Dynamic UE-category switching for enhanced idle mode power savings

Certain aspects of the present disclosure relate to methods and apparatus for dynamic UE-Category switching for enhanced idle mode power savings. A method for wireless communications by a user equipment (UE) is provided. The method generally includes, determining that a cell supports a second UE category, lower than a first UE category; and while in an idle mode: operating in the cell according to the first UE category; and taking action to operate in the cell according to the second UE category based on the determination.

BACKGROUND

Field of the Disclosure

The present disclosure relates generally to communication systems, and more particularly, to methods and apparatus for dynamic UE-Category switching for enhanced idle mode power savings.

Description of Related Art

A wireless communication network may include a number of base stations (BS) that can support communication for a number of user equipments (UEs). A UE may communicate with a 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. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, access point (AP), radio head, TRP (transmit receive point, transmission reception point, etc.), new radio (NR) BS, 5G NB, etc.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices 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 Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) as well as support beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE, NR, and 5G technologies. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

Aspects of the present disclosure relate to methods and apparatus for dynamic UE-Category switching for enhanced idle mode power savings.

Certain aspects of the present disclosure provide a method for wireless communications by a user equipment (UE). The method generally includes determining that a cell supports a second UE category, lower than a first UE category; and while in an idle mode: operating in the cell according to the first UE category; and taking action to operate in the cell according to the second UE category.

Certain aspects of the present disclosure provide an apparatus for wireless communications by a UE. The apparatus generally includes means for determining that a cell supports a second UE category, lower than a first UE category; means for, while in an idle mode, operating in the cell according to the first UE category; and means for, while in the idle mode, taking action to operate in the cell according to the second UE category.

Certain aspects of the present disclosure provide an apparatus for wireless communications by a UE. The apparatus generally includes at least one processor and a memory coupled to the at least one processor. The at least one processor is generally configured to determine that a cell supports a second UE category, lower than a first UE category; and while in an idle mode: operate in the cell according to the first UE category; and take action to operate in the cell according to the second UE category.

Certain aspects of the present disclosure provide a computer readable medium having computer executable code stored thereon for wireless communications by a UE. The computer executable code generally includes code for determining that the cell supports a second UE category, lower than a first UE category; code for, while in an idle mode, operating in the cell according to the first UE category; and code for, while in the idle mode, taking action to operate in the cell according to the second UE category.

Certain aspects of the present disclosure provide a method for wireless communications by a base station (BS). The method generally includes broadcasting information indicating that the BS supports a second UE category, lower than a first UE category; and receiving combined registration information registering a UE as the first UE category and the second UE category.

Certain aspects of the present disclosure provide an apparatus for wireless communications by a BS. The apparatus generally includes means for broadcasting information indicating that the BS supports a second UE category, lower than a first UE category; and means for receiving combined registration information registering a UE as the first UE category and the second UE category.

Certain aspects of the present disclosure provide an apparatus for wireless communications by a BS. The apparatus generally includes at least one processor and a memory coupled to the at least one processor. The at least one processor is generally configured to broadcast information indicating that the BS supports a second UE category, lower than a first UE category; and receive combined registration information registering the UE as the first UE category and the second UE category.

Certain aspects of the present disclosure provide a computer readable medium having computer executable code stored thereon for wireless communications by a BS. The computer executable code generally includes code for broadcasting information indicating that the BS supports a second UE category, lower than a first UE category; and code for receiving combined registration information registering the UE as the first UE category and the second UE category.

Other aspects, features, and aspects of the present disclosure will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary aspects of the present disclosure in conjunction with the accompanying figures. While features of the present disclosure may be discussed relative to certain aspects and figures below, all aspects of the present disclosure can include one or more of the advantageous features discussed herein. In other words, while one or more aspects may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various aspects of the invention disclosure herein. In similar fashion, while exemplary aspects may be discussed below as device, system, or method aspects it should be understood that such exemplary aspects can be implemented in various devices, systems, methods, and computer readable media.

