Energy Optimized Transmission Strategy in CDMA Reverse Link: Graph Theoretic Approach

Abstract

We investigate rate scheduling and power allocation problem for a delay constrained CDMA systems. Specifically, we determine an energy efficient scheduling policy, while each user maintains the short term (n time slots) average throughput. We consider a multirate CDMA system where multirate is achieved by multiple codes. Each code can be interpreted as a virtual user. The aim is to schedule the virtual users into each time slot, such that the sum of transmit energy in n time slots is minimized. We then show that the total energy minimization problem can be solved by a shortest path algorithm. We compare the performance of the optimum scheduling with that of TDMA-type scheduling. May 22, 2015 also to reduce the environmental effects. Many researches have investigated to achieve green communications [1∼2] . Scheduling plays an important role in enabling efficient transmission for wireless systems with multiple users [3∼4] . Scheduling users in a CDMA system have been investigated to support applications with high bandwidth and strict latency requirements [5∼6] . Energy efficient power and rate allocation for Direct Sequence (DS)-CDMA systems are investigated in [5], whereas reference [6] investigates the optimal and suboptimal solutions to (1069)