An optimum combiner for a smart antenna in an indoor infrastructure wireless local area network

The paper investigates the effect of the variation of the thermal noise level on the performance of an optimum combiner in an arbitrary indoor environment taking into account the multipath characteristics of the radio channel. An indoor infrastructure WLAN scenario with four users communicating with an access point is modeled using a deterministic 2D ray-tracing tool. A smart antenna optimum combiner is then developed for the case when the number of elements of a uniform linear antenna array is equal to the number of users, targeting capacity increase through space division multiple access (SDMA). The effect of the variation of thermal noise level (or SNR per antenna element) on the optimum combiner patterns as well on the obtained signal-to-interference-plus-noise ratio (SINR) values is investigated and compared for the multipath case as well as for the line of sight (LOS) only case.