KDDI's Underground 5G Base Stations

Some five years back I talked about NTT Docomo's underground LTE base stations, now it's KDDI's turn for an underground 5G base station. Last week the Japanese operator KDDI announced to the world that they are testing an underground base station in a handhole (just big enough for the hand to go in as opposed to manhole where a person can go in). 

The press release (translated by Google from Japanese) said:

In December 2022, KDDI became the first domestic telecommunications carrier to begin operation of an embedded 5G base station (hereafter referred to as this base station) in Otemachi, Chiyoda-ku, Tokyo (on the premises of the KDDI Otemachi Building).

In the future, we aim to accelerate the expansion of areas that require consideration of scenery, such as Bikan districts, by utilizing this base station

Background

Conventional tower-mounted base stations and building roof-mounted base stations have exposed base station antennas, which can affect the scenery. It was. As one solution to this problem, the introduction of buried base stations, in which the base station equipment is installed underground (below the ground surface), is expected. In July 2021, the Ministry of Internal Affairs and Communications' new system of radio wave protection guidelines for embedded base stations came into effect.

About this base station

Since 2018, KDDI has been considering the start of commercial operation of embedded base stations. In December 2022, we succeeded in emitting radio waves from this base station, and verified radio wave propagation characteristics until February 2023, confirming that a communication area with a radius of about 50m can be secured.

By storing the devices necessary for radio wave radiation, such as wireless devices and antennas, in a housing buried underground (below the ground surface), it is possible to install the device in consideration of the landscape. In addition, by radiating radio waves upward, it will be an area along the ground.

It adopts a highly waterproof metal housing and is designed to withstand water intrusion. Also, since the antenna is underground, it is less susceptible to strong winds.

KDDI will continue to develop new concept base stations that are not bound by existing base station installation forms, and will continue to expand service areas, improve quality, and create an environment that is easier for customers to use.

n78(3.7G)離れても掴むから別みたい
もしかしてn77(4.0G)マンホールから吹いてる?
なお、このマンホール基地局を作るのにKDDIは周りに木もたてたようなので
ガーデニング基地局という名称になりましたｗ pic.twitter.com/TonrSLJ08M

— 電波やくざ@告白実行委員会😌💕 (@denpa893) March 11, 2023

Nice to see mobile enthusiasts already testing the base station out. We will have to wait to see how the PoC goes and if we will see more of these deployed commercially. 

Related Posts: 

• Telecoms Infrastructure Blog: NTT Docomo's Underground LTE Small Cells with possibility to deploy 5G in future
• Telecoms Infrastructure Blog: Underground Small Cells
• Telecoms Infrastructure Blog: Small Cells & Wi-Fi in the pavements & roads
• Telecoms Infrastructure Blog: KDDI Plans to Improve Rural Connectivity in Japan using SpaceX's Starlink
• Telecoms Infrastructure Blog: KDDI to test 5G with base stations built in Street Lights
• Free 6G Training: KDDI's Seven B5G/6G Technologies Contributing to Society 5.0 Implementation
• Operator Watch Blog: KDDI Japan's IoT march continues with over 10 Million Connections
• Operator Watch Blog: Japan allocates 5G Spectrum in 3.7GHz, 4.5GHz and 28GHz bands 

London Underground Mobile Network Infrastructure

Earlier we made a tutorial on Infrastructure required for bringing connectivity to underground rail network. So it was good to see Nick Hudson, Director of Global Partners & Programmes at BAI Communications share some pictures of Mobile Network Infrastructure on London Underground network on his LinkedIn post.

Back in June 2021, BAI Communications (BAI) was awarded a 20-year concession by Transport for London (TfL) to deliver high-speed mobile connectivity across the capital in the most advanced and largest infrastructure project of its type in the world. The press release said:

BAI’s partnership with TfL will establish a long-awaited backbone of connectivity with a city-wide integrated communications network delivering multi-carrier cellular, Wi-Fi, and fibre connectivity services. The 4G-enabled and 5G-ready communications network that BAI will build and operate as a neutral host for fixed and mobile operators will fast-track London’s evolution as a smart city. BAI will also help to create a safer, smarter London by building and operating critical communications infrastructure that will support police, fire, and ambulance services.

The first phase of the project will see the rollout of modern multi-carrier infrastructure. This will allow fixed and mobile operators to immediately provide continuous 4G coverage to their customers across the London Underground stations and tunnels. The new wireless infrastructure will also be 5G ready. Work on the project will begin immediately, with all stations and tunnels due to have mobile coverage in four years.

