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Method for fast realization of soft-demodulation and soft-modulation in high-order quadrature amplitude modulation

A technology of quadrature amplitude modulation and implementation method, which is applied in the direction of multi-carrier system, etc., and can solve the problems of high complexity

Active Publication Date: 2005-09-07
HUAWEI TECH CO LTD
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Problems solved by technology

But when the modulation order is too high, the complexity of reconstructing the signal mean variance from the bit likelihood ratio is still relatively high

Method used

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  • Method for fast realization of soft-demodulation and soft-modulation in high-order quadrature amplitude modulation
  • Method for fast realization of soft-demodulation and soft-modulation in high-order quadrature amplitude modulation
  • Method for fast realization of soft-demodulation and soft-modulation in high-order quadrature amplitude modulation

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Embodiment Construction

[0066] The implementation method of soft demodulation adopts the fast look-up table implementation method, which includes the following steps:

[0067] Step 1), according to formula [6], calculate first, generate and save the lookup table used for soft demodulation according to a certain number of quantization bits.

[0068] Step 2), normalize the received signal and the noise variance according to the channel corresponding coefficient, such as figure 1 As shown, the received signal r is first normalized by the channel gain coefficient ρ, and the normalized received signal r′=r / ρ and the reciprocal ρ of the normalized noise variance are obtained 2 / σ 2 .

[0069] Step 3), quantize the normalized received signal, and the quantization can use uniform quantization or non-uniform quantization.

[0070] Step 4), the signal q (r ') after quantization is carried out table look-up, the value obtained after table look-up is multiplied by the reciprocal of the noise variance of norma...

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Abstract

The invention discloses a method for fast implementing soft demodulation and soft modulation in the high-order quadrature amplitude modulation (QAM), relating to a mobile communication method of high speed data transmission adopting the QAM. And its soft demodulation implementing method adopts the fast table looking-up method, containing the below steps: firstly generating and storing the look-up table used by the soft demodulation, normalizing receipt signal and noise variance according to channel corresponding coefficients, quantizing the normalized receipt signal and making table look-up or table look-up combined with interpolation for the quantized signal, multiplying the value obtained after the table look-up by the normalized noise variance to obtain the needed bit likehood ratio; the soft modulating method includes the following steps: making converting calculation on the bit likehood ratio and according to the linear relation between character and bit mapped by natural QAM, and according to mean value and variance of the bit, calculating the mean value and variance of the character.

Description

technical field [0001] The present invention relates to a broadband mobile communication system for transmitting high-speed data by using multiple transmitting / receiving antennas, and more particularly to a mobile communication method for high-speed data transmission using high-order QAM (Quadrature Amplitude Modulation) modulation. Background technique [0002] Future wireless communication systems not only require high-speed data transmission, but also require high spectrum utilization efficiency. High-order modulation is an effective means for wireless communication systems to achieve high spectrum utilization. Powerful error control codes such as Turbo codes and LDPC codes can greatly enhance the anti-interference ability of communication systems, so bit-interleaving code modulation has become an important baseband processing method in wireless communication systems. In this type of system, the decoder needs the bit-likelihood ratios from the detector (demodulator), esp...

Claims

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Application Information

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IPC IPC(8): H04L27/32
Inventor 高西奇尤肖虎王闻今
Owner HUAWEI TECH CO LTD
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