User equipment and base station that execute transmission / reception processing

Abstract

SOLUTION: In a communication system, user equipment (UE) is configured to: receive a single uplink grant for a plurality of PUSCH transmissions; determine time-domain resources based on the received uplink grant; determine the number of symbols to be used for each of at least one front-loaded DMRS of the plurality of PUSCH transmissions based on a received index value; and, if at least two of the PUSCH transmissions have different lengths and if different numbers of symbols are permitted for each of the at least one front-loaded DMRS, transmit the same or a smaller number of PUSCH transmissions such that, for none of the included at least one front-loaded DMRS, a different determined number of symbols is used.EFFECT: The invention facilitates improving support for assignment of PUSCH transmissions with flexible timing and permitting an accurate channel estimation using DMRSs carried therein.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to signal transmission and reception in a communication system. In particular, the present disclosure relates to methods and apparatuses for such transmission and reception.

Background Art

[0002] The 3rd Generation Partnership Project (3GPP) is working on technical specifications for the next-generation cellular technology, also known as the 5th Generation (5G), which includes the "New Radio" (NR) radio access technology (RAT) operating in the frequency range up to 100 GHz.

[0003] NR is a successor to the technologies represented by Long Term Evolution (LTE) and LTE Advanced (LTE-A). NR is designed to facilitate providing a single technical framework that addresses a defined set of usage scenarios, requirements, and deployment scenarios, including, for example, enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine Type Communication (mMTC).

[0004] For example, the eMBB deployment scenario may include indoor hotspots, dense cities, rural areas, urban macro, and high speed. The URLLC deployment scenario may include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time vehicle control, and wide-area monitoring and control systems for smart grids. The mMTC deployment scenario may include scenarios with a large number of devices for non-time-critical data transmission, such as smart wearables and sensor networks.

[0005] eMBB and URLLC services are similar in that both require a very wide bandwidth, but differ in that URLLC services require ultra-low latency and very high reliability. In NR, the physical layer is based on time-frequency resources (such as OFDM (Orthogonal Frequency Division Multiplexing) in LTE) and supports multi-antenna operation.

[0006] For systems such as LTE and NR, further improvements and options can facilitate the efficient operation of the communication system, not only for specific devices related to the system.

Summary of the Invention

[0007] One non-limiting and exemplary embodiment facilitates improving the allocation of physical uplink shared channel (PUSCH) transmission by flexible timing and allowing accurate channel estimation using the demodulation reference signal (DMRS) carried therein.

[0008] In an embodiment, the technology disclosed herein features a user equipment (UE) including a receiver, a processor, and a transmitter. The receiver receives a single uplink grant for a plurality of PUSCH transmissions. The single uplink grant includes an antenna port field with an index value used for the plurality of PUSCH transmissions. The processor determines time domain resources based on the received uplink grant. The determined time domain resources define the number of PUSCH transmissions and the length of each PUSCH transmission.

[0009] The transmitter transmits a plurality of PUSCH transmissions using the determined time domain resources. Each PUSCH transmission includes at least one demodulation reference signal (DMRS) placed in front.

[0010] In particular, the processor determines the number of symbols to be used for each DMRS placed in front of at least one of the plurality of PUSCH transmissions based on the received index value, and when at least two of the plurality of PUSCH transmissions have different lengths and different numbers of symbols are allowed for each DMRS placed in front of at least one of them, the transmitter transmits the same number or fewer PUSCH transmissions so that the different determined numbers of symbols are not used for any of the at least one DMRS placed in front.

[0011] It should be noted that the overall or specific embodiments may be implemented as a system, method, integrated circuit, computer program, storage medium, or any selective combination thereof.

[0012] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. The benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and drawings, and not all of them need to be provided to obtain one or more of such benefits and / or advantages.

Brief Description of the Drawings

[0013] In the following, exemplary embodiments will be described in more detail with reference to the accompanying drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0014] As presented in the background section, 3GPP is working on the next release of the 5th generation cellular technology, simply called 5G, which includes the development of NR (New Radio) access technology operating in the frequency range up to 100 GHz. 3GPP needs to identify and develop the technical components required to successfully standardize the NR system to timely meet both the pressing market needs and the longer-term requirements. To achieve this, the evolution of the radio network architecture along with the radio interface is being considered in the research item “New Radio Access Technology” which is hereby incorporated by reference in its entirety. The results and agreements are collected in Technical Report TR 38.804 v14.0.0.

[0015] In particular, there is an agreement on the overall system architecture. NG-RAN (Next Generation - Radio Access Network) consists of gNBs that provide the termination to the UE of the NG - radio access user plane, SDAP / PDCP / RLC / MAC / PHY (Service Data Adaptation Protocol / Packet Data Convergence Protocol / Radio Link Control / Medium Access Control / Physical), and the control plane, RRC (Radio Resource Control) protocol. The NG-RAN architecture based on section 4 of TS 38.300 v15.0.0, which is incorporated herein by reference, is shown in Figure 1. The gNBs are interconnected with each other by the Xn interface. The gNBs are also connected to the NGC (Next Generation Core) by the NG (Next Generation) interface, more specifically, to the AMF (Access and Mobility Management Function) (e.g., a specific core entity that executes the AMF) by the NG-C interface, and to the UPF (User Plane Function) (e.g., a specific core entity that executes the UPF) by the NG-U interface.

[0016] For example, as reflected in "Study on new radio access technology: Radio access architecture and interfaces" of 3GPP TR 38.801 v14.0.0, various different deployment scenarios are being discussed to be supported. For example, a non-centralized deployment scenario (the centralized deployment in section 5.2 of TR 38.801 is shown in section 5.4 incorporated herein by reference) is presented there, and base stations supporting 5G NR can be deployed. Figure 2 shows an exemplary non-centralized deployment scenario, further showing an LTE eNB together with a user equipment (UE) connected to both a gNB and an LTE eNB, and is based on Figure 5.2-1 of TR 38.801. As described above, the new eNB for 5G NR may be exemplarily called a gNB.

[0017] Also, as described above, in 3GPP NR (3rd Generation Partnership Project New Radio), three use cases are being considered that are expected to support a wide range of services and applications by IMT-2020 (see Recommendation ITU-R M.2083: IMT Vision - "Framework and overall objectives of the future development of IMT for 2020 and beyond", September 2015). The phase 1 specifications for eMBB (enhanced Mobile-Broadband) were finalized by 3GPP in December 2017. In addition to further expanding eMBB support, current and future research will involve standardization for URLLC (Ultra-Reliable and Low-Latency Communications) and mMTC (massive Machine-Type Communications). Figure 3 (from Recommendation ITU-R M.2083) shows some specific examples of the expected use scenarios for IMT after 2020.

[0018] URLLC use cases have stringent requirements for capabilities such as throughput, latency, and availability, and have been envisioned as one of the enablers for future vertical applications such as wireless control of industrial manufacturing or manufacturing processes, remote surgery, distribution automation in smart grids, and transportation safety. In the current WID (Work Item Description) RP-172115, it has been agreed to support the ultra-reliability of URLLC by identifying technologies that meet the requirements set by TR 38.913. For NR URLLC in Release 15, the main requirements include a target user plane latency of 0.5 ms for UL (uplink) and 0.5 ms for DL (downlink). The general URLLC requirement for a single transmission of a packet is a BLER (Block Error Rate) of 1E-5 for a packet size of 32 bytes with a 1 ms user plane.

[0019] From the perspective of RAN1, reliability can be improved in a number of possible ways. The scope for improving reliability in Rel.15 is captured in RP-172817, which includes provisions such as a separate CQI table for URLLC, a more compact DCI format, and repetition of PDCCH. However, this scope may be extended to achieve ultra-reliability as NR becomes more stable and developed (see 3GPP TR 38.913 v15.0.0, “Study on Scenarios and Requirements for Next Generation Access Technologies”, which is hereby incorporated by reference for the main requirements of NR URLLC). Therefore, NR URLLC in Rel.15 should be able to transmit a 32-byte data packet within a 1 ms user plane latency with a success rate corresponding to a BLER of 1E-5. Specific use cases for NR URLLC in Rel.15 include extended reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications (see also ITU-R M.2083-0).

[0020] Also, the technical enhancements targeted by NR URLLC in Release 15 aim at improving latency and reliability. The technical enhancements for latency improvement include configurable numerology, non-slot-based scheduling by flexible mapping, grant-free (configured grant) uplink, slot-level repetition of data channels, and downlink preemption. Preemption means that a transmission for which resources have already been allocated is stopped and the resources already allocated are used for other transmissions that have been requested later but have lower latency / higher priority requirements. Therefore, a transmission that has already been permitted is preempted by later transmissions. Preemption is applicable independently of a specific service type. For example, a transmission for service type A (URLLC) can be preempted by a transmission for service type B (such as eMBB). The technical enhancements for reliability improvement include a dedicated CQI / MCS table for a target BLER of 1E-5 (for technical enhancements, refer to 3GPP TS 38.211 "NR, Physical channels and modulation", TS 38.212 "NR, Multiplexing and channel coding", TS 38.213 "NR, Physical layer procedures for control", and TS 38.214 "NR, Physical layer procedures for data", all of whose respective versions are V15.4.0 and are hereby incorporated by reference).

[0021] mMTC use cases are typically characterized by a very large number of connected devices that transmit data that is typically relatively insensitive to small amounts of latency. The devices are required to be low cost and have a very long battery life. From an NR perspective, using very narrow bandwidth portions is one possible solution for power savings from the UE perspective and enabling long battery life.

[0022] As described above, the range of reliability in NR is expected to be broader. One important requirement for all cases, especially for URLLC and mMTC, is high or ultra-reliability. Several mechanisms for improving reliability from a radio and network perspective can be considered. Generally, there are few important potential areas that can help improve reliability. Among these areas are compact control channel information, repetition of data / control channels, and diversity regarding the frequency domain, time domain, and / or spatial domain. These areas are generally applicable to reliability regardless of the specific communication scenario.

[0023] For NR URLLC Rel.16, additional use cases with more stringent requirements have been identified, including factory automation, transportation industry, and power distribution (see RP-181477 "New SID on Physical Layer Enhancements for NR URLLC", Huawei, HiSilicon, Nokia, Nokia Shanghai Bell, which is hereby incorporated by reference). The more stringent requirements include higher reliability (up to the 10^-6 level), higher availability, packet sizes up to 256 bytes, time synchronization on the order of several μs that can be a value of 1 or several μs depending on the frequency range, and short delays on the order of 0.5 to 1 ms, especially a target user plane delay of 0.5 ms, depending on the use case (see "Service requirements for next generation new services and markets" V16.4.0 and RP-181477, which are hereby incorporated by reference).

[0024] Furthermore, in NR-URLLC of Rel.16, several technical enhancements from the perspective of RAN1 have been identified. Among these, there are PDCCH (Physical Downlink Control Channel) enhancements related to compact DCI, PDCCH repetition, and increased PDCCH monitoring. In addition, UCI (Uplink Control Information) enhancements are related to enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback enhancements. Also, PUSCH enhancements related to mini-slot level hopping and retransmission / repetition enhancements have been identified. The term "mini-slot" refers to a TTI (Transmission Time Interval) that contains fewer symbols than a slot (a slot consisting of 14 symbols).

[0025] Generally, the TTI determines the timing granularity for scheduling allocations. One TTI is the time interval in which a given signal is mapped to the physical layer. Conventionally, the TTI length is variable from 14 symbols (slot-based scheduling) to 2 symbols (non-slot-based scheduling). Downlink and uplink transmissions are further specified to be organized into frames (with a duration of 10 ms) that are divided into slots, and the number of slots is defined by the numerology / subcarrier spacing, with the specified values ranging from 10 slots for a 15 kHz subcarrier spacing to 320 slots for a 240 kHz subcarrier spacing. The number of OFDM symbols per slot is 14 for a normal cyclic prefix and 12 for an extended cyclic prefix (see Sections 4.1 (Overall Frame Structure), 4.2 (Numerology), 4.3.1 (Frames and Subframes), and 4.3.2 (Slots) of 3GPP TS 38.211 v.15.4.0, which is incorporated herein by reference).

[0026] However, the allocation of time resources for transmission may also be non-slot-based. In particular, the TTI in non-slot-based allocation may correspond to a mini-slot rather than a slot. For example, one or more mini-slots may be allocated for the required transmission of data / control signaling. In non-slot-based allocation, the minimum length of the TTI may conventionally be in the range of 2 to 14 OFDM symbols.

[0027] PUSCH Repetition One area for potential enhancement is related to the mini-slot repetition of the PUSCH within a slot. In the following, a motivation is provided to support the repetition of the PUSCH within a slot that can enable potential enhancements to the repetition mechanism in order to further improve reliability and / or latency to meet the new requirements of NR URLLC. However, this motivation is not to be understood as imposing any constraints on the present disclosure.

[0028] To achieve the delay requirement for URLLC PUSCH transmission, if the reliability requirement is satisfied, one-shot transmission (i.e., single (TTI) allocation) is ideal. However, a target BLER of 1E-6 is not always achieved by one-shot transmission. Therefore, a retransmission or repetition mechanism is required.

[0029] In NR Rel.15, when one-shot transmission is not sufficient, both retransmission and repetition are supported to achieve the target BLER. HARQ-based retransmission is well-known for improving the overall reliability by utilizing feedback information and improving subsequent retransmissions according to the channel state. However, they suffer from additional delay due to the feedback processing timeline. Therefore, repetition is useful for delay-tolerant services as it performs subsequent transmissions of the same transport block without waiting for feedback.

[0030] PUSCH repetition can be defined as "transmitting the same transport block more than once without waiting for the feedback of the previous transmission of the same transport block". The advantage of PUSCH retransmission is the improvement in overall reliability and reduction in delay compared to HARQ as it does not require feedback. However, in general, link adaptation is not possible and resource utilization can be inefficient.

[0031] In NR Rel.15, limited support for repetition is introduced. Only semi-static configuration of repetition is possible. Also, repetition is only possible between slots (slot-level PUSCH repetition). Repetition is only possible in the slot following the slot of the previous transmission. Depending on the numerology and service type (e.g., URLLC, eMBB), the delay between repetitions can be too long for slot-level repetition.

