of the following information: time resource information (e.g., period, offset, time length, symbols occupied within a time unit, etc.), frequency domain resource information (e.g., occupied PRB), space resource information (e.g., QCL / TCI information, precoding granularity, etc.), CCE-REG-mapping information, PDCCH DMRS information, aggregation level information of the search space, monitoring candidate number information, DCI format information. The parameters of the third search space can be optionally configured. If the base station does not configure the third search space, the UE uses the search space of the predefined purpose for the third search space. For example, the search space of the predefined purpose is a search space for monitoring paging control information (the first search space in Embodiment 1), or a search space (searchspaceSIB1) for receiving SIB1 system information, or a search space (RA-searchspace) for receiving random access, or a search space 0 (SearchSpace zero). If the base station does not configure the control resource set (CORESET) corresponding to the search space D, the UE uses the CORESET of the predefined purpose for the CORESET corresponding to the search space D. For example, the CORESET of predefined purpose is a Type 2-PDCCH CSS for paging, or a CORESET of Type-0 PDCCH CSS. The third search space can be configured through UE-specific RRC signaling. In addition, the third search space can be configured through cell system information broadcast. In addition, the third search space can be determined according to UE-specific parameters and common search space parameters.

[0392] To save power, the base station can configure WUS for the UE. The UE attempts to receive WUS starting from the third search space or X time slots / sub-time slots / symbols / absolute time before the start of the third search space. If WUS is not received, the UE does not need to monitor PDCCH and enters sleep state. If the UE receives WUS, the UE performs PDCCH monitoring.

[0393] In an exemplary embodiment of the present disclosure, the third search space can also be used to support the reception of control channels for downlink transmission when the UE is in an RRC connected state. For example, when the UE is in an RRC connected state, the base station has small downlink data transmission, but the UE is out of step in the uplink, the base station can send PDCCH in the third search space to trigger the UE to send PRACH, establish uplink synchronization, and send data in the subsequent downlink PDSCH. Here, the third search space can be a UE-specific search space. According to the specific implementation, the base station can overlap all or part of the resource configuration of the third search space with the search space used to monitor paging control information. In this case, in the overlapping search space, the UE needs to detect both the P-RNTI-scrambled PDCCH, that is, the paging PDCCH, and the first type of RNTI-scrambled PDCCH, that is, the PDCCH used for downlink transmission when the UE is in the RRC idle / deactivated state.

[0394] In an exemplary embodiment of the present disclosure, the UE may receive the PDCCH according to the first type of RNTI, for example, the first type of RNTI is used for CRC scrambling of the PDCCH. The UE may determine the starting point of the UE-specific search space according to the first type of RNTI. The UE receives the PDSCH according to the first type of RNTI. The UE determines the DMRS sequence according to the first type of RNTI. The UE may scramble the PUSCH or PUCCH according to the first type of RNTI. The UE determines the DMRS sequence according to the first type of RNTI. The base station may configure the first type of RNTI. For the specific configuration method, refer to the description in Example 1. For example, the first type of RNTI value is determined by UE-specific RRC signaling configuration or by cell system information broadcast configuration.

[0395] In an exemplary embodiment of the present disclosure, for example, when the UE is in an RRC connected state, the UE may receive the PDCCH according to the C-RNTI.

[0396] In an exemplary embodiment of the present disclosure, the PDCCH may include scheduling information for scheduling the PDSCH. In an exemplary embodiment of the present disclosure, the PDCCH may include indication information of the UE behavior. For example, the PDCCH triggers the UE to perform a random access process (contention-based or contention-free), or the PDCCH instructs the UE to perform PDSCH reception, or the PDCCH indicates the uplink channel type for the UE to feedback HARQ-ACK. For example, the PDCCH indicates that the uplink channel type for feedback HARQ-ACK is PRACH or PUCCH, and / or the PDCCH indicates that PRACH or PUCCH is sent according to downlink timing or uplink timing. Specifically, different indication contents are distinguished by a separate bit field in the DCI of the PDCCH, or different indication contents are distinguished by specific bit values / value combinations in the DCI of the PDCCH, or different indication contents are distinguished by scrambling the PDCCH CRC by different RNTIs, or different DCI formats are used to distinguish different indication contents. When the base station is not sure whether the UE still maintains valid uplink timing, the base station can first trigger the UE to send PRACH through PDCCH to obtain uplink synchronization, and then send PDCCH to schedule PDSCH to carry data after obtaining uplink synchronization. The base station indicates the uplink timing information in PDCCH or PDSCH, so that the UE can perform uplink transmission according to the uplink timing information in subsequent uplink transmissions. Alternatively, when the base station is not sure whether the UE still maintains valid uplink timing, the base station can instruct the UE to carry HARQ-ACK through PRACH, thereby avoiding interference between uplink signals caused by inaccurate uplink timing. In addition, after the UE sends PRACH, the UE still receives PDCCH in search space D, or receives PDCCH in another search space, for example, receives PDCCH in RA-searchspace.

[0397] In an exemplary embodiment of the present disclosure, the UE may not detect the PDCCH in the third search space, and the UE enters a sleep state. For example, the base station configures the third search space with a period of 40 time slots, a time slot offset of 0, a time length of 5 time slots, and the 1st to 3rd symbols in each time slot are the search space. Then, the UE monitors the PDCCH on the 1st to 3rd symbols of each time slot in time slots 0 to 4, time slots 40 to 44, and time slots 80 to 84. For example, if the UE does not detect the PDCCH on the corresponding resources in time slots 40 to 44, it enters a sleep state and tries to receive the PDCCH again in time slots 80 to 84. The UE can periodically receive the PDCCH at the starting point of the third search space within a predefined time window.

[0398] In step S202, a second type PDSCH is received according to the received PDCCH.

[0399] If the UE receives a PDCCH triggering PRACH transmission in the third search space, the UE transmits the PRACH according to the information indicated by the PDCCH. Subsequently, the UE monitors the PDCCH in the third search space and receives the second type of PDSCH according to the received PDCCH. The UE may receive the PDCCH according to the first type of RNTI or C-RNTI.

[0400] The UE may first determine the resources of the second type of PDSCH according to the PDCCH. Here, the UE may determine one or more second type of PDSCH resources according to the PDCCH, and / or the configuration of the RRC connection state, and / or the system information.

[0401] If the PDCCH indicates the spatial characteristics of the second type of PDSCH, the second type of PDSCH may be received according to the indicated spatial characteristics. If there is no indication, the second type of PDSCH may be received according to the spatial characteristics of the received PDCCH. Alternatively, the second type of PDSCH may be received according to the spatial characteristics of the last downlink reception in the connected state.

[0402] In an exemplary embodiment of the present disclosure, the second type PDSCH includes downlink data.

[0403] In an exemplary embodiment of the present disclosure, the second-type PDSCH may include uplink channel information for carrying HARQ-ACK.

[0404] In an exemplary embodiment of the present disclosure, the second type PDSCH may include uplink timing adjustment information (Timing advance).

[0405] In an exemplary embodiment of the present disclosure, the second type PDSCH may include uplink scheduling information (UL grant).

[0406] In an exemplary embodiment of the present disclosure, the second type of PDSCH may include downlink control information. The downlink control information schedules a third type of PDSCH. The third type of PDSCH includes downlink data.

[0407] In an exemplary embodiment of the present disclosure, the second type of PDSCH may indicate the first type of RNTI for the next downlink transmission in RRC idle / inactive state. It may be indicated explicitly by a bit in the PDSCH, or determined implicitly according to the resource pattern of the PDSCH, or indicated explicitly and implicitly in combination.

[0408] In an exemplary embodiment of the present disclosure, the second-class PDSCH indicates a TC-RNTI, and the UE uses the TC-RNTI as the first-class RNTI for the next downlink transmission in the RRC idle / inactive state, for example, for PDCCH scrambling for scheduling downlink data retransmission, and for scrambling of the PDSCH carrying downlink data.

[0409] In an exemplary embodiment of the present disclosure, the second-type PDSCH may be scrambled according to the first-type RNTI and / or the cell ID.

[0410] In an exemplary embodiment of the present disclosure, the second-type PDSCH may be scrambled according to the C-RNTI and / or the cell ID.

