Inter-Symbol Interference Reduction in UWB Communications by RAKE and Multiple Antenna Combining

Inhalt:
This paper deals with the possibility of reducing Inter-Symbol Interferences (ISI) in Ultra Wide Band (UWB) communications. For this purpose, RAKE receivers and/or Multi Element Antennas (MEA) at the receiver side are introduced. A Signal to Interference Ratio (SIR) is defined in order to evaluate the importance of ISI. It appears that a SIR gain of 3 dB is obtained by doubling the number of elements in the MEA with the condition that the antennas are sufficiently spaced. Directional angular scenarios are less favourable than omni-directional scenarios. Alternatively, the use of RAKE combining can enhance the SIR, up to a certain limit. The maximal SIR gain depends on the channel density and on the data rate. If both RAKE receivers and MEA are employed, the resulting SIR gain equals the sum of SIR gains of each method.