JP2934279B2 - Mobile communication packet transfer control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a case where a plurality of packet transfer routes exist between two stations, and when this route is changed at a certain point, packet loss or double transmission is performed. In particular, the present invention relates to a mobile communication packet control method that requires different retransmission control procedures between a wireless section and a wired section of a relay route.

[Conventional technology]

FIG. 5 is a block diagram showing a conventional example. In FIG. 5, 1 is an exchange, 2a, 2b and 2c are base stations, 3 is a mobile station, and 4 is a relay network. In this conventional example, the switching center 1 transmits and receives packets to and from the base station 2a, 2b or 2c via some switching centers as the relay network 4. The error retransmission control is performed between the base station 2a, 2b and 2c and the exchange 1. In addition, the exchange 1 transmits and receives packets to and from the mobile device 3 using a unique error retransmission control procedure because transmission characteristics such as an error rate are different between the wireless section and the wired section.

FIG. 6 shows an example of a packet transmission / reception sequence between the exchange 1 and the mobile station 3 in FIG. The exchange 1, the base station 2a, and the mobile station 3 have a retransmission memory for storing transmitted packets until a reception response signal is received in order to perform retransmission control. Note that the mobile device 3 is not shown because it does not directly relate to the following description. FIG.
FIG. 4 is an explanatory diagram showing a transmission / reception sequence and a state of a retransmission memory. The packet (1) and the puncture (A) have the same data, but have different sequence numbers (1) and (A) according to the error retransmission control procedure in each section.

Hereinafter, a conventional mobile communication packet transfer control method will be described with reference to FIGS. 5 and 6. FIG. For example, as shown in FIG. 6, when transmitting a packet from the exchange 1 to the mobile station 3, the base station 2a uses an error retransmission control procedure defined between the exchange 1 and the base station 2a. Packet (1) 61 transmitted from exchange 1 is received, and packet (1) 61 is received.
Is transmitted to the exchange 1. When the exchange 1 receives the reception response signal 62, the exchange 1
It is no longer necessary to retransmit the packet (1) to the base station 2a, and the packet (1) 61 stored in the retransmission memory 7 is deleted. Base station 2a
Then, when the packet (A) 63 is transmitted to the mobile station 3 and the reception response signal 64 corresponding to the packet (A) 63 is received, the packet (A) 63 stored in the retransmission memory 6a is deleted, and The transmission of the packet with the mobile device 3 is completed.

When a reception response signal is not returned from the receiving side within a specified time after transmitting a packet between the exchange 1 and the base station 2a and between the base station 2a and the mobile station 3, retransmission is performed. The same packet is retransmitted by using the memory for communication.
The packet transfer from the mobile station 3 to the exchange 1 is performed in the same manner.

[Problems to be solved by the invention]

By the way, in the mobile communication field, when a mobile station moves during communication, when a wireless zone changes, a switching station and a mobile station are used as in a channel switching process such as switching of a wireless channel used for communication. There are a plurality of packet transfer routes between the routers and this route may be changed at some point.

FIG. 7 and FIG. 8 show examples of channel switching sequences during communication, which are taken in order to prevent loss of packets being transmitted and received or double transmission to a destination in the conventional example of FIG. Show. 7 and 8, the packet transfer from the exchange 1 to the mobile station 3 is shown, but the packet transfer from the mobile station 3 to the exchange 1 is performed in the same procedure. 7 and 8, the sequence numbers are different between the wireless section and the wired section. In the following, Fig. 5,
Referring to FIGS. 7 and 8, radio channel switching is performed while packets are being transmitted and received between the exchange 1 and the mobile station 3 via the base station 2a, and the packet passes through the base station 2b. The case where the state is changed will be described.

As shown in FIG. 7, when channel switching occurs,
The base station 2a transmits a transmission interruption signal 71 for instructing the exchange 1 not to transmit a packet. Base station 2a
Then, all the unacknowledged packets (B) 72 accumulated in the queue of the base station 2a are transmitted to the mobile device 3, the reception response signals 73 for all the packets are received by the base station 2a, and the unacknowledged punk packets are received by the base station 2a. , Loss of packets and double transmission can be prevented. After switching the channel, the sequence number is reset, and a transmission restart signal 74 is transmitted from the base station 2b to the exchange 1, so that the exchange 1 transmits and receives packets to and from the mobile device 3 via the base station 2b. Resume. However, this method has a problem that it takes time from the occurrence of channel switching to the completion of channel switching.

