Showing posts with label LTE. Show all posts
Showing posts with label LTE. Show all posts

Thursday 4 January 2018

Introduction to 3GPP Security in Mobile Cellular Networks


I recently did a small presentation on 3GPP Security, looking at the how the security mechanism works in mobile cellular networks; focusing mainly on signaling associated with authentication, integrity protection and ciphering / confidentiality. Its targeted towards people with basic understanding of mobile networks. Slides with embedded video below.



You can also check-out all such videos / presentations at the 3G4G training section.

Friday 22 December 2017

The small detail about 5G you may have missed...


While going through the latest issue of CW Journal, I came across this article from Moray Rumney, Lead Technologist, Keysight. It highlights an interesting point that I missed out earlier that 5G also includes all LTE specifications from Release 15 onwards.

I reached out to our CW resident 3GPP standards expert Sylvia Lu to clarify and received more details.
There is a whole lot of detail available in RP-172789.zip. Here RIT stands for Radio Interface Technology and SRIT for Set of RIT.

In fact at Sylvia clarified, NB-IoT and Cat-M will also be part of the initial IMT-2020 submissions early next year. Thanks Sylvia.


There is also this nice presentation by Huawei in ITU (here) that describes Requirements, Evaluation Criteria and Submission Templates for the development of IMT-2020. It is very helpful in understanding the process.

Coming back to the question I have often asked (see here for example),
1. What features are needed for operator to say they have deployed 5G, and
2. How many sites / coverage area needed to claim 5G rollout

With LTE Release-15 being part of 5G, I think it has just become easy for operators to claim they have 5G.

What do you think?

Monday 18 December 2017

Control and User Plane Separation of EPC nodes (CUPS) in 3GPP Release-14


One of the items in 3GPP Rel-14 is Control and User Plane Separation of EPC nodes (CUPS). I have made a video explaining this concept that is embedded below.

In 3G networks (just considering PS domain), the SGSN and GGSN handles the control plane that is responsible for signalling as well as the user plane which is responsible for the user data. This is not a very efficient approach for deployment.

You can have networks that have a lot of signalling (remember signaling storm?) due to a lot of smartphone users but not necessarily consuming a lot of data (mainly due to price reasons). On the other hand you can have networks where there is not a lot of signalling but lot of data consumption. An example of this would be lots of data dongles or MiFi devices where users are also consuming a lot of data, because it’s cheap.

To cater for these different scenarios, the control plane and user plane was separated to an extent in the Evolved Packet Core (EPC). MME handles the control plane signalling while S-GW & P-GW handles the user plane

CUPS goes one step further by separating control & user plane from S-GW, P-GW & TDF. TDF is Traffic Detection Function which was introduced together with Sd reference point as means for traffic management in the Release 11. The Sd reference point is used for Deep Packet Inspections (DPI) purposes. TDF also provides the operators with the opportunity to capitalize on analytics for traffic optimization, charging and content manipulation and it works very closely with Policy and charging rules function, PCRF.

As mentioned, CUPS provides the architecture enhancements for the separation of S-GW, P-GW & TDF functionality in the EPC. This enables flexible network deployment and operation, by using either distributed or centralized deployment. It also allows independent scaling between control plane and user plane functions - while not affecting the functionality of the existing nodes subject to this split.

As the 3GPP article mentions, CUPS allows for:
  • Reducing Latency on application service, e.g. by selecting User plane nodes which are closer to the RAN or more appropriate for the intended UE usage type without increasing the number of control plane nodes.
  • Supporting Increase of Data Traffic, by enabling to add user plane nodes without changing the number of SGW-C, PGW-C and TDF-C in the network.
  • Locating and Scaling the CP and UP resources of the EPC nodes independently.
  • Independent evolution of the CP and UP functions.
  • Enabling Software Defined Networking to deliver user plane data more efficiently.

The following high-level principles were also adopted for the CUPS:
  • The CP function terminates the Control Plane protocols: GTP-C, Diameter (Gx, Gy, Gz).
  • A CP function can interface multiple UP functions, and a UP function can be shared by multiple CP functions.
  • An UE is served by a single SGW-CP but multiple SGW-UPs can be selected for different PDN connections. A user plane data packet may traverse multiple UP functions.
  • The CP function controls the processing of the packets in the UP function by provisioning a set of rules in Sx sessions, i.e. Packet Detection Rules for packets inspection, Forwarding Action Rules for packets handling (e.g. forward, duplicate, buffer, drop), Qos Enforcement Rules to enforce QoS policing on the packets, Usage Reporting Rules for measuring the traffic usage.
  • All the 3GPP features impacting the UP function (PCC, Charging, Lawful Interception, etc) are supported, while the UP function is designed as much as possible 3GPP agnostic. For example, the UPF is not aware of bearer concept.
  • Charging and Usage Monitoring are supported by instructing the UP function to measure and report traffic usage, using Usage Reporting Rule(s). No impact is expected to OFCS, OCS and the PCRF.
  • The CP or UP function is responsible for GTP-u F-TEID allocation.
  • A legacy SGW, PGW and TDF can be replaced by a split node without effecting connected legacy nodes.
CUPS forms the basis of EPC architecture evolution for Service-Based Architecture for 5G Core Networks. More in another post soon.

