Differentiated QoS with Modified C/I Based Scheduling Algorithm
  Second-generation (2G) digital cellular systems constitute the majority of cellular communication deployed today. A variety of services of 2G systems has increased significantly and this will continue to grow even further in the emerging third-generation (3G) systems. Universal Mobile Telecommunication System (UMTS) is a third-generation mobile communications system which uses the Wide-Band Code Division Multiple Access (WCDMA) technique to support a wide variety of services, like speech, video telephony, Internet browsing, etc. These services require a wide range of Quality of Service (QoS) requirements. QoS is an important issue as the number of multimedia services increases day by day. Differentiated QoS methods allow the differentiation of users based on their priority levels and channel conditions so that the network can allocate the bandwidth for a particular request based on the QoS requirements. These requirements are controlled by Radio Resource Management (RRM) mechanisms. In this paper we have proposed two RRM algorithms which are modification to the existing scheduling algorithms. One is Prioritized C/I scheduling, which takes the priorities into consideration, and this algorithm serves the user with highest priority. Other algorithm is Modified Inverse C/I scheduling, which takes channel conditions into consideration and serves the users in degraded conditions, thereby improving QoS. The performance evaluation of two algorithms is done with EURANE extensions for NS-2. Simulation results shows the improvement in QoS for the users who are at equidistance from Base Station (BS) but requesting for different services by implementing Prioritized C/I scheduling and also for the users who are in degraded conditions by implementing Modified Inverse C/I scheduling when compared to Max C/I and Inverse C/I scheduling algorithm respectively. 
A. Divya and Sanjay Singh
cs.NI