Effective ICI matrix and its compensation in SCFDMA communication system

DFT spread OFDMA popularly known as Single carrier frequency division multiple access (SCFDMA) is an emerging wireless standard and has received considerable attention because of its ability to incorporate advantages of single carrier modulation with OFDMA. Even though SCFDMA has low peak to average power ratio (PAPR) and resistance to frequency nulls of the channel, it inherits some drawbacks from OFDMA. Frequency synchronization between transmitter and receiver in mobile environment and resulting performance degradation is one such issue especially in uplink communication. After the standardization of SCFDMA as uplink standard for LTE, frequency synchronization is an active area of research. In this paper SCFDMA system is analysed in the presence of CFO and the results of analysis is utilized in framing an efficient representation to the multidimensional frequency synchronization problem as effective ICI matrix and a method to jointly compensate effective ICI matrix and equalize the channel is proposed based on minimum mean square error criterion and its performance is compared with the existing schemes.

I. Introduction

Frequency selective fading is a major impairment in wireless communication channel and OFDM/FDMA has been used very efficiently in overcoming the same. The major issue associated with OFDM is its large PAPR which forces transmitter power amplifier to work with large back offs and causes reduction in power efficiency. This power inefficiency is more prominent in uplink since mobile terminals are more power constrained. SCFDMA [1] developed as popular alternative to address the high PAPR of the OFDM and has been chosen as the uplink standard for LTE. SCFDMA combines the single carrier PAPR with the high multipath fading resistance of OFDMA and perform similar to OFDMA with same overall complexity [2] [3].