2G/3G Shutdown may Cost Lives as 4G/5G Voice Roaming is a Mess

You have probably heard me a complaining about the pace of VoLTE rollout, 2G/3G shutdowns, 4G Voice roaming, etc. This post highlights all these issues coming together in a dangerous way. People often ask me why is it that it's always just me highlighting the issues. The answer is that there are other people but their voice may not reach you. In this post, I am highlighting presentations by Rudolf van der Berg, Project and programme manager at Stratix Consulting.

No more voice roaming in USA! French operator Free warns customers that telephony in USA doesn't work. 2G/#3G shutdown and lack of #VoLTE standardisation and roaming are the cause. Its customers can only use Internet and SMS, but not E.164 number based voice telephony and 911! https://t.co/cbBrNZTskq

— Rudolf van der Berg (@internetthought) April 6, 2022

Let's start with Rudolf's post from LinkedIn:

Stop the shutdown of 2G and 3G networks to save lives. This is the urgent call I make today and I hope you can help me spread it! Please call on people you know in politics, regulators and emergency services to demand a stop! Call on anyone you know in the GSMA, 3GPP, handset makers (Apple, Samsung, Qualcomm, MediaTek), network builders (Ericsson, Nokia, Huawei) to re-engineer VoLTE to an interoperable standard.

Emergency calls (112, 911) should work anywhere in the world on any phone. For GSM and 3G voice calling it did. You could fly anywhere and call emergency services and in the EU we have the roaming regulation that demands calling like at home. Voice over 4G and 5G hasn't been properly standardized and isn't interoperable between networks, devices, chipsets and firmware. People need to be able to make and receive telephone calls around the world, to each other and to emergency services. Unfortunately even according to sector itself emergency services are at risk from VoLTE. A consumer today can't know whether a phone they bought will make VoLTE calls at home or abroad, nor whether it can reach emergency services. That can't be right!

So please help EENA 112 and me share this message! Thank you #eena2022 (Slide 4 contains a mistake, T-Mo USA hasn't decided on 2G shutdown yet. that is good for availability of 911, though fundamental point remains. Apologies.)

Dear foreigner, AT&T regrets you die because you can't dial 911. Try whatsapp and ask a friend in the US to call 911 for you. https://t.co/KqliBXv4ik

— Rudolf van der Berg (@internetthought) April 15, 2022

The video and slides are embedded below:

The slides contain many useful references and links, you can download directly from here.

Back in April, iBASIS hosted a VoLTE and 5G Roaming Roundtable. You can watch the video here and download the presentation and whitepaper as well. It contains talks from Kaleido Intelligence, iBASIS, KPN, Bouygues Telecom and Telus. 

The slide from Dutch MNO KPN above highlights the VoLTE Roaming issues they are observing. Other operators will face this issue sooner or later as well. 

So they are the ones who should be asked to make sure that VoLTE and VoNR is interoperable between vendors and MNOs? Because people will die if we don't fix this. See my presentation from last week https://t.co/Ju3GadO9ie

— Rudolf van der Berg (@internetthought) May 5, 2022

The Regulators, GSMA and 3GPP have to come together to fix this important issue for once and all so no lives are lost because of this. Hopefully someone is listening!

Related Posts: 

• The 3G4G Blog: Transitioning from eCall to NG-eCall and the Legacy Problem
• The 3G4G Blog: GSMA Releases Mobile Economy Report 2022
• The 3G4G Blog: When will 2G & 3G be switched off now that 5G is here?
• The 3G4G Blog: VoLTE Hacking
• The 3G4G Blog: A quick starter on 4G voice (for beginners) 

AT&T Cybersecurity Experts Provide 5G Security Overview

The National Governors Association (NGA) in the USA is the voice of the leaders of 55 states, territories, and commonwealths. On May 24th, the Resource Center for State Cybersecurity featured a panel of experts from AT&T for a conversation on understanding the 5G ecosystem, security risks, supply chain resilience and the challenges and opportunities that exist around deployment.

The talk highlighted top 5G security areas of concern. The top three being:

• Increased attack surface due to massive increase in connectivity
• Greater number & variety of devices accessing the network
• Complexity of extending security policy to new types of non-traditional and IoT devices

Some of the Security Advantages with 5G are highlighted as follows:

• Software Defined Networking/Virtualization
• Stronger 3GPP encryption for over-the-air encryption
• Subscriber Identity Privacy
• Roaming or network-to-network protection
• Network Slicing

The slides of the talk is available here and the video is as follows:

Related Posts:

