arXiv subjects

Chinmoy Kundu

Publications and source records attributed to Chinmoy Kundu.

24 records · Page 2Linked to original sources

arXiv2021

Secrecy Performance of Small-Cell Networks with Transmitter Selection and Unreliable Backhaul under Spectrum Sharing Environment

We investigate the secrecy performance of an underlay small-cell cognitive radio network under unreliable backhaul connections. The small-cell network shares the same spectrum with the primary network, ensuring that a desired outage probability constraint is always met in the primary network. {To improve the security of the small-cell cognitive network, we propose three sub-optimal small-cell transmitter selection schemes,} namely sub-optimal transmitter selection, minimal interference selection, and minimal eavesdropping selection. Closed-form expressions of the non-zero secrecy rate, secrecy outage probability, and ergodic secrecy capacity are provided for the schemes along with asymptotic expressions. {We also propose an optimal selection scheme and compare performances with the sub-optimal selection schemes.} {Computable expressions for the non-zero secrecy rate and secrecy outage probability are presented for the optimal selection scheme.} Our results show that by increasing the primary transmitter's power and the number of small-cell transmitters, the system performance improves. The selection scheme, the backhaul reliability, and the primary user quality-of-service constraint also have a significant impact on secrecy performance.

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arXiv2021

Transmitter Selection for Secrecy in a Frequency Selective Fading Channel with Unreliable Backhaul

In this paper, a communication network using single carrier with cyclic prefix modulation over frequency selective channels is considered, where an access point provides connectivity to a legitimate destination through multiple transmitters with unreliable backhaul links in the presence of an eavesdropper. A sub-optimal and an optimal transmitter selection scheme are proposed to improve the secrecy of the system, depending on whether the active backhaul channel knowledge is available a priori or not. The secrecy outage probability (SOP) and its asymptotic limit are presented in closed-form. This provides some insights regarding how knowledge of the active backhaul links affects the secrecy performance of the network. Our results show that the optimal transmitter selection scheme obtains a larger benefit than the sub-optimal scheme from the knowledge of the active backhaul links, resulting in a significantly improved system performance; however, the sub-optimal transmitter selection scheme can reduce the complexity and feedback overhead.

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arXiv2021

Transmitter Selection for Secrecy in Cognitive Small-Cell Networks with Backhaul Knowledge

A small-cell network with multiple transmitters and unreliable wireless backhaul is considered for secrecy enhancement. The small-cell network is operating under a spectrum sharing agreement with a primary network in a cognitive radio system. A constraint on the desired outage probability at the primary receiver is assumed as a part of the spectrum sharing agreement. The reliability of the wireless backhaul links are modeled by a set of independent and identically distributed Bernoulli random variables. A sub-optimal and an optimal small-cell transmitter selection (TS) scheme is proposed to improve the performance of the system, depending on the availability of channel state information. Selection schemes are designed for the scenario where knowledge is available regarding which backhaul links are active. The corresponding secrecy outage probabilities along with their asymptotic expressions are derived. It is shown that the secrecy performance is significantly improved compared to the case where knowledge of the active backhaul links is unavailable.

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arXiv2021

Recurrent Neural Network Assisted Transmitter Selection for Secrecy in Cognitive Radio Network

In this paper, we apply the long short-term memory (LSTM), an advanced recurrent neural network based machine learning (ML) technique, to the problem of transmitter selection (TS) for secrecy in an underlay small-cell cognitive radio network with unreliable backhaul connections. The cognitive communication scenario under consideration has a secondary small-cell network that shares the same spectrum of the primary network with an agreement to always maintain a desired outage probability constraint in the primary network. Due to the interference from the secondary transmitter common to all primary transmissions, the secrecy rates for the different transmitters are correlated. LSTM exploits this correlation and matches the performance of the conventional technique when the number of transmitters is small. As the number grows, the performance degrades in the same manner as other ML techniques such as support vector machine, $k$-nearest neighbors, naive Bayes, and deep neural network. However, LSTM still significantly outperforms these techniques in misclassification ratio and secrecy outage probability. It also reduces the feedback overhead against conventional TS.

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arXiv2018

Secrecy Outage of Proactive Relay Selection by Eavesdropper

In this paper, we consider an active eavesdropping scenario in a cooperative system consisting of a source, a destination, and an active eavesdropper with multiple decode-and-forward relays. Considering an existing assumption in which an eavesdropper is also a part of network, a proactive relay selection by the eavesdropper is proposed. The best relay which maximizes the eavesdropping rate is selected by the eavesdropper. A relay selection scheme is also proposed to improve the secrecy of the system by minimizing the eavesdropping rate. Performances of these schemes are compared with two passive eavesdropping scenarios in which the eavesdropper performs selection and maximal ratio combining on the relayed links. A realistic channel model with independent non-identical links between nodes and direct links from the source to both the destination and eavesdropper are assumed. Closed-form expressions for the secrecy outage probability (SOP) of these schemes in Rayleigh fading channel are obtained. It is shown that the relay selection by the proactive eavesdropper is most detrimental to the system as not only the SOP increases with the increase in the number of relays, but its diversity also remains unchanged.

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arXiv2018

Effects of CSI Knowledge on Secrecy of Threshold-Selection Decode-and-Forward Relaying

This paper considers secrecy of a three node cooperative wireless system in the presence of a passive eavesdropper. The threshold-selection decode-and-forward (DF) relay is considered, which can decode the source message correctly only if a predefined signal-to-noise ratio (SNR) is achieved. The effects of channel state information (CSI) availability on secrecy outage probability (SOP) and ergodic secrecy rate (ESR) are investigated, and closed-form expressions are derived. Diversity is achieved from the direct and relaying paths both at the destination and at the eavesdropper by combinations of maximal-ratio combining (MRC) and selection combining (SC) schemes. An asymptotic analysis is provided when each hop SNR is the same in the balanced case and when it is different in the unbalanced case. The analysis shows that both hops can be a bottleneck for secure communication; however, they do not affect the secrecy identically. While it is observed that CSI knowledge can improve secrecy, the amount of improvement for SOP is more when the required rate is low and for ESR when the operating SNR is also low. It is also shown that the source to eavesdropper link SNR is more crucial for secure communication.

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