Method and apparatus for probing and control signaling enhancements

Abstract

In one embodiment, the User Equipment (UE) receives downlink control information (DCI) from the Access Node (AN) for the transmission of a Signal of Reference Signal (SRS) resource set that triggers the transmission of an SRS. The DCI indicates time-domain resources among the available time-domain resources for transmitting the SRS resource set. The UE determines the location of the time-domain resources within the available time-domain resources based on the DCI and transmits the SRS accordingly. In another embodiment, the UE receives control information indicating frequency resources in a carrier for transmitting one or more SRS. Based on this, the UE determines to divide the frequency resources into segments, each comprising a contiguous physical resource block (PRB), and transmits the SRS using Orthogonal Frequency Division Multiplexing (OFDM) symbols on the first segment, rather than the second segment.

Description

[0001] This application is a divisional application. The original application has the application number 202180071613.2 and the original application date is October 21, 2021. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to wireless communications, and in certain embodiments, to methods and apparatus for detecting and controlling signaling enhancements. Background Technology

[0003] The Sounding Reference Signal (SRS) is a reference signal transmitted by the User Equipment (UE) on the uplink to achieve uplink channel estimation over a wide bandwidth. Therefore, the network can communicate with the UE based on the uplink channel estimation. Furthermore, due to the channel reciprocity between the uplink and downlink in Time Division Duplex (TDD) communication systems, the network can utilize the SRS for dynamic scheduling. That is, the network can utilize channel-dependent scheduling. In this case, time-frequency resources are dynamically scheduled considering different traffic priorities and quality-of-service requirements. Typically, the UE monitors several Physical Downlink Control Channels (PDCCHs) to obtain scheduling decisions, which are then transmitted to the UE by the network. When a valid PDCCH is detected, the UE follows the scheduling decision and receives (or transmits) data.

[0004] The SRS-related parameters of the SRS to be transmitted in the uplink (such as SRS transmission port, SRS transmission bandwidth, SRS resource set, transmission comb, and cyclic shift) are essentially semi-statically configured and can be provided by higher-layer signaling such as Radio Resource Control (RRC) signaling. A more dynamic technique is needed to indicate the configuration to better correlate SRS parameters (such as SRS transmission bandwidth and / or port) with Physical Data Sharing Channel (PDSCH) parameters. Furthermore, it is desirable to transmit the association between downlink reference signals, such as Channel State Information Reference Signal (CSI-RS) or Demodulation Reference Signal (DMRS), and the uplink SRS to the UE to accurately reflect interference conditions and perform optimal beamforming. Therefore, an apparatus and method are needed for transmitting control information that accurately indicates a more dynamic (rather than semi-static) configuration of the aforementioned parameters, such as, for example, using a subset of transmission ports associated with a specific downlink reference signal set to transmit a portion of the required transmission bandwidth for a subset of the SRS resource set (thus implicitly indicating the transmission comb and cyclic shift). The transmission of control information can be closely linked to the actual data transmission. As configured by the Layer 3 RRC configuration signaling, SRS transmission can be periodic (i.e., periodic SRS, P-SRS, or P SRS), semi-persistent (i.e., semi-persistent SRS, SP-SRS, or SP SRS) as activated / deactivated by the Layer 2 MAC CE, or aperiodic (i.e., aperiodic SRS, A-SRS, AP-SRS, A SRS, or AP SRS) as indicated by the Layer 1 Downlink Control Information (DCI) in the PDCCH. Summary of the Invention

[0005] The present disclosure provides substantial technical advantages through the description of embodiments of methods and apparatus for detecting and controlling signaling enhancements.

[0006] According to one aspect of this disclosure, a method is provided, comprising: receiving downlink control information (DCI) from an access node (AN) for the transmission of a trigger probe reference signal (SRS) resource set, the DCI including first information indicating a first time-domain resource among available time-domain resources for transmitting the SRS resource set; determining available time-domain resources for transmitting the SRS resource set by the UE based on a first timeslot of the received DCI; determining the position of the first time-domain resource among the available time-domain resources by the UE based on the first information of the DCI; and transmitting the SRS to the AN based on the position of the first time-domain resource.

[0007] Optionally, in any of the above aspects, determining the available time domain resources includes: the UE determining a reference time slot for the available time domain resources based on the location of the first time slot of the DCI and the higher-layer parameter slotoffset; and the UE determining the location of the available time domain resources based on the reference time slot.

[0008] Alternatively, in any of the above aspects, the reference slot is the first slot in which the DCI is received when the higher-level parameter slotoffset is not configured.

[0009] Alternatively, in any of the above aspects, the reference slot is located n slots after the first slot, where n is configured by the higher-level parameter slotoffset, and n is greater than or equal to zero (0).

[0010] Alternatively, in any of the foregoing aspects, available time-domain resources include time-domain resources located in or after a reference time slot and configured as uplink (UL) or flexible, wherein the time-domain resources are in units of time slots, mini-time slots, or OFDM symbols.

[0011] Optionally, in any of the above aspects, DCI includes an index of the first time-domain resource in the available time-domain resources.

[0012] Optionally, in any of the above aspects, the method further includes: the UE determining that the transmission of SRS conflicts with another transmission / reception in the first time domain resource; and the UE transmitting SRS in the next time domain resource of the first time domain resource in the available time domain resources instead of transmitting SRS in the first time domain resource.

[0013] Optionally, in any of the above aspects, the method further includes: the UE determining that the transmission of SRS conflicts with another transmission / reception in the first time domain resource; when the priority of the transmission of SRS is higher than the priority of the other transmission / reception, the UE transmits SRS in the first time domain resource.

[0014] Optionally, in any of the above aspects, the method further includes: receiving the priority of the SRS via the UE.

[0015] Optionally, in any of the above aspects, the SRS has at least one transmission parameter shared by the data transmission or high-priority data transmission associated with the SRS.

[0016] According to another aspect of this disclosure, a method is provided, comprising: a user equipment (UE) receiving control information for transmitting one or more sounding reference signals (SRS), the control information including information indicating frequency resources in a carrier for the transmission of the one or more SRS; the UE determining, based on the control information, to divide the frequency resources into multiple segments, each segment including multiple consecutive physical resource blocks (PRBs); and the UE transmitting the first SRS of the one or more SRS in a first segment of the multiple segments in a first orthogonal frequency division multiplexing (OFDM) symbol, without transmitting the first SRS in a second segment of the multiple segments, based on the control information.

[0017] Optionally, in any of the above aspects, the transmission includes: the UE transmitting SRS on multiple segments using different OFDM symbols according to control information.

[0018] Optionally, in any of the above aspects, the transmission includes: the UE transmitting a second SRS on a second segment using a second OFDM symbol based on control information.

[0019] Optionally, in any of the above aspects, the first SRS on the first segment and the second SRS on the second segment are transmitted according to the frequency hopping mode.

[0020] Optionally, in any of the above aspects, the control information includes information instructing the transmission of SRS according to the frequency hopping mode.

[0021] Alternatively, in either of the above aspects, the control information is downlink control information (DCI) or radio resource control (RRC) configuration information.

[0022] Optionally, in any of the above aspects, the control information includes information instructing the frequency resources to be divided into multiple segments for transmitting SRS.

[0023] Alternatively, in any of the above aspects, the control information includes information indicating the number of multiple segments.

[0024] Optionally, in any of the above aspects, determining to divide the frequency resources into multiple segments includes: the UE determining that the frequency resources are divided into multiple segments when the multiple segments are not continuous with each other.

[0025] Optionally, in any of the above aspects, transmitting the first SRS includes: the UE repeatedly transmitting the first SRS on the first segment of a plurality of segments in a plurality of OFDM symbols.

[0026] Optionally, in any of the above aspects, the control information includes information instructing the repeated transmission of the first SRS.

[0027] Optionally, in any of the above aspects, the method further includes: the UE receiving a physical downlink shared channel (PDSCH) on frequency resources in a carrier.

[0028] Optionally, in any of the above aspects, the control information includes information indicating an index of a first time-domain resource among the available time-domain resources for transmitting the SRS resource set; wherein the method further includes: the UE determining the available time-domain resources for transmitting the SRS resource set according to the time slot of the received control information; and the UE determining the position of the first time-domain resource among the available time-domain resources according to the index of the first time-domain resource, the first time-domain resource including a first OFDM symbol.

[0029] According to another aspect of this disclosure, a method is provided, comprising: transmitting downlink control information (DCI) for the transmission of a trigger probe reference signal (SRS) resource set to a user equipment (UE) from an access node (AN), wherein the DCI includes information indicating the position of a first time domain resource in available time domain resources for the transmission of the SRS resource set, and the available time domain resources for the transmission of the SRS resource set are based on a first timeslot of the transmission DCI; and receiving the SRS from the UE by the AN according to the position of the first time domain resource.

[0030] Optionally, in any of the above aspects, the method further includes: determining available time-domain resources for transmitting the SRS resource set based on the first time slot of the transmission DCI, wherein the determination includes: the AN determining a reference time slot for the available time-domain resources based on the location of the first time slot of the DCI and the higher-layer parameter slotoffset; and the UE determining the location of the available time-domain resources for transmitting the SRS resource set based on the reference time slot.

[0031] Alternatively, in any of the above aspects, the reference slot is the first slot for transmitting DCI when the higher-layer parameter slotoffset is not configured for the UE.

[0032] Alternatively, in any of the above aspects, the reference slot is located n slots after the first slot, where n is specified by the higher-layer parameter slotoffset configured for the UE, and n is greater than or equal to 0.

[0033] Alternatively, in any of the foregoing aspects, available time-domain resources include time-domain resources located in or after a reference time slot and configured as uplink (UL) or flexible, wherein the time-domain resources are in units of time slots, mini-time slots, or OFDM symbols.

[0034] Optionally, in any of the above aspects, DCI includes an index of the first time-domain resource in the available time-domain resources.

[0035] Optionally, in any of the above aspects, receiving SRS includes: when the transmission of SRS conflicts with another transmission / reception in the first time domain resource, the AN receives the SRS in the next time domain resource of the first time domain resource among the available time domain resources, instead of receiving the SRS in the first time domain resource.

[0036] Optionally, in any of the above aspects, receiving SRS includes: receiving SRS by the AN on a first time domain resource.

[0037] Optionally, in any of the above aspects, the SRS has at least one transmission parameter shared by data transmissions or high-priority data transmissions associated with the SRS.

[0038] According to another aspect of this disclosure, a method is provided, comprising: transmitting control information from an access node (AN) to a user equipment (UE) for the transmission of one or more sounding reference signals (SRS), the control information including information indicating frequency resources in a carrier for the transmission of the SRS; and, in response to the transmission control information, receiving, by the AN, a first SRS of one or more SRSs in a first orthogonal frequency division multiplexing (OFDM) symbol in a first segment of a plurality of segments divided by frequency resources, without receiving the first SRS in a second segment of the plurality of segments, each segment comprising a plurality of consecutive physical resource blocks (PRBs).

[0039] Optionally, in any of the above aspects, receiving includes: the AN receiving SRS from the UE on multiple segments with different OFDM symbols respectively.

[0040] Optionally, in any of the foregoing aspects, receiving includes: receiving a second SRS from the UE by the AN on the second segment in a second OFDM symbol.

[0041] Optionally, in any of the above aspects, the first SRS on the first segment and the second SRS on the second segment are received according to the frequency hopping mode.

[0042] Optionally, in any of the above aspects, the control information includes information instructing the transmission of SRS according to the frequency hopping mode.

[0043] Alternatively, in either of the above aspects, the control information is downlink control information (DCI) or radio resource control (RRC) configuration information.

[0044] Optionally, in any of the above aspects, the control information includes information instructing the frequency resources to be divided into multiple segments for transmitting SRS.

[0045] Alternatively, in any of the above aspects, the control information includes information indicating the number of multiple segments.

[0046] Alternatively, in any of the above aspects, multiple segments are not continuous with each other.

[0047] Optionally, in any of the above aspects, receiving the first SRS includes: the AN repeatedly receiving the first SRS from the UE on the first segment of a plurality of segments using a plurality of OFDM symbols.

[0048] Optionally, in any of the above aspects, the control information includes information instructing the repeated transmission of the first SRS.

[0049] Optionally, in any of the above aspects, the method further includes: transmitting a physical downlink shared channel (PDSCH) from the AN to the UE on frequency resources in the carrier.

[0050] According to another aspect of this disclosure, an apparatus is provided, comprising: a non-transitory memory including instructions; and one or more processors communicating with the memory, wherein the instructions, when executed by the one or more processors, cause the apparatus to perform the method of any of the above aspects.

[0051] According to another aspect of this disclosure, a non-transitory computer-readable medium is provided that stores computer instructions, which, when executed by one or more processors of the device, cause the device to perform the method described above.

[0052] According to another aspect of this disclosure, a system is provided, including an access node (AN) and a user equipment (UE), wherein the AN is configured to: transmit downlink control information (DCI) for triggering SRS transmission of a probe reference signal (SRS) resource set to the UE, wherein the DCI includes information indicating the position of a first time-domain resource in available time-domain resources for transmitting the SRS resource set, and the available time-domain resources for transmitting the SRS resource set are based on a first timeslot of the transmitted DCI; receive SRS from the UE according to the position of the first time-domain resource; wherein the UE is configured to: receive the DCI from the AN; determine available time-domain resources for transmitting the SRS resource set according to the first timeslot of the received DCI; determine the position of the first time-domain resource in the available time-domain resources according to the DCI; and transmit SRS to the AN according to the position of the first time-domain resource.

[0053] According to another aspect of this disclosure, a system is provided, including an access node (AN) and a user equipment (UE), wherein the AN is configured to: transmit control information to the UE for transmitting one or more sounding reference signals (SRS), the control information including information indicating frequency resources in a carrier for transmitting the one or more SRS; in response to transmitting the control information, receiving a first SRS of the one or more SRS from the UE in a first orthogonal frequency division multiplexing (OFDM) symbol on a first segment of a plurality of segments divided by frequency resources, without receiving the first SRS in OFDM symbols on a second segment of the plurality of segments, each segment including a plurality of consecutive physical resource blocks (PRBs); wherein the UE is configured to: receive the control information; determine, based on the control information, to divide the frequency resources into a plurality of segments; and transmit the first SRS of the one or more SRS in a first OFDM symbol on the first segment of the plurality of segments, without transmitting the first SRS in OFDM symbols on a second segment of the plurality of segments, based on the control information.

[0054] The advantages mentioned above include flexible triggering of SRS transmissions, dynamic configuration of SRS resources, closer association between SRS transmissions and the data transmissions to be performed, and more accurate reflection of channel interference. This can significantly reduce SRS transmission conflicts, reduce SRS overhead, reduce the impact of interference on data communication, improve the spectral efficiency (SE) of networks and terminal devices, and enhance the user experience. Attached Figure Description

[0055] To gain a more complete understanding of this disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0056] Figure 1 A diagram of an example wireless communication system is shown;

[0057] Figure 2 A diagram of an example communication system is shown, and mathematical expressions for the signals transmitted in the communication system are provided;

[0058] Figure 3 A flowchart illustrating the operations performed during interference detection according to an exemplary embodiment presented herein is shown;

[0059] Figure 4 The time-slot diagram highlights the existing SRS triggering and transmission schemes;

[0060] Figure 5 This is a time-slot diagram, highlighting SRS triggering and transmission according to the example embodiments presented herein;

[0061] Figure 6 and Figure 7 Example mappings of resource block groups (RBGs) and SRS resources and ports according to the exemplary embodiments presented herein are shown;

[0062] Figure 8 A diagram illustrating messages exchanged by a communication device performing interference detection according to an example embodiment presented herein;

[0063] Figure 9 A first example DCI according to the example embodiments presented herein is shown;

[0064] Figure 10 A second example DCI is shown according to the example embodiments presented herein;

[0065] Figure 11 A third example DCI is shown according to the example embodiments presented herein;

[0066] Figure 12 A fourth example DCI is shown according to the example embodiments presented herein;

[0067] Figure 13A flowchart illustrating an example operation performed in a UE according to an example embodiment presented herein;

[0068] Figure 14 A flowchart is shown illustrating an example operation performed in an access node according to an example embodiment presented herein;

[0069] Figure 15 A flowchart illustrating example operations performed in an access node configured with uplink SRS according to an example embodiment presented herein is shown.

[0070] Figure 16 A flowchart is shown illustrating an example operation performed in a UE transmitting uplink SRS according to an example embodiment presented herein;

[0071] Figure 17 An example of GC DCI for A-SRS transmission according to the exemplary embodiments presented herein is shown;

[0072] Figure 18 A diagram illustrating an example BIT based on A-SRS triggering with dynamic indication of partial frequency detection according to an example embodiment presented herein;

[0073] Figure 19 A diagram illustrating the partitioning of frequency resources used for SRS transmission according to an example embodiment presented herein;

[0074] Figure 20A An example single-bit operation flow is shown according to the example embodiments presented herein;

[0075] Figure 20B and Figure 20C A communication system with prominent example interference conditions according to the exemplary embodiments presented herein is illustrated;

[0076] Figure 21A and Figure 21B The figure shows a data graph of example BIT performance according to the example embodiments presented herein;

[0077] Figure 22 A diagram illustrates the information exchanged between the gNB and the UE when the gNB is configured with UL SRS detection and then performs DL transmission based on the UL SRS detection results, according to an example embodiment presented herein.

[0078] Figure 23 A diagram of an example RGB mapping with SRS resources and ports according to an example embodiment presented herein is shown;

[0079] Figure 24A , Figure 24B , Figure 24C and Figure 24DThe diagram illustrates different PRB detection modes according to the example embodiments presented herein;

[0080] Figure 25A A graph illustrating the complementary cumulative distribution function (CCDF) of PAPR in scenario 4 according to the example embodiments presented herein;

[0081] Figure 25B A diagram illustrating the CCDF of PAPR in scenario 5 according to the example embodiments presented herein;

[0082] Figure 26 A flowchart of an embodiment of a wireless communication method;

[0083] Figure 27 A flowchart illustrating another embodiment of a wireless communication method;

[0084] Figure 28 A flowchart illustrating another embodiment of a wireless communication method;

[0085] Figure 29 A flowchart illustrating another embodiment of a wireless communication method;

[0086] Figure 30 An example communication system according to an example embodiment presented herein is shown;

[0087] Figure 31A and Figure 31B Example devices are shown that can implement the methods and teachings according to this disclosure;

[0088] Figure 32 This is a block diagram of a computing system that can be used to implement the devices and methods disclosed herein. Detailed Implementation

[0089] The structure and use of the disclosed embodiments are described in detail below. However, it should be understood that this disclosure provides many applicable concepts that can be embodied in various specific contexts. The specific embodiments discussed are merely illustrative of the specific structure and use of the embodiments and do not limit the scope of this disclosure.

[0090] The Sounding Reference Signal (SRS) is a reference signal transmitted by the User Equipment (UE) in the uplink (UL) for purposes such as enabling uplink channel estimation and detecting channel interference. Based on the SRS, the network can dynamically schedule communication with the UE. The SRS plays a crucial role in wireless communication, for example in Time Division Duplex (TDD) downlink (DL) full multiple-input multiple-output (MIMO) channel state information (CSI) acquisition, TDD / Frequency Division Duplex (FDD) UL CSI acquisition, beam management, frequency selective scheduling, UL timing advance (TA) maintenance, and positioning.

[0091] The configuration of SRS transmission is typically semi-static, which limits its practicality. Embodiments of this disclosure provide a dynamic triggering and configuration mechanism for SRS transmission.

[0092] In some embodiments, a user equipment (UE) may receive downlink control information (DCI) that triggers the transmission of an SRS resource set. The DCI indicates a time-domain resource among the available time-domain resources for transmitting the SRS resource set. The UE can determine the location of the time-domain resource within the available time-domain resources based on the DCI; for example, the DCI includes an index of the time-domain resource among the available time-domain resources, and transmits the SRS according to the location of the time-domain resource. In one embodiment, when the transmission of SRS in a time-domain resource conflicts with the transmission or reception of other signals, the next available time-domain resource can be used to transmit the SRS.

[0093] In some embodiments, the UE may receive control information indicating frequency resources in a carrier for transmitting one or more SRS. The UE may determine, based on the control information, to segment the frequency resources, where each segment comprises a contiguous physical resource block (PRB), and transmit the SRS in Orthogonal Frequency Division Multiplexing (OFDM) symbols on a first segment rather than a second segment. In one embodiment, the SRS may be repeatedly transmitted on one or more segments using different OFDM symbols. In another embodiment, the SRS may be transmitted on different segments based on a frequency hopping pattern. In 5G NR, the uplink supports both OFDM and single-carrier frequency division multiplexing (SC-FDM). The symbols used in this disclosure may be OFDM symbols or SC-FDM symbols. The embodiments of this disclosure use OFDM symbols as examples only. Those skilled in the art will recognize that the embodiments are also applicable to SC-FDM symbols.

[0094] This embodiment enables flexible triggering of SRS transmissions and dynamic configuration of SRS resources. These embodiments also allow for a closer correlation between SRS transmissions and the data transmissions to be performed, and allow for a more accurate reflection of channel interference. This embodiment can significantly reduce the impact of interference on communication, reduce SRS transmission conflicts, reduce SRS overhead, improve the overall spectral efficiency (SE) of the network and individual devices, and enhance the user experience.

[0095] Figure 1 An example wireless communication system 100 is illustrated. The communication system 100 includes an access node 110 having a coverage area 111. Access node 110 serves multiple user equipments (UEs), including UE 120 and UE 122. Transmissions from access node 110 to the UEs are referred to as downlink (DL) transmissions and occur on the downlink channel (…). Figure 1 (shown as a solid arrow line in the image), and the transmission from the UE to the access node 110 is called uplink (UL) transmission, which occurs on the uplink channel ( Figure 1(Dash lines are shown in the image). Services can be provided to multiple UEs by a service provider connected to access node 110 via backhaul network 130 (e.g., the Internet). Wireless communication system 100 may include multiple distributed access nodes 110.

[0096] In a typical communication system, there are several operating modes. In cellular mode, communication with multiple UEs is through the access node 110, while in device-to-device communication modes, such as in Proximity Service (ProSe) mode, direct communication between UEs is possible. Access nodes are also commonly referred to as Node B, Evolved Node B (eNB), Next Generation (NG) Node B (gNB), Primary eNB (MeNB), Secondary eNB (SeNB), Primary gNB (MgNB), Secondary gNB (SgNB), Network Controller, Control Node, Base Station, Access Point, Transmitter Point (TP), Transceiver Point (TRP), Cell, Carrier, Macro Cell, Femtocell, Picocell, Relay, Customer Premises Equipment (CPE), etc. UEs are also commonly referred to as mobile stations, mobile devices, terminals, users, subscribers, sites, communication equipment, CPEs, relays, Integrated Access and Backhaul (IAB) relays, etc. It is important to note that when using relays (based on relays, pico, CPE, etc.), especially with multi-hop relays, the boundary between the controller and the node controlled by the controller can become blurred, and a dual-node deployment where the first node provides configuration or control information to the second node (e.g., the controller or the node controlled by the controller) is considered the controller. Similarly, the concepts of UL and DL transmissions can be extended.

