Programme Element: ARTES 5.1
Reference nr.: 12.1TT.06
Planned Tender Issue: quarter 4, 2013
(*) Priority 2 - a request for initiation has been received.
Objective: This technique allows implementing diversity in the feeder link using a lower number of gateways versus site diversity, reducing the ground segment cost. Scope of the activity is to demonstrate in small scale yet realistically the principle of the smart gateway for a Q/V-band feeder link exploiting the TDP5 Q/V-band payload on @SAT.
Targeted Improvements: Up to 50% reduction of number of gateways is possible at the expenses of a larger feeder link bandwidth/ground station EIRP. Reduction of feeder link HPA power on-board the satellite at the expense of some extra RF chains and switches required. In the return link with a 4:6 redundancy 50% TWTA power reduction is achieved.
Smart Site Diversity is a technique that aims at achieving availability performance similar to conventional Site Diversity (SD) but requiring less GWs. To achieve this purpose the faded gateway traffic shall be (evenly) distributed to the non-faded gateways by means of the terrestrial network. On the transmission side, to minimize the impact on the terminal to re-synchronise on the new carrier some synchronisation mechanism must be implemented between all the gateways. The user served by the "faded" gateway will get a quasi-seamless transition from one gateway to another. Considering the novelty of this technique, its importance for the exploitation of the Q/V-band for the feeder link and the possibility to have an early small-scale experimentation over the Q/V-band TDP5 payload on @SAT the following activity is proposed. In nominal conditions each gateway generates an uplink DVB-S2 carrier at V-band on a gateway specific frequency that is received back by third station emulating the user terminal. Each gateway is monitoring independently the Q-band downlink beacon. When the fading for gateway 1 exceeds the tolerable level then a shut down process is initiated:
- GW1 Traffic is routed to GW2 through the terrestrial network to the GW2 modulator
- GW1 F1 carrier transmission is tiered down while GW2 F1 carrier transmission is activated with minimum traffic disruption for the user.
When the fading event at GW1 is considered over the initial conditions is re-established. Although the test shall be performed on real fading events some emulation through insertion of a channel simulator on the GW uplink chain emulating the beacon fading shall also be envisaged. The activity could be arranged in four main tasks:
- Design and simulation of the proof of concept SSD
- Implementation of the demonstrator subsystems
- Testing in laboratory environment using a channel emulator
- SSD Proof of Concept over the air experimentation
(*) Priority 2 activities will only be initiated on the explicit request of at least one delegation.