Systems and methods for random access channel resource determination

Abstract

Systems and methods for wireless communication are disclosed herein. In some embodiments, a method of wireless communication includes indicating, by a base station, at least one set of resources for network access to a wireless communication device; and performing, by the base station, a network access procedure with the wireless communication device based on the indicated at least one set of resources for network access.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of telecommunications, and in particular, to random access channel occasion determination for non-terrestrial networks. BACKGROUND

[0002] To expand the utilization and coverage of wireless access technologies such as, but not limited to, long term evolution (LTE) technologies and new radio (NR) technologies, connectivity provided by satellites and airborne vehicles has been considered as a promising application. A network that incorporates satellites and / or airborne vehicles to perform the functions (all or part of the functions) of a ground base station (BS) is referred to as a non-terrestrial network (NTN). Satellites and airborne vehicles are collectively referred to as non-terrestrial BSs. Examples of satellites include, but are not limited to, low earth orbit (LEO) satellites, etc. Examples of airborne vehicles include, but are not limited to, high altitude platform stations (HAPS), balloons, unmanned aerial vehicles (UAVs), other suitable airborne vehicles, etc. SUMMARY

[0003] The exemplary embodiments disclosed herein are intended to address one or more of the problems in the art that have been presented with existing technologies, and to provide additional functionality that will become apparent to those of ordinary skill in the art having the benefit of the following detailed description when taken in conjunction with the accompanying drawings. In accordance with various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. It should be understood, however, that these embodiments are presented by way of example and not limitation, and that modifications can be made by those of ordinary skill in the art having the benefit of the present disclosure, and that such modifications are intended to be within the scope of the present disclosure.

[0004] In some arrangements, a BS indicates to a UE at least one set of resources for network access, and performs a network access procedure with the UE based on the indicated at least one set of resources for network access.

[0005] In some arrangements, a UE receives an indication of at least one set of resources for network access from a BS, selects a resource set based on measurements performed by the UE, and performs a network access procedure with the BS based on the selected resource set.

[0006] The above and other aspects and implementations thereof are described in greater detail in the attached drawings, the description and the claims. BRIEF DESCRIPTION OF DRAWINGS

[0007] Various exemplary embodiments of the present solution will be described in detail below with reference to the following drawings. The drawings provided are for illustrative purposes only and depict only exemplary embodiments of the present solution to facilitate the reader's understanding. The drawings should therefore not be considered limiting of the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, these drawings are not necessarily made to scale.

[0008] FIG. 1A FIG. 1 is a diagram illustrating a beam of a cell of a BS in a wireless communication system according to various arrangements.

[0009] FIG. 1B FIG. 1 is a diagram illustrating a beam of a cell of a BS in a wireless communication system according to various arrangements.

[0010] FIG. 2 FIG. 2 is a diagram illustrating an exemplary non-terrestrial network cell with a circular beam according to various arrangements.

[0011] FIG. 3 FIG. 3 is a diagram illustrating an exemplary non-terrestrial network cell with 4 strip beams according to various arrangements.

[0012] FIG. 4 FIG. 4 is a diagram illustrating an example of a mapping between ROs and sub-areas according to various arrangements.

[0013] FIG. 5 FIG. 5 is a diagram illustrating an example of a mapping between random access channel occasions and sub-areas according to various arrangements.

[0014] FIG. 6 FIG. 5 is a diagram illustrating an example of a mapping between random access channel occasions and sub-areas according to various arrangements.

[0015] FIG. 7 FIG. 6 is a flow diagram illustrating an exemplary method for determining a random access channel type according to various arrangements.

[0016] FIG. 8 FIG. 7 is a diagram illustrating an exemplary timeline for falling back to a 4-step random access channel (RACH) according to various arrangements.

[0017] FIG. 9 FIG. 8 is a flow diagram illustrating an exemplary method for determining and applying a timing advance according to various arrangements.

[0018] FIG. 10 FIG. 8 is a flow diagram illustrating an exemplary method for determining and applying a timing advance according to various arrangements.

[0019] FIG. 11Ais a flowchart illustrating an example method for wireless communication that supports determining resources for network access in accordance with various aspects described herein.

[0020] FIG. 11B is a flowchart illustrating an example method for wireless communication that supports determining resources for network access in accordance with various aspects described herein.

[0021] FIG. 12A is a block diagram illustrating an example base station in accordance with various aspects described herein.

[0022] FIG. 12B is a block diagram illustrating an example user equipment in accordance with various aspects described herein. DETAILED DESCRIPTION

[0023] Various example embodiments of the present solution are described hereinbelow with reference to the accompanying drawings to enable a person of ordinary skill in the art to make and use the present solution. As will be apparent to those of ordinary skill in the art, various changes or modifications can be made to the examples described herein without departing from the scope of the present solution. Accordingly, the present disclosure is not limited to the example embodiments and applications described and illustrated herein. In addition, the particular order or hierarchy of steps in the methods disclosed herein are merely examples. The particular order or hierarchy of steps in the methods disclosed herein can be re-arranged based on design, depending on the implementation, while still falling within the scope of the present solution. As such, those of ordinary skill in the art will appreciate that the methods and techniques disclosed herein present various steps or acts in a sample order, and the present solution is not limited to the specific order or hierarchy presented unless explicitly stated otherwise.

[0024] In non-terrestrial networks (NTNs), coverage by satellites or aerial vehicles is typically achieved using multiple beams. For example, as a satellite moves along its orbit, the beams of the satellite can sweep across a coverage area. As the satellite moves, user equipments (UEs) that are fixed or relatively fixed on the ground are served by different beams of the satellite over time. The coverage area of a satellite can be large, e.g., a beam coverage area of a single satellite is on the order of hundreds of kilometers in diameter. The number of UEs within the coverage of a satellite is likewise expected to be large, and the UEs can have very different elevation angles, which results in different propagation delays and Doppler shifts. As such, efficiently supporting random access from multiple UEs in an NTN is a challenging topic.

