Indian Journal of Science and Technology

Abstract

OVSF codes are used as channelization codes to support applications with different bandwidth requirements for the downlink of 3G mobile communication systems. The code assignment and reassignment problem focuses on the subject of minimizing the number of code relocations. OVSF (Orthogonal Variable Spreading Factor) code assignment method considering traffic characteristics in the WCDMA systems. The previously proposed Dynamic Code Assignment (DCA) scheme allows code reassignments to improve code utilization, but induces some service delay time to on-going calls, unlikely assumptions, including fixed service data rates and code-limited system capacities. Thus, OVSF code tree has insufficient number of available codes. Method/Statistical Analysis: In order to solve these problems and efficiently utilized OVSF codes, in this paper presents novel Glow warm Swarm Intelligence (GSO) based approach for active OVSF code assignment in WCDMA based networks. GSO algorithm is completely dependent on the behavioral pattern of glowworm (fireflies). The optimization algorithm requires an understanding of this behavioral pattern. The intensity of the emission of Lucifer in can be changed by glow worms which glow at different intensities. In order to improve the ability of the GSO it employs various phases until code allocation is completed. Results: By permitting only codes in the data branch to be reassigned the quality of service guarantee for real time traffic is possible. The simulation results shows that proposed GSO schemes not only guarantees the QoS but also gives high code utilization which is comparable with other existing techniques.
Conclusion/ Application: Performances of these methods are evaluated in terms of blocking probability, spectral efficiency, delay and throughput. In addition to this different GSO operator are tested under varying traffic loads to increase the overall system performance.