Efficient scheduling in wireless communication systems

Abstract

Method for transmitting downlink control information in a cellular communication network using OFDM transmission format from a base station transmitting a DCI message containing at least one additional field dynamically allocating n times repetition to be applied to a transport block to be transmitted by a UE operating in the network. The additional field can be in the TDRA or be a parameter of the DCI message.

Description

Technical Field

[0001] This invention relates to scheduling communication in wireless communication systems, and more particularly to efficient scheduling of multiple transport blocks using a single downlink control indicator. Background Technology

[0002] Wireless communication systems such as third-generation (3G) mobile phone standards and technologies are well-known. These 3G standards and technologies were developed by the Third Generation Partnership Project (3GPP) (RTM). Third-generation wireless communication has been widely developed to support macrocell mobile phone communication. Communication systems and networks have evolved towards broadband and mobile systems.

[0003] In a cellular wireless communication system, User Equipment (UE) connects to the Radio Access Network (RAN) via a radio link. The RAN comprises a set of base stations and an interface to the Core Network (CN). These base stations provide radio links to UEs located in cells covered by the base stations, and the interface to the CN provides overall network control. It should be understood that the RAN and CN each perform their respective functions relevant to the overall network. For convenience, the term "cellular network" will be used to refer to the combined RAN & CN, and it should be understood that this term is used to refer to the respective systems used to perform the disclosed functions.

[0004] The 3G Partnership developed the so-called Long Term Evolution (LTE) system, also known as the Evolved Universal Mobile Telecommunication System Territorial Radio Access Network (E-UTRAN), for mobile access networks, where one or more macro cells are supported by base stations called eNodeBs or eNBs (evolved NodeBs). More recently, LTE is further evolving into the so-called 5G or NR (New Radio) system, where one or more cells are supported by base stations called gNBs. NR is proposed to use the Orthogonal Frequency Division Multiplexed (OFDM) physical transmission format.

[0005] The NR protocol is designed to provide the option to operate in unlicensed radio bands (known as NR-U). When operating in unlicensed radio bands, the gNB and UE must compete with other devices for physical media / resource access. For example, Wi-Fi (RTM), NR-U, and LAA can use the same physical resources.

[0006] The trend in wireless communication is towards providing services with lower latency and higher reliability. For example, NR aims to support Ultra-reliable and low-latency communications (URLLC), while Machine-Type Communications (mMTC) aims to provide low latency and high reliability for small packet sizes (typically 32 bytes). A user plane latency of 1ms with a reliability of 99.99999% is proposed, and a 10... -5 Or 10 -6 The packet loss rate.

[0007] mMTC services are designed to support a large number of devices over a long lifespan through energy-efficient communication channels, where data transmission between each device is sporadic and infrequent. For example, a single cell may need to support thousands of devices.

[0008] The present invention relates to various improvements to cellular wireless communication systems. Summary of the Invention

[0009] The present invention provides a simplified overview of some concepts, which will be further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0010] As defined by the claims, this invention provides a method for transmitting downlink control information in a cellular communication network using the OFDM transmission format, comprising: sending a DCI message containing at least one additional field from a base station to a UE operating in the network, wherein the message is dynamically allocated n times for application to a transport block to be transmitted by the UE.

[0011] The UE operating in the network responds to the DCI message by transmitting the n repetitions of the transport block.

[0012] The TDRA table included in the DCI message contains at least one additional field whose assignment is to be applied to the n repetitions of the transport block.

[0013] The at least one additional field includes a repeat indicator associated with at least one SLIV entry in the TDRA table.

[0014] The at least one additional field includes a repeat indicator associated with multiple SLIV entries in the TDRA table.

[0015] The at least one additional field includes a repeat indicator associated with multiple SLIV entries in the TDRA table. Multiple SLIV entries are assigned to a single repeat in the TB.

[0016] The at least one additional field includes a parameter in the DCI message that indicates the n repetitions to be applied to a transport block.

[0017] The parameter is the RRC parameter.

[0018] The parameter is an existing RRC parameter, extended to indicate the n repetitions.

[0019] Each repetition of the transport block includes a redundant version of the dynamically configured data sent by the UE to the base station.

[0020] The base station and / or the UE need to perform a listen-before-transmit check.

[0021] The UE preempts transmission by utilizing the additional repetition of higher-priority transmission blocks in the time slots allocated to lower-priority transmission blocks.

[0022] The cellular communication network operates in both licensed and unlicensed spectrum.

[0023] The n repetitions are scheduled as n repetitions of a transport block with n PUSCH repetitions.

[0024] The present invention may also include a base station configured to operate the method.

[0025] The present invention may also include a UE configured to decode a DCI message transmitted according to the method described herein and to transmit the n repetitions of the transport block in response to the DCI message.

[0026] The present invention can further provide a method for transmitting downlink control information in a cellular communication network using the OFDM transmission format, the method comprising: sending a TDRA table contained in a DCI message from a base station to a UE operating in the network, the DCI message containing at least one additional field dynamically allocated n times for application to a transport block to be transmitted by the UE.

[0027] The present invention can further provide a method for transmitting downlink control information in a cellular communication network using the OFDM transmission format, the method comprising: sending parameters in a DCI message from a base station to a UE operating in the network, the parameters dynamically indicating n repetitions to be applied to a transport block to be transmitted by the UE.