[0411] In an exemplary embodiment of the present disclosure, the second type of PDSCH may be Msg 2 or Msg B in a random access procedure. Msg 2 or Msg B may include at least one of the various information and data described above.

[0412] In step S203, the second type PDSCH is demodulated, and ACK feedback is performed according to the demodulation result.

[0413] If the UE demodulates the PDSCH correctly, the UE feeds back an ACK, and if the UE does not demodulate the PDSCH correctly, the UE does not feed back any feedback. Alternatively, the UE feeds back an ACK or a NACK according to the demodulation result of the PDSCH.

[0414] In an exemplary embodiment of the present disclosure, HARQ-ACK can be carried by PRACH. The base station configures a dedicated PRACH resource for the UE, and the PRACH resource does not belong to the cell common PRACH resource set indicated in the system information (e.g., SIB1), or belongs to the cell common PRACH resource. Alternatively, the base station configures a PRACH resource set dedicated to the UE in the downlink transmission process when the UE is in the RRC idle / deactivated state in the system information, and the UE selects a PRACH resource from the set according to predefined rules. For example, the PRACH resource is determined based on the received PDCCH resource and / or PDSCH resource. PRACH resources include time-frequency domain and codeword resources.

[0415] In addition, HARQ-ACK can be carried by PUCCH. PUCCH resources can be optionally configured. The base station can configure dedicated PUCCH resources for the UE, which are dedicated to the UE during downlink transmission when it is in the RRC idle / deactivated state. For example, the base station configures PUCCH resources for the UE in the RRC idle / deactivated state and the PUCCH resources for the UE in the RRC connected state respectively. Alternatively, the base station configures a set of PUCCH resources for both the RRC idle / deactivated state and the RRC connected state. If the base station does not configure UE-specific PUCCH resources, the standard predefined PUCCH resource set and the PUCCH resources determined by the indication in the system information can be used for the UE in the downlink transmission process when the RRC idle / deactivated state. For example, when the UE is in the RRC connected state, the base station configures one or more PUCCH resources for the UE, which are dedicated to the UE during downlink transmission when the UE is in the RRC idle / deactivated state. The base station determines one PUCCH resource among the configured one or more PUCCH resources through PDCCH. For another example, the standard predefines one or more groups of PUCCH resources, the base station indicates one group of the one or more groups of PUCCH resources in the system information (eg, pucch-ResourceCommon), and the base station determines one PUCCH resource in the group of PUCCH resources through PDCCH.

[0416] PUCCH resources may include one or more of the following: PUCCH format, frequency domain resources of PUCCH, time domain resources of PUCCH, codeword resources of PUCCH, spatial characteristics of PUCCH (for example, which reference signal QCL of which cell), set of HARQ-ACK feedback delay K1, PUCCH power control information, PUCCH maximum code rate, cyclic prefix of PUCCH, etc. In PUCCH power control, the closed-loop power control parameters are not accumulated with the closed-loop power control parameters in the RRC connected state, that is, the closed-loop power control parameters of the first PUCCH transmission when the UE is in the RRC idle / deactivated state are reset to 0, and accumulated according to the closed-loop power control parameters of the PDCCH when the UE is in the RRC idle / deactivated state.

[0417] In an exemplary embodiment of the present disclosure, it can be determined whether to use PUCCH or PRACH to send HARQ-ACK according to the indication of PDCCH or PDSCH. Specifically, the base station can configure the UE to use PUCCH or PRACH to send HARQ-ACK. For example, when the UE is in an RRC connected state, the base station indicates through high-layer signaling that the UE sends the uplink channel of HARQ-ACK when it is in an RRC idle / deactivated state. The UE can determine whether to use PUCCH or PRACH to send HARQ-ACK based on whether the uplink timing is valid. When the uplink timing maintained by the UE fails, the UE can only send PRACH. Here, the time resource of the PRACH resource may not be earlier than the PDSCH time resource. Optionally, the time difference between the time resource of the PRACH resource and the PDSCH time resource is not less than a predefined delay. For example, after the UE receives the PDCCH in step 1, it receives the PDSCH and sends the PRACH on the first available PRACH resource after the PDSCH. Depending on the decoding result of the PDSCH, the time and / or frequency domain and / or codeword resources of the PRACH may be different. Optionally, the time resource of the PRACH resource is not earlier than the time resource of the uplink channel for sending HARQ-ACK indicated by the PDCCH. Optionally, the time resource of the PRACH resource is not earlier than the time resource of the PUCCH for sending HARQ-ACK indicated by the PDCCH. Optionally, the time resource of the PRACH resource is not earlier than the time resource of the PDCCH in step 1. For example, after receiving the PDCCH, the UE immediately attempts to send PRACH on the available PRACH resources without attempting to receive the PDSCH scheduled by the PDCCH.

[0418] If the base station does not support the UE's spontaneous transmission of PRACH during downlink transmission when the RRC is idle / deactivated, the UE sends PUCCH to carry HARQ-ACK when the UE's uplink timing is valid, and does not send PUCCH when the UE's uplink timing is invalid, that is, DTX. One implementation method is that when the base station does not detect the PUCCH from the UE, the base station can send PDCCH to trigger the UE to send PRACH. When the UE receives a PDCCH triggering PRACH transmission, if the PDCCH indicates a contention-free PRACH transmission, for example, the ra-PreambleIndex indicated in the PDCCH is a non-zero value, the UE can perform contention-based PRACH transmission. For a detailed description, see Figure 1 If the PDCCH indicates contention-based PRACH transmission, for example, the ra-PreambleIndex indicated in the PDCCH is all zero, the UE may fall back to the contention-based random access procedure.

[0419] When the UE's uplink timing is invalid, the UE does not send PUCCH. The UE starts time window T3. If the UE does not receive any instruction from the base station within time window T3, the UE falls back to the contention-based random access process. The length of time window T3 is ≥ 0.

[0420] The base station may configure the BWP for sending the PRACH or PUCCH, or the BWP for sending the PRACH or PUCCH may be an initial BWP, that is, a UL BWP for initial random access in the cell where the UE is located.

[0421] After step S203, the UE may continue to monitor the PDCCH. Further, the UE monitors the PDCCH within a predetermined time window. Among them, the predefined time window is the time window of the third search space, which is determined by the time starting point of the third search space and the time length duration. For example, the base station configures the third search space with a period of 40 time slots, a time slot offset of 0, a time length of 5 time slots, and the 1st to 3rd symbols in each time slot are the search space. In this example, the starting point of the time window is the 1st symbol in time slots 0, 40, 80..., and the end position of the time window is the 3rd symbol in time slots 4, 44, 84..., respectively. The UE monitors the PDCCH on the 1st to 3rd symbols of each time slot in each time window. When the time window ends, the UE enters a sleep state. Alternatively, the predefined time window is determined according to the time window of the third search space and the predefined second time length. The configuration of the third search space is as above, and the predefined second time length is 2 time slots. Then, the starting point of the predetermined time window is the first symbol in time slots 0, 40, 80..., and the ending position of the time window is the last symbol in time slots 6, 46, 86..., respectively. Among them, the UE only monitors PDCCH in the third search space, but can receive PDSCH or send PUSCH / PUCCH within the predefined time window. Alternatively, the predefined time window is determined according to the time window of the third search space, the predefined second time length, and the end position of PDSCH or PUCCH or PUSCH. For example, when the UE receives PDCCH scheduling PDSCH or PUSCH transmission within the time window of the third search space, after the UE sends HARQ-ACK of PDSCH or sends PUSCH, the predefined time window is determined based on the predefined second time length with the end position of PUCCH or PUSCH as the starting point. In one way, the UE receives PDCCH on the third search space resources within the predefined time window, and in another way, the third search space is extended to other time slots within the predefined time window, and the UE can receive PDCCH in these resources. For example, the third search space configured by the base station is the 1st to 3rd symbols of each time slot in time slots 0 to 4, time slots 40 to 44, and time slots 80 to 84. Assume that the predefined second time length is 2 time slots. The UE detects the PDCCH on the 1st to 3rd symbols of time slot 42, schedules the PDSCH to be sent in time slot 43, and sends the PUCCH carrying HARQ-ACK in time slot 44. Then, starting from the starting point of time slot 45, a time window with a length of 2 time slots is started. The UE still needs to detect PDCCH on the 1st to 3rd symbols in time slots 45 and 46. If the UE does not monitor any PDCCH, the UE can enter the sleep state at the end of the 3rd symbol of time slot 46.

