16 QAM digital modem for indoor wireless packet communications

This paper describes a 16-ary quadrature amplitude modulation (16 QAM) digital modem for 4 Mbps wireless LANs on the 2.4-GHz Industrial, Scientific, and Medical (ISM) band and the results of the simulations of frame error characteristics. Because the demand for land mobile communications is increasing rapidly, multi-level modulations have recently been drawing much attention. Although some field experiments using 16 QAM and time division multiple access (TDMA) have been made and some applications proposed, we have concluded that 16 QAM is suitable to be used for indoor communications because the delay spreads and the maximum Doppler frequencies in indoor environments are generally smaller than those in the outdoor environments. Consequently, we have designed this modem for wireless LANs on the ISM band which is one of the applications of indoor communications. From the simulations, we found that the frame error rate vs. signal to noise ratio curve of this modem was about 3 dB degraded compared with the theoretical one.