• The 3G4G Blog: Everything you need to know about 5G Security
• The 3G4G Blog: Lawful Intercept in 5G Networks
• The 3G4G Blog: Key Technology Aspects of 5G Security by Rohde & Schwarz
• The 3G4G Blog: 5G Roaming with SEPP (Security Edge Protection Proxy)
• The 3G4G Blog: Evolution of Security from 4G to 5G
• The 3G4G Blog - Tutorial: Service Based Architecture (SBA) for 5G Core (5GC)
• 3G4G: Security in 2G, 3G, 4G & 5G Mobile Networks
• 3G4G: 5G (IMT-2020) Wireless 

5G Integrated Access and Backhaul (IAB) Enhancements in Rel-17

It's been a while since I last wrote about IAB on this blog here. At that time 3GPP Release-16 was being discussed. Since then things have moved on. While Release-16 is being prepared for final release soon, Release-17 study and work items have just been agreed upon.

IAB is included as part of Rel-16 but there isn't a comprehensive document or presentation easily available to details all that it will contain. Similarly the enhancements for Release-17 are available only superficially. Qualcomm is well known for making some really excellent presentations available on 5G. One of their presentations from January (here) has some details on IAB (pg. 32 - 35). There was also an excellent presentation by Navid Abedini, Qualcomm from IEEE Sarnoff Symposium, 2019 which is embedded at the end.

In a 3GPP RAN#84 discussion document RP-191181, Samsung has provided a comprehensive summary of what is being done as part of Rel-16 and what did not make in that:

• Rel-16 IAB aims at basic operations
• Architecture and protocol design
• IAB integration procedure 
• Routing, BAP and BH configuration
• CP and UP data transmission  via IAB
• Topology support: 
• Spanning Tree (ST) and Directed acyclic graph (DAG) 
• Intra-Donor adaptation is prioritized
• The following cannot  be supported in Rel-16
• Mobile IAB
• Topology support: Mesh
• Some functionalities in Rel-16 may not be completed due to time constrains e.g. 
• Topology adaptation between IAB donors
• Mechanisms for efficient control signaling transmission

Ericsson also provides a good summary in RP-190971 regarding Release 16 IAB and Rel-17 enhancements:

• IAB Rel-16 provide basic support for multi-hop and multi-path relaying. 
• The solution supports 
• QoS prioritization of traffic on the backhaul link
• Flexible resource usage between access and backhaul
• Topology adaptivity in case link failure
• In Rel-17 it would be possible to further evolve the IAB solution targeting increased efficiency and support for new use cases

Meanwhile in the recently concluded RAN#86, AT&T provided a good detailed summary on what enhancements are required for IAB as part of Rel-17 in RP-192709

• Duplexing enhancements
• Multiplexing beyond TDM (FDM/SDM/multi-panel Tx/Rx) including multi-parent scenarios, case 6/7 timing alignment, power control/CLI optimizations
• Topology enhancements
• Mobile IAB: CP/UP split + Group mobility 
• Inter-CU topology adaptation
• Mesh-connectivity between IAB nodes for local control/user plane routing
• User plane enhancements
• Multi-hop scheduling enhancement – exchange of benefit metric between IAB nodes to enable radio-aware multi-hop scheduling to improve throughput performance
• Network Coding
• Study benefits compared to duplication over redundant backhaul routes

We will have to wait and see what makes it into the enhancements and what don't. Meanwhile here is a video from Navid Abedini, Qualcomm from IEEE Sarnoff Symposium, 2019




Related Posts:

• Connectivity Technology Blog: Integrated Access and Backhauling (IAB) - Today and Tomorrow
• 5G Evolution with Matthew Baker, Nokia
• Summary of #CWTEC 2019 Conference: 5G, Satellites & Magic MIMO
• 5G and Fixed-Mobile Convergence (FMC)
• R&S Webinar on LTE-A Pro and evolution to 5G
• Introduction to NR-Light a.k.a. NR-Lite
• An Introduction to Non-Terrestrial Networks (NTN)

Update on UK's Emergency Services Network (ESN) from #BAPCO2019

I have discussed about the UK's Emergency Services Network (ESN) multiple times but I manged to hear about the progress first hand this week. Bryan Clark, ESN Programme Director, Home Office gave a keynote address at BAPCO on Day 2 and the title of his presentation was "2019: The year vision becomes reality"

British APCO or BAPCO Annual Conference and Exhibition 2019 was going to be a big launchpad for the ESN network. The ESN LinkedIn post said "Representatives from ESN and EE will be on hand to discuss coverage and ESN Assure. See an installation of the ESN Gateway solution within a police car, plus a live demonstration showing how ESN coverage can be extended from a vehicle into a building. We’ll also have a ‘Motorola Zone’ where you can watch demos of Kodiak and the ESN self-service portal – and a large touchscreen demo of the Samsung ESN Galaxy"

Bryan started by cracking a joke about people referring to 'ESN' as 'ES When' programme because it has been delayed multiple times. He said straight in the beginning that he going to talk about what the ESN programme is doing now and what comes next.

