HARQ process identification and soft buffer management for non-terrestrial networks

Abstract

A method of hybrid automatic repeat request (HARQ) processing for non-terrestrial networks. In some embodiments, the method includes receiving, by a user equipment (UE), a first downlink control information (DCI), the first DCI including a first hybrid automatic repeat request (HARQ) process identifier (ID); calculating a first HARQ process number based on the first HARQ process ID and a slot number associated with the first DCI; and processing a first data block via a HARQ process associated with the first HARQ process number.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to (i) U.S. Provisional Application No. 63 / 057,211, filed July 27, 2020, entitled “Method for HARQ Process Identification and Soft Buffer Management for Non-Terrestrial Networks”; and (ii) U.S. Provisional Application No. 63 / 090,621, filed October 12, 2020, entitled “Method for HARQ Process Identification and Soft Buffer Management for Non-Terrestrial Networks”. The entire contents of both applications are incorporated herein by reference. Technical Field

[0003] One or more aspects of embodiments of this disclosure relate to mobile communications, and more specifically, to mobile communications over non-terrestrial networks. Background Technology

[0004] In mobile communication systems, it can sometimes be advantageous for User Equipment (UE) to communicate with non-terrestrial nodes (e.g., with communication satellites). In such cases, the round-trip latency may be significantly greater than the round-trip latency between the UE and the terrestrial network node. This can present challenges; for example, 16 concurrent HARQ processes may be too few to provide acceptable data throughput for some applications, while increasing the number of HARQ processes may strain the UE's buffering capacity.

[0005] Therefore, a system and method for managing HARQ processes and soft buffers in non-terrestrial networks are needed. Summary of the Invention

[0006] According to embodiments of this disclosure, a method is provided, comprising: receiving first downlink control information (DCI) by a user equipment (UE), the first DCI including a first hybrid automatic repeat request (HARQ) process identifier (ID); calculating a first HARQ process number based on the first HARQ process ID and a timeslot number associated with the first DCI; and processing a first data block via a HARQ process associated with the first HARQ process number.

[0007] In some embodiments, processing of the first data block includes encoding and sending the first data block.

[0008] In some embodiments, processing of the first data block includes receiving and decoding the first data block.

[0009] In some embodiments, the method further includes: determining the integrity of a first data block and sending an ACK or NACK based on the integrity of the first data block.

[0010] In some embodiments, the method further includes: receiving a second DCI from a user equipment, the second DCI including a second HARQ process ID; calculating a second HARQ process number based on the second HARQ process ID and a timeslot number associated with the second DCI; determining that the second HARQ process number is equal to a first HARQ process number; receiving a second data block via a HARQ process associated with the second HARQ process number; and decoding a first data block using the second data block.

[0011] In some embodiments, the calculation of the first HARQ process number includes: resetting N at the first radio frame boundary. c Bit counter; in K s During each radio frame, N increments once per time slot. c Bit counter, K s It is an integer greater than 0; and N c The value of the bit counter is combined with the HARQ process ID to form the HARQ process number.

[0012] In some embodiments, K s It is to satisfy The smallest positive integer, where It is the number of time slots per frame for the subcarrier spacing configuration μ.

[0013] In some embodiments, calculating the first HARQ process number includes, according to HARQ ID，Actual =[(CurrentSlotMOD 2)+(HARQ ID，DCI ×2)]MOD N HARQ Calculate the first HARQ process number, where It is the HARQ process ID, N HARQ It is the HARQ process number supported by the UE.

[0014] In some embodiments, calculating the first HARQ process number includes combining one or more bits of the HARQ process ID and the slot number to form the first HARQ process number, wherein the most significant bit of the first HARQ process number is one bit of the HARQ process ID, and the least significant bit of the first HARQ process number is one bit of the HARQ process ID.

[0015] In some embodiments, the method further includes storing a first data block in a circular buffer having a size (N). soft -N soft，act ) / N HARQ , where: N HARQ N is the number of concurrent HARQ processes. soft N is an estimate of the total soft buffer size available within the UE for each frequency band or combination of frequency bands supported by the UE.soft，act This is the soft buffer requirement for all component carriers except the NTN carrier.

[0016] In some embodiments, the method further includes storing a first data block in a soft buffer, the soft buffer being of size [missing information]. The cyclic buffer is within 20% of the total, where: It is the reference buffer size used for the ground link; and α is equal to 16 as a ratio of the number of HARQ processes in the PDSCH.

[0017] According to embodiments of this disclosure, a system is provided, including: a user equipment (UE), the UE including: a radio device; and processing circuitry configured to: receive first downlink control information (DCI), the first DCI including a first hybrid automatic repeat request (HARQ) process identifier (ID); calculate a first HARQ process number based on the first HARQ process ID and a timeslot number associated with the first DCI; and process a first data block via a HARQ process associated with the first HARQ process number.

