Title
The asymptotic throughput and connectivity of cognitive radio networks with directional transmission
Abstract
Throughput scaling laws for two coexisting ad hoc networks with m primary users (PUs) and n secondary users (SUs) randomly distributed in an unit area have been widely studied. Early work showed that the secondary network performs as well as stand-alone networks, namely, the per-node throughput of the secondary networks is θ (1√(n log n). In this paper, we show that by exploiting directional spectrum opportunities in secondary network, the throughput of secondary network can be improved. If the beamwidth of secondary transmitter (TX)'s main lobe is σ = o(1/ log n), SUs can achieve a per-node throughput of θ (1√(n log n) for directional transmission and omni reception (DTOR), which is θ (log n) times higher than the throughput without directional transmission. On the contrary, if θ = ω (1/ log n), the throughput gain of SUs is 2π/δ for DTOR compared with the throughput without directional antennas. Similarly, we have derived the throughput for other cases of directional transmission. The connectivity is another critical metric to evaluate the performance of random ad hoc networks. The relation between the number of SUs n and the number of PUs m is assumed to be n = mβ. We show that with the HDP-VDP routing scheme, which is widely employed in the analysis of throughput scaling laws of ad hoc networks, the connectivity of a single SU can be guaranteed when β > 1, and the connectivity of a single secondary path can be guaranteed when β > 2. While circumventing routing can improve the connectivity of cognitive radio ad hoc network, we verify that the connectivity of a single SU as well as a single secondary path can be guaranteed when β > 1. Thus, to achieve the connectivity of secondary networks, the density of SUs should be (asymptotically) bigger than that of PUs.
Year
DOI
Venue
2014
10.1109/JCN.2014.000034
Journal of Communications and Networks
Keywords
Field
DocType
Throughput,Interference,Ad hoc networks,Cognitive radio,Routing,Batteries,Directional antennas
Transmitter,Binary logarithm,Computer science,Computer network,Main lobe,Directional antenna,Throughput,Wireless ad hoc network,Beamwidth,Cognitive radio
Journal
Volume
Issue
ISSN
16
2
1229-2370
Citations 
PageRank 
References 
3
0.38
14
Authors
5
Name
Order
Citations
PageRank
Zhiqing Wei110728.35
Zhiyong Feng2794167.21
Qixun Zhang315728.59
Wei Li442256.67
T. Aaron Gulliver5864143.47