[0025] To reduce the signaling overhead and random access delay due to long propagation distance, 2-step RACH is a good candidate in NTN scenarios with only one round of interaction between a base station (BS) and a UE. In 2-step RACH, the contention-based random access procedure involves only 2 steps. A first message (e.g., MSG_A) containing a preamble and a payload is transmitted from the UE to the BS. Then, a second message (e.g., MSG_B) containing a response and other content is transmitted from the BS to the UE. Because the payload is transmitted in the first message together with the preamble, time and frequency synchronization among the UEs that are present at the same time is important to ensure satisfactory performance. The difference between 2-step RACH and 4-step RACH is that in 2-step RACH the data payload resources (for MSG_A transmission) are associated with RO resources.

[0026] In NTN, different beam schemes can be supported depending on different requirements. FIG. 1A is an illustration showing beams of a cell 100 of a BS in a wireless communication system according to various arrangements. Referring to FIG. 1A , the BS can be a non-terrestrial BS, such as but not limited to a satellite or an airborne vehicle. FIG. 1A The BS shown in the example of may provide circular beams 110, 111, 112, 113, 114, 115, and 116. Each beam 110-116 forms a coverage area. When a UE is within the coverage area of one of the beams 110-116, the UE can transmit and receive data to and from the BS via this beam. The beams 110-116 (and their coverage areas) collectively form the cell 100.

[0027] FIG. 1B is an illustration showing beams of a cell of a BS in a wireless communication system according to various arrangements. Referring to FIG. 1B , the BS can be a non-terrestrial BS, such as but not limited to a satellite or an airborne vehicle. FIG. 1B The BS shown in the example of may provide strip beams 160, 161, 162, and 163. Each beam 160-163 forms a coverage area. When a UE is within the coverage area of one of the beams 160-163, the UE can transmit and receive data to and from the BS via this beam. The beams 160-163 (and their coverage areas) collectively form the cell 150.

[0028] As FIG. 1A and FIG. 1BAs shown, the BS can broadcast at least a circular beam and a strip beam. The time and frequency offsets of different UEs can be very different in different areas of a given beam coverage. For example, zero Doppler shift is experienced at the center (or nadir) of the circular beam, but the Doppler shift at the edge of the circular beam can be several kHz depending on the beam size. In another example of the strip beam, the time offset due to the difference in propagation delay experienced at the center (or nadir) and at the edge of the beam can be larger than the Physical Random Access Channel (PRACH) preamble cyclic prefix (CP). These physical impairments can cause problems in PRACH performance in NTN scenarios. Accordingly, the arrangements disclosed herein aim to enhance PRACH in NTN.

[0029] Time / frequency synchronization between coexisting UEs is a key point to guarantee satisfactory PRACH performance, especially for 2-step RACH with payload in MSG_A. In one embodiment, to reduce time / frequency asynchronies between coexisting UEs, it is beneficial to divide the coverage of a beam into sub-areas. UEs in the same sub-area share the same RACH occasion (RO).

[0030] FIG. 2 is a diagram illustrating an exemplary NTN cell with a circular beam 240 having a nadir 250 as a reference point, according to various arrangements. In this exemplary NTN, the time offset due to the difference in propagation delay experienced at the nadir and at the edge of the beam can be larger than the legacy PRACH preamble CP length, and for a low earth orbit (LEO) bearing BS 210, the frequency offset due to the Doppler shift of the moving BS 210 varies significantly from the nadir 250 to the edge of the beam. As shown, the coverage area of the beam 240 can be divided into a first sub-area 220 and a second sub-area 230. UEs in the same sub-area share similar propagation delays. Therefore, UEs in the same sub-area should use the same RO resource, while UEs in different sub-areas should use different RO resources. FIG. 2

[0031] FIG. 3 is a diagram illustrating an exemplary NTN cell with 4 strip SSB beams 340 from a LEO bearing BS 310, having a symmetric center 350 of the beams 340 as a reference point, according to various arrangements. In this exemplary NTN, the time offset due to the difference in propagation delay experienced at the symmetric center 350 and at the edge of the beam can be larger than the legacy PRACH preamble CP length. As shown, the coverage area of the beams 340 can be divided into a first sub-area 320 and a second sub-area 330. UEs in the same sub-area share similar propagation delays. Therefore, UEs in the same sub-area should use the same RO resource, while UEs in different sub-areas should use different RO resources. FIG. 3 ​As shown, the coverage area of one beam can be divided into a first sub-area 320 and a second sub-area 330. UEs in the same sub-area share similar propagation delays. Therefore, UEs in the same sub-area should use the same RO resource, while UEs in different sub-areas should use different RO resources.

[0032] In some embodiments, the BS indicates one or more sets of resources (e.g., ROs) for network access. The BS then performs a network access procedure (e.g., RACH procedure) with the UE based on the indicated set of resources. The set of resources for network access can be a PRACH occasion, a PRACH preamble index, or a PUSCH occasion for MSG_A in 2-step RACH. In some embodiments, each of the one or more sets of resources for network access is associated with at least one of a cell, a beam, a sub-area of the beam, a UE type, a capability of the UE, or a frequency portion of the cell. In other embodiments, the UE receives an indication of one or more sets of resources (e.g., ROs) for network access, performs measurements, determines the appropriate set of resources, and performs a network access procedure (e.g., RACH procedure) with the BS according to the RO. This approach is applicable to both 2-step RACH and 4-step RACH. In some embodiments, the coverage range partitioning for sub-areas is based on location, while in other embodiments, the coverage range partitioning for sub-areas is based on time. In other embodiments, the coverage range partitioning for sub-areas is based on frequency offset.

[0033] In a first embodiment for location-based coverage range partitioning, the BS indicates a reference point location of a beam. For example, the reference point can be the lowest (or center) point of the beam, the closest point in the beam to the BS in the air relative to a predetermined reference height (e.g., sea level), or the center point of a symmetric beam. The BS then indicates a distance threshold that partitions the beam coverage range into sub-areas. UEs in sub-area 1 will have a distance from the UE to the reference point that is less than the distance threshold, while UEs in sub-area 2 will have a distance from the UE to the reference point that is greater than or equal to (i.e., not less than) the distance threshold. The BS can indicate more than one distance threshold in order to partition the beam coverage range into more than two sub-areas.

