JP2004349783A - Mobile communication method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication method and system capable of easily specifying a retransmission buffer to which frame data are stored, decreasing the number of the retransmission buffers and eliminating the need for search processing for recognizing whether or not data are re-transmission frame data. <P>SOLUTION: The mobile communication system for wirelessly transmitting / receiving data between first and second communication apparatuses 1, 2 is configured by including: a buffer management number provision means 10 for providing a buffer management number used for storing a position in use of the retransmission buffer to an overhead part of frames; and a control means 11 for starting the buffer management number provision means 10 to write the buffer number used for retransmission to a buffer management number storage section and retransmitting frame data when receiving a control signal denoting data reception abnormity from an opposite receiver in the case that either of the communication apparatuses acts like a transmission apparatus. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile communication method and system.
[0002]
[Prior art]
FIG. 6 is a conceptual diagram of a wireless communication system. The first communication device 1 and the second communication device 4 transmit and receive data wirelessly. In the first communication device 1, reference numeral 2 denotes a buffer for holding data, and reference numeral 3 denotes an antenna for transmitting and receiving data wirelessly. In the second communication device 4, reference numeral 5 denotes a buffer for holding data, and reference numeral 6 denotes an antenna for transmitting and receiving data wirelessly.
[0003]
In the system configured as described above, when the first communication device 1 is considered as a transmission device and the second communication device 4 is considered as a reception device, data held in the buffer 2 is read out one by one, 3 is transmitted. On the receiving device 4 side, the transmitted data is received by the antenna 6, the data is extracted, and the data is stored in the buffer 5.
[0004]
In this type of wireless communication, when transmitting a large number of packets, instead of transmitting data in which overhead is added to each packet, a plurality of packets are combined into one frame to form frame data, and the overhead is added to the frame data. There is known a technique of transferring data in frame units by adding a symbol (for example, see Patent Document 1).
[0005]
FIG. 7 is a diagram showing an example of a conventional configuration of frame data. As shown in the figure, the frame data is composed of an overhead part and an actual data part. The overhead section includes a transmission destination ID, a frame (Frame) number, the number of valid packets, and the like. Here, the destination ID is an ID for specifying the destination communication device, the frame number is a serial number assigned to each frame, and the number of valid packets is the number of packets included in the data part.
[0006]
The actual data portion is composed of a predetermined number (N) of packets and N CRCs. There are N packets from # 1 to #N, and the CRC indicates the CRC result for the number of packets. Here, the CRC (Cyclic Redundancy Check) is a mechanism that can automatically detect and correct a data transfer error on the receiving side.
[0007]
For example, in FIG. 6, it is assumed that the first communication device is a wireless base station and the second communication device is a mobile base station. When transmitting and receiving frame data between the wireless base station and the mobile base station, if the receiving device cannot correctly receive the frame data, retransmission control for requesting the transmitting device to retransmit the frame data is performed.
[0008]
In high-speed wireless communication, a period from when the transmitting device transmits frame data to when the transmitting device receives an ACK / NACK response for converting whether the receiving device has correctly received the frame data (a so-called transmission delay). Time), a plurality of frame data are transmitted and received.
[0009]
FIG. 8 is a diagram showing a sequence example of a conventional data communication. Here, a case is shown in which a wireless base station is used as a transmitting device and a mobile base station is used as a receiving device. The transmission delay time is, as shown in the figure, a time from transmission from a radio base station to a mobile base station from a frame (Frame) # 1 until the mobile base station returns to the radio base station. In this example, each frame is transmitted, for example, every 500 μS.
[0010]
Regarding Frame # 1, the mobile base station received NG, so the mobile base station returns a NACK to the radio base station. The radio base station receiving the NACK retransmits Frame # 1. Next, regarding Frame # 2, since the mobile base station has received OK, an ACK is returned to the radio base station. Next, the radio base station that has received the ACK transmits a new Frame (Frame # 14) to the mobile base station.
[0011]
In addition, since the mobile base station has received OK for Frame # 3, an ACK is returned to the wireless base station. However, when a communication failure occurs between the mobile base station and the wireless base station and the ACK cannot be received by the wireless base station, Frame # 3 is retransmitted. Since the mobile base station has received Frame # 3 normally, the retransmitted Frame # 3 is discarded, and ACK is transmitted again to the radio base station. At this time, it is necessary to search for the presence / absence of Frame # 3 from the retransmission buffer in order to determine whether or not it has been received once.
