Antenna selection represents an attractive technique that allows to improve performance of wireless systems due to its simplicity and ease of implementation. Antenna selection is able to provide diversity through the use of multiple antennas while keeping low cost and energy consumption by selecting only a subset of the available elements at any given time, hence requiring a smaller number of RF transmitter and receiver chains. This makes it especially suitable for femtocell or small-cell base stations, typically employed by cellular operators to provide indoor radio coverage in customer premises. This article presents an analysis and validation of antenna selection using a LTE-FDD femtocell prototype. The effects on antenna selection performance of different antenna training schedules and channel variation rates are investigated under realistic propagation conditions. It is observed that antenna selection is able to provide substantial gains in terms of channel quality and reliability in interference-limited scenarios, attesting its suitability for large-scale femtocell deployments.

This paper presents experimental evaluation results from a practical LTE-FDD femtocell base-station employing uplink antenna switching. The effects of different antenna training and channel variation rates are analysed under realistic propagation conditions. Significant performance gains in terms of average receiver SINR and error rates are observed for the antenna selection receiver, especially at low mobile terminal speeds typical of indoor femtocell applications. These results demonstrate the effectiveness of simple low-cost antenna selection techniques in practical indoor cellular systems.

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This article presents a distributed antenna system (DAS) architecture for small-cell base stations (BTSs), whereby cooperation between the DAS infrastructure and the BTS allows for an increase in performance compared to conventional systems, while at the same time keeping complexity and cost at low levels. Specifically, the article investigates the improvements in uplink physical layer performance achieved by adding an initial antenna combining step in the DAS system before conventional combining and equalization at the BTS. This initial step can be implemented in a very low-complexity fashion by performing all operations in the time domain and using channel state information calculated at the BTS itself. The article presents this technique in the context of an LTE DAS system. Results from both a software simulator and a custom-made hardware prototype are presented, establishing the feasibility of the proposed architecture.