Basak Guler

Modeling Human Aspects of Communication

Emerging networks such as the Internet of Things (IoT) are designed to facilitate the interaction of humans with intelligent machines. These networks consist of actors with possibly different characteristics, goals, and interests. Such differences can in turn lead to various interpretations of the received information. I design networks that operate under such ambiguous environments, by leveraging the semantic and social features of information transmission. Unlike conventional communication networks, this necessitates taking into account the personal background and characteristics of the interacting parties.

Related publications:

Basak Guler, Aylin Yener, Ebrahim MolavianJazi, Prithwish Basu, Ananthram Swami, Carl Andersen, Interactive Function Compression with Asymmetric Priors, Proceedings of the IEEE Data Compression Conference, DCC'16, Snowbird, UT, Mar. 2016.

Basak Guler, Deniz Gündüz, and Aylin Yener, Lossy Transmission of Correlated Sources over a Multiple Access Channel: Necessary Conditions and Separation Results, IEEE Transactions on Information Theory, 64(9), pp. 6081-6097, Sep. 2018.

Basak Guler, Ebrahim MolavianJazi, Aylin Yener, Remote Source Coding with Two-Sided Information, Proceedings of the IEEE International Symposium on Information Theory, ISIT'15, Hong Kong, Jun. 2015.

Basak Guler, Aylin Yener, Compressing Semantic Information with Varying Priorities, Proceedings of the IEEE Data Compression Conference, DCC'14, Snowbird, UT, Mar. 2014.

Basak Guler, Aylin Yener, Ananthram Swami, Learning Causal Information Flow Structures in Multi-Layer Networks, Proceedings of the IEEE GlobalSIP Symposium on Non-Commutative Theory and Applications, GlobalSIP'16, Washington DC, Dec. 2016.

Basak Guler, Aylin Yener, Prithwish Basu, Carl Andersen, Ananthram Swami, A Study on Compressing Graphical Structures, Proceedings of the IEEE Global Conference on Signal and Information Processing - Symposium on Network Theory, GlobalSIP'14, Atlanta, GA, Dec. 2014.

Semantics-Aware Information Transfer in the Physical Layer

Modern networked systems allow interaction between humans and physical objects with various processing and inference capabilities. For these networks, reliable communication implies that the intended meaning of messages is preserved at reception. In effect, this new generation of networks supports interaction at a level that communicating parties can form social relationships and build trust, which may further affect how the received messages are interpreted. In contrast, communication protocols that operate in the physical layer do not take into account the difference between the meanings of transmitted and recovered messages, but rather are concerned with the engineering problem of reliably communicating sequences of bits to the receiver. These factors together motivate a new approach that molds physical and application layer metrics into one, i.e., a novel performance criterion that takes into account the meanings of the communicated messages. I design mechanisms to achieve this, i.e., how to reliably communicate the meanings of messages through a noisy channel.

We introduced the first joint source-channel coding models for transmitting semantic messages over a physical channel, such as text, while preserving their meanings.

An external influential entity, who can influence how the destination perceives the received information, is considered, to model the impact of social influence on how the messages are interpreted. The exact nature of the individual, whether adversarial or helpful, is unknown to the communicating parties. An individual with such influence capability can have a significant impact on information recovery, hence transmission policies should be tailored to take into account the uncertainty in the intentions of such influential entities.

Related publications:

Basak Guler, Aylin Yener, and Ananthram Swami,  The Semantic Communication Game, IEEE Transactions on Cognitive Communications and Networking, accepted Sep. 2018.

Basak Guler, Aylin Yener, Ananthram Swami, The Semantic Communication Game, Proceedings of the IEEE International Conference on Communications, ICC'16, Kuala Lumpur, Malaysia, May 2016.

Basak Guler, Aylin Yener, Semantic Index Assignment, Proceedings of the Sixth International Workshop on Information Quality and Quality of Service for Pervasive Computing (IQ2S'14) in Conjunction with IEEE PERCOM 2014, Budapest, Hungary, Mar. 2014.

Social Influence and Recommendation Systems: An Information-Theoretic View

An important aspect of information transfer in networks subject to human factors is social influence. In other words, how a person reacts to the messages is affected by the actions of others in the community. In this work, we address how to characterize the influence of one person's actions on the actions of another person from an information-theoretic perspective. To do so, we model the social network as a channel with feedback in which the actions taken by users affect the future actions of their friends, and measure social influence via directed information. In order to determine the theoretical limits of the influence that an entity who can make personalized suggestions, such as a recommender, has in the social network, maximizing the recommender's influence is related to finding the capacity of a finite state channel with causal feedback. Accordingly, we identify the optimal recommendation strategies a recommender can adopt to maximize its influence over the social network when persons are influenced by their neighbors in responding to the recommender's suggestions.

Related publications:

Basak Guler, Kaya Tutuncuoglu, Aylin Yener, Maximizing Recommender's Influence in a Social Network: An Information-Theoretic Perspective, Proceedings of the IEEE Information Theory Workshop, ITW'15, Jeju Island, Korea, Oct. 2015.

Heterogeneous Wireless Networks: Interference Management

A heterogeneous wireless network is an environment that consists of cellular base stations of various sizes, coverage areas, and operating protocols. Some of these are installed and maintained by the mobile operator, such as macrocells (cellular towers), while the others are plug-and-play devices installed by the users, such as femtocells.

This ad-hoc nature of deployment makes interference management across different tiers a challenge for mobile operators. I addressed this problem in a two-tier network that involves femtocells in addition to macrocells. Mobile user devices as well as base stations are deployed with multiple antennas, which creates spatial dimensions that can be used for interference cancellation or data rate increase. To alleviate cross-tier interference, interference received from the macrocell users can be aligned in a small dimensional subspace at multiple femtocells, while simultaneously ensuring that the performance requirements of the macrocell users are satisfied. This can enable coexistence with high data rates even at very high interference levels, when communication would be impossible otherwise.

Related publications:

Basak Guler, Aylin Yener, Uplink Interference Management in Coexisting MIMO Femtocell and Macrocell Networks: An Interference Alignment Approach, IEEE Transactions on Wireless Communications, vol. 13, no. 4, pp. 2246-2257, Apr. 2014.

Basak Guler and Aylin Yener, Selective Interference Alignment for MIMO Cognitive Femtocell Networks, IEEE Journal in Selected Areas in Communications: Cognitive Radio Series, vol. 32, no. 3, pp. 439-450, Mar. 2014.

Basak Guler and Aylin Yener, Selective Interference Alignment for MIMO Femtocell Networks, Proceedings of the IEEE International Conference on Communications, ICC'13, Budapest, Hungary, Jun. 2013.

Basak Guler and Aylin Yener, Interference Alignment for Cooperative MIMO Femtocell Networks, Proceedings of the IEEE Global Communications Conference, Globecom'11, Houston, TX, Dec. 2011.