Implementation scheme of 2D directional RAKE receiver

To make full use of the advantage of both RAKE receiver and smart antenna (SA), a novel 2D directional RAKE receiver, is proposed by combining traditional RAKE and smart antenna. For the 2D directional RAKE receiver, we first present the basic principle of SA with a simple physical model, based on which three different implementation schemes of 2D directional RAKE receiver, radio frequency implementation scheme, intermediate frequency implementation scheme and baseband implementation scheme are proposed as well as the study of the expressions of output signals and the analysis of performance. The analysis results show that the scheme of the intermediate frequency has the highest performance cost ratio, by which the multi-path effect can be restrained as well as the perfect directional transmitting/receiving. For baseband implementation scheme, though the beam forming can be realized by using the technique of baseband signal amplitude weighting, the gain of signal interference ratio changes along with the direction of arrival (DOA) because the technique of coherent demodulation is disable in this implementation scheme sometimes, which results in the noise amplification and the fluctuation of performance. The radio frequency implementation scheme performances well, but it is hard to realize in engineering.