SC-CFDMA carrier frequency offset iterative elimination method based on code domain reconstruction

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), 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 no...

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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