Transmission mode selection in a heterogeneous network using opportunistic beamforming

Abstract

In this paper, we consider a heterogeneous network where the statistics of fading channels between the Base Station (BS) and various users are different. The network can operate either in a single-user mode (i.e. the BS transmits to one user at a time) or in a multi-user mode via opportunistic beamforming. Given the profile of users' fading channel statistics, we are able to derive the exact downlink capacities associated with different modes assuming a 2-Tx BS, as well as determine the optimal mode that maximizes the throughput. The switching point between transmission modes depends on the signal-to-noise ratio (SNR), the distribution of users and the path loss of the fading channel. Simula..