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WO2018123025A1 - Station de base, terminal, système de communication, et procédé de communication - Google Patents

Station de base, terminal, système de communication, et procédé de communication Download PDF

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Publication number
WO2018123025A1
WO2018123025A1 PCT/JP2016/089115 JP2016089115W WO2018123025A1 WO 2018123025 A1 WO2018123025 A1 WO 2018123025A1 JP 2016089115 W JP2016089115 W JP 2016089115W WO 2018123025 A1 WO2018123025 A1 WO 2018123025A1
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WO
WIPO (PCT)
Prior art keywords
terminal
cell
handover method
base station
value
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Ceased
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PCT/JP2016/089115
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English (en)
Japanese (ja)
Inventor
哲哉 長谷川
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Fujitsu Ltd
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Fujitsu Ltd
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Priority to PCT/JP2016/089115 priority Critical patent/WO2018123025A1/fr
Publication of WO2018123025A1 publication Critical patent/WO2018123025A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements

Definitions

  • 3GPP Third generation mobile communication system
  • LTE Long Term Evolution
  • 5G fifth generation mobile communication system
  • RACH Random Access Channel
  • an object of the present invention is to provide a base station, a terminal, a communication system, and a communication method that can reduce the time required for handover.
  • a terminal transmits a radio signal of its own terminal and a reference timing of a second cell different from the first cell to which the terminal is connected.
  • a first handover method in which the base station of the first cell includes a random access procedure, and a second handover that does not include at least a part of the random access procedure.
  • the terminal may include a first handover method that includes a random access procedure and a second handover method that does not include at least a part of the random access procedure. Transmitting information indicating a handover method selected based on a value indicating a shift amount between a transmission timing and a reference timing of a second cell different from the first cell to which the terminal is connected; A base station, a terminal, a communication system, and a communication method are proposed in which the base station performs control to switch the connection destination of the terminal to the second cell by the handover method indicated by the information transmitted by the terminal.
  • the present invention has the effect of reducing the time required for handover.
  • FIG. 1 is a diagram illustrating an example of a communication system according to an embodiment.
  • FIG. 2 is a sequence diagram illustrating an example of processing when the UE selects the HO method in the communication system according to the embodiment.
  • FIG. 3 is a sequence diagram illustrating another example of processing when the UE selects the HO method in the communication system according to the embodiment.
  • FIG. 4 is a sequence diagram illustrating an example of processing when the source eNB selects the HO method in the communication system according to the embodiment.
  • FIG. 5 is a sequence diagram illustrating another example of processing when the source eNB selects the HO method in the communication system according to the embodiment.
  • FIG. 6 is a flowchart illustrating an example of processing performed by the UE according to the embodiment.
  • FIG. 7 is a flowchart illustrating an example of setting processing by the source base station according to the embodiment.
  • FIG. 8 is a flowchart illustrating an example of the HO process performed by the source eNB according to the embodiment.
  • FIG. 9 is a diagram illustrating an example of the UE according to the embodiment.
  • FIG. 10 is a diagram illustrating an example of a hardware configuration of the UE according to the embodiment.
  • FIG. 11 is a diagram illustrating an example of the eNB according to the embodiment.
  • FIG. 12 is a diagram illustrating an example of a hardware configuration of the eNB according to the embodiment.
  • FIG. 13 is a diagram illustrating an example of an event type definition according to the embodiment.
  • FIG. 14 is a diagram illustrating an example of a measurement report according to the embodiment.
  • FIG. 15 is a sequence diagram illustrating an example of a UE capability inquiry procedure in the communication system according to the embodiment.
  • FIG. 16 is a sequence diagram illustrating an example of calculating the
  • FIG. 1 is a diagram illustrating an example of a communication system according to an embodiment.
  • the communication system 100 includes a terminal 110 and a first base station 120.
  • the communication system 100 may further include a second base station 130.
  • the first base station 120 is a base station apparatus that forms a first cell and can perform wireless communication with the terminal 110 using the first cell.
  • the second base station 130 is a base station apparatus that forms a second cell different from the first cell and can perform wireless communication with the terminal 110 using the second cell.
