Multi-cell synchronization for dual connectivity and carrier aggregation

Abstract

Techniques and apparatuses are described for achieving multi-cell synchronization for dual connectivity and carrier aggregation. In one technique, a timing difference between a first base station (BS) and a second BS is determined, where the first BS is in an asynchronous timing configuration with respect to the second BS. A measurement configuration for measuring a signal(s) from the second BS is determined based on the timing difference. The measurement configuration is signaled to a user equipment (UE) served by the first BS. The UE performs a measurement procedure for the signal(s) in accordance with the measurement configuration. In another technique, the second BS receives a synchronization request from the first BS via a network interface between the first BS and the second BS, the synchronization request including a first timestamp. The second BS sends a synchronization response to the first BS, the synchronization response including a second timestamp.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit and priority of Patent Cooperation Treaty application No. PCT / CN2020 / 071309, filed on January 10, 2020, which has been assigned to the assignee of this application and is hereby expressly incorporated by reference.

[0003] background

[0004] I. Open Domain

[0005] Various aspects of this disclosure relate to wireless communications, and more particularly to techniques for performing multi-cell synchronization for dual connectivity (DC) scenarios and / or carrier aggregation (CA) scenarios.

[0006] II. Related Technical Description

[0007] Wireless communication systems are widely deployed to provide a variety of telecommunications services such as telephone, video, data, messaging, and broadcasting. These wireless communication systems can employ multiple access technologies that enable communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 3GPP Long Term Evolution (LTE) systems, LTE-A Advanced 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.

[0008] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, country, region, and even global levels. New radios (e.g., 5G NR) are examples of emerging telecommunications standards. NR is an enhancement set of the LTE mobile standard issued by 3GPP. NR is designed to better support mobile broadband Internet access by using OFDMA with a cyclic prefix (CP) on both the downlink (DL) and uplink (UL) to improve spectrum efficiency, reduce costs, improve service, utilize new spectrum, and better integrate with other open standards. To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0009] However, with the continued growth in demand for mobile broadband access, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multiple access technologies and telecommunications standards that employ these technologies.

[0010] Overview

[0011] The systems, methods, and apparatus of this disclosure each have several aspects, and their desired properties are not solely the responsibility of any single aspect. Without limiting the scope of this disclosure as set forth in the appended claims, some features will now be briefly discussed. Upon consideration of this discussion, and especially after reading the section entitled “Detailed Description,” it will be understood how the features of this disclosure provide advantages including improved measurements of adjacent cells.

[0012] Some aspects provide a method for wireless communication that can be performed by a first base station (BS). The method generally includes determining a timing difference between the first BS and one or more second BSs. The first BS is in an asynchronous timing configuration relative to the one or more second BSs. The method also includes determining a measurement configuration for measuring one or more signals from the one or more second BSs, based at least in part on the timing difference between the first BS and the one or more second BSs. The method further includes signaling the measurement configuration to user equipment (UE) served by the first BS.

[0013] Some aspects provide an apparatus for wireless communication. The apparatus generally includes at least one processor, a memory coupled to the at least one processor, and a transmitter. The at least one processor is configured to determine a timing difference between the apparatus and one or more BSs. The apparatus is in an asynchronous timing configuration relative to the one or more BSs. The at least one processor is also configured to determine a measurement configuration for measuring one or more signals from the one or more BSs, based at least in part on the timing difference between the apparatus and the one or more BSs. The transmitter is configured to transmit the measurement configuration to user equipment (UE) served by the apparatus.

[0014] Some aspects provide an apparatus for wireless communication. The apparatus generally includes means for determining a timing difference between the apparatus and one or more BSs. The apparatus is in an asynchronous timing configuration relative to the one or more BSs. The apparatus also includes means for determining a measurement configuration for measuring one or more signals from the one or more BSs, based at least in part on the timing difference between the apparatus and the one or more BSs. The apparatus further includes means for signaling the measurement configuration to user equipment (UE) served by the apparatus.

[0015] Some aspects provide a computer-readable medium having stored thereon computer-executable code for wireless communication by a first BS. The computer-executable code generally includes code for determining a timing difference between the first BS and one or more second BSs. The first BS is in an asynchronous timing configuration relative to the one or more second BSs. The computer-executable code also includes code for determining a measurement configuration for measuring one or more signals from the one or more second BSs, based at least in part on the timing difference between the first BS and the one or more second BSs. The computer-executable code further includes code for signaling the measurement configuration to a user equipment (UE) served by the first BS.

[0016] Some aspects provide a method for wireless communication that can be performed by a first BS. The method generally includes receiving a synchronization request from a second BS via a network interface between the first and second BSs, the synchronization request including a first timestamp. The first BS is in an asynchronous timing configuration relative to the second BS. The method also includes sending a synchronization response to the second BS, the synchronization response including at least a second timestamp.

[0017] Some aspects provide an apparatus for wireless communication. The apparatus generally includes at least one processor, a memory coupled to the at least one processor, a receiver, and a transmitter. The receiver is configured to receive a synchronization request from the BS via a network interface between the apparatus and the BS, the synchronization request including a first timestamp. The apparatus is in an asynchronous timing configuration relative to the BS. The transmitter is configured to transmit a synchronization response to the BS, the synchronization response including at least a second timestamp.

[0018] Some aspects provide an apparatus for wireless communication. The apparatus generally includes means for receiving a synchronization request from a BS via a network interface between the apparatus and the BS, the synchronization request including a first timestamp. The apparatus is configured to be asynchronously timed relative to the BS. The apparatus also includes means for sending a synchronization response to the BS, the synchronization response including at least a second timestamp.

[0019] Some aspects provide a computer-readable medium having stored thereon computer-executable code for wireless communication by a first BS. The computer-executable code generally includes code for receiving a synchronization request from a second BS via a network interface between the first and second BSs, the synchronization request including a first timestamp. The first BS is configured to be asynchronously timed relative to the second BS. The computer-executable code also includes code for sending a synchronization response to the second BS, the synchronization response including at least a second timestamp.

[0020] Some aspects provide a method for wireless communication that can be performed by a UE. The method generally includes receiving a measurement configuration from a first BS serving the UE for measuring one or more signals from one or more second BSs. The first BS is in an asynchronous timing configuration relative to the one or more second BSs. The measurement configuration is based on a timing difference between the first BS and the one or more second BSs. The method also includes performing a measurement procedure for the one or more signals according to the measurement configuration.

[0021] Some aspects provide an apparatus for wireless communication. The apparatus generally includes at least one processor, a memory coupled to the at least one processor, and a receiver. The receiver is configured to receive from a first BS serving a UE a measurement configuration for measuring one or more signals from one or more second BSs. The first BS is in an asynchronous timing configuration relative to the one or more second BSs. The measurement configuration is based on a timing difference between the first BS and the one or more second BSs. The at least one processor is configured to perform a measurement procedure for the one or more signals according to the measurement configuration.

[0022] Some aspects provide an apparatus for wireless communication. The apparatus generally includes means for receiving from a first BS serving a UE a measurement configuration for measuring one or more signals from one or more second BSs. The first BS is in an asynchronous timing configuration relative to the one or more second BSs. The measurement configuration is based on a timing difference between the first BS and the one or more second BSs. The apparatus also includes means for performing a measurement procedure for the one or more signals according to the measurement configuration.

[0023] Some aspects provide a computer-readable medium having stored thereon computer-executable code for wireless communication by a UE. The computer-executable code generally includes code for receiving from a first BS serving the UE a measurement configuration for measuring one or more signals from one or more second BSs. The first BS is in an asynchronous timing configuration relative to the one or more second BSs. The measurement configuration is based on a timing difference between the first BS and the one or more second BSs. The computer-executable code also includes code for performing a measurement procedure for the one or more signals according to the measurement configuration.

[0024] To achieve the foregoing and related objectives, these one or more aspects include the features fully described below and specifically pointed out in the claims. Certain illustrative features of these one or more aspects are set forth in detail in the following description and drawings. However, these features merely indicate a few of the various ways in which the principles of these aspects may be employed. Brief description of the attached diagram

[0026] To gain a more detailed understanding of the manner in which the features described above are presented in this disclosure, reference can be made to various aspects of the above brief overview, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as other equivalent aspects are permissible in this description.

