Interference reduction in MB-OFDM ultra wideband systems using Turbo code

All around the globe, various research oriented work is going regarding the optimization of orthogonal frequency division multiplexing (OFDM) for wide range of applications. Coded-OFDM eliminates interference (ISI) and is robust to radio fading channels impairments. Thus OFDM offers higher data throughput with increased reliability in data transmission. Since the Ultra wideband (UWB) spectrum has the unlicensed nature, all wireless devices sharing the spectrum must coexist. According to Multi Band OFDM Alliance (MBOA), multiband OFDM (MB-OFDM) has the advantageous feature of complying with local regulations by dynamically turning off certain tones or channels in software. But disadvantage is the side-band interferences in UWB caused by MB-OFDM. We propose a soft-spectrum adaptation based Detect and Avoid (DAA) mechanism to suppress the undesired interference. Detection technique is based on power spectrum density estimation and Avoidance mechanism is based on sub carrier nullifying using windowing technique. A type of block Turbo code modulation scheme is employed where the side-band interferences are attenuated quickly. Simulation result of soft-spectrum based DAA technique is shown along with SNR performance comparison between coded and uncoded OFDM.