JPH08223217A - Radio packet multiplexing method - Google Patents

Abstract

PURPOSE: To improve the transmission efficiency without increasing an overhead on a radio packet and to receive a succeeding packet even when the reception is interrupted. CONSTITUTION: A radio control station or a terminal station going to send a message collects in advance plural packets to generate packet groups 2-1-2-2 and provides a multiplex identifier 2-3 TEI to only a head packet set at first in the packet groups and provides a sequence number 2-4 SN representing a packet group to which a concerned packet belongs to each packet. Packets being components of the packet groups are sent continuously on a communication channel, a receiver side receives the head packet based on the multiplex identifier and receives packets having the same sequence number as that of the head packet as packets belonging to the same packet group as the head packet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for multiplexing wireless packets in a wireless communication system.

[0002]

[Prior art]

(Prior Art 1: LAPD) Packets of a plurality of terminals are multiplexed on the ISDN D channel. Each terminal and packet switch receives all packets (LAPD frames), and the header of each LAPD frame has a terminal identifier (TEI) assigned to each terminal.
Is assigned to each terminal and packet switch.
The EI is collated to identify the packet.

FIG. 10 shows how packets are multiplexed on the D channel. Terminal A (10-2), B (10-
3) and C (10-4) are bus-connected to the D channel (10-1), and downlink packets (10-
6 to 10-9) are all received. After reception, the TEI (10-5) assigned to the header of each packet is compared with the TEI assigned to the own terminal, and if they match, the terminal recognizes that the packet is addressed to itself and performs processing. However, if they do not match, the packet is discarded. In the case of an upstream packet, each terminal sends a packet containing its own TEI,
The exchange (10-10) refers to this TEI to identify the packet.

(Prior Art 2: Reservation Hold Random Access Control Method (Japanese Patent Application No. 6-209366)) In the conventional skyline control access method, when an uplink radio line from a mobile station to a base station is not used. An access from a mobile station under its control is permitted by notifying a skyline signal, and a prohibition signal is notified at the time when an uplink radio line is used to prohibit access from other mobile stations. However, due to factors such as fading and shadowing on the wireless line, even if the mobile station continuously transmits signals, the base station may not be able to partially receive the signals. In this case, in the skyline control access method, the prohibition signal changes to a skyline signal even though the packet transmission is not completed, so that the access operation is performed again, which causes an increase in packet delay and a decrease in throughput.

In order to solve this problem with the reservation reservation type random access control method, even if the signal from the mobile station cannot be received, the radio signal is restored within the fixed time by notifying the prohibited signal for the fixed time. In this case, the access control method enables the mobile station to continuously transmit packets.

FIG. 11 shows an operation example of the reservation reservation type random access control method. Here, the channel is composed of a downlink control channel (11-1) from the base station to the mobile station and an uplink channel (11-2) from the mobile station to the base station, and each has 3 channels.
Channel time division multiplexing. The first channel out of the three channels is used as the packet channel. The access control signal in the downlink control channel includes a skyline signal (11-4) and a prohibition / ACK signal (11-
3), there is a prohibit / NAK signal (11-5). Mobile station A
While the packet 11-6 is transmitted from the base station, the base station notifies the prohibit / ACK signal (11-3), but when the packet transmission is completed, the mobile station sets the transmission end flag in the final packet. When the base station detects this, the prohibition signal is immediately changed to a sky line signal. On the other hand, it is assumed that while the packet 11-7 is transmitted from the mobile station B, the slots 11-8 and 11-9 are not received by the base station due to an error in the wireless section. At this time, since the base station cannot detect the transmission end flag, the channel is held by broadcasting the prohibition / NAK signal (11-5) for a certain period of time, and at the same time, the mobile station which is transmitting is prohibited / NA.
By receiving the K signal, the remaining packet or the retransmitted packet is continuously transmitted in the corresponding slot.

[0007]

[Problems to be Solved by the Invention]

(1) When packet multiplexing is performed in the wireless section, the frequency of retransmission due to a transmission error increases because the transmission quality of the line is poorer than that of wired communication. Therefore, it is generally necessary to shorten the packet length of wireless packets as compared with wired packets.

On the other hand, in order to perform packet multiplexing on a common channel, it is necessary to give an identifier such as TEI in LAPD to each packet. Therefore, if the packet length is shortened, the overhead due to the identifier increases. . This is one of the factors that significantly reduce the efficiency of wireless packets as compared to wired packets.

