Communication device and communication method for random access

Abstract

The present disclosure provides an apparatus and method for establishing random access. The apparatus includes a terminal, the terminal including a circuit for generating a first random access preamble and a transmitter, the transmitter transmitting the first random access preamble to a base station on a first physical random access channel (PRACH) opportunity (RO) among a plurality of RO candidates, the plurality of RO candidates being determined based on PRACH configuration information received from the base station, wherein the first RO is allocated within a first frequency region, the first frequency region being equal to a first subband in which a listen-before-talk (LBT) procedure is performed at the terminal.

Description

Technical Field

[0001] The following disclosure relates to a communication device and a communication method for random access in fifth generation (5G) communications, and more particularly to a communication device and a communication method for establishing a random access channel (RACH) procedure in new radio (NR) operating in an unlicensed band. Background Art

[0002] In the standardization of 5G, the 3rd Generation Partnership Project (3GPP) has discussed NR access technology, which does not necessarily have backward compatibility with Long Term Evolution (LTE) / LTE-Advanced technology. In NR, like LTE License Assisted Access (LTE-LAA), it is expected to operate in unlicensed bands (such as NR-U).

[0003] In unlicensed bands, a listen-before-talk (LBT) procedure is required for channel access depending on the country, frequency, and conditions. However, there has been insufficient discussion on communication devices and communication methods for establishing a RACH procedure in unlicensed bands subject to LBT.

[0004] Therefore, there is a need for a communication device and method that can address the above-mentioned shortcomings to ensure efficient and reliable communication for establishing a RACH procedure in NR operating in an unlicensed band. Moreover, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the background of the present disclosure. Summary of the Invention

[0005] One non-limiting and exemplary embodiment facilitates establishing a random access channel (RACH) procedure in an efficient and reliable manner.

[0006] In one aspect, the technology disclosed herein provides a communications device. The communications device is a terminal. The terminal includes: circuitry for generating a first random access preamble; and a transmitter for transmitting the first random access preamble to a base station on a first physical random access channel (PRACH) opportunity (RO) among a plurality of RO candidates. The plurality of RO candidates are determined based on PRACH configuration information received from the base station. In this aspect, the first RO is allocated within a first frequency region that is equal to a first subband in which a listen-before-talk (LBT) procedure is performed at the terminal.

[0007] In another aspect, the technology disclosed herein provides a communications device. The communications device is a base station. The base station includes: circuitry for determining a PRACH configuration, the PRACH configuration including multiple RO candidates; and a receiver for receiving a first random access preamble from a terminal on a first RO among the multiple RO candidates. In this aspect, the first RO is allocated within a first frequency region, the first frequency region being equal to a first subband in which a LBT process is performed at the terminal.

[0008] In another aspect, the technology disclosed herein provides a communication method. The communication method includes generating a first random access preamble at a terminal; and sending the first random access preamble from the terminal to a base station on a first RO among a plurality of RO candidates, the plurality of RO candidates being determined based on PRACH configuration information received from the base station, wherein the first RO is allocated within a first frequency region, the first frequency region being equal to a first subband in which a LBT process is performed at the terminal.

[0009] On the other hand, the technology disclosed herein provides another communication method. The communication method includes: determining, at a base station, a PRACH configuration, the PRACH configuration including multiple RO candidates; and receiving, at the base station, a first random access preamble code on a first RO among the multiple RO candidates, wherein the first RO is allocated within a first frequency region, the first frequency region being equal to a subband in which a LBT process is performed at a terminal.

[0010] On the other hand, the technology disclosed herein provides a communication device, comprising: a receiver, which receives a first synchronization signal block SSB from a base station and receives physical random access channel PRACH configuration information from the base station; and a transmitter, which is coupled to the receiver and sends a first random access preamble code to the base station on a first RO or a second RO of a plurality of physical random access channel PRACH opportunity RO candidates corresponding to the SSB index of the received first SSB, wherein the plurality of RO candidates corresponding to the SSB index are allocated in a plurality of frequency regions according to an allocation pattern based on the PRACH configuration information, wherein, at the same time, the first RO of the plurality of RO candidates is allocated in a first frequency region, and the second RO of the plurality of RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein, Each of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal, wherein the PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and wherein the positions of the RO candidates on the first frequency region and the second frequency region are determined based at least on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, wherein the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

[0011] On the other hand, the technology disclosed herein provides a communication method performed by a communication device, including: receiving a first synchronization signal block SSB from a base station, and receiving physical random access channel PRACH configuration information from the base station; and sending a first random access preamble code to the base station on a first RO or a second RO among a plurality of physical random access channel PRACH opportunity RO candidates corresponding to the SSB index of the received first SSB, wherein the plurality of RO candidates corresponding to the SSB index are allocated within a plurality of frequency regions according to an allocation pattern based on the PRACH configuration information, wherein, at the same time, the first RO among the plurality of RO candidates is allocated within a first frequency region, and the second RO among the plurality of RO candidates is allocated within a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein the plurality of Each of the frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal, wherein the PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and wherein the positions of the RO candidates on the first frequency region and the second frequency region are determined based at least on msg1-FDM, which is common in the first frequency region and the second frequency region and is included in the PRACH configuration information, and wherein the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at one time.

[0012] On the other hand, the technology disclosed herein provides a base station, comprising: a transmitter, which transmits a first synchronization signal block SSB and physical random access channel PRACH configuration information; and a receiver, which receives a first random access preamble code from a communication device on a first RO or a second RO among a plurality of PRACH opportunity RO candidates corresponding to an SSB index of the first SSB, wherein the plurality of RO candidates corresponding to the SSB index are allocated within a plurality of frequency regions according to an allocation pattern based on the PRACH configuration information, wherein, at the same time, a first RO among the plurality of RO candidates is allocated within a first frequency region, and a second RO among the plurality of RO candidates is allocated within a second frequency region, the second frequency region being different from the first frequency region along a frequency axis, wherein each of the plurality of frequency regions is allocated within a first frequency region. The domain is equal to the subband in which the listen-before-talk LBT process is performed at the terminal, wherein the PRACH configuration information is configured according to each of the multiple frequency regions and includes prach-ConfigurationIndex, which indicates the PRACH time resources for the first RO and the second RO corresponding to the SSB index, and wherein the positions of the RO candidates on the first frequency region and the second frequency region are determined based at least on msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at one time.

[0013] On the other hand, the technology disclosed herein provides a communication method performed by a base station, including: sending a first synchronization signal block SSB and physical random access channel PRACH configuration information; and receiving a first random access preamble code from a communication device on a first RO or a second RO among a plurality of physical random access channel PRACH opportunity RO candidates corresponding to the SSB index of the first SSB, wherein the plurality of RO candidates corresponding to the SSB index are allocated within a plurality of frequency regions according to an allocation pattern based on the PRACH configuration information, wherein, at the same time, the first RO among the plurality of RO candidates is allocated within a first frequency region, and the second RO among the plurality of RO candidates is allocated within a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each of the plurality of frequency regions Frequency regions are equal to subbands in which a listen-before-talk (LBT) process is performed at a terminal, wherein the PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and wherein the positions of the RO candidates on the first frequency region and the second frequency region are determined based at least on msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, wherein the msg1-FDM indicates the number of frequency-division multiplexed ROs of each of the first frequency region and the second frequency region at one time.

[0014] On the other hand, the technology disclosed herein provides an integrated circuit, comprising: a circuit, controlling: receiving a first synchronization signal block SSB from a base station, and receiving physical random access channel PRACH configuration information from the base station; and sending a first random access preamble code to the base station on a first RO or a second RO among a plurality of physical random access channel PRACH opportunity RO candidates corresponding to the SSB index of the received first SSB, wherein the plurality of RO candidates corresponding to the SSB index are allocated in a plurality of frequency regions according to an allocation pattern based on the PRACH configuration information, wherein, at the same time, the first RO among the plurality of RO candidates is allocated in a first frequency region, and the second RO among the plurality of RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein the plurality of frequency regions are Each frequency region in the rate region is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal, wherein the PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and wherein the positions of the RO candidates on the first frequency region and the second frequency region are determined based at least on msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, wherein the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at one time.

[0015] On the other hand, the technology disclosed herein provides an integrated circuit, comprising: a circuit that controls: sending a first synchronization signal block SSB and physical random access channel PRACH configuration information; and receiving a first random access preamble code from a communication device on a first RO or a second RO among a plurality of physical random access channel PRACH opportunity RO candidates corresponding to an SSB index of the first SSB, wherein the plurality of RO candidates corresponding to the SSB index are allocated in a plurality of frequency regions according to an allocation pattern based on the PRACH configuration information, wherein, at the same time, a first RO among the plurality of RO candidates is allocated in a first frequency region, and a second RO among the plurality of RO candidates is allocated in a second frequency region, the second frequency region being different from the first frequency region along a frequency axis, wherein each of the plurality of frequency regions Frequency regions are equal to subbands in which a listen-before-talk (LBT) process is performed at a terminal, wherein the PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and wherein the positions of the RO candidates on the first frequency region and the second frequency region are determined based at least on msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, wherein the msg1-FDM indicates the number of frequency-division multiplexed ROs of each of the first frequency region and the second frequency region at one time.

[0016] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof.

