POWER ALLOCATION IN SC-FDMA SYSTEM

Abstract

Single carrier frequency division multiple access (SCFDMA), a modified form of Orthogonal FDMA (OFDMA), is a promising technique for high data rate uplink communications in future cellular systems. SC-FDMA has similar throughput performance and essentially the same overall complexity as OFDMA. The main advantage of SC-FDMA is the peak-to-average power ratio (PAPR), which is lower than that of OFDMA. SCFDMA is currently a strong candidate for the uplink multiple access scheme in the Long Term Evolution(LTE 4G) of cellular systems under consideration by the Third Generation Partnership Project (3GPP). The main objective of this dissertation is the power allocation in SC-FDMA system. General ly,the optimization problem can be converted in to waterfilling problem subject to power constraints.Optimal power allocation algorithms are developed by utilizing Lagrange multiplier method and by using the Karush-Kuhn-Tucker (KKT) conditions[l].We will study a constant power allocation method by searching a threshold to improve the performance of SC-FDMA systems and compare the result with constant waterfihling method and equal power method