JP2003078937A - Communication system and base station for the communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication that can efficiently realize the FCS (Fast Cell Selection). SOLUTION: The communication system is provided with a plurality of base stations A103 to C105 that receive data from a data distributor 101 and can synchronize a data storage state and with a mobile station 106 that can select a base station with which the mobile station makes communication under a prescribed condition in the case of wireless communication with them. In a plurality of the base stations A103 to C105, the data storage state of the base station selected by the mobile station 106 is synchronized with the data storage state of the other base stations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system having a plurality of base stations capable of wireless communication with mobile stations,
In particular, the present invention relates to a communication system and a base station capable of dynamically selecting a base station with which a mobile station communicates.

[0002]

2. Description of the Related Art In recent years, W-CDMA, which is a third generation mobile communication system, is approaching the stage of practical application. The maximum transmission rate in W-CDMA at this practical stage is 2 Mbp.
s, but 3 gpp (Third Generati
On Partnership Project), HSDPA (High Speed Down Down) realizes downlink transmission with a maximum transmission rate of about 10 Mbps.
A technique called "link packet access" is under study. This HSDPA technology is, for example, a 3gpp document “3G TR25.950”.
According to the above, a major feature of the configuration is that high-speed control can be realized by arranging the radio channel allocation function and the retransmission control function in the base station, and the transmission buffer required for retransmission control should also be arranged in the base station. It becomes a composition.

In addition, one of the elemental technologies under consideration for HSDPA is FCS (fast cell).
selection). In this FCS, when a mobile station is in a state of being able to receive signals from a plurality of base stations or sectors, the mobile station dynamically selects a base station or sector with good reception quality in units of radio frames. This is a technology in which only the selected base station or sector transmits a radio signal. According to this, a sufficient reception quality can be expected without simultaneously transmitting signals for transmitting the same information from a plurality of base stations or sectors like in soft handover, and thus effective use of frequencies can be achieved.

FIG. 24 is an explanatory diagram showing a conventional communication system capable of FCS between base stations. In the figure, 101
Is a user data distribution device that transmits user data to a plurality of base stations, and 103 to 105 are base stations A to C and 1 respectively.
06 is a mobile station. Next, the outline of the base station selection operation will be described with reference to the drawings. The user data distribution device 101 uses FC
The same user data is transmitted to a plurality of base stations that may be selected from the mobile station 106 by S. Each of the base stations A103 to C105 stores user data in a buffer (not shown), and the mobile station 1
Send to 06.

Next, the mobile station 106 receives a plurality of base stations A103 to C1 from the received user data and broadcast signals.
Observe the reception quality of the signal from 05 and recognize the base station with the best reception quality. Next, when changing the base station with which the mobile station 106 communicates, the mobile station 106 outputs a "cell selection signal" to notify the change of the base station.

Next, the base station receiving the cell selection signal
The base station that has started transmission of user data and has not been selected stops transmission of user data.

Next, the operation of the FCS will be described with reference to the drawings.
FIG. 25 is an explanatory diagram showing a conventional FCS operation. Note that, here, the FCS between the base station A 103 and the base station B 104 will be described. First, it is assumed that the mobile station 106 communicates with the base station B104 and receives user data from the base station B104.

Next, for example, as the mobile station 106 moves, the reception quality from the base station A103 and the base station B104 changes, and the mobile station 106 receives from the base station A103 rather than the reception quality from the base station B104. When determining that the quality is better, the mobile station 106 transmits a "cell selection signal" to the base station A103.

Next, the base station A 103, which has received the "cell selection signal", starts transmitting user data, and the base station B1
04 stops transmission of user data.

Further, after that, the mobile station 106 determines that the base station B1
The mobile station 106 determines that the reception quality from 04 is better.
Similarly transmits a "cell selection signal" to the base station B104,
User data is received from the base station B104.

[0011]

However, since the conventional FCS is configured as described above, the conventional FC
When S is adopted in a communication system, it is necessary to synchronize the states of the buffers in each base station as much as possible in order to realize an efficient FCS. That is, immediately after switching the base station, user data already received from the old base station is received redundantly from the new base station, or conversely, user data last received from the old base station and first received from the new base station. It should be excluded as much as possible from the fact that untransmitted user data actually exists between the received user data and the user data.

Regarding this problem, the above-mentioned "T
R 25.950 ”, and the first
First, a method for synchronizing buffers by exchanging control signals between base stations through a network. Second,
Although there are roughly classified into two methods of solution such as a method of synchronizing buffers by receiving an uplink control signal transmitted from a mobile station by a plurality of base stations, at present, the specific solution is. Not shown.

The present invention has been made in order to solve the above problems, and obtains a communication system capable of realizing efficient FCS without duplication or omission in data transmitted by switching base stations. The purpose is to

[0014]

A communication system according to the present invention comprises a plurality of base stations formed so as to receive data from a data distribution device and synchronize their data storage states with each other, and the plurality of base stations. A mobile station capable of selecting a base station to communicate with according to a predetermined condition during wireless communication, wherein the plurality of base stations have a data storage state of a base station selected by the mobile station and a data storage state of another base station. Are to be synchronized.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner,
The plurality of base stations are connected via a network side,
A transmission control unit that determines whether the mobile station is selected based on the cell selection signal, and a buffer state synchronization signal that synchronizes the data storage state in the buffer when data is transmitted to the mobile station. Is provided.

In the communication system of the present invention, the mobile station stores the data received before transmitting the cell selection signal, and when the data received after transmitting the cell selection signal matches the stored data, One of the data is discarded.

In the communication system according to the present invention, the plurality of base stations store in advance the data discard number for synchronizing the data storage state based on the transmission delay time of the buffer state synchronization signal and the transmission data, and the mobile station selects the cell selection signal. When the data is selected by, the data corresponding to the data discard number is discarded from the buffer.

In the communication system of the present invention, the mobile station transmits the received data information for identifying the received data and the control signal indicating the reception result, and the plurality of base stations receive the control signal and receive the received data information. Based on the above, the corresponding data is discarded from the buffer.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner. Has a function of transmitting received data information for identifying and a control signal indicating a reception result, the plurality of base stations are connected via the network side, and whether or not the base station is selected by the mobile station based on the cell selection signal. A transmission control unit for determining whether or not a function to output a buffer state synchronization signal for synchronizing the data storage state in the buffer, and receiving the control signal, discarding the corresponding data from the buffer based on the received data information. And a buffer management unit having a function to perform.

In the communication system of the present invention, the mobile station transmits request data information indicating the requested data together with the cell selection signal, and the base station selected by the cell selection signal buffers before the data indicated by the request data information. The data stored in is discarded.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner. , A function of transmitting a control signal indicating the received data information and the reception result for identifying, and a function of transmitting request data information indicating the requested data together with the cell selection signal, wherein the plurality of base stations are the cell selection signals. A transmission control unit that determines whether or not the mobile station has been selected by the mobile station, a function of receiving the control signal and discarding the data identified based on the received data information from the buffer, and the data indicated by the request data information. A buffer management unit having a function of discarding the data previously stored in the buffer is provided.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner. Has a function of transmitting the received data information for identifying the control signal indicating the reception result and the reception result, a function of transmitting request data information indicating the requested data together with the cell selection signal, and the plurality of base stations are connected via the network side. Connected to each other and outputting a buffer state synchronization signal for synchronizing the data storage state in the buffer with a transmission control section that determines whether the mobile station is selected based on the cell selection signal, the control signal In response to this, the function of discarding the data identified based on the received data information from the buffer, the buffer before the data indicated by the requested data information. It is provided with a buffer management unit having a function to discard data stored in §.

