Top 10 posts for 2014

Here are the top 10 posts of 2014 from The 3G4G Blog:

1. Different flavours of SRVCC (Single Radio Voice Call Continuity) - January 2014
   
2. MNO, MVNO, MVNA, MVNE - The different types of operators - April 2014
   
3. New LTE-A UE Category 9 and 10 in Rel-11 - August 2014
   
4. 4.5G: Integration of LTE and Wi-Fi networks - June 2014
   
5. Voice over WiFi (VoWiFi) - June 2014
   
6. Further enhanced Inter-Cell Interference Coordination (FeICIC) - May 2014
   
7. VoLTE Roaming with RAVEL (Roaming Architecture for Voice over IMS with Local Breakout) - February 2014
   
8. What is (pre-5G) 4.5G? - October 2014
   
9. LA-LTE and LAA - July 2014
   
10. Multi-SIM: The Jargon - January 2014

The SS7 flaws that allows hackers to snoop on your calls and SMS

By now I am aware that most people have heard of the flaws in SS7 networks that allow hackers to snoop, re-route calls and read text messages. For anyone who is not aware of these things, can read some excellent news articles here:

• Hackers Can Read Your Texts Thanks to Huge Security Flaw - Gizmodo
• German researchers discover a flaw that could let anyone listen to your cell calls. - Washington Post
• White hats do an NSA, figure out LIVE PHONE TRACKING via protocol vuln - The Register
• 1980s technology can be used to hack any smartphone - Beta News

Our trusted security expert, Ravi Borgaonkar, informs us that all these flaws have already been discussed back in May, as part of Positive Hack Days (PHDays).

Here are the slides on SS7 hack from PHDays, http://t.co/VwUwtFVqyc mentions all flaws reveals in 3 #31c3 talks on SS7 security.
— Ravishankar Borgaonk (@raviborgaonkar) December 28, 2014

The presentation is embedded below and can be downloaded from Slideshare:

How to Intercept a Conversation Held on the Other Side of the Planet from Positive Hack Days

xoxoxo Added this new information on the 4th Jan 2015 oxoxox

The following is this presentation and video by Tobias Engel from the 31st Chaos Communication Congress

SS7: Locate. Track. Manipulate. from 3G4G

M2M embedded UICC (eSIM) Architecture and Use Cases

Machine-to-Machine UICC, also known as M2M Form Factor (MFF) and is often referred to as embedded SIM (eSIM) is a necessity for the low data rate M2M devices that are generally small, single contained unit that is also sealed. The intention is that once this M2M device is deployed, then there is no need to remove the UICC from it. There may be a necessity to change the operator for some or the other reason. This gives rise to the need of multi-operator UICC (SIM) cards.

The GSMA has Embedded SIM specifications available for anyone interested in implementing this. There are various documents available on the GSMA page for those interested in this topic further.

While the complete article is embedded below, here is an extract of the basic working from the document:

A eUICC is a SIM card with a Remote Provisioning function, and is designed not to be removed or changed. It is able to store multiple communication profiles, one of which is enabled (recognized by the device and used for communication). The network of the MNO in the enabled profile is used for communication. Profiles other than the enabled profile are disabled (not recognized by the device). With conventional SIM cards, the ICCID is used as the unique key to identify the SIM card, but with eUICC, the ICCID is the key used to identify profiles, and a new ID is defined, called the eUICCID, which is used as the unique key for the eSIM

GSMA defines two main types of profile.
1) Provisioning Profile: This is the communication profile initially stored in the eUICC when it is shipped. It is a limited-application communication profile used only for downloading and switching Operational Profiles, described next.
2) Operational Profile: This is a communication profile for connecting to enterprise servers or the Internet. It can also perform the roles provided by a Provisioning profile

An eSIM does not perform profile switching as a simple IC card function, but rather switches profiles based on instructions from equipment called a Subscription Manager. A Subscription Manager is maintained and managed by an MNO. The overall eSIM architecture, centering on the Subscription Manager, is shown in Figure 3, using the example of switching profiles within the eUICC.

