Uplink Timing Advance Loop Management

Abstract

Aspects and embodiments relate to apparatus and methods for uplink timing advance loop management. One aspect provides a user equipment comprising: means for indicating to another node that multiple timing advance loops are supported; means for receiving from the other node a configuration for measuring received reference signals from the other node; means for performing measurements on the received reference signals in accordance with the configuration; means for evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the other node or an additional node based on conditional use of at least one timing advance loop; and means for transmitting information related to the evaluated indication of the predicted signal quality metric associated with the other node or at least one of the additional node. As a result of the method performed by the user equipment, information can be provided to other nodes in the network to facilitate intelligent selection of use of one or more timing advance loops by the user equipment.

Description

[Technical Field]

[0001] Various illustrative embodiments relate to apparatus and methods for uplink timing advance loop management. [Background technology]

[0002] A timing advance (TA) loop is implemented in a network to enable user equipment to control and adjust uplink transmission timing to facilitate alignment of uplink signals at the receiving node. TA commands or values ​​are sent by the network to the user equipment to achieve uplink signal alignment. In a multiple transmission / reception point (TRP) enabled network, the user equipment may be able to connect to multiple transmission / reception points (m-TRPs). Some adaptation of the timing advance technique may be required to facilitate user equipment operation in m-TRP scenarios. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] H. Steendam, M. Moenclaey, "Analysis and Optimization of the Performance of OFDM on Frequency-Selective Time-Selective Fading Channels", IEEE Trans.Commun.vol.47, pp.1811-1819, December 1999. [Non-patent document 2] M. Batariere, K. Braum, TPKrauss, "Cyclic Prefix Length Analysis for 4G OFDM Systems", VTC'04, Los Angeles, USA, September 2004. Summary of the Invention [Means for solving the problem]

[0004] The scope of protection sought for various example embodiments of the present invention is set out in the independent claims. To the extent that there are example embodiments and features described herein that do not fall within the scope of the independent claims, they should be construed as examples that are useful for understanding various embodiments of the present invention.

[0005] According to various, but not necessarily all, example embodiments, an apparatus is provided that includes: means for indicating to another node that multiple timing advance loops are supported; means for receiving from the other node a configuration for measuring received reference signals from the other node; means for performing measurements on the received reference signals in accordance with the configuration; means for evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the other node or a further node based on the conditional use of at least one timing advance loop; and means for transmitting information related to the evaluated indication of the predicted signal quality metric at at least one of the other node and the further node.

[0006] According to some embodiments, the apparatus comprises a user equipment. According to some embodiments, the another node comprises a network node. According to some embodiments, the further node comprises a network node.

[0007] According to some embodiments, the another node and the further node may comprise different physical nodes, e.g., different TRPs. Thus, the embodiments may relate to, for example, two loops for supporting two Transmission Configuration Indicator States (TCIs), each of which may be associated with a different TRP. According to some embodiments, the another node and the further node may comprise the same physical node, with different "nodes" being represented by two TCIs of the same TRP. Thus, a node according to some embodiments may comprise a TCI beam of the TRP, and different nodes may comprise different TCI beams of the same TRP.

[0008] According to some embodiments, the received reference signal comprises a downlink signal. According to some embodiments, the received reference signal comprises a signal received from another node and / or from a further node. According to some embodiments, the evaluated indication of the predicted signal quality metric comprises an evaluated indication of a predicted uplink signal quality metric.

[0009] According to embodiments, conditional use of a timing advance loop, or timing advance loop, refers to an apparatus making a tentative alignment assumption at another or further node, using which the apparatus may test the timing advance loop as a different timing alignment, e.g., alignment target, when evaluating predicted signal quality metrics or when deriving or transmitting related information to another or further node, without actually performing timing alignment. Conditional use may be understood to mean hypothesized or tentative use of the loop.

[0010] According to some embodiments, the configuration for measuring the received reference signal includes: an indication of one or more signal quality metrics to be evaluated.

[0011] According to some embodiments, the one or more signal quality metrics to be evaluated include: an indication of interference at another node or a further node or an indication of signal spreading as a result of the conditional use of at least one timing advance loop.

[0012] According to some embodiments, the one or more signal quality metrics to be evaluated include: an indication of interference caused by timing deviations caused at another node or further nodes based on the conditional use of at least one timing advance loop.

[0013] According to some embodiments, the configuration for measuring the received reference signal includes: a threshold predicted quality metric.

[0014] According to some embodiments, the apparatus comprises: comparison means for comparing the evaluated indication of a predicted signal quality metric at the other or further node with a threshold predicted quality metric.

[0015] According to some embodiments, the transmitted information relating to the evaluated indication of the predicted signal quality metric at the another node and / or the further node includes: an indication of whether the predicted signal quality metric is above or below a threshold.

[0016] According to some embodiments, the apparatus comprises: receiving means for receiving, in response to transmitting information regarding an evaluated indication of a predicted signal quality metric at the another node and / or the further node, enablement of an additional timing advance loop to be applied in connection with communication with the another node and / or the further node.

[0017] According to some embodiments, the means comprises: at least one processor; and at least one memory containing computer program code, the at least one memory and the computer program code configured to cause implementation of the apparatus using the at least one processor.

[0018] According to various, but not necessarily all, example embodiments, there is provided a user equipment method that includes: indicating to another node that multiple timing advance loops are supported; receiving from the other node a configuration for measuring received reference signals from the other node; performing measurements on the received reference signals in accordance with the configuration; evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the other node or a further node based on use of a common timing advance loop; and transmitting information related to the evaluated indication of the predicted signal quality metric at at least one of the other node and the further node.

[0019] According to some embodiments, the another node comprises a network node. According to some embodiments, the further node comprises a network node. According to some embodiments, the received reference signal comprises a downlink signal. According to some embodiments, the received reference signal comprises a signal received from the another node and / or from a further node. According to some embodiments, the evaluated indication of the predicted signal quality metric comprises an evaluated indication of a predicted uplink signal quality metric.

[0020] According to some embodiments, the configuration for measuring the received reference signal includes: an indication of one or more signal quality metrics to be evaluated.

[0021] According to some embodiments, the one or more signal quality metrics to be evaluated include: an indication of interference at another node or a further node or an indication of signal spreading as a result of the conditional use of at least one timing advance loop.

[0022] According to some embodiments, the one or more signal quality metrics to be evaluated include: an indication of interference caused by timing deviations caused at another node or further nodes based on the conditional use of at least one timing advance loop.

[0023] According to some embodiments, the configuration for measuring the received reference signal includes: a threshold predicted quality metric.

[0024] According to some embodiments, the method includes: comparing the evaluated indication of the predicted signal quality metric at the other or further node to a threshold predicted quality metric.

[0025] According to some embodiments, the transmitted information relating to the evaluated indication of the predicted signal quality metric at the another node and / or the further node includes: an indication of whether the predicted signal quality metric is above or below a threshold.

[0026] According to some embodiments, the method includes: receiving, in response to transmitting information regarding an evaluated indication of a predicted signal quality metric at at least one of the another node and the further node, enablement of an additional timing advance loop to be applied in connection with communications with at least one of the another node or the further node.

[0027] According to various, but not necessarily all, example embodiments, provided is a computer program product that, when executed on a computer, is operable to perform the following methods: indicate to another node that multiple timing advance loops are supported; receive from the other node a configuration for measuring received reference signals from the other node; perform measurements on the received reference signals in accordance with the configuration; based on the measurements, evaluate an indication of a predicted signal quality metric associated with at least one of the other node or a further node based on use of a common timing advance loop; and transmit information related to the evaluated indication of the predicted signal quality metric at at least one of the other node and the further node.

[0028] A non-transitory computer-readable medium storing computer program code including instructions that, when executed by a processor, cause an apparatus to perform the following steps: indicating to another node that multiple timing advance loops are supported; receiving from the other node a configuration for measuring received reference signals from the other node; performing measurements on the received reference signals in accordance with the configuration; evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the other node or a further node based on use of a common timing advance loop; and transmitting information related to the evaluated indication of the predicted signal quality metric at at least one of the other node and the further node.

[0029] According to various, but not necessarily all, example embodiments, provided is an apparatus comprising: means for determining that multiple timing advance loops are supported by a node; means for transmitting to the node a configuration for measuring a received reference signal; and means for receiving from the node information regarding an evaluated indication of a predicted signal quality metric at at least one of another node or a further node.

[0030] According to some embodiments, the apparatus includes a network node. According to some embodiments, the node includes user equipment. According to some embodiments, the further node includes a network node. According to some embodiments, the received reference signal includes a downlink signal. According to some embodiments, the received reference signal includes a signal received at the user equipment from another node and / or from a further node. According to some embodiments, the evaluated indication of the predicted signal quality metric includes an evaluated indication of a predicted uplink signal quality metric.

[0031] According to some embodiments, the configuration for measuring the received signal includes: an indication of one or more signal quality metrics to be evaluated.

