WO2021138798A1

WO2021138798A1 - Idle search and measurement modifications due to unreliable measurement time configuration

Info

Publication number: WO2021138798A1
Application number: PCT/CN2020/070639
Authority: WO
Inventors: Arvind Vardarajan Santhanam; Sumit Kumar Singh; Ling Xie; Vishal HINGORANI; Preeti SIVAKUMAR
Original assignee: Qualcomm Incorporated
Priority date: 2020-01-07
Filing date: 2020-01-07
Publication date: 2021-07-15

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a wireless network associated with a first radio access technology (RAT), a synchronization signal block (SSB) measurement time configuration (SMTC) for a frequency associated with a second RAT. The UE may detect one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT. The UE may measure the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the received SMTC. Numerous other aspects are provided.

Description

IDLE SEARCH AND MEASUREMENT MODIFICATIONS DUE TO UNRELIABLE MEASUREMENT TIME CONFIGURATION

TECHNICAL FIELD

Aspects of the technology described below generally relate to wireless communication and to techniques and apparatuses for idle search and measurement modifications due to unreliable measurement time configuration. Some techniques and apparatuses described herein enable and provide wireless communication devices and systems configured for enhanced network coverage and efficient power usage.

INTRODUCTION

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, and/or the like) . Examples of such multiple-access technologies include 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, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE) . LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP) .

A wireless communication network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs) . A user equipment (UE) may communicate with a base station (BS) via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. A BS may be referred to as a Node B, a gNB, an access point (AP) , a radio head, a transmit receive point (TRP) , a New Radio (NR) BS, a 5G Node B, and/or the like.

Multiple access technologies have been adopted in various telecommunication standards. Wireless communication standards provide common protocols to enable different devices (e.g., user equipment) to communicate on a municipal, national, regional, and even global level. New Radio (NR) , which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP) . As demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and NR technologies. These improvements can apply to other multiple access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY OF SOME EXAMPLES

The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. The purpose of the summary is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

In some cases, a UE may measure one or more synchronization signal blocks (SSBs) during operation. Measurements can take place in connection with radio resource management, beam management, and/or the like. For example, the UE may measure SSBs of one or more cells to assist with a cell search, a neighbor cell search, a cell selection, a cell reselection, a handover, a serving cell beam sweeping operation, and/or the like. In general, SSBs may generally be transmitted in groups, which may be referred to as SS bursts or SS burst sets. SS bursts may have a periodicity based at least in part on a time spacing between SSB transmissions. Accordingly, to enable the UE to measure SSBs in connection with radio resource management, beam management, and/or the like, a UE may be configured with an SSB measurement timing configuration (SMTC) . An SMTC parameter can indicate a periodicity, a time length, and/or an offset of SSB measurement occasions (e.g., occasions in which one or more base stations transmit SSBs to be measured by the UE) .

In some circumstances, multiple wireless networks may be deployed within an overlapping or same area or region. Multiple network deployments in a common space can support UEs having different data requirements, communication capabilities, operator subscriptions, and/or the like. For example, an LTE network and an NR network may be deployed in a particular region by the same mobile network operator (MNO) or different MNOs. In some situations, multiple network deployment in a common area can present challenges.

As 5G/NR networks are deployed, situations will exist where 5G networks co-exist with each other or with other types of networks. For example, when a UE camps on a serving cell associated with an LTE network, a base station associated with the LTE network may transmit signaling (e.g., a system information block (SIB) ) to advertise one or more NR frequencies and to provide the UE with an SMTC that indicates a periodicity, a duration, and an offset of SSBs transmitted on the NR frequencies. For example, the periodicity, duration, and offset indicated in the SMTC provided by the LTE network may be defined with respect to system frame number (SFN) zero on the LTE network. Accordingly, UEs may use the periodicity, duration, and offset indicated in the SMTC provided by the LTE network to determine a location (e.g., a time window) in which to capture samples of the SSBs transmitted on the NR frequencies with respect to SFN zero on the LTE network. For example, the UEs may capture the SSB samples to obtain LTE-to-NR (L2NR) measurements while in an idle mode on the LTE network to enable reselection to the NR network (e.g., after an evolved packet system (EPS) fallback voice over LTE (VoLTE) call has ended) . For example, the UEs may determine a time window in which to perform a search to detect one or more cells on the NR frequencies and in which to schedule L2NR measurements on NR frequencies in which one or more cells are detected based at least in part on the periodicity, duration, and offset indicated in the SMTC configured by the LTE network.

However, in some cases, the LTE network may incorrectly determine the locations or positions in which NR SSBs are transmitted, which may result in an SMTC having a periodicity, duration, and/or offset that is misconfigured with respect to the SFN on the LTE network. For example, in an LTE network, a UE may be guaranteed to detect a cell from radio frequency (RF) samples captured over any five millisecond period due to the numerology associated with primary synchronization signal and secondary synchronization signal transmissions. However, LTE networks are generally asynchronous with respect to other LTE networks and with respect to NR networks. For example, the LTE networks and the NR networks may have independent oscillators that may drift independently from one another (e.g., up to 0.1 microseconds per second) . Accordingly, the LTE network may not know exactly when SSBs are transmitted on NR frequencies, and even if the LTE network happens to configure an SMTC with a periodicity, duration, and offset that coincides with SSB transmissions on the NR frequencies, the SMTC may become inaccurate or otherwise unreliable over time as the independent time drifts on the LTE network and the NR frequencies accumulate. Consequently, a UE may be unable to detect and/or measure a cell on the NR frequencies and may become trapped on the LTE network (e.g., unable to reselect to the NR network) in cases where the periodicity, duration, and/or offset indicated in the SMTC are incorrect, where the LTE network does not configure an SMTC, or where the SMTC is otherwise unreliable.

Some techniques and apparatuses described herein relate to idle search and measurement modifications to address timing challenges. In some arrangements or deployments, aspects may be implemented by a UE due to an unreliable measurement time configuration, such as an SMTC provided by an LTE network that indicates a periodicity, a duration, and an offset for SSB transmissions on an NR frequency. For example, in some aspects, a UE may receive an SMTC that indicates a periodicity, duration, and offset for SSB transmissions on an NR frequency from one or more base stations associated with an LTE network, and the UE may perform a search to detect one or more SSB spans across one or more cells in the NR frequency over a first time window that corresponds to a configured periodicity associated with the NR frequency (e.g., 20 milliseconds) . Accordingly, the UE may be guaranteed to detect SSB samples from any cells that are operating on the NR frequency over the first time window. In some aspects, the UE may then determine a second time window in which to measure the one or more cells in the NR frequency depending on whether the detected SSB spans are within a time window indicated in the network-configured SMTC. For example, the second time window may have a duration and an offset determined from the network-configured SMTC if all detected SSB spans are within a time window indicated in the network-configured SMTC. Otherwise, if the detected SSB spans are at least partially outside the time window indicated in the network-configured SMTC, the second time window may be determined to cover a union of the SSB spans of all detected cells. Additionally, or alternatively, the second time window may be determined to cover a union of a subset of the detected SSB spans that satisfy a threshold (e.g., having a signal strength that exceeds a threshold, is within a threshold of a network-configured reselection threshold, and/or the like) . In this way, the UE may detect and measure one or more NR cells on an NR frequency (e.g., while in an idle mode on the LTE network) even if the LTE network has misconfigured or not configured an SMTC for the NR frequency, which enables the UE to camp on the one or more NR cells, reselect to the NR cell (s) , conserve power that would otherwise be consumed using a misconfigured SMTC, and/or the like.

