Pilot frequency-based method for performing OFDM residual phase tracking

A phase tracking and phase technology, which is applied in OFDM receiver design and communication field, can solve the problems that the cumulative phase may exceed the range of the arctangent function and the weak ability to suppress noise, etc.

Active Publication Date: 2011-04-20
浙江科睿微电子技术有限公司
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AI Technical Summary

Problems solved by technology

References [4][5][6] use pilots to estimate the residual frequency offset without considering the fact that the accumulated phase may exceed the range of the arctangent function, and the ability to suppress noise is weak

Method used

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  • Pilot frequency-based method for performing OFDM residual phase tracking
  • Pilot frequency-based method for performing OFDM residual phase tracking
  • Pilot frequency-based method for performing OFDM residual phase tracking

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Embodiment Construction

[0068] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments of phase tracking in 802.11n a / g or 802.11n Non-HT and with reference to the accompanying drawings.

[0069] The implementation of the specific algorithm is described below by taking the classical OFDM transmission system IEEE 802.11a wireless local area network system as an example. The 802.11a system includes 64 subcarriers with a subcarrier spacing of 312.5KHz. The 802.11a preamble structure is as follows figure 2 As shown, it includes 10 repeated short training sequences and two repeated long training sequences. Each short training sequence has a length of 16 samples and a duration of 0.8 microseconds. Each long training sequence has a length of 64 samples and a duration of 3.2 microseconds. The first long training sequence is preceded by a guard interval of leng...

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Abstract

The invention discloses a pilot frequency-based method for performing orthogonal frequency division multiplexing (OFDM) residual phase tracking, which comprises the following steps of: configuring a phase compensation mode to be a lag compensation mode or a normal compensation mode according to facts that whether higher phase noise is present and whether a channel is a quick change channel; multiplying l equalized pilot frequencies and (l-1) residual phase complex exponentials, and solving l pilot frequency values with only delta phi phase difference from an actual estimated pilot frequency value; solving phase increment of the current lth OFDM demodulation symbol based on data pilot frequency, and averaging the currently solved phase increment; iteratively averaging l, l-1, l-2, ..., l-N+1 increment phase values; and solving complex exponentials of the phase increments according to the set compensation mode, and multiplying the complex exponentials and the OFDM received data so as to realize tracking compensation of the residual phase. In the method, residual phase tracking can be performed on the basis of pilot frequency of the OFDM in a frequency domain, and the problems that the traditional phase tracking method is easily influenced by noise and the estimated phase exceeds (-pi, pi) are well solved.

Description

technical field [0001] The present invention relates to the technical field of receiver design within OFDM in the field of communications, and in particular to an Orthogonal Frequency Division Multiplexing (OFDM) system suitable for broadband data packet burst transmission applications and performing OFDM residual phase based on pilot frequency method of tracking. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) technology has been widely used in current broadband wireless communication systems and digital broadcasting communication systems because of its excellent anti-multipath capability and high spectrum efficiency. For example, wireless local area network standards WiFi (802.11a / g / n), WiMax (802.16d / e), LTE downlink, digital broadcasting systems DVB, CMMB, etc. all use OFDM technology. [0003] OFDM technology is sensitive to phase offset, and the residual carrier frequency offset, residual sampling frequency offset, phase noise of RF dev...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
Inventor 吴斌周玉梅朱勇旭
Owner 浙江科睿微电子技术有限公司
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