A method of evm phase estimation and compensation

A compensation method and phase estimation technology, applied in the multi-frequency code system and other directions, can solve the problems of large randomness of phase deviation, error, affecting the measurement accuracy of EVM, etc., and achieve the effect of improving the measurement accuracy.

Active Publication Date: 2017-02-08
南京软仪测试技术有限公司
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Problems solved by technology

[0005] Existing technical solutions usually only use the corresponding received pilot sequence and known sequence to estimate the phase, and then perform phase compensation on other subcarrier data through various fitting methods, because in the process of EVM measurement , the phase deviation between the subcarriers is very random, so there is a large error in the phase compensation according to the above method, which affects the measurement accuracy of EVM

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  • A method of evm phase estimation and compensation
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  • A method of evm phase estimation and compensation

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[0028] The technical scheme of the present invention will be further described in detail below in conjunction with the accompanying drawings:

[0029] The invention discloses an EVM phase estimation and compensation method, such as figure 1 As shown, first define the following symbols:

[0030] The column vector of the pilot sequence of the k-th OFDM symbol in the frequency domain is:

[0031] The actual received k-th OFDM symbol pilot sequence column vector is expressed as:

[0032] The number of OFDM symbol pilot symbols is: N;

[0033] The number of subcarriers occupied by OFDM symbol data is: L;

[0034] The frequency domain data of the kth OFDM symbol is expressed as:

[0035] s → ( k ) = { s ( k , m ) } ( k = 0,1,2 , . . . , m = 0,1 , . . . , L - 1 ) , Where m is the data subcarrier number.

[0036] Using the OFDM system, in the time domain, after removing the cyclic prefix and FFT transformation, th...

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Abstract

The invention discloses an EVM (Error Vector Magnitude) phase estimating and compensating method which comprises the following steps: in a time domain, adopting an OFDM (Orthogonal Frequency Division Multiplexing) system for converting data from the time domain to a frequency domain through the removal of cyclic prefixes and FFT (Fast Fourier Transform), and estimating a phase in an OFDM symbol according to received pilot frequency bit data and the pilot frequency bit data for the known symbol in the frequency domain; compensating the data in the OFDM symbol according to the estimated phase, thereby acquiring compensated data; adopting a criterion of Euclidean distance quadratic sum being minimal for estimating the position of a star map corresponding to the compensated data, thereby acquiring an estimated data; finally estimating residual phase deviation according to the compensated data and the estimated data, and then compensating the data in the OFDM symbol. The EVM phase estimating and compensating method has the advantages that the operation is simple and the EVM precision can be effectively increased.

Description

Technical field [0001] The present invention relates to the field of wireless communication, in particular to an EVM phase estimation and compensation method. Background technique [0002] EVM represents the vector difference between the ideal error-free reference signal and the actual transmitted signal, which is used to comprehensively measure the modulation quality of the system. In communication systems such as TD and LTE, the frequency band transmission of digital signals is that the baseband signal of the physical layer of the transmitting end is first orthogonally modulated, and then transmitted to the receiving end through the wireless communication channel, and then the original is restored after corresponding demodulation at the receiving end. Baseband signal. In this process, the modulation error generated by the modulator, the quality of the radio frequency device and the phase-locked loop noise, thermal noise, and modulator design will cause errors in the modulation...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26
Inventor 郝金光程能杰裴文江金海忠
Owner 南京软仪测试技术有限公司
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