5G New Radio (NR), Architecture options and migration from LTE

You have probably read about the demanding requirements for 5G in many of my blog posts. To meet these demanding requirements a 'next-generation radio' or 'new radio' (NR) will be introduced in time for 5G. We dont know as of yet what air interface, modulation technology, number of antennas, etc. for this NR but this slide above from Qualcomm gives an idea of what technologies will be required for this 5G NR.

The slide above gives a list of design innovations that will be required across diverse services as envisioned by 5G proponents.

It should be mentioned that Rel-10/11/12 version of LTE is referred to as LTE-Advanced and Rel-13/14 is being referred to as LTE-A Pro. Rel-15 will probably have a new name but in various discussions its being referred to as eLTE.

When first phase of 5G arrives in Rel-15, eLTE would be used for access network and EPC will still be used for core network. 5G will use NR and eventually get a new core network, probably in time for phase 2. This is often referred to as next generation core network (NGCN).

The slides below from Deutsche Telekom show their vision of how operators should migrate from eLTE to 5G.

The slides below from AT&T show their vision of LTE to 5G migration.

Eiko Seidel posted the following in 3GPP 5G standards group (i recommend you join if you want to follow technical discussions)


Summary RAN1#86 on New Radio (5G) Gothenburg, Sweden

At this meeting RAN1 delegates presented and discussed numerous evaluation results mainly in the areas of waveforms and channel coding.

Nonetheless RAN1 was not yet prepared to take many technical decisions. Most agreements are still rather general. 

First NR terminology has been defined. For describing time structures mini-slots have been introduced: a mini-slot is the smallest possible scheduling unit and smaller than a slot or a subframe.

Discussions on waveforms favored filtered and windowed OFDM. Channel coding discussions were in favor of LDPC and Turbo codes. But no decisions have been made yet.

Not having taken many decisions at this meeting, RAN1 now is behind its schedule for New Radio.
Hopefully the lag can be made up at two additional NR specific ad hoc meetings that have been scheduled for January and June 2017.

(thanks to my colleague and friend Dr. Frank Kowalewski for writing this short summary!)

Yet another post from Eiko on 3GPP RAN 3 on related topic.

The RAN3 schedule is that in February 2017 recommendations can be made for a protocol architecture.  In the meeting arguments came up by some parties that the work plan is mainly addressing U-Plane architecture and that split of C- and U-plane is not considered sufficiently. The background is that the first step will be dual connectivity with LTE using LTE RRC as control plane and some companies would like to concentrate on this initially. It looks like that a prioritization of features might happen in November timeframe. Beside UP and CP split, also the functional split between the central RAN node and the distributed RAN node is taking place for the cloud RAN fronthaul interface. Besides this, also discussion on the fronthaul interface takes place and it will be interesting to see if RAN3 will take the initiative to standardize a CPRI like interface for 5G. Basically on each of the three interfaces controversial discussion is ongoing.

Yet another basic question is, what is actually considered as a “New 5G RAN”? Is this term limited to a 5G eNB connected to the NG core? Or can it also be also an eLTE eNB with Dual Connectivity to 5G? Must this eLTE eNB be connected to the 5G core or is it already a 5G RAN when connected to the EPC? 

Finally, a slide from Qualcomm on 5G NR standardization & launch.

Updates from the 3GPP RAN 5G Workshop - Part 2

I have finally got round to having a look at some more presentations on 5G from the recently concluded 3GPP RAN 5G Workshop. Part 1 of the series is here.

Panasonic introduced this concept of Sub-RAT's and Cradle-RAT's. I think it should be obvious from the picture above what they mean but you can refer to their presentation here for more details.

Ericsson has provided a very detailed presentation (but I assume a lot of slides are backup slides, only for reference). They have introduced what they call as "NX" (No compatibility constraints). This is in line to what other vendors have referred to as well that above 6GHz, for efficiency, new frame structures and waveforms would serve best. Their slides are here.



Nokia's proposal is that in the phase 1 of 5G, the 5G Access point (or 5G NodeB) would connect to the 4G Evolved Packet Core (EPC). In phase 2, both the LTE and the 5G (e)NodeB's would connect to the 5G core. Their presentation is available here.

Before we move on to the next one, I should mention that I am aware of some research that is underway, mostly by universities where they are exploring an architecture without a centralised core. The core network functionality would be distributed and some of the important data would be cached on the edge. There will be challenges to solve regarding handovers and roaming; also privacy and security issues in the latter case.

I quite like the presentation by GM research about 5G in connected cars. They make a very valid point that "Smartphones and Vehicles are similar but not the same. The presentation is embedded below.

