Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - CloudRadioNet (Cloud Wireless Networks: An Information Theoretic Framework)

Teaser

This research project is focused on the development of novel information theoretic concepts and techniques and their usage, as to identify the ultimate communications limits and potential of different cloud radio access networks (C-RAN) structures, in which the central signal...

Summary

This research project is focused on the development of novel information theoretic concepts and techniques and their usage, as to identify the ultimate communications limits and potential of different cloud radio access networks (C-RAN) structures, in which the central signal processing is migrated from the radio units to the cloud (remote central units), via fronthaul/backhaul infrastructure links. Moreover, it is directed also, to introduce and study the optimal or close to optimal strategies for those systems that are to be motivated by the developed theory.
We focus on wireless networks, having future cellular technology in mind, but the basic tools and approaches to be built and researched are relevant to other communications networks as well.
Cloud communication networks motivate novel information theoretic views, and perspectives which put in center backhaul/fronthaul connections deviating thus considerably from standard theoretical studies of communications links and networks, which is applied to this domain.

The theoretical understanding which results from this research will facilitate the design and implementation of efficient, robust and reliable communications techniques, the demand for which is steadily increasing.
The change of paradigms from \'how to do\' to \'what to do\' due to the available advanced technologies turns the information theoretic understanding to a leading practical tool, guiding the constriction of advanced communications networks.

Our achievements addressing these basic theoretical questions, so far account for:

* Information Theoretic perspective of up and down link C-RAN: New technologies, concepts and information theoretic characterization.

* Fog radio access networks: an information theoretic view

* Network information theoretic view:

- Cooperative networks: The impact of cooperation on performance enhancement, as measured via an information theoretic approach, examined for simple cellular models and understanding the theoretical impact of number of
cooperation rounds.

- Physical layer secrecy over cooperative and C-RAN networks.

* Networks, processing and practical implications:

- An Information-estimation view of communications networks, accounting for the impact of cognition and cooperation.

Work performed

Our research achievement so far addresses a wide spectrum of C-RAN related aspects, and the achievements as specified are not only of primary theoretical importance, but do carry practical implications.
Here we detail in short (space limitations): the central direct achievements, which account for a wide scope of information theoretic analysis of C-RAN and its network components, as is reflected by the journals papers’ title.

These studies reflect our work and results so far all focused on the development of novel information theoretic concepts and techniques and their usage, as to identify the ultimate communications limits and potential of different cloud radio access networks (C-RAN) structures.
Specifically, our work so far has contributed significantly to the basic theoretical questions, we have posed:
*Information Theoretic perspective of up and down link C-RAN:
*Fog radio access networks: an information theoretic view *Cooperative networks: The impact of cooperation on performance enhancement, as measured via an information theoretic approach, examined for a variety of C-RAN and network related problems.
* Physical layer secrecy over cooperative and C-RAN networks
* An Information-estimation view of communications networks, accounting for the impact of cognition and cooperation.

