On Reliable Key Performance Indicators in Cognitive Radio Networks

Network serveability (NS), which considers both channel availability (CA) and service retainability (SR), is a key indicator to concisely express the performance of cognitive radio networks (CRNs). However, CA cannot guarantee connection setup if receiver’s accessibility ( RxA ) is neglected. Likewise, SR yields imperfect results if RxA is ignored. As such, the two rather incomplete performance indicators misrepresent NS and lead to an overestimated satisfaction level of users. Aiming at reliable and concise analysis of CRNs’ performance, this letter introduces the concept of connection availability (CoA), which encompasses both CA and RxA for a user. Besides, it introduces service maintainability (SM), which incorporates the impact of RxA into SR. Consequently, the performance is represented more concisely through network serviceability (NeS), a concept we introduce to consider both CA and SM. We show that CoA, SM, and NeS diverge with various proportions from CA, SR, and NS, respectively, under variable traffic loads and channel failure rates. This indicates the degree of performance difference RxA introduces, and provides network designers the basis for dependable CRN budgeting.