Sangseok Yun

On the Secrecy Rate and Optimal Power Allocation for Artificial Noise Assisted MIMOME Channels

This paper considers the artificial noise (AN) scheme, proposed by Goel and Negi for securing wireless communications over multiple-input multiple-output multiantenna eavesdropper (MIMOME) channels. In this paper, we develop a lower bound on the ergodic secrecy rate of the AN scheme and derive an analytic expression of the bound without assuming any asymptotes for system parameters. Thus, the derived bound explicitly elucidates how the system parameters exert influence on the secrecy rate in various cases to some of which the previous work cannot be applied. It will also be shown that the bound is tight over wide combinations of system parameters, and a normalized difference between the bound and secrecy rate vanishes with a growing number of antennas at the transmitter. The derived bound is analytically so amenable that it enables one to not only extend the results of the previous work but also explore untouched aspects of the AN scheme. The bound answers an intriguing question: When is the AN signal beneficial? Besides, it makes possible to study a new important system parameter called the minimum required transmit power for a certain target secrecy rate, which has never been touched before.

On the Secrecy Rate of Artificial Noise Assisted MIMOME Channels with Full-Duplex Receiver

This paper studies a secure communication over multiple-input multiple-output multi-antenna eavesdropper (MIMOME) channels which consist of legitimate parities, namely a transmitter and receiver, equipped with multi-antennas and a passive eavesdropper with multi-antennas. For securing the communication between the legitimate parties, we consider an artificial noise (AN) scheme in which the legitimate transmitter sends its secret messages and AN signal together. Meanwhile, it is assumed that the legitimate receiver has a full-duplex capability which enables it to capture the secret message from the transmitter and simultaneously generate a jamming signal to strengthen security. While there have been studies on similar setups, most of them focus on the design of the jamming signal with the assumption of full channel-state information (CSI) and#x002F;or system parameter optimization based on numerical evaluations. On the contrary, in this work, we instead introduce a tight lower bound on an achievable ergodic secrecy rate as a versatile analytic tool and derive a closed-form expressions for the bound. To confirm the analytic results, we carry out numerical evaluations of the ergodic secrecy rate which are compared with the proposed lower bound.

Detection of pilot contamination attack in the MU-MISOME broadcast channels

This work presents a detector for a pilot contamination attack (PCA) in multi-user time-division duplex (TDD) wireless networks. We consider a scenario in which an active eavesdropper with multiple antennas attempts a PCA to a Multiple-Input-Single-Output (MISO) target system. To fend off the PCA, we propose a PCA detector which exploits an imbalance between estimated channels in two-way training phases. Performance of the detector is analyzed in terms of detection probability. Numerical evaluations are also conducted for various combinations of system parameters to verify the analytic results.

Secure code design for near field communications

This paper discusses a design rule of secure code over binary-erasure wiretap channels. The main objective of this work is to introduce our early work for the reader interested in practical secure code designs. The design rule introduced in this work is based on the coset coding scheme and generalized Hamming weights by taking advantage of a bounding technique. The bounding technique significantly simplifies the design of secure codes at various lengths, which has been known to require prohibitive complexity when secure codes are at lengths of practical interest.

A real-time implementation of interference neutralization for multi-source multi-hop wireless networks

Interference neutralization (IN) is a promising multi-hop cooperative transmission technique for future wireless networks, which cancels co-channel interference caused by multiple sources with the help of multiple relay nodes. This paper presents the first real-time implementation of IN using software defined-radio testbed based on MATLAB/Simulink and Universal Software Radio Peripheral (USRP) platform. The testbed is used to demonstrate the feasibility of IN and to compare its networks sum-rates with conventional multi-hop transmission strategies. Measured results show that we are able to successfully achieve over-the-air IN in real-world settings. We believe that IN technology can be well applied to consumer mobile communication devices, such as smart phones, tablets, etc, in infrastructure assisted ad-hoc or future cellular networks.

Robustness of Biologically Inspired Pulse-Coupled Synchronization against Static Attacks

Biologically inspired pulse-coupled synchronization has received increasing attention as one of key techniques for developing decentralized wireless networks due to its inherent scalability and simplicity. While it has been actively studied in recent years, most of the previous works have focused on the synchronization only in fault/attack free networks. However, in reality, a network may have malfunctioning nodes and/or attackers, and thus robustness against these threats in the pulse- coupled synchronization must be an important practical issue on its path to realization. Motivated by this, we analyze the influence of attackers behaviors in a network of pulse-coupled oscillators. The analysis shows that when the number of attackers is less than a certain number, i.e. a threshold, the network sustains its synchronization. Moreover, the threshold is proportional to both of coupling strengths among the pulse-coupled oscillators and the number of legitimate oscillators. Finally, numerical experiments are given to confirm the analytic results.