CN112399509B - User equipment, communication system and method for processing handoff failure of user equipment - Google Patents
User equipment, communication system and method for processing handoff failure of user equipment Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/16—Performing reselection for specific purposes
- H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
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Abstract
The invention provides user equipment, a communication system and a method for processing handoff failure. The handover procedure for the user equipment from the source cell to the configured target cell fails. In this method, a cell selection procedure to select a suitable cell is performed in response to a handover procedure failure. The cell selection procedure is configured to perform a connection re-establishment procedure. And judging whether to continue the connection reestablishment procedure according to the judging result of whether the proper cell is the configured target cell.
Description
Technical Field
The invention relates to user equipment, a communication system and a method for processing handoff failure of the user equipment.
Background
The handover failure procedure is used to detect a handover problem that a User Equipment (UE) cannot complete the handover procedure, wherein the handover problem can be detected by a timer. Fig. 1 is a flow chart of a known handoff procedure. Referring to fig. 1, after the ue 110 receives a handover command from the current serving cell (SERVING CELL) 120 (step S101), a timer T is started. If the ue 110 successfully hands over to the target cell (TARGET CELL) 130 (step S102), the ue 110 transmits a handoff completion message (step S103) to announce that the handoff procedure is completed, and the timer T will be stopped. However, when the timer T expires, if the user equipment 110 has not successfully sent the handoff completion message, a problem occurs that indicates that the handoff has failed. Upon a handoff failure, the user equipment 110 will trigger a connection re-establishment (re-establishment) procedure to re-establish the radio resource control (Radio Resource Control, RRC) connection.
It should be noted that, prior to preparing to perform the connection re-establishment procedure, the existing mechanism assumes that only the source cell 120 retains the context (context) data of the ue 110, so that the ue 110 needs to revert to the configuration of the source cell 120 (i.e., the source cell configuration) that was originally used by the source cell 120 for Radio Bearers (RBs), so that the identity of the ue 110 can be identified by the source cell 120 for the selected cell in the subsequent connection re-establishment procedure. Even though the target cell 130 may acquire context data of the ue 110 during the handover preparation phase, if the selected cell is still the target cell 130, the target cell 130 still needs to identify the identity of the ue 110 through the source cell 120. Obviously, such situations cause unnecessary delays.
It should be noted that in the application scenario of the fifth generation (5G) New Radio (NR), there is a relatively high chance that the ue 110 is still within the service coverage of the target cell 130 after the handover failure. That is, the cell selected by the user equipment 110 is still the target cell 130. Context one is that the movement trajectory or cell of the user equipment 110 is predictable: for example, the user device 110 is on a high-speed train or the user device 110 is in a non-terrestrial network (non-TERRESTRIAL NETWORK) context. Scenario two is a handoff failure caused by Listen-Before-Talk (LBT) failure: for example, the listen before talk failure in the case of New Radio-unlicensed spectrum access (New Radio-Unlicensed Spectrum Access, NR-U) and the user equipment 110 remains within the service coverage of the target cell 130 after the handoff failure. Scenario three is to configure multiple target cells 130 in a handoff procedure: for example, in conditional handover (conditional handover, CHO), the user equipment 110 may configure more than one target cell 130, and even if a handover failure occurs, the user equipment 110 has a relatively high chance to stay within service coverage of other configured target cells 130. It follows that there is a need to provide improved mechanisms to avoid program delays.
Disclosure of Invention
The embodiment of the invention aims at user equipment, a communication system and a method for processing handoff failure thereof.
According to the embodiment of the invention, the handling manner of the handover failure is suitable for the case that the handover procedure of the user equipment from the source cell to one or more configured target cells fails. This treatment method includes (but is not limited to) the following steps: in response to the handoff procedure failure, a cell selection procedure is performed to select a suitable cell. The cell selection procedure is configured to perform a connection re-establishment procedure. And judging whether to continue the connection reestablishment procedure according to the judging result of whether the proper cell is the configured target cell.
According to embodiments of the present invention, user equipment includes, but is not limited to, a receiver, a transmitter, and a processor. The receiver is used for receiving signals. The transmitter is used for transmitting signals. The processor is coupled to the receiver and the transmitter. The processor is configured to perform the steps of: in response to a failure of the handoff procedure from the source cell to one or more configured target cells, a cell selection procedure is performed to select a suitable cell. The cell selection procedure is configured to perform a connection re-establishment procedure. And judging whether to continue the connection reestablishment procedure according to the judging result that the proper cell is the configured target cell.
