Current PhD projects in APNet


Henning Thomsen:
Title: Wireless Networking for Future Cellular Systems: Advanced Relaying and Massive Machine-to-Machine Communications

Supervisor: Petar Popovski

Start date: September 1,  2012

Henning Thomsen is pursuing the Ph.D. degree in wireless communications. His topic is in the area of machine to machine communication protocols, including their application in traditional cellular networks. He also studies heterogeneous networks, and rate-enhancing protocols for cellular networks using relays. He received the B.Sc. degree in mathematics, and the M.Sc. degree in applied mathematics, from Aalborg University, Denmark, in 2010 and 2012 respectively.


Germán Corrales Madueño:
Title: Massive Machine-to-Machine Communications

Supervisor: Petar Popovski

Start date: February 15, 2012

Germán Corrales Madueño obtained his M.Sc. in Mobile Communications from Aalborg University in 2011, where is currently pursuing his PhD in access protocols and reliability mechanism for Wireless Machine-to-Machine (M2M) communications in cellular networks. His interests include networking, wireless communications and its protocols.

Kasper Fløe Trillingsgaard
Title: Feedback Communication in the Finite Blocklength Regime

Supervisor: Petar Popovski

Start: September 1, 2013

With the increasing number of wireless devices and demand for higher data rates from traditional devices, the cellular infrastructure is becoming increasingly more complex. In particular, in streaming applications, it is a challenging problem to achieve high data rates and to fulfill tight latency constraints simultaneously. Also, the rising number of Machine-to-Machine (M2M)-type devices pose similar challenges, since their traffic pattern, with short packets that needs to be delivered very reliably, in general deviates significantly from what traditional wireless networks are designed for. Modern communication systems often feature a feedback link, which may be used for two-way communication or to enhance reliability; however such feedback links are typically only used for acknowledgements and are hence rarely fully utilized. This is due to established coding designs and approaches, as well as an early result by Shannon who found that the information theoretic capacity of a communication channel remain unchanged with feedback.
The project emanates from finite blocklength analysis – a topic within information theory that describes the trade-offs between packets lengths, achievable data rates and reliability of communication systems. It is investigated what the impact of finite blocklength analysis is on modern communication systems. In particular, how the results change the view on communication when feedback is present and how the theory may lead to novel techniques to optimize state of the art communication protocols. The expected outcomes of the project are insights and communication strategies that enhance modern communication systems consisting of devices with tight latency constraints or M2M devices by taking advantage of interaction among devices using feedback.


Pevand Bahramzy

Supervisor: Gert Frølund Pedersen

Start date: March 15, 2012

The design challenge posed by handset antennas is becoming more critical as network evolve to offer a wider range of services which require higher data rates, more frequency bands and in result more antennas. On top of that MIMO systems are now taking over traditional single link systems, which means additional antennas. Due to the fundamental limitation of antennas, the antenna system is a major obstacle in the implementation of successful multi-communication in small mobile devices. Therefore, new thinking and approaches are necessary to come up with antenna solutions that can fulfill the requirements of covering so many bands and still fit inside a mobile phone. So far, the development of RF and antenna has been separated, but Smart Antenna Front End (SAFE) (SAFE website link) is a project where we look at the antenna and RF as one integrated component that can be incorporated into all mobile communication equipment. SAFE project proposes to separate the Tx and Rx path all the way in the front end.
During my Ph.D., I will be developing efficient tunable narrow-band antennas based on MEMS tunable capacitor for the SAFE architecture. Some of the challenges that will be investigated are: antenna size, isolation between antennas, impedance stability and antenna efficiency.


Emil Feldborg Buskgaard
Title: User effect and dynamic tuning networks

Supervisor: Gert Frølund Pedersen

Start date: December 1, 2012

My PhD project is part of the Safe project (link to the Safe project site). This project uses antenna tuners to dynamically change the impedance match of the antenna in the phone. It is known that when the user is using the phone the head and hand are affecting the antenna impedance. If the phone can sense this mismatch then a feedback can be made to the antenna tuners to update the match and counteract the effect of the user.
My research areas are quantification of the user effect and topologies for tuning networks. The project starts by simulations and user studies of the user effect. A model will be developed that makes it possible to test different matching topologies. A major challenge is the measurement of S-parameters on a phone in the hand of a user. Normal S-parameter measurements are made through RF cables which both change the antenna performance of the phone and limit the freedom of movement of the user. A major part of this project will be the development of an S-parameter measurement setup that does not affect the antenna performance and allows the user to handle the phone more naturally.


