Tuesday, 22 October 2019

From traditional RAN to Open RAN - O-RAN: Goals and Challenges


My Open RAN tutorial has recently gained popularity with recent announcements from Altiostar, Mavenir, Parallel Wireless, Telefonica and Vodafone. With TIP Summit in few weeks time, I am hoping for a lot more curious people to discover that blog post and video.

Olivier Simon, Director, Radio Innovation, Orange spoke about "O-RAN: Goals and Challenges" at Open Networking Summit Europe 2019. In his presentation, he explained how O-RAN will trigger more intelligence and openness in the RAN domain. He talked about which use cases will require this new architecture and why O-RAN is coming at the right time. Major architectural change are necessary in the next years in order to improve E2E latency and benefit from the flexibility of virtualized network functions. O-RAN will provide the right framework in order to perform this transformation in an open manner and keeping at the same time economies of scale thanks to a global adoption.


The presentation also touches on O-RAN Software Community. The O-RAN Alliance recently partnered with the Linux Foundation to establish the O-RAN-Software Community (O-RAN-SC), to provide that open source software application layer to the RAN. O-RAN-SC will foster development of an open source infrastructure platform for running 5G RAN solutions.

The key aspects of ORAN-SC are:
  • New Open Community focused on RAN Software in collaboration with O-RAN Alliance
  • Set up for collaboration across OPNFV, ONAP, Akraino and other Open Source projects

Here is the video of the conference embedded below:



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Tuesday, 15 October 2019

Summary of #CWTEC 2019 Conference: 5G, Satellites & Magic MIMO

I was involved in helping organise yet another CW TEC conference this year. The topic was quite interesting and we had some brilliant speakers. Some of the excellent presentations were shared too, links below. Here is a very quick summary of the event, linking also to couple of excellent summaries below.

The topic was a bit unusual and it rhymed very well with the attendees which were from many different backgrounds, from 5G, communications, satellites, electronics, T&M companies, etc. Here is the opening video that will show you the motivations behind this



The day started with a breakfast briefing from Cambridge Consultants that looked at how Massive MIMO is the key to unlocking 5G User Experiences. Presentations available here.


Session 1 was titled "What has Massive MIMO ever done for us?". The narrative for the session was as follows:
Clearly the desire for more and more capacity in cellular networks has driven the industry to find more and more novel techniques. The work done over the years and boosted by Tom Marzetta’s article titled “Noncooperative Cellular Wireless with Unlimited Numbers of Base Station Antennas” has set high expectations for this emergent technology, so much so the term Magic MIMO has been coined. However, how significant is it into today’s early 5G rollout and what can we expect over the coming years? Are there still further enhancements we should expect to see?

There were 3 talks as follows:
  • Sync Architectures for 5G NR by Chris Farrow, Technical Manager, Chronos Technology (slides)
  • Three UK’s RAN transformation: Spectrum, RAN architecture strategy, Why? by Dr Erol Hepsaydir, Head of RAN and Devices Strategy and Architecture, Three UK (slides)
  • Active antenna systems in RAN: performance, challenges and evolution by Anvar Tukmanov, Wireless Research Manager, BT


Session 2 looked at "Non-Terrestrial & Hybrid Networks". The narrative for the session was as follows:
There are different initiatives underway to make satellite and other non-terrestrial networks as part of 5G. In addition, many different mobile operators have demonstrated compelling use-cases with drones, balloons and other aerostats. Other innovative approaches like European Aviation Network uses a hybrid-network using terrestrial network supported by a satellite connection as a backhaul for in-flight Wi-Fi. In addition to latency, what other challenges are stopping mass adoption of Non-terrestrial and Hybrid networks? What about advanced features like slicing, etc.?

There were 3 talks as follows:

  • Opportunities for blending terrestrial and satellite technologies by Dr Jaime Reed, Director, Consulting, Space, Defence and Intelligence, CGI (slides)
  • Non-terrestrial Networks: Standardization in 5G NR by Dr Yinan Qi, Senior 5G Researcher, Samsung R&D Institute UK
  • Satellites and 5G: A satellite operator’s perspective by Simon Watts, Principal Consultant, Avanti Communications


Session 3 looked at "5G: A Catalyst for Network Transformation". The narrative was as follows:
5G has set high expectations in the user as well as operator community. While eMBB can be supported with an upgrade of existing 4G infrastructure, URLLC and mMTC may require massive change in the network architecture. Operators have already started the transformation process with backhaul upgrades, new data centers, distributed core and cloud rollouts, etc. How are networks evolving to accommodate these deep changes? What other changes will be required in the network to support the growth until the next new generation arrives?
This session featured 3 talks as well
  • An Introduction to Open RAN Concept by Zahid Ghadialy, Senior Director, Strategic Marketing, Parallel Wireless UK & EMEA (slides)
  • Powering the successful deployment of 5G infrastructure by David George, Vice President of EMEA and APAC, Sitetracker (slides)
  • The 5G transformation: no sweet without sweat by Antonella Faniuolo, Head of Network Strategy, Planning, Digital & Optimisation, Vodafone (slides)


