Measurement-Based Performance Evaluation of MIMO HSDPA

In this paper, we report on the results of physical-layer multiple-input-multiple-output High-Speed Downlink Packet Access (HSDPA) throughput measurements. These measurements were carried out in two different environments: 1) an alpine valley and 2) a city. In addition to the standard compliant single- and two-transmit-antenna HSDPA schemes, we defined and measured a four-transmit-antenna HSDPA scheme to explore future enhancements of the standard. To analyze the implementation loss, we introduce the so-called achievable mutual information and compare it with the actually measured data throughput. We find that the measured data throughput is far from the optimal, leaving room for future receiver optimizations. Furthermore, we find that the achievable mutual information is far from the channel capacity. Thus, optimizations in the standard could further improve HSDPA performance.