New LTE UE Categories (Downlink & Uplink) in Release-13

Just noticed that the LTE UE Categories have been updated since I last posted here. Since Release-12 onwards, we now have a possibility of separate Downlink (ue-CategoryDL) and Uplink (ue-CategoryUL) categories.

From the latest RRC specifications, we can see that now there are two new fields that can be present ue-CategoryDL and ue-CategoryUL.

An example defined here is as follows:

Example of RRC signalling for the highest combination
UE-EUTRA-Capability
   ue-Category = 4
      ue-Category-v1020 = 7
         ue-Category-v1170 = 10
            ue-Category-v11a0 = 12
               ue-CategoryDL-r12 = 12
               ue-CategoryUL-r12 = 13
                  ue-CategoryDL-v1260 = 16

From the RRC Specs:

• The field ue-CategoryDL is set to values m1, 0, 6, 7, 9 to 19 in this version of the specification.
• The field ue-CategoryUL is set to values m1, 0, 3, 5, 7, 8, 13 or 14 in this version of the specification.

3GPP TS 36.306 section 4 provides much more details on these UE categories and their values. I am adding these pictures from the LG space website.

More info:

• 3GPP TS 36.331: Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification
• 3GPP TS 36.306: Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio access capabilities
• http://niviuk.free.fr/ue_category.php - up to date info on LTE UE categories
• http://www.sharetechnote.com/html/LTE_Advanced_UE_Category.html

LTE, 5G and V2X

3GPP has recently completed the Initial Cellular V2X standard. The following from the news item:

The initial Cellular Vehicle-to-Everything (V2X) standard, for inclusion in the Release 14, was completed last week - during the 3GPP RAN meeting in New Orleans. It focuses on Vehicle-to-Vehicle (V2V) communications, with further enhancements to support additional V2X operational scenarios to follow, in Release 14, targeting completion during March 2017.

The 3GPP Work Item Description can be found in RP-161894.

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).

...

For distributed scheduling (a.k.a. Mode 4) a sensing with semi-persistent transmission based mechanism was introduced. V2V traffic from a device is mostly periodic in nature. This was utilized to sense congestion on a resource and estimate future congestion on that resource. Based on estimation resources were booked. This technique optimizes the use of the channel by enhancing resource separation between transmitters that are using overlapping resources.

The design is scalable for different bandwidths including 10 MHz bandwidth.

Based on these fundamental link and system level changes there are two high level deployment configurations currently defined, and illustrated in Figure 3.

Both configurations use a dedicated carrier for V2V communications, meaning the target band is only used for PC5 based V2V communications. Also in both cases GNSS is used for time synchronization.

In “Configuration 1” scheduling and interference management of V2V traffic is supported based on distributed algorithms (Mode 4) implemented between the vehicles. As mentioned earlier the distributed algorithm is based on sensing with semi-persistent transmission. Additionally, a new mechanism where resource allocation is dependent on geographical information is introduced. Such a mechanism counters near far effect arising due to in-band emissions.

In “Configuration 2” scheduling and interference management of V2V traffic is assisted by eNBs (a.k.a. Mode 3) via control signaling over the Uu interface. The eNodeB will assign the resources being used for V2V signaling in a dynamic manner.

5G Americas has also published a whitepaper on V2X Cellular Solutions. From the press release:

Vehicle-to-Everything (V2X) communications and solutions enable the exchange of information between vehicles and much more - people (V2P), such as bicyclists and pedestrians for alerts, vehicles (V2V) for collision avoidance, infrastructure (V2I) such as roadside devices for timing and prioritization, and the network (V2N) for real time traffic routing and other cloud travel services. The goal of V2X is to improve road safety, increase the efficiency of traffic, reduce environmental impacts and provide additional traveler information services. 5G Americas, the industry trade association and voice of 5G and LTE for the Americas, today announced the publication of a technical whitepaper titled V2X Cellular Solutions that details new connected car opportunities for the cellular and automotive industries.

The whitepaper describes the benefits that Cellular V2X (C-V2X) can provide to support the U.S. Department of Transportation objectives of improving safety and reducing vehicular crashes. Cellular V2X can also be instrumental in transforming the transportation experience by enhancing traveler and traffic information for societal goals.