DETAILED DESCRIPTION

As will be described in more detail below, a user equipment (UE) may support various UE-categories (e.g., long term evolution (LTE) UE-categories, 5G UE-categories, etc.). The different UE-categories may define uplink and downlink operating parameters for the UE. Some UE-categories may use less power than other UE-categories. It may desirable for an idle mode UE to operate according to a UE-category that uses less power than a UE-category in the connected mode.

Aspects of the present disclosure provide techniques and apparatus for dynamic UE-Category switching for enhanced idle mode power savings. For example, if the cell supports a lower UE-category, such Cat-M1, the UE may dynamically switch to the lower UE-category when the UE moves to the idle mode or after the UE is in the idle mode for a duration. In some cases, the UE may initiate an out-of-service procedure and then re-register as the lower UE-category. Alternatively, during an initial attach procedure to the cell, the UE may register as both the higher and lower UE-category.

An access point (“AP”) may comprise, be implemented as, or known as NodeB, Radio Network Controller (“RNC”), eNodeB (eNB), Base Station Controller (“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver, Basic Service Set (“BSS”), Extended Service Set (“ESS”), Radio Base Station (“RBS”), Node B (NB), gNB, 5G NB, NR BS, Transmit Receive Point (TRP), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or be known as an access terminal, a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, user equipment (UE), a user station, a wireless node, or some other terminology. In some implementations, an access terminal may comprise a cellular telephone, a smart phone, a cordless telephone, a Session Initiation Protocol (“SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, a Station (“STA”), or some other suitable processing device connected to a wireless modem. Additional examples of access terminals include a computer (e.g., a desktop), a portable communication device, a portable computing device (e.g., a laptop, a personal data assistant, a tablet, a netbook, a smartbook, an ultrabook), wearable device (e.g., smart watch, smart glasses, virtual reality goggles, smart bracelet, smart wristband, smart belt, smart ring, smart jewelry, smart clothing, etc.), medical devices or equipment, healthcare device, biometric sensors/devices, an entertainment device (e.g., music device, video device, satellite radio, gaming device, etc.), a camera, a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a positioning device (e.g., GPS, Beidou, etc.), a drone, a robot/robotic device, or any other suitable device that is configured to communicate via a wireless or wired medium. In some aspects, a node is a wireless node. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered machine-type communication (MTC) or enhanced MTC (eMTC) UEs, which may include remote devices that may communicate with a base station, another remote device, or some other entity. Machine type communications (MTC) may refer to communication involving at least one remote device on at least one end of the communication and may include forms of data communication which involve one or more entities that do not necessarily need human interaction. MTC UEs may include UEs that are capable of MTC communications with MTC servers and/or other MTC devices through Public Land Mobile Networks (PLMN), for example. Examples of MTC devices include sensors, meters, location tags, monitors, drones, robots/robotic devices, etc. MTC UEs, as well as other types of UEs, may be implemented as narrowband Internet-of-Things (NB-IoT) devices.

An Example Wireless Communication System

FIG. 1is a diagram illustrating an architecture for a wireless communication network100in which aspects of the present disclosure may be practiced. For example, the UE120may operate according to a first UE category (e.g., regular UE CAT) in the idle mode. The UE120may determine that the cell (e.g., BS110) supports a second UE category (e.g., UE CAT M1) lower than the first UE category. The UE120may take action to operate in the cell according to the second UE category.

Wireless communication network100may be an LTE network or some other wireless network, such as a 5G or new radio (NR) network. Wireless communication network100may include a number of BSs110and other network entities. ABS is an entity that communicates with user equipments (UEs) and may also be referred to as a NR BS, a Node B (NB), a gNB, a 5G NB, an access point (AP), a transmit receive point (TRP), etc. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in the access network100through various types of backhaul interfaces such as a direct physical connection, a virtual network, or the like using any suitable transport network.

UEs120(e.g.,120a,120b,120c) may be dispersed throughout wireless network100, 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, etc. 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, 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, 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 evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, such as sensors, meters, monitors, location tags, etc., 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 or narrowband IoT (NB-IoT) devices. Some UEs may be considered a Customer Premises Equipment (CPE).

