Friday 23 October 2020

Positioning Techniques for 5G NR in 3GPP Release-16

I realised that I have not looked at Positioning techniques a lot in our blogs so this one should be a good summary of the latest positioning techniques in 5G.

Qualcomm has a nice short summary hereRelease 16 supports multi-/single-cell and device-based positioning, defining a new positioning reference signal (PRS) used by various 5G positioning techniques such as roundtrip time (RTT), angle of arrival/departure (AoA/AoD), and time difference of arrival (TDOA). Roundtrip time (RTT) based positioning removes the requirement of tight network timing synchronization across nodes (as needed in legacy techniques such as TDOA) and offers additional flexibility in network deployment and maintenance. These techniques are designed to meet initial 5G requirements of 3 and 10 meters for indoor and outdoor use cases, respectively. In Release 17, precise indoor positioning functionality will bring sub-meter accuracy for industrial IoT use cases.

I wrote about the 5G Americas white paper titled, "The 5G Evolution: 3GPP Releases 16-17" highlighting new features in 5G that will define the next phase of 5G network deployments across the globe. The following is from that whitepaper:

Release-15 NR provides support for RAT-independent positioning techniques and Observed Time Difference Of Arrival (OTDOA) on LTE carriers. Release 16 extends NR to provide native positioning support by introducing RAT-dependent positioning schemes. These support regulatory and commercial use cases with more stringent requirements on latency and accuracy of positioning.25 NR enhanced capabilities provide valuable, enhanced location capabilities. Location accuracy and latency of positioning schemes improve by using wide signal bandwidth in FR1 and FR2. Furthermore, new schemes based on angular/spatial domain are developed to mitigate synchronization errors by exploiting massive antenna systems.

The positioning requirements for regulatory (e.g. E911) and commercial applications are described in 3GPP TR 38.855. For regulatory use cases, the following are the minimum performance requirements:

  • Horizontal positioning accuracy better than 50 meters for 80% of the UEs.
  • Vertical positioning accuracy better than 5 meters for 80% of the UEs.
  • End-to-end latency less than 30 seconds.

For commercial use cases, for which the positioning requirements are more stringent, the following are the starting-point performance targets

  • Horizontal positioning accuracy better than 3 meters (indoors) and 10 meters (outdoors) for 80% of the UEs.
  • Vertical positioning accuracy better than 3 meters (indoors and outdoors) for 80% of the UEs.
  • End-to-end latency less than 1 second.

Figure 3.11 above shows the RAT-dependent NR positioning schemes being considered for standardization in Release 16:

  • Downlink time difference of arrival (DL-TDOA): A new reference signal known as the positioning reference signal (PRS) is introduced in Release 16 for the UE to perform downlink reference signal time difference (DL RSTD) measurements for each base station’s PRSs. These measurements are reported to the location server.
  • Uplink time difference of arrival (UL-TDOA): The Release-16 sounding reference signal (SRS) is enhanced to allow each base station to measure the uplink relative time of arrival (UL-RTOA) and report the measurements to the location server.
  • Downlink angle-of-departure (DL-AoD): The UE measures the downlink reference signal receive power (DL RSRP) per beam/gNB. Measurement reports are used to determine the AoD based on UE beam location for each gNB. The location server then uses the AoDs to estimate the UE position.
  • Uplink angle-of-arrival (UL-AOA): The gNB measures the angle-of-arrival based on the beam the UE is located in. Measurement reports are sent to the location server.
  • Multi-cell round trip time (RTT): The gNB and UE perform Rx-Tx time difference measurement for the signal of each cell. The measurement reports from the UE and gNBs are sent to the location server to determine the round trip time of each cell and derive the UE position.
  • Enhanced cell ID (E-CID). This is based on RRM measurements (e.g. DL RSRP) of each gNB at the UE. The measurement reports are sent to the location server.

