Network device, terminal device and method therein

Abstract

The present disclosure provides a method (700) in a network device. The method (700) includes: sending (710) a random access channel (RACH) timing configuration to a terminal device, and receiving (720) a RACH preamble sent from the terminal device according to the RACH timing configuration. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send the RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the second random access procedure.

Description

Technical Field

[0001] The present disclosure relates to wireless communications, and more particularly, to network devices, terminal devices, and methods therein. Background Art

[0002] In New Radio (NR) and Long Term Evolution (LTE) networks for accessing new cells, random access is performed by a terminal device, such as a user equipment (UE). Once the random access procedure is completed, the terminal device is able to connect to a network device, such as an evolved NodeB (eNB) or gNB, and communicate with the network device using dedicated transport.

[0003] A four-step random access procedure has been defined for NR. Figure 1A The signaling sequence of the four-step random access procedure is shown. As shown, at 101, the UE detects the synchronization signal (SS) from the gNB. At 102, the UE decodes the master information block (MIB) and system information block (SIB) (i.e., remaining minimum system information (RMSI) and other system information (OSI)), which may be distributed over multiple physical channels, such as the physical broadcast channel (PBCH) and the physical downlink shared channel (PDSCH), to obtain random access transmission parameters. At 111, the UE sends a physical random access channel (PRACH) preamble or message 1 to the gNB. At 112, the gNB detects message 1 and responds with a random access response (RAR) or message 2. At 113, based on the configuration information for PUSCH transmission carried in the RAR, the UE sends a physical uplink shared channel (PUSCH) or message 3 to the gNB. At 114, the gNB sends a contention resolution message or message 4 to the UE.

[0004] In such Figure 1A In the four-step random access process shown, the resources used for PUSCH (i.e., message 3) are indicated in the RAR (i.e., message 2), which include time resources and frequency resources. In particular, the RAR contains an uplink grant, which includes a 14-bit "PUSCH frequency resource allocation" field indicating the frequency domain resources used for PUSCH, and a 4-bit "PUSCH time resource allocation" field indicating the time domain resources used for PUSCH.

[0005] In order to minimize the number of channel accesses (which is important, for example, for operation in unlicensed bands, where listen before talk (LBT) is required before transmission), a two-step random access procedure for NR is also proposed. Instead of using four steps 111-114, the two-step random access procedure uses two messages to complete random access in only two steps, which can be referred to as message A and message B. Figure 1BThe signaling sequence of the two-step random access process is shown in FIG. Figure 1B Steps 101 to 102 in Figure 1A 101-102 are the same as in 101-102. At 121, the UE sends the PRACH preamble and PUSCH to the gNB in ​​one message (i.e., message A, msgA). The PUSCH may include higher layer data, such as a radio resource control (RRC) connection request, and may have some small additional payload. At 122, the gNB sends message B (msgB) to the UE, including UE identifier allocation, timing advance information, and CRM, etc. Summary of the invention

[0006] The purpose of the present disclosure is to provide a network device, a terminal device and a method therein, which can determine the time-frequency resources of the RACH opportunities used for two-step and four-step random access processes.

[0007] According to the first aspect of the present disclosure, a method in a network device is provided. The method may include: sending a random access channel (RACH) timing configuration to a terminal device, and receiving a RACH preamble sent from the terminal device according to the RACH timing configuration. The RACH timing configuration may include: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the second random access procedure.

[0008] In an embodiment, the second set of time resources is at least partially different from the first set of time resources in the time domain, and / or the second set of frequency resources is at least partially different from the first set of frequency resources in the frequency domain.

[0009] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion in a RACH configuration table and the first time resource indication identifies a different portion in the RACH configuration table.

[0010] In an embodiment, the portion may include rows and / or columns in the RACH configuration table.

[0011] In an embodiment, an existing RACH configuration table configured for the first random access procedure is reused or modified as the RACH configuration table.

[0012] In an embodiment, the first time resource indication is in the form of a first RACH configuration table, and the second time resource indication is in the form of a second RACH configuration table different from the first RACH configuration table.

[0013] In an embodiment, the second frequency resource indication may include: a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource, and / or a parameter defining an offset of a lowest RACH opportunity relative to an index of a physical resource block (PRB).

[0014] In an embodiment, the PRB is the first PRB in a bandwidth portion containing the second set of frequency resources, or is a PRB in the first set of frequency resources.

[0015] In an embodiment, the PRB in the first frequency resource set is a PRB whose index is the minimum or maximum index in the first frequency resource set.

[0016] In an embodiment, a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities frequency-division multiplexed in the at least one time resource used for the first random access procedure, a preamble format used for the second random access procedure, a frequency band used for the second random access procedure, and a RACH time configuration for the second random access procedure.

[0017] In an embodiment, the method may further include determining whether the received RACH preamble is associated with the first random access procedure or the second random access procedure.

[0018] In an embodiment, the method may further comprise: in response to determining that the received RACH preamble is associated with the first random access procedure, sending a random access response (RAR) to the terminal device.

[0019] In an embodiment, the method may further comprise: in response to receiving a RACH preamble without receiving PUSCH data, sending a random access response (RAR) to the terminal device, wherein the RACH preamble is associated with the second random access procedure.

[0020] In an embodiment, the second time resource indication and the second frequency resource indication are configured by considering at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; a possible conflict between the second random access procedure and the first random access procedure; and a possible conflict between the second random access procedure and other signals other than the RACH preamble code.

[0021] In an embodiment, the second time resource indication and the second frequency resource indication may indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

[0022] In an embodiment, the second time resource indication and the second frequency resource indication may further indicate an associated period.

[0023] In an embodiment, the association period is configured by considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration.

[0024] In an embodiment, the second time resource indication and the second frequency resource indication are sent via an RRC message.

[0025] In an embodiment, a subset of time resources or frequency resources is configured by considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire set of synchronization signal (SS) / physical broadcast channel (PBCH) blocks (SSBs) in one SSB burst set; the number of SSBs actually sent; the RACH configuration index; and whether the spectrum type is paired spectrum or unpaired spectrum.

[0026] In an embodiment, the time resource is a subframe if the RACH preamble is transmitted in a first frequency range, or a time slot if the RACH preamble is transmitted in a second frequency range.

[0027] In an embodiment, the first random access procedure is a four-step random access procedure, and the second random access procedure is a two-step random access procedure. In the two-step random access procedure, the terminal device sends a message A including a RACH preamble and PUSCH data.

[0028] According to a second aspect of the present disclosure, a network device is provided. The terminal device may include a transceiver, a processor and a memory. The memory contains instructions executable by the processor, whereby the network device is operable to implement the method according to the first aspect above.

[0029] According to a third aspect of the present disclosure, a computer-readable storage medium is provided. Computer program instructions are stored on the computer-readable storage medium. When the computer program instructions are executed by a processor in a network device, the computer program instructions enable the network device to implement the method according to the first aspect above.

[0030] According to a fourth aspect of the present disclosure, a method in a terminal device is provided. The method may include: receiving a random access channel (RACH) timing configuration from a network device, and sending a RACH preamble according to the RACH timing configuration. The RACH timing configuration may include: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the second random access procedure.

[0031] In an embodiment, the second set of time resources is at least partially different from the first set of time resources in the time domain, and / or the second set of frequency resources is at least partially different from the first set of frequency resources in the frequency domain.

[0032] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion in a RACH configuration table and the first time resource indication identifies a different portion in the RACH configuration table.

[0033] In an embodiment, the portion may include rows and / or columns in the RACH configuration table.

[0034] In an embodiment, an existing RACH configuration table configured for the first random access procedure is reused or modified as the RACH configuration table.

[0035] In an embodiment, sending the RACH preamble according to the RACH opportunity configuration may include determining a lowest RACH opportunity in the second frequency resource set by adding one or more to an index of a PRB whose index is a maximum index in the first frequency resource set.

[0036] In an embodiment, the second frequency resource indication may include: a parameter defining an offset of a lowest RACH opportunity relative to a PRB, and sending a RACH preamble according to the RACH opportunity configuration may include: determining a lowest RACH opportunity in the second frequency resource set by at least one of:

[0037] adding the offset to an index of a first PRB in a bandwidth part containing the second set of frequency resources,

[0038] in case the PRB is the first PRB in the bandwidth part containing the second frequency resource set, adding the offset to the index of the PRB whose index is the smallest index in the first frequency resource set, and

[0039] The offset is added to the index of the PRB whose index is the largest index in the first frequency resource set.

[0040] In an embodiment, the second frequency resource indication comprises: a parameter defining the number of RACH opportunities frequency division multiplexed in at least one time resource.

[0041] In an embodiment, a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities frequency-division multiplexed in at least one time resource for the first random access procedure, a preamble format for the second random access procedure, a frequency band for the second random access procedure, and a RACH time configuration for the second random access procedure.

[0042] In an embodiment, the second time resource indication and the second frequency resource indication indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

[0043] In an embodiment, the method may further include: in response to determining that the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble code according to the second random access procedure are within the first time resource set and the first frequency resource set, sending the RACH preamble code in the time-frequency resources according to the first random access procedure.

[0044] In an embodiment, the second time resource indication and the second frequency resource indication further indicate an associated period.

[0045] In an embodiment, the association period is configured by considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration.

[0046] In an embodiment, the second time resource indication and the second frequency resource indication are received via an RRC message.

[0047] In an embodiment, a subset of time resources or frequency resources is configured by considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire set of synchronization signal (SS) / physical broadcast channel (PBCH) blocks (SSBs) in one SSB burst set; the number of SSBs actually sent; the RACH configuration index; and whether the spectrum type is paired spectrum or unpaired spectrum.

[0048] In an embodiment, the method may further include: receiving a random access response (RAR) from the network device, the RAR including an indication identifying resources in which the terminal device is allowed to send PUSCH data, wherein the network device determines that the RACH preamble is associated with the first random access procedure; and sending the PUSCH data in the identified resources.

[0049] In an embodiment, if the RACH preamble is to be sent according to the second random access procedure, the method may further include: in message A, sending PUSCH data in a predetermined resource set.

[0050] In an embodiment, the method may further include: determining whether the upcoming time resource is in the first time resource set or in the second time resource set; and if the upcoming time resource is in the first time resource set, sending a RACH preamble code according to the first random access procedure, and if the upcoming time resource is in the second time resource set, sending a RACH preamble code according to the second random access procedure.

[0051] In an embodiment, the method may further include: after sending a RACH preamble and PUSCH data according to the second random access procedure, or after sending only a RACH preamble according to the second access procedure, receiving a random access response (RAR) from the network device, wherein the network device determines that the RACH preamble is associated with the second random access procedure, but no PUSCH data is received or correctly decoded.

[0052] In an embodiment, the second time resource indication and the second frequency resource indication are configured by considering at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; a possible conflict between the second random access procedure and the first random access procedure; and a possible conflict between the second random access procedure and other signals other than the RACH preamble code.

[0053] In an embodiment, the time resource is a subframe if the RACH preamble is transmitted in a first frequency range, or a time slot if the RACH preamble is transmitted in a second frequency range.

[0054] In an embodiment, the first random access procedure is a four-step random access procedure, and the second random access procedure is a two-step random access procedure. In the two-step random access procedure, the terminal device sends a message A including a RACH preamble and PUSCH data.

[0055] According to a fifth aspect of the present disclosure, a terminal device is provided. The terminal device may include a transceiver, a processor and a memory. The memory contains instructions executable by the processor, whereby the terminal device is operable to implement the method according to the fourth aspect.

[0056] According to a sixth aspect of the present disclosure, a computer-readable storage medium is provided. Computer program instructions are stored on the computer-readable storage medium. When the computer program instructions are executed by a processor in a terminal device, the computer program instructions enable the terminal device to implement the method according to the fourth aspect above.

