A continuous-time IR-UWB RAKE receiver for coherent symbol detection

The ultra-wide bandwidth released for unlicensed use by FCC a decade ago has initiated significant research efforts. The large ultra-wide bandwidth is attractive not only for increased data transfer speed but may also be exploited for added functionality like high-precision ranging in wireless sensor networks. RAKE based receivers are preferred for ultra-wideband (UWB) technology due to wide bandwidth. However, designing RAKE based correlating receivers remains quite challenging. Correlating receivers are also power consuming due to high-speed DSPs, ADC and matched filter. Timing synchronization is another issue associated with correlating receivers. In this paper a impulse radio ultra-wideband (IR-UWB) RAKE receiver is presented utilizing a continuous-time binary value coding scheme for power-efficiency and coherent symbol detection without the need for synchronization to achieve precise ranging using time-of-flight technique. A working prototype of the IR ranging transceiver which uses the IR-UWB RAKE receiver is presented with measured high-precision ranging towards 1.4 cm.