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity.

Base stations are not the only entities that may function as a scheduling entity. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more subordinate entities (e.g., one or more other UEs). In this example, the UE is functioning as a scheduling entity, and other UEs utilize resources scheduled by the UE for wireless communication. A UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may optionally communicate directly with one another in addition to communicating with the scheduling entity.

FIG. 2shows a block diagram of a design of BS110and UE120, which may be one of the BSs and one of the UEs inFIG. 1. BS110may be equipped with T antennas234athrough234t, and UE120may be equipped with R antennas252athrough252r, where in general T>1 and R>1.

Controllers/processors240and280and/or any other component(s) inFIG. 2may direct the operation at base station110and UE120, respectively, to perform techniques presented herein for MSI decoding using an offline or online mode. For example, processor280and/or other processors and modules at UE120, may perform or direct operations of UE120to perform techniques presented herein for dynamic switching of UE-Category. For example, controller/processor280and/or other controllers/processors and modules at UE120may perform or direct operations900shown inFIG. 9. For example, controller/processor240and/or other controllers/processors and modules at base station110may perform or direct operations1000shown inFIG. 10. Memories242and282may store data and program codes for base station110and UE120, respectively. A scheduler246may schedule UEs for data transmission on the downlink and/or uplink.

FIG. 3shows an exemplary frame structure300for FDD in a telecommunications system (e.g., LTE). The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be partitioned into 10 subframes with indices of 0 through 9. Each subframe may include two slots. Each radio frame may thus include 20 slots with indices of 0 through 19. Each slot may include L symbol periods, e.g., seven symbol periods for a normal cyclic prefix (as shown inFIG. 3) or six symbol periods for an extended cyclic prefix. The 2L symbol periods in each subframe may be assigned indices of 0 through 2L−1.

In certain telecommunications (e.g., LTE), a BS may transmit a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) on the downlink in the center of the system bandwidth for each cell supported by the BS. The PSS and SSS may be transmitted in symbol periods 6 and 5, respectively, in subframes 0 and 5 of each radio frame with the normal cyclic prefix, as shown inFIG. 3. The PSS and SSS may be used by UEs for cell search and acquisition. The BS may transmit a cell-specific reference signal (CRS) across the system bandwidth for each cell supported by the BS. The CRS may be transmitted in certain symbol periods of each subframe and may be used by the UEs to perform channel estimation, channel quality measurement, and/or other functions. The BS may also transmit a physical broadcast channel (PBCH) in symbol periods 0 to 3 in slot 1 of certain radio frames. The PBCH may carry some system information. The BS may transmit other system information such as system information blocks (SIBs) on a physical downlink shared channel (PDSCH) in certain subframes. The BS may transmit control information/data on a physical downlink control channel (PDCCH) in the first B symbol periods of a subframe, where B may be configurable for each subframe. The BS may transmit traffic data and/or other data on the PDSCH in the remaining symbol periods of each subframe.

In other systems (e.g., such NR or 5G systems), the BS may transmit these or other signals in these locations or in different locations of the subframe.

FIG. 4shows two exemplary subframe formats410and420with the normal cyclic prefix. The available time frequency resources may be partitioned into resource blocks (RBs). Each RB may cover12subcarriers in one slot and may include a number of resource elements (REs). Each RE may cover one subcarrier in one symbol period and may be used to send one modulation symbol, which may be a real or complex value.

Subframe format410may be used for two antennas. A CRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7 and 11. A reference signal (RS) is a signal that is known a priori by a transmitter and a receiver and may also be referred to as pilot. A CRS is a RS that is specific for a cell, e.g., generated based on a cell identity (ID). InFIG. 4, for a given RE with label Ra, a modulation symbol may be transmitted on that RE from antenna a, and no modulation symbols may be transmitted on that RE from other antennas. Subframe format420may be used with four antennas. A CRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7 and 11 and from antennas 2 and 3 in symbol periods 1 and 8. For both subframe formats410and420, a CRS may be transmitted on evenly spaced subcarriers, which may be determined based on cell ID. CRSs may be transmitted on the same or different subcarriers, depending on their cell IDs. For both subframe formats410and420, REs not used for the CRS may be used to transmit data (e.g., traffic data, control data, and/or other data).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation,” which is publicly available.

