The Research Of Cooperative Routing In Wireless Networks

In the modern society, multiple input multiple output antenna technology（MIMO） is widely used in many fields because of its advantage of suppressingchannel fading effects. Since mobile terminal has strict requirement of power, weightand volume, most of the multiple antennas are installed in base station rather thanmobile terminal now. As a kind of virtual multiple antenna diversity technology,cooperative diversity technology make the mobile terminals with single antenna tocommunicate with each other distributly by using the broadcast character. As a result,achieves the performance gain and combats the multipath fading effects.In this paper, cooperative routing algorithms based on throughput are proposedto maximize the throughput of Ad Hoc network. Cooperative diversity technology isconnected with routing. In each hop, the best relay is selected to help the sendertransmit message, which make the receiver get diversity gain and the network’sperformance is improved. In the fixed relays cooperative algorithm, a shortest-pathroute is established by destination sequenced distance vector （DSDV）firstly.According to the neighbor node table, the common neighbor nodes of this node andthe node of next hop are selected to establish the relay set. Then, according to the linkthroughput, fixed relays are chosen to transmit data. The transmission power of thenodes is adjusted to guarantee that every link has the same transmission power. In theadaptive cooperative routing algorithm, at most two relays are selected adaptively hopby hop to help the transmission and the transmission power of sender and relays areadjusted dynamically according to the number of selected relays. Simulation resultsshow that with the same transmission power, the cooperative routing algorithms withfixed relays can improve the network throughput compared with the non-cooperativeDSDV routing and the adaptive cooperative routing algorithm can achieve greaterimprovement of network throughput. In addition, the network throughput withdifferent network sizes and the maximum mobility rates of node is simulated.