A partially operated FFT/IFFT processor for low complexity OFDM modulation and demodulation of WiBro in-car entertainment system

Wireless broadband (WiBro) systems can provide high data rate wireless Internet access with personal subscriber station under the stationary or mobile environment. It is the orthogonal frequency division multiple access (OFDMA) in time division duplex (TDD) system with 768 useful subcarriers over a nominal bandwidth of 8.75 MHz at 2.3 GHz band and each frame is composed of 42 OFDM symbols, corresponding to 5 ms. For modulation and demodulation in the WiBro communication system, the fast Fourier transform (FFT) processing is the most speed and power consumption critical path. In this paper, we describe 4096 points FFT and inverse FFT processor for mobile in-car entertainment systems. To obtain low complexities, small computation power and distributed memory, partially operated over-sampling architecture is developed to meet the requirement of non-stopping and high-speed data throughput. From experiment results, we can show that our methods reduce the complexity about 37.8% and it is suitable to implementation in mobile devices for WiBro consumer application which is required small area and low-power such as multimedia data service.