[0027] Figure 1 It is a block diagram that conceptually illustrates certain aspects of an example telecommunications system according to this disclosure.

[0028] Figure 2 It is a block diagram that conceptually illustrates the design of an example base station (BS) and user equipment (UE) according to certain aspects of this disclosure.

[0029] Figure 3 Examples of frame formats for new radio (NR) systems according to certain aspects of this disclosure are explained.

[0030] Figure 4 This is an example system architecture for dual connectivity between two radio access technologies (RATs) according to certain aspects of this disclosure.

[0031] Figure 5 This is an example of the transmission of a synchronization signal block (SSB) in a synchronization network according to certain aspects of this disclosure.

[0032] Figure 6 This is an example of SSB transmission in an asynchronous network according to certain aspects of this disclosure.

[0033] Figure 7 An example of bi-connectivity deployment in an asynchronous network scenario is described, based on certain aspects of this disclosure.

[0034] Figure 8 An example call stream for achieving multi-cell synchronization according to certain aspects of this disclosure is explained.

[0035] Figure 9 This is a flowchart illustrating example operations for wireless communication by a serving BS according to certain aspects of this disclosure.

[0036] Figure 10 This is a flowchart illustrating an example operation for wireless communication by a neighboring BS according to certain aspects of this disclosure.

[0037] Figure 11 This is a flowchart illustrating example operations for wireless communication performed by a UE according to certain aspects of this disclosure.

[0038] Figure 12The description of various aspects of this disclosure includes communication devices that may include various components configured to perform operations for the various techniques disclosed herein.

[0039] Figure 13 The description of various aspects of this disclosure includes another communication device that may include various components configured to perform operations for the various techniques disclosed herein.

[0040] Figure 14 The description of various aspects of this disclosure includes another communication device that may include various components configured to perform operations for the various techniques disclosed herein.

[0041] To facilitate understanding, the same reference numerals are used wherever possible to designate common elements shared by all figures. Elements disclosed in one aspect are conceived to be usefully applied in other aspects without specific citation.

[0042] Detailed description

[0043] This disclosure provides apparatus, methods, processing systems, and computer-readable media for achieving multi-cell synchronization for cells in dual connectivity (DC) and / or carrier aggregation (CA) configurations to facilitate UE measurement of signals from neighboring cells.

[0044] Some communication systems can support the deployment of multiple wireless networks within a geographical area. Each wireless network may support a specific radio access technology (RAT) (e.g., LTE, NR, etc.), a specific duplex mode (Time Division Duplex (TDD), Frequency Division Duplex (FDD)), operate on one or more frequencies, support specific parameter designs (e.g., subcarrier spacing, etc.), and so on. In some cases, one or more wireless networks may be in a DC configuration and / or CA configuration. For example, in a DC scenario, a UE may connect to two different radio access network (RAN) nodes (generally referred to herein as BS) (e.g., evolved B node, gNB, enhanced evolved B node, or a combination thereof) and receive services from them. In a CA scenario, one or more component carriers may be combined into a single channel to increase network capacity.

[0045] In some scenarios, when operating in a communication system supporting DC and / or CA, a UE can switch from switching traffic via a first wireless network (e.g., a first RAT) to switching traffic via a second wireless network (e.g., a second RAT). For example, for dual connectivity between E-UTRAN (also known as LTE) and 5G NR, if a large amount of data is transmitted (e.g., above a threshold), the LTE eNB (anchor or serving BS) can trigger the UE to open an NR link with the NR gNB (neighbor BS) and redirect traffic (from the UE) to that NR link. The process of enabling the NR link may involve the UE acquiring the timing of the NR gNB, for example, by detecting a synchronization signal block (SSB) transmitted by the NR gNB. Dual connectivity between E-UTRAN and 5G NR may be referred to as EN-DC.

[0046] To facilitate UE measurement of SSB in EN-DC scenarios, the LTE eNB can configure (or set) the measurement gap based on the assumption that the LTE eNB and the NR gNB (to be measured) are fully synchronized (e.g., there is a synchronized timing configuration between the LTE eNB and the NR gNB). However, in some scenarios, the LTE eNB and NR gNB may not be fully synchronized. As a reference example, an FDD LTE eNB may not be synchronized with other FDD LTE eNBs. As a reference example, an FDD NR gNB may not be synchronized with other FDD NR gNBs. As another reference example, a TDD LTE eNB may not be synchronized with a TDD NR gNB.

[0047] Partly due to asynchronous timing configurations between RAN nodes of different RATs, the UE may be unable to detect neighboring BSs (e.g., NR gNBs) within measurement gaps configured by the serving (or anchor) BS (e.g., LTE eNB). This, in turn, can increase UE downtime and power consumption, thus significantly impacting network performance.

[0048] To address this issue, various approaches have provided techniques to facilitate the measurement of synchronization signals (SS) (e.g., SSBs) transmitted by neighboring BSs. In one particular aspect, the anchor BS can determine the timing difference between itself and its neighboring BS. The anchor BS can then determine, at least in part, a measurement configuration for a UE (served by the anchor BS) to measure signals(s) from the neighboring BS, based on this timing difference. The anchor BS can then signal this measurement configuration to the UE. This reduces the measurement time window for the neighboring cell, allowing the UE to conserve power. Furthermore, reducing the measurement time window enables the UE to conserve power by increasing the throughput of the serving cell due to shorter downtime.

[0049] The following description provides examples facilitating neighbor cell measurements in DC and / or CA scenarios in communication systems, and is not intended to limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the scope of this disclosure. Various procedures or components may be appropriately omitted, substituted, or added to various examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Moreover, features described with reference to some examples may be combined in others. For example, any number of aspects set forth herein may be used to implement an apparatus or practice. Furthermore, the scope of this disclosure is intended to cover such apparatuses or methods practiced using additional structures, functionalities, or structures and functionalities that complement or supplement the various aspects of this disclosure set forth herein. It should be understood that any aspect of this disclosure disclosed herein may be implemented by one or more elements of the claims. The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as superior to or overriding other aspects.

[0050] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network can support a specific Radio Access Technology (RAT) and can operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, frequency modulation, subband, etc. Each frequency can support a single RAT in a given geographical area to avoid interference between wireless networks using different RATs. In some cases, 5G NR RAT networks can be deployed.

[0051] Figure 1 An example wireless communication network 100 in which various aspects of this disclosure can be implemented is described. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network).

[0052] like Figure 1 As explained herein, the wireless communication network 100 may include several base stations (BSs) 110a-z (each individually referred to herein as BS 110 or collectively as BS 110) and other network entities. BS 110 may provide communication coverage for a specific geographic area (sometimes referred to as a “cell”), which may be stationary or mobile depending on the location of the mobile BS 110. In some examples, BS 110 may interconnect with each other and / or interconnect to one or more other BSs or network nodes (not shown) in the wireless communication network 100 using any suitable transport network through various types of backhaul interfaces (e.g., direct physical connection, wireless connection, virtual network, etc.). Figure 1In the example shown, BS 110a, 110b, and 110c can be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x can be a pico BS for pico cell 102x. BS 110y and 110z can be femto BSs for femto cells 102y and 102z, respectively. A BS can support one or more cells. BS 110 communicates with user equipment (UE) 120a-y (each individually referred to herein as UE 120 or collectively as UE 120) in the wireless communication network 100. UE 120 (e.g., 120x, 120y, etc.) can be distributed throughout the wireless communication network 100, and each UE 120 can be stationary or mobile.

[0053] As shown in the figure, BS 110a includes a measurement component 160 configured to implement one or more techniques described herein. Using the measurement component 160, BS 110a can determine a timing difference between BS 110a and at least one other BS (e.g., BS 110b). For example, BS 110a may be in an asynchronous timing configuration relative to the other BS. BS 110a can determine a measurement configuration for measuring one or more signals from the other BS, at least in part, based on the timing difference between BS 110a and the other BS via the measurement component 160. BS 110a can signal this measurement configuration to a UE (e.g., UE 120a) served by BS 110a.