He started with this short video, embedded below but detailed info available on this LinkedIn post

x

So here is a short summary of the talk:

• There are roughly 350,000 customers of this service
• There are 137 separate organizations that will take advantage of this new this new technology. 
• There are couple of vehicles in the display area (pic on the top and video below) and roughly 50,000 vehicles that need to have a kit
• Over 100 aircraft need to have an air network access that currently isn't there. 
• There are nearly 30 direct suppliers to the program and that doesn't include the whole supply chain through each of those suppliers.
• Looking at the coverage, there is a commitment to providing a signal along half a million (0.5 million) kilometers of roads in England, Scotland & Wales. It extends 12 nautical miles out to sea and 10,000 feet in the air right across England, Scotland & Wales.
• In London alone there are over 400 kilometres of tunnels that were actually almost finished cabling out.
• 300 masts are being built as part of the ESN programme to extend services into remote areas.
• EE has extended their network by adding 700 additional masts. 
• Thousands of special locations will need to have effective access to ESN network
• ESN is a large programme so it's hardly surprising that it's very late. It's Bryan's job over the past 10 months to work out how to get it back on track. 
• People are going through quite a detailed review of where ESN has got to in terms of next steps. 
• The programme now has a very clear and approved plan to complete the technical element of the work, most of it should be done by late summer next year.
• One of the first products, Assure, is a way of testing the effectiveness of the network in the field. 
• A demonstration of Push-To-Talk (PTT) on a 4G network will be demoed within 3 weeks.
• This is the first generation end-to-end solution
• Emergency services is critical national infrastructure so any new solution can only replace the legacy once we are absolutely confident that we've got an effective replacement
• Even though the technical piece is quite challenging, when you compare it to the business change that follows, the technical part looks pretty simple. 
• To ensure that everything works effectively operationally, plans are in place but more detailed plans are going to follow in the coming three to four months.
• Individual components are already being tested in the field
• Programme deployment should start by the end of 2019 in terms of having basically completed laying the core components and a clear plan will be in place for how to test in an operational context. 
• The ESN programme is not only responsible for the replacement solution but also for operations to date based on the Airwave contract with Motorola currently
• The number one priority is to provide critical voice communications of sufficient quality that people can rely on in the field and enable them to move away from the TETRA technology that served them so well. So we aren't going anywhere until we've got rock solid critical voice communications. It's our number one priority, simply because people's lives depend on it.

The following are various videos from the ESN demo area. The Gateway device (which is a mobile small cell) is supplied by Parallel Wireless*.



In case you missed BAPCO, Ken Rehbehn, a very well known Industry Analyst who works as a Principal Analyst at Critical Communications Insights and is also Montgomery County Firefighter/EMT, shared his observations and reflections from conference. Very grateful for his interview which is embedded below



Further Reading:

• Building a new critical communications network that keeps you safe - Bryan Clark, Programme Director, Emergency Services Network

Related posts:

• 3G4G Small Cells Blog: Meshing for BYOC (Bring Your Own Coverage)
• The 3G4G Blog: Quick tutorial on Mobile Network Sharing Options
• The 3G4G Blog: A practical use of MOCN in ESN
• The 3G4G Blog: EE's vision of Ultra-Reliable Emergency Network
• The 3G4G Blog: Update from 3GPP on LTE & 5G Mission Critical Communications

*Full Disclosure: I work for Parallel Wireless as a Senior Director in Strategic Marketing. This blog is maintained in my personal capacity and expresses my own views, not the views of my employer or anyone else. Anyone who knows me well would know this.

Displaying 5G Network Status Icon on Smartphones and Other Devices

A more updated presentation & video on this topic is available on 3G4G '5G Training' page here.

Who thought displaying of network status icon on 5G devices would be so much fun. Typically the network icons are more of:
2G - Gsm, G, G+, E
3G - 3G, H, H+
4G - 4G, 4G+

Back in 2017, Samsung devices started displaying 4G+ icon. Samsung told mybroadband:

that by default its devices require a network to support Category 6 LTE, and for the total combined bandwidth to exceed 20MHz, before they will display the “4G+” icon.

Networks in South Africa frequently don’t have over 20MHz of aggregated bandwidth available, though.

As a result, one network asked Samsung to reduce the combined bandwidth requirement for the 4G+ icon to display to 15MHz, which Samsung approved.

“Samsung’s global policy regarding the display of the LTE/LTE-A/4G/4G+ network icon is that the network icon display is operator-configurable upon official request and Samsung approval,” it said.

