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Articles on this Page
- 10/11/14--11:02: _A quick update on A...
- 10/14/14--12:15: _'Real' Full Duplex ...
- 10/19/14--09:45: _What is (pre-5G) 4.5G?
- 10/23/14--10:39: _Detailed whitepaper...
- 10/30/14--02:33: _Codecs and Quality ...
- 11/01/14--10:50: _4G Security and EPC...
- 11/05/14--03:09: _2015 will finally b...
- 11/11/14--12:27: _New Spectrum Usage ...
- 11/16/14--11:24: _Is mobile eating th...
- 11/18/14--01:57: _SON Update from 3GP...
- 11/21/14--10:18: _In-flight broadband...
- 12/01/14--05:00: _Bringing Network Fu...
- 12/12/14--03:00: _5G Spectrum and cha...
- 12/23/14--03:13: _M2M embedded UICC (...
- 12/29/14--01:29: _The SS7 flaws that ...
- 12/30/14--09:00: _Top 10 posts for 2014
- 01/07/15--03:14: _Enhancing voice ser...
- 01/14/15--06:57: _IEEE Globecom 2014 ...
- 01/21/15--14:02: _Voice over WiFi (Vo...
- 02/03/15--13:16: _5G: A 2020 Vision
- 10/11/14--11:02: A quick update on Antennas
- 10/14/14--12:15: 'Real' Full Duplex (or No Division Duplex - NDD?)
- 10/19/14--09:45: What is (pre-5G) 4.5G?
- 10/23/14--10:39: Detailed whitepaper on Carrier Aggregation by 4G Americas
- 10/30/14--02:33: Codecs and Quality across VoLTE and OTT Networks
- 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
- 11/01/14--10:50: 4G Security and EPC Threats for LTE
- 11/05/14--03:09: 2015 will finally be the year of Voice over LTE (VoLTE)
- 11/11/14--12:27: New Spectrum Usage Paradigms for 5G
- 11/16/14--11:24: Is mobile eating the world?
- 11/18/14--01:57: SON Update from 3GPP SA5
- 11/21/14--10:18: In-flight broadband connectivity service with speeds up to 75Mbps
- 12/01/14--05:00: Bringing Network Function Virtualization (NFV) to LTE
- 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
- 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.
- 12/12/14--03:00: 5G Spectrum and challenges
- IEEE ComSoc: 5G Wireless Demos Use High Frequencies
- HUAWEI, TELE2 disagree on role of spectrum for 5G
- 12/23/14--03:13: M2M embedded UICC (eSIM) Architecture and Use Cases
- 12/29/14--01:29: The SS7 flaws that allows hackers to snoop on your calls and SMS
- 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
- 12/30/14--09:00: Top 10 posts for 2014
Different flavours of SRVCC (Single Radio Voice Call Continuity) - January 2014
MNO, MVNO, MVNA, MVNE - The different types of operators - April 2014
New LTE-A UE Category 9 and 10 in Rel-11 - August 2014
4.5G: Integration of LTE and Wi-Fi networks - June 2014
Voice over WiFi (VoWiFi) - June 2014
Further enhanced Inter-Cell Interference Coordination (FeICIC) - May 2014
VoLTE Roaming with RAVEL (Roaming Architecture for Voice over IMS with Local Breakout) - February 2014
What is (pre-5G) 4.5G? - October 2014
LA-LTE and LAA - July 2014
- Multi-SIM: The Jargon - January 2014
- 01/07/15--03:14: Enhancing voice services using VoLTE
- DOCOMO VoLTE and Next Steps
- VoLTE Roaming with RAVEL (Roaming Architecture for Voice over IMS with Local Breakout)
- 2015 will finally be the year of Voice over LTE (VoLTE)
- 01/21/15--14:02: Voice over WiFi (VoWiFi) technical details
- 02/03/15--13:16: 5G: A 2020 Vision
here. The complete slideset is below:
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:
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.
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)
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 IoTFinally, in a recent GSMA event, Huawei used the term 4.5G to set out their vision and also propose a time-frame as follows:
— Real Wireless (@real_wireless) September 23, 2014
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.
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
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.
You can read more about the 4G Americas whitepaper in their press release here.
$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.
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.
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).
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.
