Abstract
The rapid growth in demand for broadband wireless services coupled with the recent developmental work on wireless communications technology and the static allocation of the spectrum have led to the artificial scarcity of the radio spectrum. The traditional command and control model (Static allocation) of spectrum allocation policy allows for severe spectrum underutilization. Spectrum allocated to TV operators can potentially be shared by wireless data services, either when the primary service is switched off or by exploiting spatial reuse opportunities. This paper describes a hybrid access scheme based on CSMA/CA and TDMA MAC protocols for use in the TV bands. The approach allows secondary users (SU) to operate in the presence of the primary users (PU) and the OPNET simulation and modelling software has been used to model the performance of the scheme. An analysis of the results shows that, the proposed schemes protect the primary user from harmful Interference from the secondary user. In terms of delay, it was found that packet arrival rates, data rates and the number of secondary users have significant effects on delay.
Highlights
The rapid growth in demand for broadband wireless services and the development of wireless communications technologies have lead to radio spectrum scarcity
This paper describes a hybrid access scheme based on CSMA/CA and Time Division Multiple Access (TDMA) MAC protocols for use in the TV bands
This shows that 88.89% of the white spaces are utilized by the secondary user which is the white space utilization efficiency ; this has proven the effectiveness of the model for exploiting white space
Summary
The rapid growth in demand for broadband wireless services and the development of wireless communications technologies have lead to radio spectrum scarcity. The IEEE 802.22 standard for Wireless Regional Area Network (WRAN) that specifies how to and use unused spectrum (white space) in the TV broadcast band. Dynamic spectrum access (DSA) is a thrilling new concept that promises to provide flexibility to spectrum management, thereby, overcoming the limitations of traditional command and control model which gives a licensed user an exclusive right to a fixed and static amount of spectrum without taking account the time varying in the demand of the spectrum. The rule is aimed at regulating unlicensed secondary operation in the TV white space where the devices are divided into two categories: fixed and personal/portable as shown by Ghosh et al, [6]. This paper, describes hybrid MAC protocol which is based on partial IEEE 802.11 CSMA/CA and TDMA MAC protocols, designed to enable dynamic spectrum access (DSA) in cognitive radio networks.
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