A short video on CUPS below, slides available here.



Further reading:


Tuesday 12 December 2017

5G Patents Progress

More than 23,500 patents have been declared essential to the GSM & 3G as shown in the picture above. I am assuming this includes 4G as well. Anyway, its been a while I looked into this subject. The last time I was looking, 4G patent pools were beginning to form.

For LTE, indeed there is no one-stop shop for licensing. The only company that has tried is VIA Licensing, with their patent pool, but they don’t have licenses for the big players like Ericsson, Qualcomm, Huawei, ZTE, Samsung, etc. The same will probably apply for 5G.


This old picture and article from Telecom TV (link) is an interesting read on this topic.



This official WIPO list shows ZTE, Huawei, and Qualcomm at the top of the list for international patent filers worldwide in 2016 [PDF].

Back in 2015, NGMN alliance was also looking for creation of some kind of patent pool but it probably didn't go anywhere (link)

(Can't recall the source for this one) In March, Ericsson announced plans to license 5G for $5 per device and possibly as low as $2.50 in emerging markets. In November, Qualcomm announced plans to license 5G IP at the same rates established by the NDRC for 4G/LTE phones sold into China: 2.275% for single mode essential patents / 4.0% for the entire portfolio or 3.25% for multimode essential patents / 5.0% for the entire portfolio. All rates are based on the wholesale price of the phone.

Qualcomm also announced that the previously undisclosed $500 price cap will apply to all phones. Qualcomm also announce a rate of less than $5 for 5G for automotive applications and $0.50 for NB-IoT based IoT applications.

Ericsson has filed patent application for its end-to- end 5G technology. Ericsson has incorporated its numerous 5G and related inventions into a complete architecture for the 5G network standard. The patent application filed by the leading telecom vendor combines the work of 130 Ericsson inventors.

Dr. Stefan Parkvall, Principal Researcher at Ericsson, said, “The patent application contains Ericsson’s complementary suite of 5G inventions.” Stefan added, “It contains everything you need to build a complete 5G network. From devices, the overall network architecture, the nodes in the network, methods and algorithms, but also shows how to connect all this together into one fully functioning network. The inventions in this application will have a huge impact on industry and society: they will provide low latency with high performance and capacity.

This will enable new use cases like the Internet of Things, connected factories and self-driving cars.” Ericsson is involved with leading mobile operators across the world for 5G and Pre-5G research and trials. The patent application is likely to further strengthen its position in the 5G race.

More details on E/// 5G patents on their official website here.

Mobile world live has some good details on Qualcomm 5G NR royalty terms.

Smartphone vendors will have to pay as much as $16.25 per device to use Qualcomm’s 5G New Radio (NR) technology under new royalty guidelines released by the company.

Qualcomm said it will implement a royalty rate of 2.275 per cent of the selling price for single-mode 5G handsets and a higher rate of 3.25 per cent for multi-mode smartphones with 3G, 4G and 5G capabilities.

So for a $200 multi-mode device, for instance, Qualcomm noted a vendor would have to pay $6.50 in royalties per device. Royalties are capped at a $500 device value, meaning the maximum amount a smartphone vendor would have to pay would be $16.25 per handset.

The company added it will also offer access to its portfolio of both cellular standard essential patents and non-essential patents at a rate of 4 per cent of the selling price for single-mode devices and 5 per cent for multi-mode devices.

Qualcomm’s rates are notably higher than those announced by Ericsson in March. The Swedish company said it would charge a flat royalty fee of $5 per 5G NR multimode handset, but noted its fee could go as low as $2.50 per device for handsets with low average selling prices.

The official Qualcomm 5G royalty terms [PDF] are available here.

Further reading:


Thanks to Mike Saji for providing inputs on 4G patent landscape. Thanks to Keith Dyer for interesting tweets on this topic.

