Transceiver and corresponding method

Abstract

The transceiver includes one or more HARQ entities; here, the transceiver is configured to send a first data part (to another transceiver) in a first time slot by using a direct link, and use one or more HARQ entities to receive a corresponding feedback part (indicating correct or incorrect reception of the first data part) in a first subsequent time slot (one or more time slots after the first time slot) within a resource pool; the one or more HARQ entities are configured to determine the number of HARQ processes used to communicate with another direct link transceiver based on transmission parameters.

Description

Technical Field

[0001] Embodiments of the present invention relate to a transceiver comprising one or more HARQ entities, a UE comprising such a transceiver, and a method for determining the number of HARQ processes. A preferred embodiment relates to a concept called V2X maximum number of HARQ processes determination. Another embodiment relates to a transceiver comprising one or more HARQ entities. Background Art

[0002] Figures 9(a) and 9(b) are schematic diagrams of an example of a terrestrial wireless network 100, as shown in Figure 9(a), including a core network 102 and one or more radio access networks RAN1, RAN2, ...RANN. Figure 9(b) is a schematic representation of an example of a radio access network RANn that may include one or more base stations gNB1 to gNB5, each base station serving a specific area around the base station schematically represented by a corresponding cell 1061 to 1065. The base station is provided to serve users within the cell. One or more base stations can provide services to users in licensed and / or unlicensed frequency bands. The term base station, BS, refers to a gNB in ​​a 5G network, an eNB in ​​UMTS / LTE / LTE-A / LTE-APro, or a BS in other mobile communication standards. The user can be a fixed device or a mobile device. The wireless communication system can also be accessed by mobile or fixed IoT devices connected to the base station or the user. Mobile devices or IoT devices may include physical devices, ground vehicles such as robots or cars, aerial vehicles such as manned or unmanned aerial vehicles (UAVs), the latter also referred to as drones, buildings and other items or devices, which have embedded electronics, software, sensors, actuators, etc., and network connections that enable these devices to collect and exchange data over existing network infrastructure. FIG9( b) shows an exemplary view of five cells, however, a RANn may include more or fewer such cells, and a RANn may also include only one base station. FIG9( b) shows two users UE1 and UE2, also referred to as user equipment UEs, which are in cell 1062 and served by base station gNB2. Another user UE3 is shown in cell 1064 served by base station gNB4. Arrows 1081, 1082 and 1083 schematically represent uplink / downlink connections for transmitting data from users UE1, UE2 and UE3 to base stations gNB2, gNB4 or for transmitting data from base stations gNB2, gNB4 to users UE1, UE2, UE3. This can be done in a licensed band or an unlicensed band. In addition, Figure 9(b) shows two IoT devices 1101 and 1102 in cell 1064, which can be fixed or mobile devices. IoT device 1101 accesses the wireless communication system via base station gNB4 to receive and send data, as schematically represented by arrow 1121. IoT device 1102 accesses the wireless communication system via user UE3, as schematically represented by arrow 1122. The corresponding base stations gNB1 to gNB5 can be connected to the core network 102, for example via the S1 interface, via corresponding backhaul links 1141 to 1145, which are schematically represented in Figure 9(b) by arrows pointing to "core". The core network 102 can be connected to one or more external networks.In addition, some or all of the corresponding base stations gNB1 to gNB5 can be connected to each other via respective backhaul links 1161 to 1165, for example via S1 or X2 interfaces or XN interfaces in NR, schematically represented by arrows pointing to "gNBs" in Figure 9(b). Direct link channels allow direct communication between UEs, also known as device-to-device (D2D) communication. The direct link interface in 3GPP is named PC5.

[0003] For data transmission, a physical resource grid may be used. The physical resource grid may include a set of resource elements to which various physical channels and physical signals are mapped. For example, the physical channels may include physical downlink, uplink and direct link shared channels (PDSCH, PUSCH, PSSCH) carrying user specific data, also referred to as downlink, uplink and direct link payload data, a physical broadcast channel (PBCH) carrying, for example, one or more of a master information block (MIB) and a system information block (SIB), and physical downlink, uplink and direct link control channels (PDCCH, PUCCH, PSCCH) carrying, for example, downlink control information (DCI), uplink control information (UCI) and direct link control information (SCI). Note that the direct link interface may support 2 segments of SCI. This refers to a first control region containing some portion of the SCI and, optionally, a second control region containing a second portion of the control information.

[0004] For the uplink, the physical channel may further include a physical random access channel (PRACH or RACH), which the UE uses to access the network once it is synchronized and has obtained the MIB and SIB. Physical signals may include reference signals or symbols (RS), synchronization signals, etc. The resource grid may include frames or radio frames with a specific duration in the time domain and a given bandwidth in the frequency domain. A frame may have a certain number of subframes of a predetermined length (e.g., 1 millisecond). Each subframe may include 12 or 14 OFDM symbols of one or more time slots, depending on the cyclic prefix (CP) length. The frame may also include a smaller number of OFDM symbols, for example, when utilizing a shortened transmission time interval (sTTI) or a micro-slot / non-slot based frame structure that includes only a few OFDM symbols.