[0032] Such repeated limited support is mainly useful for PUSCH mapping type A. This PUSCH mapping type A only allows PUSCH transmissions to start from the beginning of a slot. By repetition, this results in the first PUSCH transmission, and each repetition starts at the beginning of a plurality of consecutive slots.

[0033] The repeated limited support for PUSCH mapping type B is not very useful. PUSCH mapping type B allows PUSCH transmissions to start at any symbol within a slot. By repetition, this results in the first PUSCH transmission, and each repetition starts at the same symbol within a plurality of consecutive slots within the slot.

[0034] In either case, such limited support may not be able to achieve the more stringent delay requirements in NR Rel.15, i.e., up to a 0.5 ms delay. This requires mini-slot repetition. Furthermore, the repeated limited support also does not utilize the advantages resulting from a transmission time interval (TTI) that contains fewer symbols than a slot, i.e., a mini-slot (a slot containing 14 symbols).

[0035] PUSCH Allocation Another area for potential enhancements is more generally related to the allocation of PUSCH within one slot or across multiple slots. In the following, a motivation is provided to support different PUSCH transmission allocations that can potentially enhance the uplink utilization to further improve the delay while meeting the reliability requirements to better satisfy the new requirements of NR URLLC.

[0036] To achieve the delay requirement for URLLC PUSCH transmission, if reliability is satisfied, one-shot transmission (i.e., single (TTI) allocation) is ideal again. However, the target user plane delay of 0.5 ms is not always achieved for simultaneous PUSCH transmissions. Therefore, enhancements to uplink allocation are required.

[0037] In NR Rel.15, uplink scheduling is restricted to a single uplink grant per TT1. In the case of a single PUSCH transmission, this scheduling constraint is not a limitation, and the target user plane delay may be achieved via one-shot transmission. However, for simultaneous PUSCH transmissions, the scheduling constraint results in the possibility that one-shot transmission may not be sufficient to meet the target user plane delay.

[0038] In particular, simultaneous PUSCH transmissions require separate uplink grants, which have to be signaled at consecutive TTIs and with a large scheduling overhead due to the scheduling constraint. Therefore, this scheduling constraint introduces unnecessary delay in the case of simultaneous PUSCH transmissions. Also, multiple mini-slot allocations of PUSCH within a slot are not possible either.

[0039] In any case, due to such scheduling constraints, it may not be able to achieve the more stringent delay requirement in NR Rel.15, i.e., a delay of up to 0.5 ms. This may require mini-slot allocation of PUSCH. Furthermore, the limited support for PUSCH allocation does not utilize the advantages arising from transmission time intervals (TTIs) that contain fewer symbols than a mini-slot, i.e., a slot (a slot containing 14 symbols).

[0040] The First General Scenario In view of the above, the inventors of the present disclosure recognize that there is a need for a more flexible support for PUSCH transmissions, i.e., a mechanism that is not limited to PUSCH transmissions that require separate uplink grants.

[0041] At the same time, higher flexibility should not be obtained at the expense of additional signaling overhead. In other words, the inventors of the present disclosure recognize that flexible support for PUSCH transmissions does not require modification to the current uplink scheduling mechanism, i.e., the current format of uplink grants. In other words, for example, the signaling mechanism in the form of DCI format 0-0 or 0-1 for carrying the uplink grant remains the same, thereby avoiding additional signaling overhead when scheduling PUSCH transmissions.

[0042] Thus, it is a basic understanding of the present disclosure that PUSCH transmissions are supported with flexible timing that does not incur additional signaling overhead.

[0043] In this context, such flexible timing support for PUSCH transmissions is recognized not only as a possibility to enhance the generality of the mechanism, but also as a necessity to avoid conflicts with, for example, dynamic changes to the slot format (UL / DL). This is evident from the implementation discussed under section 6.3.3 as "Option 4" of 3GPP TR 38.824 v2.0.1, "Study on physical layer enhancements for NR ultra-reliable and low latency case (URLLC)", which is incorporated herein by reference.

[0044] For illustration purposes, assume that the proposed mechanism is utilized by a semi-static grant-free (configured grant) uplink. At configuration time, the configured grant specifies consecutive symbols of a slot for a plurality of PUSCH transmissions. However, this specification may cause a conflict with dynamic changes to the slot format. For example, if the slot format specifies a change to one of the configured consecutive symbols from UL to DL, this triggers a conflict with the plurality of configured PUSCH transmissions.

[0045] However, recognizing the requirement for flexible timing support, the authors identified the substantial technical constraints arising from the current uplink scheduling mechanism, i.e., for the downlink control information (DCI) format 0-1 of NR Rel.15.

[0046] One possibility for carrying the uplink grant is the downlink control information (DCI) format 0-1. This format (e.g., DCI format 0-1) is generally understood as a non-fallback format for supporting SU-MIMO (Single-User Multiple Input Multiple Output) or MU-MIMO (Multi-User Multiple Input Multiple Output) in the uplink. In this regard, DCI format 0-1 includes an antenna port field that enables the consistency of antenna ports for PUSCH transmissions.

[0047] The antenna port can be defined such that "the channel over which the symbol on the antenna port is transmitted can be inferred from the channel over which another symbol on the same antenna port is transmitted" (see, for example, Section 4.4 of 3GPP Technical Specification TS 38.211 v.15.5.0 entitled "Physical channels and modulation (Release 15)"). The concept of the antenna port also extends to the front-loaded Demodulation Reference Signal (DMRS) included in PUSCH transmission.

[0048] For example, the first front-loaded DMRS configuration corresponding to Configuration Type 1 supports up to 4 orthogonal DMRS ports when single-symbol DMRS is used and up to 8 orthogonal DMRS ports when double-symbol DMRS is used. The second front-loaded DMRS configuration corresponding to Configuration Type 2 provides support for up to 6 orthogonal DMRS ports when single-symbol DMRS is used and up to 12 orthogonal ports when double-symbol DMRS is used. From the perspective of the receiver, the DMRS ports are quasi-co-located.

[0049] Effectively, the front-loaded DMRS configuration is designed to allow flexibility between single-symbol DMRS and double-symbol DMRS. In particular, Configuration Type 1 and Configuration Type 2 are designed not only to support the maximum length of each symbol for DMRS (e.g., maxLength = 2), but also to support a smaller number of symbols. This can be seen, for example, for Configuration Type 1 (e.g., dmrs-Type = 1) reproduced below from Section 7.3.1.1.2 of 3GPP Technical Specification TS 38.212 v.15.5.0, titled "Multiplexing and channel coding (Release 15)", which is incorporated herein by reference. For this Configuration Type 1, in the case of up to 2-symbol DMRS, not only can 8 DMRS ports be scheduled, but up to 4 DMRS ports can also be scheduled.

Table 1

[0050] The inventors of the present disclosure recognized that such a front-loaded DMRS configuration can impose substantial technical constraints when utilizing a single uplink grant of the DCI Format 0-1 for scheduling multiple PUSCH transmissions with flexible timing.

[0051] For example, assume that a single uplink grant schedules two PUSCH transmissions at flexible timings. In this case, it is generally understood that such two PUSCH transmissions generally require individual notification of the DMRS ports used. For a single uplink grant that includes only a single antenna port field, it is impossible to notify the individual DMRS ports used. Rather, it is only possible to carry one index value that defines one DMRS port for each of the DMRS configurations placed in front. Therefore, there is an ambiguity as to whether the notified DMRS port is used for the first or second transmission of the two PUSCH transmissions at flexible timings.

[0052] In other words, the authors of the present disclosure recognized that there is an ambiguity in that one index value carried in the antenna port field of a single uplink grant is associated with any one of a plurality of PUSCH transmissions.

[0053] Also, the authors recognized that a situation may occur where scheduling two PUSCH transmissions at flexible timings may lead to a conflict regarding the mapping of the DMRS placed in front in the PUSCH transmission.

[0054] For example, assume that a single uplink grant schedules two PUSCH transmissions at flexible timings, that is, with different lengths. In this case, it is generally understood that it is not always allowed for such two PUSCH transmissions to include both single-symbol and double-symbol DMRS. Rather, the length of the PUSCH transmission places a constraint on the number of symbols for the DMRS that can be carried therein. This introduces an ambiguity as to whether the number of symbols placed in front for the DMRS indicated by a single uplink grant is used for the first or second transmission of the two PUSCH transmissions at flexible timings.

[0055] In NR Rel.15, the demodulation reference signal for PUSCH is described in Section 6.4.1.1 of 3GPP Technical Specification TS 38.211 v.15.5.0, titled "Physical channels and modulation (Release 15)", which is incorporated herein by reference.

[0056] For mapping to physical resources, the position of the DMRS symbol is given by l, and the duration is given by l d Here, for example, l d is the duration between the first OFDM symbol of the slot of PUSCH mapping type A according to Tables 6.4.1.1.3-3 and 6.4.1.1.3-4 and the last OFDM symbol of the scheduled PUSCH resource of the slot, or l d is the duration of the scheduled PUSCH resource of PUSCH mapping type B according to Tables 6.4.1.1.3-3 and 6.4.1.1.3-4. The referenced tables are reproduced below.

Table 2

Table 3

[0057] According to such mapping of the DMRS symbol to PUSCH, it is allowed for any duration of the PUSCH resource where single-symbol DMRS is scheduled, while for double-symbol DMRS, in the case of mapping type A, when the duration of the scheduled PUSCH resource is 4 symbols or more (l that causes an undefined DRMS position for mapping type A in Table 6.4.1.1.3-4) d(see reference 4), and in the case of mapping type B, when the duration of the scheduled PUSCH resource is 5 symbols or more (causing an undefined DMRS position for mapping type A in Table 6.4.1.1.3-4) d <4 and d = is only allowed for (see reference 4).

[0058] In other words, the authors of the present disclosure recognized that there is again an ambiguity where one index value carried in the antenna port field of a single uplink grant is associated with any one of a plurality of PUSCH transmissions.

[0059] In summary, the present disclosure of the exemplary embodiments improves the support for the allocation of physical uplink shared channel (PUSCH) transmissions with flexible timing, facilitating accurate channel estimation using the demodulation reference signal (DMRS) carried therein.

[0060] FIG. 4 shows an exemplary communication system including a user equipment (UE) 410 and a base station (BS) 460 in a wireless communication network. Such a communication system may be a 3GPP system such as NR, LTE, and / or UMTS. For example, as shown in the figure, the base station (BS) may be a gNB (gNodeB, e.g., NR gNB) or an eNB (eNodeB, e.g., LTE gNB). However, the present disclosure is not limited to these 3GPP systems or any other systems.

[0061] Although the embodiments and exemplary implementations are described using some terms of 3GPP systems, the present disclosure is also applicable to any other communication systems, particularly any cellular, wireless, and / or mobile systems.

[0062] Rather, it should be noted that many assumptions are made here so that the underlying principles of the present disclosure can be explained in a clear and understandable manner. However, these assumptions should be understood as merely specific examples for illustrative purposes and should not limit the scope of the present disclosure. Those skilled in the art will recognize that the principles as described in the following disclosure and claims are applicable to different scenarios and methods not explicitly described herein.

[0063] The mobile terminal is called a user equipment (UE) in LTE and NR. This may be a mobile device such as a wireless phone, smartphone, tablet computer, or a USB (Universal Serial Bus) stick with the functionality of a user device. However, the term mobile device is not limited to this, and generally, the relay may have the functionality of such a mobile device, and the mobile device may also function as a relay.

[0064] The base station (BS) forms at least a part of a system of interconnected units such as, for example, a (central) baseband unit and different radio frequency units, which interface with different antenna panels or radio heads in a network for providing services to terminals. That is, the base station provides wireless access to the terminals.

[0065] Referring back to the figure, the user equipment 410 includes a processing circuit (or processor) 430 and a transmitter / receiver (or transceiver) 420 shown as separate constituent blocks in the figure. Similarly, the base station 460 includes a processing circuit (or processor) 480 and a transmitter / receiver (or transceiver) 470 shown as separate constituent blocks in the figure. The transmitter / receiver 420 of the user equipment 410 is communicatively coupled via a wireless link 450 to the transmitter / receiver 470 of the base station 460.

[0066] FIG. 5 and FIG. 6 each show an exemplary implementation according to a first general scenario of the constituent blocks of user equipment 410 and base station 460. The user equipment 410 of the exemplary implementation includes an uplink grant receiver 520-a, a time-domain resource determination processing circuit 530-a, a DMRS symbol number determination processing circuit 530-b, a DMRS port number processing circuit 530-c, and a PUSCH transmission transmitter 520-b.

[0067] Similarly, the base station 460 of the exemplary implementation includes a time-domain resource determination processing circuit 680-a, a DMRS symbol number determination processing circuit 680-b, a DMRS port number determination processing circuit 680-c for DMRS, an index value determination processing circuit 680-d, an uplink grant transmitter 670-a, and a PUSCH transmission receiver 670-b.

[0068] This disclosure is given under the assumption that the user equipment 410 performs multiple physical uplink shared channel (PUSCH) transmissions. In an exemplary use case, these PUSCH transmissions may carry repetitions of the same transport block, thereby resulting in multiple PUSCH repetitions including the first PUSCH transmission and at least one (subsequent) PUSCH repetition.

[0069] Even for PUSCH transmissions with flexible timing, this does not prevent the same from carrying repetitions of the same transport block. Consider a specific example where scheduled PUSCH transmissions have different lengths, i.e., occupy different numbers of symbols. Even then, if the modulation and coding scheme (MCS) is appropriately adjusted for each PUSCH transmission, the PUSCH transmissions can carry repetitions of the same transport block.

[0070] However, the present disclosure should not be understood as being limited only to the repetition of transport blocks. Thus, the present disclosure generally refers to PUSCH transmissions that have no restrictions on the transport blocks being carried there, i.e., no restrictions whatsoever. For example, when scheduled PUSCH transmissions are used in part for the repetition of transport blocks and one-shot transmissions, many alternative use cases are also conceivable.

