Signal Processing for Cognitive Radios

14

DYNAMIC SPECTRUM LEASING IN COGNITIVE RADIO NETWORKS

14.1 INTRODUCTION

Dynamic spectrum leasing (DSL) refers to the dynamic spectrum sharing (DSS) approach in which primary users proactively facilitate the spectrum access by secondary cognitive radios. In contrast to DSA of the previous two chapters, wherein primary users were assumed to be completely oblivious to the spectrum sharing process, in DSL, there is an explicit incentive for the primary users to allow such secondary access.

Similar to DSA, DSL-based spectrum coexistence can also be achieved in the form of either spectrum underlay or spectrum overlay. In DSL, primary users dynamically adjust the extent to which they are willing to lease their spectrum (see Figure 3.8). In return, they receive a leasing payment, called a reward or a payback, that is proportional to the amount of allowed spectrum access. This reward can be considered as a monetary reward or an in-kind payment. An in-kind payment implies the primary users, or the system, receiving a certain cooperation from the secondary users that will help improve the primary communications performance. In the case of monetary rewards, it can be taken as a metric that can be converted into monetary terms. For our purpose, of course, we do not necessarily need to consider an exact monetary reward function. Instead, a certain technically and economically meaningful metric would be sufficient. In this chapter, we will discuss example DSL implementations based on both ...