Theoretische Grundlagen der Kommunikationstechnik

Invitation to a Mini-Workshop in preparation of ISIT 2015

TimeThu, 11-06-2015, 4-6pm, HFT building  
Location6th floor, Room 617, Einsteinufer 25, 10587 Berlin  

An oral presentation and short discussion with:

 1)  Dr. Xinping Yi (TU-Berlin) at 4pm

Title: On the Optimality of Treating Interference as Noise: A Combinatorial Optimization Perspective

Abstract: For single-antenna Gaussian interference channels, we re-formulate the problem of determining the Generalized Degrees of Freedom (GDoF) region achievable by treating interference as noise (TIN) with proper power controlfrom a combinatorial optimization perspective. We show that the TIN power control problem can be cast into an assignment problem, such that the globally optimal power allocation variables can be obtained by well-known polynomial time algorithms. Furthermore, the expression of the TIN-achievable GDoF region can be substantially simplified with the aid of maximum weighted matchings. In addition, we provide conditions under which the TIN-achievable GDoF region is a convex polytope that relax those in literature. For these new conditions, together with a channel connectivity (i.e., interference topology) condition, we can prove GDoF optimality for a new class of interference networks that is not included, nor includes, the class found in literature.

2) Dr. Kittipong Kittichokechai (TU-Berlin) at 4.30pm

Title: Secret key-based Authentication with a Privacy Constraint

Abstract: We consider problems of user authentication base on secret key generation under a privacy constraint on the enrolled source data.  An adversary who has access to the stored description and correlated side information can try to deceive the authentication as well as learn about the source. The optimal performance-security tradeoff of two related problems are characterized. They reveal a connection between the optimal secret key rate and security of the authentication system. The setup can be relevant for different access control applications, including secure biometric authentication and hardware based authentication. 

3) Rick Fritschek, M.Sc. (TU-Berlin) at 5pm

Title: Constant-Gap Sum-Capacity Approximation of the Deterministic Interfering Multiple Access Channel

Abstract: A recent investigation has shown a constant-gap sum-capacity result for the constant single-antenna Gaussian X-channel. A novel deterministic model, called LTDM, was used to approximate the channel and later-on transfer these results to the Gaussian channel. We will show, that the LTDM can be applied to the Gaussian interfering MAC (IMAC) as well. This solves challenges of previous deterministic models and yields a constant-gap sum-capacity approximation for the deterministic IMAC.

4) Dr. Saeid Haghighatshoar (TU-Berlin) at 5.30 pm

Title: Asynchronous Decoding of LDPC Codes over BEC

Abstract: In this paper, we investigate the effect of asynchronous message passing on the decoding of LDPC codes over a Binary Erasure Channel (BEC). We effectively assume that there is a random delay assigned to each edge of the factor graph that models the random propagation delay of a message along the edge. As a result, the output messages of a check/variable node are also asynchronously updated upon arrival of a new message in its input. We show, for the first time for BEC, that the asymptotic performance of the asynchronous message passing is fully characterized by a fixed point integral equation that takes into account both the temporal and the spatial features of the factor graph. Our theoretical result is reminiscent of the fixed point equation in traditional BP decoding. Also, our simulation results show that asynchronous scheduling reduces decoding time compared to the traditional BP in certain cases in the finite block-length regime.