[0034] For location-based coverage range partitioning, the measurement performed by the UE includes the distance of the UE from the reference point. The UE then determines the appropriate set of resources based on the measurement and comparison to the threshold, selecting a first resource corresponding to sub-area 1 if the measurement value is less than the distance threshold, and a second resource corresponding to sub-area 2 if the measurement value is greater than or equal to (i.e., not less than) the distance threshold. In some embodiments, the first and second ROs are different. In other embodiments, the first and second ROs are the same but have different preambles.

[0035] In a second embodiment for location-based coverage partitioning, the BS indicates the association between ROs and sub-areas by allocating ROs equally among sub-areas, which is more efficient than unequally dividing ROs and saves signaling. FIG. 4 is a diagram showing an example of mapping between ROs and sub-areas according to the second embodiment. The diagram takes time domain as the x-axis and frequency domain as the y-axis. As shown, if prach_FDM = 2, which means 2 PRACH resources are configured in the frequency domain, and ssb_per_RO = 1 / 2, which means 1 synchronization signal block (SSB) is mapped to 2 consecutive ROs, then 2 ROs are available for 2 sub-areas accordingly. The first RO 410 corresponds to the first sub-area, which can be the first sub-area 220 or 320 from FIG. 4 , and the second RO 420 corresponds to the second sub-area, which can be the second sub-area 230 or 330 from FIG. 2 to FIG. 3 . The first RO 410 and the second RO 420 share the time domain but have different frequency domains. The association between ROs and thresholds can be given by the following formula: FIG. 2 to FIG. 3

[0036]

[0037] where d is the distance between the location of the UE and the location of the reference point. Generally, if N 子区域 sub-areas are obtained with a given threshold(s), all available ROs are allocated equally among the N 子区域 sub-areas.

[0038] The sub-area index is mapped to ROs in a specific order. First, within a single RO, the sub-area index is mapped in ascending order of preamble index. For example, in one RO, the first sub-area is mapped with the first 10 preambles, the second sub-area is mapped with the next 10 preambles, and so on. Second, the sub-area index is mapped in ascending order of frequency resource index of frequency division multiplexing (FDM) ROs. If the first method is not sufficient, the second method is used. Third, the sub-area index is mapped in ascending order of time resource index of time division multiplexing (TDM) ROs within a PRACH slot. Fourth, the sub-area index is mapped in ascending order of index of PRACH slots.

[0039] In a third embodiment for location-based coverage partitioning, the BS indicates the association between ROs and sub-areas by specifying ROs for each sub-area (which can not result in ROs being allocated equally, as in the second embodiment). FIG. 5 is a diagram showing an example of mapping between ROs and sub-areas according to the third embodiment. The diagram takes time domain as the x-axis and frequency domain as the y-axis. As shown, if prach_FDM = 2, which means 2 PRACH resources are configured in the frequency domain, and ssb_per_RO = 1 / 2, which means 1 synchronization signal block (SSB) is mapped to 2 consecutive ROs, then 2 ROs are available for 2 sub-areas accordingly. The first RO 410 corresponds to the first sub-area, which can be the first sub-area 220 or 320 from FIG. 5 ​If prach_FDM = 4, it means 4 PRACH resources are configured in frequency domain (given by the first RO 530, the second RO 540, the third RO 550, and the fourth RO 560), and ssb_per_RO = 1, it means 1 SSB is mapped to 1 RO, then only 1 RO can be used for 2 sub-areas in SSB1 accordingly. Thus, in FIG. 5 the first sub-area 510 and the second sub-area 520 are associated with a single RO (here, the first RO 530). The association between the RO and the threshold is controlled by the following equation:

[0040]

[0041] where d is the distance between the UE location and the reference point location, and where M i preambles are used for each sub-area i. The sub-area index is then mapped to the RO according to a specific order. First, within a single RO, the sub-area index is mapped in ascending order of preamble index. For example, in one RO, the first sub-area is mapped with the first 10 preambles, the second sub-area is mapped with the next 10 preambles, and so on. Second, the sub-area index is mapped in ascending order of frequency resource index of frequency division multiplexing (FDM) ROs. If the first method is not sufficient, the second method is used. Third, the sub-area index is mapped in ascending order of time resource index of time division multiplexing (TDM) ROs within a PRACH slot. Fourth, the sub-area index is mapped in ascending order of index of PRACH slots.

[0042] In a fourth embodiment for location-based coverage segmentation, for a global navigation satellite system (GNSS)-enabled UE (e.g., the UE in the first to third embodiments) or for a fixed UE with known location, the UE receives the reference point location of the beam indicated by the BS and determines the distance between the UE location and the reference point location. The UE then determines the sub-area of the UE and the corresponding RO resource according to the threshold(s) indicated by the BS.

[0043] In a first embodiment for time-based coverage segmentation, the BS indicates a reference timestamp of a common signaling transmission. The reference timestamp can be a timestamp of a synchronization signaling transmission sent by the BS or a timestamp of a broadcast signaling transmission sent by the BS. The BS then indicates a time threshold that segments the beam coverage into 2 sub-areas. The UEs in sub-area 1 will have a propagation delay less than the time threshold, while the UEs in sub-area 2 will have a propagation delay greater than or equal to (i.e., not less than) the time threshold. In general, the BS can indicate more than one time threshold in order to segment the beam coverage into more than two sub-areas with different propagation delays.

[0044] For time-based coverage segmentation, the measurement performed by the UE includes the propagation delay of the UE relative to the reference timestamp. Then, the UE determines the appropriate set of resources according to the comparison of the propagation delay determined based on the reference timestamp for the common signal with a time threshold, the first resource is selected from sub-region 1 if the measurement value is less than the time threshold, and the second resource is selected from sub-region 2 if the measurement value is greater than or equal to (i.e., not less than) the time threshold. In some embodiments, the first RO and the second RO are different. In other embodiments, the first RO and the second RO are the same but have different preambles.

