WO2021232181A1

WO2021232181A1 - Methods and apparatus for improving handover

Info

Publication number: WO2021232181A1
Application number: PCT/CN2020/090774
Authority: WO
Inventors: Guojing LIU; Dongsheng Wang; Chaofeng HUI; Xiaomeng Lu; Xuesong Chen; Fojian ZHANG; Wei Dong; Dunfa SHI
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-18
Filing date: 2020-05-18
Publication date: 2021-11-25

Abstract

Aspects of the present disclosure include methods, apparatuses, and computer readable media for establishing a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode, receiving one or more reference signals from the first cell, determining a channel quality associated with the second cell based on the one or more reference signals, determining whether a channel quality is lower than a threshold, determining whether a handover condition is satisfied in response to the channel quality being lower than the threshold and establishing a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.

Description

METHODS AND APPARATUS FOR IMPROVING HANDOVER

BACKGROUND

Aspects of the present disclosure relate generally to wireless communications, and more particularly, to apparatuses and methods for improving handover.

Wireless communication networks are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.

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. For example, a fifth generation (5G) wireless communications technology (which may be referred to as new radio (NR) ) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology may include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which may allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, further improvements in NR communications technology and beyond may be desired.

In a wireless communication network, a first base station (BS) of a first radio access technology in a first cell may attempt to perform a handover process associated with a user equipment (UE) . The handover process may cause the UE to connect to a second BS of a second radio access technology in a second cell. However, the handover process may cause the UE to disconnect from a cell having a higher bandwidth and connect to the second cell having a lower bandwidth. Therefore, improvements in the handover process may be desirable.

SUMMARY

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

Aspects of the present disclosure include methods by a user equipment (UE) for establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode, receive one or more reference signals from the first cell, determine a channel quality associated with the second cell based on the one or more reference signals, determine whether a channel quality is lower than a threshold, determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold, and establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.

Any of the methods above, further comprising, maintaining the first connection to the first cell without establishing the second connection to the second cell in response to the channel quality being higher than or equal to the threshold.

Any of the methods above, further comprising, maintaining the first connection to the first cell without establishing the second connection to the second cell in response to the handover condition being not satisfied.

Any of the methods above, wherein the channel quality comprises a reference signal received power (RSRP) or a signal to noise ratio (SNR) .

Any of the methods above, wherein determining whether the channel quality is lower than the threshold comprises determining whether the RSRP is less than -105 decibel milliwatts.

Any of the methods above, wherein determining whether the channel quality is lower than the threshold comprises determining whether the SNR is less than 10 decibel.

Any of the methods above, wherein the handover condition is satisfied is satisfied when

RSCP _{nonservingcell} + Offset _{nonservingcell} –hysteresis > threshold _{nonservingcell} during a time interval.

Any of the methods above, wherein establishing the second connection to the second cell comprises establishing the second connection to the second cell while maintaining the first connection to the first cell.

Other aspects of the present disclosure include a user equipment (UE) having a memory comprising instructions, a transceiver, and one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode, receive one or more reference signals from the first cell, determine a channel quality associated with the second cell based on the one or more reference signals, determine whether a channel quality is lower than a threshold, determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold, and establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.

An aspect of the present disclosure includes a user equipment (UE) including means for establishing a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode, means for receiving one or more reference signals from the first cell, means for determining a channel quality associated with the second cell based on the one or more reference signals, means for determining whether a channel quality is lower than a threshold, means for determining whether a handover condition is satisfied in response to the channel quality being lower than the threshold, and means for establishing a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.

Some aspects of the present disclosure include non-transitory computer readable media having instructions stored therein that, when executed by one or more processors of a user equipment (UE) , cause the one or more processors to establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode, receive one or more reference signals from the first cell, determine a channel quality associated with the second cell based on the one or more reference signals, determine a channel quality associated with the second cell based on the one or more reference signals, determine whether a channel quality is lower than a threshold, determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold, and establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.

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 annexed 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, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which:

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network;

FIG. 2 is a schematic diagram of an example of a user equipment;

FIG. 3 is a schematic diagram of an example of a base station;

Fig. 4 illustrates an example of an environment for a first cell of a first RAT to determine the handover process associated with a UE to a second cell of a second RAT according to aspects of the present disclosure;

Fig. 5 illustrates an example of a process for performing handover according to aspects of the present disclosure; and

Fig. 6 illustrates an example of a method for performing handover by the UE according to aspects of the present disclosure.

An appendix, the contents of which are incorporated in their entireties, is attached.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

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

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that may be used to store computer executable code in the form of instructions or data structures that may be accessed by a computer.

In some implementations, a UE may operate in dual connectivity mode. The UE may connect to a 4G Long-Term Evolution anchor cell and a 5G New Radio secondary cell. When a specific handover condition is met, the anchor cell may attempt to handover the UE to a cell with a different technology (e.g., 2G or 3G) . However, this handover process may interrupt the 5G connection of the UE.

