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Method and system for estimating integer multiples of frequency offsets

An integer frequency offset and estimated value technology, which is applied in the field of integer frequency offset estimation, can solve the problems of carrier frequency offset sensitivity, high hardware implementation complexity, and the traditional method cannot be directly realized, so as to improve the accuracy and stability. , The operation process is fast, and the hardware realizes the simple effect.

Inactive Publication Date: 2011-10-12
SICHUAN PANOVASIC TECH +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, the OFDM system also has an obvious disadvantage: it is sensitive to carrier frequency offset
[0010] Since the traditional method is to multiply the received synchronization symbol with the local training sequence (locally generated frequency domain synchronization symbol) to estimate the integer multiple frequency offset, and the local training sequence cannot be obtained in the CMMB system, so the traditional method cannot be directly implemented. , so in the traditional method, the method of dividing the synchronous symbols before and after is usually used to reduce the error, but this method needs to use division, and the complexity of hardware implementation is relatively high

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  • Method and system for estimating integer multiples of frequency offsets
  • Method and system for estimating integer multiples of frequency offsets
  • Method and system for estimating integer multiples of frequency offsets

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Embodiment 1

[0027] a. Receive all synchronous symbols of each frame (no frame has two synchronous symbols), obtain the relational expression 1 between each synchronous symbol and the frequency-domain synchronous symbol sent (by the first synchronous symbol r of each frame sync (1, n) as an example, the relational expression of the second synchronization symbol can be deduced by analogy): where X sync (1, k) is the frequency domain synchronization symbol, N sync is the number of subcarriers in the first sync symbol, H(k) is the channel function, is the normalized frequency offset, is the carrier wave during modulation.

[0028] In order to ensure robustness in practical applications, the symbol timing deviation and sampling frequency deviation are added to the received synchronous symbol relational formula, and the first synchronous symbol r of each frame is sync (1, n) as an example calculation formula 2 is: where the symbol timing offset is n o , and the normalized sampling fre...

Embodiment 2

[0045] The integer multiple frequency offset estimation system used in Embodiment 1 of the present invention includes a conjugate unit, a storage unit and a decision unit in the system. Wherein the conjugate unit is used to realize z of calculation formula 5 in embodiment 1 sync (1,m+1)z * (1, m) part, storage unit is used for realizing computing formula 5 in embodiment 1 Partly, the conjugation unit includes a conjugation module receiving an input signal and a first multiplication module, a delay module is connected between the conjugation module and the first multiplication module, and the signal passes through the first multiplication module To the storage unit, the storage unit includes a storage module, the storage module includes a 2048-bit dual-port RAM and a 2048-bit dual-port ROM, and the dual-port RAM and dual-port ROM are controlled by the control module in the storage unit. After the signal is stored in the storage module, the peak value is obtained by the secon...

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Abstract

The invention relates to a method and a system for estimating integer multiples of frequency offsets. The method comprises the following steps of: a, receiving all synchronous symbols of each frame, and obtaining a relational expression between each synchronous symbol and a transmitted frequency-domain synchronous symbol; b, performing Fourier demodulation on each received synchronous symbol respectively to obtain a frequency domain of the synchronous symbol; c, performing conjugate multiplication on the adjacent code elements of each received synchronous symbol respectively; and d, obtaining an estimation value of the integer multiples of frequency offsets according to a maximum correlation of a result of the step c and frequency-domain data of a transmitting end after cyclic shifts. According to the method and the system for estimating the integer multiples of frequency offsets, disclosed by the invention, the integer multiples of frequency offsets in a wireless communication, in particular a China mobile multimedia broadcasting (CMMB) system can be correctly estimated, the correctness and the stability of the system are improved, the hardware is easy to realize, and the arithmetic process is fast and convenient.

Description

technical field [0001] The present invention relates to a method and a system for estimating an integer multiple frequency offset, in particular to a method and a system for estimating an integer multiple frequency offset in a CMMB system. Background technique [0002] China Mobile Multimedia Broadcasting, referred to as CMMB (China Mobile Multimedia Broadcasting), is a multimedia broadcasting industry standard with independent intellectual property rights proposed by the State Administration of Radio, Film and Television of China in 2006. The standard uses OFDM (Orthogonal Frequency Division Multiplexing) as the modulation and demodulation technology. OFDM technology has the following outstanding advantages: [0003] 1. High spectrum utilization; [0004] 2. It has a strong ability to resist multipath interference, which can ensure the quality of reception under high-speed mobile state; [0005] 3. The implementation is relatively simple. OFDM modulation and demodulation...

Claims

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Application Information

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IPC IPC(8): H04L27/26
Inventor 谢翔武畅谭太秋李玉柏
Owner SICHUAN PANOVASIC TECH