A base station according to the present invention is a base station which is connected to a network of a communication system and arranged in a service area so as to be capable of wireless communication with a mobile station, and a cell selection signal from the mobile station. A transmission control unit that determines whether or not to transmit data to and from the mobile station based on the above, and a buffer state synchronization signal that synchronizes the data storage state when there is data transmission to the mobile station. And a buffer management unit for transmitting the data to the base station, the buffer management unit discards data from the buffer based on a buffer status synchronization signal from another base station via the network.

The base station of the present invention stores in advance the data discard number for synchronizing the data storage state based on the transmission delay time of the buffer state synchronization signal and the transmission data, and is selected by the cell selection signal from the mobile station. In this case, data corresponding to the number of discarded data is discarded from the buffer.

In the base station of the present invention, the buffer management section receives a control signal including received data information for identifying received data from the mobile station, and discards the corresponding data from the buffer based on the received data information. It is a thing.

A base station according to the present invention is a plurality of base stations arranged in a service area of a communication system so as to be capable of radio communication with a mobile station, and the mobile station moves based on a cell selection signal from the mobile station. A transmission control unit that determines whether or not to transmit data to and from the station, and a control signal that includes received data information that identifies received data from the mobile station, and is applicable based on the received data information. And a buffer management unit for discarding data from the buffer.

In the base station of the present invention, the buffer management unit receives the request data information transmitted from the mobile station and, when selected by the cell selection signal to the mobile station, buffers the data before the data indicated by the request data information. The data stored in is discarded.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. An embodiment of a communication system and a base station according to the present invention will be described. 1 is an explanatory diagram of a communication system according to a first embodiment of the present invention. In FIG. 1, 101 is a user data distribution device, which transmits user data 01 to a plurality of base stations. An inter-base station communication device 102 provides means for exchanging control information between a plurality of base stations. 103,10
Reference numerals 4 and 105 denote base stations A, B and C, and 106 denotes a mobile station. Reference numeral 101 denotes a communication system 107.
Included is a configuration labeled 106.

In the first embodiment, the inter-base station communication device 102 and the user data distribution device 101 are separated, but the inter-base station communication device 102 and the user data distribution device 101 may be integrated. Absent. In addition, a wired link or a wireless link may be provided between the inter-base station communication device 102 and the base stations A103 to C105.

FIG. 2 is an explanatory diagram of the base station shown in FIG. In the figure, 201 is a buffer for accumulating user data 01 to be transmitted, and 202 is a buffer management section for managing the state of the buffer 201. Reference numeral 203 denotes a transmission control unit, which is based on the cell selection signal 02 from the mobile station 106.
It is determined whether or not the user data 01 is dispensed from the buffer 201. A buffer state synchronization signal 03 is exchanged between the base stations via the inter-base station communication device 102 by the base stations A103 to C105.

Next, the operation will be described with reference to the drawings. In FIG. 1, the user data distribution device 101 derives the destination mobile station of the user data 01 received from a host network (not shown) from its header information and the like. Next, the user data distribution apparatus 101 has a plurality of base stations that may be selected when the derived destination mobile station performs FCS processing (in the first embodiment, all the base stations A103 to C105). User data 01 is broadcast to In addition, the user data distribution device 101 assigns a sequence number to the user data 01 to identify the identity of the user data 01, and broadcasts it.

Next, the inter-base station communication device 102 derives the destination base station of the buffer status synchronization signal 03 received from the base stations A103 to C105 from the header information and transfers it to the base station.

Next, the mobile station 106 observes signals from the base stations A103 to C105, which are the surrounding base stations, selects the base station with the best channel quality, and selects the base station. Signal 02 enables each of the base stations A103 to C10
Notify 5. In the first embodiment, base station B104 is selected for convenience of explanation.

Next, the operation of the base station will be described with reference to the drawings.
FIG. 3 is a flowchart showing the operation of the transmission control unit mounted in the base station in response to the cell selection signal. First, when the base stations A103 to C105 receive the cell selection signal 02 from the mobile station 106, the base stations A103 to C105 check whether or not their own stations are selected (step S301). If they are selected, the selection flags are set. ON (step S302)
If it is not selected, it is turned off (step S303). This selection flag indicates that the user data is 0.
At a transmission timing of 1, it is referred to for deciding whether to actually transmit.

FIG. 4 is a flow chart showing the data transmission operation of the transmission control unit mounted in the base station. The data transmission control portion of this transmission control unit 203 (shown in FIG. 2) is periodically activated, and whether or not the own station is selected depending on whether the selection flag is ON or OFF based on the cell selection signal 02 from the mobile station 106. It is determined whether or not (step S40
1) If the own station is selected, the buffer management unit 20
2 (shown in FIG. 2), the user data 01 is requested to be paid out, and the user data 01 is transmitted to the mobile station 106 (step S402).

FIG. 5 is a flow chart showing the operation of the buffer management section mounted in the base station. First, when the buffer management unit 202 recognizes that the user data 01 has been paid out from the buffer 201, it outputs the buffer state synchronization signal 03. In the first embodiment, as described above, since the base station B104 is selected, the buffer state synchronization signal including the sequence number of the user data 01 issued and the discard request message is output from the buffer management unit 202 of the base station B104. 03 via the inter-base station communication device 102, a peripheral base station (for example, base station A1
03 or the base station C105) (step S50)
1).

FIG. 6 is a flow chart showing another operation of the buffer management section mounted in the base station. When receiving the buffer state synchronization signal 03 via the inter-base station communication device 102, the base stations A103 to C105 manage the buffer 201 based on the contents of the buffer state synchronization signal 03. For example, when the base stations A103 and C105 receive the buffer synchronization signal 03 including the discard request message from the base station B104 and the sequence number of the user data 01, the base stations A103 and C105 correspond to the sequence numbers included in the message from the respective buffers 201. The user data 01 to be deleted is deleted (step S601).

Next, a series of operations regarding FCS between the mobile station and a plurality of base stations will be described with reference to the drawings. Figure 7
It is a sequence diagram which shows a series of operation | movement regarding FCS between a mobile station and several base stations. Here, initially, the mobile station 1
It is assumed that 06 has received the user data 01 from the base station A 103.

Next, the base station A 103 sends the user data 0
Each time 1 is paid out from the buffer 201 in the base station A 103, the base station B 10 is transmitted via the inter-base station communication device 102.
4, the buffer state synchronization signal 03 (including the discard request message and the sequence number of the user data 01) is transmitted (points a and b in FIG. 7).

In the first embodiment, the base station A1
03 outputs the buffer status synchronization signal 03 of the message contents for discarding the sequence numbers 1 and 2 of the user data 01 at the point a in FIG. 7, and the user data 01 at the point b in FIG.
The buffer state synchronization signal 03 of the message contents for discarding the sequence number 3 of is output.

Next, the inter-base station communication device 102 (shown in FIG. 1) transmits the buffer state synchronization signal 03 to the base station B104.

Next, the base station B104 having received the buffer status synchronization signal 03 discards the user data 01 corresponding to the sequence number indicated by the discard request message from the buffer 201 (points a and b in FIG. 7).

In the first embodiment, the base station B1
04 receives the buffer state synchronization signal 03 indicating that the sequence numbers 1 and 2 of the user data 01 are discarded at the point a in FIG. 7, discards the user data of sequence numbers 1 and 2, and b in FIG. At this point, the buffer state synchronization signal 03 for discarding the sequence number 3 of the user data 01 is received, and the user data of the sequence number 3 is discarded.
As a result, the base station A 103 and the base station B 104 have the same contents of the user data 01 stored in the respective buffers 201, and the states of the buffer 201 between the base stations can be synchronized.

Next, when the mobile station 106 determines that the reception quality from the base station B104 is better than that of the base station A103 due to factors such as the movement, it notifies that the base station B104 is selected. A cell selection signal 02 to be transmitted is transmitted (point c in FIG. 7).