[0005] The wireless communication system may be any single frequency or multi-carrier system using frequency division multiplexing, such as an orthogonal frequency division multiplexing (OFDM) system, an orthogonal frequency division multiple access (OFDMA) system, or any other IFFT-based signal with or without CP, such as DFT-s-OFDM. Other waveforms, such as non-orthogonal waveforms for multiple access, such as filter bank multi-carrier (FBMC), generalized frequency division multiplexing (GFDM), or universal filter multi-carrier (UFMC) may be used. The wireless communication system may operate, for example, according to the LTE-Advanced pro standard or the 5G or NR (new air interface) standard or the NR-U (new air interface in unlicensed bands) standard.

[0006] The wireless network or communication system depicted in Figures 9(a) and 9(b) may be a heterogeneous network having different coverage networks, such as a network of macro cells, each macro cell including a macro base station such as base stations gNB1 to gNB5, and a network of small cells, each cell including a base station such as a femto base station or a pico base station (not shown in Figures 9(a) and 9(b)).

[0007] In addition to the above-mentioned terrestrial wireless networks, there are also non-terrestrial wireless communication networks (NTNs), including space-borne transceivers, such as satellites, and / or airborne transceivers, such as unmanned aircraft systems. Non-terrestrial wireless communication networks or systems can operate in a similar manner to the terrestrial systems described above with reference to Figures 9(a) and 9(b), for example according to the LTE-Advanced Pro standard or the 5G or NR (New Radio) standard.

[0008] It should be noted that the information in the above section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0009] In Rel.16 V2X, HARQ is introduced to support feedback on the direct link SL channel of device-to-device unicast transmission. Here, each UE maintains multiple HARQ processes.

[0010] For direct link communication, there are different approaches, for example, all attributes of the direct link may be preconfigured, for example, by the base station, or the user equipment has limited freedom to select the corresponding attributes. The same applies to the HARQ process to be performed by the corresponding UE communicating via the direct link.

[0011] The object of the present invention is to provide a concept capable of improving the HARQ process of a direct link.

[0012] This object is solved by the subject-matter of the independent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the present invention will now be discussed with reference to the accompanying drawings, in which

[0014] Figure 1 shows a schematic block diagram of a transceiver, such as a transceiver of a user equipment having one or more HARQ entities according to a basic embodiment;

[0015] Figure 2 A schematic diagram illustrating the relationship between HARQ RTT (round trip time) and the number of HARQ processes is shown;

[0016] Figure 3 A schematic diagram for illustrating a PSFCH period and a feedback period equal to (0, 1, 2, 4) time slots configured by periodPSFCHresource according to an embodiment is shown;

[0017] Figure 4 Schematically illustrates communication between two senders and one receiver by using direct link communication according to an embodiment;

[0018] Figure 5 Schematically shows the minimum time gap between the PSFCH and the associated PSSCH in a time slot;

[0019] Figure 6 Schematically illustrates the maximum SL round trip time and the resulting high process according to an embodiment;

[0020] Figure 7 Schematically illustrates the SL round trip time of a PSFCH with a minimum time gap of 2 and a periodicity of 1 according to an embodiment;

[0021] FIG8( a ) and FIG8( b ) schematically illustrate obfuscated data according to an embodiment;

[0022] Figures 9(a) and 9(b) schematically show representations of examples of terrestrial wireless networks; and

[0023] Fig.10 A schematic diagram of a representation of a computer system is shown. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be discussed in detail with reference to the accompanying drawings, wherein similar or identical reference numerals are provided to options having similar or identical functions so that their descriptions are mutually applicable and interchangeable.

[0025] In reference Figure 1 Before discussing the method according to the embodiment in detail, the problems and proposed solutions according to the basic embodiment will be discussed.

[0026] As mentioned before, HARQ has been introduced to support feedback for device-to-device unicast transmissions on direct link channels. The UE maintains multiple HARQ processes. Incoming transmissions in a time slot are assigned to a HARQ process. For this purpose, each direct link control information (SCI) contains a HARQ process ID that identifies to which HARQ process this particular data transmission via the physical direct link shared channel (PSSCH) belongs. Due to the fact that a UE will not send more than one PSSCH to the same UE in a given time slot, the number of HARQ processes required is determined by the HARQ round trip time (RTT) and the (success or) failure of the transmission of a particular data, see Figure 1 By using a HARQ entity that performs determination of the number of HARQ processes, the number of HARQ processes may be dynamically adjusted.

[0027] According to an embodiment, the MAC entity includes at most one direct link HARQ entity for transmission on SL-SCH, which maintains multiple parallel direct link processes.

[0028] Transceiver and UE

[0029] According to a basic implementation, a transceiver including one or more HARQ entities is used. The transceiver is configured to send a first data portion (to another transceiver) in a first time slot by using a direct link and receive a corresponding feedback portion (indicating correct or incorrect reception of the first data portion) in a first subsequent time slot (one or more time slots after the first time slot) using the HARQ entity in a resource pool. Here, the one or more HARQ entities are configured to determine the number of HARQ processes used to communicate with another direct link transceiver based on transmission parameters.

[0030] According to an embodiment, one or more source ids, destination ids, and / or broadcast types (eg, unicast or multicast) are used to identify communications with another direct link transceiver.

[0031] According to an embodiment, the transmission parameters based on which the determination of the number of HARQ processes is performed may include one or more resource pool parameters, or parameters extracted from a resource pool configuration. The transmission parameters may indicate a configuration grant configuration.

