Cooperative communication has been recently applied to LTE networks to enable the coverage extension and enhance the link reliability through distributed spatial diversity. In this paper, the femtorelay cooperates with the macro-base station through the amplify-and-forward protocol to enable the transmission of data from the macro-base station to the mobile station in a real-time indoor environment. This paper aims to improve the error performance of a LTE HetNet by using constellation combiner technique. At the destination end, the constellations from the direct and relay links are selected based on the minimum EVM to achieve improved BER with less computation complexity. The above-mentioned system with novel combining technique has been tested and analyzed in a real-time scenario using wireless open-access research platform (WARP) test bed. © Springer Nature Singapore Pte Ltd. 2017.