[0012]
[Patent Document 1]
JP-A-2000-59435 (page 2, page 3, FIG. 1)
[0013]
[Problems to be solved by the invention]
In the above-described related art, even if the mobile base station normally receives data, there is a possibility that the same frame data is retransmitted from the wireless base station, and it is necessary to hold a reception buffer for confirmation. Therefore, the reception buffer may not be released until the specified number of retransmissions is reached. That is, a retransmission buffer for “the number of transmission frames within the transmission delay time × the number of retransmissions” is required.
[0014]
For this reason, the radio base station apparatus and the mobile base station require an enormous retransmission buffer for retransmission control. Therefore, when the number of retransmissions increases, a large amount of memory area is required, so that the cost for the memory increases and the physical size also increases.
[0015]
Further, in order to determine whether new frame data has been transmitted or whether the wireless base station has retransmitted due to ACK reception NG, it is necessary to search for a retransmission buffer. The processing performance is degraded.
[0016]
The present invention has been made in view of such a problem, and a retransmission buffer to be stored can be easily specified, the retransmission buffer can be reduced, and a search process for recognizing whether the data is retransmission frame data is unnecessary. It is an object to provide a mobile communication method and system.
[0017]
[Means for Solving the Problems]
In the present invention, a buffer management number is added to the overhead information of the frame data transmitted and received between the wireless base station and the mobile base station. The buffer management number is a number indicating a reception buffer that stores transmission frame data, and can take a value corresponding to the number of frames transmitted within a transmission delay time. When 13 frames are transmitted during the transmission delay time as shown in FIG. 8, the values are "1 to 13". Thereby, the retransmission buffer to be stored can be easily specified, the number of retransmission buffers can be reduced, and a search process for recognizing whether the data is retransmission frame data becomes unnecessary.
(1) The invention described in claim 1 is as follows. FIG. 1 is a flowchart showing the principle of the method of the present invention. The present invention relates to a mobile communication method in which a first communication device and a second communication device wirelessly transmit and receive data, and a buffer management number for storing a use position of a retransmission buffer in an overhead portion of a frame. A storage unit is provided (Step 1). When one of the communication devices functions as a transmission device, a buffer number to be retransmitted to the buffer management number storage unit when a control signal indicating an abnormal data reception is received from a partner reception device. Is written and retransmitted (step 2).
[0018]
With this configuration, the receiving device can determine whether the frame transmitted from the transmitting device is a frame that has already been received, so that a search process for recognizing whether the frame is retransmitted frame data is unnecessary.
(2) The invention described in claim 2 is as follows. FIG. 2 is a block diagram showing the principle of the present invention. The same components as those in FIG. 6 are denoted by the same reference numerals. The system shown in the figure constitutes a mobile communication system in which a first communication device and a second communication device transmit and receive data wirelessly. In the figure, reference numeral 1 denotes a first communication device, and 4 denotes a second communication device, which perform wireless communication via antennas 3 and 6, respectively.
[0019]
In the first communication device 1, reference numeral 10 denotes a buffer management number assigning unit that assigns a buffer management number for storing a use position of a retransmission buffer to an overhead portion of a frame, and reference numeral 11 denotes one of the communication devices functioning as a transmission device. In this case, when a control signal indicating an abnormal data reception is received from the receiving apparatus, the buffer management number assigning means 10 is activated to write the frame number of the frame to be retransmitted in the buffer management number storage portion and to retransmit the data.
[0020]
With this configuration, the control unit 11 activates the buffer management number assigning unit 10 to write the buffer number of the frame to be retransmitted in the buffer management number storage part and retransmit the frame. It is possible to promptly recognize whether or not the transmitted frame data is already correctly received frame data. Therefore, a retransmission buffer to be stored can be easily specified, the retransmission buffer can be reduced, and a mobile communication method and system that does not require a search process for recognizing retransmission frame data can be provided.
(3) The invention according to claim 3 is characterized in that the first communication device is a radio base station and the second communication device is a mobile base station.
[0021]
With this configuration, data can be transferred between the wireless base station and the mobile base station.