[0032] According to some embodiments, the one or more signal quality metrics to be evaluated include: an indication of interference or an indication of signal spreading at at least one of another node or a further node as a result of the conditional use of at least one timing advance loop.

[0033] According to some embodiments, the configuration for measuring the received reference signal includes: a threshold predicted quality metric.

[0034] According to some embodiments, the apparatus comprises: a decision means configured to compare information regarding an evaluated indication of a predicted signal quality metric at at least one of the another node and the further node with a threshold predicted quality metric to decide whether to enable an additional timing advance loop.

[0035] According to some embodiments, the apparatus comprises: assessment means configured to assess information relating to an evaluated indication of a predicted signal quality metric at at least one of the another node and the further node to assess whether a threshold predicted quality metric is met.

[0036] According to some embodiments, the apparatus comprises: means for transmitting enablement of at least one additional timing advance loop in response to a determination based on the received evaluated indication of a predicted signal quality metric at at least one of the another node and the further node.

[0037] According to some embodiments, the means comprises: at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code configured to cause, using the at least one processor, to cause implementation of the apparatus.

[0038] According to various, but not necessarily all, example embodiments, provided is a network node method that includes: determining that multiple timing advance loops are supported by the node; transmitting to the node a configuration for measuring received reference signals; and receiving from the node information regarding an evaluated indication of a predicted signal quality metric at at least one of another node or a further node.

[0039] According to some embodiments, the apparatus includes a network node. According to some embodiments, the node includes user equipment. According to some embodiments, the further node includes a network node. According to some embodiments, the received reference signal includes a downlink signal. According to some embodiments, the received reference signal includes a signal received at the user equipment from another node and / or from a further node. According to some embodiments, the evaluated indication of the predicted signal quality metric includes an evaluated indication of a predicted uplink signal quality metric.

[0040] According to some embodiments, the configuration for measuring the received signal includes: an indication of one or more signal quality metrics to be evaluated.

[0041] According to some embodiments, the one or more signal quality metrics to be evaluated include: an indication of interference or an indication of signal spreading at at least one of another node or a further node as a result of the conditional use of at least one timing advance loop.

[0042] According to some embodiments, the configuration for measuring the received reference signal includes: a threshold predicted quality metric.

[0043] According to some embodiments, the method includes: comparing information regarding an evaluated indication of a predicted signal quality metric at at least one of the another node and the further node to a threshold predicted quality metric to determine whether to enable an additional timing advance loop.

[0044] According to some embodiments, the method includes: assessing information relating to the evaluated indication of the predicted signal quality metric at at least one of the another node and the further node to assess whether a threshold predicted quality metric is met.

[0045] According to some embodiments, the method includes: transmitting at least one additional timing advance loop enablement in response to a determination based on the received evaluated indication of a predicted signal quality metric at at least one of the another node and the further node.

[0046] According to various, but not necessarily all, example embodiments, provided is a computer program product that, when executed by a computer, is operable to perform the following methods: determine that multiple timing advance loops are supported by a node; transmit to the node a configuration for measuring a received reference signal; and receive from the node information regarding an evaluated indication of a predicted signal quality metric at at least one of another node or a further node.

[0047] A non-transitory computer-readable medium storing computer program code including instructions that, when executed by a processor, cause an apparatus to perform the following steps: determining that multiple timing advance loops are supported by the node; transmitting a configuration to the node for measuring a received reference signal; and receiving information from the node regarding an evaluated indication of a predicted signal quality metric at at least one of another node or a further node.

[0048] According to various, but not necessarily all, example embodiments, there is provided an apparatus comprising: means for transmitting an indication to a network node that multiple timing advance loops are supported; means for receiving from the network node a configuration for measuring downlink reference signals; means for performing measurements on the downlink reference signals in accordance with the configuration; means for evaluating, based on the measurements, an indication of a predicted uplink signal quality metric at a further network node based on use of a common timing advance loop; and means for transmitting to the network node an indication of the evaluated indication of the predicted uplink signal quality metric at the further network node.

[0049] According to some example embodiments, the apparatus may include user equipment.

[0050] According to various, but not necessarily all, example embodiments, there is provided a user equipment method that includes: transmitting an indication to a network node that multiple timing advance loops are supported; receiving a configuration from the network node for measuring downlink reference signals; performing measurements on the downlink reference signals in accordance with the configuration; evaluating, based on the measurements, an indication of a predicted uplink signal quality metric at a further network node based on use of a common timing advance loop; and transmitting to the network node an indication of the evaluated indication of the predicted uplink signal quality metric at the further network node.

[0051] According to various, but not necessarily all, example embodiments, provided is an apparatus comprising: means for receiving an indication from a user equipment that multiple timing advance loops are supported by the user equipment; means for transmitting to the user equipment a configuration for measuring downlink reference signals; and means for receiving from the user equipment an evaluated indication of a predicted uplink signal quality metric at a further network node.

[0052] According to some example embodiments, the apparatus may include: a network node.

[0053] According to various, but not necessarily all, example embodiments, there is provided a network node method that includes: receiving an indication from a user equipment that multiple timing advance loops are supported by the user equipment; transmitting a configuration to the user equipment for measuring downlink reference signals; and receiving from the user equipment an evaluated indication of a predicted uplink signal quality metric at a further network node.

[0054] According to various, but not necessarily all, example embodiments, provided is a computer program product that, when executed on a computer, is operable to perform the following methods: send an indication to a network node that multiple timing advance loops are supported; receive a configuration from the network node for measuring downlink reference signals; perform measurements on the downlink reference signals in accordance with the configuration; evaluate, based on the measurements, an indication of a predicted uplink signal quality metric at a further network node based on use of a common timing advance loop; and send an indication to the network node of the evaluated indication of the predicted uplink signal quality metric at the further network node.

[0055] According to various, but not necessarily all, example embodiments, provided is a computer program product that, when executed on a computer, is operable to perform the following methods: receive an indication from a user equipment that multiple timing advance loops are supported by the user equipment; transmit a configuration to the user equipment for measuring downlink reference signals; and receive from the user equipment an evaluated indication of a predicted uplink signal quality metric at a further network node.

[0056] A non-transitory computer-readable medium storing computer program code comprising instructions that, when executed by a processor, cause an apparatus to perform the following steps: sending an indication to a network node that multiple timing advance loops are supported; receiving a configuration from the network node for measuring downlink reference signals; performing measurements on the downlink reference signals in accordance with the configuration; evaluating, based on the measurements, an indication of a predicted uplink signal quality metric at a further network node based on use of a common timing advance loop; and sending to the network node an indication of the evaluated indication of a predicted uplink signal quality metric at the further network node.

[0057] A non-transitory computer-readable medium storing computer program code comprising instructions that, when executed by a processor, cause an apparatus to perform the following steps: receive an indication from a user equipment that multiple timing advance loops are supported by the user equipment; send a configuration to the user equipment for measuring downlink reference signals; and receive from the user equipment an evaluated indication of a predicted uplink signal quality metric at a further network node.

[0058] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims where appropriate, and in combinations other than those explicitly set out in the claims.

[0059] Where a device feature is described as operable to provide a function, this is to be understood to include a device feature that provides that function or is adapted or configured to provide that function.

[0060] Some example embodiments will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0061] [Figure 1A] FIG. 1 is a diagram illustrating a general wireless communication system network architecture. [Figure 1B] FIG. 2 is a diagram illustrating a relationship between downlink frame timing and uplink frame timing. [Figure 2] FIG. 10 graphically illustrates the contribution of a UE transmitted signal to signal power depending on the arrival time at a receiving node. [Figure 3] 3A, 3B, 3C, and 3D are diagrams that graphically illustrate examples of estimated power delay profiles. [Figure 4] 4A, 4B, and 4C are diagrams illustrating the timing of uplink and downlink signals at both the UE and two TRPs when the UE implements a single Timing Advance (TA) value. [Figure 5]Figures 5A, 5B, 5C, 5D, and 5E are diagrams illustrating example power delay profiles (PDPs) from and to different TRPs depending on whether one or two timing advance loops are implemented by the UE. Figure 5F is a diagram schematically illustrating a UE configured to receive from two TRPs in an mTRP network. [Figure 6] FIG. 10 graphically illustrates an example of how a predicted UL quality metric (e.g., P-SIISCIR) for a UE operating using a single TA loop decreases as the time difference of arrival of the UE UL signal increases between two TRPs. [Figure 7] FIG. 1 is a signaling diagram illustrating signaling between a network and a user equipment according to two possible configurations. [Figure 8] FIG. 1 is a diagram illustrating schematically some components of a network including nodes according to some configurations. [Figure 9] 1A-1C are diagrams illustrating generally method steps performed according to some configurations. DETAILED DESCRIPTION OF THE INVENTION

[0062] Before discussing aspects in more detail, an overview of the context in which the aspects will be understood is first provided.

