Dependence of antenna element-spacing on interference suppression effect of smart antennas on multipath fading - experimental verification in anechoic chamber

摘要

We tested an effectiveness of interference suppression of smart antennas with widely-spaced (0.47-8 wavelengths) array antenna for base station receiver under multipath fading environment in anechoic chamber, where direction of arrival (DOA) and delay time of the multipath were varied. For smart antennas, an MMSL-criterion-based array processor and a cascaded connection of multiple constrained-array-processor and maximum-likelihood sequence-estimation (MLSE) equalizer were implemented and those directional patterns and bit error rates ( BERs) were measured. Measured results show that widely-spaced array antenna provide interference suppression effect but also provide spotty degradation of the effect in according to its spatial correlation pattern specially when DOA-difference between direct and delayed paths is small. In contrary when delay time of delayed paths are same, the dependence of the spatial correlation pattern on the effect of interference suppression decreased, because the array processor extracted direct path and passed the delayed paths and then combined them for the interference suppression.