[0097] A cell may include one or more bandwidth portions (BWPs) of a UL or DL ​​allocated to a UE. Each BWP may have its own BWP-specific parameters and configuration. It is important to note that not all BWPs need to be active for the UE simultaneously. A cell may correspond to one or more carriers. Typically, a cell (e.g., a primary cell (PCell) or secondary cell (SCell)) is a component carrier (e.g., a primary component carrier (PCC) or secondary CC (SCC)). For some cells, each cell may include multiple carriers in the UL; one carrier is referred to as a UL carrier with an associated DL or a non-supplementary UL (non-SUL) carrier, and the other carriers are referred to as supplementary UL (SUL) carriers without an associated DL. A cell or carrier may be configured with a time slot or subframe format consisting of DL and UL symbols, and the cell or carrier is considered to operate in Time Division Duplex (TDD) mode. Typically, for unpaired spectrum, the cell or carrier is in TDD mode, and for paired spectrum, the cell or carrier is in Frequency Division Duplex (FDD) mode. Access nodes can provide wireless access according to one or more wireless communication protocols, such as LTE, LTE-A, 5G, 5G LTE, 5G NR, 6G, High-Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For simplicity, only one access node and two UEs are shown, but it can be understood that a communication system can employ multiple access nodes capable of communicating with multiple UEs.

[0098] In standard antenna element-to-element channel estimation, the channel between two devices is estimated by having the first device transmit a known signal to the second device at a known time or frequency resource. The signal received at the second device can be represented as:

[0099]

[0100] Where y is the signal received at the second device, x is a known signal (which can be a reference signal, pilot, or pilot signal), H is the channel model or response, and n is noise (and interference in some communication channels). Since x is known to the second device, the second device can determine or estimate H based on y.

[0101] It's important to note that the concepts of antenna, antenna element, and antenna port are often used interchangeably, but in certain specific scenarios, they may refer to different but related topics. For example, a transmit (Tx) antenna port can be formed (or virtualized) by multiple antenna elements or antennas, and the receiver only sees this one Tx antenna port, rather than each of the multiple antenna elements or antennas. Virtualization, for example, can be achieved through beamforming.

[0102] Figure 2An example communication system 200 is illustrated, and mathematical expressions for the signals transmitted in the communication system are provided. Communication system 200 includes an access node 205 that communicates with a UE 210. Figure 2 As shown, access node 205 uses transmit filter v, and UE 210 uses receive filter w. Both access node 205 and UE 210 use linear precoding or combining. Assume H is the N of the MIMO system. rx x N tx A matrix, i.e., N tx One transmitting antenna and N rx There are one receiving antenna. Its dimensions are N. tx The transmit filter v of size x Ns enables the transmitter to precode or beamform the transmitted signal, where Ns is the number of layers, streams, symbols, pilots, messages, or known sequences transmitted. The receive filter w of a multi-antenna system has a size of N. rx x Ns represents the merging matrix. It should be noted that the above description refers to transmission from access node 205 to UE 210, i.e., downlink transmission. Transmission can also occur in the reverse direction (uplink transmission), for which the channel matrix becomes H. H This is the Hermitian matrix of the channel model H, where w can be considered as a transmit filter and v as a receive filter. The w used for transmission and the w used for reception can be the same or different, and the same applies to v.

[0103] The downlink (or forward) channel 215 between access node 205 and UE 210 has a channel model or response H, while the uplink (or backward, or reverse) channel 220 between UE 210 and access node 205 has a channel model or response H. H It is the Hermitian model of the channel model H. Although Figure 2 This paper describes only one access node and one UE, but it is not limited to this scenario. Multiple UEs can be served by the access node on different time-frequency resources (e.g., FDM-TDM, as in a typical cellular system) or on the same time-frequency resources (e.g., MU-MIMO, where multiple UEs are paired together, each UE is precoded individually). In paired UEs, intra-cell interference exists. Multiple access nodes can also exist in the network, some of which can cooperate to serve UE210 using joint transmission methods (e.g., coherent joint transmission, incoherent joint transmission, cooperative multipoint transmission, etc.), dynamic point handover methods, etc. Some other access nodes may not serve UE210, and their transmissions to their respective UEs may cause inter-cell interference to UE210. This paper considers a scenario with multiple access nodes and multiple UEs, where access nodes cooperate to serve UEs and multiple-user multiple-input multiple-output (MU-MIMO) is used; the example embodiment with bidirectional training is applicable to this scenario.

[0104] In version 17, as specified in the 3GPP™ Work Item Description (WID) “Further Enhancements to NR MIMO” at the 3GPP TSG RAN meeting #86 of December 9-12, 2019 (this description is incorporated herein by reference), the further enhanced MIMO (FeMIMO) SRS enhancement WID includes:

[0105] 1. SRS enhancement, for both FR1 and FR2:

[0106] - Identify and specify enhancements to non-periodic SRS triggering to facilitate more flexible triggering and / or reduce DCI overhead / usage.

[0107] - Specify SRS switching for up to 8 antennas (e.g., xTyR, x = {1, 2, 4} and y = {6, 8}).

[0108] - Evaluate and, if necessary, specify the following mechanisms to enhance SRS capacity and / or coverage: SRS time bundling, increased SRS repetition, and partial detection across frequencies.

[0109] 2. Motivations for flexible triggering include:

[0110] - The trigger information in DCI is limited (only 1, 2 or 3 bits).

[0111] - Inflexible triggering delay.

[0112] -SRS plays an important role in DL full MIMO CSI acquisition, BM, UL frequency diversity and MIMO support.

[0113] -New addition: The important role of A-SRS in TDD cooperative MIMO detection and mitigation through DL interference.

[0114] - Based on the DL (pre)scheduling results, the UE is directed to the Tx SRS so that the gNB can estimate the DL interference and then mitigate the DL interference through precoder adjustments.

[0115] - This is somewhat similar to interference detection based on DL NZP CSI-RS to achieve better MCS. It is also done after scheduling and before PDSCH, but UL SRS is used to achieve better precoding (and thus better bidirectional training (BiT or BIT)).

[0116] - It is also closely related to SRS coverage / capacity enhancement.

[0117] According to one example embodiment, precoded, uncoded, or both precoded and uncoded uplink SRS are transmitted by the UE to the access node to assist in dynamic scheduling. These uplink SRS include specific transmission parameters (e.g., specific transmission port, transmission comb, cyclic shift, transmission bandwidth (related to SRS resources),) that can be configured via higher-layer signaling (e.g., via Radio Resource Control (RRC) or Media Access Control (MAC) Control Unit (CE) signaling). In some cases, the uplink SRS may be uncoded to support uplink channel estimation and assist in network pre-scheduling. The network pre-schedules the UE during uplink channel estimation. UE pre-scheduling may involve selecting a UE from a plurality of UEs configured by the access node, wherein the selected UEs include those suitable for receiving (or transmitting) data. Therefore, the selected UEs comprise a subset of the plurality of UEs configured by the access node. The selected UE may be referred to as the pre-scheduled UE. The suitability of the UE may be determined based on factors such as channel quality, signal quality, error rate, data transmission history, and quality of service limitations.

[0118] UE pre-scheduling can occur before the actual scheduling required for data transmission (or reception) and the actual data transmission (or reception). Generally, scheduling is unpredictable. That is, during higher-level configuration, the number of UEs and which subset of UEs to pre-schedule are unknown. Therefore, after pre-scheduling, the network can determine to reconfigure the semi-static SRS parameters based on the subset of UEs selected during pre-scheduling. Thus, there is a need for apparatuses and methods that support more dynamic configuration of control signals.

[0119] Interference detection and pre-scheduling can be performed by the network after the UE transmits uplink SRS. As previously mentioned, pre-scheduling is the process by which the access node selects a subset of UEs already configured by the access node for data transmission or reception. The selected UEs can be used to transmit precoded SRSs. These precoded SRSs can be referred to as triggered SRSs. The access node can use the precoded SRSs to determine the downlink precoder (referred to above as transmit filter v). Pre-scheduling can be performed before the actual scheduling of data transmission (or reception) and can be performed during the training phase (e.g., during bidirectional training (BiT or BIT)) to determine the downlink precoder (and combiner).

[0120] BIT, also known as forward-backward training, is a computationally inefficient, general-purpose distributed training procedure used to train and update transmit precoders and receive combiners without explicitly estimating the Channel Integration Index (CSI). BIT can be adapted to transmit beamformers in TDD MIMO communication systems, which are also commonly referred to as transmit precoders, transmit filters, spatial transmit filters, analog precoders, etc., and receive combiners (also commonly referred to as receive filters, spatial receive filters, analog combiners, etc.). In BIT, neither the transmitting nor receiving devices have prior knowledge of the CSI, particularly detailed information about the channel, such as the channel matrix H or the channel covariance matrix. This channel can be between the UE and its serving access node, or between the UE and its interfering access node (which typically requires information exchange between access nodes, such as channel information or RS information about the interfering link, so that the UE or access node can estimate the interfering link). The iterative form of BIT includes forward training (e.g., in the downlink direction) and backward training (e.g., in the uplink direction), which are repeated until convergence is achieved. A single BIT consists of a single forward training step and a single backward training step. BIT is adaptable to unknown interference and can suppress interference without requiring any channel estimation or CSI feedback, thus making BIT less sensitive to the orthogonality of the training sequences. A more detailed discussion of BIT is given in U.S. Patent Application No. 15 / 983,692, filed May 18, 2018, entitled "System and Method for Communications System Training," which is incorporated herein by reference in its entirety.

[0121] Uplink probing includes estimating the uplink channel between the access node and the UE served by the access node after receiving the uplink SRS, reflecting the interference situation in neighboring cells.

[0122] Figure 3 A flowchart of operation 300 performed during interference detection is shown. Operation 300 can indicate operations performed during interference detection involving an access node and one or more UEs.

[0123] Operation 300 begins with one or more UEs transmitting an uplink SRS (block 305). The uplink SRS can be transmitted by an active UE configured by the access node and can be used for uplink channel estimation between the configured UE and the access node. In addition to uplink channel estimation, the uplink SRS can also be used by the access node to select UEs for pre-scheduling. As previously described, the pre-scheduling UE is a UE selected by the access node from its configured UEs for transmitting a triggered uplink SRS, which the access node uses to determine a downlink precoder. In one embodiment, the uplink SRS transmitted by one or more UEs in block 305 may be unprecoded. In one embodiment, the access node selects the UE for pre-scheduling using feedback transmitted by one or more UEs, instead of using the uplink SRS. The access node performs uplink channel estimation (block 307). For example, uplink channel estimation is performed using uplink SRS transmitted by one or more UEs. Alternatively, uplink channel estimation is performed using feedback transmitted by one or more UEs.

[0124] Access nodes pre-schedule UEs (Box 309). Access nodes can pre-schedule UEs based on uplink SRS or feedback received from one or more UEs. For example, an access node selects UEs associated with an uplink SRS (or feedback) received with the highest signal quality metric. Examples of signal quality metrics include SINR, SNR, RSRP, RSRQ, received signal power, etc. Access nodes can select UEs associated with uplink SRS received with a signal quality metric exceeding a specified threshold. For example, the specified threshold can be specified by technical standards, the operator of the communication system, or through cooperation between the access node and the UE. Access nodes can select a specified number of UEs associated with uplink reference signals received with a signal quality metric exceeding a specified threshold. For example, the specified number can be specified by the operator of the communication system in technical standards or through cooperation between the access node and the UE. For example, access nodes can pre-schedule UEs based on the channel quality indicator (CQI) of the uplink channel or the precoding matrix indicator (PMI) associated with the UE. The access node transmits downlink control information (DCI) for pre-scheduling UEs to trigger SRS transmissions with specific parameters and assist the UE in measuring (e.g., using) downlink ports. The downlink control information can provide the pre-scheduling UE with SRS parameters and associated downlink associations. In other words, the downlink control information configures the SRS parameters and associated downlink associations. The downlink control information can indicate to the pre-scheduling UE which downlink CSI-RS are assigned to the pre-scheduling UE to correctly measure and determine the downlink combiner and / or uplink precoder. In one embodiment, the DCI can be a group-based DCI addressed to a set of UEs (e.g., all active UEs or a subset of active UEs). In another embodiment, the DCI can be a unicast DCI addressed to the UE (e.g., 5G NR DCI). The DCI (in either case) includes modified or added fields that indicate SRS parameters. The access node can transmit CSI-RS (box 311). CSI-RS (if the access node is to transmit CSI-RS) can be transmitted in a pre-coded or un-pre-coded manner. The UE can perform downlink channel estimation (box 313). When the access node transmits CSI-RS, the UE performs downlink channel estimation based on the received CSI-RS. In one embodiment, only the UE that receives the downlink control signal (i.e., the pre-scheduled UE) performs downlink channel estimation.

[0125] The pre-scheduled UE transmits the triggered uplink SRS (block 315). The pre-scheduled UE transmits the uplink SRS according to the configuration of the downlink control signal. In one embodiment, the uplink SRS may be pre-coded or un-pre-coded (containing no information). The uplink SRS is transmitted according to the SRS configuration. For example, the pre-scheduled UE transmits its uplink SRS in the configured SRS resources, through the configured transmission port, using the configured subband, comb, and cyclic shift, and using the configured transmission bandwidth, as configured by the downlink control signal.

[0126] SRS configuration can include the configuration of SRS parameters. SRS parameter configuration, such as SRS resource sets (SRS resources within a set), SRS transmission bandwidth, SRS transmission ports, SRS transmission combs, and cyclic shifts, can be performed using higher-level configuration. An SRS resource set can include one or more SRS resources, and the SRS resource set is triggered as a whole. An SRS resource can specify one or more parameters for SRS transmission, such as port number, RE to be used for SRS transmission, sequence to be used for SRS, whether SRS is aperiodic, periodic, or semi-persistent, associated DL signals for SRS, etc. TS 38.214 v16.5.0 (2021-04) specifies the SRS parameters configured by the higher-level parameters SRS-Resource or SRS-PosResource and SRS-ResourceSet by reference. TS 38.331 v16.4.1 (2021-04) specifies the SRS-Resource and SRS-ResourceSet information units by reference. The arrangement of SRS resources or ports can be defined by the network, and the network can configure the UE with different arrangements. In addition, the network can configure different mappings (e.g., relationships, associations) between downlink ports, layers, reference signals (such as DMRS, CSI-RS) and uplink ports or layers (SRS) for the UE.

[0127] A key aspect of supporting BiT and various SRS enhancements is increasing the flexibility of non-periodic SRS (A-SRS, A SRS, AP-SRS, or AP SRS) triggering, driven by at least the following motivations in addition to BiT-related ones. That is, flexible A-SRS triggering can be designed and used outside of BiT applications. For example, a BiT-supporting design can also be used for the special case of zero-forcing (ZF) without requiring any inter-cell cooperation, such as semi-static coordination. A-SRS can be used to probe the DL channel / interference of paired UEs within a cell. Specifically, the UE transmits A-SRS on the PRB indicated by the network for PDSCH, and the network adjusts the PDSCH precoding based on these partial bandwidth A-SRS, rather than based on persistent / semi-persistent SRS (P / SP SRS, or P / SP-SRS), which is periodically transmitted by the UE to cover the entire bandwidth and has a longer period in typical ZF schemes. Traditional ZF is generally based on P / SP SRS. The SRS must cover the bandwidth (with or without frequency hopping), and all active UEs must be probed. Therefore, the P / SP SRS period cannot be small for all UEs; otherwise, SRS will lead to huge overhead. In fact, when inter-cell interference (or the covariance matrix of inter-cell interference) is ignored, the above scheme simplifies to single-cell massive MIMO, i.e., ZF, but the detection used for ZF is based on A-SRS, whose frequency domain resources, ports, and beamforming are tied to PDSCH. Only UEs scheduled using PDSCH in the next few transmission time intervals (TTIs) will transmit A-SRS. The A-SRS PRB, ports, and beamforming are the same as the expected PDSCH. A-SRS provides the network with the ZF precoder to adjust the PDSCH. Therefore, the aging of A-SRS will not exceed a few TTIs, which ensures high accuracy of precoding / beamforming, thereby achieving high spectral efficiency (SE). With these A-SRS, the P / SP SRS period can be increased, thereby reducing the overall SRS overhead. Therefore, ZF based on A-SRS features downlink interference detection without any inter-cell coordination, thus outperforming ZF based on P / SP-SRS in terms of beamforming accuracy, interference suppression, and overhead reduction. The key standard component required to support this enhancement remains flexible A-SRS triggering, similar to BiT.

[0128] The trigger information in the current DCI is limited (only 1, 2, or 3 bits):

[0129] SRS transmission is associated with many parameters, such as comb, cyclic shift, transmission bandwidth expressed in terms of the number of PRBs on the serving cell's UL or SUL, and antenna ports. In existing standards, A-SRS can be triggered via the SRS request field in the DCI, which can include 1, 2, or 3 bits. These bits can indicate: 1) certain SRS resource sets for the current serving cell, or 2) certain SRS resource sets on the serving cell, or 3) one of the UL and SUL. However, many other SRS transmission parameters cannot be indicated in the DCI and can only be specified in the RRC configuration signaling. For example, due to DCI bit width limitations, the network may have to configure several SRS resource sets together, or several serving cells together, meaning these sets must be triggered together, which is highly undesirable. Generally, limited triggering information leads to a lack of flexibility in many applications, as described below; therefore, the motivation is to improve the flexibility of A-SRS triggering.

[0130] Trigger offset (delay) lacks flexibility:

[0131] In the existing standard, the A-SRS trigger offset is configured through the slotOffset field of the RRC for 1 to 32 slots. If this field is not configured, 0 slot offsets are applied. Figure 4 The diagram for time slot 400 highlights the existing SRS triggering and transmission scheme. In this example, the A-SRS trigger offset configured for the UE via RRC signaling is 4. The gNB can send a DCI in time slot 402 to trigger SRS transmission by the UE. Based on the A-SRS trigger offset, the UE is used to transmit SRS in time slot 404, four time slots after time slot 402.

[0132] In some cases, this can be limiting. For example, when using Group Common (GC) DCI format 2_3 to trigger SRS for a group of UEs on one or more of their serving cells, all SRS transmissions will occur after a pre-configured offset relative to the same DCI trigger slot. For example, all SRS transmissions will be performed four slots after the DCI trigger slot. This can impose significant limitations on the network's decision of which slots to send GC DCI. As another example, SRS triggering by DL DCI may conflict with acknowledged / unacknowledged (A / N) signals associated with DLDCI, and SRS triggering by UL DCI may conflict with PUSCH signals associated with UL DCI, especially in TDD when UL slots are less frequent. Generally, the primary purpose of A-SRS triggering is to provide flexibility in SRS timing, but the predetermined timeline in the trigger offset and the mostly fixed slot structure do not achieve this well. Enhancements are needed. For another example, if an SRS transmission in slot 404 conflicts with the transmission or reception of another signal, the UE may be unable to transmit SRS even if it is triggered to do so. Furthermore, existing schemes limit the use of other available time slots for SRS transmission. For example, since the UE can only transmit SRS in time slots configured based on a fixed A-SRS trigger offset, even if another time slot exists that can be used for SRS transmission, such as time slot 408 (uplink time slot), the UE cannot use time slot 408 to transmit SRS. Additionally, existing schemes limit the selection of available time slots for SRS triggering. For example, time slot 406 (downlink time slot) can be used for downlink transmission, but time slot 406 cannot be used to trigger SRS transmission because, according to the fixed A-SRS trigger offset, the four time slots following time slot 406 (i.e., time slot 410) are not uplink time slots and cannot be used for SRS transmission.

[0133] The various important roles of A-SRS:

[0134] A-SRS plays a crucial role in TDD DL full MIMO CSI acquisition, TDD / FDD UL CSI acquisition, FR2 beam management, frequency-selective scheduling, UL timing advance (TA) maintenance, and positioning. It is also critical to FDD DL performance. However, the lack of flexibility in the aforementioned SRS triggering limits its practicality. For example, if an SRS is dropped due to a conflict caused by the inflexible trigger offset, CSI acquisition and frequency-selective scheduling may be affected. Note that CSI acquisition and frequency-selective scheduling can be highly dynamic, therefore P / SP-SRS is not suitable. In LTE Rel-14 SRS carrier handover, autonomous A-SRS retransmission was introduced, allowing dropped A-SRS triggered by DL DCI (i.e., conflicting with A / N) to be autonomously retransmitted at the next configured SRS transmission time, but this feature is not yet supported in 5G NR. To ensure that P / SP-SRS and A-SRS complement each other well, P / SP-SRS can be configured with long periods (avoiding excessive overhead and complexity), while the network relies on A-SRS for rapid response to traffic load and CSI (especially dynamic interference). Therefore, given the various important roles played by A-SRS, flexible A-SRS triggering is beneficial in many situations and should be supported.

[0135] Closely related to SRS capacity / coverage enhancement:

[0136] SRS coverage / capacity enhancement may include, but is not limited to: 1) enhancing SRS capacity on a portion of the bandwidth via SRS, where the bandwidth can be dynamically indicated via DCI; 2) enhancing SRS capacity on unused PRBs / symbols in the PUSCH / PDSCH area via SRS, where SRS time-frequency resources can be dynamically indicated via DCI based on unused resources in the TTI; 3) enhancing SRS capacity by multiplexing SRS with other signals (e.g., A / N) (on the same symbol) to accommodate flexible SRS multiplexing, thereby maximizing SRS capacity; 4) enhancing SRS coverage via narrowband transmission based on frequency selectivity (rather than pre-configured PRBs), etc. Some enhancements also apply to P / SP-SRS; however, especially for capacity enhancement, SRS needs to be sufficiently flexible. For example, when the network recognizes that A-SRS has an opportunity to fill gaps in time-frequency resources (e.g., unused symbols in a time slot, some unused PRBs, etc.), it can trigger the UE to perform A-SRS. Therefore, flexible triggering of A-SRS is also useful for SRS capacity / coverage enhancement.

[0137] To effectively convey information about dynamic interference conditions to the network, the gNB can instruct the UE on how to transmit SRS, including time / frequency resource allocation and port selection for the SRS corresponding to the expected PDSCH. This means that compared to traditional SRS transmission, the network needs to dynamically adjust more SRS transmission parameters (such as PRB allocation and port selection). An example for SRS transmission is provided, whose parameters are tied to DL transmission, including PRB allocation, time-domain resource allocation, and port allocation.

[0138] One embodiment is used for A-SRS PRB / port allocation indication. The SRS PRB / port allocation can be the same as the expected PDSCH and can be dynamically indicated.

[0139] One embodiment is for A-SRS beamforming indication. SRS beamforming can be based on DL channel measurement resources (CMR), and to better reflect potential DL interference, it is preferable to be based on DL CMR and IMR, one or both of which can be dynamically indicated. One embodiment is for A-SRS trigger offset. To utilize A-SRS to estimate interference and mitigate it through precoding adjustments, the gNB does not need to detect the SRS sequence for each UE. The accumulated received SRS power on each gNB receive antenna port should be sufficient. Therefore, A-SRS can be transmitted on overlapping resources to reduce overhead. However, A-SRS triggers can be sent to different UEs at different times. To enable A-SRS overlap, the A-SRS trigger offset can be dynamically indicated to different UEs. The trigger offset can be similar to the k0 and start and length indicator (SLIV) of the PDSCH (i.e., Time Domain Resource Allocation (TDRA)). To further reduce overhead, k0 and the start and length indicator (SLIV) may not refer to an absolute slot / symbol offset, but rather a slot / symbol offset based on the configured SRS slot / symbol. TDRA overhead can be further reduced, for example, by not indicating time slots but only indicating symbols. TDRA in SRS can be omitted in DCI and is based on RRC / MAC.

