JP6303333B2 - Wireless communication apparatus and control method - Google Patents

Description

  The present invention relates to a wireless communication apparatus and a control method.

  2. Description of the Related Art Conventionally, a technique for managing a buffer of data to be transmitted to a wireless terminal in a base station of a wireless communication system such as LTE (Long Term Evolution) is known (for example, see Patent Documents 1 to 4 below).

JP 2004-072379 A JP 2010-273050 A JP 2006-515551 A JP 2008-211759 A

  However, in the above-described conventional technology, it is difficult to efficiently use a buffer when congestion occurs, and it is difficult to improve throughput.

  In one aspect, an object of the present invention is to provide a wireless communication apparatus and a control method that can improve throughput.

  In order to solve the above-described problems and achieve the object, according to one aspect of the present invention, a buffer for storing each transmission data to a plurality of communication destinations is provided, and the transmission data stored in the buffer is read out. In a wireless communication apparatus that performs wireless transmission, information indicating the wireless quality of each of the plurality of communication destinations is acquired, and the buffer usage amount for each of the plurality of communication destinations is limited based on the acquired information. A wireless communication device and a control method are proposed.

  According to one aspect of the present invention, it is possible to improve the throughput.

FIG. 1A is a diagram illustrating an example of the wireless communication apparatus according to the first embodiment. 1B is a diagram illustrating an example of a signal flow in the wireless communication apparatus illustrated in FIG. 1A. FIG. 1C is a diagram illustrating an example of a hardware configuration of the wireless communication device. FIG. 2 is a diagram of an example of the communication system according to the second embodiment. FIG. 3 is a diagram illustrating an example of discarding processing of the transmission buffer. FIG. 4 is a diagram illustrating an example of a terminal management table. FIG. 5 is a diagram illustrating an example of state transition of the mobile terminal. FIG. 6 is a diagram illustrating an example of calculation of the transmission buffer usage. FIG. 7 is a flowchart illustrating an example of processing performed by the transmission buffer management unit. FIG. 8 is a flowchart illustrating an example of the first discarding process performed by the transmission buffer management unit. FIG. 9 is a flowchart illustrating an example of the second discarding process performed by the transmission buffer management unit.

  Embodiments of a wireless communication apparatus and a control method according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
(Radio communication apparatus according to the first embodiment)
FIG. 1A is a diagram illustrating an example of the wireless communication apparatus according to the first embodiment. 1B is a diagram illustrating an example of a signal flow in the wireless communication apparatus illustrated in FIG. 1A. As illustrated in FIGS. 1A and 1B, the communication system 100 according to the first embodiment includes a wireless communication device 110 and communication destinations 121 and 122 of the wireless communication device 110.

  The wireless communication device 110 is a wireless communication device capable of wireless communication with a plurality of communication destinations (communication destinations 121 and 122). For example, the wireless communication device 110 can be a wireless base station device that is connected to a network and relays communication between the communication destinations 121 and 122 and the network. In this case, the communication destinations 121 and 122 can be mobile terminals that communicate with the network via the wireless communication device 110, for example.

  The wireless communication device 110 includes a buffer 111, a transmission unit 112, an acquisition unit 113, and a control unit 114. The buffer 111 is a transmission buffer in which transmission data from the wireless communication apparatus 110 to the communication destinations 121 and 122 is stored. The transmission unit 112 reads the transmission data stored in the buffer 111 and wirelessly transmits it.

  The acquisition unit 113 acquires information indicating the wireless quality of each of the communication destinations 121 and 122. The radio quality is, for example, the reception quality at the communication destinations 121 and 122 of the radio signal transmitted from the radio communication device 110. The reception quality is, for example, reception intensity. The information indicating the radio quality can be acquired by receiving from the communication destinations 121 and 122, for example. The acquisition unit 113 outputs the acquired information to the control unit 114.

