BER Analysis of Cross-QAM Uncoded Space-Time Labeling Diversity with Three Transmit Antennas in Nakagami-m Fading Channels

This paper presents a new cross quadrature amplitude modulation (XQAM) technique for three transmit antennas uncoded space-time labeling diversity (USTLD) over Nakagami-m fading channels. A heuristic algorithm is employed in designing the second and third optimized mapper for 32-XQAM and 128-XQAM. The study exploits an approximate analytical expression to derive bit error rate (BER). The average BER is obtained by applying probability density function and moment generating functions. Monte carlo simulation results show a tight fit with the theoretical approximate analysis in the high signal-to-noise ratio (SNR). The BER performance comparison of XQAM USTLD is carried out based on rate one with the existing two transmit antennas XQAM USTLD for link reliability which shows significant improvement. In addition, frame error rate (FER) performance analysis is carried out for real-world wireless communication where the degradation of error performance due to dropped frames is the same for one or many bit errors within a frame. Finally, XQAM transmission performance evaluation is carried out with rectangular QAM (RQAM), amplitude phase-shift scheme (APSK) and phase-shift scheme (PSK) transmission schemes.