The wireless network may support hybrid automatic retransmission request (HARQ) for data transmission on the downlink and uplink. For HARQ, a transmitter (e.g., a BS) may send one or more transmissions of a packet until the packet is decoded correctly by a receiver (e.g., a UE) or some other termination condition is encountered. For synchronous HARQ, all transmissions of the packet may be sent in subframes of a single interlace. For asynchronous HARQ, each transmission of the packet may be sent in any subframe.

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 on various criteria such as received signal strength, received signal quality, pathloss, etc. Received signal quality may be quantified by a signal-to-noise-and-interference ratio (SINR), 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.

Example NR/5G RAN Architecture

While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as new radio (NR) or 5G technologies.

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)). NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. NR may include Enhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra reliable low latency communications (URLLC) service.

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 75 kHz over a 0.1 ms duration. Each radio frame may consist of 50 subframes with a length of 10 ms. Consequently, each subframe may have a length of 0.2 ms. Each subframe may indicate a link direction (i.e., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data. UL and DL subframes for NR may be as described in more detail below with respect toFIGS. 7 and 8.

The RAN may include a central unit (CU) and distributed units (DUs). A NR BS (e.g., gNB, 5G Node B, Node B, transmit receive point (TRP), access point (AP)) may correspond to one or multiple BSs. NR cells can be configured as access cells (ACells) or data only cells (DCells). For example, the RAN (e.g., a central unit or distributed unit) can configure the cells. DCells may be cells used for carrier aggregation or dual connectivity, but not used for initial access, cell selection/reselection, or handover.

FIG. 5illustrates an example logical architecture of a distributed RAN500, according to aspects of the present disclosure. A 5G access node506may include an access node controller (ANC)502. The ANC may be a central unit (CU) of the distributed RAN500. The backhaul interface to the next generation core network (NG-CN)504may terminate at the ANC. The backhaul interface to neighboring next generation access nodes (NG-ANs) may terminate at the ANC. The ANC may include one or more TRPs508(which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, gNB, or some other term). As described above, a TRP may be used interchangeably with “cell.”

The TRPs508may be a distributed unit (DU). The TRPs may be connected to one ANC (ANC502) or more than one ANC (not illustrated). For example, for RAN sharing, radio as a service (RaaS), and service specific AND deployments, the TRP may be connected to more than one ANC. A TRP may include one or more antenna ports. The TRPs may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE. According to certain aspects, a BS may include a central unit (CU) (e.g., ANC502) and/or one or more distributed units (e.g., one or more TRPs508).

The architecture may enable cooperation between and among TRPs508. For example, cooperation may be pre-set within a TRP and/or across TRPs via the ANC502. According to aspects, no inter-TRP interface may be needed/present.

According to aspects, a dynamic configuration of split logical functions may be present within the architecture500. The PDCP, RLC, MAC protocol may be adaptively placed at the ANC or TRP.

FIG. 6illustrates an example physical architecture of a distributed RAN600, according to aspects of the present disclosure. A centralized core network unit (C-CU)602may host core network functions. The C-CU may be centrally deployed. C-CU functionality may be offloaded (e.g., to advanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU)604may host one or more ANC functions. Optionally, the C-RU may host core network functions locally. The C-RU may have distributed deployment. The C-RU may be closer to the network edge.

A distributed unit (DU)606may host one or more TRPs. The DU may be located at edges of the network with radio frequency (RF) functionality.