UE-based measurement reports for positioning:

  • Downlink reference signal reference power (DL RSRP) per beam/gNB
  • Downlink reference signal time difference (DL RSTD)
  • UE RX-TX time difference

gNB-based measurement reports for positioning:

  • Uplink angle-of-arrival (UL-AoA)
  • Uplink reference-signal receive power (UL-RSRP)
  • UL relative time of arrival (UL-RTOA)
  • gNB RX-TX time difference

NR adopts a solution similar to that of LTE LPPa for Broadcast Assistance Data Delivery, which provides support for A-GNSS, RTK and OTDOA positioning methods. PPP-PTK positioning will extend LPP A-GNSS assistance data message based on compact “SSR messages” from QZSS interface specifications. UE-based RAT-dependent DL-only positioning techniques are supported, where the positioning estimation will be done at the UE-based on assistance data provided by the location server.


Rohde&Schwarz have a 5G overview presentation here. This picture from that presentation is a good summary of the 3GPP Release-16 5G NR positioning techniques. This nice short video on "Release 16 Location Based Services Requirements" complements it very well. 


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Friday 16 October 2020

Couple of Tutorials on ETSI NFV MANO


The premises of virtualization is to move physical network functions (PNF in hardware) into software and to design them in a way so that they can be deployed on a NFVI (Network Functions Virtualization Infrastructure, a.k.a. the cloud).

MANagement and Orchestration (MANO) is a key element of the ETSI network functions virtualization (NFV) architecture. MANO is an architectural framework that coordinates network resources for cloud-based applications and the lifecycle management of virtual network functions (VNFs) and network services. As such, it is crucial for ensuring rapid, reliable NFV deployments at scale. MANO includes the following components: the NFV orchestrator (NFVO), the VNF manager (VNFM), and the virtual infrastructure manager (VIM).

NFV MANO is broken up into three functional blocks:

  • NFV Orchestrator: Responsible for onboarding of new network services (NS) and virtual network function (VNF) packages; NS lifecycle management; global resource management; validation and authorization of network functions virtualization infrastructure (NFVI) resource requests.
  • VNF Manager: Oversees lifecycle management of VNF instances; fills the coordination and adaptation role for configuration and event reporting between NFV infrastructure (NFVI) and Element/Network Management Systems.
  • Virtualized Infrastructure Manager (VIM): Controls and manages the NFVI compute, storage, and network resources.

For the NFV MANO architecture to work properly and effectively, it must be integrated with open application program interfaces (APIs) in the existing systems. The MANO layer works with templates for standard VNFs and gives users the power to pick and choose from existing NFVI resources to deploy their platform or element.

Couple of good old tutorials, good as gold, explaining the ETSI NFV MANO concept. The videos are embedded below. The slides from the video are probably not available but there are other slides from ETSI here. If you are new to this, this is a good presentation to start with.

NFV MANO Part 1: Overview and VNF Lifecycle Management: Uwe Rauschenbach | Rapporteur | ETSI NFV ISG covers:

  • ETSI NFV MANO Concepts
  • VNF Lifecycle Management

NFV MANO Part 2: Network Service Lifecycle Management: Jeremy Fuller | Chair, IFA WG | ETSI NFV ISG covers:
  • Network Service Lifecycle Management

If you have any better suggestions for the slides / video, please feel free to add in the comments.

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Saturday 10 October 2020

What is Cloud Native and How is it Transforming the Networks?


Cloud native is talked about so often that it is assumed everyone knows what is means. Before going any further, here is a short introductory tutorial here and video by my Parallel Wireless colleague, Amit Ghadge.  

If instead you prefer a more detailed cloud native tutorial, here is another one from Award Solutions.

Back in June, Johanna Newman, Principal Cloud Transformation Manager, Group Technology Strategy & Architecture at Vodafone spoke at the Cloud Native World with regards to Vodafone's Cloud Native Journey 


Roz Roseboro, a former Heavy Reading analyst who covered the telecom market for nearly 20 years and currently a Consulting Analyst at Light Reading wrote a fantastic summary of that talk here. The talk is embedded below and selective extracts from the Light Reading article as follows:

While vendors were able to deliver some cloud-native applications, there were still problems ensuring interoperability at the application level. This means new integrations were required, and that sent opex skyrocketing.

