Showing posts with label 3GPP. Show all posts
Showing posts with label 3GPP. Show all posts

Thursday, 21 March 2019

Update from 3GPP on LTE & 5G Mission Critical Communications


Adrian Scrase, CTO of ETSI & Head of MCC, 3GPP presented an update at BAPCO / CCE 2019 on Public Safety LTE and 5G. His presentation is embedded below.

There has been quite a progress in this area since I wrote my last post on Release-14 here.
This is the list of features that are planned for Release-16. There is also an update on Satellite communications but I will look at it separately in another post. Here are the slides:



The presentation can be directly downloaded from 3GPP website here.

Related posts:

Thursday, 7 March 2019

Updated 5G Terminology Presentation (Feb 2019)


I made this video before MWC with the intention to educate the attendees about the various architecture options and 5G terminologies being discussed. As always, happy to get feedback on what can be done better. Slides followed by video below.







Complete list of our training resources are available on 3G4G page here.

Sunday, 17 February 2019

Displaying 5G Network Status Icon on Smartphones and Other Devices

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.


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.

Monday, 29 October 2018

Overview 3GPP 5G NR Physical Layer

3GPP held a workshop on 5G NR submission towards IMT-2020 last week. You can access all the agenda, documents, etc. on the 3GPP website here. You can also get a combined version of all presentations from the 3G4G website here. I also wrote a slightly detailed article on this workshop on 3G4G website here.

One of the presentations on 'Physical layer structure, numerology and frame structure, NR spectrum utilization mechanism 3GPP 5G NR submission towards IMT-2020' by Havish Koorapaty, Ericsson is a good introductory material on 5G New Radio (NR) Physical Layer. It is embedded below (thanks to Eiko Seidel for sharing) and the PDF can be downloaded from slideshare or 3G4G website here.



Related Links:

Monday, 24 September 2018

5G New Radio Standards and other Presentations


A recent Cambridge Wireless event 'Radio technology for 5G – making it work' was an excellent event where all speakers delivered an interesting and insightful presentation. These presentations are all available to view and download for everyone for a limited time here.

I blogged about the base station antennas last week but there are other couple of presentations that stood out for me.


The first was an excellent presentation from Sylvia Lu from u-Blox, also my fellow CW Board Member. Her talk covered variety of topics including IoT, IIoT, LTE-V2X and Cellular positioning, including 5G NR Positioning Trend. The presentation is embedded below and available to download from Slideshare





The other presentation on 5G NR was one from Yinan Qi of Samsung R&D. His presentation looked at variety of topics, mainly Layer 1 including Massive MIMO, Beamforming, Beam Management, Bandwidth Part, Reference Signals, Phase noise, etc. His presentation is embedded below and can be downloaded from SlideShare.




Related Posts:

Friday, 22 June 2018

5G and IoT Security Update from ETSI Security Week 2018

ETSI Security Week 2018 (link) was held at ETSI's Headquarters in Sophia Antipolis, South of France last week. It covered wide variety of topics including 5G, IoT, Cybersecurity, Middlebox, Distributed Ledger Technology (DLT), etc. As 5G and IoT is of interest to the readers of this blog, I am providing links to the presentations so anyone interested can check them out at leisure.


Before we look at the presentations, what exactly was the point of looking at 5G Security? Here is an explanation from ETSI:

5G phase 1 specifications are now done, and the world is preparing for the arrival of 5G networks. A major design goal of 5G is a high degree of flexibility to better cater for specific needs of actors from outside the telecom sector (e.g. automotive industry, mission-critical organisations). During this workshop, we will review how well 5G networks can provide security for different trust models, security policies, and deployment scenarios – not least for ongoing threats in the IoT world. 5G provides higher flexibility than legacy networks by network slicing and virtualization of functions. The workshop aims to discuss how network slicing could help in fulfilling needs for different users of 5G networks.