[0422] To prevent the UE from changing its serving cell and causing the signal sent by the base station on the original serving cell to be unable to be received by the UE, the base station can configure the UE to report this change to the base station when the UE changes its serving cell. For another example, when the base station configures the UE with a transmission mode for receiving a predefined PDCCH and / or wake-up signal in the third search space, if the UE changes its serving cell, the UE needs to report this change to the base station.

[0423] In an exemplary embodiment of the present disclosure, Figure 1 The description of time windows in also applies here.

[0424] In step S204, when the predefined sleeping condition is met, the sleeping state is entered.

[0425] In order to better understand the various solutions of this embodiment, several examples are given below, but the solutions of this embodiment are not limited to these examples. In each step, the specific implementation method will not be repeated, and reference is made to the foregoing description.

[0426] Example 1:

[0427] -The base station configures the UE to monitor the PDCCH in the third search space when the UE is in the RRC idle / inactive state. The base station configures the third search space information, the first type of RNTI, and the PUCCH resource set.

[0428] -UE monitors PDCCH in the third search space. PDCCH is scrambled by the first type of RNTI. PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources), uplink timing adjustment information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state), or PDCCH triggers PRACH transmission.

[0429] o If the UE detects that the PDCCH schedules the second type of PDSCH in the third search space:

[0430] If the uplink timing of the UE is valid, the UE generates HARQ-ACK according to the PDSCH demodulation result, and sends PUCCH according to the uplink timing. The UE continues to monitor the third search space.

[0431] If the UE's uplink timing is invalid, the UE does not send the PUCCH. The UE continues to monitor the third search space.

[0432] o If the UE detects that PDCCH triggers PRACH transmission in the third search space, the UE transmits PRACH according to the PRACH resources indicated in the PDCCH. The UE continues to monitor the third search space.

[0433] o If the UE detects that the PDCCH schedules the PUSCH in the third search space, the UE sends the PUSCH according to the PUSCH resources indicated in the PDCCH. The UE continues to monitor the third search space.

[0434] o If the UE does not monitor the PDCCH at the end of the third search space time length (duration), or monitors an indication of entering the sleep state, the UE enters the sleep state.

[0435] Example 2:

[0436] -The base station configures the UE to monitor the PDCCH in the third search space when the UE is in the RRC idle / inactive state. The base station configures the third search space information, the first type of RNTI, and the PUCCH resource set.

[0437] -UE monitors PDCCH in the third search space. PDCCH is scrambled by the first type of RNTI. PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources), uplink timing adjustment information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state), or PDCCH triggers PRACH transmission.

[0438] o If the UE detects that the PDCCH schedules the second type of PDSCH in the third search space:

[0439] If the UE's uplink timing is valid, the UE generates HARQ-ACK according to the PDSCH demodulation result, and sends PUCCH according to the uplink timing. The UE continues to monitor the third search space and starts the time window.

[0440] If the uplink timing of the UE is invalid, the UE does not send the PUCCH. The UE continues to monitor the third search space and starts the time window.

[0441] o If the UE detects that PDCCH triggers PRACH transmission in the third search space, the UE transmits PRACH according to the PRACH resources indicated in the PDCCH. The UE continues to monitor the third search space and starts the time window.

[0442] o If the UE detects that PDCCH schedules PUSCH in the third search space, the UE sends PUSCH according to the PUSCH resources indicated in the PDCCH. The UE continues to monitor the third search space and starts the time window.

[0443] o If the UE does not detect a new PDCCH at the end of the time window, or detects an indication to enter the sleep state, the UE enters the sleep state.

[0444] o If the UE does not monitor any PDCCH from the start point of the third search space to the end point of the third search space determined according to the search space duration, or monitors an indication of entering the sleep state, the UE enters the sleep state.

[0445] Example 3:

[0446] -The base station configures the UE to monitor the PDCCH in the third search space when the UE is in the RRC idle / inactive state. The base station configures the third search space information, the first type of RNTI, and the PUCCH resource set.

[0447] -UE monitors PDCCH in the third search space. PDCCH is scrambled by the first type RNTI. PDCCH contains PDSCH scheduling information, PUCCH resource information (PRI indicates which set of PUCCH resources), uplink timing adjustment information, or schedules PUSCH, or PDCCH contains behavior indication (whether to enter sleep state).

[0448] o If the UE detects that the PDCCH schedules the second type of PDSCH in the third search space,

[0449] If the uplink timing of the UE is valid, the UE generates HARQ-ACK according to the PDSCH demodulation result, and sends PUCCH according to the uplink timing. The UE continues to monitor the third search space.

[0450] If the UE's uplink timing is invalid and the base station supports MO-EDT-based transmission, the UE switches to the MO-EDT transmission mode.

[0451] o If the UE detects that the PDCCH schedules the PUSCH in the third search space, the UE sends the PUSCH according to the PUSCH resources indicated in the PDCCH. The UE continues to monitor the third search space.

[0452] o If the UE does not monitor the PDCCH before the end position of the third search space, or monitors an indication of entering the sleep state, the UE enters the sleep state.

[0453] Figure 3 A flow chart of a downlink transmission method performed by a user equipment UE according to another exemplary embodiment of the present disclosure is shown.

[0454] Reference Figure 3 In step S301, a predefined downlink signal is received in a predefined downlink resource.

[0455] In an exemplary embodiment of the present disclosure, the predefined downlink resource is a predefined second-category PDSCH resource, which is configured by the base station when the user equipment is in an RRC connected state and is used for downlink transmission in an RRC idle / inactive state. Alternatively, the predefined downlink resource is a resource of a RAR PDSCH indicated by a RAR PDCCH.

[0456] In an exemplary embodiment of the present disclosure, the base station may configure a predefined PDSCH resource for downlink transmission in the RRC idle / inactive state when the UE is in the RRC connected state. Similar to the DL SPS in the RRC connected state, the predefined PDSCH resource for downlink transmission in the RRC idle / inactive state includes one or more of the following parameters: PDSCH period, time offset, number of repetitions, symbol start / length / end symbol, frequency domain resources, spatial characteristics, etc.

[0457] Here, for example, the signaling for configuring the PDSCH resources in the RRC idle / inactive state and the RRC signaling for configuring the DL SPS parameters in the RRC connected state can be the same signaling, and the base station can also use a dedicated signaling to indicate whether the DL SPS parameters are only used for the RRC idle / inactive state, only used for the RRC connected state, or used for both the RRC idle / inactive state and the RRC connected state during configuration. When the DL SPS can be used for the RRC idle / inactive state, additional DL SPS resources need to be configured. For example, the signaling for configuring the PDSCH parameters in the RRC idle / inactive state and the RRC signaling for configuring the DL SPS parameters in the RRC connected state can be two different RRC signalings, that is, the parameters are configured separately, for example, the corresponding C-RNTI value (SPS-RNTI) and the transmission time interval and other parameters may have different configured values.

[0458] To save power, the base station can configure WUS for the UE. The UE starts to try to receive WUS from X time slots / sub-time slots / symbols / absolute time before the start of the predefined PDSCH time resource. If WUS is not received, the UE does not need to receive PDSCH and enters the sleep state. If the UE receives WUS, the UE receives PDSCH.

[0459] In an exemplary embodiment of the present disclosure, during a random access process, the base station may indicate the resources of the RARPDSCH through the RAR PDCCH, and the UE receives the second type of PDSCH, ie, the RAR PDSCH, on the corresponding resources according to the indication of the RAR PDCCH.

[0460] In step S302, an ACK feedback is performed according to the received downlink signal.

[0461] In an exemplary embodiment of the present disclosure, if the UE demodulates the PDSCH correctly, the UE feeds back ACK, and if the UE does not demodulate the PDSCH correctly, the UE does not feed back. Alternatively, the UE feeds back ACK or NACK according to the demodulation result of the PDSCH.

