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Thursday, 20 April 2017

5G: Architecture, QoS, gNB, Specifications - April 2017 Update


The 5G NR (New Radio) plan was finalised in March (3GPP press release) and as a result Non-StandAlone (NSA) 5G NR will be finalised by March 2018. The final 3GPP Release-15 will nevertheless include NR StandAlone (SA) mode as well.

NSA is based on Option 3 (proposed by DT). If you dont know much about this, then I suggest listening to Andy Sutton's lecture here.


3GPP TR 38.804: Technical Specification Group Radio Access Network; Study on New Radio Access Technology; Radio Interface Protocol Aspects provides the overall architecture as shown above

Compared to LTE the big differences are:

  • Core network control plane split into AMF and SMF nodes (Access and Session Management Functions). A given device is assigned a single AMF to handle mobility and AAA roles but can then have multiple SMF each dedicated to a given network slice
  • Core network user plane handled by single node UPF (User Plane Function) with support for multiple UPF serving the same device and hence we avoid need for a common SGW used in LTE. UPF nodes may be daisy chained to offer local breakout and may have parallel nodes serving the same APN to assist seamless mobility.

Hat tip Alistair Urie.
Notice that like eNodeB (eNB) in case of LTE, the new radio access network is called gNodeB (gNB). Martin Sauter points out in his excellent blog that 'g' stands for next generation.

3GPP TS 23.501: Technical Specification Group Services and System Aspects; System Architecture for the 5G System; Stage 2 provides architecture model and concepts including roaming and non-roaming architecture. I will probably have to revisit as its got so much information. The QoS table is shown above. You will notice the terms QFI (QoS Flow Identity) & 5QI (5G QoS Indicator). I have a feeling that there will be a lot of new additions, especially due to URLLC.

Finally, here are the specifications (hat tip Eiko Seidel for his excellent Linkedin posts - references below):
5G NR will use 38 series (like 25 series for 3G & 36 series for 4G).

RAN3 TR 38.801 v2.0.0 on Study on New Radio Access Technology; Radio Access Architecture and Interfaces

RAN1 TR 38.802 v2.0.0 on Study on New Radio (NR) Access Technology; Physical Layer Aspects

RAN4 TR 38.803 v2.0.0 on Study on New Radio Access Technology: RF and co-existence aspects

RAN2 TR 38.804 v1.0.0 on Study on New Radio Access Technology; Radio Interface Protocol Aspects

38.201 TS Physical layer; General description
38.211 TS Physical channels and modulation
38.212 TS Multiplexing and channel coding
38.213 TS Physical layer procedures
38.214 TS Physical layer measurements
38.21X TS Physical layer services provided to upper layer
38.300 TS Overall description; Stage-2
38.304 TS User Equipment (UE) procedures in idle mode
38.306 TS User Equipment (UE) radio access capabilities
38.321 TS Medium Access Control (MAC) protocol specification
38.322 TS Radio Link Control (RLC) protocol specification
38.323 TS Packet Data Convergence Protocol (PDCP) specification
38.331 TS Radio Resource Control (RRC); Protocol specification
37.3XX TS [TBD for new QoS]
37.3XX TS Multi-Connectivity; Overall description; Stage-2
38.401 TS Architecture description
38.410 TS NG general aspects and principles
38.411 TS NG layer 1
38.412 TS NG signalling transport
38.413 TS NG Application Protocol (NGAP)
38.414 TS NG data transport
38.420 TS Xn general aspects and principles
38.421 TS Xn layer 1
38.422 TS Xn signalling transport
38.423 TS Xn Application Protocol (XnAP)
38.424 TS Xn data transport
38.425 TS Xn interface user plane protocol
38.101 TS User Equipment (UE) radio transmission and reception
38.133 TS Requirements for support of radio resource management
38.104 TS Base Station (BS) radio transmission and reception
38.307 TS Requirements on User Equipments (UEs) supporting a release-independent frequency band
38.113 TS Base Station (BS) and repeater ElectroMagnetic Compatibility (EMC)
38.124 TS Electromagnetic compatibility (EMC) requirements for mobile terminals and ancillary equipment
38.101 TS User Equipment (UE) radio transmission and reception
38.133 TS Requirements for support of radio resource management
38.104 TS Base Station (BS) radio transmission and reception
38.141 TS Base Station (BS) conformance testing

Note that all specifications are not in place yet. Use this link to navigate 3GPP specs: http://www.3gpp.org/ftp/Specs/archive/38_series/

Further reading:



Saturday, 15 April 2017

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


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

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

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

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

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

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


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

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

Let me know what you think.

