BER Performance Analysis of Frequency-Hopping and Direct-Sequencing Spread Spectrum for Cognitive Radio Networks

Cognitive radio is an encouraging technology for future wireless communication networks. Due to the rapid increase in wireless services, the RF spectrum is going through a scarcity problem. This has forced mobile operators to participate in multimillion dollar auctions to reserve some spectrum resources. Cognitive radio tries to solve this scarcity problem by effectively using the unused portions of the spectrum. FHSS and DSSS are two spread spectrum technologies used for cognitive radios. In this paper, both techniques have been discussed extensively. DSSS accesses spectrum in a sequence whereas FHSS accesses spectrum by a hopping sequence and thus provide immunity to interference and jamming signals. Also, they have been concatenated to cognitive radio and analyzed to find which spread spectrum technology provides better communication. Simulations have been performed in MATLAB environment and results are shown in the form of number of error bits (BER) generated for a range of SNR values. KeywordsCognitive radio networks, spectrum sensing, spread spectrum, frequency hopping, direct sequence, DSSS, FHSS, spreading code, BER. __________________________________________________*****_________________________________________________