According to embodiments of the present invention, a communication system includes, but is not limited to, a source cell, one or more configured target cells, and a user equipment. The handover procedure for the user equipment from the source cell to the configured target cell fails. In response to the handover procedure failure, the user equipment performs a cell selection procedure to select a suitable cell. The cell selection procedure is configured to perform a connection re-establishment procedure. And judging whether to continue the connection establishment handoff procedure according to the judging result of whether the proper cell is the configured target cell.
It should be understood, however, that this summary may not contain all aspects and embodiments of the present disclosure, is not intended to be limiting or restrictive in any way, and that the invention as disclosed hereinabove and hereinafter is to be understood by those skilled in the art to encompass obvious improvements and modifications thereto.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIG. 1 is a flow chart of a conventional handoff procedure;
FIG. 2 is a block diagram of a communication system according to an embodiment of the present invention;
FIG. 3 is a flowchart of a handoff procedure according to an embodiment of the present invention;
FIG. 4 is a flowchart of a handoff failure processing procedure according to an embodiment of the present invention;
fig. 5 is a flowchart of a cell selection procedure according to an embodiment of the present invention;
FIG. 6 is a flow chart of a method for handling a handoff failure according to an embodiment of the present invention;
FIG. 7 is a flowchart of a continued handoff procedure according to an embodiment of the present invention;
FIG. 8 is a flowchart of a continued handoff procedure according to an embodiment of the present invention;
FIG. 9 is a flowchart of a continued handoff procedure according to an embodiment of the present invention;
FIG. 10 is a flowchart of a continued handoff procedure according to an embodiment of the present invention;
FIG. 11 is a flowchart of a continued handoff procedure according to an embodiment of the present invention;
FIG. 12 is a flow chart of a conditional handoff procedure according to an embodiment of the present invention;
FIG. 13 is a flowchart of a continuous connection reestablishment procedure according to one embodiment of the present invention.
Description of the reference numerals
110. 200, User equipment;
120, the current service cell;
130, target cell;
T is a timer;
S101～S103、S310～S360、S410～S430、S510～S540、S610～S650、S710～S750、S810～S850、S910～S950、S1010～S1050、S1110～S1150、S1210～S1230、S1310～S1340: A step of;
10, source cell;
30, a target cell;
A second target cell;
210 an antenna;
220 a receiver;
230, a conveyor;
analog to digital and digital to analog converters 240;
250, a memory;
260, a processor.
Detailed Description
Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.
Fig. 2 is a block diagram of a communication system 2 according to an embodiment of the invention. Referring to fig. 2, the communication system 2 includes, but is not limited to, a source cell 10, one or more target cells 30, a second target cell 50, and a user equipment 200.
Various implementations of the source cell 10, the target cell 30, and the second target cell 50 are possible, such as, but not limited to, a home evolved node B (Home Evolved Node B, heNB), an eNB, a next generation node B (gNB), an access and Backhaul integrated network (IAB) node, a advanced Base station (Advanced Base Station, ABS), a Base transceiver system (Base TRANSCEIVER SYSTEM, BTS), a repeater, a cell, and/or a satellite-based communication Base station.
The user equipment 200 may have various implementation aspects, such as, but not limited to, mobile stations, advanced mobile stations (Advanced Mobile Station, AMS), telephony devices, customer premise equipment (Customer Premise Equipment, CPE), and wireless sensors.
User equipment 200 includes, but is not limited to, an antenna 210, a receiver 220, a transmitter 230, an analog-to-digital and digital-to-analog converter 240, a memory 250, and a processor 260. The antenna 210 is coupled to the receiver 220 and the transmitter 230. The analog-to-digital and digital-to-analog converter 240 is coupled to the receiver 220, the transmitter 230 and the processor 260. The processor 260 is further coupled to the memory 250.
The receiver 220 and the transmitter 230 are configured to wirelessly receive a downlink (downlink) signal and transmit an uplink (uplink) signal, respectively, via the antenna 210. The receiver 220 and the transmitter 230 may also perform analog signal processing operations such as low noise amplification, impedance matching, mixing, up-or down-conversion, filtering, amplification, and the like. The analog-to-digital and digital-to-analog converter 240 is configured to convert from an analog signal format to a digital signal format during downlink signal processing and from a digital signal format to an analog signal format during uplink signal processing.
