A Subcarrier-Reference Scheme for Multiuser MISO-OFDMA Systems with Low Probability of Interception

Wenyu LUO  Liang JIN  Yingsong LI  

IEICE TRANSACTIONS on Communications   Vol.E94-B    No.10    pp.2872-2876
Publication Date: 2011/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.2872
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories for Communications
MISO,  OFDMA,  wireless physical-layer security,  low probability of interception,  

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Recently, Li and Xia proposed a physical-layer security design to guarantee a low probability of interception (LPI) for asynchronous cooperative systems without relying on upper-layer data encryption. The proposed scheme utilizes diagonal unitary codes to perform different encoding in the frequency domain over subcarriers within each OFDM block to randomize the transmitted signals. To build on their idea, in this letter, a subcarrier-reference (SR) transmission scheme is proposed with deliberate signal randomization to achieve LPI in multiuser MISO-OFDMA systems. For each user, one of the allocated subcarriers is chosen by the transmitter to send reference signals, and others are chosen to send the user's information symbols. By some deliberate signal randomization, the eavesdropper cannot detect the transmitted symbols, while the authorized users can operate the system successfully without knowledge of the channels by subcarrier-reference demodulation. Extensive simulations are conducted to demonstrate the scheme's effectiveness.