System design on wide-band 16 QAM/TDMA for land mobile communications

This paper proposes a complexity-reduced decision feedback equalization (DFE) scheme for 16-ary quadrature amplitude modulation (16 QAM) over frequency-selective fading channels. The proposed DFE uses bidirectional equalizing (BDE), and space diversity combining (SDC) to achieve high-spectral-efficiency, high-quality data transmission. To reduce the amount of computation of both BDE and SDC for 16 QAM, this paper proposes a tap gain interpolation scheme, new selection schemes of both the equalizing direction of the BDE and the selection of diversity branch. Using these techniques, a 16 QAM/time division multiple access (TDMA) system with 448 ksymbol/s is designed. The system performance is evaluated by computer simulation, assuming a maximum delay of 13 msec. The results confirm that the proposed system is effective and also simple for high-speed data transmission in land mobile communications