[0057] With the embodiments of the present disclosure, the time-frequency resources used for the RACH occasions in the two-step random access procedure are configured relative to the time-frequency resources used for the RACH occasions in the two-step random access procedure, so that they are shared or separated. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The above and other objects, features and advantages will become more apparent through the following description of embodiments with reference to the accompanying drawings, in which:

[0059] Figure 1A is a sequence diagram showing a four-step random access procedure;

[0060] Figure 1B is a sequence diagram illustrating a two-step random access procedure;

[0061] Figure 2 An example of RACH opportunity configuration in NR is shown;

[0062] Figure 3 An example is shown with one SSB per RACH opportunity;

[0063] Figure 4 An example is shown with 2 SSBs per RACH opportunity;

[0064] Figure 5 An example of mapping between SSB and RACH preamble is shown;

[0065] Figure 6 An example of associated preambles for CBRA and CFRA for each SSB per RACH opportunity is shown;

[0066] Figure 7 is a flow chart illustrating a method in a network device according to an embodiment of the present disclosure;

[0067] Figure 8 showing an example in which the time resources used for the two-step random access procedure are different from the time resources used for the four-step random access procedure;

[0068] Fig. 9 showing an example in which the frequency resources used for the two-step random access procedure are different from the frequency resources used for the four-step random access procedure;

[0069] Fig.10 is a flow chart illustrating a method in a terminal device according to an embodiment of the present disclosure;

[0070] Fig.11 is a block diagram of a network device according to another embodiment of the present disclosure;

[0071] Fig.12 is a block diagram of a network device according to another embodiment of the present disclosure;

[0072] Fig.13 is a block diagram of a terminal device according to an embodiment of the present disclosure;

[0073] Fig.14 is a block diagram of a terminal device according to another embodiment of the present disclosure;

[0074] Fig.15 An example of a wireless communication system in which embodiments of the present disclosure may be implemented is shown;

[0075] Fig.16 schematically illustrates a telecommunications network connected to a host computer via an intermediate network;

[0076] Fig.17 is a generalized block diagram of a host computer communicating with a user device via a base station over a partially wireless connection; and

[0077] Figures 18 to 21is a flow chart illustrating a method implemented in a communication system including a host computer, a base station and a user equipment. DETAILED DESCRIPTION

[0078] As used herein, the term "wireless communication network" refers to a network that complies with any suitable communication standard, such as NR, LTE Advanced (LTE-A), LTE, Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), etc. In addition, the communication between the terminal devices and the network devices in the wireless communication network can be implemented according to any suitable generation communication protocol, including but not limited to: Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE) and / or other suitable 1G (first generation), 2G (second generation), 2.5G, 2.75G, 3G (third generation), 4G (fourth generation), 4.5G, 5G (fifth generation) communication protocols, wireless local area network (WLAN) standards, such as IEEE 802.11 standards; and / or any other suitable wireless communication standards, such as Worldwide Interoperability for Microwave Access (WiMax), Bluetooth and / or ZigBee standards, and / or any other protocols currently known or to be developed in the future.

[0079] The term "network node" or "network device" refers to a device in a wireless communication network through which a terminal device accesses the network and receives services from it. A network node or network device refers to a base station (BS), an access point (AP) or any other suitable device in a wireless communication network. For example, a BS may be a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB) or a gNB, a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a repeater, a low-power node, such as a femto base station, a pico base station, etc. Another example of a network device may include a multi-standard radio (MSR) radio device (e.g., an MSR BS), a network controller (e.g., a radio network controller (RNC) or a base station controller (BSC)), a base transceiver station (BTS), a transmission point, a transmission node. However, more generally, a network device may represent any suitable device (or device group) that is capable of, configured, arranged and / or operable to enable and / or provide terminal device access to a wireless communication network or provide some services to a terminal device that has accessed the wireless communication network.

[0080] The term "terminal device" refers to any terminal device that can access a wireless communication network and receive services therefrom. As an example and not a limitation, a terminal device refers to a mobile terminal, a user equipment (UE) or other suitable device. A UE may be, for example, a user station (SS), a portable user station, a mobile station (MS) or an access terminal (AT). A terminal device may include, but is not limited to, a portable computer, a desktop computer, an image capture terminal device (e.g., a digital camera), a game terminal device, a music storage and playback device, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a personal digital assistant (PDA), a wearable terminal device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a notebook computer embedded device (LEE), a notebook computer mounted device (LME), a USB dongle, a smart device, a wireless customer premise equipment (CPE), etc. In the following description, the terms "terminal device", "terminal", "user equipment" and "UE" may be used interchangeably. As an example, a terminal device may represent a UE configured for communication according to one or more communication standards promulgated by the Third Generation Partnership Project (3GPP) (e.g., 3GPP's GSM, UMTS, LTE, and / or 5G standards). As used herein, "user equipment" or "UE" does not necessarily have a "user" in the sense of a human user who owns and / or operates the associated device. In some embodiments, a terminal device may be configured to send and / or receive information without direct human interaction. For example, a terminal device may be designed to send information to the network according to a predetermined schedule when triggered by an internal or external event, or in response to a request from a wireless communication network. In contrast, a UE may represent a device that is intended to be sold to a human user or operated by a human user but may not initially be associated with a specific human user.

[0081] The terminal device may support device-to-device (D2D) communication, for example by implementing the 3GPP standard for sidelink communication, and in this case may be referred to as a D2D communication device.

[0082] As another example, in an Internet of Things (IOT) scenario, a terminal device may represent a machine or other device that implements monitoring and / or measurement, and sends the results of such monitoring and / or measurement to another terminal device and / or network device. In this case, the terminal device may be a machine-to-machine (M2M) device, which may be referred to as a machine type communication (MTC) device in the 3GPP context. As a specific example, a terminal device may be a UE that implements the 3GPP Narrowband Internet of Things (NB-IoT) standard. Specific examples of such machines or devices are sensors, metering devices (such as electricity meters), industrial machinery, or household or personal appliances (such as refrigerators, televisions), personal wearable devices (such as watches, etc.). In other scenarios, a terminal device may represent a vehicle or other device that is capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0083] As used herein, downlink transmission refers to transmission from a network device to a terminal device, while uplink transmission refers to transmission in the opposite direction.

[0084] References in the specification to "one embodiment", "an embodiment", "an example embodiment", etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it should be considered that, whether or not explicitly described, it is within the knowledge of those skilled in the art to affect the feature, structure, or characteristic in conjunction with other embodiments.

[0085] It should be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed terms.

[0086] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms. It can be further understood that the terms "include", "comprise", "have", "contain", "include" and / or "comprising", when used herein, specify the presence of the features, elements and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0087] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0088] In NR, the time and frequency resources on which the RACH preamble is sent are defined as RACH opportunities.

[0089] The time resource and preamble format for the RACH preamble are configured by a RACH configuration index. For details on the RACH configuration index, reference may be made to the Third Generation Partnership Project (3GPP) Technical Specification (TS) 38.211, which is incorporated herein by reference in its entirety. The RACH configuration index indicates a row in a RACH configuration table specified in TS 38.211 (e.g., Tables 6.3.3.2-2, 6.3.3.2-3, 6.3.3.2-4 for FR1 (e.g., 450 MHz-6 GHz) paired spectrum, FR1 unpaired spectrum, and FR2 with unpaired spectrum (e.g., 24.25 GHz-52.6 GHz), respectively). A row in the RACH configuration table specifies a time domain RACH timing pattern for one RACH configuration period. One RACH configuration period may be 10, 20, 40, 80, or 160 ms.

[0090] A portion of Table 6.3.3.2-3 for RACH preamble format 0 for FR1 unpaired spectrum is copied to Table 1 below, where the x value indicates the RACH configuration period in terms of system frame number. The y value indicates the system frame in which the RACH opportunity is configured within each RACH configuration period. For example, if y is set to 0, it means that the RACH opportunity is configured only in the first frame of each RACH configuration period. The value in the "Subframe Number" column defines which subframes are configured with RACH opportunities. The value in the "Start Symbol" column is the symbol index. Determining the time resources for RACH opportunities for FR2 using Table 6.3.3.2-4 is similar, but 60kHz slots are used instead of subframes.

[0091] In the case of time division duplex (TDD), the semi-statically configured downlink part and / or the actually transmitted SSB may override and invalidate some time domain RACH opportunities defined in the RACH configuration table. More specifically, a RACH opportunity in the uplink part is always valid, and a RACH opportunity in the downlink part is valid as long as it does not precede or collide with an SSB in the RACH slot and it is at least N symbols after the last symbol of the downlink part and the SSB. N is 0 or 2, depending on the RACH format and the subcarrier spacing.

[0092]

[0093] Table 1 - RACH configuration for preamble format 0 for FR1 unpaired spectrum

[0094] In the frequency domain, NR supports multiple frequency multiplexed RACH opportunities in the same time domain RACH opportunity. This is mainly due to the support of analog beam scanning in NR, so that the RACH opportunities associated with one SSB are configured at the same time instance but different frequency locations. The RACH preamble can only be sent in the frequency resource given by the higher layer parameter msg1-FrequencyStart. The frequency resource n used for RACH opportunity RA ∈{0,1,…,M-1} (where M is equal to the higher layer parameter msg1-FDM) are numbered in ascending order starting from the lowest frequency within the initial active uplink bandwidth portion during initial access. Otherwise, n RA The RACH opportunities are numbered in increasing order starting from the lowest frequency within the active uplink bandwidth portion. The number M of RACH opportunities that are frequency division multiplexed (FDMed) in one time domain RACH opportunity may be 1, 2, 4 or 8.

[0095] Here, msg1-FDM and msg1-FrequencyStart are defined in the "RACH-ConfigGenetic" information element in 3GPP TS 38.211 as follows:

[0096] msg1-FDM

[0097] The number of RACH opportunities that are frequency-division multiplexed in one time instance. (See TS 38.211 Section 6.3.3.2)

[0098] msg1-FrequencyStart

[0099] The offset of the lowest RACH transmission opportunity in the frequency domain relative to PRB 0. This value is configured so that the corresponding RACH resource is completely within the bandwidth of the uplink bandwidth part (BWP). (See TS 38.211 section 6.3.3.2).

[0100] RACH-ConfigGeneric Information Element

[0101]

[0102] Figure 2 An example of RACH timing configuration in NR is shown. Figure 2 As shown, four RACH opportunities are frequency division multiplexed in one time instance.

[0103] In NR Rel-15, a maximum of 64 sequences can be used as RACH preambles per RACH opportunity in each cell. The RRC parameter totalNumberOfRA-Preambles determines how many of these 64 sequences are used as RACH preambles per RACH opportunity in each cell. These 64 sequences can be configured in the following way: first, include all available cyclic shifts of the root Zadoff-Chu sequence, and second, in order of increasing root index until 64 preambles are generated for the RACH opportunity.

[0104] NR Rel-15 supports one-to-one, one-to-many and many-to-one associations between SSB and RACH opportunities, such as Figure 3 and Figure 4 As shown, Figure 3 An example showing one SSB per RACH opportunity is shown. Figure 4 An example of 2 SSBs per RACH opportunity is shown.

[0105] The RACH preamble associated with each SSB is configured by the following two RRC parameters in RACH-ConfigCommon: ssb-perRACH-OccasionAndCB-PreamblesPerSSB and totalNumberOfRA-Preambles.

[0106] TS 38.213 Section 8.1 (incorporated herein by reference in its entirety) specifies the detailed mapping rules as follows:

[0107] The N SS / PBCH blocks associated with one PRACH opportunity and the R contention-based preambles for each SS / PBCH block for each valid PRACH opportunity are provided to the UE by ssb-perRACH-OccasionAndCB-PreamblesPerSSB. If N<1, one SS / PBCH block is mapped to 1 / N consecutive valid PRACH opportunities, and the R contention-based preambles with consecutive indices associated with the SS / PBCH block for each valid PRACH opportunity start at preamble index 0. If N≥1, the R contention-based preambles with consecutive indices associated with SS / PBCH block n (0≤n≤N-1) for each valid PRACH opportunity start at preamble index in Provided by totalNumberOfRA-Preambles and is an integer multiple of N.

[0108] The SS / PBCH block indices provided by ServingCellConfigCommon or ssb-PositionsInBurst in SIB1 are mapped to valid PRACH opportunities in the following order.

[0109] - First, in increasing order of preamble index within a single PRACH opportunity;

[0110] - Second, in the increasing order of frequency resource indexes of PRACH opportunities used for frequency reuse;

[0111] - Third, in increasing order of time resource indexes for PRACH opportunities time multiplexed within a PRACH slot;

[0112] - Fourth, in increasing order of index used for PRACH slots.

[0113] Starting from frame 0, the association period used to map SS / PBCH blocks to PRACH opportunities is the minimum value in the set determined by the PRACH configuration period according to Table 8.1-1, so that SS / PBCH blocks are mapped to the PRACH opportunity at least once in the association period, where the UE obtains the value of ssb-PositionsInBurst from ServingCellConfigCommon or SIB1 If after an integer number of SS / PBCH blocks to PRACH opportunity mapping cycles within the associated period, there are SS / PBCH blocks, then no SS / PBCH block is mapped to the PRACH opportunity set. The association pattern period includes one or more association periods and is determined so that the pattern between PRACH opportunities and SS / PBCH blocks repeats at most once every 160 milliseconds. PRACH opportunities that are not associated with SS / PBCH blocks after an integer number of association periods (if any) are not used for PRACH transmission.

