JP2015173392A - Base station device, control method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in utilization efficiency of a radio resource when communication quality between eNBs deteriorates.SOLUTION: A base station device in a radio communication system where one base station device and another base station device which is connected to the one base station device and transmits data transferred from the one base station device to a communication device can simultaneously transmit data to the communication device, determines when a signal relevant to one piece of transmission data addressed to the communication device is transmitted to the other base station device, whether a predetermined time period has elapsed without confirmation of transmission success of the signal, and terminates connection with the other base station device when determining that the predetermined time period has elapsed.

Description

  The present invention relates to a radio resource control technique in a radio communication system.

  In the 3rd Generation Partnership Project (3GPP), installing many small cells (small cells) that use different frequency bands (for example, higher frequency bands than those used in macro cells) within the coverage of large cells (macro cells) Has been discussed. For example, as in the example of FIG. 1, a plurality of small cells using the 3.5 GHz band frequency band are placed in the coverage area of the macro cell using the 2 GHz band frequency band.

  In LTE Release 12, discussions have begun on a technology called Dual Connectivity in which two types of base stations cooperate in a layer higher than a MAC (medium access control) layer in such an environment (Non-Patent Document 1). The two types of base stations are a master eNodeB (master eNB, eg, a macro base station) and a secondary eNodeB (secondary eNB, eg, a small cell base station). For example, the master eNB leads communication control, and the secondary eNB operates based on the communication control. In Dual Connectivity, it is assumed that two types of base stations are connected by a wired or wireless backhaul line, for example, traffic transmitted to the terminal is passed to the secondary eNB via the master eNB. . The passed signal is then transmitted as a radio signal from the secondary eNB to the terminal. Moreover, the signal transmitted from the terminal to the secondary eNB is transferred from the secondary eNB to the master eNB. That is, all or most of the traffic passes through the master eNB once.

  Here, the backhaul line is required to have a large capacity such as 1 Gbps, for example, while the request for the delay is not relatively severe such as 10 msec or more. Therefore, as shown in FIG. 2, in dual connectivity, control data (C-plane) for maintaining mobility and data with high real-time properties such as voice call traffic are transmitted from the master eNB to the terminal. On the other hand, best-effort user data (U-plane) that does not require real-time performance such as Web browsing is transmitted from the secondary eNB to the terminal. Thereby, it is possible to perform data offloading to the secondary eNB without performing a handover associated with the connection to the secondary eNB.

Samsun, R1-131830, “Discussion on dual RRC”, 3GPP TSG RAN WG2 # 82, May 2013

  In Dual Connectivity, it is assumed that the secondary eNB establishes a wireless connection with the terminal or disconnects the wireless connection and releases resources in accordance with an instruction from the master eNB. At this time, for example, when the communication quality between the master eNB and the secondary eNB is greatly deteriorated due to congestion or the like, an instruction from the master eNB may not reach the secondary eNB in some cases. In this case, in addition to not being able to transfer data from the master eNB to the secondary eNB, even if the master eNB transmits a resource release instruction to the secondary eNB, the secondary eNB may not receive it. It is done. Then, although the secondary eNB cannot receive data to be transmitted to the terminal, the radio resource cannot be released, and the use efficiency of the radio resource may be reduced.

  This invention is made | formed in view of the said subject, and it aims at preventing the utilization efficiency of a radio | wireless resource, when the communication quality between eNB deteriorates.

  In order to achieve the above object, a base station apparatus according to the present invention includes a base station apparatus and another base station apparatus that connects to the base station apparatus and transmits data transferred from the base station apparatus to a communication apparatus. In the wireless communication system capable of transmitting data to the communication device at the same time, when the base station device transmits a signal related to one transmission data addressed to the communication device to the other base station device, A determination unit that determines whether or not a predetermined time has passed without confirming the successful transmission of the signal, and a connection between the other base station device when the determination unit determines that the predetermined time has elapsed Cutting means for cutting.

