Transmission of high rate ATM packets over indoor radio channels

The design and performance of a high data rate modem that transmits asynchronous transfer mode (ATM) packets over indoor radio channels is discussed. A discrete Fourier transform (DFT)-based multicarrier modulation technique is used to mitigate intersymbol interface (ISI) caused by a multipath spread of up to 250 ns. A rate one-half channel code is used to combat fading. Computer simulation is performed to investigate the system performance for five different multipath intensity profiles. The system performance is compared using a differentially coherent scheme and a coherent scheme based on channel estimation. The effects of carrier frequency offset and some of the hardware nonlinearities are discussed. Using various channel codes, an signal-to-noise ratio (SNR) of 14-21 dB is required at an average bit error rate (BER) of 10/sup -5/ to transmit a total of 155 Mb/s data over a bandwidth of 280 MHz.