Reference signal selection for determining beam failure detection and radio link monitoring

Abstract

Embodiments include computer-readable storage media, user equipment, methods, and integrated circuits that perform operations including receiving a plurality of control resource sets (CORESETs), selecting at least one reference signal (RS) corresponding to at least one activated transmission configuration indicator (TCI) state in the CORESETs, analyzing the at least one RS, and determining beam failure detection (BFD) or radio link monitoring (RLM) based on the selected at least one reference signal.

Description

[Background technology]

[0001] A User Equipment (UE) can establish a connection to at least one of a plurality of different networks or types of networks. When establishing a network connection, such as a connection to a 5G New Radio (NR) network, a g-NodeB (gNB) transmits Downlink Control Information (DCI) to the UE over a Physical Downlink Control Channel (PDCCH) in a Search Space (SS).

[0002] The PDCCH and DCI are transmitted to the UE via one or more control resource sets (CORESETs), each of which includes a transmission configuration indicator (TCI) state configured by the gNB. The PDCCH may include synchronization signal blocks (SSBs) and channel state information (CSI) reference signals (RSs) that the UE can use to determine an expected block error rate (BLER). The UE uses the BLER to determine beam failure detection (BFD) and / or radio link monitoring (RLM). When the expected BLER for all RSs exceeds a predetermined threshold, the UE can count a beam failure case (for BFD) or determine that the RS is out of synchronization (for RLM). Summary of the Invention

[0003] Some example embodiments include a computer-readable storage medium including a set of instructions that, when executed by a processor, cause the processor to perform operations including receiving a plurality of control resource sets (CORESETs), selecting at least one reference signal (RS) corresponding to at least one activated transmission configuration indicator (TCI) state in the CORESETs, analyzing the at least one RS, and determining beam failure detection (BFD) or radio link monitoring (RLM) based on the selected at least one reference signal.

[0004] Another example embodiment relates to a user equipment (UE) including a transceiver and a processor configured to connect to one or more gNodeBs (gNBs). The processor is configured to receive a plurality of control resource sets (CORESETs) from the gNBs, select at least one reference signal (RS) corresponding to at least one activated transmission configuration indicator (TCI) state in the CORESET, analyze the at least one RS, and determine beam failure detection (BFD) and radio link monitoring (RLM) based on the selected at least one reference signal. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 illustrates an exemplary network arrangement in accordance with various exemplary embodiments. [Figure 2] FIG. 1 illustrates an exemplary UE in accordance with various exemplary embodiments. [Figure 3A] FIG. 1 illustrates a method for determining reference signal(s) (RS) for beam failure detection and radio link monitoring, according to various exemplary embodiments. [Figure 3B] FIG. 1 illustrates a method for determining an RS for beam failure detection and radio link monitoring, according to various exemplary embodiments. [Figure 3C]FIG. 1 illustrates a method for determining an RS for beam failure detection and radio link monitoring, according to various exemplary embodiments. [Figure 4A] 1 is a block diagram illustrating an example of RS selection, in accordance with various exemplary embodiments. [Figure 4B] 1 is a block diagram illustrating an example of RS selection, in accordance with various exemplary embodiments. [Figure 4C] 1 is a block diagram illustrating an example of RS selection, in accordance with various exemplary embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0006] Exemplary embodiments may be further understood with reference to the following description and associated accompanying drawings, in which like elements are designated with the same reference numerals. Exemplary embodiments relate to a user equipment (UE) transmitting UCI information to a gNodeB (gNB) of a 5G New Radio (NR) network. Exemplary embodiments relate to reception of a PDCCH by the UE and robustness of reception.

[0007] The exemplary embodiments are described with reference to a UE. However, the use of a UE is merely for illustrative purposes. The exemplary embodiments may be used with any electronic component, which is capable of establishing a connection with a network and is configured with hardware, software, and / or firmware for exchanging information and data with the network. Accordingly, the UE described herein is used to represent any electronic component.

