Efficient SRS resource indication method

Abstract

The invention of the present disclosure is entitled "Efficient SRS Resource Indication Method." A method for identifying reference signal resources to be used in transmissions by a wireless device is disclosed. The method includes: the wireless device receiving signaling configuring a plurality of reference signal resource groups for the wireless device, each group including a plurality of reference signal resources. The wireless device then receives an indication of a selection of reference signal resources to be used in a control channel. Each of the plurality of reference signal resources to be used is selected from a different reference signal resource group among the plurality of reference signal resource groups such that reference signal resources belonging to the same reference signal resource group are not selected for simultaneous use. A reference signal is then transmitted to a network node in a network using the indicated selection of reference signal resources.

Description

Technical Field

[0001] The disclosed subject matter relates generally to telecommunications and, more particularly, to efficient indication of SRS resources in next generation mobile wireless communication systems. Background Art

[0002] The next generation of mobile wireless communication systems (5G or NR) will support a diverse set of use cases and deployment scenarios. The latter includes deployments at both low frequencies (hundreds of MHz) (similar to today's LTE) and very high frequencies (millimetre waves in the tens of GHz). At high frequencies, propagation characteristics make achieving good coverage challenging. One solution to the coverage problem is to employ high-gain beamforming, typically in an analog manner, to achieve a satisfactory link budget. Beamforming will also be used at lower frequencies (typically digital beamforming) and is expected to be similar in nature to the already standardized 3GPP LTE system (4G).

[0003] Furthermore, it is expected that most future NR networks will be deployed for TDD. One benefit of TDD (compared to FDD) is that TDD implements reciprocity-based beamforming, which can be applied at both the TRP (i.e., for DL) and the UE (i.e., for UL). For reciprocity-based DL transmissions, the UE is expected to transmit a sounding reference signal (SRS), which the TRP will use to estimate the channel between the TRP and the UE. The channel estimate will then be used at the TRP to find the optimal precoding weights for the upcoming DL transmission, for example by using eigenbeamforming. In a similar manner, it is expected that CSI-RS will be used as the sounding signal for reciprocity-based UL transmissions. It has been agreed in NR that the TRP may indicate a quasi-co-location (QCL) assumption for previously transmitted DL reference signals (e.g., CSI-RS) that the UE can use when determining UL precoding.

[0004] Codebook-based precoding

[0005] Multi-antenna technology can significantly increase the data rate and reliability of wireless communication systems. Performance is particularly improved if both the transmitter and receiver are equipped with multiple antennas, resulting in a multiple-input, multiple-output (MIMO) communication channel. Such systems and / or related technologies are generally referred to as MIMO.

[0006] NR standards are currently being specified. A core component of NR is support for MIMO antenna deployments and MIMO-related technologies. NR is expected to support uplink MIMO with channel-dependent precoding and at least four layers of spatial multiplexing using at least four antenna ports. This spatial multiplexing mode targets high data rates in favorable channel conditions. Figure 4An illustration of the spatial multiplexing operation for the case where CP-OFDM is used on the uplink is provided in FIG.

[0007] It can be seen that the information carrying the symbol vector s is multiplied by N T ×r precoding matrix W is used to distribute the transmit energy over N T (corresponding to N T The precoder matrix is ​​typically selected from a codebook of possible precoder matrices and is typically indicated by a precoder matrix indicator (PMI), which specifies a unique precoder matrix in the codebook for a given number of symbol streams. Each of the r symbols in s corresponds to a layer, and r is called the transmission rank. This allows spatial multiplexing, as multiple symbols can be transmitted simultaneously on the same time / frequency resource element (TFRE). The number of symbols r is typically adapted to suit the current channel characteristics.

[0008] LTE and NR use OFDM in the downlink, and therefore the received N for a certain TFRE on subcarrier n (or alternatively data TFRE number n) is given by R ×1 vector y n To model:

[0009] y n =H n Ws n +e n

[0010] where e n is the noise / interference vector obtained as a realization of a random process. The precoder implemented by the precoder matrix W can be a wideband precoder that is constant in frequency or frequency selective.

[0011] The precoder matrix is ​​usually chosen so that it is consistent with N R ×N T MIMO channel matrix H n The precoder matrix is ​​chosen to orthogonalize the channel, which means that after appropriate linear equalization at the UE, inter-layer interference is reduced.

[0012] An example method for the UE to select the precoder matrix W may be to select W that maximizes the Frobenius norm of the assumed equivalent channel k :

[0013]

[0014] in:

[0015] is the channel estimate, which may be derived from the CSI-RS as described further below,

[0016] W k is the hypothesized precoder matrix with index k, and

[0017] W k is a hypothetical equivalent channel.

[0018] In closed-loop precoding for the NR uplink, the TRP transmits a TPMI to the UE based on channel measurements in the reverse link (uplink), which the UE should use on its uplink antennas. The gNodeB configures the UE to transmit SRS according to the number of UE antennas it wants the UE to use for uplink transmissions to enable channel measurements. A single precoder can be signaled that should cover a large bandwidth (wideband precoding). It may also be beneficial to match the frequency variation of the channel and instead feed back frequency-selective precoding reports, for example, several precoders and / or several TPMIs, one per subband.

[0019] The UL MIMO transmission state is typically determined using information other than the TPMI, such as the SRS Resource Indicator (SRI) and the Transmission Rank Indicator (TRI). These parameters, along with the Modulation and Coding State (MCS) and the uplink resources on which the PUSCH is to be transmitted, are also determined by channel measurements derived from the SRS transmissions from the UE. The transmission rank, and therefore the number of spatial multiplexing layers, is reflected in the number of columns in the precoder W. To achieve efficient performance, it is important to select a transmission rank that matches the channel characteristics.

[0020] Non-codebook based UL transmission

[0021] In addition to codebook-based UL transmission, it has been agreed that NR will support a non-codebook-based transmission mode, which is applicable when TX / RX reciprocity holds at the UE. As mentioned earlier, in codebook-based mode, the UE typically transmits a non-precoded SRS to sound the uplink channel, and the gNB determines the preferred precoder from the codebook based on the SRS channel estimate and directs the UE to apply that precoder on the PUSCH transmission using the TPMI included in the UL grant.

[0022] However, for non-codebook-based UL transmissions, the UE determines one or more precoder candidates and uses them to precode one or more SRSs in one or more SRS resources. The gNB correspondingly determines one or more preferred SRS resources and directs the UE to use the precoder(s) to precode the one or more preferred SRS resources and to apply to PUSCH transmissions. This guidance may be signaled in the form of one or more SRIs included in the DCI carrying the UL grant, but may alternatively or additionally include TRI signaling.

[0023] In order for a UE to determine UL precoder candidates, it needs to measure DL reference signals such as CSI-RS to obtain a DL channel estimate. Based on this DL channel estimate, and assuming TX / RX reciprocity, the UE can convert the DL channel estimate into a UL channel estimate and use the UL channel estimate to determine a set of UL precoder candidates, for example by performing a singular value decomposition (SVD) of the UL channel estimate or by other established precoder determination methods. Typically, the gNB implicitly or explicitly configures the UE which CSI-RS resources it can use to assist in precoder candidate determination. In some proposals for NR, this is done by indicating that a certain CSI-RS resource is spatially quasi-co-located (e.g., as part of the RRC configuration) with the SRS resource(s) scheduled by the UE for UL sounding.

[0024] SRS transmission settings

[0025] It is necessary to signal from the TRP to the UE how SRS transmission should be performed, such as which SRS resources to use, the number of ports for each SRS resource, etc. One way to solve this problem (in a low-overhead manner) is to use higher-layer signaling (e.g., RRC) to pre-define a set of "SRS transmission settings" and then indicate in the DCI which "SRS transmission setting" the UE should apply. For example, the "SRS transmission setting" may contain information about which SRS resources and which SRS ports the UE should use in the upcoming SRS transmission.

[0026] How to configure and trigger SRS transmission in NR is still under discussion. Figure 24 A textual proposal for 3GPP technical specification 38.331 defining SRS related parameters is given in .

[0027] like Figure 24As shown, the SRS-Config IE is used to configure the transmission of sounding reference signals. This configuration defines a list of SRS resources and a list of SRS resource sets. Each resource set defines a set of SRS resources. The network uses the configured aperiodic SRS resource trigger (which is carried in the physical layer downlink control information 'L1 DCI') to trigger the transmission of the SRS resource set.

[0028] Therefore, the RRC configuration of "SRS transmission settings" is performed using the IE SRS-Config. The IE SRS-Config contains a list of SRS resources (this list constitutes a resource "pool"), where each SRS resource contains information about the physical mapping of the reference signal on the time-frequency grid, time domain information, sequence ID, etc. SRS-Config also contains a list of SRS resource sets, which contains a list of SRS resources and the associated DCI triggering status. Therefore, when a certain DCI status is triggered, it instructs the UE to transmit the SRS resources in the associated set.

[0029] UL beam management

[0030] The concept of UL beam management (i.e. beam management based on UL reference signals) is currently being developed for NR in order to control the beams (or more precisely the effective antenna patterns) of the respective UE panels. It is expected that UL beam management will be performed by having the UE transmit different SRS resources in different UE panel beams, the TRP performing RSRP measurements on these SRS resources and signaling back the SRI(s) corresponding to the SRS resource(s) with the highest RSRP value(s). If a multi-panel UE is scheduled for SRS transmission from multiple beams from each of the multiple panels, the TRP and the UE need to have mutual agreement on which combinations of SRS resources can be transmitted simultaneously from the different panels. Otherwise, the TRP may select SRS resources that cannot be transmitted simultaneously, such as when the SRS resources correspond to different switched analog beams in the same panel. The following comments on the agreement for signaling multiple SRIs from RAN1#90 (below) address this issue, but do not conclude how it should be done. NOTE: The gNB shall only signal the SRI(s) so that the UE can simultaneously perform UL precoded transmissions inferred from the signaled SRI(s). Summary of the Invention

[0031] To address the aforementioned issues with existing methods, a method for identifying reference signal resources to be used in transmissions by a wireless device is disclosed. The method includes: the wireless device or a UE receiving signaling configuring a plurality of reference signal resource groups for the wireless device, each group including a plurality of reference signal resources. The wireless device then receives an indication of a selection of reference signal resources to be used in a control channel (e.g., a PDCCH). Each of the plurality of reference signal resources to be used is selected from a different reference signal resource group among the plurality of reference signal resource groups, such that reference signal resources belonging to the same reference signal resource group are not selected for simultaneous use. A reference signal is then transmitted to a network node in the network using the indicated selection of reference signal resources.