(2) Further, due to the influence of fading on the wireless line, even if wireless packets are continuously transmitted by the above method, the packet group may not be partially received on the receiving side. It is also assumed that the continuous transmission of the packet group is temporarily interrupted due to the occurrence of interrupt processing on the transmitting side. In this case, another packet group may occur while the reception is interrupted. Therefore, in this method in which the identifier is included only in the first packet, the relation with the subsequent packet group received after the interruption is the receiver side. Then, there is a problem that it becomes unclear and the packet cannot be identified. Also in the reservation hold type random access control method, if the interruption period is long, it is possible to determine whether it is the signal to the own station or the signal to another station generated during the interruption even when the prohibit / NAK signal is received after the wireless line is restored. There is a risk of disappearing.

It is an object of the present invention to provide a wireless packet multiplexing method capable of improving transmission efficiency without increasing the overhead of a wireless packet, and receiving a subsequent packet even if the reception is interrupted. .

[0011]

For the above-mentioned reason, wireless packet communication is generally performed by dividing a wire packet or an upper layer message into a plurality of shorter packets. Therefore, the packets divided in these wireless sections generally occur continuously in wired packets or message units. Therefore, the present invention focuses on the continuity of the wireless packet generation process, proposes a method of grouping a series of wireless packets into a packet group, assigning an identifier only to the first packet, and continuously transmitting the remaining packet groups. are doing. Here, “continuously” also includes the case where one channel of the time division multiplexing channel is continuously used. On the receiving side, a group of continuously received packets is collected and the packet group is identified based on the identifier of the first packet.

Further, in order to solve the problem (2), in the present invention, a sequence number is assigned to the packet group, and the sequence number for the packet group after the reception is resumed even if the reception is temporarily interrupted due to the above reasons. If it matches the sequence number before interruption, it is assumed that they are the same packet group, and we propose a method to identify the packet group after interruption by the identifier shown in the first packet of the packet group before interruption. There is. As a specific method of assigning a sequence number to a packet group, a method of directly assigning each packet (see Embodiment 1) or a method in which a base station or the like broadcasts an access control signal including a sequence number A method is conceivable in which the mobile station transmits the packet group to which the sequence number is assigned while being notified (see the second embodiment). However, in the former case, in order to obtain the effect of the present invention, the number of bits expressing the sequence number is smaller than the number of bits expressing the identifier.

[0013]

In the wireless packet multiplexing method according to the present invention, a series of wireless packets are grouped as a packet group, an identifier is given only to the first packet, and the remaining packet groups are continuously transmitted. Since it is not necessary to give an identifier to the packet, it is possible to mitigate the increase in overhead due to the shortened packet length. In addition, a sequence number is assigned to each packet, and subsequent packets are identified by the sequence number from the correspondence between the identifier shown in the first packet and the sequence number, so that the packet group can be received due to fading in the wireless section. Even in the case of temporary interruption, it is possible to identify the subsequent packet group by collating the sequence numbers.

[0014]

【Example】

(Embodiment 1) This embodiment 1 describes a method of directly assigning a sequence number to each packet when a downlink packet is transferred from a base station to a mobile station. FIG. 1 shows a state of packet transfer when the packet multiplexing method according to the first embodiment is used, and FIG. 2 shows a configuration of a packet group according to the first embodiment. Here, the channel uses the first slot of the time division multiplexing of three channels as the packet channel, as in FIG. Packet group (1-3, 1-
5) is the first packet (1-2, 1-) as shown in FIG.
4, 2-1) and the subsequent packet (2-2), the identifier TEI (2-3) and the sequence number SN (2-4) for the first packet, and the sequence number (2-4) for the subsequent packet. Only each of them is given together with the transfer data (2-5).

First, the base station transmits the packet group (1-3) to the mobile station A in order to transmit the first packet (1-
2) is transmitted. Each mobile station receives this head packet, and if the identifier (2-3) addressed to itself is given, stores the sequence number and receives the subsequent packet (1-6). If it is not addressed to the station, the packet is discarded (1-7). Next, the base station transmits the packet group (1-5) to the mobile station B in the same procedure, but it is assumed that the slot 1-10 is not received by the mobile station B due to an error in the wireless section. At this time, the mobile station B looks at the sequence number of the subsequent packet received after the wireless line is restored,
If the sequence numbers set in the first packet (1-4) match before the interruption, it is determined that they are the same packet group and the reception of the packet group is restarted.

FIG. 3 shows a control flow of the base station in the first embodiment. When a transmission packet group to the mobile station occurs (3-1), the base station sets a sequence number (3-
2). Here, the sequence number is set, for example, as a remainder of m (modulo m). Next, the head packet is transmitted by combining the identifier corresponding to the destination mobile station with the sequence number and the like (3-3), and subsequently the subsequent packet is generated (3
-4) and transmission (3-5) are performed.

