Design of Optimum Physical Layer Architecture for a High Data Rate LTE Uplink Transceiver Dr. G. Indumathi Department of Electronics and Communication Engineering, Mepco Schlenk Engineering College, Sivakasi, India. Abstract-The Third Generation Partnership Project (3GPP) provides the Long Term Evolution (LTE) standards for the fourth generation (4G) wireless communication systems. Single Carrier Frequency Division Multiple Access (SC–FDMA) and Orthogonal Division Multiple Access (OFDMA) are the two major techniques used in LTE. The main drawback of OFDMA over SC–FDMA is its high peak to average power ratio (PAPR). Hence OFDMA is used in the downlink of the fourth generation (4G) wireless communication systems for its high spectral efficiency and high PAPR. SC–FDMA is used in the uplink of the fourth generation (4G) wireless communication systems since it is more power efficient. The main objective of this paper is to design optimum physical layer architecture of a high data rate LTE uplink transceiver using SC–FDMA multiple access scheme with error correction mechanism using Low dense parity check codes (LDPC) to provide lesser Bit Error Rate (BER) and avoiding packet loss by Interleaving. The optimum physical layer architecture for the fourth generation (4G) wireless communication systems is chosen by comparing the LDPC coded SC–FDMA with the LDPC coded OFDMA. The chosen architecture must be more power efficient and support high data rates, which is the main prerequisite for the mobile user. Keywords—interleaving, low dense parity check codes, SC– FDMA, PAPR, bit error rate. I. INTRODUCTION Long Term Evolution (LTE) is a beyond 3G system conceived with the objective of providing substantial advances in terms of data rates, Quality of Service (QoS) provisioning and cost reduction for users and operators with respect to currently available 3G systems. The uplink of the LTE wireless communication systems require low Peak to Average Power Ratio (PAPR), low Bit Error Rate (BER), high data rate, high spectral efficiency, high reliability, low latency and low computational complexity [7]. The LTE wireless transmission can be made reliable by using interleaving process [1]. Interleaving will improve the performance of the system by avoiding packet loss [19]. The probability of error in the received packets is reduced by using interleaving [2]. Using error correction codes after interleaving will further improve the rigidity of the system [6]. D. Allin Joe Department of Electronics and Communication Engineering, Mepco Schlenk Engineering College, Sivakasi, India. P. Jagatheeswari and M. Rajaram (2011) diagnosed that low dense parity check codes (LDPC) shall be used in higher order modulations like 64 QAM [13]. LDPC will increase the spectral efficiency and reliability by approaching the theoretical Shannon limit while ensuring reduced complexity [5]. With structured parity–check matrices, it can reduce both the encoding and decoding complexity [6]. Bit error rate (BER) performance of the LDPC codes is better and is more power efficient [18]. In this paper, the LTE system is made reliable by using interleaving process in the input packets. Then LDPC codes are used to improve the BER of the system [10]. An advantage with the LDPC codes is that the decoders will be implemented in parallel and it has significant advantages while considering long codes [9]. The comparison of BER between the higher order modulations along with LDPC codes is done to fulfill the high data rate requirement of the system. Dhirendra Kumar Tripathi, S.Arulmozhi Nangai and R. Muthaiah (2011) have implemented scalable bandwidth single carrier frequency domain multiple access transceiver for the fourth generation wireless communication using FPGA [3]. They proposed SC–FDMA is better choice than OFDMA for LTE uplink transmission. They haven`t compared SC– FDMA over OFDMA in their work but they projected QAM modulation can be used instead of QPSK to achieve high data rates. Another approach is done by Muhammad Mokhlesur Rahman and Shalima Binta Manir (2012) to determine the performance analysis of SC–FDMA and OFDMA in LTE Frame Structure [11]. It is inferred from their work that SC–FDMA is less sensitive to frequency offset than OFDMA. SC–FDMA has less PAPR ratio than OFDMA and hence it is more power efficient than OFDMA. They have not used any error correction codes in their analysis. Power saving is essential during the uplink transmission since it involves the mobile stations [15]. For the multiple access techniques used in LTE, the maximum average amount of power required is calculated by using PAPR value [16]. The PAPR value is calculated by demonstrating a Complementary Cumulative Distribution Function (CCDF) Proceedings of 2013 International Conference on Green High Performance Computing March 14-15, 2013, India 978-1-4673-2593-6/13/$31.00 ©2013 IEEE ICGHPC 2013