[0045] In a second embodiment for time-based coverage segmentation, the BS indicates the association between ROs and sub-regions by allocating ROs equally among the sub-regions. FIG. 6 is a diagram showing an example of the mapping between ROs and sub-regions according to a third embodiment. As FIG. 6 shown, if prach_FDM = 1, which means 1 PRACH resource is configured in the frequency domain, and ssb_per_RO = 1, which means 1 SSB is mapped to 1 RO, then correspondingly 2 TDM ROs are available for 2 sub-regions. In FIG. 6 , the first RO 610 is associated with the first sub-region (which can be the first sub-region 220 and 320 of FIG. 2 to FIG. 3 ), and the second RO 620 is associated with the second sub-region (which can be the second sub-region 230 and 330 of FIG. 2 to FIG. 3 ). The first RO 610 and the second RO 620 share the frequency domain but have different time domains. The association between ROs and thresholds can be given by the following formula:

[0046]

[0047] where t is the propagation delay between the UE and the BS. Generally, if N 子区域 sub-regions are obtained with a given threshold(s), all available ROs are allocated equally among the N 子区域 sub-regions.

[0048] The sub-region indices are mapped to ROs in a specific order. First, within a single RO, the sub-region indices are mapped in ascending order of the preamble index. Second, the sub-region indices are mapped in ascending order of the frequency resource index of the FDM RO. Third, the sub-region indices are mapped in ascending order of the time resource index of the TDM RO within a PRACH slot. Fourth, the sub-region indices are mapped in ascending order of the index of the PRACH slot.

[0049] In a third embodiment for time-based coverage segmentation, the BS indicates the association between ROs and sub-regions by specifying ROs for each sub-region. Referring back toFIG. 5 If prach FDM = 4, which means 4 PRACH resources are configured in frequency domain, and ssb_per RO = 1, which means 1 SSB is mapped to 1 RO, then only 1 RO is available for 2 sub-areas in SSB1 accordingly. The association between RO and threshold can be given by the following formula:

[0050]

[0051] where t is the propagation delay between UE and BS. The sub-area index is then mapped to RO according to a specific order. First, within a single RO, the sub-area index is mapped in ascending order of preamble index. Second, the sub-area index is mapped in ascending order of frequency resource index of FDM RO. Third, the sub-area index is mapped in ascending order of time resource index of TDM RO within a PRACH slot. Fourth, the sub-area index is mapped in ascending order of index of PRACH slot. In general, if N 子区域 sub-areas are obtained with a given threshold(s), then all ROs are allocated according to the M i value indicated by BS for each sub-area.

[0052] In the fourth embodiment for time-based coverage segmentation, for a UE with synchronized timing with the BS, the UE receives a common signal with a transmission timestamp and determines the propagation delay between its reception time and transmission time. Then, the UE determines its sub-area and corresponding RO resource according to the threshold(s) indicated by the BS.

[0053] In the first embodiment for frequency offset-based coverage segmentation, in the application where the UE and BS share the same external timing system (e.g., GPS timing), the BS indicates the reference timestamp of a common signaling transmission (e.g., synchronization / broadcast). The BS also indicates a frequency offset threshold, which divides the beam coverage into 2 sub-areas. The UEs in sub-area 1 have a frequency offset less than the frequency offset threshold, while the UEs in sub-area 2 have a frequency offset greater than or equal to (i.e., not less than) the frequency offset. In general, the BS can indicate more than one frequency offset threshold in order to segment the beam coverage into more than two sub-areas with different frequency offsets.

[0054] For frequency offset based coverage segmentation, the measurement performed by the UE includes the frequency offset of the UE with respect to a reference timestamp. The UE determines the appropriate set of resources based on the comparison of the determined frequency offset with a frequency offset threshold, selecting the first resources of sub-region 1 if the measurement is less than the frequency offset threshold, and selecting the second resources of sub-region 2 if the measurement is greater than or equal to (i.e., not less than) the frequency offset threshold. In some embodiments, the first RO and the second RO are different. In other embodiments, the first RO and the second RO are the same but have different preambles.

[0055] In a second embodiment for frequency offset based coverage segmentation, the BS indicates the association between ROs and sub-regions by equally allocating ROs among sub-regions. Referring back to FIG. 6 If prach_FDM = 1, which means 1 PRACH resource is configured in the frequency domain, and ssb_per_RO = 1, which means 1 SSB resource is mapped to 1 RO, then accordingly 2 TDM ROs (e.g., first RO 610 and second RO 620) are available for 2 sub-regions. The association between ROs and thresholds can be given by:

[0056]

[0057] where fo is the frequency offset estimated by the UE. In general, if N 子区域 sub-regions are obtained with a given threshold(s), then all available ROs are equally allocated among the N 子区域 sub-regions.

[0058] The sub-region indices are mapped to ROs in a specific order. First, within a single RO, the sub-region indices are mapped in ascending order of preamble indices. Second, the sub-region indices are mapped in ascending order of frequency resource indices of FDM ROs. Third, the sub-region indices are mapped in ascending order of time resource indices of TDM ROs within a PRACH slot. Fourth, the sub-region indices are mapped in ascending order of indices of PRACH slots.

[0059] In a third embodiment for frequency offset based coverage segmentation, the BS indicates the association between ROs and sub-regions by specifying ROs for each sub-region. Referring back to FIG. 5 , prach_FDM = 4, which means 4 PRACH resources are configured in the frequency domain, and ssb_per_RO = 1, which means 1 SSB is mapped to 1 RO, so accordingly only 1 RO is available for 2 sub-regions in SSB1 (e.g., sub-regions 510 and 520 of first RO 530). The association between ROs and thresholds can be given by:

[0060]

[0061] where fo is the frequency offset estimated by the UE. The sub-region index is then mapped to ROs according to a specific order. First, within a single RO, the sub-region index is mapped in ascending order of preamble index. Second, the sub-region index is mapped in ascending order of frequency resource index of FDM ROs. Third, the sub-region index is mapped in ascending order of time resource index of TDM ROs within a PRACH slot. Fourth, the sub-region index is mapped in ascending order of index of PRACH slots. In general, if N 子区域 sub-regions are obtained with a given threshold(s), all ROs are allocated according to M i values indicated by the BS for each sub-region.

[0062] In a fourth embodiment for frequency offset based coverage split, the BS indicates a pre-compensated frequency offset corresponding to a given reference point location of the beam. For example, the reference point can be the lowest (or center) point of the beam. In another example, the reference point can be the symmetric center point of a symmetric beam shape.