[0054] In some aspects, assuming BS 110a is a neighboring BS, BS 110a can use measurement component 160 to receive a synchronization request from another BS (e.g., BS 110b) via the network interface between BS 110a and that BS 110a. The synchronization request includes a first timestamp. BS 110a may be in an asynchronous timing configuration relative to the other BS. BS 110a may send a synchronization response to the other BS via measurement component 160, the synchronization response including at least a second timestamp.

[0055] The wireless communication network 100 may also include a relay station (e.g., relay station 110r) (also referred to as a relay, etc.) that receives data and / or other information transmissions from an upstream station (e.g., BS 110a or UE 120r) and sends data and / or other information transmissions to a downstream station (e.g., UE 120 or BS 110), or relays transmissions between the UEs 120 to facilitate communication between the devices.

[0056] Network controller 130 can be coupled to a group of BS 110 and provide coordination and control over these BS 110. Network controller 130 can communicate with BS 110 via backhaul. BS 110 can also communicate with each other via wireless or wired backhaul (e.g., directly or indirectly).

[0057] Figure 2 The BS 110a and UE 120a, which can be used to implement various aspects of this disclosure, are explained (e.g., in...). Figure 1 Example components in wireless communication network 100.

[0058] At BS 110a, the transmit processor 220 can receive data from data source 212 and control information from controller / processor 240. This control information can be used for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Group Shared PDCCH (GC PDCCH), etc. This data can be used for the Physical Downlink Shared Channel (PDSCH), etc. The processor 220 can process (e.g., encode and map symbol) the data and control information to obtain data symbols and control symbols respectively. The transmit processor 220 can also generate reference symbols (such as those used for the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Cell-Specific Reference Signal (CRS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols where applicable, and can provide the output symbol stream to modulators (MODs) 232a-232t. Each modulator 232 can process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signal from modulators 232a-232t can be transmitted via antennas 234a-234t respectively.

[0059] At UE 120a, antennas 252a-252r can receive downlink signals from BS 110a and can provide the received signals to demodulators (DEMODs) in transceivers 254a-254r respectively. Each demodulator 254 can condition (e.g., filter, amplify, down-convert, and digitize) its respective received signal to obtain an input sample. Each demodulator can further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 can obtain the received symbols from all demodulators 254a-254r, perform MIMO detection on these received symbols where applicable, and provide detected symbols. Receiver processor 258 can process (e.g., demodulate, deinterleave, and decode) these detected symbols, provide the decoded data to UE 120a to data sink 260, and provide the decoded control information to controller / processor 280.

[0060] On the uplink, at UE 120a, transmit processor 264 can receive and process data from data source 262 (e.g., for the Physical Uplink Shared Channel (PUSCH)) and control information from controller / processor 280 (e.g., for the Physical Uplink Control Channel (PUCCH)). Transmit processor 264 can also generate reference symbols for reference signals (e.g., probe reference signals (SRS)). Symbols from transmit processor 264 can be pre-encoded by TX MIMO processor 266 where applicable, further processed by demodulators in transceivers 254a-254r (e.g., for SC-FDM, etc.), and transmitted to BS 110a. At BS 110a, uplink signals from UE 120a can be received by antenna 234, processed by modulator 232, detected by MIMO detector 236 where applicable, and further processed by receive processor 238 to obtain decoded data and control information transmitted by UE 120a. The receiver processor 238 can provide decoded data to the data trap 239 and decoded control information to the controller / processor 240.

[0061] Memory 242 and 282 may store data and program code for use by BS 110a and UE 120a, respectively. Scheduler 244 may schedule UE for data transmission on the downlink and / or uplink. Controller / processor 240 and / or other processors and modules at BS 110a may execute or direct the execution of processes of the techniques described herein. For example, as Figure 2 As shown, the controller / processor 240 of BS 110a includes a measurement component 160, which can be configured to perform... Figure 9 The operation explained in the text is 900. Figure 10The operation 1000 described herein and / or one or more other techniques described herein. Similarly, the controller / processor 280 and / or other processors and modules at UE 120a may perform or direct the execution of processes using the techniques described herein. For example, as Figure 2 As shown, the controller / processor 280 of UE 120a includes a measurement component 170, which can be configured to perform... Figure 11 The operation 1100 described herein and / or one or more other techniques described herein. Although shown at the controller / processor, other components of UE 120a and BS 110a may also be used to perform the operations described herein.

[0062] Figure 3 This is a diagram illustrating an example of frame format 300 for NR. The transmission timeline for each of the downlink and uplink can be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes with indices 0 to 9, each subframe being 1 ms long. Each subframe may include a variable number of time slots, depending on the subcarrier spacing. Each time slot may include a variable number of symbol periods (e.g., 7 or 14 symbols), depending on the subcarrier spacing. An index may be assigned to the symbol periods in each time slot. A mini-time slot (which may be referred to as a sub-time slot structure) refers to a transmission time interval with a duration smaller than a time slot (e.g., 2, 3, or 4 symbols).

[0063] Each symbol in a time slot can indicate the link direction used for data transmission (e.g., DL, UL, or flexible), and the link direction used for each subframe can be dynamically switched. The link direction can be based on the time slot format. Each time slot can include DL / UL data and DL / UL control information.

[0064] In NR, a synchronization signal (SSB) block is transmitted. The SSB includes the PSS, SSS, and two-symbol PBCH. The SSB can be located at a fixed time slot position (such as...). Figure 3The PSS and SSS are transmitted in symbols 0-3 shown in the diagram. The PSS and SSS can be used by the UE for cell search and acquisition. The PSS provides half-frame timing, and the SS provides CP length and frame timing. The PSS and SSS provide cell identity. The PBCH carries basic system information such as downlink system bandwidth, timing information within the radio frame, SS burst set periodicity, and system frame number. SSBs can be organized into SS bursts to support beam sweeping. Further system information (such as Residual Minimum System Information (RMSI), System Information Block (SIB), and Other System Information (OSI)) can be transmitted on the PDSCH in certain subframes. SSBs can be transmitted up to 64 times, for example, up to 64 different beam directions for mmW. Up to 64 transmissions of an SSB are called an SS burst set. SSBs in an SS burst set are transmitted in the same frequency region, while SSBs in different SS burst sets can be transmitted at different frequency locations.

[0065] Figure 4 This is a block diagram illustrating an example system architecture 400 for dual connectivity (DC) (EN-DC) between E-UTRAN and 5G NR according to certain aspects of this disclosure. As previously stated, in the case of 5G deployment, UE 410 (e.g., Figure 1 UE120a) may have dual connectivity functionality, which allows UE 410 to simultaneously communicate with a first BS 420 utilizing LTE RAT (e.g., Figure 1 BS 110a (e.g., communication with evolved B-nodes (eNBs)) and a second BS 430 utilizing 5G NR RAT (e.g., Figure 1 The first BS 420 and the second BS 430 communicate with each other (e.g., with a next-generation BS (gNB)). Although this example system architecture shows the first BS 420 and the second BS 430 as separate base stations, this disclosure is not limited thereto, and the first BS 420 and the second BS 430 can be a single base station (e.g., Figure 1 Separate physical entities (e.g., transceivers) or separate logical entities (e.g., different software modules executing on a processing system having a transceiver) within BS 110a.

[0066] UE 410 is configured to participate in dual-connectivity communication with a first BS 420 via interface 402 (e.g., a radio interface such as the Uu interface) and with a second BS 430 (e.g., a radio interface such as the Uu interface) via interface 404. Here, the first BS 420 and the second BS 430 may be connected to each other via interface 406 (e.g., the X2 interface or typically the Xn interface), as shown. The first BS 420 may be connected to the evolved packet core (EPC) 440 via interface 408 (e.g., the S1 interface), where interface 408 connects to the Mobility Management Entity (MME) (control plane) and the System Architecture Evolution (SAE) Gateway (S-GW) (user plane). In some aspects of this disclosure, the second BS 430 may optionally be connected to the EPC 440 on the user plane via interface 409 (e.g., the S1-U interface).