The final session topic was "Getting ready for Beyond-5G Era". The narrative was as follows:
Many technologies like Full duplex, etc. that were originally intended to be part of 5G were not able to make it into the standards. Along with these, what other revolutionary changes are needed to make Beyond-5G technologies not only fulfil the vision, ambition and use-cases that were originally envisaged for 5G but to take it a step further and make it a game changer.
This session featured 3 talks as well, as follows:
  • Thinking Beyond 5G: Projects and Initiatives by Alan Carlton, Vice President, InterDigital Europe
  • 5G Evolution: Progressive enhancement and new features for new markets by Matthew Baker, Head of Radio Physical Layer and Coexistence Standardization, Nokia (slides)
  • Why 6G’s design goals need far more than just radio & core innovation by Dean Bubley, Analyst & Futurist, Disruptive Analysis
And my personal highlight was that I launched World's first coloured 5G tie


Hopefully you found the presentations shared as useful. Please also read the summaries of CWTEC provided below.


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Monday, 7 October 2019

Exploiting Possible 5G Vulnerabilities


The standards can try their best to ensure that the next generation of protocols is more secure than the previous one but there is always some way in which the protocols can be exploited. This is where researchers play an important role in finding such vulnerabilities before they can be exploited by hackers. Frankly I am quite sure that only a handful of these vulnerabilities are found and hackers always have something that may never be found.

In the recent HITBSecConf or the Hack In The Box Security Conference Altaf Shaik presented "4G to 5G: New Attacks". He along with Ravishankar Borgaonkar has been working to find out issues with security in cellular networks. In fact in the GSMA Mobile Security Hall of Fame, they both appear twice, individually.

From the talk narrative:

5G raises the security bar a level above 4G. Although IMSI exposure is prevented in 5G, we found new vulnerabilities to attack devices and subscribers. In this talk we expose a set of vulnerabilities in the 5G/4G protocols that are found in network operators equipment and also consumer devices such as phones, routers, latest IoT sensors, and even car modems. Our vulnerabilities affect several commercial applications and use cases that are active in 4G networks and are expected to take off in 5G networks. We developed automated tools to exploit the exposed cellular information and share some of our research traces and data sets to the community. We demonstrate a new class of hijacking, bidding down and battery draining attacks using low cost hardware and software tools. We did a rigorous testing worldwide to estimate the number of affected base stations and are surprised by the results. Finally our interactions with various vendors and standard bodies and easy fixes to prevent our attacks are discussed.

Slides and Video is embedded below






Slides and Whitepaper can be downloaded from here.

Further Reading:

Friday, 4 October 2019

CW Seminar: The present, the future & challenges of AR/VR (#CWFDT)


One of my roles is as a SIG champion of the CW (Cambridge Wireless) Future Devices & Technologies Group. We recently organised an event on "The present, the future & challenges of AR/VR". The CW team has kindly even summarised it here. I have also tried to collect all the tweets from the day here.

Why is this important? Most of the posts on this blog is about the mobile technology and I am guessing most of the readers are from that industry too. While we are focussed too much on connectivity, it's the experience that makes the difference for most of the consumers. On the operator watch blog, I wrote recently about South Korea and the operator LG Uplus. Average data usage by 5G users in Korea is as high as 18.3GB, and average 4G users use 9GB in the same period, according to MSIT in May 2019. 5G data is about 2 times than that of 4G. This remarkable traffic growth is driven by UHD and AR/VR contents. According to the operator LG Uplus, new services featuring AR and VR functions are proving popular and already account for 20% of 5G traffic, compared with 5% for 4G.

Coming back to the CW event, some of the presentations were shared and they are available here for a limited time. There were so many learnings for me, it's difficult to remember and add all of them here.

Our newest SIG champ Nadia Aziz covered many different topics (presentation here) including how to quickly start making your own AR/VR apps and how AR apps will be used more and more for social media marketing in future.


Mariano Cigliano, Creative Developer at Unit9 (presentation here) discussed the journey of their company and what they have learned along the way whilst developing their solution to disrupt the design process through integrating immersive technologies.


Aki Jarvinen from Digital Catapult (presentation here) explained about Brown-boxing and Bodystorming. Both very simple techniques but can help get the app designers story straight and save a lot of time, effort and money while creating the app.


James Watson from Immerse (presentation here) talked about VR training. So many possibilities if done correctly and can be more interactive than the online or classroom training's.