[0114] In other words, the mapping between SSB and preamble is accomplished by consecutively associating M preambles to each SSB, where And the preamble is obtained in the following order:

[0115] - First, in increasing order of preamble index within a single PRACH opportunity;

[0116] - secondly, in increasing order of frequency resource indexes of PRACH opportunities used for frequency reuse; and

[0117] -Third, in ascending chronological order.

[0118] Figure 5 An example of mapping between SSB and RACH preamble is shown, where the number of SSBs is 8, M=32 (i.e., 2 SSBs per RACH opportunity), and the number of RACH opportunities frequency-division multiplexed in one time instance is 2. The RACH format is A3, i.e., 2 TD RACH opportunities per time slot. The RACH configuration period is 20ms, and there are 2 RACH time slots per configuration period.

[0119] For each SSB, the associated preambles for each RACH opportunity are further divided into two sets: for contention-based random access (CBRA) and contention-free random access (CFRA). The RRC parameter #CB-preambles-per-SSB signals the number of CBRA preambles per SSB per RACH opportunity. The preamble indexes for CBRA preambles and CFRA preambles are mapped consecutively for one SSB in one RACH opportunity. Figure 6 An example of associated preambles for CBRA and CFRA per SSB per RACH opportunity is shown.

[0120] For the two-step random access work item in NR Release 16, the latest agreement in the 3GPP RAN1#96b meeting on how to define the RACH timing (RO) and PUSCH timing for two-step random access is as follows.

[0121] protocol:

[0122] ● For the relationship between the PRACH resources of the two-step and four-step RACH processes, the network can flexibly configure the following options:

[0123] ○ Option 1: Configure separate ROs for two-step and four-step RACH;

[0124] ○ Option 2: Share RO but separate preambles for two-step and four-step RACH.

[0125] protocol:

[0126] ●Configure one or more PUSCH opportunities within the msgA PUSCH configuration period.

[0127] ○FFS msgA PUSCH configuration period, for example:

[0128] ■For option 1 with separate PUSCH configuration, the msgA PUSCH configuration period may be the same as the PRACH configuration period or may be different from the PRACH configuration period;

[0129] ■ For option 2 of PUSCH configuration with relative position, the msgA PUSCH configuration period is the PRACH configuration period.

[0130] As can be seen from the above protocol, in one option of the PRACH configuration, the preambles for the two-step and four-step RACH processes are in separate ROs, and therefore in separate OFDM symbols and / or separate subcarrier sets, while in another option, the preambles for the two-step and four-step RACH processes can be in one RO, and therefore in the same OFDM symbol and subcarrier set.

[0131] It can also be seen from the above protocol that the PUSCH opportunity carrying the msgA data part occurs in the resources pre-configured in the two-step RACH process, which is opposite to the msg3 transmission, which occurs in the resources scheduled by the RAR in the four-step RACH process.

[0132] Hereinafter, the specification is described by taking a four-step random access procedure as a first random access procedure and a two-step random access procedure as a second random access procedure.

[0133] Hereinafter, "RACH preamble" refers to a PRACH preamble for a four-step random access procedure, or a msgA preamble for a two-step random access procedure.

[0134] Figure 7 7 is a flow chart showing a method 700 according to an embodiment of the present disclosure. The method 700 may be implemented at a network device (eg, a gNB).

[0135] In step S710, the network device sends a random access channel (RACH) timing configuration to the terminal device. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send the RACH preamble according to the second random access procedure.

[0136] Here, the random access opportunity (or specifically, RACH opportunity (RO)) refers to a time-frequency resource for transmitting a RACH preamble.

[0137] In step S720, the network device receives a RACH preamble code sent from the terminal device according to the RACH timing configuration.

[0138] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0139] In an embodiment, the first time resource indication has the form of a first RACH configuration table, and the second time resource indication has the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0140] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion of the RACH configuration table and the first time resource indication identifies a different portion of the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0141] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows and / or columns in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or different rows in the new RACH configuration.

[0142] For example, table set A (i.e., an existing RACH configuration table configured for a four-step random access procedure) is reused for table set B. A separate RACH configuration index is configured for a two-step RACH procedure, which indicates a different row in the associated RACH configuration table compared to a row in the four-step random access procedure, so that the OFDM symbols occupied by valid RACH opportunities for the two-step random access are all different from the OFDM symbols occupied by valid four-step RACH opportunities. Figure 8 An example is shown in which the time resources used for the two-step random access procedure are different from the time resources used for the four-step random access procedure.

[0143] The benefit of using different OFDM symbols and / or different subcarriers for the two-step and four-step RACH procedures is that incorrect operation of Rel-15 UEs that are not capable of two-step RACH operation can be avoided. If a Rel-15 UE sends a preamble in a symbol and subcarrier that can be used for two-step operation, then even though the network will attempt to receive a PUSCH, the Rel-15 UE will not send a PUSCH containing msgA, because a Rel-16 UE capable of two-step operation will send this PUSCH when sending a preamble in that symbol.

[0144] In the example, frequency resources are configured separately.

[0145] In an embodiment, the second frequency resource indication includes: a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" may be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities frequency-division multiplexed in at least one time resource for the first random access procedure, the preamble format for the second random access procedure, the frequency band for the second random access procedure, and the RACH time configuration for the second random access procedure.

[0146] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In an embodiment, the PRB is the first PRB in the bandwidth part containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is a PRB whose index may be the minimum or maximum index in the first frequency resource set. When the UE receives the parameter included in the second frequency resource indication, it can determine the lowest RACH opportunity in the second frequency resource set in at least one of the following ways: adding the offset to the index of the first PRB in the bandwidth part containing the second frequency resource set, adding the offset to the index of the PRB whose index is the minimum index in the first frequency resource set, and adding the offset to the index of the PRB whose index is the maximum index in the first frequency resource set.

[0147] For example, the parameter "msgA_preamble-FrequencyStart" may be configured in the "RACH-ConfigGeneric information element". As another example, the offset value FrequencyStartOffset may be configured in the "RACH-ConfigGeneric information element". FrequencyStartOffset may be added to the starting frequency msg1-FrequencyStart of the first RO for the four-step random access procedure in one time instance to determine the starting frequency msgA_preamble-FrequencyStart of the first RO for the two-step random access procedure in one time instance, i.e.:

[0148] msgA_preamble-FrequencyStart=msg1-FrequencyStart+FrequencyStartOffset

[0149] The FrequencyStartOffset may be a fixed value or a predetermined value or RRC configured. The entire frequency band used for the RO of the four-step process in one time instance depends on the preamble format and the number of ROs frequency-division multiplexed in one time instance.

[0150] Fig. 9 An example is shown where the second frequency resource indication includes parameter "msgA_preamble-FDM" = 1 and does not include a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB.The RO for the two-step random access procedure starts after the last RO for the four-step random access procedure.

[0151] In an embodiment, the method 700 may further include: step S730, for determining whether the received RACH preamble is associated with the first random access procedure or the second random access procedure; and step S740, for sending a random access response (RAR) to the terminal device in response to determining that the received RACH preamble is associated with the first random access procedure. That is, if the terminal device (e.g., UE) sends the RACH preamble according to the four-step random access procedure, the network device (e.g., gNB) should follow the four-step random access procedure to send the RAR to the terminal device after receiving the RACH preamble.

[0152] In an embodiment, the method 700 may further include step S750 for sending a random access response (RAR) to the terminal device in response to receiving a RACH preamble without receiving PUSCH data, wherein the RACH preamble is associated with the second random access procedure. That is, even if the terminal device (e.g., UE) sends a RACH preamble according to the two-step random access procedure, the network device (e.g., gNB) can correctly decode the RACH preamble and know that the RACH preamble is sent according to the two-step random access procedure, but no PUSCH data is received or the PUSCH data cannot be decoded, and it sends a random access response (RAR) to the terminal device by following the two-step random access procedure.

[0153] When the two-step RACH occasions (RO) are configured separately, the second time resource indication and the second frequency resource indication are configured by the network device taking into account at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflict between the second random access procedure and the first random access procedure; and possible conflict between the second random access procedure and other signals other than the RACH preamble code.

[0154] For example, when only a small number of terminal devices are expected to use the two-step random access process, a periodicity for the two-step random access process can be configured that is larger than the periodicity for the four-step random access process, and when a large number of terminal devices are expected to use the two-step random access process, a periodicity that is smaller than the periodicity for the four-step random access process can be configured.

[0155] As another example, when the two-step RO partially or completely overlaps with the four-step RO, a predetermined rule may be defined, wherein the rule may be: when the overlap occurs, only the four-step random access procedure is allowed on the four-step RO, and the two-step random access procedure will be blocked. That is, the terminal device (e.g., UE) determines whether the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set; and in response to determining that the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set, it sends the RACH preamble in the time-frequency resources according to the four-step random access procedure.

[0156] As described above, the Rel-15 NR RACH configuration identifies the RACH opportunity based on the subframe and frequency resource in which the RACH opportunity is transmitted. A large number (e.g., 256) of configurations are defined, which differ depending on whether they are used in FR1, FR2, paired or unpaired spectrum. In order to minimize design complexity, it may be desirable to reuse the set of configurations defined for Rel-15 to implement two-step RACH in Rel-16. It is possible that a UE capable of a two-step random access procedure will need to transmit according to a four-step as well as a two-step random access procedure. Since different Rel-15 RACH configurations can use the same subframe, the two RACH configurations for the two-step and four-step random access procedures may conflict, indicating that the RACH opportunity should carry a preamble for both two-step and four-step operation. Completely excluding this combination of RACH configurations may significantly reduce the scheduling flexibility of the combination of two-step and four-step random access procedures in a cell and may therefore be undesirable. Therefore, a mechanism may be needed to resolve conflicts between two-step and four-step RACH configurations. Resources designated for use in a four-step random access procedure should not be used for a two-step operation as this would be inconsistent with the UE using resources for a four-step random access procedure. Therefore, if the two-step and four-step RACH configurations conflict, the UE shall use resources designated for both the two-step and four-step random access procedures for the four-step random access procedure.

[0157] In an embodiment, if the RACH preamble code is sent in a first frequency range (e.g., frequencies below 6 GHz), the time resource is a subframe, or if the RACH preamble code is sent in a second frequency range (e.g., frequencies above 6 GHz), the time resource is a time slot (e.g., a 60 kHz time slot).

[0158] When analog beam scanning is used for SSB and MSG B transmission, this method is beneficial in terms of lower latency because both a UE capable of two-step random access procedure and a UE capable of four-step random access procedure associated with the same best SSB can send preamble codes simultaneously.

[0159] In another embodiment, the second time resource indication and the second frequency resource indication may indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

[0160] That is, the four-step RO is shared by the two-step RO, and the RO set from the four-step RA is shared.

[0161] In an embodiment, the second time resource indication and the second frequency resource indication further indicate an association period, and the association period may be configured by the network device taking into account the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration. For example, only one RO set is used for the two-step random access procedure in a certain association period for mapping the SSB to the RACH opportunity of the four-step random access procedure.

[0162] In an embodiment, the second time resource indication and the second frequency resource indication are sent via an RRC message.

[0163] The subset may be a fixed subset of the RO from the four-step random access procedure or may be indicated via RRC signaling. In an embodiment, the network device may configure a subset of time resources or frequency resources by considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire SSB set in one SSB burst set; the number of SSBs actually transmitted; the RACH configuration index, and whether the spectrum type is paired spectrum or unpaired spectrum.

[0164] Fig.10 1 is a flow chart showing a method 1000 according to an embodiment of the present disclosure. The method 1000 may be implemented in a terminal device (eg, UE).

[0165] In step S1010, the terminal device receives a random access channel (RACH) timing configuration from the network device. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure.

[0166] In step S1020, the terminal device sends a RACH preamble according to the RACH timing configuration.

[0167] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0168] In an embodiment, the first time resource indication has the form of a first RACH configuration table, and the second time resource indication has the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0169] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion of the RACH configuration table and the first time resource indication identifies a different portion of the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0170] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows and / or columns in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or different rows in the new RACH configuration.

[0171] For example, table set A (i.e., an existing RACH configuration table configured for a four-step random access procedure) is reused for table set B. A separate RACH configuration index is configured for a two-step RACH procedure, which indicates a row in the associated RACH configuration table that is different from a row for the four-step random access procedure, so that the OFDM symbols occupied by valid RACH opportunities for the two-step random access are all different from the OFDM symbols occupied by valid four-step RACH opportunities. Figure 8 An example is shown in which the time resources used for the two-step random access procedure are different from the time resources used for the four-step random access procedure.

[0172] The benefit of using different OFDM symbols and / or different subcarriers for the two-step and four-step RACH procedures is that erroneous operation of Rel-15 UEs that are not capable of two-step RACH operation can be avoided. If a Rel-15 UE sends a preamble in a symbol and subcarrier that can be used for two-step operation, then even though the network will try to receive that PUSCH, it will not send a PUSCH containing msgA, because a Rel-16 UE capable of two-step operation will send a PUSCH when sending a preamble in that symbol.