[0017] Other benefits and advantages of the disclosed embodiments will become apparent from the description and drawings. Benefits and / or advantages can be obtained individually from the various embodiments and features of the description and drawings, and not all of them need to be provided in order to obtain one or more such benefits and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments of the present disclosure will be better understood and apparent to those skilled in the art through the following written description, which is given by way of example only, taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 A signal flow is shown according to an exemplary method 100, which includes a four-step random access channel (RACH) procedure between a base station and a terminal.

[0020] Figure 2a An example of a physical random access channel (PRACH) opportunity (RO) defined in the time and frequency domains and used for MSG1 transmission in a 4-step RACH procedure in an unlicensed carrier having more than one frequency region is shown. In this example, the RO is distributed across more than one frequency region and is used to establish a single RACH procedure (interchangeably referred to as a single RACH procedure).

[0021] Figure 2b Another example of an RO defined in the time and frequency domains and used for MSG1 transmission in a 4-step RACH procedure in an unlicensed carrier having more than one frequency region is shown. In this example, the RO is distributed in more than one frequency region and is used to establish multiple RACH procedures (interchangeably referred to as multi-RACH procedures) in parallel.

[0022] Figure 3a An example of PRACH configuration in a licensed carrier according to NR technology is shown. As shown in the example, PRACH is configured for each carrier.

[0023] Figure 3b Shows that when Figure 3a The PRACH configuration of the NR technology shown in Figure 1 is used in the scenario where RO is not fully utilized when it is used in an unlicensed carrier.

[0024] Figure 4a A schematic example of a base station for establishing a RACH procedure according to an embodiment is shown. In this example, the base station may be interchangeably referred to as an ngNodeB (gNB).

[0025] Figure 4b FIG. 4 is a schematic diagram of a terminal for establishing a RACH procedure according to an embodiment. In this example, the terminal may be interchangeably referred to as a user equipment.

[0026] Figure 5 An example of a PRACH configuration for maximizing RO availability within a RACH procedure in an unlicensed carrier according to various embodiments of the present disclosure is shown. As shown in the example, the PRACH is configured per frequency region in a carrier.

[0027] Figure 6 Describes how Figure 5 In this embodiment of the PRACH configuration, the correspondence of SSBs to ROs (interchangeably referred to as SSB to RO mapping or SSB to RO association) is performed separately for each frequency region configured with PRACH.

[0028] Figure 7a Shown as Figure 5Another embodiment of PRACH configuration is shown. In this embodiment of PRACH configuration, the correspondence between SSB and RO is performed on multiple frequency regions configured with PRACH.

[0029] Figure 7b Shown as Figure 7a An alternative embodiment of a PRACH configuration is shown, wherein the correspondence between SSBs and ROs is performed on multiple frequency regions according to an alternative rule for the correspondence between SSBs and ROs.

[0030] Figure 7c Shown as Figure 7a and Figure 7b An alternative embodiment of a PRACH configuration is shown, in which the correspondence of SSBs to ROs is performed on multiple frequency regions according to an alternative rule for the correspondence of SSBs to ROs.

[0031] Figure 7d Shown as Figure 7a 、 7b and an alternative embodiment of the PRACH configuration shown in 7c, wherein the correspondence between SSB and RO is performed on multiple frequency regions according to an alternative rule for the correspondence between SSB and RO.

[0032] Figure 7e Shown as Figure 7a 、 7b , 7c and 7d are another embodiment of the PRACH configuration, wherein the correspondence between SSB and RO is performed on multiple frequency regions according to another rule of correspondence between SSB and RO.

[0033] Figure 8 Shown according to Figures 5 to 7e The various illustrated embodiments may be implemented as another illustrative example of a base station establishing a RACH procedure in an unlicensed carrier.

[0034] Figure 9 Shown according to Figures 5 to 7e The various embodiments shown may be implemented as another illustrative example of a terminal establishing a RACH procedure in an unlicensed carrier.

[0035] Skilled technicians will understand that the elements in the figures are shown for simplicity and clarity and are not necessarily depicted to scale. For example, the sizes of some elements in the diagrams, block diagrams, or flow charts may be exaggerated relative to other elements to help improve understanding of the present embodiment. DETAILED DESCRIPTION

[0036] Some embodiments of the present disclosure will be described, by way of example only, with reference to the accompanying drawings, in which like reference numerals and characters indicate like elements or equivalents.

[0037] In the following paragraphs, certain exemplary embodiments are explained with reference to a base station and a terminal for establishing a RACH procedure in a 5G NR communication system. The 5G NR communication system may be an NR independent system. The NR independent system may operate in a licensed carrier, an unlicensed carrier, or a licensed carrier and an unlicensed carrier. The RACH procedure is triggered by an event such as an initial access procedure from a user equipment (interchangeably referred to as a UE or terminal) when the terminal is turned on but does not have any established radio resource control (RRC) connection (i.e., RRC_IDLE), an RRC connection re-establishment procedure, a handover procedure, a beam failure recovery, etc. The RACH procedure is contention-based or contention-free. The contention-based RACH procedure may be a four-step RACH procedure or a two-step RACH procedure. The contention-free RACH procedure is basically a two-step procedure.

[0038] Figure 1 Signal flow is depicted according to an exemplary method 100, which includes a four-step RACH procedure between a base station 102 and a terminal 104.

[0039] exist Figure 1 In the exemplary method 100, the base station 102 is an ngNodeB (gNB). Those skilled in the art will appreciate that the base station 102 may also be an ng-eNB, which is a node that provides Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA) user plane and control plane protocol termination towards the terminal and is connected to the 5GC via an NG interface.

[0040] like Figure 1 As shown, in step 106, base station 102 periodically sends synchronization signal blocks (SSBs) and remaining minimum system information (RMSI) to terminal 104. RMSI includes information about the PRACH configuration determined by base station 102 (interchangeably referred to as PRACH configuration information). The PRACH configuration includes time and frequency resources that define various ROs in the time and frequency domains so that terminals that can communicate with base station 102, including terminal 104, can establish corresponding RACH procedures with base station 102. Each SSB sent from base station 102 to terminal 104 is associated with one or more ROs. Therefore, in step 106, terminal 104 receives the SSB and RMSI from base station 102.

[0041] At step 108, the terminal 104 transmits a random access preamble (interchangeably referred to as a PRACH preamble, shown as MSG1) on the RO to the base station 102. The RO is associated with one of the SSBs transmitted in step 106 that is selected / detected by the terminal 104 as having good quality. In an embodiment, another terminal may accidentally transmit the same PRACH preamble on the RO, or transmit the same PRACH preamble on another RO associated with the same SSB as the RO (shown at step 108). Therefore, at step 108, the base station 102 receives MSG1 from the terminal 104 on the RO. The base station 102 may also receive the same MSG1 from another terminal on the RO or on another RO associated with the same SSB as the RO.

[0042] At step 110, base station 102 is configured to transmit a random access response (shown as MSG2) during a random access response (RAR) window in response to receiving a PRACH preamble from terminal 104 and / or another terminal. The configuration of the RAR window is determined by the base station and included in system information. MSG2 includes the index of the PRACH preamble received by base station 102, a timing advance command, and an uplink grant (shown as MSG3) for the scheduled transmission. Therefore, at step 110, terminal 104 is also configured to receive MSG2 during the RAR window in response to the transmission of MSG1 to base station 102.

[0043] In step 112, if the index of the PRACH preamble transmitted by terminal 104 in step 108 matches the index of the PRACH preamble received by base station 102 in MSG2, terminal 104 is further configured to transmit MSG3 to base station 102 in an uplink grant in response to receipt of MSG2 from base station 102. Otherwise, terminal 104 determines that the RACH procedure between terminal 104 and base station 102 was unsuccessful and may restart another RACH procedure. MSG3 includes an identifier of terminal 104. In an embodiment, another terminal having a transmitted PRACH preamble index that matches the index of the PRACH preamble in MSG2 may also transmit MSG3 to base station 102 in an uplink grant. Therefore, in step 112, base station 102 is configured to receive MSG3 from terminal 104 and / or another terminal in an uplink grant in response to the transmission of MSG2.

[0044] At step 114, base station 102 is configured to transmit a contention resolution (shown as MSG4) in response to receiving MSG3 from terminal 104 and / or another terminal. MSG4 includes the identifier of the terminal that won the contention. Therefore, at step 114, terminal 104 is configured to receive MSG4 from base station 102 in response to the transmission of MSG3 to base station 102. If the identifier of terminal 104 matches the identifier of the winning terminal in MSG4, terminal 104 determines that the RACH procedure between terminal 104 and base station 102 was successful. Otherwise, terminal 104 determines that the RACH procedure between terminal 104 and base station 102 was unsuccessful and may restart another RACH procedure.

[0045] The above steps 108, 110, 112 and 114 of exemplary method 100 form a 4-step RACH process. Figure 1 As shown, before the 4-step RACH procedure, the RO is determined by the base station 102 and notified to the terminal 104 in the PRACH configuration information sent in the RMSI in step 106.

[0046] According to the present disclosure, when a 5G NR communication system operates in an unlicensed carrier, the carrier may have a bandwidth that is a multiple of 20 MHz. The frequency range of the carrier may be divided into one or more frequency regions. Each frequency region is equal to a frequency subband (interchangeably referred to as an LBT subband) in which an LBT process is performed. The frequency region or LBT subband may have a size of 20 MHz.