The reason this is interesting is because LTE is really 3.9G but generally called 4G. LTE-A is supposed to be 4G because in theory it meets IMT-Advanced criteria. Then we have LTE-Advanced Pro, which is known as 4.5G. While in majority of the operators display 4.5G as 4G or 4G+, couple of operators has decided to become a bit innovative.

AT&T started by updating the network icons of some of their devices to 5GE, which is their way of saying 4.5G. E stands for Evolution. Or as some people joked, it stands for economy (or value) version, as opposed to premium version.

Better example would be that of Tesco Beef (I still remember) 🤣 pic.twitter.com/7yHNDpjDYs

— Zahid Ghadialy (@zahidtg) February 12, 2019

Brazilian operator Claro, decided to use the 4.5G icon but the 5 is much larger font compared to 4 (see the pic above). Some people call this as dishonest attempt by them.

I see a few people asking how can devices decide if they are on 4G or 4.5G. There is no standard procedure for this and is UE specific. One way is to look at RRC messages. If the system information messages contain optional IE's for 3GPP Release-13, then the network supports LTE-A Pro and if the device supports the features for LTE-A Pro, it can display 4.5G or 5GE, etc. Another approach is the optional IEs present in NAS Attach Accept message. As this comes slightly later in the registration process, the device displays 4G first and once the registration is complete, 4.5G. Note there is no requirement from standards point of  view about displaying of the network status indication icon up to 4G/4.5G.

To avoid such confusion in 5G, 3GPP submitted the first Liaison statement S2-175303. In this, 3GPP said:

With this number of System and Radio access options available, one or more new status icons are expected to appear on the User Interface of future (mobile) devices. A user should expect consistency across devices and networks as to what icons actually mean (i.e. what services might be expected when an icon is displayed).

While 3GPP specifications are not expected to define or discuss Service or RAT indicators in the User Interface themselves, 3GPP should provide the necessary tools in EPS and 5GS to enable them. It is therefore necessary to understand the conditions required for displaying these icons and with which granularity so we can identify what information ought to be available in/made available to the device.

SA2 understands that Status Icons related to 5G might be displayed for example on a UE display taking into account all or some combinations of these items (other items may exist):
- Access Restriction Data in subscription (with the potential exception of emergency access); 
- UE CN registration (i.e. is UE EPC- and/or 5GC-registered?);
- UE capabilities; 
- Network capabilities; 
- UE is camping on a cell of NG-RAN supporting NR only, E-UTRA only or, the ability to activate dual connectivity with another RAT (NR or E-UTRA);
- UE is camping on a cell of E-UTRAN (connected to EPC) with the ability to activate dual connectivity with NR as secondary cell;
- UE is in connected mode using NR, E-UTRA (in 5GS) or dual connectivity between E-UTRA and NR.

Given the above, SA2 would like to kindly ask for any feedback from GSMA FNW and NGMN on requirements and granularity for Service indicators and/or RAT indicators related to 5G.

GSMA responded in R2-1713952. 6 cases have been identified (see the first picture on top) :

The configurations consist of the following states and are as described in Table 1:

1. EPS NR NSA (EN-DC) capable UE attached to EPC and currently in IDLE state under or in RRC_connected state connected to E-UTRAN cell not supporting LTE-NR dual connectivity 
2. EPS NR NSA (EN-DC) capable UE attached to EPC and currently in IDLE state under or in RRC_Connected state connected to AND active on LTE for uplink and downlink on only E-UTRAN cell supporting LTE-NR dual connectivity and has not detected NR coverage (i.e. UE is not under NR coverage and/or not configured to make NR measurements)
3. EPS NR NSA (EN-DC) capable UE attached to EPC and currently in RRC_Connected state connected to E-UTRAN cell (supporting dual connectivity) and active on LTE for uplink and downlink only and has detected NR coverage (i.e. UE is under NR coverage and has been configured to make NR measurements) 
4. EPS NR NSA (EN-DC) capable UE attached to EPC and currently in IDLE state under E-UTRAN cell supporting LTE-NR dual connectivity and has detected NR coverage (i.e. UE is under NR coverage and has been configured to make NR measurements)
5. EPS NR NSA (EN-DC) capable UE attached to EPC and currently in RRC_Connected state connected to E-UTRAN cell (supporting dual connectivity) and active on LTE and NR for uplink and/or downlink
6. 5GS capable UE attached to 5GC and currently in IDLE state under or in RRC_Connected state connected to NG-RAN (eLTE (option 5 or 7) or NR (option 2 or 4) cell)

As there is no consensus on a single preferred configuration, it is desirable to make the display of 5G status icon in the UE configurable such that the display of 5G status icon can be made depending on operator preference. 

This proposal by GSMA was noted by 3GPP in R2-1803949.

RAN WG2 would like to inform GSMA and SA2 that, according to GSMA and SA2 recommendations (LSs R2-1713952 and S2-175270, respectively), RAN WG2 introduced 1 bit indication per PLMN called “upperLayerIndication” within LTE SIB 2. 

This bit enables the realization of the configurations based on UE states as per recommendation from GSMA (e.g. RRC_IDLE UE as for State 2 in LS R2-1713952 from GSMA)”. 

For idle mode UEs this is the only mechanism agreed. 

Actions: RAN WG2 would like to ask GSMA and SA2 to take the information above into account. 

Hopefully there will be less confusion when 5G is rolled out about the status icons. In the meantime we might see some more 4.5G icon innovations.

Inside AT&T Towers

A really good video from Mr. Mobile on YouTube on how the cell towers look from inside. Worth your 9:27 mins.



If you found this interesting then you will also like:

• Tutorial: An Introduction to Macrocells & Small Cells
• AT&T Blog: "Providing Connectivity from Inside a Cactus"

5G Architecture Options for Deployments?

I have blogged earlier about the multiple 5G Architecture options that are available (see Deutsche Telekom's presentation & 3G4G video). So I have been wondering what options will be deployed in real networks and when.

The 3GPP webinar highlighted that Option-3 would be the initial focus, followed by Option 2.

Last year AT&T had proposed the following 4 approaches as in the picture above. Recall that Option 1 is the current LTE radio connected to EPC.

ZTE favours Deployment option 2 as can be seen in the slide above

Huawei is favoring Option 3, followed by Option 7 or 2 (& 5)

Going back to the original KDDI presentation, they prefer Option 3, followed by Option 7.

If you are an operator, vendor, analyst, researcher, or anyone with an opinion, what options do you prefer?

Nokia Bell Labs - Future Impossible Series Videos

Picture Source: Cnet

Bell Labs, which has played a significant role in telecoms history and has a very glorious list of achievements created a collection of short films highlighting the brilliant minds who created the invisible nervous system of our society. Some of you may be aware that Bell Labs is now a part of Nokia but was previously part of Alcatel-Lucent, Lucent and AT&T before that.

The playlist with 5 videos is embedded below and short details of the videos follows that.


Video 1: Introduction

Introducing 'Future Impossible', a collection of short films highlighting the brilliant minds who created the invisible nervous system of our society, a fantastic intelligent network of wires and cables undergirding and infiltrating every aspect of modern life.


Video 2: The Shannon Limit

In 1948, father of communications theory Claude Shannon developed the law that dictated just how much information could ever be communicated down any path, anywhere, using any technology. The maximum rate of this transmission would come to be known as the Shannon Limit.  Researchers have spent the following decades trying to achieve this limit and to try to go beyond it.


Video 3: The Many Lives of Copper

In the rush to find the next generation of optical communications, much of our attention has moved away from that old standby, copper cabling. But we already have miles and miles of the stuff under our feet and over our heads. What if instead of laying down new optical fiber cable everywhere, we could figure out a way to breathe new life into copper and drive the digital future that way?


Video 4: The Network of You

In the future, every human will be connected to every other human on the planet by a wireless network. But that’s just the beginning. 

Soon the stuff of modern life will all be part of the network, and it will unlock infinite opportunities for new ways of talking, making and being. The network will be our sixth sense, connecting us to our digital lives. In this film, we ponder that existence and how it is enabled by inventions and technologies developed over the past 30 years, and the innovations that still lie ahead of us.


Video 5: Story of Light

When Alexander Graham Bell discovered that sound could be carried by light, he never could have imagined the millions of written text and audio and video communications that would one day be transmitted around the world every second on a single strand of fiber with the dimensions of a human hair.

Follow the journey of a single text message zipping around the globe at the speed of light, then meet the researchers that have taken up Bell’s charge.


For anyone interested, Wikipedia has a good detailed info on Bell Labs history here.

AT&T Blog: "Providing Connectivity from Inside a Cactus"

A recent AT&T blog post looks at how the fake cactus antennas are manufactured. I also took a closeup of a fake cactus antenna when I went to a Cambridge Wireless Heritage SIG event as can be seen in tweet below.

I also spotted a fake base station at @sciencemuseum 👀📶😎 #CWWH pic.twitter.com/avyiIqte64

— Zahid Ghadialy (@zahidtg) April 29, 2017

The blog says:

To make a stealth site look as real as possible, our teams use several layers of putty and paint. Our goal is to get the texture and color just right, but also ensure it can withstand natural elements – from snowy Colorado to blistering Arizona. 

