Wednesday 26 August 2020

Multi-SIM Terminology


This new video and presentation looks at the operation and terminology associated with multiple SIMs in mobile cellular devices.

Slides and video embedded below introduces the concept of transceivers, active and standby states and then look at Dual Sim Single & Dual Standby (DSSS / DSDS), Dual SIM Dual Active (DSDA), Triple SIM Triple Standby (TSTS) and finally, Quad SIM Quad Standby (QSQS) in case of four SIM cards.







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Wednesday 19 August 2020

Would 5G NSA undergo Sunset? When?


I have been thinking about the long term evolution of 5G and have now reached the conclusion that it would make sense in the long run to switch off non-standalone 5G. This would of course be only after 5G core has been tested and used extensively. Instead of writing my reasoning, here is a 10 minute video and the corresponding slides.





Let me know what you think in the comments below. If you agree, when do you think is the best time for 5G NSA Sunset?


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Wednesday 12 August 2020

Telecom Services and Data Pricing

With the mobile technology gaining even more subscribers and smartphones becoming common, the telecom services pricing that includes voice, SMS and data is falling. Many operators are now including bundles with generous amounts to satisfy everyone. In many European countries, it is very common to have plans with unlimited everything. 

One of the reports that ITU releases is called "Measuring Digital Development: ICT Price Trends". The latest report for 2019 was released in May this year. The press release says:

On average, prices for mobile-voice, mobile-data and fixed-broadband services are decreasing steadily around the world, and in some countries even dramatically. The reduction in price relative to income is even more dramatic, suggesting that, globally, telecommunication and information and communication technology services are becoming more affordable. However, both trends do not translate into rapidly increasing Internet penetration rates which suggests that there are other barriers to Internet use, concludes ITU in its new statistical report, Measuring Digital Development: ICT Price Trends 2019.

The latest statistics from ITU confirm that affordability may not be the only barrier to Internet uptake, and that other factors such as: 

  • low level of education, 
  • lack of relevant content, 
  • lack of content in local languages, 
  • lack of digital skills, and a 
  • low-quality Internet connection may also prevent effective use. 


Key results​:

  • An entry-level mobile-voice basket remains broadly affordable in most countries. In 70 countries, a low-usage mobile-voice plan was available for less than 1 per cent of gross national income (GNI) per capita, and in a further 37 countries it stood below 2 per cent. Although causality is difficult to prove, price reductions have undoubtedly helped contribute to the rapid rise in the mobile-voice penetration rate, alongside growing competition and better price monitoring and evaluation by regulators.
  • The expansion of bundled services has further reduced prices, as combined data-and-voice baskets are generally less expensive than the sum of the two separate baskets in most markets.
  • Prices have decreased from 2013 to 2019 relative to GNI per capita The global average price of a mobile-data basket of 1.5 GB shrank from 8.4 per cent of GNI per capita in 2013 to 3.2 per cent in 2019, at a compound annual growth rate of almost -15 per cent. When expressed in USD, the global average price of a mobile-data basket of at least 1.5 GB dropped by 7 per cent on average annually between 2013 and 2019.
  • Good progress has been made towards the Broadband Commission for Sustainable Development's target of achieving affordable broadband costing 2-5 per cent of GNI per capita by 2025, but still more remains to be done. There are still nine developing countries and 31 LDCs that have yet to reach the 2 per cent target by 2025.
  • Fixed-broadband packages remain generally more expensive than mobile-data packages (although data allowances are not always directly comparable). Over the past four years, the affordability of fixed broadband has not changed substantially, but advertised download speeds continue to increase.

(click on the image to enlarge)

Some of the results are quite interesting as shown in the image above. The picture on top left shows the different types of packages. The report analyses price data for five key services based on the following five baskets:

  1. mobile-data-and-voice basket (i.e. voice, SMS and mobile data combined) – low consumption (70 minutes, 20 SMSs and 500 MB);
  2. mobile-data-and-voice basket – high consumption (140 minutes, 70 SMSs and 1.5 GB);
  3. mobile-voice (including voice and SMS);
  4. mobile-data;
  5. fixed-broadband.

Chart 1 shows Mobile data and voice baskets in USD for 2019. LDCs stands for Least Developed Countries

Chart 2 shows Mobile data and voice baskets in PPP$, where PPP stands for purchasing power parity. This is defined as basket of goods based comparison approach (see here)

Finally, chart 3 shows Mobile data and voice basket as a % of GNI p.c. GNI stands for gross national income. Expressing prices relative to GNI per capita (GNI p.c.), as a measure of affordability, reveals huge gaps between prices for different levels of development. In developed countries, the price of a low-consumption mobile-data-and-voice basket was equivalent to 1 per cent of GNI p.c. in 2019. In developing countries, this basket cost 7.5 per cent of GNI p.c., while in the LDCs this rose sharply to 17 per cent. For high-consumption mobile-data-and-voice baskets, the differences were even larger.