[0173] In the example, frequency resources are configured separately.

[0174] In an embodiment, the second frequency resource indication includes: a parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" can be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource (for example, by a network device) is configured by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource for the first random access process, the preamble format for the second random access process, the frequency band for the second random access process, and the RACH time configuration for the second random access process. In yet another embodiment, such a parameter does not exist in the second frequency resource indication. The terminal device can determine the number of RACH opportunities that are frequency-division multiplexed in at least one time resource for the second random access process by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource for the first random access process, the preamble format for the second random access process, the frequency band for the second random access process, and the RACH time configuration for the second random access process.

[0175] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In the example, the PRB is the first PRB in the bandwidth part containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is the PRB whose index can be the minimum or maximum index in the first frequency resource set. Upon receiving the parameter included in the second frequency resource indication, the terminal device can determine the lowest RACH opportunity in the second frequency resource set by at least one of the following ways: adding an offset to the index of the first PRB in the bandwidth part containing the second frequency resource set, adding an offset to the index of the PRB whose index is the minimum index in the first frequency resource set, and adding an offset to the index of the PRB whose index is the maximum index in the first frequency resource set. In another example, there is no such parameter defining the offset of the lowest RACH opportunity relative to the index of the PRB in the second frequency resource indication. The terminal device can determine the lowest RACH opportunity in the second frequency resource set by adding one or more to the index of the PRB whose index is the maximum index in the first frequency resource set, as configured by default.

[0176] In another embodiment, the second time resource indication and the second frequency resource indication may indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

[0177] That is, the four-step RO is shared by the two-step RO, and the RO set from the four-step RA is shared.

[0178] As another example, when the two-step RO partially or completely overlaps with the four-step RO, a predetermined rule may be defined, wherein the rule may be that when the overlap occurs, only the four-step random access procedure is allowed on the four-step RO, and the two-step random access procedure will be blocked. That is, at step S1030, the terminal device (e.g., UE) determines whether the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set; and if so, then at step 1020, it sends the RACH preamble in the time-frequency resources according to the four-step random access procedure.

[0179] In an embodiment, the second time resource indication and the second frequency resource indication further indicate an association period, and the association period may be configured by (e.g., a network device) considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration. For example, only one RO set is used for the two-step random access procedure in a certain association period for mapping the SSB to the RACH opportunity of the four-step random access procedure.

[0180] In an embodiment, the second time resource indication and the second frequency resource indication are received via an RRC message.

[0181] The subset may be a fixed subset of the RO from the four-step random access procedure, or indicated via RRC signaling. In an embodiment, the subset of time resources or frequency resources is configured by (e.g., a network device) considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire SSB set in one SSB burst set; the number of SSBs actually transmitted; the RACH configuration index; and whether the spectrum type is paired spectrum or unpaired spectrum.

[0182] In an embodiment, the method 1000 further includes: step S1040, for receiving a random access response (RAR) from a network device, the random access response (RAR) including an indication identifying resources in which the terminal device is allowed to send PUSCH data, wherein the network device determines that the RACH preamble is associated with the first random access procedure; and step S1050, for sending PUSCH data in the identified resources. That is, the terminal device uses a four-step random access procedure to access the network device.

[0183] In an embodiment, if the terminal device is to send a RACH preamble according to the second random access procedure, the method 1000 further includes: in message A, a step of sending PUSCH data in a predetermined resource set. That is, the terminal device uses a two-step random access procedure to access the network device. It should be noted that if the terminal device uses a two-step random access procedure to access the network device, the operation of sending PUSCH data in the predetermined resource set occurs simultaneously with the operation of sending the RACH preamble.

[0184] In an embodiment, even if a terminal device (e.g., UE) sends a RACH preamble according to a two-step random access procedure, the network device (e.g., gNB) can correctly decode the RACH preamble, and knowing that the RACH preamble is sent according to the two-step random access procedure, but no PUSCH data is received or the PUSCH data cannot be decoded, it sends a random access response (RAR) to the terminal device by following the two-step random access procedure. Therefore, after the RACH preamble and the PUSCH data are sent according to the second random access procedure or only the RACH preamble is sent according to the second access procedure, the terminal device receives a random access response (RAR) from the network device, wherein the network device determines that the RACH preamble is associated with the second random access procedure, but no PUSCH data is received or correctly decoded. That is, the terminal device cannot access the network by adopting the two-step random access procedure, and then follows the four-step random access procedure to access the network device.

[0185] Since the two-step and four-step ROs are time multiplexed and can be separated by tens of milliseconds, a UE that is required to use only one of the two-step or four-step ROs needs to wait until the required RO arrives, which is contrary to the low-latency behavior expected in two-step RACH operation. Therefore, in some embodiments, the UE is configured to use both the first and second RO sets, select one of the first and second RO sets to send a RACH preamble in, and then follow the RACH procedure associated with the RO in which the RACH preamble is sent. The UE determines whether the upcoming time resources are in the first time resource set or the second time resource set, and if the upcoming time resources are in the first time resource set, sends the RACH preamble according to the first random access procedure, and if the upcoming time resources are in the second time resource set, sends the RACH preamble according to the second random access procedure. The UE can use a criterion to select the RO, where the criterion can be to send the RACH preamble in the next available RO after the time when it determines that RACH transmission is required.

[0186] The two-step and four-step random access procedures in a cell may be used by different numbers of UEs, so it may be desirable to control the load on the resources used by the two-step and four-step random access procedures. One way to achieve this is to constrain UEs capable of the two-step random access procedure to use the two-step random access procedure in a first attempt of the random access procedure, and if the first attempt is unsuccessful, allow the UE to use both the two-step and four-step resources in a second attempt using the four-step random access procedure. In this case, the criteria for RO selection may be: select an RO from the second RO set for the first random access attempt, determine that a second random access attempt is required, and then select an RO from the first or second RO set for the second random access attempt.

[0187] In some embodiments, the two-step RO is configured separately (e.g., by a network device), and the second time resource indication and the second frequency resource indication are configured by the network device taking into account at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflicts between the second random access procedure and the first random access procedure; and possible conflicts between the second random access procedure and signals other than the RACH preamble.

[0188] For example, when only a small number of terminal devices are expected to use the two-step random access process, a periodicity for the two-step random access process can be configured that is larger than the periodicity for the four-step random access process, and when a large number of terminal devices are expected to use the two-step random access process, a periodicity that is smaller than the periodicity for the four-step random access process can be configured.

[0189] In an embodiment, if the RACH preamble code is sent in a first frequency range (e.g., frequencies below 6 GHz), the time resource is a subframe, or if the RACH preamble code is sent in a second frequency range (e.g., frequencies above 6 GHz), the time resource is a time slot (e.g., a 60 kHz time slot).

[0190] Corresponding to the method 700 described above, a network device is provided. Fig.11 is a block diagram of a network device 1100 according to an embodiment of the present disclosure.

[0191] like Fig.11 As shown, the network device 1100 includes a sending unit 1120, which is configured to send a random access channel (RACH) timing configuration to the terminal device. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access process; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access process; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access process; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access process.

[0192] The network device 1100 further includes a receiving unit 1110 configured to receive a RACH preamble code sent from a terminal device according to a RACH timing configuration.

[0193] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0194] In an embodiment, the first time resource indication is in the form of a first RACH configuration table, and the second time resource indication is in the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0195] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a row in the RACH configuration table that is different from the row identified by the first time resource indication in the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0196] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or rows in the new RACH configuration.

[0197] In an embodiment, the second frequency resource indication includes: a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" may be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities frequency-division multiplexed in at least one time resource for the first random access procedure, the preamble format for the second random access procedure, the frequency band for the second random access procedure, and the RACH time configuration for the second random access procedure.

[0198] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In the example, the PRB is the first PRB in the bandwidth portion containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is a PRB whose index can be the minimum or maximum index in the first frequency resource set. Upon receiving the parameter included in the second frequency resource indication, the UE may determine the lowest RACH opportunity in the second frequency resource set in at least one of the following ways: adding an offset to the index of the first PRB in the bandwidth portion containing the second frequency resource set, adding an offset to the index of the PRB whose index is the minimum index in the first frequency resource set, and adding an offset to the index of the PRB whose index is the maximum index in the first frequency resource set.

[0199] In an embodiment, the network device 1100 may further include a determining unit 1130 configured to determine whether the received RACH preamble is associated with the first random access procedure or the second random access procedure. The sending unit 1120 is configured to: in response to determining that the received RACH preamble is associated with the first random access procedure, send a random access response (RAR) to the terminal device. That is, if the terminal device (e.g., UE) sends the RACH preamble according to the four-step random access procedure, the network device 1100 should follow the four-step random access procedure to send the RAR to the terminal device after receiving the RACH preamble.

[0200] In an embodiment, the transmitting unit 1120 is further configured to: in response to receiving a RACH preamble but not receiving PUSCH data, send a random access response (RAR) to the terminal device, wherein the RACH preamble is associated with the second random access procedure. That is, even if the terminal device (e.g., UE) sends a RACH preamble according to the two-step random access procedure, the network device 1100 can correctly decode the RACH preamble and know that the RACH preamble is sent according to the two-step random access procedure, but does not receive PUSCH data or cannot decode PUSCH data, and it sends a random access response (RAR) to the terminal device by following the two-step random access procedure.

[0201] In an embodiment, the two-step RACH opportunities (RO) are configured separately, and the determination unit 1130 is further configured to determine the second time resource indication and the second frequency resource indication by considering at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflicts between the second random access procedure and the first random access procedure; and possible conflicts between the second random access procedure and other signals other than the RACH preamble code.

[0202] For example, when only a small number of terminal devices are expected to use the two-step random access process, a periodicity for the two-step random access process can be configured that is larger than the periodicity for the four-step random access process, and when a large number of terminal devices are expected to use the two-step random access process, a periodicity that is smaller than the periodicity for the four-step random access process can be configured.

[0203] Units 1110-1130 may be implemented as a pure hardware solution or a combination of software and hardware, for example, by one or more of: a processor or microprocessor and sufficient software and memory for storing the software, a programmable logic device (PLD) or other electronic components or processing circuits (which are configured to implement the above and, for example, Figure 7 ).

[0204] Fig.12 is a block diagram of a network device 1200 according to another embodiment of the present disclosure.

[0205] The network device 1200 includes a transceiver 1210, a processor 1220, and a memory 1230. The memory 1230 contains instructions that can be executed by the processor 1220, so that the network device 1200 can be operated to implement, for example, the above-mentioned Figure 7 Actions of the described process. In particular, the memory 1230 contains instructions executable by the processor 1220, whereby the network device 1200 is operable to send a random access channel (RACH) timing configuration to the terminal device, and to receive a RACH preamble sent from the terminal device according to the RACH timing configuration. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure.

[0206] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0207] In an embodiment, the first time resource indication has the form of a first RACH configuration table, and the second time resource indication has the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0208] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a row in the RACH configuration table that is different from the row identified by the first time resource indication in the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0209] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or different rows in the new RACH configuration.

[0210] In an embodiment, the second frequency resource indication includes: a parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" may be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource for the first random access procedure, the preamble format for the second random access procedure, the frequency band for the second random access procedure, and the RACH time configuration for the second random access procedure.

[0211] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In an embodiment, the PRB is the first PRB in the bandwidth portion containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is a PRB whose index may be the minimum or maximum index in the first frequency resource set. Upon receiving the parameter included in the second frequency resource indication, the UE may determine the lowest RACH opportunity in the second frequency resource set in at least one of the following ways: adding an offset to the index of the first PRB in the bandwidth portion containing the second frequency resource set, adding an offset to the index of the PRB whose index is the minimum index in the first frequency resource set, and adding an offset to the index of the PRB whose index is the maximum index in the first frequency resource set.

[0212] In an embodiment, the memory 1230 contains instructions executable by the processor 1220, whereby the network device 1200 can further operate to: determine whether the received RACH preamble is associated with the first random access procedure or the second random access procedure, and in response to determining that the received RACH preamble is associated with the first random access procedure, send a random access response (RAR) to the terminal device. That is, if the terminal device (e.g., UE) sends the RACH preamble according to the four-step random access procedure, the network device 1200 should follow the four-step random access procedure to send the RAR to the terminal device after receiving the RACH preamble.