Thursday 23 November 2017

5G NR Radio Protocols and Tight Inter-working with LTE


Osman Yilmaz, Team Leader & Senior Researcher at Ericsson Research in Finland gave a good summary of 5G NR at URLLC 2017 Conference (see summary here). His presentation is embedded below:



Osman, along with Oumer Teyeb, Senior Researcher at Ericsson Research & member of the Ericsson 5G standardization delegation has also published a blog post LTE-NR tight-interworking on Ericsson Research blog.

The post talks about how how signalling and data will work in LTE & New Radio (NR) dual connected devices. In control plane it looks at RRC signalling applicable for this DC devices whereas in user plane it looks at direct and split DRB options.


Further details here.

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

5.1.2.2 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.

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.

Friday 8 September 2017

Debugging Problem: Same Phones With Different Signal Levels?

I have discussed this problem in past, based on questions asked on various fora (example). Here is a video I made some weeks back. Will be interested to know what other reasons people can come up with ðŸ˜Š.


Friday 7 July 2017

Wireless Smart Ubiquitous Network (Wi-SUN) - Another IoT Standard


While we have been discussing IoT these last few weeks, here is another one that I came across. This picture above from a recent Rethink research shows that Wi-SUN is going to enjoy more growth than LoRaWAN or Sigfox. Another recent report by Mobile Experts also makes a mention of this IoT technology.

I am sure most of the readers have not heard of Wi-SUN, so what exactly is Wi-SUN technology?


From Rethink Research, The Wi-SUN Alliance was formed in 2011 to form an organization to push adoption of the IEEE 802.15.4g standard, which aimed to improve utility networks using a narrowband wireless technology. The peer-to-peer self-healing mesh has moved from its initial grid focus to encompass smart city applications (especially street lighting), and we spoke to its Chairman, Phil Beecher, to learn more.

Beecher explained that the non-profit Alliance set about defining subsets of the open standards, testing for interoperability, and certifying compatible products, and soon developed both a Field Area Network (FAN) and a Home Area Network (HAN), which allowed it to move into Home Energy Management Systems (HEMS) in Japan – a country that is leading the curve in HEMS deployments and developments.


As can be seen in the picture above:

  • Develops technical specifications of Physical Layer (PHY) and Medium Access Control (MAC) layers, with Network layer as required
  • Develop Interoperability test programs to ensure implementations are interoperable
  • Physical layer specification is based on IEEE802.15.4g/4u/4v
  • MAC layer may use different options depending on the application
  • Profile specifications are categorized based on application types

Picture source for the last three pics, Wi-SUN presentation here.


A new whitepaper from Wi-SUN Alliance provides comparison of Wi-SUN, LoRaWAN and NB-IoT.

A recent presentation by Dr. Simon Dunkley in Cambridge Wireless is embedded below:



Further reading:



Monday 19 June 2017

Network Sharing is becoming more relevant with 5G

5G is becoming a case of 'damned if you do damned if you don't'. Behind the headlines of new achievements and faster speeds lies the reality that many operators are struggling to keep afloat. Indian and Nigerian operators are struggling with heavy debt and it wont be a surprise if some of the operators fold in due course.

With increasing costs and decreasing revenues, its no surprise that operators are looking at ways of keeping costs down. Some operators are postponing their 5G plans in favour of Gigabit LTE. Other die hard operators are pushing ahead with 5G but looking at ways to keep the costs down. In Japan for example, NTT DOCOMO has suggested sharing 5G base stations with its two rivals to trim costs, particularly focusing efforts in urban areas.


In this post, I am looking to summarise an old but brilliant post by Dr. Kim Larsen here. While it is a very well written and in-depth post, I have a feeling that many readers may not have the patience to go through all of it. All pictures in this post are from the original post by Dr. Kim Larsen.


Before embarking on any Network sharing mission, its worthwhile asking the 5W's (Who, Why, What, Where, When) and 2H's (How, How much).

  • Why do you want to share?
  • Who to share with? (your equal, your better or your worse).
  • What to share? (sites, passives, active, frequencies, new sites, old sites, towers, rooftops, organization, ,…).
  • Where to share? (rural, sub-urban, urban, regional, all, etc..).
  • When is a good time to start sharing? During rollout phase, steady phase or modernisation phase. See picture below. For 5G, it would make much more sense that network sharing is done from the beginning, i.e., Rollout Phase


  • How to do sharing?. This may sound like a simple question but it should take account of regulatory complexity in a country. The picture below explains this well:



  • How much will it cost and how much savings can be attained in the long term? This is in-fact a very important question because the end result after a lot of hard work and laying off many people may result in an insignificant amount of cost savings. Dr. Kim provides detailed insight on this topic that I find it difficult to summarise. Best option is to read it on his blog.