[0018] In some embodiments, processing of the first data block includes encoding and sending the first data block.

[0019] In some embodiments, processing of the first data block includes receiving and decoding the first data block.

[0020] In some embodiments, the system further includes: determining the integrity of the first data block and sending an ACK or NACK based on the integrity of the first data block.

[0021] In some embodiments, the processing circuitry is further configured to: receive a second DCI, the second DCI including a second HARQ process ID; calculate a second HARQ process number based on the second HARQ process ID and a timeslot number associated with the second DCI; determine that the second HARQ process number is equal to a first HARQ process number; receive a second data block via a HARQ process associated with the second HARQ process number; and decode a first data block using the second data block.

[0022] In some embodiments, the calculation of the first HARQ process number includes: resetting N at the first radio frame boundary. c Bit counter; in K s During each radio frame, N increments once per time slot. c Bit counter, K s It is an integer greater than 0; and N c The value of the bit counter is combined with the HARQ process ID to form the HARQ process number.

[0023] In some embodiments, Ks It is to satisfy The smallest positive integer, where It is the number of time slots per frame for the subcarrier spacing configuration μ.

[0024] According to embodiments of this disclosure, a system is provided, including: a user equipment (UE), the UE including: a radio device; and means for processing, the means for processing being configured to: receive first downlink control information (DCI) via a time slot of a frame, the first DCI including a first hybrid automatic repeat request (HARQ) process indicator (ID); calculate a first HARQ process number based on the first HARQ process ID and the time slot position of the first DCI in the frame; and receive and decode a first data block via a HARQ process associated with the first HARQ process number.

[0025] In some embodiments, the means for processing is further configured to: receive second downlink control information (DCI) via a time slot of a frame, the second DCI including a second HARQ process ID; calculate a second HARQ process number based on the second HARQ process ID and the time slot position of the second DCI in the frame; determine that the second HARQ process number is equal to a first HARQ process number; receive a second data block via a HARQ process associated with the second HARQ process number; and decode a first data block using the second data block. Attached Figure Description

[0026] These and other features and advantages of this disclosure will be understood and appreciated by referring to the specification, claims and drawings, wherein:

[0027] Figure 1 n is an embodiment of this disclosure PRB，LBRM A table of values;

[0028] Figure 2A This is a diagram of the bit structure of the HARQ process number according to an embodiment of this disclosure;

[0029] Figure 2B This is a bit structure diagram of a HARQ process number with a 2-bit time slot counter;

[0030] Figure 2C This is a time slot counter diagram according to an embodiment of the present disclosure;

[0031] Figure 2D This is a time slot counter diagram according to an embodiment of the present disclosure;

[0032] Figure 2E This is a time slot counter diagram according to an embodiment of the present disclosure;

[0033] Figure 2F It is a table of HARQ ID processes allocated to time slots according to embodiments of this disclosure;

[0034] Figure 3 This is a table showing the subcarrier spacing index for subcarrier spacing according to embodiments of the present disclosure;

[0035] Figure 4 This is a flowchart of a method according to an embodiment of the present disclosure; and

[0036] Figure 5 This is a block diagram of a part of a mobile communication system according to an embodiment of the present disclosure. Detailed Implementation

[0037] The detailed description set forth below with reference to the accompanying drawings is intended as a description of exemplary embodiments of a system and method for HARQ process identification and soft buffer management for non-terrestrial networks provided in this disclosure, and is not intended to represent the only form in which this disclosure can be constructed or utilized. This description illustrates features of the disclosure in conjunction with the illustrated embodiments. However, it should be understood that the same or equivalent functionality and structure can be implemented through different embodiments, which are also intended to be included within the scope of this disclosure. As shown elsewhere herein, similar element designations are intended to denote similar elements or features.

[0038] The 3rd Generation Partnership Project (3GPP) has studied the role and advantages of satellites in 5G New Radio (NR). This effort led to specific requirements for supporting satellite access in 3GPP TS 22.261v 17.1.0 "Service Requirements for 5G Systems; Phase 1". Within this framework, it is recognized that satellite coverage, as part of the 5G NR access technology portfolio, brings added value, particularly for mission-critical and industrial applications where ubiquitous coverage and availability are critical.

[0039] Satellites refer to spacecraft in low Earth orbit (LEO), medium Earth orbit (MEO), geostationary orbit (GEO), or highly elliptical orbit (HEO). In addition to satellites, non-terrestrial networks (NTNs) refer to networks or network segments that use airborne or spaceborne vehicles for transmission. Airborne vehicles refer to high-altitude platform stations (HAPS) that include unmanned aerial vehicle systems (UAS), including tethered UAS that are lighter and heavier than air UAS, operating at altitudes typically between 8 and 50 kilometers and are usually quasi-stationary.

