2-D Spatial Smoothing for
Hongyi Wang, K. J. Ray Liu · 1998
The use of two-dimensional spatial smoothing (SS) to increase channel capacity of wiidess communications system is discussed. The necessary and sufficient conditions on array configuration for applying SS to multiple signal classification (MUSIC), and adaptive beamforming algorithms are defined and proved. This array must have an orientational invariance structure with an ambiguity free center array, and the number of subarrays must be larger than or equajl to the size of the largest group of coherent signals. We also studied the cause of ambiguities in a multipath environment. We found the necessary and sufficient conditions for a three-sensor array manifold to be ambiguity free and identified several higher order ambiguity situations. If an array is also central symmetric, the forwardhackward SS (FBSS) can be used to improve the resolution. Finally, we extended our results to the estimation of sigpal parameters via rotational invariance techniques (ESPRIT). All the predicted results are verified by simulations.