[0140] The time-domain resources that A-SRS can use are explained below. Based on the time-domain resources that A-SRS can use, the design and indication of the trigger offset are discussed.

[0141] Time-domain resources that can be used for A-SRS with flexible triggering can be defined to avoid potential ambiguity. For example, one suggestion is to delay A-SRS transmission to the next "available" time slot, but this could lead to errors if the network and UE interpret "available" time slots differently. Possible A-SRS time-domain resources can include time-domain resources that do not exclude SRS transmission, such as all time slots and Orthogonal Frequency Division Multiplexing (OFDM) symbols not configured as DL by RRC. In other words, possible A-SRS time-domain resources can be a set of potential A-SRS transmission opportunities in the time domain. For example, according to TDD-UL-DL-ConfigCommon or TDD-UL-DL-ConfigDedicated, all time slots and OFDM symbols used for UL or flexible can be considered possible A-SRS time-domain resources. As another example, all time slots and OFDM symbols, regardless of whether they are configured as DL, UL, or flexible, can be considered possible A-SRS time-domain resources. The former approach has advantages, such as reduced overhead for trigger offset indication (since the indication may need to reference a subset of slots / symbols, rather than all slots / symbols), but its main disadvantage is that determining whether a slot / symbol is DL, UL, or flexible can be complex and may change over time, potentially leading to confusion. On the other hand, the latter approach may require more bits to cover the same duration, or the same bits but covering a shorter duration, but it significantly simplifies the design. The latter approach does not introduce ambiguity if the transmission direction of the slot / symbol is covered by DCI. The latter approach provides the same A-SRS time domain resources for both FDD and TDD, which is advantageous when both FDD and TDD are aggregated. The latter approach also allows some unused DL slots / symbols to potentially be used for A-SRS with appropriate UL / DL switching gaps, further improving the triggering flexibility of A-SRS. Therefore, in one embodiment, all slots / symbols can be designated as possible A-SRS time domain resources. For either approach, if the parameters change between received DCI and A-SRS transmissions, the A-SRS will be discarded.

[0142] As used herein, possible A-SRS time-domain resources may also be referred to as available time-domain resources of SRS for transmitting A-SRS, or available time-domain resources of SRS for transmitting A-SRS, or available time-domain resources for A-SRS. As used herein, SRS of A-SRS refers to SRS in a set of aperiodic SRS resources. In the art, A-SRS generally refers to a set of aperiodic SRS resources. Other terms may be used without departing from the spirit and principles of this disclosure, such as effective time-domain resources for transmitting SRS, or acceptable time-domain resources for transmitting SRS. It should also be noted that when referring to SRS, "transmitting SRS" and "transmitting SRS resources" may also be used.

[0143] The granularity of resource allocation can also be defined when explicitly or implicitly indicating the allocation of time-domain resources to a flexible A-SRS. For example, resource indication in the DCI can be slot-based, in which case the OFDM symbols to be used by the A-SRS are based on the RRC configuration. That is, the DCI can flexibly indicate in which slot the A-SRS will transmit (e.g., two slots later than the current DCI slot) but does not provide symbol information (e.g., it is provided in the RRC to reduce DCI overhead). As another example, the DCI indication can be based on mini-slots (non-slots), for example, on the fifth mini-slot of the second slot after the current DCI slot, or on the tenth mini-slot after the current DCI mini-slot. This can be particularly useful for Ultra-Reliable Low-Latency Communication (URLC) that already operates using mini-slots. Yet another example, the DCI indication can be based on OFDM symbols, for example, on the tenth symbol of the second slot after the current DCI slot, or on the twentyth symbol after the current DCI symbol. Generally, finer granularity requires higher indication overhead, but also provides greater flexibility.

[0144] In some embodiments, a reference time (start point) for the SRS trigger offset can be specified. The reference time is the point at which the calculation of the SRS trigger offset begins. One approach is to define the start point based on the current DCI slot / mini-slot / symbol (where the DCI is transmitted to trigger the SRS transmission). It is important to note that the reference time granularity should generally be consistent with the A-SRS time domain resource allocation granularity. Other approaches can also be considered, such as relative to the current DCI slot plus a slot offset (if already configured by RRC), or relative to the next flexible / UL slot / symbol. If the granularity is slot, the current DCI slot is considered the reference time for the A-SRS trigger offset (slot 0). In this case, the reference time can also be referred to as the reference slot. If the granularity is mini-slot, the mini-slot immediately following the current DCI mini-slot is considered the reference time for the A-SRS trigger offset (mini-slot 0). If the granularity is symbol, the symbol immediately following the last symbol of the current DCI is considered the reference time for the A-SRS trigger offset (symbol 0). If A-SRS is used for CSI acquisition of a specific UL / DL data transmission, the A-SRS time can be relative to the associated data transmission (for URLLC, etc.) (before this). Typically, this design can be easily extended to cases where the trigger offset is relative to a reference timing, and the reference timing can be specified in the standard, RRC configuration, MAC signaling, or DCI field (e.g., indicating time slot / symbol).

[0145] Therefore, the following designs and any combination thereof can also be used for A-SRS:

[0146] - Flexible A-SRS time-domain resources

[0147] • Option A1: Not configured for all slots / OFDM symbols for DL ​​in TDD-UL-DL-ConfigCommon or TDD-UL-DL-ConfigDedicated

[0148] • Option A2: On all time slots / OFDM symbols

[0149] - Flexible A-SRS time-domain resource allocation. Allocation granularity can be:

[0150] • Option B1: Based on time slot

[0151] • Option B2: Based on time slots, is a mini-time slot.

[0152] • Option B3: Based on time slots and OFDM symbols

[0153] - Flexible reference time for SRS trigger offset.

[0154] • Option C1: Reference time is based on the current DCI slot / mini-slot. When the granularity is slot, the current DCI slot can be considered as the reference time for A-SRS time domain resources and trigger offset (slot 0). When the granularity is mini-slot, the mini-slot immediately following the current DCI mini-slot can be considered as the reference time for the A-SRS trigger offset reference point (mini-slot 0).

[0155] • Option C2: If the reference point is symbol-based, then the symbol immediately following the last symbol in the current DCI can be considered the reference point.

[0156] • If A-SRS is used for CSI acquisition of a specific UL / DL data transmission, the A-SRS time can be relative to the associated data transmission (e.g., prior to it). If A-SRS is combined with data, the time slot preceding the data with the UL symbol available for SRS can be the reference time. In some cases, these may require a negative A-SRS trigger offset.

[0157] • Option C3: Reference point based on the next UL / flexible slot / symbol.

[0158] When merging different options, some degree of consistency should generally be maintained. For example, if symbol-based option A2 is considered, then symbol-based option B3 should be used, and symbol-based option C3 should also be used. Similarly, they might all be based on mini-slots, slots, etc.

[0159] Based on the above explanation, we can proceed with the design of the A-SRS trigger offset indicator. We provide the following example suggestions for indicating the A-SRS trigger offset. The following embodiments are described using a time-slot-based time resource granularity. Other granularities can also be readily used by those skilled in the art.

[0160] Recommendation 1: Delay the SRS transmission to an available time slot after the trigger offset defined in the current specification, based on the parameter slotoffset (see TS 38.214 v16.5.0 (2021-04), TS 38.331v16.4.1 (2021-04)), including the possibility of redefining the trigger offset.

[0161] There are at least several instances where delaying SRS transmissions to the next transmission opportunity (e.g., the next available time-domain resource for SRS transmission) would be useful. In existing designs, when SRS is triggered for a group of UEs on one or more serving cells using group-common (GC) DCI format 2_3, all SRS transmissions occur after a pre-configured offset relative to the same DCI trigger slot. This can impose significant limitations on the network's decision regarding the slot for transmitting GC DCIs. For example, SRS triggering for DL ​​DCIs may conflict with the A / N associated with the DL DCI, and SRS triggering for UL DCIs may conflict with the PUSCH associated with the UL DCI, especially in TDD when UL slots are less frequent. In LTERel-14 SRS carrier handover, autonomous A-SRS retransmission is introduced, allowing discarded A-SRS triggered by DL DCIs (i.e., those conflicting with A / Ns) to be autonomously retransmitted at the next configured SRS transmission opportunity. Designs along this line can provide more opportunities for discarded A-SRSs to be transmitted later. With the A-SRS time-domain resources and granularity clarified, an A-SRS conflicting with another transmission can autonomously be delayed to the nth transmission opportunity, e.g., the nth time slot / mini-slot / symbol within the A-SRS time-domain resources, where n>0. If the resources on the nth transmission opportunity are not occupied by other transmissions of the same or higher priority, the A-SRS can be transmitted there. However, if the resources are occupied by other transmissions of higher priority, the A-SRS should not be transmitted there (potentially further delayed or dropped). Rules can be specified for dropping A-SRS, such as the maximum duration in milliseconds or time slots, the maximum number of delay operations (i.e., trials) that must precede a specific time slot (e.g., before the next time slot, which is a time slot delay for low-latency purposes), and so on.

[0162] Closely related to this issue is the prioritization of flexible A-SRS. At least in some cases, A-SRS can be processed with higher priority and should not be discarded in the first place. Higher priority can be explicitly assigned by the network with priority flags, or implicitly assigned when A-SRS is associated with URLLC transport or specific data transmission (e.g., A-SRS is used for interference detection of specific data transmission, rather than for general CSI acquisition purposes).

[0163] Several options can be considered regarding the redefinition of the trigger offset, which may also depend on how the A-SRS time-domain resource is specified. The trigger offset can be indicated as a slot offset and symbol position, similar to the k0 and SLIV design of PDSCH or the k2 and SLIV design of PUSCH. To further reduce overhead, k0, k2, and SLIV may not refer to absolute slot / symbol offsets, but rather to slot / symbol offsets within the A-SRS time-domain resource. If the indicated A-SRS symbol length is greater than the A-SRS symbol length configured by RRC, the A-SRS can be repeated, skipped, or split in the time domain to fill the indicated symbol. More details on splitting are provided below. If the indicated symbol length spans into the next slot, the indicated A-SRS symbol can also cross the slot boundary and enter the next slot, similar to the existing PUSCH design. If parameters change across slot boundaries, the A-SRS on the next slot may be canceled. Typically, the A-SRS trigger offset can be indicated by a reused / enhanced UL / DL TDRA field design.

[0164] Recommendation 2: Explicitly or implicitly indicate the trigger offset in DCI.

[0165] To explicitly indicate the trigger offset, a trigger offset field can be added to the A-SRS trigger DCI, or more generally, the UL / DL TDRA field can be reused or enhanced for A-SRS.

[0166] Implicit trigger offset can be the next SRS transmission opportunity within A-SRS time domain resources, such as available time resources like time slots for transmitting SRS. In other words, the UE can autonomously search for the next block of A-SRS time domain resources available for transmitting all configured or indicated A-SRS symbols. This design can be viewed as autonomous delaying combined with an explicit trigger offset approach. For example, if the SRS TDRA field is missing, or the symbol indicated by the SRS TDRA is occupied, the UE will autonomously search for the next available opportunity to transmit SRS. This operating mode can be enabled / disabled via flags in the RRC (similar to the design of the LTE Rel-14 soundingRS-FlexibleTiming configuration) or the DCI. The UE can start searching from the time slot carrying the DCI, but if the RRC is configured and / or the DCI indicates a time slot offset value, the UE can start searching from the time slot with the configured / indicated offset. In one embodiment, if the reference time slot (based on the time slot carrying the DCI, optionally also the time slot offset configured by the RRC; other embodiments are described below) is time slot n, and the DCI indicates a time slot offset t, then the UE starts searching from time slot n+t. If time slot n+t is an available time slot for the indicated A-SRS (other embodiments are described below), then the UE transmits the A-SRS on that time slot. However, if time slot n+t is not an available time slot for the A-SRS, and if an autonomous delay has been configured / activated in case of a collision preventing the A-SRS from being transmitted in time slot n+t, the UE will start searching from time slot n+t for the next available time slot and transmit on the next available time slot. The search can be extended to a maximum of k time slots, i.e., up to time slot n+t+k. If the UE cannot find an available time slot, it discards the A-SRS. Note that if a symbol in the time slot that the SRS should occupy is occupied by another higher priority transmission / reception, a collision will occur, and therefore the SRS cannot be transmitted.

[0167] An embodiment is provided for assigning higher priority to A-SRS with newly introduced flexibility. A-SRS with at least one parameter newly introduced in the SRS request field of this application to support BiT and other enhanced A-SRS can be assigned higher priority such that other transmissions are dropped when it conflicts with it.

[0168] In some embodiments, a reference time slot design and an available time slot design are provided. The reference time slot is the time slot at which the UE / gNB begins counting with respect to a time slot offset value. A given set of aperiodic SRS resources is transmitted in the (t+1)th available time slot counted from the reference time slot, where t is indicated by DCI or RRC, and candidate values ​​for t include at least 0.

[0169] There are two options for the reference time slot:

[0170] • Option 1: The reference slot is the slot that triggers DCI.

[0171] • Option 2: The reference slot is the slot indicated by the legacy trigger offset.

[0172] Option 1 and Option 2 each have their own advantages and disadvantages. Since the A-SRS resource set is only transmitted after the reference slot, for example, if the configured old RRC slot offset is 4, Option 2 can only trigger A-SRS after 4 slots. Therefore, if the network wants to trigger A-SRS after 2 slots (e.g., the UL slot appears after 2 slots), only Option 1 can meet the requirement. In this sense, Option 1 is more flexible than Option 2. On the other hand, for non-zero slot offset values ​​configured in the RRC, Option 2 allows the UE more time to prepare for A-SRS transmission and allows the network to trigger A-SRS at a later time in the future with the same DCI overhead as Option 1. Comparing the advantages and disadvantages, Option 1 is more suitable because the enhancements to SRS in Rel-17 are designed to improve triggering flexibility.

[0173] The existing minimum trigger offset and UE capabilities for the minimum offset must be considered. According to existing standards, the minimum time interval between the last symbol of the PDCCH triggering aperiodic SRS transmission and the first symbol of the SRS resource is N² (or N²+14) symbols plus an additional duration T. switch Where N2, in units of symbols, is determined based on the UE's processing capacity; if there is an uplink handover gap, then T... switch This indicates the uplink handover interval. These requirements, defined in existing standards, can be considered when specifying enhancements, or they can be considered by the gNB through gNB implementation.

[0174] Regarding the phrase "in the (t+1)th available time slot," this can be interpreted as counting "the first available time slot," "the second available time slot," and so on, up to "the (t+1)th available time slot." In other words, only time slot resources potentially available for SRS are counted, including UL time slots and flexible time slots. Alternatively, it can be interpreted as counting "the first time slot," "the second time slot," and so on, up to "the (t+1)th time slot," and if "the (t+1)th time slot" is available, then the A-SRS resource set is transmitted. Therefore, a given aperiodic SRS resource set is transmitted in the (t+1)th time slot, and if it is an available time slot, counting begins from the reference time slot.

[0175] Regarding the definition of "available time slots," it is also useful to consider having consecutive time slots with consecutive symbols that can be used for SRS transmission, rather than restricting symbols to a single time slot. If this is supported, it is more likely to accommodate SRS transmissions without collisions. Therefore, in one embodiment, the following definition of "available time slots" can be adopted:

[0176] Based solely on RRC configuration, an "available time slot" is a time slot that satisfies the following: in one or consecutive time slots of all SRS resources in the resource set, there is an available consecutive UL and / or flexible symbol at the configured / indicated time domain location, and it satisfies the minimum timing requirements between triggering the PDCCH and all SRS resources in the resource set.

[0177] The RRC configuration configures a different number of slot offset values. For location-related SRSs, the resource set is configured with multiple slot offset values ​​via RRC; that is, the slot-level offset is defined by the higher-level parameter `slotOffset` for each SRS resource in the resource set. However, for all other SRSs, the resource set is configured with only one slot offset value via RRC. The above description of available slots can be further extended to: given a given aperiodic SRS resource within a given aperiodic SRS resource set, transmitted in the (t+1)th available slot counted from the reference slot, where t is indicated by DCI or RRC, candidate values ​​of t include at least 0, and based solely on the RRC configuration, an "available slot" is a slot that satisfies the following: in one or consecutive slots of all SRS resources in the resource set, the configured / indicated time-domain location has available consecutive ULs and / or flexible symbols, and it satisfies the minimum timing requirement between triggering the PDCCH and all SRS resources in the resource set. Some other embodiments are provided here. If the SRS resource set is associated with different slot offsets for different resources, multiple available slots can be used for the SRS resource set. In one embodiment, the relative timing relationship between resources configured by slot offset is maintained within available slots. For example, if the slot offset makes resource 2 3 slots later than resource 1, then the available slots of a set of n resources should satisfy the following: in all n single or consecutive slot sets of all SRS resources in the resource set, there are available consecutive ULs and / or flexible symbols at the configured / indicated time domain locations, and the minimum timing requirement between triggering the PDCCH and all SRS resources in the resource set is met, and the n resources are located on slots (counting only the first slot in each set), with the relative slot offset being the same as the configured slot offset. This embodiment can be quite complex, and if one resource cannot fit, the entire set must be dropped or delayed. In another embodiment, each resource in the set is processed independently for transmission on available slots, and there are no restrictions on their relative timing. If a resource cannot be accommodated in slot n+t associated with it, this resource may be dropped or delayed according to the configuration, but other resources are unaffected.

[0178] Figure 5The diagram for slot 500 according to an embodiment of the present invention highlights SRS triggering and transmission. The gNB can transmit a DCI in slot 502 to trigger the transmission of an A-SRS resource set by the UE. If no A-SRS trigger offset is configured for the UE, the reference slot (slot 0) for determining the available time-domain resources for SRS transmission can be slot 502 for transmitting the DCI. If the minimum timing requirement between the triggering DCI in slot 502 and all SRS resources is 0 to 2 slots (i.e., SRS cannot be transmitted 0 to 2 slots after the DCI), the available time-domain resources (i.e., available slots in this example) for SRS transmission after 0 to 2 slots can include slots 504, 506, 508, and 510. Each of these slots can be used by the UE to transmit SRS. Slots 504, 506, 508, and 510 can be labeled / indexed as available slots 1-4. The DCI can indicate which of the available slots 1-4 the UE can use for SRS transmission. For example, the DCI can indicate the index / number of the available time slot for the UE to transmit SRS, such as slot number 2. When triggered by the DCI, the UE can determine the location of the indicated time slot (i.e., time slot 506) based on the index / number and available time slots, and transmit the SRS in the determined time slot 506. In one embodiment, if time slot 506 is occupied by another transmission / reception, the UE can look for the next available time domain resource, i.e., time slot 508 (time slot number 3), and transmit the SRS in time slot 508. If the transmission of the SRS has a higher priority than the other transmission / reception, the UE can transmit the SRS in time slot 506 regardless of the other transmission / reception.

[0179] When an A-SRS trigger offset (e.g., 4) is configured for the UE, the UE can determine a reference time slot based on the A-SRS trigger offset and the time slot for transmitting the DCI. In this case, the reference time slot would be time slot 506, and the available time domain resources for SRS transmission could include time slots 508, 510, 512, and 514. Similarly, these four time slots can be numbered 1-4. The DCI can indicate the index / number of the time slot among the available time slots the UE uses to transmit SRS, for example, number 2. When triggered by the DCI, the UE can determine the location of the indicated time slot (i.e., time slot 510) based on the indicated index / number and the available time slots, and transmit SRS in the determined time slot 510. Note that alternatively, offsets numbered 1-4 can be mapped to 0-3. This example only shows slots D and U; typically, some slots may be configured with downlink OFDM symbols and uplink OFDM / SC-FDM symbols at the beginning of the slot, and each of these slots can still be a available time domain resource for A-SRS if A-SRS can be transmitted on that slot.

[0180] In one embodiment, upon receiving an uplink SRS, the access node pre-schedules the UE and instructs the pre-scheduled UE via signaling that the following are allocated to it: which portion of the SRS transmission bandwidth, which SRS resources or ports from different SRS resource or port arrangements, the transport comb, the cyclic shift, and which of the downlink CSI-RS ports (and / or DMRS). In addition to the listed parameters, the instructions transmitted to the pre-scheduled UE may also include associations (e.g., mappings, relationships) between uplink ports, downlink ports, or bandwidths. Downlink ports may consist of DMRS and / or CSI-RS ports. In one embodiment, the network uses group DCI messages to dynamically configure SRS parameters. In another embodiment, unicast DCI messages are used to dynamically configure SRS parameters. SRS transmitted by the pre-scheduled UE may be referred to as triggered SRS to distinguish them from uplink SRS transmitted by the UE for uplink channel estimation, e.g., in... Figure 3 In box 305, an uplink reference signal (e.g., SRS) is used to transmit the interference situation in neighboring cells and a description of the interference suppression receiver capability of the serving access node for the UE. Subsequently, the access node determines the downlink precoder (e.g., based on the received precoded SRS (i.e., the triggered SRS)) and uses the downlink precoder to transmit downlink data.

[0181] More details regarding the indication of SRS transmission parameters will be provided below.

[0182] In relation to indicating SRS resources or ports, the network indicates to the UE which SRS resources or ports have been allocated to the UE. In other words, the UE needs to know which resource in the SRS resource pool or SRS configuration resource subset is being transmitted on the uplink.

[0183] In one embodiment, the network configures different resource or port arrangements for the UE. For example, different resource or port arrangements can vary due to cyclic shifts, transmission combs, the number of symbols (e.g., Orthogonal Frequency Division Multiplexing (OFDM) symbols), etc. Different arrangements represent different mechanisms by which the network can package UE SRS resources or ports. In one embodiment, different resource or port arrangements are predefined. Indicating a predefined resource or port arrangement may require less overhead than indicating different values ​​for cyclic shifts, transmission combs, the number of symbols (e.g., OFDM symbols), etc. For example, if there are eight predefined arrangements, indicating any one of these eight can be done by indicating a 3-bit index, while indicating different values ​​may require far more than 3 bits. Predefined arrangements can be defined in the higher layers of the 3GPP standard and / or configuration. The network can shrink (further select and indicate) the size of a specific configuration after pre-scheduling (or scheduling) and can use DCI to indicate the shrunken arrangement to the UE.

[0184] As an illustrative example of SRS resource or port signaling, consider a communication system with eight Type 1 demodulation reference signaling (DMRS) ports. In an embodiment, twelve DMRS ports may be used as an illustrative example. Eight uplink SRS resources (e.g., ports) are provided for all UEs operating within a single cell, and the eight UEs are pre-scheduled. The UEs need to know which of the eight uplink SRS resources to transmit on. Therefore, it is necessary to effectively instruct the UEs to attempt to inform them which (or which) uplink SRS resources to use, minimizing the impact on the overall communication system performance. Informing the UEs which uplink SRS resources to use may involve indicating which comb, symbol, cyclic shift, number of OFDM symbols, etc., to use. As previously mentioned, in one embodiment, the UEs may be configured with different arrangements of these SRS resources or ports. For example, these arrangements may be specified by the operator of the communication system in the technical standards or determined through cooperation between communication devices. Example arrangements include:

[0185] -1 physical resource with 8 ports for 8 UEs, cyclic shift of 8 (for orthogonality between ports), and comb of 2;

[0186] -1 physical resource with 8 ports for 8 UEs, 8-way shift and 4 comb;

[0187] - 8 physical resources, with 1 port, for each of the 8 UEs;

[0188] - 2 physical resources, each with 4 ports, using cyclic shift 4.

