Diversity combining

Diversity combining is the technique applied to combine the multiple received signals of a diversity reception device into a single improved signal.

Various diversity combining techniques can be distinguished: 

• Selection combining: Of the N received signals, the strongest signal is selected
• Switched combining: The receiver switches to another signal when current signal drops below a predefined threshold. This is a less efficient technique than selection combining.
• Equal gain combining: All the received signals are summed coherently.
• Maximal-ratio combining is often used in large phased array systems: The received signals are weighted with respect to their SNR and then summed.