[0040] In this way, 5G NR systems can be equipped to provide services using satellite access, and it can support service continuity between terrestrial 5G NR access and satellite-based access networks owned by the same operator, or through protocols between different operators. To provide services using satellite access, the air interface of the 5G system can support one-way latency of up to 300ms, or round-trip latency of approximately 600ms as specified in 3GPP TS 38.821 v16.0.0 “NR Solution for Supporting Non-Terrestrial Networks (NTN) (Version 16)”.

[0041] In NR, rate matching of LDPC codes is defined per code block and consists of bit selection and bit interleaving. Soft buffer management and bit count can be significantly affected by the bit selection stage. Currently in NR, bit selection and soft buffer management are performed as follows.

[0042] Assume the encoded bit sequence is d0, d1, ..., d N-1 Thus, N is the number of encoded bits in each code block. This bit sequence is the input to the bit selection block. This sequence is first written into the r-th code block of length N. cb A circular buffer. N cb Select as:

[0043] N cb =min(N, N) ref (1)

[0044] Where N ref Defined as (with "." indicating multiplication):

[0045]

[0046] Among them, R LBRM Is it set to R? LBRM = 2 / 3 of the finite buffer rate matching (LBRM) default code rate value, where C is the number of code blocks in the transport block as determined by Clause 5.2.2 of 3GPP TS 38.212 v16.1.0 "Multiplexing and Channel Coding (Revision 16)" (hereinafter referred to as "TS 38.212"). TBS LBRM The calculation is described below. If the transport block size is greater than the maximum code block size K... cb Then, the input bit sequence is segmented, and an additional L=24-bit CRC sequence is appended to each code block. For LDPC base graph 1, the maximum code block size is: K cb =8448, for LDPC base diagram 2, the maximum code block size is: K cb =3840. Therefore, C is determined according to the following equation:

[0047]

[0048] For example, if TBS = 15000 and base chart 1 is used, then C = 2.

[0049] TBS LBRM It is determined according to Clause 6.1.4.2 of 3GPP TS 38.214 v16.0.0 "Physical Layer Procedures for Data (Revision 16)" (hereinafter referred to as TS 38.214) regarding the Uplink (UL) Shared Channel (UL-SCH) and Clause 5.1.3.2 of TS 38.214 regarding the Downlink (DL) Shared Channel and Physical Channel (DL-SCH / PCH). The following discussion focuses on DL-SCH / PCH; the calculation and parameter settings for UL-SCH are similar.

[0050] First, the intermediate number of information bits N is defined and obtained in the following way. info :

[0051] N info =N RE .RQ m .v (4)

[0052] In equation (4), N RE The maximum number of resource elements (REs) occupied is set to 156 × n. PRB，LBRM .according to Figure 1 Table settings n PRB，LBRM The value of . For example Figure 1 It can be seen that, within the preset range shown, n PRB，LBRM The value is always quantized to the maximum value. R is set to the maximum value of the DL-SCH coding rate, which is 948 / 1024.

[0053] For Q m If the higher-layer parameter mcs-Table given by the pdsch-Config of at least one DL bandwidth portion (BWP) of the serving cell is set to "qam256", then it is assumed that the maximum modulation order Q of the DL-SCH is Q. m =8; otherwise, assume the maximum modulation order Q of DL-SCH m=6. v is the maximum number of layers in a transport block (TB) of the DL-SCH / PCH, given by min(X, 4). If the higher-layer parameter maxMIMO-Layers of the PDSCH-ServingCellConfig of the serving cell is configured, then X is given by this parameter. Otherwise, X is given by the maximum number of layers of the Physical Downlink Shared Channel (PDSCH) supported by the user equipment (UE) of the serving cell. As used herein, the phrase “user equipment” is used as a countable noun, even though the noun it contains (“equipment”) may be uncountable in ordinary English. Similarly, the phrase Downlink Control Information (DCI) is also used as a countable noun.

[0054] Once the middle number N of the information bits info Based on the above calculations, then TBS LBRM The following is confirmed.

[0055] First, the intermediate number of the quantization of the information bits can be calculated:

[0056]

[0057] in

[0058] If N′ info >8424, then TRS LBRM Calculation as follows

[0059]

[0060] in,

[0061] If N′ info ≤8424, then TRS LBRM Calculation as follows

[0062]

[0063] Once TBS is calculated LBRM Then, equations (2) and (1) can be used to calculate the size N of the circular buffer. cb .

[0064] Since third-generation (3G) mobile communication systems, HARQ has been adopted by most mobile communication systems. In NTN, the round-trip time (RTD) for GEO satellites is approximately 600ms, while for LEO satellites it can reach tens of milliseconds. For GEO satellites, retransmission may not be preferred due to the very large RTD, while for LEO satellites, HARQ can still be used, but with limitations on the number of retransmissions to ensure latency remains within acceptable limits. Furthermore, the use of HARQ depends on the type of service: for LEO satellites, it might be feasible to use HARQ for regular data traffic, such as web browsing; however, using HARQ for most streaming services may not be wise. In HARQ, data packets that are not successfully decoded can be retransmitted with the same HARQ process ID and then decoded at the receiver using previously received data packets. The term "decoding" here includes both successful and unsuccessful decoding.

