A time-efficient rendezvous algorithm with a full rendezvous degree for heterogeneous cognitive radio networks

Abstract

Channel rendezvous is a prerequisite for secondary users (SUs) to set up communications in cognitive radio networks (CRNs). It is expected that the rendezvous can be achieved within a short finite time for delay-sensitive applications and over all available channels to increase the robustness to unstable channels. Some existing works suffer from a small number of rendezvous channels and can only guarantee rendezvous under the undesired requirements such as synchronous clock, homogeneous available channels, predetermined roles and explicit SUs' identifiers (IDs). In this paper, to address these limitations, we employ the notion of Disjoint Set Cover (DSC) and propose a DSC-based Rendezvous (DSCR) algorithm. We first present an approximation algorithm to construct one DSC. The variant permutations of elements in the ingeniously constructed DSC are then utilized to regulate the order of accessing channels, enabling SUs to rendezvous on all available channels within a short duration. We derive the theoretical maximum and expected rendezvous latency and prove the full rendezvous degree of the DSCR algorithm. Extensive simulations show that the DSCR algorithm can significantly reduce the rendezvous latency compared to existing algorithms.

Guaranteed rendezvous for cognitive radio networks based on cycle length

“…Such as, the HH algorithm that assumes the consecutive channel labels in [7], the unguaranteed probability based CH algorithm in [13], the MTP algorithm proposed in [17] and the DCSR algorithm in [15].…”

“…While the non-oblivious channel labeling assumes that the two nodes share the same labeling policy on the global available channels, and the two nodes share the same set of globally available channels. Both the DCSR algorithm in [15] and the MTP algorithm with lower efficiency in [17] are achieved under the nonoblivious model.…”

“…But two problems exist in this paper, firstly, the labels of the globally available channels is a consecutive number sequence. Secondly, as observed in [15], the performance of MTP is not highly efficient even if the spectrum is fully available. The DSCR algorithm in [15] is based on a set of globally labeled available channels, so the same channel label (or index) of a channel is used between a pair of nodes.…”

“…Secondly, as observed in [15], the performance of MTP is not highly efficient even if the spectrum is fully available. The DSCR algorithm in [15] is based on a set of globally labeled available channels, so the same channel label (or index) of a channel is used between a pair of nodes. In other words, they do not consider the oblivious setting for channel labeling.…”

Multiple Radios for Fast Rendezvous in Heterogeneous Cognitive Radio Networks

“…Prior to data transmission, SUs need first learn about the presences of their target SUs and establish communication links with them. This procedure, which is referred to as channel rendezvous, plays a critical role in configuring a CRN [6]. Existing solutions for the rendezvous problem can be classified into aided rendezvous schemes and unaided rendezvous schemes.…”