C-V2X is part of the 3GPP specifications in Release 14. 3GPP announced the completion of the initial C-V2X standard in September 2016. There is a robust evolutionary roadmap for C-V2X towards 5G with a strong ecosystem in place. C-V2X will be a key technology enabler for the safer, more autonomous vehicle of the future.

The whitepaper is embedded below:

Related posts:

• Feasibility Study on New Services and Markets Technology Enablers for 5G
• Connected and Autonomous vehicles: Beyond Infotainment and Telematics
• Connected and Autonomous Car Revolution

Further Reading:

• Personal View: LTE V2X Specifications approved by 3GPP RAN plenary – Eiko Seidel

QoS in VoWiFi

Came across this presentation by Eir from last year's LTE Voice Summit.

VoWLAN: Call Quality from 3G4G

As the summary of the above presentation says:

• Turning on WMM (or WME) at access point provides significant protection for voice traffic against competing wireless data traffic
• Turning on WMM at the client makes only a small difference where there are a small number of clients on the wireless LAN. This plus the “TCP Unfairness” problem means that it can be omitted.
• All Home gateways support WMM but their firmware may need to be altered to prioritise on DSCP rather than layer two

As this Wikipedia entry explains:

Wireless Multimedia Extensions (WME), also known as Wi-Fi Multimedia (WMM), is a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic Quality of service (QoS) features to IEEE 802.11 networks. WMM prioritizes traffic according to four Access Categories (AC): voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). However, it does not provide guaranteed throughput. It is suitable for well-defined applications that require QoS, such as Voice over IP (VoIP) on Wi-Fi phones (VoWLAN).

WMM replaces the Wi-Fi DCF distributed coordination function for CSMA/CA wireless frame transmission with Enhanced Distributed Coordination Function (EDCF). EDCF, according to version 1.1 of the WMM specifications by the Wi-Fi Alliance, defines Access Categories labels AC_VO, AC_VI, AC_BE, and AC_BK for the Enhanced Distributed Channel Access (EDCA) parameters that are used by a WMM-enabled station to control how long it sets its Transmission Opportunity (TXOP), according to the information transmitted by the access point to the station. It is implemented for wireless QoS between RF media.

This blog post describes how the QoS works in case of WMM.

Finally, this slide from Cisco shows how it will all fit together.

Further reading:

• CWAP – MAC Header : QoS Control
• Mobile Traffic Engineering with Application Visibility and Control (AVC) - Cisco
• Calling VoWiFi... The Next Mobile Operator Service is here... - Cisco

QCI Enhancements For Mission Critical Communications

Its been quite a while since I posted about QCI and end-to-end bearer QoS in EPC. In LTE Release-12 some new QCI values were added to handle mission critical communications.

This picture is taken from a new blog called Public Safety LTE. I have discussed about the Default and Dedicated bearers in an earlier post here (see comments in that post too). You will notice in the picture above that new QCI values 65, 66, 69 & 70 have been added. For mission critical group communications new default bearer 69 would be used for signalling and dedicated bearer 65 will be used for data. Mission critical data would also benefit by using QCI 70.

LTE for Public Safety that was published last year provides a good insight on this topic as follows:

The EPS provides IP connectivity between a UE and a packet data network external to the PLMN. This is referred to as PDN connectivity service. An EPS bearer uniquely identifies traffic flows that receive a common QoS treatment. It is the level of granularity for bearer level QoS control in the EPC/E-UTRAN. All traffic mapped to the same EPS bearer receives the same bearer level packet forwarding treatment. Providing different bearer level packet forwarding treatment requires separate EPS bearers.

An EPS bearer is referred to as a GBR bearer, if dedicated network resources related to a Guaranteed Bit Rate (GBR) are permanently allocated once the bearer is established or modified. Otherwise, an EPS bearer is referred to as a non-GBR bearer.