[0189] In the first example embodiment, there is one physical resource with eight ports for eight UEs serving within the cell. The resource is cyclically shifted by 8 (to ensure orthogonality of SRS transmissions), combed by 2, and repeats on a specified number of symbols (e.g., the specified number of symbols can be specified by the operator of the communication system in the technical standard, or determined through cooperation between communication devices). A 3-bit indicator is sufficient to indicate to the UE which of the eight resources to use.

[0190] In the second example embodiment, there is one physical resource with eight ports for eight UEs operating within the cell, with a cyclic shift of 8 and a comb of 4. A 3-bit indicator is sufficient to indicate to the UE which of the eight resources to use.

[0191] In the third example embodiment, for each UE operating within the cell, there are 8 physical resources, each with 1 port, and OFDM symbols are multiplexed. A 3-bit indicator is sufficient to indicate to the UE which of the 8 resources to use.

[0192] In the fourth example embodiment, for each UE operating within the cell, there are 2 physical resources, each with 4 ports, and a cyclic shift of 4. To indicate to the UE which of the 8 resources to use, if some UEs are assigned multiple ports, for example, a UE might be assigned 2 ports, a 4-bit indication is sufficient.

[0193] These different resource or port arrangements can be predefined, and the network can configure the UE with different arrangements. The network can use the DCI to indicate one or more of these arrangements for a subset of (pre-scheduled, scheduled, active) UEs.

[0194] The example given above is just an example of resource configuration; the actual configuration may not be limited to the above. In this case, the network can use a certain number of bits (e.g., 3 to 4 bits) in the DCI to indicate to the UE which of the following arrangements of resources or ports it has been allocated (implicitly indicating the transport layer, comb, and cyclic shift).

[0195] In one embodiment, the network can define a complete set of SRS resources / ports and use indicators to indicate subsets. This design is similar to DMRS port indication in 5G NR. In another embodiment, the network can define subsets of SRS resources / ports and use indicators to indicate subsets from a configured subset. In any of these embodiments, a table can be used to summarize all possible resource sets / subsets, where ports (ranks) can be bound to cyclic shifts, combs, OFDM symbols, and offsets.

[0196] The network can define a DCI bit indicator, which can have a one-to-one mapping to port indicators for SRS, and the SRS port indicators can be bound to cyclic shift, comb, offset, or OFDM symbols. The value indicated in the DCI will be mapped to a port that can be used for SRS transmission. In one embodiment, one port can be used, such as port 0. In another embodiment, multiple ports can be used, for example, two ports can be used for SRS transmission. This field can be referred to as the number of antenna ports and layers used for SRS, and it can be indicated using a fixed number of bits in the DCI.

[0197] In another embodiment, the access node may transmit configuration information for multiple SRS resources to the user equipment (UE). The configuration information includes multiple SRS resource sets for the UE, each SRS resource set comprising one or more SRS resources. The access node then transmits an indication to the UE of one of the multiple SRS resource sets.

[0198] The antenna ports to be used for SRS transmission should be determined according to the order of SRS ports given by a predefined configuration, which can be represented by a table. The number of bits indicated in the DCI defined by the group indicates the port of transmission bound to physical resources (such as cyclic shift, comb, and OFDM symbols).

[0199] When using group DCI to transmit SRS configuration, it is possible to indicate the tier or port of the UE within the predefined SRS port resources. As an example for each cell (e.g., sector, transmit point, etc.), a predefined number of SRS port resources are allocated, such as 8 or 12 ports. In the group DCI, the network indicates the tier or port of the UE within the predefined SRS port resources. For example, the network configures SRS resources for all active UEs in the cell, and the SRS resources have the same 8 ports. The group DCI indicates which of the 8 ports is assigned to the UE. The predefined SRS port resources can be specified in the technical specifications or transmitted from the network to the UE via RRC configuration signaling, MAC signaling, and, in some embodiments, DCI. For example, RRC signaling configures SRS port resources indexed 0-7 of UE1 as SRS ports 0-7 of UE1, SRS port resources indexed 0-7 of UE2 as SRS ports 0-7 of UE2, SRS port resources indexed 8-15 of UE3 as SRS ports 0-7 of UE3, and SRS port resources indexed 8-15 of UE4 as SRS ports 0-7 of UE4, and so on. This design can also be used for UE-specific DCIs (e.g., DCI format 1-1, enhancements to 1-1 (discussed in detail below), etc.) for A-SRS triggering. The DCI may have an antenna port indication field for A-SRS; in some embodiments, this field may also be used for antenna port indication of the PDSCH, and the UE maps the port indicated in this field to a predefined SRS port resource allocated to the UE. For example, UE1 can receive an enhanced DCI of 1-1, where the antenna port indication field of PDSCH and SRS has an indication value of 25 (as shown in Table 7.3.1.2.2-2 of TS 38.212, v16.2.0, 2020-06 (which is incorporated herein by reference), reproduced below; where dmrs-Type=1, maxLength=2, which are also transmitted to the UE for use in PDSCH), which corresponds to PDSCH DMRS ports 2 and 6 and SRS ports 2 and 6, and is also mapped to SRS port resources 2 and 6. As another example, UE3 can receive an enhanced DCI of 1-1, where the antenna port indication field of PDSCH and SRS has an indication value of 25, which corresponds to PDSCH DMRS ports 2 and 6 and SRS ports 2 and 6, and is further mapped to SRS port resources 10 and 14.

[0200] Table 7.3.1.2.2-2 in TS 38.212 v16.2.0: Antenna Port (1000+DMRS Port), dmrs-Type=1, maxLength=2

[0201]

[0202]

[0203] In one example, considering a communication system with four UEs, the network can assign a first port to the first UE, two subsequent ports to the second UE, and so on. In another embodiment, the network can reuse DMRS port mapping or CSI-RS port mapping.

[0204] In one embodiment, SRS resources are configured for all Resource Block Groups (RBGs), but scheduling or group DCI allows different UEs to be scheduled on different RBGs.

[0205] Related to the UE identifier, the UE identifier is used to reduce DCI signaling overhead. In one embodiment, to further reduce the DCI size, a unique but shorter UE identifier is assigned to each pre-scheduled UE. Instead of using a long UE identifier that can be 10 or more bits long, such as a Radio Network Temporary Identifier (RNTI), a short UE identifier, unique among the pre-scheduled UEs, is assigned to each pre-scheduled UE. For example, if there are a maximum of 16 pre-scheduled UEs, the short UE identifier can be as short as 4 bits, and if there are a maximum of 8 pre-scheduled UEs, the short UE identifier can be as short as 3 bits. In one embodiment, the short UE identifier can be assigned by the access node and transmitted to the pre-scheduled UEs using RRC messaging, MAC CE messaging, higher-layer messaging, etc.

[0206] Related to the indication of the UE identifier, the access node can send a DCI trigger to the pre-scheduled UE. The indication of the pre-scheduled UE can be included in a dedicated field of the DCI. Furthermore, the UE identifier and the UE identifier field in the DCI can be configured using higher-layer signaling.

[0207] By using the UE identifier, a pre-scheduled UE can decode the DCI identified by its UE ID. Pre-scheduled UEs that can decode the DCI identified by their UE ID are considered triggering UEs. Configurable but not triggered UEs can also attempt to decode the DCI, but they will fail because the DCI does not address them, and therefore they will not be triggered.

[0208] Because new UEs are pre-scheduled or there is an additional set of active UEs, for example, UE identifiers can be updated and reconfigured through higher-level configuration.

[0209] As mentioned earlier, there may be a correlation between the SRS and the DL reference signal. For the UE to receive precoded (or uncoded) CSI-RS, the UE needs to know which CSI-RS ports have been allocated; therefore, a CSI-RS port indication needs to be sent to the UE. After receiving the CSI-RS port indication, the UE can (e.g., based on the CSI-RS port indication) infer the pre-configured CSI-RS port used for measuring the downlink channel and the SRS port used for transmitting the SRS, because the SRS and CSI-RS resources are pre-configured and there is a correlation between the SRS and CSI-RS resources.

[0210] Similarly, the UE needs to know which DMRS ports have been allocated to it. A DMRS port indication needs to be sent to the UE. After receiving the DMRS port indication, the UE can (e.g., based on the DMRS port indication) infer the pre-configured DMRS port used for measuring the downlink channel and the SRS port used for transmitting SRS, because the SRS and DMRS resources are pre-configured and there is an association between them.

[0211] In one embodiment, the SRS indication field, which indicates the specific arrangement of SRS resources or ports, is also used to indicate to the UE the mapping between uplink and downlink ports (e.g., DMRS or CSI-RS ports). Since the SRS ports for each UE are identified, the UE can infer the associated ports in the downlink from the configuration (mapping). In this case, the association between uplink and downlink ports can be configured through higher-level configuration. Fixed mappings that identify associations can be defined; for example, a one-to-one mapping between uplink and downlink ports can be configured. In another embodiment, the arrangement between uplink and downlink ports can be used as the mapping. This arrangement can be specified by the operator of the communication system in the technical standards, or it can be specified through collaboration between the network and the UE. Thus, both the network and the UE are aware of the arrangement. When the UE determines the SRS port or layer indicated to it, the UE can measure the corresponding CSI-RS and / or DMRS for channel estimation and use the measurement results to determine the precoder for precoding the uplink SRS.

[0212] In one embodiment, the indication can be implicit. In this case, indicating an SRS resource or port may be sufficient to indicate the association due to the fixed mapping between resources. In another embodiment, the indication can be explicit. In this case, a dedicated field can be used that explicitly identifies the downlink CSI-RS or DMRS used to schedule the UE.

[0213] The DCI may have dedicated fields to indicate DMRS-SRS associations. It may also have fields to indicate CSI-RS-DMRS associations. A table can be defined in the specification that has a one-to-one mapping between uplink and downlink ports.

[0214] The number of bits used to indicate the association between a downlink port and an SRS port can be used to indicate a transmission between one or more downlink ports and an SRS port, which can be indicated by the SRS resource / port indication field.

[0215] In one embodiment, the association is used not only to indicate port associations, but also to indicate bandwidth associations (active bandwidth portion).

[0216] In addition to the parameters mentioned above (e.g., UE identifier, association, and SRS resource indication), group DCI may also include some or all of the following:

[0217] - Resource allocation field, indicating time and frequency resources (e.g., the UE's resource block group);

[0218] - Explicit indication of the CSI-RS or DMRS port using a dedicated field in the DCI can indicate the downlink port. This can also be used by the UE to determine the rank of the transmission. In one embodiment, the UE can infer the rank of the uplink transmission based on downlink reception;

[0219] - Transmission power commands used for SRS transmission power control.

[0220] Figure 6 and 7Example mappings 600 and 700 for RGB 605, 607, 705, and 707, as well as SRS resources and ports, are shown. 600 illustrates RGB 605 and 607 in a communication system with the following configuration: assuming DMRS type 1 (8 ports per RGB per cell for all paired UEs); in another embodiment, a 12-port DMRS can be considered, with the 8 ports associated with 8 SRS port resources selected from n available port resources (e.g., n = 48 for comb 4, n = 16 for comb 2). The SRS port resources can be arranged similarly to those shown for RBG1 605 and RBG2 607, and each port resource can be assigned a global index, such as (2,9) for (COMB shift = 2, cyclic shift = 9), meaning the global index can be the same for different RBGs, or (1,2,9) for (RBG = 1, COMB shift = 2, cyclic shift = 9), meaning the global index is an RBG-specific index. In some embodiments, other time / frequency resource groups can be used instead of RBGs, such as (RBG, OFDM symbol), PRB, every 4 RBGs, etc. SRS from neighboring cells should be multiplexed across n SRS port resources. Indicate to the UE which 1, 2, or 4 of the available n SRS port resources require more bits than are available in the DCI message.

[0221] 700 shows RGB 705 and 707, which have the same... Figure 6 The same configuration discussed earlier. In one embodiment, the UE group CSI-RS or DMRS design is applied to the SRS. For each cell, there are only 8 predefined SRS port resources (in... Figure 7The different shaded and patterned blocks in the SRS port resource area (shown as RGB) are then used. Then, in a DCI message (such as a group DCI message or a UE-specific DCI message), a tier or port allocation for the UE is made within the eight predefined SRS port resources, and indicated accordingly. For example, SRS resources are configured for all active UEs in cell 1 (shown as unshaded blocks in the SRS port resource area as RGB), and the SRS resources have the same eight ports. That is, the SRS ports indicated to the UEs configured with SRS port resources are mapped to the SRS port resources in a one-to-one manner. The group DCI message indicates which of the eight ports are assigned to a specific UE. For example, the rank [1, 2, 4, 1] is indicated for UEs 1, 2, 3, and 4, without indicating the tier index. Another example is the use of DMRS port mapping for resources. SRS resources are configured for all RGB, but scheduling or group DCI allows different UEs to be scheduled on different RGB. In one embodiment, the SRS port resources allocated to a UE (or cell) are discontinuous, as shown in the figure. Specifically, a UE in CELL1 may not be allocated COMB shift = 1 and cyclic shifts from 1 to 12. Instead, the UE's port resources are distributed (spread out) in the figure, for example, (COMB shift = 1, cyclic shift = 1), (COMB shift = 1, cyclic shift = 7), (COMB shift = 2, cyclic shift = 1), (COMB shift = 2, cyclic shift = 7), (COMB shift = 3, cyclic shift = 1), (COMB shift = 3, cyclic shift = 7), (COMB shift = 4, cyclic shift = 1), and (COMB shift = 4, cyclic shift = 7). The advantage is that the ports of a UE or cell are more dispersed across potential SRS port resources, reducing potential interference / overlap between cyclic shifts that are close to each other.

[0222] Alternative designs for the group DCI used to transmit SRS control information are possible. In one embodiment, UEs identified in the group DCI share a resource allocation field (type 0 or type 1 indication). This may occur in a multi-user multiple-input multiple-output (MU-MIMO) setup where UEs can share resource blocks or RBGs. In this case, pre-configured UEs that have not been pre-scheduled have a field in the group DCI with a trigger set to zero.

[0223] In another embodiment, the UEs identified in the group DCI have a separate field indicating the resource allocation field for each UE. In this case, pre-configured UEs that have not been pre-scheduled have a field with the trigger set to zero.

[0224] In any of the foregoing embodiments, the UE identifier can be used to identify the pre-scheduled UE. Thus, only the pre-scheduled UE can decode the DCI. However, the UE will attempt to decode the DCI to check if the DCI was triggered (pre-scheduled). For example, all UEs detecting the DCI can attempt to decode it.

[0225] In any of the foregoing embodiments, the DCI includes a combination of the listed fields or a subset of the aforementioned fields.

[0226] In another embodiment, the modified DCI format, such as DCI format 0_1 ​​(UL granted) or DCI format 1_1, can be used to dynamically configure a triggered (pre-scheduled) UE with the above-mentioned SRS parameters and associated downlink PDSCH and / or CSI-RS parameters.

[0227] Any 5G NR DCI design can be used to indicate the necessary content mentioned above, such as adding / modifying necessary fields to the DCI.

[0228] Figure 8 The message 800 is shown, which is exchanged by the communication devices performing interference detection. 800 shows the message exchanged by access node 805 and UEs 810 and 812 when the communication devices perform interference detection (also known as training or BIT).

[0229] UEs 810 and 812 transmit uplink SRS (boxes 815 and 817). Uplink SRS can be uncoded and periodic. The uplink SRS is transmitted to access node 805. Access node 805 estimates the uplink channel (box 820). The estimation of the uplink channel is based on the uplink SRS transmitted by the UE. The access node pre-schedules the UE (box 825). UE pre-schedule can be based on signal quality metrics, CQI, PMI, or feedback, as discussed earlier. Figure 8 In the example shown, UEs 810 and 812 are also pre-scheduled UEs.

[0230] Access node 805 transmits control information (block 830) for configuring uplink SRS for the pre-scheduled UE. For example, this control information may be transmitted in a group DCI or a unicast DCI. In one embodiment, the group DCI may include the UE identifier of the pre-scheduled UE. The control information may include (and a subset thereof may also be) configuration information for the UE, such as the transmission bandwidth of the uplink SRS, or a portion thereof, an indication of the transmission port of the uplink SRS, an indication of the SRS resources or ports of the uplink SRS, implicit or explicit indications of cyclic shift and comb, subbands of the uplink SRS, SRS triggers, CSI-RS triggers, DMRS triggers, mappings between CSI-RS and SRS, and indications of mappings between DMRS and SRS, etc.

[0231] If access node 805 needs to transmit CSI-RS, then access node 805 transmits CSI-RS (box 835). UEs 810 and 812 can perform downlink channel estimation (boxes 840 and 842). Downlink channel estimation can be performed based on the CSI-RS transmitted by access node 805.

[0232] UEs 810 and 812 transmit uplink SRS (boxes 845 and 847). The uplink SRS is transmitted based on configuration information transmitted by access node 805. The uplink SRS can be precoded, for example, based on a singular value decomposition (SVD) precoder. Access node 805 determines the interference covariance matrix (box 850). The interference covariance matrix is ​​determined based on the uplink SRS transmitted by UEs 810 and 812 (i.e., the pre-scheduled UEs). Access node 805 determines the downlink precoder (box 855). The downlink precoder is determined based on the interference covariance matrix. Access node 805 transmits downlink data to UEs 810 and 812 (box 860). For example, access node 805 uses the downlink precoder associated with the pre-scheduled UE to precode the downlink data for each pre-scheduled UE. The precoded downlink data is transmitted via the physical downlink shared channel (PDSCH).

[0233] In the 3GPP Fifth Generation (5G) New Radio (NR) standard associated with existing DCI formats, the DCI size is minimized to reduce communication overhead. For example, in DCI format 2_3, used to transmit group transmit power control (TPC) commands used by one or more UEs for SRS transmission, the DCI size is less than or equal to the DCI size of DCI format 1_0. Therefore, the number of bits available for transmitting uplink SRS configuration is limited. However, existing DCI formats do not support dynamic signaling for SRS configuration. Furthermore, control information must be provided for all configured UEs, even those that are not triggered (i.e., not pre-scheduled) to transmit uplink SRS; therefore, the number of UEs configured using existing DCI formats is limited due to the bit limitation.

[0234] According to an example embodiment, a DCI format for transmitting SRS configuration information is provided. In one embodiment, the DCI includes SRS configuration information only for pre-scheduled UEs. Existing DCI formats include control information for all configured UEs, even those that are not pre-scheduled. Making the DCI include only SRS configuration information for pre-scheduled UEs reduces the size of the DCI, thereby allowing for a reduction in DCI size or the inclusion of more SRS configuration information.

[0235] Figure 9 The first example DCI 900 is shown. Figure 9 As shown, DCI 900 is an example of a DCI, where the DCI includes SRS configuration information used only for pre-scheduled UEs, and a short UE identifier is used to identify the UE. DCI 900 includes an identification field 905, which identifies that the DCI is used to transmit SRS configuration information to the pre-scheduled UEs. DCI 900 also includes SRS configuration information for each pre-scheduled UE, such as a first pre-scheduled UE 910, a second pre-scheduled UE 912, and an Nth pre-scheduled UE 914.

[0236] As an example of savings achievable by using a short UE identifier and transmitting information only for pre-scheduled UEs, consider a scenario where an access node is serving 20 UEs, of which only 5 are pre-scheduled. If a 10-bit long RNTI were used, the DCI format would require transmitting at least [number missing] UEs separately. However, if a short UE identifier and a pre-scheduled UE are used, DCI format 700 will only need to transmit bit identification information. The identifier information of the bit.

[0237] For each pre-scheduled UE, such as the first pre-scheduled UE 910, the DCI 900 includes a UE ID field 920, a resource allocation field 922, an SRS TPC command field 924, and an SRS indication field 926. The UE ID field 920 includes a short UE identifier for the pre-scheduled UE and may be, for example, 4 bits in size. The resource allocation field 922 includes time and frequency resource blocks or groups for the pre-scheduled UE. The size of the resource allocation field 922 may depend on the type of resource allocation and the bandwidth part (BWP) size, which also depends on, for example, the resource allocation type. The SRS TPC command field 924 includes power control commands for SRS and may be, for example, 2 bits in size. The SRS indication field 926 includes SRS resources, SRS ports, SRS transmission bandwidth, etc. The values ​​in the SRS indication field 926 can be pre-configured with a set of different possible arrangements of SRS resources or ports, SRS transmission bandwidth, etc., and the SRS indication field 926 only stores indexes for a specific set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., to reduce size. The SRS indication field 926 can also be used to indicate mappings to DL ports (layers, reference signals, etc.). The example SRS indication field 926 is 4 bits in size. The SRS indication field 926 supports uplink SRS port indication for SRS transmission. It also implicitly indicates SRS cyclic shift, SRS subband, SRS comb, etc. It also implicitly indicates the precoded CSI-RS port (e.g., the same port) assigned to the pre-scheduled UE in the downlink. The example sizes of the various fields of DCI 900 are for illustrative purposes only. The example embodiments presented herein can operate with other field sizes.

[0238] Related to resource allocation fields, such as resource allocation field 922, resource type 1 can be used for frequency allocation. Alternatively, resource type 2 can be used for frequency allocation. Resource block groups can be used by the UE. Furthermore, frequency allocation can include allocations for SRS transmissions.

[0239] The indication to the UE related to the downlink antenna port can be used for the downlink port or the downlink layer. As an example, the indication can be a bitmap. As another example, the indication can be a value. The UE can determine whether to use the CSI-RS or DMRS port based on the SRS port assigned to the UE. As an example, the indication can use an SRS indication field. In another embodiment, the indication to the SRS port can use a bitmap.

[0240] Information associated with a configured UE that has not been pre-scheduled is not included in DCI format 900. A pre-scheduled UE can process the DCI to determine whether the access node has triggered the pre-scheduled UE for SRS transmission.

[0241] In one embodiment, to further reduce the DCI size, the SRS configuration information for each pre-scheduled UE is arranged sequentially (e.g., in ascending or descending order), so that the short UE identifier does not need to be included in the DCI. Therefore, a further reduction in DCI size is achieved.

[0242] In one embodiment, time and frequency resource blocks or groups are configured for the pre-scheduled UE. Figure 9 In this implementation, each pre-scheduled UE can be configured with different allocations of time and frequency resource blocks or groups. In this embodiment, a single allocation of time and frequency resource blocks or groups is configured for the pre-scheduled UE indicated in the DCI. In one embodiment, a single DCI is used to transmit SRS configuration information for the pre-scheduled UEs of the access node. In this case, the DCI includes an SRS TPC command and an SRS indication for each pre-scheduled UE. The SRS TPC command and SRS indication for each pre-scheduled UE can be arranged according to the short UE identifier assigned to each pre-scheduled UE. For example, the SRS TPC command and SRS indication for each pre-scheduled UE can be arranged in ascending or descending order of the short UE identifier.

[0243] In one embodiment, a single DCI is used to transmit SRS configuration information for a subset of pre-scheduled UEs for the access node. In this case, the DCI includes SRS TPC commands and SRS indications for each pre-scheduled UE in the subset. For example, a first DCI includes SRS TPC commands and SRS indications for a first subset of pre-scheduled UEs, a second DCI includes SRS TPC commands and SRS indications for a second subset of pre-scheduled UEs, and so on. The SRS TPC commands and SRS indications for each pre-scheduled UE in the subset can be arranged according to a short UE identifier assigned to each pre-scheduled UE in the subset. For example, the SRS TPC commands and SRS indications for each pre-scheduled UE in the subset can be arranged in ascending or descending order of short UE identifiers.