  In order to achieve the above object, another base station apparatus according to the present invention is connected to the base station apparatus and the base station apparatus and transfers other data to the base station apparatus and transmits it to the communication apparatus. In the wireless communication system in which a base station apparatus can simultaneously transmit data to the communication apparatus, the base station apparatus receives a signal related to one transmission data addressed to the communication apparatus from the other base station apparatus. Determining means for determining whether a predetermined time has passed without receiving another signal, and disconnecting the communication device when the determining means determines that the predetermined time has elapsed Cutting means.

  ADVANTAGE OF THE INVENTION According to this invention, when the communication quality between eNB deteriorates, it can prevent that the utilization efficiency of a radio | wireless resource deteriorates.

The conceptual diagram which shows the example of arrangement | positioning of the macro cell and small cell which each use a different frequency band. The conceptual diagram which shows the example of communication between the terminal and multiple eNB by Dual Connectivity. The sequence diagram which shows the flow of the process which concerns on embodiment. The figure which shows the hardware structural example of the master eNB and the secondary eNB. The block diagram which shows the function structural example of the master eNB and the secondary eNB.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(System configuration)
The radio communication system according to the present embodiment includes, for example, a master eNB, a secondary eNB, and a terminal (UE) as illustrated in FIG. Here, eNB is a base station apparatus, but the corresponding wireless communication system may be other than LTE. The terminal is a mobile unit or a fixed radio communication device, and may correspond to a radio communication system other than LTE. Note that in the wireless communication system of the present embodiment, the master eNB performs communication using a first frequency band (for example, 2 GHz), and the secondary eNB performs communication using a second frequency band (3.5 GHz).

  The master eNB and the secondary eNB are connected to each other by a wired or wireless communication line (backhaul line). And a downlink signal arrives at a terminal by being transmitted to a terminal as a radio signal directly from a master eNB, or being transmitted as a radio signal from a secondary eNB to a terminal after being transferred from a master eNB to a secondary eNB . Further, the uplink signal reaches the master eNB when the terminal directly transmits to the master eNB or when the secondary eNB transfers a signal transmitted from the terminal to the secondary eNB to the master eNB. Note that communication between the terminal and another device directly connected to the secondary eNB may not pass through the master eNB.

  Note that FIG. 2 shows the case where only one secondary eNB exists, but the following discussion can be applied to any case where one or more secondary eNBs exist. Further, FIG. 2 shows a case where only one terminal exists, but the following discussion can be applied to any case where one or more terminals exist. .

  The master eNB can control not only the wireless connection between itself and the terminal but also the wireless connection between the secondary eNB and the terminal. In this case, for example, the secondary eNB waits for an instruction from the master eNB to disconnect the radio connection with the terminal, that is, to release the radio resource. However, when the communication quality of the backhaul line connecting the master eNB and the secondary eNB deteriorates, there is a case where the instruction from the master eNB to the secondary eNB does not reach. The deterioration of the communication quality of the backhaul line can occur, for example, when there is congestion or when the communication quality of the radio entrance line is significantly deteriorated when the secondary eNB is a mobile base station device. In this case, since the transmission data does not reach, the secondary eNB may not be able to release radio resources even though it does not have data to transmit to the terminal. Similarly, if it is not confirmed that the radio resource is released between the secondary eNB and the terminal, the master eNB is also transferred to the terminal with respect to the secondary eNB even if the communication quality of the backhaul line is deteriorated. It is possible to continue sending the transmission data to be transmitted.

  For this reason, in this embodiment, in such a case, the master eNB and the secondary eNB autonomously disconnect the connection in the backhaul line, and release the radio resources between the secondary eNB and the terminal. Thereby, even if there is no instruction | indication from the master eNB, the secondary eNB can release a radio | wireless resource autonomously. In addition, even if it is not confirmed that the radio resource between the secondary eNB and the terminal has been released, the master eNB assumes that the secondary eNB has released the radio resource and transfers the transmission data to the secondary eNB. Can be stopped. A specific example of the processing flow of this method will be described below with reference to FIG.

