Throughput and Delay Scaling of Cognitive Radio Networks with Heterogeneous Mobile Users

Abstract

We study the throughput and delay scaling laws of cognitive radio networks (CRN) with mobile primary and secondary users. They operate at the same time, space and share the spectrum. The primary users (PUs) have higher priority to access the spectrum while the secondary users (SUs) should access opportunistically. Furthermore, we consider a unique situation where both PUs and SUs move according to a General Heterogeneous Speed-restricted Mobility (GHSM) model. In this model, we define (h+1) heterogeneous moving patterns using a universal set T={T_i |0≤i≤h,A_i=n^(-i χ_0/h)}, where A_i determines the moving area of each pattern. The set of primary (secondary) moving patterns T^((p)) (T^((s) )) is a randomly and independently selected subset of T. We assign n (n^β, where β>1) primary (secondary) nodes to each moving pattern, and their initial positions are subject to a poisson point process. In addition, we have |T^((p) ) |~|T^((s) ) |=θ(h)= θ(logn). By proposing a cooperative routing strategy, we fully utilize the mobility heterogeneity of primary and secondary users and achieve near-optimal throughput and delay performance of order θ(poly log n) when χ_0≥β. In other cases, our transmission scheme shows advantages over [1] in delay performance of the primary network (PN) and over [2] in capacity of the secondary network (SN).