In one aspect of the present disclosure, the UE may first perform a channel quality assessment by comparing a channel quality to a threshold. If the channel quality is lower than the threshold, the UE may proceed to determine whether the handover condition is met. If the channel quality is higher than or equal to the threshold, the UE may “camp” on the anchor cell and/or the secondary cell without determining whether the handover condition is met. The UE may continue to connect to the 4G and/or 5G cell.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes at least one base station (BS) 105, UEs 110, an Evolved Packet Core (EPC) 160, and a 5G Core (5GC) 190. The BS 105 may include macro cells (high power cellular base station) and/or small cells (low power cellular base station) . The macro cells include base stations. The small cells include femtocells, picocells, and microcells. In one implementation, the UE 110 may include a communication component 222 configured to communicate with the BS 105 via a cellular network, a Wi-Fi network, or other wireless and wired networks. In some implementations, the UE 110 may include a determination component 224 that determines the channel quality and/or the handover condition. In some implementations, the communication component 222 and/or the determination component 224 may be implemented using hardware, software, or a combination of hardware and software. In some implementations, the BS 105 may include a communication component 322 configured to communicate with the UE 110. In some implementations, the communication component 322 may be implemented using hardware, software, or a combination of hardware and software.

ABS 105 configured for 4G Long-Term Evolution (LTE) (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through backhaul links interfaces 132 (e.g., S1, X2, Internet Protocol (IP) , or flex interfaces) . A BS 105 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through backhaul links interfaces 134 (e.g., S1, X2, Internet Protocol (IP) , or flex interface) . In addition to other functions, the BS 105 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The BS 105 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over the backhaul links interfaces 134. The backhaul links 132, 134 may be wired or wireless.

The BS 105 may wirelessly communicate with the UEs 110. Each of the BS 105 may provide communication coverage for a respective geographic coverage area 130. There may be overlapping geographic coverage areas 130. For example, the small cell 105' may have a coverage area 130' that overlaps the coverage area 130 of one or more macro BS 105. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the BS 105 and the UEs 110 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 110 to a BS 105 and/or downlink (DL) (also referred to as forward link) transmissions from a BS 105 to a UE 110. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The BS 105 /UEs 110 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Y _x MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 110 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 105' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 105' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 105', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

ABS 105, whether a small cell 105' or a large cell (e.g., macro base station) , may include an eNB, gNodeB (gNB) , or other type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 110. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the radio frequency (RF) in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 110 to compensate for the path loss and short range.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 110 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a packet switched (PS) Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the BS 105 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The 5GC 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 110 and the 5GC 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The BS 105 may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, an access point, an access node, a radio transceiver, a NodeB, eNodeB (eNB) , gNB, Home NodeB, a Home eNodeB, a relay, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The BS 105 provides an access point to the EPC 160 or 5GC 190 for a UE 110. Examples of UEs 110 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 110 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 110 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring to FIG. 2, one example of an implementation of the UE 110 may include a modem 220 having the communication component 222 and/or the determination component 224. The communication component 222 and/or the modem 220 of the UE 110 may be configured to communicate with the BS 105 via a cellular network, a Wi-Fi network, or other wireless and wired networks. In some implementations, the UE 110 may include a determination component 224 that determines the channel quality and/or the handover condition.

In some implementations, the UE 110 may include a variety of components, including components such as one or more processors 212 and memory 216 and transceiver 202 in communication via one or more buses 244, which may operate in conjunction with the modem 220 and the communication component 222 to enable one or more of the functions described herein related to communicating with the BS 105. Further, the one or more processors 212, modem 220, memory 216, transceiver 202, RF front end 288 and one or more antennas 265, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. The one or more antennas 265 may include one or more antennas, antenna elements and/or antenna arrays.

In an aspect, the one or more processors 212 may include the modem 220 that uses one or more modem processors. The various functions related to the communication component 222 and/or the determination component 224 may be included in the modem 220 and/or processors 212 and, in an aspect, may be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors 212 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiving device processor, or a transceiver processor associated with transceiver 202. Additionally, the modem 220 may configure the UE 110 along with the processors 212. In other aspects, some of the features of the one or more processors 212 and/or the modem 220 associated with the communication component 222 may be performed by transceiver 202.

The memory 216 may be configured to store data used and/or local versions of application 275. Also, the memory 216 may be configured to store data used herein and/or local versions of the communication component 222 and/or the determination component 224, and/or one or more of the subcomponents being executed by at least one processor 212. Memory 216 may include any type of computer-readable medium usable by a computer or at least one processor 212, such as random access memory (RAM) , read only memory (ROM) , tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory 216 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the communication component 222 and/or the determination component 224, and/or one or more of the subcomponents, and/or data associated therewith, when UE 110 is operating at least one processor 212 to execute the communication component 222 and/or the determination component 224, and/or one or more of the subcomponents.