[0008] The exemplary embodiments are also described with respect to networks including 5G New Radio (NR) Radio Access Technology (RAT). However, the exemplary embodiments are not limited to the 5G RAT, as they may be applied to any network that includes functionality described herein for the 5G RAT (whether described using the same or different terminology), e.g., beamforming, reference signals, TCI state, etc.

[0009] Currently, the PDCCH includes one TCI state configured for each CORESET. According to an example embodiment, each CORESET may be configured with multiple TCI states by the gNB so that one PDCCH can be transmitted via multiple beams. In such a scenario, the UE is configured to select one or more reference signals (RSs) from the TCI states of the CORESET and / or calculate an expected block error rate (BLER) to select an RS to be used in beam failure detection (BFD) and radio link monitoring (RLM). However, in such a deployment, the UE may need to determine how to select RS(s) to perform RLM / BFD and how to detect the expected BLER based on these RSs. Example embodiments also address these issues.

[0010] 1 illustrates an exemplary network deployment 100 in accordance with various exemplary embodiments. The exemplary network deployment 100 includes a UE 110. Those skilled in the art will appreciate that the UE 110 may be any type of electronic component configured to communicate over a network, such as a mobile phone, a tablet computer, a desktop computer, a smartphone, a phablet, an embedded device, an Internet of Things (IoT) wearable device, or the like. It should also be understood that an actual network deployment may include any number of UEs used by any number of users. Thus, the example of a single UE 110 is provided for illustrative purposes only.

[0011] The UE 110 may be configured to communicate with one or more networks. In the example network configuration 100, the networks with which the UE 110 may wirelessly communicate are a 5G New Radio (NR) Radio Access Network (5G NR-RAN) 120, an LTE Radio Access Network (LTE-RAN) 122, and a Wireless Local Access Network (WLAN) 124. However, it should be understood that the UE 110 may also communicate with other types of networks, and that the UE 110 may also communicate with a network via a wired connection. Thus, the UE 110 may include a 5G NR chipset for communicating with the 5G NR-RAN 120, an LTE chipset for communicating with the LTE-RAN 122, and an ISM chipset for communicating with the WLAN 124.

[0012] The 5G NR-RAN 120 and the LTE-RAN 122 may be parts of a cellular network that may be deployed by a cellular provider (e.g., Verizon, AT&T, Sprint, T-Mobile, etc.). These networks 120, 122 may include, for example, cells or base stations (Node Bs, eNodeBs, HeNBs, eNBSs, gNBs, gNodeBs, macro cells, micro cells, small cells, femto cells, etc.) configured to transmit and receive traffic from UEs equipped with appropriate cellular chipsets. The WLAN 124 may include any type of wireless local area network (e.g., WiFi, Hot Spot, IEEE 802.11x network, etc.).

[0013] The UE 110 can connect to the 5G NR-RAN 120 via a gNB 120A. The gNB 120A may be configured with the necessary hardware (e.g., antenna array), software, and / or firmware to perform massive multiple-input multiple-output (MIMO) functionality. Massive MIMO may refer to a base station configured to generate multiple beams for multiple UEs. In operation, the UE 110 may be within range of multiple gNBs. Thus, either simultaneously or alternatively, the UE 110 may also connect to the 5G NR-RAN 120 via a gNB 120B. The reference to two gNBs 120A, 120B is for illustrative purposes only. The illustrative embodiments may apply to any appropriate number of gNBs. Additionally, the UE 110 may communicate with an eNB 122A of the LTE-RAN 122 to send and receive control information used for downlink and / or uplink synchronization for the 5G NR-RAN 120 connection.

[0014] Those skilled in the art will appreciate that any association procedure may be performed by the UE 110 to connect to the 5G NR-RAN 120. For example, as discussed above, the 5G NR-RAN 120 may be associated with a particular cellular provider for which the UE 110 and / or the user of the UE 110 has contract and credential information (e.g., stored on a SIM card). Upon detecting the presence of the 5G NR-RAN 120, the UE 110 may transmit the corresponding credential information to associate with the 5G NR-RAN 120. More specifically, the UE 110 may associate with a particular base station (e.g., a gNB 120A of the 5G NR-RAN 120).

