Method for monitoring downlink control information CORESET of source and target cells during handover

Abstract

Certain aspects of the present disclosure provide techniques for configuring downlink control information (DCI) monitoring of a source cell and a target cell during a make-before-break (MBB) handover.

Description

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62 / 892,981, filed on August 28, 2019, which is incorporated herein by reference in its entirety.

[0002] background

[0003] Public domain

[0004] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for monitoring downlink control information (DCI) in a multi-cell scenario.

[0005] Related technical description

[0006] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name just a few.

[0007] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhancement set of the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0008] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunication standards that employ these technologies.

[0009] Overview

[0010] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed in the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," it will be understood how the features of the present disclosure provide advantages including improved techniques for monitoring DCI in a build-before-break (MBB) handover scenario.

[0011] Certain aspects provide a method for wireless communication by a user equipment (UE). The method generally includes: determining a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; determining a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; and monitoring physical downlink control channel (PDCCH) transmissions in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the handover procedure.

[0012] Certain aspects provide a method for wireless communications by a network entity. The method generally includes: configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; and configuring the UE with a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure.

[0013] Certain aspects provide a method for wireless communication by a user equipment (UE). The method generally includes: determining a number of control resource sets (CORESETs) to be monitored by the UE when the UE is maintaining connectivity with both a source cell and a target cell during a handover procedure; deciding which of the overlapping monitoring opportunities to monitor in a situation where monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously based on a drop rule; and monitoring a physical downlink control channel (PDCCH) transmission according to the decision during the handover procedure.

[0014] Certain aspects provide a method for wireless communication by a network entity. The method generally includes: configuring a user equipment (UE) with a number of control resource sets (CORESETs) to monitor when the UE is maintaining connectivity with both a source cell and a target cell during a handover procedure; and configuring a drop rule for the UE to decide which of the overlapping monitoring opportunities to monitor in a situation where monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0015] Aspects of the present disclosure provide various apparatuses, devices, and computer-readable media for (or capable of) performing the operations described above.

[0016] To achieve the foregoing and related ends, the one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are only indicative of several of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to understand in detail the manner in which the above-stated features of the present disclosure are used, a more particular description of the content briefly summarized above may be made with reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain typical aspects of the present disclosure and are not to be considered limiting of its scope, as the description may admit to other equally effective aspects.

[0019] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0020] Figure 2 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0021] Figure 3 An example MBB handover procedure is illustrated.

[0022] Figure 4

[0013] Example operations for wireless communications by user equipment are illustrated, in accordance with certain aspects of the present disclosure.

[0023] Figure 5

[0013] Example operations for wireless communications by a network entity are illustrated in accordance with certain aspects of the present disclosure.

[0024] Figure 6 Illustrated are example PDCCH opportunities for source and target cells during MBB handover, in accordance with certain aspects of the present disclosure.

[0025] Figure 7

[0013] Example operations for wireless communications by user equipment are illustrated, in accordance with certain aspects of the present disclosure.

[0026] Figure 8

[0013] Example operations for wireless communications by a network entity are illustrated in accordance with certain aspects of the present disclosure.

[0027] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation.

[0028] Detailed Description

[0029] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for monitoring DCI of source and target cells during MBB handover.

[0030] The following description provides an example of monitoring DCI of source and target cells during MBB handover in a communication system, without limiting the scope, applicability, or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements discussed without departing from the scope of the present disclosure. Various examples may appropriately omit, replace, or add various procedures or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. Moreover, the features described with reference to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice a method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionalities, or structures and functionalities that are supplementary to or in addition to the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein may be implemented by one or more elements of the claims. The word "exemplary" is used herein to mean "used as an example, instance, or illustration". Any aspect described as "exemplary" herein is not necessarily to be interpreted as superior to or superior to other aspects.

[0031] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RAT may also be referred to as radio technology, air interface, etc. Frequency may also be referred to as carrier, subcarrier, frequency channel, frequency modulation, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, a 5G NR RAT network may be deployed.

[0032] Figure 1An example wireless communication network 100 is illustrated in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a NR system (e.g., a 5G NR network).

[0033] like Figure 1 As illustrated in , the wireless communication network 100 may include several base stations (BSs) 110a-z (each also individually referred to herein as BS 110 or collectively referred to as BS 110) and other network entities. BS 110 may provide communication coverage for a particular geographic area (sometimes referred to as a "cell"), which may be stationary or mobile depending on the location of mobile BS 110. In some examples, BS 110 may be interconnected to each other and / or to one or more other BSs or network nodes (not shown) in the wireless communication network 100 via various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network. Figure 1 In the example shown in , BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. The BS may support one or more cells. BS 110 communicates with user equipment (UE) 120a-y (each also individually referred to herein as UE 120 or collectively referred to as UE 120) in the wireless communication network 100. UE 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile.

[0034] According to certain aspects, BS 110 and UE 120 may be configured for the UE to configure and monitor DCI of the source cell and the target cell for MBB handover. Figure 1 As shown in , BS 110a includes an MBB manager 112. According to various aspects of the present disclosure, the MBB manager 112 may be configured to: detect that a user equipment (UE) is simultaneously connected to a first base station (BS) of a first cell and a second BS of a second cell during a handover of the UE from a first cell to a second cell; determine a configuration for the UE to monitor downlink control information (DCI) for the first and second cells, wherein the configuration is based on a priority associated with at least one of the first cell or the second cell; transmit the determined configuration to the UE; and transmit downlink control information (DCI) for the first and second cells according to the determined configuration. As shown in FIG. Figure 1As shown in , UE 120a includes an MBB manager 122. According to aspects of the present disclosure, the MBB manager 122 may be configured to: detect that the UE is simultaneously connected to a first base station (BS) of the first cell and a second BS of the second cell during a handover of the UE from the first cell to the second cell; receive a configuration for monitoring downlink control information (DCI) for the first and second cells, wherein the configuration is based on a priority associated with at least one of the first cell or the second cell; and monitor the DCI for the first and second cells based on the received configuration.