  The control unit 114 limits the amount of use of the buffer 111 for each of the communication destinations 121 and 122 based on the information output from the acquisition unit 113. For example, the control unit 114 sets the upper limit of the usage amount for each of the communication destinations 121 and 122 based on the wireless quality indicated by the information output from the acquisition unit 113. The setting of the upper limit of the usage amount may include a setting of no upper limit (upper limit = ∞). For example, when the wireless quality of the communication destination 121 is lower than that of the communication destination 122, the upper limit of the usage amount of the buffer 111 for the communication destination 121 is set lower than the upper limit of the usage amount of the buffer 111 for the communication destination 122.

  Then, the control unit 114 discards the transmission data so that the usage amount of the buffer 111 does not exceed the upper limit for each of the communication destinations 121 and 122. The discarding of the transmission data may be the discarding of the transmission data stored in the buffer 111 or the discarding of the transmission data before being stored in the buffer 111.

  As described above, the wireless communication device 110 limits the usage amount of each transmission destination of the buffer 111 according to the wireless quality of each transmission destination. As a result, transmission data to a low-quality transmission destination can be preferentially discarded, the influence on other transmission destinations can be suppressed, and throughput can be improved.

<Limit of buffer usage according to congestion state>
Further, the control unit 114 may set an upper limit of the usage amount of the buffer 111 according to the total amount of each transmission data stored in the buffer 111. For example, the control unit 114 sets the upper limit of the usage amount of the buffer 111 as the total amount of each transmission data stored in the buffer 111 is larger. As a result, it is possible to flexibly limit the use of the buffer 111 in accordance with the occurrence state of congestion, so that the throughput can be improved.

<Average communication quality>
Further, the acquisition unit 113 may acquire information obtained by averaging the wireless quality in a predetermined period. For example, the acquisition unit 113 receives information indicating the communication quality from the communication destination 121 a plurality of times, and outputs information obtained by averaging the received information to the control unit 114. Similarly, for the communication destination 122, the acquisition unit 113 receives information indicating the communication quality from the communication destination 122 a plurality of times, and outputs information obtained by averaging the received information to the control unit 114.

  Thereby, even if there is a temporary change in the radio quality, the use restriction of the buffer 111 can be stably performed. As an example, a communication destination whose wireless quality has temporarily deteriorated can be excluded from restriction. For this reason, communication can be stabilized and throughput can be improved.

(Hardware configuration of wireless communication device)
FIG. 1C is a diagram illustrating an example of a hardware configuration of the wireless communication device. The wireless communication device 110 illustrated in FIGS. 1A and 1B can be realized by the communication device 130 illustrated in FIG. 1C, for example. The communication device 130 includes a CPU 131 (Central Processing Unit), a RAM 132 (Random Access Memory), a nonvolatile memory 133, and a wireless communication interface 134. Further, when the wireless communication device 110 is a wireless base station device, the communication device 130 may include a wired communication interface 135. The CPU 131, RAM 132, nonvolatile memory 133, wireless communication interface 134 and wired communication interface 135 are connected by a bus 139.

  The CPU 131 governs overall control of the communication device 130. The RAM 132 is used as a work area for the CPU 131. The nonvolatile memory 133 is a nonvolatile memory such as a magnetic disk or a flash memory. Various programs for operating the communication device 130 are stored in the nonvolatile memory 133. The program stored in the nonvolatile memory 133 is loaded into the RAM 132 and executed by the CPU 131.

  The wireless communication interface 134 is a communication interface that performs communication with the outside of the communication device 130 (for example, communication destinations 121 and 122) wirelessly. The wireless communication interface 134 is controlled by the CPU 131. The wired communication interface 135 is a communication interface that performs communication with the outside (for example, a network) of the communication device 130 by wire. The wired communication interface 135 is controlled by the CPU 131.

  The buffer 111 shown in FIGS. 1A and 1B can be realized by the RAM 132, for example. The transmission unit 112 illustrated in FIGS. 1A and 1B can be realized by the wireless communication interface 134, for example. The acquisition unit 113 illustrated in FIGS. 1A and 1B can be realized by the wireless communication interface 134 or the wired communication interface 135, for example. The control unit 114 shown in FIGS. 1A and 1B can be realized by the CPU 131 and the RAM 132, for example.

(Embodiment 2)
(Communication system according to Embodiment 2)
FIG. 2 is a diagram of an example of the communication system according to the second embodiment. As shown in FIG. 2, the communication system 200 according to the second embodiment includes mobile terminals 211, 212,..., A radio base station apparatus 220, an access network 240, and an MME / SGW 250 (Mobility Management Entity / Serving Gateway). And the upper IP network 260. The communication system 200 is an LTE mobile phone system.

  In the communication system 200, service areas are provided to the mobile terminals 211, 212,... Using the radio base station apparatus 220 and the MME / SGW 250. The radio base station device 220 includes, for example, a base station control unit 221, a transmission path interface unit 222, a baseband processing unit 223, and a radio unit 224.

  The base station control unit 221 performs call control and maintenance control with the mobile terminals 211, 212,... And the MME / SGW 250. The transmission path interface unit 222 performs interface processing with the MME / SGW 250 and other radio base station apparatuses.

  The baseband processing unit 223 performs baseband processing in a radio interface with the mobile terminals 211, 212,. The baseband processing unit 223 includes a PDCP layer processing unit 225, a transmission buffer management unit 226, an RLC layer processing unit 227, a MAC layer processing unit 228, and a PHY layer processing unit 229.

  The PDCP layer processing unit 225 performs PDCP (Packet Data Convergence Protocol) processing. The RLC layer processing unit 227 performs RLC (Radio Link Control) layer processing. The MAC layer processing unit 228 performs MAC (Media Access Control) layer processing. The PHY layer processing unit 229 performs PHY (physical) layer processing.

  The wireless unit 224 performs conversion between the input / output baseband signal of the baseband processing unit 223 and the input / output RF signal in the wireless interface.

  The mobile terminals 211, 212,... Start data communication with the upper IP network 260 after executing call control processing with the radio base station apparatus 220 and the MME / SGW 250, respectively. Downlink data transmitted from the upper IP network 260 toward the mobile terminals 211, 212,... Is input to the radio base station apparatus 220 via the MME / SGW 250 and the access network 240.

  In the radio base station apparatus 220, the downlink data to the mobile terminals 211, 212,... Is transferred from the transmission path interface unit 222 to the PDCP layer processing unit 225 of the baseband processing unit 223. The downlink data is processed by the PDCP layer processing unit 225 and then transferred to the transmission buffer management unit 226. In parallel with this, the MAC layer processing unit 228 starts radio scheduling for the mobile terminals 211, 212,.

  The transmission buffer management unit 226 stores the downlink data of the mobile terminals 211, 212,... Output from the PDCP layer processing unit 225 in the transmission buffer. The transmission buffer is realized by, for example, a RAM provided in radio base station apparatus 220.

  In addition, the transmission buffer management unit 226 includes a wireless quality monitoring unit 230. The radio quality monitoring unit 230 monitors downlink radio quality in the mobile terminals 211, 212,. For example, the radio quality monitoring unit 230 monitors the radio quality by acquiring CQI (Channel Quality Indicator) transmitted by the mobile terminals 211, 212,... From the MAC layer processing unit 228 (reference numeral 231). CQI is identifier information indicating the radio quality in the downlink direction.

  When the wireless scheduling of the mobile terminals 211, 212,... Is performed, the MAC layer processing unit 228 reads the downlink data to the mobile terminals 211, 212,... Via the RLC layer processing unit 227. Request to H.226. The downlink data read as a response from the transmission buffer management unit 226 is subjected to baseband signal processing by the RLC layer processing unit 227, the MAC layer processing unit 228, and the PHY layer processing unit 229, and is input to the radio unit 224. The The radio unit 224 converts the input downlink data into an RF signal, and transmits the converted RF signal to the mobile terminals 211, 212,.

  The radio unit 224 is included in the radio base station device 220, but the radio unit 224 may be provided outside the radio base station device 220.

  Radio communication apparatus 110 shown in FIGS. 1A and 1B can be realized by radio base station apparatus 220, for example. Further, the communication destinations 121 and 122 shown in FIGS. 1A and 1B can be realized by the mobile terminals 211, 212,.

  The base station control unit 221 and the baseband processing unit 223 illustrated in FIG. 2 can be realized by the CPU 131 and the RAM 132 illustrated in FIG. 1C, for example. 2 can be realized by the wireless communication interface 134 shown in FIG. 1C, for example. 2 can be realized by the wired communication interface 135 shown in FIG. 1C, for example.

(Transmission buffer discard processing)
FIG. 3 is a diagram illustrating an example of discarding processing of the transmission buffer. The transmission buffer 300 illustrated in FIG. 3 is a transmission buffer of the communication system 200 managed by the transmission buffer management unit 226 illustrated in FIG. The vertical axis in FIG. 3 indicates the usage amount of the transmission buffer 300. The transmission buffer management unit 226 shares a transmission buffer for the mobile terminals 211, 212,.

  Then, the transmission buffer management unit 226 uses the transmission buffer 300 based on the overall usage state of the transmission buffer 300 and the radio quality of the mobile terminals 211, 212,... Monitored by the radio quality monitoring unit 230. Implement the restrictions in stages.

  For example, the transmission buffer management unit 226 reduces the usage limit for each mobile terminal of the transmission buffer 300 in a state where the total usage amount of the transmission buffer 300 is small and does not exceed the threshold value TH1 (low limit). The control for reducing the limit may include, for example, a case where the usage amount of the transmission buffer 300 for each mobile terminal is not limited.

  In addition, when the total usage amount of the transmission buffer 300 increases and exceeds the threshold value TH1, the transmission buffer management unit 226 performs a moderate restriction on the usage amount of the transmission buffer 300 for each mobile terminal (being restricted). . In addition, when the total usage amount of the transmission buffer 300 further increases and exceeds the threshold value TH2 (> TH1), the transmission buffer management unit 226 performs a great restriction on the usage amount of each mobile terminal of the transmission buffer 300 ( Large limit). In the example illustrated in FIG. 3, a case where the restriction of three stages is performed according to the usage amount of the transmission buffer 300 is described, but the number of restriction stages may be two stages or four or more stages.

(Terminal management table)
FIG. 4 is a diagram illustrating an example of a terminal management table. The transmission buffer management unit 226 manages, for example, the terminal management table 400 shown in FIG. The terminal management table 400 is stored in the RAM 132 provided in the radio base station device 220, for example.

  In the terminal management table 400, “terminal ID”, “wireless quality state”, “average wireless quality information”, “first transmission buffer usage”, and “second transmission buffer usage” correspond to each other. It is attached. The “terminal ID” is identification information of the mobile terminals 211, 212,... That are performing wireless communication with the wireless base station device 220. The trigger for registering or deleting the “terminal ID” in the terminal management table 400 is given from the PDCP layer processing unit 225 in accordance with the call control process with the mobile terminal, for example.

  The “radio quality state” indicates the radio quality state of the corresponding mobile terminal, and is set based on the “radio quality information average”. For example, “normal state” of “wireless quality state” indicates that the “radio quality information average” of the corresponding mobile terminal exceeds a threshold value (for example, 3). Further, the “radio quality degradation state” of the “radio quality state” indicates that the “radio quality information average” of the corresponding mobile terminal is equal to or less than a threshold value. The initial value of the “wireless quality state” can be set to “normal state”, for example.

  The “radio quality information average” is an average value (for example, moving average) of downlink radio quality (for example, CQI) received by the radio base station apparatus 220 from the corresponding mobile terminal. “Radio quality information average” is set based on a notification from the MAC layer processing unit 228, for example.