[0015] In addition to networks 120, 122, and 124, network deployment 100 also includes a cellular core network 130, the Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network services backbone 160. Cellular core network 130 may be considered an interconnected set of components that manage the operation and traffic of a cellular network. Cellular core network 130 also manages traffic flowing between the cellular network and the Internet 140. IMS 150 may generally be described as an architecture for delivering multimedia services to UE 110 using IP protocols. IMS 150 can communicate with cellular core network 130 and Internet 140 to provide multimedia services to UE 110. Network services backbone 160 communicates either directly or indirectly with Internet 140 and cellular core network 130. The network services backbone 160 may generally be described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that may be used to extend the functionality of the UE 110 in communicating with various networks.

[0016] 2 illustrates an exemplary UE 110 in accordance with various exemplary embodiments. The UE 110 will be described with respect to the network arrangement 100 of FIG. 1. The UE 110 may represent any electronic device and may include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. The other components 230 may include, for example, an audio input device, an audio output device, a battery for providing a limited power source, a data acquisition device, a port for electrically connecting the UE 110 to other electronic devices, one or more antenna panels, etc.

[0017] The processor 205 may be configured to execute multiple engines of the UE 110. For example, the engines may include a BFD / RLM management engine 235. The BFD / RLM management engine 235 may perform various operations related to selecting one or more RSs configured in the TCI state of the CORESET, determining the BLER of the selected RS(s), and / or determining BFD and RLM based on the RS(s).

[0018] The above-described engines, which are applications (e.g., programs) executed by the processor 205, are exemplary only. The functionality associated with the engines may also be represented as separate, integrated components of the UE 110, or may be modular components coupled to the UE 110, such as integrated circuits with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engines may also be embodied as one application or separate applications. Additionally, in some UEs, the functionality described for the processor 205 is divided between two or more processors, such as a baseband processor and an application processor. Example embodiments may be implemented in any of these or other configurations of a UE.

[0019] The memory device 210 may be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 may be a hardware component configured to present data to a user, and the I / O device 220 may be a hardware component that allows a user to provide input. The display device 215 and the I / O device 220 may be separate components or may be integrated together, such as a touchscreen. The transceiver 225 may be a hardware component configured to establish a connection with the 5G NR-RAN 120, the LTE-RAN 122, the WLAN 124, etc. Thus, the transceiver 225 may operate at a variety of different frequencies or channels (e.g., a set of contiguous frequencies).

[0020] 3A illustrates a method 300 for determining RSs for beam failure detection and radio link monitoring according to various exemplary embodiments. Method 300 is performed by UE 110 to enable selection of RS(s) for determining BFD and RLM. At 305, the UE receives a CORESET configured by gNB 120A or 120b. In some embodiments, the gNB may explicitly configure the RSs that UE 110 will use for BFD and RLM. In such a scenario, method 300 skips to 320 and determines BFD and RLM using the explicitly configured RSs. However, if the gNB does not explicitly configure BFD / RLM RSs, the method proceeds to 310.

[0021] At 310, the UE selects all of the RSs in all TCI states of the CORESET. Then, at 315, the UE 110 calculates the expected BLER for these RSs. In some embodiments, the UE 110 calculates the expected BLER for each of the selected RSs. In some embodiments, the UE 110 calculates a combined expected BLER for all of the selected RSs.

[0022] In some embodiments, the combined expected BLER is determined using the Signal to Interference and Noise Ratio (SINR) from all of the RSs. In some embodiments, the minimum SINR may be used to determine the combined expected BLER. In some embodiments, the maximum SINR may alternatively be used to determine the combined expected BLER. In some embodiments, the average SINR may alternatively be used to determine the combined expected BLER.

[0023] In some embodiments, the combined expected BLER is determined using the measured BLERs from all of the RSs. In some embodiments, the minimum measured BLER may be used to determine the combined expected BLER. In some embodiments, alternatively, the maximum measured BLER may be used to determine the combined expected BLER. In some embodiments, alternatively, the average measured BLER may be used to determine the combined expected BLER.

[0024] It can be seen from the above examples that there are multiple mathematical and / or statistical methods for combining measurements for RS to calculate an expected BLER, and therefore it should be understood that example embodiments may include any method for combining RS measurements.