[0028] Non-transitory computer-readable media may include at least one of the following groups: hard disk, CD-ROM, optical storage device, magnetic storage device, read-only memory, programmable read-only memory, erasable programmable read-only memory, EPROM, electrically erasable programmable read-only memory, and flash memory. Attached Figure Description

[0029] Further details, aspects, and embodiments of the invention will be described by way of example only with reference to the accompanying drawings. The components in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. Similar reference numerals have been included in the corresponding drawings for ease of understanding.

[0030] Figure 1 Selected components of a cellular communication network are shown.

[0031] Figures 2 to 7 The scheduling of transport blocks in a time slot is shown. Detailed Implementation

[0032] Those skilled in the art will recognize and understand that the details of the described examples are merely illustrative of some embodiments and that the teachings set forth herein are applicable to various alternative settings.

[0033] Figure 1 This diagram illustrates a cellular network formed by three base stations (e.g., eNB or gNB depending on the specific cellular standard and terminology). Typically, each base station will be deployed by a cellular network operator to provide geographic coverage for UEs in that area. The base stations form a Radio Area Network (RAN). Each base station provides radio coverage for UEs in its area or cell. The base stations interconnect via an X2 interface and connect to the core network via an S1 interface. It should be understood that only basic details are shown for the purpose of illustrating key characteristics of a cellular network. A PC5 interface is provided between UEs for sidelink (SL) communication. Figure 1 The related interface and component names are for illustrative purposes only. Different systems may use different naming conventions as they operate on the same principles.

[0034] Each base station contains the hardware and software for implementing RAN functions, including communication with the core network and other base stations, control and data signaling between the core network and UEs, and maintaining wireless communication with the UEs associated with each base station. The core network includes the hardware and software for implementing network functions, such as overall network management and control, and call and data routing.

[0035] In unlicensed spectrum, UEs may have to transmit TBs with different priorities and requirements. To ensure that the UL transmission of each TB meets the specified requirements, the gNB schedules each TB with a specific number of repetitions.

[0036] In uplink transmissions, a single Physical Uplink Shared Channel (PUSCH) transmission instance is not allowed to cross the slot boundaries of both Dynamic Grant (DG) and Configured Grant (CG) PUSCHs. Therefore, to avoid transmitting long PUSCHs across slot boundaries, the UE can transmit small PUSCHs in several repetitions scheduled by UL grant or radio resource control (RRC) within consecutive available transport sub-slots / slots. Using PUSCH repetition for a transport block (TB) also reduces latency and increases the reliability of PUSCH transmission, where the UE can be configured to transmit multiple TB repetitions across consecutive transmission times without feedback. In PUSCH repetition type A, each slot contains only one repetition, and the time domain of the TB repetitions is the same across these slots. In PUSCH repetition type B, repetitions are performed in consecutive micro-slots, so a slot may contain multiple repetitions of a TB.

[0037] In unlicensed spectrum, the transmitter needs to listen-before-talk (LBT) to check channel availability before transmission. In UL DG transmissions, the UE can access the channel according to the Type 1 or Type 2 UL channel access procedure indicated by the UL grant DCI. When the UE has a TB to transmit, it sends a scheduling request to the gNB. The gNB responds with a DCI as a UL grant to schedule the UL transmission. This DCI provides information about the UL transmission, such as time and frequency resources, repetition count, transmission power, modulation and coding scheme, and channel access type in the unlicensed spectrum. TBs are transmitted on allocated PUSCHs, with each repetition corresponding to one PUSCH. One DCI as a UL grant can schedule multiple TBs across multiple PUSCHs.

[0038] Standards (e.g., 3GPP Technical Standard 38.913) require UL transmissions in the TB to support multiple repetitions to meet stringent URLLC requirements. The Time Domain Resource Assignment (TDRA) field in the DCI indicates the resources for the first “nominal” repetition. The time domain resources for the remaining repetitions are derived from the information provided for the UL / DL direction of the first repetition and symbol. The repetition count represents the “nominal” repetition count. In the TDRA tables using DCI formats 0_1 and 0_2, the dynamic indication of the dynamically authorized repetition count is jointly encoded with the start and length indicator value (SLIV), indicating the start symbol and length of the scheduling resources used for PUSCH, by adding an additional column for the repetition count in the TDRA table. The maximum size of the TDRA table is 64. For CG PUSCH transmissions, if the repetition count is not included in the TDRA table, it is provided by the RRC parameter repK.

[0039] In unlicensed spectrum, transmission of multiple PUSCHs of different TBs is supported via a single DCI format 0_1. A single DCI format 0_1 ​​can schedule one or more PUSCHs. The maximum number of PUSCHs that can be scheduled in a single DCI is 8. An extended TDRA table is used, with each row representing multiple PUSCHs. Each PUSCH has a separate SLIV. The number of scheduled PUSCHs is indicated by the number of valid SLIVs in the rows of the TDRA table.

