Introduction

In Chapter 4, we basically studied how to assign time slots to communication links in quasi-static networks (e.g., WMNs and WSNs) such that the scheduled transmissions are interference-free and the scheduling period is minimized (thus maximizing the throughput). We assumed that there is only one spectrum used by all links in the network. In this chapter, we mainly focus on multichannel networks when there are multiple spectrums available for wireless terminals in the network. The wireless devices may have multiple wireless NICs or just a single wireless NIC. Because close by mesh routers compete for certain wireless channels, the capacity of a WMN will be increased tremendously when the single channel is extended to multiradio, multichannel, and multihop. For example, if two nodes vi and vj could communicate with each other by channel f1, and both nodes have at least one more available NIC that could operate on another channel f2, if f2 is also available for both nodes, vi and vj could use both f1 and f2 to communicate simultaneously. When such cases are applied to more wireless nodes, the throughput of the wireless network will be increased tremendously.

On the other hand, with recent fast-growing spectrum-based services and devices, the remaining spectrum available for future wireless services is being exhausted, known as the spectrum-scarcity problem.