TELECOM INNOVATION HIGH ALTITUDE PLATFORMS DELIVER - Cambridge Wireless - Non Terrestrial Networks SIG, 22nd July 2021
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
TELECOM INNOVATION
HIGH ALTITUDE PLATFORMS DELIVER
Cambridge Wireless – Non Terrestrial Networks SIG, 22nd July 2021
Tim Fowler
20 July 2021 P2515-P-197 v1.0
This presentation follows work performed for
Stratospheric Platforms Limited (SPL),
pioneers in HAP-based services
Opinions expressed are those of Cambridge Consultants
20 July 2021 2 P2515-P-197 v1.0
LEO
(h ~ 200 – 2000 km)
HAPS have been considered for three decades
Flying at ~20km has many benefits… ISS
(h ~ 320 – 380 km)
1. Above Civil Aviation
2. Can see lots of the ground
3. Low-enough to deliver great services
– LEO satellite orbit ranges from 200 to 2,000 km altitude
10 – 100 times higher (20-40 dB further away)
HAPS
4. Moderate Wind Speed – So HAPS can “dwell” (h ~ 17 – 22 km)
– unlike LEO satellites
– a “skyhook”
20 July 2021 3 P2515-P-197 v1.0
Stratosphere offers good sight of the ground
Image Source: Google Earth
20 July 2021 4 P2515-P-197 v1.0
LEO has substantially greater area to illuminate
Image Source: Google Earth
20 July 2021 5 P2515-P-197 v1.0
But thin stratospheric air brings major challenges
A. Need to sustain flight
– Lighter-than-air craft will be large
– Powered-flight aircraft need low drag and lightweight design
B. Need to hold station
– Lighter-than-air craft have higher drag, so need more power
to hold station
– Powered flight craft need top speed to match max wind
speed in Stratosphere
C. Need to operate complex electronics reliably
– Need design for cooling due to low thermal mass
– And for extreme cold of air
20 July 2021 6 P2515-P-197 v1.0
Prior approaches to exploit stratosphere experienced a vicious circle
Limited
revenue =
low-cost
operation
Limited
Longer
niche app’s
endurance
only
Limited
Can’t carry
capacity to
fuel, so solar
“do work”
Limited
So must be
payload size
very light
and power
20 July 2021 7 P2515-P-197 v1.0
To be useful, HAPS need to have long endurance
▪ Long endurance high-altitude aircraft do exist
– Some more real than others
Typical HAPS Payload: 5 – 15 kg
▪ All constrained by two critical parameters Typical power for payload: 0.1 – 1 kW
– Very low mass
– Modest power budget
▪ Solar power is substantially less effective above
30 degrees latitude for all-year service
Image Source: Google Earth
20 July 2021 8 P2515-P-197 v1.0
SPL looked at the opportunity differently
What if the HAP wasn’t constrained to
low revenue niche applications?
What if it is possible to break that vicious circle?
20 July 2021 9 P2515-P-197 v1.0
SPL asked themselves two questions:
Image Source: SPL
1. What if we built a HAP that could lift and power an “industrial” payload?
a) unique airframe with 60m wingspan can carry 140kg
b) hydrogen power source generates high power
c) designed to fly through troposphere for refuel and maintenance
d) operate and hold station for >1 week
e) fly as a managed fleet of HAPs
► Innovative HAP platform and flight ops concept
2. What if we could deliver excellent connectivity services, rather than
restricted services to those with few options?
a) industrial scale telecoms, equivalent to 100’s of base stations
b) competitive network performance, that users prefer
c) low infrastructure delivers strong economic benefits
d) flexibility delivers operational benefits
► Innovative telecoms concept
20 July 2021 10 P2515-P-197 v1.0The SPL HAP is a significant breakthrough, worthy of its own talk;
able to carry an industrial payload, and provide the
power needed to deliver value
But, as this is a Cambridge Wireless SIG,
I’m going to focus on the novel Telecoms concept today
20 July 2021 11 P2515-P-197 v1.0So, how have Terrestrial Networks evolved
and why is there an opportunity for something new?