[0040] However, the transmission of multiple PUSCHs scheduled by a single DCI in unlicensed spectrum does not support the retransmission of PUSCHs in URLLC-licensed spectrum. Incompatibility between two transmission schemes with two different TDR table types causes problems when supporting URLLC operation in unlicensed spectrum. Without repeated PUSCH transmissions for each PUSCH, reliability is reduced and transmission latency is increased. Long PUSCH transmissions cannot cross slot boundaries or be transmitted in resources segmented by DL symbols in a TDD configuration. In those cases, short PUSCH repetition is required to transmit the TB, where repetition can be segmented by slot boundaries or DL ​​symbols. On the other hand, using a DCI to schedule each PUSCH increases DCI overhead and LBT latency.

[0041] Figure 2 Scenario 1 shows that the gNB issues a DCI to continuously schedule 8 PUSCHs for 8 TBs. Figure 2Scenario 2 shows that the gNB issues a PUSCH for a TB, repeats it 4 times, and then issues 3 more PUSCHs for 3 TBs. The repetition of TB1 is treated as a PUSCH for a different TB, and therefore indicated by different SLIVs in the TDRA table, leading to increased DCI overhead and latency due to LBT at the gNB. The current TDRA table for multiple TB scheduling is shown below:

[0042]

[0043] Table 1

[0044] Multiple TBs that repeat within each TB are scheduled by a single DCI to reduce control overhead and LBT latency. The number of repetitions of each TB in a scheduled TB group may vary depending on the priority, reliability, and latency requirements of each TB. Figure 2 The four repetitions of TB1 in Scenario 2 correspond to SLIV1, SLIV2, SLIV3, and SLIV4 in TDRA index 3 of Table 1. TB1 uses four out of the eight SLIVs alone, so the other TBs are left with only four SLIVs. TB2-5 use SLIV5-8 respectively. Therefore, a single DCI schedules only five TBs instead of eight TBs.

[0045] The repetition count is dynamically indicated to the UE by expanding the standard TDRA table with columns to indicate the repetition count of each entry in the SLIV of the TB, as shown in Table 2 below. The TDRA field in the UL Authorization DCI indicates the value of the TDRA index, so the UE knows the entries used in the table. For example, if the UL Authorization indicates TDRA index 1, then 2 TBs are scheduled. The first TB corresponds to SLIV1 and Rep1. The second TB corresponds to SLIV2 and Rep2.

[0046]

[0047] Table 2

[0048] The number of entries in the new TDRA table increases to indicate SLIVs and repetition counts. If the current TDRA table has 2 entries... a Where 'a' is the number of bits in the TDRA field of the DCI, the number of entries in the new TDRA table is 2. a+N*b , where N is the number of TBs scheduled, and b is the number of bits indicating the number of repetitions for each TB. Depending on the maximum allowed number of repetitions, b may be 2 bits or 3 bits.

[0049] This table does not need to carry all possibilities regarding the number of TBs and the number of repetitions. One approach is to give a total number of bits for the TDRA table, say n, then the TDRA table can have 2^n bits. nEach entry. The base station can configure the TDRA table using the appropriate entries it intends to use. This can be used to design the TDRA table for the desired number of bits, and then the base station only configures entries that may have that number of bits.

[0050] A TB is represented by a SLIV and a repetition count. That is, one SLIV corresponds to only one TB, not a PUSCH repetition of a TB. For example, in Table 2, TB1 is represented by SLIV1 and Rep1. SLIV1 represents the starting symbol and length of the first repetition of TB1. Resources for repetitions after the first repetition are derived based on the repetition count Rep1, the length of a repetition, the slot boundaries, and the UL / DL symbol configuration.

[0051] Alternatively, a slightly modified version of the TDRA table in Table 2 can be used with the new field indicating the number of repetitions for each SLIV, as shown in Table 3 below.

[0052]

[0053] Table 3

[0054] The indicated repetition count is the nominal repetition count per TB. If the nominal repetition encounters a slot boundary or DL ​​symbol in the TDD configuration and this repetition is split into multiple repetitions, the actual repetition count per TB may be larger. With these extended TDRA tables, even if there are multiple repetitions per TB, a row in the TDRA table still has a maximum of 8 TBs corresponding to 8 SLIVs that can be scheduled by a single DCI.

[0055] These extended tables can also be used to arrange repeating TBs in the URLLC-licensed spectrum. This avoids using two different TDRA tables for different scenarios: one table for multiple TBs in the unlicensed spectrum and another table for multiple repetitions of a TB in the URLLC-licensed spectrum.

[0056] Alternatively, the TDRA table shown in Table 1 is used to schedule multiple TBs in unlicensed spectrum, and the number of repetitions is indicated by a separate field in the DCI, such as... Figure 3 As shown.

[0057] In the TDRA table, an SLIV corresponds to a TB, representing the first repetition of that TB. Subsequent repetitions are derived from the number of repetitions indicated in a new field added to the UL-authorized DCI, along with information about the length of a repetition, slot boundaries, and UL / DL symbol configuration. The length of the repetition indication field depends on the number of scheduled TBs and the number of repetitions per TB. If there are no repetitions in the scheduled TBs (each TB is transmitted only once on a PUSCH), the repetition indication field can be removed. This provides flexibility in the DCI length, which helps reduce the DCI bit count and increase DCI reliability.

