Trade-Off Performances in Multiuser MIMO Networks with Quantized CSI Feedback

Multiuser multiple-input multiple-output transmission is identified as one of the promising techniques to vastly increase the transmission rate especially in densely deployed networks where inter-user interference is a major issue. To achieve this, channel state information (CSI) is needed to ensure accurate precoder design at the transmitter in order to effectively mitigate inter-user interference. However, the CSI is usually estimated at the receiver and, after quantization, is sent back to the transmitter. The feedback of quantized CSI incurs additional overhead which then leads to trade-off performances between transmission rate and energy efficiency. We will analyze this trade-off and propose the economy efficiency metric as a potential tool to determine the best operating point when the network is jointly optimized using transmission rate and energy efficiency.