Abstract
In this paper, we explore physical layer cooperative communication in order to design network
layer routing algorithms that are energy efficient. We assume each node in the network is equipped with
a single omnidirectional antenna and that multiple nodes are able to coordinate their transmissions in
order to take advantage of spatial diversity to save energy. Specifically, we consider cooperative MIMO
at physical layer and multi-hop routing at network layer, and formulate minimum energy routing as a
joint optimization of the transmission power at the physical layer and the link selection at the network
layer. Using dynamic programming, we compute the energy consumption of the optimal cooperative
routing in different network scenarios, which shows energy savings of up to 55%, compared with
the optimal non-cooperative routing. As the network becomes larger, however, finding optimal routes
becomes computationally intractable as the complexity of the dynamic programming approach increases
as O(22n), where n is the number of nodes in the network. As such, we develop two greedy routing
algorithms that have complexity of O(n2), and yet achieve significant energy savings. Simulation results
indicate that the proposed greedy algorithms perform almost as good as the optimal algorithm and
achieve energy savings of more than 50% in the simulated scenarios.
Refereed
No
