Opportunistic Multiple Access for Cognitive Radio Networks

Abstract

Abstract-In this paper, opportunistic multiple access to the under-utilized channel resources is investigated. Exploiting source burstiness, secondary cognitive nodes utilizes primary nodes' periods of silence to access the channel and transmit their packets. Cognitive relays could also make use of these silence periods to offer spatial diversity without incurring bandwidth efficiency losses. First, we consider the cognitive cooperation protocol and propose two different relay assignment schemes. Comparison between the proposed schemes is carried out through a maximum stable throughput analysis of the network. Then, secondary nodes access to the remaining idle channel resources is investigated. Queueing theoretical analysis and numerical results reveal that despite the fact that relays occupy part of the idle resources to provide cooperation, secondary nodes surprisingly achieve higher throughput in the presence of relays. The rationale is that relays help primary nodes empty their queues at faster rates, therefore, secondary nodes observe increased access opportunities to the channel.

Joint Spectrum Sensing and Access Evolutionary Game in Cognitive Radio Networks

“…Later, the authors in [14] extended the POMDP framework with learning the unknown statistics of the primary signals. In [12][15] [16], the SUs were modeled as separate queuing systems and a multiple-access strategy with cooperative relays was proposed. Wu et al in [17] proposed a multi-winner spectrum auction game to suppress the SUs' collision behaviors during spectrum access, while Li et al in [18] presented a coalitional game theoretic approach for the SUs' spectrum access.…”

“…13: end if 14: end for 15: • Update the probability of sensing and accessing, p s (t + 1) andp a (t + 1), using (79) and (80). 16: end for Based on (79)-(84), each SU can gradually learn the ESS. In Algorithm 1, we summarize the detailed procedures of the proposed distributed learning algorithm.…”

Multi-Channel Sensing and Access Game: Bayesian Social Learning with Negative Network Externality

“…After multi-channel sensing, SUs access primary channels for data transmission. Several spectrum access methods based on different mathematical models have been proposed, e.g., Markov decision process (MDP) based approaches [10]- [11], queuing theoretic approaches [12]- [14], and game theoretic approaches [15]- [17]. Moreover, the joint spectrum sensing and channel access problems were studied in [18]- [20].…”

Optimal queue scheduling for hybrid cognitive radio maintaining maximum average service rate under delay constraints

“…The authors of [5] then extended this research to a CR system supporting multiple PUs and a single SU in order to find the optimal transmit power and to characterize the relaying probability of the SU. The stability region of a CR network supporting multiple PUs, multiple relays and multiple SUs has been analysed in [6]. The authors of [4] to [6] employed the interweave paradigm, where the SUs have fewer opportunities to access the resources.…”

“…The stability region of a CR network supporting multiple PUs, multiple relays and multiple SUs has been analysed in [6]. The authors of [4] to [6] employed the interweave paradigm, where the SUs have fewer opportunities to access the resources. All these studies assumed that only a single queue was set up for each of the users, which fails to realistically represent the characteristics of multimedia video communication, and the results were conceived under the assumption of queuing stability, where the specific QoS constraints such as the delay tolerance were completely ignored.…”