Communication and Signal Processing

• Beyond 5G and 6G Systems: The first generation (1G) cellular systems was a public extension of cordless telephony, based on an adaptation of analog trunk radios. The second generation (2G) introduced digitalisation and data compression, while the third (3G) was the first to feature purpose-built PHY and MAC technologies to support large numbers of users and provide voice and data services over cellular infrastructures at affordable cost to the general population. The fourth generation (4G) “longterm evolution” (LTE) system surpassed the full range of data services previously offered by cable networks. The most recent, fifth generation (5G) system was designed to provide a larger degree of flexibility in terms of data rate, latency, penetration, user capacity and link quality, enabling high-speed wireless internet, among other things. We are developing advanced variations of 5G and the upcoming 6G systems, which will incorporate several advanced solutions such as full-duplex radio, non-orthogonal multiple access, rate-splitting multiple access, and sub-THz transmission. 
• V2X Communications: Current wireless-based systems serve people primarily through their smartphones. A large portion, if not the majority, of future wireless traffic will comprise vehicles, due to autonomous connected driving and/or communications being routed by vehicles, as there is a trend towards small and moving cell architectures. This paradigm of vehicle-to-anything (V2X) communications requires training advanced technologies such as full-duplex radio, non-orthogonal multiple access, and rate-splitting multiple access, to fast time-varying channels. Our research group is actively investigating this topic. 
• Wireless Localization and Awareness: The recent expansion of wireless localization services, initially possible only via (GPS), to mobile (cellular) and even personal (WiFi, Bluetooth and UWB) systems, has greatly enriched the experience of users and made wireless connectivity an essential tool of modern life. Still, the accuracy of current navigation systems is too poor to enable autonomous driving; 3D tracking in industrial environments is still unreliable; and consumer-friendly indoor localization services are not adequate. With a long track-record in the area, which includes a successful start-up (see https://zigpos.com), our research group continues to push the boundaries of wireless localization technologies towards the more general concept of wireless awareness systems.
• Physical-layer Wireless Security: As the world becomes more connected and automated, we are increasingly exposed to cybersecurity threats. While a person today may interact daily with a few wireless devices (a laptop, a mobile phone, perhaps a smart watch), in the future people will use dozens of devices (wearables, ambient sensors, vehicles), sometimes unknowingly. All of these devices will be autonomous and wirelessly discoverable. This scenario renders current high-layer security protocols impractical, requiring new mechanisms that rely on physical-layer features to provide data security. Our group develops algorithms and hardware that provide seamless end-to-end security.

• Two PhD candidates graduated, both Summa Cum Laude: Dr. Stoica (now with Lenovo Research, Germany) and Dr. Iimori (now with Ericsson Research, Japan);
•  In 2022, Prof. Abreu became an Associated Editor of the journals IEEE Signal Processing Letters and the IEEE Wireless Communication Letters, after serving a five-year term as Executive Editor of IEEE Transactions on Wireless Communications (2017 to 2021); 
• Led a large industrial project, with the group producing 14 patents.

During the period 2019-2022, the Wireless Communications and Signal Processing group included six PhD students, supported by an industrial project sponsored by Continental AG and the EU-Japan project ORACLE, which was sponsored jointly by the BMBF and the JSP.

• Hyeon Seok Rou, Hiroki Iimori, Giuseppe Abreu, David González G., and Osvaldo Gonsa: “Scalable Quadrature Spatial Modulation,” IEEE Transactions on Wireless Communications, Aug. 2022. 
• Omid Taghizadeh, Tianyu Yang, Hiroki Iimori, Giuseppe Abreu, Ali Cirik, and Rudolf Mathar: “Quantization-Aided Secrecy: FD C-RAN Communications with Untrusted Radios,” IEEE Trans. on Wireless Communications, Apr. 2022. 
• Liming Hou, Feng Lian, Shuncheng Tan, Cong’an Xu and Giuseppe Abreu: “Robust Generalized Labeled Multi-Bernoulli Filter for Multitarget Tracking with Unknown Non-stationary Heavytailed Measurement Noise,” IEEE Access, vol 9, Jul. 2021. 
• Naoya Hirosawa, Hiroki Iimori, Koji Ishibashi and Giuseppe Abreu: “Minimizing Age of Information in Energy Harvesting Wireless Sensor Networks”, IEEE Access, Nov. 2020. 
• Razvan-Andrei Stoica, Giuseppe Abreu, Takanori Hara and Koji Ishibashi: “Massively Concurrent Non-orthogonal Multiple Access for 5G Networks and Beyond”, IEEE Access, Jun. 2019