Next, the base station B104 receives the cell selection signal 02 from the mobile station 106, executes the operation in response to the cell selection signal 02 shown in FIG. 3, and sets the selection flag because its own station is selected. When turned on, the user data 01 is transmitted to the mobile station 106 as in the data transmission operation shown in FIG.
When transmitting the user data 01, the base station B10
No. 4 is synchronized with the base station A 103 in the storage state of the user data 01 in the buffer 201, so that there is no duplication or omission of sequence numbers, and the sequence number consecutive to the sequence number 3 already transmitted by the base station A 103. 4 data is transmitted.

Also, the base station B104 uses the user data 0
1 is transmitted to the mobile station 106, and the buffer state synchronization signal 03 (including the discard request message and the sequence number 4 of the user data 01) is sent to the base station A 103 via the inter-base station communication device 102 (shown in FIG. 1). Is transmitted (point d in FIG. 7).

Next, the base station A 103 receives the buffer status synchronization signal 03 via the inter-base station communication device 102, and outputs the user data 01 corresponding to the sequence number 4 indicated by the discard request message from the buffer 201. Discard (point d in FIG. 7).

As described above, according to the communication system according to the first embodiment, the user data 01 from the data distribution device 101 is received and the buffers 2 of the two are mutually exchanged.
A plurality of base stations A103-C105 and a plurality of base stations A103-C which are formed so as to be able to synchronize the data storage state of 01.
A plurality of base stations A103 to C1 are provided with a mobile station 106 that can be switched so as to communicate with a base station having a predetermined condition, that is, the best channel quality in wireless communication with 105.
No. 05 synchronizes the data storage state of the buffer 201 of the base station with which the mobile station 106 communicates with the data storage state of another base station, so that efficient FCS can be performed and the base station can be switched by the FCS. However, it is possible to prevent duplication or omission in the user data 01 transmitted to the mobile station,
The continuity can be maintained and the wireless line can be effectively used.

Further, when synchronizing the data storage states among a plurality of base stations, control signals such as the buffer state synchronization signal 03 are transmitted or exchanged through the network side such as the inter-base station communication device 102, so that they are relatively reliable. The cost can be kept low as well as the cost performance can be improved.

Further, according to the base station of the first embodiment, a transmission control section 203 for judging whether or not data is transmitted to and from the mobile station 106 based on the cell selection signal 02 from the mobile station 106. , A buffer management unit 202 that transmits a buffer status synchronization signal 03 for synchronizing the data storage status to another base station when data is transmitted to the mobile station 106. Since the data is discarded from the buffer 201 based on the buffer state synchronization signal 03 including the sequence number of the transmitted data from another base station via the communication device 102, the data storage states of a plurality of base stations can be synchronized. it can.

In the first embodiment, the transmission timing of the buffer state synchronization signal 03 including the discard request message is set to the time when the user data 01 is transmitted from the buffer 201, but the transmission between the base station and the mobile station is performed. When the retransmission control is being performed, the discard message may be transmitted at the time when the delivery of the user data to the mobile station is confirmed.

The communication system according to the first embodiment is particularly effective when the transmission delay in inter-base station communication is sufficiently smaller than one frame interval in terms of time.

Embodiment 2. Another aspect of the communication system according to the present invention will be described. Here, an aspect of a communication system that is particularly effective when the transmission delay in inter-base station communication is not negligible as compared with one frame interval is shown. The overall configuration of the communication system according to the second embodiment is the same as that of the communication system shown in FIG.

Next, the operation will be described with reference to the drawings. Figure 8
It is a sequence diagram which shows a series of operation | movement regarding FCS between a mobile station and several base stations. In FIG. 8, the same symbols as those in FIG. 7 indicate the same or corresponding parts, and the description thereof will be omitted. Here, it is assumed that the mobile station 106 initially receives the user data 01 from the base station A 103. Next, the base station A1
03, the inter-base station communication device 102 (shown in FIG. 1) is sent to the base station B 104 every time the user data 01 is sent out from the buffer 201 (shown in FIG. 2) in the base station A 103 and transmitted to the mobile station 106. The buffer state synchronization signal 03 (including the discard request message and the sequence number of the user data 01) is sent via the (steps a and b in FIG. 8).

Next, the inter-base station communication device 102 (shown in FIG. 1) transmits the buffer state synchronization signal 03 to the base station B104.

Next, the base station B 104 which has received the buffer state synchronization signal 03 discards the user data 01 corresponding to the sequence number indicated by the discard request message from the buffer 201, but the base station A 103 and the base station B 103
When the transmission delay in communication between 104 is not negligible as compared with the one-frame interval, as shown in FIG. 8, the discarding of the sequence numbers 1, 2, and 3 of the user data 01 is not completed at points a and b, respectively, and immediately. The data storage status of may not be synchronized.

In such a synchronization state, the cell selection signal 0 for notifying that the base station B104 is selected from the mobile station 106
2 is transmitted (point c in FIG. 8), the base station B104
From the sequence number 3 of the user data 01 to the mobile station 106
8 (point d in FIG. 8), the mobile station 106 may receive the same data (the mobile station 106 in FIG. 8).
Received the data of sequence number 3 twice).

However, the mobile station 106 has a data comparison unit (not shown), and discards the same user data 01 when it is received. For example, the data comparison unit outputs the cell selection signal 02 in particular. The sequence numbers and contents of the received data immediately before and after the output are compared, and if they match, one of the received data is discarded.

As described above, according to the communication system according to the second embodiment, the mobile station 106 sets the cell selection signal 0
The sequence number of the user data 01 before outputting 2 is stored, and when it matches the received data immediately after the cell selection signal is transmitted, one of them is discarded. Therefore, the transmission delay in communication between base stations is 1 Efficient FCS can be performed even if it cannot be ignored compared to the frame interval.
Even when there is some synchronization deviation due to the transmission delay of the inter-base station communication at the time of switching the base station by the, the continuity of the user data 01 transmitted to the mobile station 106 can be maintained, and the wireless line can be effectively used. .

Embodiment 3. Another aspect of the communication system according to the present invention will be described. Here, another aspect of the communication system which is effective when the transmission delay in the communication between base stations is not negligible as compared with the one-frame interval is shown. The overall configuration of the communication system according to the third embodiment is the same as that of the communication system shown in FIG.

Next, the operation will be described with reference to the drawings. Figure 9
It is a sequence diagram which shows a series of operation | movement regarding FCS between a mobile station and several base stations. In FIG. 9, the same symbols as those in FIG. 7 or 8 indicate the same or corresponding parts, and the description thereof will be omitted. Here, it is assumed that the mobile station 106 initially receives the user data 01 from the base station A 103. next,
The base station A103 sends the user data 01 to the base station A103.
Each time it is delivered from the internal buffer 201 (shown in FIG. 2) and transmitted to the mobile station 106, the buffer state synchronization signal 03 (discarded) is sent to the base station B 104 via the inter-base station communication device 102 (shown in FIG. 1). Request message and user data 0
(Including a sequence number of 1) (a and b in FIG. 9)
point).

Here, base station A103 and base station B104
When the transmission delay in the communication between the two is not negligible as compared with the one-frame interval, the base station B is used as in the second embodiment.
In 104, the discarding of the sequence numbers 1, 2, and 3 of the user data 01 is not completed, and the immediate data storage state cannot be synchronized (points a and b in FIG. 9).

Next, the operation of the base station after the cell selection signal 02 for notifying the selection of the base station B104 from the mobile station 106 is transmitted (point c in FIG. 9) will be described with reference to the drawings.
10 and 11 are flowcharts showing the data discarding and data transmitting operations when the base station receives the cell selection signal. 10 and 11, the same reference numerals as those in FIG. 3 or FIG. In FIG. 10, base stations A103 to C105 (see FIG.
When receiving the cell selection signal 02 from the mobile station 106, it checks whether or not its own station is selected (step S901), and if selected, turns on the selection flag (step S902). ), And when its own station is selected, the M user data 01 from the head of the buffer 201 (shown in FIG. 2) are discarded (step S).
903). In the third embodiment, M is set to 1, and the base station B104 discards the sequence number 2 of the user data 01 as shown in FIG. The number M of discarded data is a value determined from the number N of transmission user data in one frame and the inter-base station communication delay T. Also, each base station sets the selection flag to O when its own station is not selected.
Set to FF (step S904).

