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 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.

Sunday, 29 October 2017

5G Forecasts and 5G Deployed Claim

Source: GSA

5G forecasts have been arriving steadily with many different figures. Here are some numbers:

Date Predicted by Number of Connections Year Any other comments
23-Aug-16 Strategy Analytics 690 million 2025 "690M Connections and 300M Handset Shipments"
15-Nov-16 Ericsson 500 million 2022 "North America will lead the way in uptake of 5G subscriptions, where a quarter of all mobile subscriptions are forecast to be for 5G in 2022."
30-Nov-16 ABI Research 500 million 2026 "500 Million 5G cmWave and mmWave Subscribers Will Bring $200 Billion in Service Revenue through 2026" - what about non mmWave/cmWave 5G subs?
12-Apr-17 CCS Insight 100 million 2021 "Smartphones sales will rise to 1.90 billion in 2021, when smartphones will account for 92 percent of the total mobile phone market."
26-Apr-17 GSMA 1.1 billion 2025 "5G connections are set to reach 1.1 billion by 2025, accounting for approximately one in eight mobile connections worldwide by this time."
16-May-17 Ovum 389 million 2022 "Ovum now forecasts that there will be 111 million 5G mobile broadband subscriptions at end-2021, up more than fourfold from Ovum’s previous forecast of 25 million 5G subscriptions at end-2021"
14-Aug-17 Juniper Research 1.4 billion 2025 "an increase from just 1 million in 2019, the anticipated first year of commercial launch. This will represent an average annual growth of 232%."
17-Oct-17 GSMA 214 million in Europe 2025 "30 per cent of Europe’s mobile connections will be running on 5G networks by 2025"
23-Oct-17 CCS Insight 2.6 billion 2025 "1 Billion Users of 5G by 2023, with More Than Half in China", "broadly similar path to 4G LTE technology...more than one in every five mobile connections."

If we just look at 2025/2026, the estimates vary from 500 million to 2.6 billion. I guess we will have to wait and see which of these figures comes true.

I wrote a post earlier titled '4G / LTE by stealth'. Here I talked about the operators who still had 3G networks while most people had 4G phones. The day the operator switched on the 4G network, suddenly all these users were considered to be on 4G, even if they didn't have 4G coverage just yet.

I have a few questions about what 5G features are necessary for the initial rollout and when can an operator claim they have 5G? In fact I asked this question on twitter and I got some interesting answers.

Just having a few 5G NR (new radio) sites enough for an operator to claim that they have deployed 5G? Would all the handsets with 5G compatibility then be considered to be on 5G? What features would be required in the initial rollouts? In case of LTE, operators initially only had Carrier Aggregation deployed, which was enough to claim they supported LTE-A. Would 100MHz bandwidth support be enough as initial 5G feature?

Please let me know what you think.

Monday, 23 October 2017

5G Architecture Options for Deployments?

I have blogged earlier about the multiple 5G Architecture options that are available (see Deutsche Telekom's presentation & 3G4G video). So I have been wondering what options will be deployed in real networks and when.
The 3GPP webinar highlighted that Option-3 would be the initial focus, followed by Option 2.

Last year AT&T had proposed the following 4 approaches as in the picture above. Recall that Option 1 is the current LTE radio connected to EPC.

ZTE favours Deployment option 2 as can be seen in the slide above

Huawei is favoring Option 3, followed by Option 7 or 2 (& 5)

Going back to the original KDDI presentation, they prefer Option 3, followed by Option 7.

If you are an operator, vendor, analyst, researcher, or anyone with an opinion, what options do you prefer?

Saturday, 21 October 2017

Evolution of SON in 3GPP

A good list of 3GPP Evolution of SON features. Whitepaper available here. You may also like the earlier post here.

