RESET - Erreichbare Raten, Effiziente Sendeverfahren und Signalverarbeitung für das Broadcast Multihop-Netzwerk
Zusammenfassung der Projektergebnisse
The goal of the project RESET was to investigate new methods and concepts from information theory and signal processing for broadcast multi-hop networks which are important models for future communication networks. Exploiting the broadcast property of the wireless medium, physical layer network coding, also known as wireless or analog network coding, supports multi- and unicast traffic in the considered models. In order to decrease the complexity of the analysis, we divided the network into smaller pieces like the interference channel, the multi-way (relay) channel in which the source and the sink nodes have information to share. We also considered broadcast relay channels, in which the relays might have side information stored locally (caching) to improve the system performance. In more details, we investigated user cooperation in a cellular network by enabling device-to-device communication (D2D). D2D is a technique that is envisioned as a potential solution for meeting the high data-rate demand in the future cellular networks. The main idea of D2D is that devices within close proximity communicate with each other directly or act as relays that support other devices’ communication with the BS. The approach we pursued was to enable both uplink (UL) and downlink (DL) simultaneously over a given channel resource in a cellular setup. We showed that this can lead to better performance in terms of achievable rates since the coding scheme based on physical-layer network coding can be designed jointly for the UL and DL. Next, we considered smaller sized cells, such as femto- and picocells, as they are considered as a potential solution for power efficiency while increasing the supported bitrates for devices in such cells. In particular, we considered bi-directional two-way communication in a two-tier network, which is an elementary component of the heterogeneous network system. We investigated the performance of various schemes and compared their performance with fundamental information theoretic limits. We also investigated the impact of local storages (caches) for local servers in small cells. We proposed two strategies and optimized them with respect to their performance by casting the objective as an optimization problem and solved it approximately. We also investigated physical layer networking coding for general two hop relay networks, and in particular the achievable rates, the so called computation rates, and the corresponding optimization problem to find suitable network coding coefficients. The search for these is important and difficult, because they depend on the wireless fading channels. Both cooperative and non-cooperative solutions are proposed and compared. For centralized optimization an efficient branch and bound algorithm is implemented. The impact of transmit and receive correlation on the achievable sum-rate shows that strong correlation decreases the achievable sum-rate, however, a variant called subspace compute-and-forward shows superior performance for high correlation. Finally, an implementation of the compute-and-forward technique was demonstrated for a two-way relay channel on an open radio platform. Within the project, the PhD thesis "Compute-and-Forward in Multi-User Relay Networks. Optimization, Implementation, and Secrecy" by Dr. Johannes Richter was completed and successfully defended at TU Dresden. Additionally, two diploma theses and one student project were supervised at TU Dresden. At the Ruhr-University Bochum (RUB), the results obtained in the project resulted in contributions to two PhD theses. Furthermore, a master thesis was supervised at the RUB. Several publications (both journals and conference contributions) resulted as an outcome of the project.
Projektbezogene Publikationen (Auswahl)
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“An efficient branch-and-bound algorithm for compute-and-forward”. In: 23rd IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). Second Workshop on Network Coding in Wireless Relay Networks. Sept. 2012, pp. 77–82
J. Richter, C. Scheunert, and E. A. Jorswieck
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“Compute-and-Forward in the Two-Hop Multi-Antenna X-Channel”. In: 5th International Symposium on Communications Control and Signal Processing (ISCCSP). May 2012, pp. 1–4
E. A. Jorswieck and J. Richter
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“The Degrees-of-Freedom of Multi-way Device-to- Device Communications is Limited by 2”. In: Proc. of IEEE International Symposium on Info. Theory (ISIT), June 2014
A. Chaaban, H. Maier, and A. Sezgin
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“Multi-hop Relaying: An End-to-End Delay Analysis”. In: IEEE Trans. on Wireless Communications (Oct. 2015)
A. Chaaban and A. Sezgin
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“Non-Cooperative Compute-and-Forward Strategies in Gaussian Multi-Source Multi-Relay Networks”. In: IEEE 82nd Vehicular Technology Conference (VTC Fall). Sept. 2015, pp. 1–5
J. Richter, J. Hejtmánek, E. A. Jorswieck, and J. Sýkora
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“Compute-and-Forward in Multi-User Relay Networks. Optimization, Implementation, and Secrecy”. PhD thesis. Technische Universität Dresden, Fakultät Elektrotechnik und Informationstechnik, 2017
J. Richter
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“Full-Duplex vs. Half-Duplex: Delivery-Time Optimization in Cellular Downlink”. In: European Wireless, Dresden, Germany, May 2017
A. Kariminezhad, S. Gherekhloo, and A. Sezgin
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“Multi-flow Glossy: Physical-layer Network Coding Meets Embedded Wireless Systems”. In: 26th International Conference on Computer Communications and Networks (ICCCN). Aug. 2017
A. Abdelkader, J. Richter, E. A. Jorswieck, and Marco Zimmerling
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“Resource Cost Balancing with Caching in C-RAN”. In: IEEE WCNC, San Francisco, USA. 2017
A. Alameer and A. Sezgin