[0071] Referring to FIG. 7, a sequence diagram is shown in which a user equipment (UE) performs a plurality of PUSCH transmissions according to a first general scenario, i.e., the user equipment 410 performs a plurality of PUSCH transmissions that do not include different numbers of symbols for the DMRS placed in front of it being carried there.

[0072] Having confirmed that the user equipment 410 performs a plurality of PUSCH transmissions, it receives a single (e.g., one) uplink grant (see, e.g., step 710 in FIG. 7). The uplink grant is suitable for scheduling a plurality of PUSCH transmissions. The uplink grant is received from a base station 460 that schedules transmissions on the uplink, i.e., on the physical uplink shared channel (PUSCH). For example, this reception operation may be performed by the UL grant receiver 520-a in FIG. 5.

[0073] The user equipment 410 receives an uplink grant that includes an antenna port field with an index value. This index value may be used for many purposes in the user equipment 410, for example, to notify the antenna port on which the PUSCH transmission is performed. In other words, this index value is utilized for the plurality of PUSCH transmissions scheduled by the uplink grant.

[0074] Regarding 3GPP terms, the described uplink grant including the antenna port field may mean the signaling of downlink control information (DCI) format 0-1. For a comprehensive description of DCI format 0-1, refer to section 7.3.1.1.2 of 3GPP technical specification TS 38.212 v.15.5.0, which is incorporated herein by reference. Further, since all PUSCH transmissions exclusively use a pre-configured port numbered 0, another (alternative) format for carrying dynamic uplink grants in the 3GPP system, namely DCI format 0-0, does not include the antenna port field.

[0075] Also, regarding 3GPP terms, the described uplink grant including the antenna port field may alternatively mean the signaling of the ConfiguredGrantConfig information element (IE). A comprehensive description of the ConfiguredGrantConfig IE is made in section 6.3.2 of 3GPP technical specification TS 38.331 v.15.5.0 titled "Radio Resource Control (RRC) protocol specification (Release 15)", which is incorporated herein by reference. As is clear from the ASN.1 notation, since it is included in a series of fields specified as optional for the IE, not all of the ConfiguredGrantConfig IEs necessarily include the antenna port field.

[0076] Based on the received uplink grant, the user equipment 410 determines the time-domain resources used for a plurality of PUSCH transmissions (see, for example, step 720 in FIG. 7). Generally, the time-domain resources determined for each PUSCH transmission should be understood as a plurality of consecutive symbols specified for uplink transmission. For example, this determination operation may be executed by the time-domain resource determination processing circuit 530-a.

[0077] More specifically, the determined time domain resources define the number (e.g., maximum or total) of PUSCH transmissions scheduled with an uplink grant and define the length (e.g., symbols) of each of the plurality of PUSCH transmissions. The time domain resources are pre - allocated by the base station 460 for use by the user equipment 410.

[0078] In an exemplary embodiment, the determined time domain resources may also define at least one, i.e., the first or all positions, of the plurality of PUSCH transmissions. Such positions may be defined, for example, with respect to a (relative) slot offset and an (absolute) symbol number that designates the start within the slot. Alternatively, such positions may be inferred (e.g., in the technical specifications) in the form of consecutive PUSCH transmissions, i.e., when the first symbol of a subsequent PUSCH transmission follows immediately after the last symbol of a preceding PUSCH transmission.

[0079] Notwithstanding, in the context of the present disclosure, it is sufficient that the user equipment 410 can (actually) determine the time domain resources to be used for a plurality of PUSCH transmissions based on the uplink grant received. In other words, the present disclosure is not limited to any of the following exemplary embodiments.

[0080] In other exemplary embodiments, the user equipment 410 may determine the time domain resources by referring to a radio resource control (RRC) configuration table. In particular, an indication for a specific row of this RRC configuration table may be notified via a dynamic or configured uplink grant, i.e., by referring to an index value from the time domain resource allocation area included in such a dynamic or configured uplink grant.

[0081] For the case of a dynamic uplink grant, the mechanism of this embodiment can be best summarized as follows.

[0082] The user equipment 410 receives the PUSCH config information element IE in the form of RRC signaling, that is, the PUSCH config IE is applicable to a specific bandwidth part. Then, the user equipment 410 sets a table defined by the PUSCH time domain resource allocation list IE carried in the received PUSCH config IE. This table includes rows each having a value indicating the PUSCH mapping type, a value K2 indicating the slot offset, and a value SLIV indicating the start and length indicators. Thereafter, the user equipment 410 receives DCI in the form of MAC signaling carrying a time domain resource allocation filled with the value of m, where the value of m provides the row index m + 1 to the RRC configuration table.

[0083] Thereby, the user equipment 410 can determine the time domain resources for at least one PUSCH transmission based on the number of slots carrying the received DCI, the value K2 indicating the slot offset, and the value SLIV indicating the start and length indicators included in the indexed row of the RRC configuration table.

[0084] The mechanism of this exemplary embodiment does not (explicitly) specify how the number of multiple PUSCH transmissions is conveyed to the user equipment 410. For this reason, different improvements to the mechanism are currently being actively discussed, all aiming to enable the user equipment 410 to (definitely) characterize the time domain resources for multiple PUSCH transmissions.

[0085] In one improvement of the exemplary embodiment, it is assumed that the DCI not only carries the time domain resource allocation field but also carries an (explicit) notification of the (total) number of PUSCH transmissions being scheduled by the base station 460.

[0086] With this notification of the number of PUSCH transmissions, the user equipment 410 can determine each time domain resource based on the assumption that the determined time domain resource for the first PUSCH transmission directly (continuously) follows the time domain resources for all subsequent PUSCH transmissions, where the total number thereof is notified.

[0087] In particular, the user equipment 410 may use the same parameters of the indexed rows of the RRC configuration table to determine not only the time domain resource of the first PUSCH transmission but also the time domain resources of all subsequent PUSCH transmissions such that they are arranged continuously in the time domain. For example, this means that all time domain resources have symbols of the same length and are arranged continuously within one slot or across multiple slots.

[0088] In another refinement of the exemplary embodiment, it is assumed that the PUSCH config information element IE carries not only the time domain resource allocation for a single PUSCH transmission but also such allocations for all subsequent PUSCH transmissions scheduled by the base station 460.

[0089] According to such a time domain resource allocation, the user equipment 410 can, for example, infer the total number of PUSCH transmissions from the number of individual time domain resource allocations included in the RRC configuration table. And through the index, the user equipment 410 can refer to the indexed rows of the RRC configuration table to infer the total number of PUSCH transmissions and determine the time domain resources for the same transmissions.

[0090] More specifically, the indexed rows of the RRC configuration table can include multiple SLIV values corresponding to individual time domain resource locations that are arranged within one slot or across multiple slots. Since each SLIV value indicates the start and length of the time domain resource with respect to a symbol, the time domain resources need not be arranged continuously in the time domain. Rather, the start and length of each time domain resource may be set independently.

[0091] In a further refinement of the exemplary embodiment, it is assumed that the user equipment 410 further (actively) adapts the time domain resource allocation notified from the base station 460 when determining the time domain resources. Such adaptation may be necessary to handle (or address) side effects resulting from dynamic reconfiguration of the underlying slot format (UL / DL).

[0092] In other words, all of the mechanisms described above are based on a time domain resource allocation that is semi-statically configured via the RRC (in advance). Also, not all possible slot formats can be reflected in advance. Therefore, a dynamically notified change in the slot format may require adaptation of the semi-statically configured time domain resource allocation, i.e., when determining the time domain resources available for (actual) PUSCH transmission.

[0093] One possibility for conflict can arise from the signaling of the changed slot format that designates the symbols of the slot that change from UL to DL. If this symbol was previously intended to be used as part of the notified time domain resource allocation, the designated change of it from UL to DL will result in a conflict that needs to be handled (or addressed) on the user equipment side.

[0094] Such a conflict may be resolved by the user equipment shifting the notified time domain resource allocation so that the determined time domain resources occupy only the newly designated UL symbols of the slot.

[0095] Other possibilities of conflict may arise from the signaling of a modified slot format that specifies fewer symbols as UL and more symbols as DL. And even if the individual time domain resource allocation is not affected by the change in the slot format, a situation may occur where the notified time domain resource allocation is distributed over multiple slots. In particular, in the case where the signaling time domain resource allocation related to a single PUSCH transmission is distributed over multiple slots (crossing slot boundaries), since PUSCH transmissions crossing slot boundaries are not permitted, this will result in a conflict that needs to be reprocessed (or addressed) on the user equipment side.

[0096] Such a conflict may be resolved by the user equipment that segments the affected PUSCH transmission at the slot boundary into two (consecutive) PUSCH transmissions that no longer cross the slot boundary.

[0097] In particular, for this segmentation, the user equipment 410 has to send a larger number of PUSCH transmissions than those scheduled by the uplink grant.

[0098] For illustration, assume that the user equipment 410 receives an uplink grant scheduling three PUSCH transmissions. If one of these PUSCH transmissions is segmented by crossing the slot boundary, that one affected PUSCH transmission will actually result in two PUSCH transmissions, namely, one PUSCH transmission for the segment before the slot boundary and an additional one PUSCH transmission for the segment after the slot boundary. And the received uplink grant will cause the user equipment 410 to determine the time domain resources for a total of four PUSCH transmissions.

[0099] In summary, there are a plurality of possible implementations that enable determining time domain resources used for a plurality of PUSCH transmissions based on an uplink grant received by user equipment 410. Nevertheless, the present disclosure should not be understood as being limited to any of these exemplary implementations.

[0100] After determining time domain resources for (presumably more) PUSCH transmissions based on the received uplink grant, user equipment 410 configures PUSCH transmissions for those subsequent transmissions. Each PUSCH transmission includes at least one demodulation reference signal (DMRS) placed in front to enable coherent demodulation of the PUSCH transmission.

[0101] In this context, user equipment 410 determines (e.g., see step 730 in FIG. 7) the number of symbols (e.g., single symbol or double symbol) used for the DMRS placed in front of each PUSCH transmission. For this purpose, user equipment 410 determines the number of symbols based on the received index value carried in the antenna port field of a single uplink grant. For example, this determination operation may be performed by a DMRS symbol number determination processing circuit 530 - b.

[0102] It is emphasized that the present disclosure focuses on the fact that situations are allowed where different numbers of symbols are used for each of the DMRs placed in front. That is, the present disclosure considers not only situations where only single - symbol DMRS can be used as the DMRS placed in front, but instead situations where both single - symbol and double - symbol DMRS are available (allowed) as the DMRS placed in front.

[0103] Generally, when comparing with single-symbol DMRS, it is understood that double-symbol DMRS enables higher accuracy of channel estimation to be performed. This facilitates achieving better results for coherent demodulation of PUSCH transmissions. In particular, double-symbol DMRS has been introduced motivated by dealing with high time-varying and / or frequency-selective radio channels. Furthermore, double-symbol DMRS is also recognized to provide excellent detection results for PUSCH transmissions scheduled by a set grant, i.e., avoiding misdetection.

[0104] Nevertheless, the use of such a larger number of symbols for the DMRS placed ahead comes at the expense of a throughput reduction per PUSCH transmission. When a PUSCH transmission is scheduled with a certain length, the decision of whether to use double-symbol DMRS or not can reduce the symbols capable of carrying the payload in the form of a transport block. Therefore, this decision is left to the base station, i.e., under a given radio channel condition, it is up to the base station to determine whether the user equipment needs to use double-symbol DMRS for a PUSCH transmission or whether it is sufficient to use single-symbol DMRS for the same PUSCH transmission.

[0105] There are two different steps before the user equipment 410 actually knows whether to use double-symbol DMRS or single-symbol DMRS for a particular PUSCH transmission.

[0106] In the first step, the user equipment 410 is signaled a notification indicating whether the use of a different number of symbols is (generally) allowed for PUSCH transmissions. This notification is used later when determining the (actual) number of symbols to be used as the DMRS placed ahead included in each PUSCH transmission.

[0107] For example, this notification can configure the user equipment 410 (e.g., in the case of "Yes") such that either double-symbol or single-symbol DMRS can be used for all subsequent PUSCH transmissions. In other words, this configuration simply defines the (overall) availability of double-symbol DMRS for PUSCH transmissions. It does not require the double-symbol DMRS to be actually used. In addition to this specific example, the notification may configure the user equipment 410 (e.g., in the case of "No") such that only single-symbol DMRS can be used for PUSCH transmissions.

[0108] In a second step, the user equipment determines the (actual) number of symbols used for each of the DMRSs placed in front of a plurality of PUSCH transmissions. This determination is based on the index value carried in the antenna port field included in the received uplink grant. In this regard, since the index value is carried in the received uplink grant, it is directly linked to each of the PUSCH transmissions.

[0109] In an exemplary implementation, the user equipment 410 is provided with a configuration that defines the maximum number of symbols that are permitted to be used as the DMRS placed in front. When the maximum number of symbols is 2, the use of either double-symbol DMRS or single-symbol DMRS is permitted.

[0110] In another exemplary embodiment, the user equipment 410 determines the number of symbols used for the DMRS placed in front of each of the plurality of PUSCH transmissions. For this purpose, the user equipment 410 refers to the setting of its maximum number of symbols and, based on this, for example, when maxLength = 2, selects the corresponding table such as Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0 as described above. Then, the user equipment 410 uses the index value received from the antenna port field of the uplink grant to determine the corresponding indexed row of the selected table, and extracts from the fourth column of this indexed row the number of symbols used for each of the DMRS placed in front of the plurality of PUSCH transmissions.

[0111] Here, it is emphasized that the present disclosure focuses on the fact that the PUSCH transmissions have different lengths, that is, the time domain resources determined based on the uplink grant define different lengths for at least two of the plurality of PUSCH transmissions.

[0112] Under this state, it is recognized that the correct functioning of the scheduling of the plurality of PUSCH transmissions can no longer be ensured. Rather, if the determined uplink resources define PUSCH transmissions of different lengths, since it does not distinguish between individual PUSCH transmissions, it cannot be guaranteed that the determined (single) number of symbols is suitable for defining the use of the DMRS for each of the (plural) PUSCH transmissions having different lengths.