In some aspects, a method of wireless communication, performed by a UE, may include: receiving, from a wireless network associated with a first radio access technology (RAT) , an SMTC for a frequency associated with a second RAT; detecting one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and measuring the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.

In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: receive, from a wireless network associated with a first RAT, an SMTC for a frequency associated with a second RAT; detect one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and measure the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to: receive, from a wireless network associated with a first RAT, an SMTC for a frequency associated with a second RAT; detect one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and measure the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.

In some aspects, an apparatus for wireless communication may include: means for receiving, from a wireless network associated with a first RAT, an SMTC for a frequency associated with a second RAT; means for detecting one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and means for measuring the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can be understood in detail, a more particular description is provided herein, with some aspects of the disclosure being illustrated in the appended drawings. However, the appended drawings illustrate only some aspects of this disclosure and are therefore not to be considered limiting of the scope of the disclosure. The same reference numbers in different drawings may identify the same or similar elements.

Fig. 1 is a block diagram conceptually illustrating an example of a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 2 is a block diagram conceptually illustrating an example of a base station in communication with a UE in a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 3A is a block diagram conceptually illustrating an example of a frame structure in a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 3B is a block diagram conceptually illustrating an example synchronization communication hierarchy in a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 4 is a block diagram conceptually illustrating an example slot format with a normal cyclic prefix, in accordance with various aspects of the present disclosure.

Fig. 5 is a block diagram conceptually illustrating an example network architecture via which a multi-mode UE may operate, in accordance with various aspects of the present disclosure.

Figs. 6A-6B are diagrams illustrating one or more examples of idle search and measurement modifications due to an unreliable measurement time configuration, in accordance with various aspects of the present disclosure.

Fig. 7 is a diagram illustrating an example process performed, for example, by a UE, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and/or the like (collectively referred to as “elements” or “features” ) . These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

While some aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and/or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, and/or the like) . While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including one or more antennas, RF-chains, power amplifiers, modulators, buffers, processors, interleavers, adders/summers, and/or the like) . It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

Fig. 1 is a diagram illustrating a wireless network 100 in which aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include a number of BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with user equipment (UEs) and may also be referred to as a base station, a NR BS, a Node B, a gNB, a 5G node B (NB) , an access point, a transmit receive point (TRP) , and/or the like. Each BS may provide communication coverage for a particular area (e.g., a fixed or changing geographical area) . In some scenarios, BSs 110 may be stationary or non-stationary. In some non-stationary scenarios, mobile BSs 110 may move with varying speeds, direction, and/or heights. In 3GPP, the term “cell” can refer to a coverage area of a BS 110 and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. Additionally, or alternatively, a BS may support access to an unlicensed RF band (e.g., a wireless local area network (WLAN) band and/or the like) . A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG) ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in Fig. 1, a BS 110a may be a macro BS for a macro cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a BS 110c may be a femto BS for a femto cell 102c. A BS may support one or multiple (e.g., three) cells. The terms “eNB” , “base station” , “NR BS” , “gNB” , “TRP” , “AP” , “node B” , “5G NB” , and “cell” may be used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, and/or the like using any suitable transport network. In other scenarios, BSs may be implemented in a software defined network (SDN) manner or via network function virtualization (NFV) manner.

Wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that can relay transmissions for other UEs. In the example shown in Fig. 1, a relay station 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communication between BS 110a and UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 Watts) .

A network controller 130 may couple to a set of BSs and may provide coordination and control for these BSs. Network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with one another, e.g., directly or indirectly via a wireless or wireline backhaul.

UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, and/or the like. A UE may be a cellular phone (e.g., a smart phone) , a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet) ) , an entertainment device (e.g., a music or video device, or a satellite radio) , a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, robotics, drones, implantable devices, augmented reality devices, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, and/or the like, that may communicate with a base station, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE) . UE 120 may be included inside a housing that houses components of UE 120, such as processor components, memory components, and/or the like. These components may be integrated in a variety of combinations and/or may be stand-alone, distributed components considering design constraints and/or operational preferences.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, and/or the like. A frequency may also be referred to as a carrier, a frequency channel, and/or the like. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another) . For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, and/or the like) , a mesh network, and/or the like. In this case, the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110. A UE performing scheduling operations can include or perform base-station-like functions in these deployment scenarios.

As indicated above, Fig. 1 is provided merely as an example. Other examples may differ from what is described with regard to Fig. 1.

Fig. 2 shows a block diagram of a design 200 of base station 110 and UE 120, which may be one of the base stations and one of the UEs in Fig. 1. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T ≥ 1 and R ≥ 1. The T and R antennas may be configured with multiple antenna elements formed in an array for MIMO or massive MIMO deployments that can occur in millimeter wave (mmWave or mmW) communication systems.

At base station 110, a transmit processor 220 can carry out a number of functions associated with communications. For example, transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS (s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI) and/or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and/or the like) and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., the cell-specific reference signal (CRS) ) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS) ) . A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM and/or the like) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively. According to various aspects described in more detail below, the synchronization signals can be generated with location encoding to convey additional information.

At UE 120, antennas 252a through 252r may receive downlink RF signals. The downlink RF signals may be received from and/or may be transmitted by one or more base stations 110. The signals can be provided to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM and/or the like) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. A channel processor may determine reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , and/or the like. In some aspects, one or more components of UE 120 may be included in a housing.

For uplink communications, a UE 120 may transmit control information and/or data to another device, such as one or more base stations 110. For example, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, and/or the like) , and transmitted to base station 110. At base station 110, the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240. Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244. Network controller 130 may include communication unit 294, controller/processor 290, and memory 292.

Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform one or more techniques associated with idle search and measurement modifications due to an unreliable measurement time configuration, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform or direct operations of, for example, process 700 of Fig. 7 and/or other processes as described herein.