5G will allow the use of different authentication methods. This raises many interesting questions. How are these authentication methods supported in devices via the new secure element defined in ETSI SCP, or vendor-specific concepts? How can mission-critical and low-cost IoT use cases coexist side-by-side on the same network?

The 5G promise of higher flexibility is also delivered via its Service-Based Architecture (SBA). SBA provides open 3rd party interfaces to support new business models which allow direct impact on network functions. Another consequence of SBA is a paradigm shift for inter-operator networks: modern APIs will replace legacy signaling protocols between networks. What are the relevant security measures to protect the SBA and all parties involved? What is the role of international carrier networks like IPX in 5G?

Event Objectives
The workshop intends to:

  • Gather different actors involved in the development of 5G, not only telecom, and discuss together how all their views have shaped phase 1 of 5G, to understand how security requirements were met, and what challenges remain;
  • Discuss slicing as a means to implement separate security policies and compartments for independent tenants on the same infrastructure;
  • Give an update of what is happening in 3GPP 5G security;
  • Explain to IoT players what 5G security can (and cannot) do for them, including risks and opportunities related to alternative access credentials;
  • Understand stakeholders' (PMNs, carriers, GSMA, vendors) needs to make SBA both secure and successful. How can SBA tackle existing issues in interconnect networks like fraud, tracking, privacy breaches;
  • Allow vendors to present interesting proposals for open security questions in 5G: secure credential store, firewalling SBA's RESTful APIs;
  • Debate about hot topics such as: IoT security, Slicing security, Privacy, Secure storage and processing and Security of the interconnection network.


So here are the relevant presentations:

Session 1: Input to 5G: Views from Different Stakeholders
Session Chair: Bengt Sahlin, Ericsson

Hardening a Mission Critical Service Using 5G, Peter Haigh, NCSC

Security in the Automotive Electronics Area, Alexios Lekidis, SecurityMatters

Integrating the SIM (iUICC), Adrian Escott, QUALCOMM

Smart Secure Platform, Klaus Vedder, Giesecke & Devrient, ETSI SCP Chairman

Network Slicing, Anne-Marie Praden, Gemalto

Don't build on Sand: Validating the Security Requirements of NFV Infrastructure to Confidently Run Slices, Nicolas Thomas, Fortinet

5G Enhancements to Non-3GPP Access Security, Andreas Kunz, Lenovo

Security and Privacy of IoT in 5G, Marcus Wong, Huawei Technologies

ITU-T activities and Action Plan on 5G Security, Yang Xiaoya, ITU-T SG17

Wrap up: 5G Overview from 3GPP SA3 Perspective and What is There to Be Done for Phase 2, Sander Kievit, TNO


Session 2: Security in 5G Inter-Network Signalling
Session Chair: Stefan Schroeder, T-Systems

Presentation on SBA: Introduction of the Topic and Current Status in SA3, Stefan Schroeder, T-Systems

5G Inter-PLMN Security: The Trade-off Between Security and the Existing IPX Business Model, Ewout Pronk, KPN on behalf of GSMA Diameter End to End Security Subgroup

Secure Interworking Between Networks in 5G Service Based Architecture, Silke Holtmanns, Nokia Bell Labs

Security Best Practises using RESTful APIs, Sven Walther, CA Technologies

Identifying and Managing the Issues around 5G Interconnect Security, Stephen Buck, Evolved Intelligence

Zero Trust Security Posture in 5G Architecture, Galina Pildush, Palo Alto Networks (Missing)


Session 1 & 2 Workshop Wrap up: 5G Phase 1 Conclusions and Outlook Towards Phase 2 - Stefan Schroeder, T-Systems and Bengt Sahlin, Ericsson


Session 5: Benefits and Challenges of 5G and IoT From a Security Perspective
Session Chair: Arthur van der Wees, Arthur's Legal

Setting the Scene, Franck Boissière, European Commission

ENISA's View on Security Implications of IoT and 5G, Apostolos Malatras, ENISA

Smart City Aspects, Bram Reinders, Institute for Future of Living

The Network Operators Perspective on IoT Security, Ian Smith, GSMA


Related Links:

Sunday, 25 March 2018

5G Security Updates - March 2018


Its been a while since I wrote about 5G security in this fast changing 5G world. If you are new to 3GPP security, you may want to start with my tutorial here.