Qualcomm presented a very technical presentation as always, highlighting that they are thinking about various future scenarios. The picture above, about phasing is in a way similar to the Ericsson picture. It also highlights what we saw in part 1, that mmW will arrive after WRC-19, in R16. Full presentation here.

The final presentation we are looking is by Mitsubishi. Their focus is on Massive MIMO which may become a necessity at higher frequencies. As the frequency goes higher, the coverage goes down. To increase the coverage area, beamforming can be used. The more the antennas, the more focused the beam could be. They have also proposed the use of SC-FDMA in DL. Their presentation is here and also embedded below.

MCPTT Off-network and UE to UE/Network Relays

3GPP SA6 recently held a workshop on Mission Critical Push To Talk (MCPTT) stage 3 development in Canada. You can look at the meeting report here and download any presentations from here.

An interesting presentation that caught my attention was one on "MCPTT Off-network Architecture". The presentation is embedded below where it is described technically what is meant by Off-network. From my understanding an off-network from MCPTT point of view is one where the UE does not have network coverage.

In such a situation a UE can connect to another UE that can connect to UE/network (if available) to relay the message. Its similar to another technology that I have talked about, Multihop Cellular Networks and ODMA. Anyway, here is the presentation:

Sometimes the standards can take too long to develop a feature and apps can come and deliver a similar service at a very short notice. One such App that does something similar is called Firechat, which played a big role in many protests worldwide. The video explaining it below is worth watching.


The problem with Apps is that they cannot be used by the emergency services or other governmental organisations, unless a standard feature is available. This is the expectation from this Off-network relays. It would work in combination with D2D/ProSe.


For anyone interested in the latest Public Safety (PS), here is a presentation by SA6 chairman from July

New LTE UE Categories: 11, 12, 13 and 14 in 3GPP Rel-12

While checking 3GPP TS 36.306, I noticed some new LTE categories have been defined. We now have all the way up to category 14. I also noticed that Wikipedia page has up to Category 15, not sure how/where they got it from. 

The LG Space page has some more details for anyone interested in exploring further.

A Qualcomm demo from MWC for LTE Category 11, if interested.



Finally, other related posts:

• LTE Category-0 low power M2M devices 
• New LTE-A UE Category 9 and 10 in Rel-11
• LTE-Advanced (Rel-10) UE Categories
• 1200Mbps DL with LTE-Advanced

LTE-Hetnet (LTE-H) a.k.a. LTE Wi-Fi Link Aggregation (LWA)

We have talked about the unlicensed LTE (LTE-U), re-branded as LTE-LAA many times on this blog and the 3G4G Small Cells blog. In fact some analysts have decided to call the current Rel-12 non-standardised Rel-12 version as LTE-U and the standardised version that would be available as part of Release-13 as LTE-LAA.

There is a lot of unease in the WiFi camp because LTE-LAA may hog the 5GHz spectrum that is available as license-exempt for use of Wi-Fi and other similar (future) technologies. Even though LAA may be more efficient as claimed by some vendors, it would reduce the usage for WiFi users in that particular spectrum.

As a result, some vendors have recently proposed LTE/WiFi Link Aggregation as a new feature in Release-13. Alcatel-Lucent, Ruckus Wireless and Qualcomm have all been promoting this. In fact Qualcomm has a pre-MWC teaser video on Youtube. The demo video is embedded as follows:



The Korean operator KT was also involved in demoing this in MWC along with Samsung and Qualcomm. They have termed this feature as LTE-Hetnet or LTE-H.

The Korean analyst firm Netmanias have more detailed technical info on this topic.

Link aggregation by LTE-H demonstrated at MWC 2015 (Source: Netmanias)

As can be seen the data is split/combined in PDCP layer. While this example above shows the practical implementation using C-RAN with Remote Radio Head (RRH) and BaseBand Unit (BBU) being used, the picture at the top shows LTE Anchor in eNodeB. There would be a need for an ideal backhaul to keep latency in the eNodeB to minimum when combining cellular and WiFi data.

Comparison of link level Carrier Aggregation technologies (Source: Netmanias)

The above table shows comparison between the 3 main techniques for increasing data rates through aggregation; CA, LTE-U/LAA and LTE-H/LWA. While CA has been part of 3GPP Release-10 and is available in more of less all new LTE devices, LTE-U and LTE-H is new and would need modifications in the network as well as in the devices. LTE-H would in the end provide similar benefits to LTE-U but is a safer option from devices and spectrum point of view and would be a more agreeable solution by everyone, including the WiFi community.