[0462] In an exemplary embodiment of the present disclosure, when the second type PDSCH is Msg B RAR PDSCH, if the UE demodulates a successfully matched Msg B RAR sPDU in the MsgB RAR PDSCH, the UE feeds back ACK.

[0463] In an exemplary embodiment of the present disclosure, ACK and NACK may be carried by PRACH or PUCCH, or ACK may be carried by PUSCH.

[0464] In order to send ACK or NACK, the UE needs to determine the uplink time slot for sending HARQ-ACK. According to one implementation, the HARQ-ACK timing information (PDSCH-to-HARQ-timing-indicator) is indicated in the PDCCH that schedules the PDSCH, and the UE determines the uplink time unit for sending HARQ-ACK based on the timing information and the end position of the PDSCH. For example, the end position of the PDSCH corresponds to the uplink time slot n, and the HARQ-ACK timing information indicates k uplink time slots, then the uplink time unit for sending HARQ-ACK is the uplink time slot n+k. The base station can configure a set of HARQ-ACK timing information and indicate one of them through the DCI, or the standard predefines a set of HARQ-ACK timing information and indicates one of them through the DCI. Or the base station can configure or predefine a HARQ-ACK timing information k. Usually, the setting of k needs to take into account the minimum delay for the UE to process the PDSCH, that is, the shortest processing time between the UE receiving the PDSCH and generating the PUCCH carrying the HARQ-ACK. The k indicated by the base station cannot be less than this minimum processing time. In Release-15, the standard predefined HARQ-ACK timing set is {1,2,3..8} uplink time slots. This predefined set is used when the base station does not configure a dedicated HARQ-ACK timing set for the UE. For example, the HARQ-ACK feedback of Msg4 during random access, or the HARQ-ACK feedback of PDSCH scheduled by DCI in fallback mode.

[0465] In some scenarios, the UE receives PDSCH. If the CRC check of the PDSCH succeeds, the UE generates an ACK. If the CRC check fails, the UE generates a NACK and sends an ACK / NACK through the PUCCH. However, in other scenarios, after completing the CRC check, the UE needs to further process the MAC PDU carried by the PDSCH and determine whether to generate an ACK based on the MAC PDU. For example, during the random access process, the UE receives a RAR PDSCH. After the CRC check succeeds, the UE needs to further process the MAC PDU carried by this PDSCH and successfully obtain the successfully matched MAC sPDU RAR before generating an ACK and preparing to send this ACK information on the PUCCH resource. The UE determines k1 based on the HARQ-ACK timing information indicated in the Msg B RAR PDSCH or RAR PDCCH, and the time slot n where the end position of the received RAR PDSCH is located, and determines the uplink time slot n+k1 for sending the PUCCH. In addition, the UE needs to obtain the uplink timing advanced commond from the successful MAC sPDU RAR to determine the PUCCH transmission timing. Considering the additional time required to process the MAC PDU, the value of the HARQ-ACK timing k1 in this case is often larger than the value of the HARQ-ACK timing k in normal cases. The current n+k mechanism may not be able to meet the UE's processing time. In order to solve this problem, the present invention proposes the following solutions.

[0466] Solution 1:

[0467] The uplink time slot of the PUCCH used to determine the ACK feedback of MsgB RAR PDSCH is n+k+j+Δ, that is, k1=k+j+Δ. Among them, k is the HARQ-ACK timing set predefined by the standard. 0 The bit indicates one of the values, such as X 0 = 3 bits indicating a value in {1,2,..8}, or X 0 =2. The values ​​of j and Δ can be determined according to the subcarrier spacing parameter μ carrying the PUCCH. PUCCH Table 4 is an illustration of the value of j, and Table 5 is an illustration of the value of Δ. PUCCH =0,1,2,3 respectively indicate that the subcarrier spacing SCS is 15,30,60,120KHz.

[0468] Preferably, the value range of j can reuse the PUSCH timing j predefined in the standard, that is, the time slot offset K2 from PDCCH to PUSCH. Preferably, the value range of j can additionally define a set of values.

[0469] Preferably, the value range of Δ can reuse the additional time slot offset Δ of the first PUSCH scheduled by RAR predefined in the standard, where the time slot offset from the UL grant in RAR to the first PUSCH scheduled by RAR is K2+Δ. Preferably, the value range of Δ can additionally define a set of values.

[0470] <![CDATA[μ PUCCH ]]> j 0 1 1 1 2 2 3 3

[0471] Table 4

[0472] <![CDATA[μ PUCCH ]]> Δ 0 2 1 3 2 4 3 6

[0473] Table 5

[0474] Preferably, j+Δ is greater than or equal to the UE processing delay from when the UE decodes the Msg.B RAR PDSCH and obtains the uplink timing command (TAC, Timing advance command) in its RAR MAC sPDU to when it sends the PUCCH.

[0475] Preferably, j is greater than or equal to the minimum delay for preparing PUCCH, and Δ is greater than or equal to the minimum delay for parsing MAC sPDU described above.

[0476] Option 2:

[0477] The uplink time slot of the PUCCH used to determine the ACK feedback of MsgB RAR PDSCH is n+k+Δ, that is, k1=k+Δ. Among them, k is the HARQ-ACK timing set predefined by the standard. 0 The bit indicates one of the values, such as X 0 = 3 bits indicating a value in {1,2,..8}, or X 0 =2. Similarly, the value of Δ can be determined based on the subcarrier spacing parameter μ carrying the PUCCH. PUCCH Determine, as shown in Table 5.

[0478] Preferably, Δ is greater than or equal to the UE processing delay from when the UE decodes the Msg.B RAR PDSCH and obtains the uplink timing command TAC in its RAR MAC sPDU to when it sends the PUCCH.

[0479] Preferably, Δ is greater than or equal to the minimum delay for parsing the MAC sPDU described above. It can be considered that the delay for preparing the PUCCH is already considered in k.

[0480] Option 3:

[0481] The uplink time slot of the PUCCH used to determine the ACK feedback of MsgB RAR PDSCH is n+k1, that is, k1=k+j. Among them, k is the HARQ-ACK timing set predefined by the standard. 0 The bit indicates one of the values, such as X 0 = 3 bits indicating a value in {1,2,..8}, or X 0 =2. Similarly, the value of j can be determined based on the subcarrier spacing parameter μ carrying the PUCCH. PUCCH Determine, as shown in Table 4.

[0482] Preferably, j is greater than or equal to the UE processing delay from when the UE decodes the Msg.B RAR PDSCH and obtains the uplink timing command TAC in its RAR MAC sPDU to when it sends the PUCCH.

[0483] Option 4:

[0484] The uplink time slot of the PUCCH used to determine the ACK feedback of MsgB RAR PDSCH is n+k+ Where k is a HARQ-ACK timing set predefined by the standard, for example, a value in {1, 2, .. 8}. 0 The bit indicates one of the values, such as X 0 = 3 bits indicating a value in {1,2,..8}, or X 0 =2. According to T 0 Determine the number of uplink time slots. Preferably, T 0 =0.5. Among them, is the number of time slots in a subframe, T sf The time length of a subframe is 1 millisecond.

[0485] Option 5:

[0486] The uplink time slot of the PUCCH used to determine the ACK feedback of MsgB RAR PDSCH is n+k+ Right now Where k is the HARQ-ACK timing set predefined by the standard. Msg B RAR PDSCH or PDCCH is transmitted through X 0 The bit indicates one of the values, such as X 0 = 3 bits indicating a value in {1,2,..8}, or X 0 =2. Among them, is the number of time slots in a subframe, T sfThe length of a subframe is 1 millisecond, N T,1 It is the PDSCH processing time when the UE processing capability is 1 and the PDSCH has an additional reference signal DMRS, which can be expressed as N1 symbols.

[0487] Option 6:

[0488] The uplink time slot of the PUCCH used to determine the ACK feedback of MsgB RAR PDSCH is n+k1. The standard predefines the set of k1, and this set and the set of k are defined or configured separately. 0 The bit indicates the value of one of the k1s, for example, X 0 =3 or 2.