(4) The invention according to claim 4, wherein the mobile base station receives the frame data retransmitted from the radio base station, reads the buffer number from the buffer management number storage portion of the frame data, and reads the buffer number. When recognizing that it is the same as the buffer number of the already transmitted frame data, the frame data is discarded.
[0022]
With this configuration, if the frame data that has already been transferred and the retransmission data are the same, the normal state can be maintained by discarding the retransmission frame data.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
FIG. 3 is a block diagram showing an embodiment of the present invention. The same components as those in FIG. 2 are denoted by the same reference numerals. This embodiment shows a case where a wireless base station is used as the first communication device 1 and a mobile base station is used as the second communication device 4. If the communication device is determined in this way, data can be transferred between the wireless base station and the mobile base station.
[0025]
In the wireless base station 1, reference numeral 20 denotes a frame forming unit for assembling packet data into frames, 21 denotes a buffer for receiving and holding the output of the frame forming unit 20, and 22 transmits the output of the buffer 21 sequentially from the antenna 3 by radio. It is a communication unit.
[0026]
Reference numeral 10 denotes a buffer management number assigning unit serving as a buffer management number assigning unit that assigns a buffer management number for storing the use position of the retransmission buffer to the overhead portion of the frame. 11 receives the control signal of the data reception abnormality from the mobile base station 4, activates the buffer management number assigning means 10, writes the frame number of the frame to be retransmitted in the buffer management number storage part of the frame, and retransmits the frame. It is a control unit as control means for controlling the entire operation.
[0027]
In the mobile base station 4, a communication unit 30 receives data from the antenna 6, a buffer 32 holds data from the communication unit 30, and a frame processing unit 33 decomposes frame data from the buffer 32 into packets. It is. Reference numeral 31 denotes a control unit which, when data is not normally received, requests the wireless base station 1 to retransmit frame data and also controls the entire operation. The operation of the system configured as described above will be described below.
[0028]
FIG. 4 is a diagram showing a configuration example of frame data according to the present invention. As shown in the figure, the frame data is composed of an overhead part and an actual data part, which is the same as the conventional frame format shown in FIG. The difference is that a buffer management number in which the frame number of the frame to be retransmitted is written in the overhead section is provided. Other configurations of the transmission destination ID, the frame number, the number of valid packets, and the actual data portion are the same as those of the conventional example.
[0029]
That is, the destination ID is an ID for specifying the destination mobile base station, the Frame (frame) number is a serial number assigned to each frame, and the number of valid packets is the number of packets included in the data part. , Packet #i (i = 1 to N) is packet data, and CRC is a CRC result for the number of packets.
[0030]
FIG. 5 is a diagram showing an example of a data communication sequence according to the present invention. 4 shows a sequence on the wireless base station side and the mobile base station side. The input packet enters the frame forming unit 20 and is framed. The framed data is stored in the buffer 21. The communication unit 22 reads the data stored in the buffer 21 and wirelessly transmits the data to the mobile base station 4 via the antenna 3 (S1).
[0031]
On the mobile base station 4 side, the communication unit 30 receives the frame data via the antenna 6. The frame data received by the communication unit 30 is stored in the subsequent buffer 32. The frame data stored in the buffer 32 is read out one by one and enters the frame processing unit 33. The frame processing unit 33 returns the read frame data to packet data and outputs the packet data.
[0032]
In such a series of data transfer operations, when the control unit 31 receives frame data normally, it stores the data in the designated buffer 32a and returns ACK (S2). Here, the received buffer number is stored in the buffer 32a. The ACK data is transferred from the mobile base station to the wireless base station (S3).
[0033]
Here, in step S3, if the reception of the ACK data has failed on the radio base station side, there is a possibility that the reception on the mobile base station side has failed, so the control unit 11 on the radio base station side retransmits the frame data. Is performed (S4). At this time, since the control unit 11 recognizes that the frame data is to be retransmitted, the control unit 11 activates the buffer management number assigning unit 10 and stores the buffer management number storage unit in the overhead unit of the frame data stored in the buffer 21. Then, the number of the buffer to be retransmitted is written into the file and retransmitted (S5).