  The “first transmission buffer usage amount” and the “second transmission buffer usage amount” are upper limits of the usage amount [Byte] of the transmission buffer 300 for the corresponding mobile terminal. The “first transmission buffer usage amount” is an upper limit higher than the “second transmission buffer usage amount”. The “first transmission buffer usage amount” and the “second transmission buffer usage amount” are set based on, for example, “radio quality information average”. The setting of “first transmission buffer usage” and “second transmission buffer usage” will be described later (see, for example, FIG. 6).

(Mobile terminal state transition)
FIG. 5 is a diagram illustrating an example of state transition of the mobile terminal. In the transmission buffer management unit 226, each of the mobile terminals 211, 212,... That is performing radio communication with the radio base station apparatus 220 is in a normal state 501 or a radio quality degradation state 502, as shown in FIG. Become.

  For example, when the mobile terminals 211, 212,... Are in the normal state 501, if the wireless quality is lowered, the mobile terminal 211, 212,. As an example, when the average value of the radio quality information within a unit time (for example, 5 seconds) becomes a threshold value (for example, 3) or less, a transition from the normal state 501 to the radio quality degradation state 502 occurs.

  Further, each of the mobile terminals 211, 212,... Returns to the normal state 501 when the radio quality is restored after the radio quality deteriorated state 502 is reached. As an example, when the average value of the radio quality information within a unit time (for example, 5 seconds) exceeds a threshold value (for example, 3), a transition from the radio quality degradation state 502 to the normal state 501 occurs.

  Since each mobile terminal temporarily deteriorates or recovers wireless quality due to movement or the like, if the transmission buffer usage is limited in such a transient state, unnecessary data loss may occur. For this reason, as described above, it is possible to stabilize the communication by determining the radio quality degradation and the continuity of recovery and generating a transition event. The unit time and the threshold value may be statically set by the network designer.

(Calculation of send buffer usage)
FIG. 6 is a diagram illustrating an example of calculation of the transmission buffer usage. The transmission buffer management unit 226 can acquire the table 600 shown in FIG. 6, for example. The table 600 is stored in the RAM 132 or the nonvolatile memory 133 provided in the radio base station apparatus 220, for example. In the table 600, “average radio quality information” and “buffer usage” are associated with each other.

  “Average radio quality information” in the table 600 is an average value of radio quality information corresponding to “average radio quality information” in the terminal management table 400 shown in FIG. “Buffer usage” is the upper limit of the transmission buffer usage [Byte] of the radio base station apparatus 220. In the terminal management table 400, the higher the “radio quality information average” is, the larger the “buffer usage” is associated with.

  The transmission buffer management unit 226 acquires, from the table 600, “buffer usage” corresponding to “average radio quality information” for mobile terminals whose “radio quality state” is “radio quality degraded state” in the terminal management table 400. . Then, the transmission buffer management unit 226 sets the acquired “buffer usage” as the “second transmission buffer usage” of the corresponding mobile terminal in the terminal management table 400.

  For example, in the terminal management table 400 shown in FIG. 4, the “radio quality information average” of the mobile terminal whose “terminal ID” is “2” is “0”. Therefore, the transmission buffer management unit 226 sets “4,000” of “buffer usage” corresponding to “0” of “average radio quality information” in the table 600 to ““ of the terminal ID ”of the terminal management table 400. Set to “second transmission buffer usage” corresponding to 2 ″.

  In addition, the transmission buffer management unit 226 sets “buffer quality” corresponding to a value obtained by adding, for example, 3 to “average radio quality information” for a mobile terminal whose “radio quality status” is “radio quality degraded” in the terminal management table 400. “Usage amount” is acquired from the table 600. Then, the transmission buffer management unit 226 sets the acquired “buffer usage” as the “first transmission buffer usage” of the corresponding mobile terminal in the terminal management table 400.

  For example, in the terminal management table 400 shown in FIG. 4, the value obtained by adding 3 to “average radio quality information” of the mobile terminal whose “terminal ID” is “2” is “3”. Therefore, the transmission buffer management unit 226 sets “16,000” of “buffer usage” corresponding to “3” of “radio quality information average” in the table 600 as “terminal ID” of the terminal management table 400. Set to “first transmission buffer usage” corresponding to 2 ″.

(Processing by the transmission buffer manager)
FIG. 7 is a flowchart illustrating an example of processing performed by the transmission buffer management unit. The transmission buffer management unit 226 executes, for example, each step shown in FIG. First, the transmission buffer management unit 226 determines whether or not the total usage amount of the transmission buffer exceeds the threshold value TH1 (step S701), and waits until the total usage amount exceeds the threshold value TH1 (step S701). Step S701: No loop). When the total usage amount of the transmission buffer exceeds the threshold value TH1 (step S701: Yes), the transmission buffer management unit 226 determines whether or not the total usage amount of the transmission buffer is equal to or less than the threshold value TH2. (Step S702).

  In step S702, when the total use amount is equal to or less than the threshold value TH2 (step S702: Yes), the transmission buffer management unit 226 executes the first discarding process (step S703), and the process returns to step S701. The first discard process will be described later (see, for example, FIG. 8). If the total usage exceeds the threshold value TH2 (step S702: No), the transmission buffer management unit 226 executes the second discarding process (step S704) and returns to step S701. The second discard process will be described later (see, for example, FIG. 9).

  FIG. 8 is a flowchart illustrating an example of the first discarding process performed by the transmission buffer management unit. In step S703 illustrated in FIG. 7, the transmission buffer management unit 226 performs, for example, each step illustrated in FIG. 8 as the first discard process. In FIG. 8, “target terminal ID” is identification information of a mobile terminal to be processed, and corresponds to, for example, “terminal ID” in the terminal management table 400 shown in FIG. First, the transmission buffer management unit 226 sets “1” to “target terminal ID” (step S801).

  Next, the transmission buffer management unit 226 acquires the “wireless quality state” corresponding to the current “target terminal ID” from the terminal management table 400 (see, for example, FIG. 4) (step S802). Next, the transmission buffer management unit 226 determines whether or not the “wireless quality state” acquired in step S802 is a “wireless quality deteriorated state” (step S803).

  In step S803, when the “wireless quality state” is not the “wireless quality deteriorated state” (step S803: No), the transmission buffer management unit 226 proceeds to step S805. When the “wireless quality state” is the “wireless quality deteriorated state” (step S803: Yes), the transmission buffer management unit 226 sets the “first transmission buffer usage” corresponding to the current “target terminal ID” to the terminal. Obtained from the management table 400. Then, the transmission buffer management unit 226 discards transmission data exceeding the acquired “first transmission buffer usage” from the transmission buffer for the mobile terminal corresponding to the current “target terminal ID” (step S804).

  Next, the transmission buffer management unit 226 determines whether or not the processes in steps S802 to S804 have been executed for all mobile terminals that are performing radio communication with the radio base station apparatus 220 (step S805). . When the process is not executed for all the mobile terminals (step S805: No), the transmission buffer management unit 226 increments the “target terminal ID” (step S806) and returns to step S802. When the process is executed for all the mobile terminals (step S805: Yes), the transmission buffer management unit 226 ends the series of first discard processes.

  FIG. 9 is a flowchart illustrating an example of the second discarding process performed by the transmission buffer management unit. In step S704 illustrated in FIG. 7, the transmission buffer management unit 226 performs, for example, each step illustrated in FIG. 9 as the second discarding process.

  Steps S901 to S906 shown in FIG. 9 are the same as steps S801 to S806 shown in FIG. However, in step S <b> 904, the transmission buffer management unit 226 acquires “second transmission buffer usage” corresponding to the current “target terminal ID” from the terminal management table 400. Then, the transmission buffer management unit 226 discards transmission data exceeding the acquired “second transmission buffer usage amount” from the transmission buffer for the mobile terminal corresponding to the current “target terminal ID” (step S904).

  If the process is executed for all mobile terminals in step S905 (step S905: Yes), the transmission buffer management unit 226 determines whether or not the total use amount of the transmission buffer exceeds the threshold value TH2. (Step S907). When the total usage amount is equal to or less than the threshold value TH2 (step S907: No), the transmission buffer management unit 226 ends the series of second discard processing.

  In step S907, when the total usage exceeds the threshold value TH2 (step S907: Yes), the transmission buffer management unit 226 executes a predetermined discarding process (step S908), and a series of second End the disposal process. For the discarding process in step S908, for example, discarding methods of various methods such as a method of discarding an excess amount with respect to the threshold, a method using Random Early Discard, and a method of performing these on a QoS basis can be used. As a result, when the congestion state of the transmission buffer continues, a predetermined discarding process can be executed to eliminate the congestion state.

  Thus, according to the radio base station apparatus 220 according to the second embodiment, the usage amount of each transmission buffer for each mobile terminal can be limited according to the radio quality for each transmission destination. Thereby, it is possible to preferentially discard the transmission data to the low-quality mobile terminal, suppress the influence on other mobile terminals, and improve the throughput.

  As described above, according to the wireless communication apparatus and the control method, it is possible to improve the throughput.

  For example, in the method in which a transmission buffer is fixedly assigned to each mobile terminal, the use of a certain amount of transmission buffer is guaranteed for all mobile terminals, but the unused buffer area by a mobile terminal with a small amount of communication or an unconnected mobile terminal Cannot be used. In addition, since transmission data cannot be held exceeding the transmission buffer fixed amount for each mobile terminal, resistance to burst traffic is low.

  Further, in the method of simply sharing a buffer among a plurality of mobile terminals, communication of all mobile terminals is affected when a transmission buffer overflow occurs. For example, when a mobile terminal with low downlink radio quality uses a high-rate application in the downlink direction such as streaming video, transmission data may stay in the transmission buffer due to the speed difference between the wireless interface and the wired interface. is there.

  With the method of simply sharing the buffer among a plurality of mobile terminals against the congestion state of the transmission buffer caused in this way, the transmission data to the mobile terminal having a low radio quality cannot be discarded. For this reason, the data to the mobile terminal with low radio quality continues to stay, hindering the use of the transmission buffer of the other terminal, and increasing the possibility of causing the data loss of the other terminal due to the buffer discard process when the transmission buffer is congested.

  On the other hand, according to the radio base station apparatus 220 described above, in the buffer discarding process when the transmission buffer is congested, it is possible to limit the amount of transmission buffer used according to the radio quality state for each mobile terminal. . As a result, in the case of congestion, the data of the mobile terminal whose radio quality is continuously degraded is preferentially discarded, so that the congestion of the transmission buffer caused by the mobile terminal whose radio quality is degraded is effectively prevented. Can be avoided, and the influence on the communication of other terminals can be suppressed.

  In addition, when limiting transmission buffer usage, considering mobility, etc., terminals whose radio quality has been temporarily reduced are excluded from the restriction, and only the transmission buffer usage of mobile terminals whose radio quality is continuously reduced Can be limited.

  The following additional notes are disclosed with respect to the above-described embodiments.

(Supplementary note 1) a buffer for storing each transmission data to a plurality of communication destinations;
A transmission unit that reads and wirelessly transmits transmission data stored in the buffer;
An acquisition unit for acquiring information indicating the radio quality of each of the plurality of communication destinations;
Based on the information acquired by the acquisition unit, a control unit that limits the amount of the buffer used for each of the plurality of communication destinations;
A wireless communication apparatus comprising:

(Additional remark 2) The said control part has the said radio | wireless quality higher than the said 1st communication destination of the said several communication destinations, and the upper limit of the usage-amount of the said buffer of the 1st communication destination among these communication destinations The wireless communication apparatus according to appendix 1, wherein the wireless communication apparatus is set lower than a second communication destination and discards transmission data so that a use amount of the buffer does not exceed the upper limit for each of the plurality of communication destinations.

