Two-Hop Transmissions in Asynchronous Channel-Hopping Cognitive Radio Wireless Networks With Buffer-Aided Relays

摘要

Due to physical constraints or channel impairments, direct (one-hop) communications among secondary nodes may not be possible in cognitive-radio wireless networks (CRWNs). In this letter, the rendezvous problems of two-hop transmissions using a relay node with buffer of different sizes in channel-hopping (CH) CRWNs are studied. A two-hop rendezvous protocol operating with suitable asynchronous CH sequences is proposed. A new performance metric, maximum time-to-rendezvous-with-relay (MTTRr), and throughput are derived for different buffer sizes. The studies find that (i) both MTTRr and throughput improve as the buffer size increases but see no further improvement beyond a certain buffer size, and (ii) the proposed two-hop rendezvous model has only slight performance penalties as compared to the conventional (one-hop) counterpart.