[0244] Figure 10 A second example of DCI 1000 is shown. (e.g.) Figure 10As shown, DCI 1000 is an example of a DCI in which a single allocation of time and frequency resource blocks or groups is configured for a pre-scheduled UE. DCI 1000 includes an identification field 1005, which identifies that the DCI is used to transmit SRS configuration information to the pre-scheduled UE, and a resource allocation field 1010. The resource allocation field 1010 includes the time and frequency resource blocks or groups for the pre-scheduled UE indicated in DCI 1000. DCI 1000 also includes SRSTPC commands and SRS indications for each pre-scheduled UE (e.g., first pre-scheduled UE 1015, second pre-scheduled UE 1017, and Nth pre-scheduled UE 1019).

[0245] For each pre-scheduled UE, such as the first pre-scheduled UE 1015, the DCI 1000 includes an SRS TPC command field 1025 and an SRS indication field 1027. The SRS TPC command field 1025 includes a power control command for SRS and may be, for example, 2 bits in size. The SRS indication field 1027 includes SRS resources, SRS ports, SRS transmission bandwidth, etc. The values ​​in the SRS indication field 1027 may be pre-configured with a set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., and only indices to a specific set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., are stored in the SRS indication field 1027 to reduce size. An example SRS indication field 1027 is 4 bits in size. The SRS indication field 1027 supports uplink SRS port indication for transmitting SRS. It also implicitly indicates the precoded CSI-RS port (e.g., the same port) assigned to the pre-scheduled UE in the downlink. It also implicitly indicates SRS cyclic shift, SRS sub-band, SRS comb, etc.

[0246] In one embodiment, to further reduce the DCI size, time and frequency resource block or group allocations are configured for pre-scheduled UEs. Time and frequency resource block or group allocations can be configured for pre-scheduled UEs scheduled for SRS transmission. Therefore, in this case, time and frequency resource block or group allocations are included for each pre-scheduled UE scheduled for SRS transmission, and the allocation of time and frequency resource blocks or groups is omitted for each pre-scheduled UE not scheduled for SRS transmission.

[0247] Figure 11 The third example, DCI 1100, is shown. (As...) Figure 11As shown, DCI 1100 is an example of a DCI in which time and frequency resource blocks or groups are allocated for each pre-scheduled UE scheduled for SRS transmission. DCI 1100 includes an identification field 1105 that identifies the DCI as being used to transmit SRS configuration information to the pre-scheduled UEs. DCI 1100 also includes information for each pre-scheduled UE (e.g., first pre-scheduled UE 1110, second pre-scheduled UE 1112, and Nth pre-scheduled UE 1114). This information may vary depending on the pre-scheduled UE; for example, pre-scheduled UEs scheduled for SRS transmissions are compared to pre-scheduled UEs not scheduled for SRS transmissions.

[0248] For each pre-scheduled UE scheduled for SRS transmission, such as the first pre-scheduled UE 1110, DCI 1100 includes a resource allocation field 1120, an SRS TPC command field 1122, and an SRS indication field 1124. The resource allocation field 1120 includes time and frequency resource blocks or groups for the pre-scheduled UE. The size of the resource allocation field 1120 can depend on the type of resource allocation and the BWP size, and can be, for example, 10 bits. The SRS TPC command field 1122 includes power control commands for SRS, and can be, for example, 2 bits. The SRS indication field 1124 includes SRS resources, SRS ports, SRS transmission bandwidth, etc. The values ​​in the SRS indication field 1124 can be pre-configured with a set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., and the SRS indication field 1124 only stores indices to a set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., to reduce size. An example SRS indication field 1124 is 4 bits in size. SRS indication field 1124 supports SRS port indication in the uplink for transmitting SRS. It also implicitly indicates the precoded CSI-RS port (e.g., the same port) assigned to the pre-scheduled UE in the downlink. It also implicitly indicates SRS cyclic shift, SRS subband, SRS comb, etc. The example sizes of the various fields in DCI 1100 are for illustrative purposes only. The example embodiments presented herein may work with other field sizes.

[0249] For each pre-scheduled UE not scheduled for SRS transmission, such as the Nth pre-scheduled UE 1114, the resource allocation field 1130, the SRS TPC command field 1132, and the SRS indication field 1134 are set to zero or some other specified value. Although Figure 11 The example shown is that the Nth pre-scheduled UE 1114 is a pre-scheduled UE that is not scheduled for SRS transmission, but any of the N pre-scheduled UEs in DCI 1100 can be a pre-scheduled UE that is not scheduled for SRS transmission.

[0250] Figure 9-11 The example embodiments shown are for group DCI. However, the example embodiments presented herein can also be used for unicast DCI. In unicast DCI, the DCI is specifically addressed to a single UE. Addressing the DCI to a specific UE can be accomplished by encoding the DCI using the UE's identifier. When the DCI is encoded using the UE's identifier, only that UE can decode the DCI, while other UEs will detect the encoded DCI as noise. Since the DCI is specifically addressed to the UE using the UE's identifier, the DCI does not need to include the UE's unique identifier. Therefore, the size of the DCI is reduced.

[0251] Figure 12 The fourth example, DCI 1200, is shown. (As...) Figure 12 As shown, DCI 1200 is an example of a DCI used in unicast DCI. DCI 1200 includes an identification field 1205, a resource allocation field 1210, an SRS TPC command field 1215, and an SRS indication field 1220. The identification field 1205 identifies that the DCI is used to transmit SRS configuration information to the pre-scheduled UE. The resource allocation field 1210 includes time and frequency resource blocks or groups for the pre-scheduled UE. The size of the resource allocation field 1210 can depend on the type of resource allocation and the BWP size, and can be, for example, 10 bits. The SRS TPC command field 1215 includes power control commands for SRS, and can be, for example, 2 bits. The SRS indication field 1220 includes SRS resources, SRS port, SRS transmission bandwidth, etc. The values ​​in the SRS indication field 1220 can be pre-configured with a set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., and the SRS indication field 1220 only stores indices for a set of possible SRS resources, SRS ports, SRS transmission bandwidth, etc., to reduce size. The example SRS indication field 1220 is 4 bits in size. The SRS indication field 1220 supports uplink SRS port indication for transmitting SRS. It also implicitly indicates the precoded CSI-RS port (e.g., the same port) assigned to the pre-scheduled UE in the downlink. It also implicitly indicates SRS cyclic shift, SRS subband, SRS comb, etc. The example sizes of the various fields of DCI 1200 are for illustrative purposes only. The example embodiments presented herein can operate with other field sizes.

[0252] In another embodiment, dynamic signaling using fields (or more) in the DCI can be used to transmit the identifier of a reference downlink resource (or more resources). Higher-layer signaling can be used to configure dedicated fields for transmitting mappings from a configured fixed mapping.

[0253] Figure 13A flowchart of an example operation 1300 performed in a UE is shown. Operation 1300 can indicate the operations performed in a UE when the UE participates in interference detection and receives downlink data. The UE can be a pre-scheduled UE.

[0254] Operation 1300 begins with the UE transmitting uplink SRS (box 1305). The uplink SRS may be uncoded. The uplink SRS may be substantially periodic. The UE receives DCI from the access node (box 1307). The DCI may include SRS configuration information for the UE. The SRS configuration information configures the UE to perform SRS transmission. The DCI may also include CSI-RS configuration. The DCI may be part of a group DCI message. The DCI may be a unicast DCI message. The UE estimates the downlink channel (box 1309). The UE uses the CSI-RS transmitted by the access node to estimate the downlink channel. The UE transmits precoded SRS (box 1311). The precoded SRS is transmitted based on the SRS configuration information received in the DCI. The UE receives downlink data (box 1313). The downlink data is received from the access node. The downlink data is precoded using a precoder determined based on the precoded SRS transmitted by the UE.

[0255] Figure 14 A flowchart of an example operation 1400 performed in an access node is shown. Operation 1400 can indicate the operations performed in the access node when it participates in interference detection and transmits downlink data.

[0256] Operation 1400 begins with the access node estimating the uplink channel (box 1405). For example, the access node uses the SRS transmitted by the UE to estimate the uplink channel. The SRS can be pre-coded or uncoded. The access node pre-schedules the UE (box 1407). The access node pre-schedules the UE based on the SRS transmitted by the UE. For example, the access node pre-schedules the UE associated with an SRS whose signal quality exceeds a specified threshold. The access node transmits a DCI to the pre-scheduled UE to trigger SRS transmission (box 1409). The DCI transmitted by the access node may also cause the UE to measure downlink CSI-RS or DMRS. The access node configures the SRS for the pre-scheduled UE and sends SRS configuration information to the pre-scheduled UE in the DCI. The SRS configuration information may also include CSI-RS information. The DCI can be a group DCI or a unicast DCI.

[0257] The access node can transmit CSI-RS (Box 1411). CSI-RS can be used for downlink channel estimation. The access node receives precoded SRS (Box 1413). Precoded SRS can be received according to SRS configuration information. The access node determines the interference covariance matrix (Box 1415). The interference covariance matrix is ​​determined based on the precoded SRS. The access node determines the downlink precoder (Box 1417). The downlink precoder is determined based on the interference covariance matrix. The access node transmits downlink data (Box 1419). The downlink data is precoded according to the downlink precoder.

[0258] Figure 15 A flowchart illustrating example operation 1500 performed in an access node configured with uplink SRS is shown. Operation 1500 can indicate the operations performed in the access node when the access node configures uplink SRS and receives uplink SRS transmissions.

[0259] Operation 1500 begins with the access node transmitting SRS configuration (box 1505). SRS configuration can be transmitted in downlink control information, such as in group DCI or unicast DCI. When using group DCI, the group DCI can be addressed to the UE using a UE identifier (e.g., a pre-scheduled UE). The UE identifier is unique within the UE group but shorter than a typical UE identifier, thus saving signaling overhead. In one embodiment, the SRS configuration includes information about the arrangement of SRS port resources (e.g., combs, offsets, cyclic shifts, symbols, etc.). SRS port resources can also be divided into multiple resource groups. In one embodiment, the SRS configuration includes a set of SRS ports within the SRS resources. In one embodiment, the SRS configuration includes information about the association between SRS port resources and downlink port resources (e.g., CSI-RS ports, DMRS ports, etc.). Information about mappings between ports may also be included.

[0260] The access node transmits an indication of SRS resources (box 1507). In one embodiment, the indication of SRS resources indicates a group of SRS resources for uplink SRS transmission. In one embodiment, the indication of SRS resources indicates a subset of SRS ports in the SRS resources for uplink SRS transmission. In one embodiment, the indication of SRS resources indicates an association for determining the SRS ports used for uplink SRS transmission. The indication of SRS resources may be transmitted in downlink control information, such as in group DCI or unicast DCI. When using group DCI, the UE identifier is used (as described above). The indication of SRS resources may be included in a message transmitted after the transmission of SRS configuration. The message including the indication of SRS resources may be the first message transmitted after the transmission of SRS configuration. The access node receives the uplink SRS (box 1509). The uplink SRS is received according to the indicated SRS resources.

[0261] Figure 16 A flowchart illustrating example operation 1600 performed in a UE transmitting uplink SRS is shown. Operation 1600 can indicate the operations performed in the UE when the UE receives uplink SRS configuration and transmits uplink SRS.

[0262] Operation 1600 begins with the UE receiving the SRS configuration (box 1605). The SRS configuration can be received in downlink control information, such as in group DCI or unicast DCI. When using group DCI, the group DCI can be addressed to the UE using a UE identifier (e.g., a pre-scheduled UE). The UE identifier is unique within the UE group but shorter than a typical UE identifier, thus saving signaling overhead. In one embodiment, the SRS configuration includes information about the arrangement of SRS port resources (e.g., combs, offsets, cyclic shifts, symbols, etc.). SRS port resources can also be divided into multiple resource groups. In one embodiment, the SRS configuration includes a set of SRS ports within the SRS resources. In one embodiment, the SRS configuration includes information about the association between SRS port resources and downlink port resources (e.g., CSI-RS ports, DMRS ports, etc.). Information about mappings between ports may also be included. Even if the UE is not the intended recipient of the SRS configuration, the UE will still receive the downlink control information and attempt to decode it.

[0263] The UE receives an indication of SRS resources (block 1607). In one embodiment, the indication of SRS resources indicates a group of SRS resources for uplink SRS transmission. In one embodiment, the indication of SRS resources indicates a subset of SRS ports in the SRS resources for uplink SRS transmission. In one embodiment, the indication of SRS resources indicates an association for determining the SRS ports used for uplink SRS transmission. The indication of SRS resources may be received in downlink control information, such as in group DCI or unicast DCI. When using group DCI, the UE identifier is used (as described above). The indication of SRS resources may be included in a message received after the reception of SRS configuration. The message including the indication of SRS resources may be the first message received after the transmission of SRS configuration. The UE transmits uplink SRS (block 1609). Uplink SRS is transmitted according to the indicated SRS resources.

[0264] Some embodiments of flexible A-SRS triggering for BiT described above may result in higher DCI overhead because it includes more bits in the SRS request field. Furthermore, A-SRS triggering may occur more frequently, such as every time a MU scheduling occurs. To reduce DCI overhead, several embodiments are provided. First, a more flexible framework for segmenting SRS transmission parameter information among RRC configuration signaling, MAC CE, and DCI would be useful. The impact of the minimum standard is to retain as much SRS transmission parameter information as possible in RRC and MAC, and for the DCI to contain only the minimum parameter information required for dynamic signaling. Additionally, existing DCIs can be enhanced to include new fields and be associated with new UE behaviors.

[0265] An example of reducing overhead based on group common DCI is provided.

[0266] BiT probing is designed to support PDSCH with MU-MIMO, where multiple UEs are paired together in the PDSCH and its DMRS. Therefore, BiT probing should be a "mirror image" of the PDSCH DMRS. For example, we know that for PDSCH DMRS type 1, a maximum of 8 DMRS ports / RBGs / cells can be supported. Correspondingly, 8 SRS port resources can be segmented and assigned to multiple UEs, where the SRS port resources are for OFDM symbols of cyclic shifts, combs, and shifts, and possibly cell RBGs. A mapping (i.e., association) from DL DMRS ports to SRS port resources can then be designed, and port information can be transmitted to the UEs via SRS triggers. This can be done in an overhead-efficient manner using GC DCI, where the GC DCI is sent to a group of UEs that may be paired for MU transmission in a time slot. The GC DCI can trigger SRS to be transmitted from the UE simultaneously, i.e., a common trigger offset can be used. Furthermore, other fields, such as CMR / IMR indications, can be included, and the design can be similar to the CSI request field in DCI format 0_1. One embodiment is a GC DCI for flexible A-SRS triggering with reduced overhead, whereby the GC DCI is sent to a group of UEs that may be paired for MU transmissions in a time slot. These UEs share a common trigger offset, and each UE is assigned a UE-specific Frequency Domain Resource Allocation (FDRA), port allocation (relative to the available SRS port resources of its serving cell, such as cyclic shift, comb, and shift), and CMR / IMR indication. In one embodiment, the GC DCI includes a new field for the A-SRS trigger offset with time slot offset k0 and symbol position. In another embodiment, the GC DCI includes a new field for A-SRS beamforming with dynamic indication of DL CMR and / or IMR, similar to the CSI request field in DCI format 0_1. In one embodiment, if A-SRS is assigned an FDRA and / or port allocation, the UE assumes higher priority for A-SRS in the GC DCI. In one embodiment, by simply indicating the rank of the paired UEs (the number of data layers or the number of SRS / DMRS ports), a UE-specific port allocation field is used to replace the group common (joint) port allocation field of all UEs paired on the RBG (or associated frequency domain unit). (The UE order may be indicated elsewhere, or the UE ID may also be included along with the rank allocation.) In this embodiment, the UE ports must follow a certain pattern, such as continuous or uniform distribution, but as long as the rank is indicated, each UE can determine its SRS port resources.

[0267] Table 1 below provides enhancements to DCI 1-1 for SRS detection.

[0268] Table 1

[0269]

[0270] The limitations of enhanced DCI 1-1 include:

[0271] - Some fields are marked "Already used for PDSCH". This may now also apply to SRS.

[0272] However, it is unclear under what conditions these PDSCH fields also apply to SRS.

[0273] -DCI does not require a CSI request. However, for BiT systems with DL probing to improve link adaptation, a CSI request is required.

[0274] - Furthermore, there is not much detailed description regarding SRS detection to enhance UL DCI 0_1.

[0275] An embodiment of UE-specific DCI overhead reduction is provided. To reduce DCI overhead, one embodiment uses DL DCI format 1_0 / 1_1 for both A-SRS triggering and PDSCH scheduling, with SRS and PDSCH having the same PRB / port allocation. In DCI format 1_0 or 1_1, it already has fields for: 1) A-SRS trigger, 2) PDSCH PRB allocation dynamically indicated via the DLFDRA field, 3) dynamically indicated PDSCH port, 4) a field indicating possible PRB bundle size (as in DCI format 1_1), etc. These fields can be used by the UE for (reused for) SRS triggering. New fields are also added for BiT purposes, such as SRS resource indication, SRS trigger offset (similar to PDSCH SLIV), and a CMR / IMR indication field, which may be similar to the CSI request field as in DCI format 0_1. The UE assumes that FDRA and port also apply to triggered SRS, which can significantly reduce DCI overhead. For port indication, a mapping (association) from the DCI DL port indication to the SRS port is required (in terms of cyclic shift, comb, and shift), which can be defined in Rel-17. One embodiment reuses the UE-specific DCI (e.g., format 1_1) and introduces new fields for overhead-reduced flexible A-SRS triggering. The UE first performs A-SRS transmission based on existing fields of FDRA, port indication, and PRB bundle size indication, and new fields of SRS resource indication, SRS trigger offset, and CMR / IMR indication. The UE then performs PDSCH reception based on at least the same FDRA and port indication in the same DCI. In one embodiment, the UE-specific DCI includes a new field for A-SRS trigger offset with slot offset k0 and symbol position. In one embodiment, the UE-specific DCI includes a new field for A-SRS beamforming with dynamic indication of DL CMR and / or IMR, similar to the CSI request field in DCI format 0_1. In one embodiment, if A-SRS is assigned FDRA and / or port allocation, the UE assumes higher priority for A-SRS in the UE-specific DCI. In one embodiment, the UE supports more receive antenna ports (e.g., for PDSCH and its DMRS) than transmit antenna ports (e.g., for SRS). For example, the UE may only probe on one port. In this case, the UE should ignore the PDSCH port indication and probe only on one port. As another example, the UE may only probe on two ports but can receive on up to four ports. In this case, the UE can still utilize the PDSCH port indication information; that is, if the PDSCH has only one layer, it probes on one port, but if the PDSCH has two or more layers, it probes on two ports.In one embodiment, port indication for SRS is not supported, but rank (number of ports or number of layers) indication is supported. That is, the UE uses the rank indication of SRS (or PDSCH) for SRS transmission. The port associated with this rank is predetermined according to the standard or RRC configuration.

[0276] Implementations supporting UE-specific DCI-based and GC DCI-based overhead reduction are provided for flexible A-SRS triggering for interference detection. In one embodiment, the GC DCI is an enhanced GC DCI format 2_3 with UE FDRA and port indication. In another embodiment, the UE-specific DCI is an enhanced DL DCI format 1_0 / 1_1, used to reinterpret existing FDRA / port indication fields for SRS transmission. In one embodiment, both embodiments are supported. In yet another embodiment, enhanced GC DCI and / or UE-specific DCI are supported, becoming a new DL DCI format. In any embodiment, a new field for A-SRS trigger offset with slot offset k0 and symbol position may be included. In any embodiment, a new field for A-SRS beamforming with dynamic indication DL CMR and / or IMR may be included, similar to the CSI request field in DCI format 0_1. In any embodiment, if A-SRS is assigned FDRA and / or port allocation, the UE assumes higher priority for A-SRS.

[0277] In one embodiment, the GC DCI and / or UE-specific DCI are TDDs used for UL to operate in OFDM (not SC-FDMA). For proper utilization of BiT or SRS probing against DL, UL and DL should be as symmetrical as possible. Since DL is simply OFDM, it is more appropriate for UL to also be OFDM. This may also be more appropriate if the PDSCH / SRS transmission is discontinuous in the frequency domain, such as with PRB skipping, FDRA type 0 with discontinuous RBGs, interleaved VRB-to-PRB mappings, etc.

[0278] In one embodiment, the GC DCI and / or UE-specific DCI reuse the PDSCH TDRA design for its SRS trigger offset design. In another embodiment, the GC DCI and / or UE-specific DCI reuse the PUSCH TDRA for its SRS trigger offset design. In yet another embodiment, the GC DCI and / or UE-specific DCI reuse the PUSCH / PDSCH TDRA for its SRS trigger offset design, but modify the L value configuration and range to suit SRS transmission. For example, the network may configure SRS only on 8–14 OFDM symbols; therefore, the current range of L for PUSCH, 4–14 or 1–14, can be modified to 8–14, allowing the L value to be indicated using fewer bits.

[0279] In embodiments of GC DCI and / or UE-specific DCI, a new field for A-SRS beamforming with dynamically indicated DL CMR and / or IMR is included. This field can be similar to the CSI request field in DCI format 0_1, or it can reuse the same indication / configuration as the CSI request field. In one embodiment, the A-SRS beamforming field is the same as a 0, 1, 2, 3, 4, 5, or 6-bit CSI request field determined by the higher-layer parameter reportTriggerSize. SRS beamforming is not performed when all bits of the field in the DCI are set to zero. The non-zero codepoints of the field in the DCI are mapped to the CMR / IMR associated with the CSI trigger state according to: the highest... The order of the associated positions of the trigger states, where code point "1" maps to the trigger state of the first position. After the UE determines the CMR from this field, the UE also selects the CMR port according to the antenna port indication field, and the UE uses the selected CMR port and the indicated / associated IMR to generate SRS beamforming for each SRS port.

[0280] In some embodiments, a flag / switch is introduced to specify whether an A-SRS triggered by a DCI reuses some fields from a transmission scheduled / triggered by another DCI. The primary purpose of this flag is to make the DCI useful for both BiT and non-BiT purposes while minimizing redesign. For example, when the flag is set, the UE should assume that an A-SRS triggered in the DCI reuses fields of a PDSCH (e.g., FDRA) scheduled by that DCI or another DCI, but when the flag is not set, the UE should not assume that the A-SRS reuses fields from another transmission. In other words, this flag serves as an indication of whether the UE assumes an association between A-SRS parameters and another transmission.

[0281] In one embodiment, the flag / switch is a field in the DCI, meaning that associations can be dynamically indicated for full flexibility. In one embodiment, the flag is turned on / off via MAC CE. In another embodiment, the flag is turned on / off via RRC configuration in DCI format.

