PATENT DOCUMENT

Publication Number: US-11375421-B2
Application Number: US-202016800887-A
Country: US
Kind Code: B2

Title: Cell handover in a radio cellular system

Abstract:
When user equipment (UE) is to be handed over, the network and/or the UE determines a best beam for the UE&#39;s interactions with the target cell before the handover is completed. One or more additional next best beams may also be determined. The network (e.g., the target cell) allocates one or more uplink (UL) grants that corresponds to the best beam. Via a current cell, the UE receives the one or more UL grants from the network pertaining to communications between the UE and the target cell. The UE determines whether any beams of the one or more UL grants satisfy beam criteria. The beam criteria may include 1) an allocated beam being the current best beam or 2) an allocated beam being within a strength threshold of the current best beam. If the criteria is not satisfied, the UE initiates another handover type (e.g., a RACH-based handover).

Claims:
What is claimed is: 
     
       1. An electronic device; comprising:
 a network interface configured to interface with a cellular network; 
 a memory storing instructions; 
 a processor configured to execute the instructions, wherein, when the instructions are executed, are configured to cause the processor to: 
 use the network interface to measure beams of a target cell of the cellular network, wherein the target cell is a cell of the cellular network to which the electronic device is to be handed over; 
 send, via the network interface, a measurement report to a current cell of the cellular network; 
 receive, via the network interface, an uplink (UL) grant, wherein the UL grant corresponds to a beam of the beams from the target cell of the cellular network to the electronic device, wherein the UL grant is received as part of a handover from the current cell to the target cell; 
 perform the handover to the target cell using the beam without using a random access channel (RACH) procedure; 
 after the handover, measure the beams of the target cell, including the beam, and determine whether the beam satisfies a criteria for a target cell best beam for communication between the electronic device and the target cell; and 
 in response to determining that the beam does not satisfy the criteria, initiate a RACH-based handover to update to the target cell best beam for the communication between the electronic device and the target cell. 
 
     
     
       2. The electronic device of  claim 1 , wherein receiving the UL grant comprises receiving the UL grant from the current cell. 
     
     
       3. The electronic device of  claim 2 , wherein the UL grant is allocated by the target cell. 
     
     
       4. The electronic device of  claim 1 , wherein determining whether the beam satisfies the criteria, comprises measuring beams of the target cell via the network interface to determine whether a new best beam exists. 
     
     
       5. The electronic device of  claim 4 , wherein, when no new best beam exists, the instructions are configured to cause the processor to continue using the beam to communicate with the target cell via the network interface when the criteria has been satisfied by the beam, wherein the beam is the best beam. 
     
     
       6. The electronic device of  claim 4 , wherein, when the new best beam exists, the instructions are configured to cause the processor to:
 determine whether the new best beam corresponds to one of a plurality of UL grants, wherein the plurality of UL grants comprises the UL grant; and 
 when the new best beam corresponds to one of the plurality of UL grants, switch communications to the new best beam from the beam for communications with the target cell via the network interface, wherein the criteria is satisfied when the new best beam corresponds to the one of the plurality of UL grants, and the criteria is not satisfied when the new best beam does not correspond to the one of the plurality of UL grants. 
 
     
     
       7. The electronic device of  claim 4 , wherein the instructions are configured to cause the processor to:
 determine whether the beam is within a strength threshold of the new best beam; and 
 when the beam is within the strength threshold, identify that the criteria has been satisfied and utilize the beam to communicate with the target cell via the network interface. 
 
     
     
       8. The electronic device of  claim 7 , wherein the beam comprises an allocated best beam that was the best beam at the time of allocation of the beam. 
     
     
       9. The electronic device of  claim 7 , wherein the strength threshold is defined by the cellular network in a signal received by the electronic device via the network interface. 
     
     
       10. The electronic device of  claim 7 , wherein the strength threshold is defined by the electronic device. 
     
     
       11. The electronic device of  claim 7 , wherein the strength threshold is set to a value indicated by a radio performance and protocol and radio resource management standard. 
     
     
       12. The electronic device of  claim 1 , wherein the instructions are configured to cause the processor, via the network interface, to measure beams of the target cell before the handover. 
     
     
       13. The electronic device of  claim 12 , wherein the instructions are configured to cause the processor to send the measurement report, via the network interface, to the current cell regarding the measurement of the beams of the target cell. 
     
