Cooperative VMIMO Routing In Wireless Network

Cooperative communication has been got much attention in the wireless communication as a new wireless communication technology.VMIMO(Virtual Multiple-Input Multiple-Output)is one instance of the cooperative communication modes;it combats multipath fading by exploiting multiple antennas from single-antenna nodes in the neighborhood to form the virtual antenna array,which improves the performance of the wireless networks.Cooperative routing algorithm is a cross-layer routing which combines the cooperative communication on the physical layer and the route selection on the network layer.Existing routing algorithms are mainly designed by discovering a non-cooperative route as a primal route and then specific nodes along the primary route are selected as the cooperative relays to build the cooperative path or dynamically building VMISO(Virtual Multiple-Input Single-Output)links hop by hop.The routing protocols use non-cooperative primary path to construct the cooperative path limit their performance to a large extent and the VMISO links do not make full use of the cooperative communication on the physical layer.To improve the performance of the wireless networks,this paper proposes cooperative VMIMO routing which finds out a cooperative path that not rely on the non-cooperative path and uses VMIMO technology.Considering that the effect of co-channel interference in wireless transmission on network performance and the multi-channel can reduce the interference between channels,cooperative VMIMO routing includes two parts:single interface single channel cooperative VMIMO routing protocol and multiple interfaces multiple channels cooperative VMIMO routing protocol.The single interface single channel cooperative VMIMO routing protocol dynamically establishes clusters hop by hop by transmitting the well designed route request control packets and the VMIMO technique is used to transmit data between clusters.The protocol includes constructing clusters and designing the control packets.Better route request and other control packets are designed to exchange between nodes to provide information building the clusters,and cluster head selection algorithm is started to select the best cluster head based on the information,and then the best cluster head recruits cooperative nodes to construct clusters.From the experiments we can find that the routing can improve the rate of discovering the path and reduce the energy consumption to save energy resource.The multiple interfaces multiple channels cooperative VMIMO routing protocol assigns the data transmission channels while building VMIMO path,multiple channels can effectively reduce the co-channel interference of wireless transmission on the cooperative routing.To reduce the interference between clusters,the routing adopts the channel assignment which selects the channel with the smallest interference as the transmission channel.When constructing the clusters,the protocol would consider the channel assignment to select the best cluster heads and cooperative nodes.After constructing the paths,the clusters can transmit the packets by using the VMIMO technology with different channels.The simulation results show that the routing protocol can use the multiple channels to transmit data without conflict to reduce the delay of transmission.