The Memory 250 may be any type of fixed or removable random access Memory (Random Access Memory, RAM), read-Only Memory (ROM), flash Memory (Flash Memory), or the like, or a combination of the above. The memory 250 records program codes, device configurations, codebooks (codebooks), buffered or permanent data, and records various communication protocol related software modules such as a radio resource Control (Radio Resource Control, RRC) layer, a packet data convergence communication protocol (PACKET DATA Convergence Protocol, PDCP) layer, radio connection Control (Radio Link Control, RLC), medium access Control (MEDIA ACCESS Control, MAC) layer, and data thereof.
The processor 260 is configured to process digital signals and execute programs according to exemplary embodiments of the present invention, and may access or load data and software modules recorded by the memory 250. The functions of the processor 260 may be implemented using programmable units such as a central Processing unit (Central Processing Unit, CPU), microprocessor, microcontroller, digital Signal Processing (DSP) chip, field programmable gate array (Field Programmable GATE ARRAY, FPGA), etc. The functions of the processor 260 may also be implemented in a stand-alone electronic device or integrated circuit (INTEGRATED CIRCUIT, IC), and the operations of the processor 260 may also be implemented in software.
Hereinafter, the method according to the embodiment of the present invention will be described with respect to each device and its components in the communication system 1. The flow of the method according to the embodiment of the present invention may be adjusted according to the implementation situation, and is not limited thereto.
Fig. 3 is a flowchart of a handoff procedure according to an embodiment of the present invention. Referring to fig. 3, the processor 260 of the ue 200 receives a radio resource control reconfiguration (RRC reconfiguration) message accompanied by a handover command (step S310) through the receiver 220 to trigger the initiation of the handover procedure. For convenience of description, it is assumed hereinafter that the ue 200 accepts the service of the source cell 10 (i.e., the source cell 10 is the currently serving cell or the current serving cell), and in response to the handoff condition (e.g., regarding signal strength, or the number of failures, etc.) being met, it is expected that the handoff (handoff) from the source cell 10 to the target cell 30 (e.g., the received signal strength of the target cell 30 is greater than that of the source cell 10 and the second target cell 50) (the target cell 30 may be referred to as a target base station). That is, the handoff procedure triggered at this time is for the access service to be handed off to the target cell 30. With the handoff procedure triggered, a timer (e.g., T304 or other timer defined by 3 GPP) will be started and used to detect if a handoff problem (handoff failure) has occurred.
The processor 260 may be configured using the configuration in the handoff instruction. The configuration (also referred to as source cell configuration) is the configuration provided by the source cell 10 and related to the target cell 30 to be handed over (step S320), and is accordingly handed over to the target cell 30. The processor 260 may transmit a reconfiguration complete (reconfiguration complete) message on the RRC connection to the target cell 30 through the transmitter 230 (step S330).
The processor 260 may determine whether the transmission of the reconfiguration complete signal was successful before the expiration of the aforementioned timer (step S340). I.e. to confirm whether the reconfiguration complete signal was successfully delivered to the target cell 30. If the reconfiguration complete signal is successfully sent, the handover procedure to the target cell 30 is completed (step S350). However, if the handover is not successfully delivered, the processor 260 further executes a handover failure procedure and declares that the handover procedure for handover to the target cell 30 has failed (step S360).
FIG. 4 is a flowchart of a handoff failure processing procedure according to an embodiment of the present invention. Referring to fig. 4, the processor 260 may release the dedicated preamble (DEDICATED PREAMBLE) for the handoff completion message (step S410). It should be noted that, unlike the configuration information provided by the prior art return source cell 10, the processor 260 of the embodiment of the present invention directly performs the connection reestablishment procedure for the handover failure (step S430). That is, the user equipment 200 does not immediately return the configuration information provided by the source cell 10, and needs to further evaluate whether to return the configuration information. Notably, this configuration is a state variable and parameter related to one or more Radio Bearers (RBs) used by the user equipment 200 and is used to let the target cell 30 or the second target cell 50 recognize the identity of the user equipment 200 through the source cell 10, and is for example "the configuration" (configuration) defined by 3gpp TS 38.331 regarding a handover failure due to T304.
