Iterative carrier synchronizing method and system based on code-by-code iterative detection

Abstract

The invention discloses an iterative carrier synchronizing method based on code-by-code iterative detection. The method comprises the following steps of: reconstructing external information generated during the code-by-code iterative detection of interleave-division multiple-access (IDMA) to acquire a reconstructed signal; performing frequency offset estimation according to a received signal during the current iterative detection of the IDMA and the reconstructed signal acquired during the last iterative detection to acquire a current frequency offset estimated value; and compensating a frequency offset generated during the current iterative detection by using the current frequency offset estimated value. Correspondingly, the invention discloses an orthogonal frequency division multiplexing (OFDM)-IDMA carrier synchronizing system based on the code-by-code iterative detection. By combining a multi-user detection mechanism of the OFDM-IDMA system with a frequency offset signal processing method technology, the estimation and the compensation is performed cyclically through an iteration mode, so that the frequency offset estimation precision is improved and the performance of a link of the system is optimized; therefore, the performance of the system subjected to the carrier frequency offset interference is made to gradually approximate to the performance of the system free of the frequency offset, and the carrier synchronization of the system is realized.

Description

technical field [0001] The invention relates to the communication field, in particular to an OFDM-IDMA iterative carrier synchronization method and system based on chip-by-chip iterative detection. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM, Orthogonal Frequency Division Multiplexing) technology is one of the key technologies for future wireless communication systems, and interleaved multiple access (IDMA, interleave-division multiple-access) is a new type of multiple access technology Has aroused widespread concern of people, the combination of OFDM and IDMA technology constitutes OFDM-IDMA. The OFDM-IDMA scheme replaces the CDMA technology in the OFDM-CDMA scheme with IDMA technology. OFDM-IDMA inherits the technical advantages of OFDM and IDMA technology. Among them, OFDM has high spectral efficiency and anti-intersymbol interference (ISI, internsymbol interference) ), IDMA is a multiple access technology that uses low-rate codes and i...

AI Technical Summary

Problems solved by technology

The existence of carrier frequency offset will reduce the signal amplitude, generate phase distortion and destroy the orthogonality between OFDM subcarriers, causing inter-carrier interference (ICI, inter-carrier interference), resulting in the loss of signal-to-noise ratio and system performance degradation. Therefore, it is of great significance to analyze its carrier frequency offset and find an effective method to overcome carrier frequency offset.

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