An alternative approach to network sharing is national roaming. Many European operators are dead against national roaming as this means the network loses its differentiation compared to rival operators. Having said that, its always worthwhile working out the savings and seeing if this can actually help.

National Roaming can be attractive for relative low traffic scenarios or in case were product of traffic units and national roaming unit cost remains manageable and lower than the Shared Network Cost.

The termination cost or restructuring cost, including write-off of existing telecom assets (i.e., radio nodes, passive site solutions, transmission, aggregation nodes, etc….) is likely to be a substantially financial burden to National Roaming Business Case in an area with existing telecom infrastructure. Certainly above and beyond that of a Network Sharing scenario where assets are being re-used and restructuring cost might be partially shared between the sharing partners.

Obviously, if National Roaming is established in an area that has no network coverage, restructuring and termination cost is not an issue and Network TCO will clearly be avoided, Albeit the above economical logic and P&L trade-offs on cost still applies.

If this has been useful to understand some of the basics of network sharing, I encourage you to read the original blog post as that contains many more details.

Futher Reading:



Monday 1 May 2017

Variety of 3GPP IoT technologies and Market Status - May 2017



I have seen many people wondering if so many different types of IoT technologies are needed, 3GPP or otherwise. The story behind that is that for many years 3GPP did not focus too much on creating an IoT variant of the standards. Their hope was that users will make use of LTE Cat 1 for IoT and then later on they created LTE Cat 0 (see here and here).

The problem with this approach was that the market was ripe for a solution to a different types of IoT technologies that 3GPP could not satisfy. The table below is just an indication of the different types of technologies, but there are many others not listed in here.


The most popular IoT (or M2M) technology to date is the humble 2G GSM/GPRS. Couple of weeks back Vodafone announced that it has reached a milestone of 50 million IoT connections worldwide. They are also adding roughly 1 million new connections every month. The majority of these are GSM/GPRS.

Different operators have been assessing their strategy for IoT devices. Some operators have either switched off or are planning to switch off they 2G networks. Others have a long term plan for 2G networks and would rather switch off their 3G networks to refarm the spectrum to more efficient 4G. A small chunk of 2G on the other hand would be a good option for voice & existing IoT devices with small amount of data transfer.

In fact this is one of the reasons that in Release-13 GSM is being enhanced for IoT. This new version is known as Extended Coverage – GSM – Internet of Things (EC-GSM-IoT ). According to GSMA, "It is based on eGPRS and designed as a high capacity, long range, low energy and low complexity cellular system for IoT communications. The optimisations made in EC-GSM-IoT that need to be made to existing GSM networks can be made as a software upgrade, ensuring coverage and accelerated time to-market. Battery life of up to 10 years can be supported for a wide range use cases."

The most popular of the non-3GPP IoT technologies are Sigfox and LoRa. Both these technologies have gained significant ground and many backers in the market. This, along with the gap in the market and the need for low power IoT technologies that transfer just a little amount of data and has a long battery life motivated 3GPP to create new IoT technologies that were standardised as part of Rel-13 and are being further enhanced in Rel-14. A summary of these technologies can be seen below


If you look at the first picture on the top (modified from Qualcomm's original here), you will see that these different IoT technologies, 3GPP or otherwise address different needs. No wonder many operators are using the unlicensed LPWA IoT technologies as a starting point, hoping to complement them by 3GPP technologies when ready.

Finally, looks like there is a difference in understanding of standards between Ericsson and Huawei and as a result their implementation is incompatible. Hopefully this will be sorted out soon.


Market Status:

Telefonica has publicly said that Sigfox is the best way forward for the time being. No news about any 3GPP IoT technologies.

Orange has rolled out LoRa network but has said that when NB-IoT is ready, they will switch the customers on to that.

KPN deployed LoRa throughout the Netherlands thereby making it the first country across the world with complete coverage. Haven't ruled out NB-IoT when available.

SK Telecom completed nationwide LoRa IoT network deployment in South Korea last year. It sees LTE-M and LoRa as Its 'Two Main IoT Pillars'.

Deutsche Telekom has rolled out NarrowBand-IoT (NB-IoT) Network across eight countries in Europe (Germany, the Netherlands, Greece, Poland, Hungary, Austria, Slovakia, Croatia)

Vodafone is fully committed to NB-IoT. Their network is already operational in Spain and will be launching in Ireland and Netherlands later on this year.

Telecom Italia is in process of launching NB-IoT. Water meters in Turin are already sending their readings using NB-IoT.

