PAGE CONTENTS
Objectives
The objective of this activity is to investigate and design Ka-band multi-beam dual-polarization payloads for significantly higher capacity utilization with respect to conventional multi-beam payloads in the presence of unbalanced traffic demand.
In this respect, possible payload architectures and related technologies identifying key payload equipment for further development are to be defined, traded-off and assessed.
The activity covers the following aspects:
- analysis of requirements and architectural trade-offs;
- detailed design (including architectural and sub-systems design);
- analysis, simulation and optimization of performance;
- identification of required technology improvements and necessary developments;
- compare results in terms of capacity utilization improvement.
Ideally, to cope with peaks of capacity demand on hot spots (see Fig. 1) the payload should be flexible to the extent that the overall available user-link bandwidth in both the orthogonal polarizations (i.e. Dual-Polarization, DP) should be assignable to a limited number of beams, while maintaining the Single Polarization (SP) at user level on the remaining less-demanding beams.
In contrast to past and on-going activities at ESA, the aim of the present study is to explore the possibility of using dual-polarization for the hot spots, with flexibility to adapt to the traffic demand evolution.
The activity indeed targets a capacity utilization improvement of 40% with respect to conventional multi-beam payloads.
The outcomes of the activity are the detailed design of the payload architectures, including payload block diagrams, mass/power/dissipation budgets, delta cost estimation and a hardware matrix, and high level specifications for the identified new payload equipment.
Challenges
The design of flexible dual polarization payloads is particularly challenging for the mass/power/accommodation aspects and efficient solutions must reduce hardware replication due to the use of two polarizations for the user beams.
It is also important to consider the additional complexity and costs associated with advanced payloads. For operators, delta-costs associated with flexibility must be offset by (at least) an equivalent economic return (e.g. traffic capacity increase, improvement of the satellite fill-factor, extension of the addressable market, reduction of in-orbit spares, etc.).
For these reasons, the additional payload mass, power consumption and thermal dissipation is expected to be kept within a limit of 20%-30% with respect to a conventional multi-beam payload.
Plan
The activity is organized in 4 tasks as follows:
- Task 1 – System Requirements and Performance Evaluation Methodology
- Task 2 – Payload Technology Investigation
- Task 3 – Payload Trade-Offs and Preliminary Design
- Task 4 – Design Consolidation
During Task 1, the mission requirements are to be consolidated, including a set of traffic distributions, against which system capacity is to be evaluated.
Moreover, some study cases are to be defined, including conventional and advanced systems, both for a high number of beams (~70) and for a very high number of beams (³150).
In Task 2, a survey of existing Intellectual Property Rights related to Ka-band multi-beam dual-polarization satellite systems and relevant payload technologies are to be performed. Preliminary payload architectures are to be identified for each system study case.
During Task 3, the Contractor shall the system and payload performances are to be analysed and traded-off and the baseline payload architecture is to be selected and consolidated.
Finally, in Task 4, a European roadmap for the identified payload technologies and building block developments is to be elaborated.
