Uplink Geographic Transmission Scheme for Mesh Networks

We consider communication in the uplink of a wireless mesh or sensor network. A group of mobile radios or sensors (hereafter called "nodes") have information to transmit to one or more access points (APs) (or "sinks"). When the channels from the nodes to the APs suffer from fading, direct transmissions to the APs may fail with a high probability, and packets may need to be relayed through other nodes. Under the conventional approach, routing, the relaying node is pre-selected, and fading may also cause a high probability of failure at the router. Thus, we propose a geographic approach, in which the relay is selected from those nodes that have received the packet correctly and can move it toward the AP. In this paper, we consider the design of a scheme to select which nodes should compete to relay the packet, and we develop and evaluate a protocol for this purpose. The results show that the geographic approach provides better performance than direct transmission, routing, and a previously developed geographic transmission scheme, especially when the signal-to-noise ratios are low and APs are sparse.