Application of Synchronized Multi-Hop Protocol to time-variable multi-rate and multi-hop wireless network

A multi-hop wireless network is considered promising for the next-generation communication systems because of its wide applicability to hard-to-wire circumstances. However, the throughput of a multi-hop wireless network based on the widely accepted IEEE 802.11 Standards is so low due to inter-flow and intra-flow collisions that further applications of the network are limited. To solve this problem, Synchronized Multi-Hop Protocol has been proposed in previous papers where the IEEE 802.11 Distributed Coordination Function (DCF) is modified slightly. The protocol has been proved to keep high throughput in practical cases where there are transmission failures and large interference ranges. In this paper, the protocol is applied to the environment where the transmission rate of data packets is time-variable and may be different from node to node. By theoretical analysis and simulation experiments, the throughput of the protocol is confirmed high and it is very close to its theoretical upper limit if the variation of the transmission rate is restricted within a certain range.