FIG. 7is a diagram700showing an example of a DL-centric subframe. The DL-centric subframe may include a control portion702. The control portion702may exist in the initial or beginning portion of the DL-centric subframe. The control portion702may include various scheduling information and/or control information corresponding to various portions of the DL-centric subframe. In some configurations, the control portion702may be a physical DL control channel (PDCCH), as indicated inFIG. 7. The DL-centric subframe may also include a DL data portion704. The DL data portion704may sometimes be referred to as the payload of the DL-centric subframe. The DL data portion704may include the communication resources utilized to communicate DL data from the scheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE). In some configurations, the DL data portion704may be a physical DL shared channel (PDSCH).

The DL-centric subframe may also include a common UL portion706. The common UL portion706may sometimes be referred to as an UL burst, a common UL burst, and/or various other suitable terms. The common UL portion706may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the common UL portion706may include feedback information corresponding to the control portion702. Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information. The common UL portion706may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information. As illustrated inFIG. 7, the end of the DL data portion704may be separated in time from the beginning of the common UL portion706. This time separation may sometimes be referred to as a gap, a guard period, a guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the subordinate entity (e.g., UE)) to UL communication (e.g., transmission by the subordinate entity (e.g., UE)). One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

FIG. 8is a diagram800showing an example of an UL-centric subframe. The UL-centric subframe may include a control portion802. The control portion802may exist in the initial or beginning portion of the UL-centric subframe. The control portion802inFIG. 8may be similar to the control portion802described above with reference toFIG. 8. The UL-centric subframe may also include an UL data portion804. The UL data portion804may sometimes be referred to as the payload of the UL-centric subframe. The UL portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS). In some configurations, the control portion802may be a physical downlink control channel (PDCCH).

As illustrated inFIG. 8, the end of the control portion802may be separated in time from the beginning of the UL data portion804. This time separation may sometimes be referred to as a gap, guard period, guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the scheduling entity) to UL communication (e.g., transmission by the scheduling entity). The UL-centric subframe may also include a common UL portion806. The common UL portion806inFIG. 8may be similar to the common UL portion706described above with reference toFIG. 7. The common UL portion806may additional or alternative include information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

In one example, a frame may include both UL centric subframes and DL centric subframes. In this example, the ratio of UL centric subframes to DL subframes in a frame may be dynamically adjusted based on the amount of UL data and the amount of DL data that are transmitted. For example, if there is more UL data, then the ratio of UL centric subframes to DL subframes may be increased. Conversely, if there is more DL data, then the ratio of UL centric subframes to DL subframes may be decreased.

Example Methods and Apparatus for Dynamic UE-Category Switching for Enhanced Idle Mode Power Savings

A user equipment (UE) or a modem may perform idle mode activities. The UE or modem may be an Internet-of-Things (IoT) device, a narrowband IoT (NB-IoT), or other wireless communications device. The device may communication using long term evolution (LTE) as the access stratum or according to different access stratum, for example, such as new radio (NR) or 5G. The idle mode activities performed by the device may be mandated by a wireless communication standard (e.g., such as the IEEE LTE standards). The idle mode activities may be different based on the UE-Category (CAT) of the device, or the UE Category of which the device is registered with the network.

The UE Category may define uplink and downlink capability of the UE. In one example, the capabilities associated with the UE Category may be as defined in TS 36.306 of the 3GPP wireless standards (e.g., Table 4.1-1 for downlink and Table 4.1-2 for the uplink). Other UE Categories may be defined by different wireless standards. For example, LTE Release-12 introduces Cat 0 which may be used for IoT, NB-IoT and/or enhanced machine type communication (eMTC) devices. As another example, LTE Release-13 introduces UE Cat-M1. UE Cat-M1 may have a DL peak rate 1 Mbps, and uplink peak rate 1 Mbps, may operate according to half duplex (HD) or full duplex (FD), may use 1.4 MHz bandwidth, and a maximum transmit power of 20 dBm or 23 dBm. These UE categories are merely exemplary, other UE categories may be defined, and the techniques of this disclosure may be applied for wireless device operating according to and/or supporting various different UE categories (e.g., LTE-M, EC-GSM-IoT (enhanced or extended coverage GSM IoT), LPWA (low power wide area), etc.).

