Fixed point Dual Circular 32-QAM performance for Wireless USB

The creation of Ultra-Wideband (UWB) radio platform has allowed the development of high bit-rate Wireless-USB offering High Definition video streaming. Quadrature Phase Shift Keying (QPSK) and Dual Carrier Modulation (DCM) are the current modulation schemes used for Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the ECMA-368 defined UWB radio platform. ECMA-368 offers up to 480 Mb/s instantaneous bit rate to the Medium Access Control (MAC) layer to enable the high-rate transmission, but depending on radio channel conditions dropped packets unfortunately result in a lower throughput. This paper presents a higher data rate modulation scheme that fits within the configuration of the current standard to increase the system throughput by achieving 600 Mb/s (reliable to 3 meters) thus maintaining the high rate USB throughput even with a moderate level of dropped packets. The modulation system is termed Dual Circular 32-QAM (DC 32-QAM). The system performance for fixed point DC 32-QAM modulation is simulated in realistic multipath environments.