Mobility Support for Cooperative Wireless Networks

In a cooperative network, by combining multiple copies of the same packet that are received either simultaneously (i.e., same time-slot) or non-simultaneously (i.e., different time-slot), the aggregate power level of the cooperatively transmitting set, required to achieve reliable reception at the receiver node, can be considerably lowered. This approach is especially advantageous for networks, where the number of nodes in the network, the network density, or the potential for wireless broadcasting advantage is high. In such networks, required transmit energy can be considerably reduced by routing packets over cooperative paths. Since the success of cooperation strictly depends on the selection of the appropriate power levels for each cooperating node, cooperative routing becomes difficult in networks where the nodes are mobile. In such networks, we need to select paths that can maximize the energy savings averaged over the connection time rather than the ones that only maximize savings at the current time. For this reason, we need to design routing protocols that takes into account the mobility characteristics within the network. In this paper, we propose a cooperative routing protocol that can improve the reliability level in the network against mobility variations.