[0025] Typically, a gNB uses the same transmit power to transmit different RSs. However, in some cases, there may be a difference in transmit power (power offset) between the selected RSs. In such cases, the UE 110 may take the power offset into account when determining the combined expected BLER. In some embodiments, a minimum power offset may be used to determine the combined expected BLER. In some embodiments, a maximum power offset may be used to determine the combined expected BLER. In some embodiments, an average power offset may be used to determine the combined expected BLER. It should be noted that in such a scenario, the gNB 120A or 120B may communicate the power offsets of the respective RSs to the UE 110 via Radio Resource Control (RRC) signaling.

[0026] At 320, UE 110 compares either the calculated expected BLER for each of the RSs or the combined expected BLER with a predetermined threshold. If the expected BLER for all of the selected RSs exceeds the predetermined threshold, at 325, UE 110 determines that a beam failure case exists (for BFD) and / or that an out-of-sync beam exists (for RLM).

[0027] 3B illustrates a method 340 for determining RSs for beam failure detection and radio link monitoring according to various exemplary embodiments. Method 350 is also performed by UE 110 to enable selection of RSs for determining BFD and RLM. In some cases, gNB 120a or 120b may transmit several CORESETs. Sometimes, the number of CORESETs (active TCI states) may exceed the number of RSs that UE 110 can use to determine BFD / RLM. In such cases, UE 110 may prioritize and select a subset of CORESETs.

[0028] At 345, UE 110 receives a CORESET configured by gNB 120A or 120B. At 350, UE 110 determines whether the number of RSs that can be used for BFD / RLM is less than the number of active TCI states in the active bandwidth portion that includes the CORESET. If the number of RSs is less than the number of active TCI states, the UE proceeds to 355, discussed below. If the number of RSs is not less than the number of active TCI states, UE 110 proceeds to 360, where UE 110 selects all of the RSs in all of the TCI states. If all RSs have been selected, the method may proceed as described above with reference to 315-320 of FIG. 3A.

[0029] At 355, because the number of RSs used for BFD / RLM is less than the number of active TCI states, UE 110 selects an RS for BFD / RLM based on, for example, the number of TCI states in a given CORESET, the periodicity of the associated search space (SS), or the CORESET ID. In some exemplary embodiments, UE 110 initially gives higher priority to CORESET(s) with a higher number of active TCI states. If two or more CORESETs have the same number of active TCI states, the CORESET with the smaller minimum periodicity between associated SSs may be selected. However, if the minimum periodicity is the same for the CORESETs, the CORESET with the smaller CORESET ID may be selected.

[0030] 4A-4C are block diagrams illustrating examples of RS selection processes, according to various exemplary embodiments. These figures provide visual examples of the selection process discussed above in FIGS. 3A and 3B. However, it should be noted that these visualizations are provided as examples and do not limit the number of different scenarios and criteria for RS selection by a UE.

[0031] 4A-4C, it is assumed that UE 110 can use only up to four RSs for BFD / RLM. As shown in FIGS. 4A-4C, five TCI states may be configured for the three CORESETs configured by gNB 120a or 120b. CORESET 1, corresponding to SS 1, may include TCI 1 and TC2. CORESET 2, corresponding to SS 2, may include TCI 3. CORESET 3, corresponding to SS 3, may include TCI 4 and TCI 5. Each TCI state has a corresponding CSI-RS, which has a number corresponding to the individual TCI state of the CSI-RS.

[0032] In the example shown in FIG. 4A , UE 110 selects a CORESET based on the above selection criteria, e.g., first priority is given to the CORESET with the most TCI states. In this case, CORESET 1 and CORESET 3 have two TCIs, compared to CORESET 2, which has one TCI, so these CORESETs are prioritized and selected. This results in the selection of CSI-RS 1, CSI-RS 2, CSI-RS 4, and CSI-RS 5 for BFD / RLM, as shown in FIG. 4A . Because the maximum number of RSs was determined based on the first priority criterion, e.g., the number of TCI states per CORESET, further priority criteria, e.g., periodicity and CORESET ID, were not used in this example. However, if fewer than the maximum number of RSs were selected based on the first priority criterion, additional criteria may be applied to determine the maximum number of RSs.

