A Zadoff-Chu Matrix Transform Precoding Based Orthogonal Frequency Division Multiplexing System

• Main Author: BAIG, IMRAN
• Format: Thesis
• Language: English
• Published: 2012
• Subjects: Q Science (General)
• Online Access: http://utpedia.utp.edu.my/21618/1/2012%20-COMPUTER%20%26%20INFORMATION%20SCIENCES%20-%20A%20ZADOFF-CHU%20MATRIX%20TRANSFORM%20PRECODING%20BASED%20ORTHOGONAL%20FREQUENCY%20DIVISION%20MULTIPLEXING%20SYSTEM%20-%20IMRAN%20BAIG.pdf; http://utpedia.utp.edu.my/21618/

Orthogonal-frequency-division-multiplexing (OFDM) schemes are most popular in the literature due to their ability to combat frequency selective fadingwhile providing high data-rate transmission. Today,OFDM has become part of several telecommunication standards that includes, among others, theupcoming 4G standards like long-term-evolution-advanced (LTE-A) and mobile worldwide interoperability for microwave access (Mobile-WiMAX).However, OFDM is not without some drawbacks.Major among them is the high peak-to-average power ratio (P APR) in the transmitted OFDM signals. High PAPR decreases the signal-to-quantization noise ratio (SQNR) of analog-to-digital converter (ADC)and digital-to-analog converter (DAC) while degrading the efficiency of the high-power-amplifier (HPA) in the transmitter. PAPR problem gets more severe in the uplink communications, since theefficiency of HPA is critical due to the limited battery power in a mobile terminal. The literature is replete with a large number of P APR reduction techniques. Among them, schemes like constellation shaping, phase optimization, nonlinear companding transforms, tone reservation (TR) and tone injection (TI), clipping and filtering, partial transmit sequence (PTS), selective mapping (SLM), and precoding based techniques are popular. The precoding based techniques, however, show great promise as they are simple linear techniques to implement without the need of any complex optimizations. Usually, the autocorrelation of the input sequence at OFDM modulator is related to the PAPR at its output. Use of precoder before the OFDM modulator affects that favourably.