Also, as shown in the eighth signal, when the channel switching occurs, the base station 2a transmits a packet transmission interruption signal 81 to the exchange 1, and the base station 2a transmits an unconfirmed packet (B ) 82 and transfer the sequence number, and after receiving the transfer completion signal 83 from the base station 2b, empty the retransmission memory 6a. Even after the channel switching, the base station 2b takes over the unconfirmed packet and the sequence number, thereby preventing packet loss and double transmission. After the switching, the unconfirmed packet (B) is transmitted to the mobile device 3. However, in this method, since all unconfirmed packets are transferred from the source base station 2a to the destination base station 2b, there is a problem that the amount of transfer information becomes enormous.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, so that when there are a plurality of packet transfer routes between a switching center and a mobile station and this route is changed at a certain point in time, the change time of this route is changed. It is an object of the present invention to provide a mobile communication packet transfer control method capable of shortening the communication time and reducing the amount of transfer information between base stations.

[Means for solving the problem]

The present invention includes a plurality of mobile stations, a plurality of base stations, and an exchange, wherein the mobile station, the base station, and the exchange are located between the mobile station and the exchange. Including means for transmitting and receiving packets via the base station deployed in the wireless zone where there is, and retransmission control means,
The base station includes a retransmission memory that stores a packet received for a predetermined time until a reception response signal is received for retransmission confirmation of the packet, and the base station operates between the exchange and the mobile station. When transmitting and receiving packets, a mobile communication packet including means for assigning a number to a packet to be transmitted and received by a base station and independently establishing a communication path with the exchange or the mobile station to transmit and receive the packet. In the transfer control method, the base station, when receiving a packet from the mobile station or the switching station as a packet transmitting station, transmits the packet to the switching station or the mobile station as a packet receiving station and After storing in a retransmission memory and receiving a reception response signal for the packet from the packet receiving station, Characterized in that it comprises a means for erasing the packet and sends an acknowledgment signal the retransmission memory for the packet.

[Action]

When transmitting and receiving packets between an exchange and a mobile station via a base station, the base station establishes a link for packet transmission and reception with the exchange and the mobile station individually and transmits and receives packets. In addition, the sequence numbers of the packets are independently assigned and managed. When the base station receives a packet from the switching center or mobile station,
Each packet is transmitted to the mobile station or the exchange and stored for a predetermined time until the reception confirmation signal is received in the retransmission memory. After the reception confirmation signal is received for the packet, the reception confirmation signal for packet reception is exchanged. Return to station or mobile. Further, the base station confirms the sequence number of the packet received by the partner station when the channel switching has occurred, and notifies the base station or the switching station of the channel switching destination.

Therefore, the mobile unit and the exchange maintain the packet in the retransmission memory until the packet reception is completed, thereby preventing loss or double transmission of the packet, and performing switching processing for the unconfirmed packet. Since it becomes unnecessary, it is possible to shorten the route change time and reduce the amount of transfer information between base stations. Further, it is possible to reduce the amount of information transferred between base stations and between base station exchanges during channel switching processing.

〔Example〕

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

FIG. 1 is a block diagram showing a main part of an embodiment of the present invention.

In the present embodiment, a plurality of mobile stations 3 and a plurality of base stations 2a and 2b
And 2c, and an exchange 1, and the mobile station, the base stations 2a and 2b
And 2c and the exchange 1 are means for transmitting and receiving packets between the mobile station 3 and the exchange 1 via the base station 2a, 2b or 2c located in the radio zone where the mobile station 3 is located. In a mobile communication packet transfer control system including a retransmission memory as retransmission control means, the base stations 2a, 2b, and 2c, which are features of the present invention, respectively include a mobile station 3 as a packet transmission station or a switching station. When a packet is received from the packet transmitting station, the packet transmitting station transmits the packet to the exchange 1 or the mobile station 3 as a packet receiving station, and receives a reception response signal for the packet from the packet receiving station. On the other hand, it includes a packet transfer confirmation means 5 for controlling transmission of a reception response signal for the packet.

 Next, the operation of the present embodiment will be described.

FIG. 2 is an explanatory diagram showing an example of a packet transmission / reception sequence according to the present embodiment. When transmitting a packet from the exchange 1 to the mobile station 3, when the base station 2a receives the packet (1) 21 transmitted to the exchange 1, the base station 2a transmits the packet (1) to the transmission source unlike the conventional method. ) Receive response signal for 21
The packet (A) 23 is transmitted to the mobile station 3 without transmitting the packet 22.