I was heartened to see that Newman acknowledged that there is a difference between "cloud-ready" and "cloud-native." In the early days, many assumed that if a function was virtualized and could be managed using OpenStack, that the journey was over.

However, it soon became clear that disaggregating those functions into containerized microservices would be critical for CSPs to deploy functions rapidly and automate management and achieve the scalability, flexibility and, most importantly, agility that the cloud promised. Newman said as much, remarking that the jump from virtualized to cloud-native was too big a jump for hardware and software vendors to make.

The process of re-architecting VNFs to containerize them and make them cloud-native is non-trivial, and traditional VNF suppliers have not done so at the pace CSPs would like to see. I reference here my standard chicken and egg analogy: Suppliers will not go through the cost and effort to re-architect their software if there are no networks upon which to deploy them. Likewise, CSPs will not go through the cost and effort to deploy new cloud networks if there is no software ready to run on them. Of course, some newer entrants like Rakuten have been able to be cloud-native out of the gate, demonstrating that the promise can be realized, in the right circumstances.

Newman also discussed the integration challenges – which are not unique to telecom, of course, but loom even larger in their complex, multivendor environments. During my time as a cloud infrastructure analyst, in survey after survey, when asked what the most significant barrier to faster adoption of cloud-native architectures, CSPs consistently ranked integration as the most significant.

Newman spent a little time discussing the work of the Common NFVi Telco Taskforce (CNTT), which is charged with developing a handful of reference architectures that suppliers can then design to which will presumably help mitigate many of these integration challenges, not to mention VNF/CNF life cycle management (LCM) and ongoing operations.

Vodafone requires that all new software be cloud-native – calling it the "Cloud Native Golden Rule." This does not come as a surprise, as many CSPs have similar strategies. What did come as a bit of a surprise, was the notion that software-as-a-service (SaaS) is seen as a viable alternative for consuming telco functions. While the vendor with the SaaS offering may not itself be cloud-native (for example, it could still have hardware dependencies), from Vodafone's point of view, it ends up performing as such, given the lower operational and maintenance costs and flexibility of a SaaS consumption model.

If you have some other fantastic links, videos, resources on this topic, feel free to add in the comments.

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Wednesday 7 October 2020

Understanding the Dual Active Protocol Stack (DAPS) Handover in 5G


In this video I explain the principles and signaling procedures related to the DAPS handover.

The DAPS handover is a new feature for URLLC services defined by 3GPP in Rel. 16.

Friday 2 October 2020

5G Enhanced URLLC (eURLLC)

One of the interesting features of 5G is Ultra-Reliability and Low-Latency Communication or URLLC. It has been enhanced as part of 3GPP Release-16. A summary of the changes in eURLLC can be seen in the picture above. 


This ATIS webinar that I blogged about last week covered this topic as well. For example L1/L2 changes have been summarised nicely in this Qualcomm slide above while the slide from Intel speaker below looks at redundant transmission and session continuity.

Redundant transmission in the user plane is an extremely useful feature, especially if the packets are mission critical and have to reach from the source to their destination in a guaranteed time / reliability.

Dual connectivity will enable this redundant path when required to meet a guaranteed reliability. 

Here is a short video from the training company Mpirical, explaining the the 5G eURLLC feature: 

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Sunday 27 September 2020

ATIS Webinar on '5G Standards Developments in 3GPP Release 16 and Beyond'

3GPP Organizational Partner, ATIS (Alliance for Telecommunications Industry Solutions), recently delivered a webinar (video & slides below) titled "5G Standards Developments in 3GPP Release 16 and Beyond". 

3GPP News details:

An expert panel brings you up-to-speed on the current state of 5G standardization. The webinar delivers a broad overview of 3GPP's work and introduces some of the key technology elements. It is suitable for people in technical roles and technical executives who want to understand the current state of 5G standardization.

In Release 16, 3GPP delivered important updates to 5G specifications to broaden their range of commercial applications and improve the efficiency of networks. 3GPP is now further enhancing 5G in Release 17 and starting to plan Release 18. This webinar provides an up-to-date view of the completed 3GPP Release 16 work with a particular focus on how the work is expanding capabilities of 5G and enhancing the technical performance of the mobile system. It also looks ahead to future 3GPP deliverables and their use cases.


