Experimental analysis of network-aided interference-aware receiver for LTE MU-MIMO

Multiuser (MU) MIMO is a promising technique to significantly increase the cell capacity in LTE systems. However, users scheduled for MU-MIMO may still experience strong MU interference if the channel state information at the base station is outdated or in small cells with a limited number of users available. Interference-aware (IA) receivers exploit information about the interfering data stream, such as the modulation order, in the decoding process, resulting in a significant performance gain over interference un-aware (IU) receivers while maintaining a moderate complexity. In this paper we study a network-aided interference-aware (NA-IA) receiver that receives the interfering modulation order through network signaling and an IA receiver that uses heuristics to determine the interfering modulation order. We use the real-time OpenAirInterface LTE testbed to experimentally evaluate the performance of IA and IU receivers in terms of throughput under different levels of MU interference. The measurement results show that the NA-IA receiver achieves significantly higher data rates compared to the IA receiver, especially when MU interference is strong. The IU receiver on the other hand requires very low levels of MU-interference to achieve a performance comparable to the IA receivers.