An eUICC must have at least one profile stored in it to enable OTA functionality, and one of the stored profiles must be enabled. The enabled profile uses the network of MNO A for communication. When the user switches profiles, a switch instruction is sent to the Subscription Manager. At that time, if the profile to switch to is not stored in the eUICC, the profile is first downloaded. When it receives a switch instruction, the eUICC performs a switch of the enabled profile as an internal process.

After the switch is completed, it uses the network of MNO B to send notification that the switch has completed to the Subscription Manager, completing the process. The same procedure is used to switch back to the original MNO A, or to some other MNO C.

Anyway, here is the complete paper on NTT Docomo website.

5G Spectrum and challenges

I was looking at the proposed spectrum for 5G last week. Anyone who follows me on Twitter would have seen the tweets from last weekend already. I think there is more to discuss then just tweet them so here it is.

Metis has the most comprehensive list of all the bands identified from 6GHz, all the way to 86GHz. I am not exactly sure but the slide also identifies who/what is currently occupying these bands in different parts of the world.

The FCC in the USA has opened a Notice of Inquiry (NoI) for using the bands above 24GHz for mobile broadband. The frequency bands above have a potential as there is a big contiguous chunk of spectrum available in each band.

Finally, the slides from ETRI, South Korea show that they want to have 500MHz bandwidth in frequencies above 6GHz.

As I am sure we all know, the higher the frequency, the lower the cell size and penetration indoors. The advantage on the other hand is smaller cell sizes, leading to higher data rates. The antennas also become smaller at higher frequencies thereby making it easier to have higher order MIMO (and massive MIMO). The only way to reliably be able to do mobile broadband is to use beamforming. The tricky part with that is the beam has to track the mobile user which may be an issue at higher speeds.

The ITU working party 5D, recently released a draft report on 'The technical feasibility of IMT in the bands above 6 GHz'. The document is embedded below.

ITU Working Party 5D: The technical feasibility of IMT in the bands above 6 GHz from Zahid Ghadialy

xoxoxo Added Later (13/12/2014) xoxoxo
Here are some links on the related topic:

• IEEE ComSoc: 5G Wireless Demos Use High Frequencies
• HUAWEI, TELE2 disagree on role of spectrum for 5G

xoxoxo Added Later (18/12/2014) xoxoxo
Moray Rumney from Keysight (Agilent) gave a presentation on this topic in the Cambridge Wireless Mobile Broadband SIG event yesterday, his presentation is embedded below.

Bringing Network Function Virtualization (NFV) to LTE

SDN and NFV have gained immense popularity recently. Not only are they considered important for reducing the Capex and Opex but are being touted as an important cog in the 4.5G/5G network. See here for instance.

I introduced NFV to the blog nearly a year back here. ETSI had just published their first specs around then. When I talked about SDN/NFV back in May, these ETSI standards were evolving into a significant reference documents. This is a reason 4G Americas recently published this whitepaper (embedded below), for the operators to start migrating to NFV architecture to reap long term benefits. The following is from the whitepaper:

The strategies and solutions explored in the 4G Americas report on NFV aim to address these issues and others by leveraging IT virtualization technology to consolidate many network equipment types onto industry standard high volume servers, networking and storage. NFV is about separating network functions from proprietary hardware and then consolidating and running those functions as virtualized applications on a commodity server. Broadly speaking, NFV will enable carriers to virtualize network functions and run them as software applications within their networks. NFV focuses on virtualizing network functions such as firewalls, Wide-Area Network (WAN) acceleration, network routers, border controllers (used in Voice over IP (VoIP) networks), Content Delivery Networks (CDNs) and other specialized network applications. NFV is applicable to a wide variety of networking functions in both fixed and mobile networks.

“NFV is making great progress throughout the world as operators work with their vendor partners to address the opportunities of increasing efficiency within their network infrastructure elements,” stated Chris Pearson, President of 4G Americas. “There is a great deal of collaborative innovation and cooperation between wireless carriers, IT vendors, networking companies and wireless infrastructure vendors making NFV for LTE possible.”