3GPP SA3 Chairman, Anand R. Prasad recently mentioned in his LinkedIn post:

5G security specification finalized! Paving path for new business & worry less connected technology use.

3GPP SA3 delegates worked long hours diligently to conclude the specification for 5G security standard during 26 Feb.-2 Mar. Several obstacles were overcome by focussed effort of individuals & companies from around the globe. Thanks and congrats to everyone!

All together 1000s of hours of work with millions of miles of travel were spent in 1 week to get the work done. This took 8 meetings (kicked off Feb. 2017) numerous on-line meetings and conference calls.

Excited to declare that this tremendous effort led to timely completion of 5G security specification (TS 33.501) providing secure services to everyone and everything!

The latest version of specs is on 3GPP website here.

ITU also held a workshop on 5G Security in Geneva, Switzerland on 19 March 2018 (link). There were quite a few interesting presentations. Below are some slides that caught my attention.

The picture in the tweet above from China Mobile summarises the major 5G security issues very well. 5G security is going to be far more challenging than previous generations.

The presentation by Haiguang Wang, Huawei contained a lot of good technical information. The picture at the top is from that presentation and highlights the difference between 4G & 5G Security Architecture.


New entities have been introduced to make 5G more open.


EPS-AKA vs 5G-AKA (AKA = Authentication and Key Agreement) for trusted nodes


EAP-AKA' for untrusted nodes.


Slice security is an important topic that multiple speakers touched upon and I think it would continue to be discussed for a foreseeable future.

Dr. Stan Wing S. Wong from King’s College London has some good slides on 5G security issues arising out of Multi-Tenancy and Multi-Network Slicing.

Peter Schneider from Nokia-Bell Labs had good slides on 5G Security Overview for Programmable Cloud-Based Mobile Networks

Sander Kievit from TNO, a regular participant of working group SA3 of 3GPP on behalf of the Dutch operator KPN presented a view from 3GPP SA3 on the Security work item progress (slides). The slide above highlights the changes in 5G key hierarchy.

The ITU 5G Security Workshop Outcomes is available here.

ETSI Security Week 2018 will be held 11-15 June 2018. 5G security/privacy is one of the topics.

There is also 5GPPP Workshop on 5G Networks Security (5G-NS 2018), being held in Hamburg, Germany on August 27-30, 2018.

In the meantime, please feel free to add your comments & suggestions below.


Related Posts & Further Reading:

Tuesday, 6 February 2018

QUIC - Possibly in 5G, 3GPP Release-16


Over the last year or so, I have heard quite a few discussions and read many articles around why QUIC is so good and why we will replace TCP with QUIC (Quick UDP Internet Connection). One such article talking about QUIC benefits says:

QUIC was initially developed by Google as an alternative transport protocol to shorten the time it takes to set up a connection. Google wanted to take benefits of the work done with SPDY, another protocol developed by Google that became the basis for the HTTP/2 standard, into a transport protocol with faster connection setup time and built-in security. HTTP/2 over TCP multiplexes and pipelines requests over one connection but a single packet loss and retransmission packet causes Head-of-Line Blocking (HOLB) for the resources that were being downloaded in parallel. QUIC overcomes the shortcomings of multiplexed streams by removing HOLB. QUIC was created with HTTP/2 as the primary application protocol and optimizes HTTP/2 semantics.


