Multi-standard MIMO radio base station transmitters
This white paper describes the challenges inherent in MIMO (Multiple Input Multiple Output) radio transmitter system design, and focuses on recommendations for implementation. The spatial multiplexing scheme used to implement MIMO relies on the ADC receiver data streams and the DAC transmitter data streams being sample synchronous and phase coherent. Maintaining sample synchronization is typically accomplished using brute force methods—FPGA-based state machines plus complex data converter clock and reset logic at board level. New data converters now embed multiple device synchronization functionality, making the implementation of MIMO transceivers much easier.