[0032] In some embodiments, the reference signal resource is a sounding reference signal (SRS) resource, and the transmitted reference signal is an SRS. Furthermore, in some embodiments, the reference signal is transmitted for beam management purposes. The wireless device may include multiple antenna panels, wherein each of the multiple reference signal resource groups corresponds to a different antenna panel in the antenna panels.

[0033] In some embodiments, the indication of the number of reference signal resources to use comprises a bit field whose length depends on the maximum number of MIMO layers that the wireless device is configured to transmit and the number of reference signal resources in a corresponding reference signal resource group. For example, the length of the bit field may be sufficient to indicate S combinations of SRS resources, where And L max is the maximum number of MIMO layers that the wireless device is configured to transmit, and N is the number of resources in the first reference signal resource group.

[0034] In another embodiment, a method for identifying multiple SRS resources to be used in a transmission by a wireless device includes: receiving signaling configuring multiple SRS resources for the wireless device; receiving an indication of the SRS resources to be used in a physical layer downlink control channel; and determining, based on the indication, at least first and second SRS resources to be used in the transmission from the multiple SRS resources. In this embodiment, the first and second SRS resources are allowed to be any SRS resources in the multiple SRS resources, except when the first and second SRS resources are the same. The wireless device may then transmit at least one of: an SRS identified by the first and second SRS resources, and first and second MIMO layers mapped to the first and second SRS resources, respectively.

[0035] In some embodiments, determining at least the first and second SRS resources includes identifying the first and second SRS resources from the plurality of SRS resources by first and second indices, respectively. In addition, the first and second indices further indicate an order in which the first and second SRS resources are to be mapped to the first and second MIMO layers. For example, the first and second MIMO layers may be ordered by quality such that the first MIMO layer has a higher quality than the second MIMO layer, and the first MIMO layer is mapped to the lower index of the first and second indices (or alternatively, the first MIMO layer is mapped to the higher index of the first and second indices).

[0036] In some embodiments, the wireless device determines the first and second SRS resources using a table that includes only one entry for each possible ordering of combinations of SRS resources, thereby limiting the total number of selectable SRS resource combinations.

[0037] Also disclosed is a method for configuring and indicating use of a reference signal transmission setting in a wireless device operable in a wireless communication network. The method may be implemented by a network node, such as a base station. The method includes transmitting signaling to configure a plurality of reference signal resource groups for the wireless device, each group including a plurality of reference signal resources (e.g., SRS resources). The method further includes transmitting an indication of a selection of reference signal resources to be used in a control channel, wherein each of the plurality of reference signal resources to be used by the network node is selected from a different reference signal resource group among the plurality of reference signal resource groups such that reference signal resources belonging to the same reference signal resource group are not selected for simultaneous use. The method further includes receiving a reference signal (e.g., SRS) from the indicated selected wireless device using the reference signal resource.

[0038] Also disclosed is a wireless device comprising a processing circuit configured to perform the steps of any one of the above embodiments.

[0039] According to another embodiment, a network node (e.g., a base station) implements the following method: the method includes transmitting signaling to configure multiple SRS resources for a wireless device. The method further includes transmitting an indication of SRS resources to be used in transmission in a physical layer downlink control channel, the SRS resources including at least first and second SRS resources from the multiple SRS resources. The first and second SRS resources are allowed to be any SRS resources from the multiple SRS resources, except when the first and second SRS resources are the same. The method further includes receiving at least one of the following: an SRS identified by the first and second SRS resources, and first and second MIMO layers mapped to the first and second SRS resources, respectively.

[0040] Also disclosed is a wireless device comprising a processing circuit configured to perform the steps of any one of the above embodiments.

[0041] Also disclosed is a network node comprising a processing circuit configured to perform the steps of any one of the above methods implemented in the network node.

[0042] Technical advantages of the above embodiments include reducing the number of possible reference signal resource indicator states and, therefore, reducing signaling overhead due to the fact that a transmission point (e.g., a network node or a base station) cannot simultaneously select reference signal resources belonging to the same reference signal resource group.

[0043] Reduced downlink control channel overhead for reference signal resource indicator signaling can be achieved, for example, in multi-panel UEs performing UL beam management and / or when using non-codebook-based UL MIMO transmission. Some embodiments further allow for flexible mapping of SRS resources to MIMO layers to control the quality of these layers. Other embodiments reduce the flexibility of mapping SRS resources to MIMO layers while using less downlink control channel overhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings illustrate selected embodiments of the disclosed subject matter. In the drawings, like reference numerals represent like features.

[0045] Figure 1 is a diagram illustrating a wireless communication network.

[0046] Figure 2 is a diagram showing a wireless communication device.

[0047] Figure 3 is a diagram illustrating a radio access node.

[0048] Figure 4 It is a functional block diagram of spatial multiplexing operation.

[0049] Figure 5 is a graphical illustration of an example wireless device having two panels and corresponding SRS resource groups.

[0050] Figure 6 It is used for Figure 5 A table for a wireless device is shown, which has an example mapping between different SRI states and corresponding SRI signaling bits.

[0051] Figure 7 is a table with an example set of different SRI group indices and the corresponding binary and decimal representations of the SRI group indices.

[0052] Figure 8is an example set of SRI indication bits indicating four SRS resources in four corresponding SRS resource groups.

[0053] Figure 9 is a flow chart illustrating a method of operating a wireless device.

[0054] Figure 10 is a diagram illustrating an embodiment of a virtual wireless device.

[0055] Figure 11 is a flow chart illustrating a method of operating a network node.

[0056] Figure 12 is a graphical illustration of an embodiment of a virtual network node device.

[0057] Figure 13 is a flow chart illustrating another method of operating a wireless device.

[0058] Figure 14 is a graphical illustration of another embodiment of a virtual wireless device apparatus.

[0059] Figure 15 is a flow chart illustrating another method of operating a network node.

[0060] Figure 16 is a graphical illustration of another embodiment of a virtual network node device.

[0061] Figure 17 is a flow chart illustrating another method of operating a network node.

[0062] Figure 18 is a graphical illustration of another embodiment of a virtual network node device.

[0063] Figure 19 is a graphical illustration of an example virtualization environment in which embodiments of the present invention may operate.

[0064] Figure 20 is a graphical illustration of a telecommunications network connected to a host computer via an intermediary network in accordance with some embodiments.

[0065] Figure 21 is a graphical illustration of a host computer communicating with a user device via a base station over a partially wireless connection in accordance with some embodiments.

[0066] Figure 22 is a flow chart illustrating a method implemented in a communication system including a host computer, a base station, and a user equipment according to some embodiments.

[0067] Figure 23 is a flow chart illustrating another method implemented in a communication system including a host computer, a base station, and a user equipment according to some embodiments.

[0068] Figure 24 A sounding reference signal (SRS) configuration information element is shown for configuring SRS resources in a wireless device.

[0069] Figure 25 Example operations of a digital precoder matrix in a wireless device are shown. DETAILED DESCRIPTION

[0070] The following description presents various embodiments of the disclosed subject matter. These embodiments are presented as teaching examples and should not be interpreted as limiting the scope of the disclosed subject matter. For example, certain details of the described embodiments may be modified, omitted, or expanded without departing from the scope of the described subject matter.

[0071] Radio node: As used herein, a "radio node" is a radio access node or a wireless device.

[0072] Control node: As used herein, a "control node" is a radio access node or wireless device used to manage, control, or configure another node.

[0073] Radio Access Node: As used herein, a "radio access node" is any node in a radio access network of a cellular communication network that is operable to transmit and / or receive signals wirelessly. Some examples of radio access nodes include, but are not limited to, base stations (e.g., enhanced or evolved Node Bs (eNBs) in 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) networks or gNBs in 3GPP NR networks), TRPs in distributed base stations, high-power or macro base stations, low-power base stations (e.g., micro base stations, pico base stations, home eNBs, etc.), and relay nodes.

[0074] Core network node: As used herein, a "core network node" is any type of node in the core network (CN). Some examples of core network nodes include, for example, a mobility management entity (MME), an evolved serving mobile location center (E-SMLC), a packet data network (PDN) gateway (P-GW), a service capability exposure function (SCEF), and the like.

[0075] Wireless device: As used herein, a "wireless device" is any type of device capable of wirelessly transmitting and / or receiving signals to / from another wireless device or to / from a network node in a cellular communication network to gain access to (i.e., be served by) the cellular communication network. Some examples of wireless devices include, but are not limited to, user equipment (UE) in a 3GPP network, machine type communication (MTC) devices, NB-IoT devices, FeMTC devices, etc.

[0076] Network node: As used herein, a "network node" is any node that is part of a Radio Access Network or CN of a cellular communication network / system or a test equipment node.

[0077] Signaling: As used herein, "signaling" includes any of the following: high-layer signaling (e.g., via radio resource control (RRC) or the like), low-layer signaling (e.g., via a physical control channel or a broadcast channel), or a combination thereof. Signaling can be implicit or explicit. Signaling can further be unicast, multicast, or broadcast. Signaling can also be directly to another node or via a third node.

[0078] As discussed in the background section, if a multi-panel UE is scheduled to perform SRS transmissions from multiple beams from each of the multiple panels, the TRP and the UE need to have mutual agreement on which combinations of SRS resources can be transmitted simultaneously from different panels. Embodiments of the present invention facilitate efficiently signaling an indication of the SRS resources to be used.

[0079] According to one embodiment, SRS resource groups are identified, where only one resource in the SRS resource group can be transmitted at a time. This one resource from each SRS resource group can be transmitted simultaneously with each of the other SRS resources selected from other groups. Assuming the number of SRS resource groups and which SRS resources are in a group is known, the TRP can determine which SRS resources it can direct the UE to transmit when signaling multiple SRS resources. An example is given below:

[0080] Assume that the UE has two panels (Panel A and Panel B), where each panel has four simulated beams (A1-A4 and B1-B4), as shown in Figure 5As shown. The UE will start by signaling to the TRP in the UE capabilities that it has two SRS resource groups, where each SRS resource group consists of four SRS resources. The TRP will then configure different SRS resource sets for the UE (using RRC signaling) (as described above). For example, one SRS resource set may consist of eight SRS resources, where SRS resources 1-4 belong to the first SRS resource group and SRS resources 5-8 belong to the second SRS resource group. During the UE TX beam scanning process, the TRP may trigger this SRS resource set (via an indication in the aperiodic SRS transmission request) and the UE will know which SRS resources should be transmitted on the same panel and which SRS resource should be transmitted on different panels. The TRP may then perform measurements on these eight transmitted SRS resources, determine the best SRS resource for each SRS resource group, and signal the corresponding SRI back to the UE. Note that each SRS resource can consist of one or several SRS ports, so this process is applicable to both non-codebook-based UL transmission (single SRS port per SRS resource) and codebook-based UL transmission (one or several SRS ports per SRS resource). However, note that for non-codebook-based UL transmission that allows precoding each SRS resource on multiple antenna ports, in this case (i.e., when there is UL beam management), SRS precoding should not be applied on antenna ports belonging to different panels (because that would break the mutual agreement that a certain SRS resource belongs to only a certain panel).