What makes QUIC interesting is that it is built on top of UDP rather than TCP. As such, the time to get a secure connection running is shorter using QUIC because packet loss in a particular stream does not affect the other streams on the connection. This results in successfully retrieving multiple objects in parallel, even when some packets are lost on a different stream. Since QUIC is implemented in the userspace compared to TCP, which is implemented in the kernel, QUIC allows developers the flexibility of improving congestion control over time, since it can be optimized and better replaced compared to kernel upgrades (for example, apps and browsers update more often than OS updates).

Georg Mayer mentioned about QUIC in a recent discussion with Telecom TV. His interview is embedded below. Jump to 5:25 for QUIC part only

Georg Mayer, 3GPP CT work on 5G from 3GPPlive on Vimeo.

Below are some good references about QUIC in case you want to study further.

Tuesday, 16 January 2018

3GPP-VRIF workshop on Virtual Reality Ecosystem & Standards in 5G

Its been a year since I last posted about Augmented / Virtual Reality Requirements for 5G. The topic of Virtual Reality has since made good progress for 5G. There are 2 technical reports that is looking at VR specifically. They are:

The second one is work in progress though. 

Anyway, back in Dec. 3GPP and Virtual Reality Industry Forum (VRIF) held a workshop on VR Ecosystem & Standards. All the materials, including agenda is available here. The final report is not there yet but I assume that there will be a press release when the report is published.

While there are some interesting presentations, here is what I found interesting:

From presentation by Gordon Castle, Head of Strategy Development, Ericsson





From presentation by Martin Renschler, Senior Director Technology, Qualcomm


For anyone wanting to learn more about 6 degrees of freedom (6- DoF), see this Wikipedia entry. According to the Nokia presentation, Facebook’s marketing people call this “6DOF;” the engineers at MPEG call it “3DOF+.”
XR is 'cross reality', which is any hardware that combines aspects of AR, MR and VR; such as Google Tango.

From presentation by Devon Copley, Former Head of Product, Nokia Ozo VR Platform
Some good stuff in the pres.

From presentation by Youngkwon Lim, Samsung Research America; the presentation provided a link to a recent YouTube video on this presentation. I really liked it so I am embedding that here:



Finally, from presentation by Gilles Teniou, SA4 Vice chairman - Video SWG chairman, 3GPP





You can check and download all the presentations here.

Further Reading:

Sunday, 7 January 2018

Satellites & Non-terrestrial networks (NTN) in 5G


Satellites has been an area of interest of mine for a while as some of you know that I used to work as Satellite Applications & Services Programme manager at techUK. I have written about how I see satellites complementing the mobile networks here and here.

Its good to see that there is some activity in 3GPP going on about satellites & Non-terrestrial networks (NTN) in 5G. While there are some obvious roles that satellites can play (see pic above), the 5G work is looking to cover a lot more topics in details.

3GPP TR 38.913: Study on scenarios and requirements for next generation access technologies looks at 12 different scenarios, the ones relevant to this topic ate Air to ground, Light aircraft and Satellite to terrestrial.
3GPP TR 38.811: Study on New Radio (NR) to support non terrestrial networks (Release 15) covers this topic a bit more in detail. From looking at how satellites and other aerial networks work in general, it looks at the different NTN architecture options as can be seen above.
People looking to study this area in detail should probably start looking at this TR first.

3GPP also released a news item on this topic last week. It also refers to the above TR and a new one for Release 16. The following from 3GPP news:

The roles and benefits of satellites in 5G have been studied in 3GPP Release 14, leading to the specific requirement to support satellite access being captured in TS 22.261 - “Service requirements for next generation new services and markets; Stage 1”, recognizing the added value that satellite coverage brings, as part of the mix of access technologies for 5G, especially for mission critical and industrial applications where ubiquitous coverage is crucial.

Satellites refer to Spaceborne vehicles in Low Earth Orbits (LEO), Medium Earth Orbits (MEO), Geostationary Earth Orbit (GEO) or in Highly Elliptical Orbits (HEO).