[0063] In a fifth embodiment, when the UE and the BS share the same external timing system (e.g., GPS timing), the UE receives a plurality of common signals transmitted by the BS and estimates the experienced frequency offset by comparing the received time interval and the indicated time stamp interval between the plurality of common signals. The UE receives the (optional) existing pre-compensated frequency offset indicated by the BS. The total frequency offset is calculated by adding the UE’s estimated frequency offset and the BS’s pre-compensated frequency offset. The UE determines the UE’s sub-region and the corresponding RO resources according to the threshold(s) indicated by the BS.

[0064] According to several embodiments, the BS can indicate PRACH configurations for 2-step RACH or 4-step RACH. FIG. 7 is a flow diagram illustrating an exemplary method 700 for determining a RACH type according to various arrangements. As FIG. 7As shown, the method 700 is performed by a base station (e.g., non-terrestrial BS) 701 and a user equipment 702. At step 710, the BS 701 indicates network access procedure (e.g., RACH) type configurations (i.e., 2-step RACH and / or 4-step RACH), which can be RACH type flags in common signaling. At step 720, the BS 701 also indicates one or more reference signal received power (RSRP) thresholds for each network access procedure type. Each RSRP threshold is associated with a payload size threshold, which is pre-determined or indicated by the BS. Steps 710 and 720 can occur simultaneously or in any order (e.g., 710 before 720 or 720 before 710). Then, at step 730, the BS 701 indicates a corresponding RACH configuration for each indicated network access procedure type, respectively. The additional configurations for 2-step RACH include time-frequency resources of ROs and association with physical uplink shared channel (PUSCH) occasions (POs). The PO configuration includes one or more sets of time-frequency resources for different payload sizes. The association between RSRP thresholds, time-frequency resource sets, and payload sizes is pre-determined. Next, at step 740, the UE 702 determines the supported RACH type according to the received RACH type configurations and the one or more received RSRPs. Then, the UE 702 uses 2-step RACH if the UE’s RSRP measurement value (i.e., the UE’s measured power) is higher than the received RSRP threshold at step 750, and if the UE’s payload size is lower than the payload size threshold associated with the maximum power threshold below the measured power at step 760. If both conditions are met, the UE selects a set of time-frequency resources associated with the maximum power threshold below the measured power.

[0065] In a second embodiment, requirements on UE capability can be pre-determined or indicated by the BS and include at least one of GNSS, UE type, timing, pre-compensation, and / or local oscillator accuracy. A UE without GNSS or UE location information directly uses the 4-step RACH resources indicated by the BS according to the pre-determined or indicated limitations. These limitations or requirements on UE capability include one or more of positioning capability, UE type, timing, UE pre-compensation, or local oscillator accuracy. Aerial type of UE directly uses the 4-step RACH resources indicated by the BS according to the pre-determined limitations. A UE without synchronized timing with the BS directly uses the 4-step RACH resources indicated by the BS according to the pre-determined limitations. A UE without time and / or frequency pre-compensation directly uses the 4-step RACH resources indicated by the BS according to the pre-determined limitations. A UE without a sufficiently accurate / stable local oscillator directly uses the 4-step RACH resources indicated by the BS according to the pre-determined limitations. A local oscillator is determined to be sufficiently accurate based on a pre-determined criteria (e.g., I.O frequency offset > 10 ppm).

[0066] If there is partial or complete failure of transmission at 2-step RACH, there is a fallback from 2-step RACH to 4-step RACH if MSG_A preamble part is successfully detected but payload detection fails. FIG. 8 is a diagram illustrating an exemplary timeline of fallback to 4-step RACH according to various arrangements. FIG. 8 The time domain is taken as the x-axis. UE 802 sends MSG_A to BS 802 at 810. The time of 810 is taken as T0-TA UE is given, where T0is the expected reception time of MSG_A by the BS, TA UE is the time advance pre-compensated by the UE. At 820, BS 801 receives MSG_A and sends a fallback RAR indicating the remaining TA(TA BS ). TA BS equals T0'-T0, where T0' is the actual reception time of MSG_A by the BS (at 820 in FIG. 8 ). Thus, TA BS equals the interval between the actual and expected reception times of MSG_A by the BS. At 830, UE 802 receives the fallback RAR. UE 802 sends a payload retransmission at 840, and the payload retransmission is expected to be received by BS 801 at 850 (or T1). The value of T1-T0should be greater than or equal to:

[0067]

[0068] where RTT is the round trip time, TA RETX equals TA UEWith TA BS The sum of RTT and TA. UE Since both payload detection failures are unknown to the BS, their values ​​should be set to the maximum possible values. Maximum RTT is determined by the BS based on its beam deployment. Maximum TA... UE It is equal to half of the maximum RTT. Therefore, the value of T1-T0 should be greater than or equal to:

[0069] 2*TA BS +max(RTT) (8)

[0070] The time-frequency resources indicated in the back-off RAR used for payload retransmission shall comply with this limitation. The value of max(RTT) may be indicated by the BS in the common / dedicated signal to (multiple) UEs, or may be predetermined and known by the BS and (multiple) UEs.

[0071] Timing advance (TA) is determined during payload retransmission in the case of backtracking to 4-step RACH, and is sent by the BS to the UE as a timing advance command (TA CMD). FIG. 9 This is a flowchart illustrating an exemplary method 900 for determining and applying a TA. (See attached diagram.) FIG. 9 As shown, method 900 is performed by a base station (e.g., a non-terrestrial BS) 901 and a user equipment 902. At step 910, the UE 902 pre-compensates for the time offset of the UE during the MSG_A transmission and applies the pre-compensated time value (i.e., TA) to the base station. UE The MSG_A payload is included in the UE 902 payload. Then, at step 920, UE 902 transmits the MSG_A with a pre-compensated time offset. At step 930, UE 902 initiates its Random Access Response (RAR) monitoring window with a minimum RTT delay, which is determined by BS 901, predetermined, or calculated by UE 902. Steps 920 and 930 can occur simultaneously or in any order (e.g., 920 before 930 or 930 before 920). Next, if the MSG_A payload detection fails, BS 901 transmits a fallback RAR at step 940. In this case, the pre-compensated time value applied by UE 902 is unknown to the BS. The time-frequency resources used for payload retransmission are indicated in the fallback RAR. The time between when BS 901 receives the payload retransmission (i.e., T1) and when BS 901 expects to receive MSG_A (i.e., T0) is greater than or equal to the value in Equation 7. TACMD (i.e., TA) BS This is included in the rollback RAR, and it is assumed that the pre-compensation time on the UE 902 side is zero. Then, at step 950, UE 902 applies the indicated TA CMD plus the amount of the previous compensation.

