Hybrid PPM-BPSK for Transmitted Reference Pulse Cluster Systems in UWB and 60-GHz Channels

Transmitted reference pulse cluster (TRPC) is an impulse radio technology developed for ultrawideband (UWB) communications that achieves superior performance among noncoherent (NC) schemes with low complexity. It employs binary phase-shift keying (BPSK) in the pulse cluster to carry information. In this letter, a hybrid pulse position modulation (PPM) and BPSK is introduced into the TRPC to improve energy efficiency and/or increase data rate. Two types of bit-to-pulse cluster mapping are proposed, one of which is termed Gray PPM-BPSK. It is shown by analysis and simulation that, compared with the original BPSK-TRPC, the new Gray PPM-BPSK-based TRPC not only increases the data rate by a factor of 2 but also achieves 1.5-3-dB coding gain in the BER performance. The performance improvement of the proposed hybrid schemes over BPSK-TRPC and NC PPM is demonstrated over both 3-10-GHz UWB and 60-GHz millimeter-wave channels, making it a promising signaling candidate for these frequency bands.