Digital transmission group (DTG) focuses its activities on signal and system models, wave-forms, and signal processing algorithms for digital communications. The work has both communication theoretic aspect where the goal is to optimize the system performance at link or radio access system level, as well as the implementation aspect where the target is to de-velop technologies for highly integrated and highly configurable terminals/modems. The group has studied OFDM signal processing techniques for digital TV (DVB-T, DVB-H, DVB-T2, DVB-NGH) since early 1990’ies. It has also developed filter bank based multicarrier systems and other applications of filter banks in communications signal processing, with strong emphasis on spectrum sensing and cognitive radio in the recent years. Along the years, the implementation-oriented studies have included all-digital synchronization techniques and multirate signal processing methods for flexible communication receivers and transmitters, i.e., software defined radio. Since late 1990’s, DSP-enhanced radio has been an important focus area. Here the idea is to mitigate the effects of inevitable imperfections of the analog RF stages of transmitters and receivers through advanced digital calibration and signal processing techniques. The specific topics here include I/Q-imbalance compensation and mirror-frequency rejection, compensation of intermodulation distortion of receiver small signal components’ (mixers, LNA’s, etc.) nonlinearities, estimation and mitigation of RF oscillator phase noise, different linearization methods for transmitter power amplifier, and modeling and reduction of imperfections of sampling and analog-digital interface. Furthermore, recent work includes also extensions of classical information theory (capacity laws by Shannon, Hartley, et al) to cover the effects of above mentioned transmitter and receiver imperfections. In addition to communications, the group has addressed signal processing issues in navigation and positioning systems, considering topics like CDMA signal processing algorithms for GPS and Galileo systems and mobile network based positioning. The group is led jointly by Prof. Markku Renfors and Prof. Mikko Valkama. The mobile positioning activities are led by Senior Research Fellow Elena-Simona Lohan. There are 2 post-docs, one lecturer and 18 active Ph.D. students in the group. Additionally, there are typically several visiting Ph.D. students and about 5 research assistants and other M.Sc. students preparing their thesis under the supervision of the senior researchers of the group.