As fifth generation (5G) networks are starting to become commercial, user expectations in terms of new services become high as well. This signifies that mobile communications service providers need to build robust 5G new services as quickly and cost-efficiently as possible. Many new technologies rely on closed-loop (CL) and multiple input multiple output (MIMO) technologies due to emerging cooperation between nodes in next generation networks. In this paper, we first compare different multiantenna transmission modes namely: transmit diversity, open-loop (OL), and CL MIMO spatial multiplexing strategies to provide mobile network operator (MNO) services in terms of their characteristics, ,limitations and benefits. Later we investigate how launching a large-scale CL MIMO deployment strategy can affect the various key performance indicators (KPIs) of the existing services provided by Mobile Network Operators (MNOs) in real-operational network infrastructure in Turkey. Our practical experimental results indicate that, compared to OL MIMO system, CL MIMO can achieve large performance on a practical setup, where up to 3% improvement in cell average throughput, 9% in user throughput, 6% in spectrum efficiency, and 9% in channel quality indicator (CQI) and modulation coding scheme (MCS) are obtained, while reduction by 25% and 17% on sum delay and initial block error rates (IBLER) are observed.
