Constructing Virtual Backbone with Bounded Diameters in Cognitive Radio Networks

Abstract

Cognitive radio networks (CRNs) have been recognized as a promising communication paradigm to permit cognitive users (CUs) to access spectrum bands, which are allocated to primary users (PUs). Virtual backbones have brought about many benefits for routing and data transmission in traditional wireless networks, which also have been studied broadly. Virtual backbones also play an important role in CRNs, which would help increase the efficiency of routing and data transmission. The smaller virtual backbones require less maintenance cost. Unfortunately, computing the minimum virtual backbone is NP-hard, meanwhile, in CRNs, due to the stochastic activities of PUs, the links between CUs are unstable. Therefore, there exists a large probability that the virtual backbone becomes invalid, which incurs many works on CRNs concerning about the maximum lifetimes of virtual backbones. However, people neglect other important metrics of the network, such as diameter and average hop distances between two communication nodes. In this paper, we construct the virtual backbone with bounded diameter in CRNs, which constrains the length of the paths on which messages travel. The virtual backbones with bounded diameters save energy of the network and decrease the probability of packet loss and error. We present a centralized algorithm based on the idea of BFS tree to construct a virtual backbone with bounded diameter. To the best of our knowledge, this is the first work to address a virtual backbone satisfying bounded diameter in CRNs.