Related Links:



Saturday, 8 April 2017

The Iconic British Red Phone Boxes

Source: BBC

Brits love their red phone boxes. Even with mobiles prevalent today, we don't want to get rid of the phone boxes. The BBC estimates that there are 46,000 phones boxes in use today, including 8,000 red ones.

Some of these phone boxes are being put to other interesting uses too. One of them has become 'world's smallest museum', another has been converted into a coffee shop, yet another one is a salad bar and another one in Cumbria is hosting life saving medical equipment. This is all thanks to BT that has encouraged adoption of some of these much loved icons for as little as £1.



Two British Phonebox enthusiasts, Prof. Nigel Linge and Prof. Andy Sutton have written a very well researched and comprehensive book on this topic looking at the history and evolution of the humble phone boxes through all of its major models, including those that were introduced by organisations such as the emergency services. The British Phonebox is available to purchase from Amazon and other popular bookshops.


In addition to the book, they have also written an article in 'The Journal' that gives a taster of whats in the book. Its available to download here.

5 interesting facts from the little reading that I did on this topic:

  • The model K1 (K stand for Kiosk) was very unpopular and hence a competition was held to find the best possible design. The winning design by Sir Giles Gilbert Scott became K2 that was rolled out in 1926
  • Sir Giles had suggested silver colour with blue and green interior. This was changed to red for making it easy to spot
  • The latest model is called KX100+
  • The most popular and loved model is the K6 that was designed to celebrate King George V’s Silver Jubilee, though he died before any of them were actually installed.
  • Before Queen Elizabeth came along, a vague representation of the Tudor crown was used on the telephone boxes. Wanting to put her stamp on things after she ascended to the throne in 1952, QEII had all of the crowns changed to St. Edward's Crown, the crown actually used in coronations. Scotland opted to keep the Crown of Scotland on theirs, and so all K6 boxes manufactured after 1955 had to be made with a slot in the top to insert the plate with the correct crown depending on the location of the booth.

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Saturday, 1 April 2017

Some interesting April Fools' Day 2017 Technology Jokes

Here are the interesting April Fools' Day 2017 Technology Jokes. If I have missed one, please add them in comments. For those who don't know what April Fools' Day means, see here.

Google Windmill from Google Nederland: Interesting use of Wind and Cloud to keep Rain away.




Amazon Petlexa (Alexa for Pets): It allows dogs, cats, and other animals to communicate with Alexa just like you do. The Petlexa feature gives pets the freedom to place orders from Amazon, and to activate smart home enabled toys.




Google Play for Pets: A new category of games, apps and training tools to keep your pet stimulated. Honestly, I cant see why this cannot be real.



Honda Horn Emoji's: Horn Emojis offer a range of horn sounds for a variety of scenarios, from seeing your kids off to school to commiserating with other drivers in rush-hour traffic.


See video here. Honda has also launched In-car dating app to help lonely drivers find love at the wheel. More details here.


T-Mobile ONEsie: T-Mobile CEO John Legere has designed this Onesie and CTO Neville Ray has also participated in testing. Its got a lot of Amazing properties, including creating Human SotSpots.


See videos here and here.


Virgin Atlantic Dreambird 1417: World’s first-ever aircraft using new patented technology – flapology – to create the world’s first aircraft with flappable wings.




Virgin Trains (UK) Tickink: Innovative new contactless ticket system, offering customers the opportunity to have their train ticket permanently tattooed on their body, preventing frequent passengers from ever losing their tickets again. Details here.


Virgin Mobile Australia PhoYo:


Prysm Avatar: I quite like this concept. A work drone that enables you to reap the benefits of working from home, without sacrificing the interpersonal advantages of being in the office. Each drone is equipped with sophisticated sensors and a holographic projector that displays your likeness as a realistic, life-sized avatar.




Telenor prohibits the word ‘Digital’ in all communication: There is a small chance this may be true ;-). See here.