[0072] If 2-step RACH is successful, there can still be a TA after the uplink (UL) transmission. FIG. 10 is a flow diagram illustrating an example method 1000 for determining and applying a TA. As FIG. 10 shown, the method 1000 is performed by a base station (e.g., non-terrestrial BS) 1001 and a user equipment 1002. At step 1010, the UE 1002 pre-compensates for a time offset of the UE in a MSG_A transmission and includes the pre-compensated time value in a MSG_A payload. Then, at step 1020, the UE 1002 transmits the MSG_A with the pre-compensated time offset. At step 1030, the UE 1002 starts a RAR monitoring window of the UE with a delay of a minimum RTT, the delay of the minimum RTT being determined or predetermined by the BS indication. Steps 1020 and 1030 can occur simultaneously or in any order (e.g., 1020 before 1030 or 1030 before 1020). Next, at step 1040, the BS 1001 transmits a RAR message to the UE 1002, the RAR message indicating successful detection of the MSG_A and including an UL grant for a subsequent UL transmission. A TA CMD is included in the UL grant and is an additional adjustment based on the pre-compensated time offset of the UE included in the MSG_A payload of the UE. This adjustment is different from the adjustment provided when 2-step RACH fails because the pre-compensated time offset is known to the BS 1001 in the case of successful 2-step RACH, whereas the value of the pre-compensated time offset is unknown but determinable to the BS 1001 in the case of unsuccessful 2-step RACH. At step 1050, if the UE 1002 successfully receives the RAR, the UE 1002 then applies the TA value in the subsequent UL transmission using the indicated UL grant. The TA value is the sum of the pre-compensated time offset of the UE included in the MSG_A payload of the UE and the TA CMD value indicated by the BS 1001 in the RAR.

[0073] FIG. 11A is a flow diagram illustrating an example wireless communication method 1100 for RACH occasions, in accordance with various arrangements. Referring to FIG. 2 to FIG. 3 and FIG. 7 to FIG. 9 , the method 1100 can be performed by a BS (e.g., a non-terrestrial BS described herein). The method 1100 begins, at step 1110, with the BS indicating, to a wireless communication device (e.g., a UE), at least one set of resources for network access. Then, at step 1120, the BS performs a network access procedure with the UE based on the indicated set of resources for network access.

[0074] FIG. 11Bis a flowchart illustrating an exemplary wireless communication method 1150 for RACH occasions, in accordance with various arrangements. Reference is made to FIG. 1 through FIG. 7 to FIG. 10 Method 1150 can be performed by a UE. Method 1150 begins at step 1160, where the UE receives, from a BS, an indication of at least one set of resources for network access. At step 1170, the UE determines a selected set of resources for network access based on measurements performed by the UE. Then, at step 1180, the UE performs a network access procedure with the BS based on the selected set of resources.

[0075] FIG. 12A A block diagram illustrating an exemplary BS 1202 (e.g., a non-terrestrial BS described herein), in accordance with some embodiments of the disclosure is shown. FIG. 12B A block diagram illustrating an exemplary UE 1201, in accordance with some embodiments of the disclosure is shown. Reference is made to FIG. 1 through FIG. 12B UE 1201 (e.g., a wireless communication device, terminal, mobile device, mobile user, etc.) is an exemplary implementation of a UE described herein, and BS 1202 is an exemplary implementation of a BS described herein.

[0076] BS 1202 and UE 1201 can include components and elements that are configured to support known or traditional operational features that need not be described in detail herein. In one illustrative embodiment, as described above, BS 1202 and UE 1201 can be used to communicate (e.g., transmit and receive) data symbols in a wireless communication environment. For example, BS 1202 can be a BS (e.g., gNB, eNB, etc.), a server, a node, or any suitable computing device for implementing various network functions.

[0077] BS 1202 includes a transceiver module 1210, an antenna 1212, a processor module 1214, a memory module 1216, and a network communication module 1218. Modules 1210, 1212, 1214, 1216, and 1218 are operatively coupled and interconnected to each other via a data communication bus 1220. UE 1201 includes a UE transceiver module 1230, a UE antenna 1232, a UE memory module 1234, and a UE processor module 1236. Modules 1230, 1232, 1234, and 1236 are operatively coupled and interconnected to each other via a data communication bus 1240. BS 1202 communicates with UE 1201 or another BS via a communication channel, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0078] As those skilled in the art will appreciate, BS 1202 and UE 1201 can also include components and elements other than those shown in FIGS. 12 and 13, such as power supplies, power circuitry, power management modules, one or more processors, memory, volatile memory, non-volatile memory, buffers, timing modules, etc. FIG. 12A and FIG. 12Bany number of modules beyond those shown. The various illustrative blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system. The embodiments described herein can be implemented in any suitable manner for each particular application, but any implementation decisions should not be interpreted as a limitation on the scope of the present disclosure.

[0079] According to some embodiments, the UE transceiver 1230 includes a radio frequency (RF) transmitter and an RF receiver, each including circuitry coupled to an antenna 1232. A duplexing switch (not shown) can alternatively couple the RF transmitter or receiver to the antenna in a time-division duplexing manner. Similarly, according to some embodiments, the transceiver 1210 includes an RF transmitter and an RF receiver, each with circuitry coupled to an antenna 1212 or to an antenna of another BS. A duplexing switch can alternatively couple the RF transmitter or receiver to the antenna 1212 in a time-division duplexing manner. The operations of these two transceiver modules 1210 and 1230 can be coordinated in time so that the receiver circuitry is coupled to the antenna 1232 for receiving transmissions over the wireless transmission link at the same time that the transmitter is coupled to the antenna 1212 for transmitting. In some embodiments, there is a close time synchronization with minimal guard time between changes in duplex direction.

