Antenna Configurations for 4x4 MIMO in LTE - Field Measurements

The 3GPP LTE standard for mobile broadband includes multi-antenna transmission modes that improve performance, both in terms of coverage, spectral efficiency and peak throughput. The antenna system design, both at the eNB and at the UE is critical to a well performing system; it should be designed with the intended performance profile in mind. Field trials were performed in order to investigate the relative performance of several four and two transmit antenna setups in an LTE system. In general, multi-antenna technology gave substantial performance gains over single antenna transmission. A closely spaced co-polarized configuration gave the best performance for users with poor channel quality while dual-polarized and well-spaced antenna configurations gave better performance for users with good channel quality. The trial also shows that UE antenna polarization is an important parameter that must be kept in mind when designing the eNB antenna system.