[0067] In some systems, such as version 15 of the 3GPP radio standard for NR (New Radio or 5G access technology), radio resource management (RRM) measurements are performed. RRM measurements may include, for example, Channel Quality Indicator (CQI), Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and / or Received Signal Strength Indicator (RSSI) measurements. RRM measurements may be used for mobility decisions, link adaptation, scheduling, and / or other purposes.

[0068] In some examples, a common reference signal (CRS) is used for RRM measurements. In NR, synchronization signals (NR-SS) (such as SSB) and / or channel state information reference signals (CSI-RS) can be used to perform RRM measurements. CSI-RS-based RRM can provide an improved beamforming solution. In some examples, only one type of RS is configured for a periodic and / or event-triggered measurement report.

[0069] For asynchronous network deployments, SSB can be used for RRM measurements (e.g., referred to as SSB-based RRM measurements). The SSB can be a "constant" reference signal. The SSB can include a 1-symbol PSS, a 1-symbol SSS, and a 2-symbol PBCH that are time-division multiplexed (performed TDM) within consecutive symbols. In some examples, the transmission of the SSB within an SS burst can be restricted to a window.

[0070] A cell can be associated with an SSB Measurement Timing Configuration (SMTC) based on its configuration for SSB transmission. The SMTC can define: SMTC window duration (e.g., {1,2,3,4,5} ms); SMTC window timing offset (e.g., {0,1,…,SMTC periodicity-1} ms); and SMTC periodicity (e.g., {5,10,20,40,80,160} ms). The SMTC can be configured by the network for SSB-based RRM measurements. For example, the SMTC can be configured with measurement objects.

[0071] In some systems, such as version-15NR, the network is synchronous. In asynchronous networks, the timing offset between cells is smaller. Therefore, as... Figure 5 As shown, in an asynchronous network, target cell SSBs 506, 506 fall within the same SMTC windows 502, 504 as serving cell SSBs 510, 512. However, in some systems, such as version-16NR, the network may be asynchronous. In this case, the target cell(s) to be measured in the target frequency may be asynchronous with the UE's serving cell. Therefore, the SSBs of the serving cell and the target may not be aligned. Figure 6 As shown, in an asynchronous network, the SSBs (610, 612) from the serving cell and the SSBs 606, 608 from the target cell have a time offset (which may be large), and the SSBs 606, 608 of the target cell may be outside the SMTC window 602, 604. In this case, the UE may have to perform blind detection of the target cell's SSB, which can increase the UE's downtime and / or increase the UE's power consumption.

[0072] As mentioned above, in scenarios where multiple cells are in DC and / or CA configurations, asynchronous network deployment can lead to a significant amount of data exchange interruption for the UE and / or a substantial increase in UE power consumption. For example, Figure 4 The EN-DC deployment depicted herein is considered a reference example of a DC scenario. In this scenario, if there is a large amount of data to be transmitted (e.g., from UE 410), a first BS 420 (which is serving UE 410) can trigger UE 410 to open an NR link via a second BS 430 (which is a neighboring BS) and guide traffic through that NR link. The process of enabling the NR link may involve UE 410 obtaining the timing of the second BS 430, for example, by detecting the SSB transmitted by the second BS 430.

[0073] To facilitate UE measurement of the SSB, the first BS 420 may configure (or set) the measurement gap based on the assumption (e.g., synchronized timing configuration) that the first BS 420 and the second BS 430 (to be measured) are fully synchronized. However, in some scenarios, the first BS 420 and the second BS 430 may not be fully synchronized. As a reference example, an FDD LTE BS (e.g., the first BS) may not be synchronized with other FDD LTE BSs (e.g., the second BS). As another reference example, an FDD NR BS (e.g., the first BS) may not be synchronized with other FDD NR BSs (e.g., the second BS). As yet another reference example, a TDD LTE BS (e.g., the first BS) may not be synchronized with a TDD NR BS (e.g., the second BS).

[0074] For example, in Figure 7 In the EN-DC scenario depicted, each of the FDD LTE BSs 1-3 is asynchronous relative to each other and relative to each of the TDD NR BSs 1-K. On the other hand, the TDD NR BSs 1-K are deployed synchronously (e.g., each of the TDD NR BSs 1-K is synchronous relative to each other). Partly due to the asynchronous timing configuration between RAN nodes of different RATs, the UE may be unable to detect neighboring BSs (e.g., NR gNBs) within the measurement gaps configured by the serving BS (e.g., LTE eNB). This, in turn, can increase UE downtime and power consumption, thus significantly impacting network performance.

[0075] Accordingly, it may be desirable to provide technologies that enable UEs to perform measurement procedures and asynchronous network deployments in DC and / or CA scenarios.

[0076] Example multi-cell synchronization for DC and CA

[0077] The aspects presented in this paper provide techniques that facilitate the measurement of synchronization signals (e.g., SS, SSB, etc.) transmitted by neighboring BSs (e.g., gNB, eNB, eLTE eNB, etc.). The techniques described in this paper are applicable to a variety of multi-cell deployment scenarios.

[0078] In an example scenario (referred to herein as Scenario 1) (e.g., EN-DC), an FDD LTE BS (anchor) (e.g., BS 110a) may be in the DC with a TDD NR BS (e.g., BS 110b). One issue with Scenario 1 is that the FDD LTE BS(s) may not be synchronized with other FDD LTE BS(s) and / or with TDD NR BS(s). Therefore, without knowing the timing difference between the LTE anchor and the NR BS(s), the LTE anchor may be configured with insufficient measurement gaps for the UE to measure the SSBs from the NR BS(s) of interest. For example, the LTS SS periodicity can be 5ms, and the NR SSB periodicity can be up to 20ms; generally, operators typically set the LTE measurement gap to 6ms (which is greater than the SS period). However, in some standards (e.g., TS38.133), the measurement gap for NR can be up to 6ms. Therefore, in scenario 1, a 6ms measurement gap may be insufficient for NR SMTC without any timing alignment information about neighboring NR BS.

[0079] To address this issue in Scenario 1, various approaches have been developed to enable each FDD LTE BS to acquire the timing difference with the TDD NR BS and configure a measurement window based on this timing difference. In one approach, the FDD LTE BS may execute a new procedure on the network interface (e.g., interface 406 (such as the Xn interface)) to obtain the timing difference with the TDD NR BS. For example... Figure 8 As shown in example call flow 800, the procedure may involve sending a synchronization message (e.g., a synchronization request 802) from an anchor LTE BS (e.g., BS 110a) to a target NR BS (e.g., BS 110b), the synchronization message including a (first) timestamp. In response, the NRBS may respond with another synchronization message (e.g., a synchronization response 804), the other synchronization message including a (second) timestamp. For example, the synchronization message sent in 802 and / or 804 may be a “sequence + payload (timestamp)”. The anchor LTE BS may (in 806) determine a timing difference based on the (first) timestamp in synchronization request 802 and the (second) timestamp in synchronization response 804. For example, the timing difference may be set as the difference between the (first) timestamp in synchronization request 802 and the (second) timestamp in synchronization response 804.

[0080] Note that in scenario 1 (e.g., having an anchor FDD LTE BS and several TDD NR BSs), the timing difference between a given FDD LTE BS and each TDD NR BS (determined at 806) is the same single value (e.g., since the TDD NR BSs can be fully synchronized). Furthermore, note that while the above technique is described with reference to an FDD LTE BS (as anchor) and a TDD NR BS as neighboring cells, the above technique is also applicable to both TDD LTE BS (as anchor) and TDD NR BS as neighboring cells.

[0081] Other techniques can also be used to obtain the timing difference between the anchor LTE BS and its neighboring NR BSs (at 806). In one example technique, a shared and unique timing reference can be predefined for each BS. This unique timing reference can be based on GPS, IEEE 1588, etc. Another example technique involves the anchor LTE BS listening to the synchronization signals of its neighboring NR BSs. Yet another example technique involves the UE measuring this gap and reporting it to the serving BS.