[0058] Alternatively, the number of repetitions of each TB in multiple TB transmissions of 'a' can be indicated by the RRC parameter. The RRC parameter pusch-AggregationFactor can be extended to indicate the number of repetitions of multiple scheduled TBs. The TDRA table for multiple PUSCH transmissions on unlicensed spectrum is the same as Table 1. When configuring the pusch-AggregationFactor, the UE obtains the number of TB repetitions from the pusch-AggregationFactor, uses SLIV as the indicator of the first repetition of the TB, and derives the resources for the remaining repetitions.

[0059] When a TB is transmitted multiple times, a redundancy version (RV) sequence must be indicated to determine the RV for each repetition. However, in the current standard, if a single DCI schedules multiple PUSCHs, where each PUSCH corresponds to one SLIV, then each PUSCH has only 1 RV bit. Therefore, in multiple repeated TB transmissions, each TB has only 1 RV bit because one TB corresponds to one SLIV. One RV bit is insufficient to indicate the RV sequence for multiple repetitions of a TB. For example, a TB with 4 repetitions requires 2 bits to indicate the RV sequence: {0,0,0,0}, {0,3,0,3}, or {0,2,3,1}.

[0060] To address this issue, the number of RV bits for each TB can be flexibly configured. The number of RV bits for a TB corresponds to the number of repetitions of the TB, as shown in Table 4. If the number of repetitions of a TB is 1 or 2, then the number of RV bits for that TB is 1. If the number of repetitions is 1, the RV field indicates {0,2}. If the number of repetitions is 2, then the RV field indicates {(0,2),(0,3)}. This means that the two PUSCH repetitions of a TB may have RVs of 0 and 2 or 0 and 3. On the other hand, if the number of repetitions of a TB is greater than 2, then the number of RV bits for that TB is 2. For example, for 4 repetitions, 2 bits are needed to indicate the RV sequence. The UE decodes the number of repetitions of the TB in the TDRA table, the repetition indication field, or the RRC parameter to determine the number of RV bits in the RV field of the corresponding TB.

[0061] NoRep1: 1 repetition NoRep2: 1 repetition NoRep3: 4 repetitions NoRep4: 8 repetitions RV1: 1 bit RV2: 1 bit RV3: 2 bits RV4: 2 bits

[0062] Table 4

[0063] When a gNB schedules multiple repeating Transport Blocks (TBs) in unlicensed spectrum via a single DCI, if there are URLLC TBs in the group, the delay budget for the URLLC TBs must be guaranteed to be 1 ms. However, different channel access priorities result in different channel access delays. This can cause URLLC transmissions to fail to meet the specified delay requirements. Therefore, a 2-bit field is added to the scheduling DCI to indicate the channel access priority of multiple TB transmissions (2 bits correspond to 4 channel access priorities). The channel access priority category is selected and indicated to the UE to ensure that the URLLC TB and its repeats are transmitted within the delay budget. The selected channel access priority depends on the channel conditions, the location of the URLLC resource, and the number of repetitions of each URLLC TB.

[0064] Alternatively, TBs with the same Quality of Service (QoS) are typically scheduled together by a single DCI, and all TBs are repeated the same number of times. In other words, a single DCI schedules multiple TBs with the same number of repetitions.

[0065] In UL scheduling, when a single DCI schedules multiple TBs, the reliability of multiple TB transmissions is also related to the scheduling of the DCI. When the gNB allocates resources to multiple TBs, the exact order of the TBs depends on the arrival of the data packets and the MAC layer procedures / implementation. If the PUSCH is reused for all TBs in a group, the gNB can schedule the same number of repetitions for all TBs in that group, thus reducing DCI overhead and improving DCI reliability because fewer bits are needed to indicate the number of repetitions.

[0066] To enable a single DCI to schedule multiple TBs, each with the same number of repetitions, the TDRA table in Table 5 can be used.

[0067]

[0068] Table 5

[0069] This can be used for scheduling multiple TBs in unlicensed spectrum and repeating TBs in URLLC licensed spectrum.

[0070] Each TB corresponds to a SLIV, indicating the resource for the first repetition. The UE then derives the further resources (if any) for subsequent repetitions based on the nominal repetition count indicated in the repetition count column of Table 5 of TDRA. This applies to all TBs scheduled by a single DCI. If the nominal repetition encounters a slot boundary or DL ​​symbol in the TDD configuration, and this repetition is split into multiple repetitions, the actual repetition count may be larger.

[0071] Alternatively, while using the TDRA as described in Table 1 above, the number of repetitions of TBs in a group is defined using a new field in the DCI. This field contains either 2 bits or 3 bits, depending on the set of allowed repetitions for the TB. The repetition count indicated in this new field of the scheduling DCI applies to all TBs in the group.

[0072] As mentioned above, the repetition of multiple TBs scheduled by a single DCI can be indicated by the RRC parameter. The RRC parameter `pusch-AggregationFactor` represents the number of repetitions of a TB, and the value in `pusch-AggregationFactor` applies to all TBs in a group scheduled by a single DCI. The TDRA in Table 1 can be used for multiple PUSCH transmissions in unlicensed spectrum. When `pusch-AggregationFactor` is configured and the UE obtains the number of TB repetitions from `pusch-AggregationFactor`, the UE uses SLIV as an indication of the first repetition and derives resources for the remaining repetitions.