Fig. 5 is a flowchart of a cell selection procedure according to an embodiment of the present invention. Referring to fig. 5, in the connection re-establishment procedure, the processor 260 performs cell selection (step S510) to select a suitable cell (e.g., a cell that the ue 200 can access (camp on) to obtain normal service, or "useable cell") for the connection re-establishment procedure during a specific time period. The processor 260 may determine whether a suitable cell has been selected for cell selection (step S520). If the time period expires without a suitable cell, the ue 200 enters idle mode (step S530). If there is a suitable cell (hereinafter referred to as the selected cell), the processor 260 continues the connection re-establishment procedure (step S540).
FIG. 6 is a flow chart of a method for handling a handoff failure according to an embodiment of the present invention. Referring to fig. 6, unlike the prior art, which directly transmits a request message for reestablishing the RRC connection to the selected cell based on the configuration provided by the source cell 10, the embodiment of the present invention determines whether the selected cell (i.e., the selected suitable base station or the selected suitable cell) is the target cell 30 (i.e., the target cell for which handover is expected in the handover procedure) in the connection reestablishment procedure (step S610). For example, it is confirmed whether the identification information of the selected cell matches the identification information of the target cell 30.
In some embodiments, the source cell 10 may configure more than one target cell 30 to the user equipment 200 during the handoff procedure. The processor 260 may determine whether the selected cell is one of the configured target cells.
Next, the processor 260 determines to continue the handover procedure of the target cell 30 according to the determination result of the selected cell (i.e., whether the selected cell is the target cell 30 or not the target cell 30). On the other hand, this determination is also used to confirm whether to reuse the configuration provided by the source cell 10 to continue the connection re-establishment procedure for the selected cell.
If the selected cell is the target cell 30 (indicating that the ue 200 is still within the service coverage of the target cell 30), the processor 260 may transmit a connection request message to the target cell 30 through the transmitter 230 to continue the handover procedure of the target cell 30 (step S630).
In an embodiment, the connection request message may be associated with first user identification information of the user equipment 200 provided by the target cell 30 (e.g., entrained in the handover command received in the handover procedure) and cell identification information of the target cell 30. The first user identification information is, for example, a cell radio network temporary identity (Cell Radio Network Temporary Identifier, C-RNTI) or other identification information for identifying the user equipment 200. The cell identification information is, for example, a physical cell identifier (PHYSICAL CELL IDENTITY, PCI), or other cell identifier (cell ID).
Unlike the connection re-establishment message including the related information of the source cell 10 so as to identify the identity of the ue 200 through the source cell 10, the embodiment of the present invention can directly provide the related information of the target cell 30, so that the target cell 30 can identify the identity of the ue 200 by itself/locally.
In some embodiments, the connection request message may further include the second user identification information provided by the source cell 10 and the cell identification information of the source cell 10 in addition to the first user identification information and the cell identification information of the target cell, so that the target cell 30 requests the identity of the ue 200 from the source cell 10 (i.e., to the outside). The second subscriber identity information and the cell identity information of the source cell 10 may refer to the first subscriber identity information and the cell identity information of the target cell 30, respectively, and will not be described herein.
On the other hand, if the selected cell is the target cell 30, the processor 260 may not continue using the configuration provided by the source cell 10 and may not need or cancel sending the connection re-establishment request message to continue the connection re-establishment procedure.
FIG. 7 is a flowchart of a continued handoff procedure according to an embodiment of the present invention. Referring to fig. 7, in response to the sending of the connection request message, the processor 260 determines whether the receiver 220 receives the connection response (step S710). The connection response is for responding to the connection request message and is related to the success of the handoff procedure. For example, the target cell 30 has obtained context data of the ue 200 according to the connection request message. That is, the target cell 30 has confirmed the identity of the user equipment 200. The context data is necessary information for maintaining the access service of the user equipment 200. Such as status, security, capability, and/or link identification information.
If a connection response has been received, the processor 260 may transmit a connection completion message to the target cell 30 through the transmitter 230 (step S720). The connection complete message may be used to indicate that the connection re-establishment procedure is completed or that the handover procedure to the target cell 30 is completed.