(Process flow)
In this example, both the master eNB and the secondary eNB have a timer. Then, when the master eNB transfers a signal related to one transmission data addressed to the terminal to the secondary eNB, when a predetermined time elapses without confirming the successful transmission of the signal, the master eNB connects to the secondary eNB. It is determined that the state of has deteriorated. Similarly, when the secondary eNB receives a signal related to one transmission data addressed to the terminal from the master eNB and then does not receive another signal from the master eNB, the secondary eNB connects to the master eNB. It is determined that the state of has deteriorated. If the master eNB determines that the state of connection with the secondary eNB has deteriorated, the master eNB disconnects the connection with the secondary eNB. If the secondary eNB determines that the state of the connection with the master eNB has deteriorated, the secondary eNB disconnects the connection with the terminal and releases the radio resources. Note that the master eNB can also perform at least one of transmission and reception of information related to the stop of the connection between the secondary eNB and the terminal with the terminal.

  The predetermined time used for determining whether the connection state of the master eNB has deteriorated and the predetermined time used for determining whether the connection state of the secondary eNB have deteriorated are set to the same length. Alternatively, different times may be set. That is, the reference length of time that the master eNB determines to disconnect from the secondary eNB may be the same as the reference length of time that the secondary eNB determines to disconnect from the terminal. May be different. In addition, the length of this time may be determined and set independently by the master eNB and the secondary eNB, or the master eNB determines the respective predetermined times of itself and the secondary eNB in a lump. Then, the secondary eNB may be notified. In the latter case, the master eNB can collectively manage the length of the predetermined time in each of the master eNB and the secondary eNB.

  As a result, when the master eNB cannot transmit data to the secondary eNB, the secondary eNB wirelessly secures the connection with the terminal autonomously without an instruction from the master eNB. Resources can be released. Also, the master eNB can prevent unnecessary retransmission of data to the secondary eNB. Furthermore, since the secondary eNB autonomously releases radio resources, the master eNB may expect the secondary eNB to release radio resources even when the state of connection with the secondary eNB is significantly degraded. it can. Therefore, the master eNB can predict the movement of the secondary eNB and execute control for canceling the Dual Connectivity state with the terminal.

  Here, in one example, the timer of the master eNB measures the time after transmitting a signal related to one transmission data to be transmitted to the terminal to the secondary eNB. That is, in this case, the timer of the master eNB is reset to, for example, zero at the timing when the signal related to a certain piece of transmission data is transferred to the secondary eNB, and the time during which transmission of the signal related to that one piece of transmission data is not confirmed Measure. When it is confirmed that the signal has been successfully transmitted, a signal relating to another transmission data is transmitted, so that the timer is reset at the transmission timing. By doing in this way, the master eNB can determine whether or not the signal transferred to the secondary eNB has arrived, and can grasp the state of the connection with the secondary eNB. At this time, if a signal for a certain piece of transmission data is retransmitted, the signal has not arrived, so the timer is not reset. That is, the elapsed time from the first signal transmission is measured for one piece of data by the timer. Note that “retransmission” here does not require the same signal to be retransmitted. For example, the signal transmitted after the second time may be a part of the signal transmitted for the first time, and includes redundant bits for error correction that were not transmitted with the signal transmitted for the first time. It may be a signal.

  In another example, when the timer of the master eNB transmits a signal related to one transmission data to be transmitted to the terminal to the secondary eNB, the timer of the master eNB measures the time after receiving the confirmation response to the signal from the secondary eNB. . That is, in this case, the timer of the master eNB is reset to, for example, zero at a timing when a response to a signal related to a certain piece of transmission data is received, and the time during which transmission of the signal related to that one piece of transmission data is not confirmed is confirmed. measure. Thereby, the master eNB can determine at least one of whether the signal transferred to the secondary eNB has stopped reaching or whether the response from the secondary eNB has stopped reaching, and the state of the connection with the secondary eNB Will be able to grasp. If a response from the secondary eNB is received, the master eNB timer may be reset even if it is a negative response (NACK) rather than an acknowledgment (ACK). The negative response indicates that the signal transmitted from the master eNB to the secondary eNB has arrived but contains an error, and thus indicates that communication between the master eNB and the secondary eNB cannot be performed. It is not a thing. The timer may be reset when the response reaches the medium access control (MAC) layer. In addition, the timer may be reset at another timing at which it can be determined that a response has been received.

