Multiple Transmit Antennas with Limited Feedback in Device-to-Device Networks
Jeonghun Park and Robert W. Heath, Jr.
Submitted to IEEE Wireless Communications Letters, Nov. 2015.
We consider an overlay device-to-device network, where each multiple-antenna transmitter sends data to a desig- nated single-antenna receiver by using maximum ratio trans- mission based on limited feedback. The transmitter locations are modeled by a homogeneous Poisson point process. We obtain a lower bound on the optimum number of feedback bits that maximizes net spectral efficiency, capturing the overall system gain of using limited feedback. Our main finding is that the optimum number of feedback bits scales linearly with the number of transmit antennas and logarithmically with the channel coherence time and the inverse of the node density.