Finally, there was also Google Gnome (like Google home), Google Ms. Pac-ManLexus LC: Lane ValetShake Me - by Trade Me, Huawei Mate 9.2 with 2 headphone jacks


There is also this picture from 1992 circulating, showing how standards body (ETSI) celebrated April Fools' before twitter/youtube :-)


Related Posts:

Sunday, 19 March 2017

Latest on 5G Spectrum - March 2017

In an earlier post I mentioned that there will be three different types of spectrum that would be needed for 5G; coverage layer, capacity layer and high throughput layer. There is now a consensus within the industry for this approach.


In a 5G seminar, back in Jan, there were a few speakers who felt that there is an informal agreement about the frequencies that will be used. One such slide from Ofcom could be seen in the picture above. Ofcom has also recently released a report expanding on this further.


Analysys Mason has nicely summarized the bands suggested by Ofcom and possibly available in the UK for 5G in the picture above.

Global mobile Suppliers Association (GSA) has also nicely summarised the bands under investigations and trials as follows:

Coverage Layer600 MHz, 700 MHz, 800 MHz, 900 MHz, 1.5 GHz, 2.1 GHz, 2.3 GHz and 2.6 GHz

Capacity Layer:

Europe                     3400 – 3800 MHz (awarding trial licenses)

China                       3300 – 3600 MHz (ongoing trial), 4400 – 4500 MHz, 4800 – 4990 MHz

Japan                       3600 – 4200 MHz and 4400-4900 MHz

Korea                       3400 – 3700 MHz

USA                          3100 – 3550 MHz (and 3700 – 4200 MHz)

High Throughput Layer:

USA:      27.5 – 28.35 GHz and 37 – 40 GHz pre-commercial deployments in 2018

Korea:   26.5 – 29.5 GHz trials in 2018 and commercial deployments in 2019

Japan:   27.5 – 28.28 GHz trials planned from 2017 and potentially commercial deployments in 2020

China:    Focusing on 24.25 – 27.5 GHz and 37 – 43.5 GHz studies

Sweden: 26.5 – 27.5 GHz awarding trial licenses for use in 2018 and onwards

EU:        24.25 – 27.5 GHz for commercial deployments from 2020

Finally, as a reminder, list of bands originally approved for IMT-2020 (5G) as follows:


Another potential band, not being mentioned above is the 66-76GHz spectrum. This band is adjacent to the 60 GHz Wi-Fi (57 GHz - 66 GHz). Lessons learned from that band can be applied to the 5G band too.

Related links:



Thursday, 16 March 2017

Satellite Industry is Gearing up for The Next Revolution in Communications

Intelsat graphic
Source: Intelsat
I have been talking about the role of satellites in future communications on my blog and various industry fora. While most of the telecom industry is focused on 5G, it’s good to see that the satellite industry is getting ready for the next revolution.

Source: New York Times
Masayoshi Son, chief executive of SoftBank has made it his mission to merge satellite operators Intelsat and OneWeb. While on the surface they may seem as competitors, in reality they complement each other. Intelsat operates geostationary (GEO) satellites while OneWeb is building low earth orbit (LEO) satellites. They both serve overlapping but different purposes and it makes sense for them to work together. LEO satellites which are roughly at 1200km have far lower latency than compared to GEO satellites that are 36,000km away. On the other hand LEO satellites do not appear stationary unlike GEO satellites.

We in CW are already aware of Masayoshi Son’s ambition and vision. Last year Softbank acquired ARM for approximately £24 billion. In a recent keynote delivered at the Mobile World Congress 2017 (#MWC17), Son explained his vision and reasoning for this purchase. In fact he mentioned that he has a 30 year vision which is why he thinks ‘cell towers from space’ are the next step in evolution. While he refers to them as fiber from the space, I wouldn’t go that far in comparison but do admit they have the potential to deliver high speed connectivity anywhere on earth.

The most obvious application of high speed connectivity ubiquitously available anywhere on earth are connected cars. While there is Wi-Fi to provide connectivity and software updates when parked at home, it will be complemented by mobile connectivity within the cities and the major roads. What is missing is anywhere and everywhere connectivity that the satellites can bring.

The big barrier for satellite connectivity in the cars had been the need for satellite dish mounted on the top of a car roof. Kymeta, an innovative company based in Washington, USA has been trying for years to solve this problem. In May, they will start selling  their “lightweight flat-panel antennas, meant to bring fast satellite-transmitted internet connections to cars, trains and boats”.

Source: Seattle Times
Kymeta is partnering with Toyota and Intelsat to bring a complete solution for future connectivity in the cars. They are not the only ones, there are other similar interesting projects ongoing in many different parts of the world.


