Efficient Hybrid Modulation with Phase-Directed Pulse Position Estimation for UWB-IR Systems

This paper proposes an efficient hybrid modulation scheme for a mixed phase-shift keying and pulse-position modulation (PSK/PPM) for heterogeneous networks employing ultra-wideband impulse radio (UWB-IR). The proposed scheme can support both coherent and noncoherent reception and is compatible with the IEEE 802.15.4a standard. Conventional hybrid modulation schemes for heterogeneous networks are generally constructed with a super-orthogonal coding (SOC) technique with which coherent receivers can get an additional performance improvement by encoding the phase bits. However, with the proposed modulation scheme, a coherent receiver can achieve a performance improvement by displaying its best capability on phase detection through a simple waveform mapping scheme. The proposed scheme requires no extra hardware or power consumption for performance improvement in coherent receivers. Simulations show that the BER of the proposed scheme in a coherent receiver is increased by 2.7dB over the hybrid modulation with no combined phase coding and also comparable to the SOC-combined modulation scheme employed in the IEEEE 802.15.4a. The error performance of the proposed scheme is analyzed, and the numerical results are presented in this paper.