[0063] 1A schematically illustrates a general wireless communications system network architecture. While the configuration is described with respect to one possible network architecture, it should be understood that the principles of operation according to the configuration may be applied across a range of network architectures without undue burden. In particular, the configuration is described with respect to an access architecture based on Long Term Evolution Advanced (LTE-A) or new radio (NR), also known as fifth-generation (5G) network architecture, but the configuration is not considered limited to such architecture.

[0064] Examples of other architectures and systems include, for example, architectures including Universal Mobile Telecommunications System (UMTS) Radio Access Networks (UTRAN or E-UTRAN), Long Term Evolution Networks (LTE), Non-terrestrial Networks (NTN), Wireless Local Area Networks (WLAN or WiFi) networks, and the like.

[0065] 1A illustrates schematically some major components of an exemplary radio access network. Typically, the network includes multiple User Equipment (UE) devices 100.

[0066] The UE 100 typically includes a portable computing device that includes wireless mobile communication capabilities. UE devices include, but are not limited to, the following types of devices: mobile stations (cell phones), smartphones, personal digital assistants (PDAs), handsets, devices that use wireless modems (such as alarms or measurement devices), laptop and / or touchscreen computers, tablets, game consoles, notebooks, and multimedia devices. UE devices may include machine-type communication devices (MTC devices) and various devices capable of operating within an Internet of Things (IoT) network.

[0067] The UE is configured to be in wireless communication with one or more network access nodes 110. A network access node, e.g., a gNB, provides a radio frequency region of coverage called a cell. The UE communicates with the network access node using one or more communication channels within the cell. The wireless communication link from the UE to the network node is called the uplink (UL), and the wireless communication link from the network node to the UE is called the downlink (DL).

[0068] A communication system typically includes two or more network access nodes, which may also be configured to communicate with each other over links, either wired or wirelessly, forming the "network side" of the architecture. The network side nodes may include computing devices configured to control radio resources of the communication system. The network access nodes may be referred to as base stations (BSs), access points, or the like.

[0069] The network access node 110 typically includes or is coupled to a transceiver. From the network access node's transceiver, a connection is provided to an antenna unit that establishes a bidirectional (or duplex) radio link to the UE 100. The antenna unit may include multiple antennas or antenna elements. The network access node is also typically connected to a core network 120.

[0070] Different duplexing schemes result in different interference situations and different ways of predicting the channel of interference. For example, in a time division duplexing (TDD) scheme, the bidirectional channels, i.e., the uplink and downlink, are highly correlated within the channel coherence time. In a frequency division duplexing (FDD) scheme, the bidirectional channels are typically separated, e.g., such that only long-term information is similar in the uplink and downlink. Examples of such long-term information include: the dominant signal arrival direction or signal transmission direction. In TDD and similar duplexing schemes, the instantaneous channel is reciprocal, while in FDD systems, typically only long-term or statistical reciprocity is available.

[0071] It should be understood that assumed reciprocity characteristics of operation within the network can thus be used as support for estimation techniques. For example, it may be possible to make some assumptions at the UE based on measurements made at the UE. Configurations described in more detail below, for example, can use information derived from UE-based measurements in conjunction with assumed operation of the timing advance loop to "infer" likely signal interference information at a node receiving a transmission from the UE.

[0072] Some networks allow a UE to establish simultaneous connections to more than one network access node, or "Transmission and Reception Point" (TRP). In a multi-TRP scenario, the UE can connect to multiple transmission and reception points (TRPs). Beam management techniques are used when the UE forms an initial connection with the network, and ongoing management occurs while the UE is in the connected state. In the connected state, the operation of the transmit and receive beams can be improved. Beam management defines a set of functions to assist the UE in setting the parameters of the receive (Rx) beam and transmit (Tx) beam for downlink reception and uplink transmission, respectively.

[0073] Timing Advance Background When a UE is communicating with a TRP, the propagation delay for a radio frequency (RF) signal traveling the distance between the TRP and the UE and vice versa delays the signal in both the downlink (DL) and uplink (UL) directions. In order for the TRP to decode signals from multiple UEs, each with a different distance to the TRP and therefore a different propagation delay, a timing advance (TA) procedure is provided.

[0074] According to the TA procedure, each UE is required to advance its UL signal transmission so that it is received at the TRP at a specified time. That is, the transmission time of each UE is selected to achieve substantially simultaneous arrival at the TRP. All UEs in the TRP are then synchronized so that each gNB has a single Fast Fourier Transform (FFT) timing for all incoming signals from different UEs. In other words, different UEs have a shared target synchronization point. If the UEs do not have a shared synchronization point, inter-symbol interference occurs. If signals from multiple UEs are not received in alignment, multiple UL symbols will overlap. That is, without alignment, inter-user interference may occur.

[0075] Furthermore, the TA loop mechanism operates to attempt to ensure that the UL signal received at the TRP does not overlap with a subsequent DL transmission.

[0076] Interference can also occur within the network as intra-user or inter-user interference.

[0077] Different UEs connected to the same TRP apply dedicated TA values ​​for each UE, so that all signals arrive at the TRP synchronously and with minimum inter-symbol overlap.

[0078] The DL signals from the TRP arrive at different UEs at different time instances depending on different propagation delays.

[0079] FIG. 1B schematically illustrates the relationship between downlink frame timing and uplink frame timing, as well as an indication of how a timing advance offset operates. As shown in FIG. 1B, an offset 30 is applied to uplink frame 20 but not to downlink frame 10. The timing advance is a negative offset 30, typically applied at the UE, between the start of the received downlink subframe 10 and the transmitted uplink subframe 20. Such an offset at the UE is necessary to ensure that the downlink and uplink subframes are synchronized on the network side. Typically, the timing advance (TA) offset 30 is equal to twice the propagation delay determined to apply between the network side and the UE, assuming that the same propagation delay value determined in relation to the downlink also applies in the uplink direction.

[0080] Implementing timing advance allows UL signals from different UEs to the same TRP to be aligned in time to any desired resolution. In FR2 New Radio (NR) with 120 kHz subcarrier spacing (SCS), the cyclic prefix (CP) is 590 ns. The TA step size is 65.1 ns, so there are approximately 9 steps within the CP length. In a timing advance command sent in the Medium Access Control (MAC) Control Element (CE), the UE can be requested to change its UL timing by up to + / - 31 times the step size mentioned above. The length of the step size is the limit of the accuracy with which the gNB can time-align UL signals from one UE within the gNB CP receive window. In RAN4, 3GPP specifies the minimum synchronization in the case of carrier aggregation (CA) in intra-band contiguous, and the minimum synchronization is 260 ns.

[0081] UL quality assessment in mTRP scenarios when channel delay is outside the CP Many different block transmission methods exist, such as OFDM, OFDMA, multicarrier CDMA, and precoded OFDM, each of which may involve a transmission method that decouples subsequently transmitted blocks from one another. Decoupling is achieved using a cyclic prefix or zero padding. For example, in an OFDM-modulated signal, each OFDM symbol consists of a data sequence preceded in time by a cyclic prefix (CP). The cyclic prefix is ​​a copy of the last part of the FFT-modulated data sequence and is designed to extend the range of multipath delays over which the subcarriers of an OFDM symbol can remain orthogonal. In other words, if all multipath delays of the channel are within the CP, the receiver can maintain orthogonality between the subcarriers as long as proper synchronization is performed.

[0082] In general, if the delays are all captured within the CP length, the receiver will see perfect orthogonality between consecutive OFDM symbols and between subcarriers of the same OFDM symbol, leading to no signal degradation. However, if any multipath delays are larger than the CP length, the received signal performance will suffer from both inter-symbol interference and inter-subcarrier interference.

[0083] An example of theoretical background for a good analytical description of the amount of interference versus signal power in a CP-OFDM system is: [1] H. Steendam, M. Moenclaey, "Analysis and Optimization of the Performance of OFDM on Frequency-Selective Time-Selective Fading Channels," IEEE Trans.Commun.vol.47, pp.1811-1819, December 1999, and [2] M. Batariere, K. Braum, T. P. Krauss, "Cyclic Prefix Length Analysis for 4G OFDM Systems," VTC'04, Los Angeles, USA, September 2004, and can be expressed as the Signal to Interference and Noise Ratio (SINR).

[0084] From [1], the following expression for SINR can be found:

number

[0085] In this document, SI ISCI R is: SI ISCI R=SINR Here, the desired signal power (P s )teeth:

number

[0086] In addition, the interference power (P i )teeth:

number

[0087] Figure 2 graphically illustrates the contribution of a UE transmitted signal to signal power depending on the arrival time at the receiving node. It can be seen that whether a signal contributes to the received signal, or whether it is considered interference, depends on whether it is received at the receiving node before or after one CP period expiration. A weighting function C(τ) is used to weight the individual delay taps according to their position within the OFDM symbol.

[0088] If all delay taps (τ1, τ2, τ3) are within the CP (between 0 and Δ in Figure 2) at the receiving node and have a weight of 1, they will s ) and contributes only to the interference power (P i ) does not contribute to

[0089] When the delay is between CP (ie, >Δ) and the full OFDM symbol length (NT) (eg, τ4, τ5, τ6), the weighting gradually changes from signal power to interference power.