In some cases, activities (operations) performed according to low UE categories may use less power than activities performed according to higher UE categories. Idle mode activities may drain power, even for lower UE categories (e.g., CAT 1) mobile devices.

Accordingly, techniques and apparatus for reducing power consumed by idle mode UEs are desirable—while still remaining compliant to the 3GPP specifications.

Aspects of the present disclosure relate to methods and apparatus for dynamic UE-Category switching for enhanced idle mode power savings. For example, UEs moving to the idle mode may switch to (e.g., drop down to) a lower UE-Category (e.g., such Cat-M1), while UEs moving to the connected mode may switch to a higher UE-Category (e.g., referred to as a regular UE Category, for example, which may include UE categories 1 and higher defined in the wireless standards).

In some cases, enhanced discontinuous reception (eDRX) and/or power saving mode (PSM) can be used by UEs that support lower UE-categories. eDRX and PSM are features that enable very long battery lifetimes, such as 10 years or more. eDRX may include use of extended DRX cycles that provide UEs with longer sleeping periods between reading paging or control channels. In PSI, the UE can save power when there is no frequent need to communicate with the device.

FIG. 9is a flow diagram illustrating operations900that may be performed, for example, by a UE (e.g., UE120, which may be an MTC or eMTC device, IoT device, NB-IoT device, or other low cost device) for dynamic switching of the UE-Category, in accordance with certain aspects of the present disclosure. The operations900may begin, at902, the UE determines (e.g., by monitoring broadcast information from the cell) that a cell supports a second UE category (e.g., Cat-M1), lower than a first UE category. At904, while in an idle mode (e.g., after a threshold duration in the idle mode), the UE operates in the cell according to the first UE category (e.g., a regular UE-Category, such Cat 1 or higher). At906, while in the idle mode, the UE takes action to operate in the cell according to the second UE category.

As described in more detail below, the UE may initiate a switch and then register with the cell as the second UE category. For example, the UE may perform an out-of-service (00S) procedure with the cell and register with the cell as the second UE category. Alternatively, the UE may register with the cell, during an initial attach, as both the first UE category and the second UE category. The UE may dynamically provide an indication of a currently selected UE category. The UE can then register as the first UE category while entering the connected mode (e.g., while attempting to connect to the cell which may occur after receiving paging from the cell) or as the second UE category when moving to the idle mode.

FIG. 10is a flow diagram illustrating operations1000that may be performed, for example, by a BS (e.g., BS110) for dynamic switching of UE-category, in accordance with certain aspects of the present disclosure. The operations1000may begin, at1002, by broadcasting information indicating that the BS supports a second UE category (e.g., UE Cat-M1), lower than a first UE category. At1004, the BS receives combined registration information registering a UE as the first UE category and the second UE category. The BS may receive the combined registration information during an initial attachment procedure. The BS may receive an indication of a currently selected UE category. The indication may be provided dynamically by the UE. For example, the BS may receive registration information registering the UE as the first UE category along with a connection setup message from the UE and/or the BS may receive registration information registering the UE as the second UE category when the UE moves to the idle mode.

Example Dynamic UE-Category Switching and Re-registration

According to certain aspects, the UE may perform dynamic switching and re-registering with the cell as a different UE-Category.

FIG. 11is a call flow diagram1100for dynamically switching UE-Category, in accordance with certain aspects of the present disclosure. In aspects, the UE1102may support a low UE-category, such as Cat-M1 mode of operation. The UE1102may operate according to a first UE-Category, which may be a regular UE-CAT (e.g., CAT 1 or beyond). For example, at1110, the UE1102may register with BS1104as the regular UE-CAT.

At1106, the UE may receive broadcast information from the BS1104and, at1108, determine that the BS1104supports the low UE-category (e.g., CAT-M1) based on the broadcast information. For example, UE1102may monitor the network for broadcast information (e.g., monitor the physical broadcast channel (PBCH)). At1106, the UE1102may receive the broadcast information (e.g., master information block (MIB) and system information blocks (SIBs)) from the BS1104. Based on the broadcast information, the UE1102may determine, at1108, that the BS1104supports a lower UE-Category, such as Cat-M1. For example, the schedulingInfoSIB1-BR element in the MIB may indicate that the cell supports Cat-M1.