The webinar features, Iain Sharp, Principal Technologist at ATIS (Moderator), Greg Schumacher, Global Standards at T-Mobile USA and 3GPP SA and SA1 Vice Chairman, Puneet Jain, Director of Technical Standards at Intel and 3GPP SA2 Chairman and Wanshi Chen, Senior Director, Technology at Qualcomm and 3GPP RAN1 Chairman


Many interesting topics have been covered including the updates on mMTC and URLLC. 


There is also details about new features coming in 3GPP Release-17 and an early look at what 3GPP Release-18 might include, as can be seen in the picture above.

Sunday 20 September 2020

Reliance Jio and 5G Network Architecture Option 6


Last week I read about Jio looking at 5G Network Architecture Option 6. There were also a few discussions on Twitter with users sounding a bit confused. So here is my attempt to explain what is Option 6. Video and slides embedded below. 

You can also see this original video where Satish Jamadagni, Vice President - Network Planning Engineering, Head of Standards at Reliance Jio talks about the need for Option 6. 

Feel free to leave your thoughts in the comments below.

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Thursday 10 September 2020

Interfacing HSS and UDM in 5GS with UDICOM (a.k.a NU1 / Nhss)

Back in 2012, we were talking about migration from HLR to HSS. Now we are discussing how to interface HSS to the UDM (Unified Data Management in 5G Core).


In the recent 5G World event, Richard Band, Head of 5G Core, HPE talked about 4G to 5G transition planning. During the talk he mentioned about UDICOM, which is the Standardised new interface between HSS and UDM as defined in 3GPP TS 23.632.


UDICOM allows operators to deploy separate HSS and UDM, even from different vendors. Supported features include:
  • Authentication
  • Single Registration Handover
  • IMS
  • SMS over NAS
3GPP TS 23.632 (Technical Specification Group Core Network and Terminals; User data interworking, coexistence and migration; Stage 2; Release 16) does not use the term UDICOM. It does however describe the interface details, system architecture, system procedures and network function service procedures of UDM-HSS interface.

As can be seen in the picture above, the following reference points are realized by service-based interfaces:
NU1: Reference point between the HSS and the UDM.
NU2: Reference point between the HSS and the 5GS-UDR.

The following Service based interfaces are defined for direct UDM-HSS interworking:
Nudm: Service-based interface exhibited by UDM.
Nhss: Service-based interface exhibited by HSS.

I am not going in more details here but anyone wanting to learn more about the interface should start with 3GPP TS 23.632.

Finally, this talk from HP Enterprise below provides more details of UDICOM.



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Thursday 3 September 2020

Two Types of SMS in 5G


GSMA recently published updated "5G Implementation Guidelines: SA Option 2". It explains the two types of SMS in 5G, the same way there were 2 types of SMS in LTE.

Within 5GC, SMS Function (SMSF) supports SMS over NAS (SMSoNAS) defined in 3GPP TS 23.501. Besides, SMSoIP can also be considered as IMS based SMS solution under 5G network. SMSoIP can be deployed simultaneously with voice service over IMS to provide both voice and short message service. It is recommended to use SMSoNAS solution if voice services over IMS is not supported or for a 5G data card/Machine Type Communications (MTC)/Non-IMS device without voice service. The network architecture of SMSoIP and SMSoNAS is shown in Figure.
Mpirical explains it in the video as embedded below:


You may also find "5G SMS is Very Real and Here to Stay" by William Dudley useful. It covers a lot of technical details and signalling. It's available here.

Related  posts:

Friday 28 August 2020

3GPP MDT - How it works and what is new in Rel. 16


Today I launched my first video. It is about the 3GPP Minimization of Drive Test (MDT) and what is new for this feature in Rel. 16 / 5G networks.

This video explains the overall concept of the MDT feature defined by 3GPP. Individual signaling procedures for immediate and logged mode MDT reporting are presented as well as the latest enhancements for 5G networks defined in 3GPP Release 16.

Enjoy watching

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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