Method and device for estimating signal noise ratio

Abstract

This invention discloses a method for estimating S / N ratio including: selecting demodulation signal constellation points with the absolute value of the signal component greater than that of the edge constellation point of the modulation signal to compute noise power utilizing the selected demodulated signal constellation points, computing emission power and the ratio with noise power to get an estimated value of the S / N ratio. This invention also discloses a device estimating S / N ratio including: a constellation scheme mapping unit, a constellation point selection unit, a noise power computation unit, an emission signal power computation unit and S / N ratio computation unit.

Description

technical field [0001] The invention relates to digital communication technology, in particular to a method and device for estimating signal-to-noise ratio. Background technique [0002] A digital communication system includes a transmitter, a receiver, and a channel, figure 1 It is a simple structural block diagram of a digital communication system, in which the transmitting end includes information source, encoding, and constellation mapping, and the receiving end includes constellation mapping, decoding, and sink. The transmitting end encodes the bit stream generated by the information source, maps the constellation map, and transmits it; the signal transmitted by the transmitting end is transmitted to the receiving end through a channel; the receiving end performs constellation map mapping and decoding on the received signal, and then transmits it to the sink. Wherein, encoding usually adopts error-correcting code encoding, and corresponding decoding adopts error-correc...

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Problems solved by technology

[0013] from Figure 4 , Figure 5 and Figure 7 It is easy to see that the constellation points of the demodulated signal are distributed around the constellation points of the modulated signal, or even farther away from the constellation points of the modulated signal, and the constellation points of the demodulated signal are easy to overlap, making it difficult to judge the constellation points of the demodulated signal Which modulation signal constellation point is sent by the constellation point

For example, for Figure 4 Shown are the demodulated signal constellation points near the two coordinate axes, for Figure 7 The demodulated signal constellation point near the demodulated signal constellation point near the two coordinate axes and the demodulated signal constellation point in the middle of the modulated signal constellation point are shown for Figure 5 The shown constellation points of the demodulated signal close to the two coordinate axes and the constellation points of the demodulated signal far away from the constellation points of the modulated signal cannot guarantee the correct determination of the correspondence between the constellation points of the demodulated signal and the constellation points of the modulated signal, thus It will cause the calculation error of the noise power, and further cause the estimation error between the estimated value of SNR and the actual value to be large

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