Modified pulse repetition coding boosting energy detector performance in low data rate systems

We consider ultra-wideband impulse radio (UWB-IR) low data rate (LDR) applications where a more complex cluster head (CH) communicates with many basic sensors nodes (SN). At receiver side, noncoherent energy detectors (ED) operating at low sampling clock, i.e., below 300 kHz, are focused. Drawback is that EDs suffer from significant performance losses with respect to coherent receivers. Pulse repetition coding (PRC) is a known solution to increase receiver performance at the expense of more transmit power. But in LDR systems known PRC is very inefficient due to the low receiver sampling clock. Boosting transmit power is not possible due to Federal Communications Commission´s (FCC) power constraints. Hence, we present a modified PRC scheme solving this problem. Modified repetition coded binary pulse position modulation (MPRC-BPPM) fully exploits FCC power constraints and for EDs of fixed integration duration is optimal with respect to bit error rate (BER). Furthermore, MPRC-BPPM combined with ED outperforms SRAKE receivers at the expense of more transmit power and makes ED´s performance robust against strong channel delay spread variations.