Each EPS bearer is associated with a QoS profile including the following data:
• QoS Class Identifier (QCI): A scalar pointing in the P-GW and eNodeB to node-specific parameters that control the bearer level packet forwarding treatment in this node.
• Allocation and Retention Priority (ARP): Contains information about the priority level, the pre-emption capability, and the pre-emption vulnerability. The primary purpose of the ARP is to decide whether a bearer establishment or modification request can be accepted or needs to be rejected due to resource limitations.
• GBR: The bit rate that can be expected to be provided by a GBR bearer.
• Maximum Bit Rate (MBR): Limits the bit rate that can be expected to be provided by a GBR bearer.

Following QoS parameters are applied to an aggregated set of EPS bearers and are part of user’s subscription data:
• APN Aggregate Maximum Bit Rate (APN-AMBR): Limits the aggregate bit rate that can be expected to be provided across all non-GBR bearers and across all PDN connections associated with the APN.
• UE Aggregate Maximum Bit Rate (UE-AMBR): Limits the aggregate bit rate that can be expected to be provided across all non-GBR bearers of a UE. The UE routes uplink packets to the different EPS bearers based on uplink packet filters assigned to the bearers while the P-GW routes downlink packets to the different EPS bearers based on downlink packet filters assigned to the bearers in the PDN connection.

Figure 1.5 above shows the nodes where QoS parameters are enforced in the EPS system.

Related links:

• LTE QoS and prioritization for mission critical communication
• LTE QCI and End-to-end bearer QoS in EPC
• VoLTE Bearers
• New book by Nokia experts on LTE for Public Safety a must read

4G / LTE by stealth

In the good old days when people used to have 2G phones, they were expensive but all people cared about is Voice & SMS.

The initial 3G phones were bulky/heavy with small battery life, not many apps and expensive. There was not much temptation to go and buy one of these, unless it was heavily subsidised by someone. Naturally it took a while before 3G adoption became common. In the meantime, people had to go out of their way to get a 3G phone.

With 4G, it was a different story. Once LTE was ready, the high end phones started adding 4G in their phones by default. What it meant was that if the operator enabled them to use 4G, these devices started using 4G rather than 3G. Other lower end devices soon followed suit. Nowadays, unless you are looking for a real cheap smartphone, your device will have basic LTE support, maybe not advanced featured like carrier aggregation.

The tweets below do not surprise me at all:

Another data point for Turkey #4.5G: There were 5 million new LTE subscriber additions on the first *day* of launch. (no 4G before)

— Dimitris Mavrakis (@dmavrakis) May 10, 2016

With Huawei in Istanbul for a 4.5G event. Apparently there are 40 million 4G subscribers 1 month after LTE launch (by all 3 MNOs).

— Dimitris Mavrakis (@dmavrakis) May 10, 2016

This is what I refer to as 4G or LTE by stealth.

Occasionally people show charts like these (just using this as a reference but not pin pointing anyone) to justify the 5G growth trajectory with 4G in mind. It will all depend on what 5G will mean, how the devices look like, what data models are on offer, what the device prices are like, etc.

I think its just too early to predict if there will be a 5G by stealth.

State of LTE & Connectivity

There are some reports that have been recently published on connectivity and connection numbers. This post intends to provide this info.

Facebook released "State of connectivity 2015" report. As can be seen in the picture above, at the end of 2015, estimates showed that 3.2 billion people were online. This increase (up from 3 billion in 2014) is partly attributed to more affordable data and rising global incomes in 2014. Over the past 10 years, connectivity increased by approximately 200 to 300 million people per year.

While this is positive news in terms of growth, it also means that globally, 4.1 billion people were still not internet users in 2015.

The four key barriers to internet access include:

Availability: Proximity of the necessary infrastructure required for access.
Affordability: The cost of access relative to income.
Relevance: A reason for access, such as primary language content.
Readiness: The capacity to access, including skills, awareness and cultural acceptance.

The PDF version of report is available here.

The number of LTE users crossed 1 Billion, end of 2015 according to a report by GSA. OpenSignal has a summary blog post on this here.

Finally, Open Signal has published Global State of LTE Market report that provides coverage, speeds and a lot more information.