[0082] In one aspect, once the timing difference is acquired (at 806), the anchor LTE BS can determine the measurement configuration based on the timing difference (at 808) and send the measurement configuration to the UE (e.g., UE 120a) (at 810). In one example, the anchor LTE BS can send the measurement configuration (including an indication of the timing difference) to the UE when requesting the UE to perform an SMTC. For example, the new element “Timing Difference” can be included in the Radio Resource Control (RRC) message “MeasObjectNR (Measurement Object NR)”. The element “Timing Difference” can be a timing difference relative to the serving cell and can include at least one of the following: System Frame Number (SFN) offset, slot-level offset, or symbol-level offset. In a reference example, the timing difference can indicate the following:

[0083]

[0084] The UE can perform a measurement procedure (in 814) based on the measurement configuration to measure one or more signals received from the anchor LTE BS 812. Note that in some aspects, the time slots and symbol offsets may have different time lengths if the subcarrier spacing is different. In some cases, for example, the time slots and / or symbol offsets may be based on the subcarrier spacing of the target cell. In some cases, the time slots and / or symbol offsets may be based on the subcarrier spacing of the serving cell. In some cases, the time slots and / or symbol offsets may be based on the higher subcarrier spacing between the target cell and the serving cell.

[0085] In another example scenario (referred to as Scenario 2 in this document), an FDD NR BS (anchor) (e.g., BS 110a) may be in the DC with another FDD NR BS (e.g., BS 110b). Similar to Scenario 1, one issue with Scenario 2 is that the NR anchor BS may not be synchronized with its NR neighbor BS, and therefore, the NR anchor BS may be unaware of the timing difference with its NR neighbor BS. This could result in the NR anchor BS being configured with a 6ms measurement gap, which may be insufficient without timing alignment information.

[0086] To address the issue in Scenario 2, various aspects could enable each NR BS to acquire the timing differences of neighboring cells (e.g., at 806) and configure a measurement window based on this set of timing differences (e.g., at 808). Compared to Scenario 1, because neighboring cells are not time-aligned, the timing differences in Scenario 2 (at 806) could include a list of timing difference values. Furthermore, compared to Scenario 1, the network interface could be between (gNBs) rather than between eNBs and gNBs. In one aspect, the NR anchor BS could optimize the measurement configuration by determining the measurement configuration (at 808) as the sum of measurement windows for a subset of NR neighbor BSs. For example, the NR anchor BS could determine the subset of NR neighbor BSs based on at least one of UE location or BS signal strength.

[0087] In another example scenario (referred to herein as Scenario 3), a TDD NR BS (anchor) (e.g., BS 110a) may be in the DC with an FDD-enhanced LTE BS (e.g., BS 110b). One issue with Scenario 3 is that while the NR anchor BS can be synchronized with other TDD NR BSs, it may be unaware of the timing difference with asynchronous LTE neighboring BSs. However, in this scenario, a 6ms measurement gap may be sufficient for the LTE BS. In some respects, the NR anchor BS can further reduce the measurement gap by maintaining a list of timing differences with neighboring cells and configuring the largest timing difference as the measurement window (e.g., at 808). As an NR anchor BS in a synchronized network, this single difference table can be shared with neighboring NR anchor BSs.

[0088] Additionally, for scenario 3, the NR anchor BS can optimize the measurement configuration by determining the measurement configuration (at 808) as the sum of the measurement windows of the selected neighboring BSs. BS selection criteria may be based on, for example, at least one of UE location or BS signal strength.

[0089] Figure 9This is a flowchart illustrating an example operation 900 for wireless communication according to certain aspects of this disclosure. Operation 900 may be performed, for example, by an anchor (or serving) BS (such as BS 110a in wireless communication network 100, for example). Operation 900 may be implemented in one or more processors (e.g., Figure 2 The software components executed and running on the controller / processor 240. Furthermore, the signal transmission and reception performed by the BS in operation 900 may be, for example, by one or more antennas (e.g., Figure 2 The antenna 234) is used for implementation. In some aspects, signal transmission and / or reception by the BS can be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 240).

[0090] Operation 900 can begin at 905, where the first (anchor) BS determines a timing difference between itself and one or more second (neighbor) BSs (e.g., BS 110b). The first BS is in an asynchronous timing configuration relative to the one or more second BSs. In some aspects, the first BS may be associated with a first radio access technology (RAT) and a first duplex mode, and the one or more second BSs may be associated with a second RAT and a second duplex mode.

[0091] In some aspects, the timing difference (at 905) may include at least one of system frame number offset, time slot offset, or symbol offset. In some aspects, at least one of the time slot offset or symbol offset may be based on (i) the subcarrier spacing of one or more second BSs, or (ii) the subcarrier spacing of the first BS, or (iii) the highest subcarrier spacing between the first BS and the one or more second BSs.

[0092] At 910, the first BS determines a measurement configuration for measuring one or more signals from the one or more second BSs, at least in part, based on the timing difference between the first BS and the one or more second BSs. At 915, the anchor BS signals the measurement configuration to the UE (e.g., UE 120a).

[0093] In one aspect, the timing difference (at 905) can be a single timing difference value. In this aspect, the first BS can determine the timing difference by: (i) sending a synchronization request (e.g., synchronization request 802) to the second BS via a network interface between the first BS and one of the one or more second BSs, the synchronization request including a first timestamp; (ii) receiving a synchronization response (e.g., synchronization response 804) from the second BS via the network interface, the synchronization response including at least a second timestamp; and (iii) setting the single timing difference value as the difference between the first timestamp and the second timestamp. In this aspect, determining the measurement configuration (at 910) may include determining a measurement window for measuring the one or more signals from the one or more second BSs based on the single timing difference value. Furthermore, in this aspect, the first RAT can be LTE and the first duplex mode can be FDD or TDD, while the second RAT can be NR and the second duplex mode can be TDD.

[0094] In one aspect, the timing difference (at 905) may include multiple timing difference values. In this case, the first BS may determine the timing difference by: (i) sending a synchronization request (e.g., synchronization request 802) to the second BS via a network interface between the first BS and each of the one or more second BSs, the synchronization request including a first timestamp; (ii) receiving a synchronization response (e.g., synchronization response 804) from each of the one or more second BSs via the network interface, the synchronization response including at least a second timestamp; and (iii) setting the timing difference value for each second timestamp received from the second BS as the difference between the first timestamp and the second timestamp.

[0095] In this respect, the first BS can determine the measurement configuration (at 910) by determining a measurement window for measuring the one or more signals from the one or more second BSs based on the plurality of timing differences. For example, the measurement window may be based on the sum of the plurality of timing differences. In some cases, the first BS may select one or more second BSs from a plurality of second BSs adjacent to the first BS. The selected one or more second BSs may be selected based on at least one of the UE's location or the signal strength of the second BS.

[0096] In some cases, the first RAT can be NR and the first duplex mode can be FDD, while the second RAT can be NR and the second duplex mode can be FDD. In another example, the first RAT can be NR and the first duplex mode can be TDD, while the second RAT can be LTE and the second duplex mode can be FDD.

[0097] Figure 10This is a flowchart illustrating an example operation 1000 for wireless communication according to certain aspects of this disclosure. Operation 1000 may be performed, for example, by a neighboring BS (such as BS 110b in wireless communication network 100). Operation 1000 may be implemented in one or more processors (e.g., Figure 2 The software components executed and running on the controller / processor 240. Furthermore, the signal transmission and reception performed by the BS in operation 1000 can be, for example, by one or more antennas (e.g., Figure 2 The antenna 234) is used for implementation. In some aspects, signal transmission and / or reception by the BS can be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 240).

[0098] Operation 1000 may begin at 1005, wherein a first (adjacent) BS (e.g., BS 110b) receives a synchronization request (e.g., synchronization request 802) from the second BS via the network interface between the first BS and the second (anchor) BS (e.g., BS 110a), the synchronization request including a first timestamp. The first BS may be in an asynchronous timing configuration relative to the second BS. At 1010, the first BS sends a synchronization response to the second BS, the synchronization response including at least a second timestamp.

