Sustainable Communication Networks

  • The ComNets Team

    Staff and student workers

  • July 2023

    Visit by Cameroonian guest scientists

  • June 2023

    Researchers from Sri Lanka visiting ComNets

  • June 2023

    Guest students from Sri Lanka doing a research internship

  • April 2023

    Presentation of Cameroonian guest scientist at HWK Delmenhorst

  • March 2023

    Joint Retreat between ComNets Bremen and ComNets Technical University Hamburg-Harburg

  • June 2022

    Int. Workshop "Advanced ICT for Tropical Medici"

  • November 2023

    Colleagues listen to a presentation



The main research focus of the Sustainable Communication Networks group at the University of Bremen is design and performance analysis of communication networks and their protocols. This includes the implementation of prototypes as well as performance studies by mathematical analysis and simulation. The main keywords are: sensor networks, opportunistic networks, future internet. An important aspect across all reseach projects is sustainability in a two-fold aspect, i.e. how communication networks can enhance the sustainability of networking applications, and how the network itself can be designed in a sustainable way. Research projects are mainly funded by national and international government institutions.

The group consists of several post-docs as well as fully employed research assistants working on research projects and their doctoral thesis. Additionally there is a small technical and assisting team and many students working as student workers or doing their thesis.


ComNets on Social Media

Prof. Anna Förster has a new blog to share her educational and research experiences, check it out here:

Our X (former Twitter) channel is here:

You can now also follow us on Mastodon

Contacting Prof. Anna Förster

Office hour

In general, every Thursday, 14-15, online. You can find the next available slots and the Zoom link directly in this Google calendar (requires Google account). You don't need to register for the meeting; enter the Zoom meeting and wait for your turn in the waiting room until you are admitted to the call. Depending on the number of students calling, this might take some time.

In urgent matters, write an email.


Our work on evaluating Reflexive Forwarding for ICNs was accepted at IEEE SmartNets'24

eflexive Forwarding (RF) is a draft standard being discussed at the IETF for Information Centric Networks (ICN). The Internet of Things (IoT) produces and consumes vast amounts of data, positioning it as an optimal choice for harnessing the power of information-centric networks. However, the pull-type communication paradigm, a primary architectural pillar of ICNs, must be adapted to handle push-type communications prevalent in the IoT. RF provides the mechanisms to enable an information-centric IoT. In our research, we asked the question, "Reflexive Forwarding: Way Forward for Communications in an Information-centric IoT?" and attempted to find an answer by modeling and simulating a large-scale IoT using ICNs as the primary communication architecture. The findings of this work were accepted to be presented at the IEEE SmartNets'24 conference in Washington, D.C., U.S.A., at the end of May 2024.

The winners: Julia Twachtmann, Bror Giesenbauer, Anna Förster, Detta Sophie Schütz, Guido Schmiemann (from left)
The winners: Julia Twachtmann, Bror Giesenbauer, Anna Förster, Detta Sophie Schütz, Guido Schmiemann (from left)

Receiving the "The Golden Plietsch" award

Professor Anna Förster won the "The Golden Plietsch" award, which is endowed with 7,000 euros for the student project "MoleNet: Underground Sensor Networks for the Sustainable Development Goals". Every year, the "The Golden Plietsch" prize is awarded by the University of Bremen Foundation and its sheltered foundations to honor ideas for more sustainability and positive urban development in Bremen.


Publishing of “The Opportunistic Zoo”

Our paper, dubbed “The Opportunistic Zoo”, is finally out! Congratulations to all co-authors for years (literally) of efforts and time!

October 2023

Distributed Adaptive CPM Generation Control Approach to Minimize the Channel Load in VANETs

Akhil Simha Neela successfully defended his research on modeling and evaluating the performance of a distributed adaptive algorithm for generating collective perception messages (CPM) in VANETs to reduce channel load in communications. He used the Artery model framework to implement his extensions and to evaluate the performance, which included the use of the CN+ and the LuST trace. The abstract of her work is given below.

We congratulate him on his success and wish him the best in the future.