[0035] The wireless communication network 100 may also include a relay station (e.g., relay station 110r) (also referred to as a relay, etc.), which receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of data and / or other information to a downstream station (e.g., UE 120 or BS 110), or which relays transmissions between UEs 120 to facilitate communication between the devices.

[0036] A network controller 130 may couple to a set of BSs 110 and provide coordination and control for the BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other (eg, directly or indirectly) via a wireless or wired backhaul.

[0037] Figure 2 1 and 120a (eg, in the example embodiment of the present invention) that can be used to implement various aspects of the present disclosure. Figure 1 Example components of the wireless communication network 100).

[0038] At BS 110a, a transmit processor 220 may receive data from a data source 212 and control information from a controller / processor 240. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. The processor 220 may process (e.g., encode and symbol map) the data and the control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols (such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols, where applicable, and may provide an output symbol stream to modulators (MODs) 232a-232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a-232t may be transmitted via antennas 234a-234t, respectively.

[0039] At UE 120a, antennas 252a-252r may receive downlink signals from BS 110a and may provide received signals to demodulators (DEMODs) in transceivers 254a-254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all demodulators 254a-254r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120a to a data sink 260, and provide decoded control information to a controller / processor 280.

[0040] On the uplink, at the UE 120a, the transmit processor 264 may receive and process data from a data source 262 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 280 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 264 may also generate reference symbols for a reference signal (e.g., a sounding reference signal (SRS)). The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266, if applicable, further processed by a demodulator in a transceiver 254a-254r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At the BS 110a, the uplink signal from the UE 120a may be received by the antenna 234, processed by the modulator 232, detected by the MIMO detector 236, if applicable, and further processed by the receive processor 238 to obtain decoded data and control information sent by the UE 120a. Receive processor 238 may provide decoded data to data sink 239 and decoded control information to controller / processor 240 .

[0041] Memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively.A scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0042] The controller / processor 280 and / or other processors and modules at the UE 120a may perform or direct the execution of processes for the techniques described herein. For example, according to various aspects described herein, such as Figure 2 As shown in , the controller / processor 240 of BS110a has an MBB manager 241, which can be configured to: detect that during a user equipment (UE) switching from a first cell to a second cell, the UE is simultaneously connected to a first base station (BS) of the first cell and a second BS of the second cell; determine a configuration for the UE to monitor downlink control information (DCI) for the first and second cells, wherein the configuration is based on a priority associated with at least one of the first cell or the second cell; transmit the determined configuration to the UE; and transmit downlink control information (DCI) for the first and second cells according to the determined configuration. Figure 2As shown in , according to various aspects described herein, the controller / processor 280 of UE 120a has an MBB manager 241, which can be configured to: detect that the UE is simultaneously connected to a first base station (BS) of the first cell and a second BS of the second cell during a handover of the UE from the first cell to the second cell; receive a configuration for monitoring downlink control information (DCI) for the first and second cells, wherein the configuration is based on a priority associated with at least one of the first cell or the second cell; and monitor the DCI for the first and second cells based on the received configuration. Although shown at the controller / processor, other components of UE 120a and BS 110a can also be used to perform the operations described herein.

[0043] Example MBB handover procedure and CORESET configuration

[0044] One of the main goals of mobility enhancement is to achieve 0ms of service interruption during a UE handover from a source base station (BS) to a target BS. Some of the proposals being considered by 3GPP for NR include a build-before-break (MBB) type of handover, which is a Release 14 LTE feature and includes the UE maintaining a source link to the source BS while establishing a target link to the target BS in order to shorten or completely eliminate service interruption to the UE. During an MBB handover from a source BS (e.g., a source BS serving a source cell) to a target BS (e.g., a target BS serving a target cell), the UE is expected to maintain connectivity with both the source BS and the target BS until the UE has successfully camped on the target BS and can start receiving data from the target BS. In one aspect, the source and target BSs may be distributed units (DUs) / transmission reception points (TRPs) associated with different gNBs or the same gNB.

[0045] Figure 3 An example MBB handover procedure is illustrated. Figure 3 As shown in , the UE maintains the source connection and the target connection from steps 4 to 7 of the handover procedure.

[0046] In MBB handover, since the UE is connected to both the source BS and the target BS, the UE needs to monitor and receive downlink control information (DCI) related to the source cell and the target cell from both the source BS and the target BS, respectively. This means that the UE should be able to monitor the PDCCH associated with each of the source cell and the target cell. Several factors need to be considered when deciding how the UE monitors the PDCCH of two different cells.

[0047] For example, 3GPP Release 15 allows only 3 control resource sets (CORSETs or CORESETs) per downlink bandwidth part (BWP) for the serving cell. Therefore, most UEs generally support monitoring of up to 3 CORSETs for a given active BWP assigned to the UE. Now, if the UE were to monitor the PDCCH for two different cells, this would mean that the UE might have to monitor 6 different CORSETs (3 CORSETs per cell) for a given active BWP. However, the UE might only support up to 3 active CORESETs at a time, and therefore, the UE might not be able to monitor all CORSETs configured for each of the two cells.

[0048] In some cases, the PDCCH opportunities of the source cell and the target cell may overlap, and the CORSETs corresponding to each of the two cells may be transmitted in the same PDCCH opportunity (e.g., at different frequency locations of the same PDCCH opportunity). In addition, different beams are generally used to transmit different CORSETs. The UE can generally monitor only one beam at a time. Therefore, in the case where the PDCCH opportunities of the two cells overlap, the UE can monitor the CORSET corresponding to only one beam in a given PDCCH opportunity, and cannot monitor two different CORSETs corresponding to the two different cells.

[0049] The current standard defines that in case of overlapping PDCCH opportunities, the beam with the lowest index is selected and the PDCCH corresponding to the selected beam is monitored. However, this rule does not take into account which of these cells may actually need to be prioritized based on various factors.

