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Annonce

7 mai 2018

Antenna selection techniques in massive MIMO for increasing the robustness of 5G communications to interferences


Catégorie : Post-doctorant


Mission: The candidate will first study antenna selection strategies in massive MIMO to combat different types of interferences. Their goal is to determine which antennas should be chosen for transmission, while others are deactivated in order to optimize the overall energy efficiency. In this context, he will consider several antenna deployment configurations: distributed, localized or hybrid.

The candidate will then develop techniques for detecting the sources of interference in the network, based on channel sounding techniques that will be tested using the MIMOSA sounder.

The next step will consist in combining antenna selection techniques with appropriate power allocation methods in such a way to minimize the influence of interference sources on the transmission quality.

Post-Doctorate subject

Title: Antenna selection techniques in massive MIMO for increasing the robustness of 5G communications to interferences.

Post-doctorate duration of 12 months:Preferably starting September2018.

Requested skills: Signal processing – Digital communications.

Host laboratory: IEMN (TELICE team), Villeneuve d'Ascq, France.

Supervising team: Eric Simon (MCF at IEMN) - Joumana Farah (professor at the Lebanese University).

Contact: Eric Simon, eric.simon@univ-lille.fr

Context

Today's mobile networks and their future evolutions towards the 5th generation must meet more and more stringent constraints: growth in the demand for spectrum resources, services with increasing requirements for high data rates and low latency, etc.

One of the possible approaches to respond to these constraints is to use multiple antennas (MIMO for Multiple Input Multiple Output) in a massive mode, the "massive MIMO", that is to say by the deployment of a very large number of antennas. These techniques are of increasing interest because they enhance the transmission capacity, as well as the robustness and the security level of communications, while reducing the complexity of the design.

In addition, 5G communications, which also include connected objects, must also face the challenge of the multiplicity of wireless transmission applications, whether in the industrial, medical, transportation or domestic sectors. Each of these applications corresponds to a particular transmission context, with the potential presence of interference.

The biggest challenge for 5G will be to make communications robust to interferences, whether intentional or not.

Hosting team: TELICE group from IEMN laboratory

The TELICE Group has a strong experimental, theoretical, and numerical expertise on the characterization, modeling and interference of the wireless propagation channel, ranging from low to very high frequencies (up to 300 GHz). As such, the group has developed a scientific equipment called MIMOSA [1] for the dynamic sounding of the multidimensional wireless channel in real time. Currently, it operates at 1.35 GHz in 16x16 MIMO mode with an 80 MHz band, and a funding request has been accepted to extend it to massive MIMO in the 3.5 GHz and 6 GHz bands. This equipment is unique in Europe in that it can also work in both sounding mode and communication mode. This flexibility offered by the MIMOSA architecture paves the way for several innovative and original research perspectives in the field of sensor networks, as well as in more traditional wireless networks, either for static or highly mobile scenarios.

Mission

The candidate will first study antenna selection strategies in massive MIMO to combat different types of interferences. Their goal is to determine which antennas should be chosen for transmission, while others are deactivated in order to optimize the overall energy efficiency. In this context, he will consider several antenna deployment configurations: distributed, localized or hybrid.

The candidate will then develop techniques for detecting the sources of interference in the network, based on channel sounding techniques that will be tested using the MIMOSA sounder.

The next step will consist in combining antenna selection techniques with appropriate power allocation methods in such a way to minimize the influence of interference sources on the transmission quality. The latter will be measured according to several possible metrics: SINR (Signal to Interference and Noise Ratio), total capacity, spectral or energy efficiency, required total transmission power, etc. This part of the study will allow the optimization of the topology of the Massive MIMO system, namely the positioning of the antennas and the number of antennas activated per node, according to the considered metrics. Joint techniques for antenna selection and transmit power distribution between active antennas will be designed to take into account the position and mobility of the terminals, as well as the interference source parameters obtained from the channel sounder.

Main assets of the post-doc

The originality of this subject is that it encompasses both theoretical aspects, with the development of new antenna selection and power allocation algorithms, and practical aspects, with the exploitation of the MIMOSA channel sounder. In addition, the candidate will rely on the group's strong expertise in the field of channel measurement, as well as on the latest research works realized by the supervising team on the impact of interferences on wireless communications and on power allocation [2-5].

Keywords

5G communication systems – Channel sounding – Massive MIMO – Antenna selection – Power allocation.

References

[1] P. Laly, "Sondeur de canal MIMO temps réel et applications", Thèse de l'Université de Lille1, 2016,

[2] V. Deniau, C. Gransart, G. L. Romero, E. P. Simon, J. Farah, "IEEE 802.11n Communications in the Presence of Frequency-Sweeping Interference Signals", IEEE Transactions on Electromagnetic Compatibility, 2017.

[3] A. Dermoune, E. P. Simon "Analysis of the maximum likelihood channel estimator for OFDM systems in the presence of unknown interference", EURASIP J. Adv. Signal Process., 2017

[4] J. Farah, E. Sfeir, C. Abdel Nour, C. Douillard, "New Resource Allocation Techniques for Base Station Power Reduction in Orthogonal and Non-Orthogonal Multiplexing Systems", IEEE International Conference on Communications (ICC 2017), May 2017, Paris, France.

[5] M.-J. Youssef, J. Farah, C. Abdel Nour, C. Douillard, "Waterfilling-based Resource Allocation Techniques in Downlink Non-Orthogonal Multiple Access (NOMA) with Single-User MIMO", the 22nd IEEE Symposium on Computers and Communications (ISCC2017), July 2017, Crete.

 

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