[0065] To support the high data rates of LEO satellites, the number of HARQ processes may exceed the number of time slots within a time period as long as the RTD. For a 32ms RTD and a 120kHz subcarrier spacing (SCS), the number of HARQ processes could be as high as 256. While accommodating such a large number of concurrent HARQ processes may be challenging for the UE, the typically large RTD of NTN requires support for more concurrent HARQ processes than the existing 16 processes; therefore, NTN applications should support at least 32 or 64 concurrent HARQ processes. On the other hand, it may not be desirable to further increase the number of HARQ bits in each downlink control information (DCI). Therefore, a system and method are needed that supports more than 16 HARQ process IDs while maintaining the existing 4 HARQ bits in the DCI.

[0066] In addition, in some embodiments, the number of concurrent HARQ processes is increased, and the soft buffer management on the receiver side is also modified to ensure that there is sufficient allocated memory in the receiver to accommodate the increased number of concurrent HARQ processes configured by the network.

[0067] In one embodiment, the HARQ process number is constructed using the HARQ process identifier (HARQ process ID) field in the DCI and the slot number. The 4-bit process ID field in the DCI is used as the most significant bit (MSB), N c The bit virtual slot counter is used as the least significant bit (LSB) to construct the HARQ process number 205, such as... Figure 2A As shown. Thus, the number of supported concurrent HARQ processes can be up to the existing 16 HARQ processes supported by the 4-bit field in the DCI. The slot counter determines the slot number associated with the DCI. As used herein, the “slot number” of a slot is the value of the slot counter during that slot, and the “slot number associated with the DCI” is the slot number of any slot associated with the DCI; the slot associated with the DCI can be the slot containing the DCI, the first slot of a PDSCH or PUSCH scheduled by the DCI, or (if the PDSCH or PUSCH extends across a slot boundary) the last slot of a PDSCH or PUSCH scheduled by the DCI.

[0068] For example, if a 2-bit time slot counter is used ( Figure 2B Using the 'HARQ process ID' to construct HARQ process ID 205, 64 (=16×2^2) concurrent HARQ processes are supported. The bits of the time slot counter can be appended to the right of the HARQ process ID, making them the least significant bits of the HARQ process ID (e.g., ...). Figure 2B and 2C (as shown), or the order of the bit combinations can be different. For example, the bits of the time slot counter are inserted in the middle of the HARQ process ID (therefore, the most significant bit of the HARQ process number is a bit of the HARQ process ID, and the least significant bit of the HARQ process number is also a bit of the HARQ process ID).

[0069] N c The bit slot counter begins counting from the beginning of the 5G radio frame boundary. In some embodiments, the slot counter is reset at the end of each radio frame (e.g., reset to zero, or reset to some other starting value). In other embodiments, to ensure that the HARQ process ID is distributed fairly and constantly over time, N... c The bit slot counter runs freely until it reaches its maximum value and is reset (or resets itself, for example, due to overflow). In other words, for K s radio frames, N c The bit slot counter operates without being reset, where K s It is the smallest positive integer that satisfies the following:

[0070]

[0071] in It is the number of time slots per frame for the subcarrier spacing configuration μ.

[0072] For the actual situation of 5G NTN, the 4-bit DCI field supports 16 process IDs, and only seeks to support up to 32 or 64 process IDs, which respectively only require 1-bit or 2-bit slot counters. In this case, for a 1-bit slot counter, K in equation (5) sFor all subcarrier spacing configurations, it will always be 1. For a 2-bit slot counter, as... Figure 2C As shown, for a subcarrier spacing of 15kHz, i.e., μ = 0, K s K will be only 2 for all other subcarrier spacing configurations. s The value will be 1. Figure 2D and Figure 2E Two examples are shown, one with μ=1 and the other with μ=2.

[0073] In such an implementation, the scheduler can only schedule a limited set of HARQ process IDs within a given time slot. As a general rule, if N... c A bit-slot counter can then be used every... A given HARQ process is scheduled using a time slot. For example, if a 2-bit time slot counter is used, a given HARQ process ID can be scheduled every 4th time slot. Figure 2F The table shows an example of how to use a 2-bit time slot counter to allocate HARQ process IDs across different time slots to schedule timings.

[0074] In another embodiment, using a slot-based method, up to 32 HARQ processes can be supported using only a 4-bit DCI field. If the total number of HARQ processes is represented as N... HARQ The HARQ process number indicator in DCI is represented as HARQ. ID，DCI Then the current time slot index can be represented as:

[0075] CurrentSlot = 2 μ ×10×SFN+SlotNum (6)

[0076] Where μ is the subcarrier spacing index, SFN is the system frame number, and SlotNum is the slot number within the frame. Figure 3 In the table, the subcarrier spacing index μ is given for several values ​​of the subcarrier spacing.