Global communication service providers, along with many leading vendors, are participating in the European Telecommunications Standards Institute’s (ETSI) Industry Specification Group for Network Functions Virtualization (NFV ISG) to address challenges such as:

• An increasing variety of proprietary hardware appliances like routers, firewalls and switches
• Space and power to accommodate these appliances
• Capital investment challenges
• Short lifespan
• A long procure-design-integrate-deploy lifecycle
• Increasing complexity and diversity of network traffic
• Network capacity limitations

Three main benefits of NFV outlined in the 4G Americas paper include:

• Improved capital efficiency: Provisioning capacity for all functions versus each individual function, providing more granular capacity, exploiting the larger economies of scale associated with Commercial Off-the-Shelf (COTS) hardware, centralizing Virtual Network Functions (VNFs) in data centers where latency requirements allow, and separately and dynamically scaling VNFs residing in the user (or data or forwarding) plane designed for execution in the cloud, control and user-plane functions as needed.
• Operational efficiencies: Deploying VNFs as software using cloud management techniques which enables scalable automation at the click of an operator’s (or customer’s) mouse or in response to stimulus from network analytics. The ability to automate onboarding, provisioning and in-service activation of new virtualized network functions can yield significant savings. 
• Service agility, innovation and differentiation: In deploying these new VNFs, time-to-market for new network services can be significantly reduced, increasing the operator’s ability to capture market share and develop market-differentiating services.

In particular, mobile operators can take advantage of NFV as new services are introduced. Evolved Packet Core (EPC), Voice over LTE (VoLTE), IP Multimedia System (IMS) and enhanced messaging services, among others, are examples of opportunities to use virtualized solutions. Some operators started deploying elements of NFV in 2013 with an expectation that many service areas could be mostly virtualized in the next decade.

The whitepaper as follows:

4G Americas: Bringing Network Function Virtualization to LTE from Zahid Ghadialy

In-flight broadband connectivity service with speeds up to 75Mbps

Came across the following Inmarsat press release:

The new network represents two world-beating achievements for Inmarsat and its partners. It will be the world’s first truly hybrid aviation network, consisting of an S-band satellite (Europasat), constructed by Thales Alenia Space, and a Europe-wide S-band ground network. Over the integrated network, based on state-of-the-art LTE technology and access to sufficient spectrum resources, Inmarsat will be offering airlines the world’s fastest in-flight broadband connectivity service with speeds up to 75Mbps, far in excess of the limited capabilities of North American ATG systems.

Alcatel-Lucent and Inmarsat will work together to develop the ground infrastructure component of the new Europe-wide network. Alcatel-Lucent has proven expertise in the development of 4G LTE-based air-to-ground technology and was the world’s first company to field trial this technology in 2011. The initial contract awarded to Alcatel-Lucent will see the global telecommunications equipment company adapting their existing 4G LTE technology to support the S-band spectrum.

Recently Christophe WILHELM, Senior VP Strategy & Innovation, Thales Alenia Space gave a presentation in the Digiworld Summit 2014.

His presentation is above and the video is as follows. Please forward to 1:36:00 to watch his part

SON Update from 3GPP SA5

Below is a presentation from Christian Toche, 3GPP SA5 chairman in the SON Conference last month. I also blogged about his presentation last year which is available here.

Oct 2014: Update on 3GPP SA5 from 3G4G

Is mobile eating the world?

Another interesting and thought provoking presentation by Ben Evans. His earlier presentation which was very popular as well, is here. The video and slides are embedded below.


How Mobile is Enabling Tech to Outgrow the Tech Industry from Andreessen Horowitz on Vimeo.

And a recent interview by Benedict Evans with Bloomberg TV on the same topic as follows:

New Spectrum Usage Paradigms for 5G

Sometime back I wrote a post that talked about Dynamic Spectrum Access (DSA) techniques for Small Cells and WiFi to work together in a fair way. The Small Cells would be using the ISM bands and Wi-Fi AP's would also be contending for the same spectrum. For those who may not know, this is commonly referred to as LTE-U but the correct term that is being used in standards is LA-LTE, see here for details.

IEEE Comsoc has just published a whitepaper that details how the spectrum should be handled in 5G to make sure of efficient utilisation. The whitepaper covers the following:

Chapter 2 – Introduction, the traditional approach of repurposing spectrum and allocating it to Cellular Wireless systems is reaching its limits, at least below the 6GHz threshold. For this reason, novel approaches are required which are detailed in the sequel of this White Paper.