Memories

242 and 282 may store data and program codes for base station 110 and UE 120, respectively. A scheduler 246 may schedule UEs for data transmission on the downlink and/or uplink.

In some aspects, the UE 120 may include a variety of means or components for implementing communication functions. For example, the variety of means may include means for receiving, from a wireless network associated with a first RAT, an SMTC for a frequency associated with a second RAT, means for detecting one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT, means for measuring the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT, and/or the like.

In some aspects, the UE 120 may include a variety of structural components for carrying out functions of the various means. For example, structural components that carry out functions of such means may include one or more components of UE 120 described in connection with Fig. 2, such as antenna 252, DEMOD 254, MOD 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, controller/processor 280, and/or the like.

As indicated above, Fig. 2 is provided merely as an example. Other examples may differ from what is described with regard to Fig. 2.

Fig. 3A shows an example frame structure 300 for FDD in a telecommunications system (e.g., NR) . The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames (sometimes referred to as frames) . Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms) ) and may be partitioned into a set of Z (Z ≥ 1) subframes (e.g., with indices of 0 through Z-1) . Each subframe may have a predetermined duration (e.g., 1 ms) and may include a set of slots (e.g., 2 ^m slots per subframe are shown in Fig. 3A, where m is a numerology used for a transmission, such as 0, 1, 2, 3, 4, and/or the like) . Each slot may include a set of L symbol periods. For example, each slot may include fourteen symbol periods (e.g., as shown in Fig. 3A) , seven symbol periods, or another number of symbol periods. In a case where the subframe includes two slots (e.g., when m = 1) , the subframe may include 2L symbol periods, where the 2L symbol periods in each subframe may be assigned indices of 0 through 2L–1. In some aspects, a scheduling unit for the FDD may frame-based, subframe-based, slot-based, symbol-based, and/or the like.

While some techniques are described herein in connection with frames, subframes, slots, and/or the like, these techniques may equally apply to other types of wireless communication structures, which may be referred to using terms other than “frame, ” “subframe, ” “slot, ” and/or the like in 5G NR. In some aspects, a wireless communication structure may refer to a periodic time-bounded communication unit defined by a wireless communication standard and/or protocol. Additionally, or alternatively, different configurations of wireless communication structures than those shown in Fig. 3A may be used.

In certain telecommunications (e.g., NR) , a base station may transmit synchronization signals. For example, a base station may transmit a primary synchronization signal (PSS) , a secondary synchronization signal (SSS) , and/or the like, on the downlink for each cell supported by the base station. The PSS and SSS may be used by UEs for cell search and acquisition. For example, the PSS may be used by UEs to determine symbol timing, and the SSS may be used by UEs to determine a physical cell identifier, associated with the base station, and frame timing. The base station may also transmit a physical broadcast channel (PBCH) . The PBCH may carry some system information, such as system information that supports initial access by UEs.

In some aspects, the base station may transmit the PSS, the SSS, and/or the PBCH in accordance with a synchronization communication hierarchy (e.g., a synchronization signal (SS) hierarchy) including multiple synchronization communications (e.g., SS blocks) , as described below in connection with Fig. 3B.

Fig. 3B is a block diagram conceptually illustrating an example SS hierarchy, which is an example of a synchronization communication hierarchy. As shown in Fig. 3B, the SS hierarchy may include an SS burst set, which may include a plurality of SS bursts (identified as SS burst 0 through SS burst B-1, where B is a maximum number of repetitions of the SS burst that may be transmitted by the base station) . As further shown, each SS burst may include one or more SS blocks (SSBs) (identified in Fig. 3B as SS block 0 through SS block (b _{max_SS}-1) , where b _{max_SS}-1 is a maximum number of SSBs that can be carried by an SS burst) . In some aspects, different SSBs may be beam-formed differently. An SS burst set may be periodically transmitted by a wireless node, such as every X milliseconds, as shown in Fig. 3B. In some aspects, an SS burst set may have a fixed or dynamic length, shown as Y milliseconds in Fig. 3B.

The SS burst set shown in Fig. 3B is an example of a synchronization communication set, and other synchronization communication sets may be used in connection with the techniques described herein. Furthermore, an SSB as shown in Fig. 3B is an example of a synchronization communication, and other synchronization communications may be used in connection with the techniques described herein.

In some aspects, an SSB includes resources that carry the PSS, the SSS, the PBCH, and/or other synchronization signals (e.g., a tertiary synchronization signal (TSS) ) and/or synchronization channels. In some aspects, multiple SSBs may be included in an SS burst, and the PSS, the SSS, and/or the PBCH may be the same across each SSB of the SS burst. In some aspects, a single SSB may be included in an SS burst. In some aspects, the SSB may be at least four symbol periods in length, where each symbol carries one or more of the PSS (e.g., occupying one symbol) , the SSS (e.g., occupying one symbol) , and/or the PBCH (e.g., occupying two symbols) .

In some aspects, the symbols of an SSB are consecutive, as shown in Fig. 3B. In some aspects, the symbols of an SSB are non-consecutive. Similarly, in some aspects, one or more SSBs of the SS burst may be transmitted in consecutive radio resources (e.g., consecutive symbol periods) during one or more slots. Additionally, or alternatively, one or more SSBs of the SS burst may be transmitted in non-consecutive radio resources.

In some aspects, the SS bursts may have a burst period, whereby the SSBs of the SS burst are transmitted by the base station according to the burst period. In other words, the SSBs may be repeated during each SS burst. In some aspects, the SS burst set may have a burst set periodicity, whereby the SS bursts of the SS burst set are transmitted by the base station according to the fixed burst set periodicity. In other words, the SS bursts may be repeated during each SS burst set.

The base station may transmit system information, such as system information blocks (SIBs) on a physical downlink shared channel (PDSCH) in certain slots. The base station may transmit control information/data on a physical downlink control channel (PDCCH) in C symbol periods of a slot, where B may be configurable for each slot. The base station may transmit traffic data and/or other data on the PDSCH in the remaining symbol periods of each slot.

As indicated above, Figs. 3A and 3B are provided as examples. Other examples may differ from what is described with regard to Figs. 3A and 3B.

Fig. 4 shows an example slot format 400 with a normal cyclic prefix. The available time frequency resources may be partitioned into resource blocks. Each resource block may cover a set of subcarriers (e.g., 12 subcarriers) in one slot and may include a number of resource elements. Each resource element may cover one subcarrier in one symbol period (e.g., in time) and may be used to send one modulation symbol, which may be a real or complex value.

