Broadcast channel (BC) faces critical physical layer security (PLS) challenges due to their inherent openness. Traditional encryption methods are costly and unsuitable for low-latency applications. Recent studies have shown that Schalk-wijk-Kailath (SK) feedback coding scheme naturally satisfies PLS and achieves double-exponential error decay. This paper investigates two-user Single-Input Multiple-Output (SIMO) broad-cast wiretap channel with partial feedback. A SK-type feedback control scheme based on scalarization and channel splitting is proposed for the two-user SIMO broadcast wiretap channel. Finially, numerical results demonstrate that the proposed scheme outperforms existing secret-key-based methods in the literature.
Broadcast channel (BC) faces critical physical layer security (PLS) challenges due to their inherent openness. Traditional encryption methods are costly and unsuitable for low-latency applications. Recent studies have shown that Schalk-wijk-Kailath (SK) feedback coding scheme naturally satisfies PLS and achieves double-exponential error decay. This paper investigates two-user Single-Input Multiple-Output (SIMO) broad-cast wiretap channel with partial feedback. A SK-type feedback control scheme based on scalarization and channel splitting is proposed for the two-user SIMO broadcast wiretap channel. Finially, numerical results demonstrate that the proposed scheme outperforms existing secret-key-based methods in the literature.
The two-user Gaussian broadcast wiretap channel with common message and feedback (GBC-WTC-CM-F) is revisited. Traditionally, achievable secrecy rate of this model is achieved by combining Marton’s coding scheme for the two-user broadcast channel (BC) and the secret-key based feedback scheme, where both of the two feedback links are used to transmit secret keys shared between the transceivers. Recently, it has been shown that for the Gaussian wiretap channel with feedback, the Schalkwijk-Kailath (SK) feedback scheme achieves its secrecy capacity. Then it is natural to ask: can we do better when applying the SK-type scheme to the GBC-WTC-CM-F? In this paper, we answer this question by proposing two kinds of SK-type schemes. Specifically, first, we propose a hybrid scheme where one feedback link is used to transmit a secret key, and the other one is used for SK-type coding. We show that this hybrid scheme may perform better than the existing one in some cases. Next, we show that Ozarow’s extended SK scheme for the two-user Gaussian BC with feedback, where both feedback links are used for SK-type coding, is self-secure (satisfying perfect weak secrecy constraint by itself) and may perform the best. We further show that Ozarow’s scheme is in fact a secure finite blocklength coding scheme, and extend it to the static fading SISO and SIMO cases. Finally, the results of this paper are further explained by numerical examples.
In the literature, it has already been shown that a feedback control based coding scheme enhances the secrecy capacity of the Gaussian broadcast wiretap channel (GBC-WTC) with common message, and it performs better than the conventional random key based feedback scheme. However, note that the previously proposed scheme is based on the assumption that both the two receivers can send their received signals back to the transmitter via two feedback channels, which may not be available when a certain feedback channel fails to work. In this paper, we study the GBC-WTC with common message and partial feedback, where only one legitimate receiver can send his received signal back to the sender via a perfect feedback channel. A hybrid scheme, which combines the classical Schalkwijk-Kailath (SK) feedback control scheme, a dirty paper pre-coding scheme and the conventional random binning scheme is proposed for this model. Numerical results show that even in such a partial feedback case, our proposed scheme still works well and outperforms the existing secret-key based scheme in the literature.
The current feedback coding strategy for the physical layer security (PLS) mainly focuses on generating secret key used for protecting the transmitted message, and this strategy has been proved only optimal for several degraded cases. Our previous work has proposed a new hybrid feedback strategy for the classical PLS model-the wiretap channel (WTC), where the feedback is not only used to generate key, but also used to produce cooperative information helping the legitimate parties to improve the communication between them. It has been shown that for the general WTC, this hybrid feedback strategy performs better than the already existing secret key based feedback scheme. In this paper, we extend the previous proposed feedback strategy for the WTC to a multi-terminal case, and apply this generalized feedback strategy to the broadcast channel with mutual secrecy requirement (BC-MSR), which constitutes the essence of physical layer security (PLS) in the down-link of the wireless communication systems. From a non-degraded example (Dueck-type broadcast channel), we show that for the BC-MSR, this generalized feedback strategy may perform better than the already existing one.
Recently, the physical layer security (PLS) of the communication systems has been shown to be enhanced by using legal receiver's feedback. The present secret key based feedback scheme mainly focuses on producing key from the feedback and using this key to protect part of the transmitted message. However, this feedback scheme has been proved only optimal for several degraded cases. The broadcast channel with mutual secrecy requirement (BC-MSR) is important as it constitutes the essence of physical layer security (PLS) in the down-link of the wireless communication systems. In this paper, we investigate the feedback effects on the BC-MSR, and propose two inner bounds and one outer bound on the secrecy capacity region of the BC-MSR with noiseless feedback. One inner bound is constructed according to the already existing secret key based feedback coding scheme for the wiretap channel, and the other is constructed by a hybrid coding scheme using feedback to generate not only keys protecting the transmitted messages but also cooperative messages helping the receivers to improve their decoding performance. The performance of the proposed feedback schemes and the gap between the inner and outer bounds are further explained via two examples.
Abstract Physical layer security (PLS), which is based on information-theoretic principles of message confidentiality, has attracted considerable attention in recent years. This paper provides a comprehensive survey of using channel feedback (CF) to enhance the quality of PLS of various communication models. To be specific, the survey starts from the secret key-based CF scheme and its variations for the wiretap channel (WTC) and other communication models. Then, for the WTC and its generalized models, an improved feedback scheme and its variations are respectively introduced, where the improved scheme combines the secret key-based CF scheme with the Wyner-Ziv scheme for source coding with side information. It has been shown that these improved schemes perform better than the original secret key-based schemes for several cases. Next, the Schalkwijk-Kailath (SK) feedback scheme and its variations are introduced, which are optimal for the Gaussian WTC and its variations. Finally, the already existing CF schemes are summarized and the future challenges of using CF to enhance PLS are discussed.
In this paper, an efficient and self-secure channel feedback scheme for single-input multiple-output (SIMO) system based on Rayleigh channel is studied. In this paper, the classical SK scheme is extended to SIMO Rayleigh channel and wire-tap channel, and we prove that the extended scheme is self-secure capacity-achieving(SSCA). Numerical results show that this scheme achieves extremely low decoding error probability under especially small codeword length and significantly enhances the physical layer security in SIMO Rayleigh channel.