Energy-Based Equalization of A Non-Coherent On-Off Keying UWB System for Data Rate Enhancement

Non-coherent ultra-wideband (UWB) impulse radio systems are easier to implement than their coherent counterparts, because the strict synchronization requirements are relaxed. The trade-off for simplicity is a loss in performance. The pulse-repetition interval (PRI) for non-coherent UWB schemes is limited by the maximum channel delay, to avoid inter-symbol interference (ISI). This affects the maximum data rate achievable. For a coherent system, ISI can be mitigated by equalization, which is generally not applicable for non-coherent methods. In a non-coherent energy detector for instance, the square-law device at the receiver destroys the multipath phase information, making complete ISI mitigation impossible. This paper proposes the use of zero-forcing equalizer based on the partial channel information derived from the energy received over an integration time for on-off keying (OOK) transmission. The proposed scheme does not suffer from noise enhancement because the multipaths do not fade simultaneously. The performance of the proposed system is extensively simulated and the results are discussed in detail.