Optimizing Average-Maximum TTR Trade-off for Cognitive Radio Rendezvous

TL;DR

This paper proposes a hybrid channel hopping protocol for cognitive radio networks that balances average and maximum TTR, improving rendezvous performance by combining the strengths of random and sequence-based methods.

Contribution

It introduces a novel framework that leverages neighbor discovery principles to create hybrid protocols balancing average and maximum TTR in CR rendezvous.

Findings

Significantly reduces average TTR compared to traditional protocols.

Maintains a low upper bound of TTR while achieving high rendezvous diversity.

Analytical and simulation results validate the effectiveness of the proposed framework.

Abstract

In cognitive radio (CR) networks, "TTR", a.k.a. time-to-rendezvous, is one of the most important metrics for evaluating the performance of a channel hopping (CH) rendezvous protocol, and it characterizes the rendezvous delay when two CRs perform channel hopping. There exists a trade-off of optimizing the average or maximum TTR in the CH rendezvous protocol design. On one hand, the random CH protocol leads to the best "average" TTR without ensuring a finite "maximum" TTR (two CRs may never rendezvous in the worst case), or a high rendezvous diversity (multiple rendezvous channels). On the other hand, many sequence-based CH protocols ensure a finite maximum TTR (upper bound of TTR) and a high rendezvous diversity, while they inevitably yield a larger average TTR. In this paper, we strike a balance in the average-maximum TTR trade-off for CR rendezvous by leveraging the advantages of both random and sequence-based CH protocols. Inspired by the neighbor discovery problem, we establish a design framework of creating a wake-up schedule whereby every CR follows the sequence-based (or random) CH protocol in the awake (or asleep) mode. Analytical and simulation results show that the hybrid CH protocols under this framework are able to achieve a greatly improved average TTR as well as a low upper-bound of TTR, without sacrificing the rendezvous diversity.