Performance comparisons of FDD MIMO and 2.6 GHz TDD massive MIMO: An experimental analysis

Massive multiple-input multiple-output (MIMO) is considered as a breakthrough technology in 5G and beyond 5G systems. Some of its main advantages are providing high spectral efficiency to many users simultaneously in the same time–frequency blocks, strong directive signals towards short-range areas and little interference leaks. However, while massive MIMO exhibits interesting benefits, it is important to investigate its main gains through real deployment scenarios in an operator’s infrastructure. In this paper, we focus on performance comparisons of traditional frequency-division duplex (FDD)-based MIMO and 2.6 GHz Time-division duplex (TDD)-based massive MIMO deployments through experimental analysis under different spectrum and bandwidth in a total of three separate sites and one co-site in an operational infrastructure of an operator in Turkey. We also provide design guidelines and requirements for massive MIMO network deployment and proper acceptance of Key Performance Indicators (KPIs) collection and comparisons criteria. Our experimental results reveal up to 66%, 56% and 23% performance benefits in terms of downlink (DL) cell throughput of 2.6 Ghz TDD-based massive MIMO compared to FDD-based MIMO sites in 800 Mhz (site with approximately same number of User Equipment (UEs) compared with TDD massive MIMO), 1800 Mhz (site with higher number of UEs compared with TDD massive MIMO) and 2600 Mhz (site with lower number of UEs compared with TDD massive MIMO) respectively each having 10 Mhz bandwidth. On the other hand, LTE 1800 Mhz FDD MIMO at 20 Mhz can yield higher user throughput values in comparison to 2.6 GHz TDD-based massive MIMO at 10 Mhz. We also observed that the maximum paired layer reached 14 layers in DL of TDD-based massive MIMO. At the end of the paper, we address the main observations and takeaways of TDD-based massive MIMO deployments.