[0050] Certain aspects of the present disclosure discuss techniques for a UE to monitor two different PDCCHs associated with two different cells when the UE is simultaneously connected to the two cells (e.g., during MBB handover). The techniques discussed include defining configurations that the UE can use to monitor the PDCCH for the two cells, wherein the configurations are defined so that the UE can effectively monitor the PDCCH of the two cells while remaining within the constraints mentioned above.

[0051] Figure 4 4 illustrates example operations 400 for a UE to monitor physical downlink control channel (PDCCH) transmissions (eg, conveying DCI) for two different cells in accordance with certain aspects of the present disclosure. For example, operations 400 may be performed by Figure 1 or Figure 2 UE 120 is used to execute.

[0052] The operations 400 begin at 402 by determining a first number of control resource sets (CORESETs) to monitor in a source cell when a UE is maintaining connectivity with both the source cell and the target cell during a handover procedure.

[0053] At 404, the UE determines a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure.

[0054] At 406, the UE monitors Physical Downlink Control Channel (PDCCH) transmissions in a first number of CORESETs in the source cell and a second number of CORESETs in the target cell during the handover procedure.

[0055] Figure 5 Explains what can be considered Figure 4 Example operations 500 complementary to operations 400 of the present invention. For example, operations 500 may be performed by a network entity (e.g., a central unit (CU) of a source and / or target gNB) to configure a UE to perform operations 400.

[0056] Operations 500 begin at 502 by configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to monitor in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure.

[0057] At 504, the network entity configures the UE with a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure.

[0058] In certain aspects, the configuration for monitoring cells during MBB handover is determined by one of the source gNB, the target gNB, or a network entity and communicated to the UE.

[0059] In some cases, the UE may receive (broadcast or unicast) signaling that configures the minimum number of CORESETs that the UE is allowed to monitor in each of the target cell and the source cell. In such cases, the UE may determine the first number of CORESETs and the second number of CORESETs that comply with the configured minimum number.

[0060] The UE may also receive signaling that configures the maximum number of CORESETs that the UE is allowed to monitor in total in the target cell and the source cell. In such a scenario, the UE may determine a first number of CORESETs and a second number of CORESETs that also comply with the configured maximum number. For example, the UE may determine that the sum of the minimum number of CORESETs that the UE is allowed to monitor in the target cell and the minimum number of CORESETs that the UE is allowed to monitor in the source cell is less than the configured maximum number, and may decide based on a priority rule whether to assign the remaining number of CORESETs obtained after subtracting the sum from the configured maximum number to the target cell or the source cell. For example, the priority rule may specify that one or more of the remaining number of CORESETs be assigned to the target cell.

[0061] In some cases, the UE may detect an overlap of monitoring opportunities in different CORESETs associated with different beams, and if the UE is not configured to support different beams simultaneously, decide which of the overlapping monitoring opportunities to monitor based on the discarding rules. In some cases, the UE may receive signaling that configures the UE with priority information to be used when applying the discarding rules.

[0062] In some cases, the priority information may assign a priority to at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell.

[0063] In some cases, the priority information may assign priority to at least one of the following within the same cell: USS over CSS or CSS over USS. In such cases, the priority information may also prioritize the target cell over the source cell or the source cell over the target cell.

[0064] In some cases, the UE may send a request for a drop rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell. In such cases, the UE may receive a response to the request and monitor overlapping CORESETs according to the drop rule indicated in the response.

[0065] In some cases, where a CORESET overlaps with another CORESET in a monitoring occasion, the UE may utilize the beam of the prioritized CORESET as the default beam.

[0066] In some cases, such as Figure 6As shown in , the PDCCH opportunities for the source cell (shown as Cell 1) and the target cell (shown as Cell 2) may overlap. In this case, different CORSETs corresponding to each of the source cell and the target cell may be transmitted in the same PDCCH opportunity using different beams. As mentioned above, the UE may be able to monitor only one beam at a time. Since the CORSETs monitored by the UE for different cells may be associated with different beams, if two PDCCH monitoring opportunities overlap, the UE may not be able to monitor these two PDCCH monitoring opportunities. In such a situation, the UE needs to select one of the two cells for monitoring while discarding the other cell. On the one hand, a cell with a higher assigned priority may be selected for monitoring, while a cell with a lower priority may be discarded. On the one hand, the TCI state (beam) of the prioritized cell becomes the default beam for the PDCCH opportunity in the case of overlap.

[0067] Aspects of the present disclosure may allow a UE to decide which CORESET to monitor in such overlapping scenarios.

[0068] Figure 7 700 illustrates example operations 700 for a UE to monitor physical downlink control channel (PDCCH) transmissions (eg, conveying DCI) for two different cells in accordance with certain aspects of the present disclosure. For example, operations 700 may be performed by Figure 1 or Figure 2 UE 120 is used to execute.

[0069] Operations 700 begin at 702 by determining a number of control resource sets (CORESETs) for the UE to monitor when the UE is maintaining connectivity with both a source cell and a target cell during a handover procedure.

[0070] At 704, the UE may decide, based on a dropping rule, which of the overlapping monitoring opportunities to monitor in a situation where monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0071] At 706, the UE monitors Physical Downlink Control Channel (PDCCH) transmissions according to the decision during the handover procedure.

[0072] Figure 8 Explains what can be considered as Figure 7 Example operations 800 complementary to operations 700 of the present invention. For example, operations 800 may be performed by a network entity (e.g., a central unit (CU) of a source and / or target gNB) to configure the UE to perform operations 700.

[0073] Operations 800 begin at 802 by configuring a user equipment (UE) with a number of control resource sets (CORESETs) to monitor when the UE is maintaining connectivity with both a source cell and a target cell during a handover procedure.

[0074] At 804, the network entity may configure a dropping rule for the UE to decide which of the overlapping monitoring opportunities to monitor in a situation where monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0075] In some cases, the UE may receive signaling that configures the UE with priority information to be used when applying discard rules.