[0047] In such Figure 1In the illustrated four-step RACH procedure, before transmitting MSG1 or MSG3, terminal 104 may need to perform a LBT procedure to determine whether the subband in which MSG1 or MSG3 will be transmitted is idle. If the subband is deemed idle (i.e., LBT succeeded), terminal 104 transmits MSG1 or MSG3. If the subband is deemed busy (i.e., LBT failed), terminal 104 does not transmit MSG1 or MSG3. Similarly, base station 102 may also need to perform an LBT procedure before transmitting MSG2 or MSG4. The reduced transmission opportunities for MSG1, MSG2, MSG3, and MSG4 due to LBT failures at terminal 104 or base station 102 will reduce the efficiency of the four-step RACH procedure. Therefore, it is necessary to develop a mechanism to increase the transmission opportunities for MSG1, MSG2, MSG3, and MSG4 to address LBT failures in the four-step RACH procedure. For example, to increase MSG1 transmission opportunities in the case of carriers that include more than one frequency region, at a given moment, more than one RO may be distributed across more than one frequency region for PRACH preamble transmission. In this case, terminal 104 can simultaneously perform multiple LBT processes in multiple subbands. Even if one of the multiple LBT processes fails, another one of the multiple LBT processes may succeed. In this way, MSG1 transmission opportunities in the event of an LBT failure are multiplied.

[0048] More than one RO distributed in more than one frequency region in a carrier may be used to send a PRACH preamble to establish a single RACH process, or alternatively, to send different PRACH preambles to establish multiple RACH processes in a carrier.

[0049] Figure 2a shows an example of a RO defined in the time and frequency domains. Figure 1 A 4-step RACH procedure in an unlicensed carrier with more than one frequency region is shown for MSG1 transmission. In this example, ROs are distributed in more than one frequency region and are used to establish a single RACH procedure.

[0050] like Figure 2a As shown, the carrier's frequency range is divided into two frequency regions: a first frequency region and a second frequency region. It can be seen that the number of frequency regions in a carrier depends on the carrier bandwidth and the size of the LBT subband. For example, if the carrier has an 80 MHz bandwidth and the LBT subband is 20 MHz, the carrier has four frequency regions. If the carrier has an 80 MHz bandwidth and the LBT subband is 40 MHz, the carrier has two frequency regions.

[0051] exist Figure 2aIn the example shown, at a certain moment, two ROs can be used by the terminal to perform PRACH preamble code transmission. For example, at time t1, two ROs (e.g., RO1 and RO2) located in the first frequency region and the second frequency region, respectively, can be used by the terminal to send a PRACH preamble code to the base station.

[0052] In a single RACH process, only a single PRACH preamble is transmitted. In this regard, the terminal selects RO1 and RO2, both located in the first frequency region and the second frequency region, which are both available for PRACH preamble transmission at time t1, and performs an LBT process on each frequency region / subband. If the LBT process is successful in both frequency regions, the terminal can randomly select an RO from RO1 and RO2 and transmit the PRACH preamble on that RO. Figure 2a In the example of , the LBT process in the first frequency region succeeds, but the LBT process in the second frequency region fails. Therefore, the terminal sends a PRACH preamble code (ie, MSG1) to the base station on RO1.

[0053] After receiving the PRACH preamble from the terminal, the base station performs the LBT in one of the two frequency regions where the LBT is successful (e.g., Figure 2a The random access response (ie, Figure 1 The configuration of the RAR window is determined by the base station and indicated in the system information so that the terminal is aware of the possible RAR window and is ready to receive the random access response. MSG2 may include more than one uplink grant for the scheduled transmission (i.e., MSG3) in the first frequency region or the second frequency region or both. Figure 2b In the example of , MSG2 includes an uplink grant UG1 in the first frequency region and an uplink grant UG2 in the second frequency region.

[0054] In case MSG2 is received at the terminal, the terminal may perform an LBT procedure on each frequency region / sub-band containing an uplink grant for MSG3 transmission at time t2. Figure 2a In the example shown in FIG1 , the LBT process for the second frequency region succeeds, while the LBT process for the first frequency region fails. Therefore, the terminal sends MSG3 on the uplink grant UG2 to the base station.

[0055] In response to MSG3, the base station uses one of the two frequency regions where LBT is successful (e.g., Figure 2aThe UE 104 receives a downlink allocation in the first frequency region (shown in FIG. 1 ), and sends a contention resolution message (i.e., MSG4) to the UE 104 to complete the 4-step RACH procedure. The downlink allocation is predetermined by the base station and indicated in the downlink control information (DCI) so that the UE is aware of the possible downlink allocation and is prepared to receive contention resolution.

[0056] Figure 2b Another example of RO defined in the time and frequency domains and used for MSG1 transmission in a 4-step RACH procedure in an unlicensed carrier with more than one frequency region is shown. Figure 2b In the example shown, ROs are distributed in more than one frequency region and are used to establish multiple RACH procedures.

[0057] Similar to Figure 2a , Figure 2b The frequency range of a carrier in a 10-MHz band is divided into two frequency regions: a first frequency region and a second frequency region. The number of frequency regions in a carrier depends on the carrier bandwidth and the size of the LBT subband. For example, if the carrier has an 80 MHz bandwidth and the LBT subband is 20 MHz, there are four frequency regions in the carrier.

[0058] exist Figure 2b In the example shown in FIG1 , at a certain moment, two ROs can be used by the terminal to perform PRACH preamble transmission. For example, at time t1, RO1 and RO2, located in the first frequency region and the second frequency region, respectively, can be used by the terminal to send different PRACH preambles to the base station to establish multiple RACH processes in parallel. It is understood that if the carrier has more frequency regions, the terminal may be able to send more PRACH preambles at a certain moment.

[0059] exist Figure 2b In the multi-RACH process in , at time t1, the terminal selects RO1 and RO2 located in the first frequency region and the second frequency region that can be used for PRACH preamble code transmission, and performs the LBT process in each frequency region.

[0060] exist Figure 2b In the example shown in FIG, the LBT process in both frequency regions is successful. Therefore, the terminal can send different PRACH preamble codes (ie, MSG1a and MSG1b) to the base station on RO1 and RO2 respectively to establish two parallel RACH processes.

[0061] It is possible that even if the LBT process may not be successful in all frequency regions, a multi-RACH process may still occur. For example, if a carrier has more than two frequency regions (for example, three frequency regions) and the LBT process is successful in some (for example, two) frequency regions, the terminal can send different PRACH preambles on the RO in the frequency region where the LBT is successful to establish a multi-RACH process.

[0062] After receiving different PRACH preambles from the terminal on RO1 and RO2, the base station returns two random access responses (i.e., MSG2a and MSG2b) during the RAR window of the first frequency region where LBT is successful or the second frequency region where LBT is successful. Figure 2b In the case where LBT in the two frequency regions shown is successful, the base station returns MSG2a and MSG2b, respectively, during the RAR window in each of the two frequency regions. The configuration of the RAR window is determined by the base station and indicated in the system information so that the terminal is aware of the possible RAR windows and is ready to receive the random access response. MSG2a in response to MSG1a includes one or more uplink grants for the scheduled transmission MSG3a in the first frequency region or the second frequency region or both. MSG2b in response to MSG1b includes one or more uplink grants for the scheduled transmission MSG3b in the first frequency region or the second frequency region or both. In Figure 2b In the example of , MSG2a includes an uplink grant UG1 for MSG3a transmission in the first frequency region, and MSG2b includes an uplink grant UG2 for MSG3b transmission in the second frequency region.

[0063] When the terminal receives MSG2a and MSG2b, the terminal may perform an LBT process on each frequency region / sub-band containing uplink grants for transmission of MSG3a and MSG3b at time t2. Figure 2b In the example shown in FIG, the LBT process in both frequency zones is successful. Therefore, the terminal sends MSG3a and MSG3b to the base station on UG1 and UG2, respectively.

[0064] After receiving MSG3a and MSG3b from the terminal, the base station returns two contention resolutions (i.e., MSG4a and MSG4b) in the downlink assignment in the first frequency region where LBT is successful or in the second frequency region where LBT is successful. Alternatively, in the case where LBT is successful in both frequency regions, the base station returns MSG4a and MSG4b in the downlink assignment in each of the two frequency regions, respectively. The downlink allocation is determined by the base station and indicated in the DCI so that the terminal is aware of the possible downlink allocation and is ready to receive contention resolution. Figure 2bIn the example of FIG. 4 , the base station transmits MSG 4 a in a downlink allocation in a first frequency region, and transmits MSG 4 b in a downlink allocation in a second frequency region.

[0065] By dividing the frequency range of the carrier into multiple frequency regions, ROs can be distributed on different frequency regions in the carrier, thereby significantly improving the transmission opportunity of MSG1 against LBT failure in a single RACH process or multiple RACH processes.

[0066] As mentioned above, the RO is determined by the base station based on the time and frequency resources in the PRACH configuration so that the terminal and the base station can establish their own RACH processes. Figure 1 As shown, in step 102, information on PRACH configuration (interchangeably referred to as PRACH configuration information) is sent from the base station to the terminal in RMSI.

[0067] Figure 3a An example of PRACH configuration in a licensed carrier according to NR technology with PRACH configured per carrier is shown.