Tower production takes 6-8 weeks and starts with constructing a particular mold. The molds quickly become 30-foot tall saguaro cacti or 80-foot tall redwood trees.But these aren’t just steel giants. 

The materials that cover the stealth antennas, like paint or faux-leaves, must be radio frequency-friendly. Stealth antennas designed to look like church steeples or water towers are mostly made of fiberglass. This lets the signal from the antennas penetrate through the casing. 

These stealth deployments are just one of the many unique ways we provide coverage to our customers. So take a look outside, your connection may be closer than you think—hidden in plain sight!

This videos gives a good idea


If this is a topic of interest, then have a look at this collection of around 100 antennas:

Antennas: A Collection from 3G4G

See also:

• Different types of Mobile Masts
• The Art of Disguising Cellular Antennas
• Disguising Small Cells in Rural areas

Self-backhauling: Integrated access and backhaul links for 5G

One of the items that was proposed during the 3GPP RAN Plenary #75 held in Dubrovnik, Croatia, was Study on Integrated Access and Backhaul for NR (NR = New Radio). RP-17148 provides more details as follows:

One of the potential technologies targeted to enable future cellular network deployment scenarios and applications is the support for wireless backhaul and relay links enabling flexible and very dense deployment of NR cells without the need for densifying the transport network proportionately. 

Due to the expected larger bandwidth available for NR compared to LTE (e.g. mmWave spectrum) along with the native deployment of massive MIMO or multi-beam systems in NR creates an opportunity to develop and deploy integrated access and backhaul links. This may allow easier deployment of a dense network of self-backhauled NR cells in a more integrated manner by building upon many of the control and data channels/procedures defined for providing access to UEs. An example illustration of a network with such integrated access and backhaul links is shown in Figure 1, where relay nodes (rTRPs) can multiplex access and backhaul links in time, frequency, or space (e.g. beam-based operation).

The operation of the different links may be on the same or different frequencies (also termed ‘in-band’ and ‘out-band’ relays). While efficient support of out-band relays is important for some NR deployment scenarios, it is critically important to understand the requirements of in-band operation which imply tighter interworking with the access links operating on the same frequency to accommodate duplex constraints and avoid/mitigate interference. 

In addition, operating NR systems in mmWave spectrum presents some unique challenges including experiencing severe short-term blocking that cannot be readily mitigated by present RRC-based handover mechanisms due to the larger time-scales required for completion of the procedures compared to short-term blocking. Overcoming short-term blocking in mmWave systems may require fast L2-based switching between rTRPs, much like dynamic point selection, or modified L3-based solutions. The above described need to mitigate short-term blocking for NR operation in mmWave spectrum along with the desire for easier deployment of self-backhauled NR cells creates a need for the development of an integrated framework that allows fast switching of access and backhaul links. Over-the-air (OTA) coordination between rTRPs can also be considered to mitigate interference and support end-to-end route selection and optimization.

The benefits of integrated access and backhaul (IAB) are crucial during network rollout and the initial network growth phase. To leverage these benefits, IAB needs to be available when NR rollout occurs. Consequently, postponing IAB-related work to a later stage may have adverse impact on the timely deployment of NR access.

There is also an interesting presentation on this topic from Interdigital on the 5G Crosshaul group here. I found the following points worth noting:

• This will create a new type of interference (access-backhaul interference) to mitigate and will require sophisticated (complex) scheduling of the channel resources (across two domains, access and backhaul).
• One of the main drivers is Small cells densification calling for cost-effective and low latency backhauling
• The goal would be to maximize efficiency through joint optimization/integration of access and backhaul resources
• The existing approach of Fronthaul using CPRI will not scale for 5G, self-backhaul may be an alternative in the shape of wireless fronthaul

Let me know what you think.

Related Links:

• Backhauling problems driving up deployment costs?

Connecting Rural Scotland using Airmasts and Droneways

This week EE has finally done a press release on what they term as Airmasts (see my blog post here). Back in Nov. last year, Mansoor Hanif, Director of Converged Networks and Innovation BT/EE gave an excellent presentation on connecting rural Scottish Islands using Airmasts and Droneways at the Facebook TIP Summit. Embedded below are the slides and video from that talk.

Driving Connectivity in the Scottish Islands: Droneways and Airmasts from 3G4G

In other related news, AT&T is showing flying COWs (Cell On Wheels) that can transmit LTE signals

Their innovation blog says:

It is designed to beam LTE coverage from the sky to customers on the ground during disasters or big events.
...
Here’s how it works. The drone we tested carries a small cell and antennas. It’s connected to the ground by a thin tether. The tether between the drone and the ground provides a highly secure data connection via fiber and supplies power to the Flying COW, which allows for unlimited flight time.  The Flying COW then uses satellite to transport texts, calls, and data. The Flying COW can operate in extremely remote areas and where wired or wireless infrastructure is not immediately available. Like any drone that we deploy, pilots will monitor and operate the device during use.

