Interference characteristics between 2.4-GHz-band middle-speed wireless LANs using direct sequence and frequency hopping

Middle-speed (1-to-2-Mbit/sec) 2.4-GHz-band wireless LAN systems are widely used throughout the world. As they occupy the same frequency range, electromagnetic interference will occur between them. We investigated the interference characteristics between wireless LAN systems that use direct sequence (DS) and frequency hopping (FH). Experimental results showed that varying the modulation parameters changed the interference characteristics of the throughputs of wireless LAN systems. Calculated throughput characteristics for the interference agreed with experimental results. Calculating of the DS and FH system performance when E/sub b//N/sub 0/=20 dB showed that the D/U ratio required for the FH system was smaller than those required for the DS systems. However, when the D/U ratio was above 8 dB, the throughputs of the DS systems were higher than that of those FH system. These results clarified the interference characteristics, and will be useful in the prediction of communications performance in environments where DS and FH systems are intermixed.