[0113] In an exemplary implementation, the user equipment 410 uses a determined (single) number of symbols to select, for example, as described above, the corresponding table for PUSCH mapping, the determined number of symbols of "1" in Table 6.4.1.1.3-3 of TS 38.211 v.15.5.0, and the determined number of symbols of "2" in Table 6.4.1.1.3-4 of TS 38.211 v.15.5.0 when intra-slot frequency hopping is not possible. From these tables, the user equipment 410 estimates the position of the DMRS in each PUSCH.

[0114] If these PUSCH transmissions do not have the same (single) length and instead have two different lengths, a situation can occur where the mapping of the DMRS, i.e., its position in each PUSCH transmission, is undefined (or unspecified, non-compliant).

[0115] This is directly obtained from the observation that the length (or duration) of the PUSCH transmission (the first column of the above table) determines the position of the DMRS in the PUSCH transmission (the second to ninth columns of the above table). And for a shorter length (or duration) of the PUSCH transmission, a specific mapping of the double-symbol DMRS is not defined. And the ambiguity between a (single) index value and PUSCH transmissions of different lengths can, in the worst case, result in an undefined (or unspecified, non-compliant) mapping of the DMRS for PUSCH transmissions of different lengths.

[0116] From this, it can be recognized that the correct functioning of the scheduling of multiple PUSCH transmissions cannot be ensured when different numbers of symbols (or double-symbols) of DMRS are allowed and the scheduled PUSCH transmissions have different lengths.

[0117] To ensure the correct functioning of the scheduling of multiple PUSCH transmissions, the user equipment 410 transmits the same (determined) or fewer PUSCH transmissions using the same (specified) or a portion of the time domain resources of the received uplink grant (see, for example, 740 in FIG. 7). Specifically, this transmission operation is performed such that none of the at least one preposed DMRS to be configured uses a different number of symbols. For example, this transmission operation may be performed by the PUSCH transmission transmitter 520-b.

[0118] Even with the focus of the present disclosure on situations where multiple PUSCH transmissions have different lengths, the user equipment 410, due to the constraint that a different number of symbols is not used for any of the at least one preposed DMRS to be configured, solves the situation where the correct functioning of PUSCH scheduling cannot be ensured by transmitting the same number or fewer PUSCH transmissions. This is the solution for the first general scenario.

[0119] In other words, instead of the user equipment operating under conditions where a different number of symbols is allowed to be used for each of the preposed DMRS and the received uplink grant is processed for the same purpose, i.e., to allow further use of the DMRS with a different number of symbols (e.g., due to the user equipment explicitly resulting in maxLength = 2 in Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0), it is explicitly required that the user equipment 410 transmits only PUSCH transmissions that do not include preposed DMRS using a different number of symbols. This resolves the ambiguity between the (single) uplink grant signaling from the base station and the corresponding transmissions of the (multiple) PUSCH transmissions.

[0120] In an exemplary embodiment, the user equipment 410 determines the number of symbols used for each of at least one front-loaded DMRS based on all different lengths of a plurality of PUSCH transmissions. For example, this not only determines the (single) number of symbols based on the index value received by the user equipment 410, but also compares the (e.g., maximum) number of symbols required for each of the PUSCH transmissions of different lengths with the (single) number to avoid an undefined (or unspecified, non-compliant) mapping of the DMRS to PUSCH transmissions of different lengths. If the comparison indicates a conflict, the user equipment 410 needs to re-determine the number of symbols being (currently) used based on all different lengths of the plurality of PUSCH transmissions.

[0121] The above description has been given from the perspective of the user equipment 410. However, this should not be understood as a limitation to the present disclosure. The base station 460 equally implements the first general scenario disclosed herein.

[0122] Again, consider the assumption that the base station 460 schedules a plurality of physical uplink shared channel (PUSCH) transmissions. In an exemplary use case, these PUSCH transmissions may carry repetitions of the same transport block, thereby resulting in a plurality of PUSCH repetitions including an initial PUSCH transmission and at least one (subsequent) PUSCH repetition.

[0123] Referring to FIG. 8, a sequence diagram of a base station (BS) that receives a plurality of PUSCH transmissions is shown in a first general scenario, i.e., when the base station 460 receives a plurality of PUSCH transmissions that do not include different numbers of symbols for the front-loaded DMRS carried therein.

[0124] In this context, the base station 460 determines time-domain resources (see, for example, step 810 in FIG. 8), and the determined time-domain resources define the number of a plurality of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions. For example, this determination operation may be performed by the time-domain resource determination processing circuit 680-a.

[0125] The base station 460 determines the number of symbols used for each of at least one pre-placed DMRS included in a plurality of PUSCH transmissions (see, for example, step 820 in FIG. 8), and the determined number of symbols is one of a smaller number and a larger number of symbols. For example, this determination operation may be performed by the DMRS symbol number determination processing circuit 680-b.

[0126] If at least two of the plurality of PUSCH transmissions have different lengths and at least one of the at least two of the plurality of PUSCH transmissions cannot include a larger number of symbols for each of the at least one pre-placed DMRS, the base station 460 determines an index value related to the smaller number of symbols from the determined number of symbols used for each of the at least one pre-placed DMRS included (again, see step 820 in FIG. 8). For example, this determination operation may be performed by the index value determination processing circuit 680-d.

[0127] Thereafter, the base station 460 transmits a single uplink grant based on the time-domain resources determined for the plurality of PUSCH transmissions (see, for example, step 830 in FIG. 8), and the single uplink grant includes an antenna port field with the determined index value used for the plurality of PUSCH transmissions. For example, this transmission operation may be performed by the uplink grant transmitter 670-a.

[0128] Then, the base station 460 receives a plurality of PUSCH transmissions using the determined time-domain resources (see, e.g., step 840 of FIG. 8), and each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed in front.

[0129] For simplicity, the operation of the base station is kept fairly short. However, this should not be understood as a limitation. Rather, those skilled in the art will readily understand that the same or similar considerations as those explicitly described for the user equipment apply equally in the operation of the base station, i.e., when the base station schedules a plurality of PUSCH transmissions using a single uplink grant.

[0130] Also, it is recognized here that the correct functionality of scheduling a plurality of PUSCH transmissions can no longer be ensured.

[0131] Therefore, when determining an index value related to a smaller number of symbols from the determined number of symbols used for each of the at least one front-placed DMRS included in the base station 460, resolving this situation (when the correct functionality of PUSCH scheduling cannot be ensured) is the solution for the first general scenario.

[0132] Thereby, the base station 460 can ensure that it receives the same number or a smaller number of PUSCH transmissions due to the constraint that the same determined number of symbols are not used for any of the at least one front-placed DMRS included.

[0133] The first exemplary implementation The following first exemplary implementation is provided to give a more detailed description of the operation of the user equipment 410 in the case of a first general scenario, that is, when the user equipment 410 performs a plurality of PUSCH transmissions that do not include different numbers of symbols for the DMRS placed in front to which it is transported. Reference is made to FIG. 9 showing a sequence diagram of the user equipment 410 performing a plurality of PUSCH transmissions according to a first exemplary implementation of the first general mechanism.

[0134] This description is given under the assumption that different numbers of symbols (e.g., maxLength = 2) are allowed to be used for each of the DMRSs placed in front. In other words, the present disclosure does not consider the situation where only single-symbol DMRSs are available (allowed) as the DMRSs placed in front, but instead considers the situation where both single-symbol and double-symbol DMRSs are available (allowed) as the DMRSs placed in front.

[0135] Upon confirming that the user equipment 410 performs a plurality of PUSCH transmissions, it receives a single (e.g., one) uplink grant (see, for example, step 910 in FIG. 9). The uplink grant is carried for scheduling a plurality of PUSCH transmissions. The uplink grant is received from the base station 460 that schedules transmissions on the uplink, that is, on the physical uplink shared channel (PUSCH).

[0136] Based on the received uplink grant, the user equipment 410 determines the time-domain resources to be used for the plurality of PUSCH transmissions (see, for example, step 920 in FIG. 9). Generally, the time-domain resources determined for each PUSCH transmission should be understood as a plurality of consecutive symbols designated for uplink transmission.

[0137] The present disclosure focuses again on a situation where a plurality of scheduled PUSCH transmissions have different lengths, that is, a situation where time domain resources determined based on an uplink grant define different lengths for at least two of the plurality of PUSCH transmissions.

[0138] In this context, the user equipment 410 determines (see, for example, step 930 in FIG. 9) the number of symbols (e.g., single symbol or double symbol) used for the DMRS placed in front of each PUSCH transmission. For this purpose, the user equipment 410 determines the number of symbols based on the received index value carried in the antenna port field of a single uplink grant.

[0139] For this purpose, the user equipment 410 illustratively refers to the setting of that maximum number of symbols and, based thereon, selects a corresponding table, e.g., Table 7.3.1.1.2 - 7 of TS 38.212 v.15.5.0 in this example where maxLength = 2 as described above. Then, the user equipment 410 uses the index value received from the antenna port field of the uplink grant to determine the corresponding indexed row of the selected table, and extracts from the fourth column of this indexed row the number of symbols used for each of the DMRS placed in front of the plurality of PUSCH transmissions.

[0140] Thereafter, the user equipment checks (see, for example, step 940 in FIG. 9) whether at least one of the at least two of the plurality of PUSCH transmissions can include a greater number of symbols for each of the at least one DMRS placed in front.

[0141] Therefore, the user equipment 410 uses the determined (single) number of symbols to select, as described above, the corresponding table for PUSCH mapping, for example, when intra-slot frequency hopping is not allowed, the determined number of symbols of "1" in Table 6.4.1.1.3-3 of TS 38.211 v.15.5.0, and when intra-slot frequency hopping is not allowed, the determined number of symbols of "2" in Table 6.4.1.1.3-4 of TS 38.211 v.15.5.0. From these tables, the user equipment 410 estimates the position of the DMRS in each PUSCH.

[0142] In particular, for different lengths (or durations) of each PUSCH transmission (the first column of the above table), the user equipment 410 determines whether the mapping or position of the DMRS in the PUSCH transmission (the second to ninth columns of the above table) is specified (in the case of "no" in step 940), or not specified (in the case of "yes" in step 940). This determination operation is based on the general understanding that a specific mapping of double-symbol DMRS is not specified (or not designated, non-compliant) for shorter lengths (or durations) of PUSCH transmission.

[0143] When it is confirmed that the determined number of symbols for the DMRS can result as a result for at least one of a plurality of PUSCH transmissions in the non-specified (in the case of "yes" in step 940) mapping (or position) of the DMRS, the user equipment tentatively selects at least one front-loaded DMRS with a smaller number of symbols (single-symbol DMRS) for all of the plurality of PUSCH transmissions (not explicitly shown in FIG. 9). However, this tentative selection of a smaller number of symbols may involve a change in the DMRS ports used and thus needs to be confirmed.

[0144] For this reason, the user equipment 410 checks whether the same DMRS port can be used with a smaller number of tentatively selected symbols used for at least one DMRS placed in front of all of the plurality of PUSCH transmissions (see, for example, step 950 in FIG. 9). In other words, the index value carried in the antenna port field determines not only the number of DMRS symbols but also the DMRS ports used for all PUSCH transmissions. Also, in order to avoid conflicts, it is necessary to ensure that the tentatively selected symbols are also available on the same DMRS port determined based on the index value.

[0145] For this, the user equipment 410 correspondingly refers, by way of example, to Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0 as described above again in the case of maxLength = 2 for the correspondingly selected table. From this table, the user equipment 410 determines the DMRS port (see, for example, the third column of the same table) notified by the index value (see, for example, the first column of the same table) carried in the antenna port field of the received uplink grant. Thereafter, the user equipment checks whether the tentatively selected smaller number of symbols (single-symbol DMRS) are also available on the same DMRS port (see DMRS ports 0 to 3 in the second to fifth rows of the same table), that is, with the same DMRS port number.

[0146] If the check is affirmative (in the case of "yes" in step 950), the user equipment 410 has confirmed that even if a different smaller number of symbols are selected, the smaller number of symbols are available for at least one DMRS placed in front of all of the plurality of PUSCH transmissions on the same DMRS port that is expected to be received by the base station 460 via the uplink grant for PUSCH transmission.

[0147] In this regard, when selecting at least one DMRS placed in front, the user equipment 410 · Fewer symbols are used, · Ensure that the same DMRS port number is used, For all of the plurality of PUSCH transmissions, select at least one DMRS placed ahead. Here, the DMRS port number used for all of the at least one DMRS placed ahead is the same as the DMRS port number associated with the received index value.

[0148] This result is illustrated in FIGS. 11 to 13.

[0149] For example, according to Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0, for the antenna port mapping of the DMRS configuration type with the maximum length of 2 symbols, when any of the index values 4, 5, 6, or 7 associated with the 2-symbol length DMRS is notified, the corresponding possible index values associated with the 1-symbol length DMRS and available are 0, 1, 2, or 3, respectively.

[0150] Furthermore, when the confirmation is negative (in the case of "no" in step 950), the user equipment 410 is confirming that the temporarily selected fewer different symbols cannot be used. These temporarily selected fewer symbols cannot be used via the same DMRS port as the DMRS port determined based on the index value. In other words, for a plurality of PUSCH transmissions, this requires that different DMRS ports be used.

[0151] That is, the DMRS port notified via the uplink grant and expected by the base station 460 to receive the PUSCH transmission cannot be used together with the fewer symbols temporarily selected for the DMRS.

[0152] In this regard, when selecting at least one DMRS placed ahead, the user equipment 410 · cannot include a greater number of symbols for each of at least one front-loaded DMRS, · cannot use the same DMRS port number as the DMRS port number associated with the received index value, Omit at least one PUSCH transmission from a plurality of PUSCH transmissions (see, for example, step 970 in FIG. 9).

[0153] Then, the user equipment 410 transmits a smaller number of PUSCH transmissions for the remainder of the plurality of PUSCH transmissions that are not omitted, such that a greater number of symbols and the same DMRS port number are used (see, for example, step 980 in FIG. 9).

