Performance Evaluation of Uplink Multiple Access Techniques in LTE Mobile Communication System

Abstract: The User Equipments (UE) nowadays are able to provide various internet applications and services that raise the demand for high speed data transfer and Quality of Service (QoS). Accordingly, next generation mobile communication systems driven by these demands are expected to provide higher data rates and better link quality compared to the existing systems. Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) are strong multiple access candidates for the uplink of the International Mobile Telecommunications-Advanced (IMT-Advanced). These multiple access techniques in combination with other promising technologies such as multi-hops transmission and Multiple-Input-Multiple-Output (MIMO) will be utilized to reach the targeted IMT-Advanced system performance. In this thesis, OFDMA and SC-FDMA are adopted and studied in the uplink of Long Term Evolution (LTE). Two transmission scenarios are considered, namely the single hop transmission and the relay assisted transmission (two hops). In addition, a hybrid multiple access technique that combines the advantages of OFDMA and SC-FDMA in term of low Peak-to-Average Power Ratio (PAPR) and better link performance (in terms of Symbol Error Rate (SER)) has been proposed in relay assisted transmission scenario. Simulation results show that the proposed hybrid technique achieves better end-to-end link performance in comparison to the pure SC-FDMA technique and maintains the same PAPR value in access link. In addition, a lower PAPR is achieved compared to OFDMA case, which is an important merit in the uplink transmission due to the UE’s power resources constraint (limited battery power).