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:
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:
Came across the following Inmarsat press release:
His presentation is above and the video is as follows. Please forward to 1:36:00 to watch his part
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 whitepaper as follows:
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.
xoxoxo Added Later (13/12/2014) xoxoxo
Here are some links on the related topic:
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:
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:
Here are the top 10 posts of 2014 from The 3G4G Blog:
VoLTE has been a very popular topic on this blog. My overview of the LTE Voice Summit missed out narrowly from the Top 10 posts of 2014 but there were other posts related to VoLTE that made it.
In this magazine article, NTT Docomo not only talks about its own architecture and transition from 3G to 4G for voice and video, it provides some detailed insights from its own experience.
The paper is embedded below and available from slideshare to download.
Embedded below is a video from the keynote session by Dr. Wen Tong of Huawei. I do not have the latest presentation but an earlier one (6 months old) is also embedded below for reference. It will give you a good idea on the 5G research direction
You may also be interested in this other presentation from Huawei in IEEE Globecom 2014, 5G: From Research to Standardization (what, how, when)
Anybody reading this post is not aware of S2a, S2b, Samog, TWAG, ePDG, etc. and what they are, please refer to our whitepaper on cellular and wi-fi integration here (section 3).
There are two approaches to VoWiFi, native client already in your device or an App that could be either downloaded from the app store or pre-installed. The UK operator '3' has an app known as ThreeInTouch. While on WiFi, this app can make and receive calls and texts. The only problem is that it does not handover an ongoing call from WiFi to cellular and and vice versa. Here are a few slides (slides 36-38) from them from a conference last year:
The other operators have a native client that can use Wi-Fi as the access network for voice calls as well as the data when the device is connected on the WLAN.
Now, I dont want to talk about VoLTE bearers establishment, etc. which I have already done here earlier. In order to establish S2a (trusted) and S2b (untrusted) connection, the AAA server selects an APN among those which are subscribed to in the HLR/HSS. The PDN-GW (generally referred to as PGW) dynamically assigns an IP address out of a pool of addresses which is associated with this APN. This UE IP address is used by the VoWiFi SIP UA (User Agent) as the contact information when registering to the SIP soft switch (which would typically be the operators IMS network).
If for any reason the SIP UA in the device is not able to use the SIM for authentication (needs ISIM?) then a username/password based authentication credentials can be used (SIP digest authentication).
Typically, there would be a seperate UA for VoLTE and VoWiFi. They would both be generally registering to the same IMS APN using different credentials and contact addresses. The IMS network can deal with multiple registrations from the same subscriber but from different IP addresses (see 3GPP TS 23.237 - 'IMS Service Continuity' for details).
Because of multiple UA's, a new element needs to be introduced in order to 'fork' the downstream media streams (RTP/RTCP packets) to different IP addresses over time.
3GPP has defined the Access Transfer Gateway (ATGW) which is controlled by the Access Transfer Control Function (ATCF); the ATCF interfaces to the IMS and Service Centralization and Continuity Application Server (SCC AS). All these are not shown in the picture above but is available in 3GPP TS 23.237. The IMS networks in use today as well as the one being deployed for VoLTE does not have ATGW/ATCF. As a result vendors have to come up with clever non-standardised solutions to solve the problem.
When there is a handover between 3GPP and non-3GPP networks, the UE IP address needs to be preserved. Solutions like MIP and IPSec have been used in the past but they are not flexible. The Release-12 solution of eSAMOG (see 3GPP TS 23.402) can be used but the solution requires changes in the UE. For the time being we will see proprietary solutions only but hopefully in future there would be standardised solutions available.
3GPP TS 23.234 describes more in detail the interworking of 3GPP based system and WLAN. Interested readers can refer to that for further insight.
I had the pleasure of speaking at the CW (Cambridge Wireless) event ‘5G: A Practical Approach’. It was a very interesting event with great speakers. Over the next few weeks, I will hopefully add the presentations from some of the other speakers too.
In fact before the presentation (below), I had a few discussions over the twitter to validate if people agree with my assumptions. For those who use twitter, maybe you may want to have a look at some of these below:
5G is coming, maybe much earlier than you expect it to. There is a race to be first. Come... http://t.co/BQUR5p3bpkpic.twitter.com/z3cOD7Xv2O
— eXplanoTech (@eXplanoTech) January 30, 2015
@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
Spectrum Bands Summary - Can anyone point me to a better picture? (Cc @open_spectrum@StevenJCrowley@elenaneira) pic.twitter.com/IkBhtQubSj
— Zahid Ghadialy (@zahidtg) January 19, 2015
Anyway, here is the presentation.