Abstract
We propose a novel transmission scheme for the parallel Gaussian broadcast channel with confidential messages (BCCM). In this model, The source node wishes to transmit a confidential message to each user over N independent sub-channels, where each sub-channel is degraded for one user than others. Our objective is to design a secure transmission technique that maximizes the sum secrecy rate under an average power constraint. The most common technique to tackle this problem in practice is orthogonal frequency division multiplexing (OFDM). Nevertheless, the OFDM-based BCCM suffers from excessive bandwidth utilization due to the sub-carrier orthogonality requirement. We propose a sparse non-orthogonal frequency-division Multiplexing (SNOFDM) transmission scheme. In SNOFDM, sub-carriers are generated by first selecting a subset of orthogonal sub-channels to reduce spectral resources. Then, the selected sub-channels are multiplexed in time to generate non-orthogonal sub-carriers. This, in effect increases, the spectral efficiency compared to OFDM. To overcome the interference introduced due to the non-orthogonality of sub-carriers, the transmitter sends the sparsest representation of the transmitted codeword. Furthermore, we provide a sub-carrier selection and power control procedures to maximize the sum rate of SNOFDM according to CSI fed back from receivers to source node. Our numerical results show that SNOFDM offers better spectral efficiency and a higher secrecy rate compared to OFDM. We provide extensive simulation results to study the effects of transmission parameters of SNOFDM on the achievable secrecy rate.
Highlights
Security and confidentiality of communication are critical concerns in wireless networks
NUMERICAL RESULTS we provide numerical results to evaluate the performance of secure sparse non-orthogonal frequency division multiplexing (SNOFDM) transmission over a twouser broadcast channel with confidential messages (BCCM)
We conclude that SNOFDM approaches the bit error rate (BER) performance of orthogonal frequency division multiplexing (OFDM), while having better spectral efficiency
Summary
Security and confidentiality of communication are critical concerns in wireless networks. Cryptographic algorithms, e.g., data encryption standard (DES) and Advanced encryption standard (AES), Rivest-Shamir-Adelman (RSA) and Elliptic Curve Cryptosystem (ECC) algorithms [2], [3] are employed to ensure secure transmission of information [4] In this case, a transmitter uses an encryption key to convert the confidential message (a.k.a., the plaintext) into an encrypted version (a.k.a., the ciphertext). Our numerical results reveal that: 1) SNOFDM outperforms OFDM in terms of the sum rate This is since the SNOFDM requires less spectral resources, while the intra-carrier interference effect is minor as a result of the sparse nature of the transmitted signal, 2) Coupled with practical modulation schemes (e.g., QPSK), SNOFDM shows a little degradation in BER performance compared to OFDM.
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