[0032] According to an embodiment, the maximum number of transmitting direct link processes associated with the direct link HARQ entity may be limited, for example, may be 16. It may be considered that the direct link process is used for the transmission of multiple MAC-PDUs. For the transmission of multiple MAC-PDUs of direct link resource allocation mode 2, the maximum number of transmitting direct link processes associated with the direct link HARQ entity may be 4. This maximum number may be a resource pool parameter or a parameter extracted from the resource pool configuration.

[0033] The possible parameters are discussed below. According to an embodiment, the SL-BWP-Tool-Config field may be used to perform SR-TX pool scheduling. For example, SL-TX pool scheduling indicates that the UE is allowed to transmit resources for NR direct link communications on the configured BWP according to network scheduling. For PSFCH-related configurations, if configured, they will be used for PSFSCH transmission / reception. According to a further embodiment, the normality of SL-TX pool selection indicates that the UE is allowed to send resources for NR direct link communications on the configured BWP through UE autonomous resource selection. For PSFCH-related configurations, if configured, they will be used for PSFSCH transmission / reception. According to a further embodiment, the SL configuration authorization configuration field description may be used as follows: SL-NROFHARQ processes may be supported. This field indicates the number of HARQ processes authorized to be configured for a specific configuration. It applies to both type 1 and type 2.

[0034] Embodiments of the present invention are based on the principle that the number of HARQ entities can be determined or calculated based on known parameters for transmission, such as the feedback period or the minimum time interval between the first and subsequent time slots. Another parameter that may have an impact is the minimum time interval between the first subsequent time slot (in which the ACK / NACK can be received) and the time slot used for retransmission. The parameters discussed above determine the so-called round-trip time of the entire HARQ process. In order to ensure that each data belonging to a time slot within a complete round-trip time can be cached, the number of HARQ processes must be adapted to this round-trip time. Based on the parameters given by the resource pool configuration, the minimum time interval, the feedback processing time and the feedback period can vary. Therefore, the round-trip time and the number of (required) HARQ processes also vary. By knowing the number of required HARQ processes, the number of HARQ processes used by the HARQ entities can be dynamically adjusted.

[0035] Therefore, according to an embodiment, the transceiver performs retransmission of the first data portion in the first retransmission time slot or in the first retransmission time slot after the first subsequent time slot. According to an embodiment, the HARQ entity is configured to buffer the first data portion and / or the further data portion and / or retransmit the first data portion or the further data portion when a corresponding feedback portion indicates incorrect reception of the first data portion.

[0036] According to a further embodiment, the number of HARQ processes is determined based on the following, wherein the number of HARQ processes is determined based on the round trip time of the entire HARQ process for one data portion. The round trip time or the number of HARQ processes can therefore be determined by the following formula:

[0037] T RTT =T minRX +P PSFCH , where T minRXcorresponds to the minimum time interval between the first time slot and the first subsequent time slot and the data portion, where P PSFCH Corresponds to the feedback cycle. Alternatively, based on the formula T RTT =T minRX +P PSFCH +T feedbackprocessing , where T minRX corresponds to the minimum time interval between the first time slot and the first subsequent time slot and the data portion, where P PSFCH corresponds to the feedback cycle, where T feedbackprocessing is the minimum time interval between the first subsequent time slot and the time slot used for retransmission.

[0038] According to an embodiment, the number of data packets to be stored by the HARQ entity depends on the number of HARQ processes. According to an embodiment, the HARQ entity may be configured to determine the number of HARQ processes for identifying a data portion for communication with another direct link transceiver (e.g., S_[H-ID]=ceil(log2(N_[H-Processes])). According to an embodiment, the number of HARQ processes depends on the number of time slots between the first time slot and the first subsequent time slot.

[0039] According to an embodiment, the number of HARQ processes is limited, for example, by default to seven or eight; alternatively, the transceiver is configured to send a second data portion in a second time slot by using a direct link and receive a corresponding feedback portion in a second subsequent time slot. According to an embodiment, based on the transmission parameters, the number of HARQ processes is limited to, for example, 4 or 16.

[0040] According to an embodiment, the transceiver is configured to send a second data portion in a second time slot by using a direct link and receive a corresponding feedback portion in a second subsequent time slot. According to a further embodiment, the transceiver may be configured to send another first data portion (to another other transceiver) by using another (parallel) direct link and receive another corresponding feedback portion (indicating correct / incorrect reception of the other first data portion).

[0041] According to an embodiment, one or more HARQ entities that do not have an available HARQ process rewrite / refresh the existing HARQ process. For example, the buffer to be rewritten / refreshed is selected by one or more of the following:

[0042] - the lowest priority of the packet,

[0043] - source ID and / or target ID,

[0044] - type of propagation,

[0045] - the associated logical channel (LCH) or QoS flow,

[0046] - Age of the data portion (e.g. remove oldest first)

[0047] - remaining packet delay budget,

[0048] - Number of retransmissions,

[0049] - Buffer size, e.g. drop large packets to free up more soft buffers

[0050] - For example, a transmission with multiple retransmissions (each retransmission also occupies the soft buffer).

