BRAVE partners are proud to release their second deliverable regarding the sub-THz PHYsical layer modeling and design: D2.1, Propagation channel model and RF impairments definition and Waveform design.

This technical deliverable D2.1, provides valuable results on propagation channel and RF impairments modelling, proposed waveform, related transceiver architecture/algorithm and initial performance evaluation.

A first and very important achieved result is the achievement in developing tools validated with measurements at 28 GHz and 60 GHz used to analyze the channel propagation at 150 GHz frequency band. As a main observation, the channel at 150 GHz does not necessarily benefit from better conditions at higher node heights (as usually observed at lower frequencies). It can behave significantly different depending on the height of the nodes, power and angular sensitivity of the receiver and the considered transmit power.

The second important achieved result is to be able model the phase noise (PN) for sub-THz communications. We have first introduced two PN models: one correlated, accurate but complex, and another uncorrelated analytically simpler. We have also investigated the design of robust communications impaired by strong PN for future sub-THz applications.

Third, important achievements related with the development of the Generalized Spatial Modulation (GSM) MIMO System scheme for sub-THz communications are presented in this deliverable. Proposed scheme proves that the constant or near-constant envelope modulation CPM-GSM and (D)QPSK-GSM systems with limited number of RF chains, feasible antenna array size, and acceptable complexity are able to reach a high system spectral efficiency of 25b/s/Hz, and hence ultra-high data rates while maintaining a low power consumption. Last but not least, the deployment of the dual polarized antennas in GSM (DP-GSM) allows to add an additional level of indexation and leads to the increase of the spectral effciency (SE). The DP-GSM system offers the opportunities to be more robust against channel defficiencies such as Rician fading and inter-antenna correlation and to be beneficial for the spectral efficiency.