[0489] The method of determining the HARQ-ACK PUCCH uplink time slot of Msg B RAR PDSCH by adding an additional time offset on the basis of the general k not only ensures sufficient processing delay, but also realizes flexible allocation of resources of this type of PUCCH and other types of PUCCH (feedback time slot determined according to n+k), thereby improving PUCCH resource efficiency.

[0490] In an exemplary embodiment of the present disclosure, whether to send PUCCH can be determined based on whether the uplink timing is valid. If the uplink timing is valid, the PUCCH carrying ACK or NACK is sent according to the uplink timing, and if the uplink timing fails, the PUCCH is not sent; or, if the uplink timing is valid, the PUCCH carrying ACK or NACK is sent according to the uplink timing, and if the uplink timing fails, the PRACH is sent and the PUCCH is not sent.

[0491] In an exemplary embodiment of the present disclosure, after receiving a downlink signal (second type PDSCH), the PDCCH may be monitored in the third search space within a predetermined time window. Here, the predetermined time window may be based on any of the following as a starting point: the end symbol of the uplink channel for ACK feedback by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the uplink channel for ACK feedback by the user equipment is located, the end symbol of the PDSCH sent by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the PDSCH sent by the user equipment is located, the end symbol of the PUSCH sent by the user equipment, and the end position of the time slot / sub-time slot where the end symbol of the PUSCH sent by the user equipment is located.

[0492] In an exemplary embodiment of the present disclosure, HARQ-ACK may be carried through PRACH, or HARQ-ACK may be carried through PUCCH.

[0493] If the base station configures PRACH / PUCCH resources when the UE is in the RRC connected state, or configures PRACH / PUCCH resources in the second type of PDSCH, or the base station configures a PRACH / PUCCH resource set dedicated to the UE in the downlink transmission process when the UE is in the RRC idle / deactivated state in the system information, the UE can select a PRACH / PUCCH resource from the set according to a predefined rule. For example, the PRACH / PUCCH resource is determined according to the received PDCCH resource and / or PDSCH resource.

[0494] Specifically, the base station can indicate the use of PRACH or PUCCH to send HARQ-ACK through the second type of PDSCH. In addition, the base station can configure the UE to use PUCCH or PRACH to send HARQ-ACK. For example, when the UE is in an RRC connected state, the base station indicates through high-layer signaling that the UE sends the uplink channel of HARQ-ACK when it is in an RRC idle / deactivated state. In addition, the UE determines whether to use PUCCH or PRACH to send HARQ-ACK based on whether the uplink timing is valid. When the uplink timing maintained by the UE fails, the UE can only send PRACH. In addition, the base station indicates the use of uplink timing or downlink timing to send HARQ-ACK through the second type of PDSCH.

[0495] If the base station does not support the UE's spontaneous transmission of PRACH during downlink transmission when the RRC is idle / deactivated, the UE sends PUCCH to carry HARQ-ACK when the UE's uplink timing is valid, and does not send PUCCH when the UE's uplink timing is invalid, that is, DTX. One implementation method is that when the base station does not detect the PUCCH from the UE, the base station can send PDCCH to trigger the UE to send PRACH. When the UE receives a PDCCH triggering PRACH transmission, if the PDCCH indicates a contention-free PRACH transmission, for example, the ra-PreambleIndex indicated in the PDCCH is a non-zero value, the UE performs contention-based PRACH transmission. For a detailed description, see Figure 1 If the PDCCH indicates contention-based PRACH transmission, for example, the ra-PreambleIndex indicated in the PDCCH is all zero, the UE may fall back to the contention-based random access procedure.

[0496] When the UE's uplink timing is invalid, the UE does not send PUCCH. The UE starts time window T3. If the UE does not receive any instruction from the base station within time window T3, the UE falls back to the contention-based random access process. The length of time window T3 is ≥ 0.

[0497] After step S302, the UE may continue to monitor the PDCCH. Further, the UE monitors the PDCCH within a predetermined time window T0. Figure 1 or Figure 2 Description of the search space and time window T0 in .

[0498] In an exemplary embodiment of the present disclosure, when a predefined condition C1 is satisfied, a predefined state X is entered.

[0499] Figure 4 A flow chart of a downlink transmission method performed by a user equipment UE according to another exemplary embodiment of the present disclosure is shown.

[0500] Reference Figure 4 , in step S401, a predefined PDCCH is received in a predefined first search space.

[0501] In step S402, a first-type PDSCH is received according to a PDCCH received in a first search space.

[0502] In step S403, a PRACH is sent according to the first type of PDSCH.

[0503] In step S404, a PDCCH is monitored in a predefined second search space within a predetermined time window.

[0504] In step S405, it is determined whether the PDCCH is monitored within a predetermined time window. If yes, step S406 is executed; otherwise, step S410 is directly executed.

[0505] In step S406, a monitored PDCCH is received in a second search space;

[0506] In step S407, it is determined whether the PDCCH received in the second search space indicates receiving the second type of PDSCH. If yes, step S408 is executed. Otherwise, if the PDCCH received in the second search space indicates entering the sleep state, step S410 is directly executed.

[0507] In step S408, a second type of PDSCH is received according to the PDCCH received in the second search space.

[0508] In step S409, the second type PDSCH is demodulated, HARQ-ACK feedback is performed according to the demodulation result, and the process jumps to step S405.

[0509] In step S410, enter the sleep state.

[0510] In an exemplary embodiment of the present disclosure, in step S406, if the PDCCH received in the second search space includes PUSCH scheduling information, the UE sends the PUSCH according to the scheduling information and returns to step S405.

[0511] In addition to the methods described above, the base station can also trigger the UE to perform contention-based 2-step or 4-step random access through a paging message, and carry downlink data in MsgB or Msg4 to achieve downlink transmission of the UE in the RRC idle / inactive state. Similarly, after receiving MsgB and Msg4 containing downlink data, the UE monitors the PDCCH within a predefined time window and enters the sleep state if the conditions are met.

[0512] According to the various methods described above, the base station or UE can switch between multiple downlink transmission modes. For example, the base station can configure the UE to perform RRC idle state / inactive state transmission according to the transmission mode of embodiment one, two or three when the UE is in the RRC connected state. For another example, the base station can indicate the transmission mode based on MT-EDT or MO-EDT in the RRC idle state / inactive state in the first type PDSCH. According to the various methods described above, the UE can report its own capabilities and which RRC idle state / inactive state downlink transmission methods it can support, for example, it can support the transmission modes of embodiments one and / or two and / or three. The base station configures the RRC idle state / inactive state downlink transmission method for the UE according to the supportable downlink transmission method reported by the UE. In addition, the base station can also configure the RRC idle state / inactive state downlink transmission method for the UE according to the type information of the UE, for example, whether the UE has a static characteristic.

[0513] The step of UE sending PRACH in the above description can be replaced by UE sending Msg A (including PRACH and MsgA PUSCH, Msg A PUSCH carries specific uplink control information), which is the first step of the two-step random access process in the prior art.

[0514] If the UE finds that the uplink synchronization fails before receiving downlink data, the UE performs uplink synchronization. Figure 2 or Figure 3 If the UE finds that the uplink synchronization fails before step S201 or step S301, the UE performs a contention-based random access process, or the UE sends PRACH on the dedicated PRACH resource configured by the base station. This allows the UE to send HARQ-ACK according to the effective uplink timing after receiving the PDSCH.

[0515] In the above Figures 1 to 4In the description, by supporting different downlink transmission modes, it can better adapt to different business characteristics and terminal specifics and improve transmission efficiency.

[0516] In the above Figures 1 to 4 In the description, by instructing the base station to instruct the UE to fall back to the contention-based random access process or to establish an RRC connection, network resources can be allocated more optimally and the reliability of downlink transmission can be ensured.

[0517] In the above Figures 1 to 4 In the description, triggering the UE to fall back to the contention-based random access process or establish an RRC connection through predefined rules can better allocate resources in the network and ensure the reliability of downlink transmission.

[0518] The above has been combined Figures 1 to 4 A downlink transmission method performed by a user equipment according to an exemplary embodiment of the present disclosure is described. Figure 5 and Figure 8 A user equipment and units thereof according to an exemplary embodiment of the present disclosure are described. Figure 5 A block diagram of a user equipment according to an exemplary embodiment of the present disclosure is shown.