[0051] Another embodiment provides another transceiver, such as a receiver. This other transceiver also includes one or more HARQ entities. The other transceiver is configured to receive a first data portion in a first time slot by using a direct link (from the transceiver), and use one or more HARQ entities to send a corresponding feedback portion (indicating correct / incorrect reception of the first data portion) in a first subsequent time slot in a resource pool. Here, the one or more HARQ entities are configured to determine the number of HARQ processes used to communicate with another direct link transceiver (transmitter) based on transmission parameters.

[0052] A method for determining the number of HARQ processes for another transceiver, wherein the other transceiver is configured to receive a first data portion (from the transceiver) in a first time slot by using a direct link and to send a corresponding feedback portion (indicating correct / incorrect reception of the first data portion) in a first subsequent time slot, the method comprising the step of determining the number of HARQ processes based on transmission parameters.

[0053] The transceiver discussed above is a basic implementation. According to a further embodiment, a user equipment comprising a transceiver or another transceiver is required.

[0054] system

[0055] Another embodiment relates to a system comprising at least a transceiver as defined above and a further transceiver.

[0056] method

[0057] Another embodiment provides a method for determining the number of HARQ processes for a transceiver. The transceiver is configured to send a first data portion (to another transceiver) in a first time slot using a direct link and receive a corresponding feedback portion (indicating correct or incorrect reception of the first data portion) in a first subsequent time slot (one or more time slots after the first time slot) within a resource pool using one or more HARQ entities, wherein the method includes the step of determining the number of HARQ processes for communication with another direct link transceiver based on a transmission parameter.

[0058] Another embodiment provides a method for determining the number of HARQ processes for another transceiver. The other transceiver is configured to receive a first data portion (from the transceiver) in a first time slot by using a direct link, and send a corresponding feedback portion (indicating correct / error reception of the first data portion) in a first subsequent time slot within a resource pool using one or more HARQ entities, the method comprising the step of determining the number of HARQ processes for communication with the other direct link transceiver based on a transmission parameter.

[0059] According to a further embodiment, the method may be computer-implemented.

[0060] According to further embodiments,

[0061] Having now discussed the basic implementation according to the embodiments, further details regarding the implementation will be given with reference to the drawings.

[0062] Figure 1 Two transceivers 10a and 10b of a user equipment, for example, with a connection 15 are shown. As shown, data should be transmitted from the transceiver 10a / transmitter 10a to the transceiver 10b / receiver 10b. Here, two exemplary data packets 15a and 15b are shown. These data packets 15a and 15b are sent to the receiver 10b, where parallel HARQ processing is performed by using the HARQ entity 12a. For example, the data packets 15a, 15b can be sent continuously to each other using different times. The HARQ entity 12a may include a processor 12ap and a memory 12am for buffering the data packets 15a and 15b to be sent. Similarly, the receiver 10b includes the same entities 12bp and 12bm. The processor 12ap maps the data packets 15a and 15b to be sent to the corresponding memory portions of the memory 12am. The number of data portions to be buffered or the number of parallel HARQ processes for a transmission 15 at a time is usually preconfigured. Here, it can be equal to 8 (worst case parameter).

[0063] In order to perform this HARQ processing more dynamically so that parallel transmissions can be used for the same entity 12am without increasing its size (see Figure 4 ), the number of HARQ processes should be reduced as much as possible, for example, to the minimum number required.

[0064] Just for the sake of completeness, it should be noted that the corresponding HARQ entity, for example the HARQ entity 12b, analyzes the received data 15 to determine the correct / incorrect, complete / incomplete reception of the data 15. For example, in the case of correct reception, it sends an ACK to the transceiver 10a, wherein instead in the case of incorrect reception, it sends a NACK to the transceiver 10a. The HARQ entity 12a of the transceiver 10a receives this ACK / NACK and, for example, in the case of a NACK (negative acknowledgement), performs a retransmission of the buffered data from the memory 12m.

[0065] It has been agreed to maintain only one HARQ entity for each direct link carrier used for reception, i.e., the HARQ process is shared between the connections. When multiple transmitters occupy the HARQ process at the same time, this can lead to insufficient HARQ processes on the receiver side. In addition, the introduction of up to 32 retransmissions exacerbates this problem because the HARQ process may be occupied for a longer time. In order to alleviate these problems, one of the methods is to limit the maximum number of HARQ processes per link. As described above, the maximum number of transmitting direct link processes associated with a direct link HARQ entity can be limited to, for example, 16 or, for example, 4. According to an embodiment, the limitation can depend on different modes. For example. Mode 1 can configure up to 16 HARQ processes in the configuration authorization configuration, where M2 only supports 4 transmitting HARQ processes.

[0066] In order to determine the minimum / latest / required number of HARQ processes, the HARQ entity 12a determines the number of HARQ processes for communicating with the other direct link transceiver 12b based on the transmission parameters.