Alexandru Tatomirescu
Title:Antenna for Compact MIMO Phones

Supervisor: Gert Frølund Pedersen

The radio transceiver in mobile phones is getting more complex because of the increased number of frequency bands that it has to cover. The SAFE(Smart Antenna Front End) project proposes an alternative architecture that employs separate antennas for the transmitting and receiving chain. An important part of the radio front end, duplex filter, is replaced by tunable filters and the isolation that can be achieved between separate Tx and Rx antennas. Thus, limiting the transfer of energy between the antennas becomes crucial for the communication link performance ( receiver sensitivity, non-linearity’s issues etc). Nevertheless, for today’s mobile phones, size is a serious constraint thus achieving the required electrical separation between the antennas is extremely challenging.
In other words, It is very difficult to make antennas to have different views of the wireless channel when they are close to each other and there is a strong electromagnetic interaction between them. The project aims at developing methods to isolate antennas even when they are electrically close.

Achuthan Paramanathan
Title: Green Mobile Clouds

Supervisor: Frank Fitzek

Start date: December 1, 2013

This project studies and investigates the concepts of Green Mobile Clouds. Green Mobile clouds are cooperative networks where network devices are connected directly to each other in an ad-hoc mesh network. A device involved in this network achieves higher performance in terms of throughput and energy saving incompare to the traditional WiFi network.
Using this concept, this project studies and investigates the possibility of optimizing the throughput of wireless mesh networks. The fundament for this investigation will be based on Inter-Flow Network Coding strategies implemented on top of CSMA/CA based Medium Access Control (MAC).


Àlex Oliveras Martinez
Title: Massive MIMO channel modeling based on COST 2100

Supervisor: Elisabeth De Carvalho

Start date - August 15th, 2014.
End date - August 14th, 2017.

Description: Massive MIMO is a new wireless communication technique where the transmitter and/or the receiver are provided with a very large number of antennas. The extra resources provided by these excess number of antennas is used to increase the capacity, reduce the probability of error and increase the energy efficiency. These improvements are only obtained in favorable propagation environments. My research is focused on finding the proper physical properties (aperture of the array, number of antennas, number and position of scatterers, etc.) that can benefit this technique. I am developing a channel model to represent and simulate the propagation characteristics of these channels. And I am searching for new scenarios where Massive MIMO could be deployed exploiting all its potential.


Nestor Hernandez

Supervisors: Prof. Frank Fitzek, Associate Prof. Daniel Lucani, Dr. Janus Heide (Steinwurf)

Start - September 1st, 2013
End - August 31st, 2016

With Steinwurf / AAU ESR (Early Stage Researcher) for the Crossfire (Marie Curie Initial Training Network) Project:
Job description: My work focuses on evaluating Network Coding based techniques for improving the throughput and energy of cooperative networks in LTE-Advanced heterogeneous networks.


Miyu Momoda

Supervisors: Prof. Petar Popovski and Dr. Čedomir Stefanović

Start - 1/10/2014
End – 30/9 -2017

Project: ADVANTAGE (Advanced Communications and Information processing in smart grid systems) -
Project/job description:
My research topic is Reliable Wireless Communications of Microgrids.
Microgrid is a small portion of a power grid designed to utilize the distributed energy resources and electrical loads that can be operated in a well controlled and coordinated way with or without a connection to a main grid. Communication technologies play an important role in Microgrids in order to effectively and reliably operate the whole power grid.


Marko Angjelichinoski

Supervisors: Prof. Petar Popovski and Dr. Cedomir Stefanovic

Start - 1/10/2014
End – 30/9 -2017

Project: EU-FP7 Advanced Communications and Information Processing for Smart Grid Systems (ADVANTAGE),
Project/job description:
I obtained my BSc and MSc degrees at the Ss. Cyril and Methodius University in Skopje, Macedonia. My research interests are in the area of statistical signal processing in communication systems, estimation, detection theory and nowadays, Smart Grid systems. Currently, I am PhD Fellow at the Aalborg University where I work on designing advanced coordination and control strategies for MicroGrids that operate using the existing power line equipment and provide robust communication capabilities without relying on external communication infrastructure.