[0077] HARQ process number based on time slots ID，Actual It can be represented as follows:

[0078] HARQ ID，Actual =[(CurrentSlot MOD 2)+(HARQ ID，DCI ×2)]MOD N HARQ (7)

[0079] in, Only when the configured HARQ process number (N) is HARQ The above method is defined only when N is greater than 16. HARQIf the value is ≤16, then the traditional NR HARQ process ID can be used, that is, the 4-bit HARQ process ID in DCI represents the HARQ process number.

[0080] In some embodiments, SlotNum is not a slot number in a frame, but is reset to 0 every 1024 frames; thus, before being reset to 0, it can be counted up to a number of slots less than the number of slots in 1024 frames (e.g., if there are 10 slots per frame, it counts up to 10239). In some embodiments, SlotNum is used instead of CurrentSlot in equation (7).

[0081] The methods described herein apply to HARQ process number identification for uplink and downlink transmissions: for example, when providing resource allocation for the Physical Uplink Shared Channel (PUSCH) using DCI format 0_0 or DCI format 0_1, or when providing resource allocation for the PDSCH using DCI format 1_0 or DCI format 1_1. These methods also apply to all types of dynamic allocation, such as when, for uplink transmissions, the configured licensed transmission is switched to a dynamically licensed transmission.

[0082] Increasing the number of concurrent HARQ processes can increase the burden on the UE, potentially requiring the allocation of soft buffer resources for each such process. In NR, the UE does not explicitly signal its maximum supported data rate. Instead, such information is calculated by the gNB using an equation specified in 3GPP TS 38.306 v16.0.0 “User Equipment (UE) Radio Access Capabilities (Revision 16)” (hereinafter referred to as “TS 38.306”). This equation applies to both uplink and downlink transmissions:

[0083]

[0084] For a detailed explanation of all parameters in equation (8), see Clause 4.1.2 of TS 38.306. Each individual UE capability is explicitly notified to the gNB. For example, the UE uses the maxNumberMIMO-LayersPDSCH information element to signal its access to a specific number of downlink spatial multiplexing layers. Similarly, the UE uses the supportedModulationOrderDL information element to signal its preference for the downlink modulation scheme. Support is provided. The aggregate transmission bandwidth configuration and the maximum number of component carriers supported by the UE can be signaled via the ca-BandwidthClassDL-NR information element. When configuring and scheduling the UE, the network can respect the UE radio access capability parameters signaled by the UE.

[0085] When scheduling the UE, for example for downlink transmission, the PDSCH transport block considered for transmission can be segmented into multiple code blocks according to the rules shown in the rate matching discussion above. The code blocks are then passed to the LDPC encoder for channel coding. The output of the channel coding is forwarded to the rate matching function. The rate matching function processes each channel-coded segment separately. Rate matching is performed in two phases: bit selection and bit interleaving. Soft buffer management can be significantly affected by the bit selection phase. Bit selection reduces the number of channel-coded bits to match the capacity of the allocated air interface physical resources and the UE's memory capacity. For each code block, bit selection forms a circular buffer and sets its size according to the rules briefly described in the rate matching discussion above, see Clause 5.4.2 of TS 38.212. The network uses Equation (8) and the capability parameters reported individually by the UE to calculate the approximate maximum data rate. The network assumes that the UE has sufficient memory to handle the maximum concurrent HARQ processes supported in the NR, i.e., 16 HARQ processes at the maximum supported data rate calculated above. However, in the PDSCH-ServingCellConfig RRC message, the gNB can configure the maximum number of HARQ processes for the UE using the parameter nrofHARQ-ProcessesForPDSCH, which can take values ​​of 2, 4, 6, 10, 12, and 16. If no UE is configured, the default value of 8 is assumed for the maximum number of HARQ processes.

[0086] In an NTN, the gNB might decide to configure a number of UEs greater than 16, such as 32, or even 64 or more, as the maximum number of HARQ processes. In this case, the circular buffer size setting can take into account the limitations of the UE soft buffer size. In one embodiment, a scaling factor is calculated by the base station and the UE based on the configured maximum HARQ process number, and the scaling factor is applied to the size of the circular buffer, as shown below.

[0087] Bit selection begins by writing the group of N bits belonging to a specific channel-coded segment into the circular buffer. The size of the circular buffer is calculated based on the Finite Buffer Rate Matching (LBRM). The LBRM can use the circular buffer size given by the following formula:

[0088] N cb =min(N, N) ref (9)

[0089] Where N ref The settings are as follows:

[0090] If nrofHARQ-ProcessesForPDSCH>16

[0091]

[0092] Else

[0093] α=1

[0094] End if

[0095]

[0096] In this context, TBS LBRM C and R LBR M is defined in the discussion of rate matching above and in Clause 5.4.2 of TS 38.212. Both the gNB and the UE can calculate α independently and separately using their own information.