[0067] An example of these transmission parameters is the period of the corresponding reception command, i.e. the period of the ACK / NACK. This ACK / NACK can be transmitted by using a separate physical control channel or within the same channel in which the transmission 15 is or has been performed. For example, the ACK / NACK can be received within certain periodic resource parts. This period is or can be used as a parameter for determining the number of HARQ processes. This parameter can be called periodPSFCHresource. Another parameter is the minimum time interval between the transmission and the possibility for the receiver to react. For this minimum time gap, the processing performance of the receiver 10b or in particular the HARQ entity 12b of the receiver 10b and the transmission time are relevant. The background is that the analysis of the received data can only start after some time frames and also has a certain duration. This parameter is called MinTimeGapPSFCH. The two parameters MinTimeGapPSFCH and periodPSFCHresource are usually parameters defined by the RP configuration. This means that the RP configuration may include

[0068] ·periodPSFCHresource(0,1,2,4)

[0069] οPSFCH periodicity in time slots, see Figure 3

[0070] For example, Figure 3 It is shown that the periodicity is configured by periodPSFCHresources. In the first row, a period of 1 is illustrated. This means that after each PSFCH time frame, for example number 1, another time frame, for example number 2, follows, in which the PSFCH of the previous time frame is transmitted. As shown in the second row, there is at least one time frame... This means that for PSSCH number 1, the PSFCH follows in time frame number 3. For a period of 4, this principle is shown in the last column. Of course, there is also the option to enable a period of 0. Here, the PSFCH is transmitted within the same time slot.

[0071] MinTimeGapPSFCH(2,3)

[0072] ο Minimum spacing between PSSCH and corresponding PSFCH, see Figure 2 .

[0073] Figure 2 The relationship between HARQ 1 and time and the number of HARQ processes is shown. Here, the first PSSCH (#1) is shown with the minimum time interval PSFCH3 (earliest possible feedback time slot) and period 4. It can be seen that due to the periodicity, only the modified time slots are used, and here n+2 and n+6 enable PSFCH. Starting from the number 1, due to the minimum time interval and periodicity, the first feedback can be received in time slot m+6 / #7. There is also a third influencing factor, namely the processing time for retransmission. Here, there are two time slots, as shown by the erroneous new data of the retransmission.

[0074] Depending on the location of the PSSCH and the location of the periodic PSFCH, the number of HARQ processes can be reduced from n+8, for example, if the minimum time interval and the first possible PSFCH according to the periodicity fall into the same time slot. For example, when starting from PSSCH number 3, the number of HARQ processes can be reduced by 2. For PSSCH number 4, the number of HARQ processes can be reduced by 3 because the minimum time interval and the error of periodPSFCHresource point to the same time slot.

[0075] This process is of course performed for subsequent time frames PSSCH#2, PSCH#3, etc. As discussed above, for each HARQ process belonging to the corresponding PSSCH, the number can vary. Therefore, the number of processes can be adjusted dynamically.

[0076] This information may be extracted from the RP configuration. Here, a mapping of the number of HARQ processes, i.e. the number of bits in the SCI for the HARQ process RD, to the RP configuration may be performed. For example, this may be done based on the HARQ RTT (Round Trip Time).

[0077] HARQRTT is determined by the following formula:

[0078] T RTT =MinTimeGapPSFCH+periodPSFCHresource+FeedbackProcessing,

[0079] The first two parameters are given in the RP configuration, and FeedbackProcessing can be implicitly assumed by the BS to be a certain value, or pre-configured or explicitly configured by the BS.

[0080] The number of HARQ processes required is equal to the HARQ RTT, so

[0081] T HARQprocesses =T RTT .

[0082] According to an embodiment, the number of (required) HARQ processes depends on their resource pool configuration. Here, the resource pool configuration may be provided by the BS (Base Station), for example. The resource pools are defined within the direct link carrier.

[0083] According to another option, the round trip time can be calculated as follows:

[0084] T RTT =T minRX +P PSFCH

[0085] Among them, T minRX Corresponds to the minimum time interval between PSSCH and PSFCH (MinTimeGapPSFCH). PSFCH Corresponding to the PSFCH feedback resource period (periodPSFCHresource).

[0086] When the round trip time is calculated based on one of the above formulas, the number of HARQ processes can be determined. Here, the round trip time can be calculated by unit time slots, where each time slot requires a HARQ process, i.e., a memory for buffering data. For example, in the case where less than or equal to 4 HARQ processes are required, it is sufficient to use two bits as the HARQ process ID in the SCI. If 5-8 HARQ processes are required, three bits are sufficient, and so on.

[0087] In addition, the maximum number of HARQ processes can be configured to 2 N , where N is 1, 2, 3, or 4. When the round-trip time is short, not all HARQ processes may be used or before scheduling retransmissions, and the transmitter can use the remaining available HARQ processes for new data, thereby gaining greater scheduling freedom.

[0088] From here, the implementation might look like this:

[0089] Use a different second-stage SCI format

[0090] To avoid wasting bits, different second-stage SCI formats may be used, and in each SCI format, the HARQ process ID parameter may correspond to each N value.

[0091] Use the same Phase II SCI format

[0092] The maximum value of N is used for the HARQ process ID parameter. The remaining bits can be used in one of the following ways:

[0093] o fill unused bits,

[0094] ο not utilizing the full value range,

[0095] o Using too many HARQ processes for higher priority transmissions.

[0096] In the following, some examples will be given of the number of required HARQ processes depending on the corresponding parameters.

[0097] This results in a maximum round trip time of

[0098] T RTT_max =3 time slots + 4 time slots = 7 time slots,

[0099] When MinTimeGapPSFCH of 3 time slots and periodPSFCHresource of 4 time slots are used, the maximum number of HARQ processes required is 7.

[0100] Figure 6 This configuration is shown where the initial transmission of PSSCH with HARQ process number 1 happens to be missing the PSFCH in slot n+2. Therefore, feedback is sent in slot n+6, allowing the process to be reused in slot n+7.