[0099] In some aspects, a first (adjacent) BS may be associated with a first RAT and a first duplex mode, and a second (anchor) BS may be associated with a second RAT and a second duplex mode. In one scenario, the first RAT may be NR and the first duplex mode may be TDD, while the second RAT may be LTE and the second duplex mode may be FDD. In another scenario, the first RAT may be NR and the first duplex mode may be TDD, while the second RAT may be LTE and the second duplex mode may be TDD. In yet another scenario, the first RAT may be NR and the first duplex mode may be FDD, while the second RAT may be NR and the second duplex mode may be FDD. In yet another scenario, the first RAT may be LTE and the first duplex mode may be FDD, while the second RAT may be NR and the second duplex mode may be TDD.

[0100] Figure 11 This is a flowchart illustrating an example operation 1100 for wireless communication according to certain aspects of this disclosure. Operation 1100 can be performed, for example, by a UE (e.g., UE 120a such as in wireless communication network 100). Operation 1100 can be an operation performed by the UE that is complementary to operation 900 performed by a BS. Operation 1100 can be implemented in one or more processors (e.g., Figure 2The software components executed and running on the controller / processor 280. Furthermore, in operation 1100, the transmission and reception of signals by the UE can be, for example, by one or more antennas (e.g., Figure 2 The antenna 252 is used for this purpose. In some respects, signal transmission and / or reception by the UE can be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 280).

[0101] Operation 1100 may begin at 1105, wherein the UE receives a measurement configuration from an anchor BS (e.g., BS 110a) serving the UE for measuring one or more signals from one or more second BSs (e.g., BS 110b). The first BS may be in an asynchronous timing configuration relative to the one or more second BSs, and the measurement configuration may be based on the timing difference between the anchor BS and the one or more adjacent BSs. At 1110, the UE may perform a measurement procedure for the one or more signals according to the measurement configuration. The measurement configuration (at 1105) may include an indication of a measurement window for measuring the one or more signals from the one or more second BSs.

[0102] In some aspects, a first (anchor) BS may be associated with a first RAT and a first duplex mode, and a second (adjacent) BS may be associated with a second RAT and a second duplex mode. In one scenario, the first RAT may be LTE and the first duplex mode may be FDD, while the second RAT may be NR and the second duplex mode may be TDD. In another scenario, the first RAT may be LTE and the first duplex mode may be TDD, while the second RAT may be NR and the second duplex mode may be TDD. In yet another scenario, the first RAT may be NR and the first duplex mode may be FDD, while the second RAT may be NR and the second duplex mode may be FDD. In yet another scenario, the first RAT may be NR and the first duplex mode may be TDD, while the second RAT may be LTE and the second duplex mode may be FDD. Measurement configuration may be based on at least one of the first RAT, the first duplex mode, the second RAT, or the second duplex mode.

[0103] In some aspects, the timing difference may include at least one of system frame number offset, time slot offset, or symbol offset. In some aspects, at least one of the time slot offset or symbol offset may be based on (i) the subcarrier spacing of one or more second BSs, or (ii) the subcarrier spacing of the first BS, or (iii) the highest subcarrier spacing between the first BS and the one or more second BSs.

[0104] Figure 12 The description includes operations that may be configured to perform the techniques disclosed herein (such as...). Figure 9The communication device 1200 comprises various components (e.g., corresponding to device plus functional components) of the operation described herein. The communication device 1200 includes a processing system 1202 coupled to a transceiver 1208. The transceiver 1208 is configured to transmit and receive signals (such as the various signals described herein) for the communication device 1200 via an antenna 1210. The processing system 1202 may be configured to perform processing functions for the communication device 1200, including processing signals received and / or to be transmitted by the communication device 1200.

[0105] Processing system 1202 includes processor 1204 coupled to computer-readable medium / memory 1212 via bus 1206. In some aspects, computer-readable medium / memory 1212 is configured to store data that, when executed by processor 1204, causes processor 1204 to perform... Figure 9 The operation 900 described herein or other operations performed using the various techniques discussed herein (e.g., computer-executable code) may be included. In some aspects, the computer-readable medium / memory 1212 stores code 1214 for determining a timing difference between a first (anchor) BS and (adjacent) second BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs; code 1216 for determining a measurement configuration for measuring one or more signals from the one or more second BSs, based at least in part on the timing difference between the first BS and the one or more second BSs; code 1218 for signaling the measurement configuration to user equipment (UE) served by the first BS; and so on. In some aspects, the processor 1204 has a circuitry configured to implement the code stored in the computer-readable medium / memory 1212. Processor 1204 includes circuitry 1220 for determining a timing difference between a first (anchor) BS and (adjacent) second BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs; circuitry 1224 for determining a measurement configuration for measuring one or more signals from the one or more second BSs based at least in part on the timing difference between the first BS and the one or more second BSs; circuitry 1226 for signaling the measurement configuration to user equipment (UE) served by the first BS; and so on.

[0106] Figure 13 The explanation may include operations that can be configured to perform the techniques disclosed herein (such as, Figure 10The communication device 1300 comprises various components (e.g., corresponding to device plus functional components) of the operation described herein. The communication device 1300 includes a processing system 1302 coupled to a transceiver 1308. The transceiver 1308 is configured to transmit and receive signals (such as the various signals described herein) for the communication device 1300 via an antenna 1310. The processing system 1302 may be configured to perform processing functions for the communication device 1300, including processing signals received and / or to be transmitted by the communication device 1300.

[0107] Processing system 1302 includes processor 1304 coupled to computer-readable medium / memory 1312 via bus 1306. In some aspects, computer-readable medium / memory 1312 is configured to store data that, when executed by processor 1304, causes processor 1304 to perform... Figure 10 The operation 1000 described herein or other operations performed using the various techniques discussed herein may be instructions (e.g., computer-executable code). In some aspects, the computer-readable medium / memory 1312 stores code 1314 for receiving a synchronization request from a second BS via a network interface between a first (adjacent) BS and a second (anchor) BS, the synchronization request including a first timestamp, wherein the first BS is in an asynchronous timing configuration relative to the second BS; and code 1316 for sending a synchronization response to the second BS, the synchronization response including at least a second timestamp. In some aspects, the processor 1304 has circuitry configured to implement the code stored in the computer-readable medium / memory 1312. The processor 1304 includes circuitry 1320 for receiving a synchronization request from a second BS via a network interface between the first BS and the second BS, the synchronization request including a first timestamp, wherein the first BS is in an asynchronous timing configuration relative to the second BS; and circuitry 1324 for sending a synchronization response to the second BS, the synchronization response including at least a second timestamp.

[0108] Figure 14 The description includes operations that may be configured to perform the techniques disclosed herein (such as, Figure 11 The communication device 1400 comprises various components (e.g., corresponding to device plus functional components) of the operation described herein. The communication device 1400 includes a processing system 1402 coupled to a transceiver 1408. The transceiver 1408 is configured to transmit and receive signals (such as the various signals described herein) for the communication device 1400 via an antenna 1410. The processing system 1402 may be configured to perform processing functions for the communication device 1400, including processing signals received and / or to be transmitted by the communication device 1400.

[0109] Processing system 1402 includes processor 1404 coupled to computer-readable medium / memory 1412 via bus 1406. In some aspects, computer-readable medium / memory 1412 is configured to store data that, when executed by processor 1404, causes processor 1404 to perform... Figure 11 The operation 1100 described herein or other operations for performing the various techniques discussed herein may be instructions (e.g., computer-executable code). In some aspects, the computer-readable medium / memory 1412 stores code 1414 for receiving from a first base station (BS) serving the UE a measurement configuration for measuring one or more signals from one or more second (adjacent) BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs, and wherein the measurement configuration is based on a timing difference between the first BS and the one or more second BSs; and code 1416 for performing a measurement procedure for the one or more signals according to the measurement configuration. In some aspects, the processor 1404 has a circuit system configured to implement the code stored in the computer-readable medium / memory 1412. The processor 1404 includes circuitry 1420 for receiving from a first base station (BS) serving the UE a measurement configuration for measuring one or more signals from one or more second (adjacent) BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs, and wherein the measurement configuration is based on a timing difference between the first BS and the one or more second BSs; and circuitry 1424 for performing a measurement procedure for the one or more signals according to the measurement configuration.