[0154] In summary, the user equipment 410 transmits the same number (see the case of "yes" in step 950) or a smaller number (see the case of "no" in step 950) of PUSCH transmissions using the same or a part thereof determined based on the received uplink grant. In particular, this transmission is performed such that at least one front-loaded DMRS does not use a different number of symbols.

[0155] The above description of the first exemplary implementation is given from the perspective of the user equipment 410. However, this is not to be understood as a limitation of the present disclosure. The base station 460 equally executes the first exemplary implementation disclosed herein, i.e., the base station 460 receives a plurality of PUSCH transmissions that do not include a different number of symbols for the front-loaded DMRS carried therein.

[0156] Reference is made to FIG. 10, which shows a sequence diagram of the base station 460 that schedules a plurality of PUSCH transmissions according to the first exemplary implementation of the first general mechanism. In an exemplary use case, these PUSCH transmissions may carry repetitions of the same transport block, thereby resulting in a plurality of PUSCH repetitions including the first PUSCH transmission and at least one (subsequent) PUSCH transmission.

[0157] In this context, the base station 460 determines a time domain resource (see, for example, step 1010 in FIG. 10), and the time domain resource defines the number of a plurality of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions.

[0158] The present disclosure again focuses on a situation where a plurality of scheduled PUSCH transmissions have different lengths, that is, a situation where a time domain resource defines different lengths for at least two of the plurality of PUSCH transmissions.

[0159] The base station 460 determines the number of symbols used for each of at least one pre-positioned DMRS included in the plurality of PUSCH transmissions (see, for example, step 1020 in FIG. 10), and the determined number of symbols is one of a smaller number and a larger number of symbols.

[0160] Then, the base station 460 checks whether one of the number of PUSCH transmissions can include a larger number of symbols for each of at least one pre-positioned DMRS (see, for example, step 1030 in FIG. 10).

[0161] Therefore, the base station 460 utilizes the (single) determined number of symbols and selects the corresponding table of PUSCH mapping and, for example, as described above, when in-slot frequency hopping is not possible, the determined number of symbols of "1" in Table 6.4.1.1.3-3 of TS 38.211 v.15.5.0, and when in-slot frequency hopping is not possible, the determined number of symbols of "2" in TS 38.211 v.15.5.0. From these tables, the user equipment 410 estimates the position of the DMRS in each PUSCH.

[0162] In particular, for different lengths (or durations) of each PUSCH transmission (the first column of the above table), the base station 460 determines whether the mapping or position of DMRS in the PUSCH transmission (the second to ninth columns of the above table) is specified (in the case of "no" in step 1030) or not specified (in the case of "yes" in step 1030). This determination operation is based on the general understanding that a specific mapping of double-symbol DMRS is not specified (or not designated, non-compliant) for shorter lengths (or durations) of PUSCH transmission.

[0163] When it is confirmed that the number of symbols determined for DMRS occurs for at least one of the plurality of PUSCHs in the unspecified mapping (or position) of DMRS (in the case of "yes" in step 1030), the base station 460 selects at least one front-loaded DMRS with fewer symbols (single-symbol DMRS) for all of the plurality of PUSCH transmissions (not explicitly shown in FIG. 10).

[0164] When it is confirmed that the number of symbols determined for DMRS occurs for all of the plurality of PUSCHs in the specified mapping (or position) of DMRS (in the case of "no" in step 1030), the base station 460 selects at least one front-loaded DMRS with more symbols (single-symbol DMRS) for all of the plurality of PUSCH transmissions (not explicitly shown in FIG. 10).

[0165] Then, the base station 460 determines, for all of the plurality of PUSCH transmissions, that is, the index value associated with fewer symbols (for example, refer to step 1040 in FIG. 10) or the index value associated with more symbols (for example, refer to step 1050 in FIG. 10) used for each of the at least one front-loaded DMRS. The determined index value is also associated with the same DMRS port.

[0166] Thereafter, the base station 460 transmits a single uplink grant based on the time domain resources determined for the plurality of PUSCH transmissions (see, for example, step 1060 in FIG. 10), and the single uplink grant includes an antenna port field with the determined index values used for the plurality of PUSCH transmissions.

[0167] Also, the base station 460 receives the plurality of PUSCH transmissions using the determined time domain resources (see, for example, step 1070 in FIG. 10), and each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed in front.

[0168] For simplicity, the operation of the base station is kept quite short. However, this should not be understood as a limitation. Rather, those skilled in the art will readily understand that the same or similar considerations as those explicitly described for the user equipment apply equally in the operation of the base station, i.e., when the base station schedules a plurality of PUSCH transmissions with a single uplink grant.

[0169] Second general scenario Referring now to FIG. 14, a sequence diagram of a user equipment (UE) performing a plurality of PUSCH transmissions according to the second general scenario is shown, i.e., the user equipment 410 performs a plurality of PUSCH transmissions that may include a different number of symbols for the DMRS placed in front carried therein, but different DMRS port numbers are not used for any of them.

[0170] According to general understanding, DMRS ports need to be consistently used for the transmission and reception operations of multiple PUSCH transmissions. In other words, the DMRS placed in front of a PUSCH transmission needs to use a consistent DMRS port (e.g., the same DMRS port number) that is notified via an uplink grant and for which reception is expected. Without such consistency, the DMRS contained therein cannot contribute to accurate channel estimation and thus coherent demodulation at the receiving side, so the reception of multiple PUSCH transmissions will not succeed.

[0171] Therefore, the second general scenario facilitates avoiding such a mismatch in the case where multiple PUSCH transmissions are scheduled with different lengths and different numbers of symbols for DMRS (e.g., single-symbol or double-symbol DMRS) are allowed for the DMRS placed in front of it to be carried there.

[0172] When the user equipment 410 confirms to perform multiple PUSCH transmissions, it receives a single (e.g., one) uplink grant (see, for example, step 1410 in FIG. 14). The uplink grant is suitable for scheduling multiple PUSCH transmissions. The uplink grant is received from the base station 460 that schedules transmissions on the uplink, i.e., on the physical uplink shared channel (PUSCH). For example, this reception operation may be performed by the UL grant receiver 520-a in FIG. 5.

[0173] The user equipment 410 receives an uplink grant that includes an antenna port field with an index value. This index value may be used for many purposes in the user equipment 410, for example, to notify the antenna port on which the PUSCH transmission is performed. In other words, this index value is used for multiple PUSCH transmissions scheduled by the uplink grant.

[0174] Regarding 3GPP terms, the described uplink grant that includes an antenna port field may mean signaling of downlink control information (DCI) format 0-1. For a comprehensive description of DCI format 0-1, refer to section 7.3.1.1.2 of 3GPP technical specification TS 38.212 v.15.5.0, which is incorporated herein by reference. Further, another (alternative) format for carrying dynamic uplink grants in the 3GPP system, i.e., DCI format 0-0, does not include an antenna port field because all PUSCH transmissions exclusively use a preset port with number 0.

[0175] Also, regarding 3GPP terms, the described uplink grant that includes an antenna port field may alternatively mean signaling of the ConfiguredGrantConfig information element (IE). For a comprehensive description of the ConfiguredGrantConfig IE, refer to section 6.3.2 of 3GPP technical specification TS 38.331 v.15.5.0 titled "Radio Resource Control (RRC) protocol specification (Release 15)", which is incorporated herein by reference. As is apparent from the ASN.1 notation, not all of the ConfiguredGrantConfig IEs include an antenna port field because they are included in a series of fields designated as optional for the IE.

[0176] Based on the received uplink grant, user equipment 410 determines the time domain resources to be used for a plurality of PUSCH transmissions (see, e.g., step 1420 in FIG. 14). Generally, the time domain resources determined for each PUSCH transmission should be understood as a plurality of consecutive symbols designated for uplink transmission. For example, this determination operation may be performed by the time domain resource determination processing circuit 530-a.

[0177] More specifically, the determined time domain resources define the number (e.g., maximum number or total) of PUSCH transmissions scheduled by the uplink grant and define the length (e.g., symbols) of each of the plurality of PUSCH transmissions. The time domain resources are pre-allocated by the base station 460 for use by the user equipment 410.

[0178] In an exemplary implementation, the determined time domain resources may also define at least one, i.e., the first or all positions, of the plurality of PUSCH transmissions. Such positions may be defined, for example, with respect to a (relative) slot offset and the number of (absolute) symbols specifying the start within the slot. Alternatively, such positions may be inferred in the form of consecutive PUSCH transmissions (e.g., in the technical specification), i.e., the last symbol of a preceding PUSCH transmission directly precedes the first symbol of a subsequent PUSCH transmission.

[0179] Nevertheless, in the context of the present disclosure, it is sufficient that the user equipment 410 can (actually) determine the time domain resources used for the plurality of PUSCH transmissions based on the received uplink grant. In other words, the present disclosure is not limited to any of the exemplary implementations described above for the first general scenario.

[0180] All of the mechanisms described above are based on a semi-static time domain resource allocation set (in advance) via RRC. Also, not all possible slot formats can be reflected in advance. Therefore, a dynamically notified change in the slot format may be required for the adaptation of the semi-static time domain resource allocation, i.e., for determining the time domain resources actually available for PUSCH transmissions.

[0181] One possible source of contention could arise from the signaling of a modified slot format that specifies the symbols of the slot to be changed from UL to DL. If this symbol was previously intended to be used as part of the notified time domain resource allocation, its specified change from UL to DL would result in a contention that would need to be handled (or addressed) on the user equipment side.

[0182] Such contention may be resolved by the user equipment shifting the notified time domain resource allocation so that the determined time domain resources occupy only the newly specified UL symbols of the slot.

[0183] Another possible source of contention could arise from the signaling of a modified slot format that specifies fewer symbols of the slot as UL and more symbols as DL. And even if the individual time domain resource allocations are not affected by the change in the slot format, a situation may occur where the notified time domain resource allocations are spread across multiple slots. In particular, when the notified time domain resource allocation associated with a single PUSCH transmission is spread across multiple slots (crossing slot boundaries), since PUSCH transmissions across slot boundaries are not permitted, this would result in a contention that would need to be handled (or addressed) again on the user equipment side.

[0184] Such contention may be resolved by the user equipment segmenting the PUSCH transmission affected at the slot boundary into two (consecutive) PUSCH transmissions that no longer cross the slot boundary.

[0185] In particular, due to this segmentation, the user equipment 410 may need to transmit more PUSCH transmissions than those scheduled by the uplink grant.

[0186] For the sake of illustration, assume that the user equipment 410 receives an uplink grant that schedules three PUSCH transmissions. If one of these PUSCH transmissions is segmented by a slot boundary crossing, this affected PUSCH transmission actually results in two PUSCH transmissions, namely, one PUSCH transmission for the segment before the slot boundary and a further one PUSCH transmission for the segment after the slot boundary. And the received uplink grant will cause the user equipment 410 to determine time domain resources for a total of four PUSCH transmissions.

[0187] In summary, there are a plurality of possible implementations that enable the user equipment 410 to determine time domain resources to be used for a plurality of PUSCH transmissions based on the received uplink grant. Nevertheless, the present disclosure should not be understood as being limited to any of these exemplary implementations.

[0188] After determining the time domain resources for (presumably more) PUSCH transmissions based on the received uplink grant, the user equipment 410 configures PUSCH transmissions for those subsequent transmissions. Each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed ahead to enable coherent demodulation of the PUSCH transmission.

[0189] In this context, the user equipment 410 determines (see, for example, step 1430 in FIG. 14) the DMRS port number (for example, DMRS port numbers 0 to 7 for type 1 configuration, or DMRS port numbers 0 to 11 for type 2 configuration) to be used for the DMRS placed ahead of each PUSCH transmission. For this purpose, the user equipment 410 determines the DMRS port number based on the received index value carried in the antenna port field of a single uplink grant. For example, this determination operation may be performed by a DMRS port number determination processing circuit 530-c for DMRS.

[0190] This disclosure emphasizes the fact that it focuses on situations where different numbers of symbols are allowed to be used for each of the DMRSs placed in the front. In other words, this disclosure does not consider the situation where only single-symbol DMRS can be used (permitted) as the DMRS placed in the front. Instead, it considers the situation where both single-symbol and double-symbol DMRSs can be used (permitted) as the DMRS placed in the front.

[0191] There are two different steps before the user equipment 410 actually knows whether to use double-symbol DMRS or single-symbol DMRS for a specific PUSCH transmission. In the first step, the user equipment 410 is signaled a notification indicating whether the use of different numbers of symbols is (generally) permitted for the PUSCH transmission. This notification is used later when determining the (actual) number of symbols used as the DMRS placed in the front included in each of the PUSCH transmissions.

[0192] In an exemplary implementation, the user equipment 410 is provided with a configuration that defines the maximum number of symbols that are permitted to be used as the DMRS placed in the front. If the maximum number of symbols is 2, the use of either double-symbol DMRS or single-symbol DMRS is permitted.

[0193] In the second step, the user equipment determines the (actual) number of symbols used for each DMRS placed in the front of a plurality of PUSCH transmissions. This determination is based on the index value carried in the antenna port field included in the received uplink grant. In this regard, since the index value is carried in the received uplink grant, it is directly linked to each number of PUSCH transmissions.

[0194] The number of symbols allowed (see the first step described above) also affects the determination of the DMRS port number.

[0195] When different numbers of symbols are allowed for the DMRS placed in front, each of the different numbers of symbols needs to be combinable with a different DMRS port number and be separately notifiable from the base station 460 to the user equipment 410. For this reason, the index value carried within the uplink grant enables a clear notification of the (actual) number of symbols used for the DMRS placed in front for different numbers of allowed symbols.

[0196] At the same time, the index value not only notifies the (actual) number of symbols used for the DMRS placed in front, but rather notifies the combination of the number of symbols for the DMRS placed in front and the DMRS port numbers used for the DMRSs included in multiple PUSCH transmissions.

[0197] Here, when different numbers of symbols are allowed, only the index value efficiently achieves a clear notification of the (actual) number of symbols used when arranging different index values such that the same DMRS port number becomes a possible index for all of the different numbers of symbols allowed for the DMRS. Otherwise, the DMRS port is not available for both of the different numbers of allowed symbols.