  • Each of the 1st base station 120 and the 2nd base station 130 is eNB (evolved Node B) as an example.
  • eNB evolved Node B
  • the terminal 110 includes a calculation unit 111, a transmission unit 112, and a control unit 113.
  • the calculation unit 111 calculates a value indicating a deviation amount (a magnitude of deviation) between the transmission timing of the radio signal of the terminal (terminal 110) and the reference timing of the second cell, and calculates the calculated TA value.
  • the data is output to the transmission unit 112.
  • the value indicating the amount of deviation is, for example, a TA value.
  • TA is an abbreviation for Timing Advance.
  • the calculation unit 111 calculates the TA value based on the reference signal transmitted by the second cell of the second base station 130. The calculation of the TA value will be described later.
  • the transmission timing of the radio signal of the terminal 110 to the second cell of the second base station 130 is determined by the terminal 110. Is a timing for transmitting a radio signal to the second cell.
  • the reference timing of the second cell serving as a reference for the TA value is a timing for performing a reception process of a radio signal from the terminal 110 in the second cell of the second base station 130.
  • the transmission unit 112 wirelessly transmits a value indicating the amount of deviation output from the calculation unit 111 to the first base station 120 of the first cell. For example, the transmission unit 112 wirelessly transmits a value indicating the amount of deviation output from the calculation unit 111 to the first base station 120 together with the measurement result of the wireless quality in each terminal 110 of the first cell and the second cell. However, the transmission unit 112 may wirelessly transmit a value indicating the amount of deviation to the first base station 120 at an opportunity different from the transmission of the wireless quality measurement result.
  • the control unit 122 based on the value indicating the amount of deviation output from the reception unit 121, a first handover method including a random access procedure, a second handover method not including at least a part of the random access procedure, Select one of the following. Then, the control unit 122 performs control to switch the connection destination of the terminal 110 from the first cell of the first base station 120 to the second cell of the second base station 130 by the selected handover method.
  • control unit 122 determines whether to perform a handover for switching the connection destination of the terminal 110 to the second cell based on the measurement result of the radio quality output from the reception unit 121. Then, when the control unit 122 determines to perform handover for switching the connection destination of the terminal 110 to the second cell, the control unit 122 performs the handover method selected based on the value indicating the amount of deviation output from the reception unit 121 by the handover method. Control to switch the connection destination to the second cell is performed.
  • the random access procedure is a random access procedure executed between the terminal 110 and the second base station 130.
  • the random access procedure is a procedure in which the terminal 110 connects to the second base station 130 by transmitting and receiving radio signals between the terminal 110 and the second base station 130 using RACH.
  • the first handover method including a random access procedure is a handover in which the connection destination of the terminal 110 is switched to the second cell of the second base station 130 by executing the random access procedure between the terminal 110 and the second base station 130, for example. It is a method.
  • the second handover method that does not include at least a part of the random access procedure is, for example, a handover method that does not include a procedure for adjusting transmission timing from the terminal 110 to the second base station 130 among the random access procedures. is there.
  • the second handover method is a handover method in which the connection destination of the terminal 110 is switched to the second cell of the second base station 130 without executing a random access procedure between the terminal 110 and the second base station 130. is there. That is, the second handover method is a handover that does not use RACH, for example.
  • the second handover method is a RACH-less (RACH-less) handover in 3GPP TR 36.881 or the like.
  • control unit 122 selects the second handover method when the amount of deviation indicated by the value output from the receiving unit 121 is equal to or less than a predetermined amount.
  • the second handover method is used. A handover can be performed. For this reason, the time taken for the handover can be shortened.
  • control unit 122 selects the first handover method when the amount of deviation indicated by the value output from the receiving unit 121 is greater than a predetermined amount.
  • the first handover method is used. A handover can be performed. For this reason, failure of the handover can be suppressed and the time taken for the handover can be shortened.
  • the terminal 110 transmits a radio signal including a CP (Cyclic Prefix) when it is connected to the second cell to the second cell
  • the above-described predetermined amount compared with the amount of deviation is It can be an amount based on length (eg, CP length).
