Description
The objective of this activity is to design, develop and test channel estimation and adaptation techniques as needed for Q/V band feeder links of LEO/MEO constellation with regenerative on-board processors. An end-to-end system testbed will be developed that includes varying channel, antenna and hardware impairments in the downlink and uplink depending on the elevation angle. The testbed will include the baseband, analogue and RF domain to test and evaluate the developed techniques.Targeted Improvements: - To improve the spectral efficiency of Q/V band feeder links for constellations by 30% in comparison to transparent feeder links.- To reduce by 20% the number of Q/V band gateways by allowing links to low elevation angles.Description: As Q/V band has only started to be deployed for GEO-based VHTS systems, broadband constellations in LEO/MEO are considering adapting this technology for their feeder links due to the wide spectrum and ease of coordination that the Q/V band offers compared to lower frequency bands. Different than in GEO, LEO/MEO feeder links need to operate in a large range of elevation angles. Low elevation feeder links are desirable to reduce the number of gateways but comes at a cost of link performance degradation. Furthermore, as next generation LEO/MEO are opting for regenerative payload, the possibility arises for a separate optimisation of the feeder link independently of user links. This activity will design, develop and test channel estimation and adaptation techniques as needed for Q/V band feeder links of LEO/MEO constellation with regenerative onboard processors. Channel impairments will be analysed and characterised down to low elevation angles including nonlinear distortions due to high power amplifiers, linear filter distortion (including ground station antenna feeds), radiowave propagation, digitisation process, modem etc. For the antenna part this will include impairments of mechanically steerable and phased array antennas. A combined hardware and software end-to-end system testbed will be developed representative of Q/V band LEO/MEO feeder links with regenerative payloads implementing varying impairments depending on the elevation angle. The developed channel estimation and adaptation techniques will be tested and the spectral efficiency improvement of the Q/V band feeder link for LEO/MEO constellations will be evaluated.