[0068] The time resource of RO is interchangeably referred to as PRACH time resource. In RMSI, PRACH time resource is indicated by a parameter according to the higher layer protocol. For example, the parameter may be prach-ConfigurationIndex, which specifies the preamble format, the time position of the PRACH slot, the number of time-division multiplexed ROs within the PRACH slot (i.e. ) and the duration of each RO, etc. Figure 3a In the example, is 2, and the time positions of the PRACH slots respectively indicate four PRACH slots in the PRACH configuration, namely, PRACH slot 0, PRACH slot 1, PRACH slot 2, and PRACH slot 3.

[0069] The frequency resources used for RO are interchangeably referred to as PRACH frequency resources. PRACH frequency resources are indicated by multiple parameters. Each frequency-division multiplexed RO in a time instant has a frequency resource index n RA , where n RA ∈{0,1,…,M-1}, and according to the higher layer protocol, M is equal to the parameter msg1-FDM. According to the higher layer protocol, the starting position of the RO in the frequency domain is indicated by the parameter msg1-FrequencyStart. Starting from the lowest frequency, within the effective uplink bandwidth part, the ROs of the frequency division multiplexing within a time are numbered in ascending order.

[0070] exist Figure 3aThe correspondence between SSB and RO is shown in the PRACH configuration of . The correspondence between SSB and RO can be interchangeably referred to as SSB-RO association or SSB-RO mapping. The correspondence between SSB and RO has a period that depends on the PRACH configuration period and the number of SSBs actually transmitted in the carrier.

[0071] If the parameter SSB-perRACH-Occasion according to the higher layer protocol has a value less than 1, one SSB is mapped to consecutive ROs of 1 / SSB-perRACH-Occasion. Figure 3a As shown in , the parameter SSB-perRACH-Occasion has a value of 1 / 4. Figure 3a In the example shown in Figure 1, one SSB is mapped to four consecutive ROs.

[0072] exist Figure 3a In the SSB to RO correspondence shown, the SSB index is mapped to the RO in the following order:

[0073] (1) In ascending order of frequency resource index used for frequency division multiplexing RO;

[0074] (2) in ascending order of the time resource index of the time division multiplexed RO within the PRACH time slot; and

[0075] (3) In ascending order of PRACH slot index.

[0076] Figure 3b Shows that when Figure 3a The shown NR technology PRACH configuration is used in an unlicensed carrier when RO is not fully utilized.

[0077] As described above, an unlicensed carrier may contain one or more frequency regions, depending on the carrier bandwidth and the size of the LBT subband. If a carrier has more than one frequency region, some ROs may be allocated across two adjacent frequency regions within the carrier. If an LBT failure occurs in one of the two adjacent frequency regions at a given moment, the ROs allocated across the two adjacent frequency regions corresponding to that moment cannot be used for PRACH preamble transmission.

[0078] exist Figure 3b In the example of , the carrier has two frequency regions, namely the first frequency region and the second frequency region. Figure 3b The RO enclosed by the dotted circle in is allocated across the first frequency region and the second frequency region. If LBT fails in the first frequency region or the second frequency region at time t1, the RO with the line fill pattern cannot be used.

[0079] In view of the above, it can be seen that technical problems may arise when PRACH configuration according to NR technology is used for unlicensed carriers.

[0080] The present disclosure provides Figure 4a 、 4b , 5, 6, 7a to 7e, 8 and 9 illustrate exemplary embodiments of communication devices and methods that attempt to address the Figure 2a 、 2b The LBT failure in the RACH process in the unlicensed carrier shown in FIG3b increases the transmission opportunity of MSG1.

[0081] Figure 4a FIG. 4 is a schematic partial cross-sectional view of a base station 400 that can be used to establish a RACH process with a terminal according to the present disclosure. Figure 4b A schematic partial cross-sectional view of a terminal 450 according to the present disclosure is shown, which terminal 450 can be used with Figure 4a The base station shown establishes the RACH process.

[0082] According to the layered model, the various functions and operations of base station 400 and terminal 450 are arranged into layers. In this model, lower layers report to and receive instructions from higher layers according to the 3GPP 5G NR specifications. For simplicity, the details of the layered model are not discussed in this disclosure.

[0083] like Figure 4a As shown, the base station 400 is generally equipped with at least one radio transmitter 402, at least one radio receiver 404, at least one transmit signal generator 406, at least one receive signal processor 408, at least one antenna 412 and at least one controller 410 for software and hardware assisted execution of the tasks it is designed to perform, including controlling the Figure 4b The terminal 450 shown is accessed and communicated with. Data processing, storage, and other related control devices may be provided on appropriate circuit boards and / or chipsets. In various embodiments, at least one radio transmitter 402, at least one radio receiver 404, at least one transmit signal generator 406, at least one receive signal processor 408, and at least one antenna 412 may be controlled by at least one controller 410.

[0084] Similarly, if Figure 4b As shown, the terminal 450 is typically provided with at least one radio receiver 454, at least one radio transmitter 452, at least one transmit signal generator 456, at least one receive signal processor 458, at least one antenna 462, and at least one controller 460 for software and hardware assistance in performing the tasks it is designed to perform, including controlling the operation of devices such as Figure 4a4. The base station 400 is shown as a base station for accessing and communicating with the base station. Data processing, storage, and other related control devices can be provided on appropriate circuit boards and / or chipsets. In various embodiments, at least one radio transmitter 452, at least one radio receiver 454, at least one transmit signal generator 456, at least one receive signal processor 458, and at least one antenna 462 can be controlled by at least one controller 460.

[0085] At least one radio transmitter 402, at least one radio receiver 404, at least one transmit signal generator 406, at least one receive signal processor 408, and at least one controller 410 of the base station 400, and at least one radio transmitter 452, at least one radio receiver 454, at least one transmit signal generator 456, at least one receive signal processor 458, and at least one controller 460 of the terminal 450 provide functions required for establishing a RACH procedure between the terminal 450 and the base station 400 according to an embodiment of the present disclosure.

[0086] As mentioned above about Figure 1 As described above, before the 4-step RACH procedure, at least one radio transmitter 402 of the base station 400 transmits an SSB having an RMSI including PRACH configuration information to at least one radio receiver 454 of the terminal 450. Each SSB is associated with a plurality of ROs.

[0087] In the single RACH process, after receiving SSBs with RMSI from the base station, the controller 460 of the terminal 450 selects a good quality SSB among these SSBs and sends the PRACH preamble code as MSG1 on the RO associated with the selected / detected SSB to at least one radio receiver 404 of the base station 400.

[0088] In the multi-RACH process, after receiving an SSB with RMSI from the base station, the controller 460 of the terminal 450 selects a good quality SSB from multiple SSBs and sends different PRACH preamble codes as multiple MSG1s on multiple ROs associated with the selected / detected SSB to at least one radio receiver 404 of the base station 400.

[0089] The controller 460 of the terminal 450 may determine a plurality of ROs associated with the selected / detected SSB based on the PRACH configuration information included in the RMSI received from the base station 400. The plurality of ROs associated with the selected / detected SSB are considered as a plurality of RO candidates.

[0090] In the single RACH process, the terminal 450 performs an LBT process on each frequency region containing multiple RO candidates and selects an RO in the frequency region where the LBT succeeds from the multiple RO candidates to establish the single RACH process.

[0091] Similarly, in the multi-RACH process, the terminal 450 performs the LBT process on each frequency region containing multiple RO candidates, and selects multiple ROs in one or more frequency regions where LBT is successful among the multiple RO candidates to establish the multi-RACH process.

[0092] As described above, depending on the carrier bandwidth and the size of the LBT subband, the frequency range of the carrier may be divided into more than one frequency region. Therefore, multiple RO candidates may be distributed in more than one frequency region.

[0093] As described above, not all LBT procedures are successful. Therefore, an RO in a frequency region where LBT failed cannot be used for PRACH preamble transmission. However, an RO in another frequency region where LBT succeeded remains available among multiple RO candidates for terminal 450 to select for PRACH preamble transmission. As a result, the transmission opportunities of MSG1 during the RACH procedure increase.

[0094] In order to achieve a more efficient RACH process, the present disclosure provides a technical solution to maximize RO availability in the event of LBT failure in any frequency region. Figure 5 、 6 , 7a, 7b, 7c, 7d and 7e.

[0095] Figure 5 Examples of PRACH configurations for maximizing RO availability during a RACH procedure in an unlicensed carrier according to various embodiments of the present disclosure are shown.

[0096] As shown in the example, the frequency range of the carrier is divided into more than one frequency region. There are two frequency regions in the carrier: Figure 5 The first frequency region and the second frequency region are shown.

[0097] In this example, each of the more than one frequency regions is equal to an LBT sub-band. For example, if the LBT sub-band is 20 MHz, then Figure 5 Each of the illustrated first frequency region and second frequency region has a size of 20 MHz.

[0098] To maximize RO availability, PRACH is configured in each frequency region within a carrier, rather than per carrier. That is, each frequency region configured with PRACH contains ROs corresponding to all SSBs transmitted from base station 400. In this way, even if terminal 450 encounters a LBT failure in a frequency region, rendering the RO corresponding to the SSB selected / detected in that frequency region useless, terminal 450 can still find an RO corresponding to the same selected / detected SSB in another frequency region where LBT succeeded, for use in transmitting the PRACH preamble.