In recent years, the growing number of vehicles on the road has led to a significant trend toward increasing the autonomy of vehicles. This surge in vehicle autonomy has made ensuring safety and minimizing traffic congestion a top priority. In response to these challenges, Collective Perception (CP) services have been introduced within Vehicular ad-hoc networks (VANETs). CP services enhance safety by enabling vehicles to be aware of their surroundings, detecting both Vehicle-to-Everything (V2X) and non-V2X-enabled entities. Vehicles detect nearby objects and generate Cooperative Perception Messages (CPM), which are exchanged with other vehicles, creating a collective awareness of the environment. This collective awareness empowers vehicles to make informed decisions based on various scenarios.

The proposed ETSI CPM Standard limits the message generation between 1 Hz and 10 Hz to avoid channel overload within this bandwidth. This research focuses on developing algorithms to determine the optimal generation frequency for CPMs generated by individual vehicles. The primary objective is to enable vehicles to autonomously determine the best transmission frequency, facilitating distributed adaptive message generation. Various mechanisms have been implemented using the Artery V2X Framework Simulation Model to achieve this goal.

This research explores the critical intersection of autonomous vehicles, collective perception, and adaptive message generation, aiming to enhance safety and efficiency in modern road networks.

September 2023

Completion of Internet of Things Course (SoSe 2023)

The ComNets block course on teaching the Internet of Things was completed successfully on the 22nd of September. The course consisted of lectures, labs, problem-based learning sessions, poster sessions, and projects focusing on different technologies used in the IoT.

90 students registered for the course, but we had to shortlist to select 26 students due to resource limitations in conducting such a course. In the course, we provide all the IoT hardware the students require to perform the different tasks. They were only required to bring their own laptop.

The course's final task is a project, where the students work on finding a solution to a given problem. The following three problems were offered this time.

- Theft Protection - Develop a solution to prevent the theft of deployed IoT devices
- Dog Collar - Develop a virtual dog leash using the LoRa wireless technology
- Smart Parking - Develop a comprehensive parking solution for a closed parking lot

In addition to the given projects, students were also allowed to propose their own projects. One proposed project was the IoT solution to monitor appliance usage in student hostels. The students' solutions were evaluated for their originality, reliability, conciseness, and knowledgeability, including selecting the best project. The student group with the best project won an award.

The pictures show a selection of the students and their work, including the best project winners.


Completion of the NetSys'23 Conference in Potsdam, Germany

The biennial NetSys'23 conference was completed successfully on the 7th of September at the HPI in Potsdam, hosted by the University of Potsdam. The conference hosted several tutorials, workshops, keynotes, research presentations, and live demos related to networks and distributed systems. It was well participated and included foreign participants in addition to the Germany-based participants. ComNets was represented by Anna Förster, Asanga Udugama, Shadi Attarha, and Thenuka Karunatilake.

Shown are some photos of the participants. The conference website is at

Picture of the lab preparation in progress.
Picture of the lab preparation in progress.

Internet of Things Course Preparation (SoSe 2023, Block Course)

ComNets will conduct the Internet of Things (IoT) block course in September, the 8th iteration since 2016. As usual, many interesting topics are taught in this course, ranging from different microcontroller platforms to application scenarios.

All topics are refreshed every year to accommodate current technologies used. One of the main changes this year is using ESP32-based microcontrollers in the Arduino lab. Instead of the ATMEL platform we used previously, we want to emphasize how the same microcontroller platform can be used with different development environments. We also introduced the BME280 sensor for students to write code in the lab to collect multiple environmental data to analyze and present in a report.

NetSys'23 Involvement of ComNets

NetSys is a conference every two years, bringing together engineers and scientists from academia, industry, and government. Its primary focus is facilitating discussions about the latest advancements in networks and distributed systems.