[0090] P i The above equation for is referred to herein as Inter Symbol and Carrier Interference (ISCI), and P-ISCI is the Predicted Inter Symbol and Carrier Interference (P-ISCI). It is a calculation of the inter symbol and inter carrier interference power caused by having delay taps outside the CP length.

[0091] Another measure used herein is: Mean Delay Spread (DS mean :Average Delay Spread), which is:

number

number

[0092]

number

[0093] 3A through 3D graphically illustrate four examples of different estimated power delay profiles and their arrival time results inside or outside a cyclic prefix (CP) length of 50. The table below presents the associated calculated prediction quality for each example.

[0094] [Table 1]

[0095] Each PDP in FIG. 3 includes four delay taps with the following characteristics: Figure 3A: All delay taps are within the CP length, no interference, P-SI ISCI R=40dB (maximum hardware capability). Figure 3B: One delay tap at -6 dB is outside the CP at 1.6 us; P-SI ISCI R=12.4dB. Figure 3C: One outer delay tap of the CP is turned down to -12 dB; P-SI ISCI R=18.6dB. FIG. 3D: A single delay tap outside the CP has a lower delay 1 us and therefore a lower P-SI. ISCI R=22.4dB.

[0096] In all examples in Figures 3A through 3D, the first delay is assumed to be located at 1 / 3 CP. This means that it is assumed that the gNB aligns the timing of the UL signal from the UE (e.g., by using a timing advance procedure) so that the first reflection is located 1 / 3 of the way within the CP at the gNB receiver. UL timing alignment is controlled by the gNB using a timing advance command (TAC). This 1 / 3 is introduced to allow a degree of robustness in the receiver against timing errors related to synchronization, and it is a common value used in 3GPP. However, the actual synchronization point within the gNB hardware is gNB implementation specific.

[0097] The interference considered here is inter-symbol and inter-subcarrier interference caused by signal taps received outside the CP.

[0098] Therefore, the importance of proper application of timing advance by UEs within a network can be appreciated.

[0099] Aspects described in more detail below seek to address the consequences of a multi-timing advance (multi-TA) feature to be provided within a wireless communications network. When a UE has the capability to use two uplink (UL) streams from two panels for simultaneous transmission to either one or two received TRPs, it may be desirable to enhance multi-TRP operation, particularly within the FR2 frequency range.

[0100] Multi-TRP (mTRP) is a key feature for beam management. 3GPP Rel-16 supports mTRP for simultaneous physical downlink shared channels (PDSCHs) using a single downlink control information (DCI) (for both frequency division multiplexing (FDM) and space division multiplexing (SDM)). Rel-17 supports mTRP for physical uplink control channels (PUCCHs) and physical uplink shared channels (PUSCHs) using time division multiplexing (TDM). Rel-18 addresses simultaneous PUCCHs and PUSCHs as well as UE multi-panel transmissions. In this context, timing advance (TA) is an issue that needs to be addressed.

[0101] It is possible to allow two parallel timing advance values ​​for mTRP multi-DCI configured UEs.

[0102] UL timing in mTRP scenarios It is possible that a UE may have the capability to use either a single TA loop or multiple TA loops.

[0103] 4 illustrates a UE 100 in communication with two TRPs 200. Each TRP is a different radio propagation delay from the UE 100. TRP1 is a propagation delay D1 away from the UE 100, and TRP2 is a propagation delay D2 away from the UE 100.

[0104] 4A to 4C schematically illustrate the timing of uplink and downlink signals in both the UE and two TRPs when the UE 100 implements a single TA value (i.e., 1TA) for the two TRPs, TRP1 and TRP2, with each TRP 200 having its own reference time.

[0105] Figure 4A shows the timing of two DL signals from two TRPs when they are transmitted simultaneously from the two TRPs. The implementation shown in Figure 4A is for a network using FR2, which operates within the Time Division Duplexing (TDD) band and therefore all TRPs are assumed to be time synchronized.

[0106] 4B shows the timing at the UE, where two DL signals from two separate TRPs are likely to be received at different times due to the different distances and radio propagation characteristics between the UE and each of the two TRPs. D1 is the (one-way) propagation delay between TRP1 and the UE, and D2 is the (one-way) propagation delay between TRP2 and the UE.

[0107] 4C illustrates that UE 100 is configured such that the UL transmission time is advanced relative to the reception time by a single timing advance TA1. The UE UL signal for TRP1 is transmitted 2×D1=TA1 time before reception of the signal from TRP1, so that at TRP1, the UE UL signal is received substantially aligned with the DL signal.

[0108] If the UE is configured to operate using a single TA loop, the UE UL signal for TRP2 is also transmitted 2×D1(TA1) time before the reception of the signal from TRP2, and therefore, as illustrated in the figure, the UL signal to TRP2 is received at TRP2 with a time difference of (2×D2-2×D1), thus introducing a lack of synchronization at TRP2 relative to TRP1.

[0109] In the example shown in Figure 4, the timing of the transmitted signals from the two TRPs is synchronized. The timing of the reception of the DL signal at the UE depends on the propagation delay. Relative to the UE DL reception time, the UL signal is transmitted by the UE using a single TA loop, i.e., a timing advance that is time-shifted by a TA value for one TRP-specific DL UE reception, corresponding to D1 for a single TA aligned with TRP1, for example.

[0110] Numerical example: Assume that the distance between the UE and TRP1 is 30 m, and the distance between the UE and TRP2 is 80 m.

[0111] The delay values ​​D1 and D2 are: D1=100 ns and D2=267 ns. In this example, the UL signal for TRP2 will be received at TRP2 with a delay given by: 2×D2-2×D1=2×267ns-2×100ns=334ns

[0112] It can be seen from Figure 4 that a single TA loop in an mTRP network may not be suitable for efficient UE operation. To improve the overall operation of the mTRP network, the UE may be provided with multi-TA loop capability. Such multi-TA loop capability may be used, for example, in conjunction with FR2.

[0113] As presented below, for a given channel PDP, it is possible to estimate or calculate the contribution of one or more signals, whether they are received inside or outside the CP, as well as the level of inter-symbol and inter-subcarrier interference from signals received outside the CP length. This signal quality is expressed in terms of SINR for each channel instance. In general, the more channel delay power located outside the CP length, the lower the SINR the receiver will achieve. Nevertheless, a simple calculation based solely on the CP length may not be representative of whether a UE or network would benefit from implementing multi-TA capabilities.

[0114] Context Overview The following different metrics are introduced, all of which describe the Power Delay Profile (PDP): SI ISCI R: Signal-to-Interference Ratio, which is the interference caused by inter-symbol and inter-carrier (ISCI) where the interference is due to PDP taps outside the CP length. ISCI: Inter-Symbol and Inter-Carrier Interference. A measure of the power of the inter-symbol and inter-carrier interference due to PDP taps outside the CP length. DS mean : Specifies the average delay of different taps in the power delay profile (PDP). DS rms : Specifies the spread of different taps in the power delay profile (PDP).

[0115] In this specification, P-SI ISCI R, P-ISCI, P-DS mean , and P-DS rms is used to refer to the UE predicted versions of the different metrics mentioned above.

[0116] 5A to 5E illustrate example power delay profiles (PDPs) from and to different TRPs depending on whether one or two timing advance loops are implemented in the scenario illustrated schematically in FIG. 5F.

[0117] 5F illustrates a UE 100 in communication with two TRPs 200. Each TRP is a different radio propagation delay from the UE 100. TRP1 is a propagation delay D1 away from the UE 100, and TRP2 is a propagation delay D2 away from the UE 100.

[0118] 5A schematically illustrates an example of a UE estimated power delay profile (PDP) for an incoming downlink (DL) signal from TRP1. The first reflection is aligned with the 1 / 3 CP.

[0119] 5B schematically illustrates an example of a UE estimated PDP for an incoming downlink signal from TRP2. The first reflection is again aligned with the 1 / 3 CP.

[0120] 5C schematically illustrates an example of TRP1 estimated PDP based on an uplink signal transmitted by a UE. The timing advance TA of UE 100 is "set" by the closest TRP, specifically TRP1, and the UE is configured to transmit uplink with a timing advance (TA) of 2×D1 such that the first reflection received at TRP1 from UE 100 is approximately aligned with ⅓ CP.

[0121] 5D schematically illustrates an example of a TRP2 estimated PDP for a UL signal from UE 100 when the UE is configured to apply one TA loop. Because the single TA loop is aligned to TRP1 and because TRP1 and TRP2 are at different distances from the UE and therefore have different radio propagation delays, the first reflection at TRP2 is delayed by the distance difference 2 (D2-D1) from the UE to the two TRPs. The result is that part of the PDP may be subject to a delay greater than the CP length and thus potentially interfere / corrupt data symbols. In the example shown in FIG. 5D, one delay tap is likely to be received at TRP2 from UE 100 within a critical area where inter-symbol and inter-carrier interference will be generated.