[0099] Furthermore, in this example, the selected / detected SSB may be transmitted from the base station 400 to the terminal 450 in only one of the one or more frequency regions. Alternatively, the selected / detected SSB may be transmitted from the base station 400 to the terminal 450 in more than one of the one or more frequency regions. To maximize RO availability, in either of these two scenarios, multiple RO candidates associated with the selected / detected SSB are distributed to multiple of the one or more frequency regions such that multiple of the one or more frequency regions contain ROs corresponding to the selected / detected SSB.

[0100] Advantageously, by means of Figure 5 (as well as Figure 6 、 7a , 7b, 7c, 7d and 7e) for maximizing RO availability, the transmission opportunities for MSG1 with LBT failure are increased, and the RACH process can be more efficient.

[0101] exist Figure 5 In the example shown, the PRACH configuration for each frequency region configured with PRACH may include parameters according to a higher layer protocol, such as prach-ConfigurationIndex, msg1-FrequencyStart, and msg1-FDM.

[0102] In some examples, one or more parameters in the PRACH configuration may be different in one or more frequency regions. That is, for each of the one or more frequency regions, one or more parameters in the PRACH configuration may have different values. For example, Figure 5 As shown, the parameter msg1-FrequencyStart specifying the starting position of the RO in the frequency domain may have different values, for example, msg1-FrequencyStart1 and msg1-FrequencyStart2, for different frequency regions, for example, the first frequency region and the second frequency region.

[0103] In some examples, one or more parameters in the PRACH configuration may be common across one or more frequency regions. That is, one or more parameters in the PRACH configuration may have the same value for each of the one or more frequency regions. For example, Figure 5 As shown, the parameter msg1-FDM indicating the number of ROs frequency-division multiplexed at one time may be the same in different frequency regions, such as the first frequency region and the second frequency region, for example, with a value of M of 2. In addition, the number of ROs time-division multiplexed within the PRACH time slot is included. The parameter indicating prach-ConfigurationIndex may be the same in different frequency regions, such as the first frequency region and the second frequency region, for example, having a value of 2. Advantageously, one or more parameters that are common in one or more frequency regions facilitate multiple RACH processes or a single RACH process over multiple frequency regions.

[0104] exist Figure 5 In the example shown, each frequency region (i.e., the first frequency region and the second frequency region) in the carrier is configured with a PRACH. However, it will be understood by those skilled in the art that in some alternative examples, a PRACH may not be configured in every frequency region of the carrier. In other words, a PRACH may be configured in some of all frequency regions.

[0105] In these alternative examples, parameters according to the higher layer protocol can be used to indicate and identify those frequency regions in which PRACH is configured among all frequency regions of the carrier. If only a single frequency region is configured with PRACH, it means that single RACH process or multiple RACH process is not allowed to be performed on multiple frequency regions.

[0106] Figure 6 Describes how Figure 5 In this embodiment of the PRACH configuration, association of SSBs with ROs (which may be interchangeably referred to as SSB-RO correspondence or SSB-RO mapping) is performed for each of one or more frequency regions configured with PRACH.

[0107] like Figure 6 As shown in FIG, in order to maximize RO availability, the value of SSB-perRACH-Occasion is set to be less than 1, for example, 1 / 4. In this way, each SSB is mapped to multiple ROs, for example. Figure 6 4 ROs shown.

[0108] exist Figure 6In an embodiment, for each of the one or more frequency regions configured with PRACH, the SSB to RO mapping is performed independently. In each of the one or more frequency regions, the ROs associated with the same SSB are at least time-division multiplexed in the PRACH time slot and / or distributed across the PRACH time slot.

[0109] By means of this SSB-RO correspondence, it is possible to perform a single RACH process or a multi-RACH process using multiple LBT processes in the time domain or frequency domain. In this way, even if the terminal 450 encounters an LBT failure in a frequency region, resulting in the RO corresponding to the selected / detected SSB in that frequency region being useless, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in another frequency region where LBT succeeded, for transmitting the PRACH preamble code.

[0110] For example, the terminal 450 may select multiple ROs associated with the detected SSBs for PRACH preamble transmission in a single RACH process or for multiple PRACH preamble transmissions in a multi-RACH process.

[0111] In the single RACH or multi-RACH process, the terminal 450 can select multiple ROs based on the following options:

[0112] Option 1: Select multiple ROs within the same frequency region to enable single RACH or multi-RACH processes with multiple LBT processes in the time domain.

[0113] Option 2: Select multiple ROs in different frequency regions and corresponding to the same time to enable a single RACH or multiple RACH processes with multiple LBT processes in the frequency domain.

[0114] Option 3: Select multiple ROs in different frequency regions and corresponding to different time instants to enable a single RACH or multiple RACH processes with multiple LBT processes in the time and frequency domains.

[0115] In the single RACH process, if LBT succeeds in one or more frequency regions containing more than one RO, the terminal 450 randomly selects one RO from the more than one RO and sends a PRACH preamble on the RO to the base station 400 to establish a single RACH process. In other words, in the single RACH process, a single PRACH preamble is sent.

[0116] In the multi-RACH process, when LBT succeeds in one or more frequency regions containing more than one RO, the terminal 450 will randomly select at least two ROs from the more than one ROs and send different PRACH preamble codes RO on the at least two ROs, corresponding to different RACH processes in the multi-RACH process.

[0117] Figure 7a 、 7b , 7c, 7d and 7e respectively show Figure 5 Each of these embodiments corresponds to SSB to RO correspondence / SSB to RO mapping / SSB to RO association performed on multiple frequency regions configured with PRACH.

[0118] Similar to Figure 6 , in order to maximize RO availability, Figure 7a 、 7b The value of SSB-perRACH-Occasion in the embodiments of 7c, 7d and 7e is set to be less than 1, for example, 1 / 4. In this way, each SSB is mapped to multiple ROs, for example, 4 ROs, as shown in FIG. Figure 7a 、 7b , 7c, 7d and 7e.

[0119] In the above embodiment, the parameter SSB-per-RACH-Occasion can be defined for each carrier. In this case, the number of ROs associated with SSB in each frequency region is the value of SSB-per-RACH-Occasion divided by the inverse of the number of frequency regions configured with PRACH in the carrier.

[0120] Alternatively, the parameter SSB-perRACH-Occasion can be defined per frequency region. In this scenario, the number of ROs associated with SSB per carrier is the value of SSB-perRACH-Occasion multiplied by the inverse of the number of frequency regions configured with PRACH in the carrier.

[0121] exist Figure 7a 、 7b In the examples shown in 7c, 7d, and 7e, the correspondence between SSBs and ROs is performed across multiple frequency regions configured with PRACH in a manner such that ROs associated with the same SSB are distributed across at least multiple frequency regions configured with PRACH and across time. To distribute ROs associated with the same SSB across time, ROs can be time-division multiplexed in each PRACH time slot. Additionally or alternatively, ROs can be distributed across PRACH time slots.

[0122] With the help of Figure 7a 、 7bThe correspondence between SSBs and ROs shown in the PRACH configuration embodiments of 7a, 7b, and 7e can utilize multiple LBT processes in the time domain or frequency domain to perform a single RACH process or a multi-RACH process. Advantageously, in this manner, even if the terminal 450 encounters an LBT failure in a frequency region that renders the RO corresponding to the selected / detected SSB in that frequency region useless, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in another frequency region that has successfully LBTed, for transmitting the PRACH preamble.

[0123] Figure 7a The correspondence between the first SSB and the RO performed on multiple frequency regions configured with PRACH is depicted. Figure 7a In the example shown, one SSB is associated with multiple ROs (e.g., 4 ROs), as described above. In this example, the SSB index can be mapped to the RO in the following order:

[0124] 1) In ascending order of frequency region index;

[0125] 2) in ascending order of the time resource index of the ROs time-division multiplexed within the PRACH time slot;

[0126] 3) in ascending order of frequency resource index of ROs used for frequency division multiplexing; and

[0127] 4) In ascending order of PRACH slot index.

[0128] In this example, the order of the frequency region index and the time resource index may be swapped.

[0129] By virtue of the correspondence between the first SSB and the RO, even if the terminal 450 encounters an LBT failure in a frequency region (e.g., the first frequency region), which renders the RO corresponding to the SSB selected / detected in the frequency region useless, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in which LBT succeeded in other frequency regions (e.g., the second frequency region) to send the PRACH preamble code.

[0130] Figure 7b The correspondence between the second SSB and the RO performed on multiple frequency regions configured with PRACH is depicted. Figure 7b In the example shown, one SSB is associated with multiple ROs (e.g., 4 ROs), as described above. In this example, the SSB index can be mapped to the RO in the following order:

[0131] 1) In ascending order of frequency region index;

[0132] 2) in ascending order of the time resource index of the ROs time-division multiplexed within the PRACH time slot;

[0133] 3) in ascending order of index used for PRACH slots; and

[0134] 4) In ascending order of frequency resource index of ROs used for frequency division multiplexing.

[0135] In this example, the order of the frequency region index and the time resource index may be swapped.

[0136] By virtue of the correspondence between the second SSB and the RO, even if the terminal 450 encounters an LBT failure in a frequency region (e.g., the first frequency region), which renders the RO corresponding to the SSB selected / detected in the frequency region useless, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in which LBT succeeded in other frequency regions (e.g., the second frequency region) for sending the PRACH preamble code.