On the other hand, if no connection response is received, the processor 260 further determines whether the receiver 220 receives a connection setup message (setup) related to RRC connection (step S730). This connection setup message is related to the target cell 30 not taking the context data of the user equipment 200 or not recognizing the identity of the user equipment 200. If the connection setup message is not received, the processor 260 enters an idle mode (step S740). That is, the user equipment 200 cancels the handover to the target cell 30. On the other hand, if a connection setup message is received, the processor 260 will establish a new connection (e.g., a new RRC connection, or a new signaling radio bearer (SIGNALING RADIO BEARER, SRB)) for the target cell 30 in accordance with the connection setup message (step S750).
The following examples illustrate how to continue the handoff procedure for the target cell 30. Further, it is assumed that the user equipment 20 has confirmed that the selected cell has met the conditions of the suitable target cell and that the selected cell is the target cell 30, and generally speaking meets the conditions of the continued handover procedure.
FIG. 8 is a flowchart of a continued handoff procedure according to an embodiment of the present invention. Referring to fig. 8, if the ue 200 accords with the continuous handover procedure, a connection request message is transmitted to the target cell 30 (step S810). In this embodiment, the connection request message includes the cell identification information of the target cell 30 and the first user identification information of the user equipment 200 provided thereby. The target cell 30 recognizes and verifies the identity of the ue 200 according to the cell identification information and the first subscriber identification information, and locally searches for corresponding context data (step S820). Local search here refers to not recognizing identity by the source cell 10 or confirming whether itself still retains context data. If the target cell 30 obtains the context data (step S830), a connection response is sent to the ue 200 (step S840). And the ue 200 may transmit a connection completion message to the target cell 30 based on the receipt of the connection response (step S850).
FIG. 9 is a flowchart of a continued handoff procedure according to an embodiment of the present invention. Referring to fig. 9, steps S910 and S920 may refer to the descriptions of steps S810 and S820 of fig. 8, respectively, and are not described herein. The difference from the embodiment of fig. 8 is that the target cell 30 fails to acquire or retain the context data of the user equipment 20 (step S930). In addition, the target cell 30 transmits a connection setup message to the ue 200 (step S940), so that the ue 200 can establish a new connection (step S950).
FIG. 10 is a flowchart of a continued handoff procedure according to an embodiment of the present invention. Referring to fig. 10, the difference between the embodiments of fig. 8 and 9 is that the connection request message further includes the cell identification information of the source cell 10 and the second subscriber identification information of the ue 200 provided by the source cell 10 (step S1010). At this time, even if the target cell 30 does not retain the context data of the ue 200, the identity of the ue 200 is identified (i.e. the context data is found locally or externally) by the source cell 10 according to the cell identification information of the source cell 10 and the second subscriber identification information, and the context data is obtained accordingly (step S920). The steps S1040 and S1050 can refer to the descriptions of the steps S840 and S850 of fig. 8, respectively, and are not repeated here. In some embodiments, the connection response transmitted in step S1040 may instruct the ue 200 to return to the configuration provided by the source target cell 10.
FIG. 11 is a flowchart of a continued handoff procedure according to an embodiment of the present invention. Referring to fig. 11, steps S1110 and S1120 can be respectively described with reference to steps S1010 and S1020 of fig. 10, and are not described herein. The difference from the embodiment of fig. 10 is that the source cell 10 and the target cell 30 both have no context data reserved, so that the target cell 30 cannot acquire the context data (step S1130). Next, steps S1140 and S1150 in fig. 11 can refer to steps S940 and S950 in fig. 9, respectively, and are not described herein.
FIG. 12 is a flow chart of a Conditional Handoff (CHO) procedure according to one embodiment of the present invention. Referring to fig. 12, assume that the ue 20 sets a conditional handoff configuration (CHO configuration). The ue 20 declares a handoff failure (step S1210), and further determines whether the conditional handoff is met for the connection re-establishment procedure (step S1220). This condition may include the target cell candidate for the selected cell (i.e., target cell 30) meeting the conditions of the appropriate cell and being a set conditional handoff configuration. If the condition is met, the ue 20 may further transmit a handover complete message to indicate that the handover procedure of the target cell 30 is completed (step S1230).
