Talk
Future Development of IMT Systems
Prof. Sergo Shavgulidze, Georgian Technical University, Georgia

World Radiocommunication Conference has adopted RESOLUTION COM6/20 (WRC-15, Geneva 2015) concerning the studies on frequency-related matters for International Mobile Telecommunications (IMT) identification including possible additional allocations to the mobile services on a primary basis in portion(s) of the frequency range between 24.25 and 86 GHz for the future development of International Mobile Telecommunications for 2020 and beyond.
According to RECOMMENDATION 207 “Future IMT systems” WRC-15 recommends to invite ITU-R to study as necessary technical, operational and spectrum related issues to meet the objectives of future development of IMT systems.
In our presentation first we consider enhancement of key capabilities from IMT-Advanced to IMT-2020 and then present the technology trends that will make possible such enhancement. The subgroup of such technologies is technologies to enhance the radio interface and enabling higher data rates, such as advanced waveforms, new spectral and energy efficient modulation and coding  schemes,  new multiple access schemes,  advanced antenna technologies (3D-beamforming,  active antenna system, massive MIMO, network MIMO, spatial modulation).
We briefly consider some new techniques, such as filtered-OFDM, filter bank multicarrier, orthogonal and non-orthogonal multiple access techniques, interleave-division multiple-access.
Taking into consideration the above mentioned, we present some of our recent results concerning the construction and investigation of serially concatenated space time convolutional codes and continuous phase modulation, the development of new coding techniques for codes over Gaussian integers and the construction and analysis of new four-dimensional signal constellations from Lipschitz integers for transmission over the Gaussian channel.
At the end of our presentation we describe spatial modulation (SM) which is a recently proposed modulation scheme for multi-antenna systems exploiting the space domain as well as the signal domain to modulate the information. We present some simulation results for SM in Nakagami fading channels, which provide a very good fit for all fading conditions ranging from very severe to no fading because of the presence of an adaptive parameter m called shape factor. Applications of Nakagami fading include modeling the wireless channel in microcellular systems, indoor wireless systems and mobile satellite systems.