An Enhanced Fast Multi-Radio Rendezvous Algorithm in Heterogeneous Cognitive Radio Networks
Yeh-Cheng Chang, Cheng‐Shang Chang, Jang‐Ping Sheu · IEEE Transactions on Cognitive Communications and Networking · 2018
In this paper, we propose a fast rendezvous algorithm for a heterogeneous cognitive radio network (CRN), where each user might have more than one radio. One of the well-known problems for most multiradio rendezvous algorithms in the literature is that they are not backward compatible to users with onlyoneradio. To tackle this backward compatibility problem, our approach is a hierarchical construction that groups several time slots into an interval and proposes a novel algorithm to emulate two radios with a single radio in an interval. By doing so, at the interval level, each user behaves as if it had (at least) two radios. For the two-user rendezvous problem in a CRN with${N}$commonly labelled channels, the interval length is chosen to be${M}$time slots, where${M=2\lceil \text {log}_{2} (\lceil \text {log}_{2} N \rceil)\rceil +7}$. We show that the maximum time-to-rendezvous (MTTR) of our algorithm is bounded above by${9 M \lceil n_{1}/m_{1} \rceil \cdot \lceil n_{2}/m_{2} \rceil }$time slots, where${n_{1}}$(resp.${n_{2}}$) is the number of available channels to user 1 (resp. 2), and${m_{1}}$(resp.${m_{2}}$) is the number of radios for user 1 (resp. 2). For the setting that each user is equipped with only one radio and two available channels, our MTTR bound is only${M}$and that improves the state-of-the-art bound$16(\lceil \log _{2} \log _{2} N \rceil +1)$in the literature. By conducting extensive simulations, we show that for the expected time-to-rendezvous, our algorithm is also better than several existing multiradio algorithms.