South Korea and Singapore have set themselves apart from the main body of global operators, providing both superior coverage and speed. The biggest standouts were South Korea’s Olleh and Singapore’s Singtel. Olleh excelled in coverage, but also provided one of the fastest connections speeds in our report, 34 Mbps. Meanwhile Singtel hit the 40 Mbps mark in speed while still maintaining a coverage rating of 86%. There are other notable country clusters in the upper right-hand quadrant as well, for instance operators from the Netherlands, Canada and Hungary.

Meanwhile, other countries have staked positions for themselves in specific regions of the plot. U.S. and Kuwaiti operators are tightly clustered in the lower right, meaning they offer excellent coverage but poor 4G speeds. Japan and Taiwan congregate in the middle far right with their exceptional coverage but only average speeds. Most of New Zealand and Romania’s operators hover at the center top of the chart, indicating impressive bandwidth but a general lack of availability.

Its makes interesting reading, PDF available here.

*** Added Later: 25/03/16:12.15 ***

A good breakdown of LTE subscriptions by countries by Ovum:

Quick Summary of LTE Voice Summit 2015 (#LTEVoice)

Last year's summary of the LTE voice summit was very much appreciated so I have created one this year too.

The status of VoLTE can be very well summarised as can be seen in the image above.

‘VoLTE network deployment is the one of the most difficult project ever, the implementation complexity and workload is unparalleled in history’ - China Mobile group vice-president Mr.Liu Aili

Surprisingly, not many presentations were shared so I have gone back to the tweets and the pictures I took to compile this report. You may want to download the PDF from slideshare to be able to see the links. Hope you find it useful.

Related links:

• VoLTE Roaming with RAVEL (Roaming Architecture for Voice over IMS with Local Breakout)
• S8HR: Standardization of New VoLTE Roaming Architecture
• VoLTE Roaming: LBO, S8HR or HBO

3GPP Release-13 whitepapers and presentations

With 3GPP Release-13 due early/mid next year, there has been a flurry of presentations and whitepapers on this topic. This post provides some of these. I will try and maintain a list of whitepapers/presentations as part of this post as and when released.

1. June 2015: LTE Release 13 and road to 5G - Presented by Dino Flore, Chairman of 3GPP RAN, (Qualcomm Technologies Inc.)

2. Sep 2015: Executive Summary - Inside 3GPP Release 13 by 4G Americas

3. June 2015: Mobile Broadband Evolution Towards 5G: 3GPP Rel-12 & Rel-13 and Beyond by 4G Americas

4. April 2015: LTE release 13 – expanding the Networked Society by Ericsson

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

Diameter Security is worse than SS7 Security?

Back in December last year, there was a flurry of news about SS7 security flaw that allowed hackers to snoop on an unsuspecting users calls and SMS. The blog readers will also be aware that SS7 is being replaced by the Diameter protocol. The main reason being to simplify roaming while at the same time being able to manage the signalling storm in the networks.


The bad news is that while is case of SS7, security issues are due to network implementation and configuration (above pic), the security issues in Diameter seem to be due to the protocol and architecture themselves (below pic)

Diameter is very important for LTE network architecture and will possibly continue in the future networks too. It is very important to identify all such issues and iron them before some hackers start exploiting the network vulnerabilities causing issues for everyone.

The presentation by Cédric Bonnet, Roaming Technical Domain Manager, Orange at Signalling Focus Day of LTE World Summit 2015 is embedded below:

From SS7 to Diameter Security from Zahid Ghadialy

Some important information from this post has been removed due to a valid complaint.

LTE vs TETRA for Critical Communications

Sometime back I was reading this interview between Martin Geddes and Peter Clemons on 'The Crisis in UK Critical Communications'. If you haven't read it, I urge you to read it here. One thing that stuck out was as follows:

LTE was not designed for critical communications.

Commercial mobile operators have moved from GSM to UMTS to WCDMA networks to reflect the strong growth in demand for mobile data services. Smartphones are now used for social media and streaming video. LTE technology fulfils a need to supply cheap mass market data communications.

So LTE is a data service at heart, and reflects the consumer and enterprise market shift from being predominantly voice-centric to data-centric. In this wireless data world you can still control quality to a degree. So with OFDM-A modulation we have reduced latency. We have improved how we allocate different resource blocks to different uses.

