Intercarrier interference elimination-based cognitive OFDMA system carrier detection method

A technology of inter-carrier interference and carrier detection, applied in transmission systems, electrical components, etc., can solve problems such as active use of interference, and achieve good inter-carrier interference, low computational complexity, and high detection probability.

Active Publication Date: 2011-01-12
ZHEJIANG UNIV
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

This type of method is mainly designed for unknown interference, so it does not actively use the characteristics of interference

Method used

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  • Intercarrier interference elimination-based cognitive OFDMA system carrier detection method
  • Intercarrier interference elimination-based cognitive OFDMA system carrier detection method
  • Intercarrier interference elimination-based cognitive OFDMA system carrier detection method

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Embodiment

[0072] In a cognitive OFDMA system carrier detection method based on inter-carrier interference elimination of the present invention, the cognitive OFDMA system is composed of N=256 carriers, authorized to M=256 primary users, and each primary user uses 1 carrier . The carrier status of authorized users is a randomly generated 256-length vector composed of 0 and 1, where 0 indicates that the authorized user does not occupy the carrier, 1 indicates that the authorized user occupies the carrier, and the number of 0 and 1 obeys (0.5, 0.5) geometric distribution. The authorized user determines the energy of the transmitted data according to the energy of the noise and the signal-to-noise ratio, and the data adopts BPSK modulation. The carrier frequency offset value of the authorized user obeys [-ε m , ε m ] within the uniform distribution, ε m is the maximum carrier frequency offset, and the two cases of 0.125 and 0.25 are respectively taken for comparison. The set false alarm...

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PUM

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Abstract

The invention discloses an intercarrier interference elimination-based cognitive OFDMA system carrier detection method. The method comprises the following steps of: pre-judging all carriers of which the states are not judged by using a high-conservation threshold lambda H and a low-conservation threshold lambda L by a cognitive user; starting an intercarrier interference elimination algorithm forthe carriers of which the states are not judged; determining whether to remove interfering energy from the currently detected carrier energy according to the adjacent carrier state and whether to judge the currently detected carrier state by using a threshold lambda 1; updating the high-conservation threshold lambda H and the low-conservation threshold lambda L according to a set of the carriers of which the states are not judged; and continuously repeating the steps till the states of all carriers are judged. The method overcomes the disadvantage of high false alarm probability because the conventional energy detector cannot identify intercarrier interference and master user signals, and has the advantages of low computational complexity, capacity of resisting the intercarrier interference well, and high detection probability and low false alarm probability under the condition of larger carrier frequency deviation.

Description

technical field [0001] The invention relates to the field of wireless communication, in particular to a carrier detection method of a cognitive OFDMA system based on inter-carrier interference elimination. Background technique [0002] Cognitive radio technology is a key technology to solve the current shortage of spectrum resources and low spectrum utilization. By reliably sensing the spectrum environment and detecting the active state of the primary user, it allows unlicensed users to dynamically utilize available spectrum resources without causing harmful interference to licensed users during the entire communication process. Orthogonal Frequency Division Multiple Access (OFDMA) technology is currently recognized as a transmission technology that is easy to implement spectrum resource control. OFDMA technology can flexibly allocate system resources among users through spectrum combination and tailoring, which makes it a good combination with cognitive systems. In the co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/707
Inventor 叶露张朝阳
Owner ZHEJIANG UNIV
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