Compatibility criteria for digital radio systems in nonlinear channels

The electromagnetical compatibility (EMC) criteria for radio systems engineering are discussed with multiple channel reuse for frequency, time and code division multiple access (FDMA, TDMA and CDMA) schemes in a mobile environment. The BER is usually used as a measure of digital signals transmission quality. In nonlinear radio-channels with multipath propagation, the dynamic BER is used to evaluate the communication range R, which is the basic parameter of cellular radio. The intrasystem interference level is a parameter, which mostly limits the channel reuse in cellular systems. To fulfil the EMC condition, the interference influence should be optimized. We discuss the structural solutions based on the co-channel reuse distance as well as the signals orthogonality, especially for direct sequence CDMA systems