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For the first time, the carrier aggregation feature of a live fourth-generation Long-Term Evolution (4G-LTE) base station (BS) is checked, adopting a reverberation chamber as a propagating environment. For this purpose, two nonadjacent bands were chosen, i.e., 800 and 1800 MHz, and alternatively set as primary and secondary cells. The multipath conditions were tuned by adding the absorbing material inside the chamber and ranging from an empty condition with a rich multipath to a real environment such as an indoor scenario. The latter is a very interesting and popular situation as it represents one in which people use mobile phones. The multipath variation effect on the BS performance was accurately verified by introducing power compensation to account for the variation of the chamber quality factor $Q$ due to the insertion of absorbers. A complete over-the-air test was carried out by checking typical transmission quality parameters, which are of interest to manufacturers and mobile network operators. Results highlight the differences between the performance of the two bands as a function of multipath degree and signal strength. [ABSTRACT FROM AUTHOR]

The performance of a MIMO 4 × 4 transmission solution applied to 4th generation LTE FDD technology are evaluated inside a reverberation chamber (RC) to quantify its benefit against the LTE typical MIMO 2 × 2 transmission scheme, in different environment conditions. The implementation of MIMO 4 × 4 in live networks requires the connection of two additional cables between base station transmitters and antennas, and operators face additional costs. Throughput and modulation code scheme allocation are analyzed as a function of the signal to interference-plus-noise ratio (SINR), for both indoor and outdoor environments. Experimental results in a live network are compared to those obtained in the RC of our laboratory. Results highlight that MIMO 4 × 4 is convenient for SINR greater than 10–15 dB. These results can help mobile network operators to evaluate if the expected benefit justifies the additional costs in an operating actual network. [ABSTRACT FROM AUTHOR]