[0282] In one embodiment, the flag is used for a DCI that can be used to schedule PUSCH transmissions. One example could be a DCI format 0_1, which schedules PUSCH and includes fields for PUSCH transmissions, such as PUSCH FDRA, antenna port, frequency hopping, on UL (uplink carrier) or SUL (supplementary uplink carrier), on which BWP, etc. In one embodiment, the flag is used for the association of A-SRS with PUSCH. When the flag is set, A-SRS is triggered, and PUSCH is scheduled, the UE uses parameters obtained from certain PUSCH fields for SRS transmissions, and these fields may include at least one or more of PUSCH FDRA, PUSCH antenna port indication, PUSCH frequency hopping, UL / SUL indication, BWP indication, closed-loop TPC command, etc. PUSCH and A-SRS have different timings so they do not conflict; that is, A-SRS can have its own TDRA or have an offset relative to PUSCH, for example, n time slots earlier than PUSCH. However, when the flag is not set and A-SRS is triggered, the UE will not use these PUSCH fields for A-SRS transmission. In one embodiment, the flag is a field associated with the SRS request field in the DCI format. In one embodiment, the flag field contains multiple bits to indicate which PUSCH fields the UE should use for associated A-SRS, such as bits indicating whether A-SRS reuses PUSCH FDRA / BWP, and bits indicating whether A-SRS reuses PUSCH TPC commands, etc. In one embodiment, the flag is used for the association of A-SRS with PDSCH. When the flag is set and A-SRS is triggered, the UE uses parameters obtained from certain PDSCH fields for SRS transmission, and these fields may include at least one or more of PDSCH FDRA, PDSCH antenna port indication, PDSCH frequency hopping, BWP indication, PRB to VRB interleaving, etc. However, when the flag is not set and A-SRS is triggered, the UE will not use these PDSCH fields for A-SRS transmission. The associated PDSCH is not scheduled using the DCI, but the association is assigned to the UE so that the UE can link to the correct PDSCH. This can be achieved through the common ID used for SRS and PDSCH (e.g., a field with ID or DCI RNTI, etc.) or through their timing relationship (e.g., simultaneous triggering, triggering within 2 time slots, PDSCH scheduled n time slots after A-SRS, where n is 1, 2, etc.).

[0283] In one embodiment, the flag is used for a DCI that can be used to schedule PDSCH transmissions. One example could be a DCI format 1_1, which schedules PDSCHs and includes fields for PDSCH transmissions, such as PDSCH FDRA, antenna port, PRB bundle size, etc. In one embodiment, the flag is used to associate A-SRS with PDSCH within the same DCI. When the flag is set, A-SRS is triggered, and PDSCH is scheduled, the UE uses parameters obtained from certain PDSCH fields for SRS transmissions, and these fields may include at least one or more of PDSCH FDRA, PDSCH antenna port indication, PDSCH PRB bundle size, etc. However, when the flag is not set and A-SRS is triggered, the UE does not use these PDSCH fields for A-SRS transmissions. In one embodiment, the flag is a field associated with an SRS request field in the DCI format. In one embodiment, the flag field contains multiple bits to indicate which PDSCH fields the UE should use for the associated A-SRS, such as bits indicating whether the A-SRS reuses the PDSCH FDRA / BWP, and bits indicating whether the A-SRS reuses the PDSCH antenna port, etc.

[0284] In one embodiment, a DCI that can schedule PUSCH or PDSCH or trigger A-SRS may also have a CSI request field. This flag, or the flag's bit direction to the UE, indicates whether A-SRS is also associated with the CSI request field. When the flag is set, the UE can use the CMR and optional IMR associated with the CSI request to perform A-SRS beamforming. The DCI can be an extension of format 0_1 ​​or 1_1. In a DCI embodiment with PDSCH scheduling, SRS triggering, and CSI requests, A-SRS can be bound to the scheduled PDSCH (e.g., reusing PDSCH FDRA) and / or the CSI request (reusing CMR / IMR for beamforming). The CSI request can be associated with aperiodic CSI-RS transmissions. This is particularly useful for BiT, as a DCI indicates that the DL RS is performing A-SRS beamforming, A-SRS parameters shared with the PDSCH, and the PDSCH. DL RS can also be used for DL ​​probes for MCS adjustment, i.e., the UE reports CQI to the gNB but not PMI, so that the gNB can perform link adaptation for PDSCH.

[0285] In one embodiment, the uplink DCI (e.g., 0_1) of the PUSCH can indicate that the PUSCH is not scheduled via the UL-SCH indicator, i.e., the UL-SCH bit is zero. A-SRS trigger parameters can redefine fields designed for the PUSCH. For example, the A-SRS trigger offset or TDRA can use several bits. The A-SRS port indicator can use several bits. The A-SRS FDRA can use several bits. And so on.

[0286] In one embodiment, the downlink DCI (e.g., 1_1) of the PDSCH can indicate that no PDSCH is scheduled. The absence of PDSCH can be indicated by the DL-SCH indicator (i.e., the DL-SCH bit is zero), or by setting several bits in the original PDSCH field to zero, such as the downlink allocation index bit, FDRA / TDRA bits, etc. Fields designed for PUSCH can be redefined for A-SRS trigger parameters. For example, several bits can be used for the A-SRS trigger offset or TDRA. Several bits can be used for the A-SRS port indicator. Several bits can be used for the A-SRS FDRA. And so on.

[0287] In summary, UL DCI can be used for SRS triggering with or without PUSCH, with or without CSI requests, with SRS bound to or not bound to PUSCH (e.g., FDRA, etc.), with or not bound to PDSCH, with or not bound to PDSCH, and with or not bound to CSI request fields. DL DCI can also be used for SRS triggering with or without PDSCH, with or without CSI requests, with SRS bound to or not bound to PDSCH (e.g., FDRA, etc.), and with or not bound to CSI request fields.

[0288] An example of triggering SRS using a GC DCI is provided. One example is an enhanced version of the current GC DCI format 2_3. The enhanced DCI format 2_3 omits the FDRA field to reduce overhead. The DCI may include multiple SRS blocks, each of which can be used to trigger one or more SRS transmissions. Each block includes an SRS request field (optional) and one or more SRS TPC command fields (if the block can trigger multiple SRS transmissions). These blocks can be used by the same UE or by multiple UEs. Each UE receiving an SRS trigger in a block of the DCI is assumed to receive another DCI with an FDRA and uses that FDRA for the triggered SRS. The other DCI may be a UL DCI, such as 0_1 or enhanced 0_1, in which case the FDRA and possibly other fields, such as BWP indication, UL / SUL indication, frequency hopping indication, antenna port indication, etc., are also used by the UE for A-SRS transmissions. Another DCI can be a DL DCI, such as 1_1, enhanced 1_1, or 1_0, in which case FDRA and possibly other fields, such as antenna port indication, PRB bundle size indication, etc., are also used by the UE for A-SRS transmission. In one embodiment, each UE block in the GC DCI is associated with a flag / switch. When the flag is set, the UE uses the linked DCI field for A-SRS; when the flag is not set, the UE does not look for the linked DCI field for A-SRS. This flag can be a field in the GC DCI, which can be activated / deactivated via MAC CE or configured via RRC signaling. The linked DCI is assigned to the UE so that the UE can link to the correct DCI. This can be achieved through a common ID used for SRS and PDSCH (e.g., a field with an ID or DCI RNTI, etc.) or through their timing relationship (e.g., simultaneous triggering, triggering within 2 time slots, PDSCH scheduled n time slots after A-SRS, where n is 1, 2, etc.). In one embodiment, the GC DCI does not necessarily have to be used only for paired UEs. Each UE's block and the fields within the block are pre-configured via RRC signaling. When all bits of the UE's SRS request field are 0, the UE does not trigger SRS. When the UE's SRS request field is not all 0, A-SRS is triggered.

[0289] In one embodiment, in GC DCI, all triggered SRSs in GC DCI use the same TDRA field. That is, each UE does not have a UE-specific TDRA field, which saves overhead. In one embodiment, in GC DCI, several TDRA options are provided for all UEs using DCI, and each TDRA is associated with an ID. Then, in each UE's block, a field is used to indicate to the UE which TDRA should be applied based on the ID. In one embodiment, a separate TDRA field is configured for each SRS block, that is, each triggered SRS can be associated with a different TDRA. In one embodiment, SRS triggered by DCI are transmitted on the same time slot, but may be transmitted on different OFDM symbols. Then, DCI includes a group common TDRA field (e.g., k0 of the time slot offset) applied to all triggered SRS from that DCI, and a single TDRA field for each SRS block (e.g., OFDM symbol position, SLIV, etc.).

[0290] In some embodiments, if additional time-domain related parameters are required, one or two more bits can be added to the new field to indicate time-domain probe behavior, such as repetition, skipping, or splitting, across the allocated multiple OFDM symbols (if applicable). The A-SRS time-domain resource allocation field can indicate not only the trigger offset but also the duration of the SRS transmission based on the number of OFDM symbols, as well as other time-domain behavior-related parameters, such as repetition, whether discontinuous symbols are allowed, etc. For example, if the indicated A-SRS symbol length is greater than the A-SRS symbol length configured by the RRC, the A-SRS can be indicated to repetite, skip, or split in the time domain to fill the indicated symbol. One motivation for splitting the SRS into multiple symbols is to pre-schedule data transmission or probe data transmission with reduced SRS PAPR, as described below. Another motivation might be to reduce the SRS bandwidth per transmission, since UE power is typically limited, and therefore the bandwidth for SRS transmission is limited. The UE may not be aware of the probe intent or other intents determined by the network. Therefore, the impact of necessary standards may be to specify how the UE transmits SRS across multiple symbols.

[0291] If the same DCI is to trigger n individual probes on n A-SRS resource sets, then n such TDRA fields can be included. However, to avoid significant redesign of existing DCIs, at least an upper limit should be imposed on n for UE-specific DCIs. For example, UE-specific DCIs should only allow n=1, 2, or 3. If a larger n is required, GC DCIs are more suitable than using UE-specific DCIs. The n individual probes can be on one or more time slots, on one or more carriers, etc.

[0292] According to some embodiments, the following DCI enhancements may be considered.

[0293] - Added A-SRS time domain resource allocation field

[0294] Please see above for a detailed discussion. This may apply to UE-specific DCI and / or GC DCI.

[0295] - Allows for dynamic frequency domain allocation, port allocation, and beamforming, reusing existing DCI fields as much as possible.

[0296] Dynamically indicated A-SRS frequency domain resource allocation can be beneficial in many situations. For example, it can significantly improve the PDSCH spectral efficiency of interference detection in TDD massive MIMO. As another example, A-SRS can be used for CSI acquisition of PUSCH transmissions, so A-SRS can be transmitted only on a set of PRBs that can be scheduled for PUSCH, rather than on pre-configured bandwidths that consume excessive resources and energy or where the gNB cannot acquire the relevant CSI for PUSCH transmissions. Furthermore, dynamically indicated A-SRS frequency domain resource allocation can also be used for SRS coverage / capacity enhancement associated with partial frequency detection. Similarly, dynamically indicated A-SRS port allocation and beamforming are also useful and should be supported.

[0297] To support flexible A-SRS triggering with dynamically indicated frequency domain allocation, we note that existing DCI formats already provide well-designed PUSCH / PDSCH FDRA fields that can be reused or enhanced for A-SRS. Furthermore, if A-SRS is used for CSI acquisition in co-scheduled PUSCH / PDSCH transmissions (rather than for general purposes and not tied to a specific transmission), A-SRS can be transmitted on the same PRB as PUSCH / PDSCH. In this case, the gNB can instruct the UE to reuse the PUSCH / PDSCH FDRA field for A-SRS, which helps avoid high DCI overhead.

[0298] Similarly, to support flexible A-SRS triggering with dynamically indicated port allocation, we can reuse / enhance the existing PUSCH / PDSCH port indication field design, and reuse the PUSCH / PDSCH port indication field if A-SRS is used for CSI acquisition of co-scheduled PUSCH / PDSCH transmissions. To support flexible A-SRS triggering with dynamically indicated beamforming, for non-codebook-based SRS beamforming, we can reuse / enhance the existing design of the CMR / IMR indication in the CSI request field of DCI format 0_1, and for codebook-based SRS beamforming, we can reuse / enhance the existing TPMI field design, and reuse the TPMI field if SRS is used for CSI acquisition of co-scheduled PUSCH transmissions.

[0299] If the same DCI is to be used to trigger n separate probes on n A-SRS resource sets, then n such FDRA fields, n such port indication fields, etc. should be included. However, in order to avoid significant redesign of existing DCIs, at least an upper limit of n should be imposed on UE-specific DCIs. For example, UE-specific DCIs can only allow n=1, 2, [3].

[0300] -Enhanced A-SRS UE-specific UL DCI and DL DCI

[0301] UE-specific UL DCIs (e.g., DCI formats 0-1, 0-2) can be enhanced for A-SRS. For example, we can extend the A-SRS-triggered DCI without co-scheduled PUSCH by adding fields indicating SRS TDRA, FDRA, port, and beamforming to an idle PUSCH field. Furthermore, if SRS is used for CSI acquisition, UL power control information acquisition, UL beamforming, etc., in co-scheduled PUSCH transmissions, we can extend the A-SRS-triggered DCI by reusing PUSCH fields indicating SRS FDRA, port, and beamforming. In this case, the UE first performs A-SRS transmission based on the existing fields indicating FDRA and port, and new fields indicating SRS resource, SRS trigger offset, and CMR / IMR. Then, the UE performs PUSCH transmission based on at least the same FDRA and port indication in the same DCI, and may follow TPC commands sent to the UE in the GC DCI based on power received from A-SRS by the gNB.

[0302] On the other hand, UE-specific DL DCIs (e.g., DCI format 1-1) can be enhanced for A-SRS. If SRS is used for CSI acquisition of co-scheduled PDSCH transmissions, we can extend the DL DCI for A-SRS-triggered A-SRS with co-scheduled PDSCH by reusing the PDSCH fields indicating SRS FDRA, port, and beamforming. In this case, the UE first performs A-SRS transmission based on the existing fields of FDRA, PRB bundle size indication, and port indication, and new fields of SRS resource indication, SRS trigger offset, and CMR / IMR indication. Then, the UE performs PDSCH reception based on at least the same FDRA and port indication in the same DCI.

[0303] -Enhanced A-SRS GC DCI

[0304] GC DCI can be enhanced for A-SRS (e.g., DCI format 2-3 with multiple blocks, each block can be used to trigger one A-SRS transfer).

[0305] The basic design principle for GC DCI used for A-SRS can be that A-SRS transmissions scheduled by GC DCI are likely to occur at approximately the same time, such as within the same time slot or a pair of adjacent time slots. Based on this principle, we can consider adding a group common field to GC DCI to indicate the time slot / symbol location applicable to all A-SRS transmissions triggered by DCI, as well as a UE-specific field for the UE-specific symbol offset (which can span time slots), or a block-specific field for the block-specific symbol offset of the SRS block.

[0306] Furthermore, since A-SRS transmissions may occur in the same time slot, pre-configured SRS transmission resources (e.g., symbol position, PRB, comb / shift, cyclic shift) may not be suitable, and resource conflicts may exist, causing some SRS transmissions to be dropped. To address this issue, GC DCI can indicate SRS multiplexing through UE-specific SRS port resources (symbol, comb / shift, and cyclic shift).

[0307] Figure 17 An example of this is shown. Figure 17Example of SRS resource configuration 1700 for A-SRS transmission. SRS region 1702 can be indicated by an SRS GC DCI. The indication of the SRS region can include the start symbol in a time slot (e.g., time slot n) and optional length (in terms of the number of symbols, e.g., the TDRA field; and the SRS region can span time slot boundaries, e.g., the boundary between time slot n and time slot n+1 shown) and frequency domain allocation. The SRS region start symbol can be indicated as a field common to all SRS blocks. Each SRS block can also be allocated a subset of port resources within SRS region 1702. All SRS port resources within the SRS region indicated in the GC DCI are multiplexed by all SRS port resources within the SRS region. The GC DCI common timing field can indicate only the reference symbol and reference PRB / RBG. All block-specific resource allocations are then relative to the reference symbol and reference PRB / RBG. Port resources in the time domain can include symbol positions, comb and comb shifts, and cyclic shifts. Each SRS block in the GC DCI is allocated a subset of port resources orthogonal to the port resources allocated to other SRS blocks.

[0308] In some embodiments, the following points may be considered regarding time offset and TDRA indication:

[0309] -UL / DL TDRA

[0310] - Non-slot-based (2, 4, 7 symbols for SRS, in UL slots or even DL slots for TDD). SRS trigger time offsets and time-domain resources can use non-slot-based structures.

[0311] -Even preemption (for eMBB / other UEs) can be used to allow for very flexible SRS to insert SRS and optional UL / DL URLLC data.

[0312] - The PDCCH schedules URLLC data (UL / DL) and CSI acquire RS (SRS / CSI-RS) on different symbols, which may all occur in the same time slot.

[0313] In some embodiments, DCI may support the following aspects:

[0314] 1. Support flexible A-SRS triggering enhancements in at least the following UE-specific DCIs:

[0315] - Add an A-SRS time domain resource allocation field.

[0316] - Allows for dynamic frequency domain allocation, port allocation, and beamforming, and reuses existing DCI field designs as much as possible.

[0317] - Enhanced A-SRS with UE-specific UL DCI and DL DCI.

[0318] 2. Support flexible A-SRS triggering enhancements in at least the following groups of common DCIs:

[0319] - Design principle: A-SRS transmissions scheduled by GC DCI are in the same time slot or adjacent time slots.

[0320] • Add a group-common field to the common slot / symbol location for all SRS transmissions.

[0321] • Instructs SRS multiplexing to be performed using UE-specific SRS port resources (symbol, comb / comb shift, and cyclic shift).

[0322] 3. For UL DCI 0_1 and 0_2 that trigger aperiodic SRS without data or CSI, reuse unused fields for SRS parameter indication, including adding new fields to A-SRS and reusing the design of unused fields in A-SRS:

[0323] - Reuse unused PUSCH TDRA fields for A-SRS time-domain resource allocation on one or more OFDM symbols, and reuse PUSCH TDRA field designs as much as possible.

[0324] • A new field has also been added to indicate the probe behavior on multiple assigned OFDM symbols: repeat, skip, or split.

[0325] - Reuse unused PUSCH FDRA fields, port assignment fields, beamforming fields, TPC command fields, etc., for A-SRS, and reuse the same field designs as much as possible.

[0326] - Redesigned the SRS request field to include more bits for indicating SRS resources / resource sets.

[0327] 4. For UL DCI 0_1 and 0_2 with data that trigger aperiodic SRS and DL DCI 1_1 and 1_2 with data:

[0328] - Add an A-SRS TDRA field to one or more OFDM symbols for A-SRS time-domain resource allocation, and reuse the PUSCH / PDSCH TDRA field design as much as possible (up to 4 bits).

[0329] • A new field has also been added to indicate the probe behavior on multiple assigned OFDM symbols: repeat, skip, or split.

[0330] - Add a flag to indicate whether A-SRS also uses the PUSCH / PDSCH field for its parameter indication, including the FDRA field, port assignment field, beamforming field, etc.

[0331] 5. Enhance GC DCI 2_3 to optionally include at least the TDRA field in the SRS trigger block for flexible trigger offsets, and add bits to indicate SRS resources / resource sets.

[0332] If DL coverage for the UE is not an issue, SRS coverage may be limited by the UE's transmission power. The following embodiments are provided to overcome this power limitation.

[0333] One approach is to concentrate power on a narrower bandwidth or fewer subcarriers to improve the UL received SNR. Current probes already support non-wideband transmission (at least 4RBs), but in coverage-constrained situations, narrowband probes can be further segmented into multiple partial probes to cover the bandwidth of a single narrowband probe. This is also useful for utilizing frequency selectivity and reducing interference between SRS from different UEs. Furthermore, this also improves the frequency-selective precoding of the SRS.

[0334] To support partial bandwidth probing, the standard allows for 1-2 PRB probes, PRB skipping, larger combs (i.e., RE skipping), etc.

[0335] However, a potential problem with partial bandwidth probing is that, since each probe transmission is typically associated with an unknown random phase, the gNB may not be able to combine multiple partial bandwidth probing transmissions to obtain wideband CSI. This needs to be addressed.

[0336] One embodiment involves time-domain repetition, including multiple symbols within the same time slot and across multiple time slots. Simple repetition can be supported. Different comb / comb shifts (or interleaving in RE / PRB or repetition with different densities) can also be permitted.

[0337] One embodiment allows TD-OCC in SRS. In CSI-RS, TD-OCC is supported to enhance CSI-RS transmission by utilizing multiple OFDM symbols. This can also be adopted in SRS.

[0338] To increase SRS capacity, the implementation should allow more UEs to probe simultaneously, and allow more probe opportunities / resources and SRS transmissions multiplexed with other signals.

[0339] One approach is to use fewer time / frequency resources per SRS transmission. If each SRS transmission uses fewer subcarriers and / or OFDM symbols, more UEs can be detected, and SRS capacity increases. For example, the SRS comb can be increased to 8 or 12. As another example, PRB skipping or narrower bandwidth for SRS can also be considered, which can improve the aforementioned SRS coverage.

[0340] One embodiment allows non-orthogonal low-correlation sequences. The number of orthogonal sequences in SRS is limited. To allow more SRS transmissions to be multiplexed on overlapping time / frequency resources, non-orthogonal low-correlation sequences can be used. The network can configure / trigger the transmission of non-orthogonal sequences when needed, such as when SRS capacity becomes a limiting factor for operation, but at other times only orthogonal sequences can be used.

[0341] One implementation allows SRS to utilize more time / frequency resources. For example, all 14 symbols in a UL slot can be used for SRS, which is already supported in NR-U. To provide this flexibility, flexible configuration and triggering of SRS need to be standardized. This also incentivizes flexible A-SRS triggering to dynamically / opportunistically utilize unused UL symbols / PRBs, or even DL symbols / PRBs, in TDD. To support the latter, SRS handover gaps (due to RF retuning) similar to SRS carrier-based handovers can be used to harvest some unused DL symbols; that is, the UE switches from DL reception to SRS transmission on one or more OFDM symbols based on network configuration / instructions after the SRS handover gap, and switches back to DL reception after the SRS transmission and another SRS handover gap. Furthermore, concurrent SRS+PUCCH, or even SRS+PUSCH, can be considered to allow for more SRS opportunities.

[0342] Regarding the Type 1 enhancement to time bundling, this could improve SRS coverage. One potential issue is the potential for phase discontinuity. Further analysis suggests that while this may be a problem in general, there are at least a few scenarios where the phase variation between SRS transmissions is sufficiently small, for example, when SRS transmissions are sufficiently close in time, when Doppler is small, or when the UE's transmission chain can maintain phase well between transmissions. In any case, the gNB can determine whether the phase discontinuity is severe, and if not, it can configure the UE to probe within the time bundle, and then the gNB performs joint processing. This may depend on the gNB implementation. As long as the standard provides sufficient support for the configuration and / or indication of SRS transmissions within the time bundle, the rest can be standard-transparent. The current SRS configuration appears generally sufficient, and SRS indication via DCI can be enhanced to trigger time-bundled transmissions.

[0343] In some embodiments, the following points may be considered for time-bundled SRS coverage / capacity enhancements:

[0344] - At least in some cases, the potential phase discontinuity is small enough to support time binding.

[0345] - Provides standard support for time binding through more flexible SRS transmission configuration / instructions, and makes time binding transparent to the UE.

