Distributed channel opportunity access method for wireless multicast network

Abstract

The invention discloses a distributed channel opportunity access method for a wireless multicast network. The method comprises the following steps: constructing a multicast communication system, determining an optimization model, and calculating the maximum throughput lambda * of the system offline; the information source node in each multicast group perceives and accesses a channel according to a competition mode; all sink nodes in the multicast group where the winning source node is located obtain a direct connection channel state through a training symbol sequence carried in the received RTS data packet, and obtain a corresponding reachable information transmission rate; each sink node selects the backoff time to send a CTS packet to the winning source node; if the winning information source node receives the CTS packet at the gamma moment or detects that a conflict occurs in the channel, the minimum information transmission rate Ri, min of the user in the multicast group where the winning information source node is located is obtained according to gamma; and if Ri, min is greater than or equal to lambda *, the winning information source node carries out multicast according to Ri, min, otherwise, all multicast group information source nodes start a new round of channel competition. According to the method, the global optimum of the average throughput rate of the network is ensured under the condition of reducing the signaling overhead.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a distributed channel opportunistic access method of a wireless multicast network. Background technique [0002] The existing network based on IEEE802.11 wireless transmission protocol mainly includes three communication modes: unicast, multicast and broadcast. Among them, there are existing researches and protocols on channel opportunistic access methods in distributed unicast communication mode. more adequate. In the distributed unicast communication mode, multiple source-sink communication pairs (also called users) share the channel for service transmission in a distributed manner, and multiple users access the channel through competition, and according to their directly connected channel status and The optimal access method determines whether it takes advantage of this opportunity. If the user who wins the competition gives up this transmission opportunity, al...

AI Technical Summary

Problems solved by technology

Under the current multicast communication mechanism, for a multicast communication mechanism with a given transmission rate, some users in the multicast group may not be able to receive data packets correctly due to poor channel conditions; according to the worst channel conditions of all users in the group The mechanism of transmitting at the achievable rate of the user will cause the system throughput to be low

At the same time, under this mechanism, since the source node needs to know the achievable transmission rate of the user with the worst channel state in the group, this process requires a large signaling overhead, which seriously wastes network channel resources.

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