The telecom industry cannot ignore satellite communications forever. Satellites have already proved themselves beyond doubt in broadcasting, navigation, earth observation, etc. It’s just a matter of time before they prove their while in communications as well.

Originally Posted on CW Blog here.

Sunday, 12 March 2017

High Power / Performance User Equipment (#HPUE)

3GPP refers to HPUE as High Power UE while the US operator Sprint prefers to use the term High Performance UE.

HPUE was initially defined for US Public Safety Band 14 (700MHz). The intention was that this high power UEs can increase the coverage range from 4km to 8km. This would mean larger coverage areas and less number of cells.

While the commercial UE's (class 3) transmit at +23dBm (max 200mW), the Public Safety people intend to use class 1 UE transmitting +31 dBm (max 1.25W). It was felt that this feature could be beneficial for some TDD bands that do not have to worry about backward compatibility. One such band, pushed by Sprint was TDD Band 41 (2500MHz). As this band is for the commercial UE's, instead of class 1, class 2 power at +26dBm (max 400mW) was proposed.

3GPP TS 36.886 provides the following justification:

Currently, 3GPP has defined only Power Class UE 3 as the type of UE supported for TDD LTE band 41 operations. This definition was based on aligning TDD LTE Band 41 UE power classes with prior work in 3GPP related to other bands. However, it should be mentioned that 3GPP UE Power Class 3 definition (i.e. 23dBm) was mainly driven to ensure backward compatibility with prior technologies (i.e. GSM/UMTS) [2] so that network deployment topologies remain similar. Furthermore, maintaining the same power class UE definition (i.e. Class 3) as previous technologies would maintaining compliance with various national regulatory rulings, particularly in terms of SAR, for FDD LTE duplexing mode. 

However, TDD LTE band 41 does not have any 3GPP legacy technologies associated with it, hence the backward compatibility consideration is not applicable in its case. Also, since band 41 is defined as a TDD LTE band, it is less susceptible to SAR levels that FDD LTE bands due to SAR definition. Therefore, defining a new UE power class with higher than 23dBm Tx power for TDD LTE Band 41 operations would not compromise any of 3GPP foundational work, while improving UE and network performance. It should also be mentioned that 3GPP has done similar work on other bands (i.e. band 14) when defining a higher power class UE, hence the concept presented in this document is a continuation of that process.

The present document carries out a feasibility analysis for defining a UE Power class 2 (i.e. 26dBm) for operation on TDD LTE band 41. The document analyses current and future technological advancements in the area of UE RF front-end components and architectures that enable such definition while maintaining 3GPP specification and other regulatory bodies' requirements. It should be emphasized that this proposal only relates to single carrier UL operations on TDD band 41 (i.e. TM-1/2 modes) without affecting current 3GPP definition for UL carrier aggregation on band 41.

As you can see from the tweet above, Sprint CEO is quite pleased with the HPUE. 

SourceDiana Goovaerts

Iain Gillott, iGR points out that HPUE applies to Sprint’s 2.5 GHz TDD network and associated spectrum, and the company claims up to 30 percent increase in cell cover from the new technology.  It should be noted that HPUE is a 3GPP standard that applies to the 2.5 GHz TDD band (Band 41) and is also to be used by China Mobile and Softbank.  HPUE was developed as part of the Global TDD LTE Initiative (GTI) which includes Qualcomm Technologies, Samsung, ZTE, Broadcom, MediaTek, Skyworks Solutions, Alcatel, Motorola, LG and Qorvo... The cool part: the improvement in coverage comes from simply improving the device uplink power.  So Sprint, China Mobile and Softbank will not have to visit their cell sites to make changes; they just need 2.5 GHz TDD devices with HPUE to get the benefit.


Milan Milanović recently wrote about Sprint’s Gigabit Class LTE network goes live in New Orleans. One of the questions I had was why is the uplink so rubbish as compared to downlink. He kindly pointed out to me that this is TDD config 2
If you are wondering what is TDD Config 2, see the pic below
Source: ShareTechNote

Sprint expects HPUE to appear in postpaid devices starting in 2017, including new devices from Samsung, LG, HTC, and Moto. It’s expected that all of Sprint’s new devices will have HPUE support within the next two years.

I think it would be interesting to see how this impacts when there are a lot more users and devices. I am quite sure there will be more requests for HPUE in further TDD bands.

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