[0076] In some cases, the priority information may assign a priority to at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell.

[0077] In some cases, the priority information may assign priority to at least one of the following within the same cell: USS over CSS or CSS over USS. In such cases, the priority information may also prioritize the target cell over the source cell or the source cell over the target cell.

[0078] In some cases, the UE may send a request for a drop rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell. In such cases, the UE may receive a response to the request and monitor overlapping CORESETs according to the drop rule indicated in the response.

[0079] In some cases, where a CORESET overlaps with another CORESET in a monitoring occasion, the UE may utilize the beam of the prioritized CORESET as the default beam.

[0080] In certain aspects, a priority associated with at least one of the first cell or the second cell is determined based on at least one of: a type of communication between the UE and each of the source gNB and the target gNB, or a signal strength between the UE and each of the source gNB and the target gNB. A configuration for monitoring the PDCCH of the two cells is then determined based on the determined priority of at least one of the two cells. In one aspect, more system resources are assigned to cells with higher priority. These system resources may include: a number of CORSETs and / or search spaces (including USSs and CSSs) that the UE can monitor for a particular cell, an amount of UE communication and processing resources to be used to monitor DCI for a particular cell, or any other resources that may facilitate a hitless or near hitless switching of the UE from the source cell to the target cell.

[0081] In one aspect, monitoring a higher number of CORSETs for a particular cell increases the chance that the UE successfully receives the PDCCH for the cell. Different CORESETs generally use different beams for transmission. Different beams may experience different channel conditions, for example, based on the specific time and frequency resources used for the beam. Assigning a higher number of CORESETs to a particular cell may increase the chance that the UE successfully receives one or more assigned CORSETs on the corresponding beam with favorable channel conditions, even if the channel conditions for the beams used to transmit one or more other CORSETs assigned to the same cell are unfavorable. Additionally or alternatively, assigning a higher number of UE resources for monitoring the PDCCH of a particular cell may increase the chance that the UE successfully receives the PDCCH for the cell. For example, the UE may be able to monitor only one beam at a time. Therefore, during MBB switching, when the PDCCH opportunities of the source cell and the target cell overlap, the UE radio frequency (RF) chain may be assigned based on the priority values ​​of the two cells to monitor the beam corresponding to one of the two cells. For example, the RF chain of the UE may be assigned to a cell with a higher assigned priority. It may be noted that the examples of system resources discussed herein are not meant to be an exhaustive list of resources that may be assigned for monitoring DCI of a source cell and a target cell based on the priority of the cells. Any resources that may facilitate a hitless or near hitless handover of the UE from the source cell to the target cell may be assigned to each of these cells based on the priority of the cells.

[0082] In some aspects, priorities may be assigned to the source cell and the target cell based on the current stage of the handover, the signal strength associated with the communication between the UE and each of the source gNB and the target gNB, or a combination thereof. For example, by default, when a decision is made (e.g., by an NR core network entity such as a CU) to handover the UE from the source cell to the target cell, a higher priority may be assigned to the target cell than to the source cell. In this way, once the handover decision is made, more resources may be assigned to monitor the PDCCH of the target cell to ensure that the handover is completed efficiently and as quickly as possible. In one aspect, additionally or alternatively, priorities may be assigned based on the signal strength associated with the communication between the UE and each of the source gNB and the target gNB. For example, a link with a higher signal strength is assigned a higher priority. In some cases, a decision to handover the UE from the source cell to the target cell is generally made when the signal strength of the link between the UE and the source gNB drops below a threshold signal strength and / or when the signal strength of the link between the UE and the target gNB exceeds a threshold signal strength. For example, when the signal strength of the link between the UE and the target gNB exceeds a threshold signal strength, there is a high probability that the UE can successfully switch to the target cell. In this case, a higher priority can be assigned to the target cell, and more resources can be used to monitor the DCI of the target cell. On the other hand, if the signal strength of the target gNB link drops below the threshold, and the signal strength of the source gNB link has not deteriorated too much, a higher priority can be assigned to the source cell, and more resources can be assigned to monitor the source cell to ensure that the UE can continue to communicate with the source cell in the event that the switch to the target is unsuccessful. On the one hand, the priorities of the source cell and the target cell can be dynamically assigned based on the signal strength of the link between the UE and each of the source gNB and the target gNB. The resources assigned to each of the source cell and the target cell can be dynamically adjusted as the cell priorities change.

[0083] In one aspect, the signal strength may be indicated by a value of Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) as measured by the UE. In one aspect, the UE reports to one of the source gNB or the target gNB information regarding the signal strength of the link between the UE and each of the source gNB and the target gNB. The receiving gNB determines a priority of the cells based on the received link signal strengths and determines a configuration for the UE to monitor the DCI for the two cells.

[0084] In certain aspects, priorities may be assigned to the source cell and the target cell based on the stage of the handover from the source cell to the target cell. In one aspect, the stage of the handover may be indicated by the type of ongoing communication between the UE and each of the source gNB and the target gNB. For example, when the UE is actively exchanging data (e.g., PDSCH data) with the source gNB and is receiving common control signaling (e.g., by monitoring the CSS of the CORSET assigned to the target cell), this indicates that the handover is in an initial stage where the UE is attempting to establish a connection with the target and is still relying on the source for data communications. At this stage, the link between the UE and the target gNB may be good (e.g., the signal strength exceeds a threshold), and therefore, the target cell may be assigned a slightly higher priority than the source cell. Based on the higher priority of the target, a greater number of resources may be assigned to monitor the target cell. In one aspect, when the UE is in the late stages of establishing a connection with the target (as indicated by signaling exchanged between the UE and the target), indicating a high likelihood of a successful handover, the target cell may be assigned an even higher priority value so that more resources are assigned to the target cell. Thus, the amount of resources assigned to a particular cell may be a function of the priority value assigned to that cell, with higher priority values ​​resulting in more resources being assigned to that cell.