[0110] The techniques described in this document can be used in various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), LTE-A Advanced (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. CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. TDMA networks can 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), IEEE 802.20, and Flash-OFDMA. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are UMTS versions using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). NR is an emerging wireless communication technology under development.

[0111] The techniques described herein can be used in the wireless networks and radio technologies mentioned above, as well as other wireless networks and radio technologies. For clarity, although aspects may be described herein using terms commonly associated with 3G, 4G, and / or 5G wireless technologies, aspects of this disclosure can be applied to communication systems based on other generations.

[0112] In 3GPP, the term "cell" can refer to the coverage area of ​​a B-node (NB) and / or the NB subsystem serving that 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 cell (DU), carrier, or transmit / receive point (TRP) can be used interchangeably. A BS can provide communication coverage for macrocells, picocells, femtocells, and / or other types of cells. A macrocell can cover a relatively large geographic area (e.g., a radius of several kilometers) and allows unrestricted access by UEs with a service subscription. A picocell can cover a relatively small geographic area and allows unrestricted access by UEs with a service subscription. A femtocell can cover a relatively small geographic area (e.g., a residential area) and allows restricted access by UEs associated with that femtocell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a residential area, etc.). A BS used for a macrocell can be referred to as a macro BS. A BS used for picocells can be called a picoBS. A BS used for femtocells can be called a femtoBS or a home BS.

[0113] A UE can also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smartphone, 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 smartwatch, 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.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, GPS device, or any other suitable device configured to communicate via wireless or wired media. 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 another entity. Wireless nodes can provide connectivity to or to a network (e.g., a wide area network such as the Internet) or a cellular network, for example, via wired or wireless communication links. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0114] 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, often referred to as frequency modulation, frequency slots, etc. Each subcarrier can be modulated with data. Generally, modulation symbols are transmitted 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 subcarrier spacing could be 15 kHz, and the minimum resource allocation (called a "resource block" (RB)) could be 12 subcarriers (or 180 kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, the nominal Fast Fourier Transform (FFT) size could be 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, a subband can cover 1.08 MHz (e.g., 6 RBs), and for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, there can be 1, 2, 4, 8, or 16 subbands, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0115] NR can utilize OFDM with CP on both uplink and downlink and includes support for half-duplex operation using TDD. In NR, a subframe is still 1ms, but the basic TTI is called a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16... slots) depending on the subcarrier spacing. NR RB is 12 coherent frequency subcarriers. NR supports 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. Symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming is supported and beam direction can be dynamically configured. MIMO transmission with precoding is also supported. In some examples, MIMO configurations in DL can support up to 8 transmit antennas (with up to 8 streams in multilayer DL transmission) and up to 2 streams per UE. In some examples, multi-layer transport of up to two streams per UE can be supported. Up to eight serving cells can be used to support aggregation of multiple cells.

[0116] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entity utilizes the 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 can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize the resources scheduled by that 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 the mesh network example, UEs may communicate directly with each other in addition to communicating with a scheduling entity.

[0117] In some examples, two or more subordinate entities (e.g., UEs) may use sidelink signaling to communicate with each other. Real-world applications of such sidelink communication may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Things (IoE) communication, IoT communication, mission-critical mesh networks, and / or various other suitable applications. Generally, sidelink signaling can refer to a signal that is relayed from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without requiring the relaying of that communication by 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, sidelink signaling may be transmitted using licensed spectrum (unlike wireless LANs, which typically use unlicensed spectrum).

[0118] The methods disclosed herein include one or more steps or actions for implementing the method. These method steps and / or actions may be interchanged 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 may be modified without departing from the scope of the claims.

[0119] As used herein, the phrase “at least one of” a list of items refers to any combination of those items, including a single member. 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, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0120] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" can include calculation, computation, processing, derivation, research, searching (e.g., looking in a table, database, or other data structure), ascertaining, and the like. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and the like. Moreover, "determine" can include parsing, selecting, choosing, building, and the like.

[0121] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will readily be understood by those skilled in the art, and the universal principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be granted the full scope consistent with the language of the claims, wherein references to the singular form of an element are not intended to mean “one and only one” (unless specifically stated otherwise) but “one or more.” Unless specifically stated otherwise, the term “some / a” refers to one or more. All structural and functional equivalents of the aspects described throughout this disclosure that are now or hereafter known to a person skilled in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be donated to the public, whether or not such disclosure is expressly stated in the claims. No element of a claim should be interpreted in accordance with the provisions of 35 U.S.SC §112(f) unless the element is expressly stated using the phrase “means for…” or, in the case of a method claim, the element is stated using the phrase “steps for…”.

[0122] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means 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 the operations illustrated in the figures are present, these operations may have corresponding paired means with similar numbers plus functional components.

[0123] The various illustrative logic blocks, modules, and circuits described in this disclosure can be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), 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. The general-purpose processor may be a microprocessor, but in alternatives, 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, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0124] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system can 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 interconnect buses and bridges. The bus can link together various circuits, including a processor, machine-readable media, and a bus interface. The bus interface can be used to connect network adapters, etc., to the processing system via the bus. The network adapter can be used to implement signal processing functions at the PHY layer. In user terminal 120 (see...) Figure 1 In such cases, the user interface (e.g., keypad, display, mouse, joystick, etc.) can also be connected to the bus. The bus can also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and similar circuits, which are well known in the art and will not be described further. The processor can be implemented using one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuit systems capable of executing software. Depending on the specific application and the overall design constraints imposed on the system, those skilled in the art will recognize how best to implement the functionality described for the processing system.

[0125] If implemented in software, the functions can be stored or transmitted as one or more instructions or codes on a computer-readable medium. 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 otherwise. Computer-readable media includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on the machine-readable storage medium. The computer-readable storage medium may be coupled to the processor so that the processor can read and write information to / from the storage medium. Alternatively, the storage medium may be integrated into the processor. As an example, the machine-readable medium may include a transmission line, a data-modulated carrier wave, and / or a separate computer-readable storage medium containing instructions stored thereon, all accessible to the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any portion thereof may be integrated into the processor, such as caches and / or general-purpose register files. 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, disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be implemented in computer program products.

[0126] Software modules may comprise a single instruction or a number of instructions, and may be distributed across several different code segments, across different programs, and across multiple storage media. Computer-readable media may include several software modules. These software modules include instructions that, when executed by an instrument (such as a processor), enable the processing system to perform various functions. These software modules may include transfer modules and receive modules. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, when a trigger event occurs, a software module may be loaded from a hard drive into RAM. During the execution of a software module, the processor may load some instructions into a cache to improve access speed. One or more cache lines may subsequently be loaded into a general-purpose register file for processor execution. In the context of the functionality of a software module described below, it will be understood that such functionality is implemented by the processor when the processor executes the instructions from that software module.

[0127] Similarly, any connection is also legitimately referred to as computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology (such as infrared (IR), radio, and microwave), then that coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is included in the definition of medium. As used herein, disks and discs include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and... Disks, where disks often magnetically reproduce data, and discs optically reproduce data using lasers. Therefore, in some aspects, computer-readable media may include non-transient computer-readable media (e.g., tangible media). Additionally, in 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.

[0128] Therefore, certain aspects may include computer program products for performing the operations described herein. For example, such computer program products may include computer-readable media on which instructions are stored (and / or encoded) that can be executed by one or more processors to perform the operations described herein, such as those for performing the operations described herein and in... Figure 9-11 The instructions for the operation explained in the text.

[0129] Furthermore, it should be understood that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such devices 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, physical storage media such as CDs or floppy disks, etc.) so that the device can obtain the various methods once the storage device is coupled to or provided to the user terminal and / or base station. Furthermore, any other suitable techniques appropriate for providing the methods and techniques described herein to the device may be utilized.