[0081] In some embodiments, the number of possible SRI states, and therefore the SRI signaling overhead, is reduced by taking advantage of the fact that a TRP cannot simultaneously select SRS resources belonging to the same SRS resource group. This can be accomplished by configuring a mapping between SRI signaling bits and possible SRI states for an SRS resource set containing multiple SRS resource groups via RRC. In such embodiments, an SRS group can be selected from the total set of SRS groups configured for the UE, and an SRS resource can be selected from the selected SRS group.

[0082] In other embodiments, L is selected from all remaining possible SRS resources configured for the UE. max Each of the SRS resources is mapped to the MIMO layers, thereby allowing the SRS resources to be mapped to the MIMO layers in the desired order.

[0083] In other embodiments, combinations of SRS resources are selected according to a single fixed ordering method, thereby using fewer SRI signaling bits, but not allowing arbitrary ordering of SRS resource to MIMO layer mapping.

[0084] Reduced downlink control channel overhead for SRS signaling can be achieved, for example, in multi-panel UEs performing UL beam management and / or when using non-codebook-based UL MIMO transmission. Some embodiments further allow for flexible mapping of SRS resources to MIMO layers to control the quality of these layers. Other embodiments reduce the flexibility of mapping SRS resources to MIMO layers while using less downlink control channel overhead.

[0085] In one example of a "normal" SRS transmission (e.g., SRS transmission for non-codebook / codebook-based UL transmission without UL beam management), SRS signaling from the TRP may indicate to the UE which SRS resources it should use for PUSCH transmission and in what order they should be mapped to the spatially multiplexed ('MIMO') PUSCH layers. This signaling selects any one of the SRS resources to be transmitted on the first MIMO PUSCH layer, such as the one the gNB considers to have the best quality (e.g., SINR, SINR, etc.), and then selects any SRS resources it considers to have the next best quality from the remaining resources to be transmitted to the second MIMO PUSCH layer, and so on, until it has selected the L1 PUSCH layers in order of decreasing quality. max SRS resources. Note that in some embodiments, metrics other than quality may be used to select SRS resources. In this embodiment, the total number of SRI states that need to be signaled to the UE is then: Among them S L =N·(N-1)·...·(N-(L-1)) or equivalently is the number of SRI states for a given number of layers L, N is the number of SRS resources in the triggered SRS resource set, L is the number of SRS resources that can be triggered by SRI, and L max is the maximum number of SRS resources on which a UE can transmit simultaneously (i.e., for a single SRS port, SRS resources L and L max =N=8; L=1 or 2). The total number of possible SRI states is S. T =8+8·7=64. This means that, in this embodiment, 6 bits are required to indicate the selected SRI state to the UE.

[0086] For example, when a single channel coded transport block is mapped across MIMO layers and a single modulation and coding state is used (also known as 'single codeword' MIMO transmission), the order of the SRS resources relative to the corresponding PUSCH MIMO layer may not be important. Therefore, in an embodiment, the SRI signaling from the TRP to the UE is possible SRI states, where is the number of combinations of taking k values ​​from N values ​​at a time, and N, L and L max Same as above. In this embodiment, N=8 and L=1 or 2, so the total number of possible SRI states is This means that 6 bits are still needed to indicate the selected SRI state to the UE. Similarly, if the selection is limited to L=2 SRS resources, the possible number of SRI states is This means that, in this case, 5 bits are needed to indicate the selected SRI state to the UE.

[0087] By considering the constraints on the SRS and / or PUSCH MIMO layer transmission, it is possible to further reduce the SRI overhead. For example, assume that the UE has 2 panels and each panel has four simulated beams, such as Figure 5 as shown. In this case, many possible SRI states will not be allowed, because only one SRS resource can be selected from each SRS resource group. (Note that we use the term 'SRS resource group' rather than 'SRS resource set' here to emphasize the constraint on SRS selection; both are lists of SRS resources configured for the UE, and an SRS resource set constrained in this way is equivalent to an SRS resource group) Therefore, in this case, it is preferable to map between possible SRI states and SRI signaling bits in order to reduce overhead. In this example, L=2 SRS resources are selected: only one of the A1-A4 beams in panel A, and only one of the B1-B4 beams in panel B. Therefore, the total number of SRI states will be 4x4=16, which will require 4 SRI signaling bits (a 20% reduction compared to the above example where 5 bits were required for L=2 selected SRS resources). Figure 6 A table showing the mapping between different SRI states and SRI signaling bits.

[0088] More generally, for an embodiment, the formula for the number of SRI states can be written as in The state is used to select any of the g SRS resource groups in a single fixed order, and M istates (each state is associated with an SRS resource group selection state) for selecting an SRS resource (corresponding to a beam) from each selected SRS resource group, where M i is the number of SRS resources (beams) of the selected SRS resource group with index i (corresponding to the i-th panel), G k is the kth set of indices of the selected SRS resource group (i.e., G k is a set of g elements {1, 2, ..., N g}kth subset), and N g is the total number of SRS groups (panels).

[0089] For simplicity in signaling, a state may be assigned such that the maximum number of resources per resource group, M, in any SRS resource group configured for the UE is always assumed when calculating the SRI. max , and the number of SRI states can then be written as

[0090] The single fixed order may be such that the combination of SRS resource indices selected by the SRI is monotonically increasing, such that the first MIMO layer has the lowest SRS index, the second MIMO layer has the second lowest SRS index, etc. Alternatively, the combination of SRS resource indices selected by the SRI is monotonically decreasing, such that the first MIMO layer has the highest SRS index, the second MIMO layer has the second highest SRS index, and so on.

[0091] In this embodiment, when there are N g = 2 resource groups, each SRS resource group has M i = 4 resources and L max =2, S is required T = 24 SRI states, and thus 5 bits can be used to signal SRI to the UE in this embodiment.

[0092] In some embodiments, the SRI may be encoded as follows:

[0093]

[0094] Where 0≤X l <M l is the identifier of the SRS resource selected from the SRS resource group with index 1, and The number L of selected SRS resource groups and the value of Y( ) may correspond to the selected SRS resource group index in a given row of the table Where L is the number of selected SRS resources. Figure 7 In the table, L is configured max= 4 SRS resource groups. The possible values ​​of L and The corresponding value of . Generally speaking, L is constructed by the following method max Table of given values: First select L max Each possible resource group in the SRS resource groups, then select L max For each possible pair of resource groups in the SRS resource groups, then select L max Each possible combination of 3 resource groups of 1 SRS resource group, and so on. The pairs and combinations are selected so that the indices of the selected resource groups follow a fixed order, such as a monotonically increasing order, and so that each pair or combination appears only once in the table.

[0095] In some embodiments, the number of layers L may be strictly less than the number of SRS resource groups configured for the UE L max In this case, the function constructed as described above and shown in the following example table Can be generated by comparing the L≤L max This can be seen in the table below by observing that for L=1, The value of L is 3 or less, so 2 bits are required to encode, while in the case of L≤4, 4 bits are required. Therefore, in an embodiment, the size of the field used to signal SRI is determined according to the maximum number of MIMO layers that the UE is configured to transmit, the number of SRS resource groups from which SRS resources can be selected, and the number of SRS resources in one or more SRS groups.

[0096] In an alternative embodiment, the SRI is encoded directly into a bit stream, rather than first being encoded into a decimal number and then mapped to a certain number of bits in the DCI. If the number of SRS resources per SRS resource group is a power of 2, i.e., This embodiment is functionally equivalent to the previously discussed embodiment. The binary representation of X is mapped to the most significant bit, then the binary representation of X1 is mapped to the subsequent bits, and then the binary representation of X2 is mapped, and so on, until X is mapped to the most significant bit. L Map to the least significant bit. If L<L max , the bit stream is padded with 0s to fill the field size. Figure 8 An example of such bit mapping is given in , where it is assumed that there are 4 SRS resource groups, each of which includes 4 SRS resources.

[0097] The described embodiments may be implemented in any suitable type of communication system supporting any suitable communication standard and using any suitable components. As an example, some embodiments may be implemented in an LTE network such as Figure 1 is implemented in the LTE network shown).

[0098] refer to Figure 1 , a radio access communication network 100 includes a plurality of wireless communication devices 105 (e.g., conventional UEs, machine type communication [MTC] / machine to machine [M2M] UEs) and a plurality of radio access nodes 110 (e.g., eNodeBs or other base stations). The communication network 100 is organized into a plurality of cells 115, which are connected to a core network 120 via corresponding radio access nodes 110. The radio access nodes 110 are capable of communicating with the wireless communication devices 105, along with any additional elements suitable for supporting communication between the wireless communication devices or between the wireless communication device and another communication device (e.g., a landline phone).

[0099] While wireless communication devices 105 may represent communication devices comprising any suitable combination of hardware and / or software, in certain embodiments, these wireless communication devices may represent devices such as those provided by Figure 2 Similarly, although the radio access nodes shown may represent network nodes comprising any suitable combination of hardware and / or software, in certain embodiments these nodes may represent devices such as those provided by Figure 3 An example radio access node or similar apparatus is shown in greater detail.

[0100] refer to Figure 2 , the wireless communication device 200 includes a processor 205, a memory, a transceiver 215, and an antenna 220. In some embodiments, some or all of the functionality described as being provided by a UE, an MTC or M2M device, and / or any other type of wireless communication device may be executed by the device processor and stored in a memory such as a memory. Figure 2 Alternative embodiments may include instructions on a computer readable medium such as the memory shown. Figure 2 Additional components beyond those shown in the figure may be responsible for providing certain aspects of the functionality of the device, including any functionality described herein.

[0101] refer to Figure 3 , the radio access node 300 includes a node processor 305, a memory 310, a network interface 315, a transceiver 320, and an antenna 325. In some embodiments, some or all of the functionality described as being provided by a base station, gNodeB, eNodeB, and / or any other type of network node may be executed by the node processor 305 and stored in a memory such as Figure 3The illustrated instructions are provided by instructions on a computer readable medium such as the memory 310. Alternative embodiments of the radio access node 300 may include additional components that provide additional functionality, such as the functionality described herein and / or related supporting functionality.

[0102] Figure 9 1 is a flow chart illustrating a method 900 for operating a wireless device (e.g., wireless communication device 105). Method 900 includes step S905, in which signaling is received from a network node in a wireless communication network, the signaling configuring the wireless device to use multiple reference signal resource groups, each group including multiple reference signal resources. The signaling may configure the wireless device to use multiple reference signal resource groups in a temporary sense, i.e., multiple reference signal resource groups to be used as indicated by a message in a subsequently received control channel.