[0080] The UE transceiver 1230 and the transceiver 1210 are configured to communicate via a wireless data communication link and in cooperation with an appropriately configured RF antenna arrangement 1212 / 1232 capable of supporting a particular wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver 1230 and the transceiver 1210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it will be appreciated that the present disclosure need not be limited to a particular standard and associated protocols in application. Rather, the UE transceiver 1230 and the BS transceiver 1210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0081] The transceiver 1210 and the transceiver of the other BS (e.g., but not limited to, the transceiver 1210) are configured to communicate via a wireless data communication link and in cooperation with an appropriately configured RF antenna arrangement capable of supporting a particular wireless communication protocol and modulation scheme. In some illustrative embodiments, the transceiver 1210 and the transceiver of the other BS are configured to support industry standards such as LTE and emerging 5G standards. However, it should be appreciated that the present disclosure need not be limited in application to particular standards and associated protocols. Rather, the transceiver 1210 and the transceiver of the other BS can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0082] According to various embodiments, the BS 1202 can be a BS such as, but not limited to, an eNB, a serving eNB, a target eNB, a femto station, or a pico station. The BS 1202 can be a RN, a DeNB, or a gNB. In some embodiments, the UE 1201 can be implemented in various types of user equipment such as a mobile phone, a smart phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, a wearable computing device, etc. The processor modules 1214 and 1236 can be implemented or realized with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, the processor can be implemented as a microprocessor, a controller, a microcontroller, a state machine, etc. The processor can also be implemented as a combination of a

[0083] Furthermore, the methodologies or algorithms disclosed herein can be embodied directly in hardware, in a software module specifically programmed for execution by, e.g., processor module 1214 and 1236, respectively, in firmware, in an application-specific integrated circuit (ASIC), in a programmable logic array (PLA), in a programmable logic controller (PLC), in a processor, or the like, or any combination thereof. The memory modules 1216 and 1234 can be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. In this regard, the memory modules 1216 and 1234 can be coupled to the processor modules 1214 and 1236, respectively, such that the processor modules 1214 and 1236 can read information from, and write information to, the memory modules 1216 and 1234, respectively. The memory modules 1216 and 1234 can also be integral to the processor modules 1214 and 1236, respectively. In some embodiments, the memory modules 1216 and 1234 can each include cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor modules 1214 and 1236, respectively. The memory modules 1216 and 1234 can also each include non-volatile memory for storing instructions to be executed by the processor modules 1214 and 1236, respectively.

[0084] The network communication module 1218 generally represents the hardware, software, firmware, processing logic and / or other components that enable two-way communication to and from the transceiver 1210 with other network components and communication nodes in communication with the BS 1202. For example, the network communication module 1218 can be configured to support Internet or WiMAX traffic. In one deployment, but not limited to, the network communication module 1218 provides an 802.3 Ethernet interface such that the transceiver 1210 can communicate with a conventional Ethernet-based computer network. In this manner, the network communication module 1218 can include a physical interface (e.g., a mobile switching center (MSC)) for connection to a computer network. In some embodiments, the network communication module 1218 includes a fiber optic transmission connection configured to connect the BS 1202 to a core network. As used herein with respect to a specified operation or function, the terms "configured to," "adapted to," and variations thereof mean that the device, component, circuit, structure, machine, signal, etc. is physically constructed, programmed, formatted, and / or arranged to perform the specified operation or function.

[0085] While various embodiments of the present scheme have been described above, it should be understood that they have been presented by way of example only, and not in limitation. Likewise, the various figures can depict an example architectural or configuration scheme that is provided for purposes of illustration only. However, as will be readily understood by those skilled in the art, the present scheme is not limited to the illustrated example architectures or configurations, but can be carried out using a variety of alternative architectures and configurations. Furthermore, one or more features of one embodiment can be combined with one or more features of another embodiment as will be readily understood by those of ordinary skill in the art. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described illustrative embodiments.

[0086] It should also be understood that any reference to an element herein using a designation such as "first," "second," and so forth does not limit the quantity or order of those elements. Rather, these designations can be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed or that the first element must precede the second element.

[0087] In addition, those of ordinary skill in the art will appreciate that any of various different technical means can be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, and symbols discussed above can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0088] Those of ordinary skill in the art will further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a number of logic

[0089] Furthermore, those of ordinary skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithms described herein can be implemented or performed with integrated circuits (ICs): general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, or any combination thereof. The logical blocks, modules, and circuits can also include antennas and / or transceivers to communicate with various components within a network or device. The general purpose processor can be a microprocessor, but in the alternative, can be any conventional processor, controller, or state machine. The processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration.

[0090] If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Therefore, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program or code from one place to another. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact discs and laser discs.

[0091] In this document, the term "module" as used herein, refers to software, firmware, hardware, and any combination of these elements that is used to implement the associated functionality described herein. Additionally, a variety of means for implementing the various modules described herein are contemplated, as will be apparent to one of ordinary skill in the art. For example, the functionality of two or more separate modules can be implemented by a single module, and vice versa. Lines of functionality among various modules can vary as desired.

[0092] Additionally, memory or other storage devices and communication components can be used in embodiments of the present solution. It will be appreciated that, for clarity, the above description has described embodiments of the solution with reference to different functional units and processors. However, it will be apparent that any appropriate distribution of functionality between different functional units, processing logic elements or domains can be used without detracting from the solution. For example, functionality illustrated to be performed by separate processing logic elements or controllers can be performed by the same processing logic element or controller. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[0093] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the scope of this disclosure. Thus, the disclosure is not to be limited to the implementations presented, but is to be accorded the broadest scope consistent with the features and principles disclosed herein and the following claims.