S.-H. Park, O. Simeone and S. Shamai Shitz, “Time-Asynchronous Robust Cooperative Transmission for the Downlink of C-RAN,” IEEE Signal Processing Letters, Vol. 23, No. 10, October 2016.
S.-H. Park, O. Simeone and S. Shamai Shitz, “Joint Optimization of Cloud and Edge Processing for Fog Radio Access Networks,” IEEE Trans. on Wireless Communications, vol. 15, no. 11, pp. 7621-7632, 2016.
Y. Sun, R. Duan, Y. Liang, A. Khisti and S. Shamai (Shitz), “Capacity Characterization for State-Dependent Gaussian Channel With a Helper,” IEEE Transactions on Information Theory, vol. 62, no. 12, December 2016, Page(s):7123-7134.
M. Wigger, R. Timo and S. Shamai (Shitz), “Conferencing in Wyner’s Asymmetric Interference Network: Effect of Number of Rounds,” IEEE Trans. on Information Theory, vol. 63, no. 2, pp. 1199-1226, 2017.
Jinkyu Kang, O. Simeone, Joonhyuk Kang and S. Shamai, “Layered Downlink Precoding for C-RAN Systems With Full Dimensional MIMO,” IEEE Transactions on Vehicular Technology, Vol. 66, No. 3, March 2017.
Sheng Yang and S. Shamai (Shitz), “On the Multiplexing Gain of Discrete-Time MIMO Phase Noise Channels,” IEEE Transactions on Information Theory, vol. 63, no. 4, April 2017, pp. 2394-2408.
Chao Tian, Jun Chen, S. N. Diggavi and S. Shamai Shitz, “Matched Multiuser Gaussian Source Channel Communications via Uncoded Schemes,” IEEE Trans. on Information Theory, vol. 63, no. 7, pp. 4155-4171, 2017.
A. Dytso, R. Bustin, S. Shamai (Shitz) and H. V. Poor, “A View of Information-Estimation Relations in Gaussian Networks,” Entropy 2017, 19(8), 409.
Ain-ul-Aisha, Lifeng Lai, Yingbin Liang and Shlomo Shamai, “On the Sum-Rate Capacity of Poisson MISO Multiple Access Channels,” IEEE Trans. on Information Theory, vol. 63, no. 10, pp. 6457-6473, 2017.
Shirin Saeedi Bidokhti, Gerhard Kramer and Shlomo Shamai, “Capacity Bounds on the Downlink of Symmetric, Multi-Relay, Single-Receiver C-RAN Networks,” Entropy 2017, 19, 610.
A. Dytso, R. Bustin, D. Tuninetti, N. Devroye, H. V. Poor and S. Shamai (Shitz), “On Communication Through a Gaussian Channel With an MMSE Disturbance Constraint,” IEEE Trans. on Information Theory, vol. 64, no. 1, pp. 513-530, Jan. 2018.
Wenbo He, Bobak Nazer, and Shlomo Shamai (Shitz), “Uplink-Downlink Duality for Integer-Forcing,” IEEE Trans. on Information Theory, vol. 64, no. 3, pp. 1992-2011, March 2018.
Alex Dytso, Ronit Bustin, Daniela Tuninetti, Natasha Devroye, H.Vincent Poor, Shlomo Shamai (Shitz), “On the Minimum Mean p-th Error in Gaussian Noise Channels and its Applications,” IEEE Trans. on Information Theory, vol. 64, no. 3, pp. 2012-2037, March 2018.
Shaofeng Zou, Y

Final results

\"Our general research view accounts for the fact that in such C-RAN based networks information theoretic separation concepts are no more optimal, even if each component is based on state-of-the art theoretical results. Our theoretical view and results so far reflect novel analysis and techniques, which can be of use in general networks as communication viewed via the information-theoretic paradigm.
Thus, isolating simple basic components of the network is essentially suboptimal.
Our view in this research project, incorporates, in a unified way, under the general cover of information theory: Multi-terminal distributed networks; Basic and timely concepts of distributed coding and communications;
Network communications and primarily network coding, index coding, as associated with interference alignment and caching; Signal processing addressing directly the impact of distributed channel state information; A variety of fundamental concepts in optimization and random matrix theories.
One of the major concepts we pursue in our research, which has direct practical implications is robust (oblivious) processing at the radio (relay) units, where it is guaranteed to perform well in general and in this sense our approach reflects universal features,
which is not dependent on the communications/coding strategy used by the user equipment.
We have demonstrated that our theoretical concepts of oblivious cloud radio access connect to a variety of \"\"information bottleneck\"\" problems. These are of fundamental importance in other interdisciplinary domains such as deep and machine learning.

This path provides a natural theoretical framework directed towards better understanding of the potential and limitations of cloud networks on one hand and paves the way to innovative universal communications design principles and to theoretical impact on interdisciplinary domains such as the \"\"information bottleneck\"\" problem.


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Website & more info

More info: http://shamai.net.technion.ac.il/erc/.