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Method and system for producing LTE PRACH (Long Term Evolution Physical Random Access Channel) baseband signal

A baseband signal and frequency domain signal technology, applied in baseband system components, transmission systems, digital transmission systems, etc., can solve the problems of inability to use fast algorithms, low computational efficiency, and high algorithm complexity in prime point DFT, and save IFFT. The effect of buffering and saving size after reverse order

Active Publication Date: 2011-01-05
北京中科晶上科技股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To complete the 139-point DFT, 19,321 complex multiplications and 19,182 complex additions are required. To complete the 4096-point IDFT, if you do not use fast operations, you need to perform 16,777,216 complex multiplications and 16,773,120 complex additions; to complete the 839-point DFT, you need to perform 703,921 complex multiplications, 703,082 Complex number additions, 603,979,776 complex number multiplications and 603,955,200 complex number additions are required to complete 24,576-point IDFT. The algorithm complexity of these two steps is high and the operation efficiency is low. Fast algorithms cannot be used for prime number point DFT

Method used

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  • Method and system for producing LTE PRACH (Long Term Evolution Physical Random Access Channel) baseband signal
  • Method and system for producing LTE PRACH (Long Term Evolution Physical Random Access Channel) baseband signal
  • Method and system for producing LTE PRACH (Long Term Evolution Physical Random Access Channel) baseband signal

Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment approach 1

[0072] Perform the phase value of the DFT sequence of the preamble sequence according to the following formula,

[0073] (u -1 k(k+1)+(1-u -1 )k*2*2 -1 +α+2kC v )% (2N ZC ) / N ZC

[0074] where k=0,...,N ZC -1, 2 -1 Represents the multiplicative inverse factor of 2; u is the root sequence number of the leading sequence, u -1 is the multiplicative inverse factor of u, α is the rotation factor, C v is the cyclic shift value.

Embodiment

[0075] Examples are described below.

[0076] The root sequence number u of the preamble sequence is obtained by calculating the parameters in step S100.

[0077] Look up the multiplicative inverse factor table to get the multiplicative inverse factor u of u -1 . There are two multiplicative inverse factor tables according to preamble format 0-3 or preamble format 4.

[0078] Look up the twiddle factor table with u as the index to get the twiddle factor α. There are two different tables of twiddle factors based on preamble format 0-3 or preamble format 4.

[0079] will u -1 and α and the cyclic shift value C calculated by the parameters in step S100 v Press (u -1 k(k+1)+(1-u -1 )k*2*2 -1 +α+2kC v )% (2N ZC ) / N ZC Perform phase calculations, k=0,...,N ZC -1, 2 -1 Represents the multiplicative inverse factor of 2, and obtains the phase value of the DFT sequence of the preamble sequence, which is sequentially written into the frequency domain signal phase buffer, and...

specific Embodiment approach 2

[0080] Perform the phase value of the DFT sequence of the preamble sequence according to the following formula,

[0081] (u -1 k(k+1)+(1-u -1 )k*2*2 -1 +α+2kC v )% (2N ZC )*N IDFT / N ZC

[0082] where k=0,...,N ZC -1, 2 -1 Represents the multiplicative inverse factor of 2; u is the root sequence number of the leading sequence, u -1 is the multiplicative inverse factor of u, α is the rotation factor, C v is the cyclic shift value, N ZC is the number of prime points for DFT in the preamble format adopted in the LTE protocol, N IDFT It is the high number of points for IDFT in the preamble format used in the LTE protocol.

[0083] The embodiment is the same as the embodiment of the specific embodiment one, except that the phase value is calculated according to the formula

[0084] (u -1 k(k+1)+(1-u -1 )k*2*2 -1 +α+2kC v )% (2N ZC )*N IDFT / N ZC Calculation.

[0085] Step S300, configure the length of the IFFT operation that does not include reverse order to be...

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Abstract

The invention discloses a method and a system for producing an LTE PRACH (Long Term Evolution Physical Random Access Channel) baseband signal. The method comprises the following steps of: (1) calculating parameters required by the production of the LTE PRACH baseband signal according to the provisions of the LTE protocol; (2) calculating phase values of a DFT (Discrete Forurier Transform) sequence of a leader sequence, writing the phase values into a frequency domain phase buffer memory in sequence, and executing the step (3) after writing ZNC phase values; (3) configuring IFFT (Inverse Fast Fourier Transform) operation not containing an inverse order to be NIFFT (Non Inverse Fast Fourier Transform) in length and a groups and performing a times IFFT (Inverse Fast Fourier Transform) operation of an NIFFT (Non Inverse Fast Fourier Transform) point; and (4) reading data from a baseband signal buffer memory, sending circulation prefixes and entire sequence part, and clearing the frequency domain signal phase buffer memory and the baseband signal buffer memory to zero after completion. The invention can reduce the times of complex multiplication and complex addition required by high-point IDFT (Inverse Discrete Fourier Transform) during the production process of the LTE PRACH baseband signal.

Description

technical field [0001] The present invention relates to the communication field, in particular to a method and system for generating LTE PRACH baseband signals. Background technique [0002] In order to actively respond to fierce market competition, at the end of 2004, 3GPP (3rd Generation Partnership Project, 3rd Generation Partnership Project) started the LTE (Long Term Evolution, Long Term Evolution) project of the universal mobile communication system technology. The core technology of the LTE standard is OFDM technology. This communication standard with frequency division orthogonal multiplexing as the main technology already has the characteristics of the fourth-generation communication standard, so LTE technology is also called quasi-4G technology. [0003] In the uplink physical channel of LTE, PRACH (Physical Random Access CHannel, physical random access channel) completes the function of sending random access preamble and baseband signal. According to the LTE physi...

Claims

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Application Information

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IPC IPC(8): H04L1/00H04L25/03H04L25/02
Inventor 王剑何莹寇振涛彭吉生石晶林
Owner 北京中科晶上科技股份有限公司
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