Demodulation method and device for unipolar modulated signal

Abstract

The demodulation method of unipolar modulated signal includes first obtaining the unipolar demodulation signal of paging indication channel (PICH) by utilizing the information of common pilot channel (CPICH); estimating the fading period of the propagation channel with Doppler frequency in the same time; obtaining CPICH reference level based on the fading period; determining the PICH hard judgment threshold with the power bias of CPICH and PICH and the reference level; and finally judging the unipolar demodulation signal with the threshold to obtain demodulated unipolar signal. The said method can overcome the effect of fading on the statistical threshold precision of unipolar modulation signal to raise the demodulation performance and reliability of unipolar modulation signal. The present invention also provides one kind of unipolar modulation signal demodulating device.

Description

technical field [0001] The invention relates to a signal processing method in a communication system, especially a signal demodulation method and device. Background technique [0002] In the Wideband Code Division Multiple Access (WCDMA) system, for downlink common channels such as the Paging Indicator Channel (PICH), the biggest feature of this type of channel is that most of its paging indicator signals are 0, and only a few Its paging indication signal is 1. Since the signal is modulated by the method of bipolar modulation signal in the current system, the paging indication only instructs the relevant terminal to read the accompanying S-CCPCH (auxiliary common control physical channel) signal when it is 1, or only at this time The paging indication is meaningful, so under this modulation method, the channel is often transmitting useless information 0. That is, many times the channel is transmitting useless information. [0003] In order to save the downlink transmissio...

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Problems solved by technology

[0005] As an alternative to the above method, if a certain indicator of the reference channel, such as SIR or the required signal level, is firstly obtained, and then the method of subtracting the power offset between the target channel and the reference channel is used to demodulate the unipolar modulation signal, since the unipolar modulation signal fluctuates, and hard judgment needs to be made for each symbol, if the above method is directly used, the signal needs to be transmitted frequently between the two channels, and because the reference channel solution Each symbol that is tuned out is greatly disturbed by noise, which will reduce the accuracy of the threshold decision, thus affecting the accuracy of the entire demodulation result

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