[0213] In an embodiment, the memory 1230 contains instructions executable by the processor 1220, whereby the network device 1200 may further operate to: in response to receiving a RACH preamble but not receiving PUSCH data, send a random access response (RAR) to the terminal device, wherein the RACH preamble is associated with the second random access procedure. That is, even if the terminal device (e.g., UE) sends a RACH preamble according to the two-step random access procedure, the network device 1200 correctly decodes the RACH preamble and knows that the RACH preamble is sent according to the two-step random access procedure, but does not receive PUSCH data or cannot decode the PUSCH data, and it sends a random access response (RAR) to the terminal device by following the two-step random access procedure.

[0214] In an embodiment, the two-step RACH opportunities (RO) are configured separately, and the memory 1230 contains instructions executable by the processor 1220, whereby the network device 1200 can further operate to configure the second time resource indication and the second frequency resource indication by considering at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflicts between the second random access procedure and the first random access procedure; and possible conflicts between the second random access procedure and other signals other than the RACH preamble code.

[0215] For example, when only a small number of terminal devices are expected to use the two-step random access process, a periodicity for the two-step random access process can be configured that is larger than the periodicity for the four-step random access process, and when a large number of terminal devices are expected to use the two-step random access process, a periodicity that is smaller than the periodicity for the four-step random access process can be configured.

[0216] Corresponding to the method 1000 described above, a terminal device is provided. Fig.13 is a block diagram of a terminal device 1300 according to an embodiment of the present disclosure.

[0217] like Fig.13 As shown, the terminal device 1300 includes a receiving unit 1110, which is configured to receive a random access channel (RACH) timing configuration from a network device. The terminal device 1300 also includes a sending unit 1320, which is configured to send a RACH preamble according to the RACH timing configuration. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access process; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access process; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access process; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access process.

[0218] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0219] In an embodiment, the first time resource indication has the form of a first RACH configuration table, and the second time resource indication has the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0220] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion of the RACH configuration table and the first time resource indication identifies a different portion of the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0221] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows and / or columns in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or different rows in the new RACH configuration.

[0222] In an embodiment, the second frequency resource indication includes: a parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" can be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource is configured (for example, by a network device) by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the first random access procedure, the preamble format used for the second random access procedure, the frequency band used for the second random access procedure, and the RACH time configuration used for the second random access procedure. In yet another embodiment, such a parameter is not present in the second frequency resource indication. The terminal device can determine the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the second random access procedure by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the first random access procedure, the preamble format used for the second random access procedure, the frequency band used for the second random access procedure, and the RACH time configuration used for the second random access procedure.

[0223] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In an example, the PRB is the first PRB in the bandwidth part containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is the PRB whose index can be the minimum or maximum index in the first frequency resource set. Upon receiving the parameter included in the second frequency resource indication, the terminal device 1300 can determine the lowest RACH opportunity in the second frequency resource set by at least one of the following ways: adding an offset to the index of the first PRB in the bandwidth part containing the second frequency resource set, adding an offset to the index of the PRB whose index is the minimum index in the first frequency resource set, and adding an offset to the index of the PRB whose index is the maximum index in the first frequency resource set. In another example, there is no such parameter defining the offset of the lowest RACH opportunity relative to the index of the PRB in the second frequency resource indication. The terminal device 1300 can determine the lowest RACH opportunity in the second frequency resource set by adding one or more to the index of the PRB whose index is the maximum index in the first frequency resource set, as configured by default.

[0224] In another embodiment, the second time resource indication and the second frequency resource indication may indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

[0225] That is, the four-step RO is shared by the two-step RO, and the RO set from the four-step RA is shared.

[0226] As another example, when the two-step RO partially or completely overlaps with the four-step RO, a predetermined rule may be defined, wherein the rule may be that when the overlap occurs, only the four-step random access procedure is allowed on the four-step RO, and the two-step random access procedure will be blocked. That is, the terminal device 1300 may also include a determination unit 1330, which is configured to: determine whether the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set. The sending unit 1320 is configured to: if the determination unit 1330 determines that the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set, then send the RACH preamble in the time-frequency resource according to the four-step random access procedure.

[0227] In an embodiment, the second time resource indication and the second frequency resource indication further indicate an association period, and the association period may be configured by (e.g., a network device) considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration. For example, only one RO set is used for the two-step random access procedure in a certain association period for mapping the SSB to the RACH opportunity of the four-step random access procedure.

[0228] In an embodiment, the second time resource indication and the second frequency resource indication are received via an RRC message.

[0229] The subset may be a fixed subset of the RO from the four-step random access procedure, or indicated via RRC signaling. In an embodiment, the subset of time resources or frequency resources is configured by (e.g., a network device) considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire SSB set in one SSB burst set; the number of SSBs actually transmitted; the RACH configuration index; and whether the spectrum type is paired spectrum or unpaired spectrum.

[0230] In an embodiment, the receiving unit 1310 is further configured to receive a random access response (RAR) from the network device, the random access response (RAR) including an indication identifying resources in which the terminal device is allowed to send PUSCH data, wherein the network device determines that the RACH preamble is associated with the first random access procedure, and the sending unit 1320 is further configured to send PUSCH data in the identified resources. That is, the terminal device 1300 uses a four-step random access procedure to access the network device.

[0231] In an embodiment, if the sending unit 1320 is to send a RACH preamble according to the second random access procedure, the sending unit 1320 is further configured to send PUSCH data in a predetermined resource set in message A. That is, the terminal device 1300 uses a two-step random access procedure to access the network device. It should be noted that if the terminal device 1300 uses a two-step random access procedure to access the network device, the operation of sending PUSCH data in a predetermined resource set occurs simultaneously with the operation of sending the RACH preamble.

[0232] In an embodiment, even if the terminal device 1300 sends a RACH preamble according to a two-step random access procedure, the network device (e.g., gNB) can correctly decode the RACH preamble and know that the RACH preamble is sent according to the two-step random access procedure, but no PUSCH data is received or the PUSCH data cannot be decoded, and it sends a random access response (RAR) to the terminal device by following the two-step random access procedure. Therefore, the sending unit 1320 is configured to receive a random access response (RAR) from the network device after the RACH preamble and PUSCH data are sent according to the second random access procedure or only the RACH preamble is sent according to the second access procedure, wherein the network device determines that the RACH preamble is associated with the second random access procedure, but no PUSCH data is received or correctly decoded. That is, the terminal device 1300 fails to access the network by adopting a two-step random access procedure, and then follows a four-step random access procedure to access the network device.

[0233] Since two-step and four-step ROs are time multiplexed and can be separated by tens of milliseconds, a terminal device that is required to use only one of the two-step or four-step ROs needs to wait until the required RO arrives, which is contrary to the low-latency behavior expected in two-step RACH operation. Therefore, in some embodiments, the terminal device is configured to use both the first and second RO sets, select one of the first and second RO sets to send a RACH preamble in, and then follow the random access procedure associated with the RO in which the RACH preamble is sent. The terminal device 1300 determines whether the upcoming time resources are in the first time resource set or the second time resource set, and if the upcoming time resources are in the first time resource set, sends the RACH preamble according to the first random access procedure, and if the upcoming time resources are in the second time resource set, sends the RACH preamble according to the second random access procedure. The terminal device 1300 can use a criterion to select the RO, where the criterion can be to send the RACH preamble in the next available RO after the time at which it determines that a RACH transmission is required.

[0234] The two-step and four-step random access procedures in a cell may be used by different numbers of terminal devices, so it may be desirable to control the load on the resources used by the two-step and four-step random access procedures. One way to achieve this is to restrict terminal devices capable of the two-step random access procedure to use the two-step random access procedure in a first attempt at the random access procedure, and then, if the first attempt is unsuccessful, allow the terminal device to use both the two-step and four-step resources in a second attempt using the four-step random access procedure. In this case, the criteria for RO selection may be: selecting an RO from the second RO set for the first random access attempt, determining that a second random access attempt is required, and then selecting an RO from the first or second RO set for the second random access attempt.

[0235] In some embodiments, the two-step RO is configured separately (e.g., by a network device), and the second time resource indication and the second frequency resource indication are configured by the network device taking into account at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflicts between the second random access procedure and the first random access procedure; and possible conflicts between the second random access procedure and signals other than the RACH preamble.

[0236] For example, when only a small number of terminal devices are expected to use the two-step random access process, a periodicity for the two-step random access process can be configured that is larger than the periodicity for the four-step random access process, and when a large number of terminal devices are expected to use the two-step random access process, a periodicity that is smaller than the periodicity for the four-step random access process can be configured.

[0237] In an embodiment, if the RACH preamble code is sent in a first frequency range (e.g., frequencies below 6 GHz), the time resource is a subframe, or if the RACH preamble code is sent in a second frequency range (e.g., frequencies above 6 GHz), the time resource is a time slot (e.g., a 60 kHz time slot).

[0238] Units 1310-1330 may be implemented as a pure hardware solution or a combination of software and hardware, for example, by one or more of a processor or microprocessor and sufficient software and memory for storing the software, a programmable logic device (PLD) or other electronic component or processing circuit (which is configured to implement the above and, for example, Fig.10 ).

[0239] Fig.14 is a block diagram of a terminal device 1400 according to another embodiment of the present disclosure.

[0240] The terminal device 1400 includes a transceiver 1410, a processor 1420, and a memory 1430. The memory 1430 contains instructions that can be executed by the processor 1420, so that the terminal device 1400 can be operated to implement, for example, the above-mentioned Fig.10 Actions of the described process. In particular, the memory 1430 contains instructions executable by the processor 1420, whereby the terminal device 1400 is operable to receive a random access channel (RACH) timing configuration from a network device and send a RACH preamble according to the RACH timing configuration. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure.

[0241] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0242] In an embodiment, the first time resource indication has the form of a first RACH configuration table, and the second time resource indication has the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0243] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion of the RACH configuration table and the first time resource indication identifies a different portion of the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0244] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows and / or columns in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or different rows in the new RACH configuration.

[0245] In an embodiment, the second frequency resource indication includes: a parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" can be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities that are frequency-division multiplexed in at least one time resource is configured (for example, by a network device) by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the first random access procedure, the preamble format used for the second random access procedure, the frequency band used for the second random access procedure, and the RACH time configuration used for the second random access procedure. In yet another embodiment, such a parameter is not present in the second frequency resource indication. The terminal device 1400 can determine the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the second random access process by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the first random access process, the preamble format used for the second random access process, the frequency band used for the second random access process, and the RACH time configuration used for the second random access process.

[0246] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In an example, the PRB is a first PRB in a bandwidth portion containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is a PRB whose index can be the smallest or largest index in the first frequency resource set. Upon receiving the parameter included in the second frequency resource indication, the terminal device 1400 can determine the lowest RACH opportunity in the second frequency resource set by at least one of the following ways: adding an offset to the index of the first PRB in the bandwidth portion containing the second frequency resource set, adding an offset to the index of the PRB whose index is the smallest index in the first frequency resource set, and adding an offset to the index of the PRB whose index is the largest index in the first frequency resource set. In another example, there is no such parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB in the second frequency resource indication. The terminal device 1400 can determine the lowest RACH opportunity in the second frequency resource set by adding one or more to the index of the PRB whose index is the largest index in the first frequency resource set, as configured by default.

[0247] In another embodiment, the second time resource indication and the second frequency resource indication may indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

[0248] That is, the four-step RO is shared by the two-step RO, and the RO set from the four-step RA is shared.

[0249] As another example, when the two-step RO partially or completely overlaps with the four-step RO, a predetermined rule may be defined, wherein the rule may be that when the overlap occurs, only the four-step random access procedure is allowed on the four-step RO, and the two-step random access procedure will be blocked. That is, the memory 1430 contains instructions executable by the processor 1420, whereby the terminal device 1400 may further operate to: determine whether the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set; and if so, send the RACH preamble in the time-frequency resources according to the four-step random access procedure.

[0250] In an embodiment, the second time resource indication and the second frequency resource indication further indicate an association period, and the association period may be configured by (e.g., a network device) considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration. For example, only one RO set is used for the two-step random access procedure in a certain association period for mapping the SSB to the RACH opportunity of the four-step random access procedure.

[0251] In an embodiment, the second time resource indication and the second frequency resource indication are received via an RRC message.

[0252] The subset may be a fixed subset of the RO from the four-step random access procedure, or indicated via RRC signaling. In an embodiment, the subset of time resources or frequency resources is configured by (e.g., a network device) considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire SSB set in one SSB burst set; the number of SSBs actually transmitted; the RACH configuration index; and whether the spectrum type is paired spectrum or unpaired spectrum.

[0253] In an embodiment, the memory 1430 contains instructions executable by the processor 1420, whereby the terminal device 1400 can further operate to: receive a random access response (RAR) from a network device, the random access response (RAR) including an indication identifying resources in which the terminal device is allowed to send PUSCH data, wherein the network device determines that the RACH preamble is associated with the first random access procedure; and send PUSCH data in the identified resources. That is, the terminal device 1400 uses a four-step random access procedure to access the network device.