[0073] As mentioned above, if the repetition count is greater than 2, two RV bits can be used to indicate the repeating RV sequence for each TB. Otherwise, one RV bit is used. The UE finds the repetition count by decoding the DCI or RRC, and then can determine the corresponding number of RV bits to extract the RV information.

[0074] In unlicensed spectrum, the UE must perform a Level Bypass (LBT) before uplink data transmission, so the LBT result is indeterminate. If the LBT succeeds before the start symbol of the scheduled resource, the UE can transmit a Transport on the UL resource. Conversely, if the LBT initially fails and then succeeds only after the start symbol of the scheduled resource, the scheduled transmission is not initiated and the PUSCH is discarded. The gNB will then have to reschedule the resource for this PUSCH, which in turn increases latency and is detrimental to the QoS of URLLC.

[0075] When a UE cannot initiate transmission at the predetermined location due to channel access uncertainty, it should transmit on the predetermined resources after obtaining channel access. When the UE accesses the channel later, this may result in insufficient repetitions for the initial TB, as it leaves fewer repetitions than scheduled for a given TB. This can negatively impact the performance of URLLCs with high reliability requirements.

[0076] like Figure 4As shown in Scenario 1, a single DCI schedules 2 TBs, each TB repeated 4 times. LBT succeeds before S1, so the UE can send TB1 from S1 to S4, repeated 4 times, and from S5 to S8, send TB2, repeated 4 times (S1, ..., S8 are sub-slots or slots, depending on the mapping and repetition type). However, in Figure 4 In scenario 2, LBT fails before S1 and succeeds only before S2. Therefore, the UE can only send TB 1 three times from S2 to S4, instead of the planned four times. This could be harmful if TB1 has high reliability requirements.

[0077] To address this issue, the UE may override base station (gNB) scheduling to use additional resources to repeat the transmission block, when some of its repeating resources are lost due to acquisition delays and at the nominal start time when acquiring the channel later.

[0078] High-priority TBs can use the resources of low-priority TBs, thus ensuring the reliability of high-priority TBs in the event of LBT failure. Multiple SLIVs from the proposed TDRA table can be used to schedule PUSCH transports from multiple origins. Multiple SLIVs are associated with a single PUSCH, and each SLIV indicates a potential origin.

[0079] like Figure 5 As shown, four TB1 repetitions are scheduled from S1 to S4, and four TB2 repetitions are scheduled from S5 to S8. However, in scenario 2, the LBT fails before S1 and the UE cannot start transmission. The UE can only start transmission in S2 after transmission has occurred. TB1 has a higher priority than TB2, so the UE preempts S5 from TB2 and allocates it to TB1 to transmit the fourth repetition, thus transmitting all four configured repetitions to achieve high-priority transmission reliability. Although TB2 has a lower priority, the transmission of TB2 is offset from S5 to S6. Only three TB2 repetitions are performed from S6 to S8. On the other hand, in scenario 3, TB2 has a higher priority than TB1, so the transmission of TB2 still starts at S5 as scheduled in the SLIV, thus ensuring four repetitions of TB2 and only transmitting three repetitions of TB1.

[0080] If the LBT succeeds only at the start of the second scheduled TB and the first scheduled TB has a higher priority than the second TB, the UE can send the first TB and discard the second TB. For example, in Figure 5 In scenario 4, if LBT succeeds in S5 and TB1 has a higher priority than TB2, then the UE will transfer TB1 instead of TB2 from S5 to S8.

[0081] The gNB can determine the LBT result and the UE offset low-priority TB start symbol determination by decoding the UCI multiplexed with the PUSCH. The UCI contains one bit to indicate the expected sub-slot / slot offset. Alternatively, the UCI can contain the HARQ ID corresponding to the TB being transmitted so that the gNB can determine the offset. For example, in Figure 5 In scenario 2, the four repetitions of TB1 have HARQ ID 1, and the four repetitions of TB2 have HARQ ID 2. In the case of scenario 2 coverage, S5 contains the repetitions of TB1, not the initially configured TB2. Therefore, the UCI at S5 contains the HARQ ID of TB1, not the HARQ ID of TB2 as expected by the scheduling. The gNB recognizes this HARQ ID and can determine that S5 contains the repetitions of TB1, not the repetitions of TB2. Therefore, the gNB can perform soft combination among the repetitions of TB1. The gNB can also determine that the UE has offset the transmission of TB2 to the next transmission timing S6, so it will start decoding the first repetition of TB2 from S6.

[0082] If a scheduled PUSCH cannot be transmitted on the first scheduled symbol due to LBT failure, the UE can transmit the PUSCH on any subsequent symbol of the scheduled resource after LBT success, instead of discarding the entire PUSCH. The gNB detects the start of transmission by blindly decoding the DMRS at each symbol in the scheduled resource. This scheme guarantees PUSCH transmission as long as LBT succeeds before the last symbol of the scheduled resource. However, this has two drawbacks. First, the gNB must blindly detect the DMRS in each scheduled symbol to find the start of transmission. Second, the length of the PUSCH resource indicated by SLIV is fixed, regardless of whether LBT succeeds at the first symbol of that resource. If the UE transmits the PUSCH after the first symbol of the scheduled resource, it must transmit a shorter PUSCH than configured, which reduces the reliability of PUSCH transmission.