[0346] Regarding the two types of enhancements involving repetition, this is arguably the most direct method to improve SRS coverage and should be supported. The current standard already allows configuring repetition factor values ​​for n1, n2, and n4, and nrofSymbols values ​​for n1, n2, n4, n8, and n12. For enhancement, repetition factor values ​​for n3, n6, n8, etc., can be added, and nrofSymbols values ​​for n3 (supplementing n4 in half-slots), n5 (supplementing n2 in half-slots), n6 (supplementing n1 in half-slots and n8 in the next slot), n10 (supplementing n2 in the next slot), and n14 can be added. An SRS timing can also extend to the next slot. For example, for nrofSymbols of n6, SRS can use the last two symbols in the slot and the four symbols in the next slot. The four symbols in the next slot can be located at the beginning of the slot if the symbols are available SRS time-domain resources, or they can be located at different time-domain positions based on available SRS time-domain resources. The RRC configuration and DCI indication for SRS transmission duplicate / symbol can be enhanced.

[0347] Increased repetition can lead to a reduction in the number of signals / UEs that can be multiplexed simultaneously. This negative impact can be partially compensated for by partial frequency sensing, which will be discussed below. However, this means that standards may need to consider a joint design of time-domain repetition and partial frequency sensing, as frequency-domain resources may become sparser or less abundant as time-domain repetition increases.

[0348] In some embodiments, for SRS coverage / capacity enhancement type 2 (increased redundancy), the following points can be considered:

[0349] - Allows configuration / indication of more repeat factor values ​​and more nrofSymbols values;

[0350] - Allows cross-slot resource mapping;

[0351] - Allows for joint design of partial frequency detection and increased repetition to compensate for the negative impact on SRS capacity.

[0352] The following are some candidate schemes for frequency detection:

[0353] -Scheme 3-1: RB-level partial frequency detection

[0354] -Scheme 3-2: Subcarrier-level partial frequency detection

[0355] -Scheme 3-3: Subband-level partial frequency detection

[0356] - Scheme 3-4: A partial frequency detection scheme supplemented by CSI-RS, wherein the SRS is transmitted in the RB subset of the original SRS frequency resources.

[0357] -Scheme 3-5: Dynamic variation of SRS bandwidth as the size of RB-level subbands scales

[0358] The three enhancements to partial frequency probes primarily include greater flexibility in SRS frequency resources, allowing SRS transmission on a portion of the existing SRS frequency resources. These enhancements are useful for concentrating power on narrower bandwidths or fewer subcarriers to improve UL received SNR. Current probes already support non-wideband transmissions (at least 4 PRBs), but in coverage-constrained situations, narrowband probes can be further segmented into multiple partial probes to cover the bandwidth of a single narrowband probe. This is also useful for utilizing frequency selectivity and reducing interference between SRSs from different UEs. Furthermore, this improves frequency-selective precoding of the SRS. The partial bandwidth granularity can be modified to 1-2 PRBs. However, some limitations can be considered to reduce signaling overhead. If A-SRS is associated with a specific PDSCH / PUSCH transmission, the SRS can have the same granularity as the PDSCH / PUSCH frequency domain resource allocation. For example, for resource allocation type 0 based on resource block groups (RBGs), SRS can also follow the same RBG-based granularity (RBGs are 2 / 4 / 8 / 16 PRBs). For example, when PDSCH / PUSCH is transmitted in multiple discontinuous RBGs, SRS can also be transmitted in multiple discontinuous RBGs. For resource allocation type 1 based on PRBs (contiguous allocation in the frequency domain, i.e., the frequency resources allocated for transmission occupy the frequency resources of consecutive PRBs), the SRS bandwidth can also be as small as one PRB. For example, when PDSCH / PUSCH is transmitted in consecutive PRBs, SRS can also be transmitted in consecutive PRBs.

[0359] Figure 18 An example BiT 1800 is shown, based on A-SRS triggering with partial frequency detection and dynamic indication. Figure 18In this example, the gNB can pre-schedule a subset of PRBs (e.g., PRBs 1802 and 1804) for data transmission in TTI m. To detect interference on the pre-scheduled subset of PRBs used for data, the UE may only need to probe on the subset of PRBs, for example, on PRBs 1802 and 1804 in TTI m+n. Data transmission can then be completed, for example, in TTI m+n+k, where the precoder adjusts according to SRS-based interference detection. Since SRS transmissions are tied to specific data transmissions, flexible A-SRS triggering can be used.

[0360] Partial frequency detection can also be achieved by extending the transmission of a single SRS resource (or resource set) to a multi-hop transmission. For example, an SRS resource on eight PRBs (PRBs 1-8) can be completed in a two-hop transmission, with the first hop on PRBs 1-4 and the second hop on PRBs 5-8. Hops can be configured / indicated based on frequency domain granularity, such as PRBs (i.e., n PRBs per hop) or RBGs (i.e., n RBGs per hop). Different hops can also have different combs and / or different comb shifts. For example, an SRS resource with comb 4 and shift 0 can be divided into two hops, with the first hop having comb 8 and shift 0, and the second hop having comb 8 and shift 4.

[0361] Except for Scheme 3-2, all the above candidate schemes belong to this category, where the granularity of the N consecutive PRBs may differ. For example, for Scheme 3-1, N = 1; for Scheme 3-3, N = 4 or N can be the same as the granularity of the PDSCH / PUSCH frequency domain resource allocation mentioned above (i.e., N = 2, 4, 8, 16); for Scheme 3-4, N = 1, 2, 4, 8, etc.; for Scheme 3-5, N = 2 or 4. Although the motivations of these schemes may differ, their standard impact may be similar, and a unified design can be used to support all of these schemes.

[0362] In summary, schemes 3-1, 3-3, 3-4, and 3-5 belong to category A: partial frequency detection with a granularity of N PRBs can be supported by a unified design, where N = 1, 2, 4, 8, 16, etc.

[0363] If each SRS transmission occupies fewer subcarriers, partial frequency detection can still be achieved, allowing more UEs to detect and increasing SRS capacity. This can also improve SRS coverage while concentrating power. For example, the SRS comb can be increased to 6, 8, or 12. Scheme 3-2 belongs to this category, called Class B: partial frequency detection with a larger comb.

[0364] Please note that in some cases, Class A and Class B may be merged.

[0365] For conventional probes, the SRS occupies a continuous segment of bandwidth, which prevents the peak-to-average power ratio (PAPR) from becoming too high. Depending on the specific proposal / design / implementation, several candidate schemes (e.g., schemes 3-1, 3-2, and 3-3) consider transmitting the SRS over discontinuous segments in the frequency domain, which typically results in a slight increase in PAPR. According to our evaluation, if two or more discontinuous SRS segments are transmitted on the same OFDM symbol, the PAPR may increase by approximately 0.5 dB to 3 dB. Further analysis of the PAPR of discontinuous probes will be described later in this invention.

[0366] There are several possible solutions to the PAPR problem, as described below:

[0367] First, since the increase in PAPR is insignificant and can be estimated in advance by both the gNB and the UE, the gNB can determine some discontinuous SRS transmissions only for certain cell center UEs. This is an implementation-oriented solution that does not require any standards support.

[0368] Secondly, when transmitting K discontinuous SRS segments, the gNB can instruct the UE to autonomously segment the K segments over K OFDM symbols. Therefore, on each OFDM symbol, SRS transmission occurs only on a single continuous PRB. This prevents PAPR increases and further reduces SRS transmission bandwidth, making it suitable for UEs in cell centers and cell edges. This requires some standard support; for example, segmentation could be indicated in the triggering DCI as part of the temporal behavior of SRS over multiple OFDM symbols.

[0369] Discontinuous SRS segments can still be supported without significantly increasing PAPR.

[0370] Figure 19 To illustrate the division of frequency resources 1900 used for SRS transmission. Figure 19In this configuration, the gNB can pre-schedule data transmissions to the UE on frequency resources comprising a first set of contiguous PRB 1902 and a second set of contiguous PRB 1904. These two sets are discontinuous in the frequency domain. The gNB can trigger the UE to probe on the same frequency resources and configure the same frequency resources for the UE to transmit SRS. Upon triggering, the UE can transmit SRS on the configured frequency resources. In one example, the UE can divide the configured frequency resources into two segments (based on these two discontinuous groups), namely segment 1902 and segment 1904, and transmit SRS on two segments 1902 and 1904 on two different OFDM / SC-FDM symbols 1906 and 1908. The UE can divide the frequency resources into more segments, which can be indicated by the gNB or depend on how many discontinuous frequency bands the frequency resources comprise. Within an OFDM / SC-FDM symbol, SRS can be transmitted only on a portion of the frequency resources configured by the RRC or indicated by the DCI, from the gNB to the UE. In one embodiment, the UE can transmit SRS according to the frequency hopping pattern in the two OFDM symbols. In another embodiment, the UE can repeatedly transmit the SRS on a segment of different OFDM symbols. For example, the SRS can be transmitted three times in three different symbols on the same segment 1902. The gNB can instruct whether the SRS transmission should be performed on the segmented frequency resources, whether to hop between OFDM symbols in the frequency band, and / or repeat in OFDM symbols in one or more frequency bands. Upon receiving the SRS, the gNB can adjust the precoder for data transmission on the frequency resources based on the received SRS.

[0371] In some embodiments, standard support can be provided for Class A schemes that may have duplicates / segments.

[0372] All schemes in Class A can be supported by a unified design that can also include possible repetition / segmentation / hopping on multiple OFDM symbols. The DCI that triggers partial frequency probes includes an FDRA field with a bitmap, each bit indicating probes on N consecutive PRBs. Another field in the DCI can be used to indicate whether the probe is repeated on the indicated multiple OFDM symbols, hopping on the indicated multiple OFDM symbols, or segmenting on the indicated multiple OFDM symbols.

[0373] For SRS coverage / capacity enhancement Category 3 (partial frequency detection), the following points can be considered:

[0374] -Supports SRS partial bandwidth granularity based on PDSCH / PUSCH resource allocation granularity;

[0375] -Supports SRS combs 6, 8, and 12;

[0376] - Supports multi-hop SRS resources (an SRS resource is completed by multiple hops of PRB / RBG and / or comb shift).

[0377] In 3GPP Release 17, further enhancements to the MIMO (FeMIMO) detection reference signal include:

[0378] - Identify and specify enhancements for non-periodic SRS triggering to facilitate more flexible triggering and / or reduced DCI overhead / usage;

[0379] - Specify SRS switching for up to 8 antennas (e.g., xTyR, x = {1, 2, 4} and y = {6, 8});

[0380] - Evaluate and, if necessary, specify the following mechanisms to enhance SRS capacity and / or coverage: SRS time bundling, increased SRS repetition, and partial detection across frequencies.

[0381] Motivations for flexible triggering include:

[0382] - The trigger information in DCI is limited (only 1, 2 or 3 bits);

[0383] - Inflexible triggering delay;

[0384] - The important role of SRS in DL full MIMO CSI acquisition, BM, UL frequency diversity and MIMO support;

[0385] -New addition: The important roles of aperiodic SRS (A-SRS) in TDD cooperative MIMO for detecting and mitigating DL interference include:

[0386] - Based on the DL (pre)scheduling results, the UE is routed to Tx SRS so that the gNB can estimate DL interference and then mitigate DL interference through precoder adjustments.

[0387] - This is somewhat similar to interference detection based on DL NZP CSI-RS to achieve better MCS. It is also done after scheduling and before PDSCH, but UL SRS is used to achieve better precoding (and thus better bidirectional training (BiT)).

[0388] - It is also closely related to SRS coverage / capacity enhancement.

[0389] Figure 20A Example single BIT operation flow 2000 is shown. In BIT, precoded SRS is scheduled based on PDSCH, and then based on PDSCH itself. Precoded probing is based on MU pre-scheduling of gNB to collaboratively probe DL interference conditions in UL.

[0390] like Figure 20A As shown, Cov(Y) captures inter-cell / intra-cell interference in the UL. (Cov(Y)) –1 h enables UL interference avoidance. Then, through reciprocity, DL Tx with this precoding enables cooperative DL interference avoidance. The theoretical guidance stems from global optimization.

[0391] Figure 20B and 20C A communication system under prominent interference conditions is shown. Figure 20B The communication system 2030 illustrates a situation where UL SRS transmission by UE 2005 using transmit beamforming results in weak interference at the first BS 2007, while the second BS 2009 sees strong interference. Figure 20C The communication system 2050 illustrates a scenario where beamforming can be used to reduce interference to the UE. The first BS 2057 can use beamforming in the direction of the UE 2055, but the second BS 2059 avoids using beamforming in the direction of the UE 2055 because such transmission could cause high interference at the UE 2055.

[0392] Figure 21A and 21B The example bit performance data are shown for 2100 and 2150.

[0393] Regarding flexible A-SRS triggering for BIT, SRS may include enhancements with dynamic indication parameters associated with the corresponding DL transfer. Enhancements may include:

[0394] - A-SRS triggering with dynamic indication of PRB allocation (e.g., FDRA) and port allocation;

[0395] - A-SRS triggering with dynamic indication of DL channel measurement resources (CMR) and / or interference measurement resources (IMR);

[0396] - A-SRS triggering with flexible trigger delay.

[0397] Motivations related to reducing DCI overhead to enable flexible triggering include:

[0398] - All flexible triggering may result in higher DCI overhead;

[0399] -BiT may also require more A-SRS triggers.

[0400] Example solutions may include:

[0401] - UE-specific DCI with FDRA and port indication for A-SRS (same as PDSCH). However, FDRA may typically require 5-19 bits, and port indication may require 4-6 bits;

[0402] - A group common DCI that may be paired with a group of UEs for MU transmission in a time slot, with FDRA and port indication. However, the SRS trigger offset may not be equal for this group of UEs.

[0403] Based on example embodiments, methods and apparatus are provided for triggering SRS transmissions using all required SRS parameters in the DCI while reducing DCI overhead, along with associated UE assumptions / behaviors / configurations supporting this. Table 2 below shows the current DCI 1-1 format used for scheduling PDSCH in a cell. Table 3 below shows the antenna ports.

[0404] Table 2

[0405]

[0406]

[0407] Table 3

[0408]

[0409] According to the example embodiment, an enhanced DCI 1-1 format is provided. The enhanced DCI 1-1 format supports PDSCH scheduling within a cell, as well as associated SRS probes. Table 4 below provides detailed information about the enhanced DCI 1-1 format.

[0410] Table 4

[0411]

[0412]

[0413] The enhanced DCI 1-1 format includes the following beneficial features:

[0414] SRS probes require the FDRA and antenna port indication fields, but this incurs significant overhead. The Enhanced DCI 1-1 design reuses the existing FDRA and antenna port indication fields in the Associated PDSCH Scheduled DCI and adds a new SRS trigger offset, allowing a single DCI to be used for two operations (e.g., SRS transmission and PDSCH reception).

[0415] -GC DCI can also add a new SRS trigger offset field so that all SRS are transmitted on overlapping resources for BiT purposes.

[0416] Not all new or optional fields need to appear in the enhanced DCI 1-1 format.

[0417] Table 5 below shows further example enhancements to DCI 1-1.

[0418] Table 5

[0419]

[0420] Further enhancements to DCI 2-3 and 0-1 may include: an SRS triggered by a DCI can be linked to another DLDCI, and the SRS can reuse fields from the linked DCI (e.g., FDRA, antenna port).

[0421] Figure 22 The information 2200 exchanged between the gNB and the UE is shown when the gNB configures UL SRS detection and then performs DL transmission based on the UL SRS detection results.

[0422] According to the example implementation, an enhanced DCI 0-1 format is provided. The enhanced DCI 0-1 format supports PUSCH scheduling within a cell, as well as associated SRS probes. Table 6 below provides detailed information about the enhanced DCI 0-1 format. Table 7 below shows example fields in DCI format 0-1 that are reused for A-SRS triggering.

[0423] Table 6

[0424]

[0425]

[0426] Not all new or optional fields need to appear in the enhanced DCI 0-1 format.

[0427] Table 7

[0428]

[0429]

[0430] For all other SRS parameters not indicated in the DCI, RRC / MAC signaling can be used to determine these parameters.

[0431] Table 8 below shows example fields reused for A-SRS triggering in DCI format 1_1.

[0432] Table 8

[0433]

[0434] like Figure 22As shown, A-SRS can also be based on the carrier indication field, bandwidth portion indication field, VRB-PRB mapping field, PRB bundle size field, TPC command for the PUCCH field, or TPC command for the SRS field in DCI. Furthermore, the SRS trigger offset can be indicated in the TDRA field (e.g., reusing a design from PUSCH or PDSCH). CMR and optional IMR can be included for the UE to determine SRS precoding; for example, a design that reuses the CSI request field can be used.

[0435] An example of SRS mapping for resources and ports can be shown below (see reference). Figure 6 ):

[0436] - Assuming DMRS type 1 is used, i.e., 8 ports / RBG / cells for all paired UEs;

[0437] - These 8 ports are associated with 8 SRS port resources selected from n available port resources:

[0438] -For comb 4, n=48,

[0439] - For comb 2, n=16.

[0440] - SRS from neighboring cells should be multiplexed on n SRS port resources.

[0441] Then, indicate to the UE which of the available n SRS port resources, 1, 2, or 4, requires too many bits.

[0442] Figure 23 Example mappings 2305 and 2307, as well as SRS resources and ports, are shown in RGB 2305 and 2307. In one embodiment, a UE group CSI-RS / DMRS design is applied to an SRS design. For example, for each cell, the cell is restricted to a specified number of predefined SRS port resources (e.g., 8, but other values ​​are possible). Then, in the group DCI, the UE's layer / port is indicated from within the specified number (e.g., 8) of predefined SRS port resources. For example, SRS resources are configured for all active UEs in cell 1, with all SRS resources having the same 8 ports. The group DCI indicates which of the 8 ports is used for a specific UE. For example, the rank [1, 2, 4, 1] is indicated for UEs 1, 2, 3, and 4. Layer indexes are not required. Another example is the reuse of DMRS port mappings. As another example, SRS resources can be configured for all RBGs, but the scheduling / group DCI allows different UEs to be scheduled on different RBGs.

[0443] In TS 38.331, the usage of SRS resources is as follows:

[0444] Use ENUMERATED{beam management, codebook, non-codebook, antenna switching}

[0445] In TS 38.214, procedures are specified for SRS resources for different purposes. Some procedures are the same for both "codebook" and "antenna switching," while others are different, as shown below:

[0446] - The UE receives commands based on downlink DCI, group common DCI, or uplink DCI, where the DCI code point can trigger one or more SRS resource sets. For SRS in resource sets whose purpose is set to "codebook" or "antenna switching," the minimum time interval between the last symbol of the PDCCH that triggers aperiodic SRS transmission and the first symbol of the SRS resource is N² + T. switch Otherwise, the minimum time interval between the last symbol of the PDCCH that triggers aperiodic SRS transmission and the first symbol of the SRS resource is N² + T. switch +14. The minimum time interval in OFDM symbols is calculated based on the minimum subcarrier spacing between the PDCCH and the aperiodic SRS.

[0447] - When the UE receives a spatial relation update command for SRS resources, as described in section 6.1.3.26 of [10, TS 38.321], and when the HARQ-ACK corresponding to the PDSCH carrying the update command is transmitted in slot n, the corresponding actions in [10, TS 38.321] and the UE assumptions regarding the update of SRS resource spatial relations shall be applied from slot n. SRS transmission begins in the first time slot thereafter. The update command contains spatial relation assumptions provided by a reference list of reference signal IDs, with each element in the updated SRS resource set having a reference signal ID. Each ID in the list refers to: a reference SS / PBCH block; an NZP CSI-RS resource configured on the serving cell indicated by the resource serving cell ID field in the update command (if present), otherwise the serving cell is the same as the SRS resource set; or an SRS resource configured on the serving cell and uplink bandwidth portion indicated by the resource serving cell ID field and the resource BWP ID field in the update command (if present), otherwise the serving cell and bandwidth portion are the same as the SRS resource set. When the UE configures the higher-layer parameter usage in the SRS-ResourceSet to "Antenna Switching", the UE should not expect to configure different spatial relations for SRS resources in the same SRS resource set.

[0448] - When the UE is configured with the higher-layer parameter usage in the SRS-ResourceSet set to "antenna switching" and a protection period of Y symbols is configured according to clause 6.2.1.2, the UE shall use the same priority rules defined above during the protection period, as if SRS were configured.

[0449] Generally, there are more restrictions on "antenna switching" than on "codebook". In specific operational scenarios, if the same procedure is applicable to different uses, the network can configure one SRS resource for either purpose, but the network can use it for both purposes without standard impact, or the network can configure two SRS resources that are almost identical except for "usage" (which has no standard impact), or the network can configure one SRS resource with two "usage" values ​​(requiring a change to TS 38.331). In general operational scenarios, different uses may require different procedures, thus different SRS resources must be configured. This is determined by the network. Overall, the use cases for this potential enhancement appear to be limited, and potential benefits may include some slight reduction in RRC overhead and avoiding reaching the UE's SRS resource limit 64. Based on the analysis, we tend to stick to the implementation approach rather than the enhancement unless some other strong reasons are identified.

[0450] Therefore, in one embodiment, the system relies on the implementation method to reuse SRS resources for more than one purpose, such as "antenna switching" and "codebook".

[0451] Regarding the support for enhancements related to indicating Tx / Rx antenna subsets during SRS antenna switching, we point out that some CSI measurement-related issues have not been considered in existing discussions. When the number of UE Tx / Rx antennas changes more dynamically, MIMO channel properties also change more dynamically and abruptly. Therefore, UL / DL CSI will change. Existing RI / PMI / CQI, etc., need to support rapid adaptation, such as time-domain-constrained CSI measurements (single CSI-RS or multiple CSI-RS, but without averaging / filtering outside the time window). That is, in the time slot where the UE antenna configuration changes, all CSI measurements need to be reset, and new measurements must be performed without averaging / filtering any measurements from before the time slot.

[0452] If the network wishes to dynamically switch between two or more UE antenna configurations, the network needs to configure multiple sets of CSI measurements / reporting, and averaging over CSI measurement resources is not allowed. If n different UE antenna configurations are configured, each of the n antenna configurations is configured with at least one set of CSI measurement and reporting configurations that are separate / independent from the other UE antenna configurations.

[0453] For more detailed information on discontinuous probe PAPR, please see below. Several evaluations were performed on the discontinuous (frequency) probe segments to demonstrate the extent of PAPR increase. The evaluation considered the following factors:

[0454] - To describe the SRS mode, we use a bitmap of PRBs, where a PRB is marked as 1 to indicate that there is a probe on that PRB, and marked as 0 to indicate that there is no probe on that PRB. For example, [0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1] is used for 16 PRBs in a portion of the bandwidth, transmitting 4 non-contiguous segments, where each segment contains 2 consecutive PRBs for probes and 2 PRBs not used for probes. See [link to example]. Figure 24A .

[0455] - On each PRB, assuming comb 4, that is, each PRB uses 3 subcarriers.

[0456] When probing across multiple discontinuous segments, different sequences can be used on different segments, or the same sequence can be used. Both were evaluated.

[0457] We considered the following factors during our evaluation:

[0458] 1. Scenario 1: Periodic segments with the pattern [0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1…]. Figure 24A An example of this pattern is shown. Figure 24A Example 2410 shows discontinuous probes on 16 PRBs, represented as [0 0 1 10 0 1 1 0 0 1 1 0 0 1 1]. In this mode, we consider:

[0459] 1) Case 1: 8 PRBs ([0 0 1 1 0 0 1 1]; identical sequence);

[0460] 2) Case 2: 16 PRBs ([0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1]; sequences may be the same or different; see Figure 24A );

[0461] 3) Case 3: 32 PRBs ([0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 01 1 0 0 1 1], with the same or different sequences).

[0462] 2. Scenario 2: Periodic segments with the pattern [0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1…]. Figure 24BAn example of this pattern is shown. Figure 24B Example 2430 shows discontinuous probes on 16 PRBs, represented as [0 0 0 10 0 0 1 0 0 0 1 0 0 0 1]. In this mode, we consider:

[0463] 1) Case 1: 8 PRBs ([0 0 0 1 0 0 0 1]; identical sequence);

[0464] 2) Case 2: 16 PRBs ([0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1]; sequences may be the same or different; see Figure 24B );

[0465] 3) Case 3: 32 PRBs ([0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1], with the same or different sequences).

[0466] 3. Scenario 3: Periodic segments with the pattern [0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1…]. Figure 24C An example of this pattern is shown. Figure 24C Example 2450 shows discontinuous probes on 16 PRBs, represented as [0 1 0 10 1 0 1 0 1 0 1 0 1 0 1 0 1]. In this mode, we consider:

[0467] 1) Case 1: 8 PRBs ([0 1 0 1 0 1 0 1]; identical sequence);

[0468] 2) Case 2: 16 PRBs ([0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1]; sequences may be the same or different; see Figure 24C );

[0469] 3) Case 3: 32 PRBs ([0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1], with the same or different sequences).

[0470] 4. Scenario 4: A non-periodic two-segment pattern, in the form of [000011111111000000001111…], with the segments having random positions. Figure 24D An example of this pattern is shown. Figure 24DExample 2470 shows discontinuous detection on the PRB, represented as [000011111111000000001111111111111110000]. For this scenario, we consider the cases shown in Table 9 below.

[0471] Table 9

[0472]

[0473] 5. Scenario 5: A non-periodic 3-segment pattern in the form of [0000111100001111000000001111…], with the segments having random positions.

[0474] For this scenario, we consider the situation shown in Table 10 below.

[0475] Table 10

[0476]

[0477] The evaluation results for scenarios 1-3 are shown in Table 11 below.

[0478] Table 11

[0479]

[0480] As shown in Table 11 above, for scenarios 1-3, the PAPR increment is approximately in the range of 0.8 dB to 4.3 dB, and using the same sequence is better than using different sequences. When focusing on testing with the same sequence, the PAPR increment is in the range of 0.8 dB to 2.9 dB.

[0481] Figure 25A This is a graph 2500 showing the complementary cumulative distribution function (CCDF) of PAPR for discontinuous detection cases 1–4 in scenario 4, where the sequences are identical or discontinuous. From Figure 25A It can be seen that for scenario 4, the PAPR increment is roughly in the range of 0.5 dB to 1.5 dB, and using the same sequence may be better or worse than using a different sequence.

[0482] Figure 25B Figure 2550 shows the CCDF of PAPR for discontinuous detection scenarios 1–3 in scenario 5, where the sequences are the same or different. We can see that for scenario 5, the PAPR increment is also roughly in the range of 0.5 dB to 1.5 dB, and using the same sequence is better than using different sequences in the tested scenarios.

[0483] Evaluations show that, in most cases, for discontinuous probes, even if the probe PRB is not continuous, the UE still wants to use the same sequence to transmit SRS. For example, if a sequence is [s1 s2 s3 s4 s5 s6 s7 s8 s9 s 10 s 11 s 12 …], then it can be transmitted as [s1 s2 s3 gap s4 s5 s6 s7 s8 s9 gap s] 10 s 11 s 12 … ], where the gaps are unprobeged PRBs, meaning that elements in the sequence are not skipped on unprobeged PRBs; they are simply transmitted between different PRBs. Alternatively, it can be transmitted as [s1 s2 s3 gaps s7 s8 s9 gaps s 10 s 11 s 12 …], where the gaps are unprobegated PRBs. That is, some elements in the sequence are skipped on unprobegated PRBs. The network can configure / instruct the UE which transmission mode it intends to use. Furthermore, in a few cases, using different sequences on discontinuous segments results in a lower PAPR than using the same sequence. In these cases, the network can configure / instruct the UE which sequence to use via the sequence index. When the SRS is contiguous in the frequency domain, the UE can generate a first pseudo-random sequence for the SRS based on configured parameters (e.g., a first total sequence length of the SRS based on the total number of PRBs allocated to the SRS). However, on a first contiguous segment of frequency resources, the UE can generate a second pseudo-random sequence for the SRS, for example, the second sequence length of the SRS is determined by the number of PRBs in the first contiguous segment, and the second sequence is generated with the second sequence length as a parameter. In some embodiments, in an A-CSI that triggers DCI, the DCI indicates the SRS on discontinuous PRBs, and the SRS will be transmitted on the same OFDM symbol. The gNB can also transmit one or more sequence indices of the SRS to the UE, along with the length for each sequence. For example, two sequences can be specified. For the first sequence, 12 elements will be used (e.g., one subband configured according to SRS), and for the second sequence, 24 elements will be used (e.g., two subbands configured according to SRS). The UE then transmits the SRS accordingly.

[0484] Figure 26This is a flowchart of embodiment 2600 of the wireless communication method. Method 2600 can instruct the UE to perform operations. The UE can receive downlink control information (DCI) from the access node (AN) that triggers the transmission of an SRS resource set, wherein the DCI includes information indicating a first time-domain resource among the available time-domain resources for transmitting the SRS resource set (step 2602). The UE can determine the available time-domain resources for transmitting the SRS resource set based on the first timeslot of the received DCI (step 2604). The UE can determine the position of the first time-domain resource among the available time-domain resources based on the information in the DCI (step 2606), and transmit the SRS to the AN based on the position of the first time-domain resource (step 2608).

[0485] Figure 27 This is a flowchart of another wireless communication method embodiment 2700. Method 2700 may instruct a UE to perform operations. The UE may receive control information for transmitting one or more sounding reference signals (SRS), wherein the control information includes information indicating frequency resources in a carrier for transmitting one or more SRSs (step 2702). The UE may determine, based on the control information, to divide the frequency resources into multiple segments, each segment including one or more contiguous physical resource blocks (PRBs) (step 2704). The UE may, based on the control information, transmit a first SRS of one or more SRSs in a first orthogonal frequency division multiplexing (OFDM) symbol on a first segment of the multiple segments, rather than a second segment of the multiple segments (step 2706).

[0486] Figure 28This is a flowchart of another wireless communication method embodiment 2800. Method 2800 may instruct a base station to perform an operation, such as an access node (AN). The AN may transmit downlink control information (DCI) to user equipment (UE) to trigger SRS transmission of a sounding reference signal (SRS) resource set, wherein the DCI includes information indicating the location of a first time-domain resource in the available time-domain resources used for transmitting the SRS resource set (step 2802). The available time-domain resources for transmitting the SRS resource set may be based on a first timeslot for transmitting the DCI. The AN may receive the SRS from the UE based on the location of the first time-domain resource (step 2804).

[0487] Figure 29 This is a flowchart of another wireless communication method embodiment 2900. Method 2900 may instruct a base station to perform operations, such as those performed by an access node (AN). The AN may transmit control information to the user equipment (UE) for transmitting one or more sounding reference signals (SRS), wherein the control information includes information indicating frequency resources in a carrier for transmitting the SRS (step 2902). Then, in response to transmitting the control information, the AN may receive a first SRS from the UE in a first orthogonal frequency division multiplexing (OFDM) symbol on a first segment of a plurality of segments divided by frequency resources, instead of receiving the first SRS on a second segment of the plurality of segments (step 2904). Each segment includes a plurality of consecutive physical resource blocks (PRBs).

[0488] The advantage of this embodiment is that control information, such as SRS transmission bandwidth, SRS transmission port, and SRS resource set including SRS transmission comb and cyclic shift, is dynamically transmitted to the pre-scheduled (or scheduled) UE after being configured by higher-layer signaling. The higher-layer signaling is, for example, radio resource control (RRC) or media access control (MAC) control element (CE) signaling.

[0489] Another advantage of this embodiment is that the dynamic signaling of control information does not significantly increase communication overhead, thereby minimizing the impact on the overall performance of the communication system.

[0490] In yet another advantage, embodiments of this disclosure associate SRS configuration parameters (SRS transmission bandwidth and / or port) with physical downlink shared control channel (PDSCH) parameters (bandwidth and / or port) and / or CSI-RS parameters (bandwidth and / or port).

[0491] Figure 30 An example communication system 3000 is illustrated. Generally, system 3000 enables multiple wireless or wired users to transmit and receive data and other content. System 3000 can implement one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), or non-orthogonal multiple access (NOMA).

[0492] In this example, the communication system 3000 includes electronic devices (EDs) 3010a-3010c, radio access networks (RANs) 3020a-3020b, a core network 3030, a public switched telephone network (PSTN) 3040, the Internet 3050, and other networks 3060. Although Figure 30 A certain number of these components or elements are shown, but the system 3000 may include any number of these components or elements.

[0493] ED 3010a-3010c are configured to operate or communicate within System 3000. For example, ED 3010a-3010c are used for transmission or reception via wireless or wired communication channels. Each of ED 3010a to 3010c represents any suitable end-user equipment and may include (or be referred to as) devices such as: user equipment (UE), wireless transmit or receive unit (WTRU), mobile station, fixed or mobile subscriber unit, cellular phone, personal digital assistant (PDA), smartphone, laptop computer, computer, touchpad, wireless sensor, or consumer electronic device.

[0494] RAN 3020a-3020b here includes base stations 3070a-3070b. Each base station 3070a-3070b is configured to radioly intersect with one or more ED 3010a-3010c to allow access to the core network 3030, PSTN 3040, Internet 3050, or other networks 3060. For example, base stations 3070a-3070b may include (or may be) one or more of a number of well-known devices, such as a base transceiver station (BTS), Node-B (NodeB), evolved NodeB (eNodeB), next-generation (NG) NodeB (gNB), home NodeB, home eNodeB, site controller, access point (AP), or wireless router. ED 3010a-3010c is configured to interface and communicate with the Internet 3050 and can access the core network 3030, PSTN 3040 or other networks 3060.

[0495] exist Figure 30 In the illustrated embodiment, base station 3070a forms part of RAN 3020a, which may include other base stations, components, or devices. Similarly, base station 3070b forms part of RAN 3020b, which may include other base stations, components, or devices. Each of base stations 3070a-3070 is used to transmit or receive radio signals within a specific geographic area (sometimes referred to as a "cell"). In some embodiments, multiple-input multiple-output (MIMO) technology may be used, with each cell having multiple transceivers.

[0496] Base stations 3070a-3070b communicate with one or more EDs 3010a-3010c via one or more air interfaces 3090 using a wireless communication link. Air interface 3090 can use any suitable wireless access technology.

[0497] It is conceivable that System 3000 can use multi-channel access capabilities, including the schemes described above. In specific embodiments, the base station and ED implement 5G New Radio (NR), LTE, LTE-A, or LTE-B. Of course, other multiple access schemes and radio protocols can also be used.

[0498] RANs 3020a-3020b communicate with the core network 3030 to provide voice, data, application, Voice over Internet Protocol (VoIP), or other services to EDs 3010a-3010c. It is understood that RANs 3020a-3020b or the core network 3030 can communicate directly or indirectly with one or more other RANs (not shown). The core network 3030 can also act as a gateway to other networks (e.g., PSTN 3040, Internet 3050, and other networks 3060). Furthermore, some or all of EDs 3010a-3010c can communicate with different wireless networks via different wireless links using different wireless technologies or protocols. EDs can communicate with service providers or switches (not shown) and with the Internet 3050 via wired communication channels, rather than wirelessly (or as a supplement to wireless communication).

[0499] Although Figure 30 An example of a communication system is shown, but it is possible to... Figure 30 Various modifications can be made. For example, in any suitable configuration, the communication system 3000 can include any number of EDs, base stations, networks, or other components.

[0500] Figure 31A and Figure 31B Example devices are shown that can implement the method and teachings according to the present invention. In particular, Figure 31A Example ED 3110 is shown. Figure 31B Example base station 3170 is shown. These components can be used in system 3000 or any other suitable system.

[0501] like Figure 31AAs shown, ED 3110 includes at least one processing unit 3100. The processing unit 3100 implements various processing operations of ED 3110. For example, the processing unit 3100 can perform signal encoding, data processing, power control, input / output processing, or any other function that enables ED 3110 to operate in system 3000. The processing unit 3100 also supports the methods and teachings described in detail above. Each processing unit 3100 includes any suitable processing or computing device for performing one or more operations. Each processing unit 3100 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit, etc.

[0502] ED 3110 also includes at least one transceiver 3102. Transceiver 3102 is used to modulate data or other content for transmission via at least one antenna or Network Interface Controller (NIC) 3104. Transceiver 3102 is also configured to demodulate data or other content received via at least one antenna 3104. At least one antenna 3104 is configured to transmit or receive wireless signals 3190. Each transceiver 3102 includes any suitable structure for generating signals for wireless or wired transmission or processing signals received wirelessly or wiredly. Each antenna 3104 includes any suitable structure for transmitting or receiving wireless or wired signals. One or more transceivers 3102 may be used in ED 3110, and one or more antennas 3104 may be used in ED 3110. Although transceiver 3102 is shown as a single functional unit, it can also be implemented using at least one transmitter and at least one separate receiver.

[0503] ED 3110 also includes one or more input / output devices 3106 or interfaces (e.g., a wired interface to the Internet 3050). Input / output devices 3106 facilitate interaction with users or other devices on the network (network communication). Each input / output device 3106 includes any suitable structure for providing or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touchscreen, including network interface communication.

[0504] In addition, ED 3110 includes at least one memory 3108. Memory 3108 stores instructions and data used, generated, or collected by ED 3110. For example, memory 3108 may store software or firmware instructions executed by processing unit 3100, as well as data used to reduce or eliminate interference in incoming signals. Each memory 3108 includes any suitable volatile or non-volatile storage and retrieval device. Any suitable type of memory can be used, such as random access memory (RAM), read-only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, secure digital (SD) card, etc.

[0505] like Figure 31B As shown, base station 3170 includes at least one processing unit 3150, at least one transceiver 3152 (including transmitter and receiver functions), one or more antennas 3156, at least one memory 3158, and one or more input / output devices or interfaces 3166. A scheduler, as understood by those skilled in the art, is coupled to processing unit 3150. The scheduler may be included within base station 3170 or may operate separately from base station 3170. Processing unit 3150 implements various processing operations of base station 3170, such as signal encoding, data processing, power control, input / output processing, or any other functions. Processing unit 3150 may also support the methods and teachings described in detail above. Each processing unit 3150 includes any suitable processing or computing device configured to perform one or more operations. Each processing unit 3150 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit, etc.

[0506] Each transceiver 3152 includes any suitable structure for generating signals for wireless or wired transmission with one or more EDs or other devices. Each transceiver 3152 also includes any suitable structure for processing signals received wirelessly or wiredly from one or more EDs or other devices. Although a transmitter and receiver are shown combined as transceiver 3152, the transmitter and receiver can be separate components. Each antenna 3156 includes any suitable structure for transmitting or receiving wireless or wired signals 3190. Although a common antenna 3156 coupled to transceiver 3152 is shown here, one or more antennas 3156 can be coupled to transceiver 3152, allowing individual antennas 3156 to be coupled to transmitters and receivers (if configured as separate components). Each memory 3158 includes any suitable volatile or non-volatile storage and retrieval device. Each input / output device 3166 facilitates interaction with users or other devices in the network (network communication). Each input / output device 3166 includes any suitable structure for providing information to or receiving / providing information from users, including network interface communication.

[0507] Figure 32 This is a block diagram of a computing system 3200 that can be used to implement the devices and methods disclosed herein. For example, the computing system can be any entity in a UE, access network (AN), mobility management (MM), session management (SM), user plane gateway (UPGW), or access stratum (AS). A specific device may use all of the components shown or only a subset of these components, and the degree of integration may vary between devices. Furthermore, the device may contain multiple instances of components, such as multiple processing units, processors, memories, transmitters, receivers, etc. The computing system 3200 includes a processing unit 3202. The processing unit includes a central processing unit (CPU) 3214, memory 3208, and may also include a mass storage device 3204, a video adapter 3210, and an I / O interface 3212, all of which are connected to a bus 3220.

[0508] Bus 3220 can be one or more of several bus architectures of any type, including a memory bus or memory controller, a peripheral bus, or a video bus. CPU 3214 can include any type of electronic data processor. Memory 3208 can include any type of non-transitory system memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), or combinations thereof. In an embodiment, memory 3208 can include ROM used at power-on and DRAM storing programs and data used during program execution.

[0509] Mass storage device 3204 may include any type of non-transitory storage device for storing data, programs, and other information and making such data, programs, and other information accessible via bus 3220. Mass storage device 3204 may include one or more of solid-state drives, hard disk drives, disk drives, or optical disk drives.

[0510] Video adapter 3210 and I / O interface 3212 provide interfaces for coupling external input and output devices to processing unit 3202. As shown, examples of input and output devices include a display 3218 coupled to video adapter 3210 and a mouse, keyboard, or printer 3216 coupled to I / O interface 3212. Other devices may be coupled to processing unit 3202, and more or fewer interface cards may be used. For example, a serial interface such as Universal Serial Bus (USB) (not shown) may be used to provide interfaces for external devices.

[0511] The processing unit 3202 also includes one or more network interfaces 3206, which may include a wired link (e.g., an Ethernet cable) or a wireless link to an access node or a different network. The network interface 3206 enables the processing unit 3202 to communicate with remote units over a network. For example, the network interface 3206 may provide wireless communication via one or more transmitters / transmit antennas and one or more receivers / receive antennas. In one embodiment, the processing unit 3202 is coupled to a local area network 3222 or a wide area network for data processing and communication with remote devices (e.g., other processing units, the Internet, or remote storage facilities).

[0512] It should be understood that one or more steps in the methods of the embodiments provided herein can be performed by corresponding units or modules. For example, a signal can be transmitted by a transmitting unit or transmitting module. A signal can be received by a receiving unit or receiving module. A signal can be processed by a processing unit or processing module. Other steps can be performed by an indicating unit or module, a determining unit or module, a configuring unit or module, a frequency division unit or module, and / or a scheduling unit or module. The corresponding units / modules can be hardware, software, or a combination thereof. For example, one or more of these units or modules can be integrated circuits, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

[0513] Although the present disclosure and its advantages have been described in detail, it should be understood that various modifications, substitutions and alterations may be made herein without departing from the scope of the disclosure as defined by the appended claims.

Claims

1. A communication method, characterized in that, The method includes: Receive control information for the transmission of one or more sounding reference signals (SRS), the control information including information indicating frequency resources in the carrier for the transmission of the one or more SRS; Based on the control information, the frequency resources are divided into multiple segments, each segment comprising multiple consecutive Physical Resource Blocks (PRBs); and According to the control information, the first SRS of the one or more SRSs is transmitted in a first orthogonal frequency division multiplexing (OFDM) symbol on the first segment of the plurality of segments, but the first SRS is not transmitted in OFDM symbol on the second segment of the plurality of segments.

2. The method according to claim 1, characterized in that, The transmission includes: The SRS is transmitted on the multiple segments using different OFDM symbols according to the control information.

3. The method according to claim 1, characterized in that, The transmission includes: The second SRS is transmitted on the second segment using the second OFDM symbol according to the control information.

4. The method according to claim 3, characterized in that, The first SRS on the first segment and the second SRS on the second segment are transmitted according to the frequency hopping mode.

5. The method according to claim 4, characterized in that, The control information includes instructions to transmit the SRS according to the frequency hopping mode.

6. The method according to any one of claims 1-5, characterized in that, The control information is downlink control information (DCI) or radio resource control (RRC) configuration information.

7. The method according to any one of claims 1-6, characterized in that, The control information includes instructions to divide the frequency resources into the plurality of segments for the transmission of information for the SRS.

8. The method according to claim 7, characterized in that, The control information includes information indicating the number of the plurality of segments.

9. The method according to any one of claims 1-6, characterized in that, Determining to divide the frequency resources into the multiple segments includes: The frequency resource is divided into the multiple segments when the multiple segments are not continuous with each other.

10. The method according to any one of claims 1-9, characterized in that, Transmitting the first SRS includes: The first SRS is repeatedly transmitted on the first segment of the plurality of segments using multiple OFDM symbols.

11. The method according to claim 10, characterized in that, The control information includes information instructing the repeated transmission of the first SRS.

12. The method according to any one of claims 1-11, characterized in that, Also includes: The Physical Downlink Shared Channel (PDSCH) is received on the frequency resources of the carrier.

13. The method according to any one of claims 1-12, characterized in that, The control information includes information indicating the index of a first time-domain resource among the available time-domain resources for transmitting the SRS resource set; and The method further includes: The available time-domain resources for transmitting the SRS resource set are determined based on the time slot of the received control information; and The position of the first time-domain resource in the available time-domain resources is determined based on the index of the first time-domain resource in the available time-domain resources, wherein the first time-domain resource includes the first OFDM symbol.

14. A communication method, characterized in that, The method includes: Control information for transmitting one or more Sounding Reference Signals (SRSs) is transmitted, the control information including information indicating frequency resources in the carrier for the transmission of the SRS; and In response to transmitting the control information, the first SRS of one or more SRSs is received in a first orthogonal frequency division multiplexing (OFDM) symbol on a first segment of a plurality of segments of the frequency resource segmentation, but not on a second segment of the plurality of segments, each segment comprising a plurality of consecutive physical resource blocks (PRBs).

15. The method according to claim 14, characterized in that, The receiving includes: The SRS is received on the multiple segments using different OFDM symbols.

16. The method according to claim 14, characterized in that, The receiving includes: The second SRS is received in the second OFDM symbol on the second segment.

17. The method according to claim 16, characterized in that, The first SRS on the first segment and the second SRS on the second segment are received according to the frequency hopping mode.

18. The method according to claim 17, characterized in that, The control information includes instructions to transmit the SRS according to the frequency hopping mode.

19. The method according to any one of claims 14-18, characterized in that, The control information is downlink control information (DCI) or radio resource control (RRC) configuration information.

20. The method according to any one of claims 14-19, characterized in that, The control information includes instructions to divide the frequency resources into the plurality of segments for transmitting the SRS.

21. The method according to claim 20, characterized in that, The control information includes information indicating the number of the plurality of segments.

22. The method according to any one of claims 14-19, characterized in that, The segments are not continuous with each other.

23. The method according to any one of claims 14-22, characterized in that, Receiving the first SRS includes: The first SRS is repeatedly received on the first segment of the plurality of segments using multiple OFDM symbols.

24. The method according to claim 23, characterized in that, The control information includes information instructing the repeated transmission of the first SRS.

25. The method according to any one of claims 14-24, characterized in that, Also includes: Physical downlink shared channel (PDSCH) is transmitted on the frequency resources in the carrier.

26. A communication device, characterized in that, include: Includes non-transitory memory for instructions; as well as One or more processors communicating with the memory, wherein, when the instructions are executed by the one or more processors, the means are caused to perform the method of any one of claims 1 to 13.

27. An apparatus, characterized in that, include: Includes non-transitory memory for instructions; as well as One or more processors communicating with the memory, wherein, when the instructions are executed by the one or more processors, the means are caused to perform the method of any one of claims 14 to 25.

28. A non-transitory computer-readable medium for storing computer instructions, characterized in that, When executed by one or more processors of the device, the computer instructions cause the device to perform the method of any one of claims 1 to 13, or the method of any one of claims 14 to 25.

Images