[0137] Figure 7c The correspondence between the third SSB and the RO is depicted in FIG. Figure 7c In the example shown, one SSB is associated with multiple ROs (e.g., 4 ROs), as described above. In this example, the SSB index can be mapped to the RO in the following order:

[0138] 1) In ascending order of frequency region index;

[0139] 2) in ascending order of PRACH slot index;

[0140] 3) in ascending order of frequency resource index of ROs used for frequency division multiplexing; and

[0141] 4) In ascending order of the time resource index of the ROs multiplexed in time division.

[0142] In this example, the order of the frequency region index and the PRACH slot index may be swapped.

[0143] By virtue of the correspondence between the third SSB and the RO, even if the terminal 450 encounters an LBT failure in a frequency region (e.g., the first frequency region), which renders the RO corresponding to the SSB selected / detected in the frequency region useless, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in which LBT succeeded in other frequency regions (e.g., the second frequency region) to send the PRACH preamble code.

[0144] Furthermore, with the correspondence between the third SSB and the RO, even if the terminal 450 encounters an LBT failure in a PRACH slot, it may have a better chance of finding an RO in other PRACH slots that corresponds to the SSB mapped to the PRACH slot.

[0145] Figure 7d The fourth SSB and RO are described in FIG. Figure 7d In the example shown, one SSB is associated with multiple ROs (e.g., 4 ROs), as described above. In this example, the SSB index can be mapped to the RO in the following order:

[0146] 1) Arrange in ascending order of frequency region index;

[0147] 2) in ascending order of PRACH slot index;

[0148] 3) in ascending order of the time rate resource index of the RO used for time division multiplexing; and

[0149] 4) In ascending order of the frequency resource index of the ROs multiplexed in frequency division.

[0150] In this example, the order of the frequency region index and the PRACH slot index may be swapped.

[0151] By virtue of the correspondence between the fourth SSB and the RO, even if the terminal 450 encounters an LBT failure in a frequency region (e.g., the first frequency region), which renders the RO corresponding to the SSB selected / detected in the frequency region useless, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in which LBT succeeded in other frequency regions (e.g., the second frequency region) for sending the PRACH preamble code.

[0152] In addition, with the help of the correspondence between the fourth SSB and the RO, even if the terminal 450 encounters an LBT failure in a PRACH time slot, it may have a better chance to find the RO corresponding to the SSB mapped to the PRACH time slot in other PRACH time slots.

[0153] Figure 7e The fifth SSB and RO are described in FIG. Figure 7e In the example shown, one SSB is associated with multiple ROs (eg, 4 ROs), as described above, and in Figures 7a to 7d The first to fourth SSBs shown are at the corresponding tops of the ROs, and an interleaving operation is applied to the PRACH slot index.

[0154] By virtue of the correspondence between the fifth SSB and the RO, even if the terminal 450 encounters an LBT failure in a frequency region (e.g., the first frequency region), which causes the RO corresponding to the SSB selected / detected in the frequency region to be invalid, the terminal 450 can still find an RO corresponding to the same selected / detected SSB in which LBT succeeded in other frequency regions (e.g., the second frequency region) for sending the PRACH preamble code.

[0155] In addition, with the help of the correspondence between the fifth SSB and the RO, even if the terminal 450 encounters LBT failure in two or more consecutive PRACH time slots, the terminal 450 may have a better chance of finding the RO in other PRACH time slots corresponding to the SSB mapped to the two or more consecutive PRACH time slots.

[0156] The correspondence of the third, fourth, or fifth SSBs with the RO is advantageous in situations where an NR standalone system operating in an unlicensed band (e.g., 5 GHz or 6 GHz unlicensed band) coexists with a Wi-Fi network where the physical layer protocol data unit (PPDU) duration may be longer than one or more PRACH slots.

[0157] In view of the above five SSB to RO correspondences, according to various embodiments of the present disclosure, more than one of the five SSB to RO correspondences may be used in the process of establishing a single RACH or multi-RACH procedure between the base station 400 and the terminal 450 .

[0158] according to Figure 5 、 6 , 7a, 7b, 7c, 7d and 7e described in the above single RACH process and multiple RACH process examples of the PRACH configuration can be referred to Figure 4a and 4b describe.

[0159] In some embodiments, at least one transmit signal generator 456 of terminal 450 generates a first PRACH preamble. At least one radio transmitter 452 of terminal 450 transmits the first PRACH preamble to base station 400 on a first RO among multiple RO candidates. The multiple RO candidates may be determined by at least one controller 460 of terminal 450 based on PRACH configuration information received from base station 400. The first RO is allocated within a first frequency region equal to the first subband in which the LBT process is performed at terminal 450. In other words, the size of the first frequency region is equal to the size of the first LBT subband. For example, if the first LBT subband is 20 MHz, the first frequency region has a size of 20 MHz.

[0160] As described above, in a single RACH process, terminal 450 can select multiple ROs from multiple RO candidates for PRACH preamble transmission. Similarly, in a multi-RACH process, terminal 450 can select multiple ROs from multiple RO candidates for multiple PRACH preamble transmission. The multiple RO candidates are associated with the SSBs selected / detected by terminal 450 from the SSBs received from base station 400.

[0161] Therefore, in some examples, the terminal 450 needs to select multiple ROs from multiple RO candidates for a single RACH process or multiple RACH processes.

[0162] In these examples, at least one transmit signal generator 456 of terminal 450 can further generate a second PRACH preamble. In these embodiments, at least one radio transmitter 452 of terminal 450 transmits the second PRACH preamble to the base station on a second RO from among the multiple RO candidates. The second RO is allocated within a second frequency region equal to the second sub-frequency band in which the LBT process is performed at terminal 450. In other words, the second frequency region has a size equal to the second LBT sub-band. For example, if the second LBT sub-band is 20 MHz, the second frequency region has a size of 20 MHz.

[0163] It is obvious to those skilled in the art that, based on actual needs and network configuration, the at least one transmit signal generator 456 of the terminal 450 may further generate more PRACH preamble codes for transmission on more ROs by the at least one radio transmitter 452 of the terminal 450. More ROs may be allocated in other frequency regions or in the first and / or second frequency regions.

[0164] As described above, in the single RACH process, when LBT succeeds in one or more frequency regions including more than one RO, the at least one controller 460 of the terminal 450 may randomly select one RO from the more than one RO, and transmit a PRACH preamble code on the RO to the base station 400. In other words, in the single RACH process, a single PRACH preamble code is transmitted.

[0165] Similarly, in a multi-RACH process, if LBT succeeds in one or more frequency regions including more than one RO, at least one controller 460 of the terminal 450 may randomly select at least two ROs from the more than one RO and transmit different PRACH preambles to the base station 400 on the at least two ROs in different RACH processes in the multi-RACH process. The terminal 450 may generate the first PRACH preamble and the second PRACH preamble based on the same sequence or different sequences. When the same sequence is used to generate the first PRACH preamble and the second PRACH preamble, different cyclic shifts are applied to the same sequence.

[0166] In some embodiments, the PRACH configuration information received by at least one radio receiver 454 of the terminal 450 from the base station 400 may include a parameter identifying the frequency regions configured for the PRACH. In some examples, the parameter identifies the first frequency region and the second frequency region configured for the PRACH. However, not every frequency region in the carrier may be configured with the PRACH. Therefore, in some alternative examples, the parameter may identify some frequency regions among all frequency regions in the carrier as being configured with the PRACH. For example, the parameter may be a bitmap whose size is the number of frequency regions in the carrier. Each bit of the bitmap indicates whether the corresponding frequency region is configured with the PRACH.

[0167] In some embodiments, the PRACH configuration information received by the at least one radio receiver 454 of the terminal 450 from the base station 400 may include one or more parameters common to the first frequency region and the second frequency region. That is, for each of the first frequency region and the second frequency region, the one or more parameters in the PRACH configuration may have the same value. For example, the one or more parameters indicate the number of ROs frequency-division multiplexed at one time in the first frequency region and the second frequency region, such as Figure 5 described.

[0168] In some embodiments, the PRACH configuration information received by the at least one radio receiver 454 of the terminal 450 from the base station 400 may include one or more parameters in the PRACH configuration that are different in the first frequency region and the second frequency region. That is, for each of the first frequency region and the second frequency region, the one or more parameters in the PRACH configuration may have different values. For example, the one or more parameters indicate the starting position of the RO in the frequency domain in the first frequency region or the second frequency region, such as Figure 5 described.

[0169] As described above, a plurality of RO candidates are associated with an SSB selected / detected by the terminal 450 from the SSBs received by the base station 400. In some embodiments, the selected / detected SSB may be transmitted from the base station 400 to the terminal 450 in one of the first frequency region and the second frequency region. Alternatively, the selected / detected SSB may be transmitted from the base station 400 to the terminal 450 in both the first frequency region and the second frequency region. To maximize RO availability, in either of these two scenarios, the plurality of RO candidates associated with the selected / detected SSB are distributed to each of the first frequency region and the second frequency region, such that each of the first frequency region and the second frequency region contains an RO corresponding to the selected / detected SSB.

[0170] In some examples, such as Figure 6 As described, a plurality of RO candidates are determined based on the correspondence between the SSB and the RO for the first frequency region or the second frequency region.

[0171] In some examples, such as Figure 7a 、 7b As described in , 7c, 7d and 7e, multiple RO candidates are determined based on the correspondence between SSBs and ROs for the first frequency region and the second frequency region. In these examples, multiple RO candidates associated with SSBs are distributed across the first frequency region and the second frequency region, and across time.

