Performance evaluation of IR-UWB D-Rake receivers over IEEE 802.15.4a multipath fading channels with Narrow-Band Interference

In this paper, we analyze the performance of a simple receiver architecture for impulse radio (IR) ultra wide band (UWB) systems. The receiver makes use of a differential binary phase shift keying (DBPSK) modulation, and a differential rake (D-Rake) receiver that does not require channel estimation. The performance study is conducted by considering the recently standardized IEEE 802.15.4 a channel model, as well as narrow-band interference (NBI) co-located in the same transmission band of the UWB signal. The analysis will be performed with and without frequency and timing synchronization errors, in order to identify the design constraints of the synchronization unit to guarantee the proper operation of the receiver over realistic propagation environments. The results will show that (i) NBI can significantly worsens the performance of the receiver, (ii) the maximum tolerable frequency offset should be less than 10 KHz for a UWB signal with center frequency equal to 4.5 GHz, and (iii) the maximum tolerable timing offset should be much less than 4.2 ns for a pulse with width of 10 ns (500 MHz of transmission bandwidth at -10 dB with respect to the spectrum peak) and a chip time with duration of 85.3 ns.