Next, as shown in FIG. 11, the base station B10
4 determines whether or not the own station is selected depending on whether the selection flag is ON or OFF (step S1001), and when the own station is selected, the buffer management unit 202 (FIG. 2).
(Shown in FIG. 2), requesting payout of N user data 01,
The user data 01 is transmitted to the mobile station 106 (step S1002). In this Embodiment 3, the base station B104
Transmits the user data 01 having the sequence number 3 to the mobile station 10
Send to 6.

As described above, according to the communication system according to the third embodiment, the transmission delay in the inter-base station communication is taken into consideration, and when the own station is selected, a predetermined number of head users in the buffer are selected. Since the data is discarded, a plurality of base stations A10
In 3 to C105, since the data storage state of the buffer 201 of the base station that is a communication partner of the mobile station 106 and the data storage state of another base station are synchronized, efficient FCS can be performed,
Even if the base station is switched by the FCS, the mobile station 106
It is possible to prevent duplication or omission of the user data 01 transmitted to the user, maintain its continuity, and effectively use the wireless line.

Further, according to the base station of the third embodiment, the mobile station 106 stores in advance the data discard number for synchronizing the data storage state based on the transmission delay time of the buffer state synchronization signal 03 and the user data. Since the data corresponding to the number of discarded data is discarded from the buffer 201 when the cell selection signal 02 is selected, the data storage states of a plurality of base stations can be synchronized.

Fourth Embodiment Another aspect of the communication system according to the present invention will be described. Compared to the communication system shown in FIG. 1, the communication system according to the fourth embodiment particularly has an inter-base station communication device 1 when synchronizing data storage states between base stations.
02 (shown in FIG. 1) is not used, but an uplink control signal from the mobile station is used. FIG. 12 is an explanatory diagram showing a communication system according to the fourth embodiment, and FIG. 13 is an explanatory diagram of the base station shown in FIG. 12 and 13, the same reference numerals as those in FIG. 1 or 2 indicate the same or corresponding parts, and the description thereof will be omitted. A retransmission control signal 1201 is transmitted from the mobile station 106 to all related base stations.

Next, the operation will be described with reference to the drawings. As shown in FIG. 12, the mobile station 106 includes the base stations A103 to C in the vicinity.
The signal from 105 is observed, the base station with the best channel quality is selected, and the cell selection signal 02 for selecting the base station is notified to each base station. In addition, the mobile station 106 performs retransmission control (Auto Repeat reQueue) with each base station.
st control) is performed to notify each base station of a retransmission control signal 1201 indicating successful reception or unsuccessful reception of the downlink user data 01.

Next, the operation will be described with reference to the drawings. 14
6 is a flowchart showing the operation of the buffer management unit of the base station. Base stations A103 to C105 (shown in FIG. 12)
When receiving the reception success signal (with the sequence number of the user data 01) included in the retransmission control signal 1201 from the mobile station 106, discards the corresponding user data 01 in the buffer 201 (step S1401).

Next, the operation will be described with reference to the drawings. Figure 15
FIG. 4 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations. In FIG. 15, FIG.
The same reference numerals as in FIG. 9 indicate the same or corresponding parts, and the description thereof will be omitted. Here, initially, the mobile station 106 is the base station A 103.
It is assumed that the user data 01 is received from.

Next, the mobile station 106 receives the sequence number 1 of the user data 01 from the base station A 103 (see FIG. 15).
Then, a retransmission control signal 1201 (indicated by 1ACK in FIG. 15) indicating successful reception of sequence number 1 is transmitted to each base station (point b in FIG. 15). In addition, the mobile station 10
6 receives the sequence numbers 2 and 3 of the user data 01 from the base station A 103 (point c in the figure), and the retransmission control signal 1201 indicating successful reception of the sequence numbers 2 and 3 (FIG. 15).
(Indicated by a few ACKs therein) to each base station (see FIG. 15).
Middle, d point).

Next, base station A103 and base station B10
4 receives the retransmission control signal 1201 (indicated by 1ACK in FIG. 15) and discards the corresponding sequence number 1 from the buffer 201 (shown in FIG. 13) as shown in FIG. 14 based on the signal. In addition, the base station A 103 and the base station B 104 transmit the retransmission control signal 1201 (2, 3 in FIG. 15).
(Indicated by ACK), the corresponding sequence numbers 2 and 3 are discarded from the buffer 201 based on the signal.

Next, when the mobile station 106 transmits a cell selection signal 02 notifying that the base station B104 is selected (point e in FIG. 15), the base station B104 sets the sequence number 4 of the user data 01 to the mobile station. To 106.

Next, the mobile station 106 receives the sequence number 4 of the user data 01 from the base station B 104 (see FIG. 15).
(Point f in the middle), and a retransmission control signal 1201 (indicated by 4ACK in FIG. 15) indicating successful reception of sequence number 4 is transmitted to each base station (point g in FIG. 15).

Next, base station A103 and base station B10
4 receives the retransmission control signal 1201 (indicated by 4ACK in FIG. 15) and discards the corresponding sequence number 4 from the buffer 201 based on the signal.

As described above, according to the communication system of the fourth embodiment, each of the base stations A103 to C105
Based on the retransmission control signal 1201 from the mobile station 106, the data storage state of the buffer 201 is updated and synchronized. Therefore, since the data storage states of the buffers of all the base stations are always the same, efficient FCS can be performed, and even if the base station is switched by the FCS, the user data 01 transmitted to the mobile station 106 is duplicated or omitted. Can be prevented, its continuity can be maintained, and the wireless line can be effectively used.

According to the base station of the fourth embodiment,
A transmission control unit 203 that determines whether or not to perform data transmission with the mobile station 106 based on the cell selection signal 02 from the mobile station 106, and received data information that identifies received data from the mobile station 106. The buffer management unit 202 that receives the reproduction control signal 1201 that is a control signal containing the received data and discards the corresponding data from the buffer 201 based on the received data information is provided, so that the data storage state of each base station can be synchronized. it can. Furthermore, since the user data that can be correctly received by the mobile station 106 is discarded from the transmission buffer, the reliability of data transmission can be improved.

Embodiment 5. Another aspect of the communication system according to the present invention will be described. In short, the communication system according to the fifth embodiment is a combination of the method for synchronizing the data storage state of the communication system shown in FIG. 1 and the method for synchronizing the data storage state of the communication system shown in FIG. 16 is an explanatory diagram showing a communication system according to the fifth embodiment, and FIG. 17 is an explanatory diagram of the base station shown in FIG. 16 or 17, the same reference numerals as those in FIG. 1, FIG. 2, FIG. 12 or FIG.

Next, the operation will be described with reference to the drawings. FIG.
FIG. 4 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations. Here, it is assumed that the mobile station 106 initially receives the user data 01 from the base station A 103.

Next, the base station A 103 sends the user data 0
When the sequence number 1 of 1 is transmitted to the mobile station 106, the buffer state synchronization signal 03 (the discard request message and the sequence number of the user data 01 is transmitted to the base station B 104 via the inter-base station communication device 102 (shown in FIG. 16). 1) is transmitted (point a in FIG. 18).

Next, the mobile station 106 receives the sequence number 1 of the user data 01 from the base station A 103 (see FIG. 18).
Then, a retransmission control signal 1201 (indicated by 1ACK in FIG. 18) indicating successful reception of sequence number 1 is transmitted to each base station (point b in FIG. 18).