When the base station 2a receives the reception response signal 24 for the packet (A) 23 from the mobile station 3, the base station 2a deletes the packet (A) 23 stored in the retransmission memory 6a and sends the base station 2a to the exchange 1.
Transmits a reception response signal 22 to the received packet (1) 21.

When the exchange 1 receives the reception response signal 22, it deletes the packet (1) 21 stored in the retransmission memory 7, and the packet transfer procedure between the exchange 1 and the mobile station 3 is completed.

If, after transmitting a packet between the exchange 1 and the base station 2a and between the base station 2a and the mobile station 3, a reception response signal is not returned from the receiving side within the specified time, retransmission is performed. The same packet is retransmitted by using the memory for communication.
The packet transfer from the mobile station 3 to the exchange 1 is performed in the same manner.

3 and 4 are explanatory diagrams showing an example of a channel switching sequence during communication in the present embodiment.
The figure shows a case where the sequence number is reset in the channel switching implementation (corresponding to FIG. 7 of the conventional example), and FIG. 4 shows a case where the sequence number is taken over in the channel switching implementation (corresponding to FIG. 8 of the conventional example). . 3 and 4, the packet transfer from the exchange 1 to the mobile station 3 is shown, but the same procedure is performed for the packet transfer from the mobile station 3 to the exchange 1.

Hereinafter, a case will be described in which the wireless channel switching is performed while packets are being transmitted and received between the exchange 1 and the mobile device 3 via the base station 2a, and the state is changed to a state via the base station 2b. .

In FIG. 3, first, the exchange 1 receives a packet (1).
Is transmitted to the base station 2a and stored in the retransmission memory 7. When the base station 2a receives this, the packet (A)
To the mobile station 3 and its retransmission memory
Hold at 6a. Next, the exchange 1 transmits the packet (2) to the base station 2a and stores it in the retransmission memory 7.
That is, in this state, packet (1) and packet (2) are held in retransmission memory 7 of exchange 1. When the base station 2a receives the packet (2), the packet (B)
Is held together with the packet (A) in the retransmission memory 6a.

At this point, when channel switching occurs, the base station 2a
Transmission interruption signal to exchange 1 when channel switching occurs
The mobile station 3 transmits a reception confirmation sequence number notification request signal 32 to the mobile device 3. Upon receiving the reception confirmation sequence number notification request signal 32, the mobile station 3 transmits to the base station 2a a reception confirmation sequence number notification signal 33 to which the sequence number (A) of the packet received by the mobile station 3 is added. Mobile device 3
The base station 2a which has received the reception confirmation sequence number notification signal 33 from the base station 2 erases the packet (A) in the retransmission memory 6a and the packet received by the mobile device 3 indicated by the reception confirmation sequence number notification signal 33 ( To the exchange 1, a reception confirmation sequence number notification signal 34 to which the sequence number (1) of the packet between the exchanges corresponding to the sequence number of A) is added. When the exchange 1 receives the acknowledgment sequence number notification signal 34, it deletes the packet (1) in the retransmission memory 7.

As a result, the exchange 1 can surely know the packet received by the mobile station 3, so that loss of the packet and double transmission can be prevented.

In the channel switching, the sequence number is reset by re-adding the sequence number of the packet (2) to the packet (1).

After the switching, the base station 2b transmits a transmission restart signal 35 to the exchange 1. When the exchange 1 receives the transmission restart signal 35, the exchange 1 transmits a stagnant packet that has not been acknowledged by the exchange 1 to the mobile device 3 via the base station 2b.

That is, the exchange 1 transmits the newly reset packet (1) and the packet (2) to the base station 2b in order, and when the base station 2b receives them, the mobile station sequentially transmits the packet (A) and the packet (B). 3 and receives a reception response signal sequentially transmitted from the mobile station 3 for each packet, thereby erasing each packet from the retransmission memory 6b, and transmitting the received packet to the exchange 1. Send a response signal. The exchange 1 deletes the packet in the retransmission memory 7 by receiving these reception response signals.

In FIG. 4, when channel switching occurs in the base station 2a, a transmission interruption signal 41 is transmitted to the exchange 1. Further, the base station 2a transfers the sequence number (A) whose reception has already been confirmed by the mobile station 3 to the base station 2b by the confirmed sequence number notification signal 42. At this time, the sequence number is not reset after the channel switching. By taking over the sequence number, loss of the packet and double transmission can be prevented. After switching, the exchange 1 sends unconfirmed packets to the base station.
The data is transmitted to the mobile device 3 via 2b.

