Performance of hard decision detection for impulse radio

Impulse radio (IR) is an ultra-wide bandwidth, time-hopping, code division multiple access (CDMA) technology that possesses unique characteristics that make it a promising candidate for future tactical military radio networks. In this paper, we present an analysis of the bit error performance of IR using hard decision detection and soft decision detection techniques in an environment with dense multiple access interference and large near-far ratios, including severe interference from several local transmitters and a large number of distant interferers and thermal noise. The results show that hard decision detection performs better than soft decision detection in the presence of several large interferers. We discuss the tradeoffs between hard decision detection and soft decision detection, and we also compare the performance of hard decision detection and soft decision detection with blanking. In the soft decision detection with blanking scheme, the input signal is blanked during any interval when an interfering pulse overlaps the desired pulse. This blanking scheme requires knowledge of the time-hopping pattern of the interfering users and a corresponding increase in the complexity needed to achieve synchronization. Our analysis shows that the performance of the hard decision detection receiver is nearly equivalent to the performance of the soft decision detection receiver with blanking without an increase in complexity.