Optimal and Suboptimal Routing Based on Partial CSI in Random Ad-Hoc Networks

Abstract

In this paper we consider routing in random wireless-adhoc-networks (WANETs), where each node is equipped with a single antenna. Our analysis uses a proper model of the physical layer together with an abstraction of higher communication layers. We assume that the nodes are distributed according to a Poisson-point-process and consider routing schemes that select the next relay based on the geographical locations, the channel gains of its neighbor nodes and the statistical characterization of all other nodes. While many routing problems are formulated as optimization problems, the optimal distributed solution is rarely accessible. In this work, we present the exact optimal solution for the scenario analyzed. The optimal routing is given as a maximization of a routing metric which depends solely on the known partial channel state information (CSI) and includes an expectation with respect to the interference statistics. The optimal routing scheme is important because it gives an upper bound on the performance of any other routing scheme. We also present sub-optimal routing schemes that only use part of the available knowledge and require much lower computational complexity. Numerical results demonstrate that the performance of the low complexity schemes is close to optimal and outperforms other tested routing schemes.The authors are with the

Opportunistic Routing Based on Partial CSI in MIMO Random Ad-hoc Networks

“…This paper extends this work on SISO routing [20] to MIMO routing. Using multiple antennas, the network gains two important capabilities: spatial multiplexing (i.e., the ability to transmit multiple data streams in parallel) and interference mitigation (i.e., the ability to combine the signals from different receive antennas such that the effect of the interference from undesired transmissions is lessened).…”

“…To further demonstrate the advantages of our novel routing scheme, we performed a complete network simulation in which messages were routed from sources to destinations according to the mechanism described in Subsection II-C (also see in [20]). The simulation included an average of 100 nodes uniformly distributed over a simulation area of 1000m 2 where each node was equipped with two antennas.…”

“…The optimal routing scheme given the local knowledge is defined by the functions f (•) and κ(•) that maximize the conditional ADORP (the argument of the expectation in (6)). However, unlike the single antenna case [20], Equation (6) does not lead directly to an optimal routing function. This is because J i,j,k depends on the number of streams selected by each of interfering users.…”

“…This type of algorithm is known as opportunistic relaying. Opportunistic relaying (e.g., [15]- [20]) was shown to outperform traditional routing (such as nearest-neighbor). To date, however, opportunistic relaying has not been investigated for MIMO multi-hop networks.…”

“…Recently, in a study that considered single antenna (SISO) WANETs using the ADORP routing performance metric, we derived a routing scheme that maximizes the network throughput based on local knowledge at each node [20]. We also conducted complete network simulations in which messages were routed from sources to destinations, and showed that the ADORP provides a good characterization of the capability of the network to deliver messages from sources to destinations.…”