Chapter 3 - Spectrum Scarcity - an Alternate View provides a generic view on the spectrum scarcity issue and discusses key technologies which may help to alleviate the problem, including Dynamic Spectrum Management, Cognitive Radios, Cognitive Networks, Relaying, etc. 

Chapter 4 – mmWave Communications in 5G addresses a first key solution. While spectrum opportunities are running out at below 6 GHz, an abundance of spectrum is available in mmWave bands and the related technology is becoming mature. This chapter addresses in particular the heterogeneous approach in which legacy wireless systems are operated jointly with mmWave systems which allows to combine the advantages of both technologies. 

Chapter 5 – Dynamic Spectrum Access and Cognitive Radio: A Current Snapshot gives a detailed overview on state-of-the-art dynamic spectrum sharing technology and related standards activities. The approach is indeed complementary to the upper mmWave approach, the idea focuses on identifying unused spectrum in time, space and frequency. This technology is expected to substantially improve the usage efficiency of spectrum, in particular below the 6GHz range. 

Chapter 6 – Licensed Shared Access (LSA) enables coordinated sharing of spectrum for a given time period, a given geographic area and a given spectrum band under a license agreement. In contract to sporadic usage of spectrum on a secondary basis, the LSA approach will guarantee Quality-of-Service levels to both Incumbents and Spectrum Licensees. Also, a clear business model is available through a straightforward license transfer from relevant incumbents to licensees operating a Cellular Wireless network in the concerned frequency bands. 

Chapter 7 – Radio Environment Map details a technology which allows to gather the relevant (radio) context information which feed related decision making engines in the Network Infrastructure and/or Mobile Equipment. Indeed, tools for acquiring context information is critical for next generation Wireless Communication systems, since they are expected to be highly versatile and to constantly adapt. 

Chapter 8 – D2DWRAN: A 5G Network Proposal based on IEEE 802.22 and TVWS discusses the efficient exploitation of TV White Space spectrum bands building on the available IEEE 802.22 standard. TV White Spaces are indeed located in highly appealing spectrum bands below 1 GHz with propagation characteristics that are perfectly suited to the need of Wireless Communication systems. 

Chapter 9 – Conclusion presents some final thoughts. 

The paper is embedded as follows:

Novel Spectrum Usage Paradigms for 5G from Zahid Ghadialy

2015 will finally be the year of Voice over LTE (VoLTE)

On 4th Nov. 2009, the One Voice initiative was published by 12 companies including AT&T, Orange, Telefonica, TeliaSonera, Verizon, Vodafone, Alcatel-Lucent, Ericsson, Nokia Siemens Networks, Nokia, Samsung and Sony Ericsson. These all agreed that the IMS based solution, as defined by 3GPP, is the most applicable approach to meet their consumers expectations for service quality, reliability and availability when moving from existing CS based voice services to IP based LTE services.

On 15th Feb 2010, GSMA announced that it has adopted the work of the One Voice initiative to drive the global mobile industry towards a standard way of delivering voice and messaging services for LTE. The GSMA’s VoLTE initiative was supported by more than 40 organisations from across the mobile ecosystem, including many of the world’s leading mobile communication service providers, handset manufacturers and equipment vendors, all of whom support the principle of a single, IMS-based voice solution for next-generation mobile broadband networks. This announcement was also supported by 3GPP, Next Generation Mobile Networks alliance (NGMN) and the International Multimedia Teleconferencing Consortium (IMTC).

GSMA has produces various reference documents that map to the 3GPP standards documents as can be seen above.

As per GSA: 71 operators are investing in VoLTE studies, trials or deployments, including 11 that have commercially launched HD voice service. The number of HD voice launches enabled by VoLTE is forecast to reach 19 by end-2014 and then double in 2015. In July 2014 GSA confirmed 92 smartphones (including carrier and frequency variants) support VoLTE, including products by Asus, Huawei, LG, Pantech, Samsung and Sony Mobile. The newly-announced Apple iPhone 6 & 6 Plus models support VoLTE.