The marketing story is that we should be able to allocate dedicated resources to emergency services, so we can assure voice communications and group calling even when the network is stressed. Unfortunately, this is not the case. Even the 3GPP standards bodies and mobile operators have recognised that there are serious technology limitations.

This means they face a reputational risk in delivering a like-for-like mission-critical voice service.

Won’t this be fixed by updated standards?

The TETRA Critical Communications association (TCCA) began to engage with the 3GPP standards process in 2012. 3GPP then reached out to peers in the USA and elsewhere: the ESMCP project here in the UK, the US FirstNet programme, and the various European associations.

These lobbied 3GPP for capabilities specifically aimed at critical communications requirements. At the Edinburgh meeting in September 2014, 3GPP set up the SA6specification group, the first new group in a decade.

The hope is that by taking the critical communications requirement into a separate stream, it will no longer hold up the mass market release 12 LTE standard. Even with six meetings a year, this SA6 process will be a long one. By the end of the second meeting it had (as might be expected) only got as far as electing the chairman.

It will take time to scope out what can be achieved, and develop the critical communications functionality. For many players in the 3GPP process this is not a priority, since they are focusing solely on mass market commercial applications.

Similar point was made in another Critical communications blog here:

LTE has emerged as a long term possible replacement for TETRA in this age of mobile broadband and data. LTE offer unrivalled broadband capabilities for such applications as body warn video streaming, digital imaging, automatic vehicle location, computer-assisted dispatch, mobile and command centre apps, web access, enriched e-mail, mobile video surveillance apps such as facial recognition, enhanced Telemetry/remote diagnostics, GIS and many more. However, Phil Kidner, CEO of the TCCA pointed out recently that it will take many LTE releases to get us to the point where LTE can match TETRA on key features such as group working, pre-emptive services, network resilience, call set-up times and direct mode.

The result being, we are at a point where we have two technologies, one offering what end users want, and the other offering what end users need. This has altered the discussion, where now instead of looking at LTE as a replacement, we can look at LTE as a complimentary technology, used alongside TETRA to give end users the best of both worlds. Now the challenge appears to be how we can integrate TETRA and LTE to meet the needs and wants of our emergency services, and it seems that if we want to look for guidance and lessons on the possible harmony of TETRA and LTE we should look at the Middle East.

While I was researching, I came across this interesting presentation (embedded below) from the LTE World Summit 2015





The above is an interesting SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis for TETRA and LTE. While I can understand that LTE is yet unproven, I agree on the lack of spectrum and appropriate bands.

I have been told in the past that its not just the technology which is an issue, TETRA has many functionalities that would need to be duplicated in LTE.



As you can see from this timeline above, while Rel-13 and Rel-14 will have some of these features, there are still other features that need to be included. Without which, safety of the critical communication workers and public could be compromised.

The complete presentation as follows. Feel free to voice your opinions via comments.

Comparing LTE with TETRA etc. digital PMR for Critical Communications from Zahid Ghadialy

LTE-Broadcast making a push while Terrestrial broadcast still popular as ever

"TV isn't dying, it's having babies." This quote made my day. I have argued a few times in the past that terrestrial broadcasting will continue working and will be probably the most popular approach for a long time to come. The way things work with it may change. Multi-screen is one possible approach but you may have more interactions like 'red button functionality', etc.

Anyway, in Europe 800MHz spectrum has been cleared for use by Mobile Broadband technologies (LTE mainly). 700MHz is planned to be cleared as well by 2020, as per the suggestion in Lamy report. The other UHF band from 470MHz to 694MHz would be left as it is until 2030, with a review planned in 2025.

This has forced even big players like BBC to start looking at other mechanisms to deliver TV. While BBC3 was moved to online only, BBC is also exploring how to use LTE-Multicast to deliver content. It has been working to have its very popular iPlayer work with eMBMS.

