WO2020199227A1

WO2020199227A1 - Tracking area update (tau) procedure for signaling change in capability dual connectivity (dc) devices

Info

Publication number: WO2020199227A1
Application number: PCT/CN2019/081623
Authority: WO
Inventors: Zhenqing CUI; Haojun WANG; Xuesong Chen; Hong Wei
Original assignee: Qualcomm Incorporated
Priority date: 2019-04-05
Filing date: 2019-04-05
Publication date: 2020-10-08

Abstract

Certain aspects of the present disclosure provide techniques for dynamically signaling a change in dual connectivity mode by a UE, via a tracking area update (TAU) procedure.

Description

TRACKING AREA UPDATE (TAU) PROCEDURE FOR SIGNALING CHANGE IN CAPABILITY DUAL CONNECTIVITY (DC) DEVICES

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for signaling changes to dual connectivity capability via a tracking area update (TAU) procedure.

Description of Related Art

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc. ) . Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system may include a number of base stations (BSs) , which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs) . In an LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB) . In other examples (e.g., in a next generation, a new radio (NR) , or 5G network) , a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs) , edge nodes (ENs) , radio heads (RHs) , smart radio heads (SRHs) , transmission reception points (TRPs) , etc. ) in communication with a number of central units (CUs) (e.g., central nodes (CNs) , access node controllers (ANCs) , etc. ) , where a set of one or more DUs, in communication with a CU, may define an access node (e.g., which may be referred to as a BS, next generation NodeB (gNB or gNodeB) , TRP, etc. ) . A BS or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a BS or DU to a UE) and uplink channels (e.g., for transmissions from a UE to a BS or DU) .

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 (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) . To these ends, NR supports 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 NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved dynamic uplink power control in multi-connectivity mode of a wireless network.

Certain aspects provide a method for wireless communication by a user equipment (UE) . The method generally includes indicating, to at least one of a first network entity of a first radio access technology (RAT) network or a second network entity of a second RAT network, capability to support dual connectivity mode with connection in both the first and second RAT networks and transmitting a tracking area update (TAU) message to at least one of the first or second network entities to dynamically enable or disable the dual connectivity mode.

Certain aspects provide a method for wireless communication by a first network entity of a first radio access technology (RAT) . The method generally includes receiving, from a user equipment (UE) , signaling indicating capability of the UE to support dual connectivity mode with connection in both the first RAT network and a second RAT network and receiving, from the UE, a tracking area update (TAU) message to dynamically enable or disable the dual connectivity mode of the UE.

Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

FIG. 2 is a block diagram conceptually illustrating a design of an example base station and user equipment, in accordance with certain aspects of the present disclosure.

FIG. 3 illustrates example options for dual connectivity, in accordance with certain aspects of the present disclosure.

FIG. 4 illustrates example steps for a UE establishing dual connectivity, in accordance with certain aspects of the present disclosure.

FIG. 5 illustrates example operations for wireless communications by a UE, in accordance with aspects of the present disclosure.

FIG. 6 illustrates example operations for wireless communications by a network entity, in accordance with aspects of the present disclosure.

FIG. 7 illustrates an example call flow diagram for disabling a dual connectivity mode via a TAU, in accordance with aspects of the present disclosure.

FIG. 8 illustrates an example call flow diagram for enabling a dual connectivity mode via a TAU, in accordance with aspects of the present disclosure.

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

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for signaling a change in a dual connectivity mode via a tracking area update (TA) procedure.

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. 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. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

The techniques described herein may be used for various wireless communication technologies, such as 3GPP Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single-carrier frequency division multiple access (SC-FDMA) , time division synchronous code division multiple access (TD-SCDMA) , and other networks. The terms “network” and “system” are often used interchangeably.

A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA) , cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA network may implement a radio technology such as NR (e.g. 5G RA) , Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) . LTE and LTE-A are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) . cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) .

New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF) . NR access (e.g., 5G NR) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond) , massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC) . These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while 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.

Example Wireless Communication Network

FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. The wireless communication network 100 may be an NR system (e.g., a 5G NR network) . Certain aspects of the present disclosure relate to performing dynamic power control on multi-connectivity transmissions.

For example, as shown in FIG. 1, the UE 120 may be communicating with

multiple bases stations

110a and 110b in a multi-connectivity mode (e.g., E-UTRA to NR Dual Connectivity (EN-DC) ) . The UE 120 may have a module for signaling a change in DC connectivity mode via a TAU according to aspects further described herein, for example, with respect to FIGs. 5.

