Weak many vs. strong few: reducing BER through packet duplication in power-budgeted wireless connections

In this paper, we present new energy-aware techniques to lower the packet-level error rates of application-layer connections in wireless ad hoc networks. We consider a model in which each connection is allocated a fixed power budget, and ask: Is it better to use this power budget to send many duplicate packets (at lower power) or fewer packets (at high power)? We consider a scheme in which each application-layer connection is implemented at the physical level by an overlay network consisting of multiple parallel multi-hop paths. Data packets submitted at the connection source are checksummed and replicated. The destination delivers the first error-free copy of each packet, in order, dropping packets that are corrupt or duplicate. We compare our scheme with the traditional scheme in which the source transmits precisely one packet to the destination along a single minimum-hop path. We show that even when both schemes are constrained by identical power consumption bounds, our scheme can use duplication to attain significantly lower packet-level error rates in many common situations. We describe the relationship between packet error rate, the extent of duplication and the path lengths and show that the qualitative nature of the relationships change significantly, depending on available power budget.