[0085] In certain aspects, a minimum number of CORSETs may be assigned to each of the source cell and the target cell. Thus, for each of the cells, the UE monitors at least the minimum number of CORSETs assigned to the cell. In one aspect, the total number of CORSETs to be monitored by the UE does not exceed the maximum number of active CORSETs (N) that the UE can monitor per BWP. For example, if M1 represents the minimum number of CORSETs assigned to the source cell, and M2 is the minimum number of CORSETs assigned to the target cell, then M1+M2<=N. In one aspect, the values ​​of M1 and M2 are communicated to the UE via RRC signaling. In one aspect, the values ​​of M1 and M2 may be fixed and known to the UE. In one example, assuming N=3, the minimum number of CORSETs that can be assigned to the cell may be Mi=0, 1, or 2. For example, a higher priority may be assigned to the target cell by default, and a higher minimum number of CORSETs to be monitored may be assigned to the target cell (e.g., M2=2).

[0086] In certain aspects, the UE may support monitoring a maximum number (N) of active CORSETs for a given BWP that is higher than the sum of the minimum number of CORSETs assigned to the source cell and the target cell (M1+M2). In such a scenario, the remaining N-(M1+M2) CORSETs may be assigned to the source cell and the target cell based on the priority values ​​of the cells.

[0087] In one aspect, the CORSET configuration transmitted to the UE includes a specific CORSET that the UE is to monitor for each cell. In one aspect, the number of CORSETs assigned to each of the source cell and the target cell can be dynamically determined based on the priority value of the cell. These changed numbers can be dynamically signaled to the UE.

[0088] Example Embodiments

[0089] Embodiment 1: A method for wireless communication by a user equipment (UE), comprising: determining a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; determining a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during the switching procedure; and monitoring physical downlink control channel (PDCCH) transmissions in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the switching procedure.

[0090] Embodiment 2: The method of embodiment 1 further comprises: receiving signaling that configures a minimum number of CORESETs that the UE is allowed to monitor in each of the target cell and the source cell; and determining a first number of CORESETs and a second number of CORESETs that comply with the configured minimum number.

[0091] Embodiment 3: The method of embodiment 2 further comprises: receiving signaling that configures a maximum number of CORESETs that the UE is allowed to monitor in total in the target cell and the source cell; and determining a first number of CORESETs and a second number of CORESETs that also comply with the configured maximum number.

[0092] Embodiment 4: The method of embodiment 3 further comprises: determining that the sum of the minimum number of CORESETs that the UE is allowed to monitor in the target cell and the minimum number of CORESETs that the UE is allowed to monitor in the source cell is less than the configured maximum number; and

[0093] A decision is made based on priority rules as to whether the remaining number of CORESETs obtained after subtracting the sum from the configured maximum number is to be assigned to the target cell or the source cell.

[0094] Embodiment 5: The method of embodiment 4, wherein the priority rule stipulates that one or more CORESETs among the remaining number of CORESETs are assigned to the target cell.

[0095] Embodiment 6: A method as in any one of embodiments 1-5, further comprising: detecting an overlap of monitoring opportunities in different CORESETs associated with different beams; and if the UE is not configured to support different beams simultaneously, deciding which of the overlapping monitoring opportunities to monitor based on a discarding rule.

[0096] Embodiment 7: The method of embodiment 6 further includes receiving signaling, which configures the UE with priority information to be used when applying the discard rule.

[0097] Embodiment 8: The method of embodiment 7, wherein the priority information assigns priority to at least one of: a UE-specific search space (USS) relative to a common search space (CSS); or a target cell relative to a source cell.

[0098] Embodiment 9: The method of any one of embodiments 1-8, wherein the priority information assigns priority within the same cell to at least one of: USS over CSS; or CSS over USS.

[0099] Embodiment 10: The method as in embodiment 9, wherein the priority information further: gives priority to the target cell over the source cell; or gives priority to the source cell over the target cell.

[0100] Embodiment 11: The method of any one of Embodiments 1-10, wherein the priority information further: prioritizes the target cell over the source cell; or prioritizes the source cell over the target cell.

[0101] Embodiment 12: A method as in any one of embodiments 1-11, further comprising: sending a request for a discard rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell; receiving a response to the request; and monitoring overlapping CORESETs according to the discard rule indicated in the response.

[0102] Embodiment 13: The method of any one of embodiments 1-10, further comprising utilizing a beam of a prioritized CORESET as a default beam in a situation where a CORESET overlaps with another CORESET in a monitoring occasion.

[0103] Embodiment 14: A method for wireless communication by a network entity, comprising: configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; and configuring the UE with a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure.

[0104] Embodiment 15: The method of Embodiment 14, wherein configuring the first number and the second number of CORESETs for the UE comprises configuring the UE with a minimum number of CORESETs that the UE is allowed to monitor in each of the target cell and the source cell.

[0105] Embodiment 16: The method of embodiment 15, wherein configuring the first number and the second number of CORESETs for the UE further comprises configuring the UE with a maximum number of CORESETs that the UE is allowed to monitor in total in the target cell and the source cell.

[0106] Embodiment 17: A method as in any one of Embodiments 14-17, further comprising configuring a discarding rule for the UE to decide which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0107] Embodiment 18: A method as in Embodiment 17, wherein configuring discarding rules for the UE includes configuring priority information for the UE to be used when applying the discarding rules.

[0108] Embodiment 19: The method of Embodiment 18, wherein the priority information assigns priority to at least one of: a UE-specific search space (USS) relative to a common search space (CSS); or a target cell relative to a source cell.

[0109] Embodiment 20: The method of any one of embodiments 14-19, wherein the priority information assigns priority within the same cell to at least one of: USS over CSS; or CSS over USS.

[0110] Embodiment 21: A method as in Embodiment 20, wherein the priority information further: gives priority to the target cell over the source cell; or gives priority to the source cell over the target cell.

