Method for estimating connection quality, diversity combination method, and receiver

A method for combining diversity signals in a digital radio system in which the signals transmitted include bursts consisting of symbols and including a known training sequence, and in which method a received signal is processed by a matched filter, and in which an impulse response and N tap coefficients of the autocorrelation function of the impulse response are computed for the received signal, N being the number of bits in the impulse response, and the received diversity signals are combined by maximal ratio combination before detection, the signals being weighted, before the combination, by a coefficient proportional to signal quality, the method comprising:

• forming a result vector of the length of the training sequence from the symbols of the output signal of the matched filter and the corresponding symbols of the known training sequence, and that the obtained result vector is modified using the autocorrelation tap coefficients,
• computing a mean value and variance for the symbols of the result vector, and
• forming a quantity proportional to signal quality as a quotient of the squared mean value of the result vector and the variance of the result vector.