[0034]
With this configuration, the control unit 11 activates the buffer management number assigning unit 10 to write the frame number of the frame to be retransmitted in the buffer management number storage unit and retransmit the frame. It is possible to promptly recognize whether or not the transmitted frame data is already normally received frame data. Therefore, a retransmission buffer to be stored can be easily specified, the retransmission buffer can be reduced, and a mobile communication method and system that does not require a search process for recognizing retransmission frame data can be provided.
[0035]
Here, on the mobile base station side, the frame data is received by the communication unit 30 and stored in the buffer 32. The control unit 31 reads the buffer number stored in the buffer management number storage unit from the frame data stored in the buffer 32. Here, if the buffer number matches the buffer number already stored in the buffer 32a, the frame data has already been received, and the control unit 31 discards the received frame data (S6). .
[0036]
As described above, according to the present invention, if the data already transferred and the retransmission data are the same, the normal state can be maintained by discarding the retransmission frame data.
[0037]
In the above-described embodiment, a case where a wireless base station is used as the first communication device and a mobile base station is used as the second communication device is taken as an example. However, the present invention is not limited to this, and the present invention can be similarly applied to any system that transmits and receives data between the first communication device and the second communication device.
[0038]
【The invention's effect】
According to the present invention, the following effects can be obtained.
(1) According to the first aspect of the present invention, the receiving device can determine whether the frame transmitted from the transmitting device is already received, so that the search for recognizing whether the frame is retransmitted frame data is performed. No processing is required.
(2) According to the second aspect of the present invention, the control means activates the buffer management number assigning means to write the frame number of the frame to be retransmitted in the buffer management number storage portion and retransmit the frame. The device can promptly recognize whether or not the transmitted frame data is already correctly received frame data. Therefore, a retransmission buffer to be stored can be easily specified, the retransmission buffer can be reduced, and a mobile communication method and system that does not require a search process for recognizing retransmission frame data can be provided.
(3) According to the third aspect of the invention, data can be transferred between the radio base station and the mobile base station.
(4) According to the fourth aspect of the present invention, if the frame data already transferred and the retransmission data are the same, the normal state can be maintained by discarding the retransmission frame data. .
[0039]
As described above, according to the present invention, a retransmission buffer to be stored can be easily specified, the number of retransmission buffers can be reduced, and a mobile communication method and system that does not require a search process for recognizing retransmission frame data are required. Can be provided.
[Brief description of the drawings]
FIG. 1 is a flowchart showing the principle of the method of the present invention.
FIG. 2 is a principle block diagram of the present invention.
FIG. 3 is a block diagram showing an embodiment of the present invention.
FIG. 4 is a diagram illustrating a configuration example of frame data according to the present invention.
FIG. 5 is a diagram showing an example of a data communication sequence according to the present invention.
FIG. 6 is a conceptual diagram of a wireless communication system.
FIG. 7 is a diagram showing a conventional configuration example of frame data.
FIG. 8 is a diagram showing a sequence example of a conventional data communication.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 communication device 2 buffer 3 antenna 4 communication device 5 buffer 6 antenna 10 buffer management number assigning means 11 control means

Claims (4)

In a mobile communication method in which a first communication device and a second communication device transmit and receive data wirelessly, a buffer management number storage unit for storing a use position of a retransmission buffer is provided in an overhead portion of a frame (step 1). ),
In the case where one of the communication devices functions as a transmitting device, if a control signal indicating an abnormal data reception is received from the other receiving device, the number of the buffer to be retransmitted is written to the buffer management number storage section and retransmitted (step 2).
A mobile communication method characterized by doing so. In a mobile communication system in which a first communication device and a second communication device transmit and receive data wirelessly, a buffer management number for assigning a buffer management number for storing a use position of a retransmission buffer to an overhead portion of a frame Providing means;
When any one of the communication devices functions as a transmission device, when receiving a control signal of a data reception abnormality from the other reception device, the buffer management number assigning means is activated to retransmit the buffer number to the buffer management number storage unit. Control means for writing and retransmitting
A mobile communication system configured by providing a mobile communication system. 3. The mobile communication system according to claim 2, wherein the first communication device is a wireless base station, and the second communication device is a mobile base station. The mobile base station receives the frame data retransmitted from the wireless base station, reads the buffer number from the buffer management number storage portion of the frame data, and sets the buffer number to the buffer number of the already transmitted frame data. 4. The mobile communication system according to claim 3, wherein when recognizing that they are the same, the frame data is discarded.

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