[0111] Embodiment 22: A method as in any one of embodiments 14-21, further comprising: receiving a request for a discard rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell; and configuring the discard rule for the UE in response to the request.

[0112] Embodiment 23: A method for wireless communication by a user equipment (UE), comprising: determining the number of control resource sets (CORESETs) to be monitored by the UE when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; deciding, based on a discard rule, which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously; and monitoring a physical downlink control channel (PDCCH) transmission during the switching procedure according to the decision.

[0113] Embodiment 24: The method of embodiment 23 further includes receiving signaling that configures the UE with priority information to be used when applying discard rules.

[0114] Embodiment 25: The method of embodiment 24, wherein the priority information assigns priority to at least one of: a UE-specific search space (USS) relative to a common search space (CSS); or a target cell relative to a source cell.

[0115] Embodiment 26: The method of any one of Embodiments 23-25, wherein the priority information assigns priority within the same cell to at least one of: USS over CSS; or CSS over USS.

[0116] Embodiment 27: A method as in Embodiment 26, wherein the priority information further: gives priority to the target cell over the source cell; or gives priority to the source cell over the target cell.

[0117] Embodiment 28: The method of any one of Embodiments 23-27, wherein the priority information further: prioritizes the target cell over the source cell; or prioritizes the source cell over the target cell.

[0118] Embodiment 29: A method as in any one of embodiments 23-28, further comprising: sending a request for a discard rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell; receiving a response to the request; and monitoring overlapping CORESETs according to the discard rule indicated in the response.

[0119] Embodiment 30: The method of any one of Embodiments 23-29, further comprising utilizing a beam of a prioritized CORESET as a default beam in a situation where a CORESET overlaps with another CORESET in a monitoring occasion.

[0120] Embodiment 31: A method for wireless communication by a network entity, comprising: configuring a user equipment (UE) with the number of control resource sets (CORESETs) to be monitored when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; and configuring a discarding rule for the UE to decide which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0121] Embodiment 32: A method as in Embodiment 31, wherein configuring discarding rules for the UE includes configuring priority information for the UE to be used when applying the discarding rules.

[0122] Embodiment 33: The method of embodiment 32, wherein the priority information assigns priority to at least one of: a UE-specific search space (USS) relative to a common search space (CSS); or a target cell relative to a source cell.

[0123] Embodiment 34: The method of embodiment 33, wherein the priority information assigns priority to at least one of the following within the same cell: USS over CSS; or CSS over USS.

[0124] Embodiment 35: A method as in embodiment 34, wherein the priority information further: gives priority to the target cell over the source cell; or gives priority to the source cell over the target cell.

[0125] Embodiment 36: A method as in any one of embodiments 31-35, further comprising: receiving a request for a discard rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or a target cell relative to a source cell; and configuring the discard rule for the UE in response to the request.

[0126] Embodiment 37: An apparatus for wireless communications by a user equipment (UE), comprising: a device for determining a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; a device for determining a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; and a device for monitoring physical downlink control channel (PDCCH) transmissions in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the switching procedure.

[0127] Embodiment 38: A device for wireless communication by a network entity, comprising: a device for configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; and a device for configuring the UE with a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure.

[0128] Embodiment 39: A device for wireless communication by a user equipment (UE), comprising: a device for determining the number of control resource sets (CORESETs) to be monitored by the UE when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; a device for deciding, based on a discard rule, which of the overlapping monitoring opportunities to monitor in a situation where monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously; and a device for monitoring a physical downlink control channel (PDCCH) transmission during the switching procedure based on the decision.

[0129] Embodiment 40: A device for wireless communication by a network entity, comprising: a device for configuring a user equipment (UE) with the number of control resource sets (CORESETs) to be monitored when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; and a device for configuring a discarding rule for the UE to decide which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0130] Embodiment 41: An apparatus for wireless communication by a user equipment (UE), comprising: at least one processor and a memory, wherein the at least one processor and the memory are configured to: determine a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; determine a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during the switching procedure; and monitor physical downlink control channel (PDCCH) transmissions in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the switching procedure.

[0131] Embodiment 42: An apparatus for wireless communication by a network entity, comprising: at least one processor and a memory, wherein the at least one processor and the memory are configured to: configure a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; and configure the UE with a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure.

[0132] Embodiment 43: An apparatus for wireless communication by a user equipment (UE), comprising: at least one processor and a memory, the at least one processor and the memory being configured to: determine the number of control resource sets (CORESETs) to be monitored by the UE when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; decide based on a discard rule which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously; and monitor a physical downlink control channel (PDCCH) transmission according to the decision during the switching procedure.

[0133] Embodiment 44: An apparatus for wireless communication by a network entity, comprising: at least one processor and a memory, the at least one processor and the memory being configured to: configure a user equipment (UE) with the number of control resource sets (CORESETs) to be monitored when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; and configure a discarding rule for the UE to decide which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0134] Embodiment 45: A computer-readable medium having stored thereon instructions for: determining a first number of control resource sets (CORESETs) to be monitored in a source cell when a user equipment (UE) is maintaining connectivity with both the source cell and the target cell during a switching procedure; determining a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during the switching procedure; and monitoring physical downlink control channel (PDCCH) transmissions in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the switching procedure.

[0135] Embodiment 46: A computer-readable medium having stored thereon instructions for: configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure; and configuring the UE with a second number of CORESETs to be monitored in a target cell when the UE is maintaining connectivity with both the source cell and the target cell during a switching procedure.

[0136] Embodiment 47: A computer-readable medium having stored thereon instructions for: determining the number of control resource sets (CORESETs) to be monitored by a user equipment (UE) when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; deciding, based on a discard rule, which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously; and monitoring a physical downlink control channel (PDCCH) transmission according to the decision during the switching procedure.