[0083] To handle the uncertainty of LBT results, the DCI uses a TDRA table with multiple SLIVs to schedule only one PUSCH instead of multiple PUSCHes. When the gNB schedules a high-priority UL TB (e.g., a URLLC TB), it uses one row from the TDRA table and multiple SLIVs to schedule the TB. Each SLIV corresponds to a potential start point and length of the transmission. The UE selects to follow a SLIV based on the LBT result. To meet URLLC latency requirements, the UE selects the nearest start point after a successful LBT. The transmission length indicated in each SLIV also guarantees the required reliability of the transmission.

[0084] This reduces the number of symbols the gNB must search the DMRS to determine the start of a transmission. This number is equal to the number of SLIVs used by the gNB. Furthermore, the TDRA in Tables 1, 2, 3, or 5 of the unlicensed spectrum can be used to schedule transmissions with multiple origins, instead of using new fields in the DCI or the new RRC to indicate flexible origins. SLIVs in the TDRA table are used to indicate multiple origins within a single TB.

[0085] like Figure 6 As shown, the gNB schedules a PUSCH transmission with three SLIVs: SLIV1 has a start symbol S1 and a length L, SLIV2 has a start symbol S3 and a length L, and SLIV3 has a start symbol S5 and a length L. If the LBT succeeds before S1, the UE uses SLIV1 to transmit the PUSCH. If the LBT succeeds between S1 and S3, the UE uses SLIV2 to transmit the PUSCH. If the LBT succeeds between S3 and S5, the UE uses SLIV3 to transmit the PUSCH. The three SLIVs all indicate a length of L, ensuring the reliability of the PUSCH transmission, although this transmission type requires more resources.

[0086] The UE sends a scheduling request to the gNB to request resources for a single PUSCH TB transmission. If the UE receives a DCI UL grant indicating multiple SLIVs, it can determine that these SLIVs are for a single PUSCH TB with multiple origins, rather than multiple PUSCH TB transmissions. The UE will only use one of these SLIVs to transmit the PUSCH TB based on the LBT result.

[0087] Therefore, resources can be sacrificed in exchange for the latency and reliability of high-priority transmissions in URLLC.

[0088] When a UE has multiple TBs to transmit, the gNB can repeatedly schedule multiple TB transmissions for each TB using a single DCI. The gNB indicates the number of SLIVs and the number of repetitions for each TB based on demand. Furthermore, the gNB may need to account for LBT uncertainties in any scheduling scheme for time-sensitive TBs. This results in increased DCI load for repeatedly scheduling multiple TBs because the TDRA table has more entries and requires more RV bits. This impacts the performance of DCI transmissions, and channel uncertainties may still limit the performance of such multiple TB repetition schemes.

[0089] A common resource allocation scheme for multiple uplink transmissions allows the gNB to schedule multiple resources for the UE via an optimized single UL-granted DCI. The UE can then use these resources to transmit multiple repetitions of multiple transport blocks. Therefore, this scheme significantly simplifies signaling overhead and addresses channel uncertainties that cause delayed initiation of bulk uplink transmissions. Each resource transmitted by the UE includes necessary information such as a hybrid automatic repeat request (HARQ) identity (ID), redundancy version (RV), and new data indicator (NDI) to allow for proper decoding and buffer management for soft-merging by the gNB.

[0090] To reduce the scheduling burden on the gNB and the DCI load in repeated multiple TB transmissions, and to address channel uncertainties more flexibly, a general resource allocation scheme for uplink transmissions can be used. Upon receiving a scheduling request and / or buffer status report from the UE, the gNB can determine the UE's traffic requirements, and based on available resources and traffic conditions from other devices, the gNB's scheduler can accommodate a given number of TBs with a given number of repetitions. The gNB indicates resources to the UE without explicitly specifying the number of TBs or the number of repetitions for each TB. Therefore, the UL-authorized DCI will indicate general resources to the UE. Upon receiving this resource allocation for uplink transmission, the UE will begin transmitting its TBs, repeating them appropriately in these resources to meet the TB requirements. If the UE has multiple TBs with different requirements in its buffer, it sends an SR to the gNB to request resources to transmit these TBs. To reduce DCI and LBT latency, the gNB uses a single DCI to schedule multiple TBs.

[0091] The gNB can use a variety of different signaling options to indicate multiple resources allocated to a UE. If the gNB has the same time-frequency resource available in multiple time slots, and it allocates this resource to a single UE, the gNB uses a TDRA table with only one SLIV per row to schedule a single TB. The SLIV indicates the start symbol and the length of the U resource in the time slot that the UE can use to transmit the TB. A new RRC parameter, PUSCH-resourceRepetition, can be configured to indicate the number of time slots allocated.

[0092] like Figure 7 As shown, the gNB indicates the UL resources in Slot 1 via SLIVs with S=1 and L=6. It configures PUSCH-resourceRepetition to 2, so resources in slot 1 are repeated in slot 2 in the same time domain.