[0103] The method further includes step S910, in which an indication is received from a network node in a control channel (e.g., a physical layer downlink control channel), the indication including an indication of reference signal resources to be used. Each of the reference signal resources to be used may be limited to a different group selected from the plurality of reference signal resource groups, such that reference signal resources belonging to the same reference signal resource group are not selected for simultaneous use. For example, the reference signal resources to be used include first and second reference signal resources selected only from respective first and second reference signal resource groups from the plurality of reference signal resource groups. The method 900 further includes step S915 of transmitting a reference signal to the network node using the first and second reference signal resources.

[0104] In an alternative embodiment, method 900 may further include steps S911, S912, and S913 between S910 and S915, wherein the UE makes various determinations based on the indication received in step S910. For example, in optional step S911, the wireless device determines first and second reference signal resource groups based on the indication, wherein the reference signal resource groups are reference signal resource groups. In optional step S912, the wireless device determines first reference signal resources selected only from the first reference signal resource group based on the indication, and in optional step S913, the wireless device determines second reference signal resources selected only from the second reference signal resource group based on the indication. In addition, in an alternative embodiment, step S915 may include transmitting reference signals identified by the first and second reference signal resources and at least one of the first and second MIMO layers mapped to the first and second reference signal resources, respectively.

[0105] In one embodiment, the reference signal resource is a sounding reference signal (SRS) resource. In one embodiment, the indication of the plurality of reference signal resources to be used comprises a bit field, wherein the length of the bit field depends on the maximum number of MIMO layers that the wireless device is capable of transmitting and the number of reference signal resources in a corresponding reference signal resource group in the reference signal resource group. (When uplink MIMO operation is configured for the wireless device, the wireless device may also be configured to transmit the maximum number of MIMO layers that the wireless device is capable of transmitting.) The length of the bit field is sufficient to indicate S combinations of SRS resources, where:

[0106] as well as

[0107] Among them L max is the maximum number of MIMO layers that the wireless device is configured to transmit, and N is the number of resources in the first reference signal resource group. In another embodiment, the bit field size may be determined based on the maximum number of MIMO layers that the wireless device is configured to transmit, the number of SRS resource groups from which SRS resources may be selected, and the number of SRS resources in the plurality of SRS resource groups.

[0108] In one embodiment, the reference signal is transmitted for beam management purposes.Furthermore, in one embodiment, the wireless device may include a plurality of antenna panels, each of the plurality of reference signal resource groups corresponding to a different one of the antenna panels.

[0109] Figure 10 Is a wireless network (for example, Figure 1 Schematic block diagram of a device 1000 in a wireless network (shown in FIG. 1 ). The device may be used in a wireless device (e.g., Figure 1 The apparatus 1000 is operable to implement the reference Figure 9 The example methods described and possibly any other processes or methods disclosed herein. For example, module S1005 may implement the functionality of step S905; module S1010 may implement the functionality of step S910; optional module S1011 may implement the functionality of optional step S911; optional module S1012 may implement the functionality of optional step S912; optional module S1013 may implement the functionality of optional step S913; and module S1015 may implement the functionality of step S915. It is also understood that Figure 9 The method is not necessarily implemented only by the device 1000. At least some operations of the method may be performed by one or more other entities.

[0110] Figure 111 is a flow chart illustrating a method 1100 for operating a network node. The method 1100 includes step S1105, in which a total number of possible reference signal states is determined, the determination being based on grouping reference signal resources into reference signal resource groups, the grouping being configured such that only one reference signal resource can be selected from each reference signal resource group for use in transmission. The method further includes step S1110, in which a mapping of different combinations of reference signal indicator bits to corresponding reference signal states from the possible reference signal states is determined. The mapping is then signaled to a wireless device in step S1115, and one or more preferred reference signal resources for UL transmission from the wireless device is determined in step S1120. The method further includes step S1125, in which the reference signal indicator bits mapped by the mapping to the SRI states corresponding to the one or more preferred reference signal resources are signaled to the wireless device.

[0111] Figure 12 Shows a wireless network (e.g., Figure 1 Schematic block diagram of a virtual device 1200 in a wireless network as shown. The device can be used in a network node (e.g., Figure 1 The device 1200 is operable to refer to the network node 110 shown in FIG. Figure 11 The example methods described herein, and possibly any other processes or methods disclosed herein. For example, module S1205 may implement the functionality of step S1105; module S1210 may implement the functionality of step S1110; module S1215 may implement the functionality of step S1115; module S1210 may implement the functionality of step S1110; module S1215 may implement the functionality of step S1115; module S1220 may implement the functionality of step S1120; and module S1225 may implement the functionality of step S1125. It is also understood that Figure 11 The method is not necessarily implemented only by the device 1200. At least some operations of the method may be performed by one or more other entities.

[0112] Figure 1313 is a flow chart illustrating another method 1300 for operating a wireless device (e.g., wireless communication device 105). Method 1300 includes step S1305, in which the wireless device receives signaling configuring a plurality of SRS resources for the wireless device. The signaling configuring the plurality of SRS resources for the wireless device may also indicate grouping the plurality of SRS resources into a plurality of SRS resource groups, each group including a plurality of SRS resources, and wherein the first and second SRS resources are selected from the same SRS resource group. The method further includes step S1310, in which the wireless device receives an indication of SRS resources to be used in a physical layer downlink control channel. The method further includes step S1315, in which the wireless device determines, based on the indication, at least first and second SRS resources to be used in transmission from the plurality of SRS resources. For example, based on a predetermined SRS resource selection rule, the indicated and determined first and second SRS resources are allowed to be any SRS resources from the plurality of SRS resources, except where the first and second SRS resources are the same. For example, the wireless device may determine the first and second SRS resources using a predetermined table that includes only one entry for each possible ordering of combinations of SRS resources, thereby limiting the total number of selectable SRS resource combinations.

[0113] Method 1300 further includes step S1320, in which the wireless device transmits an SRS identified by the first and second SRS resources and / or the first and second MIMO layers mapped to the first and second SRS resources, respectively. Determining the first and second SRS resources in step S1315 may include identifying the first and second SRS resources from the plurality of SRS resources by first and second indices, respectively, the first and second indices further indicating the order in which the first and second SRS resources are to be mapped to the first and second MIMO layers. For example, the first and second MIMO layers are sorted by quality such that the first MIMO layer has a higher quality than the second MIMO layer, and the first MIMO layer is mapped to by the lower index of the first and second indices. Alternatively, the first MIMO layer may be mapped to by the higher index of the first and second indices.

[0114] Figure 14 Shows a wireless network (e.g., Figure 1 Schematic block diagram of a virtual device 1200 in a wireless network as shown. The device can be used in a wireless device (e.g., Figure 1 The apparatus 1400 is operable to implement the reference Figure 13The example methods described and possibly any other processes or methods disclosed herein. For example, module S1405 may implement the functionality of step S1305; module S1410 may implement the functionality of step S1310; module S1415 may implement the functionality of step S1315; and module S1420 may implement the functionality of step S1320. It is also understood that Figure 13 The method is not necessarily implemented only by the device 1400. At least some operations of the method may be performed by one or more other entities.

[0115] Figure 15 15 is a flow chart illustrating a method 1500 of operating a network node. The method 1500 includes step S1505, in which the network node transmits signaling to configure a plurality of reference signal resource groups for a wireless device, each group including a plurality of reference signal resources, such as sounding reference signal (SRS) resources. In one embodiment, the wireless device includes a plurality of antenna panels, and each of the plurality of reference signal resource groups corresponds to a different antenna panel in the antenna panels. The network node may learn the number of antenna panels and the number of antennas on each panel, for example, via a capability message transmitted from the wireless device in a control channel.

[0116] Method 1500 further includes step S1510, in which the network node transmits an indication of a selection of reference signal resources to be used in a control channel. The network node selects each of the plurality of reference signal resources to be used from a different reference signal resource group from the plurality of reference signal resource groups according to a predetermined rule, such that reference signal resources belonging to the same reference signal resource group are not selected for simultaneous use. The indication of the plurality of reference signal resources to be used may include a bit field, the length of which depends on the maximum number of MIMO layers that the wireless device is configured to transmit and the number of reference signal resources in a corresponding reference signal resource group from the reference signal resource groups. Furthermore, the bit field may have a length sufficient to indicate S combinations of SRS resources, where:

[0117] as well as

[0118] Among them L max is the maximum number of MIMO layers that the wireless device is configured to transmit, and N is the number of resources in the first reference signal resource group.

[0119] Method 1500 further includes step S1515, in which the network node receives a reference signal (e.g., SRS) from the indicated selected wireless device using reference signal resources. In one embodiment, the reference signal is received as part of a beam management process initiated by the network node or wireless device.

[0120] Figure 16 Show wireless network (for example, Figure 1 Schematic block diagram of a virtual device 1600 in a wireless network as shown. The device can be used in a network node (e.g., Figure 1 The device 1600 is operable to implement the reference Figure 15 The method described herein and possibly any other process or method disclosed herein. For example, module S1605 may implement the functionality of step S1505; module S1610 may implement the functionality of step S1510; and module S1615 may implement the functionality of step S1515. It is also understood that Figure 15 The method is not necessarily implemented only by the device 1600. At least some operations of the method may be performed by one or more other entities.

[0121] Figure 17 17 is a flow chart illustrating a method 1700 for operating a network node. Method 1700 includes step S1705, in which the network node transmits signaling for configuring a plurality of SRS resources for a wireless device. The signaling for configuring the plurality of SRS resources for the wireless device may also indicate that the plurality of SRS resources are grouped into a plurality of SRS resource groups, each group including a plurality of SRS resources, and wherein the first and second SRS resources are selected from the same SRS resource group. The method further includes step S1710, in which the network node transmits an indication of SRS resources to be used in a physical layer downlink control channel. The wireless device may determine, based on the indication, at least a first and a second SRS resource to be used in the transmission from the plurality of SRS resources. For example, based on a predetermined SRS resource selection rule, the indicated and determined first and second SRS resources may be any SRS resource from the plurality of SRS resources, except where the first and second SRS resources are the same. For example, the wireless device may determine the first and second SRS resources using a predetermined table that includes only one entry for each possible ordering of combinations of SRS resources, thereby limiting the total number of selectable SRS resource combinations.

[0122] Method 1700 further includes step S1715, in which the network node receives an SRS identified by a first and a second SRS resource and / or a first and a second MIMO layer mapped to the first and the second SRS resource, respectively. In step S1710, the indication of the first and the second SRS resource may identify the first and the second SRS resource from the plurality of SRS resources by a first and a second index, respectively, and the first and the second index further indicate the order in which the first and the second SRS resources are to be mapped to the first and the second MIMO layers. For example, the first and the second MIMO layers are sorted by quality such that the first MIMO layer has a higher quality than the second MIMO layer, and the first MIMO layer is mapped to by the lower index of the first and the second indexes. Alternatively, the first MIMO layer may be mapped to by the higher index of the first and the second indexes.