Embedded below is a presentation from Cambridge Wireless CWTEC 2015 conference.

eMBMS is gaining popularity with its presence in lot more chipsets and even more trials. GSA report has shown that there are quite a few trials going on worldwide but the question remains about the business models. Most operators would not like to become content providers and compete with the incumbents in their markets. Having someone like BBC in the UK is helpful but not sure how many such options are available worldwide. Embedded below is the GSA presentation

GSA: LTE Broadcast (eMBMS) Update - March 2015 from Zahid Ghadialy

Great LTE Broadcast demo by @Ericsson using devices from Samsung & LG powered by Qualcomm. Consumers will love this. pic.twitter.com/1uroaV3mk9

— Ben Wood (@benwood) March 5, 2015

There were some nice pictures from MWC as can be seen above. Ericsson has a video as well (below) on how the app works.

M2M LTE Broadcast module fm D-Link / Verizon. Huge potential here for billboards, taxis or any screen U can think of! pic.twitter.com/WL2f5mZ5bB

— Ben Wood (@benwood) March 5, 2015

D-Link is also working on M2M modules that could be used in billboards to dynamically update the ads at very regular intervals. There is a video here that explains this further.

Finally here is a Video from Visteon/Verizon that explains how LTE-Multicast can be used to deliver software updates in the connected car:



Finally, here are couple of presentations that may interest you too:

• Delivery of Broadcast Content over LTE Networks
• Transitioning from Broadcast TV to Broadband TV

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

3GPP Release-13 work started in earnest

The 3GPP news from some months back listed the main RAN features that have been approved for Release-13 and the work has already started on them. The following are the main features (links contain .zip files):

• LTE in unlicensed spectrum (aka Licensed-Assisted Access) - RP-150055
• Carrier Aggregation enhancements - RP-142286
• LTE enhancements for Machine-Type Communications (MTC) - RP-141865
• Enhancements for D2D - RP-142311
• Study Item Elevation Beamforming / Full-Dimension MIMO - RP-141831
• Study Item Enhanced multi-user transmission techniques - RP-142315
• Study Item Indoor positioning - RP-141102
• Study Item Single-cell Point-to-Multipoint (SC-PTM) - RP-142205

Another 3GPP presentation from late last year showed the system features that were being planned for Rel-13 as shown above.

I have also posted a few items earlier relating to Release13, as follows:

• LTE Category-0 low power M2M devices
• Update on Public Safety and Mission Critical communications
• 3GPP Rel-12 and Future Security Work
• Elevation Beamforming / Full-Dimension MIMO
• LA-LTE and LAA
• LTE-Hetnet (LTE-H) a.k.a. LTE Wi-Fi Link Aggregation (LWA)

Ericsson has this week published a whitepaper on release 13, with a vision for 'Networked Society':

The vision of the Networked Society, where everything that benefits from being connected will be connected, places new requirements on connectivity. LTE is a key component in meeting these demands, and LTE release 13 is the next step in the LTE evolution.

Their whitepaper embedded below:

It should be pointed out that 5G work does not start until Release-15 as can be seen from my tweet

Nice picture of "5G Radio Interface development timeline" by @alainmouradUK pic.twitter.com/ANFfujJGS5
— Zahid Ghadialy (@zahidtg) April 4, 2015

xoxoxo Added Later (26/04/2015) xoxoxo
I came across this presentation from Keysight (Agilent) where Moray Rumney has provided information in much more detail.

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.

Air-Ground-Air communications in Mission Critical scenarios

In-flight communications have always fascinated me. While earlier the only possibility was to use Satellites, a hot topic for in the last few years has been Air-Ground-Air communications.

Some of you may remember that couple of years back Ericsson showed an example of using LTE in extreme conditions. The video below shows that LTE can work in these scenarios.



Now there are various acronyms being used for these type of communications but the one most commonly used is Direct-Air-to-Ground Communications (DA2GC), Air-to-Ground (A2G) and Ground-to-Air (G2A).

While for short distance communications, LTE or any cellular technology (see my post on Flying Small Cells) may be a good option, a complete solution including communication over sea would require satellite connectivity as well. As I have mentioned in a blog post before, 75Mbps connectivity would soon be possible with satellites.

For those interested in working of the Air-Ground-Air communications, would find the presentation below useful. A much detailed ECC CEPT report from last year is available here.

