Recently clear market needs are observed to further boost the downlink peak data rate to 1.2Gbps and 1.6Gbps, which requires support of 8 layers on a single carrier to increase the spectrum efficiency. To achieve that goal, utilization of 8 receiving antenna (8Rx) in downlink is a must. Correspondingly, the new UE DL category 18 and 19 were introduced in TS 36.306
with square brackets. And RAN4 is expected to specify the new RF, RRM and demodulation performance requirements for them.
Many benefits can be achieved by 8Rx UE. It can significantly improve the downlink throughput for a single user across the cell, and also enhance the coverage for the cell edge users. Considering that 256QAM and even higher order modulation scheme was and will be introduced, 8Rx would be one of the efficient and robust ways to make the use of them feasible in the practical operating SINR range. Besides, 8Rx UE with IRC has the capability of cancelling more inter-cell interferers.
To study the performance benefits of 8Rx, a new study item " Study on LTE DL 8Rx antenna ports " was approved at RAN #76, and the current document summarizes the study done under this study item.