Chapter 4
Capacity of Multirate Opportunistic Routing
The existing works on OR mainly focused on a single-rate system. Researchers have proposed several candidate selection and prioritization schemes to improve throughput or energy efficiency. However, there is a lack of theoretical analysis on the performance limit or the throughput bounds achievable by OR. In addition, one of the current trends in wireless communication is to enable devices to operate using multiple transmission rates. For example, many existing wireless networking standards such as IEEE 802.11a/b/g include this multirate capability. The inherent rate–distance tradeoff of multirate transmissions has shown its impact on the throughput performance of traditional routing (Awerbuch et al. 2006; Zhai and Fang 2006a,b). Generally, low-rate communication covers a long transmission range, while high-rate communication must occur at short range. It is intuitive to expect that this rate–distance tradeoff will also affect the throughput of OR because different transmission ranges also imply different neighboring node sets, which results in different spacial diversity opportunities. These rate–distance–diversity tradeoffs will no doubt affect the throughput of OR, which deserves careful study. To the best of our knowledge, there is no existing work addressing the throughput problem of OR in a multirate network.
In this chapter, we bridge these two gaps by studying the throughput bound of OR and the performance of OR in ...