[0519] Reference Figure 5 The user equipment includes: a first PDCCH receiving unit 51, a first PDSCH receiving unit 52, a PRACH sending unit 53, a second PDCCH receiving unit 54, a second PDSCH receiving unit 55, a feedback unit 56 and a sleeping unit 57.

[0520] The first PDCCH receiving unit 51 is configured to receive a predefined PDCCH in the first search space when the predefined downlink resource is the first search space.

[0521] The first PDSCH receiving unit 52 is configured to receive a first-type PDSCH according to a PDCCH received in a first search space.

[0522] In an exemplary embodiment of the present disclosure, downlink data may be included in the first type PDSCH.

[0523] In an exemplary embodiment of the present disclosure, the first type PDSCH includes at least one of the following information: resource information of PRACH, resource information of the second type PDSCH, ACK resource information, transmission mode information, first type RNTI, and resource information of the second search space.

[0524] In an exemplary embodiment of the present disclosure, the user equipment also includes a mode determination unit, which is configured to determine at least one of the following transmission modes according to the first type of PDSCH after receiving the first type of PDSCH: performing early data transmission EDT in RRC idle state / inactive state, performing early data transmission MT-EDT based on terminal termination in RRC idle state / inactive state, performing early data transmission MO-EDT based on terminal initiation in RRC idle state / inactive state, establishing a wireless resource control RRC connection, performing contention-based random access, performing contention-free random access, performing a 4-step random access channel or a 2-step random access channel, and falling back to a specific transmission process when predefined conditions are met.

[0525] In an exemplary embodiment of the present disclosure, resource information of the PRACH may be determined according to the first type PDSCH.

[0526] In an exemplary embodiment of the present disclosure, resource information of the second type PDSCH may be determined according to the first type PDSCH.

[0527] In an exemplary embodiment of the present disclosure, resource information of ACK may be determined according to the first type PDSCH.

[0528] In an exemplary embodiment of the present disclosure, the first type RNTI may be determined according to the first type PDSCH.

[0529] In an exemplary embodiment of the present disclosure, the second search space may be determined according to the first type PDSCH.

[0530] In an exemplary embodiment of the present disclosure, the resource information of PRACH contained in the first type of PDSCH includes at least one of the following information: a preamble sequence index, a preamble sequence repetition number, a PRACH format, a PRACH time-frequency resource, a synchronization signal for determining the RACH timing, and broadcast channel SS / PBCH information.

[0531] The PRACH transmitting unit 53 is configured to transmit the PRACH according to the first type PDSCH.

[0532] The second PDCCH receiving unit 54 is configured to receive a PDCCH in the second search space.

[0533] In an exemplary embodiment of the present disclosure, the user equipment may also include: a space determination unit, configured to determine the second search space according to at least one of the following methods when the predefined downlink resource is the first search space: determining the second search space according to configuration information of the cell system information, determining the second search space according to configuration information of the user equipment dedicated RRC signaling, determining the second search space according to the first type of PDSCH, determining the second search space in combination with the multiple signalings, and determining the second search space according to the predefined search space.

[0534] In an exemplary embodiment of the present disclosure, the first PDCCH receiving unit 52 and the second PDCCH receiving unit 54 may be configured to receive the PDCCH according to the first type RNTI or the RA-RNTI. Here, the first type RNTI may be determined by at least one of the following: the first type RNTI allocated when the user equipment is in the RRC connected state, the RNTI included in the first type PDSCH, the C-RNTI allocated when the user equipment was in the RRC connected state last time, the paging user equipment identity PagingUE-Identity and the random access RNTI RA-RNTI.

[0535] In an exemplary embodiment of the present disclosure, the PDCCH received in the second search space may include at least one of the following: scheduling information of PDSCH, uplink timing adjustment information, uplink channel information of feedback HARQ-ACK, first type RNTI information, and an indication of the user equipment transmission mode.

[0536] In an exemplary embodiment of the present disclosure, the indication of the transmission mode of the user equipment may include: an indication of sending a PRACH, an indication of receiving a PDSCH, and an indication of feeding back a HARQ-ACK via a PRACH or a PUCCH.

[0537] In an exemplary embodiment of the present disclosure, different indication contents may be distinguished by a separate bit field in the DCI of the PDCCH in the second search space, or, different indication contents may be distinguished by a specific bit value / value combination in the DCI of the PDCCH in the second search space, or, different indication contents may be distinguished by performing CRC scrambling on the PDCCH in the second search space through different RNTIs, or, different indication contents may be distinguished by different DCI formats.

[0538] In an exemplary embodiment of the present disclosure, the user equipment may further include: a fallback unit configured to fall back to a contention-based random access process when no corresponding downlink response is received in the second search space within the time window. Alternatively, the user equipment may further include: a retransmission unit configured to retransmit a dedicated PRACH when no corresponding downlink response is received in the second search space within the time window. Alternatively, the sleep unit may also be configured to enter a sleep state when no corresponding downlink response is received in the second search space within the time window.

[0539] The second PDSCH receiving unit 55 is configured to receive a second type of PDSCH according to the PDCCH received in the second search space.

[0540] In an exemplary embodiment of the present disclosure, the user equipment may also include: a resource determination unit, configured to determine the resources of the second type of PDSCH based on the resource information of the PDSCH contained in the PDCCH, the resource information of the PDSCH contained in the first type of PDSCH, or at least one set of PDSCH resource information configured by the base station in the RRC connection state, or to determine the resources of the second type of PDSCH based on the PRACH.

[0541] In an exemplary embodiment of the present disclosure, the second type of PDSCH may include at least one of the following: downlink data, uplink channel information for carrying ACK, uplink timing adjustment information, uplink scheduling information, and the first type of RNTI. Here, the second type of PDSCH is scrambled according to the first type of RNTI, and / or RA-RNTI, and / or cell ID, and / or a sequence determined by PRACH.

[0542] The feedback unit 56 is configured to demodulate the second type PDSCH and provide ACK feedback according to the demodulation result.

[0543] In an exemplary embodiment of the present disclosure, the user equipment may further include: a PDCCH monitoring unit configured to monitor the PDCCH in the second or third search space within a predetermined time window. Here, the predetermined time window may be based on any of the following as a starting point: the end symbol of the uplink channel for ACK feedback by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the uplink channel for ACK feedback by the user equipment is located, the end symbol of the PDSCH sent by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the PDSCH sent by the user equipment is located, the end symbol of the PUSCH sent by the user equipment, and the end position of the time slot / sub-time slot where the end symbol of the PUSCH sent by the user equipment is located.

[0544] The sleep unit 57 is configured to enter a sleep state when a predefined sleep condition is satisfied.

[0545] In an exemplary embodiment of the present disclosure, the user equipment may also include: an information receiving unit, configured to receive at least one of the following items sent by the base station within a predetermined time window: downlink control channel resource configuration information, PRACH configuration information, uplink channel configuration information of ACK feedback, scheduling information of the second type of PDSCH, scheduling information of PUSCH, transmission mode indication information, PRACH transmission trigger information, trigger information of a contention-based random access process, and indication information for entering a sleep state.

[0546] In an exemplary embodiment of the present disclosure, the sleep unit may also be configured to enter the sleep state when no PDCCH is received within a predetermined time window or when indication information for entering the sleep state is received.

[0547] In an exemplary embodiment of the present disclosure, the fallback unit is further configured to fall back to a contention-based random access procedure according to a received fallback indication or based on a detected fallback trigger condition. Here, the fallback trigger condition includes at least one of the following: uplink timing failure, receiving a PDCCH scheduling a second type of PDSCH but uplink timing failure, and not receiving a response within a predefined time window after sending a contention-free PRACH.

[0548] Figure 6 A block diagram of a user equipment according to another exemplary embodiment of the present disclosure is shown.

[0549] Reference Figure 6 The user equipment includes a third PDCCH receiving unit 61, a third PDSCH receiving unit 62, a feedback unit 63 and a sleeping unit 64.

[0550] The third PDCCH receiving unit 61 is configured to receive a predefined PDCCH in a third search space.