The upcoming NetSys conference, named NetSys'23, is hosted by Hasso-Plattner-Institut in Potsdam, Germany. The event is scheduled from the 4th to the 7th of September. ComNets plays a significant role in the organization of NetSys'23. Anna Förster is a co-chair of the technical program committee (TPC), while Asanga Udugama is the conference's web chair. Additionally, two other members of ComNets, namely Shadi Attahara and Thenuka Karunatilake, are slated to showcase their research. Shadi Attahara will present her work on the Fault Detection Framework for Trustworthy Provisioning of Sustainable IoT Applications, while Thenuka Karunatilake will delve into Collective Perception Messages in VANETs.

August 2023

Completion of Combined Mester Theses on Implementing Content-Centric Networking for the Internet of Things

Sowmia Suresh Kumar and Yamani Dalpathadu successfully defended their combined work on implementing and evaluating Content-Centric Networking (CCN) for the Internet of Things (IoT). Sowmia focussed on implementing CCN for the Internet, while Yamani focussed on the Sensor Network side. The implementations were specifically for resource-restricted devices, using Python and Micro-Python as the development language. In addition to presenting the implementation details and the performance evaluation, they also demonstrated the complete system in operation using WiFi and Ethernet for communications in the Internet and LoRa on the sensor network side. The titles and the abstracts are given below.

We congratulate them on their success and wish them good luck for their futures.


The Internet of Things (IoT) Enabled Content-Centric Networking (CCN) for the Internet

Student: Sowmia Suresh Kumar

A pull-type communication technique is used in content-centric networking, where information flow only happens in response to requests. The IoT is perfectly suited to employ CCN for communications since it is largely an information-carrying network. IoT devices, such as sensors, can communicate with the Internet to exchange data for various purposes. Due to resource limits, pull-type communications are regarded as inappropriate for IoT devices. This thesis study suggests push-type techniques for publish-subscribe-based applications to avoid pointless data transmissions. The goal here is to create a hardware setup that supports CCN-based Internet and assess the effectiveness of the system that has been put in place to support various IoT use cases. To assess the deployed system, the IoT network's operations, including the gateway that manages both the Internet and the IoT sides, are simulated. The entire system is made up of Python3-programmed hardware elements like Raspberry Pi. The effectiveness of the developed CCN-enabled Internet infrastructure was tested through several experiments using an application for a smart university environment monitoring system. With a content delivery ratio of 1.0, the findings demonstrated excellent network content retrieval efficiency. Content retrieval improved via in-network caching in intermediate CCN routers, and no packet losses were noticed. The Reflexive Forwarding extension maximized content delivery for periodic content retrieval scenarios. Better caching policies are needed since network caches send some users outdated content. To stop subscribers from accessing cached data from routers, the gateway issued a particular Record ID. Recommendations on improvements and features that may be added to the system to make it more useful, such as mobility and intelligent automobile systems, could be considered for future work. Security features like content encryption could be required to avoid cache poisoning, which was not covered in this thesis work.

Content-Centric Networking (CCN) based Internet of Things (IoT) with Long Range (LoRa) Communications

Student: Yamani Dalpathadu

The Internet of Things (IoT) is a transformative concept that expands the capabilities of the Internet by incorporating a diverse range of devices into its ecosystem. The presence of various sensors and actuators characterizes the IoT. Information-Centric Networking (ICN) is an emerging networking paradigm that aims to shift the paradigm of Information-Centric Networking. The main paradigm in ICN is that it considers content caching. In-network caching enables the ICN to gain huge performance advantages by caching content. Due to the resource limitations inevitable in IoT networks, push-type communication has to be focused on. Reflexive Forwarding for CCN is an extension of CCN that can handle complex data flow scenarios, and this protocol can be used to effectively exchange data between CCN-enabled IoT and CCN-enabled Internet networks. The proposed setup was implemented on a hardware test bed. The performance evaluation of the proposed setup has been conducted using different use-case scenarios that can be categorized as either a publish/subscribe or query/response type of event. The results showed that the utilization of in-networking caching proved efficient, but it was observed that it facilitated the expedited retrieval of content. The use of Record-ID always made sure that subscribers always received fresh data. Overall, using Reflexive Forwarding for CCN was shown to be very beneficial for data communications in the system.

