DCF protocol fairness guarantee method suitable for multi-hop ad hoc network

Abstract

The invention discloses a DCF protocol fairness guarantee method suitable for multi-hop ad hoc network. The fairness problem of a DCF protocol means that, in a multi-hop wireless ad hoc network, the protocol fails to effectively guarantee that a plurality of data streams of equal status share network channel bandwidth fairly. Based on the actual network condition that the detection scope of physical carriers of nodes is wider than the transmission scope thereof, the invention provides a DCF protocol fairness guarantee method suitable for multi-hop ad hoc network. The method comprises the steps that: on the basis of adaptive power-controlled RTS / CTS handshake process, data flow-occupied channel indexes reflecting the occupancy of the current channel bandwidth by the data flows are transferred, sending nodes are then required to comprehensively judge whether the current data flows occupy excessive channel resource according to own and neighboring data flows, and finally, the fair sharing of the channel bandwidth by a plurality of data flows is implemented by adopting the method for contention window adjustment and backoff in combination with the sending nodes. The effectiveness of the method is proved by data of simulation experiments in wireless network stimulating environment GloMoSim.

Description

technical field [0001] The invention belongs to the field of wireless networks, in particular to a DCF protocol fairness guarantee method suitable for multi-hop ad hoc networks. Background technique [0002] Ad hoc network is a new type of wireless network. It consists of a series of fully equal mobile nodes without any fixed or preset network facilities. Each node in the network is both a terminal and a router. Under the control of the channel access control (Medium Access Control, MAC) protocol, they access the wireless channel in a multi-hop sharing manner. Due to its fast, flexible, and high reliability, Ad Hoc networks are widely used in environments where fixed communication infrastructure cannot be provided, such as field communications, emergency rescue, field expeditions, and temporary meetings. [0003] IEEE 802.11 DCF (Distributed Coordination Function) is a standard protocol in wireless local area networks. It avoids conflicts between sending nodes through phys...

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Problems solved by technology

[0017] (3) when d 1 = 200m, d 2 =370m, the two sending nodes are not within the physical carrier detection range of the other party, and the physical carrier detection mechanism cannot provide synchronization for the sending node

[0018] (4) when d 1 = 200m, d 2 =500m, similar to the situation in (3), the two sending nodes are not within the physical carrier detection range of the other party, and the physical carrier detection mechanism cannot provide synchronization for the sending node

[0026] (3) When r=185m, R=385m, not only the physical carrier detection mechanism cannot provide a synchronization mechanism for the sending node, but also some sending nodes are still within the collision range of receiving nodes of other receiving / transmitting node pairs

[0027] (4) When r=250m and R=450m, the physical carrier detection mechanism cannot provide synchronization for the sending node, and carrier interference still brings unfair problems to the DCF protocol, and the value of FI is around 0.8

The disadvantage of this method is that it can only ensure that the node can obtain more channel bandwidth when the transmission fails, but it does not consider that when the node detects carrier interference through the physical carrier detection mechanism, the carrier detection mechanism will have a negative impact on the fairness of the DCF protocol. Impact

Therefore, the second type of improvement method is not suitable for the actual wireless ad hoc network environment

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