     
       14. The electronic device of  claim 1 , wherein the beam comprises an allocated best beam that was the best beam at the time of allocation of the plurality of beams. 
     
     
       15. A method, comprising:
 using a network interface of an electronic device, measuring beams of a target cell of a cellular network, wherein the target cell is a cell of the cellular network to which the electronic device is to be handed over; 
 sending, via the network interface, a measurement report to a current cell of the cellular network; 
 receiving, via the current cell and the network interface, an uplink (UL) grant corresponding to a beam of the beams of the target cell to be used in communication between the electronic device and the target cell; 
 performing handover to the target cell using the beam without using a random access channel (RACH) procedure; 
 after the handover, measuring the beams of the target cell, wherein the beams include the beam; 
 determining whether the beam is within a strength threshold of a target cell best beam; and 
 when the beam is not within the strength threshold of the target cell best beam, initiating a RACH-based handover to update to the target cell best beam for communications between the electronic device and the target cell. 
 
     
     
       16. The method of  claim 15 , wherein measuring the target cell comprises using a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS). 
     
     
       17. The method of  claim 15 , comprising, after the handover, measuring the target cell to obtain the target cell best beam. 
     
     
       18. The method of  claim 15 , wherein the strength threshold comprises a number of decibels. 
     
     
       19. The method of  claim 15 , wherein the strength threshold comprises 0.0 decibels to cause the initiating of the RACH-based handover unless the beam remains the target cell best beam.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from and the benefit of U.S. Provisional Application Ser. No. 62/888,073, entitled “CELL HANDOVER IN A RADIO CELLULAR SYSTEM”, filed Aug. 16, 2019, which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to wireless communication systems and, more specifically, to systems and methods for cell handover in new radio (NR) system. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     In cellular communication networks, each basestation of a cellular network covers a specific area or cell. When a mobile device moves between cells, communications between the mobile device and the cellular network is handed over from a current cell to a target cell. The change of cells may be attributed to physical movement of the mobile device or other reasons (e.g., the previous cell becomes unavailable/has lower performance and/or is overly congested). The handover may cause temporary interruption of communication between the mobile device and the cellular network. 
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     Cellular communications networks enable handover of user equipment (UE) between a current cell and a target cell. When the UE is to be handed over, the network and/or the UE determines a best beam for the UE&#39;s interactions with the target cell before the handover is completed. The network and/or the UE may determine one or more additional next best beams. The network (e.g., the target cell) allocates an uplink (UL) grant that corresponds to the best beam. In some embodiments, the network may allocate additional UL grants that correspond to the one or more additional next best beams. 
     The UE may measure the target cell before the handover and send a measurement report to the current cell of the network before the handover is completed. Via the current cell, the UE receives one or more UL grants from the network (e.g., current cell) pertaining to communications between the UE and the target cell. After handover, the UE determines a current best beam. The UE determines whether one of the one or more UL grants corresponds to an allocated beam that satisfies beam criteria. The beam criteria may include 1) the allocated beam being the current best beam or 2) the allocated beam being within a strength threshold (e.g., a defined number of decibels) of the current best beam. If the criteria is satisfied, the UE uses the allocated beam for future communication with the target cell. If the criteria is not satisfied, the UE initiates another handover type (e.g., a RACH-based handover). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram of an electronic device that includes an antenna, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a perspective view of a notebook computer representing an embodiment of the electronic device of  FIG. 1 ; 
         FIG. 3  is a front view of a hand-held device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 4  is a front view of another hand-held device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 5  is a front view of a desktop computer representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 6  is a front view and side view of a wearable electronic device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 7  is a diagram of a cellular network that connects to the electronic device of  FIG. 1 , in accordance with embodiments of the present disclosure; 
         FIG. 8  is a diagram of a cellular network that connects to the electronic device of  FIG. 1  using a beam management framework, in accordance with embodiments of the present disclosure; 
         FIG. 9  is a flow diagram of a process of the cellular network of  FIG. 8  allocating one or more uplink (UL) grants, in accordance with embodiments of the present disclosure; 