An interlace structure may be used for each of the downlink and uplink for FDD in certain telecommunications systems (e.g., NR) . For example, Q interlaces with indices of 0 through Q –1 may be defined, where Q may be equal to 4, 6, 8, 10, or some other value. Each interlace may include slots that are spaced apart by Q frames. In particular, interlace q may include slots q, q + Q, q + 2Q, etc., where q ∈ {0, …, Q –1} .

A UE may be located within the coverage of multiple BSs. One of these BSs may be selected to serve the UE. The serving BS may be selected based at least in part on various criteria such as received signal strength, received signal quality, path loss, and/or the like. Received signal quality may be quantified by a signal-to-noise-and-interference ratio (SNIR) , or a reference signal received quality (RSRQ) , or some other metric. The UE may operate in a dominant interference scenario in which the UE may observe high interference from one or more interfering BSs.

While aspects of the examples described herein may be associated with New Radio (NR) or 5G technologies, aspects of the present disclosure may be applicable with other wireless communication systems. NR may refer to radios configured to operate according to a new air interface (e.g., other than Orthogonal Frequency Divisional Multiple Access (OFDMA) -based air interfaces) or fixed transport layer (e.g., other than Internet Protocol (IP) ) . In some aspects, NR may utilize OFDM with a CP (herein referred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDM on the uplink, may utilize CP-OFDM on the downlink and include support for half-duplex operation using TDD. In some aspects, NR may, for example, utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink and include support for half-duplex operation using TDD. NR may include Enhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g., 80 megahertz (MHz) and beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 60 gigahertz (GHz) ) , massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra reliable low latency communications (URLLC) service.

In some aspects, a single component carrier bandwidth of 100 MHz may be supported. NR resource blocks may span 12 sub-carriers with a sub-carrier bandwidth of 60 or 120 kilohertz (kHz) over a 0.1 millisecond (ms) duration. Each radio frame may include 40 slots and may have a length of 10 ms. Consequently, each slot may have a length of 0.25 ms. Each slot may indicate a link direction (e.g., DL or UL) for data transmission and the link direction for each slot may be dynamically switched. Each slot may include DL/UL data as well as DL/UL control data.

Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells. Alternatively, NR may support a different air interface, other than an OFDM-based interface. NR networks may include entities such as central units or distributed units.

As indicated above, Fig. 4 is provided as an example. Other examples may differ from what is described with regard to Fig. 4.

Fig. 5 is a block diagram conceptually illustrating an example network architecture 500 via which a multi-mode UE may operate, in accordance with various aspects of the present disclosure.

As shown in Fig. 5, a UE 505 may be capable of accessing different core networks via different access nodes. The access nodes may include, for example, a gNB 510, an eNB 515, a wireless local area network (WLAN) access point (AP) 520, a Global System for Mobile communications (GSM) Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN) and/or UMTS Terrestrial Radio Access Network (UTRAN) access node 525, and/or the like. The core networks may include, for example, a 5G/NR core network (5GC) 530, an evolved packet core (EPC) 535 of a 4G/LTE network, a circuit switched core network (2G/3G CN) 545 of a 2G and/or 3G network, and/or the like.

As further shown in Fig. 5, the gNB 510 may provide access to the 5GC 530, the eNB 515 may provide access to the EPC 535, the WLAN AP 520 may provide access to the 5GC 530 and/or the EPC 535 via an evolved packet data gateway (ePDG) and/or via a non-3GPP interworking function (N3IWF) device 540, and the GERAN/UTRAN access node 525 may provide access to the 2G/3G CN 545. As further shown in Fig. 5, network devices of the 5GC 530 and/or the EPC 535 may communicate with an Internet Protocol (IP) Multimedia Subsystem (IMS) entity 550 (e.g., for IMS registration and/or communication via an IMS protocol) . In some aspects, one or more of the gNB 510, the eNB 515, and/or the GERAN/UTRAN 525 may correspond to the base station 110 described elsewhere herein.

In some aspects, the UE 505 may correspond to the UE 120 described elsewhere herein. The UE 505 may be a multi-mode UE capable of communicating via multiple radio access technologies (RATs) , such as an NR RAT (e.g., via the gNB 510, via the 5GC 530, and/or the like) , an LTE RAT (e.g., via the eNB 515 and/or the EPC 535) , a WLAN RAT (e.g., via the WLAN AP 520 and/or the ePDG/N3IWF 540) , a circuit-switched (CS) RAT (e.g., via the GERAN/UTRAN access node 525 and/or the 2G/3G CN 545) , and/or the like.

In some aspects, the NR RAT may be an NR RAT that uses an NR core network (e.g., 5GC 530) and an NR access network (e.g., via gNB 510) . In some aspects, the NR RAT may be an NR RAT that uses an NR core network (e.g., 5GC 530) and an LTE access network (e.g., via eNB 515 and/or gNB 510) . Additionally, or alternatively, the NR RAT may be an NR RAT in a standalone (SA) mode (e.g., an NR SA mode) or a non-standalone (NSA) mode (e.g., an NR NSA mode) . In some aspects, the NR RAT and/or the LTE RAT may use an IMS protocol and/or an NAS protocol for one or more service requests. In some aspects, the LTE RAT may be an LTE-only RAT where the eNB 515 is connected to the EPC 535 in an SA mode (e.g., an LTE SA mode) without 5G secondary carriers. In some aspects, the LTE RAT may be an LTE NSA RAT where the eNB 515 is connected to a 5GC 530 in an LTE/NR NSA mode with 5G secondary carriers capable of being added to a 4G primary carrier, which may also be referred to as an Evolved UMTS Terrestrial Radio Access (EUTRA) -NR Dual Connectivity (ENDC) mode. In some aspects, the CS RAT may include a 3G RAT, a 2G RAT, and/or the like.

As indicated above, Fig. 5 is provided merely as an example. Other examples may differ from what is described with regard to Fig. 5.

In some cases, a UE may measure one or more synchronization signal blocks (SSBs) during operation. For example, the UE may measure SSBs of one or more cells to assist with a cell search, a neighbor cell search, a cell selection, a cell reselection, a handover, a serving cell beam sweeping operation, and/or the like. In general, SSBs may generally be transmitted in groups, which may be referred to as SS bursts or SS burst sets. Accordingly, to enable the UE to measure SSBs in connection with radio resource management, beam management, and/or the like, a UE may be configured with an SSB measurement timing configuration (SMTC) . An SMTC parameter can indicate a periodicity, a time length, and/or an offset of SSB measurement occasions (e.g., occasions in which one or more base stations transmit SSBs to be measured by the UE) . In some circumstances, multiple wireless networks may be deployed within an overlapping or same area or region. Multiple network deployments in a common space can support UEs having different data requirements, communication capabilities, operator subscriptions, and/or the like. For example, an LTE network and an NR network may be deployed in a particular region by the same mobile network operator (MNO) or different MNOs. In some situations, multiple network deployment in a common area can present challenges.

