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Method applicable to measuring channel quality of OFDM system

A channel quality measurement and channel technology, applied in transmission systems, multi-frequency code systems, transmission monitoring, etc., can solve problems such as waste of spectrum resources and reduction of spectrum utilization

Active Publication Date: 2009-10-21
WUHAN HONGXIN TELECOMM TECH CO LTD
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Problems solved by technology

For example, the Rayleigh fading of the channel can cause the energy loss of the signal at most 30dB. If the transmission quality of the signal is to be guaranteed, the modulation and coding method must be set based on the worst channel condition. When the channel quality becomes better, the low-order modulation The coding method causes a great waste of spectrum resources and greatly reduces the utilization of spectrum

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  • Method applicable to measuring channel quality of OFDM system
  • Method applicable to measuring channel quality of OFDM system
  • Method applicable to measuring channel quality of OFDM system

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Embodiment Construction

[0013] The CINR measuring method of the present invention, its principle is that the average power of the pure signal received by the receiver end is divided by the average power of the noise in the channel, because the transmitted signal is always superimposed with noise through the channel transmission, it cannot be directly detected at the receiving end. The power of the pure signal is measured, so the signal power and noise power with superimposed noise must be calculated first, and then the power of the pure signal must be calculated. According to the 802.16e protocol, the uplink signal includes a data signal and a pilot signal, wherein the data signal is mapped to different constellation points according to the modulation mode, and the pilot frequency is mapped to a fixed constellation point. For QPSK modulation, because the power values ​​of each constellation point are the same, the calculation result is the same as the average power of the pilot; but for 16QAM, the dis...

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Abstract

The invention relates to a method applicable to measuring channel quality of an OFDM system, which comprises the following steps that: a DSP chip is used and can quickly and accurately measure two channel parameters of CINR and RSSI of the current channel, wherein the principle comprises that a pilot frequency value after equalization is used for calculating the signal average power received by a receiver, and the power is the summation of an effective signal power and a noise power; guard band subcarriers at two ends of the channel are used for calculating the average value of the noise power; and a receiving signal power detracts the noise power to obtain a pure signal power, a division is performed after the pure signal power and the noise average power are obtained to obtain a CINR value, the average power of the pure signal determined in the processes is an RSSI value and finally the CINR value and the RSSI value are converted into logarithm formats and are reported to an MAC layer.

Description

technical field [0001] The present invention relates to a channel quality measurement method suitable for OFDM system, in particular to a channel quality measurement method suitable for 802.16e base station receiver. Background technique [0002] OFDM is a multi-carrier technology, and its multi-carrier modulation and demodulation is realized by Inverse Discrete Fourier Transform (IDFT) and Discrete Fourier Transform (DFT). In the OFDM system, although the sub-channel spectrum overlaps, due to the orthogonality of the sub-carriers, the signal spectrum has no inter-channel interference at the sub-carrier frequency, so the discrete Fourier transform can be used to achieve demodulation, which improves the channel utilization. . In OFDM systems (such as WiMAX IEEE 802.16e), technologies such as AMC / HARQ / MIMO / AAS can be combined to provide higher network capacity and better network coverage. [0003] Among them, adaptive modulation and coding (AMC, Adaptive modulation and codin...

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Application Information

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IPC IPC(8): H04B17/00H04L27/26H04B17/309
Inventor 李萌
Owner WUHAN HONGXIN TELECOMM TECH CO LTD