[0172] Figure 8 Shown according to Figures 5 to 7e The various embodiments shown may be implemented as another illustrative example of a base station establishing a RACH procedure in an unlicensed carrier.

[0173] exist Figure 8 In an illustrative example, at least one controller 830 of a base station may include at least a PRACH configuration determiner 832, a scheduler 834, a message parser 836, and an LBT circuit 838. The PRACH configuration determiner 832 is configured to determine the PRACH configuration in the carrier. The scheduler 834 is configured to schedule the transmission of high-layer messages (e.g., MSG2, MSG4) and system information (such as RMSI, etc.) to the terminal. The scheduler 834 is also configured to generate an uplink grant for the transmission of a high-layer message (e.g., MSG3) for the terminal. The message parser 836 is configured to analyze the PRACH preamble and high-layer message (e.g., MSG3) received from the terminal. The LBT circuit 838 is configured to perform an LBT process, for example, at each frequency region / subband in the carrier.

[0174] exist Figure 8In the illustrative example of , at least one transmit signal generator 810 may include at least a system information generator 812 , a message generator 814 , an encoder and a modulator 816 . At least one receive signal processor 820 may include at least a demodulator and a decoder or detector 822 .

[0175] The system information generator 812 is configured to generate system information, such as RMSI, based on the results from the PRACH configuration determiner 832 and the scheduler 834 .

[0176] Based on the LBT result provided by the LBT circuit 838, the message generator 814 is configured to generate a higher layer message, such as a random access response message (MSG2) in response to the reception of the PRACH preamble code from the terminal or a contention resolution message (MSG4) in response to the reception of the scheduled transmission message (MSG3) from the terminal.

[0177] The encoder and modulator 816 is configured to encode and modulate the generated system information received from the system information generator 812 or the higher layer message received from the message generator 814 .

[0178] The demodulator and decoder or detector 822 is configured to detect the PRACH preamble (MSG1) received from the terminal, or demodulate and decode the higher layer message (eg, MSG3) received from the terminal, or sense the LBT subband in the carrier.

[0179] Figure 9 Shown according to Figures 5 to 7e The various embodiments shown are another illustrative example of a terminal that can be implemented to establish a RACH procedure in an unlicensed carrier.

[0180] exist Figure 9 In an illustrative example, at least one controller 930 of a terminal may include at least a PRACH configuration determiner 932, a beam determiner 934, an RO determiner 936, a message parser 938, and an LBT circuit 940. The PRACH configuration determiner 932 is configured to determine PRACH configuration information based on system information received from a base station. The beam determiner 934 is configured to determine the best beam / SSB or a beam / SSB of sufficiently good quality from the SSBs transmitted by the base station. Based on the LBT results provided by the LBT circuit 940, the RO determiner 936 is configured to determine / select one or more ROs from multiple RO candidates corresponding to the SSBs selected by the beam determiner 934. The message parser 938 is configured to analyze higher layer messages (e.g., MSG2, MSG4) received from the base station. The LBT circuit 940 is configured to perform an LBT process, for example, on each frequency region / subband in a carrier where PRACH is configured.

[0181] exist Figure 9 In the illustrative example of , the transmit signal generator 910 may include at least a PRACH transmit signal generator 912 , a message generator 914 , an encoder and modulator 916 , and the receive signal processor 920 may include at least a demodulator and decoder 922 .

[0182] The demodulator and decoder 922 is configured to demodulate and decode a received signal (e.g., system information or a higher layer message) received from a base station, or to sense an LBT subband in a carrier via at least one radio receiver 904 of the terminal. The decoded system information or higher layer message is provided to the PRACH configuration determiner 932, the beam determiner 934, the RO determiner 936, and the message parser 938 to perform their respective functions.

[0183] The PRACH transmit signal generator 912 is configured to generate a PRACH preamble signal at one or more ROs determined / selected by the RO determiner 936 in the controller 930 .

[0184] The message generator 914 is configured to generate a high-level message (eg, MSG3).

[0185] The encoder and modulator 916 is configured to encode and modulate the generated higher layer message (eg, MSG3) received from the message generator 914 for transmission by the at least one radio transmitter 902 of the terminal to the base station.

[0186] As described above, embodiments of the present disclosure provide an advanced communication system, communication method, and communication device that can implement a more efficient RACH procedure and have an increase in MSG1 transmission opportunities for LBT failures in unlicensed carriers.

[0187] The present disclosure can be implemented by software, hardware, or software in collaboration with hardware. Each functional block used in the description of each of the above embodiments can be partially or fully implemented by an LSI such as an integrated circuit, and each process described in each embodiment can be partially or fully controlled by the same LSI or a combination of LSIs. The LSI can be formed as a chip alone, or a chip can be formed to include some or all functional blocks. The LSI may include data inputs and outputs coupled thereto. Depending on the difference in integration, the LSI here may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI. However, the technology for implementing an integrated circuit is not limited to LSI, and can be implemented by using a dedicated circuit, a general-purpose processor, or a dedicated processor. In addition, an FPGA (field programmable gate array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connections and settings of the circuit units arranged inside the LSI can be used. The present disclosure can be implemented as digital processing or analog processing. If future integrated circuit technology replaces LSI due to advances in semiconductor technology or other derivative technologies, future integrated circuit technology can be used to integrate the functional blocks. Biotechnology can also be applied.

[0188] The present disclosure may be implemented by any kind of apparatus, device, or system having a communication function, which is referred to as a communication device.

[0189] Some non-limiting examples of such communication devices include phones (e.g., cellular (cellular) phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still cameras / camcorders), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, digital book readers, telehealth / telemedicine (telehealth and medicine) devices, and vehicles that provide communication capabilities (e.g., cars, airplanes, ships), and various combinations thereof.

[0190] Communication devices are not limited to portable or movable devices, but can also include any type of non-portable or fixed device, apparatus or system, such as smart home devices (e.g., home appliances, lighting devices, smart meters, control panels), vending machines, and any other "things" in the "Internet of Things (IoT)" network.

[0191] Communications may include exchanging data via, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0192] A communication device may include a device, such as a controller or a sensor, coupled to the communication device that performs the communication functions described in the present disclosure. For example, a communication device may include a controller or a sensor that generates a control signal or a data signal that is used by a communication device that performs the communication functions of the communication device.

[0193] Communications equipment may also include infrastructure such as base stations, access points, and any other device, apparatus, or system that communicates with or controls devices such as the non-limiting examples above.

[0194] Those skilled in the art will appreciate that various changes and / or modifications may be made to the present disclosure as shown in the specific embodiments without departing from the spirit or scope of the present disclosure as broadly described. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive.

[0195] According to the present disclosure, various features are provided, such as:

[0196] 1. A terminal, comprising:

[0197] circuitry for generating a first random access preamble; and

[0198] a transmitter that sends a first random access preamble to a base station on a first physical random access channel (PRACH) opportunity (RO) among a plurality of RO candidates, the plurality of RO candidates being determined based on PRACH configuration information received from the base station,

[0199] The first RO is allocated in a first frequency region, which is equal to a first subband in which a listen-before-talk (LBT) process is performed at the terminal.

[0200] 2. A terminal according to statement 1, wherein

[0201] The circuit generates a second random access preamble; and

[0202] The transmitter sends the second random access preamble to the base station on a second RO among the multiple RO candidates,

[0203] The second RO is allocated in a second frequency region, and the second frequency region is equal to a second subband in which the LBT process is performed at the terminal.

[0204] 3. A terminal according to statement 2, wherein the first random access preamble and the second random access preamble are generated from the same sequence.

[0205] 4. The terminal of statement 2, wherein the first frequency region is the same as the second frequency region.

[0206] 5. A terminal according to statement 2, wherein the first frequency region is different from the second frequency region.

[0207] 6. A terminal according to statement 2, comprising: a receiver that receives a parameter included in the PRACH configuration information, the parameter identifying the first frequency region and the second frequency region for the PRACH configuration.

[0208] 7. A terminal according to statement 2, comprising a receiver that receives one or more parameters included in the PRACH configuration information, the one or more parameters being common in the first frequency region and the second frequency region.

[0209] 8. The terminal of statement 7, wherein the one or more parameters indicate the number of ROs that are frequency-domain multiplexed in the first frequency region and the second frequency region at one time instant.

[0210] 9. A terminal according to statement 2, comprising a receiver that receives one or more parameters included in the PRACH configuration information, the one or more parameters being different between the first frequency region and the second frequency region.

[0211] 10. The terminal of statement 9, wherein the one or more parameters indicate a starting position of the RO in the frequency domain in the first frequency region or the second frequency region.

[0212] 11. The terminal of statement 1, wherein the plurality of RO candidates are associated with synchronization signal blocks (SSBs) received from the base station.

[0213] 12. The terminal of statement 11, wherein the plurality of RO candidates are determined based on correspondence between SSBs of the first frequency region or the second frequency region and ROs.

[0214] 13. The terminal of statement 11, wherein the plurality of RO candidates are determined based on correspondence between SSBs and ROs in the first frequency region and the second frequency region, wherein the plurality of RO candidates associated with the SSBs are:

[0215] distributed across a first frequency region and a second frequency region, and

[0216] Distribution across time.