[0137] Embodiment 48: A computer-readable medium having stored thereon instructions for: configuring a user equipment (UE) with the number of control resource sets (CORESETs) to be monitored when the UE is maintaining connectivity with both a source cell and a target cell during a switching procedure; and configuring a discarding rule for the UE to decide which of the overlapping monitoring opportunities to monitor when monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

[0138] The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDMA, etc. UTRA and E-UTRA are parts of Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is an emerging wireless communication technology under development.

[0139] The techniques described herein can be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, although various aspects may be described herein using terms commonly associated with 3G, 4G and / or 5G wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations.

[0140] In 3GPP, the term "cell" may refer to the coverage area of ​​a B node (NB) and / or a NB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and BS, next-generation B node (gNB or g B node), access point (AP), distributed unit (DU), carrier, or transmission reception point (TRP) may be used interchangeably. The BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a radius of several thousand meters) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a residence, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0141] UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical equipment, biometric sensor / device, wearable device (such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), transportation component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity for or to a network (e.g., a wide area network (such as the Internet) or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0142] Some wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also often referred to as frequency modulation, frequency bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain for OFDM and in the time domain for SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of subcarriers can be 15kHz, and the minimum resource allocation (called a "resource block" (RB)) can be 12 subcarriers (or 180kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth may also be divided into subbands. For example, a subband may cover 1.08 MHz (e.g., 6 RBs), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0143] NR can utilize OFDM with CP on the uplink and downlink and includes support for half-duplex operation using TDD. In NR, the subframe is still 1ms, but the basic TTI is called a time slot. The subframe contains a variable number of time slots (e.g., 1, 2, 4, 8, 16...time slots), which depends on the subcarrier spacing. NR RB is 12 consecutive frequency subcarriers. NR can support a base subcarrier spacing of 15KHz, and other subcarrier spacings can be defined relative to the base subcarrier spacing, such as 30kHz, 60kHz, 120kHz, 240kHz, etc. The symbol and time slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming can be supported and the beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. In some examples, the MIMO configuration in the DL can support up to 8 transmit antennas (multi-layer DL transmission with up to 8 streams) and up to 2 streams per UE. In some examples, multi-layer transmission of up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported using up to 8 serving cells.

[0144] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., BS) allocates resources for communication between some or all devices and equipment within its service area or cell. A scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, subordinate entities utilize resources allocated by the scheduling entity. A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity, and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize resources scheduled by the UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In a mesh network example, UEs may communicate directly with each other in addition to communicating with a scheduling entity.

[0145] In some examples, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh networks, and / or various other suitable applications. Generally, a sidelink signal may refer to a signal that is communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., UE or BS), even if the scheduling entity may be used for scheduling and / or control purposes. In some examples, the sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0146] Each method disclosed herein includes one or more steps or actions for implementing the method. These method steps and / or actions can be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be changed without departing from the scope of the claims.

[0147] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0148] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Also, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0149] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be easily understood by those skilled in the art, and the universal principles defined herein can be applied to other aspects. Thus, the claims are not intended to be limited to the various aspects shown herein, but should be granted the full scope consistent with the language of the claims, wherein the singular reference to the element is not intended to mean "there is and only one" (unless specifically stated) but "one or more". Unless otherwise specifically stated, the term "some / some" refers to one or more. The elements of the various aspects described throughout this disclosure are all structural and functional equivalents currently or hereafter known to those of ordinary skill in the art and are expressly incorporated herein by reference, and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be donated to the public, regardless of whether such disclosure is explicitly recorded in the claims. Any element of the claim should not be interpreted under the provisions of 35 U.S.C. § 112 (f), unless the element is explicitly stated using the phrase "device for..." or in the case of a method claim, the element is stated using the phrase "step for...".

[0150] The various operations of the methods described above may be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Generally, where there are operations illustrated in the accompanying drawings, these operations may have corresponding paired device-plus-function components with similar numbers.

[0151] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0152] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter, etc., to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the user terminal 120 (see Figure 1 ), a user interface (e.g., a keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art and will not be described further. The processor may be implemented with one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuit systems capable of executing software. Those skilled in the art will recognize how to best implement the functionality described with respect to the processing system, depending on the specific application and the overall design constraints imposed on the overall system.

[0153] If implemented in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, which include any media that facilitate the transfer of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. As an example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon that is separated from a wireless node, all of which may be accessed by a processor through a bus interface. Alternatively or additionally, a machine-readable medium or any part thereof may be integrated into a processor, such as a cache and / or a general register file, which may be the case. As an example, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read only memory), PROM (programmable read only memory), EPROM (erasable programmable read only memory), EEPROM (electrically erasable programmable read only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be implemented in a computer program product.

[0154] A software module may include a single instruction, or many instructions, and may be distributed over several different code segments, distributed between different programs, and distributed across multiple storage media. A computer-readable medium may include several software modules. These software modules include instructions that cause a processing system to perform various functions when executed by an apparatus such as a processor. These software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or may be distributed across multiple storage devices. As an example, when a triggering event occurs, a software module may be loaded into a RAM from a hard drive. During the execution of a software module, a processor may load some instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When describing the functionality of a software module as described below, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0155] Likewise, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology (such as infrared (IR), radio, and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Disks, where disks often reproduce data magnetically, and discs reproduce data optically with lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0156] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having stored (and / or encoded) thereon instructions that can be executed by one or more processors to perform the operations described herein, such as for performing the operations described herein and in Figure 4 Instructions for the operations explained in .

[0157] In addition, it should be appreciated that modules and / or other appropriate means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by a user terminal and / or base station where applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk, etc.) so that once the storage device is coupled to or provided to a user terminal and / or base station, the device can obtain the various methods. In addition, any other suitable technology suitable for providing the methods and techniques described herein to a device may be utilized.

[0158] It will be understood that the claims are not limited to the precise configuration and components illustrated above. Various changes, substitutions and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a user equipment (UE), comprising: determining a first number of control resource sets (CORESETs) to monitor in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; determining a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure; as well as Physical Downlink Control Channel (PDCCH) transmissions are monitored in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the handover procedure.