[0123] Figure 18 Show wireless network (for example, Figure 1 Schematic block diagram of a virtual device 1800 in a wireless network as shown. The device can be used in a network node (e.g., Figure 1 The device 1800 is operable to implement the reference Figure 17 The example methods described and possibly any other processes or methods disclosed herein. For example, module S1805 may implement the functionality of step S1705; module S1810 may implement the functionality of step S1710; and module S1815 may implement the functionality of step S1715. It is also understood that Figure 18 The method is not necessarily implemented only by the device 1800. At least some operations of the method may be performed by one or more other entities.

[0124] Each virtual device 1000, 1200, 1400, 1600, and 1800 may include: processing circuitry, which may include one or more microprocessors or microcontrollers; and other digital hardware, which may include a digital signal processor (DSP), dedicated digital logic, etc. The processing circuitry may be configured to execute program code stored in a memory, which may include one or more types of memory, such as read-only memory (ROM), random access memory, cache memory, flash memory devices, optical storage devices, etc. In some embodiments, the program code stored in the memory includes program instructions for executing one or more telecommunications and / or data communication protocols and instructions for implementing one or more techniques described herein. In some implementations, the processing circuitry may be used to perform the functionality of any appropriate unit of device 1000 or 1200 to perform corresponding functions according to one or more embodiments of the present disclosure.

[0125] The term "unit" may have a conventional meaning in the field of electronics, electrical devices and / or electronic devices, and may include, for example, electrical and / or electronic circuits, devices, modules, processors, memories, logical solid-state and / or discrete devices, computer programs or instructions for implementing corresponding tasks, processes, calculations, output and / or display functions such as those described herein.

[0126] Operations in a virtualized environment

[0127] Figure 19 is a schematic block diagram illustrating a virtualization environment 1900 in which functionality implemented by some embodiments may be virtualized. In this context, virtualization means creating a virtual version of a device or apparatus, which may include a virtualized hardware platform, storage, and networking resources. As used herein, virtualization may be applied to a node (e.g., a virtualized base station or a virtualized radio access node) or a device (e.g., a UE, a wireless device, or any other type of communication device) or a component thereof, and involves implementing at least a portion of that functionality as one or more virtual components (e.g., via one or more applications, components, functions, virtual machines, or containers executing on one or more physical processing nodes in one or more networks).

[0128] In some embodiments, some or all of the functionality described herein may be implemented as virtual components executed by one or more virtual machines implemented in one or more virtual environments 1900 hosted by one or more hardware nodes 1930. Furthermore, in embodiments where the virtual nodes are not radio access nodes or do not require radio connectivity (e.g., core network nodes), then the network nodes may be fully virtualized.

[0129] These functions may be implemented by one or more applications 1920 (the applications 1920 may alternatively be referred to as software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) operable to implement some of the features, functions, and / or benefits of some embodiments disclosed herein. The applications 1920 are executed in a virtualized environment 1900 that provides hardware 1930 including processing circuitry 1960 and memory 1990. The memory 1990 contains instructions 1995 executable by the processing circuitry 1960, whereby the applications 1920 are operable to provide one or more of the features, benefits, and / or functions disclosed herein.

[0130] The virtualized environment 1900 includes general-purpose or specialized network hardware devices 1930, which include a collection of one or more processors or processing circuits 1960, which may be commercial off-the-shelf (COTS) processors, specialized application-specific integrated circuits (ASICs), or any other type of processing circuitry including digital or analog hardware components or specialized processors. Each hardware device may include memory 1990-1, which may be non-persistent memory for temporarily storing instructions 1995 or software executed by the processing circuits 1960. Each hardware device may include one or more network interface controllers (NICs) 1970 (also known as network interface cards), which include physical network interfaces 1980. Each hardware device may also include non-transitory, persistent, machine-readable storage media 1990-2, which stores software 1995 and / or instructions executable by the processing circuits 1960. The software 1995 may include any type of software, including software for instantiating one or more virtualization layers 1950 (also known as hypervisors), software for executing virtual machines 1940, and software that enables it to perform the functions, features and / or benefits described in connection with some of the embodiments described herein.

[0131] The virtual machine 1940 includes virtual processing, virtual memory, virtual networking or interfaces, and virtual storage devices, and can be run by a corresponding virtualization layer 1950 or hypervisor. Different embodiments of instances of the virtual device 1920 can be implemented on one or more virtual machines 1940, and these implementations can be performed in different ways.

[0132] During operation, processing circuitry 1960 executes software 1995 to instantiate a hypervisor or virtualization layer 1950, which is sometimes referred to as a virtual machine monitor (VMM). Virtualization layer 1950 can present a virtual operating platform to virtual machines 1940 that appears to be networked hardware.

[0133] like Figure 19 As shown, hardware 1930 can be a standalone network node with common or specialized components. Hardware 1930 may include antenna 19225 and may implement some functionality via virtualization. Alternatively, hardware 1930 may be part of a larger hardware cluster (e.g., such as in a data center or customer premises equipment (CPE)) where many hardware nodes work together and are managed via management and orchestration (MANO) 19100, which oversees, among other things, the lifecycle management of application 1920.

[0134] In some contexts, virtualization of hardware is referred to as network function virtualization (NFV). NFV can be used to consolidate many network device types onto industry-standard high-volume server hardware, physical switches, and physical storage devices (which can be located in a data center), as well as client devices.

[0135] In the context of NFV, a virtual machine 1940 can be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each virtual machine 1940 and the portion of the hardware 1930 on which it executes, whether dedicated to that virtual machine and / or shared with other virtual machines 1940, form a separate virtual network element (VNE).

[0136] Still in the context of NFV, a virtual network function (VNF) is responsible for handling specific network functions running in one or more virtual machines 1940 on top of the hardware networking infrastructure 1930 and corresponds to Figure 19 Application in 1920.

[0137] In some embodiments, one or more radio units 19200, each including one or more transmitters 19220 and one or more receivers 19210, may be coupled to one or more antennas 19225. The radio units 19200 may communicate directly with the hardware nodes 1930 via one or more suitable network interfaces and may be used in combination with virtual components to provide a virtual node with radio capabilities, such as a radio access node or base station.

[0138] In some embodiments, some signaling may be implemented using a control system 19230 , which may alternatively be used for communications between the hardware node 1930 and the radio unit 19200 .

[0139] Remote host computer operations

[0140] refer to Figure 20According to an embodiment, a communications system includes a telecommunications network 2010, such as a 3GPP-type cellular network, including an access network 2011, such as a radio access network, and a core network 2014. Access network 2011 includes multiple base stations 2012a, 2012b, and 2012c, such as NBs, eNBs, gNBs, or other types of wireless access points, each defining a corresponding coverage area 2013a, 2013b, and 2013c. Each base station 2012a, 2012b, and 2012c is connectable to core network 2014 via a wired or wireless connection 2015. A first UE 2091 located in coverage area 2013c is configured to wirelessly connect to or be paged by a corresponding base station 2012c. A second UE 2092 located in coverage area 2013a is wirelessly connectable to a corresponding base station 2012a. Although multiple UEs 2091 and 2092 are shown in this example, the disclosed embodiments are equally applicable to situations where only one UE is in the coverage area or only one UE is connecting to the corresponding base station 2012.

[0141] Telecommunications network 2010 itself is connected to a host computer 2030, which may be embodied in the hardware and / or software of a standalone server, a cloud-enabled server, a distributed server, or as processing resources in a server farm. Host computer 2030 may be owned or controlled by a service provider, or may be operated by or on behalf of a service provider. Connections 2021 and 2022 between telecommunications network 2010 and host computer 2030 may extend directly from core network 2014 to host computer 2030, or may pass through an optional intermediary network 2020. Intermediary network 2020 may be one or a combination of public, private, or managed networks; intermediary network 2020, if present, may be a backbone network or the Internet; in particular, intermediary network 2020 may include two or more subnetworks (not shown).

[0142] Figure 20The communication system as a whole enables connectivity between connected UEs 2091, 2092 and a host computer 2030. This connectivity can be described as an over-the-top (OTT) connection 2050. The host computer 2030 and the connected UEs 2091, 2092 are configured to communicate data and / or signaling via the OTT connection 2050, using the access network 2011, the core network 2014, any intermediate networks 2020, and possible further infrastructure (not shown) as intermediaries. The OTT connection 2050 may be transparent in the sense that the participating communication devices traversing the OTT connection 2050 are unaware of the routing of uplink and downlink communications. For example, there may be no need or necessity to inform the base station 2012 about the past routing of incoming downlink communications that forwarded (e.g., handed over) data originating from the host computer 2030 to the connected UE 2091. Similarly, base station 2012 does not need to know the future routing of outgoing uplink communications from UE 2091 to host computer 2030.

[0143] According to the embodiment, reference will now be made to Figure 21 Describes an example implementation of the UE, base station, and host computer discussed in the previous paragraphs. In the communication system 2100, the host computer 2110 includes hardware 2115, which includes a communication interface 2116 configured to establish and maintain a wired or wireless connection with the interface of the different communication devices of the communication system 2100. The host computer 2110 further includes processing circuitry 2118, which may have storage and / or processing capabilities. In particular, the processing circuitry 2118 may include one or more programmable processors, application-specific integrated circuits, field-programmable gate arrays, or a combination thereof (not shown) suitable for executing instructions. The host computer 2110 further includes software 2111, which is stored in or accessible by the host computer 2110 and is executable by the processing circuitry 2118. The software 2111 includes a host application 2112. The host application 2112 is operable to provide services to a remote user (such as a UE 2130 connected via an OTT connection 2150 terminated at the UE 2130 and the host computer 2110). When providing services to remote users, the host application 2112 may provide user data transmitted using the OTT connection 2150 .

[0144] The communication system 2100 further includes a base station 2120, which is provided in the telecommunication system and includes hardware 2125 that enables it to communicate with the host computer 2110 and the UE 2130. The hardware 2125 may include a communication interface 2126 for establishing and maintaining wired or wireless connections with different communication devices of the communication system 2100 and a communication interface 2126 for communicating with devices located in the coverage area ( Figure 21The UE 2130 in the embodiment (not shown) establishes and maintains a radio interface 2127 for at least a wireless connection 2170. The communication interface 2126 may be configured to facilitate a connection 2160 to the host computer 2110. The connection 2160 may be direct or it may be via a core network ( Figure 21 The base station 2120 may also include a plurality of communication channels (not shown) and / or through one or more intermediate networks external to the telecommunications system. In the illustrated embodiment, the hardware 2125 of the base station 2120 further includes processing circuitry 2128, which may include one or more programmable processors, application specific integrated circuits, field programmable gate arrays, or combinations thereof (not shown) suitable for executing instructions. The base station 2120 further includes software 2121 stored internally or accessible via an external connection.