[0198] In an exemplary implementation, the user equipment 410 determines a DMRS port number for each of the DMRSs placed in front of a plurality of PUSCH transmissions. For this purpose, the user equipment 410 refers to the configuration of the maximum number of symbols thereof, and based on this, for example, when maxLength = 2, as described above, it selects the corresponding table such as Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0. Then, the user equipment 410 uses the index value received from the antenna port field of the uplink grant to determine the corresponding indexed row of the selected table, and extracts from the third column of this indexed row the DMRS port number used for each of the DMRSs placed in front of the plurality of PUSCH transmissions.

[0199] Also, the influence of the number of symbols allowed can be seen in Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0, as described above. This table is devised for the case where different numbers of symbols are allowed, that is, when maxLength = 2. Therefore, each index value (the first column of the table) is clearly associated with the (actual) number of symbols used for the DMRS placed in front (the fourth column of the table). At the same time, each index value (the first column of the table) is also clearly associated with the DMRS port number (the third column of the table).

[0200] Furthermore, since different DMRS ports identified by numbers are available for the DMRSs placed in front of all different numbers of symbols, the different DMRS port numbers 0 - 3 may be used for both single-symbol DMRSs (see rows 2 - 5 of the table) and double-symbol DMRSs (see rows 6 - 9 of the table). Only DMRS port numbers 4 - 7 may be used for double-symbol DMRSs (see rows 10 - 13 of the table).

[0201] Therefore, the number of symbols allowed not only defines the table used, but also substantially affects the determination of the DMRS port numbers in that at least a part of the DRMS port numbers (e.g., DMRS port numbers 0 to 3 of the above-described table) can be indexed for each of two different index values, i.e., the (actual) number of symbols allowed.

[0202] Here, it is emphasized that the present disclosure focuses on the fact that multiple PUSCH transmissions have different lengths, i.e., the time domain resources determined based on the uplink grant define different lengths for at least two of the multiple PUSCH transmissions.

[0203] In this state, it is recognized that the correct function of scheduling multiple PUSCH transmissions can no longer be ensured. Rather, when the determined uplink resources define PUSCH transmissions of different lengths, since individual PUSCH transmissions are not distinguished, it cannot be guaranteed that the (single) number of determined symbols is suitable for defining the use of DMRS for each of the (multiple) PUSCH transmissions having different lengths.

[0204] In an exemplary embodiment, the user equipment 410 utilizes the (single) number of determined symbols to select the corresponding table for PUSCH mapping and, for example, as described above, when in-slot frequency hopping is not possible, the determined number of symbols of "1" in Table 6.4.1.1.3-3 of TS 38.211 v.15.5.0 and, when in-slot frequency hopping is not possible, the determined number of symbols of "2" in Table 6.4.1.1.3-4 of TS 38.211 v.15.5.0. From these tables, the user equipment 410 estimates the position of the DMRS in each PUSCH.

[0205] When multiple PUSCH transmissions do not have the same (single) length and have two different lengths, a situation can immediately occur where the mapping of DMRS, that is, its position in each PUSCH transmission, is undefined (or unspecified, non-compliant).

[0206] This is directly obtained from the observation that the length (or duration) of the PUSCH transmission (the first column of the above table) determines the position of the DMRS in the PUSCH transmission (the second to ninth columns of the above table). And a specific mapping of the double-symbol DMRS is not defined for the shorter length (or duration) of the PUSCH transmission. And the ambiguity between a (single) index value and PUSCH transmissions of (multiple) different lengths can, in the worst case, result in an undefined (or unspecified, non-compliant) mapping of the DMRS to PUSCH transmissions of different lengths.

[0207] From this, it can be recognized that the correct functioning of the scheduling of multiple PUSCH transmissions cannot be guaranteed under the condition that different numbers of symbols (or double-symbols) of DMRS are allowed and the scheduled PUSCH transmissions have different lengths.

[0208] To ensure the correct functioning of the scheduling of multiple PUSCH transmissions, the user equipment 410 transmits the same (specified) or fewer PUSCH transmissions using the same (determined) or a part of the time-domain resources of the uplink grant (see, for example, 1440 in FIG. 14). Specifically, this transmission operation is performed so that none of the at least one pre-placed DMRS included uses (multiple) different DMRS port numbers. For example, this transmission operation may be performed by the PUSCH transmission transmitter 520-b.

[0209] When the present disclosure focuses on the situation where multiple PUSCH transmissions have different lengths, the correct functioning of PUSCH scheduling can be ensured by a user equipment 410 that transmits the same number or fewer PUSCH transmissions, subject to the constraint that different determined DMRS port numbers are not used for any of the at least one preposed DMRS. This is the solution for the second general scenario to solve the situation.

[0210] It is allowed that different numbers of symbols are used for each preposed DMRS, and under the condition that the received uplink grant is processed for the same purpose, that is, even though it operates to allow further utilization of DMRS with different numbers of symbols (for example, explicitly for maxLength = 2, the user equipment in Table 7.3.1.1.2 - 7 of TS 38.212 v.15.5.0), the user equipment 410 is explicitly required to transmit only PUSCH transmissions that do not include preposed DMRS using different DMRS port numbers.

[0211] That is, this second general scenario attempts to achieve this purpose, that is, to allow further use of DMRS with different numbers of symbols, but recognizes that not all different numbers of symbols for which all different DMRS port numbers are allowed are available (for example, in Table 7.3.1.1.2 - 7 of TS 38.212 v.15.5.0, according to maxLength = 2, DMRS ports 0 to 3 are available with both single - symbol DMRS and double - symbol DMRS, and DMRS ports 4 to 7 are available only with double - symbol DMRS).

[0212] Therefore, for example, a situation can be prevented in which some of the multiple PUSCH transmissions with a larger number of symbols for DMRS are used for other multiple PUSCH transmissions with a smaller number of symbols for DMRS, using a DMRS port number (e.g., DMRS ports 0 to 3 in the above table) different from the DMRS port number (e.g., DMRS ports 4 to 7 in the above table). In other words, in this second general scenario, different numbers of symbols for DMRS are generally allowed among multiple PUSCH transmissions, but it is guaranteed that the same DMRS port is used for all of the multiple PUSCH transmissions corresponding to the DMRS port notified via the index value of the antenna port field carried in a (single) uplink grant.

[0213] Thereby, the ambiguity between the signaling of a (single) uplink grant from the base station and the corresponding transmission of (multiple) PUSCH transmissions can be resolved.

[0214] In an exemplary embodiment, the user equipment 410 determines the DMRS port number used for each of at least one pre-placed DMRS based on all different lengths of the multiple PUSCH transmissions. For example, this may require not only determining a (single) DMRS port number based on the index value received by the user equipment 410, but also comparing the (single) DMRS port number with the corresponding indexed symbol number by the (e.g., maximum) number of symbols required to avoid an undefined (or unspecified, non-compliant) mapping of the DMRS to PUSCH transmissions of different lengths for PUSCH transmissions of different lengths. If the comparison indicates a conflict, the user equipment 410 needs to re-determine the currently used DMRS port number based on all different lengths of the multiple PUSCH transmissions.

[0215] The above description is given from the perspective of the user equipment 410. However, this should not be understood as a limitation of the present disclosure. The base station 460 equally executes the second general scenario disclosed herein.

[0216] Again, the assumption that the base station 460 schedules multiple physical uplink shared channel (PUSCH) transmissions is noted. In an exemplary use case, these PUSCH transmissions may carry repetitions of the same transport block, thereby resulting in multiple PUSCH repetitions including the first PUSCH transmission and at least one (subsequent) PUSCH repetition.

[0217] Referring to FIG. 15, a sequence diagram of a base station (BS) receiving multiple PUSCH transmissions according to a second general scenario is shown, i.e., the base station 460 receives multiple PUSCH transmissions that do not include different DMRS port numbers of the DMRS placed in front thereof.

[0218] In this context, the base station 460 determines time domain resources (see, for example, step 1510 in FIG. 15), and the determined time domain resources define the number of multiple PUSCH transmissions and the length of each of the multiple PUSCH transmissions. For example, this determination operation may be performed by the time domain resource determination processing circuit 680-a.

[0219] The base station 460 determines the number of symbols used for each of at least one DMRS placed in front included in the multiple PUSCH transmissions (see, for example, step 1520 in FIG. 15), and the determined number of symbols is either a smaller number or a larger number of symbols. For example, this determination operation may be performed by the DMRS symbol number determination processing circuit 680-b.

[0220] In the case where at least two of the plurality of PUSCH transmissions have different lengths, and where at least one of the at least two of the plurality of PUSCH transmissions cannot include a greater number of symbols for each of the at least one pre-placed DMRS, the base station 460 determines an index value associated with the greater number of symbols from the determined number of symbols and a DMRS port number that is also available for at least one pre-placed DMRS with a smaller number of symbols determined, where the same DMRS port number is used (see step 1530 in FIG. 15). For example, this determination operation may be performed by the index value determination processing circuit 680-d.

[0221] In an exemplary implementation, when the base station 460 cannot include a greater number of symbols for DMRS in only a part of the PUSCH transmission, the use of DMRS ports 4 to 7 is prohibited and the use of DMRS ports 0 to 3 is permitted, and the base station 460 determines an index value from a table such as Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0 with maxLength = 2. Then, only the same DMRS port number is available together with the greater and smaller number of symbols without an unacceptable change in the DMRS port during the signaling of the number of PUSCH transmissions.

[0222] Importantly, since each of DMRS ports 0 to 3 can be notified via a different index value, the base station 460 determines an index value to correspond to a greater number of symbols of the number of symbols that still allows the mapping (or position) of the DMRS for each length of the plurality of PUSCH transmissions, for example, in accordance with Tables 6.4.1.1.3-3 and 6.4.1.1.3-4 of TS 38.211 v.15.5.0.

[0223] Thereafter, the base station 460 transmits a single uplink grant based on the time domain resources determined for a plurality of PUSCH transmissions (see, for example, step 1540 in FIG. 15), and the single uplink grant includes an antenna port field with a determined index value used for the plurality of PUSCH transmissions. For example, this transmission operation may be performed by the uplink grant transmitter 670-a.

[0224] Also, the base station 460 receives a plurality of PUSCH transmissions using the determined time domain resources (see, for example, step 1550 in FIG. 15), and each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed in front.

[0225] For simplicity, the operation of the base station is kept somewhat short. However, this is not to be understood as a limitation. Rather, those skilled in the art will readily understand that the same or similar considerations explicitly described for the user equipment find equal application in the operation of the base station when scheduling a plurality of PUSCH transmissions with a single uplink grant.

[0226] Also, it is recognized here that the correct functioning of scheduling a plurality of PUSCH transmissions can no longer be guaranteed.

[0227] Therefore, the base station 460 determines an index value associated with a larger number of symbols from the determined number of symbols, and a DMRS port number available for at least one DMRS placed in front by a smaller number of symbols with the same DMRS port number.

[0228] Thereby, the base station 460 can be guaranteed to receive the same number or a smaller number of PUSCH transmissions so that different DMRS port numbers determined for any of the included at least one DMRS placed in front are not used.

[0229] Second Exemplary Embodiment The following second exemplary embodiment is provided to give a more detailed description of the operation of the user equipment 410 according to the second general scenario, that is, the user equipment 410 performs a plurality of PUSCH transmissions that do not include different DMRS port numbers for the DMRS placed in front carried therein. Reference is made to FIG. 16 showing a sequence diagram of the user equipment 410 performing a plurality of PUSCH transmissions according to the second exemplary embodiment of the second general mechanism.

[0230] This description is given under the assumption that a different number of symbols are allowed to be used for each DMRS placed in front (for example, maxLength = 2). That is, the present disclosure does not consider the situation where only single-symbol DMRS is available (allowed) as the DMRS placed in front, but considers the situation where both single-symbol and double-symbol DMRS are available (allowed) as the DMRS placed in front.

[0231] Upon confirming that the user equipment 410 performs a plurality of PUSCH transmissions, it receives a single (for example, one) uplink grant (see, for example, step 1610 in FIG. 16). The uplink grant is carried to schedule a plurality of PUSCH transmissions. The uplink grant is received from the base station 460 that is scheduling transmissions on the uplink, that is, on the physical uplink shared channel (PUSCH).

[0232] Based on the received uplink grant, the user equipment 410 determines the time domain resources to be used for a plurality of PUSCH transmissions (see, for example, step 1620 in FIG. 16). Generally, the time domain resources determined for each PUSCH transmission are understood as the number of consecutive symbols specified for the uplink transmission.

[0233] The present disclosure again focuses on a situation where a plurality of scheduled PUSCH transmissions have different lengths, that is, a situation where time-domain resources determined based on an uplink grant specify different lengths for at least two of the plurality of PUSCH transmissions.

[0234] In this context, the user equipment 410 determines (e.g., refer to step 1630 in FIG. 16) the number of symbols (e.g., single symbol or double symbol) used for the DMRS placed in front of each PUSCH transmission. For this purpose, the user equipment 410 determines the number of symbols based on the received index value carried in the antenna port field of a single uplink grant.

[0235] For this purpose, the user equipment 410 exemplarily refers to the setting of that maximum number of symbols, and based on that, selects a corresponding table, e.g., in the case of maxLength = 2, Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0 as described above. Then, the user equipment 410 uses the index value received from the antenna port field of the uplink grant to determine the corresponding indexed row of the selected table, and extracts from the fourth column of the indexed row the number of symbols used for each DMRS placed in front of the plurality of PUSCH transmissions.

[0236] Thereafter, the user equipment checks (e.g., refer to step 1640 in FIG. 16) whether one or more of the plurality of PUSCH transmissions can include a larger number of symbols for each DMRS placed in front of at least one of them.

[0237] In this context, the term "a part" is understood to indicate a (specific) subset from all of the plurality of PUSCH transmissions. This term is used consistently throughout the remainder of this description. For example, a part of the plurality of PUSCH transmissions can be the (specific) third PUSCH transmission, and not the first and second PUSCH transmissions from a total of three PUSCH transmissions.