See also: Self-Organizing Networks / Self-Optimizing Networks (SON) - 3G4G Homepage

Thursday, 12 October 2017

3GPP Sidelink and its proposed extensions

In an earlier post I discussed briefly about the sidelink: V2V communications are based on D2D communications defined as part of ProSe services in Release 12 and Release 13 of the specification. As part of ProSe services, a new D2D interface (designated as PC5, also known as sidelink at the physical layer) was introduced and now as part of the V2V WI it has been enhanced for vehicular use cases, specifically addressing high speed (up to 250Kph) and high density (thousands of nodes).

Before going further, lets just quickly recap the different V2x abbreviations:

  • V2X = Vehicle-to-Everything
  • V2V = Vehicle-to-Vehicle
  • V2I = Vehicle-to-Infrastructure 
  • V2P = Vehicle-to-Pedestrian 
  • V2H = Vehicle-to-Home
  • eV2X = enhanced Vehicle-to-Everything

I came across this interesting presentation from ITRI that provides lot more details on sidelink and its proposed extension to other topics including eV2X and FeD2D (Further enhanced Device-to-Device).

There are quite a few references in the document that provides more details on sidelink and its operation and extension to other devices like wearables.

There are also details on synchronization and eV2X services.

There is also a very nice D2D overview presentation by Orange that I am embedding below (download from slideshare)

Saturday, 7 October 2017

2G / 3G Switch Off: A Tale of Two Worlds

Source: Wikipedia

2G/3G switch off is always a topic of discussion in most conferences. While many companies are putting their eggs in 4G & 5G baskets, 2G & 3G is not going away anytime soon.

Based on my observations and many discussions that I have had over the past few months, I see a pattern emerging.

In most developed nations, 2G will be switched off (or some operators may leave a very thin layer) followed by re-farming of 3G. Operators will switch off 3G at earliest possible opportunity as most users would have moved to 4G. Users that would not have moved to 4G would be forced to move operators or upgrade their devices. This scenario is still probably 6 - 10 years out.

As we all know that 5G will need capacity (and coverage) layer in sub-6GHz, the 3G frequencies will either be re-farmed to 4G or 5G as 2G is already being re-farmed to 4G. Some operators may choose to re-balance the usage with some lower frequencies exchanged to be used for 5G (subject to enough bandwidth being available).

On the other hand, in the developing and less-developed nations, 3G will generally be switched off before 2G. The main reason being that there are still a lot of feature phone users that rely on 2G technologies. Most, if not all, 3G phones support 2G so the existing 3G users will be forced onto 2G. Those who can afford, will upgrade to newer smartphones while those who cant will have to grudgingly use 2G or change operators (not all operators in a country will do this at the same time).

Many operators in the developing countries believe that GSM will be around until 2030. While it may be difficult to predict that far in advance, I am inclined to believe this.

For anyone interested, here is a document listing 2G/3G switch off dates that have been publicly announced by the operators.

Let me know what you think.

Further reading:

Friday, 29 September 2017

Smartphone Wi-Fi Analytics for Travel Route Optimisations

Transport for London (TFL), the local government body responsible for transport in London, which also runs the London Underground (known as Tubes) has been using smartphone Wi-Fi data to work out how people travel on the stations.

They did the trial and collected data in 2016 and have also openly talked about it (see this talk for example), they have now published their findings which is available here. One of the interesting findings for example is that 18 different routes taken by customers between King's Cross St Pancras and Waterloo - and many people don't use the shortest route changing Tube lines

Its interesting to think that because many people do not have their Wi-Fi switched on while outside and many others who put their phone in plane more while in the underground (no mobile coverage, in case you are wondering), this data is probably not as detailed as it could have been.

Nevertheless, there is a talk of bringing Mobile connectivity into the underground network. Once its there, the combination of data could be far more valuable.

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:

Wednesday, 20 September 2017

A quick starter on 4G voice (for beginners)

I recently did a 4G voice presentation for beginners after realizing that even though so many years have passed after VoLTE was launched, people are still unsure how it works or how its different from CS Fallback.

There are many other posts that discuss these topics in detail on this blog (follow the label) or on 3G4G website. Anyway, here is the video:

The slides are available on 3G4G Slideshare account here. More similar training videos are available here.