Beyond satellites, Non-terrestrial networks (NTN) refer to networks, or segments of networks, using an airborne or spaceborne vehicle for transmission. Airborne vehicles refer to High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) - including tethered UAS, Lighter than Air UAS and Heavier than Air UAS - all operating at altitude; typically between 8 and 50 km, quasi-stationary.

These Non-terrestrial networks feature in TSG RAN’s TR 38.811 “Study on NR to support non-terrestrial networks”. They will:
  • Help foster the 5G service roll out in un-served or underserved areas to upgrade the performance of terrestrial networks
  • Reinforce service reliability by providing service continuity for user equipment or for moving platforms (e.g. passenger vehicles-aircraft, ships, high speed trains, buses)
  • Increase service availability everywhere; especially for critical communications, future railway/maritime/aeronautical communications
  • Enable 5G network scalability through the provision of efficient multicast/broadcast resources for data delivery towards the network edges or even directly to the user equipment


The objective of TR 38.811 is to study channel models, to define the deployment scenarios as well as the related system parameters and to identify and assess potential key impact areas on the NR. In a second phase, solutions for the identified key impacts on RAN protocols/architecture will be evaluated and defined.

A second study item, the “Study on using Satellite Access in 5G” is being addressed in Working Group SA1.  It shall lead to the delivery of the corresponding Technical Report TR 22.822 as part of Release 16.

This study will identify use cases for the provision of services when considering the integration of 5G satellite-based access components in the 5G system. When addressing the integration of (a) satellite component(s), use cases will identify new potential requirements for 5G systems addressing:
  • The associated identification of existing / planned services and the corresponding modified or new requirements
  • The associated identification of new services and the corresponding requirements
  • The requirements on set-up / configuration / maintenance of the features of UE’s when using satellite components related features as well for other components from the 5G system
  • Regulatory requirements when moving to (or from) satellite from (or to) terrestrial networks


You may also like my presentation / video on 'Connectivity on Planes'.

Friday, 22 December 2017

The small detail about 5G you may have missed...


While going through the latest issue of CW Journal, I came across this article from Moray Rumney, Lead Technologist, Keysight. It highlights an interesting point that I missed out earlier that 5G also includes all LTE specifications from Release 15 onwards.

I reached out to our CW resident 3GPP standards expert Sylvia Lu to clarify and received more details.
There is a whole lot of detail available in RP-172789.zip. Here RIT stands for Radio Interface Technology and SRIT for Set of RIT.

In fact at Sylvia clarified, NB-IoT and Cat-M will also be part of the initial IMT-2020 submissions early next year. Thanks Sylvia.


There is also this nice presentation by Huawei in ITU (here) that describes Requirements, Evaluation Criteria and Submission Templates for the development of IMT-2020. It is very helpful in understanding the process.

Coming back to the question I have often asked (see here for example),
1. What features are needed for operator to say they have deployed 5G, and
2. How many sites / coverage area needed to claim 5G rollout

With LTE Release-15 being part of 5G, I think it has just become easy for operators to claim they have 5G.

What do you think?

Monday, 18 December 2017

Control and User Plane Separation of EPC nodes (CUPS) in 3GPP Release-14


One of the items in 3GPP Rel-14 is Control and User Plane Separation of EPC nodes (CUPS). I have made a video explaining this concept that is embedded below.

In 3G networks (just considering PS domain), the SGSN and GGSN handles the control plane that is responsible for signalling as well as the user plane which is responsible for the user data. This is not a very efficient approach for deployment.

You can have networks that have a lot of signalling (remember signaling storm?) due to a lot of smartphone users but not necessarily consuming a lot of data (mainly due to price reasons). On the other hand you can have networks where there is not a lot of signalling but lot of data consumption. An example of this would be lots of data dongles or MiFi devices where users are also consuming a lot of data, because it’s cheap.

To cater for these different scenarios, the control plane and user plane was separated to an extent in the Evolved Packet Core (EPC). MME handles the control plane signalling while S-GW & P-GW handles the user plane

CUPS goes one step further by separating control & user plane from S-GW, P-GW & TDF. TDF is Traffic Detection Function which was introduced together with Sd reference point as means for traffic management in the Release 11. The Sd reference point is used for Deep Packet Inspections (DPI) purposes. TDF also provides the operators with the opportunity to capitalize on analytics for traffic optimization, charging and content manipulation and it works very closely with Policy and charging rules function, PCRF.

As mentioned, CUPS provides the architecture enhancements for the separation of S-GW, P-GW & TDF functionality in the EPC. This enables flexible network deployment and operation, by using either distributed or centralized deployment. It also allows independent scaling between control plane and user plane functions - while not affecting the functionality of the existing nodes subject to this split.

As the 3GPP article mentions, CUPS allows for:
  • Reducing Latency on application service, e.g. by selecting User plane nodes which are closer to the RAN or more appropriate for the intended UE usage type without increasing the number of control plane nodes.
  • Supporting Increase of Data Traffic, by enabling to add user plane nodes without changing the number of SGW-C, PGW-C and TDF-C in the network.
  • Locating and Scaling the CP and UP resources of the EPC nodes independently.
  • Independent evolution of the CP and UP functions.
  • Enabling Software Defined Networking to deliver user plane data more efficiently.

The following high-level principles were also adopted for the CUPS:
  • The CP function terminates the Control Plane protocols: GTP-C, Diameter (Gx, Gy, Gz).
  • A CP function can interface multiple UP functions, and a UP function can be shared by multiple CP functions.
  • An UE is served by a single SGW-CP but multiple SGW-UPs can be selected for different PDN connections. A user plane data packet may traverse multiple UP functions.
  • The CP function controls the processing of the packets in the UP function by provisioning a set of rules in Sx sessions, i.e. Packet Detection Rules for packets inspection, Forwarding Action Rules for packets handling (e.g. forward, duplicate, buffer, drop), Qos Enforcement Rules to enforce QoS policing on the packets, Usage Reporting Rules for measuring the traffic usage.
  • All the 3GPP features impacting the UP function (PCC, Charging, Lawful Interception, etc) are supported, while the UP function is designed as much as possible 3GPP agnostic. For example, the UPF is not aware of bearer concept.
  • Charging and Usage Monitoring are supported by instructing the UP function to measure and report traffic usage, using Usage Reporting Rule(s). No impact is expected to OFCS, OCS and the PCRF.
  • The CP or UP function is responsible for GTP-u F-TEID allocation.
  • A legacy SGW, PGW and TDF can be replaced by a split node without effecting connected legacy nodes.
CUPS forms the basis of EPC architecture evolution for Service-Based Architecture for 5G Core Networks. More in another post soon.

A short video on CUPS below, slides available here.



Further reading:


Tuesday, 5 December 2017

Summary of 3GPP Release-14 Work Items


With all focus on 5G (Release-15), looks like Rel-14 has been feeling a bit neglected. There are some important updates though as it lays foundation for other services.

3GPP used to maintain Release Descriptions here for all different releases but have stopped doing that since 2014. For Release-14, a new document "3GPP TR 21.914: Release 14 Description; Summary of Rel-14 Work Items" is now available here.

An executive summary from the document:

Release 14 focusses on the following items:
  • Improving the Mission Critical aspects, in particular with the introduction of Video and Data services
  • Introducing the Vehicle-to-Everything (V2X) aspects, in particular the Vehicle-to-Vehicle (V2)
  • Improving the Cellular Internet of Things (CIoT) aspects, with 2G, 3G and 4G support of Machine-Type of Communications (MTC)
  • Improving the radio interface, in particular by enhancing the aspects related to coordination with WLAN and unlicensed spectrum
  • A set of uncorrelated improvements, e.g. on Voice over LTE (VoLTE), IMS, Location reporting.


The continuation of this document provides an exhaustive view of all the items specified by 3GPP in Release 14.

I have blogged about the Mission Critical Communications here. 3GPP has also done a webinar on this topic which can be viewed here. I like this slide below that summarizes features in different releases.

Then there are quite a few new features and enhancements for V2X. I have blogged about sidelink and its proposed extensions here.

From the document:

The Work Item on “Architecture enhancements for LTE support of V2X services (V2XARC)”, driven by SA WG2, specifies the V2X architectures, functional entities involved for V2X communication, interfaces, provisioned parameters and procedures in TS 23.285.
Figure above depicts an overall architecture for V2X communication. V2X Control Function is the logical function defined for network related actions required for V2X and performs authorization and provisioning of necessary parameters for V2X communication to the UE via V3 interface.

A UE can send V2X messages over PC5 interface by using network scheduled operation mode (i.e. centralized scheduling) and UE autonomous resources selection mode (i.e. distributed scheduling) when the UE is "served by E-UTRAN" while a UE can send V2X messages over PC5 interface only by using UE autonomous resources selection mode when the UE is "not served by E-UTRAN". 

Both IP based and non-IP based V2X messages over PC5 are supported. For IP based V2X messages over PC5, only IPv6 is used. PPPP (ProSe Per-Packet Priority) reflecting priority and latency for V2X message is applied to schedule the transmission of V2X message over PC5.

A UE can send V2X messages over LTE-Uu interface destined to a locally relevant V2X Application Server, and the V2X Application Server delivers the V2X messages to the UE(s) in a target area using unicast delivery and/or MBMS (Multimedia Broadcast/Multicast Service) delivery.

Both IP based and non-IP based V2X messages are supported for V2X communication over LTE-Uu. In order to transmit non-IP based V2X messages over LTE-Uu, the UE encapsulates the V2X messages in IP packets.

For latency improvements for MBMS, localized MBMS can be considered for localized routing of V2X messages destined to UEs.

For V2X communication over LTE-Uu interface, the V2X messages can be delivered via Non-GBR bearer (i.e. an IP transmission path with no reserved bitrate resources) as well as GBR bearer (i.e. an IP transmission path with reserved (guaranteed) bitrate resources). In order to meet the latency requirement for V2X message delivery, the following standardized QCI (QoS Class Identifier) values defined in TS 23.203 can be used:
  • QCI 3 (GBR bearer) and QCI 79 (Non-GBR bearer) can be used for the unicast delivery of V2X messages.
  • QCI 75 (GBR bearer) is only used for the delivery of V2X messages over MBMS bearers. 


There are updates to cellular IoT (CIot) which I have blogged about here.

There are some other interesting topic that are enhanced as part of Release14. Here are some of them:
  • S8 Home Routing Architecture for VoLTE
    • Robust Call Setup for VoLTE subscriber in LTE
    • Enhancements to Domain Selection between VoLTE and CDMA CS
    • MBMS improvements
    • eMBMS enhancements for LTE
    • IMS related items
    • Evolution to and Interworking with eCall in IMS
    • Password-based service activation for IMS Multimedia Telephony service
    • Multimedia Priority Service Modifications
    • Enhancements to Multi-stream Multiparty Conferencing Media Handling
    • Enhancement for TV service
    • Improved Streaming QoE Reporting in 3GPP (IQoE)
    • Quality of Experience (QoE) Measurement Collection for streaming services in UTRAN
    • Development of super-wideband and fullband P.835
    • Enhancements to User Location Reporting Support
    • Enhancing Location Capabilities for Indoor and Outdoor Emergency Communications
    • Further Indoor Positioning Enhancements for UTRA and LTE
    • Improvements of awareness of user location change
    • Terminating Access Domain Selection (T-ADS) supporting WLAN Access
    • Enhanced LTE-WLAN Aggregation (LWA)
    • Enhanced LTE WLAN Radio Level Integration with IPsec Tunnel (eLWIP)
    • Positioning Enhancements for GERAN
    • New GPRS algorithms for EASE
    • RRC optimization for UMTS
    • Multi-Carrier Enhancements for UMTS
    • DTX/DRX enhancements in CELL_FACH
    • LTE radio improvements
    • Enhancements on Full-Dimension (FD) MIMO for LTE
    • Downlink Multiuser Superposition Transmission for LTE
    • Performance enhancements for high speed scenario in LTE
    • Control and User Plane Separation (CUPS) of EPC nodes
    • Paging Policy Enhancements and Procedure
    • Shared Subscription Data Update
    • Service Domain Centralization
    • Control of Applications when Third party Servers encounter difficulties
    • PS Data Off Services
    • Enhancement to Flexible Mobile Service Steering 
    • Sponsored data connectivity improvements
    • Group based enhancements in the network capability exposure functions
    • Improved operator control using new UE configuration parameters
    • Charging and OAM stand alone improvements
    • Rel-14 Charging
    • ...

    Further Reading:


    Thursday, 9 November 2017

    Quick tutorial on Mobile Network Sharing Options


    Here is a quick tutorial on mobile network sharing approaches, looking at site/mast sharing, MORAN, MOCN and GWCN. Slides with video embedded below. If for some reason you prefer direct link to video, its here.



    See also:

    Sunday, 5 November 2017

    RRC states in 5G

    Looking back at my old post about UMTS & LTE (re)selection/handovers, I wonder how many different kinds of handovers and (re)selection options may be needed now.

    In another earlier post, I talked about the 5G specifications. This can also be seen in the picture above and may be easy to remember. The 25 series for UMTS mapped the same way to 36 series for LTE. Now the same mapping will be applied to 38 series for 5G. RRC specs would thus be 38.331.

    A simple comparison of 5G and LTE RRC states can be seen in the picture above. As can be seen, a new state 'RRC Inactive' has been introduced. The main aim is to maintain the RRC connection while at the same time minimize signalling and power consumption.

    Looking at the RRC specs you can see how 5G RRC states will work with 4G RRC states. There are still for further studies (FFS) items. Hopefully we will get more details soon.

    3GPP TS 22.261, Service requirements for the 5G system; Stage 1 suggests the following with regards to inter-working with 2G & 3G

    5.1.2.2 Legacy service support
    The 5G system shall support all EPS capabilities (e.g., from TSs 22.011, 22.101, 22.278, 22.185, 22.071, 22.115, 22.153, 22.173) with the following exceptions:
    - CS voice service continuity and/or fallback to GERAN or UTRAN,
    - seamless handover between NG-RAN and GERAN,
    - seamless handover between NG-RAN and UTRAN, and
    - access to a 5G core network via GERAN or UTRAN.

    Tuesday, 26 September 2017

    5G Dual Connectivity, Webinar and Architecture Overview

    One of the things that will come as a result of NSA (Non-StandAlone) architecture will be the option for Dual Connectivity (DC). In fact, DC was first introduced in LTE as part of 3GPP Release 12 (see 3G4G Small Cells blog entry here). WWRF (Wireless World Research Forum) has a good whitepaper on this topic here and NTT Docomo also has an excellent article on this here.

    A simple way to understand the difference between Carrier Aggregation (CA) and Dual Connectivity (DC) is that in CA different carriers are served by the same backhaul (same eNB), while in DC they are served by different backhauls (different eNB or eNB & gNB).


    We have produced a short video showing different 5G architectures, looking mainly at StandAlone (SA) and Non-StandAlone (NSA) architectures, both LTE-Assisted and NR-Assisted. The video is embedded below:



    Finally, 3GPP has done a short webinar with the 3GPP RAN Chairman Balazs Bertenyi explaining the outcomes from RAN#77. Its available on BrightTalk here. If you are interested in the slides, they are available here.

    Related posts: