A high bit rate transmission technique in mobile radio cellular environment

A transmission technique using four-level quadrature amplitude modulation and decision feedback sequence estimation (DFSE) has been studied to find the maximum achievable bit rate in a mobile communication channel. The work was performed to design the radio subsystem for the Universal Mobile Telecommunication System (UMTS) within the RACE 1043 Mobile Project. After a brief description of the technique for a time division multiple access system (TDMA), the author presents simulations on bit error rate (BER) at the receiver output as a function of E_b/N₀ or C/ I. Better performances and shorter TDMA blocks are observed. Performances are further improved by using a prefilter prior to the DFSE which turns the channel impulse response into a minimum phase response