Baseband FPGA for beamspace MIMO RF antenna at LTE-A communication

As the MIMO processing gets popular in LTE wireless mobile communication, the number of RF chains of base station for MIMO processing gets increased, which results in the increase of cost and the volume of eNodeB base-station. In order to solve this problem, the beamspace MIMO RF Antenna has been proposed. The advantage of Beam-space MIMO RF Antenna is to reduce the RF chain which results in the cost reduction of LTE RF module. For implementing Beam-space MIMO, six-port modulator RF has been proposed with the concept of impedance loading. In order to support impedance loading based on six-port modulator, the LTE IQ baseband signal from LTE modem should be transformed to control the six-port modulator RF chip. This transformation is performed by table mapping at FPGA in this design. The requirement of baseband processing is 300Mbps in 33MHz band which supports 4 streams. The integration system has been designed with LTE modem that supports 4×4 MIMO. The testing of full integration system consists of baseband FPGA, LTE modem and Beam-space MIMO RF Antenna module. LTE signal generator, commercial LTE test platform have been used to validate the design of beamspace MIMO RF baseband system during the test procedure.