[0097] In some embodiments, the UE may carry available soft buffer capacity (e.g., it may utilize unused soft buffer capacity if other aspects of the UE's configuration (e.g., the UE's configuration for some component carriers (CCs) result in unused soft buffer capacity) to support And there is no discount factor α, or the discount factor α is close to 1. From N in equation (2) ref The calculation of the data rate in equation (8) shows that the main factors affecting the soft buffer size are the number of component carriers, bandwidth, number of layers, and modulation order. Because the UE declares this information through UE capability signaling, the network can implicitly calculate the total available soft buffer size for the UE.

[0098] UE capability signaling refers to the mechanism by which a UE notifies the gNB of its ability to support certain functions. The following is a (non-restrictive) list of possible ways to report UE capabilities.

[0099] A UE can report its ability to perform certain functions under any circumstances. In this case, it is assumed that the UE reports its capabilities on a per-UE basis.

[0100] A UE can report its ability to perform certain features in a specific frequency band. In this case, it is assumed that the UE reports its capabilities on a per-frequency-band basis.

[0101] The UE can report its ability to perform specific features in a specific frequency band combination within a CA. In this case, it is assumed that the UE reports its capabilities based on each frequency band combination or each BC.

[0102] A UE can report its ability to perform certain features in a specific frequency band for a specific combination of frequency bands used for carrier aggregation (CA). In this case, a mechanism called feature sets can be used to allow this flexibility in reporting, and it is assumed that in this case, the UE reports its capabilities based on each feature set or each FS.

[0103] A UE can report its ability to perform specific features in a specific component carrier (CC) within a specific frequency band combination of a CA. In this case, a mechanism known as a feature set per CC can be used to allow this flexibility in reporting, and it is assumed that in this case, the UE reports its capabilities based on each feature set per CC or each FSPC.

[0104] Above, a band combination is a set of frequency bands to represent a CA configuration as described in 3GPP specification 38.101. In the list of possible ways to report UE capabilities above, the flexibility of the UE claim to support certain features increases from the beginning to the end of the list. Then, in a manner similar to equation (8), the reference soft buffer size can be calculated for each band or band combination supported by the UE claim, as follows:

[0105]

[0106] For the j-th CC,

[0107] This is the maximum number of layers supported;

[0108] It is the maximum modulation order supported;

[0109] It is the maximum RB allocation in the bandwidth BW(j) with digital μ, as defined in 5.3 of 3GPP TS 38.101-1 v16.3.0 "User Equipment (UE) Radio Transmission and Reception; Part 1: Range 1 Independent (Revision 16)"; and in 5.3 of 3GPP TS 38.101-2 v16.4.0 "User Equipment (UE) Radio Transmission and Reception; Part 2: Range 2 Independent (Revision 16)", where BW(j) is the maximum bandwidth supported by the UE in a given frequency band or combination of frequency bands;

[0110] f (j) It is a scaling factor, less than 1, which can be considered as reducing the processing burden on the UE; and

[0111] OH (j) It's an expense.

[0112] In equation (10) above, 16 represents the number of HARQ processes that the UE needs to support in the current specification, and in a specific embodiment, f (j） and OH (j) It can be removed from the equation. Equation (10) is intended to show N. soft The dependence on the variables shown in equation (10); and the above N softIt is not the absolute number of soft bits that the UE needs to support; it only represents a relative quantity. Since N can be calculated for each frequency band or combination of frequency bands supported by the UE. soft Therefore, N can also be found. soft The maximum value, and such a maximum value can be considered as N. soft，max Reference value for the size of the soft buffer.

[0113] When a UE is configured with a frequency band or combination of frequency bands that includes component carriers in which NTN operation occurs, the current buffer requirements for all component carriers other than the NTN carrier can be calculated.

[0114]

[0115] For the j-th CC among the J CCs that are not configured to run in NTN:

[0116] N can be compared with equation (4) info The value of v in the calculation is the same;

[0117] N can be compared with equation (4) info Q in the calculation m same;

[0118] N can be compared with equation (4) info n in the calculation PRB，LBRM same;

[0119] f (j) It is a scaling factor, less than 1, which can be considered as reducing the processing burden on the UE;

[0120] OH (j) It is an expense; and

[0121] In a particular embodiment, f (j) and OH (j) It can be removed from the equation.

[0122] Then, the amount of soft buffer available for NTN can be calculated as N. soft ·N soft，act To obtain the number of HARQ processes in NTN, you can calculate the parameter. Used for NTN. This value represents the amount of soft buffer for each HARQ process. Then, if there is only one NTN component carrier, N is calculated according to equation (12) below. HARQ It is the number of NTN HARQ processes, which can be stored without using a discount factor α.