As described above, in the channel switching during communication, the packet receiving station is notified of the packet received by the packet receiving station, as compared with the conventional method. Alternatively, by simply transferring the sequence number from the base station before switching to the base station after switching, packet loss and double transmission can be prevented, so that the time from the channel switching instruction to the completion of channel switching is reduced, The amount of transfer information between base stations can be reduced.

As is clear from the above, according to the present embodiment, the packet is transmitted and received between the exchange and the mobile station, and the packet is stored in the retransmission memory of the transmission source until the transmission of the packet is completed. In addition, even when the packet transfer route is changed, it is possible to efficiently execute a control that does not cause loss of a packet being transmitted or received or double transmission to a destination.

Further, the present invention is applicable to a general packet communication system involving a packet transfer route change.

〔The invention's effect〕

As described above, according to the present invention, the packet transfer route is changed by the exchange and the mobile station by holding the packet until the reception of the packet to the mobile station or the exchange is completed. There is an effect that the control in the case can be executed efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of one embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of the packet transmission / reception sequence. FIG. 3 is an explanatory diagram showing an example of the channel switching sequence. FIG. 4 is an explanatory diagram showing another example of the channel switching sequence. FIG. 5 is a block diagram showing a main part of a conventional example. FIG. 6 is an explanatory diagram showing an example of the packet transmission / reception sequence. FIG. 7 is an explanatory diagram showing an example of the channel switching sequence. FIG. 8 is an explanatory diagram showing another example of the channel switching sequence. 1 ... Exchange station, 2a, 2b, 2c ... Base station, 3 ... Mobile device,
4 ... Relay network, 5 ... Packet transfer confirmation means, 6a, 6b,
7 ... Retransmission memory, 21, 61 ... Packet (1), 22,
24, 62, 64, 73 ... Reception response signal, 23, 63 ... Packet (A), 31, 41, 71, 81 ... Transmission suspension signal, 32 ... Reception confirmation sequence number notification request signal, 33, 34 …… Reception confirmation sequence number notification signal, 35, 74 …… Transmission restart signal, 42
... A confirmed sequence number notification signal, 72, 82... Packet (B), 83.

Continuation of the front page (72) Inventor Fumio Iwamoto 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-63-202141 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) H04B 7/24-7/26 H04L 11/00 H04Q 7/00-7/38

Claims (3)

(57) [Claims] 1. A mobile station comprising: a plurality of mobile stations; a plurality of base stations; and a switching center, wherein the mobile station, the base station, and the switching station perform the mobile operation between the mobile station and the switching station. And means for transmitting and receiving packets via the base station provided in the wireless zone where the device is located, and retransmission control means, wherein the base station receives a reception response signal for packet retransmission confirmation A retransmission memory for storing packets received for a predetermined time until the base station assigns numbers to packets transmitted and received by the base station when transmitting and receiving packets between the exchange and the mobile station. And a means for independently establishing a communication path with the exchange or the mobile station to transmit and receive a packet. In the mobile communication packet transfer control system, the base station comprises: Or, when a packet is received from the exchange, the packet is transmitted to the exchange or the mobile station as a packet reception station and stored in the retransmission memory, and a reception response to the packet from the packet reception station is received. A mobile communication packet transfer control method, comprising: after receiving a signal, transmitting a reception response signal to the packet transmitting station to the packet transmitting station and erasing the packet in the retransmission memory. 2. The base station, when channel switching occurs between the mobile station and the mobile station, requests the mobile station to perform a reception number confirmation request for confirming the number of a packet received by the mobile station so far. The exchange includes means for notifying the exchange that the response has been made to the exchange, and the exchange which transmits a packet by adding a new packet number after the channel switching to the next packet that has been notified. The mobile communication packet transfer control method according to claim 1. 3. The mobile station as a packet receiving station, comprising: a reception number for confirming the number of a packet received by the mobile device up to that time when a channel switch occurs between the base station and the mobile device; A means for making a request for confirmation and notifying the responded number to the base station of the channel switching destination of the mobile station. The base station of the channel switching destination takes over the notified number and establishes a connection with the mobile station. 2. The mobile communication packet transfer control system according to claim 1, further comprising means for continuing packet transmission and reception.