[0033] In some embodiments, the UE 110 may alternatively first select a CORESET with a smaller minimum periodicity between associated SSs. However, if the minimum periodicity is the same for the CORESETs, the CORESET with the smaller CORESET ID is selected. In some embodiments, the number of remaining RSs that can be used by the UE 110 for BFD / RLM may still be less than the number of active TCI states for a given CORESET. In some embodiments, the UE 110 may ignore (not select) such a CORESET.

[0034] The example shown in FIG. 4B illustrates an exemplary selection process in which UE 110 prioritizes periodicity and ignores the remaining CORESETs, as described above. Thus, in this example, UE 110 selects CORESET 1, which has a periodicity of 5 ms, and CORESET 2, which has a periodicity of 10 ms. This selection results in three RSs: CSI-RS 3, CSI-RS 1, and CSI-RS 2. Although three RSs are less than the four RSs UE 110 can use, CORESET 3 has two configured TCI states. Selecting CORESET 3 results in five RSs, which is more than the exemplary maximum of four RSs, and therefore UE 110 cannot perform BFD / RLM for this CORESET. Therefore, CORESET 3 is ignored, and the originally selected three RSs are used.

[0035] In some embodiments, UE 110 may fill in the maximum number of RSs by selecting a subset of TCI states for a particular CORESET. This selection of the subset of TCI states may be based on the RS periodicity of the TCI states (e.g., the smallest periodicity), or, if the periodicity is the same, based on the TCI state ID (e.g., the lowest TCI state ID).

[0036] The example shown in Figure 4C is substantially similar to the example of Figure 4B. However, in Figure 4C, UE 110 uses the above selection criteria to select one RS from CORESET 3 (the RS with the lesser periodicity) instead of ignoring CORESET 3. Thus, in this example, the resulting RSs are CSI-RS 3, CSI-RS 1, CSI-RS 2, and CSI-RS 5, with CSI-RS 5 filling out the RSs to a maximum of four.

[0037] In some embodiments, UE 110 may count RSs corresponding to different activated TCI states for a CORESET as one RS for BFD / RLM purposes, and the number of CORESETs may still be determined using the periodicity of the associated SS and the CORESET-ID, as described above.

[0038] Returning to FIG. 3B, after selecting the RS, at 365, UE 110 may use the measured RS to determine BFD and / or RLM.

[0039] 3C illustrates a method 370 for determining an RS for beam failure detection and radio link monitoring according to various exemplary embodiments. Method 370 is also performed by UE 110 to enable RS selection for determining BFD and RLM. At 375, UE 110 receives a CORESET configured by gNB 120A or 120B. At 380, UE 110 selects one RS from all of the TCI states. In some embodiments, the selection of a single RS may be configured by the gNB via higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) Control Element (CE), etc.).

[0040] In some embodiments, the UE 110 may select an RS based on one or more predetermined criteria. In some embodiments, the predetermined criteria may include, for example, a TCI state ID, a periodicity of the RS associated with the TCI, a resource type (e.g., periodic, aperiodic, semi-persistent), an RS resource ID, a measured or most recently reported Reported Reference Signal Received Power (RSRP) or SINR, and / or a transmit power. For example, the UE 110 may select an RS with the smallest periodicity. If two or more RSs have the same periodicity, the UE 110 may select an RS associated with a TCI with the lowest TCI state ID. Alternatively, the UE 110 may select an RS with, for example, the highest measured / reported RSRP or SINR. Alternatively, the UE 110 may select an RS with, for example, the highest transmit power.

[0041] At 385, the UE 110 calculates the expected BLER based on the selected RS. At 390, the UE 110 determines the BFD and RLM.

[0042] Although the present application describes various embodiments, each having different features in various combinations, it will be understood by those skilled in the art that any of the features of one embodiment may be combined with the features of other embodiments in a manner that is not specifically disallowed or is not functionally or logically inconsistent with the operation or described functionality of the device of the disclosed embodiment.