2. The method of claim 1, further comprising: receiving signaling configuring a minimum number of CORESETs that the UE is allowed to monitor in each of the target cell and the source cell; as well as A first number of the CORESETs and a second number of the CORESETs that comply with a configured minimum number are determined.

3. The method of claim 2, further comprising: receiving signaling that configures a maximum number of CORESETs that the UE is allowed to monitor in total in the target cell and the source cell; as well as The determination is also subject to the first number of CORESETs and the second number of CORESETs being in compliance with a configured maximum number.

4. The method of claim 3, further comprising: determining that a sum of a minimum number of CORESETs that the UE is allowed to monitor in the target cell and a minimum number of CORESETs that the UE is allowed to monitor in the source cell is less than the configured maximum number; as well as A decision is made based on a priority rule as to whether a remaining number of CORESETs obtained after subtracting the sum from the configured maximum number is to be assigned to the target cell or the source cell.

5. The method of claim 4, wherein the priority rule provides that one or more CORESETs of the remaining number of CORESETs are assigned to the target cell.

6. The method of claim 1, further comprising: Detecting overlap of monitoring opportunities in different CORESETs associated with different beams; as well as If the UE is not configured to support different beams simultaneously, it is decided which of the overlapping monitoring occasions to monitor based on a dropping rule.

7. The method of claim 6, further comprising receiving signaling that configures the UE with priority information to be used when applying the discard rule.

8. The method of claim 7, wherein the priority information assigns a priority to at least one of: A UE-specific search space (USS) relative to a common search space (CSS); or The target cell relative to the source cell.

9. The method of claim 7, wherein the priority information assigns priority to at least one of: USS takes precedence over CSS; or CSS takes precedence over USS.

10. The method of claim 9, wherein the priority information further: prioritizing the target cell over the source cell; or The source cell is prioritized over the target cell.

11. The method of claim 7, wherein the priority information further: prioritizing the target cell over the source cell; or The source cell is prioritized over the target cell.

12. The method of claim 6, further comprising: sending a request for a specific drop rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or the target cell relative to the source cell; receiving a response to the request; as well as The overlapping CORESETs are monitored according to the discarding rules indicated in the response.

13. The method of claim 6, further comprising: In the case where a CORESET overlaps with another CORESET in a monitoring occasion, the beam of the prioritized CORESET is utilized as the default beam.

14. A method for wireless communication by a network entity, comprising: configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to monitor in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; as well as The UE is configured with a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure.

15. The method of claim 14, wherein configuring the first number and the second number of the CORESETs for the UE comprises configuring the UE with a minimum number of CORESETs that the UE is allowed to monitor in each of the target cell and the source cell.

16. The method of claim 15, wherein configuring the first number and the second number of the CORESETs for the UE further comprises configuring the UE with a maximum number of CORESETs that the UE is allowed to monitor in total in the target cell and the source cell.

17. The method of claim 14, further comprising configuring a discarding rule for the UE to decide which of the overlapping monitoring opportunities to monitor in a situation where monitoring opportunities in different CORESETs associated with different beams overlap and the UE is not configured to support different beams simultaneously.

18. The method of claim 17, wherein configuring the discard rule for the UE comprises configuring priority information for the UE to be used when applying the discard rule.

19. The method of claim 18, wherein the priority information assigns a priority to at least one of: A UE-specific search space (USS) relative to a common search space (CSS); or The target cell relative to the source cell.

20. The method of claim 18, wherein the priority information assigns priority within the same cell to at least one of: USS takes precedence over CSS; or CSS takes precedence over USS.

21. The method of claim 20, wherein the priority information further: prioritizing the target cell over the source cell; or The source cell is prioritized over the target cell.

22. The method of claim 17, further comprising: receiving a request for a specific dropping rule that prioritizes at least one of: a UE-specific search space (USS) relative to a common search space (CSS) or the target cell relative to the source cell; and In response to the request, the discard rule is configured for the UE.

23. An apparatus for wireless communication by a user equipment (UE), comprising: means for determining a first number of control resource sets (CORESETs) to monitor in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; means for determining a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure; as well as Means for monitoring Physical Downlink Control Channel (PDCCH) transmissions in a first number of CORESETs in the source cell and a second number of CORESETs in the target cell during the handover procedure.

24. The apparatus of claim 23, further comprising means for performing any of claims 2-13.

25. An apparatus for wireless communication by a network entity, comprising: means for configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; as well as Means for configuring the UE with a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure.

26. The apparatus of claim 25, further comprising means for performing any of claims 15-22.

27. An apparatus for wireless communication by a user equipment (UE), comprising: at least one processor and a memory, the at least one processor and the memory being configured to: determining a first number of control resource sets (CORESETs) to monitor in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; determining a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure; as well as Physical Downlink Control Channel (PDCCH) transmissions are monitored in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the handover procedure.

28. An apparatus for wireless communication by a network entity, comprising: at least one processor and a memory, the at least one processor and the memory being configured to: configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to monitor in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; as well as The UE is configured with a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure.

29. A computer readable medium having stored thereon instructions for: determining a first number of control resource sets (CORESETs) to monitor in a source cell when a user equipment (UE) is maintaining connectivity with both the source cell and the target cell during a handover procedure; determining a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure; as well as Physical Downlink Control Channel (PDCCH) transmissions are monitored in the first number of CORESETs in the source cell and the second number of CORESETs in the target cell during the handover procedure.

30. A computer readable medium having stored thereon instructions for: configuring a user equipment (UE) with a first number of control resource sets (CORESETs) to be monitored in a source cell when the UE is maintaining connectivity with both the source cell and the target cell during a handover procedure; and The UE is configured with a second number of CORESETs to monitor in the target cell when the UE is maintaining connectivity with both the source cell and the target cell during the handover procedure.

Images