Fourth generation (4G) cellular systems have been nowadays rolled out already in several countries in the world. With networks open to commercial use, one of the key issues is how the quality perceived by the user is influenced by multipath propagation, like it may happen in indoor locations or in any kind of places where electromagnetic waves are partially reflected by walls and other objects. In order to verify this, the signal of a real 4G base station connected to the real radio access network of Telecom Italia has been transmitted into a reverberation chamber where a client was running FTPs using a 4G capable USB dongle as a modem. This paper describe the tests that have been performed and focus on how changes in propagation conditions affected the performances perceived by the user

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A fully operational 4G long-term evolution (LTE) base station is tested in a reverberation chamber to analyze its performance in the presence of a multipath environment, typical of wireless and vehicular communications. Transmission quality parameters are measured ranging from the empty chamber situation (very rich multipath channel) to a very high loading condition to mitigate multipath. In that way, both outdoor and indoor propagation are accounted for. A large attenuation is inserted between the transmitter and the antenna to reduce the signal received by the user to real-life values encountered in both outdoor and indoor environments. In these scenarios, operators may choose to transmit a constant power spectral density throughout all LTE spectrum, or to increase the energy of control channels at the expense of data channels in order to enforce transmission and provide better quality to the user, especially in poor radio conditions. This is called “power boosting,” and its effect is analyzed in this paper

The uplink performance of a real fourth-generation long-term-evolution (LTE) frequency-division multiplexing base station was observed by adopting a reverberation chamber as propagating environment. In the downlink direction, the reception of the LTE signal is limited to mobile station receivers. On the other hand, different reception schemes could be implemented by the base station in the uplink direction. Interference rejection and coordinated multipoint reception criteria are based on spatial diversity and are analyzed in a rich multipath environment. These options could be susceptible to impairments due to the presence of Gaussian noise, also including the more realistic case of a discontinuous noise source. The testing session was carried out under a collaboration program between TIM S.p.A., Nokia, and Università Politecnica delle Marche, and it ended up by introducing envisioned reception solutions of the base station in a live customer’s cellular network

For the first time, the carrier aggregation feature of a live 4G-LTE base station (BS) is checked adopting a reverberation chamber as a propagating environment. To that purpose, two non adjacent bands were chosen: 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 like 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 in order 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, that are of interest to manufacturers and mobile network operators. Results highlight differences between the performance of the two bands as a function of multipath degree and signal strength