The control flow of the mobile station in the first embodiment is shown in FIG. The mobile station always waits and receives the first packet in the downlink channel (4-1). If the first packet is received, the identifier in the first packet is read next (4-2), and if it matches the identifier assigned to the own station, the sequence number in the first packet is stored.
After that, subsequent packets are received (4-4). At this time, it is confirmed whether the sequence number given to each packet matches the sequence number notified by the first packet (4-5). The packet is fetched, but if they do not match, the packet is discarded (4-6) and the standby state is set.

(Embodiment 2) In this embodiment 2, during transfer of an uplink packet from a mobile station to a base station, the base station broadcasts an access control signal including a sequence number, and while the access control signal is broadcast. Described below is a method in which the mobile station transmits a packet group to which the sequence number is assigned. FIG. 5 shows the state of packet transfer when the packet multiplexing method according to the second embodiment is used, and FIG. 6 shows the configuration of the packet group according to the second embodiment. Further, FIG. 7 shows the structure of the access control signal.

The mobile station A, which intends to transmit the packet group (5-6), first transmits the first packet (5-5, 6-1) including the TEI assigned to itself. When the base station receives the first packet, it sets a sequence number for the packet group and changes the access control signal from a blank signal to a prohibition signal. The sequence number set at this time is written in the area 7-2 of the access control signal.
The distinction between blank line / prohibited signal is specified in 7-1. The mobile station A confirms that the access control signal has changed from the blank signal to the prohibition signal, stores the sequence number, and then transfers the subsequent packet (6-2). When the transmission is completed, the base station detects the transmission end flag and the like as in the case of the conventional technique 2, so that the prohibition signal immediately changes to the skyline signal.

Next, it is assumed that the mobile station B also transfers the packet group (5-8) by the same procedure, but the packet is not received by the base station due to an error in the wireless section in the slot 5-9. At this time, since the base station broadcasts the prohibition signal for a certain period of time without changing the sequence number even if the uplink packet is not received, the mobile station B looks at the sequence number of the prohibition signal and agrees with the stored sequence number. If so, the packet group can be continuously transmitted.
Further, when the downlink access control signal is not received by the mobile station due to an error in the wireless section during transmission of the mobile station (5-
10) looks at the sequence number of the prohibition signal received after the wireless line is restored, and if the sequence number matches the sequence number stored before the interruption, determines that transmission to the same packet group is permitted and Resume group reception.

FIG. 8 shows the operation flow of the base station in the second embodiment. When the base station receives the head packet from the mobile station (8-2) at the time of announcing the skyline signal (8-1), it sets the sequence number (8-3). Here, the sequence number is set as the remainder (modulo m) of m as in the first embodiment. Next, the base station reports (8-4) the set sequence number and prohibition signal. At this time, when the subsequent packet from the mobile station is received (8-5), the transmission end flag and the like are checked, and if the reception is not completed (8-9), the prohibition signal is continuously notified with the same sequence number (8-4). ) Do.
Further, even if the succeeding packet cannot be received in 8-5, the prohibition signal is continuously announced N0 times with the same sequence number, and the packet is still unreceivable (8-
In 7), the prohibition signal is changed to a blank signal. The transmission control of the blank line / prohibition signal when the packet is not received before the completion of the transmission is performed using the parameter n (8-1, 8-6, 8-7, 8).
-8).

FIG. 9 shows the operation flow of the mobile station in the second embodiment. Mobile station (9-1) where transmission packet group occurred
After confirming that the access control signal from the base station is a skyline signal (9-2), the head packet including the TEI of its own station is transmitted (9-3). If a prohibition signal is received on the subsequent downlink control channel (9-4), the assigned sequence number is stored (9-6), but if it is not received by the base station due to collision or the like, a random delay (9 −
After 5), the first packet is retransmitted. The mobile station receiving the prohibition signal transmits the subsequent packet (9-7). However, when transmitting the subsequent packet continuously, after receiving the prohibition signal (9-9), the assigned sequence number is stored. If the sequence numbers are collated (9-10) and they match, the subsequent packet is transmitted, but if the sequence numbers are different or the access control signal cannot be received for a while, a skyline signal is received. Case (9-11)
Restarts the transmission sequence from the beginning. If the transmission packet is the final packet, the transmission end flag is set and the packet is transmitted (9-8), and the standby state is entered.

In these embodiments, the present invention is applied to mobile communication.
Obviously, it is also applicable to the case where one wireless station communicates with a plurality of wireless stations.