Publishing of “The Opportunistic Zoo”

Our paper, dubbed “The Opportunistic Zoo”, is finally out! Congratulations to all co-authors for years (literally) of efforts and time!

July 2023

Implementation of ContikiMac Protocol on OMNeT++ with FLoRa

Uzmasaman Aejaz Chanderki successfully defended her research on modeling and evaluating the performance of the ContikiMac protocol in LoRa. She used the FLoRa model framework of OMNeT++ to implement the ContikiMac. The abstract of her work is given below.

We congratulate her on her success and wish her the best for her future.



This thesis focuses on the implementation of the ContikiMAC protocol on the OMNeT++ simulation tool’s FLoRA framework. This framework enables precise modeling and evaluation of the proposed implementation and provides vital insights into the behavior and performance characteristics of the ContikiMAC protocol. The thesis aims to investigate the acceptability and efficacy of the ContikiMAC protocol on LoRa-based networks in terms of duty cycle and packet delivery ratio. In this thesis, the implemented ContikiMAC protocol is designed to cohabit with the existing LoRaMAC protocol, which is the default MAC protocol for FLoRa. A performance evaluation of the ContikiMAC protocol is carried out in this thesis with variations in node sleeping time and a variable number of packets to compare it against the hardware implementation of the ContikiMAC protocol on a PyCom device, which is carried out by the authors of LoRaDucy [1]. With this implementation of the ContikiMAC protocol on FLoRA, further research can be done in the future to compare and evaluate it against the existing MAC protocols.

June 2023

Students from Sri Lanka doing Research Internship

Four Bachelor students from Sri Lanka visited the ComNets department for a research internship as a part of their final year's project. They developed a sensor network prototype based on MoleNet and prepared a field study in a rubber plantation in Sri Lanka.

April 2023

Girls Day 2023

In diesem Jahr organisierte ComNets im Rahmen des Girls' Day eine einzigartige Veranstaltung, um Kreativität zu inspirieren und Innovation zu fördern, die Technologie mit der Kunst verband. An diesem Tag führten wir die Schülerinnen in die Welt der Chibitronics-Schaltungen ein und ermöglichten es ihnen, intelligente Postkarten zu gestalten, die sowohl ihre technischen Fähigkeiten als auch ihre künstlerischen Talente zur Schau stellten.

Die Schülerinnen lernten, wie sie Chibitronics-Komponenten wie LEDs, Sensoren und leitfähiges Klebeband verwenden können. Diese Komponenten wurden in einer Vielzahl von Farben zur Verfügung gestellt, was den Schülerinnen die Freiheit gab, ihren Postkarten eine lebendige Farbpalette zu verleihen. ComNets freut sich auf weitere solche innovative Veranstaltungen, die unsere Schülerinnen dazu befähigen, die grenzenlosen Möglichkeiten der Verschmelzung von Wissenschaft, Technologie und Kunst zu erkunden.

November 2022

New Seminar Series "Connect-Them-All"

In the upcoming talk of the connect-them-all seminar, Dr. Dirk Pesch will talk about Low Power Wide-Area Wireless Internet of Things with LoRaWAN.

Date: January 05, 2023

Live stream:

For further details please visit the website:

Please subscribe to our newsletter for regular update about the Seminar:


Prof. Dr. Anna Förster | Comnets, University of Bremen -

Dr. Marco Zennaro |  Science, Technology and Innovation Unit,  The Abdus Salam International Centre for Theoretical Physics -

Prof. Dr. Pietro Manzoni | Department of Computer Engineering, Universitat Politècnica de València -

Dr. Fredrik Ahlgren | Faculty of Technology, Linnæus University -

October 2022

New Lecture "Grundlagen der Informationstechnik"

With the winter semester 2022/23, we have started a new lecture "Grundlagen der Informationstechnik" (Foundations of Information Technology) for Bachelor students in Electrical Engineering and related programs. More information is available here.

September 2022

New Project "Smart Farming Made Simple"

We have launched a new project named "Smart Farming Made Simple" which aims at the development of low-cost, self-configuring sensor and actuator nodes for smart agriculture. More details are available here.

