Combined suppression method of ISI and phase noise in TDS-OFDM communication system

A phase noise and time-domain signal technology, applied in the field of ISI and phase noise suppression, can solve the problems of demodulation result deterioration, channel delay, interference estimation and elimination, etc.

CN105610539AInactive Publication Date: 2016-05-25UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2016-05-25
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a combined suppression method of ISI and phase noise in a TDS-OFDM communication system. The method comprises the following steps: carrying out synchronization processing to received signals; extracting a PN sequence; carrying out channel estimation processing; carrying out phase noise primary estimation and suppression processing to the synchronized receivedsignals, thus obtaining first denoised frequency domain signals, first output signals and first denoised time domain signals; obtaining a current time domain sign based on the current first output signals; repeatedly executing ISI elimination processing to the first denoised time domain signals based on the trailing of the PN part and the current time domain sign until reaching a preset end condition; carrying out hard decision and IDFT conversion to the current first output signals; reconstructing time domain transmitting signals; obtaining a second phase noise estimation value based on the time domain transmitting signals; carrying out phase noise elimination processing and ISI elimination processing to the data part of the received signals; and outputting the final result. In application of the method disclosed by the invention, the phase noise interference existing in the present ISI compensation method can be effectively reduced.
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Description

technical field

[0001] The invention belongs to communication technology, in particular to a method for suppressing ISI and phase noise in a TDS-OFDM communication system. Background technique

[0002] Time Domain Synchronous Orthogonal Frequency Division Multiplexing (TDS-OFDM) is a broadband wireless transmission technology adopted by my country's Terrestrial Digital Television Broadcasting Transmission (DTMB) standard (GB20600-2006). Different from the CP-OFDM system based on CP (cyclic prefix) and the ZP-OFDM system based on ZP (zero padding), the TDS-OFDM system does not insert pilot symbols into subcarriers in the frequency domain, but inserts pilot symbols between OFDM symbols in the time domain. The PN sequence is inserted as a guard interval, so the TDS-OFDM system can only do synchronization and channel estimation based on the PN sequence. The DTMB standard defines three frame header modes: frame header mode 1 (PN420), frame header mode 2 (PN595), and frame header...

Examples

Embodiment

[0097] With the number of DFT points N=3780, 64QAM modulation mode, the PN sequence mode used is 420 points PN sequence mode. The phase noise modes are Gaussian color noise model and Wiener phase noise model respectively, and the receiving end performs the above steps 1 to 6 in turn to obtain the final result for demodulation processing The ideal estimation of the channel response of the two multipath channels is as follows: Figure 9 , 10 shown. The receiving end executes steps 2 and 3, and the constellation diagram after channel equalization is as follows Figure 11 shown. After the receiving end executes step 4, the obtained constellation diagram is as follows Figure 12 shown. Figure 13 For the initial (primary) estimate of the phase noise, the comparison between the second phase noise estimate and the actual phase noise shows the difference between the two phase noise estimates. Figure 14 In order to check the channel conditions, the receiving end performs steps ...