Satellite Data Communication

Technology Roadmap Sections and Deliverables

• 2SDC - Satellite Data Communication

This technology is described a the level 2 level as it is a delivered service. While the service could be split across many markets (e.g. selling bandwidth and owning satellite only), for the purposes of this roadmap, 2SDC includes the ground segment, space segment, and user equipment to enable Satellite Data Communications.

Roadmap Overview

The working principle and architecture of satellite data communication is depicted in the below.

Satellite-based internet/voice access is enabled by satellites, which provide relay to extend communication beyond traditional (terrestrial) line of site of the network and users. Data encoded in radio waves is sent between the ground station’s transceiver, relayed via the satellite, and the modem at the user’s location. Advances in technology include High Throughput Satellites (HTS) and some next-generation satellite systems may follow low-earth orbit rather than geosynchronous orbits, which would reduce latency dramatically.

Design Structure Matrix (DSM) Allocation

The 2-SDC tree that we can extract from the DSM above shows us that Satellite Data Communication (2SDC) is part of a larger abstraction of wireless duplex communication (1WDC), and that it requires the following key enabling technologies at the system level:

• 3SCP Satellite Communication Payload
• 3SGT Satellite Gateway Terminal
• 3USM User Satellite Modem
• 3UST User Satellite Terminal

In turn these require enabling technologies at level 4, the technology subsystem level:

• 4SRA Satellite Receive Antenna
• 4STA Satellite Transmit Antenna
• 4SCE Satellite Communication Electronics
• 4SGA Satellite Gateway Aperture
• 4GTE Gateway Transmit Electronics
• 4GRE Gateway Receive Electronics
• 4UMM User Modem Modulator
• 4UMD User Modem Demodulator
• 4USA User Satellite Aperture
• 4TSC Transmit Signal Conditioners
• 4RSC Receive Signal Conditioners

Roadmap Model using OPM

We provide an Object-Process-Diagram (OPD) of the Satellite Data Communication (2SDC) roadmap in the figure below. This diagram captures the main object of the roadmap, its decomposition into systems (gateway, satellite, user terminal, etc.), its characterization by Figures of Merit (FOMs) as well as the main processes (Transmitting, Receiving).

An Object-Process-Language (OPL) description of the roadmap scope is auto-generated and given below. It reflects the same content as the previous figure, but in a formal natural language.

Figures of Merit

The table below show a list of FOMs by which satellite data communication can be assessed.

Figure of merit	Units	Description
Throughput capacity	[Gb/s]	Rate at which the satellite can successfully deliver data to all end users
Latency	[s]	Amount of time needed to deliver data between the communication endpoints. Unless otherwise stated, we assume this to mean one-way latency between satellite and ground.
Per-user downlink rate	[Gb/s]	Downlink data rate as experienced by an individual user subscribed to the service.

Besides defining what the FOMs are, this section of the roadmap should also contain the FOM trends over time dFOM/dt as well as some of the key governing equations that underpin the technology. These governing equations can be derived from physics (or chemistry, biology ..) or they can be empirically derived from a multivariate regression model. The table below shows an example of a key governing equation governing (solar-) electric aircraft.

Inputs	Key relationship or governing equation	Outputs
Signal-to-noise ratio	Shannon-Hartley theorem: <math>C = B \log_2 \left( 1+\frac{S}{N} \right) </math>	Throughput capacity
Bandwidth
RF Design Parameters	<math> \frac{E_b}{N_o} = \frac{P_t L_l G_t L_a G_r}{k T_s B} \left( \frac{\lambda}{4\pi R} \right)^2 </math>	Link Margin:
Orbital distance	<math>t = d/c</math>	Latency