Implementation and measurement of single user MIMO testbed for TD-LTE-A downlink channels

This paper, design and utilize the implementation of 8 × 2 outdoor single-user multiple-input, multiple-output (SU-MIMO) systems for time division duplex LTE-A channels at 2.680 GHz to 2.690 GHz. With this purpose, there is a need for accurate and actual radio propagation model at these bands where around the Shanghai Jiao Tong University (SJTU) campus network. In that SU-MIMO testbed, both the transmitter and the receiver communications are made by employing eight (four pairs of cross polarization) antennas in the transmitter side and 2 at the receiver for real time network. Measurements show the experimental characteristics of the future Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH), sensitive to absolute power levels that may not be enough to support a large number of UEs in a cell. We also show the weakness of the current cellular network that is to reach an accurate synchronization such as Coarse Timing Synchronization (CTS) between the receive symbols. This CTS defect can lead to the severe performance degradation and issue for MIMO wireless systems.