Transceiver 202 may include at least one receiver 206 and at least one transmitter 208. Receiver 206 may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . Receiver 206 may be, for example, a RF receiving device. In an aspect, the receiver 206 may receive signals transmitted by at least one BS 105. Transmitter 208 may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . A suitable example of transmitter 208 may including, but is not limited to, an RF transmitter.

Moreover, in an aspect, UE 110 may include RF front end 288, which may operate in communication with one or more antennas 265 and transceiver 202 for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one BS 105 or wireless transmissions transmitted by UE 110. RF front end 288 may be coupled with one or more antennas 265 and may include one or more low-noise amplifiers (LNAs) 290, one or more switches 292, one or more power amplifiers (PAs) 298, and one or more filters 296 for transmitting and receiving RF signals.

In an aspect, LNA 290 may amplify a received signal at a desired output level. In an aspect, each LNA 290 may have a specified minimum and maximum gain values. In an aspect, RF front end 288 may use one or more switches 292 to select a particular LNA 290 and the specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA (s) 298 may be used by RF front end 288 to amplify a signal for an RF output at a desired output power level. In an aspect, each PA 298 may have specified minimum and maximum gain values. In an aspect, RF front end 288 may use one or more switches 292 to select a particular PA 298 and the specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters 296 may be used by RF front end 288 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter 296 may be used to filter an output from a respective PA 298 to produce an output signal for transmission. In an aspect, each filter 296 may be coupled with a specific LNA 290 and/or PA 298. In an aspect, RF front end 288 may use one or more switches 292 to select a transmit or receive path using a specified filter 296, LNA 290, and/or PA 298, based on a configuration as specified by transceiver 202 and/or processor 212.

As such, transceiver 202 may be configured to transmit and receive wireless signals through one or more antennas 265 via RF front end 288. In an aspect, transceiver may be tuned to operate at specified frequencies such that UE 110 may communicate with, for example, one or more BS 105 or one or more cells associated with one or more BS 105. In an aspect, for example, the modem 220 may configure transceiver 202 to operate at a specified frequency and power level based on the UE configuration of the UE 110 and the communication protocol used by the modem 220.

In an aspect, the modem 220 may be a multiband-multimode modem, which may process digital data and communicate with transceiver 202 such that the digital data is sent and received using transceiver 202. In an aspect, the modem 220 may be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem 220 may be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem 220 may control one or more components of UE 110 (e.g., RF front end 288, transceiver 202) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration may be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration may be based on UE configuration information associated with UE 110 as provided by the network.

Referring to FIG. 3, one example of an implementation of the BS 105 may include a modem 320 having the communication component 322. The communication component 322 and/or the modem 320 the BS 105 may be configured to communicate with the UE 110 via a cellular network, a Wi-Fi network, or other wireless and wired networks.

In some implementations, the BS 105 may include a variety of components, including components such as one or more processors 312 and memory 316 and transceiver 302 in communication via one or more buses 344, which may operate in conjunction with the modem 320 and the communication component 322 to enable one or more of the functions described herein related to communicating with the UE 110. Further, the one or more processors 312, modem 320, memory 316, transceiver 302, RF front end 388 and one or more antennas 365, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies.

In an aspect, the one or more processors 312 may include the modem 320 that uses one or more modem processors. The various functions related to the communication component 322 may be included in the modem 320 and/or processors 312 and, in an aspect, may be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors 312 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiving device processor, or a transceiver processor associated with transceiver 302. Additionally, the modem 320 may configure the BS 105 and processors 312. In other aspects, some of the features of the one or more processors 312 and/or the modem 320 associated with the communication component 322 may be performed by transceiver 302.

The memory 316 may be configured to store data used herein and/or local versions of applications 375. Also, the memory 316 may be configured to store data used herein and/or local versions of the communication component 322, and/or one or more of the subcomponents being executed by at least one processor 312. Memory 316 may include any type of computer-readable medium usable by a computer or at least one processor 312, such as random access memory (RAM) , read only memory (ROM) , tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory 316 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining the communication component 322, and/or one or more of the subcomponents, and/or data associated therewith, when the BS 105 is operating at least one processor 312 to execute the communication component 322, and/or one or more of the subcomponents.

Transceiver 302 may include at least one receiver 306 and at least one transmitter 308. The at least one receiver 306 may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . The receiver 306 may be, for example, a RF receiving device. In an aspect, receiver 306 may receive signals transmitted by the UE 110. Transmitter 308 may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . A suitable example of transmitter 308 may including, but is not limited to, an RF transmitter.

Moreover, in an aspect, the BS 105 may include RF front end 388, which may operate in communication with one or more antennas 365 and transceiver 302 for receiving and transmitting radio transmissions, for example, wireless communications transmitted by other BS 105 or wireless transmissions transmitted by UE 110. RF front end 388 may be coupled with one or more antennas 365 and may include one or more low-noise amplifiers (LNAs) 390, one or more switches 392, one or more power amplifiers (PAs) 398, and one or more filters 396 for transmitting and receiving RF signals.

In an aspect, LNA 390 may amplify a received signal at a desired output level. In an aspect, each LNA 390 may have a specified minimum and maximum gain values. In an aspect, RF front end 388 may use one or more switches 392 to select a particular LNA 390 and the specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA (s) 398 may be used by RF front end 388 to amplify a signal for an RF output at a desired output power level. In an aspect, each PA 398 may have specified minimum and maximum gain values. In an aspect, RF front end 388 may use one or more switches 392 to select a particular PA 398 and the specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters 396 may be used by RF front end 388 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter 396 may be used to filter an output from a respective PA 398 to produce an output signal for transmission. In an aspect, each filter 396 may be coupled with a specific LNA 390 and/or PA 398. In an aspect, RF front end 388 may use one or more switches 392 to select a transmit or receive path using a specified filter 396, LNA 390, and/or PA 398, based on a configuration as specified by transceiver 302 and/or processor 312.

As such, transceiver 302 may be configured to transmit and receive wireless signals through one or more antennas 365 via RF front end 388. In an aspect, transceiver may be tuned to operate at specified frequencies such that BS 105 may communicate with, for example, the UE 110 or one or more cells associated with one or more BS 105. In an aspect, for example, the modem 320 may configure transceiver 302 to operate at a specified frequency and power level based on the base station configuration of the BS 105 and the communication protocol used by the modem 320.

In an aspect, the modem 320 may be a multiband-multimode modem, which may process digital data and communicate with transceiver 302 such that the digital data is sent and received using transceiver 302. In an aspect, the modem 320 may be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem 320 may be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem 320 may control one or more components of the BS 105 (e.g., RF front end 388, transceiver 302) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration may be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration may be based on base station configuration associated with the BS 105.

Fig. 4 illustrates an example of an environment for a first cell of a first RAT to determine the handover process associated with a UE to a second cell of a second RAT. In some implementations, an environment 400 may include a first BS 105a associated with a first cell 410a. The first BS 105b may include a first coverage area 130a. The first cell 410a may operate using a first technology (e.g., NR, LTE, GSM, UTRA, Wi-Fi, etc. ) . The environment 400 may include a second BS 105b associated with a second cell 410b. The second BS 105b may include a second coverage area 130b. The second cell 410b may operate using a second technology different than the first technology. For example, the second technology may include NR, LTE, GSM, UTRA, Wi-Fi, etc. The environment 400 may include the UE 110 within the first coverage area 130a and the second coverage area 130b. The UE 110 may communicate with the first BS 105a via the first communication links 120a and with the second BS 105b via the second communication links 120b. The first cell 410a may communicate with the second cell 410b via the backhaul links 132, 134.

In one implementation, the first cell 410a may include the first BS 105a. Alternatively, the first cell 410a may include the first BS 105a and one or more additional base stations. The second cell 410b may include the second BS 105b. Alternatively, the second cell 410b may include the second BS 105b and one or more additional base stations.

During operation, in some implementations, the UE 110 may be wirelessly connected to the first BS 105a of the first cell 410a. The first cell 410a may be the master cell or the master cell group for the UE 110. When the UE 110 is within the second coverage area 130b, the first cell 410a and/or the UE 110 may attempt to perform a handover process. The handover process may cause the UE 110 to establish a connection with the second cell 410b. In one example, after the handover process, the UE 110 may connect to the second cell 410a. In another instance, after the handover process, the UE 110 may connect to the first cell 410a (e.g., the master cell or the master cell group) and to the second cell 410b (e.g., the secondary cell or the secondary cell group) .

In some implementations, prior to initiating the handover process, the UE 110 may initialize a channel quality evaluation of the first cell 410a. In an aspect of the present disclosure, the first cell 410a may transmit one or more reference signals (RSs) to the UE 110. The UE 110 may receive the one or more reference signals. The UE 110 may determine the channel quality using at least one of a reference signal received power (RSRP) , a reference signal received quality (RSRQ) , a reference signal strength indication, a reference signal strength indication (RSSI) , a signal to noise ratio (SNR) , or a signal to interference plus noise ratio (SINR) . In an example, the UE 110 may measure the RSRP based on the average power level of power levels of the one or more reference signals. In another example, the UE 110 may measure the RSSI based on the total power of the one or more reference signals. In some examples, the UE 110 may measure the RSRQ based on the RSRP and the RSSI. In certain examples, the UE 110 may measure the SINR based on the received powers of the signal, the noise, and the interference. Other measurements may also be used to measure the channel quality between the UE 110 and the first cell 410a.

In certain aspects of the present disclosure, the UE 110 may compare at least one of the RSRP, RSRQ, RSSI, SNR, and/or SINR to one or more threshold values. The first BS 105a may transmit one or more threshold values to the UE 110. The one or more threshold values may be stored in the memory 216 of the UE 110. The UE 110 may compare the measured channel quality to a corresponding threshold. Depending on the comparison, the UE 110 may “camp” on the first cell 410a or to evaluate a handover condition to another cell, e.g., the second cell 410b. In one aspect, the UE 110 may compare the RSRP with a threshold RSRP (RSRP _Thresh) . If the RSRP is greater than or equal to the RSRP _Thresh (e.g., RSRP ≥ -105 decibel milliwatt (dBm) ) , the UE 110 may determine to remain in the first cell 410a. Alternatively or additionally, the UE 110 may compare the SNR with a threshold SNR (SNR _Thresh) . If the SNR is greater than or equal to the SNR _Thresh (e.g., SNR ≥ 10 decibel (dB) ) , the UE 110 may determine to remain in the first cell 410a.

In some aspects, if the RSRP is less than the RSRP _Thresh (e.g., RSRP < -105decibel milliwatt (dBm) ) , the UE 110 may determine to evaluate a handover condition. Alternatively or additionally, the SNR is less than the SNR _Thresh (e.g., SNR < 10 decibel (dB) ) , the UE 110 may determine to evaluate the handover condition.

In certain aspects of the present disclosure, in response to determining to evaluate the handover condition, the UE 110 may measure the quality of the connection to the second BS 105b of the second cell 410b. For example, the second BS 105b of the second cell 410b may transmit one or more signals (e.g., reference signals) to the UE 110. Based on the one or more signals, the UE 110 may measure at least one of the signal strength (RSCP _{nonservingcell}) and/or the frequency specific offset (Offset _{nonservingcell}) associated with the second cell 410b, or the hysteresis associated with the handover process. In some implementations, the RSCP _{nonservingcell} may be the measurement result of the second cell 410b. The RSCP _{nonservingcell} may indicate the signal strength (such as the received signal code power (RSCP) ) associated with the one or more signals transmitted by the second BS 105b. In certain implementations, the hysteresis may be a parameter used within the entry and leave condition of an event triggered the reporting condition.

In an aspect of the present disclosure, the UE 110 may determine the value of RSCP _{nonservingcell} + Offset _{nonservingcell} –hysteresis. If the value is less than or equal to a threshold parameter (threshold _{nonservingcell}) associated with the handover process, the UE 110 may remain with the first cell 410a. If the value is greater than the threshold _{nonservingcell} during a time interval time-to-trigger, the UE 110 may transmit an indication (e.g., B1 event) to the first cell 410a via the first BS 105a to trigger the handover process from the first cell 410a operating using the first technology to the second cell 410b operating using the second technology, or the handover process to add the second cell 410b as a secondary cell/cell group.

In some implementations, after the UE 110 transmits the indication triggering the handover process, the first cell 410a may transmit a handover request, via the backhaul links 132, 134, to the second cell 410b. In response, the second cell 410b may transmit a handover grant to the first cell 410a. The first cell 410a may transmit a first radio resource control (RRC) reconfiguration message to the UE 110 indicating that the UE 110 may begin performing the synchronization (e.g., receiving synchronization blocks from the second cell 410b) and random access (e.g., physical random access channel connection) processes. After the completion of the random access process, the second cell 410b may transmit a second RRC reconfiguration message to the UE 110 to establish the connection between the UE 110 and the second cell 410b.

Fig. 5 illustrates an example of a process for performing handover. In some implementations, the process 500 may be performed by one or more of the UE 110, the first cell 410a, and/or the second cell 410b. At 502, the UE 110 may be connected to the first cell 410a. In some instances, the UE 110 may be operating in E-UTRA NR dual connectivity (ENDC) mode. For example, the UE 110 may be camping on the first cell 410a (e.g., an LTE anchor cell) while connected to a secondary cell (e.g., 5G NSA, not shown) .

At 504, the UE 110 may determine whether the channel quality is lower than the threshold. For example, the UE 110 may receive one or more RSs from the first cell 410a. The UE 110 may measure, based on the one or more RSs, at least one of the RSRP, RSRQ, RSSI, SNR and/or SINR. In one aspect, the UE 110 may compare the RSRP with a threshold RSRP (RSRP _Thresh) . If the RSRP is greater than or equal to the RSRP _Thresh (e.g., RSRP ≥ -105 decibel milliwatt (dBm) ) , the UE 110 may determine to remain in the first cell 410a. Alternatively or additionally, the UE 110 may compare the SNR with a threshold SNR (SNR _Thresh) . If the SNR is greater than or equal to the SNR _Thresh (e.g., SNR ≥ 10 decibel (dB) ) , the UE 110 may determine to remain in the first cell 410a. The threshold values (e.g., RSRP _Thresh or SNR _Thresh) may be stored in the UE 110 or transmitted by the first cell 410a.

