Green Networking: Analyses of Power Consumption of Real and Complex IFFT/FFT used in Next-Generation Networks and Optical Orthogonal Frequency Division Multiplexing

The Orthogonal Frequency Division Multiplexing is a promising technology for the Next Generation Networks. This technique was selected because of the flexibility for the various parameters, high spectral efficiency, and immunity to ISI. The OFDM technique suffers from significant digital signal processing, especially inside the Inverse/ Fast Fourier Transform IFFT/FFT. This part is used to perform the orthogonality/De-orthogonality between the subcarriers which the important part of the OFDM system. Therefore, it is important to understand the parameter effects on the increase or to decrease the FPGA power consumption for the IFFT/FFT. This thesis is focusing on the FPGA power consumption of the IFFT/FFT uses in the OFDM system. This research finds a various parameters effect on FPGA power of the IFFT/FFT. In addition, investigate the computer software used to measure and analyse the FPGA power consumption of OFDM transceivers, and selects the target hardware used in the computer software. The researched parameters include the number of bits used in calculating the phase factor precision; Cyclic Prefix length effected on IP core IFFT, Subcarrier modulation type, word length width, Real and Complex Value IFFT, IFFT length, and subcarriers sampling frequency. The real value IFFT is proposed in 1987 and implemented in this thesis. These parameters above are discussed by comparing the result between the Real and Complex value IFFT used inside the OFDM system

Index mapping for prime factor algorithm of discrete cosine transform

This paper provides a direct derivation of the prime-factor-decomposed computation algorithm of an N-point discrete cosine transform for the number N decomposable into two relative prime numbers. It also presents input and output index mappings in the form of tables-namely, ri-, it-, nc-, nK-, and k-tables. The index mapping tables are useful for practical use of the prime-factor-decomposed computation of arbitrarily sized discrete cosine transforms