Base stations

110a and 110b may be, for example, an LTE eNB or a 5G/NR gNB and may perform operations shown in FIG. 6.

As illustrated in FIG. 1, the wireless communication network 100 may include a number of base stations (BSs) 110a and 110b and other network entities. A BS may be a station that communicates with user equipment (UEs) . Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a Node B (NB) and/or a NB subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and BS, next generation NodeB (gNB or gNodeB) , access point (AP) , distributed unit (DU) , carrier, or transmission reception point (TRP) may be used interchangeably. 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 BS. In some examples, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

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, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

Wireless communication network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless communication network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt) .

Wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB) ) may be 12 subcarriers (or 180 kHz) . Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz) , respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (e.g., 6 RBs) , and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is the 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, …slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. In some examples, 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. In some examples, 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.

In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs) , and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, 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 communicate directly with one another in addition to communicating with a scheduling entity.

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

FIG. 2 illustrates example components of BS 110 and UE 120 (e.g., in the wireless communication network 100 of FIG. 1) , which may be used to implement aspects of the present disclosure. For example, antennas 252,

processors

266, 258, 264, and/or controller/processor 280 of the UE 120 and/or antennas 234,

processors

220, 230, 238, and/or controller/processor 240 of the BS 110 may be used to perform the various techniques and methods described herein for dynamically controlling uplink transmit power in multi-connectivity mode. For example, as shown in FIG. 4, the controller/processor 280 of the UE 120 has an UL power control module that may be configured for determining whether to multiplex UCI on a PUSCH based at least in part on a reserved transmission power level associated with a cell group, according to aspects described herein.

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

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

On the uplink, at UE 120, a transmit processor 264 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from a data source 262 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 280. The transmit processor 264 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by the demodulators in transceivers 254a-254r (e.g., for SC-FDM, etc. ) , and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 234, processed by the modulators 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 the UE 120. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to the controller/processor 240.

The controllers/

processors

240 and 280 may direct the operation at the BS 110 and the UE 120, respectively. The controller/processor 240 and/or other processors and modules at the BS 110 may perform or direct the execution of processes for the techniques described herein. The

memories

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

Example TAU procedure for signaling change to Dual Connectivity Mode

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for signaling changes to dual connectivity capability via a tracking area update (TAU) procedure. The techniques may be used in systems, for example, that deploy non-standalone 5G-NR.

Non-standalone 5G NR (also known as NSA) generally refers to an early version of 5G NR that relies on other radio access technology (RATs) , such as LTE for support. NSA 5G NR is primarily used for eMBB and is designed to be even more efficient than the preceding LTE.

In 5GNR early time, most operators will deploy the NSA mode in short term, There are many deployment options, with different core network and RAN combinations. For example, FIGs. 3A, 3B, and 3C illustrate various options, generally referred to as

Options

3, 3a, and 3x, respectively.

As illustrated in FIG. 3A, option 3 may involve a master cell group (MCG) split bearer, with an NSA LTE anchor for EPC connection. As illustrated in FIG. 3B, option 3a may involve a single secondary cell group (SCG) bearer, with an NSA LTE anchor for EPC connection. As illustrated in FIG. 3C, option 3x may involve a secondary cell group (SCG) split bearer, with an NSA LTE anchor for EPC connection.

In order to implement these functions, a UE should support dual connectivity, for 4G and NR/5G for the illustrated examples. This type of dual connectivity (DC) is generally referred to as E-UTRA/NR DC (ENDC) . For ENDC devices, UE should connect 4G and 5GNR together, means UE needs to monitor 4G cell and 5G cell at the same times, which consumes a substantial amount of power.

FIG. 4 illustrates various steps a UE may perform or participate in so the UE can support NSA mode, when connected to 4G+5G. First, the UE camps on an LTE cell (eNB) . The UE then sends an ATTACH request indicating support for dual connectivity with NR support (e.g., with DCNR = 1) and indicating support for Dual connectivity of E-UTRA with NR (e.g., ENDC capability = 1) .

The eNB may send a UECapbilityEnquiry (e.g., capability to support NR and ENDC) , to which the UE may report NR and ENDC capability, such as NR band and ENDC combinations. The 5G/gNB may send a 5GNR measurement control via an RRC connection/reconfiguration (for the UE to measure 5G cells) . The UE may send a Measurement report of 5GNR cell. The gNB may send 5GNR DRB configuration with NR band/Freq/DRB/etc. and the UE may then perform acquisition of the 5GNR cell and perform a random access channel (RACH) procedure for the 5G cell.

There are various scenarios, however, where devices that support ENDC (ENDC devices) may want (or need) to disable ENDC or to enable ENDC dynamically for various reasons. Examples of such reasons include power consumption considerations and considerations for multi-SIM devices.

For power consumption consideration, an ENDC device may need to monitor both LTE and 5G cells together, which consumes considerable power compared with monitoring only a single RAT. In order to reduce power consumption, devices can disable ENDC or remove 5G capability.

For Multi-SIM (MSIM) devices (supporting multiple dedicated data subscription or DDSs) , such devices may support ENDC and 4G. In this scenario, for example, only the DDS sub (#1 sub) can support ENDC mode. When the UE switches from this DDS sub, ENDC capability should be changed to 4G. So UE should disable ENDC. For a non-DDS sub (e.g., 4G) , it is changed to ENDC mode from 4G and the UE should be enable ENDC mode.

Aspects of the present disclosure provide techniques for addressing these problems, for example, allowing a UE to disable and enable dual connectivity modes (e.g., ENDC mode) quickly and reasonably, for example, using a tracking area update (TAU) procedure. A tracking area generally refers to a list of cells in a given area. When a UE moves to a new tracking are, with cells that are not included in its list of Tracking Areas with which the UE is registered, the UE may need to send a tracking are update (TAU) so the UE may be located.

FIG. 5 is a flow diagram illustrating example operations 300 for wireless communication, in accordance with certain aspects of the present disclosure. The operations 500 may be performed, for example, by UE (e.g., such as a UE 120 in the wireless communication network 100) .

The operations 500 begin, at 502, by indicating, to at least one of a first network entity of a first radio access technology (RAT) network or a second network entity of a second RAT network, capability to support dual connectivity mode with connection in both the first and second RAT networks. At 504, the UE transmits a tracking area update (TAU) message to at least one of the first or second network entities to dynamically enable or disable the dual connectivity mode.

FIG. 6 is a flow diagram illustrating example operations 600 for wireless communication, in accordance with certain aspects of the present disclosure. The operations 600 may be performed, for example, by a first network entity of a first RAT type (e.g., base station 110 of FIG. 2) such as an LTE eNB.

The operations 600 begin, at 602, by receiving, from a user equipment (UE) , signaling indicating capability of the UE to support dual connectivity mode with connection in both the first RAT network and a second RAT network. At 604, the first network entity receives, from the UE, a tracking area update (TAU) message to dynamically enable or disable the dual connectivity mode of the UE.

FIG. 7 illustrates an example call flow diagram for disabling a dual connectivity mode via a TAU, in accordance with aspects of the present disclosure. As illustrated, when UE needs to disable ENDC, the UE may send a TAU (e.g., with DCNR = 0 and Dual connectivity of E-UTRA with NR capability = 0) . In response, the LTE Network (eNB) that detects the ENDC capability change, eNB may send RRCReconfigurationRequest to delete/release 5G data radio bearers (DRB) .

FIG. 8 illustrates an example call flow diagram for enabling a dual connectivity mode via a TAU, in accordance with aspects of the present disclosure. As illustrated, when the UE decides to enable ENDC, it may send a TAU (e.g., with DCNR = 1 and Dual connectivity of E-UTRA with NR capability = 1) . The eNB may then send a UEcapabilityEnquiry with NR and ENDC. In response, the UE may send a UEcapabilityconfirmation to the eNB (indicating NR and ENDC capability) .

In response to the confirmation, the first RAT (LTE) network may send a measurement control message for the second RAT cells, the UE may measure the second RAT cells, and send measurement report to the first RAT network once it find the cell. The eNB and gNB may then perform a 5g DRB addition procedure. The eNB may also send a Rrcreconfiguraitonrequest to add the gNB DRB. The UE may then perform cell acquisition in the gNB cell and begin performing a RACH procedure.

In some cases, a UE may be configured to automatically send a TAU (indicating a change in DC/capability) , for example, in response to at least one of: a change in power at the UE, a change in data throughput requirement at the UE, or a change if dual SIM card switch.

In some cases, the TAU message may be sent in response to input from a user. The user input may be obtained via at least one of: a manual interface, a graphical user interface, a threshold of UE power level, a threshold of Uplink or Downlink throughput, or a voice command. In some cases, for Dual SIM card devices, one SIM may support dual connectivity mode, while another SIM only support LTE mode. Thus, if a user switches these 2 SIMs, the UE may be triggered to send a TAU to update its capability.

The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells. 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. 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 an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG) , UEs for users in the home, etc. ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. A BS may support one or multiple (e.g., three) cells.

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

A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE) , a cellular phone, 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 computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc. ) , an entertainment device (e.g., a music device, a video device, a satellite radio, etc. ) , a vehicular component or sensor, a smart meter/sensor, 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 machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, 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, which may be narrowband IoT (NB-IoT) devices.

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, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein 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. ” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering. For example, operations 500 shown in FIG. 5 may be performed by one or more of the processors for UE 120 shown in FIG. 2, while operations 600 of FIG. 6 may be performed by or one or more of the processors for base station 110 shown in FIG. 2.

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

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

If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory) , flash memory, ROM (Read Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , EEPROM (Electrically Erasable Programmable Read-Only Memory) , registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

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

Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared (IR) , radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and

disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media) . In addition, for other aspects computer-readable media may comprise transitory computer-readable media (e.g., a signal) . Combinations of the above should also be included within the scope of computer-readable media.

Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein, for example, instructions for performing the operations described herein and illustrated in FIGs. 3 and 4.

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

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

Claims

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

indicating, to at least one of a first network entity of a first radio access technology (RAT) network or a second network entity of a second RAT network, capability to support dual connectivity mode with connection in both the first and second RAT networks; and

transmitting a tracking area update (TAU) message to at least one of the first or second network entities to dynamically enable or disable the dual connectivity mode.
The method of claim 1, wherein:

the first RAT network comprises a long term evolution (LTE) network; and

the second RAT network comprises a new radio (NR) network.
The method of claim 1, wherein:

the TAU message is transmitted to disable the dual connectivity mode.
The method of claim 3, wherein:

the TAU message is sent to the first network entity and indicates a change in UE capability to support dual connectivity in the second RAT network; and

in response to the TAU message, radio bearers for the second RAT network are released.
The method of claim 1, wherein:

the TAU message is transmitted to enable the dual connectivity mode.
The method of claim 5, wherein:

the TAU message is sent to the first network entity and indicates a change in UE capability to support dual connectivity in the second RAT network; and

in response to the TAU message, the first network entity sends a message inquiring about capability of the UE to support dual connectivity.
The method of claim 6, wherein:

the UE sends a response to the message confirming capability to support dual connectivity in the first and second RAT networks;

in response to the confirmation, the first RAT network sends measurement control message for second RAT cells;

the UE measures second RAT cells, and send measurement report to the first RAT network once it find the cell;

the radio bearers for the second RAT network are added; and

after addition of the radio bearers, the UE performs a random access channel (RACH) procedure in the second RAT.
The method of claim 1, wherein the TAU message is sent automatically in response to at least one of:

a change in power at the UE;

a change in data throughput requirement at the UE; or

a change in a dual SIM card switch.
The method of claim 1, wherein the TAU message is sent in response to user input from a user.
The method of claim 9, wherein the user input is obtained via at least one of: a manual interface, a graphical user interface, a threshold of UE power level, a threshold of Uplink or Downlink throughput, or a voice command.
The method of claim 9 wherein, for Dual SIM card devices, which one SIM support dual connectivity mode, another SIM only support LTE mode.
A method of wireless communication by a first network entity of a first radio access technology (RAT) network, comprising:

receiving, from a user equipment (UE) , signaling indicating capability of the UE to support dual connectivity mode with connection in both the first RAT network and a second RAT network;

receiving, from the UE, a tracking area update (TAU) message to dynamically enable or disable the dual connectivity mode of the UE.
The method of claim 12, wherein:

one of the first or second RAT networks comprises a long term evolution (LTE) network; and

the other of the first or second RAT networks comprises a new radio (NR) network.
The method of claim 12, wherein:

the TAU message is transmitted to disable the dual connectivity mode.
The method of claim 14, wherein:

the TAU message indicates a change in UE capability to support dual connectivity in the second RAT network; and

in response to the TAU message, radio bearers for the second RAT network are released.
The method of claim 1, wherein:

the TAU message is transmitted to enable the dual connectivity mode.
The method of claim 16, wherein:

the TAU message indicates a change in UE capability to support dual connectivity in the second RAT network; and

in response to the TAU message, the first network entity sends a message inquiring about capability of the UE to support dual connectivity.
The method of claim 17, wherein:

the UE sends a response to the message confirming capability to support dual connectivity in the first and second RAT networks; and

in response to the confirmation, The first RAT network sends measurement control message for second RAT cells, UE measures second RAT cells, and send measurement report to the first RAT network once it find the suitable cell; and

radio bearers for the second RAT network are added.