         FIG. 10  is a flow diagram of a process of the electronic device performing a cell handover in the cellular network of  FIG. 8  when the cellular network allocates one UL grant, in accordance with embodiments of the present disclosure; and 
         FIG. 11  is a flow diagram of a process of the electronic device performing a cell handover in the cellular network of  FIG. 8  when the cellular network allocates multiple UL grants, in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     As previously discussed, handovers of a mobile device between cells of a cellular network may result an interruption of data communication between the cellular network and the mobile device. To perform the handover, a random access channel (RACH) may be used by the cellular network. The RACH is a shared channel used by the mobile device to set-up calls and to establish how the communications are to be performed with the new cell in a handover. To reduce the interruption time, the handovers may utilize a make-before-break procedure (MBB) that establishes a new connection for the mobile device to the target cell before a connection to the current cell is broken. With the use of synchronized base stations, a RACH-less handover may be used to decrease target cell access time to further reduce the period of interruption due to the handover. 
     As discussed below, the use of a RACH-less handover may create issues in 5G new radio (NR) that utilizes beam management. When using RACH in cellular networks that utilize beam management, the RACH phase may be used to establish beams used in communications using the cellular networks having beam management frameworks. However, when the mobile device skips the RACH phase, the mobile device is pre-allocated an uplink (UL) grant in the target cell to which the mobile device is being handed over. The UL grant is used to enable a data transfer between the mobile device and the target cell. In some embodiments, the UL grant has a set delay period (e.g., 4 ms) between receipt of the UL grant and beginning the data transfer to the target cell. Ideally, the beam corresponding to the UL grant in NR systems is the best beam for the connection between the basestation and the mobile device. However, even though the network and/or the mobile device may determine the best beam, the beam used for the mobile device may not be the best beam for the communications between the basestation and the mobile device after the handover. For example, between the allocation of the UL grant to the mobile device and the establishment of the connection between the mobile device and the basestation of the target cell, a current best may have changed and may be different than the pre-allocated beam. Without the RACH phase, the mobile device is unable to indicate which beam is the best beam to the basestation of the target cell. Without this indication, the target cell&#39;s basestation may continue using the originally allocated beam even though the allocated beam is not the best beam. 
     With the foregoing in mind, there are many suitable electronic devices that may benefit from the embodiments for cellular handovers described herein. Turning first to  FIG. 1 , an electronic device  10  according to an embodiment of the present disclosure may include, among other things, one or more processor(s)  12 , memory  14 , nonvolatile storage  16 , a display  18 , antenna(s)  20 , input structures  22 , an input/output (I/O) interface  24 , and a network interface  25 . The various functional blocks shown in  FIG. 1  may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium) or a combination of both hardware and software elements. It should be noted that  FIG. 1  is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in electronic device  10 . 
     By way of example, the electronic device  10  may represent a block diagram of the notebook computer depicted in  FIG. 2 , the handheld device depicted in  FIG. 3 , the handheld device depicted in  FIG. 4 , the desktop computer depicted in  FIG. 5 , the wearable electronic device depicted in  FIG. 6 , or similar devices. It should be noted that the processor(s)  12  and other related items in  FIG. 1  may be generally referred to herein as “data processing circuitry.” Such data processing circuitry may be embodied wholly or in part as software, firmware, hardware, or any combination thereof. Furthermore, the data processing circuitry may be a single contained processing module or may be incorporated wholly or partially within any of the other elements within the electronic device  10 . 
     In the electronic device  10  of  FIG. 1 , the processor(s)  12  may be operably coupled with the memory  14  and the nonvolatile storage  16  to perform various algorithms. Such programs or instructions executed by the processor(s)  12  may be stored in any suitable article of manufacture that includes one or more tangible, computer-readable media at least collectively storing the instructions or routines, such as the memory  14  and the nonvolatile storage  16 . The memory  14  and the nonvolatile storage  16  may include any suitable articles of manufacture for storing data and executable instructions, such as random-access memory, read-only memory, rewritable flash memory, hard drives, and optical discs. In addition, programs (e.g., an operating system) encoded on such a computer program product may also include instructions that may be executed by the processor(s)  12  to enable the electronic device  10  to provide various functionalities. 
     In certain embodiments, the display  18  may be a liquid crystal display (LCD), which may allow users to view images generated on the electronic device  10 . In some embodiments, the display  18  may include a touch screen, which may allow users to interact with a user interface of the electronic device  10 . Furthermore, it should be appreciated that, in some embodiments, the display  18  may include one or more organic light emitting diode (OLED) displays, or some combination of LCD panels and OLED panels. 