The foregoing embodiments are related to the case where the selected cell is the target cell 30. Returning to fig. 6, if the selected cell is not the target cell 30 (assuming that the selected cell is the second target cell 50 of fig. 2), the processor 260 continues the connection re-establishment procedure of the selected cell according to the configuration provided by the source cell 10 and transmits a connection re-establishment request message to the second target cell 50 through the transmitter 230 (step S650). In contrast to the prior art that returns to the configuration provided by the source cell 10 prior to the cell selection procedure, the present embodiment changes to determine whether to return to the configuration based on the determination of the selected cell (i.e., the point in time is after the cell selection procedure). The connection re-establishment request message will provide information of the ue 200 (e.g. the cell identification information of the source cell 10 and the second subscriber identification information provided by the source cell 10) for the second target cell 50 to recognize the identity of the ue 200 through the source cell 10 and obtain the context data of the ue according to the information.
FIG. 13 is a flowchart of a continuous connection reestablishment procedure according to one embodiment of the present invention. Referring to fig. 13, the processor 260 receives a connection reestablishment response through the receiver 220 (step S1310). The connection re-establishment response is in response to the connection re-establishment request message and is in relation to the second target cell 50 having successfully acquired the context data. In some embodiments, if the connection re-establishment procedure can be continued, the second target cell 50 can perform the reconfiguration procedure related to the RRC connection, so that the receiver 220 receives the corresponding reconfiguration message (step S1320).
Next, in response to receipt of the connection re-establishment response, the processor 260 may transmit a completion message through the transmitter 230 (step 1330). In addition, in response to receipt of the reconfiguration message, the processor 260 may transmit a wire reconfiguration complete message via the transmitter 230 (step 1340). Thus, the connection re-establishment procedure and the reconfiguration procedure may be completed, i.e. it is indicated that the ue 200 has successfully re-established the connection with the second target cell 50.
In summary, in the ue, the communication system, and the method for handling a handover failure according to the embodiments of the present invention, it is determined whether the selected cell obtained by the cell selection procedure is a target cell of the original handover procedure (e.g., whether the ue is still within the service coverage of the target cell), and whether to continue the handover procedure with the target cell is determined based on the determination result. Compared with the prior art, if the selected cell is still the original target cell, the connection reestablishment procedure can be simplified, thereby reducing signaling waste and further avoiding program delay.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (18)
1. A method of handling a handover failure, wherein a handover procedure for a user equipment from a source cell to at least one configured target cell fails, the method comprising:
in response to a handoff procedure failure of the user equipment from a source cell to at least one configured target cell, performing a cell selection procedure to select a suitable cell, wherein the cell selection procedure is configured to perform a connection re-establishment procedure;
determining, by the user equipment, whether the suitable cell selected by the cell selection procedure is the at least one configured target cell, to obtain a determination result; and
Judging whether to continue the connection reestablishment program according to the judging result, including:
And in response to the judgment result that the suitable cell is the at least one configured target cell, transmitting a connection request message to the suitable cell so as to continue the handoff procedure.
2. The method of claim 1, wherein the step of reestablishing the connection further comprises:
and in response to the judgment result that the suitable cell is not the at least one configured target cell, transmitting a connection re-establishment request message to the suitable cell and recovering to the source cell configuration.
3. The method of claim 2, wherein the connection request message is associated with first user identification information and cell identification information of the at least one configured target cell, and wherein the first user identification information is provided by the at least one configured target cell.
4. The method of claim 3, wherein the connection request message further includes second user identification information and cell identification information of the source cell, and wherein the second user identification information is provided by the source cell.
5. The method of claim 2, further comprising, after the step of transmitting the connection request message:
receiving a connection response, wherein the connection response is related to the handoff procedure having been successful; and
And transmitting a completion message in response to receiving the connection response, wherein the completion message is used for indicating that the handoff procedure is completed.
6. The method of claim 4, further comprising, after the step of transmitting the connection request message:
and receiving a connection setting message, wherein the connection setting message is used for establishing a new connection.
7. The method of handling a handoff failure according to claim 1, further comprising:
judging that the hand-off program accords with the conditional hand-off; and
In response to the conditional handoff failure, performing the cell selection procedure to select the suitable cell;
Judging whether to continue the connection reestablishment procedure according to the judging result of whether the suitable cell is the at least one configured target cell, wherein the at least one configured target cell is configured by the conditional handoff; and
And in response to the judgment result that the suitable cell is the at least one configured target cell, transmitting a handoff completion message to the suitable cell so as to continue the handoff procedure.