Direct Air-to-Ground Communication – Broadband for Planes from Zahid Ghadialy

The next challenge is to explore whether LTE can be used for Mission Critical Air Ground Air communications. 3GPP TSG RAN recently conducted study on the feasibility and the conclusions are as follows:

There is a common understanding from companies interested in the topic that:

1. Air-to-Ground communications can be provided using the LTE standards (rel-8 and beyond depending on the targeted scenarios).
2. 3GPP UE RF requirements might need to be adapted
3. It may be possible to enhance the performance of the communications with some standards changes, but these are in most cases expected to be non-fundamental optimizations
4. Engineering and implementation adaptations are required depending on the deployment scenario. In particular, the ECC report [1] comments that from implementation point of view synchronization algorithms are to be modified compared to terrestrial mobile radio usage in order to cope with high Doppler frequency shift of the targeted scenario. In addition, some network management adaptations might be needed. From engineering perspective the Ground base station antenna adjustment has to be matched to cover indicated aircraft heights above ground up to 12 km by antenna up-tilt. It is also expected that the inter-site distances would be dominated by the altitudes to be supported [5].
5. A2G technology using legacy LTE has been studied and successfully trialed covering different kinds of services: Surfing, downloading, e-mail transmission, use of Skype video, audio applications and Video conferencing. Related results can be found in several documents from ECC and from companies [1], [2], [3]. The trials in [1] and [2] assumed in general a dedicated spectrum, and the fact that the communications in the aircraft cabin are using WIFI or GSMOBA standards, while LTE is used for the Broadband Direct-Air-to-Ground connection between the Aircraft station and the Ground base station.
6. It is understood that it is possible to operate A2G communications over spectrum that is shared with ground communications. However, due to interference it is expected that the ground communications would suffer from capacity losses depending on the deployment scenario. Therefore, it is recommended to operate A2G communication over a dedicated spectrum.
7. It can be noted that ETSI studies concluded that Spectrum above 6 GHz is not appropriate for such applications [4].
8. LTE already provides solutions to allow seamless mobility in between cells. Cells can be intended for terrestrial UEs and cells intended for A2G UEs which might operate in different frequencies.
9. Cell range in LTE is limited by the maximum timing advance (around 100km). Larger ranges could be made possible by means of implementation adaptations. 

LTE Category-0 low power M2M devices

While we have talked about different LTE categories, especially higher speeds, we have not yet discussed Category-0 or Cat-0 for M2M.

A recent news report stated the following:

CAT-1 and CAT-0 are lower speed and power versions of the LTE standard which dramatically extend the addressable market for carriers and chip makers alike. They introduce new IoT targeted features, extend battery operation and lower the cost of adding LTE connectivity.

“While chipsets supporting these lower categories are essential for numerous applications, including wearable devices, smart home and smart metering, there has been an industry development gap that we had anticipated two years ago,” said Eran Eshed, co-founder and vice president of marketing and business development at Altair. “We’ve worked hard to address this gap by being first to market with true CAT-1 and 0 chipsets featuring a power/size/cost combination that is a massive game-changer.”

Ericsson has an interesting presentation that talks about LTE evolution for cellular IoT. While Rel-12 Cat-0 would use the normal allocated bandwidth (upto 20MHz), Rel-13 plans further enhancements to save even more power by reducing the bandwidth to 1.4Mhz. Another possible saving of power comes from the use of Half Duplex (but its optional). There is a very interesting presentation from Mstar semiconductors on half duplex that I have blogged about here. Anyway, the presentation from Ericsson is here:

When we talk about 50 billion M2M devices, a question that I regularly ask is how many of them will be using cellular and how many will use other technologies. Its good to see that my skepticism is shared by others as well, see the tweet below.

@disruptivedean @ericsson Re 2% only cellular, I was discussing this the other day. Too many competing techs. pic.twitter.com/Z7s6wqxkBM
— Zahid Ghadialy (@zahidtg) January 26, 2015

Click on the pic.twitter.com/Z7s6wqxkBM to see the actual media.

Nokia has also got an interesting whitepaper on this topic which talks about optimizing LTE and the architectural evolution that will lead cellular LTE to become a compelling technology so that it can be widely adopted. That paper is embedded as well below.

Nokia LTE M2M: Optimizing LTE for the Internet of Things from Zahid Ghadialy