[0093] The UE can use the resources indicated by SLI and PUSCH-resourceRepetition to transmit TBs in the buffer. The UE determines the transmission order of TBs and the number of repetitions for each TB to meet the TB requirements. The UE also selects the RV sequence for TB repetition.

[0094] UCI can be multiplexed in a PUSCH containing the HARQ ID and RV. By decoding the UCI, the gNB obtains information about the corresponding PUSCH and can determine the first repetition of the TB when it receives a new HARQ ID and a repeated RV, so that the gNB can perform soft combination.

[0095] If the gNB encounters a decoding error and must arrange a retransmission, to further reduce latency, the UCI carries an indication to inform the UE whether the retransmission is the last one in the TB. If the gNB uses the HARQ ID to determine the new transmission and there is a gap between the two resources, such as... Figure 7 As shown, the gNB must wait from the middle of time slot 1 to the beginning of time slot 2 to determine if it received the last repetition of the TB in time slot 1 before rescheduling the TB if necessary. If the last repetition of the TB is in time slot 1, the gNB can quickly reschedule the TB in the event of a decoding error.

[0096] In alternative signaling schemes for allocating multiple resources, when the gNB does not have the same time-frequency resources in multiple time slots, it can indicate different resources in different time slots to the UE. Multiple resources can be indicated to the UE through a TDRA table with multiple SLIV values, where each TB may have one repeating value, or through a table with multiple SLIV values, where each SLIV has one repeating value. The UE will select the number of TBs and the number of repeats for each TB. The HARQ ID, RV, Last Repeat Indicator, and New Data Indicator (NDI) are multiplexed with the PUSCH on each individual resource transmitted by the UE as part of the UCI. This ensures that the gNB does not confuse the content transmitted by the UE.

[0097] When the gNB schedules a single TB (Resource Terminate) for UL (Ultra-Legion) transmission, it can use the SLIV (Single Resource Terminate) to indicate the start symbol and resource length of that TB. When the UE sends an SR (Request Request) to the gNB to request resources for a TB, the gNB sends a UL Authorization DCI (Distribution Code Instruction) to allocate resources for the UE to transmit that TB. The DCI does not specify the number of repetitions for the TB, but the UE will determine it based on the TB's length, resources, and QoS. The SLIV used in the DCI indicates the start symbol and resource length of the TB. The RV (Repetition Resource Term) for each repetition is also determined by the UE and communicated to the gNB via the UCI (Usage Code Instruction) multiplexed with the PUSCH. The gNB can also use a new RRC parameter, PUSCH-resourceRepetition, to indicate the repetition of resources in consecutive time slots.

[0098] Although not shown in detail, any device or apparatus forming part of the network may include at least a processor, memory, and a communication interface, wherein the processor, memory, and communication interface are configured to perform any aspect of the invention. Further options and choices are described below.

[0099] The signal processing functions of embodiments of the present invention can be implemented using computing systems or architectures known to those skilled in the art, particularly gNBs and UEs. Computing systems, such as desktops, laptops or notebooks, handheld computing devices (PDAs, mobile phones, PDAs, etc.), mainframes, servers, clients, or any other type of dedicated or general-purpose computing device, may be ideal or suitable for a given application or environment. The computing system may include one or more processors, which can be implemented using general-purpose or dedicated processing engines such as microprocessors, microcontrollers, or other control modules.

[0100] A computing system may also include main memory, such as random access memory (RAM) or other dynamic memory, for storing information and instructions to be executed by the processor. Such main memory can also be used to store temporary variables or other intermediate information during the execution of instructions to be executed by the processor. A computing system may also include read-only memory (ROM) or other static storage devices for storing static information and instructions for the processor.

[0101] The computing system may also include an information storage system, which may include, for example, media drives and removable storage interfaces. Media drives may include drives or other mechanisms that support fixed or removable storage media, such as hard disk drives, floppy disk drives, magnetic tape drives, optical disc drives, optical disc (CD) or digital video drive (DVD) (RTM) read or write drives (R or RW), or other removable or fixed media drives. Storage media may include, for example, hard disks, floppy disks, magnetic tapes, optical discs, CDs or DVDs, or other fixed or removable media read and written by media drives. Storage media may include computer-readable storage media in which specific computer software or data is stored.

[0102] In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components may include, for example, removable storage units and interfaces, such as program boxes and box interfaces, removable memory (e.g., flash memory or other removable memory modules) and memory slots, as well as other removable storage units and interfaces that allow software and data to be transferred from the removable storage units to the computing system.

[0103] The computing system may also include a communication interface. Such a communication interface can be used to allow software and data to be transferred between the computing system and external devices. Examples of communication interfaces may include modems, network interfaces (such as Ethernet or other NIC cards), communication ports (such as Universal Serial Bus (USB) ports), PCMCIA slots and cards, etc. Software and data transmitted via the communication interface are in the form of signals, which may be electronic, electromagnetic, optical, or other signals that can be received by the communication interface medium.

[0104] In this document, the terms "computer program product," "computer-readable medium," etc., are generally used to refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor constituting a computer system to cause the processor to perform specified operations. Such instructions, typically referred to as "computer program code" (which may be grouped as computer programs or other groups), when executed, enable the computing system to perform the functions of embodiments of the present invention. Note that code may directly cause the processor to perform specified operations, be compiled to perform such operations, and / or be combined with other software, hardware, and / or firmware components (e.g., libraries for performing standard functions) to perform such operations.