[0254] In an embodiment, the memory 1430 contains instructions executable by the processor 1420, whereby the terminal device 1400 may further operate to: if the terminal device 1400 is to send a RACH preamble according to the second random access procedure, then in message A, PUSCH data is sent in a predetermined resource set. That is, the terminal device 1400 uses a two-step random access procedure to access the network device. It should be noted that if the terminal device uses a two-step random access procedure to access the network device, the operation of sending the RACH preamble occurs simultaneously with the operation of sending the PUSCH data in the predetermined resource set.

[0255] In an embodiment, even if a terminal device (e.g., UE) sends a RACH preamble according to a two-step random access procedure, the network device (e.g., gNB) can correctly decode the RACH preamble and knows that the RACH preamble is sent according to the two-step random access procedure, but no PUSCH data is received or the PUSCH data cannot be decoded, and it sends a random access response (RAR) to the terminal device by following the two-step random access procedure. Therefore, after the RACH preamble and PUSCH data are sent according to the second random access procedure or only the RACH preamble is sent according to the second access procedure, the terminal device receives a random access response (RAR) from the network device, wherein the network device determines that the RACH preamble is associated with the second random access procedure, but no PUSCH data is received or correctly decoded. That is, the terminal device 1400 fails to access the network by adopting the two-step random access procedure and then follows the four-step random access procedure to access the network device.

[0256] Since two-step and four-step ROs are time multiplexed and can be separated by tens of milliseconds, a terminal device that is required to use only one of the two-step or four-step ROs needs to wait until the required RO arrives, which is contrary to the low-latency behavior expected in the two-step RACH random access procedure. Therefore, in some embodiments, the terminal device is configured to use both the first and second RO sets, select one of the first and second RO sets to send a RACH preamble in, and then follow the random access procedure associated with the RO in which the RACH preamble is sent. The terminal device determines whether the upcoming time resources are in the first time resource set or the second time resource set, and if the upcoming time resources are in the first time resource set, sends the RACH preamble according to the first random access procedure, and if the upcoming time resources are in the second time resource set, sends the RACH preamble according to the second random access procedure. The terminal device can use a criterion to select the RO, where the criterion can be: sending the RACH preamble in the next available RO after the time at which it determines that a RACH transmission is required.

[0257] The two-step and four-step random access procedures in a cell may be used by different numbers of terminal devices, so it may be desirable to control the load on the resources used by the two-step and four-step random access procedures. One way to achieve this is to restrict terminal devices capable of the two-step random access procedure to use the two-step random access procedure in a first attempt at the random access procedure, and then, if the first attempt is unsuccessful, allow the terminal device to use both the two-step and four-step resources in a second attempt using the four-step random access procedure. In this case, the criteria for RO selection may be: selecting an RO from the second RO set for the first random access attempt, determining that a second random access attempt is required, and then selecting an RO from the first or second RO set for the second random access attempt.

[0258] In some embodiments, the two-step RO is configured separately (e.g., by a network device), and the second time resource indication and the second frequency resource indication are configured by the network device taking into account at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflicts between the second random access procedure and the first random access procedure; and possible conflicts between the second random access procedure and signals other than the RACH preamble.

[0259] For example, when only a small number of terminal devices are expected to use the two-step random access process, a periodicity for the two-step random access process can be configured that is larger than the periodicity for the four-step random access process, and when a large number of terminal devices are expected to use the two-step random access process, a periodicity that is smaller than the periodicity for the four-step random access process can be configured.

[0260] In an embodiment, if the RACH preamble code is sent in a first frequency range (e.g., frequencies below 6 GHz), the time resource is a subframe, or if the RACH preamble code is sent in a second frequency range (e.g., frequencies above 6 GHz), the time resource is a time slot (e.g., a 60 kHz time slot).

[0261] The present disclosure also provides at least one computer program product in the form of a non-volatile or volatile memory, such as a non-transitory computer-readable storage medium, an electrically erasable programmable read-only memory (EEPROM), a flash memory, and a hard disk drive. The computer program product includes a computer program. The computer program includes: code / computer-readable instructions, when it is executed by the processor 1220, causes the network device 1200 to implement, for example, the above-mentioned combination Figure 7 Actions of the process described; or code / computer readable instructions, when executed by the processor 1420, the terminal device 1400 implements, for example, the above combination Fig.10 The actions of the process being described.

[0262] The computer program product may be configured as computer program code arranged in computer program modules. The computer program modules may basically implement Figure 7 or Fig.10 The actions of the process shown in .

[0263] The processor may be a single CPU (central processing unit), but may also include two or more processing units. For example, the processor may include: a general-purpose microprocessor; an instruction set processor and / or an associated chipset and / or a dedicated microprocessor, such as an application-specific integrated circuit (ASIC). The processor may also include a board memory for cache purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may include a non-transitory computer-readable storage medium on which the computer program is stored. For example, the computer program product may be a flash memory, a random access memory (RAM), a read-only memory (ROM) or an EEPROM, and in an alternative embodiment, the above-mentioned computer program modules may be distributed on different computer program products in the form of memory.

[0264] Fig.15 An example of a wireless communication system 1500 is shown in which embodiments of the present disclosure may be implemented. The wireless communication system 1500 may be a cellular communication system, such as a 5G New Radio (NR) network or an LTE cellular communication system. As shown, in this example, the wireless communication system 1500 includes a plurality of radio access nodes 1520 (e.g., an evolved Node B (eNB), a 5G base station referred to as a gNB, or other base stations or similar devices) and a plurality of wireless communication devices 1540. The wireless communication system 1500 is organized into cells 160, which are connected to a core network 1580 via respective radio access nodes 1520. The radio access nodes 1520 are capable of communicating with the wireless communication devices 1540.

[0265] The radio access node 1520 may operate in the manner described with reference to the network device in the embodiments of the present disclosure, and the wireless communication device 1540 may operate in the manner described with reference to the mobile device in the embodiments of the present disclosure.

[0266] For example, the radio access node 1520 sends a random access channel (RACH) timing configuration to the wireless communication device 1540. The RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a first random access procedure; a second time resource indication, which at least identifies a second time resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure; and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send a RACH preamble according to a second random access procedure.

[0267] The wireless communication device 1540 receives the RACH opportunity configuration from the radio access node 1520 and transmits a RACH preamble according to the RACH opportunity configuration.

[0268] In an embodiment, the second time resource set is at least partially different from the first time resource set in the time domain, and / or the second frequency resource set is at least partially different from the first frequency resource set in the frequency domain. That is, the time resources and / or frequency resources used to send the RACH preamble code according to the two-step random access procedure are configured separately from the time resources and / or frequency resources used for the four-step random access procedure.

[0269] In an embodiment, the first time resource indication has the form of a first RACH configuration table, and the second time resource indication has the form of a second RACH configuration table different from the first RACH configuration table. In the example, a set of tables (referred to as table set B) is used for time resource determination for a two-step random access procedure, similar to the three tables defined in TS 38.211 for a four-step random access procedure: Table 6.3.3.2-2, Table 6.3.3.2-3, Table 6.3.3.2-4 (referred to as table set A).

[0270] In an embodiment, the first and second time resource indications are configured such that the second time resource indication identifies a portion of the RACH configuration table and the first time resource indication identifies a different portion of the RACH configuration table. That is, table set A and table set B are identical, but different rows are configured for two-step and four-step random access procedures.

[0271] In an embodiment, table set B may be combined within table set A to form a modified table, and different rows and / or columns in the modified table are configured for two-step and four-step random access procedures, respectively. That is, a new RACH configuration table is preconfigured, and the first and second time resource indications may be configured to identify different columns or different rows in the new RACH configuration.

[0272] For example, table set A (ie, the existing RACH configuration table configured for the four-step random access procedure) is reused for table set B.

[0273] In an embodiment, the second frequency resource indication comprises: a parameter defining the number of RACH opportunities frequency division multiplexed in at least one time resource. For example, the parameter "msgA_preamble-FDM" may be configured in the "RACH-ConfigGeneric information element". In another embodiment, the parameter defining the number of RACH opportunities frequency division multiplexed in at least one time resource is configured by the radio access node 1520 by taking into account at least one of the following parameters: the number of RACH opportunities frequency division multiplexed in at least one time resource for the first random access procedure, the preamble format used for the second random access procedure, the frequency band used for the second random access procedure and the RACH time configuration for the second random access procedure. In yet another embodiment, such a parameter is not present in the second frequency resource indication. The wireless communication device 1540 can determine the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the second random access procedure by considering at least one of the following parameters: the number of RACH opportunities that are frequency-division multiplexed in at least one time resource used for the first random access procedure, the preamble format used for the second random access procedure, the frequency band used for the second random access procedure, and the RACH time configuration used for the second random access procedure.

[0274] In an embodiment, the second frequency resource indication includes: a parameter defining an offset of the lowest RACH opportunity relative to the index of the PRB. In an example, the PRB is the first PRB in the bandwidth portion containing the second frequency resource set, or a PRB in the first frequency resource set. The PRB in the first frequency resource set is a PRB whose index can be the smallest or largest index in the first frequency resource set. Upon receiving the parameter included in the second frequency resource indication, the wireless communication device 1540 can determine the lowest RACH opportunity in the second frequency resource set by at least one of the following ways: adding an offset to the index of the first PRB in the bandwidth portion containing the second frequency resource set, adding an offset to the index of the PRB whose index is the smallest index in the first frequency resource set, and adding an offset to the index of the PRB whose index is the largest index in the first frequency resource set. In another example, there is no such parameter defining the offset of the lowest RACH opportunity relative to the index of the PRB in the second frequency resource indication. The wireless communication device 1540 can determine the lowest RACH opportunity in the second frequency resource set by adding one or more to the index of the PRB whose index is the largest index in the first frequency resource set, as configured by default.

[0275] For example, the parameter "msgA_preamble-FrequencyStart" may be configured in the "RACH-ConfigGeneric information element". As another example, the offset value FrequencyStartOffset may be configured in the "RACH-ConfigGeneric information element". FrequencyStartOffset may be added to the starting frequency msg1-FrequencyStart of the first RO for the four-step random access procedure in one time instance to determine the starting frequency msgA_preamble-FrequencyStart of the first RO for the two-step random access procedure in one time instance, i.e.:

[0276] msgA_preamble-FrequencyStart=msg1-FrequencyStart+FrequencyStartOffset

[0277] The FrequencyStartOffset may be a fixed value or a predetermined value or RRC configured. The entire frequency band used for the RO of the four-step process in one time instance depends on the preamble format and the number of ROs frequency-division multiplexed in one time instance.

[0278] In an embodiment, the radio access node 1520 may determine whether the received RACH preamble is associated with the first random access procedure or the second random access procedure; and in response to determining that the received RACH preamble is associated with the first random access procedure, send a random access response (RAR) to the terminal device. That is, if the wireless communication device 1540 sends the RACH preamble according to the four-step random access procedure, the radio access node 1520 should follow the four-step random access procedure to send the RAR to the terminal device after receiving the RACH preamble. Therefore, the wireless communication device 1540 receives the RAR, which includes an indication of the resources in which the wireless communication device 1540 is allowed to send PUSCH data.

[0279] In an embodiment, the radio access node 1520 may send a random access response (RAR) to the wireless communication device 1540 in response to receiving a RACH preamble without receiving PUSCH data, wherein the RACH preamble is associated with the second random access procedure. That is, even if the wireless communication device 1540 sends a RACH preamble according to the two-step random access procedure, the radio access node 1520 may correctly decode the RACH preamble and know that the RACH preamble is sent according to the two-step random access procedure, but does not receive PUSCH data or cannot decode the PUSCH data, and it sends a random access response (RAR) to the wireless communication device 1540 by following the two-step random access procedure.

[0280] If the wireless communication device 1540 is to send a RACH preamble according to the second random access procedure, it sends PUSCH data in a predetermined resource set in message A. That is, it uses a two-step random access procedure to access the network.

[0281] When the two-step RACH occasions (RO) are configured separately, the second time resource indication and the second frequency resource indication are configured by the radio access node 1520 taking into account at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflict between the second random access procedure and the first random access procedure; and possible conflict between the second random access procedure and other signals other than the RACH preamble code.

[0282] For example, when only a small number of wireless communication devices are expected to use the two-step random access process, a periodicity for the two-step random access process may be configured to be larger than a periodicity for the four-step random access process, and when a large number of wireless communication devices are expected to use the two-step random access process, a periodicity smaller than a periodicity for the four-step random access process may be configured.

