A study of the effect of microwave oven interference on time performance of digital radio communications systems

With increasing use of wireless communication systems and electronic equipment using high-frequency devices, a poor electromagnetic environment for wireless communication systems is expected. This payer discusses the microwave oven, which is a widely used ISM apparatus. The effect of the interference waves generated by a microwave oven on the bit error characteristics of various wireless communication systems (PDC, PHS ISM band wireless LAN) is studied. First, based on the measured interference waves generated from various microwave ovens, the statistical nature of the interference waves is discussed. It is found that a high level interference wave with periodicity is generated from microwave ovens and that the level and duration of the interference wave increase as the oscillation frequency of the magnetron is approached. Next, the bit error rates of pi/4 shift QDPSK and DS/CDMA systems are simulated on a computer. It is found that the bit error rate is changed substantially by the effect of the interference wave. Further, fur the case where the TDMA system is used as a multiple access system, a channel assignment method based on the periodicity of the interference wave is proposed. It is clear that the bit error rare can be improved significantly bq using the proposed channel assignment method. (C) 1997 Scripta Technica, Inc.