As 5G/NR networks are deployed, situations will exist where 5G networks co-exist with each other or with other types of networks. For example, when a UE camps on a serving cell associated with an LTE network, a base station associated with the LTE network may transmit signaling (e.g., a system information block (SIB) ) to advertise one or more NR frequencies and to provide the UE with an SMTC that indicates a periodicity, a duration, and an offset of SSBs transmitted on the NR frequencies. For example, the periodicity, duration, and offset indicated in the SMTC provided by the LTE network may be defined with respect to system frame number (SFN) zero on the LTE network. Accordingly, UEs may use the periodicity, duration, and offset indicated in the SMTC provided by the LTE network to determine a location (e.g., a time window) in which to capture samples of the SSBs transmitted on the NR frequencies with respect to SFN zero on the LTE network. However, in some cases, the LTE network may incorrectly determine the locations or positions in which NR SSBs are transmitted, which may result in an SMTC having a periodicity, duration, and/or offset that is misconfigured with respect to the SFN on the LTE network.

Some techniques and apparatuses described herein relate to idle search and measurement modifications to address timing challenges. In some arrangements or deployments, aspects may be implemented by a UE due to an unreliable measurement time configuration, such as an SMTC provided by an LTE network that indicates a periodicity, a duration, and an offset for SSB transmissions on an NR frequency. For example, in some aspects, a UE may receive an SMTC that indicates a periodicity, duration, and offset for SSB transmissions on an NR frequency from one or more base stations associated with an LTE network, and the UE may perform a search to detect one or more SSB spans across one or more cells in the NR frequency over a first time window that corresponds to a configured periodicity associated with the NR frequency (e.g., 20 milliseconds) . Accordingly, the UE may be guaranteed to detect SSB samples from any cells that are operating on the NR frequency over the first time window. In some aspects, the UE may then determine a second time window in which to measure the one or more cells in the NR frequency depending on whether the detected SSB spans are within a time window indicated in the network-configured SMTC. For example, the second time window may have a duration and an offset determined from the network-configured SMTC if all detected SSB spans are within a time window indicated in the network-configured SMTC. Otherwise, if the detected SSB spans are at least partially outside the time window indicated in the network-configured SMTC, the second time window may be determined to cover a union of the SSB spans of all detected cells or a subset of the detected SSB spans that satisfy a threshold (e.g., having a signal strength that exceeds a threshold, is within a threshold of a network-configured reselection threshold, and/or the like) . In this way, the UE may detect and measure one or more NR cells on an NR frequency even if the LTE network has misconfigured or not configured an SMTC for the NR frequency,

Figs. 6A-6B are diagrams illustrating one or more examples 600 of idle search and measurement modifications according to some aspects. In some instances, these may be due to an unreliable measurement time configuration. As shown in Figs. 6A-6B, example (s) 600 may include a UE 120 in communication with a first base station 110a (e.g., an eNB) that provides access to a first wireless network (e.g., an LTE network) using a first radio access technology (RAT) (e.g., LTE) . Also as shown, example (s) 600 may include a second base station 110b (e.g., a gNB) that provides access to a second wireless network (e.g., an NR network) using a second RAT (e.g., NR) . For example, in some aspects, the UE 120 and the base stations 110 may operate in a 5G/NR standalone (SA) mode, a 5G/NR non-standalone (NSA) mode, and/or the like, as described above in connection with Fig. 5.

Although example (s) 600 may be described herein in a context where the first RAT is an LTE RAT and the second RAT is an NR RAT, other RAT types may be used in connection with example (s) 600 described herein. For example, in some aspects, the second RAT may be a later generation RAT and the first RAT may be an earlier generation RAT (e.g., that assists with establishing a radio access network connection for the second RAT) , or vice versa. Similarly, although the first base station 110a is described herein as an eNB and the second base station 110b is described herein as a gNB, other base stations 110 may be used in connection with example (s) 600 described herein. For example, in some aspects, the first base station 110a may be an earlier generation base station 110 and the second base station 110b may be a later generation base station 110.

As shown in Fig. 6A, and by reference number 610, the base station 110a may transmit, and the UE 120 may receive, signaling (e.g., a SIB) . Signaling can include a network-configured SMTC, which may indicate a periodicity, an offset, and a duration for one or more SSBs that are transmitted by the second base station 110b on an NR frequency. For example, as described above, the periodicity, offset, and duration indicated in the network-configured SMTC may generally be defined with respect to SFN zero on a wireless network associated with the first base station 110a. Accordingly, in a conventional deployment, the UE 120 would perform a search to detect one or more cells and subsequently measure one or more detected cells on the NR frequency over a time window that is determined from the periodicity, offset, and duration indicated in the network-configured SMTC. Yet as described above, in some cases the network-configured SMTC may be misconfigured with incorrect values, initially configured with correct values that become incorrect over time due to drift that accumulates independently on the LTE network and the NR frequencies, and/or the like.

As described herein, communication devices (e.g., the UE 120) may perform an idle search and measurement procedure (e.g., an L2NR procedure) . The procedure can include one or more parameters used to perform cell detection and/or measurement are independent of the network-configured SMTC. Also, in some aspects, the UE 120 may compute the one or more parameters to perform the cell detection and/or measurement while in idle mode, as described herein, or the UE 120 may utilize one or more parameters that the UE 120 computed while in connected mode (e.g., based on an NR measurement object and/or other suitable techniques) after transitioning from connected mode to idle mode.

As further shown in Fig. 6A, and by reference number 612, the UE 120 may perform a search to detect one or more SSB bursts or spans. The SSB signaling can be transmitted on an NR frequency over a first time window that is based at least in part on a configured periodicity for the NR frequency. For example, in some aspects, a configured periodicity may be a preconfigured value, such as 20 milliseconds, that is guaranteed to cover a time period in which the second base station 110b transmits SSBs regardless of the periodicity indicated in the network-configured SMTC. Any offset indicated in the network-configured SMTC may be ignored. And the first time window in which the UE 120 performs the search to detect the one or more SSB spans may start from SFN zero on the LTE network. Accordingly, in some aspects, the UE 120 may start to capture RF samples from SFN zero on the LTE network and continue to capture RF samples until the first time window has elapsed. For example, as further shown in Fig. 6A, and by reference number 614, the second base station 110b may transmit one or more SSBs on the NR frequency according to a particular periodicity, and the periodic SSB transmissions may generally occur at some point in the first time window in which the UE 120 performs the search to detect the one or more SSB spans. In some aspects, if the UE 120 detects one or more cells during the cell search phase, the UE 120 may schedule measurements on the one or more cells. Alternatively, if the UE 120 does not detect any cells during the cell search phase, the UE 120 may return to the idle mode on the LTE network and perform the cell search again at a later time.

As further shown in Fig. 6A, and by reference number 616, the UE 120 may measure one or more cells in the NR frequency. Measurement can occur during or over a second time window. This second time window may correspond to a time window that has a duration and an offset that is determined based at least in part on whether the SSB spans detected in the cell search phase (if any) are within the network-configured SSB duration. For example, the network-configured SSB duration may have a duration that is indicated in the network-configured SMTC, and may have an offset (with respect to SFN zero) that is indicated in the network-configured SMTC. Accordingly, in cases where the SSB spans detected in the cell search phase all fall within the network-configured SSB duration, the second time window in which the UE 120 measures the one or more cells in the NR frequency may be determined based at least in part on the offset and duration indicated in the network-configured SMTC. Otherwise, in cases where the SSB spans detected in the cell search phase at least partially fall outside the network-configured SSB duration, the UE 120 may determine an altered duration and/or an altered offset for the second time window that covers a union of all SSB spans detected in the cell search phase. Additionally, or alternatively, the second time window may have an altered duration and/or an altered offset that is determined to cover a union of a subset of the detected SSB spans that satisfy a threshold (e.g., having a signal strength that exceeds an RSRP threshold, an RSRQ threshold, a SNIR threshold, and/or the like or is within a threshold of a reselection threshold configured by base station 110a and/or 110b, and/or the like) .

As shown in Fig. 6B, and by reference number 620, the first time window in which the UE 120 performs a search to detect one or more SSB spans in an NR frequency may have a duration that is based at least in part on a configured periodicity for the NR frequency. As described above, the first time window (which may be referred to herein as a search window) may start at SFN zero on the LTE network and may have a duration, such as 20 milliseconds, that is guaranteed to cover a time period in which the SSB spans will be transmitted regardless of a periodicity indicated in a network-configured SMTC. Accordingly, the UE 120 may capture RF samples over the search window, whereby SSBs that are transmitted in the NR frequency anywhere within the search window may be detected by the UE 120. In some aspects, if the UE 120 detects one or more SSBs (and therefore detects one or more cells) within the search window, the UE 120 may determine a second time window in which to measure the one or more cells. For example, as further shown in Fig. 6B, and by reference number 622, the UE 120 may determine a network-configured SSB duration based at least in part on the duration and offset indicated in the network-configured SMTC (e.g., the network-configured SSB duration may have a duration that equals the duration indicated in the network-configured SMTC, and the offset indicated in the network-configured SMTC may define a frame boundary at which the network-configuration SSB duration begins) .

As further shown in Fig. 6B, and by reference number 630, the UE 120 may apply the network-configured SMTC to schedule measurements on the one or more cells in the NR frequency when the SSB spans detected in the search phase are all within the SSB duration indicated in the network-configured SMTC. For example, in this case, the UE 120 may detect a first SSB transmitted by a first cell (Cell 1) and a second SSB transmitted by a second cell (Cell 2) , and the first SSB and the second SSB may be detected within SSB spans that are located within the network-configured SSB duration. When the SSB spans that include detected SSBs are all located within the network-configured SSB duration, the network-configured SMTC may be properly aligned with the actual SSB transmissions. The UE 120 may apply the periodicity, duration, and offset parameters indicated in the network-configured SMTC to measure the one or more cells in the NR frequency. But as described above, in some cases, the network-configured SMTC may be misconfigured with incorrect values (e.g., initially configured with correct values that become incorrect over time due to drift accumulation, and/or the like) . Accordingly, in some aspects, the UE 120 may configure an altered SMTC in cases where the SSB spans detected in the cell search phase at least partially fall outside the network-configured SSB duration.

For example, in Fig. 6B, reference number 640 illustrates a case in which detected SSB spans at least partially fall outside a network-configured SSB duration. In this case, the UE 120 may detect three SSBs transmitted by three respective cells (Cell 1 through Cell 3) , and all of the SSBs are within SSB spans that are located outside the network-configured SSB duration. Accordingly, as shown by reference number 642, the UE 120 may determine an altered SSB duration that has a duration to cover a union of the detected SSB spans.

As shown by reference number 644, the UE 120 may determine an altered offset. This altered offset can correspond to an LTE SFN that corresponds to a system frame boundary that is immediately prior to a start time of an earliest SSB span among the SSB spans detected in the cell search phase. In this way, the UE 120 may determine a duration and an offset for the second time window, and the one or more cells may be measured over only the second time window (e.g., to conserve power that would otherwise be consumed obtaining measurements during time periods in which no SSBs are transmitted) . Also in cases where there is a time gap between two or more SSB spans, the UE 120 may opportunistically operate one or more radio components (e.g., an RF chain, baseband, and/or the like) in a low-power state during the time gap (e.g., using a masking function) .

For example, as shown in Fig. 6B, and by reference number 646, the SSB spans detected from the first cell and the second cell overlap with one another, and then there is a time gap between the end of the second SSB span and a start of the third SSB span detected from the third cell. Accordingly, in this case, the UE 120 may operate one or more radio components in a low-power state during the time gap between the end of the second SSB span and the start of the third SSB span (e.g., a time period in which no SSBs are transmitted) .

In some aspects, the UE 120 may determine start and end times for the SSB spans detected in the cell search phase. Time determination can be based at least in part on a master information block (MIB) frame boundary and a half-frame indicator in a decoded physical broadcast channel (PBCH) payload. For example, in some aspects, the MIB frame boundary may indicate a most recent system frame boundary prior to transmission of the PBCH payload, and the half-frame indicator may be set to a first value (e.g., zero) if the PBCH payload is transmitted in the first half of a frame, or to a second value (e.g., one) if the PBCH payload is transmitted in the second half of a frame. Accordingly, if the half-frame indicator is set to the first value to indicate that the PBCH payload is transmitted in the first half of a frame, the UE 120 may determine that a start time of the SSB span corresponds to the MIB frame boundary in the decoded PBCH payload. Alternatively, if the half-frame indicator is set to the second value to indicate that the PBCH payload is transmitted in the second half of the frame, the UE 120 may determine that the start time of the SSB span corresponds to the MIB frame boundary plus a time value that corresponds to a half-frame (e.g., five milliseconds in the case of a ten millisecond frame) . Furthermore, the end time of the SSB span may be determined by summing the start time of the SSB span and a duration of the SSB span, which may be determined based at least in part on a fixed number of beams on a per-band basis and a subcarrier spacing signaled by the network (e.g., via base station 110a and/or 110b) . For example, in some aspects, the UE 120 may determine the SSB span using a lookup table, which in one example may be configured as follows:

Beams (L)	Subcarrier spacing (SCS)	SSB Span
4	15 kHz	2 ms
4	30 kHz	1 ms
8	15 kHz	4 ms
8	30 kHz	2 ms
64	120 kHz	5 ms
64	240 kHz	2.5 ms

Table 1 -SSB span lookup table

In some aspects, in cases where the UE 120 configures an altered SMTC in which the offset and/or duration differ from the offset and/or duration indicated in the network-configured SMTC, the UE 120 may release the altered SMTC when one or more conditions are satisfied. For example, the altered SMTC may be released if the UE 120 fails to detect a cell over a configured quantity of search and/or measurement periods, if the LTE network disables L2NR reselection for the NR frequency associated with the altered SMTC, the UE 120 moves to a cell in which an SMTC is not configured for the NR frequency, after a configured time period, and/or the like.

In some aspects, in cases where the UE 120 includes multiple subscriber identity modules (SIM) , the idle search and measurement modifications described herein may be applied for one or more of the SIMs and/or dependent on a status of one or more of the SIMs. For example, in cases where the UE 120 includes multiple SIMs that are associated with the same mobile network operator (MNO) , an altered duration and/or offset that is determined on an LTE stack for one of the SIMs may be applied to all of the SIMs that are associated with the same MNO. Additionally, or alternatively, the altered duration and/or offset may be applied on the LTE stack for different SIMs that are associated with different MNOs in cases where the different MNOs provide network-configured SMTCs for the same NR frequency. Furthermore, in some aspects, the idle search and measurement process may be enabled, disabled, or otherwise controlled depending on a status of a service or data activity associated with a particular SIM. For example, if the UE 120 is engaged in a high-priority service associated with one SIM, such as a VoLTE call, the idle search and measurement process described herein may be disabled on the other SIM (s) until the high-priority service has ended. Additionally, or alternatively, the idle search and measurement process described herein may be disabled or throttled (e.g., performed less often) for a subscription associated with one SIM when data activity on another SIM satisfies a condition (e.g., when data activity is high, associated with a critical or high-priority application, and/or the like) .

In some aspects, crowdsourcing may be applied for the information associated with the idle search and measurement modifications described herein. For example, in some aspects, the UE 120 may transmit information to a server on the LTE network to indicate the actual time period in which to search for and measure SSBs on certain NR frequencies. For example, the UE 120 may transmit information to the server on the LTE network to indicate that all SSB spans detected on an NR frequency are inside the network-configured SSB duration, and other UEs 120 may reference this information to determine that the network-configured SMTC is reliable without having to perform an extended cell search or independently determine whether the network-configured SMTC values are valid. Additionally, or alternatively, in cases where the UE 120 determines an altered duration and/or offset in which to measure SSBs on the NR frequency (e.g., when the SSB spans detected on the NR frequency are at least partially outside the network-configured SSB duration) , the UE 120 may transmit information indicating the altered values for the duration and/or offset. In this way, other UEs 120 may obtain the altered duration and/or offset values from the server without having to perform an extended cell search or independently determine the altered SMTC values. Furthermore, in some aspects, the UE 120 may receive, from the server, information indicating the duration and the offset of the second time window in which to measure the one or more cells on the NR frequency, to leverage crowdsourced information provided by other UEs. In some aspects, the information provided to the server may be associated with a time stamp and a validity period to account for the possibility that the accuracy of the network-configured SMTC and/or the altered SMTC may vary over time (e.g., due to accumulated time drift) .

In some aspects, if the UE 120 moves from a first LTE cell to a second LTE cell, the UE 120 may reuse altered SMTC parameters for an NR frequency that is determined while operating on the first LTE cell after moving to the second LTE cell if the NR frequency is also a reselection frequency in the second LTE cell. For example, as described above, the UE 120 may determine an altered offset and/or an altered duration for measuring SSBs in cases where the SSB spans detected in an NR frequency at least partially fall outside the network-configured SSB duration. In this case, the altered offset and/or altered duration may be determined for the NR frequency with respect to the first LTE cell, and the UE 120 may recompute the altered offset and/or altered duration for the second LTE cell based at least in part on a time delta between the first LTE cell and the second LTE cell (e.g., with respect to SFN zero in the second LTE cell) . In this way, the UE 120 may efficiently determine the appropriate time period in which to search for and measure SSBs while camped on the second LTE cell, which may be asynchronous (not time-aligned) with respect to the first LTE cell, thereby conserving power that would otherwise be consumed by performing an extended initial search to capture SSB samples and determine the altered offset and/or duration for the second LTE cell. Additionally, or alternatively, the UE 120 may conserve power by scheduling the cell search phase once every N scheduling occasions (rather than performing the cell search phase in every scheduling occasion until the first cell is detected) , or by throttling the cell search to occur once in a configurable time period (e.g., once in every 30-second period) . Additionally, or alternatively, the cell search and/or measurement process may be performed less often in cases where an inertial sensor of the UE 120 indicates that the UE 120 is stationary or has moved less than a threshold distance since a previous time when the cell search and/or measurement process was performed.

As indicated above, Figs. 6A-6B are provided as one or more examples. Other examples may differ from what is described with respect to Figs. 6A-6B.

Fig. 7 is a diagram illustrating an example process 700 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 700 is an example where the UE (e.g., UE 120, UE 505, and/or the like) performs operations associated with idle search and measurement modifications due to an unreliable measurement time configuration.

As shown in Fig. 7, in some aspects, process 700 may include receiving, from a wireless network associated with a first RAT, an SMTC for a frequency associated with a second RAT (block 710) . For example, the UE may receive (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller/processor 280, and/or the like) , from a wireless network associated with a first RAT, an SMTC for a frequency associated with a second RAT, as described above.

As further shown in Fig. 7, in some aspects, process 700 may include detecting one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT (block 720) . For example, the UE may detect (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller/processor 280, and/or the like) one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT, as described above.

As further shown in Fig. 7, in some aspects, process 700 may include measuring the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT (block 730) . For example, the UE may measure (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller/processor 280, and/or the like) the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT, as described above.

Process 700 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, process 700 includes setting the second time window to correspond to the SSB duration indicated in the SMTC, based at least in part on determining that the one or more SSB spans are all within the SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.

In a second aspect, alone or in combination with the first aspect, the second time window has one or more of a duration or an offset that differs from one or more values indicated in the SMTC received from the wireless network associated with the first RAT.

