Joint throughput optimized CQI and precoding weight calculation for MIMO HSDPA

In MIMO high speed downlink packet access, the channel adaptation is performed by means of the channel quality indicator (CQI) and the precoding control indicator (PCI). The CQI value is utilized to determine the coding rate and modulation alphabet, as well as the number of spatially multiplexed data streams. The PCI value is associated to a specific precoding vector that is applied to the transmit signal at the basestation. In this work, we derive analytic expressions for the post equalization SINR. These SINR values are then evaluated at the receiver to jointly calculate the CQI and the PCI in order to maximize the data throughput. The SINR expressions are verified not only by simulations but also by outdoor MIMO HSDPA measurements.