Pulse repetition and cyclic prefix: different transmitting strategies for impulse radio UWB systems

In this paper, we compare the performance of two different communication techniques for impulse radio ultra- wide-band (UWB) systems, which resort to impulsive modulations. These techniques can be applied in a short-range scenario where a central node synchronously communicates with several peripheral nodes. The first one is based on the pulse repetition according to the spreading factor value, whereas the second one relies on the cyclic prefix insertion and the detection in the frequency domain (FD). Since both techniques cause a throughput loss, they have to be compared both in terms of the performance and the maximum data rate that is afforded. An indoor scenario is considered, in which either low- or high-data-rate flows are synchronously transmitted by a central node in the presence of variable system loads. Lastly, alternative detection strategies are also taken into account, which are based on the partial knowledge of the channel parameters. The complexity analysis and simulation results show that the FD approach is effective for high data-rate transmission and in the presence of many data flows, whereas RAKE is more suitable in low-data-rate systems transmitting few data flows.