Claims

1. A method of wireless communication, comprising: indicating, by a base station to a wireless communication device, at least one set of resources for network access by: a reference point of a beam of a cell of the base station; and one or more distance thresholds, wherein the beam comprises a plurality of sub-areas, each of the plurality of sub-areas is individually mapped to one of a plurality of time domain resources according to a particular order, the at least one set of resources comprises at least one of the plurality of time domain resources; performing, by the base station, a network access procedure with the wireless communication device based on the indicated at least one set of resources for network access. the resource for network access comprises at least one of:

2. The method of claim 1, wherein, a PRACH occasion; or a PRACH preamble index; or a PUSCH occasion for MSG_A in 2-step RACH. each of the at least one set of resources for network access is associated with at least one of:

3. The method of claim 1, wherein, the cell of the base station, the beam of the cell, a sub-area of the plurality of sub-areas of the beam, a type of the wireless communication device, a capability of the wireless communication device, or a frequency portion of the cell. the reference point comprises one of:

4. The method of claim 1, wherein, a lowest point of the beam; or a nearest point to the base station; or a symmetric center point of the beam. 5.The method of claim 1, further comprising indicating, by the base station, a network access procedure type configuration, one or more power thresholds for selecting a plurality of network access procedure types. each of the one or more power thresholds is associated with an effective payload size threshold, the effective payload size threshold is pre-determined or indicated by the base station.

6. The method of claim 5, wherein, 7.The method of claim 1, further comprising transmitting, by the base station to the wireless communication device, a timing advance command (TA CMD) when falling back from a first type of the network access procedure to a second type of the network access procedure. indicating, by the base station to the wireless communication device, a mapping between the plurality of time domain resources and the plurality of sub-areas, wherein the mapping comprises equally allocating a plurality of time domain resources among the plurality of sub-areas in a frequency domain.

8. The method of claim 1, further comprising: indices of the plurality of sub-areas are mapped in ascending order of frequency resource indices of the plurality of time domain resources, and wherein the plurality of time domain resources are frequency division multiplexed.

9. The method of claim 1, wherein, the order comprises:

10. The method of claim 1, wherein, first, indices of the plurality of sub-areas are mapped in ascending order of preamble indices within one time domain resource; second, indices of the plurality of sub-areas are mapped in ascending order of frequency resource indices of frequency division multiplexed time domain resources; third, indices of the plurality of sub-areas are mapped in ascending order of time resource indices of time division multiplexed time domain resources into another time domain resource. indicating, by the base station to the wireless communication device, a mapping between the plurality of time domain resources and the plurality of sub-areas, wherein the mapping comprises unequally allocating the plurality of time domain resources among the plurality of sub-areas.

11. The method of claim 1, further comprising: ​ 12. The method of claim 1, further comprising: indicating, by the base station to the wireless communication device, a mapping between the plurality of time domain resources and the plurality of sub-regions, wherein the mapping comprises an equal allocation of the plurality of time domain resources among the plurality of sub-regions in time domain.

13. A wireless communication device comprising at least one processor and a memory, wherein, the at least one processor is configured to read code from the memory and implement a method recited in any of claims 1 to 12.

14. A computer program product comprising a computer readable program medium code stored thereon, the code, when executed by at least one processor, causing the at least one processor to implement a method recited in any of claims 1 to 12.

15. A method of wireless communication, comprising: receiving, by a wireless communication device from a base station, an indication of at least one set of resources for network access, the indication comprising: a reference point of a beam of a cell of the base station; and one or more distance thresholds, wherein the beam comprises a plurality of sub-regions, each of the plurality of sub-regions individually mapped to one of a plurality of time domain resources according to a particular order, the at least one set of resources comprising at least one of the plurality of time domain resources; determining, by the wireless communication device, a selected set of resources based on measurements performed by the wireless communication device; and performing, by the wireless communication device, a network access procedure with the base station based on the selected set of resources.

16. The method of claim 15, wherein, the resources for network access comprise at least one of: a PRACH occasion; or a PRACH preamble index; or a PUSCH occasion for MSG_A in 2-step RACH.

17. The method of claim 15, wherein, each of the at least one set of resources for network access is associated with at least one of: the cell of the base station, the beam of the cell, a sub-region of the plurality of sub-regions of the beam, a type of the wireless communication device, a capability of the wireless communication device, or a frequency portion of the cell.

18. The method of claim 15, further comprising: receiving, by the wireless communication device from the base station, an access procedure type configuration and one or more power thresholds for selecting one or more sets of resources for the network access procedure; determining, by the wireless communication device according to the access procedure type configuration, a supported resource of the one or more sets of resources for the network access procedure.

19. The method of claim 18, further comprising selecting, by the wireless communication device, a 2-step network access procedure as the network access procedure in response to determining that: a measured power determined by the wireless communication device is above one of the power thresholds; and a payload size is below a payload size threshold associated with a maximum power threshold of the one or more power thresholds below the measured power.

20. The method of claim 15, further comprising selecting, by the wireless communication according to a capability of the wireless communication device, a set of the one or more sets of resources for the network access procedure, the capability comprising at least one of: a maximum payload size; or a maximum power threshold. one or more of a positioning capability, a type of the wireless communication device, a timing of the wireless communication device, a pre-compensation value of the wireless communication device, or a local oscillator precision of the wireless communication device, wherein the capability is predetermined or received from the base station.

21. The method of claim 15, further comprising: receiving, by the wireless communication device, a timing advance command, TA CMD, from the base station; and applying, by the wireless communication device, the TA CMD in a payload retransmission. applying, by the wireless communication device, the TA CMD comprises applying, in response to determining that an uplink, UL, grant and a received TA CMD are indicated in a random access response, RAR, from the base station, a sum of the received TA CMD and a pre-compensation time offset.

22. The method of claim 21, wherein, the RAR comprises time-frequency resources for a payload retransmission indicated by the base station, 23. The method of claim 22, wherein, wherein a time interval between an expected reception time of MSG_A and the payload retransmission is higher than or equal to a sum of a maximum of twice the TA CMD and a round trip time, RTT, indicated by the base station or predetermined. the at least one processor is configured to read code from the memory and implement a method as claimed in any of claims 15 to 23.

24. A wireless communication device comprising at least one processor and a memory, wherein 25. A computer program product comprising a computer readable program medium code stored thereon, the code, when executed by at least one processor, causing the at least one processor to implement a method as claimed in any of claims 15 to 23. ​

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