[0238] For this reason, the user equipment 410 utilizes the (single) number of determined symbols to select a corresponding table for PUSCH mapping, for example, as described above, when intra-slot frequency hopping is not allowed, the number of determined symbols of "1" in Table 6.4.1.1.3-3 of TS 38.211 v.15.5.0, and when intra-slot frequency hopping is not allowed, the number of determined symbols of "2" in Table 6.4.1.1.3-4 of TS 38.211 v.15.5.0. From these tables, the user equipment 410 estimates the position of the DMRS in each PUSCH.

[0239] In particular, the user equipment 410 determines whether the mapping or position of the DMRS in the PUSCH transmission (columns 2 to 9 in the above table) is specified (in the case of "no" in step 1640) or not specified (in the case of "yes" in step 1640) for different lengths (or durations) of each PUSCH transmission (the first column of the above table). This determination operation is based on the general understanding that a specific mapping of the double-symbol DMRS is not specified (or not designated, non-compliant) for a shorter length (or duration) of the PUSCH transmission.

[0240] When it is confirmed that the number of symbols determined for the DMRS occurs for one or more of the plurality of PUSCH transmissions in the unmapped (or position) of the DMRS (in the case of "yes" in step 1640), the user equipment tentatively selects at least one pre-placed DMRS with fewer symbols (single-symbol DMRS) for the part of the plurality of PUSCH transmissions (see above). However, since the tentative selection of fewer symbols may involve a change in the DMRS port used, it needs to be confirmed.

[0241] For this reason, the user equipment 410 checks whether the same DMRS port is available with the tentatively selected fewer symbols used for at least one pre-placed DMRS of one or more of the plurality of PUSCH transmissions (see above) (for example, see step 1650 in FIG. 16). That is, the index value carried in the antenna port field determines not only the number of DMRS symbols but also the DMRS port used for the part of the plurality of PUSCH transmissions. Also, to avoid conflicts, the number of tentatively selected symbols needs to be guaranteed to be available for the same DMRS port determined based on the index value.

[0242] Therefore, the user equipment 410 correspondingly selects the table. In this case where maxLength = 2 again, as described above, it illustratively refers to Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0. From this table, the user equipment 410 determines the DMRS port (e.g., refer to the third column of the same table) indicated by the index value carried in the antenna port field of the received uplink grant (e.g., refer to the first column of the same table). Then, the user equipment checks whether a smaller number of temporarily selected symbols (single-symbol DMRS) are also available with the same DMRS port (refer to DMRS ports 0 to 3 in the second to fifth rows of the same table), that is, with the same DMRS port number.

[0243] If the confirmation is affirmative (in step 1650, when it is "yes"), the user equipment 410 checks that even if a different smaller number of symbols are selected, these smaller number of symbols are notified via the uplink grant and are available for the DMRS placed in front of a part of the multiple PUSCH transmissions (refer to the above) via the same DMRS port through which the base station 460 is expected to receive the PUSCH transmission.

[0244] For the rest (or others) of the multiple PUSCH transmissions, the user equipment 410 tentatively selects the number of symbols corresponding to the number of symbols for the DMRS placed in front determined based on the received index value carried in the antenna port field of a single uplink grant. That is, for a PUSCH transmission that can include a larger number of symbols for the DMRS, it also uses a larger number of symbols notified in a single uplink grant.

[0245] Regarding this, when selecting at least one DMRS placed in front, the user equipment 410 · A smaller and a larger number of symbols are used for at least one DMRS placed in front, ·such that the same DMRS port number is used for fewer and more symbols, for all of the plurality of PUSCH transmissions, select at least one front-loaded DMRS, where the same DMRS port number used for all of the at least one front-loaded DMRSs is the same as the DMRS port number associated with the received index value.

[0246] This result is illustrated in FIGS. 18 to 20. For example, according to Table 7.3.1.1.2-7 of TS 38.212 v.15.5.0 for the antenna port mapping of the maximum length DMRS configuration type for two symbols, when any of the index values 4, 5, 6, or 7 associated with the 2-symbol length DMRS is signaled, the corresponding possible indices that are associated and available for the 1-symbol length DMRS are 0, 1, 2, or 3, respectively.

[0247] Furthermore, if the confirmation is negative (in the case of "no" in step 1650), the user equipment 410 has confirmed that the temporarily selected different fewer symbols cannot be used. These temporarily selected fewer symbols are not available on the same DMRS port as the DMRS port determined based on the index value. That is, for the plurality of PUSCH transmissions, this requires that different DMRS ports be used.

[0248] That is, the DMRS port notified via the uplink grant and expected by the base station 460 to receive the PUSCH transmission cannot be used with the temporarily selected fewer symbols for the DMRS.

[0249] In this regard, when selecting at least one front-loaded DMRS, the user equipment 410 · cannot include more symbols for each of the at least one front-loaded DMRSs, ·The same DMRS port number associated with the received index value cannot be used. Omit some PUSCH transmissions from multiple PUSCH transmissions (see above) (see step 1670 in FIG. 16 for example).

[0250] Then, the user equipment 410 transmits a smaller number of PUSCH transmissions for the remaining (or other) non-omitted PUSCH transmissions among the multiple PUSCH transmissions, such that a larger number of symbols and the same DMRS port number are used (see step 1680 in FIG. 16 for example).

[0251] In summary, the user equipment 410 transmits the same (determined) or a smaller number of PUSCH transmissions using the same (determined) time domain resources as those determined based on the received uplink grant or a part thereof (see the case of "yes" in step 1650). In particular, the transmission is performed such that none of the at least one pre-positioned DMRS uses different DMRS port numbers (plural).

[0252] The above description of the second exemplary implementation is given from the perspective of the user equipment 410. However, this should not be understood as a limitation to the present disclosure. The base station 460 equally executes the first exemplary implementation disclosed herein, that is, the base station 460 receives a plurality of PUSCH transmissions that do not include different DMRS port numbers for the pre-positioned DMRS carried therein.

[0253] Reference is made to FIG. 17 showing a sequence diagram of the base station 460 scheduling a plurality of PUSCH transmissions according to a second exemplary implementation of the first general mechanism. In an exemplary use case, these PUSCH transmissions may carry repetitions of the same transport block, thereby resulting in a plurality of PUSCH repetitions including the first PUSCH transmission and at least one (subsequent) PUSCH repetition.

[0254] In this context, the base station 460 determines time domain resources (see, e.g., step 1710 in FIG. 17), and the determined time domain resources define the number of a plurality of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions.

[0255] The present disclosure again focuses on a situation where a plurality of scheduled PUSCH transmissions have different lengths, that is, a situation where the time domain resources define different lengths for at least two of the plurality of PUSCH transmissions.

[0256] The base station 460 determines the number of symbols used for each DMRS placed in front of at least one of the plurality of PUSCH transmissions (see, e.g., step 1720 in FIG. 17), and the determined number of symbols is either a smaller number or a larger number of symbols.

[0257] Then, the base station 460 checks whether a part of the plurality of PUSCH transmissions can include a larger number of symbols for each DMRS placed in front of at least one of them (see, e.g., step 1730 in FIG. 17).

[0258] In this context, the term "a part" is understood to indicate a (specific) subset from all of the plurality of PUSCH transmissions. This term is used consistently throughout the remainder of this description. For example, a part of the plurality of PUSCH transmissions can be the (specific) third PUSCH transmission and not the first and second PUSCH transmissions from a total of three PUSCH transmissions.

[0259] Therefore, the base station 460 utilizes the determined number of (single) symbols to select the corresponding table for PUSCH mapping, and for example, as described above, when slot - inner frequency hopping is not allowed, the determined number of symbols of "1" in Table 6.4.1.1.3 - 3 of TS 38.211 v.15.5.0, and when slot - inner frequency hopping is not allowed, the determined number of symbols of "2" in Table 6.4.1.1.3 - 4 of TS 38.211 v.15.5.0. From these tables, the user equipment 410 estimates the position of the DMRS in each PUSCH.

[0260] In particular, the base station 460 determines whether the mapping or position of the DMRS in the PUSCH transmission (columns 2 - 9 in the above - mentioned table) is specified (in the case of "no" in step 1730) or not specified (in the case of "yes" in step 1730) for different lengths (or durations) of each PUSCH transmission (the first column of the above - mentioned table). This determination operation is based on the general understanding that a specific mapping of the double - symbol DMRS is not specified (or not designated, non - compliant) for shorter lengths (or durations) of PUSCH transmissions.

[0261] Upon confirming that the determined number of symbols for the DMRS occurs for a part of multiple PUSCH transmissions in the case of an unspecified mapping (or position) of the DMRS (in the case of "yes" in step 1730) (see the above), the base station 460 selects at least one front - placed DMRS with fewer symbols (single - symbol DMRS) for that part of the multiple PUSCH transmissions (see the above) (not explicitly shown in Figure 17).

[0262] After that, the base station 460 determines an index value associated with a larger number of symbols from the determined number of symbols, and when it is determined that some PUSCH transmissions that cannot include a larger number of symbols (see "yes" in step 1730), a DMRS port number that is also determined for at least one preposed DMRS with a smaller number of symbols with the same DMRS port number is determined (see, for example, step 1740 in FIG. 17).

[0263] Alternatively, the base station 460 determines, for each preposed DMRS included, an index value associated with a larger number of symbols and the same DMRS port used in all of the plurality of PUSCH transmissions.

[0264] After that, the base station 460 transmits a single uplink grant based on the time domain resources determined for the plurality of PUSCH transmissions (see, for example, step 1760 in FIG. 17), and the single uplink grant includes an antenna port field with the determined index value used for the plurality of PUSCH transmissions.

[0265] Also, the base station 460 receives a plurality of PUSCH transmissions using the determined time domain resources (see, for example, step 1770 in FIG. 17), and each PUSCH transmission includes at least one preposed demodulation reference signal (DMRS).

[0266] For simplicity, the operation of the base station is maintained somewhat shorter. However, this should not be understood as a limitation. Rather, those skilled in the art will find equal application in the operation of the base station, i.e., when it schedules a plurality of PUSCH transmissions with a single uplink grant, the same or similar considerations explicitly described for the user equipment.

[0267] The third general scenario According to the third general scenario, a user equipment and a base station that respectively execute and schedule a plurality of PUSCH transmissions based on a single uplink grant are proposed. The operations of the user equipment and the base station according to the third general scenario are not shown separately. They will be very similar to those shown in FIGS. 7 and 8 for the first general scenario. Nevertheless, their operations can be best understood from the following description.

[0268] The user equipment 410 receives a single uplink grant for a plurality of PUSCH transmissions. The single uplink grant includes an antenna port field with an index value used for the plurality of PUSCH transmissions. For example, this receiving operation may be performed by the uplink grant receiver 520-a.

[0269] Thereafter, the user equipment 410 determines time-domain resources based on the received uplink grant. The determined time-domain resources define the number of PUSCH transmissions and the length of each PUSCH transmission. Each PUSCH transmission includes at least one demodulation reference signal (DMRS) placed in front. For example, this determination operation may be performed by the time-domain resource determination processing circuit 530-b.

[0270] When a different number of symbols is allowed for each DMRS placed in front at least once, the user equipment 410 performs a specifically adapted transmission operation.

[0271] In particular, the user equipment 410 transmits the same number of PUSCH transmissions such that a smaller number of symbols is used according to the received index value for all of the DMRSs placed in front at least once, and does not transmit any of the plurality of PUSCH transmissions when the received index value is associated with a larger number of symbols than that used for the DMRS placed in front at least once. For example, this transmission operation may be performed by the PUSCH transmission transmitter 520-a.

[0272] Alternatively, the base station 460 determines time domain resources. The determined time domain resources define the number of multiple PUSCH transmissions and the length of each PUSCH transmission. For example, this determination operation may be performed by the time domain resource determination processing circuit 680-a.

[0273] When different numbers of symbols are allowed for each DMRS placed at least one ahead, the base station 460 performs a determination operation with specifically adapted index values.

[0274] In particular, the base station determines an index value associated with a smaller number of symbols such that the same number of PUSCH transmissions including a DMRS placed at least one ahead are received using a smaller number of symbols. For example, this determination operation may be performed by the index value determination processing circuit 680-d.

[0275] Then, the base station 460 transmits a single uplink grant based on the time domain resources determined for the multiple PUSCH transmissions. The single uplink grant includes an antenna port field with an index value used for the multiple PUSCH transmissions. For example, this determination operation may be performed by the uplink grant transmitter 670-a.

[0276] Also, the base station 460 receives multiple PUSCH transmissions using the determined time domain resources, and each PUSCH transmission includes a demodulation reference signal (DMRS) placed at least one ahead. For example, this reception operation may be performed by the PUSCH transmission receiver 670-b.

[0277] The present disclosure can be realized by software, hardware, or software operating in conjunction with hardware.

[0278] Each functional block used in the description of the above-described embodiments can be partially or entirely realized by an LSI such as an integrated circuit, and each process described in each embodiment may be partially or entirely controlled by the same LSI or a combination of LSIs.

[0279] The LSI may be formed as an individual chip, or alternatively, one chip may be formed to include some or all of the functional blocks. The LSI may include data input / outputs coupled thereto. Here, the LSI can be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the difference in integration density.

[0280] However, the technology for realizing the integrated circuit is not limited to LSI, and it may be realized using an application-specific circuit, a general-purpose processor, or an application-specific processor.

[0281] Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after manufacturing of an LSI or a reconfigurable processor in which the connection and setting of circuit cells arranged inside the LSI are reconfigurable may be used.

[0282] The present disclosure can be realized as digital processing or analog processing. As a result of the progress of semiconductor technology and other derivative technologies, when future integrated circuit technology replaces LSI, the functional blocks can be integrated using future integrated circuit technology. Biotechnology can also be applied.

[0283] The present disclosure can be realized by any type of device, apparatus, or system having a communication function, called a communication device.

[0284] Some non-limiting examples of such communication devices include telephones (e.g., mobile (cell) phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, remote health / telemedicine devices, and vehicles that provide communication capabilities (e.g., automobiles, airplanes, ships), as well as various combinations thereof.