Additionally, a new high-capacity fibre network running throughout the London Underground will enable fibre service providers to provide full fibre connectivity to premises across the city. The network will connect to buildings and street assets housing small cells to leverage the power of 5G and the IoT, and deliver improvements in areas like traffic congestion, public safety, and city planning.

Uses leaky feeder / DAS system to link base station hotels on the Tube

Not Open RAN - this is more old school, it seems

Can do 3.5GHz in stations but tunnels are all <2.1GHz pic.twitter.com/EPN91vdgRP

— Dean Bubley (@disruptivedean) November 16, 2021

Through this concession, BAI will help the transport authority support London’s post-covid recovery as travel resumes, delivering seamless 5G ready connectivity that will enable people to move around the city more efficiently, safely, and securely. More specifically, this project will enable TfL to reduce overcrowding and manage station flow, while improving safety with real-time information and reliable ‘from anywhere’ communications.

BAI was awarded the concession after a competitive tender process. The company has proven experience deploying mission critical communications networks in highly dense urban environments, including the underground rail networks in New York, Toronto, and Hong Kong. This project supports BAI’s strategic intent to sustainably accelerate growth globally. This is achieved through our work deploying outdoor neutral host infrastructure and developing 5G-driven offerings that introduce and scale connectivity solutions for emerging services and fresh revenue opportunities. Ultimately, our work supports our customers by delivering better connectivity and enhanced customer experiences. BAI’s ambitious plans include expanding its wireless infrastructure business across the public transport sector and growing its private network services portfolio.

Last month, BAI announced that they have completed the first milestone of its rollout of high-speed mobile coverage across the London Underground as it launches a permanent 4G service on the eastern section of the Jubilee Line. The press release said:

Customers of Three and EE are the first to be confirmed to have permanent access to 4G and 5G-ready communications between Westminster and Canning Town. The connectivity has been available as part of a pilot service since March 2020. This follows agreements made last year by both mobile operators to join BAI’s network, making them the first to cement their commitment to providing coverage to London Underground passengers.

Whilst on this section of the Jubilee Line, customers will continue to be able to check the latest travel information, keep on top of their emails, catch up on social media, live stream videos wherever they are on the Underground.

Cities all over the world are improving connectivity for subways and metros. With London already a centre of mobile connectivity, it's surprising that getting coverage in the Tube took so long.

Related Posts: 

• Telecoms Infrastructure Blog: Bringing Connectivity to Underground Rail Network
• Connectivity Technology Blog: Deutsche Bahn to get Seamless Mobile Network Along all Tracks
• Connectivity Technology Blog: China Unicom Brings 5G Connectivity to Nanjing Metro
• Connectivity Technology Blog: Paris Metro is now 100% covered with LTE
• Telecoms Infrastructure Blog: Underground Small Cells
• Telecoms Infrastructure Blog: Small Cells on the Train - A 2 hop solution 

Bringing Connectivity to Underground Rail Network

It's always been a challenge to bring mobile connectivity to commuters in the underground rail network. The same challenges extend to mines and other facilities under the ground. One solution that has been widely adopted is the use of leaky feeders as antennas.

This solution is also used to compliment the existing terrestrial network in case of tunnels. We made a small tutorial looking at this from metro point of view but the same solution is applicable in many different scenarios. 

The video and slides are embedded below

Beginners: Connecting Underground Railway Network from 3G4G

5G presents a small challenge for this as it is tricky to go beyond 4T4R easily. Each T/R requires a leaky feeder which makes it expensive as well as challenging in other scenarios.

Related Posts: 

• Connectivity Technology Blog: Deutsche Bahn to get Seamless Mobile Network Along all Tracks
• Connectivity Technology Blog: China Unicom Brings 5G Connectivity to Nanjing Metro
• Connectivity Technology Blog: Paris Metro is now 100% covered with LTE
• Telecoms Infrastructure Blog: Small Cells on the Train - A 2 hop solution 

Vodafone UK improving coverage with Phone Boxes, Mini-masts & Manhole Covers

Scott Petty, CTO of Vodafone UK wrote a post about how 'our cunningly imaginative network team has devised some ingenious ways of boosting mobile reception.' While readers of this blog will have already seen most of these innovations from around the world on our blog, it's nevertheless an important step to bring connectivity to users in rural and remote areas that suffer digital exclusion.

Late last year, Vodafone talked about how their mini masts (picture on top) are making huge differences to JCB Staffordshire quarries. Around half the height of a standard mast, the mini masts can be painted to fit in with the local surroundings. The masts also require less power and electronic equipment.  This means they are ideally suited to providing a mobile signal in hard-to-reach rural business locations, such as the two JCB sites, near its World Headquarters. The mini mast is developed in partnership with infrastructure technology company Commscope according to the PR.

Continuing from the original PR:

4G networks can easily become congested in densely populated cities. This is especially true for urban areas regularly visited by waves of tourists, such as London’s Covent Garden. Fitting a mini-mast to the underside of a manhole cover to increase mobile coverage may sound bizarre, but it makes perfect sense. Our incredibly fast fibre optic network runs beneath the streets of Covent Garden and provides the bandwidth muscle behind our manhole cover mini-masts. Each mini-mast isn’t designed to boost coverage for all of London or even the West End, but for specific stretches of Covent Garden where overwhelming demand for a strong and stable 4G signal would otherwise go unmet.

But manhole cover mini-masts won’t be appropriate or possible in every locality. For some places, such as Edinburgh’s historic Princes Street, mini-masts built into phone boxes make more sense. These converted phone boxes not only provide a boost to mobile reception on this bustling thoroughfare, but help preserve a much-loved icon of our national urban heritage.

In a post back in December, I wrote about Small Cells in Phone Boxes here.

In another press release yesterday, Vodafone said:

Picture source: ThinkSmallCell

Visitors to the popular seaside resorts of Polzeath and Sennen Cove in Cornwall this Easter can now receive fast mobile Internet and great voice reception along the beach after Vodafone installed the latest 4G technology in beachfront phone boxes.

Mobile coverage can often be difficult to provide in remote areas and coastal locations due to the local topography and the lack of power and fibre cables needed to link up masts. Vodafone is continually looking at new ways of providing customers with great coverage, including by installing 4G technology into traditional phone boxes, returning them to their roots.

Beach-goers will not only be able to use their smartphones on Vodafone’s ‘4G from a phone box’ service within approximately a 200-metre radius. They can also make use of Vodafone’s range of connected devices, including the V-Pet Tracker to help you pinpoint a dog that has wandered off.

Vodafone is working on a number of initiatives to help support the Government’s ambition of extending mobile coverage to 95% of UK landmass by 2022. In addition to drawing up industry-wide proposals to create a single rural network to cover not spots and partial not spots, last year, Vodafone achieved an industry first by installing the UK’s first mini mobile mast at Porthcurno in Cornwall.

The Cornish 4G-enabled phone boxes are equipped to cope with the increase in mobile usage over the Easter break and over the summer months. During the heatwave in 2018, our network in Cornwall carried nearly 90% more mobile Internet traffic than the previous year.

Vodafone is also testing 4G in phone boxes in busy shopping areas in Edinburgh, Oxford and soon in London. At its technology headquarters in Newbury, Berkshire, Vodafone is trialling housing 4G on the underside of manhole covers.

Who knew? Now network coverage is being provided via toughened resin manhole covers with the equipment hidden below & in the top of old phone boxes. Popped to @VodafoneUK to take a look at this latest effort to improve its coverage. pic.twitter.com/qGCxhcBAvv

— Ben Wood (@benwood) December 14, 2018

All pictures, unless mentioned are from Vodafone.


Related posts:

• Telecoms Infrastructure Blog: Small Cells in BT Phone Boxes
• Telecoms Infrastructure Blog: Underground Small Cells
• Telecoms Infrastructure Blog: NTT Docomo's Underground LTE Small Cells with possibility to deploy 5G in future
• Telecoms Infrastructure Blog: Rural Small Cells: An end user story

NTT Docomo's Underground LTE Small Cells with possibility to deploy 5G in future

NTT Docomo has announced that they have developed a prototype of manhole type base station for the first time in Japan. They will be used in locations where there is no other infrastructure available in vicinity to host base stations. The antenna is installed at a depth of 10 cm under the ground, with a fiber connection to the radio equipment and the power supply are drawn from the ground by the underground buried piping. The service area is about 90 m radius. 

Based on this, I am not sure if this is a complete small cell or just a remote radio head. I am inclined to think that this is a complete base station as its a standard LTE base station as per the specifications.