China Telecom, in conjunction with Shenzhen Water and Huawei launched 'World's First' Commercial NB-IoT-based Smart Water Project on World Water Day.

SoftBank is deploying LTE-M (Cat-M1) and NB-IoT networks nationwide, powered by Ericsson.

Orange Belgium plans to roll-out nationwide NB-IoT & LTE-M IoT Networks in 2017

China Mobile is committed to 3GPP based IoT technologies. It has conducted outdoor trials of NB-IoT with Huawei and ZTE and is also trialing LTE-M with Ericsson and Qualcomm.

Verizon has launched Industry’s first LTE-M Nationwide IoT Network.

AT&T will be launching LTE-M network later on this year in US as well as Mexico.

Sprint said it plans to deploy LTE Cat 1 technology in support of the Internet of Things (IoT) across its network by the end of July.

Further reading:

Monday 16 January 2017

Gigabit LTE?


Last year Qualcomm announced the X16 LTE modem that was capable of up to 1Gbps, category 16 in DL and Cat 13 (150 Mbps) in UL. See my last post on UE categories here.


Early January, it announced Snapdragon 835 at CES that looks impressive. Android central says "On the connectivity side of things, there's the Snapdragon X16 LTE modem, which enables Category 16 LTE download speeds that go up to one gigabit per second. For uploads, there's a Category 13 modem that lets you upload at 150MB/sec. For Wi-Fi, Qualcomm is offering an integrated 2x2 802.11ac Wave-2 solution along with an 802.11ad multi-gigabit Wi-Fi module that tops out at 4.6Gb/sec. The 835 will consume up to 60% less power while on Wi-Fi."

Technology purists would know that LTE, which is widely referred to as 4G, was in fact pre-4G or as some preferred to call it, 3.9G. New UE categories were introduced in Rel-10 to make LTE into LTE-Advanced with top speeds of 3Gbps. This way, the ITU requirements for a technology to be considered 4G (IMT-Advanced) was satisfied.


LTE-A was already Gigabit capable in theory but in practice we had been seeing peak speeds of up to 600Mbps until recently. With this off my chest, lets look at what announcements are being made. Before that, you may want to revisit what 4.5G or LTE-Advanced Pro is here.

  • Qualcomm, Telstra, Ericsson and NETGEAR Announce World’s First Gigabit Class LTE Mobile Device and Gigabit-Ready Network. Gigabit Class LTE download speeds are achieved through a combination of 3x carrier aggregation, 4x4 MIMO on two aggregated carriers plus 2x2 MIMO on the third carrier, and 256-QAM higher order modulation. 
  • TIM in Italy is the first in Europe to launch 4.5G up to 500 Mbps in Rome, Palermo and Sanremo
  • Telenet in partnership with ZTE have achieved a download speed of 1.3 Gbps during a demonstration of the ZTE 4.5G new technology. That's four times faster than 4G's maximum download speed. Telenet is the first in Europe to reach this speed in real-life circumstances. 4.5G ZTE technology uses 4x4 MIMO beaming, 3-carrier aggregation, and a QAM 256 modulation.
  • AT&T said, "The continued deployment of our 4G LTE-Advanced network remains essential to laying the foundation for our evolution to 5G. In fact, we expect to begin reaching peak theoretical speeds of up to 1 Gbps at some cell sites in 2017. We will continue to densify our wireless network this year through the deployment of small cells and the use of technologies like carrier aggregation, which increases peak data speeds. We’re currently deploying three-way carrier aggregation in select areas, and plan to introduce four-way carrier aggregation as well as LTE-License Assisted Access (LAA) this year."
  • T-Mobile USA nearly reached a Gigabit and here is what they say, "we reached nearly 1 Gbps (979 Mbps) on our LTE network in our lab thanks to a combination of three carrier aggregation, 4x4 MIMO and 256 QAM (and an un-released handset)."
  • The other US operator Sprint expects to unveil some of its work with 256-QAM and massive MIMO on Sprint’s licensed spectrum that pushes the 1 gbps speed boundary. It’s unclear whether this will include an actual deployment of the technology

So we are going to see a lot of higher speed LTE this year and yes we can call it Gigabit LTE but lets not forget that the criteria for a technology to be real '4G' was that it should be able to do 1Gbps in both DL and UL. Sadly, the UL part is still not going Gigabit anytime soon.

Saturday 7 January 2017

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:



Sunday 6 November 2016

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:
Further Reading:



Monday 26 September 2016

QoS in VoWiFi

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



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:

Sunday 22 May 2016

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:



Saturday 14 May 2016

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:



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.