Experimental characterization of a direct-sequence spread-spectrum optical wireless system based on pulse-conformation techniques for in-house communications

In this paper, the design and experimental testing of a direct-sequence spread spectrum (DSSS) system for wireless infrared LAN is presented. This method improves the wireless IR communications performances against multipath propagation and narrowband interference. We have implemented a IR-DSSS prototype with 100 MHz code frequency and 6 Mbps bit rate. We have also studied the effects of both Gaussian and sinusoidal signal conformation over wireless optical DSSS systems. These results show that these techniques reduce the adjacent-channel interference without loss of process gain or substantial reductions of BER vs. S/N performances. We also present some results about a simplified synchronization structure to be used on reduced-cost domestic equipment. These systems are suitable for different applications at low and medium rates, especially for in-house.