Personal and Ubiquitous Computing (2018) 22:471–487
User social activity-based routing for cognitive radio networks
· Zhipeng Cai
· Xiaoming Wang
· Lichen Zhang
· Peng Li
· Zaobo He
Received: 12 July 2017 / Accepted: 30 October 2017 / Published online: 12 February 2018
© Springer-Verlag London Ltd., part of Springer Nature 2018
The social activities of Primary Users (PUs) and Secondary Users (SUs) affect actual accessible whitespace in Cognitive
Radio Networks (CRNs). However, the impacts of primary activities on available whitespace have been extensively
investigated due to the dominating priority of PUs, while the impacts of secondary activities on actual accessible whitespace
have been ignored. Therefore, we propose to incorporate the primary and secondary activities in the analysis and decision of
the accessible whitespace, namely, both the dominance of PUs over SUs and the competitions among SUs are simultaneously
taken into account. Specifically, we first approximate primary activity probability based on the real datasets of mobile phone
usage records, then the spectrum opportunity between a pair of communication SUs is deduced based on primary activities.
Next, we infer the access probability limit of SUs successfully accessing the whitespace according to the primary activity
probability, and depict the secondary activity probability from the views of social activity patterns and social networks
respectively. Furthermore, the actual accessible probability of whitespace is given by introducing the competitions among
SUs. Finally, a greedy routing algorithm, considering the accessible whitespace and the distance to the destination, is
proposed to verify our idea. The experiment results based on the real datasets demonstrate the correctness of our analysis
and the advantages of the proposed algorithm.
Recently, the efficient utilization of wireless spectrum is
being highly desired. However, the inefficient usage of
licensed spectrum and limited availability of unlicensed
spectrum are frustrating, which is aggravated by the recent
growth of wireless devices and novel applications. This
necessitates Cognitive Radio Networks (CRNs), which
enables the Secondary/unlicensed Users (SUs) to share
the licensed spectrum opportunistically without interfering
with Primary/licensed Users (PUs) . Specifically, SUs
are allowed to access the unused licensed spectrums, i.e.
The short version of this manuscript is in IIKI 2016 .
Zhipeng Cai is a Senior Member, IEEE
Key Laboratory for Modern Teaching Technology,
Ministry of Education, Xi’an 710062, China
School of Computer Science, Shaanxi Normal University,
Xi’an 710119, China
Department of Computer Science, Georgia State University,
Atlanta, GA 30303, USA
whitespace or spectrum holes which are not occupied by
PUs. Once PUs appear to demand the licensed spectrum,
SUs must vacate the spectrum.
As stated by the Federal Communications Commission
(FCC), the utilization of the licensed spectrum ranges from
15% to 85% from the aspects of time and space . It
is obvious that social activities of humans, including the
characteristics of human behaviors [3, 4], play an important
role in the above variations of spectrum utilization. Actually,
the available whitespace depends on how the PUs use the
spectrum in practical applications, e.g., the beginning and
ending times, and continuous or discontinuous usages. More
importantly, the aforementioned dependents are determined
by the social activities of PUs, i.e., primary activities.
Therefore, it is reasonable to analyze the whitespace
through modeling primary activities, which addresses the
primary concerns such as the routing design and network
deployment in CRNs.
Although the available whitespace for SUs is determined
by the primary activities, the actual accessible whitespace
for SUs, e.g., via the competitions with other SUs, also
relies on the social activities of SUs, i.e., secondary activ-
ities. For example, PUs are less active from 1:00am to
5:00am, which means more whitespace is available for SUs.
However, if SUs are very active during that time period, the