Once airborne, the Flying COW provides LTE coverage from the sky to a designated area on the ground.  

Compared to a traditional COW, in certain circumstances, a Flying COW can be easier to deploy due to its small size. We expect it to provide coverage to a larger footprint because it can potentially fly at altitudes over 300 feet— about 500% higher than a traditional COW mast.  

Once operational, the Flying COW could eventually provide coverage to an area up to 40 square miles—about the size of a 100 football fields. We may also deploy multiple Flying COWs to expand the coverage footprint.

Nokia on the other hand has also been showcasing drones and LTE connectivity for public safety at D4G Award event in Dubai

Nokia's Ultra Compact Network provides a standalone LTE network to quickly re-establish connectivity to various mission-critical applications including video-equipped drones. Drones can stream video and other sensor data in real time from the disaster site to a control center, providing inputs such as exact locations where people are stranded and nature of the difficulty of reaching the locations.

Related Posts:

• Flying Small Cells are here...
• Facebook's Attempt to Connect the Unconnected
• An Update from the TIP Summit
• Drone cells are becoming a reality
• When COWs Fly: AT&T Sending LTE Signals from Drones
• Nokia demos drones with LTE connection to conduct rescue operations

Gigabit LTE?

Last year Qualcomm announced the X16 LTE modem that was capable of up to 1Gbps, category 16 in DL and Cat 13 (150 Mbps) in UL. See my last post on UE categories here.

Early January, it announced Snapdragon 835 at CES that looks impressive. Android central says "On the connectivity side of things, there's the Snapdragon X16 LTE modem, which enables Category 16 LTE download speeds that go up to one gigabit per second. For uploads, there's a Category 13 modem that lets you upload at 150MB/sec. For Wi-Fi, Qualcomm is offering an integrated 2x2 802.11ac Wave-2 solution along with an 802.11ad multi-gigabit Wi-Fi module that tops out at 4.6Gb/sec. The 835 will consume up to 60% less power while on Wi-Fi."

Technology purists would know that LTE, which is widely referred to as 4G, was in fact pre-4G or as some preferred to call it, 3.9G. New UE categories were introduced in Rel-10 to make LTE into LTE-Advanced with top speeds of 3Gbps. This way, the ITU requirements for a technology to be considered 4G (IMT-Advanced) was satisfied.

LTE-A was already Gigabit capable in theory but in practice we had been seeing peak speeds of up to 600Mbps until recently. With this off my chest, lets look at what announcements are being made. Before that, you may want to revisit what 4.5G or LTE-Advanced Pro is here.

• Qualcomm, Telstra, Ericsson and NETGEAR Announce World’s First Gigabit Class LTE Mobile Device and Gigabit-Ready Network. Gigabit Class LTE download speeds are achieved through a combination of 3x carrier aggregation, 4x4 MIMO on two aggregated carriers plus 2x2 MIMO on the third carrier, and 256-QAM higher order modulation. 
• TIM in Italy is the first in Europe to launch 4.5G up to 500 Mbps in Rome, Palermo and Sanremo
• Telenet in partnership with ZTE have achieved a download speed of 1.3 Gbps during a demonstration of the ZTE 4.5G new technology. That's four times faster than 4G's maximum download speed. Telenet is the first in Europe to reach this speed in real-life circumstances. 4.5G ZTE technology uses 4x4 MIMO beaming, 3-carrier aggregation, and a QAM 256 modulation.
• AT&T said, "The continued deployment of our 4G LTE-Advanced network remains essential to laying the foundation for our evolution to 5G. In fact, we expect to begin reaching peak theoretical speeds of up to 1 Gbps at some cell sites in 2017. We will continue to densify our wireless network this year through the deployment of small cells and the use of technologies like carrier aggregation, which increases peak data speeds. We’re currently deploying three-way carrier aggregation in select areas, and plan to introduce four-way carrier aggregation as well as LTE-License Assisted Access (LAA) this year."
• T-Mobile USA nearly reached a Gigabit and here is what they say, "we reached nearly 1 Gbps (979 Mbps) on our LTE network in our lab thanks to a combination of three carrier aggregation, 4x4 MIMO and 256 QAM (and an un-released handset)."
• The other US operator Sprint expects to unveil some of its work with 256-QAM and massive MIMO on Sprint’s licensed spectrum that pushes the 1 gbps speed boundary. It’s unclear whether this will include an actual deployment of the technology

So we are going to see a lot of higher speed LTE this year and yes we can call it Gigabit LTE but lets not forget that the criteria for a technology to be real '4G' was that it should be able to do 1Gbps in both DL and UL. Sadly, the UL part is still not going Gigabit anytime soon.