Although shown inFIG. 11before registering as the UE-CAT at1100, the receipt of the broadcast information and the determination at steps1106and1108could occur at other times, such as after the registration at1110or after the UE enters the idle mode at1112.

At1112, the UE may enter an idle mode. At1114, the idle mode UE1102may dynamically switch to a lower UE-CAT in order to enhance power savings during the idle mode (e.g., based on the determination that the BS1104supports CAT M1). In some cases, the idle mode UE1102may wait for a pre-configured duration (e.g., a threshold duration) in the idle mode before switching. For example, although not shown inFIG. 11, the UE could initiate a timer upon entering the idle mode and switch the UE category at expiry of the timer.

According to certain aspects, if the network (e.g., cell, BS1104) supports the lower UE-category, such as Cat-M1 mode of operation, at1114, the UE1102may switch UE category and, at1116, re-register as the lower UE-Category with the network. Based on the registration for the lower UE-category, the network may know that the UE pages are to be repeated and the paging cycle extended (e.g., using eDRX).

When the UE1102receives, at1118, a page from BS1104that is directed to the UE (e.g., such as a mobile terminated (MT) call) or when the UE1102initiates a call (e.g., a mobile originated (MO) call), the UE1102may again switch UE category at1120(e.g., back to the original regular UE category or a different UE category). For example, at1122, the UE1102may re-register to the network as the higher UE-Category and then move to the connected state (e.g., during the call setup).

Operating according to the lower UE-category, such as Cat-M1, may result in large idle mode power savings for the UE.

Example Dynamic UE-Category Switching Using Multiple UE-Category Registration

According to certain aspects, the UE may be register with multiple UE-categories (e.g., a regular UE-CAT and Cat-M1) to enable dynamic UE-category switching.

FIG. 12is a call flow diagram1200for dynamically switching UE-Category, in accordance with certain aspects of the present disclosure. As shown inFIG. 12, at1206, the UE1202can register with the BS1204as multiple UE-categories. For example, during an initial attachment procedure with the cell, the UE1202may send combined registration information registering the UE1202as a regular CAT (e.g., CAT 1 or higher) and low UE category, such as Cat-M1. Along with the combined registration information, at1206, UE1202may also indicate the chosen category to be used henceforth (e.g., the currently selected UE category). After the combined registration, the UE1202can dynamically switch between the registered UE-categories. For example, at1208, the UE1202may receive paging from the BS1204and, at1210attempt to connect to the network and move to the connected state. During the connection attempt at1210, the UE1202may register as the regular UE-category, for example by sending a new message (e.g., an indication or registration information) to the network. For example, the new message may be sent along with a connection setup message at1210. While moving back from the connected state to the idle mode (or after entering the idle mode, e.g., shortly after entering the idle mode) at1212, the UE may register itself as the Cat-M1 at1214.

As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase, for example, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, for example the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. As used herein, reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” For example, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form. Unless specifically stated otherwise, the term “some” refers to one or more. As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, 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). As used herein, including in the claims, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

In some cases, rather than actually transmitting a frame, a device may have an interface to output a frame for transmission. For example, a processor may output a frame, via a bus interface, to an RF front end for transmission. Similarly, rather than actually receiving a frame, a device may have an interface to obtain a frame received from another device. For example, a processor may obtain (or receive) a frame, via a bus interface, from an RF front end for transmission.

For example, means for determining, means for performing, means for operating, means for transmitting, means for receiving, means for sending, means for signaling, means for selecting, means for determining, means for identifying, means for registering, means for attempting, means for broadcasting, means for initiating, means for taking action, and/or means for monitoring may include one or more processors or other elements, such as the transmit processor264, the controller/processor280, the receive processor258, and/or antenna(s)252of the user equipment120illustrated inFIG. 2, and/or the transmit processor220, the controller/processor240, and/or antenna(s)234of the base station110illustrated inFIG. 2.