May 2022

New technologies for more efficient tropical medicine" is a new joint DAAD project between
ComNets and Mahidol University in Bangkok.

Read more about this exciting project here:

November 2021: Best paper award for our PhD student Gibson Kimutai

Best paper award at IEEE GHTC Conference for our PhD student Gibson Kimutai

Our PhD student Gibson Kimutai (in cooperation with the University of Rwanda and Moi University, Kenya) has won the best paper award at the IEEE Global Humanitarian Conference - congratulations! He is working on bringing the Internet of Things and Machine Learning to Tea factories in developing countries and his results can be easily transferred to other industrial processes. Check out his talk here:


His papers are available here:


1.7.2021: IoT Innovation Project starts


Recognising and repelling wolves with an intelligent fence

Our project “mAInZaun: Modular and AI assisted Intelligent Fence for Protecting Domestic Animals” has received financing from the Federal Ministry of Food and Agriculture (BMEL) and is now running from beginning of July 2021 until end of June 2024. Together with the University of Giessen and RoFlex GmbH, we will design, develop and prototype an intelligent fence, which is able to reliably recognise approaching wolves and to scare them off by using light, ultrasound, moving elements, scent marks, etc. One unique property of our system will be the recognition of individual wolves and the personalisation of the repellant methods applied to avoid habituation, a common problem with other wolf repellants. More information about this project can be found on the dedicated website: A press release (in German) is available here:

General Studies Seminar "Aspects of Sustainability"

In the seminar "Aspects of Sustainability" we will learn about the different and sometimes contradictory aspects of sustainability by viewing various documentary films (English with German subtitles) and have a discussion after each film. The seminar is part of the General Studies and open for all university members. The seminar starts on Thursday, 25th October at 18:00 hrs in lecture hall H2. More information is available here.

Presentation in Ruzena Bajcsy Lectures on Communications

The head of the Sustainable Communication Networks Department, Prof. Anna Förster, gave a presentation titled "Organic Data Dissemination in Opportunistic Networks" in the context of the lecture series "Ruzena Bajcsy Lectures on Communications" at University of Darmstadt, Germany. A summary of the event can be found here.

ComNets goes to space!

Just a couple of days ago, ComNets became partner in the European Space Agency Topical Team on Tissue Healing in Space, where it will contribute to the communication and data analysis system for innovative sensor devices.

kids4mint - ran an die Elektrotechnik!

Gerade ist die erste kids4mint Kinder-Sommerschule erfolgreich abgeschlossen! Wir hatten viel Spass, gutes Wetter und tolle Experimente zusammen gemacht. 12 Kinder im Alter von 10 bis 12 Jahren haben Motoren gebastelt, elektrotechnische Schaltungen kennengelernt und kleine Maschinen gebastelt. 

Nächstes Jahr im Sommer geht es weiter - also sofort auf die Mailing Liste setzen und gespannt bleiben!


Kinder beim Basteln
Kind hält ein Modellflugzeug in der Hand
Kinder führen einen Physik-Versuch durch
Kinder spielen im Freien
Ein Modellfahrzeug
Kinder beim Basteln

PhD student of ComNets develops miner location system

In cooperation with the Wits mining institute in South Africa, a PhD student of the ComNets department, Idrees Zaman, is working on a system which assists miners by providing information about possible threats and supporting rescue staff to locate miners who have become lost in case of a disaster. The system is based on a wireless underground sensor network which is under development at the ComNets department. There is an article about the project in the South African newspaper "Sowetan" and a video by Wits university available on Youtube.

We are member of the high-profile area Minds, Media, Machines

ComNets has become a member of the the high-profile area Minds, Media, Machines which is a cooperation between researchers of different disciplines in the topic of intelligence, cognition in autonomous agents and teams of agents in the context of mediatized worlds. More information is available under this link.

Paper about teaching Internet of Things published

We have published a paper about the concept and evaluation of our Internet of Things lecture. Details about the paper can be found here.

Prof. Förster's TEDxTUHH talk now available online

Prof. Förster gave a talk with the topic "Gossiping in digital communication networks" in the 2015 TEDxTUHH event in Hamburg. The video of the talk is now available online

“Introduction to Wireless Sensor Networks” by Anna Förster

The book “Introduction to Wireless Sensor Networks” by Anna Förster has been published by Wiley and IEEE Press and is currently already available as an online version and very soon also as a hard-copy (July 2016). The online companion with slides, further information and links for purchasing is here. Comments are highly welcome!

Vortrag "Entscheidungsprozesse in Kommunikationsnetzen: Naturinspirierte Verfahren"

Im Rahmen der Ringvorlesung "Universelle Eigenschaften des Entscheidens" hält Frau Prof. Anna Förster am 11. Mai einen Vortrag zum Thema "Entscheidungsprozesse in Kommunikationsnetzen: Naturinspirierte Verfahren".


Nicht nur wir Menschen stehen ständig vor Entscheidungen, sondern auch unsere Geräte. Vor allem unsere heiss geliebten Computer stehen andauernd vor Entscheidungen, wie und wann sie welche Informationen wohin senden. Wenn ich einer Freundin eine Email schicke, gebe ich einfach eine Adresse ein. Aber wie kommt meine Email von meinem Rechner zum Rechner meiner Freundin? Findet die Email auch wirklich den kürzesten Weg dahin?

In diesem Vortrag werden wir eine Reihe von Entscheidungsprozessen für Computer & Co kennenlernen. Und zwar nicht die einfachen, trivialen Prozesse, sondern die naturinspirierten und intelligenten Prozesse. Was hat eine Ameise damit zu tun? Oder ein Vogelschwarm? Oder ein Baum? Das werden wir gemeinsam erkunden.


Der Vortrag findet statt am Mittwoch, 11. Mai, von 16 bis 18 Uhr in der Rotunde im Cartesium, Enrique-Schmidt-Str. 5, 28359 Bremen.

Talk: Pervasive Systems at a Glance

The Department of Sustainable Communication Networks had the pleasure to welcome Prof. Paul Havinga and Prof. Nirvana Meratnia from the University of Twente, Netherlands, for a Talk on Pervasive Systems.

Abstract: In this presentation, we will provide a short overview of core research themes and their related recent projects of the Pervasive Systems group. The common areas of research within Pervasive Systems are opportunistic sensing and wireless networking and  sensor data analytics. We will also show how major research and development challenges such as energy-efficienty, reliability, robustness, and accuracy, faced in these themes have been addressed and how the research results have been integrated through addressing practical deployment and development issues in real-world applications.


Prof. Paul Havinga is full professor and chair of the Pervasive Systems research group at the Computer Science department at the University of Twente in the Netherlands. He received in 2000 the 'DOW Dissertation Energy Award' for his Phd thesis. He has a broad background in various aspects of communication systems, including wireless communication, sensor networks, smart sensor systems, Cyber Physical Systems, QoS over wireless networks, reconfigurable computing, and on interconnection architectures for multiprocessor systems. The common themes in his area of research is the development of large-scale, heterogeneous, wireless, distributed systems. Research questions cover architectures, protocols, programming paradigms, algorithms, and applications. He has a significant experience as project manager in several national and international research projects on wireless sensor networks. In 2001 he initiated the first European project on wireless sensor networks EYES, and many national and international projects evolved from this. In May 2007 he received the ICT Innovation Award for the successful transfer of knowledge from university to industrial use. In June 2007 he received the "van den Kroonenberg award" for being a successful innovative entrepreneur.  


Dr. Nirvana Meratnia is associate professor in the Pervasive Systems Group at the University of Twente. Her research interests are in the area of Internet of Things (IoT), distributed sensor data analytics, (underwater) wireless sensor networks, and wearable/implantable communication and computing. The common themes in her area of research are energy-efficient, accurate, and reliable sensor data processing, reasoning, and interpretation. This goes hand in hand with requirements and limitations posed by the wireless communication being in air, in body, or underwater. This in turn requires a cross-layer optimization. She is and has been involved in many EU and national projects related to these themes.