[0101] UE reuse can be, for example, for new transmissions, such as when positive feedback is received via PSFCH in time slot n+6, or for retransmissions. Here, dynamic adaptation of subsequent HARQ processes for PSSCH #2, #3, #4, #5, #6, #7 can be performed as the dynamic adaptation discussed above, reducing the overall processing requirements.

[0102] Since the HARQ process number is represented in N bits in the DCI, a value of 2^N should be chosen. Therefore, a suitable candidate for the maximum number of HARQ processes is 8, at least for this embodiment. According to an embodiment, a maximum of 7 HARQ processes are sufficient.

[0103] Therefore, by default, 7 HARQ processors or 8 HARQ processes may be set.

[0104] Similarly, we can calculate the minimum round trip time and the number of HARQ processes required. This leads to the minimum round trip time

[0105] T RTT_max = 2 time slots + 1 time slot = 3 time slots,

[0106] When using MinTimeGapPSFCH of 2 time slots and periodPSFCHresource of 1 time slot. Figure 7 This configuration is shown. Therefore, the minimum required number of HARQ processes is 3.

[0107] Since the period in each frame n, n+1, n+2, n+3 is 1, the PSFCH resources are shown. It should be noted that the PSFCH resource of, for example, n+0 is arranged in the subsequent time slot, namely n+1. The error minimum time interval PSFCH equal to 2 indicates that at least two time slots must be between the PSSCH and the corresponding PSFCH resource. In this embodiment, this leads to a minimum of 4 HARQ processes per connection, N=2 bits. Observation 3: A minimum of 3 HARQ processes are required per connection.

[0108] Based on the above analysis, we recommend that the maximum number of HARQ processes per connection should be limited to 8. Based on the parameters defined in the resource pool, the number of HARQ processes can also be limited to 4.

[0109] Therefore, according to an embodiment, the maximum number of HARQ processes 28 per connection may be limited. According to a further embodiment, the number of HARQ processors 24 may be limited when resource pool parameters allow, ie when dynamic determination of HARQ processes is enabled.

[0110] Based on this analysis performed in this paper, the following observations and conclusions can be drawn. These conclusions can be set as bounds for determining the number of HARQ processors discussed above.

[0111] Observation 1: The number of required HARQ processes depends on the resource pool configuration.

[0112] Observation 2: A maximum of 7 HARQ processes per connection is sufficient.

[0113] Observation 3: Each connection requires at least 3 HARQ processes.

[0114] Based on our observations, we make the following recommendations:

[0115] Limit the maximum number of HARQ processes to 8 per connection.

[0116] Limit the number of HARQ processes to 4 if resource pool parameters allow.

[0117] According to an embodiment, the HARQ entity may activate a dynamic determination / adaptation of the number of HARQ processes. This activation signal may be received as part of resource pool parameters and / or as RRC signaling (Radio Resource Control signaling) from the BS.

[0118] SL resource pool RRC configuration: This is the RRC configuration to be added to TS38.331 in the current draft. Figure 8(a) and 8(b) , an exemplary RRC configuration is shown. Reference symbol HARQ Enable is marked, and Enable indicates the use of a new information element that activates a known process that is dynamically determined.

[0119] Note that the above principle, for example in Figure 1 The principles discussed in the context of generally refer to one direct link communication, e.g., between two transceivers of two UEs. Typically, but not necessarily, one HARQ entity per direct link carrier is used. Of course, one HARQ entity can be shared by multiple direct link communications performed by one transceiver in the same direct link carrier. This Figure 4 shown.

[0120] Figure 4 Three transceivers 10a, 10b and 10c are shown, each having a HARQ entity 12am, 12bm, 12cm and HARQ process mappings 12ap, 12bp and 12cp.The receiver 10b receives direct link communications 15_1, 15_2 from two transmitters 10a and 10c.

[0121] Thus, one transceiver 10b, here a receiver, can establish multiple direct link communications 15_1 and 15_2. This receiver 10b comprises at least one HARQ entity, which is shared by the two communications 15_1 and 15_2.

[0122] Of course, dynamic adaptation can be performed for both transmit processors.

[0123] According to a further embodiment, two HARQ entities may be used for the two transmissions 15_1 and 15_2.

[0124] In a further embodiment, the use of dynamicHARQprocessNumberDetermination may be negotiated directly between SL transceivers during PC5 connection establishment.

[0125] In multicast, the group leader can instruct the use of this function.

[0126] According to an embodiment, the user equipment UE can be a mobile terminal, or a fixed terminal, or a cellular IoT-UE, or a vehicle-mounted UE, or a vehicle-mounted group leader (GL) UE, or IoT, or a narrowband IoT, NB-IoT, device or WiFi non-access point station, non-AP STA, such as 802.11ax or 802.11be, or a ground-based vehicle, an aircraft or an unmanned aircraft, or a mobile base station, or a roadside unit, or a building, or any other item or device provided with network connectivity that enables the item or device to communicate using a wireless communication network, such as a sensor or actuator, or any other item or one or more of the devices provided with network connectivity, enabling the item / device to communicate using a direct link of the wireless communication network, such as a sensor or actuator, or any network entity with direct link capability. The base station BS can be implemented as a mobile or non-mobile base station, and can be a macrocell base station or a small cell base station, or a central unit of a base station, or a distributed unit of a base station, or a roadside unit, or a UE, or a group leader (GL), or a relay, or a remote radio head, or an AMF, or an SMF, or a core network entity, or a mobile edge computing entity or a network slice in an NR or 5G core environment, or a WiFi AP STA, such as 802.11ax or 802.11be, or any one or more of the sending / receiving points TRP that enable an item or device to communicate using a wireless communication network, so that an item or device with network connectivity can use the wireless communication network to communicate.

