Showing posts with label (e)MBMS. Show all posts
Showing posts with label (e)MBMS. Show all posts

Tuesday, 19 May 2020

5G Dynamic Spectrum Sharing (DSS)

5G Dynamic Spectrum Sharing is a hot topic. I have already been asked about multiple people for links on good resources / whitepapers. So here is what we liked, feel free to add anything else you found useful as part of comments.


Nokia has a nice high level overview of this topic which is available here. I really liked the decision tree as shown in the tweet above. I am going to quote a section here that is a great summary to decide if you want to dive deeper.

DSS in the physical layer
DSS allows CSPs to share resources dynamically between 4G and 5G in time and/or frequency domains, as shown on the left of Figure 3. It’s a simple idea in principle, but we also need to consider the detailed structure at the level of the resource block in order to understand the resource allocations for the control channels and reference signals. A single resource block is shown on the right side of Figure 3.

The 5G physical layer is designed to be so similar to 4G in 3GPP that DSS becomes feasible with the same subcarrier spacing and similar time domain structure. DSS is designed to be backwards compatible with all existing LTE devices. CSPs therefore need to maintain LTE cell reference signal (CRS) transmission. 5G transmission is designed around LTE CRS in an approach called CRS rate matching.

5G uses demodulation reference signals (DMRS), which are only transmitted together with 5G data and so minimize any impact on LTE capacity. If all LTE devices support Transmission Mode 9 (TM9), then the shared carrier has lower overheads because less CRS transmission is required. The control channel transmission and the data transmission can be selected dynamically between LTE and 5G, depending on the instantaneous capacity requirements.


The second resource is this Rohde & Schwarz webinar here. As can be seen in the tweet above, it provides nice detailed explanation.

Finally, we have a Comprehensive Deployment Guide to Dynamic Spectrum Sharing for 5G NR and 4G LTE Coexistence, which is a nice and detailed whitepaper from Mediatek. Quoting a small section from the WP for anyone not wanting to go too much in deep:

The DSS concept is based on the flexible design of NR physical layer. It uses the idea that NR signals are transmitted over unused LTE resources. With LTE, all the channels are statically assigned in the time-frequency domain, whereas the NR physical layer is extremely flexible for reference signals, data and control channels, thus allowing dynamic configurations that will minimize a chance of collision between the two technologies. 

One of the main concepts of DSS is that only 5G users are made aware of it, while the functionalities of the existing LTE devices remain unaffected (i.e. LTE protocols in connected or idle mode). Therefore, fitting the flexible physical layer design of NR around that of LTE is needed in order to deploy DSS on a shared spectrum. This paper discusses the various options of DSS implementation, including deployment challenges, possible impacts to data rates, and areas of possible improvements.

NR offers a scalable and flexible physical layer design depicted by various numerologies. There are different subcarrier spacing (SCS) for data channels and synchronization channels based on the band assigned. This flexibility brings even more complexity because it overlays the NR signals over LTE, which requires very tight coordination between gNB and eNB in order to provide reliable synchronization in radio scheduling.

The main foundation of DSS is to schedule NR users in the LTE subframes while ensuring no respective impact on LTE users in terms of essential channels, such as reference signals used for synchronization and downlink measurements. LTE Cell Reference Signals (CRS) is typically the main concept where DSS options are designated, as CRS have a fixed time-frequency resource assignment. The CRS resources layout can vary depending on the number of antenna ports. More CRS antenna ports leads to increased usage of Resource Elements (REs). CRS generates from 4.76% (1 antenna port) up to 14.29% (4 antenna ports) overhead in LTE resources. As CRS is the channel used for downlink measurements, avoiding possible collision with CRS is one of the foundations of the DSS options shown in figure 1. The other aspect of DSS design is to fit the 5G NR reference signals within the subframes in a way to avoid affecting NR downlink measurements and synchronization. For that, DSS considers the options shown in figure 1 to ensure NR reference signals such as Synchronization Signal Block (SSB) or Demodulation Reference Signal (DMRS) are placed in time-frequencies away from any collision with LTE signals.

MBSFN, option 1 in figure 1, stands for Multi-Broadcast Single-Frequency Network and is used in LTE for point-to-multipoint transmission such as eMBMS (Evolved Multimedia Broadcast Multicast Services). The general idea of MBSFN is that specific subframes within an LTE frame reserve the last 12 OFDM symbols of such subframe to be free from other LTE channel transmission. These symbols were originally intended to be used for broadcast services and are “muted” for data transmission in other LTE UE. Now this idea has been adjusted for use in a DSS concept, so that these reserved symbols are used for NR signals instead of eMBMS. While in general LTE PDCCH can occupy from 1 to 3 symbols (based on cell load), the first two OFDM symbols of such MBSFN subframe are used for LTE PDCCH, and DSS NR UE can use the third symbol. Using MBSFN is completely transparent to legacy LTE-only devices from 3GPP Release 9 onwards, as such LTE UE knows that these subframes are used for other purposes. In this sense this is the simplest way of deploying DSS. This method has disadvantages though. The main one is that if MBSFN subframes are used very frequently and it takes away resources from LTE users, heavily reducing LTE-only user throughput. Note that option 1 shown in figure 1 does not require LTE MBSFN Reference Signals to be used, because the MBSFN subframe is used to mute the subframe for DSS operation only, and LTE CRS shall only be transmitted in the non-MBSFN region (within the first two symbols) of the MBSFN subframe.