[0130] It will be understood that the claims are not limited to the precise configurations and components described above. Various modifications, substitutions, and variations may be made to the layout, operation, and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A user equipment (UE) for wireless communication, comprising: At least one transceiver is configured to receive from a first base station (BS) serving the UE a measurement configuration for measuring one or more signals from one or more second BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs, and wherein the measurement configuration is based on a timing difference between the first BS and the one or more second BSs, wherein the measurement configuration includes an indication of a measurement window, wherein the measurement window is based on the timing difference; At least one processor, the at least one processor being configured to perform a measurement procedure for the one or more signals according to the measurement configuration; as well as At least one memory coupled to the at least one processor.

2. The UE as claimed in claim 1, wherein the timing difference includes at least one of system frame number offset, time slot offset, or symbol offset.

3. The UE of claim 2, wherein at least one of the time slot offset or the symbol offset is based on (i) the subcarrier spacing of one of the one or more second BSs, or (ii) the subcarrier spacing of the first BS, or (iii) the highest subcarrier spacing between the first BS and the one or more second BSs.

4. The UE as claimed in claim 1, wherein: The first BS is associated with a first radio access technology (RAT) and a first duplex mode; The one or more second BSs are associated with a second RAT and a second duplex mode; and The measurement configuration is based on at least one of the first RAT, the first duplex mode, the second RAT, or the second duplex mode.

5. The UE as described in claim 4, wherein: (i) The first RAT is Long Term Evolution (LTE), the first duplex mode is Frequency Division Duplex (FDD), the second RAT is New Radio (NR), and the second duplex mode is Time Division Duplex (TDD); (ii) The first RAT is LTE, the first duplex mode is TDD, the second RAT is NR, and the second duplex mode is TDD; (iii) The first RAT is NR, the first duplex mode is FDD, the second RAT is NR, and the second duplex mode is FDD; or (iv) The first RAT is NR, the first duplex mode is TDD, the second RAT is LTE, and the second duplex mode is FDD.

6. A wireless communication method at a user equipment (UE), comprising: A measurement configuration is received from a first base station (BS) serving the UE for measuring one or more signals from one or more second BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs, and wherein the measurement configuration is based on a timing difference between the first BS and the one or more second BSs, wherein the measurement configuration includes an indication of a measurement window, wherein the measurement window is based on the timing difference; as well as The measurement procedure is performed for the one or more signals according to the measurement configuration.

7. The method of claim 6, wherein the timing difference includes at least one of system frame number offset, time slot offset, or symbol offset.

8. The method of claim 7, wherein at least one of the time slot offset or the symbol offset is based on (i) the subcarrier spacing of one of the one or more second BSs, or (ii) the subcarrier spacing of the first BS, or (iii) the highest subcarrier spacing between the first BS and the one or more second BSs.

9. The method of claim 6, wherein: The first BS is associated with a first radio access technology (RAT) and a first duplex mode; The one or more second BSs are associated with a second RAT and a second duplex mode; and The measurement configuration is based on at least one of the first RAT, the first duplex mode, the second RAT, or the second duplex mode.

10. A network entity for wireless communication, comprising: At least one processor, said at least one processor being configured to: Determine the timing difference between the network entity and one or more base stations (BS), wherein the network entity is in an asynchronous timing configuration relative to the one or more BS; and A measurement configuration for measuring one or more signals from the one or more BSs is determined at least in part based on the timing difference between the network entity and the one or more BSs, wherein the measurement configuration includes an indication of a measurement window, wherein the measurement window is based on the timing difference; At least one transceiver, the at least one transceiver being configured to transmit the measurement configuration to a user equipment (UE) served by the network entity; as well as At least one memory coupled to the at least one processor.

11. The network entity of claim 10, wherein the timing difference includes at least one of system frame number offset, time slot offset, or symbol offset.

12. The network entity of claim 11, wherein at least one of the time slot offset or the symbol offset is based on (i) the subcarrier spacing of one or more BSs, or (ii) the subcarrier spacing of the network entity, or (iii) the highest subcarrier spacing between the network entity and the one or more BSs.

13. The network entity as claimed in claim 10, wherein: The network entity is associated with a first radio access technology (RAT) and a first duplex mode; The one or more BSs are associated with a second RAT and a second duplex mode; and The measurement configuration is based on at least one of the first RAT, the first duplex mode, the second RAT, or the second duplex mode.

14. The network entity as claimed in claim 13, wherein: The timing difference is a single timing difference value; The at least one transceiver is further configured to transmit a synchronization request to one of the one or more BSs via a network interface between the network entity and the BS, the synchronization request including a first timestamp; The at least one transceiver is further configured to receive a synchronization response from the one BS via the network interface, the synchronization response including at least a second timestamp; and The at least one processor is further configured to set the single timing difference value as the difference between the first timestamp and the second timestamp.

15. The network entity as claimed in claim 14, wherein: The first RAT is Long Term Evolution (LTE) and the first duplex mode is Frequency Division Duplex (FDD); and The second RAT is New Radio (NR) and the second duplex mode is Time Division Duplex (TDD).

16. The network entity as claimed in claim 14, wherein: The first RAT is Long Term Evolution (LTE) and the first duplex mode is Time Division Duplex (TDD); and The second RAT is New Radio (NR) and the second duplex mode is TDD.

17. The network entity as claimed in claim 14, wherein: The at least one processor is further configured to determine the measurement window based on the single timing difference.

18. The network entity as claimed in claim 13, wherein: The timing difference includes multiple timing difference values; The at least one transceiver is further configured to transmit a synchronization request to each of the one or more BSs via a network interface between the network entity and each of the one or more BSs, the synchronization request including a first timestamp; The at least one transceiver is further configured to receive a synchronization response from each of the one or more BSs via the network interface, the synchronization response including at least a second timestamp; and The at least one processor is further configured to: set different timing differences among the plurality of timing differences for each second timestamp received from the second BS as the difference between the first timestamp and the second timestamp.

19. The network entity as claimed in claim 18, wherein: The first RAT is a New Radio (NR) and the first duplex mode is Frequency Division Duplex (FDD); and The second RAT is NR and the second duplex mode is FDD.

20. The network entity as claimed in claim 18, wherein: The first RAT is a New Radio (NR) and the first duplex mode is Time Division Duplex (TDD); and The second RAT is Long Term Evolution (LTE) and the second duplex mode is Frequency Division Duplex (FDD).

21. The network entity as claimed in claim 18, wherein: The at least one processor is further configured to determine the measurement window based on the plurality of timing differences.

22. The network entity of claim 21, wherein the measurement window is based on the sum of the plurality of timing differences.

23. The network entity of claim 21, wherein the at least one processor is further configured to select one or more BSs from a plurality of BSs adjacent to the network entity.

24. The network entity of claim 23, wherein the one or more BSs are selected based on at least one of the location of the UE or the signal strength of the BS.

25. A wireless communication method at a first base station (BS), comprising: Determine the timing difference between the first BS and one or more second BSs, wherein the first BS is in an asynchronous timing configuration relative to the one or more second BSs; A measurement configuration for measuring one or more signals from the one or more second BSs is determined at least in part based on the timing difference between the first BS and the one or more second BSs, wherein the measurement configuration includes an indication of a measurement window, wherein the measurement window is based on the timing difference; as well as The measurement configuration is signaled to the user equipment (UE) served by the first BS.

26. The method of claim 25, wherein: The timing difference includes at least one of system frame number offset, time slot offset, or symbol offset; and At least one of the time slot offset or the symbol offset is based on (i) the subcarrier spacing of one or more second BSs, or (ii) the subcarrier spacing of the first BS, or (iii) the highest subcarrier spacing between the first BS and the one or more second BSs.

27. The method of claim 25, wherein: The first BS is associated with a first radio access technology (RAT) and a first duplex mode; The one or more second BSs are associated with a second RAT and a second duplex mode; and The measurement configuration is based on at least one of the first RAT, the first duplex mode, the second RAT, or the second duplex mode.

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