Code-Division Multiplexing based Hardware Reduction for a Digital Beamforming Transmitter Array

This paper proposes a new system architecture to reduce the hardware cost for a digital beamforming (DBF) transmitter array. In a conventional DBF transmitter array, each signal channel requires a digitalto-analog converter (DAC) to convert the digital signal to the analog signal, so that the cost and power consumption for such systems are often prohibitively high as the array size increases. In the proposed DBF transmitter array system, code-division multiplexing (CDM) technique is used to combine digital signals from different channels, and thus the required number of DACs can be significantly reduced. The combined signal is separated by demodulation with the corresponding code sequences for each channel after the DAC. Principle of CDM for hardware reduction in a DBF array system is analyzed. A system-level simulation is performed in Simulink to verify the performance of the proposed system. Simulation results show that the beamforming accuracy and signal quality can be maintained with a reduced number of DACs.