[0551] In an exemplary embodiment of the present disclosure, the third search space may be used to support the reception of a control channel for downlink transmission by a UE in an RRC idle / deactivated state. The third search space may be used to monitor a PDCCH that schedules a second type of PDSCH.

[0552] In an exemplary embodiment of the present disclosure, the parameters of the third search space are optionally configured, and if the parameters of the specific search space are not configured, the search space of the predefined purpose is used as the specific search space. Here, the third search space is determined according to user equipment specific RRC signaling, or the third search space is determined according to cell system information, or the third search space is determined according to user equipment specific parameters and common search space parameters.

[0553] The third PDSCH receiving unit 62 is configured to receive the second type PDSCH according to the PDCCH received in the third search space.

[0554] The feedback unit 63 is configured to perform ACK feedback according to the received downlink signal.

[0555] The sleep unit 64 is configured to enter a sleep state when a predefined sleep condition is satisfied.

[0556] Figure 7 A block diagram of a user equipment according to another exemplary embodiment of the present disclosure is shown.

[0557] Reference Figure 7 , the user equipment includes a signal receiving unit 71 and a feedback unit 72.

[0558] The signal receiving unit 71 is configured to receive a predefined downlink signal in a predefined downlink resource.

[0559] In an exemplary embodiment of the present disclosure, the predefined downlink resource is a predefined second-category PDSCH resource, which is configured by the base station when the user equipment is in an RRC connected state and is used for downlink transmission in an RRC idle / inactive state.

[0560] The feedback unit 72 is configured to perform ACK feedback according to the received downlink signal.

[0561] In an exemplary embodiment of the present disclosure, if the UE demodulates the PDSCH correctly, the UE feeds back ACK, and if the UE does not demodulate the PDSCH correctly, the UE does not feed back. Alternatively, the UE feeds back ACK or NACK according to the demodulation result of the PDSCH.

[0562] In an exemplary embodiment of the present disclosure, ACK and NACK may be carried by PRACH or PUCCH, or ACK may be carried by PUSCH.

[0563] In an exemplary embodiment of the present disclosure, the user equipment may further include: a transmission judgment unit configured to judge whether to send PUCCH according to whether the uplink timing is valid. If the uplink timing is valid, the PUCCH carrying ACK or NACK is sent according to the uplink timing, and if the uplink timing fails, the PUCCH is not sent; or, if the uplink timing is valid, the PUCCH carrying ACK or NACK is sent according to the uplink timing, and if the uplink timing fails, the PRACH is sent and the PUCCH is not sent.

[0564] In an exemplary embodiment of the present disclosure, after receiving a downlink signal (second type PDSCH), the PDCCH may be monitored in the third search space within a predetermined time window. Here, the predetermined time window may be based on any of the following as a starting point: the end symbol of the uplink channel for ACK feedback by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the uplink channel for ACK feedback by the user equipment is located, the end symbol of the PDSCH sent by the user equipment, the end position of the time slot / sub-time slot where the end symbol of the PDSCH sent by the user equipment is located, the end symbol of the PUSCH sent by the user equipment, and the end position of the time slot / sub-time slot where the end symbol of the PUSCH sent by the user equipment is located.

[0565] Figure 8 A block diagram of a user equipment according to another exemplary embodiment of the present disclosure is shown.

[0566] Reference Figure 8 The user equipment includes: a first PDCCH receiving unit 81, a first PDSCH receiving unit 82, a PRACH sending unit 83, a PDCCH monitoring unit 84, a second PDCCH receiving unit 85, a second PDSCH receiving unit 86, a feedback unit 87 and a sleeping unit 88.

[0567] The first PDCCH receiving unit 81 is configured to receive a predefined PDCCH in a first search space.

[0568] The first PDSCH receiving unit 82 is configured to receive a first-type PDSCH according to a PDCCH received in a first search space.

[0569] The PRACH transmitting unit 83 is configured to transmit the PRACH according to the first type PDSCH.

[0570] The PDCCH monitoring unit 84 is configured to monitor the PDCCH in a predefined second search space within a predetermined time window.

[0571] The second PDCCH receiving unit 85 is configured to receive the PDCCH in the second search space when monitoring the PDCCH within a predetermined time window.

[0572] The second PDSCH receiving unit 86 is configured to receive the second type PDSCH when the PDCCH received in the second search space indicates reception of the second type PDSCH.

[0573] The feedback unit 87 is configured to demodulate the second type PDSCH and perform ACK feedback according to the demodulation result.

[0574] The sleep unit 88 is configured to enter the sleep state when the PDCCH received in the second search space indicates to enter the sleep state, or enter the sleep state when the PDCCH is not monitored within a predetermined time window.

[0575] In addition, according to an exemplary embodiment of the present disclosure, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed, the steps of the downlink transmission method according to the present disclosure are implemented.

[0576] As an example, the computer-readable storage medium may carry one or more programs, and when the computer program is executed, the following steps may be implemented: receiving a predefined downlink signal in a predefined downlink resource, and performing ACK feedback according to the received downlink signal.

[0577] As an example, the computer-readable storage medium may carry one or more programs, and when the computer program is executed, the following steps may be implemented: receiving a predefined PDCCH in a predefined first search space, receiving a first type of PDSCH according to the PDCCH received in the first search space, sending a PRACH according to the first type of PDSCH, monitoring the PDCCH in a predefined second search space within a predetermined time window, determining whether the PDCCH is monitored within the predetermined time window, and if the PDCCH is monitored, receiving the monitored PDCCH in the second search space, and when the PDCCH received in the second search space is received, The system enters the sleep state when CH indicates entering the sleep state, receives the second type of PDSCH when the PDCCH received in the second search space indicates receiving the second type of PDSCH, receives the second type of PDSCH according to the PDCCH received in the second search space, demodulates the second type of PDSCH, performs HARQ-ACK feedback according to the demodulation result, and then jumps to the step of determining whether the PDCCH is monitored within the predetermined time window to determine again whether the PDCCH is monitored within the predetermined time window, until entering the sleep state when the PDCCH is not monitored within the predetermined time window, and directly enters the sleep state if the PDCCH is not monitored.

[0578] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In an embodiment of the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a computer program that may be used by or in conjunction with an instruction execution system, device or device. The computer program contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination thereof. The computer-readable storage medium may be contained in any device; it may also exist alone without being assembled into the device.

[0579] The above has been combined Figures 5 to 8 The downlink transmission device according to the exemplary embodiment of the present disclosure is described. Fig. 9 A computing device according to an exemplary embodiment of the present disclosure is described.

[0580] Fig. 9 A schematic diagram showing a computing device according to an exemplary embodiment of the present disclosure.

[0581] Reference Fig. 9 According to an exemplary embodiment of the present disclosure, a computing device 9 includes a memory 91 and a processor 92. The memory 91 stores a computer program. When the computer program is executed by the processor, the steps of the downlink transmission method according to the present disclosure are implemented.

[0582] As an example, when the computer program is executed by a processor, the following steps may be implemented: receiving a predefined downlink signal in a predefined downlink resource, and performing ACK feedback according to the received downlink signal.

[0583] As an example, when the computer program is executed by a processor, the following steps may be implemented: receiving a predefined PDCCH in a predefined first search space, receiving a first type of PDSCH according to the PDCCH received in the first search space, sending a PRACH according to the first type of PDSCH, monitoring a PDCCH in a predefined second search space within a predetermined time window, determining whether a PDCCH is monitored within the predetermined time window, receiving the monitored PDCCH in a second search space if the PDCCH is monitored, and entering a sleep state when the PDCCH received in the second search space indicates Enter the sleep state when the PDCCH received in the second search space indicates receiving the second type of PDSCH, receive the second type of PDSCH, receive the second type of PDSCH according to the PDCCH received in the second search space, demodulate the second type of PDSCH, perform HARQ-ACK feedback according to the demodulation result, and then jump to the step of determining whether the PDCCH is monitored within the predetermined time window to determine again whether the PDCCH is monitored within the predetermined time window, until entering the sleep state when the PDCCH is not monitored within the predetermined time window, and directly enter the sleep state if the PDCCH is not monitored.