[0285] The communication device is not limited to being portable or mobile, and may include any type of device, apparatus, or system that is non-portable or fixed, such as smart home devices (e.g., home appliances, lighting, smart meters, control panels), vending machines, and any other "things" in the network of the "Internet of Things (IoT)".

[0286] Communication may include, for example, exchanging data via cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0287] The communication device may also include devices such as a controller or sensor coupled to a communication device that performs the communication functions described in the present disclosure. For example, the communication device may include a controller or sensor that generates a control signal or data signal used by a communication device that performs the communication function of the communication device.

[0288] The communication device may also include an infrastructure facility such as a base station, access point, and any other device, apparatus, or system that communicates or controls with a device such as those in the above non-limiting examples.

[0289] According to a first aspect, there is provided a user equipment (UE) comprising: a receiver that, during operation, receives a single uplink grant for a plurality of PUSCH transmissions, the single uplink grant including an antenna port field with an index value used for the plurality of PUSCH transmissions; a processor that, during operation, determines time domain resources based on the received uplink grant, the determined time domain resources defining the number of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions; and a transmitter that, during operation, transmits the plurality of PUSCH transmissions using the determined time domain resources, each of the plurality of PUSCH transmissions including at least one demodulation reference signal (DMRS) placed in front. The processor determines, during operation, the number of symbols to be used for each of the at least one DMRS placed in front of the plurality of PUSCH transmissions based on the received index value. When at least two of the plurality of PUSCH transmissions have different lengths and different numbers of symbols are allowed for each of the at least one DMRS placed in front, the transmitter transmits the same or fewer PUSCH transmissions such that the determined different numbers of symbols are not used for any of the at least one DMRS included.

[0290] According to a second aspect provided in addition to the first aspect, the processor is configured to use, during operation, for each of the at least one DMRS placed in front, a maximum number of two symbols that allow the use of either a single-symbol DMRS with fewer one symbol or a double-symbol DMRS with more two symbols.

[0291] According to a third aspect provided in addition to either the first or the second aspect, the processor determines, during operation, the number of symbols to be used for each of the at least one DMRS placed in front based on all different lengths of the plurality of PUSCH transmissions.

[0292] According to a fourth aspect provided in addition to any one of the first to third aspects, when at least two of the plurality of PUSCH transmissions have different lengths, and at least one of the at least two of the plurality of PUSCH transmissions cannot include a larger number of symbols for each of the DMRSs placed in front of the at least one, when the processor determines the number of symbols used during operation, for all of the plurality of PUSCH transmissions, it selects the at least one DMRS placed in front with a smaller number of symbols, and the transmitter transmits the same number of PUSCH transmissions such that a smaller number of symbols are used for all of the at least one DMRS placed in front during operation.

[0293] According to a fifth aspect provided in addition to the fourth aspect, when at least one of the plurality of PUSCH transmissions during operation cannot include a larger number of symbols for the at least one DMRS placed in front, the processor selects, for all of the plurality of PUSCH transmissions, the at least one DMRS placed in front with the smaller number of symbols.

[0294] According to a sixth aspect provided in addition to either the fourth or fifth aspect, when the processor selects the at least one DMRS placed in front during operation, for all of the plurality of PUSCH transmissions, it selects the at least one DMRS placed in front such that the smaller number of symbols are used and the same DMRS port number is used, and the DMRS port number used for all of the at least one DMRS placed in front is the same as the DMRS port number associated with the received index value.

[0295] According to a seventh aspect provided in addition to any of the fourth to sixth aspects, when the processor selects the at least one front-mounted DMRS during operation, from the plurality of PUSCH transmissions, it cannot include a greater number of symbols for each of the at least one front-mounted DMRS, and omits at least one PUSCH transmission that cannot use the same DMRS port number as the DMRS port number associated with the received index value. The transmitter transmits a smaller number of the PUSCH transmissions such that the greater number of symbols and the same DMRS port number are used for all of the at least one front-mounted DMRS included during operation.

[0296] According to an eighth aspect, a user equipment (UE) includes a receiver that receives a single uplink grant for a plurality of PUSCH transmissions during operation, the single uplink grant including an antenna port field that includes an index value used for the plurality of PUSCH transmissions, a processor that determines time domain resources based on the received uplink grant during operation, the determined time domain resources defining the number of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions, and a transmitter that transmits the plurality of PUSCH transmissions using the determined time domain resources during operation, each of the plurality of PUSCH transmissions including at least one front-mounted demodulation reference signal (DMRS). The processor determines, based on the received index value during operation, the DMRS port number used for each of the at least one front-mounted DMRS of the plurality of PUSCH transmissions. When at least two of the plurality of PUSCH transmissions have different lengths and different numbers of symbols are allowed for each of the at least one front-mounted DMRS, the transmitter transmits the same number or a smaller number of PUSCH transmissions such that the determined different DMRS port numbers are not used for any of the at least one front-mounted DMRS included during operation. The UE is provided.

[0297] According to a ninth aspect provided in addition to the eighth aspect, the processor is configured to use a maximum of two symbols for each of the at least one front-mounted DMRS such that during operation, a DMRS port having a number between 0 and 7 is used for a type 1 configuration or a DMRS port having a number between 0 and 11 is used for a type 2 configuration.

[0298] According to a tenth aspect provided in addition to either the eighth or ninth aspect, the processor determines, during operation, the DMRS port number used for each of the at least one front-mounted DMRS based on all different lengths of the plurality of PUSCH transmissions.

[0299] According to an eleventh aspect provided in addition to any of the eighth to tenth aspects, the processor further determines, during operation, the number of symbols used for each of the at least one front-mounted DMRS of the plurality of PUSCH transmissions based on the received index value. When at least two of the plurality of PUSCH transmissions have different lengths and it is determined that different numbers of symbols are used for at least two of the plurality of PUSCH transmissions having different lengths, the processor selects, during operation, the same DMRS port number that is available for all of the plurality of PUSCH transmissions and for all of the at least one front-mounted DMRS, and the transmitter transmits the same number of PUSCH transmissions such that the same DMRS port number is used with the different numbers of symbols for all of the at least one front-mounted DMRS included during operation.

[0300] According to a twelfth aspect provided in addition to the eleventh aspect, when determining the DMRS port number during operation, the processor selects the DMRS port number such that for all of the plurality of PUSCH transmissions, a smaller number and a larger number of symbols are used for the at least one DMRS placed in front, and the same DMRS port number is used for the smaller number and the larger number of symbols, and the same DMRS port number used for all of the at least one DMRS placed in front is the same as the DMRS port number associated with the received index value.

[0301] According to a thirteenth aspect provided in addition to the twelfth aspect, when determining the DMRS port number during operation, the processor excludes at least one PUSCH transmission from the plurality of PUSCH transmissions that cannot include a larger number of symbols for each of the at least one DMRS placed in front and cannot use the same DMRS port number as the DMRS port number associated with the received index value, and the transmitter transmits the smaller number of PUSCH transmissions such that the larger number of symbols and the same DMRS port are used for all of the at least one DMRS placed in front.

[0302] According to a 14th aspect, a user equipment (UE) includes a receiver that, during operation, receives a single uplink grant for a plurality of PUSCH transmissions, where the single uplink grant includes an antenna port field with an index value used for the plurality of PUSCH transmissions; a processor that, during operation, determines time domain resources based on the received uplink grant, where the determined time domain resources define the number of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions; and a transmitter that, during operation, transmits the plurality of PUSCH transmissions using the determined time domain resources, where each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed in front. When different numbers of symbols are allowed for each of the at least one DMRS placed in front, the transmitter transmits the same number of PUSCH transmissions such that a smaller number of symbols are used according to the received index value for all of the at least one DMRS placed in front. When the received index value is associated with a larger number of symbols than those used for the at least one DMRS placed in front, the UE does not transmit any of the plurality of PUSCH transmissions.

[0303] According to a 15th aspect provided in addition to the 14th aspect, the processor is configured to use, for each of the at least one DMRS placed in front, a maximum number of 2 symbols that allow the use of either a single-symbol DMRS with a smaller number of 1 symbol or a double-symbol DMRS with a larger number of 2 symbols.

[0304] According to the 16th aspect, there is provided a base station (BS) including: a processor that determines time domain resources during operation, where the determined time domain resources define the number of a plurality of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions; a transmitter that transmits a single uplink grant based on the determined time domain resources for the plurality of PUSCH transmissions during operation, where the single uplink grant includes an antenna port field having an index value used for the plurality of PUSCH transmissions; and a receiver that receives the plurality of PUSCH transmissions using the determined time domain resources during operation, where each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed in front. The processor determines, during operation, the number of symbols used for each of the at least one DMRS placed in front included in the plurality of PUSCH transmissions, and the determined plurality of symbols are one of a smaller number and a larger number of symbols. When at least two of the plurality of PUSCH transmissions have different lengths and at least one of the at least two of the plurality of PUSCH transmissions cannot include a larger number of symbols for each of the at least one DMRS placed in front, the processor determines, during operation, the index value associated with a smaller number of symbols from the determined plurality of symbols used for each of the at least one DMRS placed in front, and the receiver receives the same number or a smaller number of PUSCH transmissions so that a different number of determined symbols are not used for any of the at least one DMRS placed in front during operation. A BS is provided.

[0305] According to a 17th aspect, there is provided a base station (BS) comprising: a processor that determines time-domain resources during operation, the determined time-domain resources defining a number of a plurality of PUSCH transmissions and lengths of respective ones of the plurality of PUSCH transmissions; a transmitter that transmits a single uplink grant based on the determined time-domain resources for the plurality of PUSCH transmissions, the single uplink grant including an antenna port field with an index value used for the plurality of PUSCH transmissions; and a receiver that receives the plurality of PUSCH transmissions using the determined time-domain resources, each of the plurality of PUSCH transmissions including at least one demodulation reference signal (DMRS) placed in front. The processor determines, during operation, a number of symbols used for each of the at least one DMRS placed in front included in the plurality of PUSCH transmissions, the determined number of symbols being one of a smaller number and a larger number of symbols. When at least two of the plurality of PUSCH transmissions have different lengths and different numbers of symbols are allowed for each of the at least one DMRS placed in front, the processor determines, during operation, the index value associated with the larger number of symbols from the determined number of symbols and a DMRS port number that the same DMRS port number can also be used for the at least one DMRS placed in front by the determined smaller number of symbols. The receiver receives the same number or a smaller number of PUSCH transmissions such that, during operation, the determined different DMRS port numbers are not used for any of the at least one DMRS placed in front included. A BS is provided.

[0306] According to the 18th aspect, there is provided a base station (BS) including: a processor that determines time-domain resources during operation, where the determined time-domain resources define the number of a plurality of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions; a transmitter that transmits a single uplink grant based on the determined time-domain resources for the plurality of PUSCH transmissions during operation, where the single uplink grant includes an antenna port field having an index value used for the plurality of PUSCH transmissions; and a receiver that receives the plurality of PUSCH transmissions using the determined time-domain resources during operation, where each of the plurality of PUSCH transmissions includes at least one demodulation reference signal (DMRS) placed in front. When different numbers of symbols are allowed for each of the at least one front-placed DMRS, the processor determines the index value associated with the smaller number of symbols such that the same number of PUSCH transmissions including the at least one front-placed DMRS are received using the smaller number of symbols during operation.

Claims

1. An integrated circuit for controlling the processing of a user equipment (UE), wherein the processing comprises: receiving a single uplink grant for a plurality of PUSCH transmissions, the single uplink grant including an antenna port field with an index value used for the plurality of PUSCH transmissions; determining time domain resources based on the received uplink grant, the determined time domain resources defining the number of PUSCH transmissions and the length of each of the plurality of PUSCH transmissions; transmitting the plurality of PUSCH transmissions using the determined time domain resources, each of the plurality of PUSCH transmissions including at least one demodulation reference signal (DMRS) placed in front; determining the number of symbols to be used for each of the at least one DMRS placed in front of the plurality of PUSCH transmissions based on the received index value; when at least two of the plurality of PUSCH transmissions have different lengths and different numbers of symbols are allowed for each of the at least one DMRS placed in front, transmitting the same or fewer PUSCH transmissions so that the determined different numbers of symbols are not used for any of the at least one DMRS placed in front.

2. The integrated circuit according to claim 1, configured to use a maximum number of 2 symbols that allow the use of either a single-symbol DMRS with fewer 1 symbol or a double-symbol DMRS with more 2 symbols for each of the at least one DMRS placed in front.

3. The integrated circuit according to claim 1, determining the number of symbols to be used for each of the at least one DMRS placed in front based on all different lengths of the plurality of PUSCH transmissions.

4. When at least two of the plurality of PUSCH transmissions have different lengths and at least one of the at least two of the plurality of PUSCH transmissions cannot include more symbols for each of the at least one DMRS placed in front, when determining the plurality of symbols to be used, select the at least one DMRS placed in front with fewer symbols for all of the plurality of PUSCH transmissions. For all of the at least one DMRS placed in front, perform the same number of PUSCH transmissions such that fewer symbols are used, and / or if at least one of the plurality of PUSCH transmissions cannot include more symbols than the at least one DMRS placed in front, select, for all of the plurality of PUSCH transmissions, the at least one DMRS placed in front having the fewer symbols. The integrated circuit according to claim 1. **Claim 5** When selecting the at least one DMRS placed in front, select the at least one DMRS placed in front such that the fewer symbols are used and the same DMRS port number is used for all of the plurality of PUSCH transmissions, and the DMRS port number used for all of the at least one DMRS placed in front is the same as the DMRS port number associated with the received index value, and / or when selecting the at least one DMRS placed in front, omit at least one PUSCH transmission from the plurality of PUSCH transmissions that cannot include more symbols than each of the at least one DMRS placed in front and for which the same DMRS port number as the DMRS port number associated with the received index value cannot be used, transmit fewer of the PUSCH transmissions such that the more symbols and the same DMRS port number are used for all of the at least one DMRS placed in front. The integrated circuit according to claim 4.

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