[0283] As another example, when the two-step RO partially or completely overlaps with the four-step RO, a predetermined rule may be defined, wherein the rule may be: when the overlap occurs, only the four-step random access procedure is allowed on the four-step RO, and the two-step random access procedure will be blocked. That is, the wireless communication device 1540 determines whether the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set; and in response to determining that the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble according to the two-step random access procedure are within the first time resource set and the first frequency resource set, it sends the RACH preamble in the time-frequency resources according to the four-step random access procedure.

[0284] In an embodiment, the second time resource indication and the second frequency resource indication further indicate an association period, and the association period may be configured by the radio access node 1520 taking into account the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration. For example, only one RO set is used for the two-step random access procedure in a certain association period for mapping SSB to the RACH opportunity of the four-step random access procedure.

[0285] In an embodiment, the second time resource indication and the second frequency resource indication are received via an RRC message.

[0286] The subset may be a fixed subset of the RO from the four-step random access procedure or indicated via RRC signaling. In an embodiment, the radio access node 1520 may configure a subset of time resources or frequency resources by considering the following parameters for the second random access procedure: the number of RACH opportunities mapped by the entire SSB set in one SSB burst set; the number of SSBs actually transmitted; the RACH configuration index; and whether the spectrum type is paired spectrum or unpaired spectrum.

[0287] In an embodiment, even if the wireless communication device 1540 transmits a RACH preamble according to the two-step random access procedure, the radio access node 1520 can correctly decode the RACH preamble, and knowing that the RACH preamble is transmitted according to the two-step random access procedure, but no PUSCH data is received or the PUSCH data cannot be decoded, it transmits a random access response (RAR) to the wireless communication device 1540 by following the two-step random access procedure. Therefore, after the RACH preamble and the PUSCH data are transmitted according to the second random access procedure or only the RACH preamble is transmitted according to the second access procedure, the wireless communication device 1540 receives a random access response (RAR) from the radio access node 1520, wherein the radio access node 1520 determines that the RACH preamble is associated with the second random access procedure, but no PUSCH data is received or correctly decoded. That is, the wireless communication device 1540 fails to access the network by adopting the two-step random access procedure, and then follows the four-step random access procedure to access the network device.

[0288] In some embodiments, the wireless communication device 1540 is configured to use both the first and second RO sets, select one of the first and second RO sets to send a RACH preamble in, and then follow a RACH procedure associated with the RO in which the RACH preamble is sent. The wireless communication device 1540 determines whether the upcoming time resources are in the first time resource set or the second time resource set, and if the upcoming time resources are in the first time resource set, sends the RACH preamble according to the first random access procedure, and if the upcoming time resources are in the second time resource set, sends the RACH preamble according to the second random access procedure. The wireless communication device 1540 can select the RO using a criterion, where the criterion can be: sending the RACH preamble in the next available RO after the time at which it determines that RACH transmission is required.

[0289] The two-step and four-step random access procedures in a cell may be used by different numbers of wireless communication devices, so it may be desirable to control the load on the resources used by the two-step and four-step random access procedures. One way to achieve this is to restrict wireless communication devices capable of the two-step random access procedure to use the two-step random access procedure in a first attempt at the random access procedure, and then, if the first attempt is unsuccessful, allow the wireless communication device to use both the two-step and four-step resources in a second attempt using the four-step random access procedure. In this case, the criteria for RO selection may be: selecting an RO from the second RO set for the first random access attempt, determining that a second random access attempt is required, and then selecting an RO from the first or second RO set for the second random access attempt.

[0290] In some embodiments, the two-step RO is configured separately (e.g., by the radio access node), and the second time resource indication and the second frequency resource indication are configured by the radio access node 1520 taking into account at least one of the following parameters: the periodicity of the second random access procedure relative to the periodicity of the first random access procedure; possible conflict between the second random access procedure and the first random access procedure; and possible conflict between the second random access procedure and other signals other than the RACH preamble.

[0291] For example, when only a small number of wireless communication devices are expected to use the two-step random access process, a periodicity for the two-step random access process may be configured to be larger than a periodicity for the four-step random access process, and when a large number of wireless communication devices are expected to use the two-step random access process, a periodicity smaller than a periodicity for the four-step random access process may be configured.

[0292] refer to Fig.16According to an embodiment, the communication system includes a telecommunication network 1610 (such as a cellular network of the 3GPP type), which includes an access network 1611 (such as a radio access network) and a core network 1614. The access network 1611 includes a plurality of base stations 1612a, 1612b, 1612c, such as NBs, eNBs, gNBs or other types of wireless access points, each of which defines a corresponding coverage area 1613a, 1613b, 1613c. Each base station 1612a, 1612b, 1612c may be connected to the core network 1614 via a wired or wireless connection 1615. A first UE 1691 located in the coverage area 1613c is configured to be wirelessly connected to the corresponding base station 1612c or to be paged by the corresponding base station 1612c. A second UE 1692 in the coverage area 1613a may be wirelessly connected to the corresponding base station 1612a. Although multiple UEs 1691 , 1692 are shown in this example, the disclosed embodiments are equally applicable to situations where only a UE is in the coverage area or only a UE is connected to the corresponding base station 1612 .

[0293] The telecommunications network 1610 itself is connected to a host computer 1630, which may be embodied in the hardware and / or software of a standalone server, a cloud-implemented server, a distributed server, or as a processing resource in a server farm. The host computer 1630 may be under the ownership or control of a service provider, or may be operated by or on behalf of a service provider. The connections 1621 and 1622 between the telecommunications network 1610 and the host computer 1630 may extend directly from the core network 1614 to the host computer 1630, or may pass through an optional intermediate network 1620. The intermediate network 1620 may be one of a public network, a private network, or a managed network, or a combination of more than one of them; the intermediate network 1620 (if any) may be a backbone network or the Internet; in particular, the intermediate network 1620 may include two or more sub-networks (not shown).

[0294] Fig.16The communication system generally implements a connection between the connected UE 1691, 1692 and the host computer 1630. The connection can be described as an over-the-top (OTT) connection 1650. The host computer 1630 and the connected UE 1691, 1692 are configured to use the access network 1611, the core network 1614, any intermediate network 1620 and possible other infrastructure (not shown) as intermediaries to transmit data and / or signaling via the OTT connection 1650. The OTT connection 1650 can be transparent in the sense that the participating communication devices through which the OTT connection 1650 passes do not know the route of the uplink and downlink communication. For example, the base station 1612 may not be informed or need not be informed of the past route of the incoming downlink communication with data from the host computer 1630 to be forwarded (e.g., switched) to the connected UE 1691. Similarly, base station 1612 need not be aware of future routing of outgoing uplink communications originating from UE 1691 toward host computer 1630 .

[0295] Now refer to Fig.17 Describe the example implementation of the UE, base station and host computer discussed in the previous paragraph according to the embodiment. In the communication system 1700, the host computer 1710 includes hardware 1715, the hardware 1715 includes a communication interface 1716, and the communication interface 1716 is configured to establish and maintain a wired or wireless connection with the interface of different communication devices of the communication system 1700. The host computer 1710 also includes: a processing circuit 1718, which may have storage and / or processing capabilities. In particular, the processing circuit 1718 may include one or more programmable processors, application specific integrated circuits, field programmable gate arrays, or a combination of these components (not shown) suitable for executing instructions. The host computer 1710 also includes software 1711, which is stored in the host computer 1710 or can be accessed by the host computer 1710 and can be executed by the processing circuit 1718. Software 1711 includes a host application 1712. The host application 1712 is operable to provide services to a remote user, such as a UE 1730 connected via an OTT connection 1750 terminating at the UE 1730 and the host computer 1710. In providing services to the remote user, the host application 1712 may provide user data transmitted using the OTT connection 1750.

[0296] The communication system 1700 also includes a base station 1720 provided in the telecommunication system, and the base station 1720 includes hardware 1725 that enables it to communicate with the host computer 1710 and the UE 1730. The hardware 1725 may include a communication interface 1726 for establishing and maintaining a wired or wireless connection with different communication devices of the communication system 1700, and a communication interface 1726 for establishing and maintaining a connection with a network located in the coverage area ( Fig.17 1727 of at least a wireless connection 1770 of a UE 1730 in the embodiment of the present invention (not shown). The communication interface 1726 may be configured to facilitate a connection 1760 to a host computer 1710. The connection 1760 may be direct, or it may pass through a core network ( Fig.17 1720) and / or traverse one or more intermediate networks external to the telecommunications system. In the illustrated embodiment, the hardware 1725 of the base station 1720 also includes processing circuitry 1728, which may include one or more programmable processors, application specific integrated circuits, field programmable gate arrays, or a combination of these components (not shown) suitable for executing instructions. The base station 1720 also has software 1721 stored internally or accessible via an external connection.

[0297] The communication system 1700 also includes the UE 1730 already cited. Its hardware 1735 may include a radio interface 1737, which is configured to establish and maintain a wireless connection 1770 with a base station serving the coverage area where the UE 1730 is currently located. The hardware 1735 of the UE 1730 also includes a processing circuit 1738, which may include one or more programmable processors, application specific integrated circuits, field programmable gate arrays, or a combination of these components (not shown) suitable for executing instructions. The UE 1730 also includes software 1731, which is stored in the UE 1730 or can be accessed by the UE 1730 and can be executed by the processing circuit 1738. The software 1731 includes a client application 1732. The client application 1732 is operable to provide services to human users or non-human users via the UE 1730 under the support of the host computer 1710. In the host computer 1710, the executing host application 1712 can communicate with the executing client application 1732 via an OTT connection 1750 that terminates at the UE 1730 and the host computer 1710. When providing services to users, the client application 1732 can receive request data from the host application 1712 and provide user data in response to the request data. The OTT connection 1750 can transmit both the request data and the user data. The client application 1732 can interact with the user to generate the user data it provides.

[0298] It should be noted that Fig.17 The host computer 1710, base station 1720 and UE 1730 shown in FIG. 1 can be respectively connected to Fig.16 The host computer 1630, one of the base stations 1612a, 1612b, 1612c, and one of the UEs 1691, 1692 may be similar or identical. That is, the internal workings of these entities may be similar to Fig.17 As shown, and independently, the surrounding network topology can be Fig.16network topology.

[0299] exist Fig.17 In FIG. 1 , an OTT connection 1750 has been abstractly drawn to illustrate communication between a host computer 1710 and a UE 1730 via a base station 1720, without explicitly involving any intermediate devices and the precise routing of messages via these devices. The network infrastructure may determine the routing, which may be configured to hide the routing from the UE 1730 or the service provider operating the host computer 1710, or both. When the OTT connection 1750 is active, the network infrastructure may further make decisions to dynamically change the routing (e.g., based on load balancing considerations or reconfiguration of the network).

[0300] The wireless connection 1770 between the UE 1730 and the base station 1720 is in accordance with the teachings of the embodiments described throughout the present disclosure. One or more of the various embodiments improve the performance of the OTT service provided to the UE 1730 using the OTT connection 1750, wherein the wireless connection 1770 forms the last segment. More specifically, the teachings of these embodiments can improve radio resource utilization and thereby provide benefits such as reduced user waiting time.

[0301] A measurement process may be provided to monitor data rates, latency, and other factors improved by one or more embodiments. In response to changes in the measurement results, there may also be an optional network function for reconfiguring the OTT connection 1750 between the host computer 1710 and the UE 1730. The measurement process and / or network function for reconfiguring the OTT connection 1750 may be implemented in the software 1711 and hardware 1715 of the host computer 1710, or in the software 1731 and hardware 1735 of the UE 1730, or in both. In an embodiment, a sensor (not shown) may be deployed in or associated with a communication device through which the OTT connection 1750 passes; the sensor may participate in the measurement process by providing the values ​​of the monitoring quantities exemplified above, or by providing the values ​​of other physical quantities from which the software 1711, 1731 can calculate or estimate the monitoring quantities. The reconfiguration of the OTT connection 1750 may include message formats, retransmission settings, preferred routes, etc.; the reconfiguration does not need to affect the base station 1720, and the base station 1720 may not know or be aware of the reconfiguration. These processes and functions may be known and practiced in the art. In certain embodiments, the measurements may involve proprietary UE signaling that facilitates host computer 1710 to measure throughput, propagation time, latency, etc. The measurements may be implemented in the following manner: Software 1711 and 1731 use OTT connection 1750 to cause messages (particularly empty messages or "dummy" messages) to be transmitted while it monitors propagation time, errors, etc.

[0302] Fig.18 1 is a flow chart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station and a UE, which can be reference Fig.16 and Fig.17 To simplify this disclosure, only the Fig.18 . In step 1810, the host computer provides user data. In sub-step 1811 of step 1810 (which may be optional), the host computer provides the user data by executing a host application. In step 1820, the host computer initiates a transmission carrying the user data to the UE. In step 1830 (which may be optional), in accordance with the teachings of the embodiments described throughout the present disclosure, the base station transmits the user data carried in the transmission initiated by the host computer to the UE. In step 1840 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.

