Blind Maximum Ratio Combining using the Constant Modulus Criterion

The use of multiple receivers allows the implementation of diversity combining schemes to increase the SNR trough coherent addition of the input signals. Maximum SNR gain is achieved through maximum ratio combining (MRC). This signal combining scheme requires estimation of both channel coefficient and noise power at each individual receiver which is why it is more difficult to implement than other diversity reception schemes. We show that the Constant Modulus Algorithm (CMA) approximates the MRC solution with no further knowledge of the signal at hand and propose a simple receiver design for satellite communication. Simulations and real-live tests demonstrate near-optimal performance of the design even for multi carrier signals and very low SNR.