8. The method of claim 1, wherein prior to the step of determining whether the suitable cell is the at least one configured target cell, further comprising:
cancelling transmission of a handoff completion message, wherein the handoff completion message is used for indicating completion of the handoff procedure; and
And executing the connection reestablishment program and suspending the use of the source cell configuration.
9. A user device, comprising:
A receiver for receiving a signal;
a transmitter for transmitting a signal; and
A processor coupled to the receiver and the transmitter and configured to:
In response to a handoff procedure failure from a source cell to at least one configured target cell, performing a cell selection procedure to select a suitable cell, wherein the cell selection procedure is configured to perform a connection re-establishment procedure;
Obtaining a judgment result by determining whether the suitable cell selected by the cell selection procedure is the at least one configured target cell; and
Judging whether to continue the connection reestablishment program according to the judging result, including:
And in response to the judgment result that the suitable cell is the at least one configured target cell, transmitting a connection request message to the suitable cell so as to continue the handoff procedure.
10. The user equipment of claim 9, wherein the processor is configured to further:
And in response to the determination that the suitable cell is not the at least one configured target cell, transmitting a connection re-establishment request message to the suitable cell through the transmitter and restoring to a source cell configuration.
11. The user equipment of claim 10, wherein the processor is configured to:
Receiving a connection response by the receiver, wherein the connection response is associated with the handoff procedure having been successful; and
And transmitting a completion message by the transmitter in response to receiving the connection response, wherein the completion message is used for indicating that the handoff procedure is completed.
12. The user equipment of claim 10, wherein the processor is configured to:
and receiving a connection setting message by the receiver, wherein the connection setting message is related to establish a new connection.
13. The user equipment of claim 9, wherein the processor is configured to:
judging that the hand-off program accords with the conditional hand-off condition; and
In response to the conditional handoff failure, performing the cell selection procedure to select the suitable cell;
Judging whether to continue the connection reestablishment procedure according to the judging result of whether the suitable cell is the at least one configured target cell, wherein the at least one configured target cell is configured by the conditional handoff; and
And in response to the judgment result that the suitable cell is the at least one configured target cell, transmitting a handoff completion message to the suitable cell through the transmitter so as to continue the handoff procedure.
14. The user equipment of claim 9, wherein the processor is configured to:
cancelling transmission of a handoff completion message, wherein the handoff completion message is used for indicating completion of the handoff procedure; and
And executing the connection reestablishment program and suspending the use of the source cell configuration.
15. A communication system, comprising:
a source cell;
at least one configured target cell; and
A user equipment, wherein a handoff procedure of the user equipment from the source cell to the at least one configured target cell fails,
In response to a handoff procedure failure of the user equipment from a source cell to at least one configured target cell, the user equipment performs a cell selection procedure to select a suitable cell, wherein the cell selection procedure is configured to perform a connection re-establishment procedure;
determining, by the user equipment, whether the suitable cell selected by the cell selection procedure is the at least one configured target cell, to obtain a determination result; and
Judging whether to continue the connection reestablishment program according to the judging result, including:
And in response to the judgment result that the suitable cell is the at least one configured target cell, transmitting a connection request message to the suitable cell so as to continue the handoff procedure.
16. The communication system of claim 15, wherein in response to the determination that the suitable cell is not the at least one configured target cell, the user equipment transmits a connection re-establishment request message to the suitable cell and reverts to a source cell configuration.
17. The communication system of claim 15, wherein the wire request message is associated with first user identification information and cell identification information of the at least one configured target cell, and wherein the first user identification information is provided by the at least one configured target cell.
18. The communication system of claim 17, wherein the connection request message further includes second subscriber identification information and cell identification information of the source cell, and wherein the second subscriber identification information is provided by the source cell.
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| US201962887680P | 2019-08-16 | 2019-08-16 | |
| US62/887,680 | 2019-08-16 | ||
| US16/984,003 US11470532B2 (en) | 2019-08-16 | 2020-08-03 | User equipment, communication system, and handling method for handover failure |
| US16/984,003 | 2020-08-03 | ||
| TW109126545 | 2020-08-05 | ||
| TW109126545A TWI790464B (en) | 2019-08-16 | 2020-08-05 | User equipment, communication system, and handling method for handover failure |
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