1 Rendezvous in Highly-dynamic CRNs: A Frequency Hopping Approach Mohammad J. Abdel Rahman, Hanif Rahbari, and Marwan Krunz Dept. of Electrical and Computer Engineering, University of Arizona, Tucson, AZ 85721 {mjabdelrahman, rahbari, krunz}@email.arizona.edu Technical Report TR-UA-ECE-2012-3 Last update: November 18, 2012 Abstract Establishing communications in a dynamic spectrum access (DSA) network requires communicating nodes to “rendezvous” before transmitting their data packets. Frequency hopping (FH) provides an effective method for rendezvousing without relying on a predetermined control channel. Current FH rendezvous designs have two main limitations. First, they do not account for fast primary user (PU) dynamics. Second, they mainly target pairwise rendezvous, and do not intrinsically support multicast rendezvous. In this paper, we first design a grid-quorum-based FH algorithm, denoted by NGQFH, for pairwise rendezvous. NGQFH can achieve efficient rendezvous under fast PU dynamics. It is also robust against node compromise. Using the uniform k-arbiter and Chinese Remainder Theorem quorum systems, we then propose three multicast rendezvous algorithms: AMQFH, CMQFH, and nested- CMQFH, which provide different tradeoffs between the time-to-rendezvous and robustness to node compromise. Our pairwise and multicast rendezvous algorithms are tailored for asynchronous and spectrum-heterogeneous DSA networks. To account for fast PU dynamics, we develop an algorithm for adapting the proposed FH designs on the fly. This adaptation is done through an optimal mechanism for channel sensing and assignment, and a quorum selection mechanism. Extensive simulations are used to evaluate our algorithms. Index Terms Control channel, dynamic frequency hopping, dynamic spectrum access, quorum systems. I. I NTRODUCTION Motivated by the need for more efficient utilization of the licensed spectrum and facilitated by recent regulatory policies [7], significant research has been conducted towards developing cognitive radio (CR) technologies for dynamic spectrum access (DSA) networks. CR devices utilize the available spectrum in a dynamic and opportunistic fashion without interfering with co-located primary users (PUs). The communicating entities of an opportunistic CR network are called secondary users (SUs). Establishing a communication link in a DSA network requires nodes to rendezvous. In the absence of centralized control, the rendezvous process needs to be carried out in a distributed manner. To address Some of the results in this paper were presented at the IEEE DySPAN Conference, Oct. 2012 [1].