[0127] Although certain aspects of the described concepts have been described in the context of an apparatus, it is apparent that these aspects also represent a description of a corresponding method, where a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.

[0128] The various elements and features of the present invention can be implemented in hardware using analog and / or digital circuits, in software by executing instructions by one or more general or special processors, or as a combination of hardware and software. For example, embodiments of the present invention can be implemented in the environment of a computer system or another processing system. Fig.10 An example of a computer system 500 is shown. The units or modules and the steps of the methods performed by these units can be executed on one or more computer systems 500. The computer system 500 includes one or more processors 502, such as a dedicated or general-purpose digital signal processor. The processor 502 is connected to a communication infrastructure 504, such as a bus or a network. The computer system 500 includes a main memory 506, such as a random access memory (RAM), and an auxiliary memory 508, such as a hard drive and / or a removable storage drive. The auxiliary memory 508 can allow computer programs or other instructions to be loaded into the computer system 500. The computer system 500 can further include a communication interface 510 to allow software and data to be transmitted between the computer system 500 and external devices. The communication can be in the form of electronic, electromagnetic, optical or other signals that can be processed by the communication interface. The communication can use wires or cables, optical fibers, telephone lines, cellular phone links, RF links and other communication channels 512.

[0129] The terms "computer program medium" and "computer readable medium" are generally used to refer to tangible storage media, such as a removable storage unit or a hard disk.

[0130] Fig.10 It is a schematic diagram of a computer system.

[0131] The implementation in hardware or software can be performed using a digital storage medium, such as cloud storage, floppy disk, DVD, Blu-ray, CD, ROM, PROM, EPROM, EEPROM or flash memory, on which electronically readable control signals are stored, which cooperate (or can cooperate) with a programmable computer system to perform the corresponding method. Therefore, the digital storage medium can be computer-readable.

[0132] Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.

[0133] Generally, embodiments of the present invention can be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer.The program code may, for example, be stored on a machine readable carrier.

[0134] Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier. In other words, an embodiment of the inventive method is therefore a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

[0135] Therefore, a further embodiment of the method of the present invention is a data carrier (or a digital storage medium, or a computer-readable medium) including a computer program recorded thereon for performing one of the methods described herein. Therefore, a further embodiment of the method of the present invention is a data stream or a signal sequence representing a computer program for performing one of the methods described herein. The data stream or signal sequence can, for example, be configured to be transmitted via a data communication connection, for example, via the Internet. Further embodiments include processing means, such as a computer or a programmable logic device, which is configured to or adapted to perform one of the methods described herein. Further embodiments include a computer having a computer program for performing one of the methods described herein installed thereon.

[0136] In some embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In some embodiments, a field programmable gate array may collaborate with a microprocessor to perform one of the methods described herein. Typically, these methods are preferably performed by any hardware device.

[0137] The above embodiments are only used to illustrate the principles of the present invention. It should be understood that modifications and variations of the arrangements and details described herein will be apparent to other persons skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the appended patent claims, rather than by the specific details presented in the description and explanation of the embodiments herein.

Claims

1. A transceiver (10a, 10b), comprising one or more HARQ entities; wherein the transceiver (10a, 10b) is configured to send a first data portion in a first time slot by using a direct link (15, 15_1, 15_2) and receive a corresponding feedback portion in a first subsequent time slot in a resource pool using one or more HARQ entities; in, One or more HARQ entities are configured to determine the number of HARQ processes used for communicating with another direct link (15, 15_1, 15_2) transceiver (10a, 10b) based on transmission parameters (rp), wherein the transmission parameters (rp) include a feedback period, a minimum time interval between a first and subsequent time slots and / or time slots for retransmission.

2. The transceiver (10a, 10b) of claim 1, wherein communication with another direct link (15, 15_1, 15_2) transceiver (10a, 10b) is identified using one or more of a source id, a destination id and / or a propagation type.

3. The transceiver (10a, 10b) according to claim 1, wherein: The transfer parameters (rp) include one or more resource pool parameters, or parameters extracted from a resource pool configuration.

4. The transceiver (10a, 10b) according to claim 1, wherein: The number of HARQ processes is determined according to the round trip time of the entire HARQ process for one data portion.

5. The transceiver (10a, 10b) according to claim 1, wherein The number of HARQ processes is determined based on the following formula for the round trip time: T RTT = T minRX + P PSFCH Determine, where T minRX corresponds to the minimum time interval between the first time slot (#2) and the first subsequent time slot (n+1, n+2, n+3, n+4, n+6, n+7, n+8, n+9) where the PPSFCH corresponds to a feedback cycle; or T RTT = T minRX + P PSFCH + T feedbackprocessing , where T minRX corresponds to the minimum time interval between the first time slot (#2) and the first subsequent time slot (n+1, n+2, n+3, n+4, n+6, n+7, n+8, n+9), where P PSFCH corresponds to the feedback cycle, where T feedbackprocessing is the minimum time interval between the first subsequent time slot (n+1, n+2, n+3, n+4, n+6, n+7, n+8, n+9) and the time slot used for retransmission.