Things are also moving quickly with many operators who have announced VoLTE launches and are getting more confident day by day. Du, Dubai recently announced Nokia as VoLTE partner. KDDI, Japan is launching au VoLTE in December. Telstra, Australia has already been doing trials and plans to launch VoLTE network in 2015. Finally, Verizon and AT&T will have interoperable VoLTE calls in 2015.

Below is my summary from the LTE Voice Summit 2014. Let me know if you like it.

Quick Summary of LTE Voice Summit 2014 #LTEVoice from eXplanoTech

4G Security and EPC Threats for LTE

This one is from the LTE World Summit 2014. Even though I was not there for this, I think this has some useful information about the 4G/LTE Security. Presentation as follows:

4G Security - Fortinet from Zahid Ghadialy

Codecs and Quality across VoLTE and OTT Networks

Codecs play an important role in our smartphones. Not only are they necessary and must for encoding/decoding the voice packets but they increase the price of our smartphones too.

A $400 smartphone can have as much as $120 in IPR fees. If you notice in the picture above its $10.60 for the H.264 codec. So its important that the new codecs that will come as part of new generation of mobile technology is free, open source or costs very little.

The new standards require a lot of codecs, some for backward compatibility but this can significantly increase the costs. Its important to make sure the new codecs selected are royalty-free or free license.

The focus of this post is a presentation by Amir Zmora from AudioCodecs in the LTE Voice Summit. The presentation below may not be self-explanatory but I have added couple of links at the bottom of the post where he has shared his thoughts. Its worth a read.

Quality Across VoLTE and non-VoLTE Networks from Amir Zmora

A good explanation of Voice enhancement tools as follows (slide 15):

Adaptive Jitter Buffer (AJB) – Almost all devices today (Smartphones, IP phones, gateways, etc.) have built in jitter buffers. Legacy networks (which were LAN focused when designed) usually have older devices with less sophisticated jitter buffers. When designed they didn’t take into account traffic coming in from networks such as Wi-Fi with its frequent retransmissions and 3G with its limited bandwidth, in which the jitter levels are higher than those in wireline networks. Jitter buffers that may have been planned for, say, dozens of msec may now have to deal with peaks of hundreds of msec. Generally, if the SBC has nothing to mediate (assume the codecs are the same and the Ptime is the same on both ends) it just forwards the packets. But the unexpected jitter coming from the wireless network as described above, requires the AJB to take action. And even if the network is well designed to handle jitter, today’s OTT applications via Smart Phones add yet another variable to the equation. There are hundreds of such devices out there, and the audio interfaces of these devices (especially those of the Android phones) create jitter that is passed into the network. For these situations, too, the AJB is necessary.

To overcome this issue, there is a need for a highly advanced Adaptive Jitter Buffer (AJB) built into the SBC that neutralizes the incoming jitter so that it is handled without problem on the other side. The AJB can handle high and variable jitter rates.

Additionally, the AJB needs to work in what is called Tandem scenarios where the incoming and outgoing codec is the same. This scenario requires an efficient solution that will minimize the added delay. AudioCodes has built and patented solutions supporting this scenario.

Transcoding – While the description above discussed the ability to bypass the need to perform transcoding in the Adaptive Jitter Buffer context, there may very well be a need for transcoding between the incoming and outgoing packet streams. Beyond being able to mediate between different codecs on the different networks on either end of the SBC, the SBC can transcode an incoming codec that is less resilient to packet loss (such as narrowband G.729 or wideband G.722) to a more resilient codec (such as Opus). By transcoding to a more resilient codec, the SBC can lower the effects of packet loss. Transcoding can also lower the bandwidth on the network. Additionally, the SBC can transcode from narrowband (8Khz) to wideband (16Khz) (and vice versa) as well as wideband transcoding, where both endpoints support wideband codecs but are not using the same ones. For example, a wireless network may be using the AMR wideband codec while the wireline network on the other side may be using Opus. Had it not been for the SBC, these two networks would have negotiated a common narrowband codec.

Flexible RTP Redundancy – The SBC can also use RTP redundancy in which voice packets are sent several times to ensure they are received. Redundancy is used to balance networks which are characterized by high packet loss burst. While reducing the effect of packet loss, Redundancy increases the bandwidth (and delay). There are ways to get around this bandwidth issue that are supported by the SBC. One way is by sending only partial packet information (not fully redundant packets). The decoder on the receiving side will know how to handle the partial information. This process is called Forward Error Correction (FEC).

Transrating – Transrating is the process of having more voice payload ‘packed’ into a single RTP packet by increasing the packet intervals, thus changing the Packetization Time or Ptime. Ptime is the time represented by the compression of the voice signals into packets, generally at 20 msec intervals. In combining the payloads of two or more packets into one, the Transrating process causes a reduction in the overhead of the IP headers, lowering the bandwidth and reducing the stress on the CPU resources, however, it increases delay. It thus can be used not only to mediate between two end devices using different Ptimes, but also as a means of balancing the network by reducing bandwidth and reducing CPU pressure during traffic peaks.

Quality-based Routing – Another tool used by the SBC is Quality-based routing. The SBC, which is monitoring all the calls on the network all the time, can decide (based on pre-defined thresholds and parameters) to reroute calls over different links that have better quality.

Further reading:

• 3 Things Required for Managing Cross Network Voice Quality
• The Brain behind Voice Quality
• HD Voice - Next step in the evolution of voice communication
• Patent insanity: Royalty fees could reach $120 on a $400 smartphone

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.

What is (pre-5G) 4.5G?

Before we look at what 4.5G is, lets look at what is not 4.5G. First and foremost, Carrier Aggregation is not 4.5G. Its the foundation for real 4G. I keep on showing this picture on Twitter

I am sure some people much be really bored by this picture of mine that I keep showing. LTE, rightly referred to as 3.9G or pre-4G by the South Korean and Japanese operators was the foundation of 'Real' 4G, a.k.a. LTE-Advanced. So who has been referring to LTE-A as 4.5G (and even 5G). Here you go:

Got 4G? Wake up, grandad. We're doing 4.5G LTE-A in London - EE chief: And get a load of our gleaming voice system! … http://t.co/78HSHlyPuA
— The Register (@TheRegister) March 5, 2014

Voda UK PR says: "The new technology, called Carrier Aggregation but also referred to as LTE Advanced or 4.5G" 4.5G?
— Keith Dyer (@keithdyer) October 15, 2014

5G wireless technology LTE-Advanced is now running in the Philippines' largest and strongest network. | http://t.co/g8u3lJ8sLV #Smart5G
— Smart Communications (@SMARTCares) August 14, 2014

So lets look at what 4.5G is.

Back in June, we published a whitepaper where we referred to 4.5G as LTE and WiFi working together. When we refer to LTE, it refers to LTE-A as well. The standards in Release-12 allow simultaneous use of LTE(-A) and WiFi with selected streams on WiFi and others on cellular.

Some people dont realise how much spectrum is available as part of 5GHz, hopefully the above picture will give an idea. This is exactly what has tempted the cellular community to come up with LTE-U (a.k.a LA-LTE, LAA)

In a recent event in London called 5G Huddle, Alcatel-Lucent presented their views on what 4.5G would mean. If you look at the slide above, it is quite a detailed view of what this intermediate step before 5G would be. Some tweets related to this discussion from 5G Huddle as follows:

Good points: 4.5G as necessary step: CA, VoLTE & WebRTC, CoMP & coordination, NFV & cloud. But that can do everything we need #5GHuddle
— Real Wireless (@real_wireless) September 23, 2014

So 5G will be evolution of 4.5G using DC & CA - but much better signalling, more energy efficient as new air interface for IoT
— Real Wireless (@real_wireless) September 23, 2014

Finally, in a recent GSMA event, Huawei used the term 4.5G to set out their vision and also propose a time-frame as follows:

While in Alcatel-Lucent slide, I could visualise 4.5G as our vision of LTE(-A) + WiFi + some more stuff, I am finding it difficult to visualise all the changes being proposed by Huawei. How are we going to see the peak rate of 10Gbps for example?

I have to mention that I have had companies that have told me that their vision of 5G is M2M and D2D so Huawei is is not very far from reality here.

We should keep in mind that this 4G, 4.5G and 5G are the terms we use to make the end users aware of what new cellular technology could do for them. Most of these people understand simple terms like speeds and latency. We may want to be careful what we tell them as we do not want to make things confusing, complicated and make false promises and not deliver on them.

xoxoxo Added on 2nd January 2015 oxoxox

Chinese vendor ZTE has said it plans to launch a ‘pre-5G’ testing base station in 2015, commercial use of which will be possible in 2016, following tests and adjustment. Here is what they think pre-5G means:

'Real' Full Duplex (or No Division Duplex - NDD?)

We all know about the two type of transmission schemes which are FDD and TDD. Normally, this FDD and TDD schemes are known as full duplex schemes. Some people will argue that TDD is actually half-duplex but what TDD does is that it emulates a full duplex communication over a half duplex communication link. There is also a half-duplex FDD, which is a very interesting technology and defined for LTE, but not used. See here for details.

One of the technologies being proposed for 5G is referred to as Full Duplex. Here, the transmitter and the receiver both transmit and receive at the same frequency. Due to some very clever signal processing, the interference can be cancelled out. An interesting presentation from Kumu networks is embedded below:

Full Duplex Radios in 5G from Zahid Ghadialy

The biggest challenge is self-interference cancellation because the transmitter and receiver are using the same spectrum and will cause interference to each other. There have been major advances in the self-interference cancellation techniques which could be seen in the Interdigital presentation embedded below:

Potential of Full Duplex for Future Wireless Systems from Zahid Ghadialy

A quick update on Antennas

There were couple of very interesting and useful presentations from the LTE World Summit 2014 that I have been thinking for a while to embed in the blog. The first is a market overview from Signals Research Group. The research is focussed more on the US market but it has some very interesting insights. The slideset is embedded below:

Antenna Market Overview - Signals Research Group - June 2014 from Zahid Ghadialy

The other presentation is from Commscope on Base Station Antennas (BSA) for capacity improvement. I really liked the simplicity of the diagrams. Anyone interested in studying more indepth on the antennas are encouraged to check out my old post here. The complete slideset is below:

Commscope: Antennas Solutions for Capacity Improvement - June 2014 from Zahid Ghadialy

Envelope Tracking for improving PA efficiency of mobile devices

I am sure many people would have heard of ET (Envelope Tracking) by now. Its a technology that can help reduce the power consumption by our mobile devices. Less power consumption means longer battery life, especially with all these new features coming in the LTE-A devices.

As the slide says, there are already 12 phones launched with this technology, the most high profile being iPhone 6/6 Plus. Here is a brilliant presentation from Nujira on this topic:

Envelope Tracking : Fuel injection for the RF Front End from Zahid Ghadialy

For people who are interested in testing this feature may want to check this Rohde&Schwarz presentation here.

Elevation Beamforming / Full-Dimension MIMO

Four major Release-13 projects have been approved now that Release-12 is coming to a conclusion. One of them is Full dimension MIMO. From the 3GPP website:

Leveraging the work on 3D channel modeling completed in Release 12, 3GPP RAN will now study the necessary changes to enable elevation beamforming and high-order MIMO systems. Beamforming and MIMO have been identified as key technologies to address the future capacity demand. But so far 3GPP specified support for these features mostly considers one-dimensional antenna arrays that exploit the azimuth dimension. So, to further improve LTE spectral efficiency it is quite natural to now study two-dimensional antenna arrays that can also exploit the vertical dimension.

Also, while the standard currently supports MIMO systems with up to 8 antenna ports, the new study will look into high-order MIMO systems with up to 64 antenna ports at the eNB, to become more relevant with the use of higher frequencies in the future.

Details of the Study Item can be found in RP-141644.

There was also an interesting post by Eiko Seidel in the 5G standards group:

The idea is to introduce carrier and UE specific tilt/beam forming with variable beam widths. Improved link budget and reduced intra- and inter-cell interference might translate into higher data rates or increased coverage at cell edge. This might go hand in hand with an extensive use of spatial multiplexing that might require enhancements to today’s MU-MIMO schemes. Furthermore in active antenna array systems (AAS) the power amplifiers become part of the antenna further improving the link budget due to the missing feeder loss. Besides a potentially simplified installation the use of many low power elements might also reduce the overall power consumption. 

At higher frequencies the antenna elements can miniaturized and their number can be increased. In LTE this might be limited to 16, 32 or 64 elements while for 5G with higher frequency bands this might allow for “massive MIMO”. 

WG: Primary RAN1 (RP-141644) 
started 06/2014 (RAN#64), completion date 06/2015 (RAN#68)
work item might follow the study with target 12/2015 (RAN#70) 

Supporting companies
Samsung/NSN, all major vendors and operators 

Based on RAN1 Rel.12 Study Item on 3D channel model (TR36.873) 

Objectives 
Phase 1: antenna configurations and evaluation scenarios Rel.12 performance evaluation with 3D channel model 

Phase 2: study and simulate FD-MIMO enhancement identify and evaluate techniques, analyze specification impact performance evaluation for 16, 32, 64 antenna elements enhancements for SU-/MU-MIMO (incl. higher dimension MU-MIMO) (keep the maximum number of layer per UE unchanged to 8)

An old presentation from Samsung is embedded below that will provide more insight into this technology:

Full Dimension MIMO and Beamforming Technologies for B4G from Zahid Ghadialy

Related post:

• 3D-Beamforming and 3D-MIMO

NFV and 5G compatibility issues

There was an interesting discussion on Twitter that has been storified by Keith Dyer. Lets start by having a quick look at the C-RAN architecture that features in the discussion.

There are couple of excellent C-RAN presentations for anyone interested. This one by EE (with 9K+ views) and this from Orange (with 19K+ views).

Anyway, here is the story:

For anyone interested in exploring the discussion further, The Mobile Network has a more detailed comments here.

There are also an interesting article worth reading:

• Clouding the Edge for LTE-A and Beyond
• 5G Will Give Operators Massive Headaches – Bell Labs

Update on Public Safety and Mission Critical communications

Its been a while since I wrote about Public Safety and Mission Critical communications, so here is a quick summary.

Iain Sharp have a good overview of whats happening in the standards in the LTE World Summit back in June. Embedded below is his complete presentation.

LTE Standards for Public Safety – an independent analysis from Zahid Ghadialy

There is another slightly older presentation that I also thought was worthwhile adding here.

There is a lot of discussion centred around the use of commercial networks for mission critical communications, mainly die to cost. While this may make sense to an extent, there should be procedures put in place to give priority to public safety in case of emergency.

Tech Trend for Next Generation Critical Communications from Zahid Ghadialy

We are planning to run a one day training in Jan 2015 on public safety. If this is of interest to you then please get in touch with me for more details.

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After the post someone brought these links to my attention so I am adding them below:

• Mission-Critical PTT Set for LTE Release 13, Release 12 Freeze Likely in 2015
• 3GPP News: LTE Mission Critical Applications
• 3GPP News: Delivering Public Safety Communications with LTE
• 3GPP SA6 - Mission-critical applications
• 3GPP-OMA-ETSI Critical Communications Workshop, August 26-27, 2014

LTE Device-to-device (D2D) Use Cases

Device-to-device is a popular topic. I wrote a post, back in March on LTE-Radar (another name) which has already had 10K+ views. Another post in Jan, last year has had over 13K views. In the LTE World Summit, Thomas Henze from Deutsche Telekom AG presented some use cases of 'proximity services via LTE device broadcast'

While there are some interesting use cases in his presentation (embedded below), I am not sure that they will necessarily achieve success overnight. While it would be great to have a standardised solution for applications that rely on proximity services, the apps have already come up with their own solutions in the meantime.



The dating app Tinder, for example, finds a date near where you are. It relies on GPS and I agree that some people would say that GPS consumes more power but its already available today.



Another example is "Nearby Friends" from Facebook that allows to find your friends if they are nearby, perfect for a day when you have nothing better to do.

With an App, I can be sure that my location is being shared only for one App. With a standardised solution, all my Apps have info about location that I may not necessarily want. There are pros and cons, not sure which will win here.

Anyway, the complete presentation is embedded below:

Enabling proximity services via LTE device broadcast from Zahid Ghadialy

For anyone interested in going a bit more in detail about D2D, please check this excellent article by Dr. Alastair Bryon, titled "Opportunities and threats from LTE Device-to-Device (D2D) communication"

Do let me know what you think about the use cases.