[0105] Non-transitory computer-readable media may include at least one from the group consisting of: hard disks, CD-ROMs, optical storage devices, magnetic storage devices, read-only memory, programmable read-only memory, erasable memory, EPROM, electrically erasable programmable read-only memory, and flash memory. In embodiments using software-implemented components, the software may be stored in a computer-readable medium and loaded into a computing system using, for example, a removable storage drive. When executed by a processor in a computer system, a control module (in this example, software instructions or executable computer program code) causes the processor to perform the functions of the invention as described herein.

[0106] Furthermore, the inventive concept can be applied to any circuit used to perform signal processing functions within a network element. It is further envisioned that, for example, semiconductor manufacturers can incorporate the concepts of this invention into the design of standalone devices, such as microcontrollers for digital signal processors (DSPs), or application-specific integrated circuits (ASICs), and / or any other subsystem components.

[0107] It should be understood that, for clarity, the above description has referred to embodiments of the invention with reference to a single processing logic. However, the inventive concept can also be implemented by multiple different functional units and processors to provide signal processing functions. Therefore, references to specific functional units are to be regarded only as references to suitable means for providing said functions, and not as indications of strict logical or physical structure or organization.

[0108] The aspects of this invention can be implemented in any suitable form, including hardware, software, firmware, or any combination thereof. The invention can optionally be implemented, at least in part, as computer software running on one or more data processors and / or digital signal processors or configurable modular components such as FPGA devices.

[0109] Therefore, the components and elements of embodiments of the present invention can be implemented physically, functionally, and logically in any suitable manner. In fact, functionality can be implemented in a single unit, in multiple units, or as part of other functional units. Although the invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific forms set forth herein. Rather, the scope of the invention is limited only by the appended claims. Furthermore, although features may appear to be described in conjunction with specific embodiments, those skilled in the art will recognize that various features of the described embodiments can be combined according to the invention. In the claims, the term "comprising" does not exclude the presence of other components or steps.

[0110] Furthermore, although listed separately, multiple means, elements, or method steps can be implemented by, for example, a single unit or processor. Additionally, while individual features may be included in different claims, these can be advantageously combined, and inclusion in different claims does not imply that the combination of features is infeasible and / or unadvantageous. Moreover, including a feature in one class of claims does not imply a limitation on that class, but rather indicates that the feature is equally applicable to other claim classes, as the case may be.

[0111] Furthermore, the order of features in the claims does not imply any particular order in which these features must be performed; in particular, the order of the steps in a method claim does not imply that these steps must be performed in this order. Rather, these steps can be performed in any suitable order. Moreover, singular references do not exclude plural forms. Therefore, references to “a,” “an,” “first,” “second,” etc., do not exclude plural forms.

[0112] Although the invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific forms set forth herein. Rather, the scope of the invention is limited only by the appended claims. Furthermore, although features may appear to be described in conjunction with specific embodiments, those skilled in the art will recognize that various features of the described embodiments can be combined according to the invention. In the claims, the terms "comprising" or "including" do not exclude the presence of other components.

Claims

1. A method of transmitting downlink control information in a cellular communications network using an OFDM transmission format, characterised by, comprising: transmitting, from a base station to a UE operating in a network, a DCI message containing at least one additional field dynamically allocating n repetitions to be applied to a transport block to be transmitted by the UE, a TDRA table in the DCI message containing at least one additional field, the at least one additional field comprising a repetition indicator associated with a plurality of SLIV entries in the TDRA table, the plurality of SLIV entries being allocated to a single repetition of a TB.

2. The method of claim 1, wherein, transmitting, by the UE operating in the network, the n repetitions of the transport block in response to the DCI message.

3. The method of claim 1, wherein, the at least one additional field allocating the n repetitions to be applied to the transport block.

4. The method of claim 1, wherein, the at least one additional field comprising a parameter in the DCI message, the parameter indicating the n repetitions to be applied to one transport block.

5. The method of claim 4, wherein, the parameter being an RRC parameter.

6. The method of claim 5, wherein, the parameter being an existing RRC parameter extended to indicate the n repetitions.

7. The method of claim 2, wherein, each repetition of the transport block comprising a dynamically configured redundancy version transmitted by the UE to the base station.

8. The method of claim 2, wherein, the base station and / or the UE requiring a listen-before-transmit check.

9. The method of claim 8, wherein, the UE pre-empting a transmission with an extra repetition of a higher priority transport block in a slot allocated to a lower priority transport block.

10. The method of claim 1, wherein, the cellular communication network operating in licensed and unlicensed spectrum.

11. The method of claim 1, wherein, the n repetitions being scheduled as n PUSCH repetitions of one transport block.

12. A base station, characterized by comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform the method of any of claims 1 to 11.

13. A UE, comprising: comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver; wherein the processor is configured to perform the method of any of claims 1 to 11, the processor decoding the DCI message, wherein the UE transmits the n repetitions of the transport block in response to the DCI message.

Images