[0024]

In the wireless packet multiplexing method according to the present invention, a series of wireless packets is grouped as a packet group, an identifier is given only to the first packet of the packet group, and at the same time, a sequence number is assigned to the packet group. By identifying the packet from the correspondence between the identifier and the sequence number, the increase in the packet overhead is mitigated, and even when the reception of the packet group is temporarily interrupted due to fading in the wireless section,
Since it is possible to identify the subsequent packet group by comparing the sequence numbers, it is possible to efficiently multiplex the packets, and it is possible to improve delay characteristics and throughput.

[Brief description of drawings]

FIG. 1 shows a packet multiplexing method according to a first embodiment.

FIG. 2 shows a configuration example of a packet group in the first embodiment.

FIG. 3 shows an operation flow of the base station in the first embodiment.

FIG. 4 shows an operation flow of the mobile station in the first embodiment.

FIG. 5 shows a packet multiplexing method according to the second embodiment.

FIG. 6 shows a configuration example of a packet group in the second embodiment.

FIG. 7 shows a configuration example of an access control signal in the second embodiment.

FIG. 8 shows an operation flow of a base station in the second embodiment.

FIG. 9 shows an operation flow of the mobile station in the second embodiment.

FIG. 10 shows a packet multiplexing method in LAPD (prior art 1).

FIG. 11 shows an operation example of a reservation reservation random access control method (prior art 2).

[Explanation of symbols]

1-1 Downlink (base station → mobile station) channel 1-2 Head packet to mobile station A 1-3 Packet group to mobile station A 1-4 Head packet to mobile station B 1-5 To mobile station B Packet group 1-6 Packet group received by mobile station A 1-7 Leading packet received by mobile station B to mobile station A 1-8 Leading packet received by mobile station A to mobile station B 1-9 Mobile station Packet group received by B 2-1 Head packet 2-2 Subsequent packet (packet group other than head packet) 2-3 Identifier (TEI) 2-4 Sequence number 2-5 Data 3-1 to 3-5 1. Operation flow of base station in No. 1 4-1 to 4-7 Operation flow of mobile station in the first embodiment 5-1 and 11-1 Downstream (from base station to mobile station) control channels 5-2 and 11-2 Upstream ( Mobile station → base station) Channel 5-3 a Access control signal (prohibition signal) 5-4 Access control signal (empty signal) 5-5 Mobile station A transmission start packet 5-6, 11-6 Mobile station A transmission packet group 5-7 Mobile station B transmission First packet 5-8, 11-7 Packet group for mobile station B transmission 5-9 Upstream packet transmission error 5-10 Downstream access control signal transmission error 6-1 First packet 6-2 Subsequent packet (packet other than first packet Group) 6-3 Identifier (TEI) 6-4 Data 7-1 Empty line / prohibition signal display area 7-2 Sequence number display area 8-1 to 8-9 Operation flow of base station in the second embodiment 9-1 9-11 Operation flow of mobile station in the second embodiment 10-1 D channel in I interface 10-2 Terminal A 10-3 Terminal B 10-4 Terminal C 10-5 Identifier (TEI) 10-6 Packet to terminal A 10-7 Packet to terminal C 10-8 Packet to terminal A 10-9 Packet to terminal B 10-10 Packet switch 11-3 Access control signal (prohibition signal / ACK) 11 -4 Access control signal (empty signal) 11-5 Access control signal (prohibit signal / NAK) 11-8, 11-9 Uplink transmission error

Claims (2)

[Claims] 1. When transmitting a message between a radio control station and a plurality of terminal stations under the control of the radio control station, the message is decomposed into a plurality of packets, and the radio control station and the plurality of terminal stations are divided. A packet is transmitted by transmitting the packet on a communication channel commonly used by the terminals, and when each terminal station previously matches the multiplex identifier individually assigned to the terminal station with the multiplex identifier added to the packet, the packet is captured. In the wireless packet communication system that multiplexes, the wireless control station or the terminal station that intends to transmit a message collects a plurality of the packets in advance to generate a packet group, and the packet is transmitted first in the packet group. A multiple identifier is given only to the first packet, and each packet has a sequence number indicating the packet group to which that packet belongs. Each packet constituting the packet group is continuously transmitted on the communication channel, and the receiving side takes in the first packet by the multiplex identifier, and the packet having the same sequence number as the first packet is the first packet. A wireless packet multiplexing method, wherein the packet is taken in as a packet belonging to the same packet group as the packet. 2. The wireless packet multiplexing method according to claim 1, wherein the number of bits indicating the sequence number is smaller than the number of bits indicating the multiplex identifier.