Long-term evolution (LTE) architecture has recently been enhanced by means of the introduction of multi-antenna systems that make use of multiple input multiple output (MIMO) technology, both at the base transceiver station (eNodeB) and user equipment (UE). MIMO can deploy transmission diversity to achieve more robust transmission in poor propagation conditions and spatial multiplexing to increase throughput and thus LTE performance from an end-user perspective. The most recent version of the standard (Release 10) makes up to eight antennae available for the downlink transmission channel. The paper focuses on the most relevant physical-layer parameters used by LTE to optimise a MIMO system. Performance at different frequencies and bandwidths is investigated over a wide urban area in order to study the network behaviour in actual propagation conditions and to verify whether standard prescriptions are satisfied by a fully operational LTE mobile communication system.