     The input structures  22  of the electronic device  10  may enable a user to interact with the electronic device  10  (e.g., pressing a button to increase or decrease a volume level). The I/O interface  24  may enable electronic device  10  to interface with various other electronic devices, as may the network interface  25 . The network interface  25  may include, for example, one or more interfaces for a personal area network (PAN), such as a Bluetooth network, for a local area network (LAN) or wireless local area network (WLAN), such as an 802.11x Wi-Fi network, and/or for a wide area network (WAN), such as a 3rd generation (3G) cellular network, universal mobile telecommunication system (UMTS), 4th generation (4G) cellular network, long term evolution (LTE) cellular network, or long term evolution license assisted access (LTE-LAA) cellular network, 5th generation (5G) cellular network, and/or 5G New Radio (5G NR) cellular network. The network interface  25  may also include one or more interfaces for, for example, broadband fixed wireless access networks (WiMAX), mobile broadband Wireless networks (mobile WiMAX), asynchronous digital subscriber lines (e.g., ADSL, VDSL), digital video broadcasting-terrestrial (DVB-T) and its extension DVB Handheld (DVB-H), ultra-Wideband (UWB), alternating current (AC) power lines, and so forth. For example, network interfaces  25  may be capable of joining multiple networks, and may employ one or more antennas  20  to that end. 
     As further illustrated, the electronic device  10  may include a power source  29 . The power source  29  may include any suitable source of power, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. 
     In certain embodiments, the electronic device  10  may take the form of a computer, a portable electronic device, a wearable electronic device, or other type of electronic device. Such computers may include computers that are generally portable (such as laptop, notebook, and tablet computers) as well as computers that are generally used in one place (such as conventional desktop computers, workstations, and/or servers). In certain embodiments, the electronic device  10  in the form of a computer may be a model of a MACBOOK®, MACBOOK® PRO, MACBOOK AIR®, IMAC®, MAC® MINI, OR MAC PRO® available from Apple Inc. By way of example, the electronic device  10 , taking the form of a notebook computer  10 A, is illustrated in  FIG. 2  in accordance with one embodiment of the present disclosure. The depicted computer  10 A may include a housing or enclosure  36 , a display  18 , input structures  22 , and ports of an I/O interface  24 . In one embodiment, the input structures  22  (such as a keyboard and/or touchpad) may be used to interact with the computer  10 A, such as to start, control, or operate a GUI or applications running on computer  10 A. For example, a keyboard and/or touchpad may allow a user to navigate a user interface or application interface displayed on display  18 . 
       FIG. 3  depicts a front view of a handheld device  10 B, which represents one embodiment of the electronic device  10 . The handheld device  10 B may represent, for example, a portable phone, a media player, a personal data organizer, a handheld game platform, or any combination of such devices. By way of example, the handheld device  10 B may be a model of an IPOD® OR IPHONE® available from Apple Inc. of Cupertino, Calif. The handheld device  10 B may include an enclosure  36  to protect interior components from physical damage and to shield them from electromagnetic interference. The enclosure  36  may surround the display  18 . The I/O interfaces  24  may open through the enclosure  36  and may include, for example, an I/O port for a hardwired connection for charging and/or content manipulation using a standard connector and protocol, such as the Lightning connector provided by Apple Inc., a universal serial bus (USB), or other similar connector and protocol. 
     User input structures  22 , in combination with the display  18 , may allow a user to control the handheld device  10 B. For example, the input structures  22  may activate or deactivate the handheld device  10 B, navigate user interface to a home screen, a user-configurable application screen, and/or activate a voice-recognition feature of the handheld device  10 B. Other input structures  22  may provide volume control, or may toggle between vibrate and ring modes. The input structures  22  may also include a microphone may obtain a user&#39;s voice for various voice-related features, and a speaker may enable audio playback and/or certain phone capabilities. The input structures  22  may also include a headphone input may provide a connection to external speakers and/or headphones. 
       FIG. 4  depicts a front view of another handheld device  10 C, which represents another embodiment of the electronic device  10 . The handheld device  10 C may represent, for example, a tablet computer, or one of various portable computing devices. By way of example, the handheld device  10 C may be a tablet-sized embodiment of the electronic device  10 , which may be, for example, a model of an IPAD® available from Apple Inc. of Cupertino, Calif. 
