SoftBank deployed CCS Metnet self-organizing microwave backhaul in Tokyo to test its performance in challenging urban environments. Metnet uses a self-organizing mesh architecture with wide-angle antennas to automatically detect line-of-sight and non-line-of-sight links between nodes. The trial in Tokyo's dense urban canyons demonstrated Metnet's ability to adapt to multipath reflections and maintain high throughput and availability on links as close as 32 meters apart. SoftBank found Metnet simplified backhaul deployment and ensured resilient connectivity that can support future 5G networks in difficult urban environments.

1. SoftBank Japan - rapid small cell
deployment in the urban jungle
Urban small cells deployed at street level are the next logical step to meet growing data
traffic demand in city centres. Practical solutions need to be quick and easy to install,
adapt seamlessly with tactical evolution and be resilient during outages. SoftBank
installed CCS Metnet self-organising microwave backhaul in the challenging metropolis
of Tokyo, delivering valuable insight into the behaviour of 5G microwave.
The world’s only self-organising
microwave backhaul
Enabling 5G

2. Ultimate flexibility
Planning deployment of urban small cells involves trade-offs between
three key capabilities – backhaul, power and site availability.
Network Topology
Planning deployment of urban small cells involves
trade-offs between three key capabilities – backhaul,
power and site availability. Seven nodes were
installed on existing telegraph poles, with two directly
connected by Gigabit fibre backhaul. The simplest
links were direct line-of-sight along the street, which
coped with reflections from buildings on both sides.
The most remote node had three wireless links
(hops) to reach fibre backhaul. The topology of the
deployment shown below is a live screenshot from
the Management System.
The site preferred by RF planners may not have
electrical power; fibre backhaul may be unavailable
and/or have long lead times to install; some sites
may be much more costly or inaccessible than
others. Flexibility is critical for success.
In the SoftBank implementation, CCS Metnet
simplified the planner’s dilemma by providing high
capacity, highly resilient wireless backhaul which
was able to be quickly deployed in the rapidly
changing environment of Tokyo.
Operating in the 26GHz band that is normally
constrained to Line-of-Sight, this live trials in
downtown Tokyo has proven NLoS (Non-Line-of-
Sight) as part of the mix.
Live screenshot of the deployment topology taken from the Management System.

3. No skilled tuning or calibration was required for these links – Metnet
automatically senses, filters and adapts to optimise performance and minimise
interference. This is a continuous on-going process, adapting to environmental
changes such as traffic movement, weather and foliage growth.
Rapid installation
All nodes use identical hardware with a single radio per
location. Single RF channel operation does not require any
RF planning, speeding and simplifying installation.
The node shown on the right is a typical street alley
deployment with its neighbour node further along the
canyon.
More unusual were NLoS (Non-Line-of-Sight) links
such as one shown below, where Metnet resolved and
adapted to multi-path reflections from nearby buildings.
The 270 degree wide angle 16 antenna array built into
each Metnet node captures a wide range of signals for
extensive processing and filtering. This is much easier
and more flexible than Point-to-Point radio links which
require alignment, where instead Metnet nodes with their
270degree antenna array automatically detect all possible
LoS and NLoS links and select them accordingly.
Metnet nodes installed on the streets of Tokyo (see purple circles)

4. Our customer’s experience with Metnet
Dense environments such as this are likely to have small cells spaced closer than 50 meters apart. One link was
32 metres measured as a direct path, with NLoS reflected signals travelling 49 metres. The adjacent nodes had 37
different possible RF links with varying attenuation levels, for which the best options are automatically calculated and
continuously reviewed. This demonstrated the high degree of multipath reflection that occurs in a typical street level
urban canyon. All potential Metnet links are shown in the diagram below.
This link achieved an average signal-to-noise ratio/
modulation of 12dB, supporting backhaul data
throughput of 135Mbps. The link achieved 100%
availability throughout the trial period. Round trip
latency ranged from 0.5ms (1 hop) to 0.88ms (3 hops).
The latest dual channel Metnet radios are capable of
delivering 1.2Gbps using 256QAM in a typical 112MHz
single channel pair.
Operating in a single channel pair without the need to
radio plan, the SON algorithm select the best possible
links and topology, and runs a dynamic spatial TDMA
schedule which dictates exactly which node and
antenna pair can transmit and receive so as not to cause
interference in the cluster. This is made possible by
the thousands of measurements which are taken every
second to determine the real time state of the mesh.
This cognitive approach to microwave networking
Automatic problem-solving
provides a robust and flexible platform in the most
challenging or urban environments.
Metnet addresses many of the issues of urban small
cell deployment, simplifying, adapting and ensuring
resilient high capacity backhaul can become available
to all.
A live deployment in downtown Tokyo is the
ultimate challenge for a small cell backhaul system.
Our engineering team was impressed with Metnet’s
unique MPtMP mesh architecture and approach, and
we wanted to test how this self-organising, self-
optimising, and self-healing microwave solution
performed in a dense urban area.
We designed the trial principally to assess Metnet’s
automatic support for NLOS, and its ability to cope
with multiple RF paths in a multipath propagation
environment – all while delivering optimal performance
and quality of service. Metnet’s capabilities fulfilled our
expectations. The trial has provided a valuable insight
into the behaviour of microwave and mmWave systems in
future 5G bands, and the results of our trial demonstrate
that Metnet can be well positioned to support these fifth
generation networks.”
Tomohiko Furutani
SoftBank Corp. Technology Strategy Office2

5. Speak to our team today
If you’d like more information on this subject or CCS products,
please don’t hesitate to contact our team.
3rd Floor, Mount Pleasant House,
Huntingdon Road,
Cambridge, CB3 0RN
+44 (0)1223 314 197
info@ccsl.com
www.ccsl.com