Towards Backpressure Routing in Wireless Mesh Backhauls for Dense LTE Deployments

Future 5G networks will rely on heterogeneous deployment of micro eNodeBs, and is expected that wireless transport interfaces, deployed together with each eNodeB, will provide high-speed backhaul connectivity through the possibility to create an ad-hoc wireless mesh between the deployed micro eNodeBs. Therefore, the backhaul routing strategy will play a fundamental role in exploiting the backhaul resources. In this context, we aim to investigate the advantages and limitations of qualitatively different backhaul routing strategies as UEs download TCP and UDP content. In this paper, we compare a backpressure-based strategy that takes per-packet or per-flow basis (BP-MR) and traditional single path routing (OLSR). Ns-3 simulations show that the per-packet BP-MR variant enhances UDP performance by circumventing congestion but degrades TCP because of reordering. The per-flow BP-MR variant minimizes retransmissions by limiting the excessive reordering, and outperforms OLSR performance for both UDP backhaul traffic and TCP traffic.