[0043] It is well understood that use of personal information should comply with generally recognized privacy policies and practices that meet or exceed industry or government requirements for maintaining user privacy. In particular, personal information data should be managed and handled in a manner that minimizes the risk of unintended or unauthorized access or use, and the nature of permitted uses should be clearly indicated to users.

[0044] Those skilled in the art will appreciate that the above exemplary embodiments may be implemented in any suitable software or hardware configuration, or combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel® x86-based platforms with compatible operating systems, Windows OS, Mac platforms and mobile devices with operating systems such as MAC OS, iOS, Android®, etc. In a further example, the exemplary embodiments of the above methods may be embodied as a program including lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, may be executed on a processor or microprocessor.

[0045] It will be apparent to those skilled in the art that various modifications may be made in the present disclosure without departing from the spirit or scope of the disclosure. Thus, the present disclosure is intended to cover the modifications and variations of the present disclosure provided they come within the scope of the appended claims and their equivalents.

Claims

1. 1. A computer-readable storage medium comprising a set of instructions, the set of instructions, when executed by a processor, causing the processor of a user equipment (UE) to: receiving a plurality of control resource sets (CORESETs); selecting a plurality of Reference Signals (RSs) corresponding to a plurality of activated Transmission Configuration Indicator (TCI) states in the CORESET; analyzing the plurality of RSs for beam failure detection (BFD); Execute an operation including and if the UE is configured to use a maximum number of RSs for BFD, and the maximum number of RSs is less than the plurality of activated TCI states, selecting the plurality of RSs based on a periodicity of a search space, wherein selecting the plurality of RSs includes determining whether a first search space associated with a first CORESET ID among a plurality of CORESETs and a second search space associated with a second CORESET ID among the plurality of CORESETs have the same periodicity, and if the first search space and the second search space have the same periodicity, selecting the plurality of RSs based on a maximum signal-to-interference-and-noise ratio (SINR). A computer-readable storage medium.

2. analyzing the plurality of RSs Calculating an expected block error rate (BLER) for the plurality of RSs; comparing the expected BLER to a predetermined threshold; and counting a beam failure case or an out-of-sync case if the expected BLER is more than the predetermined threshold.

3. The computer-readable storage medium of claim 2 , wherein the expected BLER is determined for each of the plurality of RSs.

4. The computer-readable storage medium of claim 3 , wherein the expected BLER is determined using signal-to-interference-and-noise ratios (SINRs) from all of the RSs.

5. The computer-readable storage medium of claim 3 , wherein the expected BLER is determined using a power offset of a transmit power for each of the plurality of RSs.

6. The computer-readable storage medium of claim 1 , wherein the operation is performed when a network does not explicitly configure a BFD reference signal.

7. a transceiver configured to connect to one or more gNodeBs (gNBs); 1. A user equipment (UE) including a processor, the processor: Receive a plurality of control resource sets (CORESETs) from the gNB; Selecting a plurality of Reference Signals (RSs) corresponding to a plurality of activated Transmission Configuration Indicator (TCI) states in the CORESET; analyzing the plurality of RSs; It is configured as follows: the UE is configured to use a maximum number of RSs for BFD, and when the maximum number of RSs is less than the plurality of activated TCI states, select the plurality of RSs based on periodicity of associated search spaces, wherein selecting the plurality of RSs includes determining whether a first search space associated with a first CORESET ID among a plurality of CORESETs and a second search space associated with a second CORESET ID among the plurality of CORESETs have the same periodicity, and when the first search space and the second search space have the same periodicity, selecting the plurality of RSs based on a maximum signal-to-interference-and-noise ratio (SINR). UE.

8. the processor: Calculating an expected block error rate (BLER) for the plurality of RSs; and comparing the expected BLER to a predetermined threshold, thereby Analyzing the plurality of RSs; The UE of claim 7 , wherein a beam failure case or an out-of-sync case is counted if the expected BLER is greater than the predetermined threshold.

9. The UE of claim 8 , wherein the expected BLER is determined for each of the plurality of RSs.

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