Manhole type base station specification (Sapporo verification station)

method	FDD-LTE
frequency	1.5 GHz band (BAND 21)
Bandwidth	15 MHz
MIMO compatible	2 × 2 MIMO
Downlink modulation scheme	256 QAM
Maximum Throughput	DL: 150 Mbps / UL: 37.5 Mbps
Size (buried part)	70 cm × 70 cm × 70 cm
Device size	About 29 cm × about 17 cm × about 7.5 cm
weight	Approximately 15 kg

Specification of manhole cover (Sapporo Verification Bureau)

size	Diameter 64.8 cm · thickness 5 cm
weight	Approximately 27 kg
Load bearing capacity	25 tons

The output power is not specified but base stations can easily fit within 15 kgs.

I have written about underground small cell here and here, which was about Swisscom, Ericsson & Kathrein trying it in Switzerland. I have also written about how the Japanese operator KDDI is trying to cover similar locations using lamp posts here. Its good to see Docomo trying something new.

As per the announcement, DoCoMo will work to improve the communication environment to areas where it was difficult to establish a base station, aiming for full-scale operation within the year 2018, and will continue to consider the application of future technologies to 5G in parallel.

From what I have heard, some antenna manufacturers are working on trying to convert the manhole cover in to an antenna. Its going to be a big challenge though.

Related Posts:

• Telecoms Infrastructure Blog: KDDI to test 5G with base stations built in Street Lights
• Telecoms Infrastructure Blog: Underground Small Cells
• Telecoms Infrastructure Blog: Small Cells & Wi-Fi in the pavements & roads
• Small Cells, Macrocells, Backhaul, Infrastructure and other connectivity solutions from #MWC18
• Macrocells, Small Cells & Hetnets Tutorial

Underground Small Cells

Following on from my earlier post on 'Small Cells & Wi-Fi in the pavements & roads', here are some more details about these underground small cells, see video below.

From Ericsson's press release:

Swisscom and Ericsson have deployed the world’s first vault site for LTE and small cells in Switzerland. Some 250 further rollouts are due in the country’s cities during 2016.

Swisscom and Ericsson have proved that city manholes can be used worldwide to improve capacity with small cells – even below street level – using the Ericsson Vault Remote Radio Unit and Kathrein’s Street Connect, an in-ground microcell antenna system. The use of existing street manholes where fiber and power already exists lowers total cost of ownership by 50 percent.

This, the world’s first vault site for LTE and small cells has been approved by the Swiss authorities, and 250 new rollouts are due during 2016 in the country’s cities. The solution effectively addresses cities’ needs by enabling the reuse of existing assets and underground space.

This site solution offers the best network capabilities in Switzerland by supporting the upcoming rollout of 5G.

Here is the video:



Related Posts:

• NTT Docomo's Underground LTE Small Cells with possibility to deploy 5G in future
• Small Cells & Wi-Fi in the pavements & roads

Small Cells & Wi-Fi in the pavements & roads

Back in October last year, Thinksmallcell reported that Vigin Media in UK is deploying WiFi in pavements.

ISPreview reports that:

Ordinarily most operators prefer to install WiFi access points above ground, not least because it helps the 2.4GHz signal to propagate, but telecoms infrastructure owners like Virgin Media have a lot of manholes around the place that can also be used (makes it easier to tap directly into their core capacity links) and apparently this approach can still cover an area of up to 80 metres.

The use of a submerged rainproof access point, which sits beneath a specially developed resin cover, is certainly a different twist on the usual deployments. Never the less Virgin Media are also using plenty of traditional access points too, which have been discreetly installed on local street furniture.

Wireless antenna maker Kathrein has teamed with Ericsson and Swiss operator Swisscom to develop an in-ground antenna system that will help provide additional wireless coverage in densely populated areas. The technology, called the Kathrein Street Connect, was developed to help operators deploy additional cell sites in places where site acquisition is difficult due to zoning issues.

Kathrein designed the antenna while Ericsson provided the radio. The rugged solution was designed to withstand deploying in streets with heavy vehicle traffic. Currently there are 17 sites piloting the technology in Switzerland with plans for commercial deployment in 2016, said Jim DeKoekkoek, product line manager for antennas and filters at Kathrein, in an interview with FierceInstaller.

Kathrein also has a video on Youtube explaining this:


Its interesting to see that pavements and roads may become the new battleground for providing connectivity through Wi-Fi and Small Cells.

Related Posts:

• Telecoms Infrastructure Blog: NTT Docomo's Underground LTE Small Cells with possibility to deploy 5G in future
• Telecoms Infrastructure Blog: Underground Small Cells