[0303] Fig.19 1 is a flow chart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station and a UE, which can be reference Fig.16 and Fig.17 To simplify this disclosure, only the Fig.19 . In step 1910 of the method, the host computer provides user data. In an optional sub-step (not shown), the host computer provides the user data by executing a host application. In step 1920, the host computer initiates a transmission carrying the user data to the UE. According to the teachings of the embodiments described throughout the present disclosure, the transmission may pass through a base station. In step 1930 (which may be optional), the UE receives the user data carried in the transmission.

[0304] Fig. 20 1 is a flow chart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station and a UE, which can be reference Fig.16 and Fig.17 To simplify this disclosure, only the Fig. 20. In step 2010 (which may be optional), the UE receives input data provided by the host computer. Additionally or optionally, in step 2020, the UE provides user data. In sub-step 2021 (which may be optional) of step 2020, the UE provides user data by executing a client application. In sub-step 2011 (which may be optional) of step 2010, the UE executes a client application, which provides user data in response to the received input data provided by the host computer. When providing user data, the executed client application may also consider user input received from the user. Regardless of the specific manner of providing user data, the UE initiates transmission of user data to the host computer in sub-step 2030 (which may be optional). In step 2040 of the method, according to the teachings of the embodiments described throughout the present disclosure, the host computer receives user data transmitted from the UE.

[0305] Fig.21 1 is a flow chart showing a method implemented in a communication system according to an embodiment. The communication system includes a host computer, a base station and a UE, which can be reference Fig.16 and Fig.17 To simplify this disclosure, only the Fig.21 In step 2110 (which may be optional), according to the teachings of the embodiments described throughout the present disclosure, the base station receives user data from the UE. In step 2120 (which may be optional), the base station initiates a transmission of the received user data to the host computer. In step 2130 (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station.

[0306] The present disclosure has been described above with reference to the embodiments of the present disclosure. It should be understood that those skilled in the art can make various modifications, substitutions and additions without departing from the spirit and scope of the present disclosure. Therefore, the scope of the present disclosure is not limited to the above-mentioned specific embodiments, but is only limited by the attached claims.

Claims

1. A method (700) in a network device (1100, 1200), comprising: Sending (S710) a random access channel RACH timing configuration to a terminal device (1300, 1400), wherein the RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble code according to a first random access procedure, a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send the RACH preamble code according to the first random access procedure, wherein the first random access procedure is a four-step random access procedure, a second time resource indication, which identifies at least a second time resource set in which the terminal device is allowed to send a RACH preamble according to a second random access procedure, and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send the RACH preamble code according to the second random access procedure; and A RACH preamble code sent from the terminal device according to the RACH timing configuration is received (S720).

2. The method according to claim 1, wherein: The second set of time resources is at least partially different from the first set of time resources in the time domain, and / or the second set of frequency resources is at least partially different from the first set of frequency resources in the frequency domain.

3. The method according to claim 1, wherein: The first time resource indication and the second time resource indication are configured such that the second time resource indication identifies a portion in a RACH configuration table and the first time resource indication identifies a different portion in the RACH configuration table.

4. The method according to claim 3, wherein: The portion includes rows and / or columns in the RACH configuration table.

5. The method according to claim 4, wherein: The existing RACH configuration table configured for the first random access procedure is reused or modified as the RACH configuration table.

6. The method according to claim 1, wherein: The first time resource indication is in the form of a first RACH configuration table, and the second time resource indication is in the form of a second RACH configuration table different from the first RACH configuration table.

7. The method according to claim 1, wherein: The second frequency resource indication includes: a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource, and / or a parameter defining an offset of a lowest RACH opportunity relative to an index of a physical resource block PRB.

8. The method according to claim 7, wherein: The PRB is the first PRB in the bandwidth part containing the second frequency resource set, or is a PRB in the first frequency resource set.

9. The method according to claim 8, wherein: The PRB in the first frequency resource set is a PRB whose index is the minimum or maximum index in the first frequency resource set.

10. The method according to claim 7, wherein: The parameter defining the number of RACH opportunities frequency division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities frequency division multiplexed in the at least one time resource for the first random access procedure, a preamble format for the second random access procedure, a frequency band for the second random access procedure, and a RACH time configuration for the second random access procedure.

11. The method according to claim 1, further comprising: It is determined (S730) whether the received RACH preamble is associated with the first random access procedure or the second random access procedure.

12. The method according to claim 11, further comprising: In response to determining that the received RACH preamble is associated with the first random access procedure, a random access response RAR is sent (S740) to the terminal device.

13. The method according to claim 1, further comprising: In response to receiving the RACH preamble but not receiving the PUSCH data, sending (S750) a random access response RAR to the terminal device, The RACH preamble code is associated with the second random access process.

14. The method according to claim 1, wherein: The second time resource indication and the second frequency resource indication are configured by considering at least one of the following parameters: a periodicity of the second random access procedure relative to a periodicity of the first random access procedure; a possible conflict between the second random access procedure and the first random access procedure; as well as Possible collision between the second random access procedure and other signals besides the RACH preamble.

15. The method according to claim 1, wherein: The second time resource indication and the second frequency resource indication indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

16. The method according to claim 15, wherein: The second time resource indication and the second frequency resource indication further indicate an associated period.

17. The method according to claim 16, wherein: The association period is configured by considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration.

18. The method according to claim 1, wherein: The second time resource indication and the second frequency resource indication are sent via an RRC message.

19. The method according to claim 15, wherein: The subset of time resources or frequency resources is configured by considering the following parameters for the second random access procedure: The number of RACH opportunities mapped by the entire set of synchronization signal SS / physical broadcast channel PBCH blocks SSB in one SSB burst set; The number of SSBs actually sent; RACH configuration index; as well as The spectrum type is paired or unpaired.

20. The method according to any one of claims 1 to 19, wherein: The time resource is a subframe if the RACH preamble is transmitted in a first frequency range, or a time slot if the RACH preamble is transmitted in a second frequency range.

21. The method according to any one of claims 1 to 19, wherein: The second random access procedure is a two-step random access procedure, wherein in the two-step random access procedure, the terminal device sends a message A including a RACH preamble code and PUSCH data.

22. A network device (1200) comprising a transceiver (1210), a processor (1220) and a memory (1230), wherein the memory (1230) comprises instructions executable by the processor (1220), whereby the network device (1200) is operable to implement the method according to any one of claims 1-21.

23. A computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor in a network device, cause the network device to implement the method according to any one of claims 1 to 21.

24. A method (1000) in a terminal device (1300, 1400), comprising: A random access channel RACH timing configuration is received (S1010) from a network device, where the RACH timing configuration includes: a first time resource indication, which at least identifies a first time resource set, in which the terminal device is allowed to send a RACH preamble code according to a first random access procedure, a first frequency resource indication, which at least identifies a first frequency resource set, in which the terminal device is allowed to send the RACH preamble code according to the first random access procedure, wherein the first random access procedure is a four-step random access procedure, a second time resource indication, which identifies at least a second time resource set in which the terminal device is allowed to send a RACH preamble according to a second random access procedure, and a second frequency resource indication, which at least identifies a second frequency resource set, in which the terminal device is allowed to send the RACH preamble code according to the second random access procedure; and A RACH preamble is sent (S1020) according to the RACH timing configuration.

25. The method according to claim 24, wherein: The second set of time resources is at least partially different from the first set of time resources in the time domain, and / or the second set of frequency resources is at least partially different from the first set of frequency resources in the frequency domain.

26. The method according to claim 25, wherein: The first time resource indication and the second time resource indication are configured such that the second time resource indication identifies a portion in a RACH configuration table and the first time resource indication identifies a different portion in the RACH configuration table.

27. The method according to claim 26, wherein: The portion includes rows and / or columns in the RACH configuration table.

28. The method according to claim 27, wherein: The existing RACH configuration table configured for the first random access procedure is reused or modified as the RACH configuration table.

29. The method of claim 24, wherein: Sending (S1020) a RACH preamble according to the RACH opportunity configuration includes: The lowest RACH opportunity in the second frequency resource set is determined by adding one or more to the index of the PRB whose index is the largest index in the first frequency resource set.

30. The method of claim 24, wherein: The second frequency resource indication includes: a parameter defining an offset of a minimum RACH opportunity relative to a PRB, and sending a RACH preamble according to the RACH opportunity configuration includes: The lowest RACH opportunity in the second frequency resource set is determined by at least one of the following: in case the PRB is the first PRB in the bandwidth part containing the second set of frequency resources, adding the offset to the index of the first PRB in the bandwidth part containing the second set of frequency resources, adding the offset to the index of the PRB whose index is the smallest index in the first frequency resource set, and The offset is added to the index of the PRB whose index is the largest index in the first frequency resource set.

31. The method of claim 24, wherein: The second frequency resource indication includes: a parameter defining the number of RACH opportunities frequency-division multiplexed in at least one time resource.

32. The method according to claim 31, wherein: The parameter defining the number of RACH opportunities frequency division multiplexed in at least one time resource is configured by considering at least one of the following parameters: the number of RACH opportunities frequency division multiplexed in at least one time resource for the first random access procedure, a preamble format for the second random access procedure, a frequency band for the second random access procedure, and a RACH time configuration for the second random access procedure.

33. The method of claim 24, wherein: The second time resource indication and the second frequency resource indication indicate that the second time resource set is a subset of the first time resource set in the time domain, and the second frequency resource set is a subset of the first frequency resource set in the frequency domain.

34. The method of claim 33, further comprising: In response to determining (S1030) that the time-frequency resources within the second time resource set and the second frequency resource set to be used for sending the RACH preamble code according to the second random access procedure are within the first time resource set and the first frequency resource set, a RACH preamble code is sent (S1020) in the time-frequency resources according to the first random access procedure.

35. The method of claim 33, wherein: The second time resource indication and the second frequency resource indication further indicate an associated period.

36. The method of claim 35, wherein: The association period is configured by considering the following parameters for the second random access procedure: preamble format, RACH configuration period, association period configuration, and association mode period configuration.

37. The method of claim 24, wherein: The second time resource indication and the second frequency resource indication are received via an RRC message.

38. The method of claim 33, wherein: The subset of time resources or frequency resources is configured by considering the following parameters for the second random access procedure: The number of RACH opportunities mapped by the entire set of synchronization signal SS / physical broadcast channel PBCH blocks SSB in one SSB burst set; The number of SSBs actually sent; RACH configuration index; as well as The spectrum type is paired or unpaired.

39. The method of claim 24, further comprising: receiving (S1040) a random access response RAR from the network device, the RAR comprising an indication identifying resources in which the terminal device is allowed to send PUSCH data, wherein the network device determines that the RACH preamble is associated with the first random access procedure; and The PUSCH data is sent (S1050) in the identified resources.

40. The method of claim 24, wherein: If the RACH preamble is to be sent according to the second random access procedure, the method further includes: In message A, PUSCH data is sent in a predetermined resource set.

41. The method of claim 24, further comprising: determining whether an upcoming time resource is in the first time resource set or in the second time resource set; as well as If the upcoming time resource is in the first time resource set, a RACH preamble is sent according to the first random access procedure, and if the upcoming time resource is in the second time resource set, a RACH preamble is sent according to the second random access procedure.

42. The method of claim 24, further comprising: After a RACH preamble and PUSCH data are sent according to the second random access procedure, or after only a RACH preamble is sent according to the second random access procedure, a random access response RAR is received from the network device, wherein the network device determines that the RACH preamble is associated with the second random access procedure, but no PUSCH data is received or correctly decoded.

43. The method of claim 24, wherein: The second time resource indication and the second frequency resource indication are configured by considering at least one of the following parameters: a periodicity of the second random access procedure relative to a periodicity of the first random access procedure; a possible conflict between the second random access procedure and the first random access procedure; as well as Possible collision between the second random access procedure and other signals besides the RACH preamble.

44. The method according to any one of claims 24 to 43, wherein: The time resource is a subframe if the RACH preamble is transmitted in a first frequency range, or a time slot if the RACH preamble is transmitted in a second frequency range.

45. The method according to any one of claims 24 to 43, wherein: The second random access procedure is a two-step random access procedure, wherein in the two-step random access procedure, the terminal device sends a message A including a RACH preamble code and PUSCH data.

46. ​​A terminal device (1400) comprising a transceiver (1410), a processor (1420) and a memory (1430), wherein the memory (1430) comprises instructions executable by the processor (1420), whereby the terminal device (1400) is operable to implement a method according to any one of claims 24-45.

47. A computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor in a terminal device, cause the terminal device to implement the method according to any one of claims 24-45.

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