Types of NTN Devices: Smartphones, IoT Devices and VSAT Terminals
INTRODUCTION Types of NTN Devices
A variety of devices can connect to a Non-Terrestrial Network (NTN). These devices can have significantly different capabilities in terms of transmit power, antenna gain, device size, and communication requirements.
The characteristics of the user terminal have a direct influence on the achievable data rate or throughput for a given satellite constellation.
Common examples of NTN devices include:
Smartphones
IoT devices
Very Small Aperture Terminals (VSATs)
Other custom NTN terminals
Understanding the characteristics of these devices is essential for designing NTN systems and determining which services can realistically be supported.
1. Smartphones as NTN Devices
Smartphones are expected to represent a significant portion of user devices connecting to NTN systems.
The integration of satellite connectivity into smartphones is particularly important because it can extend communication capabilities to areas where conventional terrestrial networks are unavailable.
However, smartphones have certain physical and power limitations.
Compared with dedicated satellite terminals, smartphones generally have:
Limited transmit power
Low-gain antennas
Small physical form factor
Limited antenna capability
These characteristics can restrict the achievable satellite link performance.
Therefore, in the initial NTN deployments, the supported data rates may be relatively small.
2. Low- and Medium-Data-Rate Services on Smartphones
Because of the limited transmit power and low-gain antennas of smartphones, low- or medium-data-rate services may be more common during the initial stages of NTN deployment.
One important example is Short Message Service (SMS).
Satellite connectivity through smartphones can be particularly useful for communication in remote areas or situations where terrestrial cellular coverage is unavailable.
The initial focus on relatively low-data-rate services does not mean that smartphones cannot eventually support more advanced satellite services. Rather, the achievable performance depends on improvements in:
NTN network design
Smartphone antenna technology
Satellite capabilities
Link-budget optimization
Network architecture
3. Satellite Connectivity in Smartphones
Some modern smartphones have already introduced satellite-based communication capabilities.
For example, certain iPhone models, including:
iPhone 14
iPhone 14 Pro
iPhone 15
iPhone 15 Pro
can connect to a satellite for specific services such as:
Texting emergency services
Requesting roadside assistance
Sharing the phone's location
This illustrates how satellite connectivity is increasingly becoming integrated directly into consumer mobile devices.
Instead of requiring a dedicated satellite phone or external terminal, users can potentially access specific satellite services directly through their smartphones.
4. Voice Services and NTN Cell Capacity
Voice communication presents another consideration for NTN systems.
For a given NTN cell, increasing the number of simultaneous voice users can require a trade-off between voice quality and cell capacity.
One approach is to use low-rate voice services.
By reducing the data rate used for individual voice services, the system can potentially support a higher number of simultaneous voice connections within an NTN cell.
Therefore, NTN system design may involve a trade-off:
Voice Quality ↔ Data Rate ↔ Number of Supported Users
This approach can be useful when maximizing the number of voice users supported by a particular NTN cell is more important than maintaining the highest possible voice quality.
5. IoT Devices as NTN Devices
Internet of Things (IoT) devices represent another important category of NTN devices.
Many IoT applications do not require high data rates.
Instead, they often require:
Low data rates
Delay-tolerant communication
Wide-area coverage
Low-cost connectivity
Reliable communication from remote locations
Therefore, low-rate and delay-tolerant services are adequate for many IoT devices.
This makes NTN particularly attractive for large-scale IoT deployments in locations where terrestrial connectivity is limited or unavailable.
6. Massive IoT Connectivity Through NTN
One of the major advantages of NTN is its ability to provide connectivity across very large geographical areas.
A massive number of IoT devices can be distributed across a large remote region.
Instead of deploying terrestrial infrastructure individually for every small area, a large NTN cell can potentially provide coverage to many of these devices.
For example, IoT devices distributed across:
Remote rural regions
Large geographic areas
Difficult-to-reach locations
Other areas without terrestrial infrastructure
can potentially connect through an NTN.
This can lead to cost-effective coverage for large numbers of IoT devices.
The large coverage area of an NTN cell is therefore particularly valuable for applications involving widely distributed IoT devices.
7. Custom NTN Terminals
In addition to smartphones and IoT devices, custom terminals with high-gain antennas are common in pre-5G NTN systems.
These terminals are also likely to represent a significant portion of user devices connecting to NTN systems.
Unlike smartphones, which must operate with small integrated antennas and limited power, custom satellite terminals can use larger and higher-performance antennas.
One important example is the:
Very Small Aperture Terminal (VSAT)
8. Very Small Aperture Terminal (VSAT)
A VSAT is a dedicated satellite communication terminal that utilizes a high-gain antenna.