Next, each base station receiving the retransmission control signal 1201 operates as shown in FIG. 14 and discards the user data of sequence number 1. Here, the base station B104
When the retransmission control signal 1201 (indicated by 1ACK in FIG. 18) for the packet does not reach due to communication error or the like, the base station B10
4 cannot discard the user data 01 having the sequence number 1 based on the retransmission control signal 1201.

However, the base station B 104 is connected to the base station A via the inter-base station communication device 102 (shown in FIG. 16).
Since the buffer state synchronization signal 03 from 103 is transmitted, the base station B104 can operate as shown in FIG. 6 to discard the user data 01 having the sequence number 1, and the base station A103 and the base station B104 can receive the same. The data storage status can be synchronized.

Further, the base station A 103 uses the user data 0
When the sequence numbers 2 and 3 of 1 are transmitted to the mobile station 106, the buffer status synchronization signal 03 (the discard request message and the user data 01 of the discard data and the user data 01 is sent to the base station B 104 via the inter-base station communication device 102 (shown in FIG. 16). (Including sequence numbers 2 and 3) is transmitted (point c in FIG. 18).

Next, the mobile station 106 receives the sequence numbers 2 and 3 of the user data 01 from the base station A 103 (point c in FIG. 18) and the retransmission control signal 1201 indicating the successful reception of the sequence numbers 2 and 3. (Indicated by 2,3 ACK in FIG. 18) is transmitted to each base station (point d in FIG. 18).

Next, each base station receiving the retransmission control signal 1201 operates as shown in FIG. 14 and discards the user data of sequence numbers 2 and 3. As shown in FIG. 18, the previous retransmission control signal 1201 (1ACK in FIG. 18)
(Indicated by), but did not reach the base station B104,
Since the base station B 104 has discarded the data of sequence number 1 by the buffer state synchronization signal 03, the base station A 1
It can be seen that the data storage states of 03 and B104 are synchronized. Note that the description of the subsequent operation (the operation after the cell selection signal 02 is transmitted from the mobile station 106 at point e in FIG. 18) is omitted.

As described above, according to the communication system of the fifth embodiment, a plurality of base stations A103 to C105 are provided.
When synchronizing the data storage state between the base station and the base station communication device 10
The method of transmitting and exchanging via the network side such as 2 and the method of updating and synchronizing the data storage state based on the uplink control signal such as the retransmission control signal 1201 from the mobile station 106 are used in combination. Therefore, it is possible to solve the problem that occurs when the transmission delay in the inter-base station communication is not negligible as compared with the one-frame interval, or when the retransmission control information 1201 cannot be received by the base station due to a failure in the wireless section, and the wireless line is stable. In the existing state, the buffer synchronization via the radio enables high-speed synchronization, and the reliable signal transmission via the network enables the synchronization, so that the data storage state between the base stations can be reliably synchronized at a higher speed. Therefore, efficient FCS can be realized,
Even if the base station is switched by the FCS, the mobile station 106
It is possible to prevent duplication or omission of the user data 01 transmitted to the user, maintain its continuity, and effectively use the wireless line.

According to the base station of the fifth embodiment,
A transmission control unit 203 that determines whether or not to perform data transmission with the mobile station 106 based on the cell selection signal 02 from the mobile station 106, and a data storage state when the data transmission to the mobile station 106 is performed. Function for transmitting buffer status synchronization signal 03 for synchronization to another base station, mobile station 106
Receiving a reproduction control signal 1201 which is a control signal including received data information for identifying the received data from the buffer 20.
Since the buffer management unit 202 having a function of discarding the data from the first base station 1 is provided, the buffer 201 based on the buffer state synchronization signal 03 including the sequence number of the transmitted data from another base station via the inter-base station communication device 102. Data is discarded, and the corresponding data is discarded from the buffer 201 based on the received data information, so that the data storage state of each base station can be synchronized. further,
Since the user data correctly received by the mobile station 106 is discarded from the transmission buffer, the reliability of data transmission can be improved.

Sixth Embodiment Another aspect of the communication system according to the present invention will be described. Here, another aspect of the communication system which is particularly effective when the transmission delay in the communication between base stations is not negligible as compared with the one-frame interval is shown. The overall configuration of the communication system according to the sixth embodiment is the same as that of the communication system shown in FIG.

Next, the operation will be described with reference to the drawings. FIG. 19
FIG. 4 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations. In FIG.
The same reference numerals as in FIG. 9, FIG. 15 or FIG. Here, initially, the mobile station 10
It is assumed that 6 receives the user data 01 from the base station A 103. Next, the base station A103 pays out the user data 01 from the buffer 201 (shown in FIG. 2) in the base station A103 and transmits it to the mobile station 106, and the base station B1
A buffer status synchronization signal 03 (including the discard request message and the sequence number of the user data 01) is sent to the communication terminal 04 via the inter-base station communication device 102 (shown in FIG. 1) (points a and b in FIG. 19). ).

Here, base station A 103 and base station B 104
If the transmission delay in the communication between the frames is not negligible as compared with the one-frame interval, the base station B104 does not complete the discarding of the sequence numbers 1, 2, and 3 of the user data 01, as in the above-described second and third embodiments. , Immediate data storage status cannot be synchronized.

Next, when the mobile station 106 determines that the channel quality with the base station B104 is better than that with the base station A103, it sends a cell selection signal 02 notifying that the base station B104 is selected. It is transmitted (point c in FIG. 19). Here, the mobile station 106 obtains the sequence number (sequence number 4 in this embodiment) expected to be received next based on the sequence number of the user data 01 already received, and the sequence number and the cell selection signal 02. To send.

Next, the operation of the base station after receiving the cell selection signal 02 will be described with reference to the drawings. 20 and 21 are flowcharts showing the data discarding and data transmitting operations when the base station receives the cell selection signal. In FIG. 20, the base stations A103 to C105 (shown in FIG. 1) check whether their own station is selected (step S20).
01), the selection flag is turned ON (step S2002) when selected, and the sequence number to be transmitted next is notified to the buffer management unit 202 (shown in FIG. 2) when the own station is selected. Yes (step S200
3). In addition, each base station turns off the selection flag when its own station is not selected (step S200).
4).

Next, the buffer management unit 2 of the base station B104
When receiving the sequence number to be transmitted next from the transmission control unit 203 (shown in FIG. 2), the 02 deletes the data before the sequence number from the buffer 201 (step S2101). In this Embodiment 6, since the notified sequence number is "4", the base station B104 discards the data of sequence number 3 and earlier.

Next, the base station B 104 operates as shown in FIG. 4 and transmits the user data 01 having the sequence number 4 to the mobile station 106. Also, the buffer state synchronization signal 0
3 is transmitted to the inter-base station communication device 102 (in FIG. 19, d
point).

As described above, according to the communication system of the sixth embodiment, when the local station receives the selected cell selection signal, the data before the sequence number expected to be transmitted next is discarded. Therefore, even if there is a transmission delay during inter-base station communication, efficient FCS can be performed, and duplication of user data 01 transmitted to mobile station 106 after switching of base stations by FCS can be prevented. The continuity can be maintained and the wireless line can be effectively used.

According to the base station of the sixth embodiment,
When selected by the cell selection signal 02 including the request data information transmitted from the mobile station 106, the data stored in the buffer 201 before the data indicated by the request data information is discarded, so that it is transmitted during the inter-base station communication. Even if there is a delay and the arrival of the buffer status synchronization signal 03 is delayed, the mobile station 10
6 can be synchronized with the data storage state of the base station that transmitted the data to the mobile station 106 immediately before.

Seventh Embodiment Another aspect of the communication system according to the present invention will be described. The overall configuration of the communication system according to the seventh embodiment is the same as that of the communication system shown in FIG.