Source - Visual capitalist. Click link to see complete picture

Visual Capitalist has a nice summary of data prices for 1GB of Mobile data in different parts of the world. A striking trend worth noting is that four out of five of the most expensive countries (Malawi, Benin, Chad, Yemen & Botswana) for mobile data are in Sub-Saharan Africa (SSA).


Cable.co.uk have an interactive map here, that allows you to see prices in different parts of the world. As you would guess, the cheapest data prices in the world is in India.

Finally, eXtensia has a list of data costs in African countries from 2019 here, a lot has changed in the last year so you may have to check if the information you need is correct as of today.

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Thursday 6 August 2020

What about 5G Network Architecture Option 4 (a.k.a. NE-DC) ?

You heard the news about Standalone (SA) 5G network(s)? T-Mobile USA announced this week that "T-Mobile is the first operator in the world to launch a commercial nationwide standalone 5G network". Nationwide is the key word here. Back in February, the Saudi operator STC announced that "stc - Kuwait first to launch 5G E2E SA network in MENA". We will see a lot more announcements about SA 5G this year.


I blogged in detail about the 5G Network Architecture options in this post earlier here. There we looked at the different options in details and typical migration path between the options. Whenever any operator / vendor talks about SA 5G today, they are talking about Option 2. That was back in 2018. Since then, many of the options have lost momentum.

As we all know, the current 5G networks are Non-Standalone or NSA. They are also known as Option 3 or EN-DC. The next evolution is Standalone of SA deployment. It is also known as Option 2. Right now, not many operators or vendors are talking about other options.



While some of the operators have toned down asking for Option 7 (NGEN-DC) & 4 (NE-DC) support, others haven't. Deutsche Telekom is one such operator.


In a webinar on the topic 'The Journey to Standalone 5G' back in March (available on demand here - for DT part, jump to 39 minutes point), Peter Stevens, Principal Engineer, Mobile Access, Deutsche Telekom UK discussed why DT views Option 4 as important for them. In fact if you look at the picture above, you see that they even refer to Option 4 as SA.


One of the motivations from RAN point of view is that because many UEs are not accepting low-low LTE-NR band combinations. So if an operator decided to go with nationwide SA, they have to make the cell sizes smaller than they have to be. This can create coverage gaps with 5G SA. Of course many of the newer features work far better with 5G core (5GC) so option 4 will provide speed benefits of Option 3 NSA without the limitations of 4G EPC.


Standalone without Option 4 can reduce data rates as you can see in the picture above and explained in another of our posts here.


Finally, this last picture summaries the alternatives to Option 4, Dynamic Spectrum Sharing (DSS) or fallback to NSA when 5GC services are not needed. As the slide says, neither of these options is considered a good mainstream alternative to Option 4.

Let me know your thoughts about this in the comments below.

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Saturday 1 August 2020

Artificial Intelligence (AI) / Machine Learning (ML) in 5G Challenge by ITU


ITU is conducting a global ITU AI/ML 5G Challenge on the theme “How to apply ITU's ML architecture in 5G networks". If you don't know the difference between AI & ML, this picture from the old blog post may help.


The ITU website says:

Artificial Intelligence (AI) will be the dominant technology of the future and will impact every corner of society. In particular, AI / ML (machine learning) will shape how communication networks, a lifeline of our society, will be run. Many companies in the ICT sector are exploring how to make best use of AI/ML. ITU has been at the forefront of this endeavour exploring how to best apply AI/ML in future networks including 5G networks. The time is therefore right to bring together the technical community and stakeholders to brainstorm, innovate and solve relevant problems in 5G using AI/ML. Building on its standards work, ITU is conducting a global ITU AI/ML 5G Challenge on the theme “How to apply ITU's ML architecture in 5G networks". 

Participants will be able to solve real world problems, based on standardized technologies developed for ML in 5G networks. Teams will be required to enable, create, train and deploy ML models (such that participants will acquire hands-on experience in AI/ML in areas relevant to 5G). Participation is open to ITU Member States, Sector Members, Associates and Aca​demic Institutions and to any individual from a country that is a member of ITU. ​

There are also some cash prizes, etc. There are various topics with presentation slides & recordings freely available. 

I found the slides from ITU AI/ML in 5G Challenge —”Machine Learning for Wireless LANs + Japan Challenge Introduction” (link) very interesting. There are many other topics including AR / VR / XR, etc, as well.

Have a look at the ITU website here.


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Monday 27 July 2020

Key Technology Aspects of 5G Security by Rohde & Schwarz


The 3G4G page contains a lot of useful papers and links to security here but we have also looked at evolution of security from 4G to 5G here. Rohde & Schwarz has a short 8-minute video in which wireless technology manager, Reiner Stuhlfauth, explains the key technology aspects ensuring 5G security. The video is embedded below.