5G New Radio (NR), Architecture options and migration from LTE

You have probably read about the demanding requirements for 5G in many of my blog posts. To meet these demanding requirements a 'next-generation radio' or 'new radio' (NR) will be introduced in time for 5G. We dont know as of yet what air interface, modulation technology, number of antennas, etc. for this NR but this slide above from Qualcomm gives an idea of what technologies will be required for this 5G NR.

The slide above gives a list of design innovations that will be required across diverse services as envisioned by 5G proponents.

It should be mentioned that Rel-10/11/12 version of LTE is referred to as LTE-Advanced and Rel-13/14 is being referred to as LTE-A Pro. Rel-15 will probably have a new name but in various discussions its being referred to as eLTE.

When first phase of 5G arrives in Rel-15, eLTE would be used for access network and EPC will still be used for core network. 5G will use NR and eventually get a new core network, probably in time for phase 2. This is often referred to as next generation core network (NGCN).

The slides below from Deutsche Telekom show their vision of how operators should migrate from eLTE to 5G.

The slides below from AT&T show their vision of LTE to 5G migration.

Eiko Seidel posted the following in 3GPP 5G standards group (i recommend you join if you want to follow technical discussions)


Summary RAN1#86 on New Radio (5G) Gothenburg, Sweden

At this meeting RAN1 delegates presented and discussed numerous evaluation results mainly in the areas of waveforms and channel coding.

Nonetheless RAN1 was not yet prepared to take many technical decisions. Most agreements are still rather general. 

First NR terminology has been defined. For describing time structures mini-slots have been introduced: a mini-slot is the smallest possible scheduling unit and smaller than a slot or a subframe.

Discussions on waveforms favored filtered and windowed OFDM. Channel coding discussions were in favor of LDPC and Turbo codes. But no decisions have been made yet.

Not having taken many decisions at this meeting, RAN1 now is behind its schedule for New Radio.
Hopefully the lag can be made up at two additional NR specific ad hoc meetings that have been scheduled for January and June 2017.

(thanks to my colleague and friend Dr. Frank Kowalewski for writing this short summary!)

Yet another post from Eiko on 3GPP RAN 3 on related topic.

The RAN3 schedule is that in February 2017 recommendations can be made for a protocol architecture.  In the meeting arguments came up by some parties that the work plan is mainly addressing U-Plane architecture and that split of C- and U-plane is not considered sufficiently. The background is that the first step will be dual connectivity with LTE using LTE RRC as control plane and some companies would like to concentrate on this initially. It looks like that a prioritization of features might happen in November timeframe. Beside UP and CP split, also the functional split between the central RAN node and the distributed RAN node is taking place for the cloud RAN fronthaul interface. Besides this, also discussion on the fronthaul interface takes place and it will be interesting to see if RAN3 will take the initiative to standardize a CPRI like interface for 5G. Basically on each of the three interfaces controversial discussion is ongoing.

Yet another basic question is, what is actually considered as a “New 5G RAN”? Is this term limited to a 5G eNB connected to the NG core? Or can it also be also an eLTE eNB with Dual Connectivity to 5G? Must this eLTE eNB be connected to the 5G core or is it already a 5G RAN when connected to the EPC? 

Finally, a slide from Qualcomm on 5G NR standardization & launch.

AT&T's 5G Trials

There was a news recently that "AT&T 5G trials expand, break 10 Gbps throughput". The article said:

Austin, Texas, where RCR Wireless News and Industrial IoT 5G Insights is headquartered, is where AT&T worked with the Federal Communications Commission to get an experimental license to conduct 5G technology trials using spectrum in the 3.4-3.6 GHz, 3.7-4.2 GHz, 14.5-15.35 GHz and 27.5-28.5 GHz bands. The carrier said the testing would be used for “experimental equipment” in support of “potential (5G) multi-gigabyte per second applications for fixed and mobile wireless communication networks at higher transmission rates and lower latency than is currently available,” and supporting voice, video and data.
...
“We’ve seen great results in our 5G lab trials, including reaching speeds above 10 gigabits per second in early tests with Ericsson,” said Tom Keathley, SVP of wireless network architecture and design at AT&T. “Nokia is joining to help us test millimeter wave, which we expect to play a key role in 5G development and deployment. The work coming out of AT&T Labs will pave the way toward future international 5G standards and allow us to deliver these fast 5G speeds and network performance across the U.S.”

While I have seen speed records being set, this will not be of much help in the final standards. Some of you may remember my earlier post where Huawei achieved over 100Gbps in their labs. See here.

A video from recent AT&T mmWave trials is below: