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An iterative elimination method of sc-cfdma carrier frequency offset based on code domain reconstruction

A SC-CFDMA, carrier frequency offset technology, applied in carrier adjustment, modulated carrier system, digital transmission system, etc., can solve the problems of indistinguishable, incomplete theoretical system, and short time of SC-CFDMA technology. System implementation, the effect of reducing complexity

Active Publication Date: 2019-02-12
PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the receiving end of the uplink, multi-user carrier frequency offset (Carrier Frequency Offset, CFO) will destroy the orthogonality between SC-CFDMA subcarriers, and introduce ICI (Inter Carrier Interference, inter-carrier interference) and MUI (Multi-User Interference , multi-user interference), which seriously affects the receiving performance and multi-user capability of the system
[0003] Since the SC-CFDMA technology has not been around for a long time, its theoretical system is not perfect at present, and the relevant literature has not conducted a special study on the carrier frequency offset cancellation in the SC-CFDMA system, but only regards the SC-CFDMA signal as a special SC-FDMA signal to process
However, the prerequisite for the existing SC-FDMA carrier frequency offset cancellation method is that multiple users can be distinguished in the frequency domain; while in the SC-CFDMA system, each subcarrier set accommodates several CDMA users, which cannot be distinguished in the frequency domain. distinguish
Therefore, the existing methods cannot be directly applied to carrier frequency offset cancellation in SC-CFDMA systems, and the frequency offset cancellation algorithm must be redesigned according to the characteristics of SC-CFDMA signals

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  • An iterative elimination method of sc-cfdma carrier frequency offset based on code domain reconstruction
  • An iterative elimination method of sc-cfdma carrier frequency offset based on code domain reconstruction
  • An iterative elimination method of sc-cfdma carrier frequency offset based on code domain reconstruction

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Embodiment Construction

[0033] The present invention will be described in detail below with reference to the accompanying drawings and examples.

[0034] 1) System description

[0035] Such as figure 1 As shown, the total number of subcarriers in the SC-CFDMA communication system, that is, the number of FFT points N is 512, the CP length is 20, and the number of subcarriers occupied by each user, that is, the size of the subcarrier set is 64. If the spreading factor is defined as J, then in each SC-CFDMA symbol, the number of modulation symbols actually sent by each user is P=64 / J. If J=1, that is, no spread spectrum, then SC-CFDMA degenerates into a general SC-FDMA system, there is only one user on every 64 subcarriers, and this user sends 64 modulation symbols; if J=64, that is, user data In the 64-fold spread spectrum in the time domain, each user only transmits one modulation symbol on 64 subcarriers, and 64 subcarriers can accommodate up to 64 users.

[0036] 2) Channel model

[0037] Two ki...

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Abstract

The invention provides an SC-CFDMA carrier frequency offset iterative elimination method based on code domain reconstruction to realize joint elimination of the carrier frequency offset of multiple users. The method comprises the following steps: S1, extracting subcarrier sets from the results of N FFTs of a receiver; S2, respectively multiplying the subcarrier sets by frequency offset cyclic deconvolution matrixes of the corresponding users to preliminarily eliminate the influence of frequency offset on the users; S3, restoring the symbol value of each user on the allocated subcarrier through code domain reconstruction; S4, carrying out interference signal reconstruction, multiplying the result in S3 by frequency offset cyclic convolution matrixes of the corresponding users, and recreating the interference items of the frequency offset of each user to the other users; S5, removing all the interference items from the other users from the signals of the users; S6, carrying out subcarrier extraction again, and multiplying the subcarriers by the frequency offset cyclic deconvolution matrixes to complete iterative frequency offset elimination; and S7, carrying out data demodulation on the basis of completing iterative frequency offset elimination.

Description

technical field [0001] The invention belongs to the field of wireless communication, and relates to an SC-CFDMA carrier frequency offset iterative elimination method based on code domain reconstruction. Background technique [0002] SC-CFDMA is a new communication system formed by combining SC-FDMA and CDMA. As an improved SC-FDMA, SC-CFDMA inevitably inherits the weakness of SC-FDMA which is sensitive to synchronization deviation. At the receiving end of the uplink, multi-user carrier frequency offset (Carrier Frequency Offset, CFO) will destroy the orthogonality between SC-CFDMA subcarriers, and introduce ICI (Inter Carrier Interference, inter-carrier interference) and MUI (Multi-User Interference , multi-user interference), seriously affecting the receiving performance and multi-user capability of the system. [0003] Since the SC-CFDMA technology has not been around for a long time, its theoretical system is not perfect at present, and the relevant literature has not c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/00
CPCH04L27/0014H04L2027/0038
Inventor 丁丹廖育荣姜明勇倪淑燕李云涛柴黎杨君
Owner PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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