att_abstract={{Measurement studies have shown that uneven and
dynamic usage patterns by the primary users of license based
wireless communication systems often lead to temporal and
spatial spectrum underutilization. This provides an opportunity
for secondary users (SU) to tap into underutilized frequency
bands provided that they are capable of cognitively accessing
the networks without colliding or impacting the performance of
the primary users (PU). When there are multiple networks with
spare spectrum, secondary users can opportunistically choose the
best network to access, subject to certain constraints. In cognitive
radio systems, this is referred to as the network selection problem
for secondary users.
This paper first formulate a Markov queuing model to obtain
the maximum allowable arrival rate of secondary users subject to
a target collision probability for the primary users. Based on this
model, a Collision-Constrained Network Selection (CCNS) method
is proposed to maximize secondary users throughput subject to
a given PU collision probability. Two more approaches, referred
as CCNS-Greedy and CCNS-Energy, are designed to furthermore
reduce collision probability and to decrease energy consumption
of secondary users, when the system is underloaded. However,
CCNS strictly relies on PU and SU traffic characteristics such as
inter-arrival time and service time. Then, MEAsurement-based
Networks Selection (MEANS) is proposed to perform network
selection for secondary users based on online measurement of
PU collision probability of each network, with the same objective
to regulate PU collision probability of each network below the
target value. Later, an enhanced MEANS (MEANS+) is designed
to improve SU throughput while not violating the target PU
collision probability. Simulation based extensive performance
evaluation has shown that the proposed schemes achieve the best
performance in terms of resulted PU collision probability, SU
throughput, and SU energy consumption, compared to Random
and Greedy strategies.}},
	att_authors={rj2124, lj1412, md6393},
	att_tags={Cognitive radio,  network selection},
	author={Chonggang Wang and Kazem Sohraby and Rittwik Jana and Lusheng Ji and Mahmoud Daneshmand},
	institution={{INFOCOM 2011}},
	title={{Network Selection for Secondary Users in Cognitive Radio Systems}},