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Method for decreasing peak average power rate

A peak-to-average power ratio and signal technology, which is applied in the field of orthogonal code division multiplexing or orthogonal frequency division multiplexing signals, and can solve problems such as multiple maximum values

Inactive Publication Date: 2009-01-14
ALCATEL LUCENT SAS
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  • Abstract
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  • Application Information

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Problems solved by technology

[0004] A common disadvantage of prior art soft clipping methods is that subtracting the reference function from the overscaled signal portion results in multiple maxima

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  • Method for decreasing peak average power rate
  • Method for decreasing peak average power rate

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Embodiment Construction

[0022] Figure 4 The peak value 400 of the signal to be transmitted in the time domain is shown. Peak 400 is a scale signal and is above the clipping threshold.

[0023] Peak 400 is decomposed into Gaussian functions 500 , 502 and 504 . The number of Gaussian functions used for the decomposition should be chosen in proportion to the duration of the peak 400 . To achieve soft clipping, a benchmark function such as figure 2 function shown.

[0024] The position of the subtracted base function is determined by the position of the elementary function obtained by peak 400 decomposition. The scale of the base function at these locations is determined by the amplitude of the corresponding elementary function. In this way, it only takes one recursion or less to bring the peak 400 to the clipping threshold.

[0025] More generally, the peak value P of the signal to be transmitted above the clipping threshold is computed as the cumulative sum of the elementary function f:

[002...

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Abstract

The present invention relates to a method of reducing a peak-to-average power ratio of a signal to be transmitted, the method comprising the steps of: detecting a portion of the signal being above a clipping threshold level, decomposing the portion of the signal into a number of functions, the number of functions being proportional to a duration of the portion of the signal, performing the number of soft-clippings on the signal by means of a reference function, the positions of the soft-clippings being given by the positions of the functions and the respective scalings of the reference function being determined by the amplitudes of the functions. <IMAGE>

Description

technical field [0001] The present invention relates generally to systems and methods for transmitting digital signals, and more particularly, to clipping techniques that reduce the peak-to-average power ratio of multicarrier multiplexed signals, such as Orthogonal Code Division Multiplexing (OCDM) or Orthogonal Code Division Multiplexing (OCDM) or Orthogonal Code Division Multiplexing (OCDM) Frequency Division Multiplexing (OFDM) signals. Background technique [0002] A large peak-to-average power ratio reduces the efficiency of the transmission power amplifier. The problem is particularly acute for multi-carrier multiplexed signals, such as OCDM and OFDM signals, because the maximum possible peak power of these signals is much larger than the average transmit power. [0003] US Patent No. 6175551 shows one method of reducing the peak-to-average power ratio by soft clipping. Soft clipping means that the proportional reference functions are subtracted from the sampled sign...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/00H04L27/26
CPCH04L27/2624
Inventor 彼得·耶内克托马斯·勒韦尔
Owner ALCATEL LUCENT SAS