A Novel Single-RF Transmitter for Massive MIMO

A novel single-RF MIMO transmitter is presented. It comprises only a single power amplifier and does not require any mixer. The voltage source is a fixed sinusoidal oscillator. For each antenna element, data modulation is performed using adjustable two-port networks that control the currents on the individual elements. It is shown that the proposed transmitter can support arbitrary types of modulation at low signal distortion and that the source can be matched perfectly for a large number of antennas. The power amplifier generates a fixed amount of power. A massive MIMO system with OFDM-modulation can be operated at very high amplifier efficiency. To limit the maximum radiated power, two clipping methods are suggested. It is shown that the total power efficiency of the proposed transmitter in the massive MIMO regime using the proposed clipping techniques is significantly higher than the total power efficiency in classical design of MIMO transmitters. Utilizing the aforementioned advantages of the proposed MIMO transmitter makes massive MIMO systems more realistic in terms of cost and size for future generations of wireless networks.