[0123]

[0124] If a discount factor α is introduced, it is also possible to store values ​​greater than N. HARQ The number N of HARQ processes HARQ，α N HARQ，α It can be calculated as:

[0125]

[0126] If there is more than one NTN component carrier, the above method can be extended. In this case, further distribution rules among the NTN component carriers can be considered. Finally, for J component carriers of NTN operation, a set of N components satisfying the constraints of the following equation (14) is found. HARQ，j value.

[0127]

[0128] Because of the calculation of N in equation (4) info Similarly, the methods described in equations (10) to (14) can also be used in equation (2) for N. ref Calculated TBS LBRM and R LBRM To express.

[0129] Figure 4 A method according to some embodiments is illustrated. The method includes: at 405, a user equipment (UE) receiving first downlink control information (DCI) via a time slot of a frame, the first DCI including a first hybrid automatic repeat request (HARQ) process indicator; at 410, calculating a first HARQ process number based on a first HARQ process ID and the time slot position of the first DCI in the frame; and at 415, receiving and decoding a first data block via a HARQ process associated with the first HARQ process number. Figure 5 A system is illustrated comprising a UE 505 and a gNB 510 communicating with each other. The UE may include a radio device 515 and processing circuitry (or means for processing) 520, which can perform the various methods disclosed herein, such as... Figure 4 The method is illustrated. For example, the processing circuit 520 can receive transmissions from the gNB 510 via the radio device 515, and the processing circuit 520 can send signals to the gNB 510 via the radio device 515.

[0130] As used herein, “part of something” means “at least some of that thing,” and therefore may mean less than or all of that thing. Thus, “part of something” includes the whole thing as a special case, an example where the whole thing is part of something. As used herein, the term “or” should be interpreted as “and / or,” for example, “A or B” means either “A” or “B” or “A and B”.

[0131] Each of the terms “processing circuit” and “means for processing” is used herein to refer to any combination of hardware, firmware, and software for processing data or digital signals. Processing circuit hardware may include, for example, application-specific integrated circuits (ASICs), general-purpose or special-purpose central processing units (CPUs), digital signal processors (DSPs), graphics processing units (GPUs), and programmable logic devices, such as field-programmable gate arrays (FPGAs). In the processing circuitry used herein, each function is either performed by hardware configured to perform that function (i.e., hardwired) or by more general-purpose hardware (e.g., a CPU) configured to execute instructions stored in a non-transitory storage medium. Processing circuitry may be fabricated on a single printed circuit board (PCB) or distributed across several interconnected PCBs. Processing circuitry may include other processing circuitry; for example, processing circuitry may include two processing circuits, an FPGA and a CPU, interconnected on a PCB. As described above, the processing circuitry or means for processing in the UE may perform the methods described herein, for example, by transmitting messages (via the UE's radio equipment) or by receiving messages (via the UE's radio equipment), and in some cases, by performing further processing.

[0132] As used herein, when a method (e.g., adjustment) or a first quantity (e.g., a first variable) is referred to as “based on” a second quantity (e.g., a second variable), it means that the second quantity is an input to the method or affects the first quantity. For example, the second quantity may be an input to a function that computes the first quantity (e.g., a unique input, or one of several inputs), or the first quantity may be equal to the second quantity, or the first quantity may be the same as the second quantity (e.g., stored in one or more of the same locations in memory).

[0133] It should be understood that although the terms "first," "second," "third," etc., are used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the spirit and scope of the inventive concept, the first element, component, region, layer, or portion discussed herein may be referred to as the second element, component, region, layer, or portion.

[0134] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the concept of the invention. As used herein, the terms “substantially,” “approximately,” and similar terms are used as approximate terms rather than terms of degree and are intended to account for inherent deviations in measurements or calculations that will be recognized by those skilled in the art.

[0135] As used herein, the singular forms “a” and “an” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that, when used herein, the terms “comprising” and / or “including” specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Using expressions such as “at least one” before a list of elements modifies the entire list of elements without modifying any individual element in the list. Furthermore, when describing embodiments of the inventive concept, the use of “may” means “one or more embodiments of this disclosure.” Additionally, the term “exemplary” is intended to indicate or illustrate. As used herein, the terms “use,” “in use,” and “utilizing” may be considered synonymous with the terms “utilizing,” “being utilized,” and “exploited,” respectively.

[0136] Any numerical range described herein is intended to include all subranges containing the same numerical precision within the stated range. For example, the range “1.0 to 10.0” or “between 1.0 and 10.0” is intended to include all subranges between the minimum value of 1.0 and the maximum value of 10.0 (and inclusive), i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, while any minimum numerical limit described herein is intended to include all higher numerical limits contained therein.

[0137] Although exemplary embodiments of systems and methods for HARQ process identification and soft buffer management for non-terrestrial networks have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Therefore, it should be understood that systems and methods for HARQ process identification and soft buffer management for non-terrestrial networks constructed in accordance with the principles of this disclosure may be implemented in ways other than those specifically described herein. The invention is also defined in the following claims and their equivalents.