In some aspects, if the RSRP is less than the RSRP _Thresh (e.g., RSRP < -105 decibel milliwatt (dBm) ) , the UE 110 may determine to evaluate a handover condition. Alternatively or additionally, the SNR is less than the SNR _Thresh (e.g., SNR < 10 decibel (dB) ) , the UE 110 may determine to evaluate the handover condition.

At 506, the UE 110 may determine whether the handover condition is met. In an aspect of the present disclosure, the UE 110 may determine the value of RSCP _{nonservingcell} + Offset _{nonservingcell} –hysteresis. If the value is less than or equal to a threshold parameter (threshold _{nonservingcell}) associated with the handover process, the UE 110 may remain with the first cell 410a. If the value is greater than the threshold _{nonservingcell}during a time interval time-to-trigger, the UE 110 may determine to trigger the handover process to add the second cell 410b as a secondary cell/cell group.

At 508, the UE 110 may transmit an indication (e.g., B1 event) to the first cell 410a via the first BS 105a to trigger the handover process to add the second cell 410b as a secondary cell/cell group.

At 510, the UE 110, the first cell 410a, and/or the second cell 410b may perform the handover process. In certain implementations, the first cell 410a may transmit a handover request, via the backhaul links 132, 134, to the second cell 410b. In response, the second cell 410b may transmit a handover grant to the first cell 410a. The first cell 410a may transmit a first radio resource control (RRC) reconfiguration message to the UE 110 indicating that the UE 110 may begin performing the synchronization (e.g., receiving synchronization blocks from the second cell 410b) and random access (e.g., physical random access channel connection) processes. After the completion of the random access process, the second cell 410b may transmit a second RRC reconfiguration message to the UE 110 to establish the connection between the UE 110 and the second cell 410b.

Fig. 6 illustrates an example of a method for performing handover by the UE. For example, a method 600 may be performed by the one or more of the processor 212, the memory 216, the applications 275, the modem 220, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the communication component 222 and/or the determination component 224, and/or one or more other components of the UE 110 in the wireless communication network 100.

At block 605, the method 600 may establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode. For example, the communication component 222, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 of the UE 110 may establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode as described above.

In certain implementations, the communication component 222, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 may be configured to and/or may define means for establishing a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode.

At block 610, the method 600 may receive one or more reference signals from the first cell. For example, the communication component 222, the transceiver 202, the receiver 206, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 of the UE 110 may establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode as described above. The RF front end 288 may receive the electrical signals converted from electro-magnetic signals. The RF front end 288 may filter and/or amplify the electrical signals. The transceiver 202 or the receiver 206 may convert the electrical signals to digital signals, and send the digital signals to the communication component 222.

In certain implementations, the communication component 222, the transceiver 202, the receiver 206, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 may be configured to and/or may define means for receiving one or more reference signals from the first cell.

At block 615, the method 600 may determine a channel quality associated with the second cell based on the one or more reference signals. For example, the determination component 224, the processor 212, the memory 216, the modem 220, and/or the applications 275 of the UE 110 may determine a channel quality associated with the second cell based on the one or more reference signals.

In certain implementations, the determination component 224, the processor 212, the memory 216, the modem 220, and/or the applications 275 may be configured to and/or may define means for determining a channel quality associated with the second cell based on the one or more reference signals.

At block 620, the method 600 may determine whether a channel quality is lower than a threshold. For example, the determination component 224, the processor 212, the memory 216, the modem 220, and/or the applications 275 of the UE 110 may determine whether a channel quality is lower than a threshold.

In certain implementations, the determination component 224, the processor 212, the memory 216, the modem 220, and/or the applications 275 may be configured to and/or may define means for determining whether a channel quality is lower than a threshold.

At block 625, the method 600 may determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold. For example the communication component 222, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 of the UE 110 may determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold.

In certain implementations, the communication component 222, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 may be configured to and/or may define means for determining whether a handover condition is satisfied in response to the channel quality being lower than the threshold.

At block 630, the method 600 may establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.. For example, the communication component 222, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 of the UE 110 may establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell. as described above.

In certain implementations, the communication component 222, the transceiver 202, the receiver 206, the transmitter 208, the RF front end 288, the subcomponents of the RF front end 288, the processor 212, the memory 216, the modem 220, and/or the applications 275 may be configured to and/or may define means for establishing a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.

Alternatively or additionally, the method 600 may further include any of the methods above, further comprising, maintaining the first connection to the first cell without establishing the second connection to the second cell in response to the channel quality being higher than or equal to the threshold.

Alternatively or additionally, the method 600 may further include any of the methods above, further comprising, maintaining the first connection to the first cell without establishing the second connection to the second cell in response to the handover condition being not satisfied.

Alternatively or additionally, the method 600 may further include any of the methods above, wherein the channel quality comprises a reference signal received power (RSRP) or a signal to noise ratio (SNR) .

Alternatively or additionally, the method 600 may further include any of the methods above, wherein determining whether the channel quality is lower than the threshold comprises determining whether the RSRP is less than -105 decibel milliwatts.

Alternatively or additionally, the method 600 may further include any of the methods above, wherein determining whether the channel quality is lower than the threshold comprises determining whether the SNR is less than 10 decibel.

Alternatively or additionally, the method 600 may further include any of the methods above, wherein the handover condition is satisfied is satisfied when

Alternatively or additionally, the method 600 may further include any of the methods above, wherein establishing the second connection to the second cell comprises establishing the second connection to the second cell while maintaining the first connection to the first cell.

The above detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The term “example, ” when used in this description, means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Also, 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 other examples. In some instances, well-known structures and apparatuses are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

It should be noted that the techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms “system” and “network” are often used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (, IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM ^TM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) . 3GPP LTE and LTE-Advanced (LTE-A) are new 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) . The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description herein, however, describes an LTE/LTE-Asystem or 5G system for purposes of example, and LTE terminology is used in much of the description below, although the techniques may be applicable other next generation communication systems.

Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a specially-programmed device, such as but not limited to a processor, a digital signal processor (DSP) , an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. A specially-programmed processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A specially-programmed processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above may be implemented using software executed by a specially programmed processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) .

Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium that may be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. 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, 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 Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Furthermore, although elements of the described aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect may be utilized with all or a portion of any other aspect, unless stated otherwise. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Method to improve IRAT handover over NR5G

INVENTION DESCRIPTION:

Compared with LTE and UMTS/HDR/TDSCDMA, 5G NR device would provide higher DL/UL data throughput, better power saving, etc.

Considering device is capable to stably stay on 5G NR,

This invention introduces a network selection way at cross area with LTE, 5GNR and 3G available

Design Example:

- Device register on LTE anchor cell.

- Add SCG on LTE anchor cell to get NSA NR5G service

- Device handling IRAT handover by evaluating below condition and report event B1 if it is meet.

RSCPnonservingcell + Offsetnonservingcell -Hysteresis ＞ Threshnonservingcell during a time interval TimeToTrigger

- NW may trigger IRAT handover to 23G because received event B1

- This design cause device failed to stably get NSA NR5G service.

Flow chart:

Description:

- Device register on LTE anchor cell.

- Add SCG on LTE anchor cell to get NSA NR5G service

- Before handling IRAT handover event, device firstly evaluate LTE Serving cell’s RSRP/RSRQ and SNR.

RSRPservingcell ＜ Threshold_RSRP (e.g. RSRP ＜ -115 dbm) OR

SNR ＜ Threshold_SNR (e.g. SNR ＜ 10)

- When above criteria is meet, device may handling IRAT handover event B1

- This invention will be helpful to device stably stay on LTE anchor cell so as to get NSA NR5G service

Flow chart:

5.5.4.7 Event B1 (Inter RAT neighbour becomes better than threshold)

The UE shall:

1＞ for UTRA and CDMA2000, trigger the event for cells included in the corresponding measurement object;

1＞ consider the entering condition for this event to be satisfied when condition B1-1, as specified below, is fulfilled;

Inequality B1-1 (Entering condition)

Mn+Ofn-Hys＞Thresh

The variables in the formula are defined as follows:

Mn is the measurement result of the inter-RAT neighbour cell, not taking into account any offsets. For CDMA 2000 measurement result, pilotStrength is divided by -2.

Ofn is the frequency specific offset of the frequency of the inter-RAT neighbour cell (i.e. offsetFreq as defined within the measObject corresponding to the frequency of the neighbour inter-RAT cell) .

Hys is the hysteresis parameter for this event (i.e. hysteresis as defined within reportConfigInterRAT for this event) .

Thresh is the threshold parameter for this event (i.e. b1-Threshold as defined within reportConfigInterRAT for this event) . For CDMA2000, b1-Threshold is divided by -2.

Mn is expressed in dBm or in dB, depending on the measurement quantity of the inter-RAT neighbour cell.

Ofn, Hys are expressed in dB.

Thresh is expressed in the same unit as Mn.

Claims

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

establishing a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode;

receiving one or more reference signals from the first cell;

determining a channel quality associated with the second cell based on the one or more reference signals;

determining whether a channel quality is lower than a threshold;

determining whether a handover condition is satisfied in response to the channel quality being lower than the threshold; and

establishing a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.
The method of claim 1, further comprising:

maintaining the first connection to the first cell without establishing the second connection to the second cell in response to the channel quality being higher than or equal to the threshold.
The method of claim 1, further comprising:

maintaining the first connection to the first cell without establishing the second connection to the second cell in response to the handover condition being not satisfied.
The method of claim 1, wherein:

the channel quality comprises a reference signal received power (RSRP) or a signal to noise ratio (SNR) .
The method of claim 4, wherein determining whether the channel quality is lower than the threshold comprises:

determining whether the RSRP is less than -105 decibel milliwatts.
The method of claim 4, wherein determining whether the channel quality is lower than the threshold comprises:

determining whether the SNR is less than 10 decibel.
The method of claim 1, wherein:

the handover condition is satisfied is satisfied when

RSCP _{nonservingcell} + Offset _{nonservingcell} –hysteresis > threshold _{nonservingcell} during a time interval.
The method of claim 1, wherein establishing the second connection to the second cell comprises:

establishing the second connection to the second cell while maintaining the first connection to the first cell.
A user equipment (UE) , comprising:

a memory comprising instructions;

a transceiver; and

one or more processors operatively coupled with the memory and the transceiver, the one or more processors configured to execute instructions in the memory to:

establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode;

receive one or more reference signals from the first cell;

determine a channel quality associated with the second cell based on the one or more reference signals;

determine whether a channel quality is lower than a threshold;

determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold; and

establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.
The user equipment (UE) of claim 11, wherein the one or more processors are further configured to:

maintain the first connection to the first cell without establishing the second connection to the second cell in response to the channel quality being higher than or equal to the threshold.
The user equipment (UE) of claim 11, wherein the one or more processors are further configured to:

maintain the first connection to the first cell without establishing the second connection to the second cell in response to the handover condition being not satisfied.
The user equipment (UE) of claim 11, wherein:

the channel quality comprises a reference signal received power (RSRP) or a signal to noise ratio (SNR) .
The user equipment (UE) of claim 14, wherein determining whether the channel quality is lower than the threshold comprises:

determine whether the RSRP is less than -105 decibel milliwatts.
The user equipment (UE) of claim 14, wherein determining whether the channel quality is lower than the threshold comprises:

determine whether the SNR is less than 10 decibel.
The user equipment (UE) of claim 11, wherein:

the handover condition is satisfied is satisfied when

RSCP _{nonservingcell} + Offset _{nonservingcell} –hysteresis > threshold _{nonservingcell} during a time interval.
The user equipment (UE) of claim 11, wherein establishing the second connection to the second cell comprises:

establish the second connection to the second cell while maintaining the first connection to the first cell.
A non-transitory computer readable medium having instructions stored therein that, when executed by one or more processors of a user equipment (UE) , cause the one or more processors to:

establish a first connection to a first cell, wherein the UE is operating in Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) dual connectivity (ENDC) mode;

receive one or more reference signals from the first cell;

determine a channel quality associated with the second cell based on the one or more reference signals;

determine whether a channel quality is lower than a threshold;

determine whether a handover condition is satisfied in response to the channel quality being lower than the threshold; and

establish a second connection to a second cell in response to the handover condition being satisfied, wherein the second cell is one of a Universal Mobile Telecommunications System (UMTS) cell or a Global Systems for Mobile (GSM) cell.
The non-transitory computer readable medium of claim 21, further comprising instructions, when executed by the one or more processors, cause the one or more processors to:

maintain the first connection to the first cell without establishing the second connection to the second cell in response to the channel quality being higher than or equal to the threshold.
The non-transitory computer readable medium of claim 21, further comprising instructions, when executed by the one or more processors, cause the one or more processors t, in response to determining the handover condition is not satisfied:

maintain the first connection to the first cell without establishing the second connection to the second cell in response to the handover condition being not satisfied.
The non-transitory computer readable medium of claim 21, wherein:

the channel quality comprises a reference signal received power (RSRP) or a signal to noise ratio (SNR) .
The non-transitory computer readable medium of claim 24, wherein the instructions for determining whether the channel quality is lower than the threshold further comprises instructions, when executed by the one or more processors, cause the one or more processors to:

determine whether the RSRP is less than -105 decibel milliwatts.
The non-transitory computer readable medium of claim 24, wherein the instructions for determining whether the channel quality is lower than the threshold further comprises instructions, when executed by the one or more processors, cause the one or more processors to:

determine whether the SNR is less than 10 decibel.
The non-transitory computer readable medium of claim 21, wherein:

the handover condition is satisfied is satisfied when

RSCP _{nonservingcell} + Offset _{nonservingcell} –hysteresis > threshold _{nonservingcell} during a time interval.
The non-transitory computer readable medium of claim 21, wherein the instructions for establishing the second connection to the second cell further comprises instructions, when executed by the one or more processors, cause the one or more processors to:

establish the second connection to the second cell while maintaining the first connection to the first cell.