20 July 2021 12 P2515-P-197 v1.0Terrestrial Networks have evolved significantly over the last 35 years
Early networks were all about VOICE
1G
Base Better 1G Performance
(Analog) Station
Audio Quality
2G
Low bit-rate
Codec Effects (Digital)
Error Correction
Effects
Range (MS to BS) Better 2G Performance
20 July 2021 13 P2515-P-197 v1.0Terrestrial Networks have evolved significantly over the last 35 years
Early networks were all about VOICE
1G
(Analog)
Audio Quality
2G
(Digital) 2G Quality
Variability
Usable Cell
1G Quality
Variability
Range (MS to BS)
Key objective of 2G over 1G was to create a consistent service experience across the network
20 July 2021 14 P2515-P-197 v1.0Terrestrial Networks have evolved significantly over the last 35 years
Good cell-edge SINR as adjacent
cells on different frequencies
2G GSM Networks were designed with frequency re-use (minimum of 3) – limits spectral efficiency
20 July 2021 15 P2515-P-197 v1.0Terrestrial Networks have evolved significantly over the last 35 years
▪ 3G networks introduced single-frequency
operation via CDMA techniques
– CDMA techniques allowed many signals
in same frequency Poor cell-edge SINR at highest data
rates as adjacent cells on same
– But 3G was UMTS – Universal Mobile frequency
Telecommunications System
– Not just voice - data too
SINR (performance)
3G
3G suffered from “cell breathing”
Increased traffic reduces SINR and cell size Range (MS to BS)
20 July 2021 16 P2515-P-197 v1.0Terrestrial Networks have evolved significantly over the last 35 years
▪ 3G networks introduced single-frequency
operation via CDMA techniques
– CDMA techniques (ideal for narrow-band
voice in wideband channel) allowed Poor cell-edge SINR at highest data
rates as adjacent cells on same
many signals in same frequency frequency
– But 3G was meant to be UMTS –
Universal Mobile Telecommunications
System – not just voice but data too
SINR (performance)
▪ 4G built a truly mobile broadband network
▪ 5G had broadened the capabilities of 4G
and removed some constraints…
3G, 4G & 5G
Range (MS to BS)
20 July 2021 17 P2515-P-197 v1.0Terrestrial Networks have evolved significantly over the last 35 years
▪ 3G networks introduced single-frequency
operation via CDMA techniques
– CDMA techniques (ideal for narrow-band
voice in wideband channel) allowed Poor cell-edge SINR at highest data
rates as adjacent cells on same
many signals in same frequency frequency
– But 3G was meant to be UMTS –
Universal Mobile Telecommunications
System – not just voice but data too
SINR (performance)
▪ 4G built a truly mobile broadband network
Usable Cell
▪ 5G had broadened the capabilities of 4G
and removed some constraints…
3G, 4G & 5G
3G, 4G and 5G all deliver highly variable
performance, that users don’t understand Range (MS to BS)
20 July 2021 18 P2515-P-197 v1.0Single frequency networks deliver highly variable performance
Base Stations
Base Stations
Spectral Efficiency (Bit/s/Hz)
Spectral Efficiency (Bit/s/Hz)
20 July 2021 19 P2515-P-197 v1.0Most of Macro-cell path is obstructed
▪ Near-far problem (highly variable signal level,
dependent upon where the Base Stations are relative
to the user)
▪ Majority of signal path has some obstruction including
diffraction, absorption and reflection
– Within a short distance, we often can’t see the
users
20 July 2021 20 P2515-P-197 v1.0So, what if we could change this situation? 20 July 2021 21 P2515-P-197 v1.0
First benefit, the HAP has good sight of the ground ▪ At 20km height, and extreme 70km radius service area, we get same downward view as 25m tower at
But signal path is much longer… what about signal strength?
▪ Uplink limited by TX Power of handsets and data modems
▪ At 20km height, minimum path length is 20km, maximum could be ~70km
– ~33dB more path loss than LOS to ~1km BS
– 1km base station has significant other losses, rarely being LOS
▪ So for good uplink -> need ~30dB gain on HAP RX
– Set’s antenna aperture on HAP
– 3m diameter HAP antenna has sufficient gain at ~2GHz
70km 20km
20 July 2021 23 P2515-P-197 v1.0High-gain active antenna has narrow beam
Which means cells can be created that are small
~2km diameter
20 July 2021 24 P2515-P-197 v1.0What if signal level not dominated by near-far effects?
Power distribution across cell determined by 0
beam pattern, not distance from BS
Normalised Power (dB)
-20
-40
SINR (performance)
-60
Non-Terrestrial
-80
HAP -40 -20 0 20 40
Distance (km)
Benefit
Usable Cell
Terrestrial Signal Variability
Cell Centre Cell Edge
Benefit 2: More uniform “good” broadband service
20 July 2021 25 P2515-P-197 v1.0HAP-Based Systems can deliver more consistent services
Base Stations HAP Cells
Spectral Efficiency (Bit/s/Hz)
Spectral Efficiency (Bit/s/Hz)
Benefit 2: More uniform “good” broadband service
20 July 2021 26 P2515-P-197 v1.0Projecting service provides flexibility
There will always be areas of interference but, as we are
“projecting” cell patterns, it is possible to:
1. Move the cell centres dynamically:
– physically (in x and y) and
– Power
2. Combine beams to form “no-interference zones”
or simply larger “cells”
One beam can form a single cell or part of larger cell
– Capacity and coverage can be separated
Benefit 3: Flexibility to match demand
20 July 2021 27 P2515-P-197 v1.0The stratosphere offers a “Goldilocks-zone” between Terrestrial and Space
▪ The stratosphere is uncontrolled airspace
▪ High enough to cover large areas
per user served
Cost
– few HAPs required to cover large areas
▪ Low enough that aperture required to achieve
performance is achievable
▪ Modelling has shown significant cost savings
compared to terrestrial rollout
– One HAP can replace hundreds of Terrestrial
Base Station sites
User Population Density
people / unit area
Benefit 4: Economic to deploy in large market areas
20 July 2021 28 P2515-P-197 v1.0Telecoms from the stratosphere may not be what you thought
HAPS promise fantastic benefits
1. Better signal path to users (less clutter)
2. More uniform good broadband service,
– Less confusing for users
3. Flexible configuration to match traffic demand
4. Less terrestrial infrastructure leads to better economic performance for all but urban deployment
It will be much easier for operators to create ubiquity for mobile and IoT services with HAPS than without
20 July 2021 29 P2515-P-197 v1.0UK . USA . SINGAPORE . JAPAN www.CambridgeConsultants.com Cambridge Consultants is part of Capgemini Invent, the innovation, consulting and transformation brand of the Capgemini Group Registered no. 01036298 England and Wales 20 July 2021 P2515-P-197 v1.0
You can also read