The high-gain antenna provides advantages such as:
Higher received signal strength
Improved link performance
Greater transmit capability
Compared with a smartphone, a VSAT can be designed specifically for satellite communication rather than being constrained by the size and power requirements of a handheld consumer device.
This makes VSATs suitable for applications requiring more capable satellite connectivity.
9. Examples of Custom NTN Terminals
Examples of custom satellite terminals include terminals associated with major emerging satellite systems such as:
Starlink
Project Kuiper
Eutelsat OneWeb
These terminals are designed specifically to communicate with their respective satellite networks.
The use of dedicated terminals allows the system to take advantage of higher antenna gain and other hardware capabilities that are generally difficult to achieve in a conventional smartphone.
10. Device Characteristics and Achievable Throughput
The characteristics of an NTN user device directly influence the performance that can be achieved from a satellite constellation.
Important terminal characteristics include:
Transmit Power
Higher transmit power can improve the ability of a device to establish and maintain a satellite link.
Antenna Gain
A higher-gain antenna can improve the received signal strength and link quality.
Antenna Size
Larger antennas can generally provide higher gain and improved satellite connectivity.
Device Power Availability
Battery-powered smartphones and IoT devices have different power constraints compared with dedicated satellite terminals.
Communication Requirements
A device requiring only occasional small data transmissions has very different requirements from a terminal intended for broadband Internet access.
Therefore, NTN network performance cannot be considered independently of the characteristics of the user terminal.
11. Comparison of Major NTN Device Types
Characteristic | Smartphones | IoT Devices | VSAT / Custom Terminals |
Primary Use | Consumer communication | Monitoring, tracking, sensing | Dedicated satellite connectivity |
Antenna | Low-gain integrated antenna | Typically compact antenna | High-gain antenna |
Transmit Power | Limited | Generally low | Higher capability |
Data Rate | Initially low/medium | Low | Higher |
Typical Traffic | SMS, emergency communication, selected services | Small, delay-tolerant data | Broadband and other higher-capacity services |
Coverage Requirement | Personal/mobile | Large-scale distributed coverage | Dedicated geographic/service coverage |
Power Constraint | Battery-powered | Often highly power-constrained | More flexible power availability |
Example | Satellite-capable smartphone | Remote IoT sensor | VSAT, Starlink/Kuiper/OneWeb terminal |
12. Relationship Between Device Capability and Satellite Network
The achievable performance of an NTN system depends on both the satellite constellation and the user device.
For example, a satellite may have substantial capacity, but a smartphone with a low-gain antenna and limited transmit power may not be able to utilize the full capacity available from that satellite link.
Similarly, an IoT device may not require high throughput at all. Its primary requirement may simply be reliable, low-rate connectivity over a very large area.
A VSAT or other custom high-gain terminal, on the other hand, can take advantage of stronger satellite links and support higher-capacity applications.
Therefore, NTN system design must consider the relationship between:
Satellite Capability + Terminal Capability + Application Requirements
13. NTN Devices Enable Different Service Categories
The diversity of NTN devices enables NTN systems to support a wide range of services.
Smartphone-Based Services
Smartphones can support applications such as:
Emergency messaging
Location sharing
Roadside assistance
Low- and medium-data-rate communication
IoT-Based Services
IoT devices can support:
Asset tracking
Remote monitoring
Sensor communication
Other low-rate, delay-tolerant applications
Custom Terminal Services
High-gain custom terminals can support:
Higher-rate connectivity
Broadband applications
Enterprise connectivity
Dedicated satellite communication services
Thus, different terminal types allow the same broad NTN ecosystem to address very different connectivity requirements.
Conclusion
A variety of devices can connect to a Non-Terrestrial Network, and the characteristics of these devices have a significant impact on the achievable throughput and supported services.
Smartphones are expected to form a major portion of NTN user devices. However, their limited transmit power and low-gain antennas can restrict achievable data rates, particularly during the initial stages of NTN deployment. Consequently, services such as SMS, emergency communication, location sharing, and other low- or medium-data-rate applications can be particularly relevant.
IoT devices represent another important NTN category. Many IoT applications require only low-rate and delay-tolerant communication. The ability of an NTN to cover large geographical areas can make it possible to connect massive numbers of IoT devices distributed across remote regions in a cost-effective manner.
Finally, custom high-gain terminals, such as VSATs, are important for applications requiring stronger satellite links and higher data rates. Terminals associated with systems such as Starlink, Project Kuiper, and Eutelsat OneWeb are examples of dedicated NTN terminals.
Ultimately, NTN performance depends not only on the satellite constellation but also on the capabilities of the device communicating with the satellite. Factors such as antenna gain, transmit power, device size, power availability, and application requirements all influence the achievable data rate and overall system performance.
Understanding the different NTN device types is therefore essential for designing and deploying efficient 5G NTN and future 6G satellite-integrated networks.
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