  • the radio signal including the CP is, for example, an OFDM (Orthogonal Frequency Division Multiplexing) signal.
  • the first handover method including the random access procedure and at least a part of the random access procedure are performed based on the amount of deviation between the radio signal transmission timing of the terminal 110 and the reference timing of the second cell.
  • the second handover method not included is switched. Thereby, the time taken for the handover can be shortened.
  • the receiving unit 121 receives information indicating the handover method transmitted from the terminal 110, and outputs the received information to the control unit 122.
  • the reception unit 121 may receive information indicating the handover method together with the measurement result of the radio quality from the terminal 110, and output the received measurement result of the radio quality and information indicating the handover method to the control unit 122.
  • the terminal 110 may be configured to select the handover method. Also in this case, the time required for the handover can be shortened as in the configuration in which the handover method is selected in the first base station 120.
  • the first selection method in which the handover method is selected in the first base station 120 and the second selection method in which the handover method is selected in the terminal 110 may be switchable.
  • the first base station 120 selects which of the first selection method and the second selection method is performed, and transmits information indicating the selected selection method to the terminal 110.
  • the terminal 110 performs processing according to the selection method indicated by the information transmitted from the first base station 120.
  • the terminal 110 may select which of the first selection method and the second selection method is performed, and information indicating the selected selection method may be transmitted to the first base station 120.
  • the first base station 120 performs processing according to the selection method indicated by the information transmitted from the terminal 110.
  • the second cell is a cell formed by the second base station 130 different from the first base station 120
  • the second cell is a cell formed by the first base station 120. It's okay. That is, the terminal 110 may be handed over from the first cell of the first base station 120 to the second cell of the first base station 120.
  • FIG. 2 is a sequence diagram illustrating an example of processing when the UE selects the HO method in the communication system according to the embodiment.
  • the terminal 110 illustrated in FIG. 1 can be realized by, for example, the UE 210 illustrated in FIG.
  • the first base station 120 illustrated in FIG. 2 can be realized by the source eNB 220 illustrated in FIG. 2, for example.
  • the second base station 130 illustrated in FIG. 2 can be realized by the target eNB 230 illustrated in FIG. 2, for example.
  • each step shown in FIG. 2 is executed.
  • the source eNB 220 sets “Event Y” in which the UE 210 selects the HO (handover) method of the UE 210 to the UE 210 as the event type (EventType) will be described.
  • the source eNB 220 transmits an RRC reconfiguration (RRC Reconfiguration) designating “Event Y” as an event type to the UE 210 (step S201).
  • RRC is an abbreviation for Radio Resource Control (Radio Resource Control).
  • UE210 transmits RRC reconfiguration complete (RRC Reconf comp) with respect to RRC reconfiguration transmitted by step S201 to the source eNB220 (step S202).
  • Legacy HO is HO (first handover method) using, for example, a RACH procedure (for example, transmission / reception of MSG1 to MSG4).
  • a RACH procedure for example, transmission / reception of MSG1 to MSG4.
  • the length of the CP of the OFDM signal transmitted from the UE 210 to the target eNB 230 can be used as the threshold to be compared with the amount of deviation.
  • the UE 210 transmits to the source eNB 220 a measurement report that includes the RACH less flag set to “on” and indicates the measurement result of the radio quality (step S207).
  • the RACH less flag is flag information indicating that a RACH less HO is requested when “on” and a legacy HO is requested when “off”.
  • the measurement result of the radio quality is a measurement result of the radio quality in the UE 210 for each cell of the source eNB 220 and the target eNB 230, for example.
  • the radio quality is radio quality such as RSRP or RSRQ.
  • RSRP is an abbreviation for Reference Signal Received Power (reference signal received power).
  • RSRQ is an abbreviation for Reference Signal Received Quality (reference signal reception quality).
  • the source eNB 220 determines handover for switching the connection destination of the UE 210 from the source eNB 220 to the target eNB 230 based on the measurement result of the radio quality indicated by the measurement report received from the UE 210.
  • the source eNB 220 transmits a handover request (Handover Request) requesting RACH-less HO to the target eNB 230 (step S208).
  • FIG. 3 is a sequence diagram illustrating another example of processing when the UE selects the HO method in the communication system according to the embodiment.
  • each step shown in FIG. 3 is executed.
  • the source eNB 220 sets “Event Y” in which the UE 210 selects the HO method of the UE 210 as the event type in the UE 210 will be described.
  • Steps S301 to S308 shown in FIG. 3 are the same as steps S201 to S208 shown in FIG. However, in the example illustrated in FIG. 3, it is assumed that the UE 210 selects the legacy HO in step S306. As an example, when the distance between the source eNB 220 and the target eNB 230 is long, the TA value calculated in step S305 becomes larger than the threshold, and the UE 210 selects the legacy HO.
  • the UE 210 can connect to the target eNB 230 by the RACH procedure in step S311.
  • UE210 transmits RRC reconfiguration complete to target eNB230 (step S312).
  • step S312 HO which switches the connection destination of UE210 from the cell of the source eNB220 to the cell of the target eNB230 is completed. That is, in the example illustrated in FIG. 3, the UE 210 can perform HO without omitting the RACH procedure.
  • MSG1 (first message) is, for example, a random access preamble from the UE 210 to the target eNB 230 (Random Access Preamble).
  • the target eNB 230 assigns C-RNTI based on MSG1 from the UE 210, determines transmission timing in the UE 210, and assigns uplink resources.
  • C-RNTI is an abbreviation for Cell-Radio Network Temporary Identifier.
  • MSG2 (second message) is, for example, a random access response (Random Access Response) from the target eNB 230 to the UE 210.
  • the random access response includes, for example, UL grant (uplink transmission permission), transmission timing (Timing Alignment information), CQI (Channel Quality Indicator) request, and the like.
  • MSG4 (fourth message) is, for example, contention resolution.
  • the contention resolution is, for example, a response signal (Ack) from the target eNB 230 to the UE 210 for MSG3.
  • FIG. 4 is a sequence diagram illustrating an example of processing when the source eNB selects the HO method in the communication system according to the embodiment.
  • each step shown in FIG. 4 is executed.
  • FIG. 4 a case where the source eNB 220 sets “Event X” in which the source eNB 220 selects the HO method of the UE 210 as the event type in the UE 210 will be described.
  • the target eNB 230 selects a HO method performed by the UE 210 based on the TA value included in the measurement report received in step S406 (step S407).
  • the selection of the HO method by the target eNB 230 is the same as the selection of the HO method by the UE 210 described in step S206 of FIG. In the example illustrated in FIG. 4, it is assumed that the target eNB 230 has selected RACH-less HO.
  • Steps S408 to S411 shown in FIG. 4 are the same as steps S208 to S211 shown in FIG.
  • the source eNB 220 transmits an RRC reconfiguration specifying “Event X” as the event type to the UE 210 (step S501).
  • Steps S502 to S505 shown in FIG. 5 are the same as steps S302 to S305 shown in FIG.
  • the UE 210 transmits a measurement report including the TA value calculated in step S505 and indicating the measurement result of the radio quality to the source eNB 220 (step S506).
  • FIG. 6 is a flowchart illustrating an example of processing performed by the UE according to the embodiment.
  • UE210 concerning embodiment performs each step shown, for example in FIG.
  • UE210 sets the measurement cell and measurement item of an own terminal (step S601).
  • the measurement cell of the own terminal includes the cell of the source eNB 220 and the cell of the target eNB 230 to which the UE 210 is connected.
  • the measurement items include, for example, radio quality and TA value.
  • the radio quality includes, for example, RSRP or RSRQ.
  • step S603 when the report condition is not satisfied (step S603: No), the UE 210 returns to step S602.
  • step S603: Yes the UE 210 determines whether or not “Event X” is set as the event type for the own terminal (step S604). The determination in step S604 can be made based on the event type specified in the RRC reconfiguration received by the UE 210 from the source eNB 220, for example.
  • the UE 210 transmits a report signal including the TA value calculated in step S605 to the source eNB 220 (step S606), and returns to step S602.
  • the report signal is, for example, the above-described measurement report.
  • the report signal may include information indicating the event type set in the UE 210.
  • step S604 when both “Event X” and “Event Y” are set as the event type in the own terminal, UE 210 reports both the TA value and the selected HO method to source eNB 220. May be. In this case, for example, the UE 210 calculates a TA value, selects a HO method based on the calculated TA value, and outputs a report signal including the RACH less flag corresponding to the selected method and the calculated TA value. Transmit to source eNB 220.
  • FIG. 7 is a flowchart illustrating an example of setting processing by the source base station according to the embodiment.
  • the source eNB 220 according to the embodiment executes, for example, each step illustrated in FIG. 6 for the UE 210 connected to the own cell. Each step shown in FIG. 6 is executed when the UE 210 attaches to the source eNB 220 as an example.
  • the trigger for executing each step shown in FIG. 6 is not limited to this, and can be various triggers.
  • step S704 for example, the source eNB 220 sets the event type by transmitting the RRC reconfiguration specifying the event type determined to be set among “Event X” and “Event Y” to the UE 210, for example.
  • the source eNB 220 may set both “Event X” and “Event Y” in the UE 210.
  • the source eNB 220 sets an event type by transmitting an RRC reconfiguration specifying “Event X” and “Event Y” to the UE 210.
  • FIG. 8 is a flowchart illustrating an example of the HO process performed by the source eNB according to the embodiment.
  • the source eNB 220 executes the steps illustrated in FIG. 8 together with the steps illustrated in FIG. 7 for the UE 210 connected to the own cell.
  • the source eNB 220 determines whether or not a report signal has been received from the UE 210 (step S801), and waits until a report signal is received (step S801: No loop).
  • the report signal is, for example, the above-described measurement report.
  • step S804 when the value of the RACH less flag is not “on” (step S804: No), the source eNB 220 performs legacy HO to the target eNB 230 for the UE 210 (step S806), and ends a series of processes.
  • step S806 for example, the source eNB 220 transmits a handover request requesting legacy HO of the UE 210 to the target eNB 230, and obtains a response (Ack) from the target eNB 230.
  • source eNB220 implements legacy HO by transmitting RRC reconfiguration which instruct
  • step S802 when the event type set in the UE 210 is not “Event Y” but “Event X” (step S802: No), the source eNB 220 proceeds to step S807. That is, the source eNB 220 acquires the TA value included in the received report signal (step S807). Next, the source eNB 220 determines whether or not the deviation amount indicated by the TA value acquired in step S807 is equal to or less than a threshold value (step S808).
  • the RF processing unit 910 performs an RF reception process on the signal output from the antenna 901.
  • RF is an abbreviation for Radio Frequency.
  • the RF reception processing by the RF processing unit 910 includes, for example, amplification, frequency conversion from the RF band to the baseband, conversion from an analog signal to a digital signal, and the like.
  • the RF processing unit 910 outputs the signal subjected to the RF reception processing to the PHY / MAC processing unit 920.
  • the RF processing unit 910 performs RF transmission processing on each signal output from the PHY / MAC processing unit 920.
  • the RF transmission processing by the RF processing unit 910 includes, for example, conversion from a digital signal to an analog signal, frequency conversion from a baseband to an RF band, amplification, and the like.
  • the RF processing unit 910 outputs the signal subjected to the RF transmission process to the antenna 901.
  • the measurement control unit 931 instructs the TA measurement unit 932 to perform TA measurement, and displays the TA measurement result (TA value). Obtained from the TA measurement unit 932.
  • the event type related to the TA measurement is, for example, “Event X” or “Event Y” described above.
  • the calculation unit 111 of the terminal 110 illustrated in FIG. 1 can be realized by the TA measurement unit 932, for example.
  • the transmission unit 112 of the terminal 110 illustrated in FIG. 1 can be realized by the antenna 901, the RF processing unit 910, and the PHY / MAC processing unit 920, for example.
  • the control unit 113 illustrated in FIG. 1 can be realized by the antenna 901, the RF processing unit 910, the PHY / MAC processing unit 920, and the call processing control unit 933, for example.
  • the processor 1001 is a circuit that performs signal processing, for example, a CPU (Central Processing Unit) that controls the entire wireless communication apparatus 1000.
  • the memory 1002 includes, for example, a main memory and an auxiliary memory.
  • the main memory is, for example, a RAM (Random Access Memory).
  • the main memory is used as a work area for the processor 1001.
  • the auxiliary memory is a non-volatile memory such as a magnetic disk or a flash memory.
  • Various programs for operating the wireless communication apparatus 1000 are stored in the auxiliary memory. The program stored in the auxiliary memory is loaded into the main memory and executed by the processor 1001.
  • the antenna 1101 receives a signal wirelessly transmitted from another wireless communication device (for example, the UE 210), and outputs the received signal to the RF processing unit 1110.
  • the antenna 1101 wirelessly transmits the signal output from the RF processing unit 1110 to another wireless communication device.
  • the control information setting unit 1130 performs processing based on the control signal output from the PHY / MAC processing unit 1120 and outputs the control signal obtained by the processing based on the control signal to the wired processing unit 1150.
  • the control information setting unit 1130 performs processing based on the control signal output from the wired processing unit 1150, and outputs the control signal obtained by the processing based on the control signal to the PHY / MAC processing unit 1120.
  • the control information setting unit 1130 includes a measurement control unit 1131 and a handover control unit 1132.
  • the measurement control unit 1131 controls measurement and reporting of radio quality in the UE 210.
  • the above-described event type setting and report signal reception are performed by the measurement control unit 1131.
  • the handover control unit 1132 performs HO control in the UE 210.
  • the handover control unit 1132 controls the determination of the implementation of HO and the determination of the HO method based on the report signal from the UE 210 described above based on the reception result of the report signal by the measurement control unit 1131.
  • the receiving unit 121 of the first base station 120 shown in FIG. 1 can be realized by the antenna 1101, the RF processing unit 1110, and the PHY / MAC processing unit 1120, for example.
  • the control unit 122 of the first base station 120 illustrated in FIG. 1 can be realized by the antenna 1101, the RF processing unit 1110, the PHY / MAC processing unit 1120, and the handover control unit 1132, for example.
  • the wireless communication interface 1203 is a communication interface that communicates with the outside of the wireless communication apparatus 1200 (for example, the UE 210) wirelessly.
  • the wireless communication interface 1203 is controlled by the processor 1201.
  • the wired communication interface 1204 is a communication interface that performs communication with the outside of the wireless communication device 1200 (for example, an adjacent base station or a higher-level device of the core network) by wire.
  • the wired communication interface 1204 is controlled by the processor 1201, for example.
  • the antenna 1101 and the RF processing unit 1110 illustrated in FIG. 11 are included in the wireless communication interface 1203, for example.
  • the PHY / MAC processing unit 1120, the control information setting unit 1130, and the user signal processing unit 1140 illustrated in FIG. 11 can be realized by the processor 1201 and the memory 1202, for example.
  • the wired processing unit 1150 illustrated in FIG. 11 is included in the wired communication interface 1204, for example.
  • the item 1301 (eventX) of the information element 1300 indicates the definition of “Event X” described above.
  • Event Y can be similarly defined in the information element 1300.
  • the source eNB 220 can set “Event X” and “Event Y” in the UE 210 by, for example, the RRC reconfiguration described above.
  • UE 210 detects the reception timing of each reference signal from source eNB 220 and target eNB 230 transmitted in steps S1601 and S1602 (step S1603). For example, the UE 210 detects the timing at which a signal having a predetermined pattern corresponding to the reference signal in the radio signal from the source eNB 220 is detected as the reception timing of the reference signal from the source eNB 220. Moreover, UE210 detects the timing which detected the signal of the predetermined pattern corresponding to a reference signal in the radio signal from target eNB230 as a reception timing of the reference signal from target eNB230.
  • the UE 210 calculates the TA value of the target eNB 230 based on the difference between the reception timings detected in step S1603 (step S1604). For example, the UE 210 divides the difference between the reception timings detected in step S1603 by the time of one slot, sets the remainder as a reception time difference, and calculates the TA value of the target eNB 230 based on the calculated reception time difference.
  • the UE 210 corrects the calculated reception time difference with the shift amount indicated by the TA value of the source eNB 220, and derives the TA value corresponding to the corrected reception time difference as the TA value of the target eNB 230.
  • the first handover method and the second handover method are based on the amount of deviation between the radio signal transmission timing of the terminal and the reference timing of the handover destination cell of the terminal. Can be switched. As a result, the first handover method and the second handover method can be switched according to the possibility of the successful handover of the terminal to the second cell by the second handover method. For this reason, the time taken for the handover can be shortened.
  • the amount of deviation between the terminal radio signal transmission timing and the terminal handover destination cell reference timing is, for example, the TA value of the target eNB 230 in the UE 210 described above.
  • the first handover method is a handover method including a random access procedure, and an example is the above-described RACH-less HO.
  • the second handover method is a handover method that does not include at least a part of the random access procedure, and an example is the above-described legacy HO.
  • T304 (50 [ms] or more) is defined as a UE timer used for determining to stop HO.
  • T304 is set by eNB, for example.
  • eNB for example.
  • a process of setting a timer shorter than T304 and switching from RACH-less HO to legacy HO (HO performing RACH procedure) when the short timer expires has been proposed.
  • RACH-less HO failure is repeated until the timer expires, and the time required for HO becomes long.
  • a parameter related to RACH-less HO can be acquired from a downlink signal (for example, a reference signal) of the target eNB and can be used for selection of RACH-less HO. . That is, the HO method can be selected based on the timing information (for example, TA value) of the target eNB.

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Abstract

Selon l'invention, une première station de base (120) comprend une unité de réception (121) et d'une unité de commande (122). L'unité de réception (121) reçoit, d'un terminal (110) connecté à une première cellule de la station locale, une valeur qui indique une divergence entre l'instant de transmission d'un signal sans fil du terminal (110) et l'instant de référence d'une seconde cellule différente de la première cellule. L'unité de commande (122) sélectionne un procédé de transfert, sur la base de la valeur reçue par l'unité de réception (121), parmi un premier procédé de transfert comprenant une procédure d'accès aléatoire et un second procédé de transfert ne comprenant pas au moins une partie de la procédure d'accès aléatoire. L'unité de commande (122) exécute une instruction pour commuter une destination de connexion du terminal (110) à la seconde cellule par le procédé de transfert sélectionné.
PCT/JP2016/089115 2016-12-28 2016-12-28 Station de base, terminal, système de communication, et procédé de communication Ceased WO2018123025A1 (fr)

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JPWO2020194759A1 (fr) * 2019-03-28 2020-10-01
US20220015131A1 (en) * 2018-11-20 2022-01-13 Peng Cheng Random access channel (rach)-less procedure
CN114363801A (zh) * 2021-12-22 2022-04-15 北京红山信息科技研究院有限公司 一种基于时间序列的邻区ta回填方法及三角定位方法

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220015131A1 (en) * 2018-11-20 2022-01-13 Peng Cheng Random access channel (rach)-less procedure
US12245241B2 (en) * 2018-11-20 2025-03-04 Qualcomm Incorporated Random access channel (RACH)-less procedure
JPWO2020194759A1 (fr) * 2019-03-28 2020-10-01
WO2020194759A1 (fr) * 2019-03-28 2020-10-01 株式会社Ｎｔｔドコモ Dispositif utilisateur et procédé de communication
JP7265616B2 (ja) 2019-03-28 2023-04-26 株式会社Ｎｔｔドコモ 端末、通信方法、及びシステム
CN114363801A (zh) * 2021-12-22 2022-04-15 北京红山信息科技研究院有限公司 一种基于时间序列的邻区ta回填方法及三角定位方法
CN114363801B (zh) * 2021-12-22 2024-04-26 北京红山信息科技研究院有限公司 一种基于时间序列的邻区ta回填方法及三角定位方法

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