Schuyler Simpson, Vice President - Strategic Partnerships & Operations at Playfusion (presentation here) discussed the reality of enhanced reality, diving deep into the challenges about creating an experience that resonates best with audiences. In his own words, "Enhanced Reality blends visual, audio, haptic, and intelligent components to create highly personalized, immersive, and most importantly, valuable experiences for organizations and their audiences."

The most valuable learning of the day was to create an AR/VR app (just in theory), assuming there is no technology limitation. The whole journey consisted of:

  • Brainstorming of the Use Case
  • Key Pain Points
  • Sort the pain points in priority and select top 3 or 5
  • Map customer journey
  • Define persona for which the app is being designed
  • Map their journey
  • Touch points
  • What can be improved on those touch points 
  • Design a VR/AR application for the defined problem 
  • Storyboarding AR/VR use case
  • UX design considerations – spatial, emotional.. 
  • Scribe a prototype 
  • Playback to others.


Thanks to everyone who helped make this whole event possible, from the SIG champs to the CW team and the host & sponsors NTT Data. Special thanks to our newest SIG champ, Nadia Aziz for tirelessly working to make this event a success.

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Tuesday, 24 September 2019

When does your 5G NSA Device Show 5G Icon?


After I wrote about the 5G Icon Display back in February, I received lots of other useful and related materials, mostly from 3GPP standards delegates. Based on this updated information, I created a presentation and video called 'The 5G Icon Story'. Only recently did I realize that I didn't add it to the blog. So here it is.

And for people who are impatient and directly want to jump to the main point, it's UpperLayerIndication in SIB 2 as can be seen above.

The slides and video is embedded below.





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Sunday, 15 September 2019

5G and Fixed-Mobile Convergence (FMC)


We recently made a new video looking at how 5G architecture caters for Trusted and Untrusted Wireless Access as well as Wireline Access. The presentation discusses:
  • Untrusted non-3GPP access networks;
  • Trusted non-3GPP access networks (TNAN);
  • Wireline access networks;
  • Non-5G-Capable over WLAN (N5CW);
  • Access Traffic Steering, Switching and Splitting (ATSSS)

Slides and video embedded below.





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Thursday, 12 September 2019

How the Addition of 5G Radio Resources Increases the Complexity of LTE Signaling Procedures


While everybody is excited about the growing number of 5G deployments and speed test results it is easy to forget that a highly reliable LTE core and radio access network is the prerequisite for 5G non-standalone (NSA) data transmission.

Indeed, the 5G radio resources are just added to the ongoing LTE connection to provide higher bandwidth that enables in turn higher throughput. In other words: the current 5G deployments are designed for and limited to the needs of enhanced Mobile Broadband (eMBB) traffic.

To boost the user experience a 4G and a 5G base station cooperate and bundle there joint resources in one radio connection. The whole scenario is known as E-UTRA-NR Dual Connectivity (EN-DC) and as a matter of fact this dual connectivity increases the complexity of the RAN signaling tremendously.

The figure below shows the two base stations involved in the radio connection. On the left side is the Master eNodeB (MeNB) that controls the entire signaling connection. On the right side sits the en-gNB, also called Secondary gNodeB (SgNB). The inconsistency of acronyms originates from 3GPP specs. 3GPP 37.340 "E-UTRA and NR Multi-connectivity" can be seen as an umbrella document that originally coined "MeNB" and "SgNB". However, when standarizing more details these acronyms have been replaced with Master Node (MN) and Secondary Node (SN) and the latter is named "en-gNB" when used in EN-DC scenarios. (Sure this spec has a lot more terms to offer an is a must-read for every acroynm enthusiast.)

However, these naming conventions defined in 3GPP 37.340 have not made it into the protocol specs, especially not into 3GPP 36.423 "X2 Application Part" that names its message set for enabling EN-DC consequently "SgNB ...." - as also shown in the figure.

By the way the SgNB should also not be imagined as a single network element. On the 5G side often a virtual RAN architecture is already deployed. In such a VRAN a gNB central unit (CU) controls several gNB distributed units (DUs) and multiple remote radio heads (RRHs) including the 5G antennas can be connected to each DU.



5G Radio Resource Addition in EN-DC Mode

Before 5G radio resources can be added to the connection a LTE RRC connection and at least a default bearer for the user plane including its GTP/IP-Tunnel between S-GW and eNB must have been successfully established.

The trigger for adding 5G resources to this call is mostly an inter-RAT measurement event B1 (not shown in the figure). However, also blind addition of a 5G cells have been observed in some cases where the 5G cell coverage is expected to overlap exactly the footprint of the LTE master cell. 