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Sunday 19 July 2020

Mobile Initiated Connection Only (MICO) mode in 5G System


Mobile Initiated Connection Only (MICO) mode is designed for IoT devices that send small amounts of data and do not need to be paged. An example of this could be a smart bin that sends a message to the waste collection company saying it is 50% full, etc. This way the bin emptying lorry can plan to empty it in the next collection round. Here there is no reason to page the bin as there is no mobile terminated data that would be required.

MICO mode has to be negotiated between the device and AMF in 5GC. A device in MICO mode cannot be paged as it would not listen to paging to conserve battery power. This extreme power saving mode can ensure that the battery can last for very long time, ideally years thereby making this vision of billions of connected IoT devices a reality.


In an earlier post on RRC Inactive state, we looked at NAS states, along with RRC states. When the UE is in MICO mode, the AMF in 5GC will consider the UE to be unreachable when it is in CM-IDLE state. In addition, a periodic registration timer is also allocated to the MICO mode UEs. The UE has to confirm the MICO mode again during registration update.

The video and presentation are embedded below:





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Friday 17 July 2020

A Look into 5G Virtual/Open RAN - Part 7: Change of gNB-CU-UP without Handover

This will be the last part of my series about Virtual/Open RAN signaling procedures. In this final post (although not the last one on this blog) I would like to present a very unique procedure that emerges from the facts of virtualization and automation of the RAN. And again I would like to present the big picture overview of the scenario that is called "Change of gNB-CU UP" (without handover). The full message flow (ladder diagram) can be found in 3GPP 38.401, chapter 8.9.5.

In the same chapter one can read that the trigger point for starting a change of the gNB-CU UP is quite vague. 3GPP writes: "e.g. a measurement report". However, which particular measurement event should trigger such a procedure? Even when looking into the Rel. 16 versions of 3GPP 38.331 (NR RRC) it becomes evident that all measurement events that are not dealing with NR sidelink or V2X connectivity are triggered by changing reference signal strength or rising interference. 

However, in case of a gNB-CU UP change without handover the UE does not move to a different cell. This makes me think - correct me if I am wrong - the true trigger points for this procedures come form a different entity, e.g. from the AI-driven policies and algorithms of the RAN Intelligence Controller (RIC) that is a fundamental element of the Open RAN architecture.


So what is necessary from a signaling perspective to change the gNB-CU UP during an ongoing connection?

There are new transport network resources aka GTP/IP-Tunnels required to steer the user plane traffic to and through the RAN. A new F1-U tunnel is necessary as well a a new NG-U tunnel, because also the user plane traffic between RAN and the UPF in the 5G core network must be exchange using a new route.

When it is clear which new UP transport tunnels need to be established (and which old ones need to be deleted) it is really simple to understand the overall scenario.

A F1AP UE Context Modification procedure is performed to switch the F1-U tunnel. NGAP Path Switch procedure is performed to switch the NG-U tunnel. And an E1AP Bearer Context Modification procedure is the prerequisite, because it delivers the new UL GTP-TEID for the F1-U tunnel as well as the new DL GTP-TEID for the NG-U tunnel.

Unfortunately the authors of 3GPP 38.401 are not very precise when mentioning protocol procedures defined in other specs. Thus, they speak about "bearer modification" when looking at F1AP and "Path Update" for NGAP.

It is not a big deal, but something you just need to know if you want to analyze real-world message flows of this scenario.

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Sunday 12 July 2020

Anritsu Webinar on 'Evolution of 5G from 3GPP Rel-15 to Rel-17 and Testing Challenges'


At the TSG#88e Plenary meetings that ended on 03 July 2020, Release 16 was completed with both the Stage 3 freeze and the ASN.1 and OpenAPI specification freeze being approved. The 3GPP Release-16 page has more details on timelines but they may shift. See at the bottom of this post.

Anritsu have uploaded a short presentation on their channel that I am embedding below. I have skipped the beginning part but of you feel like you want to listen, jump to the beginning.




Meanwhile in the recently concluded TSG#88e Plenary meetings, there is a discussion on some of the timelines for Release-17 and Rel-18 moving. This graph below is from SP-200606.


In another piece of 3GPP news, RAN Working Group 6 (WG6 or RAN6) – responsible for the GERAN and UTRAN radio and protocol work - was formally closed.  No new features but specs will be maintained as necessary, of course.

Finally, here is a short video interview by 3GPP in which Balazs Bertenyi looks back at the recent TSG RAN Plenary e-meeting. He talks about the challenges, about IMT-2020, Rel-16 being just on time & the prospects for Rel-17.

Release 16 - RAN progress from 3GPPlive on Vimeo.


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Monday 6 July 2020

A Technical Introduction to 5G NR RRC Inactive State


I looked at the RRC Inactive state back in 2017, but the standards were not completely defined. In the meantime standards have evolved and commercial 5G networks are rolling out left, right and centre. I made a short technical introduction to the RRC_INACTIVE state, comparing it with the 4G states in RRC and NAS. I also looked at some basic signalling examples and there are lots of relevant references at the end. Video and slides embedded below.






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