Next, the operation will be described with reference to the drawings. FIG. 22
FIG. 4 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations. In FIG. 22, FIG.
The same reference numerals as in FIG. 9, FIG. 15, FIG. 18 or FIG. Here, it is assumed that the mobile station 106 initially receives the user data 01 from the base station A 103.

Next, the mobile station 106 receives the sequence number 1 of the user data 01 from the base station A 103 (see FIG. 22).
Then, a retransmission control signal 1201 (indicated by 1ACK in FIG. 22) indicating successful reception of the sequence number 1 is transmitted to each base station (point b in FIG. 22). In addition, the mobile station 10
6 receives the sequence numbers 2 and 3 of the user data 01 from the base station A 103 (point c in FIG. 22), and the retransmission control signal 1201 (2, 3 ACK in FIG. 22) indicating the successful reception of the sequence numbers 2 and 3. Is transmitted to each base station (point d in FIG. 22).

Next, base station A 103 and base station B 104
Receives a retransmission control signal 1201 (indicated by 1ACK in FIG. 22) and discards the corresponding sequence number 1 from the buffer 201 (shown in FIG. 13) as shown in FIG. 14 based on the signal. Also, the base station A 103 receives the retransmission control signal 1201 (indicated by 2 and 3 ACK in FIG. 22), and based on the signal, the corresponding sequence numbers 2 and 3
Is discarded from the buffer 201. Here, the base station B10
4 retransmission control signal 1201 (2, 3A in FIG. 22)
(Indicated by CK) does not reach due to a communication error or the like, the base station B104 cannot discard the user data 01 of sequence numbers 2 and 3 based on the retransmission control signal 1201.

However, the mobile station 106 notifies the cell selection signal 0 which notifies that the base station B 104 is selected as the communication partner.
When transmitting 2, the sequence number expected to be received next based on the sequence number of the user data 01 already received (sequence number 4 in this embodiment)
, And transmits the sequence number and cell selection signal 02 (point e in FIG. 22).

Next, the base station B104 which has received the cell selection signal 02 operates as shown in FIGS. 20 and 21,
The selection flag is turned on, and the buffer management unit 202 (see FIG.
The sequence number to be transmitted next is notified to ().

Next, the buffer management unit 2 of the base station B104
02 receives the sequence number to be transmitted next from the transmission control unit 203 (shown in FIG. 13), discards the data before the sequence number from the buffer 201 (in the seventh embodiment, the notified sequence number is Since it is "4", the data before the sequence number 3 is discarded).

Next, the base station B104 operates as shown in FIG. 4 to transmit the user data 01 of sequence number 4 to the mobile station 106 (point f in FIG. 22).

As described above, according to the communication system according to the seventh embodiment, the base stations A103 to C105 receive the cell selection signal 02 including the sequence number to be transmitted next from the mobile station 106 and select their own stations. When the selected cell selection signal 02 is received, the data before the sequence number to be transmitted next is discarded, so that there is a temporary failure in the wireless section and there is an uplink like the retransmission control signal 1201 from the mobile station 106. Even if the control signal does not reach the base station, efficient FCS can be performed, and duplication of the user data 01 transmitted to the mobile station 106 after the base station is switched by the FCS is prevented from occurring and its continuity is maintained. Therefore, it is possible to effectively use the wireless line.

According to the base station of the seventh embodiment,
A reproduction control signal 1201 which is a control signal including received data information for identifying received data from the mobile station 106.
In response to the received data information, the function of discarding the corresponding data from the buffer 201, when the cell selection signal 02 including the request data information transmitted from the mobile station 106 is selected, Since the mobile station 106 has a function of discarding the data stored in the buffer 201, even if there is an abnormality in the wireless section and the reproduction control signal 1201 does not reach the base station temporarily and the synchronization of the data storage state is delayed, When transmitting data, it can be synchronized with at least the data storage state of the base station that has transmitted data to the mobile station 106 immediately before.

Eighth Embodiment Another aspect of the communication system according to the present invention will be described. The communication system according to the eighth embodiment particularly transmits the sequence number to be transmitted next from the mobile station together with the cell selection signal to the method for synchronizing the data storage state of the communication system shown in FIG. It will make the synchronization more reliable. The overall configuration of the communication system according to the eighth embodiment is the same as that of the communication system shown in FIG. 16, and therefore illustration and description thereof will be omitted.

Next, the operation will be described with reference to the drawings. FIG. 23
FIG. 4 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations. Here, it is assumed that the mobile station 106 initially receives the user data 01 from the base station A 103.

Next, the base station A 103 sends the user data 0
When the sequence number 1 of 1 is transmitted to the mobile station 106, the buffer state synchronization signal 03 (the discard request message and the sequence number of the user data 01 is transmitted to the base station B 104 via the inter-base station communication device 102 (shown in FIG. 16). 1 is included) (point a in FIG. 23).

Next, the mobile station 106 receives the sequence number 1 of the user data 01 from the base station A 103 (see FIG. 23).
Then, a retransmission control signal 1201 (indicated by 1ACK in FIG. 23) indicating successful reception of sequence number 1 is transmitted to each base station (point b in FIG. 23).

Next, each base station receiving the retransmission control signal 1201 operates as shown in FIG. 14 and discards the user data of sequence number 1. Here, the base station B104
When the retransmission control signal 1201 (indicated by 1ACK in FIG. 23) to the base station B10 does not reach due to a communication error or the like, the base station B10
4 cannot discard the user data 01 having the sequence number 1 based on the retransmission control signal 1201.

However, the base station B 104 is connected to the base station A via the inter-base station communication device 102 (shown in FIG. 16).
Since the buffer state synchronization signal 03 from 103 is transmitted, the base station B104 can operate as shown in FIG. 6 to discard the user data 01 having the sequence number 1, and the base station A103 and the base station B104 can receive the same. The data storage status can be synchronized.

Further, the base station A 103 uses the user data 0
When the sequence numbers 2 and 3 of 1 are transmitted to the mobile station 106, the buffer status synchronization signal 03 (the discard request message and the user data 01 of the discard data and the user data 01 is sent to the base station B 104 via the inter-base station communication device 102 (shown in FIG. 16). (Including sequence numbers 2 and 3) (point c in FIG. 23).

Next, the mobile station 106 receives the sequence numbers 2 and 3 of the user data 01 from the base station A 103 (point c in FIG. 23), and the retransmission control signal 1201 indicating the successful reception of the sequence numbers 2 and 3. (Indicated by 2,3 ACK in FIG. 23) is transmitted to each base station (point d in FIG. 23).

Next, the base station A 103 transmits the retransmission control signal 1
201 (indicated by 2 and 3 ACK in FIG. 23) is received, and the corresponding sequence numbers 2 and 3 are similarly discarded from the buffer 201. Here, when the retransmission control signal 1201 (indicated by 2 and 3 ACK in FIG. 23) to the base station B 104 does not reach due to a communication error or the like, the base station B 104 transmits the sequence numbers 2 and 3 based on the retransmission control signal 1201. User data 01 cannot be discarded.

However, the mobile station 106 sends the cell selection signal 0 which notifies that the base station B104 is selected as the communication partner.
When transmitting 2, the sequence number expected to be received next based on the sequence number of the user data 01 already received (sequence number 4 in this embodiment)
, And transmits the sequence number and cell selection signal 02 (point e in FIG. 23).

Next, the base station B 104 which has received the cell selection signal 02 operates as shown in FIGS. 20 and 21,
The selection flag is turned on, and the buffer management unit 202 (see FIG.
The sequence number to be transmitted next is notified to ().

Next, the buffer management unit 2 of the base station B104
When receiving the sequence number to be transmitted next from the transmission control unit 203 (shown in FIG. 17), 02 discards the data before the sequence number from the buffer 201 (in the eighth embodiment, the notified sequence number is “ 4 ”, the data before the sequence number 3 is discarded).

Next, the base station B104 operates as shown in FIG. 4, and transmits the user data 01 having the sequence number 4 to the mobile station 106 (point f in FIG. 23).

As described above, according to the communication system of the eighth embodiment, when synchronizing the data storage states among a plurality of base stations, a control signal such as the buffer state synchronization signal 03 is transmitted to the inter-base station communication device 102. Such as transmission and exchange via the network side such as the mobile station 10
6 is combined with the method of updating and synchronizing the data storage state based on the retransmission control signal 1201 from the mobile station 106, and the base station receives the cell selection signal 02 including the sequence number to be transmitted next from the mobile station 106, and receives its own station. When the cell selection signal 02 in which is selected is received, the data before the sequence number to be transmitted next is discarded, so that the transmission delay in the inter-base station communication cannot be ignored compared to one frame interval, or Retransmission control information 120 due to failure
1 can not be received by the base station, or a problem that occurs when an uplink control signal such as the retransmission control signal 1201 from the mobile station does not reach the base station due to a temporary failure in the wireless section can be solved. When the line is stable, high-speed synchronization is possible by buffer synchronization via wireless, and reliable signal transmission can be performed via the network to synchronize the data storage state between base stations more reliably at higher speed. it can. Therefore, an efficient FCS can be realized, and even if the base station is switched by the FCS, the mobile station 1
It is possible to prevent duplication or omission in the user data 01 transmitted to the network 06, and to maintain the continuity of the user data 01.
Effective use of wireless lines can be achieved.

According to the base station of the eighth embodiment,
A function of discarding data from the buffer 201 based on the buffer status synchronization signal 03 including the sequence number of the transmitted data from another base station via the inter-base station communication device 102, and identifying the received data from the mobile station 106. Playback control signal 1 which is a control signal including received data information
A function of receiving 201 and discarding corresponding data from the buffer 201 based on the received data information, the mobile station 106.
Cell selection signal 02 including request data information transmitted from
When it is selected, the data stored in the buffer 201 before the data indicated by the request data information is discarded, so that the data storage state of each base station can be reliably synchronized.

[0123]

According to the communication system of the present invention, a plurality of base stations are formed which receive data from a data distribution device and are capable of synchronizing their data storage states with each other. Equipped with a mobile station capable of selecting a base station to communicate with depending on conditions, the data storage state of a plurality of base stations is synchronized with the data storage state of the base station selected by the mobile station. FCS is possible,
Even if the base station is switched by the FCS, the continuity of the data transmitted to the mobile station can be maintained, and the wireless line can be effectively used.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner,
A plurality of base stations are connected via the network side, a transmission control unit that determines whether a mobile station is selected based on a cell selection signal, and data storage in a buffer when data is transmitted to the mobile station. Since the buffer management unit that outputs the buffer status synchronization signal for synchronizing the status is provided, the data storage status can be synchronized with a simple configuration.

In the communication system of the present invention, the mobile station stores the data received before transmitting the cell selection signal, and if the data received after transmitting the cell selection signal matches the stored data, one of the Since the data is discarded, even if there is some synchronization deviation due to the transmission delay of communication between base stations,
The continuity of the data transmitted to the mobile station can be maintained, and the wireless line can be effectively used.

In the communication system of the present invention, the plurality of base stations store in advance the data discard number for synchronizing the data storage state based on the transmission delay time of the buffer state synchronization signal and the transmission data, and the mobile station selects the cell selection signal. Since the data corresponding to the number of discarded data is discarded from the buffer when selected by, efficient FCS can be performed and the continuity of the data transmitted to the mobile station is maintained even if the base station is switched by the FCS. It is possible to effectively use the wireless line.

In the communication system of the present invention, the mobile station transmits the received data information for identifying the received data and the control signal indicating the reception result, and the plurality of base stations receive the control signal and based on the received data information. Since the corresponding data is discarded from the buffer, efficient FCS can be performed and FCS
Even if the base station is switched by, the continuity of the data transmitted to the mobile station can be maintained and the wireless line can be effectively used.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner. It has the function of transmitting the received data information for identifying and the control signal indicating the reception result, and a plurality of base stations are connected via the network side, and it is determined whether or not the mobile station is selected based on the cell selection signal. A buffer management function that outputs a buffer state synchronization signal for synchronizing the data storage state in the buffer with the transmission control unit that receives the control signal and discards the corresponding data from the buffer based on the received data information. Since an FCS is provided, efficient FCS can be performed, and the continuity of the data transmitted to the mobile station can be maintained even if the base station is switched by the FCS. Can be, it can be effectively use of the radio channel.

In the communication system of the present invention, the mobile station transmits request data information indicating the requested data together with the cell selection signal, and the base station selected by the cell selection signal stores in the buffer before the data indicated by the request data information. Since this data is discarded, efficient FCS can be performed, and even if the base station is switched by the FCS, the continuity of the data transmitted to the mobile station can be maintained and the wireless line can be effectively used.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner. Has the function of transmitting the received data information for identifying and the control signal indicating the reception result, and the function of transmitting the request data information indicating the requested data together with the cell selection signal, and a plurality of base stations move based on the cell selection signal. A transmission control unit that determines whether or not a station has been selected, a function that receives a control signal and discards the data that is identified based on the received data information from the buffer, the data that the request data information indicates, and the data that is stored in the buffer before Since a buffer management unit having a function of discarding
Even if you can do CS and switch base stations by FCS,
The continuity of the data transmitted to the mobile station can be maintained, and the wireless line can be effectively used.

In the communication system of the present invention, the mobile station monitors the communication quality with a plurality of base stations and transmits a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner. Has a function of transmitting received data information for identifying and a control signal indicating a reception result, a function of transmitting request data information for identifying requested data together with a cell selection signal, and a plurality of base stations are provided via a network side. A transmission control unit that is connected and determines whether the mobile station is selected based on the cell selection signal, a function that outputs a buffer state synchronization signal for synchronizing the data storage state in the buffer, and a control signal that is received A function to discard the data identified based on the completed data information from the buffer, and a device to discard the data stored in the buffer before the data indicated by the requested data information. Since the buffer management unit having the above is provided, efficient FCS can be performed, the continuity of the data transmitted to the mobile station can be maintained even if the base station is switched by the FCS, and the wireless line is effective. It can be used.

The base station of the present invention is a base station which is connected to the network of the communication system and arranged in a plurality of service areas so as to be capable of wireless communication with the mobile station. The base station receives a cell selection signal from the mobile station. A transmission control unit that determines whether to transmit data to and from the mobile station based on the base station, and a buffer state synchronization signal that synchronizes the data storage state when data is transmitted to the mobile station to another base station. And a buffer management unit for transmitting the data to the base station. Since the buffer management unit discards data from the buffer based on a buffer status synchronization signal from another base station via the network, the data storage statuses of a plurality of base stations are synchronized. be able to.

The base station of the present invention stores in advance the number of data discards for synchronizing the data storage state based on the transmission delay time of the buffer state synchronization signal and the transmission data, and selects the cell selection signal from the mobile station. In this case, data corresponding to the number of discarded data is discarded from the buffer, so that the data storage states of a plurality of base stations can be synchronized.

In the base station according to the present invention, the buffer management unit receives the control signal including the received data information for identifying the received data from the mobile station and discards the corresponding data from the buffer based on the received data information. , The data storage states of a plurality of base stations can be synchronized.

The base station of the present invention is a plurality of base stations arranged in the service area of the communication system so as to be capable of wireless communication with the mobile station, and the base station is connected to the mobile station based on the cell selection signal from the mobile station. Between the transmission control unit that determines whether or not to transmit data between the mobile station and the control signal including the received data information that identifies the received data from the mobile station, and receives the corresponding data from the buffer based on the received data information. Since the buffer management unit for discarding is provided, the data storage states of a plurality of base stations can be synchronized.