All in all, there can be a 1:1 mappig between 4G and 5G cells when antennas are mounted very close to each other and pointing into the same direction. However, it is also possible that several 5G small cells (especially when using FR2 frequency bands) are deployed to cover the footprint of a 4G macro cell. 

The end-to-end signaling that adds 5G resources to the connection starts with the X2AP SgNB Addition Request message (1). It contains information about the active E-RABs of the connection, UE NR capabilities and often the singal strenght of the 5G cell as measured before is included as well. The message triggers allocation of 5G radio resources in the SgNB.

Similar to a X2 handover procedure the X2AP SgNB Addition Request Acknowledge message (2) is used to transport a NR RRC CG-Config message (3) back to the MeNB where it is "translated" into NR RRC Connection Reconfiguration and NR RRC Radio Bearer Config messages that are sent to the UE enclosed in a LTE RRC Connection Reconfiguration message. In these messages beside the Cell Group ID the 5G PCI and the absolute SSB frequency (a synonym for NR ARFCN) are found. Both, 5G PCI and SSB frequency in combination represent the identity of a 5G cell "visible" for the UE on the physical 5G radio interface. 

To keep the figure more simple I have spared the "translation" process in MeNB and show instead as next step the combined LTE/NR RRC Connection Reconfiguration Complete (4) that is send by the UE back to the MeNB to confim activation of the 5G radio link. 

After this the UE and the SgNB are ready to the 5G resources for radio transmission. However, one important component is still missing: a new GTP/IP-Tunnel for transporting the payload from the core network's serving gateway (S-GW) to the SgNB. 

The gNB downlink transport layer address (gNB DL TLA) and its appropriate GTP Tunnel Endpoint Identifier (TEID) have been already to the MeNB in step (2). Indeed, there are some more TLAs and TEIDs found in this X2AP message, especially for data forwarding across the X2 user plane interface (not shown in figure).

The MeNB forwards the gNB DL TLA/TEID to the MME (6) where it is forwarded to the S-GW using GTP-C signaling in case the two core network elements are connected over S11 reference point. The uplink TLA/TEID on the S-GW side remain the same as assigned before during establishement of the E-RAB (not shown in figure). So the new tunnel is now ready to be used (7) and transmission of payload packet starts immediately. 

In step (8) the MME confirms the successful tunnel establishment to the MeNB.

To total duration of the entire procedure from step (1) to (8) sums up to slightly more than 100 ms under lab conditions and typically around 300 ms in the live network. 

This delay does not have a direct impact on user plane latency in the initial 5G setup phase. However, the subscriber experience might be different when it comes to inter-MeNB handover, because there is no direct handover between 5G neighbor cells. 

Changing the MeNB due to subscriber mobility means: release all 5G resources on the source (M)eNB side, perform intra-LTE handover to the target (M)eNB and add new 5G resources after handover is successfully completed. 

Thursday, 5 September 2019

Opinion: What is "Real 5G" or "True 5G"


I made another opinion piece couple of weeks back. While it was shared already as part of some channels, here is it on the blog with serves as a permanent link. Video and slides below.





As always, I welcome your opinions, comments & suggestions below.


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Thursday, 29 August 2019

LTE / 5G Broadcast Evolution


It's been a while since I last wrote about eMBMS. A report by GSA last month identified:
- 41 operators known to have been investing in eMBMS
- 5 operators have now deployed eMBMS or launched some sort of commercial service using eMBMS
- GSA identified 69 chipsets supporting eMBMS, and at least 59 devices that support eMBMS


BBC R&D are testing the use of 4G/5G broadcast technology to deliver live radio services to members of the public as part of 5G RuralFirst - one of 6 projects funded under the UK Government’s 5G Phase 1 testbeds and trials programme (link).

A press release by Samsung Electronics back in May announced that it has signed an expansion contract with KT Corporation (KT) to provide public safety (PS-LTE) network solutions based on 3GPP standard Release 13 for 10 major metropolitan regions in South Korea including Seoul by 2020. One of the features of PS-LTE that the PR listed was LTE Broadcast (eMBMS): A feature which allows real time feeds to hundreds of devices simultaneously. It enables thousands of devices to be connected at once to transfer video, images and voice simultaneously using multicast technology

Dr. Belkacem Mouhouche – Samsung Electronics Chief Standards Engineer  and Technical Manager of 5G projects: 5G-Xcast and 5G-Tours Presented an excellent overview on this topic at IEEE 5G Summit Istanbul, June 2019. His presentation is embedded below.



5G-Xcast is a 5GPPP Phase II project focused on Broadcast and Multicast Communication Enablers For the Fifth Generation of Wireless Systems.

They have a YouTube channel here and this video below is an introduction to project and the problems it looks to address.




Further Reading:

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