(Supplementary note 3) The wireless communication apparatus according to supplementary note 2, wherein the control unit sets the upper limit lower for communication destinations having lower wireless quality among the plurality of communication destinations.

(Additional remark 4) The said control part sets the said upper limit according to the total amount of each transmission data stored in the said buffer, The radio | wireless communication apparatus of Additional remark 2 or 3 characterized by the above-mentioned.

(Additional remark 5) The said acquisition part acquires the information which averaged the said wireless quality in a predetermined period about each of these communication destinations, The radio | wireless as described in any one of Additional remarks 1-4 characterized by the above-mentioned. Communication device.

(Additional remark 6) The said acquisition part acquires the information which averaged the information which shows the said radio | wireless quality received in multiple times from the said communication destination about each of these communication destinations, The additional description 5 characterized by the above-mentioned. Wireless communication device.

(Appendix 7) The plurality of communication destinations are mobile terminals,
The wireless communication device according to any one of appendices 1 to 6, wherein the wireless communication device is a wireless base station device that performs wireless communication with the mobile terminal.

(Supplementary note 8) A control method in a wireless communication apparatus that includes a buffer in which transmission data to a plurality of communication destinations is stored, reads the transmission data stored in the buffer, and wirelessly transmits the data.
Obtaining information indicating the radio quality of each of the plurality of communication destinations;
Based on the acquired information, the usage amount of the buffer for each of the plurality of communication destinations is limited.
A control method characterized by that.

DESCRIPTION OF SYMBOLS 100,200 Communication system 110 Wireless communication apparatus 111 Buffer 112 Transmission part 113 Acquisition part 114 Control part 121,122 Communication destination 130 Communication apparatus 131 CPU
132 RAM
133 Non-volatile memory 134 Wireless communication interface 135 Wired communication interface 139 Bus 220 Wireless base station device 221 Base station control unit 222 Transmission path interface unit 223 Baseband processing unit 224 Wireless unit 225 PDCP layer processing unit 226 Transmission buffer management unit 227 RLC layer processing Unit 228 MAC layer processing unit 229 PHY layer processing unit 230 radio quality monitoring unit 240 access network 250 MME / SGW
260 Host IP network 300 Transmission buffer 400 Terminal management table 501 Normal state 502 Radio quality degradation state 600 table

Claims (3)

A buffer for storing each transmission data to a plurality of communication destinations;
A transmission unit that reads and wirelessly transmits transmission data stored in the buffer;
An acquisition unit for acquiring information indicating the radio quality of each of the plurality of communication destinations;
Based on the information acquired by the acquisition unit, the upper limit of the buffer usage of the first communication destination among the plurality of communication destinations is set to be wireless from the first communication destination of the plurality of communication destinations. The upper limit is set in accordance with the total amount of each transmission data stored in the buffer, the lower limit being set lower than the second communication destination having high quality, and the buffer usage amount is set to the upper limit for each of the plurality of communication destinations. A control unit that discards transmission data so as not to exceed
A wireless communication apparatus comprising: The wireless communication apparatus according to claim 1, wherein the acquisition unit acquires information obtained by averaging the wireless quality over a predetermined period for each of the plurality of communication destinations. A control method in a wireless communication apparatus comprising a buffer for storing each transmission data to a plurality of communication destinations, wherein the transmission data stored in the buffer is read and wirelessly transmitted.
Obtaining information indicating the radio quality of each of the plurality of communication destinations;
Based on the acquired information, the upper limit of the buffer usage of the first communication destination among the plurality of communication destinations is higher than that of the first communication destination among the plurality of communication destinations. The lower limit is set lower than two communication destinations, and the upper limit is set according to the total amount of each transmission data stored in the buffer, so that the usage amount of the buffer does not exceed the upper limit for each of the plurality of communication destinations. Discard data sent to
A control method characterized by that.

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