[0122] 5E schematically illustrates an example of a TRP2 estimated PDP for a UL signal from a UE when the UE is configured to apply two TA loops. Thus, the UE 100 may be configured to use a 2×D2 TA in communication with TRP2. Because two TA loops are enabled, the UE's implementation of the second TA loop for TRP2 may help ensure that the first delay tap in the PDP at TRP2 is maintained around ⅓ CP.

[0123] The configuration recognizes that, while being outside the CP length as shown in FIG. 5D is an indicator of whether some inter-symbol and inter-carrier interference may be generated, the functional significance of that interference may vary. In particular, being outside the CP may cause minimal interference depending on how far the UE uplink signal falls outside the CP. Similarly, depending on hardware capabilities, the TRP may be able to tolerate some interference even if the UE uplink signal falls outside the CP. In such scenarios, implementing multiple TA configurations may not be beneficial to the overall network efficiency for the UE and the network.

[0124] In other words, the simple metric of being received inside or outside the CP is not a sufficiently accurate metric to determine whether a UE should be a user of a one or two TA loop configuration. In fact, even when a signal is received outside the CP, it can still be decoded by the gNB, but the SINR will be degraded. The configurations described herein recognize that it may be useful to implement different metrics to facilitate assessment of whether it may be advantageous to implement a single or multiple loop TA loop configuration for overall network operation.

[0125] Before discussing example embodiments in more detail, an overview of the architecture will first be provided.

[0126] The configuration may provide an apparatus, e.g., user equipment, comprising: means for indicating to another node that multiple timing advance loops are supported; means for receiving from the other node a configuration for measuring received reference signals from the other node; means for performing measurements on the received reference signals in accordance with the configuration; means for evaluating an indication of a predicted signal quality metric associated with at least one of the other node or a further network node based on the conditional use of at least one timing advance loop based on the measurements; and means for transmitting information related to the evaluated indication of the predicted signal quality metric at at least one of the other node and the further network node.

[0127] The another node may include a network node, which may be a primary or serving network node with which the user equipment is communicating. The further node may also include a network node, which may be a different network node with which the user equipment is communicating. The received reference signal may include a downlink signal. The received reference signal may include a signal received from another node and / or from a further node. The evaluated indication of the predicted signal quality metric may include an evaluated indication of a predicted uplink signal quality metric.

[0128] On the network side, the configuration may provide an apparatus, e.g., a network node, comprising: means for determining that multiple timing advance loops are supported by the node; means for transmitting to the node a configuration for measuring received reference signals; and means for receiving from the node information regarding an evaluated indication of a predicted signal quality metric at at least one of another node or a further network node.

[0129] The node may include a user equipment. The further network node may include a network node. The received reference signal may include a downlink signal. The received reference signal may include a downlink signal received at the user equipment from another node and / or from a further node. The evaluated indication of a predicted signal quality metric may include an evaluated indication of a predicted uplink signal quality metric.

[0130] The described configurations relate to enhancements to the mechanism that determines whether a single or multiple TA loops should be configured to support m-TRP activity.

[0131] The configuration recognizes that the UE may be configurable to support calculation of an estimate of a predicted UL quality metric for simultaneous UL transmissions, e.g., in a group of transmission configuration (TCI) states. According to one example, the TCI states may be identified by their corresponding downlink reference signals (DL RSs), and the predicted UL quality may be based on a calculation based on factors including, e.g., UL time alignment to CP length for a single TA loop. The output of such a calculation may be compared against a threshold UL quality metric, e.g., by the UE or by the network. Such a comparison against a threshold may be used as a criterion against which the network or UE may assess whether a single TA loop or multiple TA loops are most suitable for implementation by the UE in the network. For example, the configuration may provide a threshold value for the predicted UL quality against which the UE or network may assess whether a single TA loop implementation or multiple TA loop implementation provides efficient operation.

[0132] According to the described configuration, the UE may be configured to evaluate, measure, or report one of many parameters that enable calculation of a predicted UL quality in the TRP. The calculation of the predicted UL quality may include calculation of one or more quality metrics. The calculated quality metric may include, for example: predicted symbol and inter-carrier interference (P-ISCI), where ISCI is the inter-symbol plus inter-carrier interference power caused by the UL timing offset in the TRP when using one TA loop. Alternatively, the calculated quality metric may include predicted SI ISCI R, where the interference power I ISCI is solely due to ISCI. ISCI R is defined as the signal-to-interference ratio when considering the UL signal deviation at the TRP caused by using one TA loop.

[0133] The described configurations may utilize one or a combination of the following metrics and definitions as support for the calculation of one or more predicted UL quality metrics: P-ISCI (Predicted Symbol Inter-Subcarrier Interference) P-SI ISCI R (expected signal-to-interference (inter-symbol and inter-carrier) ratio) P-DSrms (Predicted Delay Spread RMS) P-DSmean (Predicted Delay Spread Mean)

[0134] The configuration recognizes that the UE may be configured to measure, report, or assess one or more operational characteristics of the network, which may be used to calculate, estimate, or predict one or more UL quality metrics, which may be assessed, calculated, or estimated for a group of TCI conditions.

[0135] Depending on the configuration, the UE may be configured to explicitly assess or calculate a UL quality metric and then report it to the network, or may report it implicitly to the network by indicating a preference for one or more TA loops, or the UE may report one or more measured, reported, or assessed operating characteristics of the network related to downlink reception, so that the network itself may be configured to assess or calculate a predicted UL quality metric associated with the UE, which may then be used to determine whether the UE is a candidate for implementation of one or more TA loops.

[0136] The configuration recognizes that assessment of the predicted UL quality at the TRP may be used to assist the gNB in ​​selecting, for example, between one or two TA loops in relation to the UE. The calculated UL quality metric may represent the cost in SINR of decoding signal taps that arrive at the TRP from the UE outside the CP length due to the implementation at the UE of a single TA loop.

[0137] As an example, the predicted UL quality (e.g., P-SI) for one TA loop ISCI If it is calculated and determined that R) is sufficient to allow successful decoding of the signal by the gNB, then use of a single TA loop may be selected or maintained. Alternatively, if it is calculated that the estimated UL quality does not meet a sufficient threshold, the gNB may be operable to determine to use, for example, two TA loops. In some configurations, if the estimated UL signal quality at the TRP is calculated to be insufficient and does not meet a pre-defined threshold, the UE may be configured to indicate a preference for implementing operation using two TA loops.

[0138] According to the configuration, the estimated UL signal quality at the TRP is based on measurements and parameters determinable at the UE. For example, the UE may be configured to calculate an estimate of the UL quality at the TRP from the measured DL RS. In the estimated UL SINR, the signal estimate may be based on reciprocity, and the interference estimate may consider only inter-symbol interference from taps detected after the end of the CP length at the TRP of interest. Neighbor cell interference experienced at the gNB may be handled directly by the gNB and, according to the configuration, is largely unrelated to and independent of one or two TA loop decisions.

[0139] The configuration recognizes that measurements made at the UE can be utilized to make an estimate of a predicted UL signal quality metric in the TRP. Such an estimate or prediction of UL signal quality can, in some implementations, enable the UE to assess and indicate directly to the network whether the amount of signal power received outside the CP length for a given propagation delay is critical for UL mTRP transmission, and thus support the decision-making process of whether a capable UE can benefit from, for example, implementing a second TA loop.

[0140] Figure 6 shows the predicted UL quality metric (e.g., P-SI) for a UE operating using a single TA loop as the time difference of arrival of the UE UL signal increases between two TRPs. ISCI Here is a graphical example of how R decreases:

[0141] According to the described configuration, a predicted UL quality metric value is calculated. Figure 6 generally illustrates the degradation of the predicted UL quality metric as the propagation delay difference between the UE and the TRP increases. The prediction can be calculated directly by the UE and reported explicitly or implicitly to the network.

[0142] According to the described configuration, the time difference of arrival can be calculated by the UE, for example, using the DL RS for each TCI state. Reciprocity and beam correspondence in the downlink / uplink configuration is assumed, for example, in a TDD FR2 system. As an example, the time difference between signals received from different TRPs can be calculated by the UE based on measurements from the first tap to the first tap of each received DL RS for each TCI state.

[0143] Figure 6 shows a horizontal "threshold" line representing a predicted UL quality metric that indicates when transitioning between single or multiple loop TAs may be beneficial to the operation of a UE within a network. When the predicted UL quality metric is above the threshold, a single TA loop implemented by the UE is likely sufficient to ensure that the UE can successfully transmit to, for example, two TRPs with negligible ISCI. Conversely, when the predicted UL quality metric is below the threshold, it may be beneficial for the UE to need to be configured with two TA loops so that two TRPs can successfully receive transmissions made by the UE.

[0144] While assessing whether the radio propagation delay between the UE and the TRP, together with the value of the single TA implemented by the UE for the CP length, provides one measure by which it is possible to determine whether there is a requirement to implement further TA loops, the configurations described herein recognize that the transition point can be more accurately assessed if the impact of falling outside the CP length and the capabilities of the network nodes involved in the communication can be taken into account.

[0145] Therefore, the described configuration introduces the implementation of a predicted uplink quality metric threshold and related signaling. According to the configuration, a tolerance level (threshold) associated with the predicted UL quality metric for the implementation of a single TA loop in the UE can be determined, for example, by the gNB. The threshold can be signaled to the UE. Alternatively, the threshold can be selected and specified as a UE requirement.

[0146] In summary, the configuration provides that, according to some implementations, the UE is configured to support the introduction of predicted uplink signal quality thresholds against which a decision as to whether it may be advantageous to implement more than a single TA loop can be assessed. The thresholds may be introduced into network operation in various ways, including, for example, using: RRC configuration from the network; dynamic indications from the network, e.g., MAC or DCI; pre-defined values ​​in specification documents; or UE-selected values ​​reported to the network.

[0147] The configuration may provide an implementation in which a UE may be configured to calculate a predicted UL quality metric for m-TRP operation when the UE operates in a single TA loop. The UE may be configured to perform such calculations, for example, for a TRP group for simultaneous UL transmissions. The calculation of the predicted UL signal quality metric may be based, for example, on one or more characteristics of operation measurable at the UE. Such characteristics may include, for example, measurements from a Transmission Configuration Indicator (TCI) or a Downlink Reference Signal (DL RS), such as a Synchronization Signal Block (SSB) or a Channel Status Information Reference Signal (CSI-RS).

[0148] The configuration may provide an implementation in which the UE may be configured to report the calculated predicted UL quality metric to the network. The reporting may be an explicit report of the calculated value, e.g., the UE may be configured to report the predicted UL quality metric. Alternatively, the UE may be configured to implicitly report the predicted UL quality metric, e.g., by indicating whether the calculated value exceeds a threshold or in the form of part of a TA loop indication (single loop or two or more loops) for a group of TCI conditions.

[0149] In other words, the configuration may provide an implementation according to which the UE may be configured to directly indicate the calculated predicted UL quality metric to the gNB. Alternatively, the UE may be configured to compare the calculated predicted UL quality metric with a threshold. Based on the comparison, the UE may be configured to indicate a preference for operation using, for example, one or two TA loops from the gNB accordingly. The calculated predicted UL quality metric may be used, for example, to provide information about each TCI combination, allowing an assessment to be made as to whether the UE is better suited to use a single TA loop or two or more TA loops.

[0150] Functionally, the predicted UL quality metric represents an indication of the UL quality that the gNB can use to predict whether the UE will use a single TA loop when considering likely interference, e.g., inter-symbol and / or inter-subcarrier interference (i.e., ISCI) caused by UL time offset.

[0151] In configuration implementations in which an acceptable (threshold) level of predicted UL quality metric is determined or selected by the gNB, the gNB may be configured to make such determination or selection based on a range of factors. Such factors may include, for example: use case; type of data; QoS; hardware capabilities, or the like. Depending on the configuration implementation, and as described in more detail below, the network may either operate to compare the UE-reported predicted UL quality metric with a determined or selected threshold, or to configure the UE to compare the calculated UL quality metric with a selected or determined UL quality threshold and report the results of such comparison.

[0152] Figure 7 is a signaling diagram illustrating signaling between a network 200 and a user equipment 100 according to two possible configurations. As shown in Figure 7, information may be provided to assess whether a user equipment may operate more efficiently under a single TA loop implementation or under multiple TA loop implementations within the network. Such information may be provided, for example, to support a decision as shown in the two implementations schematically represented in Figure 7.

[0153] Option A According to a first implementation shown in FIG. 7, the network node 200, e.g., a gNB, receives a reported predicted UL quality metric (e.g., P-SI) from the UE. ISCI R) The network node 200 is configured to use the reported predicted UL quality metrics from the UE 100 to assess whether the UE should operate using one TA loop or two TA loops.

[0154] Option B According to a second implementation, as shown in FIG. 7, a UE 100 operating in a network is configured to determine a UL quality metric threshold. Accordingly, a UE 100 operating according to such an implementation may be configured to compare the determined UL quality metric threshold with a calculated UE predicted UL quality metric. If the calculated predicted UL quality metric is within the determined UL quality threshold, the UE may be configured to report that operating using a single TA loop is sufficient. If the calculated predicted UL quality metric is not within the determined UL quality threshold, the UE may be configured to report that a single TA loop is not sufficient and that, for example, operating using two TA loops may improve the likelihood that an uplink transmission made by the UE will be successfully received at a receiving mTRP node.

[0155] Figure 7 illustrates implementation options A and B generally described above in the form of a signaling flow diagram. Figure 7 illustrates signaling between a UE 100 and a network node 200, e.g., a gNB. In the illustrated example implementation, new information is appended to an existing message.

[0156] An implementation according to Option A is shown on the left side of Figure 7 and shows a signaling flow according to which the UE is requested to report the calculated predicted UL quality metric to a network node, e.g., a gNB, and the network node is configured to make a final decision to configure one or two TA loops in relation to the UE based on the reported predicted UL quality metric.

[0157] An implementation according to Option B is shown on the right side of Figure 7 and illustrates a signaling flow according to which the UE is configured to have direct knowledge of the UL quality metric thresholds. Direct knowledge of the thresholds to be applied in conjunction with a network node, e.g., a TRP, may enable the UE to compare its calculated predicted UL signal quality metrics with the known thresholds and make an assessment as to whether the implementation of one TA loop or two TA loops may be beneficial for the UE's operation within the network. The UE may be configured to report the assessment back to the network node, e.g., a gNB.

[0158] As shown in Figure 7, the following signaling steps may take place: 700A: The UE is configured to indicate to the network, for example using a UE capability message, that the UE supports UL quality grouping of TCIs. 700B: In response to learning the UE capabilities, the network may be configured to provide an indication of a downlink reference signal (DL RS) to the UE for measurement and reporting for downlink and / or uplink beam selection.

[0159] The UE is configured by the network, for example, by a gNB of the network, to perform predicted UL signal quality metric reporting as further detailed below.

[0160] Option A 700C: According to Option A, the UE is configured by the gNB to report back one or more important parameters, and based on this parameter, the gNB is configured to select whether to use one TA loop or two TA loops in relation to the UE. The configuration message from the network to the UE may, according to some implementations, include an indication of a gNB Sync Point (which is the gNB's position within the CP of the first delay). As previously mentioned, the Sync Point may be gNB implementation specific and therefore unknown to the UE unless communicated directly to the UE.

[0161] Option B 700D: According to option B, the UE is configured by the gNB such that the UE is further provided with an UL quality metric threshold parameter that supports implementations according to which the UE provides some assistance in relation to assessing whether the selection of one TA loop or two TA loops is suitable to support the operation of the UE in the network. In the example implementation shown in FIG. 7, the UE configuration parameters include thresholds for predicted interference thresholds, e.g., P-ISCI and P-SI. ISCI R. Again, the configuration signaling may include an indication of the gNB UL synchronization point to assist the UE in UL quality estimation.

[0162] The UE performs predicted UL signal quality metric reporting as described in further detail below.

[0163] The UE is configured to calculate a prediction of what a TRP-estimated UL PDP (e.g., an estimated UL PDP such as that shown in FIG. 5D) will look like. The UE may be configured to calculate a predicted UL signal quality metric based on the estimated UL PDP. The predicted UL signal quality metric at the TRP takes into account interference due to deviations in UL TRP reception due to the UE's implementation of a single TA loop. Such a single TA loop may result in delay taps at the TRP not falling within the CP length.

[0164] Predicted UL quality metrics are: P-ISCI (Predicted Symbol and Inter-Carrier Interference); P-SI ISCI R (predicted signal-to-interference-and-noise ratio); or the like, and indications thereof. Alternatively, the predicted UL signal quality metric may include a predicted delay spread.

[0165] Option A 700E: A UE operating according to an implementation of Option A is configured to return one or more of the predicted quality measures to the network to assist the gNB in ​​assessing whether the UE is a candidate for using one TA loop or two TA loops.

[0166] Option B 700F: A UE operating according to an implementation of Option B is configured with knowledge of one or more UL quality metric thresholds. The UE is configured to compare a calculated predicted UL quality metric with the known threshold. If the calculated predicted UL quality is within (better than) the UL quality threshold configured by the gNB, the UE is configured to assess that use of a single TA loop is sufficient and return an indication of that assessment to the network. Similarly, if the calculated predicted UL quality is outside (worse than) the UL quality threshold configured by the gNB, the UE is configured to assess that use of a single TA loop is insufficient and return an indication of that assessment to the network. For example, if the predicted UL SINR is higher than the configured UL quality threshold for SINR, the UE assesses that use of a single TA loop is sufficient, and vice versa.

[0167] The UE assessment of step 700E (option A) or 700F (option B) is provided to the gNB using appropriate messaging.

[0168] Option A 700G: A UE operating according to the implementation of Option A is configured to report via appropriate signaling to the network gNB, the report including one or more indications of the predicted UL quality metric parameters estimated in step 700E. By way of example, the UE may be configured to report an estimated interference level, e.g., P-SINR or P-ISCI.

[0169] Option B 700H: A UE operating according to an implementation of Option B is configured to report or signal to the network, e.g., a gNB, the results of the assessment made by the UE in step 700F. According to some implementations, for each downlink reference signal (DL RS) combination configured as a result of step 700B, the UE may be configured to send an indication to the network regarding, for each combination, whether a single TA loop is sufficient or whether additional TA loops may support more efficient network operation. A UE according to some configurations is configured to assess each combination according to an appropriately configured UL quality threshold for each combination.

[0170] 700J: The configuration may provide that the gNB can configure the UE to operate using the second TA loop if it determines that such a configuration is desirable for network operation. Depending on the implementation, such a determination may be based on (i) an explicit value of the predicted UL signal quality metric returned to the gNB in ​​step 700G (option A), or (ii) an implicit indication of the predicted UL signal quality metric returned to the gNB in ​​step 700H based on a comparison of the explicit value of the predicted UL signal quality metric with a threshold value (option B).

[0171] To support the methodology illustrated in FIG. 7, the configuration provides a mechanism for the UE to indicate to the network whether it supports UL quality reporting (FIG. 7 step 700A). Such an indication can be provided by the UE in various ways. One implementation provides for adding parameters to the existing UE-NR-Capabilities information element. Such an information element is a message sent by the UE to the network, e.g., a gNB, when requested. This message typically includes several parameters describing the UE's capabilities.

[0172] As one example, the new parameter added to the existing IE may have the following form: { mTRP-UL-Quality-Grouping ENUMERATED{supported} }

[0173] Such an implementation means that a flag (Boolean) can be included in the information element to indicate that the UE supports the new feature: mTRP-UL-Quality-Grouping. Such an IE can be added to the UE capability report as specified in the IE UE-NR-Capability. It should be understood that this definition is an example and other names and data types can be specified.

[0174] To support the methodology illustrated in Figure 7, the configuration provides appropriate signaling from the network to configure the UE to report predicted UL signal quality metrics (Figure 7, steps 700C and 700D). That signaling configures the capable UE to: (i) to report one or more predicted UL signal quality parameters to the network (as in Option A of Figure 7), or (ii) Configure it to use the configured UL signal quality parameters (as in option B of Figure 7) to make an assessment of whether one TA loop or two TA loops appear to be more efficient.

[0175] In support of Option A of FIG. 7, the Information Element (IE) sent from the gNB to the UE may include one, a combination, or all of the parameters shown below: RequestPredictedULParameters::=SEQUENCE{ report-P-SIISCIR ENUMERATED{true}OPTIONAL, report-P-ISCI ENUMERATED{true}OPTIONAL, report-P-DSmean ENUMERATED{true}OPTIONAL, report-P-DSrms ENUMERATED{true}OPTIONAL }

[0176] By sending such information elements to the UE, the gNB may configure the UE to estimate and report back any one or more of the different predicted UL signal quality estimates. For example, according to some configurations, a network node, e.g., a gNB, may request that the UE estimate the P-ISCI and report it back to the gNB, or do the same for each parameter relevant to the predicted uplink signal quality.

[0177] In support of Option B shown in FIG. 7, messaging from the network to a capable UE may include an indication of one or more conditions to assist in determining whether the UE is a candidate for use of a single timing advance loop.

[0178] For example, in the message "RequiredFor1TAPredictedULParameters," the gNB may indicate one or more required UL quality parameters that must be satisfied by the corresponding UE-estimated predicted UL quality for the UE to "select" or indicate a preference for operation using a single TA loop. If any of the required parameters are not satisfied, the UE should "select" or indicate a preference for operation using two TA loops for mTRP transmission. For example, an information element (IE) to indicate the requested range for a UE using a single TA loop may be communicated to the UE using messaging such as: RequiredFor1TAPredictedULParameters::=SEQUENCE{ Requested-P-SIISCIR P-SIISCIR-Range OPTIONAL, Requested-P-ISCI P-ISCI-Range OPTIONAL, Requested-P-DSmean P-DSmean-Range OPTIONAL, Requested-P-DSrms P-DSrms-Range OPTIONAL }

[0179] To support the methodology illustrated in Figure 7, the configuration provides appropriate signaling from the UE to report predicted UL signal quality metrics back to the gNB. The UE may, for example, be configured to report UE predicted UL quality parameters (Figure 7, step 700G). The reported parameters may be those requested in step 700C in the message "RequestPredictedULParameters."

[0180] An information element (IE) for UE UL quality reporting may be defined, for example, as follows: ReportPredictedULParameters::=SEQUENCE{ P-SIISCIR P-SIISCIR-Range OPTIONAL, P-ISCI P-ISCI-Range OPTIONAL, P-DSmean P-DSmean-Range OPTIONAL, P-DSrms P-DSrms-Range OPTIONAL }

[0181] Here, each predicted UL quality metric may optionally be included in an IE that is reported to the network. Depending on the configuration, the report may be sent to the network, e.g., a gNB, and may be used by the gNB to assess, for example, whether one TA loop or two TA loops are appropriate for use with a particular mTRP combination.

[0182] As an example of the specification of ranges for different UL quality parameters, P-SIISCIR-Range may for example take over or be similar to the specification of SINR (from 38.331 3GPP) as shown below: --ASN1START --TAG-SINR-RANGE-START SINR-RANGE::=INTEGER(0..127) --TAG-SINR-RANGE-STOP --ASN1STOP Here, the ranges are further explained with mapping to values ​​in dB to 38.133 as shown in the table below.

[0183] [Table 2]

[0184] FIG. 8 illustrates generally some components of a network including a node according to some configurations; FIG. 9 illustrates generally some method steps performed according to some configurations.

[0185] 8 illustrates schematically some components of a network including nodes according to some configurations. The network 1000 includes a plurality of TRPSs 1200A, 1200B in communication with a user equipment 1200.

[0186] The user equipment 1100: means 1110 for indicating to another node 1200A that multiple timing advance loops are supported; means 1120 for receiving from another node 1200A a configuration for measuring a received reference signal from another node 1200A, 1200B; means 1130 for performing measurements on a received reference signal according to the configuration; and means 1140 for evaluating, based on the measurement and based on the conditional use of at least one timing advance loop, an indication of a predicted signal quality metric associated with at least one of: another node 1200A or a further node 1200B; means 1150 for transmitting information related to the evaluated indication of the predicted signal quality metric at at least one of the another node 1200 and the further node 1200B; The device takes the form of an apparatus comprising:

[0187] Network node 1200A: means 1210 for determining that multiple timing advance loops are supported by the node; means 1220 for transmitting to the node 1100 a configuration for measuring the received reference signal; means 1230 for receiving from the node 1100 information relating to an evaluated indication of a predicted signal quality metric at at least one of another node or a further network node 1200B; The device takes the form of an apparatus comprising:

[0188] FIG. 9 illustrates schematically method steps performed according to some configurations.

[0189] User equipment 1100 may be configured to perform a method including the following steps: 9110: indicating to another node that multiple timing advance loops are supported; 9120: receiving from another node a configuration for measuring a received reference signal from the other node; 9130: Performing measurements on the received reference signal according to the configuration; 9140: Based on the measurement, based on the use of a common timing advance loop: evaluating an indication of a predicted signal quality metric associated with at least one of another node or a further node; 9150: Transmitting information related to the evaluated indication of the predicted signal quality metric at at least one of the other node and the further node.

[0190] The network node 1200A may be configured to perform a method including the following steps: 9210: Determining that multiple timing advance loops are supported by the node; 9220: Transmitting a configuration to the node for measuring the received reference signal; 9230: Receiving information from the node relating to an evaluated indication of a predicted signal quality metric at at least one of another node or a further node.

[0191] Those skilled in the art will readily understand that the steps of the various above-described methods may be performed by a programmed computer. Some embodiments herein are also intended to cover program storage devices, e.g., digital data storage media, that are machine- or computer-readable and encode a machine-executable or computer-executable program of instructions, which perform some or all of the above-described method steps. The program storage device may be, for example, a digital memory, a magnetic storage medium such as a magnetic disk or magnetic tape, a hard drive, or an optically readable data storage medium. Embodiments are also intended to cover computers programmed to perform the above-described method steps. The term non-transitory, as used herein, is a limitation of the medium itself (i.e., tangible, not a signal), as opposed to a limitation on data storage permanence (e.g., RAM vs. ROM).

[0192] As used herein, the term "circuitry" may refer to one or more or all of the following: (a) hardware-only circuit implementations (e.g., implementations using only analog and / or digital circuitry); and (b) Combinations of hardware circuitry and software, such as (where applicable): (i) a combination of analog and / or digital hardware circuitry and software / firmware; and (ii) any portion of a hardware processor (including a digital signal processor) with software, software, and memory that cooperate to cause a device, such as a mobile phone or server, to perform various functions; and (c) A hardware circuit and / or processor, such as a microprocessor or portion of a microprocessor, that requires software (e.g., firmware) to operate, but that may not be present when software is not required for operation.

[0193] This definition of circuit applies to all uses of the term herein, including within any claims. As a further example, as used herein, the term circuit also encompasses simply a hardware circuit or processor (or processors), or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware implementation. The term circuit also encompasses, for example, and where applicable to particular claim elements, a baseband or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0194] Although exemplary embodiments of the present invention are described in the preceding paragraphs with reference to various examples, it should be understood that modifications to the examples given can be made without departing from the scope of the present invention as claimed.

[0195] Features set out in the preceding description may be used in combinations other than those expressly set out.

[0196] Although functions are described with reference to particular features, those functions may be implemented by other features, whether or not described.

[0197] Although features are described with reference to particular embodiments, those features may also be present in other embodiments, whether or not described.

[0198] While attempting to draw attention to those features of the invention that are considered to be of particular importance in the foregoing specification, it should be understood that applicant claims protection with respect to any previously patentable feature or combination of features referenced and / or shown in the drawings, whether or not specific emphasis is placed thereon.

Claims

1. at least one processor; at least one memory containing computer program code; an apparatus comprising at least one memory and computer program code that, using at least one processor, causes the apparatus to: Allowing another node to indicate that multiple timing advance loops are supported; receiving, from another node, a configuration for measuring a received reference signal from the other node; causing measurements to be made on a received reference signal according to the configuration; evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the another node or a further node based on the conditional use of the at least one timing advance loop; transmitting information relating to an evaluated indication of a predicted signal quality metric associated with at least one of another node and a further node; The apparatus is configured to:

2. The apparatus of claim 1 , wherein the configuration for measuring the received reference signal includes an indication of one or more signal quality metrics to be evaluated.

3. 3. The apparatus of claim 2, wherein the one or more signal quality metrics to be evaluated include an indication of interference or an indication of signal spreading at another or further node as a result of the conditional use of at least one timing advance loop.

4. 4. The apparatus of claim 2 or 3, wherein the one or more signal quality metrics to be evaluated include an indication of interference caused by timing deviations caused at another or further node based on conditional use of at least one timing advance loop.

5. 5. The apparatus of claim 1, wherein the arrangement for measuring the received reference signal comprises a threshold predictive quality metric.

6. At least one memory and computer program code are used to cause the apparatus, using at least one processor, to:

6. The apparatus of claim 5, configured to cause an evaluated indication of a predicted signal quality metric at another or further node to be compared with a threshold predicted quality metric.

7. 7. The apparatus of claim 6, wherein the transmitted information relating to the evaluated indication of a predicted signal quality metric associated with at least one of the another node or the further node includes an indication of whether the predicted signal quality metric is above or below a threshold.

8. 8. The apparatus of claim 1, wherein the apparatus comprises a user equipment and the further node comprises a network node.

9. The apparatus of claim 1 , wherein the further node comprises a network node.

10. The apparatus of claim 1 , wherein the another node and the further node comprise different physical nodes or the same physical node.

11. The apparatus of claim 1 , wherein the received reference signal comprises a downlink signal.

12. 12. Apparatus according to any preceding claim, wherein the received reference signal comprises a signal received from at least one of another node or a further node.

13. 13. The apparatus of claim 1, wherein the evaluated indication of a predicted signal quality metric comprises an evaluated indication of a predicted uplink signal quality metric.

14. At least one memory and computer program code are used to cause the apparatus, using at least one processor, to:

14. The apparatus of claim 1, configured to receive, in response to transmitting information regarding an evaluated indication of a predicted signal quality metric associated with the another node or at least one of the further node, enablement of an additional timing advance loop to be applied in connection with communication with the another node or at least one of the further node.

15. at least one processor; at least one memory containing computer program code; an apparatus comprising at least one memory and computer program code that, using at least one processor, causes the apparatus to: determining that multiple timing advance loops are supported by the node; causing the node to transmit a configuration for measuring the received reference signal; receiving information from the node relating to an evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node; The apparatus is configured to:

16. At least one memory and computer program code are used to cause the apparatus, using at least one processor, to:

16. The apparatus of claim 15, configured to compare information regarding an evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node to a threshold predicted quality metric to determine whether to enable an additional timing advance loop.

17. At least one memory and computer program code are used to cause the apparatus, using at least one processor, to:

16. The apparatus of claim 15, configured to cause evaluation of information relating to an evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node to assess whether a threshold predicted quality metric is met.

18. At least one memory and computer program code are used to implement the device using at least one processor.

18. The apparatus of claim 16 or 17, configured to cause transmission of at least one additional timing advance loop enablement in response to a determination based on the received evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node.

19. 19. The apparatus of any one of claims 15 to 18, wherein the apparatus comprises a network node, and the node comprises user equipment.

20. 20. The apparatus of any one of claims 15 to 19, wherein the further node comprises a network node.

21. 21. The apparatus of claim 15, wherein the received reference signal comprises a downlink signal.

22. 22. Apparatus according to any one of claims 15 to 21, wherein the received reference signal comprises a signal received at the user equipment from at least one of another node or a further node.

23. 23. The apparatus of any one of claims 15 to 22, wherein the evaluated indication of a predicted signal quality metric comprises an evaluated indication of a predicted uplink signal quality metric.

24. 24. Apparatus according to any one of claims 15 to 23, wherein the configuration for measuring the received signal includes an indication of one or more signal quality metrics to be evaluated.

25. 25. The apparatus of claim 24, wherein the one or more signal quality metrics to be evaluated include an indication of interference or an indication of signal spreading at at least one of another node or a further node as a result of the conditional use of at least one timing advance loop.

26. 26. Apparatus according to any one of claims 15 to 25, wherein the arrangement for measuring the received reference signal comprises a threshold predictive quality metric.

27. indicating to another node that multiple timing advance loops are supported; and receiving, from another node, a configuration for measuring a received reference signal from the other node; performing measurements on a received reference signal according to the configuration; evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the another node or a further node based on the conditional use of the at least one timing advance loop; transmitting information related to the evaluated indication of the predicted signal quality metric associated with at least one of the other node or the further node; A method comprising:

28. 28. The method of claim 27, wherein the other node comprises a network node.

29. 29. The method of claim 27 or 28, wherein the further node comprises a network node.

30. 30. The method of any one of claims 27 to 29, wherein the received reference signal comprises a downlink signal.

31. 31. A method according to any one of claims 27 to 30, wherein the received reference signal comprises a signal received from at least one of another node or a further node.

32. 32. A method according to any one of claims 27 to 31, wherein the evaluated indication of a predicted signal quality metric comprises an evaluated indication of a predicted uplink signal quality metric.

33. 33. A method according to any one of claims 27 to 32, wherein the configuration for measuring the received reference signal includes an indication of one or more signal quality metrics to be evaluated.

34. 34. The method of claim 33, wherein the one or more signal quality metrics to be evaluated include an indication of interference or an indication of signal spreading at another or further node as a result of the conditional use of at least one timing advance loop.

35. 34. The method of claim 33, wherein the one or more signal quality metrics to be evaluated include an indication of interference caused by timing deviations caused at another or further node based on conditional use of at least one timing advance loop.

36. 36. A method according to any one of claims 27 to 35, wherein the arrangement for measuring the received reference signal comprises a threshold predictive quality metric.

37. 37. A method according to any one of claims 27 to 36, further comprising comparing the evaluated indication of a predicted signal quality metric at another or further node to a threshold predicted quality metric.

38. 38. A method according to any one of claims 27 to 37, wherein the transmitted information relating to an evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node includes an indication of whether the predicted signal quality metric is above or below a threshold.

39. 39. The method of any one of claims 27 to 38, further comprising receiving, in response to transmitting information regarding the evaluated indication of a predicted signal quality metric associated with the another node or at least one of the further node, enablement of an additional timing advance loop to be applied in connection with communications with the another node or at least one of the further node.

40. determining that multiple timing advance loops are supported by the node; transmitting a configuration to the node for measuring the received reference signal; receiving information from the node relating to an evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node; A method comprising:

41. 41. A computer program product operable to perform the method of any one of claims 27 to 40 when executed on a computer.

42. 41. A non-transitory computer readable medium storing computer program code comprising instructions that, when executed by a processor, cause an apparatus to perform the method of any one of claims 27 to 40.

43. a means for indicating to another node that multiple timing advance loops are supported; means for receiving from another node a configuration for measuring a received reference signal from the other node; means for performing measurements on a received reference signal in accordance with the configuration; means for evaluating, based on the measurements, an indication of a predicted signal quality metric associated with at least one of the other node or the further node based on the conditional use of the at least one timing advance loop; means for transmitting information related to the evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node; An apparatus comprising:

44. means for determining that multiple timing advance loops are supported by the node; means for transmitting to the node a configuration for measuring the received reference signal; means for receiving from the node information relating to an evaluated indication of a predicted signal quality metric associated with at least one of another node or a further node; An apparatus comprising:

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