In a third aspect, alone or in combination with one or more of the first and second aspects, the duration of the second time window covers a union of the one or more SSB spans detected across the one or more cells.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the duration of the second time window covers a union of a subset of the one or more SSB spans that satisfy a threshold.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the offset of the second time window is based at least in part on a system frame boundary prior to a start time of an earliest SSB span among the one or more SSB spans detected across the one or more cells.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, process 700 includes releasing the duration or the offset of the second time window based at least in part on determining that a condition is satisfied, where the condition includes no cells having been detected in the frequency associated with the second RAT for a configured number of searches or measurements, the wireless network associated with the first RAT disabling reselection from the first RAT to the second RAT for the frequency associated with the second RAT, the UE moving to a cell in which an SMTC is not configured for the frequency associated with the second RAT, and/or the like.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, process 700 includes transmitting, to a server on the wireless network associated with the first RAT, information indicating at least a duration and an offset of the second time window in which the one or more cells are measured.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, process 700 includes receiving, from a server on the wireless network associated with the first RAT, information indicating at least a duration and an offset of the second time window in which the one or more cells are measured.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the one or more cells are measured based at least in part on a start time and an end time associated with one or more SSBs that are transmitted by the one or more cells during the one or more SSB spans.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, process 700 includes determining the start time associated with the one or more SSBs based at least in part on a MIB boundary and a half-frame indicator in a PBCH payload transmitted by the one or more cells and determining the end time associated with the one or more SSBs based at least in part on a number of beams and a subcarrier spacing for the one or more cells in the frequency associated with the second RAT.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, process 700 includes determining that the one or more SSB spans include multiple SSB spans with at least one time gap between a first set of SSB spans and a second set of SSB spans, and operating one or more radio components in a low-power state during at least a portion of the second time window that corresponds to the at least one time gap.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the second time window in which the one or more cells are measured is applied for at least two different SIMs.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, process 700 includes performing a search to detect the one or more SSB spans while in an idle state on the wireless network associated with the first RAT.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the UE includes at least a first SIM and a second SIM, and the search to detect the one or more SSB spans is performed for a subscription associated with the first SIM based at least in part on one or more of a service or data activity associated with the second SIM.

In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, the first RAT is an LTE RAT and the second RAT is an NR RAT.

Although Fig. 7 shows example blocks of process 700, in some aspects, process 700 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 7. Additionally, or alternatively, two or more of the blocks of process 700 may be performed in parallel.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software.

As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like.

It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code-it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more. ” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, and/or the like) , and may be used interchangeably with “one or more. ” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has, ” “have, ” “having, ” and/or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.

Claims

A method of wireless communication performed by a user equipment (UE) , comprising:

receiving, from a wireless network associated with a first radio access technology (RAT) , a synchronization signal block (SSB) measurement time configuration (SMTC) for a frequency associated with a second RAT;

detecting one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and

measuring the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.
The method of claim 1, further comprising:

setting the second time window to correspond to the SSB duration indicated in the SMTC, based at least in part on determining that the one or more SSB spans are all within the SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.
The method of claim 1, wherein the second time window has one or more of a duration or an offset that differs from one or more values indicated in the SMTC received from the wireless network associated with the first RAT.
The method of claim 3, wherein the duration of the second time window covers a union of the one or more SSB spans detected across the one or more cells.
The method of claim 3, wherein the duration of the second time window covers a union of a subset of the one or more SSB spans that satisfy a threshold.
The method of claim 3, wherein the offset of the second time window is based at least in part on a system frame boundary prior to a start time of an earliest SSB span among the one or more SSB spans detected across the one or more cells.
The method of claim 3, further comprising:

releasing the duration or the offset of the second time window based at least in part on determining that a condition is satisfied, wherein the condition includes one or more of:

no cells having been detected in the frequency associated with the second RAT for a configured number of searches or measurements,

the wireless network associated with the first RAT disabling reselection from the first RAT to the second RAT for the frequency associated with the second RAT, or

the UE moving to a cell in which an SMTC is not configured for the frequency associated with the second RAT.
The method of claim 1, further comprising:

transmitting, to a server on the wireless network associated with the first RAT, information indicating at least a duration and an offset of the second time window in which the one or more cells are measured.
The method of claim 1, further comprising:

receiving, from a server on the wireless network associated with the first RAT, information indicating at least a duration and an offset of the second time window in which the one or more cells are measured.
The method of claim 1, wherein the one or more cells are measured based at least in part on a start time and an end time associated with one or more SSBs that are transmitted by the one or more cells during the one or more SSB spans.
The method of claim 10, further comprising:

determining the start time associated with the one or more SSBs based at least in part on a master information block boundary and a half-frame indicator in a physical broadcast channel payload transmitted by the one or more cells; and

determining the end time associated with the one or more SSBs based at least in part on a number of beams and a subcarrier spacing for the one or more cells in the frequency associated with the second RAT.
The method of claim 1, further comprising:

determining that the one or more SSB spans include multiple SSB spans with at least one time gap between a first set of SSB spans and a second set of SSB spans; and

operating one or more radio components in a low-power state during at least a portion of the second time window that corresponds to the at least one time gap.
The method of claim 1, wherein the second time window in which the one or more cells are measured is applied for at least two different subscriber identity modules.
The method of claim 1, further comprising:

performing a search to detect the one or more SSB spans while in an idle state on the wireless network associated with the first RAT.
The method of claim 14, wherein the UE includes at least a first subscriber identity module (SIM) and a second SIM, and wherein the search to detect the one or more SSB spans is performed for a subscription associated with the first SIM based at least in part on one or more of a service or data activity associated with the second SIM.
The method of claim 1, wherein the first RAT is a Long Term Evolution RAT and the second RAT is a New Radio RAT.
A user equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:

receive, from a wireless network associated with a first radio access technology (RAT) , a synchronization signal block (SSB) measurement time configuration (SMTC) for a frequency associated with a second RAT;

detect one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and

measure the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.
A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising:

one or more instructions that, when executed by one or more processors of a user equipment (UE) , cause the one or more processors to:

receive, from a wireless network associated with a first radio access technology (RAT) , a synchronization signal block (SSB) measurement time configuration (SMTC) for a frequency associated with a second RAT;

detect one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and

measure the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.
An apparatus for wireless communication, comprising:

means for receiving, from a wireless network associated with a first radio access technology (RAT) , a synchronization signal block (SSB) measurement time configuration (SMTC) for a frequency associated with a second RAT;

means for detecting one or more SSB spans across one or more cells in the frequency associated with the second RAT over a first time window that is based at least in part on a configured periodicity for the frequency associated with the second RAT; and

means for measuring the one or more cells in the frequency associated with the second RAT over a second time window that is determined based at least in part on whether the one or more SSB spans are within an SSB duration indicated in the SMTC received from the wireless network associated with the first RAT.