     Turning to  FIG. 5 , a computer  10 D may represent another embodiment of the electronic device  10  of  FIG. 1 . The computer  10 D may be any computer, such as a desktop computer, a server, or a notebook computer, but may also be a standalone media player or video gaming machine. By way of example, the computer  10 D may be an IMAC®, a MACBOOK®, or other similar device by Apple Inc. It should be noted that the computer  10 D may also represent a personal computer (PC) by another manufacturer. A similar enclosure  36  may be provided to protect and enclose internal components of the computer  10 D such as the display  18 . In certain embodiments, a user of the computer  10 D may interact with the computer  10 D using various peripheral input structures  22 , such as the keyboard  22 A or mouse  22 B, which may connect to the computer  10 D. 
     Similarly,  FIG. 6  depicts a wearable electronic device  10 E representing another embodiment of the electronic device  10  of  FIG. 1  that may be configured to operate using the techniques described herein. By way of example, the wearable electronic device  10 E, which may include a wristband  43 , may be an APPLE WATCH® by Apple Inc. However, in other embodiments, the wearable electronic device  10 E may include any wearable electronic device such as, for example, a wearable exercise monitoring device (e.g., pedometer, accelerometer, heart rate monitor), or other device by another manufacturer. The display  18  of the wearable electronic device  10 E may include a touch screen display  18  (e.g., LCD, OLED display, active-matrix organic light emitting diode (AMOLED) display, and so forth), as well as input structures  22 , which may allow users to interact with a user interface of the wearable electronic device  10 E. 
     With the foregoing in mind,  FIG. 7  illustrates an example of cellular communications network  100  to which the electronic device  10  connects. Although the electronic device  10  is illustrated as a cellular phone, the cellular communications network  100  may connect to any electronic device that has a corresponding radio, such as an LTE or 5G radio, as part of its network interface  25  and antenna  20 . The cellular communications network  100  includes a basestation  102  that is used to implement at least a portion of a cell  104 . Similarly, the cellular communications network  100  includes a basestation  106  that is used to implement at least a portion of a cell  108 . The basestations  102  and  106  may include and/or utilize a computing device (e.g., another iteration of the electronic device  10 ) to perform computations and/or implement program code to perform specific tasks. 
     At some point, the connection to the basestation  102  becomes less desirable than a connection to the basestation  106 . This change may be due to the electronic device  10  exiting the cell  104  or the basestation  102  otherwise becoming congested/unavailable to the electronic device  10 . At this point, the electronic device  10  is handed over from the cell  103  to the cell  108 . In some embodiments, the handover may utilize a Random Access Channel (RACH) of the basestation  106  to setup the connection between the basestation  106  and the electronic device  10 . However, due to the break of the connection between the electronic device  10  and the basestation  102  and establishment of the connection between the electronic device  10  and the basestation  106 , the electronic device  10  may undergo a temporary interruption of service due to the handover. To reduce this interruption, a make-before-break (MBB) handover may be made. During an MBB handover, the connection between the basestation  106  and the electronic device  10  may be made before the connection between the basestation  102  and the electronic device  10  may be broken. Furthermore, due to availability of synchronization between the basestations  102  and  106 , the setup of the connection between the basestation  106  and the electronic device  10  may be performed without using the RACH in a RACH-less handover. A RACH-less handover further reduces the handover delay and it associated interruption time due to the handover. A RACH-less mechanism (as applied to LTE) includes a pre-allocation of an uplink (UL) grant in the cell  108  since the RACH phase is skipped in the handover. A possible method of performing the pre-allocation includes allocating a fixed grant that are sent to the electronic device  10  via the cell  104  before the handover. An alternative method of performing the pre-allocation may include the cell  108  continuously performing the UL grant by using a user equipment (UE) cell-radio network temporary identifier (C-RNTI) that is typically used to transmit to a specific UE (e.g., the electronic device  10 ) after RACH when RACH is used. 
     For LTE and 5G NR Frequency Range  1  (FR1) less than 7 GHz, the previously RACH-less handover mechanism may be suitable for handovers. However, for 5G NR Frequency Range  2  (FR2) having a frequency greater than 7 GHz (e.g., 7-24 GHz) that utilize beam management frameworks, a RACH-less handover mechanism should account for beam management. 
       FIG. 8  illustrates a cellular communications network  110  that utilizes 5G NR FR2. As illustrated, a basestation  112  uses beams  114  and  116  to exchange information with UEs (e.g., electronic device  10 ) in a cell  118 . Similarly, a basestation  120  may use beams  122 ,  124 , and  126  to exchange information with UEs in a cell  128 . Although two beams (beams  114  and  116 ) are illustrated in the cell  118  and three beams (e.g., beams  122 ,  124 , and  126 ) are illustrated in the cell  128 , any suitable number of beams may be deployed within the cells  118  and  128 . During a RACH-based handover, the electronic device  10  may instruct the basestation  120  which beam should be used in transmitting data to the basestation  120 . For example, the basestation  120  may determine that beam  122  is the best beam for communications with the electronic device  10 . However, the best beam may change before and/or during the RACH phase. Accordingly, the electronic device  10  may instruct the basestation  120  that a different beam, beam  124 , is now the best beam for communications between the basestation  120  and the electronic device  10  since the best beam has changed. 
