Digitale Kommunikationssysteme

Robust Design

Robust design of signal processing and communication devices refers to idea of successfull operation in uncertain environments as well as simplicity in the complexity resulting in less requirements for successfull operation.

In particular, we are interested in

  • robust beamforming
  • joint channel estimation and codebook design
  • minimal feedback
  • linear methods
  • semi-blind wiretap approaches

and their optimality with respect to fundamental bounds. For instance, the generalized degreess of freedom perspective (GDoF), which is a first order approximation of the capacity, i.e., the highest reliable communication rate, is a metric used in some of our work to prove optimality.


In the following illustration, the optimality of treating interference as noise (TIN) for the multiple interference channel with partial interference (PIMAC) from the GDoF perspective is demonstrated. The PIMAC is an fundamental element in any cellular network.  The results are quite interesting. For istance, in certain cases the interference can be arbitrarily small and still TIN is optimal. Yet, in other cases, the interference is strong, but the best you can do is to apply TIN.   By modifiying the channel gains (in dB scale) , you can see the effect on the TIN optimality region.


The parameters, setup and the results are discussed in more details here.




Overview talk: Optimality of TIN

Overview slides on the optimality of treating interference as noise (TIN) for general networks:

Optimality of TIN


Considering the development of wireless communication systems, we observe that information theoretic methods and concepts prevail in the long run.  They are many examples, starting from Turbo-Codes, LDPC-Codes, Polar-Codes, to MIMO, OFDM, opportunistic scheduling and so on.  However, as complexity plays a big role in the design and cost of such systems, simple strategies (in terms of computational complexity) are often preferred in practice. Thus, there appears to be a huge discrepancy between what is done in practice and the optimal thing to do. In this talk, we discuss about changing the perspective and ask whether conditions exist in which the low cost and simple methods used in practice are information theoretically optimal, i.e., they achieve capacity? That is, there is no need to refer to more complicated schemes as those are not able to outperform the simple schemes, as long as those conditions hold.  Motivated by this idea and recent results on the approximate capacity of the two-user interference channel, an elemental network to investigate the impact of interference, we consider generalized networks, such as interfering MAC (multiple access channels) and X networks, and determine the approximate optimality of treating interference as noise (TIN).  Compared to other practical methods, such as avoiding interference and suppressing interference, treating interference as noise needs minimum coordination and is thus quite efficient and robust. Now, for the characterization of the approximate optimality we use the method of linear-deterministic models to determine sharp upper bounds in terms of generalized degrees of freedom, which is a first-order approximation of the capacity.  We use those bounds to provide conditions under which treating interference as noise is optimal. We also show that there is a duality in terms of TIN-optimality in MxN and NxM X networks for min(N, M)=2.  The talk has copious illustrations with a minimum mathematical content. The aim is to build intuition and insight while leaving the technical details to references.

Our contributions

Author / Editor / Organization Titel Year Download / Bibtex
1 J. Kakar , A. Sezgin A Survey on Robust Interference Management in Wireless Networks Link
1 A. Chaaban , A. Sezgin Multi-hop Relaying: An End-to-End Delay Analysis BibTeX
2 A. Chaaban , A. Sezgin When Can a Relay Reduce End-to-End Communication Delay? BibTeX
1 J. Kakar , Kevin McDermott , Vidur Garg , Marc Lichtman , Vuk Marojevic , Jeffrey H. Reed Analysis and Mitigation of Interference to the LTE Physical Control Format Indicator Channel Link
2 S. Gherekhloo , A. Chaaban , A. Sezgin Resolving Entanglements in Topological Interference Management with Alternating Connectivity Download
3 S. Gherekhloo , A. Chaaban , A. Sezgin Coordination gains in the cellular uplink with noisy interference Download
4 S. Gherekhloo , A. Chaaban , A. Sezgin Topological Interference Management with Alternating Connectivity: The Wyner-Type Three User Interference Channel Download
1 A. Chaaban , A. Sezgin Sub-optimality of Treating Interference as Noise in the Cellular Uplink BibTeX
1 B. Bandemer , A. Sezgin , A. Paulraj On the Noisy Interference Regime of the MISO Gaussian Interference Channel Download
2 A. Sezgin , E. A. Jorswieck , E. Costa LDC in MIMO Ricean Channels: Optimal transmit strategy with MMSE detection Download
3 E. A. Joswieck , A. Sezgin , B. Ottersten , A. Paulraj Feedback Reduction in Uplink MIMO OFDM Systems by Chunk Optimization Download
1 A. Sezgin , M. Vu , A. Paulraj Impact of correlation on linear precoding in QSTBC coded systems with linear MSE detection BibTeX
1 M. Schellmann , A. Sezgin , G. Wunder , H. Halbauer , R. Muenzner Performance of the WiMAX Ranging Process in high mobility environments BibTeX
2 E. A. Joswieck , A. Sezgin , Y. Gao , D. Kim On the tradeoff between feedback signaling and performance for tile based MIMO-OFDMA systems BibTeX
3 A. Sezgin , P. Jung , M. Schellmann , H. Halbauer , R. Muenzner On the impact of mobility on the channel estimation in WiMAX OFDMA-Uplink BibTeX
4 E. A. Joswieck , A. Sezgin , H. Boche , E. Costa Multiuser MIMO MAC with Statistical CSI and MMSE Receiver: Feedback Strategies and Transmitter Optimization BibTeX
5 A. Sezgin , E. A. Joswieck , H. Boche On the average rate of precoded QSTBC in MIMO channels with Non-Zero Mean BibTeX
6 A. Sezgin , E. A. Joswieck , H. Boche , E. Costa Utilizing Channel Mean Information with MMSE detection for LDC in MIMO systems BibTeX
1 A. Sezgin , E. A. Joswieck , E. Costa Optimal transmit strategies for QSTBC in MIMO Ricean Channels with Linear Detection BibTeX
1 E. A. Joswieck , H. Boche , A. Sezgin Delay-limited capacity and maximum throughput of spatially correlated multiple antenna systems under average and peak-power constraint Link
2 E. A. Joswieck , A. Sezgin , H. Boche , E. Costa Optimal transmit strategies in MIMO Ricean Channels with MMSE Receiver BibTeX
3 E. A. Jorswieck , A. Sezgin Impact of Spatial Correlation on the Performance of Orthogonal Space-Time Block Codes Download
1 A. Sezgin , E. A. Joswieck Joint Decoding and Channel Estimation for Low-complexity STC BibTeX