In the base station of the present invention, the buffer management unit receives the request data information transmitted from the mobile station and, when selected by the cell selection signal to the mobile station, stores it in the buffer before the data indicated by the request data information. Since the stored data is discarded, the data storage states of a plurality of base stations can be synchronized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a communication system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a base station shown in FIG.

FIG. 3 is a flowchart showing an operation of a transmission control unit installed in the base station according to the first embodiment.

FIG. 4 is a flowchart showing an operation of a transmission control unit and the like mounted on the base station according to the first embodiment.

FIG. 5 is a flowchart showing an operation of a buffer management unit installed in the base station according to the first embodiment.

FIG. 6 is a flowchart showing another operation of the buffer management unit installed in the base station according to the first embodiment.

FIG. 7 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the first embodiment.

FIG. 8 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the second embodiment.

FIG. 9 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the third embodiment.

FIG. 10 is a flowchart showing an operation of a transmission control unit installed in a base station according to the third embodiment.

FIG. 11 is a flowchart showing another operation of the transmission control unit mounted on the base station according to the third embodiment.

FIG. 12 is an explanatory diagram of a communication system according to the fourth embodiment.

FIG. 13 is an explanatory diagram of the base station shown in FIG.

FIG. 14 is a flowchart showing the operation of the buffer management unit shown in FIG.

FIG. 15 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the fourth embodiment.

FIG. 16 is an explanatory diagram of a communication system according to the fifth embodiment.

FIG. 17 is an explanatory diagram of the base station shown in FIG. 16.

FIG. 18 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the fifth embodiment.

FIG. 19 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the sixth embodiment.

FIG. 20 is a flowchart showing an operation of a transmission control unit installed in a base station according to the sixth embodiment.

FIG. 21 is a flowchart showing the operation of the buffer management unit mounted in the base station according to the sixth embodiment.

FIG. 22 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the seventh embodiment.

FIG. 23 is a sequence diagram showing a series of operations regarding FCS between a mobile station and a plurality of base stations according to the eighth embodiment.

FIG. 24 is an explanatory diagram showing a basic configuration of a communication system when realizing a conventional FCS.

FIG. 25 is an explanatory diagram illustrating an operation of a conventional FCS.

[Explanation of symbols]

101 user data distribution device, 102 inter-base station communication device, 103 to 105 base stations A to C, 106 mobile station,
107 communication system, 201 buffer, 202 buffer management section, 203 transmission control section, 01 user data, 02 cell selection signal, 03 buffer state synchronization signal, and 1201 retransmission control information.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K033 AA05 DA02 DA19 DB18                 5K067 AA11 BB04 DD11 DD51 EE02                       EE10 EE24 FF02 HH23 HH28                       JJ32 JJ35 JJ39 JJ52 JJ54                       KK15

Claims (14)

[Claims] 1. A plurality of base stations that receive data from a data distribution device and are formed so that their data storage states can be synchronized with each other, and a base station that communicates under predetermined conditions during wireless communication with the plurality of base stations. And a mobile station capable of selecting the base station, wherein the plurality of base stations synchronize the data storage state of the base station selected by the mobile station with the data storage state of another base station. 2. The mobile station transmits a cell selection signal for monitoring communication quality with a plurality of base stations and switching a base station satisfying a predetermined condition to a communication partner, and the plurality of base stations are connected to the network side. Connected through
A transmission control unit that determines whether the mobile station is selected based on the cell selection signal, and a buffer state synchronization signal that synchronizes the data storage state in the buffer when data is transmitted to the mobile station. The communication system according to claim 1, further comprising a buffer management unit that outputs 3. The mobile station stores the data received before transmitting the cell selection signal, and discards one of the data if the data received after transmitting the cell selection signal matches the stored data. Claim 1 characterized by the above.
Or the communication system according to 2. 4. A plurality of base stations pre-store a data discard number for synchronizing a data storage state based on a transmission delay time of a buffer state synchronization signal and transmission data, and when selected by a cell selection signal from a mobile station. 3. The communication system according to claim 1, wherein the data corresponding to the number of discarded data is discarded from the buffer. 5. The mobile station transmits received data information for identifying received data and a control signal indicating a reception result, and a plurality of base stations receives the control signal and receives corresponding data based on the received data information. Is discarded from the buffer. 6. The mobile station has a function of monitoring a communication quality between a plurality of base stations and transmitting a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner, and a function of receiving received data for identifying received data. It has a function of transmitting a control signal indicating data information and a reception result, and the plurality of base stations are connected via a network side,
A transmission control unit that determines whether the mobile station is selected based on the cell selection signal, and a function that outputs a buffer state synchronization signal for synchronizing the data storage state in the buffer; The communication system according to claim 1, further comprising a buffer management unit having a function of discarding corresponding data from the buffer based on received data information. 7. The mobile station transmits request data information indicating requested data together with a cell selection signal, and the base station selected by the cell selection signal sends the data stored in the buffer before the data indicated by the request data information. The communication system according to claim 1, wherein the communication system is discarded. 8. The mobile station has a function of monitoring communication quality with a plurality of base stations, transmitting a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner, and identifying a received data. It has a function of transmitting a control signal indicating data information and a reception result, a function of transmitting request data information indicating request data together with the cell selection signal, and the plurality of base stations are the mobile stations based on the cell selection signal. , A function of discarding data identified based on the received data information from the buffer upon receiving the control signal, a transmission control unit that determines whether or not the data is indicated in the buffer before the data indicated by the request data information. The communication system according to claim 1, further comprising a buffer management unit having a function of discarding stored data. 9. The mobile station has a function of monitoring a communication quality with a plurality of base stations and transmitting a cell selection signal for switching a base station satisfying a predetermined condition to a communication partner, and a function of receiving received data for identifying received data. A function of transmitting a control signal indicating data information and a reception result, having a function of transmitting request data information for identifying requested data together with the cell selection signal, and the plurality of base stations are connected via a network side,
A transmission control unit that determines whether the mobile station is selected based on the cell selection signal, and a function that outputs a buffer state synchronization signal for synchronizing the data storage state in the buffer; A buffer management unit having a function of discarding the data identified based on the received data information from the buffer, and a function of discarding the data stored in the buffer before the data indicated by the request data information. The communication system according to claim 1. 10. A base station, which is connected to a network of a communication system and arranged in a service area so as to be capable of wirelessly communicating with a mobile station, wherein the mobile station moves based on a cell selection signal from the mobile station. A transmission control unit that determines whether or not to transmit data to and from the station;
A buffer management unit that transmits a buffer status synchronization signal for synchronizing the data storage status to another base station when data is transmitted to the mobile station, and the buffer management unit is provided via the network. The base station discards data from the buffer based on a buffer status synchronization signal from the base station. 11. The data discard number for synchronizing the data storage state based on the transmission delay time of the buffer state synchronization signal and the transmission data is stored in advance, and the data discard is performed when selected by the cell selection signal from the mobile station. 11. A number of pieces of data are discarded from the buffer.
The base station described in. 12. The buffer management unit receives a control signal including received data information for identifying received data from the mobile station, and discards the corresponding data from the buffer based on the received data information. Claim 10
The base station described in. 13. A base station arranged in a service area of a communication system so as to be capable of wireless communication with a mobile station, the base station being configured to communicate with the mobile station based on a cell selection signal from the mobile station. A transmission control unit that determines whether or not to transmit data, and receives a control signal including received data information that identifies received data from the mobile station, and discards corresponding data from the buffer based on the received data information. And a buffer management unit for controlling the base station. 14. The buffer management unit receives the request data information transmitted from the mobile station and, when selected by the mobile station by a cell selection signal, stores the data stored in the buffer before the data indicated by the request data information. The base station according to claim 10, wherein the base station is discarded.