A final word; last year we wrote a whitepaper laying out our vision of what 4.5G is. I think we put it simply that in 4.5G, you can use WiFi and LTE at the same time. I think LTE-H fulfills that vision much better than other proposals.

Detailed whitepaper on Carrier Aggregation by 4G Americas

4G Americas has published a detailed whitepaper on Carrier Aggregation (CA). Its a very good detailed document for anyone wishing to study CA.

Two very important features that have come as part of CA enhancements were the multiple timing advance values that came as a part of Release-11 and TDD-FDD joint operation that came part of Release-12

While its good to see that up to 3 carriers CA is now possible as part of Rel-12 and as I mentioned in my last post, we need this to achieve the 'Real' 4G. We have to also remember at the same time that these CA makes the chipsets very complex and may affect the sensitivity of the RF receivers.

Anyway, here is the 4G Americas whitepaper.

LTE Carrier Aggregation Technology Development and Deployment Worldwide from Zahid Ghadialy

You can read more about the 4G Americas whitepaper in their press release here.

Observed Time Difference Of Arrival (OTDOA) Positioning in LTE

Its been a while I wrote anything on Positioning. The network architecture for the positioning entities can be seen from my old blog post here. 

Qualcomm has recently released a whitepaper on the OTDOA (Observed Time Difference Of Arrival) positioning. Its quite a detailed paper with lots of technical insights.

There is also signalling and example of how reference signals are used for OTDOA calculation. Have a look at the whitepaper for detail, embedded below.

Observed Time Difference Of Arrival (OTDOA) Positioning in 3GPP LTE from Zahid Ghadialy

HSPA+ Carrier Aggregation

Came across Qualcomm's HSPA+ Carrier aggregation video (above) and whitepaper. Interesting to see that HSPA/HSPA+ is still growing. As per my earlier post, half of the connections in 2018 would be HSPA/HSPA+.

As can be seen in the picture above, there are quite a few features that may be of interest to the operators. Scalable UMTS is one such feature as I have put in the blog before.

You will notice that upto 4 bands can be aggregated. It would be interesting to see which operators have these bands available and if they would be willing to use HSPA+ CA with upto 4 bands. The presentation by Qualcomm is embedded below and is available to download from here.

Related posts:

• Multipoint HSDPA / HSPA
• HSDPA multiflow data transmission

Quick summary on LTE and UMTS / HSPA Release-12 evolution by 3GPP

A quick summary from 3GPP about the Release-12 progress (Jun. 2014 release planned) from the recent ETSI Future Mobile Summit. Presentation and video embedded below

LTE TDD - universal solution for unpaired spectrum?

TDD deployments are gathering pace. An earlier GSA report I posted here, highlighted the many devices that are TD-LTE ready.

The main thing that is being emphasised is that from the standards point of view, not much additional efforts are required for a TDD device as compared to an FDD device. Of course in practice the physical layer would be different and that could be a challenge in itself.

Qualcomm published a presentation on this topic that is embedded below. Available to download from here.

Our World Without Mobile :-)

Present and Future Technologies for Internet of Things (IoT)

An Interesting presentation from our Future of Wireless Conference (#FWIC2013) in Cambridge earlier this month. A question being asked is what technology will be used for Internet of Things (IoT) or Internet of Everything (IoE) as its also referred to nowadays. These 3 slides below summarises what technologies are see applicable to which scenarios.

Complete slides are embedded below and if you like to see the video, its available here.

Mapping the Future of the Internet of (Every)Thing(s) from Zahid Ghadialy

eMBMS rollouts gathering steam in 2013

Its been a while since I last posted something on eMBMS. Its been even longer that we saw anything official from 3GPP on eMBMS. Recently I have seen some operators again starting to wonder if eMBMS makes business sense, while the vendors and standards are still working hard on the technology.

Not so long back, HEVC/H.265 codec was standardised. This codec helps transmission of the video using half the bandwidth. This means that it would be economical to use this for broadcast technologies. No wonder Nokia, Thompson and NTT Docomo are excited.

Interesting picture from a Qualcomm presentation (embedded in the end) shows how different protocols fit in the eMBMS architecture. My guess would be that the HEVC  may be part of the Codecs.

On the operators front, Korea Telecom (KT) has intentions for countrywide rollout. Korea is one of the very few countries where end users have embraced watching video on small form factors. Verizon wireless has already signalled the intention to rollout eMBMS in 2014; its working out a business case. Telenor Sweden is another player to join the band with the intention of adopting Ericsson's Multi screen technology.

One of the main reasons for the lack of support for the 3G MBMS technology was not a compelling business case. Qualcomm has a whitepaper that outlines some of the potential of LTE Broadcast technology here. A picture from this whitepaper on the business case below:

Finally, a presentation from Qualcomm research on eMBMS embedded below:

LTE eMBMS Technology Overview from Zahid Ghadialy

Scalable UMTS (S-UMTS) to accelerate GSM Refarming

Looks like a good idea from LTE will possibly be applied to UMTS/HSPA and it will also help accelerate the re-farming of GSM spectrum. A recent presentation from Qualcomm below:

Available to download from here.

Videos from the CES 2013

Gorilla glass (above) is made by a company called Corning that is much more well known for its futuristic video, see here.











Finally, this Sony Xperia Z has got over 2 million hits, not exactly sure why so I have added the video for this as well

CSFB Performance

Here is another presentation from Qualcomm from the '4G World'.

CSFB Performance from Zahid Ghadialy

With regards to SI Tunneling mentioned in the presentation, I found the following in another Qualcomm whitepapers:


With Release 9 Enhanced Release with Redirection—SI Tunneling, the device follows 3GPP release 9, where SIB information can be tunneled from the target Radio Access Network (RAN) via the core network to the source RAN and be included in the redirection message sent to the device. This can avoid reading any SIBs on the target cell. 

The predominant solutions deployed today are based on Release 8 Release with Redirection — SIB Skipping, in order to achieve good call setup times, good reliability, and simplify deployments. It is anticipated that Release 9 Enhanced Release with Redirection will be deployed in the near future. At this time, there is not as much push for handover-based CSFB since both Release 8 Release with Redirection—SIB Skipping and Release 9 Enhanced Release with Redirection—SI Tunneling have largely addressed any call setup time issues that may have existed with the Basic Release with Redirection solution.

I have blogged on this topic before, here.

More on Dual Radio here and SVLTE here.

17 LTE Voice Modes

No wonder why LTE chipsets are complicated.

From Qualcomm's presentation in 4G World, available here.

Intelligent Devices and Smart Journeys

Couple of days back, I posted some videos that show technology advancements for the mobile phones. Here is a presentation by Peter Whale from Qualcomm in a recent Cambridge Wireless event about how Sensors and Context-engine will make the future devices much more intelligent then they already are.

Intelligent Devices and Smart Journeys from Zahid Ghadialy

A shameless plug for my presentation on the similar topic from the LTE World Summit 2012, that has now crossed 6000 views, available here.

UK: Spectrum, Operators, Vendors and LTE

So LTE (or '4G') is about to be launched in the UK as announced yesterday. Its going to be branded as 4GEE.

Here is a summary of the Spectrum in the UK that will be used for LTE and would be auctioned by Ofcom.

Here is the current allocation of Spectrum in the UK

The above pics are from a presentation by Ofcom in LTE World Summit 2012 in Barcelona, available here.

The last table is from an Ofcom document here. Its very interesting read. For example I didnt know that The L-band was the first major part of Ofcom spectrum awards programme relevant to mobile services. It consists of 40MHz between 1452MHz and 1492MHz. The auction took place in May 2008, in which Qualcomm won the entirety of the available spectrum.

Here is the summary of the operators working on LTE:


Everything Everywhere (EE = Orange + T-Mobile) - They are calling their '4G' service as EE, covering up to 70% of the UK by the end of 2013. Network kit provided by Huawei.

Three - Samsung will provide the Radio Access Network, and the core infrastructure, for Three's LTE (4G) network. That includes the base stations, and radio core. 3 UK has agreed to purchase 2 x 15 MHz of 1800 MHz spectrum from Everything everywhere, and plans commercial launch of LTE service in 2013.

Telefonica (O2) trial network - Equipment supplied by Nokia Siemens Networks (NSN) for both the Radio and Core network elements. Backhaul for the 4G trial network has been provided using Microwave Radio Equipment from Cambridge Broadband Networks Limited, NEC and Nokia Siemens Networks.

Updated 13/09/12 - 11:25

UK Broadband rolled out the first commercial TD-LTE network in London back in February (available to customers since May 2012). The equipment is provided by Huawei. They have 40MHz in Band 42 (3.5GHz) and 84MHz in band 43 (3.6GHz).

Vodafone - No news.


Anything else I missed?

Qualcomm's 1000x Challenge

Qualcomm has been promoting the '1000x' challenge and has recently held a webinar to make everyone aware of how 1000 times efficiency may be achieved. I think there is always a scope of achieving a better efficiency but putting a figure may not necessarily give the desired results. Anyway, here are the slides.

The 1000x Mobile Data Challenge from Qualcomm Wireless Evolution

You can listen to the webinar here. The promotional video is available here.

A writeup on this topic by Steven Crowley is available here.