     Consequently, when a RACH-less handover occurs, the RACH phase is omitted, and the electronic device  10  is unable to directly instruct the basestation  120  as to which beam is the best. For example, in a RACH-less handover, the basestation  120  may rely on the beam  122  being the best beam from measurement reports (e.g., received from the basestation  112 ) even though the beam  124  is currently the best beam for communications between the electronic device  10  and the basestation  120 . In other words, without a RACH phase the communications between the electronic device  10  and the basestation  120  may use an inferior beam rather than the best beam thereby possibly reducing efficiency of communications between the electronic device  10  and the basestation  120 . 
     One approach that may be used to account for beam management frameworks (e.g., 5G NR FR2) includes allocating additional UL grants to the UE when a handover between cells occurs. For instance,  FIG. 9  illustrates a method  140  that may be implemented for the cell  128  to account for beam management. The method  140  may be performed using the basestation  120  and/or an associated computing device including a processor and memory similar to those discussed in relation to the electronic device  10 . For example, a computing device may be used to control network actions for the cell and/or within the cell  128 . For instance, in some embodiments, the computing device may be another instance of the computer  10 D. The network (e.g., using the computing device) receives an indication that user equipment is to be handed over from the cell  118  to the cell  128  (block  142 ). For instance, the indication may indicate that a strength-of-signal (SoS) for communications between the electronic device  10  and the cell  118  has fallen below a threshold. Additionally or alternatively, the indication may indicate that a SoS for communication with the cell  128  is likely to exceed another threshold. For instance, this likelihood may be made based on a determined location of the electronic device  10  in relation to where the basestation  120  is located. Based on measurement reports, the basestation  112 , the basestation  120 , another basestation, the electronic device  10 , and/or other processing within the network (e.g., central processing control center) determines a best beam (e.g., strongest beam) for communication between the electronic device  10  and the cell  128  (block  144 ). In some embodiments, the network may determine the best beam using a measurement report from the electronic device  10  or may determine the best beam by receiving an indication of the best beam from the electronic device  10 . 
     The network allocates one or more UL grants for the electronic device  10  to communicate with the cell  128  (block  146 ). For instance, the basestation  112 , the basestation  120 , another basestation, and/or other processing within the network (e.g., central processing control center) may be used to allocate the one or more UL grants. Granting the one or more UL grants may include sending the UL grants to the electronic device  10  for communication with the cell  128  by sending the UL grants via the cell  118 . 
     The one or more UL grants may be based at least in part on received measurements from the cell  118  from which the electronic device  10  is being handed off. The measurement report may be based on synchronization signal block (SSB) or channel state information reference signals (CSI-RS) that are used to estimate channel quality and report channel quality information. These measurement reports for communication between the cell  118  and the electronic device  10  may be used to determine the UL grants. Specifically, the one or more UL grants includes at least the best beam for communications between the electronic device  10  and the cell  128  based on measurements from the cell  118  that are transmitted to the electronic device  10  via the cell  118 . For example, the network may grant the electronic device  10  three UL grants that correspond to first, second, and third best beams based on the previous measurement reports. The network may grant the multiple UL grants to the electronic device  10  to account for the possibility that the beam designated as the best beam due to the previous reports may have changed before the handover is completed. For instance, the best beam may have changed since the measurements. In other words, even though the electronic device  10  may know some information about the cell  128  before the handover but the situation may change before the handover is completed. The additionally granted UL grants makes it more likely that the electronic device  10  is granted a UL grant that corresponds to the best beam at and/or after the handover is completed. Some deployments of 5G NR FR2 networks may use multiple UL grants to ensure best beam fidelity during a handoff while others use only a single UL grant to prevent the electronic device  10  from consuming too many resources within the cellular network. 
