Estimation of signal to noise ratio in receivers

摘要

This invention concerns the estimation of signal to noise ratio (SNR) at a communications receiver; it may be applicable to a wide range of receivers but is particularly suited for Orthogonal Frequency Division Multiplexing (OFDM) receivers. In particular the invention is a method, a receiver and software for performing the method. The signal to noise ratio (SNR) in the received signals is estimated by directly estimating the power ratio, in the received signal, between the part of the frequency spectrum of the received signal that contains only noise, and the part of the spectrum that contains both signal and noise; and averaging this value over a time interval.

主权项

1. A method for estimating signal-to-noise ratio in an orthogonal frequency division multiplexing radio frequency receiver, the method comprising:
receiving a radio frequency transmitted signal having a signal bandwidth and a noise bandwidth that is wider than the signal bandwidth, the radio frequency transmitted signal comprising multiple sub-carriers, the multiple sub-carriers comprising a plurality of noise only sub-carriers within the noise bandwidth but outside the signal bandwidth and a plurality of signal plus noise sub-carriers within the signal bandwidth; demodulating the radio frequency transmitted signal; sampling the demodulated radio frequency transmitted signal to produce a series of digital samples; transforming a digital signal, based on the series of digital samples, to a frequency domain; in the frequency domain, estimating power of each of the multiple sub-carriers; calculating a noise to noise ratio of noise in the noise only sub-carriers and noise in the signal plus noise sub-carriers, based on the estimated power of each of the noise only sub-carriers and based on the estimated power of each of the signal plus noise sub-carriers; and calculating a signal to noise ratio, based on the noise to noise ratio.