  On the other hand, in one example, the timer of the secondary eNB measures the time after receiving a signal related to one transmission data to be transmitted from the master eNB to the terminal. That is, in this case, the timer of the secondary eNB is reset to, for example, zero at a timing when a signal related to a certain piece of transmission data is received, and then measures the time when the signal is not sent. Here, the state in which no signal is received despite not receiving an instruction for disconnection (release of radio resources) from the master eNB to the terminal, although the signal is transmitted from the master eNB, It is considered that the signal does not reach the secondary eNB. Therefore, the secondary eNB grasps the state of the connection between the master eNB and the secondary eNB by measuring the length of the period in which the signal is not received after the signal related to a certain transmission data is received. Can do. The timer may be reset when the signal from the master eNB reaches the medium access control (MAC) layer. By making such a determination not in the upper layer but in a lower layer such as the MAC layer, the communication status can be quickly confirmed. In addition, the timer may be reset at another timing at which it can be determined that a signal from the master eNB has been received.

  Further, in another example, when the timer of the secondary eNB receives a signal related to one piece of transmission data to be transmitted from the master eNB to the terminal, the timer of the secondary eNB measures the time after transmitting a response to the signal. The response may be either an acknowledgment (ACK) or a negative response (NACK).

  FIG. 3 is a sequence diagram showing a flow of processing according to the present embodiment. As an initial state, it is assumed that the terminal establishes a connection between the master eNB and the secondary eNB by dual connectivity and can receive signals from these eNBs simultaneously. FIG. 3 shows an example in which the timer of the master eNB is reset when a response from the secondary eNB is received, and the timer of the secondary eNB is reset when a response is transmitted to the master eNB.

  In FIG. 3, the master eNB transmits data addressed to the terminal to the secondary eNB in addition to transmitting data to the terminal (S301) by dual connectivity (S302). Upon receiving this, the secondary eNB transmits, for example, an acknowledgment (ACK) to the master eNB (S303), while transmitting data received from the master eNB to the terminal (S304). In addition, although the data which the secondary eNB receives from the master eNB and the signal which the secondary eNB transmits to a terminal share data, they may have different formats. For example, different control information can be added to each signal.

  When receiving the response from the secondary eNB, the master eNB resets the timer (S305). Similarly, when the secondary eNB transmits a response to the master eNB, the timer is reset (S306). In addition, the timing which resets a timer may be the timing when the response arrived at the MAC layer for the master eNB, for example, and may be the timing when the response is output from the MAC layer for the secondary eNB, for example. Note that here, this timing may not be strictly the timing at which the response is transmitted or received, and the response including the period included in the predetermined time range from the timing of transmission or reception of these responses. Is referred to as the timing of transmission or reception.

  Thereafter, the master eNB repeats data transmission to the terminal (S307) and data transfer to the secondary eNB (S308), and resets the timer when receiving a response from the secondary eNB (S309) (S311). ). Similarly, the secondary eNB transmits a response (acknowledgment or negative response) when receiving a signal from the master eNB to the master eNB (S309) and transmits data received from the master eNB to the terminal (S310). And repeat. And secondary eNB resets a timer, when a response is transmitted to master eNB (S312).

  Here, it is assumed that the communication quality in the connection between the master eNB and the secondary eNB is deteriorated due to, for example, congestion after the timers of S311 and S312 are reset, and communication becomes impossible. In this case, the signal transmitted directly from the master eNB to the terminal is received at the terminal (S314, S316), but the signal transmitted from the master eNB to the secondary eNB cannot be received at the secondary eNB (S315, S317).

  Then, since the master eNB does not receive a response from the secondary eNB, the timer is not reset. Similarly, since the secondary eNB does not receive a signal from the master eNB and does not transmit a response, the timer is not reset. For this reason, when the state of the connection between the master eNB and the secondary eNB does not recover, these timers reach a predetermined time (S318, S319). When the time measured by the timer reaches a predetermined time, both the master eNB and the secondary eNB determine that the state of the connection with the partner eNB is in a state where communication is not possible, and disconnect the connection between the eNBs. To do. Then, the secondary eNB transmits a signal for releasing radio resources to the terminal (S322). At this time, the master eNB may perform at least one of transmission and reception of control information with respect to termination of Dual Connectivity, that is, with respect to termination of connection between the secondary eNB and the terminal. Yes (not shown).

  In the above description, the master eNB and the secondary eNB have been described using the timer to specify the connection state between the eNBs, but the master eNB uses, for example, a counter that counts the number of signal retransmissions. The state of connection between eNBs may be determined. That is, it is conceivable that the master eNB retransmits data when there is no response even when a negative response does not arrive. In such a case, the master eNB counter counts the number of times a signal related to one data is transmitted. That is, the master eNB counter is reset to zero when a successful transmission of data for one data is confirmed (eg, by receiving an ACK) and a signal for another data is transmitted. The master eNB determines whether or not the number of times that the signal related to one piece of data has been retransmitted has reached a predetermined number of times, without confirming the successful transmission of the signal related to that one piece of data. It can be determined whether the time has elapsed. In this case, it should be noted that the “predetermined time” may vary from signal to signal due to, for example, fluctuation in timing at which retransmission is performed. In this way, the master eNB can determine that communication is not possible in the connection with the secondary eNB using a counter that measures the number of retransmissions instead of the above-described timer.

  Note that this counter may be reset when a negative response is received from the secondary eNB. Further, this counter may be configured not to count the number of times when a signal is retransmitted in response to a negative response from the secondary eNB. If a negative response is received, the signal is retransmitted. However, as long as the signal transmitted by the master eNB is received in some form by the secondary eNB and a response to it is received, no communication is made in the connection between the eNBs. This is because it is not impossible. Further, here, as in the case described above, not only the completely identical signal is retransmitted, but also when the signal transmitted for the first time and the signal transmitted for the second time are different, If it is based on one piece of transmission data, it is considered that the signal has been “retransmitted”.

(Configuration of master eNB and secondary eNB)
Then, the structure of the master eNB and secondary eNB which perform the above processes is demonstrated. FIG. 4 illustrates a hardware configuration example of the master eNB and the secondary eNB (base station apparatus).

  For example, the master eNB and the secondary eNB have the same hardware configuration as illustrated in FIG. 4, and include, for example, a CPU 401, a ROM 402, a RAM 403, an external storage device 404, and a communication device 405. In the master eNB and the secondary eNB, for example, the CPU 401 executes a program that realizes each function of the master eNB and the secondary eNB as described above, which is recorded in any of the ROM 402, the RAM 403, and the external storage device 404.

  Then, the master eNB and the secondary eNB, for example, control the communication device 405 by the CPU 401, and perform communication between the master eNB or secondary eNB and the terminal, or inter-eNB communication between the master eNB and the secondary eNB. In FIG. 4, the master eNB and the secondary eNB have one communication device 405. For example, the eNB may have a communication device for communication between eNBs and a communication device with a terminal. Good.

  Note that the master eNB and the secondary eNB may be provided with dedicated hardware for executing each function, or may be executed by a computer that executes a part of the hardware and executes the program. Further, all functions may be executed by a computer and a program.

  FIG. 5 shows a functional configuration example of the master eNB and the secondary eNB. The master eNB and the secondary eNB include, for example, a wireless communication unit 501, a wireless communication control unit 502, a wired communication unit 503, a wired communication control unit 504, and a timer 505.

  The wireless communication unit 501 is a functional unit for performing wireless communication, and performs wireless communication by establishing a wireless connection with a terminal, for example. The wireless communication control unit 502 is a functional unit that controls the wireless communication unit 501. The wired communication unit 503 is a functional unit for performing wired communication. For example, the wired communication unit 503 establishes a connection with another eNB and performs wired communication. The wired communication control unit 504 is a functional unit that controls the wired communication unit 503. As described above, the timer 505 is a functional unit for determining whether communication in a connection between eNBs is possible. Note that the timer 505 may be a counter that measures the number of retransmissions of a signal related to one piece of transmission data in the master eNB, as described above.

  In the master eNB, the timer 505 is reset, for example, when the wired communication unit 503 receives a response from the secondary eNB, or when a signal about one transmission data is first transmitted (first time), The elapsed time after that is measured. Then, the timer 505 is reset again when the next response is received or when transmission of another transmission data is to be transmitted. When the time measured by the timer 505 reaches a predetermined time, the wired communication control unit 504 controls the wired communication unit 503 so as to disconnect the connection with the secondary eNB. In addition, the wireless communication control unit 502 controls the wireless communication unit 501 so as to transmit / receive information related to the stop of the connection between the secondary eNB and the terminal. Thereby, based on the timer 505, the state of Dual Connectivity is canceled. Even if a counter is used instead of the timer 505, other functional units function in the same manner except that it is determined whether the number of retransmissions has reached a predetermined number.

  In the secondary eNB, the timer 505 is reset when, for example, the wired communication unit 503 receives a signal related to transmission data addressed to the terminal from the master eNB, or when a response to the signal is transmitted. Measure elapsed time. Then, the timer 505 is reset again when the next signal is received from the master eNB or when a response to the signal is transmitted. When the time measured by the timer 505 reaches a predetermined time, the wireless communication control unit 502 controls the wireless communication unit 501 to disconnect the connection with the terminal and release the wireless resources for the connection. To do. Moreover, the wire communication part 503 and the wire communication control part 504 perform the process, when the process for cut | disconnecting the connection between master eNBs is required.

  Thus, both the master eNB and the secondary eNB can autonomously determine that communication is no longer possible in connection with the counterpart eNB using the timer. For this reason, the secondary eNB releases radio resources reserved for connection with the terminal without waiting for a disconnection instruction (radio resource release instruction) from the master eNB to the terminal. can do. Furthermore, even if the master eNB is in a state where communication with the secondary eNB cannot be established, the secondary eNB knows that this connection will be disconnected, and thus disconnects this connection independently. be able to. Also, for example, by making the timer reset based on signal transmission and reception at the MAC layer, the above-mentioned determination can be performed at high speed, and the time during which radio resources are unnecessarily reserved is reduced. It becomes possible to do.

Claims (22)

