Wireless Communication Technologies and Signal Processing This work addresses the fundamental technologies required for developing the radio components of next generation 6G wireless communications for public or private networks, systems, its coexistence with existing technologies, as well as promoting easier deployment and migration from older RAN technologies. Focus is on: Terahertz Communications and Ultra-Massive MIMO: Development of technologies and systems enabling Terabit-per-second (Tbps) wireless communications needed to support long term exponential capacity increase of mobile communication networks. Piggybacking on H2020 results in THz communication, the work further explores technologies above 100GHz with focus on channel measurements, modelling, and sounding strategies, as well physical layer, and signal processing techniques and, notably, waveform design. Due to the shorter wavelength, many antennas can be packed in a small area thus, leading to the concepts of mMIMO and ultra mMIMO which require further investigation. Meta-surfaces to control propagation are in scope as well as work in the computing domain to deal with the massive amount of processing needs of Terahertz communications. Technologies to change propagation characteristics of wireless channels, e.g. through intelligent reflecting surfaces (IRS) or large intelligent surfaces (LIS) are also in scope to enable the replacement of the current cell-/ network-centric approach by a user-centric one where the cluster serving a particular UE can be determined dynamically with realisation of a cell-free mMIMO and uniform services across the network can be offered. Joint communication and sensing: Communication work is complemented by work in the field of location and sensing capabilities for devices. It includes joint radar and communications, with signal processing techniques for wideband beamforming, or spatial multiplexing, as well as transceivers for higher spectral efficiencies, better power efficiency, faster data converters, high density digital logic, chip-package-antenna co-design, and combination of silicon technologies with III-V technologies. Waveform design can extend to the radar domain to offer the potential for combined radar and communications capabilities. Experimental prototypes are in scope. New Waveforms, Random and Multiple Access: Support scalability of future Machine Type Communication with massive number of connected devices transmitting very sporadic data, with minimum protocol overhead and energy consumption. While strategies relying in the CP-OFDM (cyclic-prefix OFDM) waveforms have been adopted in 4G and 5G, other waveforms (e.g. FBMC, GFDM) allow to relax the strict synchronization and orthogonality conditions of OFDM and, by doing so, increase the spectral containment of 6G systems. Besides other promising multiple-access schemes may also be considered such as Non-Orthogonal Multiple Access (NOMA) or Rate-Splitting Multiple Access (RSMA) to enable grant-free access, or other novel promising directions with potential for adoption at standardisation level (considering not only dense cell but also sparse cell coverage). Enhanced Modulation and Coding: Support to innovative channel coding approaches towards “error free” channel transmission. It should solve current bottlenecks in implementation issues such as computational complexity, algorithm parallelisation, chip area, energy efficiency, etc. whilst supporting hundreds of Gigabits per second and low latency. It is compatible with Increasingly massive MIMO-implementations and contribute to the future modulation and coding schemes, possibly mixing data-driven and model-driven approaches, as required for 6G, retaining reliable, energy-efficient characteristics. Wireless Edge Caching: Support the capability to deliver Terabytes per month for all in a scalable and cost-effective manner. Focus is on the information theoretic foundations, in the coding and signal processing algorithms, and in the wireless network architecture design, to exploit the potential gain of content-awareness. It covers technologies exploiting edge caching in areas as Coding (e.g. combining edge caching with modern multiuser MIMO physical layer schemes), Protocol architectures (e.g. combining edge caching with video quality adaptation); and AI/ML based content popularity estimation and prediction, to efficiently update the cached content. Potential vertical-specific developments may be considered as well.Human-friendly Radio systems: Support innovative antenna and physical layer technology for higher acceptability of radio infrastructures by citizens. It covers new antennas and new antenna systems, that need to visually blend seamlessly in the urban landscape through use of new designs or new materials, in the context of an increased density of base stations and more complex antennas to support higher frequency ranges. It also covers antenna systems for EMF control and awareness to minimise human exposure. The target antenna work should account for mMIMO and address the limitation of linear increase of the number of antennas to overcome the much higher path loss in THz-band. Spectrum Re-farming and Reutilisation: Support future high bandwidth demand and versatile spectrum usage requirements by multiplicity of applications through optimised spectrum management, sharing and dynamic application aware allocation. It covers spectrum reutilisation between RAT’s, including NTN access, and addresses new THz spectrum. Novel approaches with use of AI/ML technology for real-time spectrum efficiency is in scope. It also covers specific sharing scenarios for unlicensed spectrum use, and fundamental work on these challenges for new terahertz bands will also be needed. Proposals may address one or more of the topics above.