[0584] Fig. 9 The computing device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0585] The above has been referred to Figures 1 to 9 The downlink transmission method performed by the user equipment and the user equipment according to the exemplary embodiments of the present disclosure are described. However, it should be understood that: Figures 5 to 8 The user equipment and its units shown in the figure may be configured as software, hardware, firmware or any combination of the above items to perform specific functions. Fig. 9 The computing device shown in is not limited to including the components shown above, but some components may be added or deleted as needed, and the above components may also be combined.

[0586] According to the downlink transmission method and user equipment performed by the exemplary embodiments of the present disclosure, by receiving a predefined downlink signal in a predefined downlink resource and performing ACK feedback according to the received downlink signal, downlink data transmission is achieved in the RRC idle or inactive state.

[0587] While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims.

Claims

1. A method performed by a terminal in a communication system, comprising: Sending a random access preamble to the base station on a physical random access channel PRACH; receiving a random access response RAR sent from the base station for the PRACH; sending a physical uplink control channel PUCCH having hybrid automatic repeat request HARQ-acknowledgement ACK information for the RAR to the base station, The time unit for sending the PUCCH is determined based on a first parameter related to the time unit of the PDSCH associated with the RAR, a second parameter determined based on a timing indicator field included in the RAR, and a third parameter determined based on the subcarrier spacing SCS of the physical uplink shared channel PUSCH scheduled by the RAR.

2. The method according to claim 1, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter and the third parameter.

3. The method according to claim 1, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the fourth parameter is determined based on the SCS of the PUCCH.

4. The method according to claim 1, wherein: The bit size of the timing indicator field is 3, and the second parameter is equal to one of 1 to 8.

5. The method according to claim 1, wherein: Based on the SCS of the PUSCH scheduled by the RAR being 15 kHz, the third parameter being 2, Wherein, based on the SCS of the PUSCH scheduled by the RAR being 30kHz, the third parameter is 3, Wherein, the SCS of the PUSCH scheduled by the RAR is 60kHz, the third parameter is 4, and Among them, the SCS of the PUSCH scheduled by the RAR is 120kHz, and the third parameter is 6.

6. The method according to claim 1, wherein: The PUCCH with HARQ-ACK information for the RAR is sent in response to the RAR including a medium access control MAC protocol data unit PDU corresponding to a successful RAR.

7. The method according to claim 1, wherein: The first parameter related to the time unit of the PDSCH associated with the RAR is the time unit where the PDSCH is located.

8. The method according to claim 7, wherein: The time unit of the PDSCH associated with the RAR is an uplink time unit.

9. The method according to any one of claims 1 to 8, wherein: The time unit is a time slot.

10. A method performed by a base station, the method comprising: Receiving a random access preamble from a terminal on a physical random access channel PRACH; Sending a random access response RAR for the PRACH to the terminal; receiving a physical uplink control channel PUCCH having hybrid automatic repeat request HARQ-acknowledgement ACK information for the RAR from the terminal; The time unit for sending the PUCCH is determined based on a first parameter related to the time unit of the PDSCH associated with the RAR, a second parameter determined based on a timing indicator field included in the RAR, and a third parameter determined based on the subcarrier spacing SCS of the physical uplink shared channel PUSCH scheduled by the RAR.

11. The method according to claim 10, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter and the third parameter.

12. The method according to claim 10, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the fourth parameter is determined based on the SCS of the PUCCH.

13. The method according to claim 10, wherein: The bit size of the timing indicator field is 3, and the second parameter is equal to one of 1 to 8.

14. The method according to claim 10, wherein: Based on the SCS of the PUSCH scheduled by the RAR being 15 kHz, the third parameter being 2, Wherein, based on the SCS of the PUSCH scheduled by the RAR being 30kHz, the third parameter is 3, Wherein, the SCS of the PUSCH scheduled by the RAR is 60kHz, the third parameter is 4, and Among them, the SCS of the PUSCH scheduled by the RAR is 120kHz, and the third parameter is 6.

15. The method according to claim 10, wherein: The PUCCH with HARQ-ACK information for the RAR is sent in response to the RAR including a medium access control MAC protocol data unit PDU corresponding to a successful RAR.

16. The method according to claim 10, wherein: The first parameter related to the time unit of the PDSCH associated with the RAR is the time unit where the PDSCH is located.

17. The method according to claim 16, wherein: The time unit of the PDSCH associated with the RAR is an uplink time unit.

18. The method according to any one of claims 10 to 17, wherein: The time unit is a time slot.

19. A terminal in a communication system, the terminal comprising: Transceiver; as well as The controller is configured as: Sending a random access preamble to the base station on a physical random access channel PRACH; receiving a random access response RAR sent from the base station for the PRACH; Sending a physical uplink control channel PUCCH having hybrid automatic repeat request HARQ-acknowledgement ACK information for the RAR to the base station; The time unit for sending the PUCCH is determined based on a first parameter related to the time unit of the PDSCH associated with the RAR, a second parameter determined based on a timing indicator field included in the RAR, and a third parameter determined based on the subcarrier spacing SCS of the physical uplink shared channel PUSCH scheduled by the RAR.

20. The terminal according to claim 19, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter and the third parameter.

21. The terminal according to claim 19, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the fourth parameter is determined based on the SCS of the PUCCH.

22. The terminal according to claim 19, wherein: The bit size of the timing indicator field is 3, and the second parameter is equal to one of 1 to 8.

23. The terminal according to claim 19, wherein: Based on the SCS of PUSCH scheduled by RAR is 15kHz, the third parameter is 2, Wherein, based on the SCS of the PUSCH scheduled by the RAR being 30kHz, the third parameter is 3, Wherein, the SCS of the PUSCH scheduled by the RAR is 60kHz, the third parameter is 4, and Among them, the SCS of the PUSCH scheduled by the RAR is 120kHz, and the third parameter is 6.

24. The terminal according to claim 19, wherein: In response to the RAR including a medium access control MAC protocol data unit (PDU) corresponding to a successful RAR, a PUCCH with HARQ-ACK information for the RAR is sent.

25. The terminal according to claim 19, wherein: The first parameter related to the time unit of the PDSCH associated with the RAR is the time unit where the PDSCH is located.

26. The terminal according to claim 25, wherein: The time unit of the PDSCH associated with the RAR is an uplink time unit.

27. The terminal according to any one of claims 19 to 26, wherein: The time unit is a time slot.

28. A base station in a communication system, the base station comprising: Transceiver; as well as The controller is configured as: Receiving a random access preamble from a terminal on a physical random access channel PRACH; Sending a random access response RAR for the PRACH to the terminal; receiving a physical uplink control channel PUCCH having hybrid automatic repeat request HARQ-acknowledgement ACK information for the RAR from the terminal; The time unit for sending the PUCCH is determined based on a first parameter related to the time unit of the PDSCH associated with the RAR, a second parameter determined based on a timing indicator field included in the RAR, and a third parameter determined based on the subcarrier spacing SCS of the physical uplink shared channel PUSCH scheduled by the RAR.

29. The base station according to claim 28, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter and the third parameter.

30. The base station according to claim 28, wherein: The time unit for sending the PUCCH is determined based on the sum of the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the fourth parameter is determined based on the SCS of the PUCCH.

31. The base station according to claim 28, wherein: The bit size of the timing indicator field is 3, and the second parameter is equal to one of 1 to 8.

32. The base station according to claim 28, wherein: Based on the SCS of the PUSCH scheduled by the RAR being 15KHz, the third parameter is 2, Wherein, based on the SCS of the PUSCH scheduled by the RAR being 30kHz, the third parameter is 3, Wherein, the SCS of the PUSCH scheduled by the RAR is 60kHz, the third parameter is 4, and Among them, the SCS of the PUSCH scheduled by the RAR is 120kHz, and the third parameter is 6.

33. The base station according to claim 28, wherein: The first parameter related to the time unit of the PDSCH associated with the RAR is the time unit where the PDSCH is located.

34. The base station according to claim 33, wherein: The time unit of the PDSCH associated with the RAR is an uplink time unit.

35. The base station according to any one of claims 28 to 33, wherein: The time unit is a time slot.

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