In a wireless communication system in which another base station device that connects to the base station device and the base station device and transmits data transferred from the base station device to the communication device can simultaneously transmit data to the communication device, The base station device,
A determination means for determining whether a predetermined time has passed without confirming a successful transmission of the signal when transmitting a signal related to one transmission data addressed to the communication device to the other base station device;
When the determination unit determines that the predetermined time has elapsed, a disconnection unit that disconnects the connection with the other base station device;
A base station apparatus comprising: The determination means includes a timer that is reset when a signal related to one piece of transmission data addressed to the communication device is transmitted and that measures the time that has elapsed since the signal was transmitted, and the time measured by the timer Determining whether or not the predetermined time has elapsed without determining whether the signal has been successfully transmitted.
The base station apparatus according to claim 1. The timer is not reset when retransmitting a signal related to one piece of transmission data addressed to the communication device,
The base station apparatus according to claim 2. The determination means is reset when a response from the other base station apparatus is received after a signal related to one transmission data addressed to the communication apparatus is transmitted, and a time elapsed since the response was received Determining whether the time measured in the timer has reached the predetermined time, thereby determining whether the predetermined time has passed without confirming the successful transmission of the signal,
The base station apparatus according to claim 1. The timer is reset when a response from the other base station apparatus reaches a medium access control (MAC) layer.
The base station apparatus according to claim 4. The determination means is reset when there is a response from the other base station apparatus in response to transmitting a signal related to one transmission data addressed to the communication apparatus to the other base station apparatus. It includes a counter that counts the number of retransmissions when there is no response, and determines whether the predetermined time has passed without confirming the successful transmission of the signal by determining whether the number has reached the predetermined number. judge,
The base station apparatus according to claim 1. The counter does not count the retransmission when the signal is retransmitted in response to the negative response from the other base station device,
The base station apparatus according to claim 6. When the disconnection unit disconnects the connection with the other base station device, transmission and reception of information regarding the suspension of the connection between the other base station device and the communication device is performed with the communication device. A communication means for performing at least one of
The base station apparatus according to claim 1, wherein: When the other base station apparatus receives a signal related to one transmission data addressed to the communication apparatus from the base station apparatus and the other base station apparatus has not received another signal, the predetermined length of time elapses. Determining that the connection with the device is to be disconnected, different from the standard length of time,
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. When the predetermined length of time and the other base station apparatus receives a signal related to one transmission data addressed to the communication apparatus from the base station apparatus, and the other signal has not been received, the communication apparatus A determination means for determining a reference length of time for determining that the connection with the device is to be disconnected;
Notification means for notifying the other base station apparatus of the reference time length;
The base station apparatus according to claim 1, further comprising: In a wireless communication system capable of simultaneously transmitting data to the communication device, the base station device and another base station device connected to the base station device and transferring data to the base station device and transmitting the data to the communication device. The base station device,
Determining means for determining whether a predetermined time has passed without receiving another signal after receiving a signal related to one transmission data addressed to the communication device from the other base station device;
When the determination unit determines that the predetermined time has elapsed, a disconnection unit that disconnects the connection with the communication device;
A base station apparatus comprising: The determination means includes a timer that is reset when a response to the reception of the signal from the other base station apparatus is transmitted and measures a time after the response is transmitted, and is measured in the timer Determining whether the predetermined time has elapsed without receiving the other signal by determining whether time has reached the predetermined time;
The base station apparatus according to claim 11. The determination means includes a timer that is reset when a signal is received from the other base station apparatus and measures a time after receiving the signal, and a time measured by the timer is set to the predetermined time. Determining whether the predetermined time has elapsed without receiving the other signal by determining whether the other signal has been reached;
The base station apparatus according to claim 11. The timer is reset when a signal from the other base station apparatus reaches a medium access control (MAC) layer.
The base station apparatus according to claim 13. The disconnecting unit disconnects the connection with the communication device by transmitting information for disconnecting the connection between the base station device and the communication device with the communication device.
The base station apparatus according to any one of claims 11 to 14, wherein the base station apparatus is characterized in that The disconnection unit further disconnects the connection with the other base station device.
The base station apparatus according to claim 11, wherein the base station apparatus is a base station apparatus. The predetermined length of time elapses after the other base station apparatus transmits a signal related to one transmission data addressed to the communication apparatus to the base station apparatus without confirming the successful transmission of the signal. Then, it is determined that the disconnection with the base station device is disconnected, which is different from the reference time length,
The base station apparatus according to any one of claims 11 to 16, wherein the base station apparatus is characterized in that Further comprising setting means for setting the length of the predetermined time in response to a notification from the other base station device;
The base station apparatus according to claim 11, wherein: In a wireless communication system in which another base station device that connects to the base station device and the base station device and transmits data transferred from the base station device to the communication device can simultaneously transmit data to the communication device, A control method of the base station apparatus,
When the determination unit transmits a signal related to one transmission data addressed to the communication device to the other base station device, it determines whether a predetermined time has passed without confirming the successful transmission of the signal. A determination process;
When it is determined that the predetermined time has elapsed in the determination step, the disconnecting unit disconnects the connection with the other base station device, and
A control method characterized by comprising: In a wireless communication system capable of simultaneously transmitting data to the communication device, the base station device and another base station device connected to the base station device and transferring data to the base station device and transmitting the data to the communication device. A control method of the base station apparatus,
A determination step of determining whether a predetermined time has passed without receiving another signal after receiving a signal related to one transmission data addressed to the communication device from the other base station device; and
When it is determined that the predetermined time has elapsed in the determination step, the disconnecting unit disconnects the connection with the communication device,
A control method characterized by comprising: In a wireless communication system in which another base station device that connects to the base station device and the base station device and transmits data transferred from the base station device to the communication device can simultaneously transmit data to the communication device, In the computer provided in the base station apparatus,
A determination step of determining whether a predetermined time has passed without confirming the successful transmission of the signal when transmitting a signal related to one transmission data addressed to the communication device to the other base station device;
If it is determined in the determination step that the predetermined time has elapsed, a disconnection step of disconnecting the connection with the other base station device;
A program for running In a wireless communication system capable of simultaneously transmitting data to the communication device, the base station device and another base station device connected to the base station device and transferring data to the base station device and transmitting the data to the communication device. In the computer provided in the base station apparatus,
A determination step of determining whether a predetermined time has passed without receiving another signal after receiving a signal related to one transmission data addressed to the communication device from the other base station device;
If it is determined that the predetermined time has elapsed in the determination step, a disconnection step of disconnecting the connection with the communication device;
A program for running

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