     The electronic device  10  responds to the number of UL grants according to the number of UL grants received.  FIG. 10  is a flow diagram of a process  150  that may be used by the electronic device  10  in a handover where the electronic device  10  is allocated one UL grant as part of the handover. The electronic device  10  measures a target cell (block  152 ). For instance, the electronic device  10  uses the antenna  20  to measure information about the cell  128  using SSB and/or CSI-RS. The electronic device  10  then sends a measurement report pertaining to the cell  128  via the cell  118  (block  154 ). The cell  128  allocates a UL grant corresponding to a best beam for a handover to the cell  128 . The electronic device  10  receives the UL grant from the cell  118  (block  156 ). The electronic device  10  then stores the best reported beam. The electronic device then performs the handover using the beam corresponding to the allocated UL grant (block  158 ). Performing the handover includes, after handing over, measuring beams for the cell  128 . The electronic device then compares the measured beams with the stored allocated beam to determine a current best beam. After the handover, the electronic device  10  determines whether the allocated beam satisfies criteria for the handover (block  160 ). In some embodiments, the criteria may be that the allocated beam is within a strength threshold (e.g., a number of decibels) of the current best beam. In some embodiments, the strength threshold may be determined according to standards, such as standards set by a radio performance and protocol aspects and radio resource management (RAN4 RRM) group. Additionally or alternatively, the threshold may be set to 0.0 dBs. In other words, the criteria may indicate that the allocated beam is to be used only when the allocated beam remains the best beam for communications between the electronic device  10  and the cell  128 . Regardless of the value, the strength threshold value may be a parameter that is set for the electronic device  10  using a signal received by the electronic device  10  from the cellular network. Additionally or alternatively, the strength threshold may be defined by the electronic device  10 . 
     Based on whether the connection with the cell  128  satisfies the criteria, the electronic device  10  determines how to proceed with further communication with the cell  128 . If allocated beam satisfies the criteria by being the best beam or within a strength threshold of the best beam, the electronic device  10  continues communication with the target cell using the allocated beam that corresponds to the allocated UL grant (block  162 ). However, if the allocated beam does not satisfying the criteria by being outside a strength threshold of the best beam, the electronic device  10  initiates a RACH procedure to update the beam using a RACH handover to allocate the best beam (block  164 ). For instance, the electronic device  10  may send a message to the basestation  112  and/or the basestation  120  to initiate the RACH handover. The RACH handover may include the UE measuring a RACH downlink (DL), transmitting measurements pertaining to the RACH DL to the network, and receiving a new UL grant. After receiving a new UL grant, the electronic device uses the newly allocated beam to communicate with the cell  128  (block  166 ). 
       FIG. 11  is a flow diagram of a process  170  that may be used by the electronic device  10  in a handover where the electronic device  10  is allocated two or more UL grants as part of the handover. The electronic device  10  measures a target cell (block  172 ). For instance, the electronic device  10  uses the antenna  20  to measure information about the cell  128  using SSB and/or CSI-RS. The electronic device  10  then sends a measurement report pertaining to beams of the cell  128  via the cell  118  (block  174 ). The cell  128  allocates two or more UL grants corresponding to the strongest two or more (e.g., 3) measured beams, including the best beam, for a handover to the cell  128 . The electronic device  10  receives the UL grants from the cell  118  (block  176 ). The electronic device  10  then stores the best reported beams that are allocated. The electronic device then performs the handover using the best beam corresponding to the allocated UL grants (block  178 ). Performing the handover includes, after handing over, measuring beams for the cell  128 . The electronic device then compares the measured beams with the stored allocated beams to determine a current best beam. After the handover, the electronic device  10  determines whether any of the allocated beam satisfy criteria for the handover (block  180 ). In some embodiments, the criteria may be that any of the allocated beams is within a strength threshold (e.g., a number of decibels) of the current best beam. As previously discussed, the strength threshold may be determined according to standards, such as standards set by a radio performance and protocol aspects and radio resource management (RAN4 RRM) group. Additionally or alternatively, the threshold may be set to 0.0 dBs. In other words, the criteria may indicate that one of the allocated beams is to be used only when the corresponding allocated beam is the current best beam for communications between the electronic device  10  and the cell  128 . Regardless of the value, the value of the strength threshold may be a parameter that is set for the electronic device  10  using a signal received by the electronic device  10  from the cellular network. Additionally or alternatively, the strength threshold may be defined by the electronic device  10 . 
     Based on whether the one of the allocated beams satisfies the criteria, the electronic device  10  determines how to proceed with further communication with the cell  128 . If any of the allocated beams satisfies the criteria by being the best beam or within a strength threshold of the best beam, the electronic device  10  continues communication with the target cell  128  using the best allocated beam that corresponds to the allocated UL grants (block  182 ). For example, the UL grants may correspond to beams  122 ,  124 , and  126 . The beam  122  may be the original measured best beam before the handover, while the beam  124  is the best beam after handover. Since the best beam is allocated to the electronic device  10 , the electronic device  10  may switch from using the beam  122  to using the beam  124  in communications with the cell  128 . 
     As previously discussed, in situations where a non-zero threshold is utilized, the allocated beams may not be the best beam but may be used for communication with the cell  128  as long as the used allocated beam is within the strength threshold of the current best beam. For example, consider that the beams  122 ,  124 , and  126  are allocated for the handover with the beam  122  being the best beam and an additional beam (not shown) is determined to be the best beam after handover. If the beams  122  and  124  are within the strength threshold of the additional beam, the beams  122  and  124  satisfy the criteria. The electronic device  10  then may use the beam  122  or the beam  124  for communication with the cell  128 . If the beam  122  is now less strong at the electronic device  10  than the beam  124 , the electronic device  10  may switch to using the beam  124  for communication with the cell  128 . Otherwise, the electronic device  10  may continue to use the beam  122  for communication with the cell  128 . 
     The electronic device  10  may switch between beams as long as the corresponding UL grants have not expired. In some embodiments, the UL grants may be prevented from expiring until an event has occurred to enable expiration of the unused UL grants. For example, the event may include a longer delay than a typical expiration during a handover and/or may include the electronic device  10  being handed over from the cell  128  to another cell. Additionally or alternatively, the event may include the electronic device  10  fully completing the handover and using one of the beams to initiate data transfer with the cell  128 . Additionally or alternatively, the event may include the electronic device  10  sending a release signal that indicates that the unused allocated UL grants are no longer needed. Thus, unless the event has occurred, the electronic device  10  is free to change between the allocated beams. 
     However, if none of the allocated beams satisfies the criteria by being within the strength threshold of the best beam, the electronic device  10  initiates a RACH procedure to update the beam using a RACH handover to allocate the best beam (block  184 ). For instance, the electronic device  10  may send a message to the basestation  112  and/or the basestation  120  to initiate the RACH handover. The RACH handover may include the UE measuring a RACH downlink (DL), transmitting measurements pertaining to the RACH DL to the network, and receiving a new UL grant. After receiving a new UL grant, the electronic device uses the newly allocated beam to communicate with the cell  128  (block  186 ). 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. For example, the processes may be applied for embodiments having different numbers and/or locations for antennas, different groupings, and/or different network arrangements. Moreover, it should be further understood that foregoing processes may be performed by suitable computing devices (e.g., the electronic device  10 ) using tangible, non-transitory, and computer-readable medium (e.g., the memory  14  and/or the storage  16 ) storing instructions that when performed by one or more processors (e.g., processor(s)  12 ) are configured to cause the one or more processors to perform the foregoing processes. Furthermore, it should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure. For example, various embodiments of the processes may include combinations of blocks, rearrangement of blocks, and/or additional blocks that includes subject matter that is within the spirit and scope of this disclosure. 
     The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Metadata:
Filing Date: 20200225
Publication Date: 20220628
Grant Date: 20220628
Priority Date: 20190816
Inventors: SAYENKO, ALEXANDER
IOFFE, ANATOLIY SERGEY
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/23", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/0833", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/0833", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/085", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/00725", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W56/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0695", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0051", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/0051", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/0833", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0058", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/046", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0058", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/046", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/0026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0051", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W56/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/0833", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0091", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0695", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W56/001", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W56/001", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/085", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/00725", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/085", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/00725", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 74568475