[0145] The communication system 2100 further comprises the already mentioned UE 2130. Its hardware 2135 may comprise a radio interface 2137 configured to establish and maintain a wireless connection 2170 with a base station serving the coverage area in which the UE 2130 is currently located.

[0146] The hardware 2135 of the UE 2130 further includes processing circuitry 2138, which may include one or more programmable processors, application-specific integrated circuits, field-programmable gate arrays, or a combination thereof (not shown) suitable for executing instructions. The UE 2130 further includes software 2131 stored in or accessible by the UE 2130 and executable by the processing circuitry 2138. The software 2131 includes a client application 2132. The client application 2132 is operable to provide services to human or non-human users via the UE 2130 with the support of the host computer 2110. In the host computer 2110, the executing host application 2112 can communicate with the executing client application 2132 via an OTT connection 2150 terminated at the UE 2130 and the host computer 2110. When providing services to users, the client application 2132 can receive request data from the host application 2112 and provide user data in response to the request data. The OTT connection 2150 can transmit both the request data and the user data. The client application 2132 may interact with the user to generate the user data that it provides.

[0147] Notice, Figure 21 The host computer 2110, base station 2120 and UE 2130 shown in FIG can be respectively Figure 20 The host computer 2030, one of the base stations 2012a, 2012b, 2012c and one of the UEs 2091, 2092 are similar or identical. That is, the internal workings of these entities may be similar to or identical to Figure 21 shown, and independently, the surrounding network topology can be Figure 20 network topology.

[0148] exist Figure 21 In FIG, an OTT connection 2150 is abstractly drawn to illustrate communication between a host computer 2110 and a UE 2130 via a base station 2120, without explicitly mentioning any intermediary devices and the precise message routing through these devices. The network infrastructure can determine the routing, which can be configured to hide the routing from the UE 2130, the service provider operating the host computer 2110, or both. While the OTT connection 2150 is active, the network infrastructure can further make decisions that dynamically change the routing (e.g., based on load balancing considerations or network reconfiguration).

[0149] The wireless connection 2170 between the UE 2130 and the base station 2120 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improves the performance of an OTT service provided to the UE 2130 using the OTT connection 2150, with the wireless connection 2170 forming the final leg. More specifically, the teachings of these embodiments can improve latency, among other things, and thereby provide benefits such as better responsiveness.

[0150] A measurement process may be provided for the purpose of monitoring data rate, latency, and other factors to be improved by one or more embodiments. Optional network functionality may further be present to reconfigure the OTT connection 2150 between the host computer 2110 and the UE 2130 in response to changes in the measurement results. The measurement process and / or network functionality for reconfiguring the OTT connection 2150 may be implemented in the software 2111 and hardware 2115 of the host computer 2110, or in the software 2131 and hardware 2135 of the UE 2130, or in both. In embodiments, sensors (not shown) may be deployed in or in conjunction with the communication device through which the OTT connection 2150 passes. The sensors may participate in the measurement process by supplying values ​​for the monitored quantities exemplified above or other physical quantities from which the software 2111 and 2131 can calculate or estimate the monitored quantities. Reconfiguration of the OTT connection 2150 may include message formats, retransmission settings, preferred routing, and the like. The reconfiguration need not affect the base station 2120 and may be unknown or imperceptible to the base station 2120. Such processes and functionality are known and practiced in the art. In certain embodiments, the measurements may involve proprietary UE signaling that facilitates the host computer 2110 to measure throughput, propagation time, latency, etc. The measurements are possible because the software 2111 and 2131 enables the use of OTT connection 2150 to transmit messages, particularly empty or 'dummy' messages, while monitoring propagation time, errors, etc.

[0151] Figure 22is a flow chart showing a method implemented in a communication system according to one embodiment. The communication system includes a host computer, a base station and a UE, which may be a reference Figure 20 and Figure 21 To simplify this disclosure, this section will only include Figure 22 Reference is made to the accompanying drawings of FIG. In step 2210, the host computer provides user data. In sub-step 2211 of step 2210 (which may be optional), the host computer provides the user data by executing a host application. In step 2220, the host computer initiates a transmission carrying the user data to the UE. In step 2230 (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station transmits the user data carried in the transmission initiated by the host computer to the UE. In step 2240 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.

[0152] Figure 23 is a flow chart showing a method implemented in a communication system according to one embodiment. The communication system includes a host computer, a base station and a UE, which may be a reference Figure 20 and Figure 21 To simplify this disclosure, this section will only include Figure 23 Reference is made to the accompanying drawings of the present invention. In step 2310 of the method, the host computer provides user data. In an optional sub-step (not shown), the host computer provides the user data by executing a host application. In step 2320, the host computer initiates a transmission carrying the user data to the UE. According to the teachings of the embodiments described throughout this disclosure, the transmission may pass through a base station. In step 2330 (which may be optional), the UE receives the user data carried in the transmission.

[0153] As described above, exemplary embodiments provide methods and corresponding devices comprised of various modules that provide functionality for performing the steps of these methods. These modules can be implemented as hardware (embodied in one or more chips, including integrated circuits such as application-specific integrated circuits) or as software or firmware for execution by a processor. In particular, in the case of firmware or software, exemplary embodiments can be provided as a computer program product comprising a computer-readable storage medium on which computer program code (i.e., software or firmware) is embodied for execution by a computer processor. The computer-readable storage medium can be non-transitory (e.g., a magnetic disk, an optical disk, read-only memory, a flash memory device, a phase-change memory) or transient (e.g., an electrical, optical, acoustic, or other form of propagated signal, such as a carrier wave, an infrared signal, a digital signal, etc.). The processor and other components are typically coupled via one or more buses or bridges (also known as bus controllers). The storage device and the signal carrying the digital traffic represent one or more non-transitory or transient computer-readable storage media, respectively. Thus, the storage device of a given electronic device typically stores code and / or data for execution on a collection of one or more processors of that electronic device (e.g., a controller).

[0154] Although the embodiments and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the spirit and scope thereof as defined by the appended claims. For example, many of the features and functions discussed above may be implemented using software, hardware, or firmware, or a combination thereof. Furthermore, many of the features, functions, and steps involved in operating them may be reordered, omitted, added, etc., and still fall within the broad scope of the various embodiments.

[0155] Some example embodiments of the present disclosure are provided in the following enumerated list, but the present disclosure is not limited thereto.

[0156] Example Embodiments

[0157] 1. A method (900) in a wireless device (105) operable in a wireless communication network (100) of identifying reference signal resources to be used in transmissions by the wireless device, the method comprising: receiving (S905) signaling configuring the wireless device to use a plurality of reference signal resource groups, each group comprising a plurality of reference signal resources; receiving (S910) in a control channel an indication of reference signal resources to be used, wherein the reference signal resources to be used comprise first and second reference signal resources selected from respective first and second reference signal resource groups selected only from the plurality of reference signal resource groups; and using (S915) the first and second reference signal resources in a reference signal transmission to a network node in the network.

[0158] 2. The method of embodiment 1, wherein the reference signal resource is a sounding reference signal (SRS) resource.

[0159] 3. A method for identifying one or more SRS resources to be used in a transmission performed by the wireless device in a wireless device operable in a wireless communication network, the method comprising: receiving signaling configuring the wireless device to use multiple SRS resource groups, each group including multiple SRS resources; receiving an indication of the SRS resources to be used in a physical layer downlink control channel; determining a first and a second SRS resource group based on the indication, wherein the first and second SRS resource groups are selected from the multiple SRS resource groups; determining a first SRS resource selected only from the first SRS resource group based on the indication; determining a second SRS resource selected only from the second SRS resource group based on the indication; and transmitting at least one of: a) an SRS identified by the first and second SRS resources, and b) a first and a second MIMO layer of the transmission based on the first and second SRS resources, respectively.

[0160] 4. The method of embodiment 3, wherein the size of the field used to signal the indication is determined based on the maximum number of MIMO layers that the wireless device is configured to transmit, the number of SRS resource groups from which SRS resources can be selected, and the number of SRS resources in the multiple SRS resource groups.

[0161] 5. A method for identifying one or more SRS resources to be used in a transmission performed by a wireless device operable in a wireless communication network, the method comprising: receiving signaling to configure the wireless device to use multiple SRS resources; receiving an indication of the SRS resources to be used in a physical layer downlink control channel; determining, based on the indication, a first and a second SRS resource that should be used in a given transmission from the multiple SRS resources, wherein the first and second SRS resources can be any SRS resources in the multiple SRS resources, except where the first and second SRS resources are the same; and transmitting at least one of: a) an SRS identified by the first and second SRS resources, and b) a first and a second MIMO layer of a transmission based on the first and second SRS resources, respectively.

[0162] 6. The method of embodiment 5, wherein the first and second SRS resources are each identified in the multiple SRS resources by a first and second index, respectively; and the step of determining the first and second SRS resources according to the indication further has a further exception of selecting the first index and the second index in a single fixed order, the single fixed order being one of the following: a) the first index is always greater than the second index, and b) the first index is always less than the second index.

[0163] 7. A method for identifying one or more SRS resources to be used in transmissions performed by the wireless device in a wireless device operable in a wireless communication network, the method comprising: receiving signaling to configure the wireless device to use a first SRS resource group among the multiple SRS resource groups, the first SRS resource group including multiple SRS resources; receiving an indication of the SRS resources to be used in a physical layer downlink control channel; determining a first SRS resource selected only from the first SRS resource group based on the indication; and transmitting at least one of: a) an SRS identified by the first SRS resource, and b) a MIMO layer of the transmission based on the first SRS resource.

[0164] 8. A method (1100) in a network node for configuring reference signal transmission settings in a wireless device, the wireless device being operable in a wireless communication network, the method comprising: determining (S1105) a total number of possible reference signal states based on grouping reference signal resources into reference signal resource groups, the grouping being configured such that only one reference signal resource can be selected from each reference signal resource group for use in transmission; determining (S1110) a mapping of different combinations of reference signal indicator bits to corresponding reference signal states in the possible reference signal states; signaling (S1115) the mapping to the wireless device; determining (S1120) one or more preferred reference signal resources for UL transmission from the wireless device; and signaling (S1125) the reference signal indicator bit to the wireless device, which is mapped by mapping to the SRI states corresponding to the one or more preferred reference signal resources.

[0165] 9. The method of embodiment 8, wherein determining the total number of possible SRI states based on the grouping of SRS resource groups comprises fixing the order in which the SRS resources are mapped to the MIMO layers, thereby limiting the total number of possible SRI states.

[0166] 10. The method of embodiment 8, wherein determining the total number of possible SRI states based on the grouping of SRS resource groups includes accounting for mapping the SRS resources to the MIMO layers in any of a plurality of desired orders.

[0167] 11. The method of any one of embodiments 8-10, wherein the reference signal resource is a sounding reference signal (SRS) resource.

[0168] 12. A wireless device (105, 200) for facilitating communications in a wireless communication network (100) by obtaining an indication of reference signal resources to use, the wireless device comprising processing circuitry configured to perform the steps of any one of embodiments 1-7.

[0169] 13. A network node (110, 300) for configuring reference signal resources in a wireless communication network (100), the network node comprising processing circuitry configured to perform the steps of any one of embodiments 8-11.

[0170] 14. A user equipment (UE) (200) for facilitating communication in a wireless communication network (100) by obtaining an indication of reference signal resources to be used, the UE comprising: an antenna (220) configured to transmit and receive wireless signals; a transceiver (215) connected to the antenna and processing circuitry (205) and configured to condition signals passed between the antenna and the processing circuitry; the processing circuitry configured to perform the steps of any one of embodiments 1-7.

[0171] 15. A communication system comprising a host computer, the host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a wireless device, wherein the cellular network comprises a network node having: a) a communication interface configured to receive user data; b) a radio interface configured to interface with the wireless device to forward the user data to the wireless device; and c) processing circuitry configured to perform the steps of any one of embodiments 8-11.

[0172] 16. The communication system of any of the preceding embodiments further includes a network node.

[0173] 17. The communication system of any one of the preceding two embodiments, further comprising a wireless device, wherein the wireless device is configured to communicate with a network node.

[0174] 18. The communication system of any of the preceding three embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application to provide the user data; and the wireless device includes a processing circuitry configured to execute a client application associated with the host application.

[0175] 19. A method implemented in a communication system including a host computer, a network node and a wireless device, the method comprising: providing user data at the host computer; and initiating, at the host computer, transmission of the user data to the wireless device via a cellular network including the network node, wherein the network node performs the steps of any one of embodiments 1-16.

[0176] 20. The method of the preceding embodiment, further comprising transmitting user data at the network node.

[0177] 21. The method of any of the two preceding embodiments, wherein the user data is provided by executing a host application at the host computer, the method further comprising executing a client application associated with the host application at the wireless device.

[0178] 22. A communication system comprising a host computer and a wireless device, the host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to the wireless device, wherein the wireless device comprises a transceiver and processing circuitry, the components of the wireless device being configured to perform the steps of any one of embodiments 1-7.

[0179] 23. The communication system of the preceding embodiment, wherein the cellular network further comprises a network node configured to communicate with the wireless device.

[0180] 24. The communication system of any of the preceding two embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application to provide user data; and the processing circuitry of the wireless device is configured to execute a client application associated with the host application.

[0181] 25. A method implemented in a communication system including a host computer, a network node and a wireless device, the method comprising: providing user data at the host computer; and initiating transmission at the host computer to carry the user data to the wireless device via a cellular network including the network node, wherein the wireless device performs the steps of any one of embodiments 1-7.

[0182] 26. The method of the preceding embodiment, further comprising receiving user data at the wireless device from the network node.

[0183] 3GPP submission

[0184] The following description provides examples of how certain aspects of the embodiments described herein may be implemented within the framework of specific communication standards. In particular, the following examples provide non-limiting examples of how the embodiments described herein may be implemented within the framework of 3GPP RAN standards. The variations described by these examples are intended merely to illustrate how certain aspects of the embodiments may be implemented within specific standards. However, the embodiments may also be implemented in other suitable manners within 3GPP specifications and other specifications or standards.

[0185] Title: UL MIMO based on non-codebook transmission

[0186] 1-Introduction

[0187] In RAN1-NRAH3, the following agreements were reached online and offline:

[0188] The following were agreed upon in RAN1#90: 1) For PUSCH precoder determination in non-codebook-based UL MIMO, support for Alt. 1 (i.e., only SRI and no TPMI indication in at least the UL grant) for wideband indication. Note: The gNB should only signal the SRI(s) so that the UE can simultaneously perform UL precoded transmissions inferred from the signaled SRI(s). FFS details. FFS: If subband indication is supported, select Alt. 1-3 for it. 2) Specify the UE capability that identifies whether a UE with UL MIMO can support coherent transmission across its transmit chains. FFS: Whether the UE capability identifies whether coherent transmission is supported on all transmit chains, versus none, versus a subset of its transmit chains. FFS: How the UL MIMO precoding design accounts for these capabilities.

[0189] While it was agreed in the offline discussion at RANI NRAH#3 [1] that for non-codebook based transmission, SRI(s) may be used to indicate a total of up to 4 SRS ports, it is noted that for non-codebook based precoding, each SRS resource contains one port.

[0190] In this contribution, we discuss non-codebook based UL transmissions and present some further details on SRI indication. In particular, we address the open issues of how the UE should signal the SRI(s) so that UL precoding inferred from the SRI(s) can be performed by the UE simultaneously, how the SRI signaling should take this into account, and the need for frequency selective signaling of the SRI.

[0191] 2-Non-codebook based UL transmission

[0192] SRS resources can be narrowband and therefore occupy only a portion of the entire frequency band. However, the SRI(s) that determine the preferred SRS resource(s) should be considered wideband, meaning that the SRI(s) should apply to the entire bandwidth of the corresponding PUSCH transmission. For example, if wideband precoding of SRS resources is used, the UE simply applies the same precoding to the entire PUSCH allocation. If frequency-selective precoding of SRS resources is used, a UE should not be expected to be scheduled on a resource allocation for which it has not previously transmitted SRS.

[0193] Frequency-selective UL closed-loop precoding has not been shown to provide substantial gains so far, at least over codebook-based precoding [2][3][4]. Reciprocity-based high-resolution precoding may have additional gain potential and also avoid the additional overhead of frequency-selective SRI. If full reciprocity cannot be exploited, frequency-selective precoding can be implemented for non-codebook-based UL transmissions by using frequency-selective SRI. However, this will also result in increased overhead signaling, so further research will be needed to evaluate the performance gains of such schemes versus the overhead.

[0194] Proposal 1: There is a need to further study frequency-selective SRI considering the performance gain versus overhead of non-codebook based UL transmission.

[0195] Some UEs may not have calibrated (or only partially calibrated) their radio chains, which means that the UE does not know the relative phases of the transmit chains. In this case, precoding (i.e., coherent transmission) will be difficult to apply in a useful way. Therefore, support for a UE capability that identifies whether a UE with UL MIMO capability can support coherent transmission across its transmit chains was agreed in RAN1#90. When a UE cannot transmit coherently on any of its Tx chains, it is best if the UE allocates one SRS resource per antenna arrangement, which corresponds to Figure 25 The TRP can then select the antenna arrangement that should be used for UL transmission by reporting one or several SRIs, where each SRI applies to one layer.

[0196] 3-SRS Resource Group

[0197] The concept of UL beam management (i.e., beam management based on UL reference signals) is currently being developed for NR in order to control the beams (or more precisely, the effective antenna patterns) of the corresponding UE antenna subsets. UL beam management is expected to be performed by having the UE transmit different SRS resources in different UE antenna subset beams, with the TRP performing RSRP measurements on these SRS resources and signaling back the SRI(s) corresponding to the SRS resource(s) with the highest RSRP value(s). If a multi-antenna subset UE is scheduled for SRS transmission from multiple beams from each of the multiple antenna subsets, the TRP and the UE need to have mutual agreement on which combinations of SRS resources can be transmitted simultaneously from the different antenna subsets. Otherwise, the TRP may select SRS resources that cannot be transmitted simultaneously, such as when the SRS resources correspond to different switched analog beams in the same antenna subset. The following comments on the agreement for signaling multiple SRIs from RAN1#90 (below) address this issue, but do not conclude how it should be done. NOTE: The gNB shall only signal the SRI(s) so that the UE can simultaneously perform UL precoded transmissions inferred from the signaled SRI(s).

[0198] One way to address this problem is to identify SRS resource groups, where only one resource in an SRS resource group can be transmitted at a time. This one resource from each SRS resource group can be transmitted simultaneously with each of the other selected SRS resources from other groups. Assuming the number of SRS resource groups and which SRS resources are in a group is known, the TRP can determine which SRS resources it can direct the UE to transmit when signaling multiple SRS resources. An example is given below:

[0199] Assume that the UE has two antenna subsets (e.g., panels) (antenna subset / panel A and antenna subset / panel B), where each antenna subset has four simulated beams (A1-A4 and B1-B4), as shown in Figure 5As shown. The UE will start by signaling to the TRP in the UE capabilities that it has two SRS resource groups, where each SRS resource group consists of four SRS resources. For example, a total of SRS resources may be configured where SRS resources 1-4 may belong to a first SRS resource group (corresponding to antenna subset A) and SRS resources 5-8 may belong to a second SRS resource group (corresponding to antenna subset B). During the UE TX beam scanning process (i.e., U3), the TRP may trigger these 8 SRS resources (via an indication in the aperiodic SRS transmission request) and the TRP will know which SRS resources can and cannot be transmitted simultaneously given the SRS resource grouping. The TRP may then perform measurements on the eight transmitted SRS resources, determine the best SRS resource for each SRS resource group, and signal the corresponding SRI back to the UE. Note that each SRS resource can consist of one or several SRS ports, so this process is applicable to both non-codebook-based UL transmission (single SRS port per SRS resource) and codebook-based UL transmission (one or several SRS ports per SRS resource). However, note that for non-codebook-based UL transmission that allows precoding each SRS resource on multiple antenna ports, in this case (i.e., when UL beam management is present), SRS precoding should not be applied to antenna ports belonging to different antenna subsets (because that would break the mutual agreement that a certain SRS resource belongs only to a certain antenna subset).

[0200] We note that here, the concept of SRS resource group has a similar purpose as the DMRS port group defined for NR downlink and the SRS port group proposed in [5]. Assuming that SRI refers to SRS resource, and since SRS antenna port group would seem to imply some kind of selection or subdivision within one SRS resource, 'SRS resource group' seems to be more appropriate to describe the expected behavior.

[0201] Proposal 2: Define an SRS resource group, wherein it can be assumed that a UE can only transmit one SRS resource in an SRS resource group at a time, and wherein the UE can transmit one SRS resource from each of a plurality of SRS resource groups simultaneously.

[0202] 4 – Using the SRS resource group in the SRI indication

[0203] To indicate multiple SRSs in the DCI, one option is to use a bitmap of size N, where N is the number of SRS resources (corresponding to the maximum rank), and each bit indicates whether an SRS resource should be used to transmit a PUSCH layer. However, this is not a very efficient signaling approach and thus wastes DCI overhead.

[0204] Another option is to jointly indicate which SRS resources should be used for each rank and then jointly encode the TRI and multiple SRIs. In this case, the SRI signaling from the TRP to the UE is indicated by possible SRI states, where is the number of combinations of taking k values ​​from N values ​​at a time, and N is the number of SRS resources, L is the transmission rank, and L max is the maximum transmission rank that the UE can achieve. For example, when N=8 and L max = 2, so the total number of possible SRI states is This means that 6 bits are required to indicate the selected SRI state to the UE, in contrast to N=8 bits if a bitmap approach of size N is used.

[0205] By considering constraints on SRS and / or PUSCH MIMO layer transmission, it is possible to further reduce the SRI overhead. For example, assume that the UE has two antenna subsets (e.g., panels) and each antenna subset has four simulated beams, such as Figure 5 In this case, many possible SRI states will not be allowed, because only one SRS resource can be selected from each SRS resource group. Therefore, in this case, it is preferable to map between possible SRI states and SRI signaling bits in order to reduce overhead. For example, DCI signaling can indicate One of the M states, indicating which of the M SRS resource groups is used to transmit the L layers, and then indicating the SRS resource to be used in each selected SRS resource group. For example, if each group has 4 SRS resources, 4 states are required to select a resource from the group. Then, in the case of M=2 resource groups and at most L max = 2 layers, there are a total of states, so assuming that SRS grouping is considered when signaling SRI in this case, 5 bits can be used to signal SRI.

[0206] Observation 1: By considering the SRS resource group during SRI signaling, the overhead of SRI signaling can be reduced.

[0207] Proposal 3: Consider SRS resource grouping when signaling multiple SRI indications in DCI.

[0208] 5-Conclusion

[0209] In this contribution, we discuss non-codebook-based UL transmission and further details on SRI indication. In particular, we address the open issues of how the UE should signal the SRI(s) so that the UE can simultaneously perform UL precoding inferred from the SRI(s), how the SRI signaling should account for this, and the need for frequency-selective signaling of the SRI. Our analysis leads to the following observations and recommendations:

[0210] Observation 1: By considering the SRS resource group during SRI signaling, the overhead of SRI signaling can be reduced.

[0211] Proposal 1: There is a need to further study frequency-selective SRI considering the performance gain versus overhead of non-codebook based UL transmission.

[0212] Proposal 2: Define an SRS resource group, wherein it can be assumed that a UE can only transmit one SRS resource in an SRS resource group at a time, and wherein the UE can transmit one SRS resource from each of a plurality of SRS resource groups simultaneously.

[0213] Proposal 3: Consider SRS resource grouping when signaling multiple SRI indications in DCI.

[0214] 6- References

[0215] Rl-1716921, “Summary of offline discussion on UL MIMO Open Issues,” Ericsson, 3GPP TSG RAN WG1 NR#3, Nagoya, Japan, September 18-21, 2017

[0216] Rl-1708669, “UL MIMO procedures for codebook-based transmission,” Ericsson, 3GPP TSG RAN WG1 Meeting #89, Hangzhou, China, May 15-19, 2017

[0217] Rl-1711008, “UL MIMO procedures for codebook-based transmission,” Ericsson, 3GPP TSG RAN WG1 Meeting #89adhoc 2, Qingdao, China, June 27-30, 2017

[0218] Rl-1714271, “UL MIMO for codebook-based transmission”, Ericsson, 3GPPTSG RAN WG1 Meeting #90, Prague, Czech Republic, August 21-25, 2017

[0219] Rl-1709735, “Way Forward on Uplink Multi-panel and Multi-TRP operation,” Intel et al., 3GPP TSG RAN WG1 Meeting #89, Hangzhou, China, May 15-19, 2017

[0220] List of abbreviations

[0221] TRP - Transmission / Reception Point

[0222] UE - User Equipment

[0223] NW-Network

[0224] BPL - Beam Pair Link

[0225] BLF - Beam Pair Link Failure

[0226] BLM - Beam Pair Link Monitoring

[0227] BPS-Beam Pair Link Switching

[0228] RLM - Radio Link Monitoring

[0229] RLF - Radio Link Failure

[0230] PDCCH - Physical Downlink Control Channel

[0231] RRC - Radio Resource Control

[0232] CRS - Cell-specific Reference Signal

[0233] CSI-RS - Channel State Information Reference Signal

[0234] RSRP - Reference Signal Received Power

[0235] RSRQ - Reference Signal Received Quality

[0236] gNB-NR base station

[0237] PRB - Physical Resource Block

[0238] RE - Resource Element

Claims

1. A method (1300) in a wireless device (105) operable in a wireless communication network (100) of identifying reference signal resources to be used in transmissions by the wireless device, the method comprising: receiving ( S905 ) signaling for configuring a plurality of SRS resources for the wireless device; receiving (S1310) in a control channel an indication of a selected plurality of SRS resources, the selected plurality of SRS resources being selected from the plurality of configured SRS resources to be used in a transmission; as well as determining (S1315) the selected plurality of SRS resources that should be used in the transmission from the indication; and transmitting (S1320) multiple MIMO layers of a PUSCH transmission, The selected multiple SRS resources are mapped to corresponding layers in the multiple MIMO layers, wherein the indication of the selected multiple SRS resources includes SRS resource indexes having a fixed order corresponding to the order in which the SRS resources in the selected multiple SRS resources are mapped to the MIMO layers, and wherein the size of the field for indicating the SRS resource index is determined based on the maximum number of MIMO layers that the wireless device is configured to transmit.

2. The method according to claim 1, wherein The indication of the selected plurality of SRS resources indicates entries of a table, wherein the table comprises only one entry for each possible ordering of combinations of SRS resources.

3. The method according to claim 1, wherein The signaling configuring a plurality of SRS resources for the wireless device indicates grouping the plurality of SRS resources into a plurality of SRS resource groups, each group including a plurality of SRS resources, and wherein each SRS resource of the selected plurality of SRS resources is selected from the same SRS resource group.

4. A wireless device (105, 200) for facilitating communications in a wireless communication network (100) by obtaining an indication of reference signal resources to use, the wireless device comprising processing circuitry configured to perform the method of any one of claims 1-3.

5. A user equipment (UE) (200) for facilitating communication in a wireless communication network (100) by obtaining an indication of reference signal resources to be used, the UE comprising: an antenna (220) configured to transmit and receive wireless signals; as well as A transceiver (215) connected to the antenna and processing circuit (205) and configured to condition signals communicated between the antenna and the processing circuit, the processing circuit configured to perform the method of any one of claims 1-3.

6. A method (1700) of configuring and instructing, in a network node, usage of a reference signal transmission setting in a wireless device operable in a wireless communication network, the method comprising: transmitting ( S1705 ) signaling for configuring a plurality of SRS resources for the wireless device; as well as transmitting (S1710) in a control channel an indication of a selected plurality of SRRS resources, the selected plurality of SRS resources being selected from the plurality of configured SRS resources to be used in a transmission, receiving (S1715) a plurality of MIMO layers, wherein the selected plurality of SRS resources are mapped to corresponding layers of the plurality of MIMO layers, wherein the indication of the selected plurality of SRS resources comprises SRS resource indices having a fixed order, the fixed order corresponding to the order in which the SRS resources in the selected plurality of SRS resources are mapped to the MIMO layer, and The size of the field for indicating the SRS resource index is determined according to the maximum number of MIMO layers that the wireless device is configured to transmit.

7. The method according to claim 6, wherein: The indication of the selected plurality of SRS resources indicates entries of a table, wherein the table comprises only one entry for each possible ordering of combinations of SRS resources.

8. The method of claim 6, wherein: The signaling configuring a plurality of SRS resources for the wireless device indicates grouping the plurality of SRS resources into a plurality of SRS resource groups, each group including a plurality of SRS resources, and wherein each SRS resource of the selected plurality of SRS resources is selected from the same SRS resource group.

9. A network node (110, 300) for configuring reference signal resources in a wireless communication network (100), the network node comprising processing circuitry configured to perform the method according to any one of claims 6 to 8.

10. A communication system (2100), comprising a host computer (2110), the host computer (2110) comprising: a first processing circuit (2118) configured to provide user data; as well as a first communication interface (2116) configured to forward the user data to a cellular network for transmission to a wireless device (2130), The cellular network includes a network node (2120), wherein the network node (2120) has: a second communication interface (2126), configured to receive the user data; a radio interface (2127) configured to interface with a wireless device (2130) to forward the user data to the wireless device (21230); and A second processing circuit (2128) configured to execute the method according to any one of claims 6 to 8. The communication system of claim 10 , further comprising the network node.

12. The communication system of claim 10 or 11, further comprising the wireless device, wherein the wireless device is configured to communicate with the network node.

13. The communication system according to any one of claims 10 to 11, wherein: the first processing circuit of the host computer being configured to execute a host application, thereby providing the user data; and The wireless device includes a third processing circuit configured to execute a client application associated with the host application.

14. A method implemented in a communication system comprising a host computer, a network node, and a wireless device, the method comprising: providing user data at said host computer; as well as At the host computer, a transmission carrying the user data is initiated to the wireless device via a cellular network including the network node, wherein the network node performs the method according to any one of claims 6 to 8.

15. The method of claim 14, further comprising transmitting the user data at the network node.

16. The method of claim 14 or 15, wherein the user data is provided at the host computer by executing a host application, the method further comprising executing a client application associated with the host application at the wireless device.

17. A communication system (2100) comprising a host computer (2110) and a wireless device (2130), the host computer comprising: processing circuitry configured to provide user data; as well as a communication interface configured to forward user data to a cellular network for transmission to a wireless device (2130), The wireless device (2130) comprises a transceiver and a processing circuit, and the components of the wireless device are configured to perform the method according to any one of claims 1 to 3.

18. The communication system of claim 17, wherein the cellular network further comprises a network node (2120) configured to communicate with the wireless device.

19. The communication system according to claim 17 or 18, wherein: the processing circuitry of the host computer being configured to execute a host application, thereby providing the user data; and The processing circuitry of the wireless device is configured to execute a client application associated with the host application.

20. A method implemented in a communication system (2100) comprising a host computer (2110), a network node (2120), and a wireless device (2130), the method comprising: providing user data at said host computer; as well as At the host computer, a transmission carrying the user data is initiated to the wireless device via a cellular network including the network node, wherein the wireless device executes the method according to any one of claims 1 to 3.

21. The method of claim 20, further comprising receiving, at the wireless device, the user data from the network node.

Images