[0217] 14. The terminal of statement 2, wherein the plurality of RO candidates are associated with SSBs transmitted in the first frequency region or the second frequency region.

[0218] 15. A base station, comprising:

[0219] circuitry for determining a PRACH configuration, the PRACH configuration comprising a plurality of RO candidates; and

[0220] a receiver, receiving a first random access preamble from a terminal on a first RO among a plurality of RO candidates,

[0221] The first RO is allocated in a first frequency region, which is equal to a first subband where the LBT process is performed at the terminal.

[0222] 16. A base station according to statement 15, wherein

[0223] The receiver receives a second random access preamble from the terminal on a second RO among the plurality of RO candidates, wherein the second RO is allocated within a second frequency region, the second frequency region being equal to a second subband in which the LBT process is performed at the terminal.

[0224] 17. A base station as described in statement 16, wherein the first random access preamble and the second random access preamble are generated from the same sequence.

[0225] 18. A base station as described in statement 16, wherein the first frequency region is the same as the second frequency region.

[0226] 19. A base station as described in statement 16 wherein the first frequency region is different from the second frequency region.

[0227] 20. A base station as recited in statement 16, wherein the transmitter transmits parameters included in the PRACH configuration information, the parameters identifying the first frequency region and the second frequency region for the PRACH configuration.

[0228] 21. A base station as recited in statement 16, wherein the transmitter transmits one or more parameters in the PRACH configuration information, the one or more parameters being common in the first frequency region and the second frequency region.

[0229] 22. The base station of statement 21, wherein the one or more parameters indicate a number of ROs that are frequency domain multiplexed in the first frequency region and the second frequency region at one time instant.

[0230] 23. A base station as recited in statement 16, wherein the transmitter transmits one or more parameters in PRACH configuration information, the one or more parameters being different between the first frequency region and the second frequency region.

[0231] 24. A base station according to statement 23, wherein the one or more parameters indicate a starting position of the RO in the frequency domain in the first frequency region or the second frequency region.

[0232] 25. The base station of statement 15, wherein the plurality of RO candidates are associated with an SSB sent to the terminal.

[0233] 26. The base station of statement 25, comprising: a controller that arranges the plurality of RO candidates based on correspondence of SSBs and ROs for the first frequency region or the second frequency region.

[0234] 27. A base station according to statement 25, comprising a controller that arranges the plurality of RO candidates based on correspondence of SSBs and ROs for the first frequency region and the second frequency region, wherein the plurality of RO candidates associated with an SSB:

[0235] distributed across a first frequency region and a second frequency region, and

[0236] Distribution across time.

[0237] 28. The base station of statement 11, wherein the plurality of RO candidates are associated with SSBs transmitted in the first frequency region or the second frequency region.

[0238] 29. A communication method comprising:

[0239] generating a first random access preamble at the terminal; and

[0240] sending the first random access preamble from the terminal to the base station on a first RO among a plurality of RO candidates, the plurality of RO candidates being determined based on PRACH configuration information received from the base station,

[0241] The first RO is allocated in a first frequency region, which is equal to a first subband where the LBT process is performed at the terminal.

[0242] 30. A communication method, comprising:

[0243] determining, at a base station, a PRACH configuration, the PRACH configuration including a plurality of RO candidates; and

[0244] receiving a first random access preamble at the base station on a first RO among the plurality of RO candidates,

[0245] The first RO is allocated in a first frequency region, which is equal to a subband in which an LBT process is performed at the terminal.

Claims

1. A communication device comprising: a receiver, receiving a first synchronization signal block SSB from a base station, and receiving physical random access channel PRACH configuration information from the base station; and a transmitter coupled to the receiver and transmitting a first random access preamble to the base station on a first RO or a second RO among a plurality of physical random access channel (PRACH) opportunity RO candidates corresponding to the SSB index of the received first SSB, According to the allocation mode based on the PRACH configuration information, the multiple RO candidates corresponding to the SSB index are allocated in multiple frequency regions, wherein, at the same time, a first RO among the multiple RO candidates is allocated in a first frequency region, and a second RO among the multiple RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each frequency region of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal. The PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and The positions of the RO candidates on the first frequency region and the second frequency region are determined at least based on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

2. The communication device according to claim 1, wherein Each of the plurality of frequency regions is 20 MHz.

3. The communication device according to claim 1, wherein One or more parameters included in the PRACH configuration information are common among the multiple frequency regions. The communication device according to claim 1 , wherein: The plurality of RO candidates are determined based on PRACH configuration information received from the base station. The communication device according to claim 1 , wherein: A second random access preamble is sent to the base station on a second RO among another plurality of RO candidates corresponding to another SSB index.

6. The communication device according to claim 1, wherein an SSB index including the SSB index is associated with the plurality of ROs in the order of a frequency resource index, a time resource index, and a PRACH slot index.

7. A communication method performed by a communication device, comprising: receiving a first synchronization signal block SSB from a base station, and receiving physical random access channel PRACH configuration information from the base station; and Sending a first random access preamble to the base station on a first RO or a second RO among a plurality of physical random access channel (PRACH) opportunity RO candidates corresponding to the SSB index of the received first SSB, According to the allocation mode based on the PRACH configuration information, the multiple RO candidates corresponding to the SSB index are allocated in multiple frequency regions, wherein, at the same time, a first RO among the multiple RO candidates is allocated in a first frequency region, and a second RO among the multiple RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each frequency region of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal. The PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and The positions of the RO candidates on the first frequency region and the second frequency region are determined at least based on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

8. A base station, comprising: A transmitter sends a first synchronization signal block SSB and physical random access channel PRACH configuration information; and a receiver that receives a first random access preamble from a communication device on a first RO or a second RO among a plurality of PRACH opportunity RO candidates corresponding to the SSB index of the first SSB, According to the allocation mode based on the PRACH configuration information, the multiple RO candidates corresponding to the SSB index are allocated in multiple frequency regions, wherein, at the same time, a first RO among the multiple RO candidates is allocated in a first frequency region, and a second RO among the multiple RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each frequency region of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal. The PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and The positions of the RO candidates on the first frequency region and the second frequency region are determined at least based on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

9. The base station according to claim 8, wherein: in, Each of the plurality of frequency regions is 20 MHz.

10. The base station according to claim 8, wherein: One or more parameters included in the PRACH configuration information are common among the multiple frequency regions.

11. The base station according to claim 8, wherein: The plurality of RO candidates are determined based on PRACH configuration information received from the base station.

12. The base station according to claim 8, wherein The second random access preamble is transmitted to the base station on a second RO among another plurality of RO candidates corresponding to another SSB index.

13. The base station according to claim 8, wherein the SSB index including the SSB index is associated with the multiple ROs in the order of frequency resource index, time resource index and PRACH time slot index.

14. A communication method performed by a base station, comprising: Send the first synchronization signal block SSB and physical random access channel PRACH configuration information; and receiving a first random access preamble from a communication device on a first RO or a second RO of a plurality of physical random access channel (PRACH) opportunity RO candidates corresponding to the SSB index of the first SSB, According to the allocation mode based on the PRACH configuration information, the multiple RO candidates corresponding to the SSB index are allocated in multiple frequency regions, wherein, at the same time, a first RO among the multiple RO candidates is allocated in a first frequency region, and a second RO among the multiple RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each frequency region of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal. The PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and The positions of the RO candidates on the first frequency region and the second frequency region are determined at least based on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

15. An integrated circuit comprising: Circuit, control: receiving a first synchronization signal block SSB from a base station, and receiving physical random access channel PRACH configuration information from the base station; and Sending a first random access preamble to the base station on a first RO or a second RO among a plurality of physical random access channel (PRACH) opportunity RO candidates corresponding to the SSB index of the received first SSB, According to the allocation mode based on the PRACH configuration information, the multiple RO candidates corresponding to the SSB index are allocated in multiple frequency regions, wherein, at the same time, a first RO among the multiple RO candidates is allocated in a first frequency region, and a second RO among the multiple RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each frequency region of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal. The PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and The positions of the RO candidates on the first frequency region and the second frequency region are determined at least based on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

16. An integrated circuit comprising: Circuit, control: Send the first synchronization signal block SSB and physical random access channel PRACH configuration information; and receiving a first random access preamble from a communication device on a first RO or a second RO of a plurality of physical random access channel (PRACH) opportunity RO candidates corresponding to the SSB index of the first SSB, According to the allocation mode based on the PRACH configuration information, the multiple RO candidates corresponding to the SSB index are allocated in multiple frequency regions, wherein, at the same time, a first RO among the multiple RO candidates is allocated in a first frequency region, and a second RO among the multiple RO candidates is allocated in a second frequency region, and the second frequency region is different from the first frequency region along the frequency axis, wherein each frequency region of the multiple frequency regions is equal to a subband in which a listen-before-talk (LBT) process is performed at a terminal. The PRACH configuration information is configured according to each of the multiple frequency regions and includes a prach-ConfigurationIndex, wherein the prach-ConfigurationIndex indicates a PRACH time resource for a first RO and a second RO corresponding to the SSB index, and The positions of the RO candidates on the first frequency region and the second frequency region are determined at least based on the msg1-FDM common to the first frequency region and the second frequency region and included in the PRACH configuration information, and the msg1-FDM indicates the number of frequency-division multiplexed ROs in each of the first frequency region and the second frequency region at a time.

Images