On Channel Hopping Sequences With Full Rendezvous Diversity for Cognitive Radio Networks

In cognitive radio networks, establishing a communication link between a pair of secondary users (SUs) requires them to rendezvous on a commonly available channel. Asynchronous channel hopping sequences with full rendezvous diversity (AFCHS) enable a pair of SUs to meet on every channel without requiring clock synchronization, and hence minimize rendezvous failures due to the appearance of primary user signals. Maximum conditional time-to-rendezvous (MCTTR) and maximum time-to-rendezvous (MTTR) are two primary metrics for evaluating the worst-case time-to-rendezvous of AFCHS under two extreme scenarios. In this letter, we derive lower bounds on the MCTTR and MTTR of AFCHS, and then propose a scheme with the minimum MCTTR and small MTTR. When the number of channels is odd, the proposed scheme has the minimum MTTR.