6. The transceiver (10a, 10b) according to claim 1, wherein: The one or more HARQ entities are configured to determine a number of HARQ processes for identifying a data portion for communication with another direct link transceiver (10a, 10b).

7. The transceiver (10a, 10b) according to claim 1, wherein: The number of HARQ processes depends on the number of time slots between the first time slot and the first subsequent time slot.

8. The transceiver (10a, 10b) of claim 1, wherein the number of data packets to be stored by the one or more HARQ entities depends on the number of HARQ processes.

9. The transceiver (10a, 10b) according to claim 1, wherein the number of HARQ processes is: The default limit or the default limit is seven or eight; or When dynamic determination of the number of HARQ processes based on transmission parameters (rp) is enabled, reduced to four; or limited to a minimum of three; or Based on the transmission parameter limit or limited to 4 or 16.

10. The transceiver (10a, 10b) according to claim 1, wherein One or more HARQ entities are configured as Dynamically adjust the number of HARQ processes; and / or Determination or dynamic determination of the number of activated HARQ processes; or Dynamically adjust the number of HARQ processes; and / or The determination or dynamic determination of the number of activated HARQ processes is performed by configuration or as part of resource pool configuration.

11. The transceiver (10a, 10b) according to claim 1, wherein: The one or more HARQ entities are configured to buffer the first data portion and / or the further data portion and / or to retransmit the first data portion or the further data portion in response to a corresponding feedback portion indicating erroneous reception of the first data portion.

12. The transceiver (10a, 10b) according to claim 11, wherein The retransmission of the first data portion is performed at a first retransmission time slot after the first subsequent time slot.

13. The transceiver (10a, 10b) according to claim 1, wherein: The transceiver (10a, 10b) is configured to transmit a second data portion in a second time slot by using the direct link, and receive a corresponding feedback portion in a second subsequent time slot.

14. The transceiver (10a, 10b) according to claim 1, wherein: The transceiver (10a, 10b) is configured to send another first data portion to another other transceiver (10a, 10b) by using another direct link (15, 15_1, 15_2) and receive another corresponding feedback portion indicating correct / incorrect reception of the another first data portion.

15. The transceiver (10a, 10b) of claim 1, wherein an existing HARQ process is overwritten / refreshed in case one or more HARQ entities have no available HARQ processes.

16. The transceiver (10a, 10b) according to claim 15, wherein The buffer to be rewritten / refreshed is selected by one or more of the following: - the lowest priority of the packet, - source ID and / or target ID, - type of transmission, - the associated logical channel (LCH) or QoS flow, - Age of the data part - remaining packet delay budget, - Number of retransmissions, - buffer size, - Transmission with multiple retransmissions.

17. A transceiver (10a, 10b), comprising one or more HARQ entities, wherein the transceiver (10a, 10b) is configured to receive a first data portion in a first time slot by using a direct link (15, 15_1, 15_2), and to send a corresponding feedback portion in a first subsequent time slot within a resource pool using the one or more HARQ entities, wherein the one or more HARQ entities are configured to determine the number of HARQ processes used for communicating with another direct link (15, 15_1, 15_2) transceiver (10a, 10b) based on a transmission parameter (rp) or a configuration grant configuration as part of the transmission parameter (rp); The transmission parameters (rp) include a feedback period, a minimum time interval between the first and subsequent time slots and / or time slots for retransmission.

18. The transceiver (10a, 10b) according to claim 17, wherein The one or more HARQ entities are configured to analyze the received first data portion with respect to correct / incorrect / complete / incomplete reception of the received first data portion in order to determine a corresponding feedback portion.

19. A user equipment (UE1, UE2, UE3), comprising the transceiver (10a, 10b) according to claim 1 or 17.

20. A communication system comprising at least the transceiver (10a, 10b) according to claim 1 and the transceiver (10a, 10b) according to claim 17.

21. A method for determining the number of HARQ processes of a transceiver (10a, 10b), wherein the transceiver (10a, 10b) is configured to transmit a first data portion in a first time slot by using a direct link (15, 15_1, 15_2) and receive a corresponding feedback portion in a first subsequent time slot within a resource pool using one or more HARQ entities, wherein the method comprises the steps of determining a number of HARQ processes for communicating with another direct link (15, 15_1, 15_2) transceiver (10a, 10b) based on a transmission parameter (rp); The transmission parameters (rp) include a feedback period, a minimum time interval between the first and subsequent time slots and / or time slots for retransmission.

22. A method for determining the number of HARQ processes of a transceiver (10a, 10b), wherein the transceiver (10a, 10b) is configured to receive a first data portion in a first time slot by using a direct link (15, 15_1, 15_2) and to send a corresponding feedback portion indicating correct / incorrect reception of the first data portion in a first subsequent time slot within a resource pool using one or more HARQ entities, the method comprising the steps of determining the number of HARQ processes for communicating with another direct link (15, 15_1, 15_2) transceiver (10a, 10b) based on a transmission parameter (rp); The transmission parameters (rp) include a feedback period, a minimum time interval between the first and subsequent time slots and / or time slots for retransmission.

23. A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method according to claim 21 or 22 is implemented.

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