Claims

1. A method for identifying Hybrid Automatic Repeat Request (HARQ) processes and managing soft buffers in non-terrestrial networks, comprising: The user equipment (UE) receives a first downlink control information (DCI), which includes a first hybrid automatic repeat request (HARQ) process identifier (ID). A first HARQ process number is calculated based on a first HARQ process ID and a first timeslot number of the timeslot in which the first DCI is received. The calculation includes allocating one or more first bits of the first HARQ process ID as one or more first bits of the first HARQ process number, and allocating one or more second bits of the first timeslot number as one or more second bits of the first HARQ process number. The first data block is processed via the HARQ process associated with the first HARQ process number.

2. The method according to claim 1, wherein processing of the first data block includes encoding and transmitting the first data block.

3. The method according to claim 1, wherein processing of the first data block includes receiving and decoding the first data block.

4. The method of claim 3, further comprising: Determine the integrity of the first data block; as well as Send an ACK or NACK based on the integrity of the first data block.

5. The method of claim 3, further comprising: The UE receives a second DCI, which includes a second HARQ process ID; The second HARQ process ID is calculated based on the second HARQ process ID and the second time slot number associated with the second DCI. Determine that the second HARQ process number is equal to the first HARQ process number; The second data block is received via the HARQ process associated with the second HARQ process number; as well as Use the second data block to decode the first data block.

6. The method of claim 1, wherein calculating the first HARQ process number comprises: Reset N at the first radio frame boundary c Bit counter; In K s During each radio frame, N increments once per time slot. c Bit counter, K s It is an integer greater than 0; and N c The value of the bit counter is combined with the first HARQ process ID to form the first HARQ process number.

7. The method according to claim 6, wherein, K s It is the smallest positive integer that satisfies the following: in It is the number of time slots per frame for the subcarrier spacing configuration μ.

8. The method according to claim 1, wherein: One or more most significant bits of the first HARQ process number are one or more first bits of the first HARQ ID, and One or more least significant bits of the first HARQ process number are one or more second bits of the first timeslot number.

9. The method of claim 1, further comprising storing the first data block in a circular buffer, the circular buffer having a size of , in: N HARQ It is the number of HARQ processes occurring simultaneously. N soft It is an estimate of the total soft buffer size available within the UE for each frequency band or combination of frequency bands supported by the UE, and N soft,act This is a soft buffer requirement for all component carriers, except for NTN carriers.

10. The method of claim 1, further comprising storing the first data block in a soft buffer, the soft buffer being of size [missing information]. A cyclic buffer within 20% of its capacity. in: This is the reference buffer size used for ground links. It is the transport block size. It is a finite buffer rate matching the LBRM default bitrate value. It is the number of code blocks in the transport block, and α equals the ratio of 16 to the number of HARQ processes in PDSCH.

11. A system for identifying and managing Hybrid Automatic Repeat Request (HARQ) processes and soft buffers in non-terrestrial networks, comprising: User equipment (UE), the UE including: Radio equipment; and Processing circuit, The processing circuit is configured as follows: Receive first downlink control information (DCI), the first DCI including a first hybrid automatic repeat request (HARQ) process identifier (ID); A first HARQ process number is calculated based on a first HARQ process ID and a first timeslot number of the timeslot in which the first DCI is received. The calculation includes allocating one or more first bits of the first HARQ process ID as one or more first bits of the first HARQ process number, and allocating one or more second bits of the first timeslot number as one or more second bits of the first HARQ process number. The first data block is processed via the HARQ process associated with the first HARQ process number.

12. The system according to claim 11, wherein, The processing circuit is also configured to encode and transmit the first data block.

13. The system according to claim 11, wherein, The processing circuit is also configured to receive and decode the first data block.

14. The system according to claim 13, wherein, The processing circuit is further configured to: Determine the integrity of the first data block, and Send an ACK or NACK based on the integrity of the first data block.

15. The system according to claim 11, wherein, The processing circuit is further configured to: Receive the second DCI, which includes the second HARQ process ID; The second HARQ process ID is calculated based on the second HARQ process ID and the second time slot number associated with the second DCI. Determine that the second HARQ process number is equal to the first HARQ process number; The second data block is received via the HARQ process associated with the second HARQ process number; and Use the second data block to decode the first data block.

16. The system according to claim 11, wherein, The processing circuit is further configured to: Reset N at the first radio frame boundary c Bit counter; In K s During each radio frame, N increments once per time slot. c Bit counter, K s It is an integer greater than 0; and N c The value of the bit counter is combined with the first HARQ process ID to form the first HARQ process number.

17. The system according to claim 16, wherein, K s It is the smallest positive integer that satisfies the following: in It is the number of time slots per frame for the subcarrier spacing configuration μ.

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