IR-UWB: An high speed digital receiver for very short range transmissions

This paper describes the architecture of a digital signal processor (DSP) for a particular impulse-radio ultra wide band (IR-UWB) radio transceiver. In the way of transmitting in a Wireless Personal Area Network, the system supports communication with a range less than one meter and a theoretical data rate near 1 Gbps. According to those assumptions and according to the band limitation in Europe, the use of several parallel FIR filters is necessary. So in reception, after the amplification stage, the multi- phased Analog to digital converter (ADC) captures the signal at 1.25 GHz for each ADC and so targeting an equivalent frequency equal to 40 GHz. An adjustment of the bus to 64 data samples induces a DSP clock working at 675 MHz. Every 1.6 ns a window of the received and digitalized signal is captured and treated. The signal is a narrow impulse train; each impulse is approximately 1.2 ns wide. The implementation proposed here is a compromising between the speed challenge of the DSP and the type of modulation which is here a digital pulse interval modulation (DPIM). The principle of this architecture will be exposed in this paper including the modulation description, the correlation filter bank and the selective detection that is the main contribution of our solution.