Linda Meylani

Enhancement of MC-CDMA performance system using Rotated Modulation

The transmission system with high data rate and high mobility is needed. However, the system is susceptible to frequency selective fading and fast fading. We propose MC - CDMA system with Rotated Modulation that be able to solve the problems. MC - CDMA is a combination of OFDM and CDMA system which offer high spectral efficiency. However, this system still requires high power, so in this study Rotated Modulation is added to reduce the power. Rotated Modulation implements rotating signal constellation and use quadrature and inphase interleaver. The simulations result show MC - CDMA with Rotated Modulation produce a system that require less power compared with MC-CDMA non Rotated Modulation systems.

Utilizing mean greedy algorithm using user grouping for chunk allocation in OFDMA systems with carrier aggregation

In this paper, utilizing user-order chunk allocation algorithm for OFDMA systems using carrier aggregation environment is proposed and evaluated. Chunk allocation algorithm is performed based on mean greedy algorithm which has low complexity. In order to adopt this algorithm to those system, all users are divided into a certain group in accordance with the number of available aggregated carriers. The simulation results are shown that the performance and time complexity of the proposed scheme is same with the system without user grouping. Therefore, the proposed scheme could be considered to realize in LTE-Advanced platform.