The two other options illustrated in figure 1 are dealing with non-MBSFN subframes that contain LTE reference signals. Option 2 is ‘mini-slot’ based; mini-slot scheduling is available in NR for URLLC applications that require extremely low latency. The symbols can be placed anywhere inside the NR slot. In respect to DSS, mini-slot operation just eliminates the usage of the symbols that contain LTE CRS and schedule only free ones for NR transmission. The basic limitation of this method comes from the concept itself. It is not very suitable for eMBB applications as too many resources are outside of NR scheduling. However it still can be utilized in some special cases like 30 kHz SSB insertion which will be described later in this paper.

Option 3 is based on CRS rate matching in non-MBSFN subframes, and it is expected to be the one most commonly used for NR data channels. In this option, the UE performs puncturing of REs used by LTE CRS so that the NR scheduler knows which REs are not available for NR data scheduling on PDSCH (Physical Downlink Shared Channel). The implementation of this option can be either Resource Block (RB)-level when the whole RB containing LTE CRS is taken out of NR scheduling, or RE-level where NR PDSCH scheduling avoids particular REs only. The end result of this method is that the scheduler will reduce the NR PDSCH transport block size as the number of REs available for scheduling become less in a slot.


Personally, I am not a big fan of DSS mainly because I think it is only useful in a very few scenarios. Also, it helps operators show a 5G logo but doesn't provide a 5G experience by itself. Nevertheless, it can come in handy for the coverage layer of 5G.


In one of the LinkedIn discussions (that I try and avoid mostly) somebody shared this above picture of Keysight Nemo DSS lab test results. As you can see there is quite a bit of overhead with DSS.

Sunday, 27 October 2019

R&S Webinar on LTE-A Pro and evolution to 5G


Rohde & Schwarz recently uploaded a webinar video on their YouTube channel. I found it really useful. It's embedded below.

Topics covered:

  • LTE-M / NB-IoT
    • feMTC
    • UE Category M2
    • OTDOA based positioning
  • UE Categories
  • Unlicensed Spectrum Overview
  • LTE in Unlicensed Spectrum
    • LWA, LWIP
    • LAA, eLAA
    • Wi-Fi
    • LBT
    • LWA mobility
  • Carrier Aggregation Enhancements
  • Multi-user superposition transmission (MUST)
  • Single cell - point to multipoint transmission (SC-PTM)
    • SC-PTM Channel Structure
    • SC-PTM Channel Flow
  • Massive MIMO
  • V2X Overview
    • eNB scheduling - transmission mode 3
    • Distributed scheduling - transmission mode 4
    • Direct communication
  • LTE Advanced Pro (Release 15)
    • Further NB-IoT Enhancements
    • Even further enhanced MTC - eMTC4 (Rel-15)



Related Posts:

Thursday, 29 August 2019

LTE / 5G Broadcast Evolution


It's been a while since I last wrote about eMBMS. A report by GSA last month identified:
- 41 operators known to have been investing in eMBMS
- 5 operators have now deployed eMBMS or launched some sort of commercial service using eMBMS
- GSA identified 69 chipsets supporting eMBMS, and at least 59 devices that support eMBMS


BBC R&D are testing the use of 4G/5G broadcast technology to deliver live radio services to members of the public as part of 5G RuralFirst - one of 6 projects funded under the UK Government’s 5G Phase 1 testbeds and trials programme (link).

A press release by Samsung Electronics back in May announced that it has signed an expansion contract with KT Corporation (KT) to provide public safety (PS-LTE) network solutions based on 3GPP standard Release 13 for 10 major metropolitan regions in South Korea including Seoul by 2020. One of the features of PS-LTE that the PR listed was LTE Broadcast (eMBMS): A feature which allows real time feeds to hundreds of devices simultaneously. It enables thousands of devices to be connected at once to transfer video, images and voice simultaneously using multicast technology

Dr. Belkacem Mouhouche – Samsung Electronics Chief Standards Engineer  and Technical Manager of 5G projects: 5G-Xcast and 5G-Tours Presented an excellent overview on this topic at IEEE 5G Summit Istanbul, June 2019. His presentation is embedded below.



5G-Xcast is a 5GPPP Phase II project focused on Broadcast and Multicast Communication Enablers For the Fifth Generation of Wireless Systems.

They have a YouTube channel here and this video below is an introduction to project and the problems it looks to address.




Further Reading:

Related posts:

Tuesday, 24 July 2018

Multicast Operation on Demand (MooD) and Service Continuity for eMBMS


Many regular readers of this blog are aware that back in 2014 I wrote a post looking critically at LTE-Broadcast business case and suggested a few approaches to make it a success. Back in those days, 2014 was being billed as the year of LTE-Broadcast or eMBMS (see here and here for example). I was just cautioning people against jumping on the LTE-B bandwagon.

According to a recent GSA report 'LTE Broadcast (eMBMS) Market Update – March 2018':

  • thirty-nine operators are known to have been investing in eMBMS demonstrations, trials, deployments or launches
  • five operators have now deployed eMBMS or launched some sort of commercial service using eMBMS

Its good to see some operators now getting ready to deploy eMBMS for broadcast TV scenarios. eMBMS will also be used in Mission Critical Communications for the features described here.

In a recent news from the Australian operator Telstra:

Telstra is now streaming live sports content to a massive base of around 1.2 million devices each weekend and sports fans consume 37 million minutes of live content over our apps on any given weekend.

This increase brings new challenges to the way traffic on our mobile network is managed. Even though a large group of people might be streaming the same real-time content at the same time, we still need to ensure a high quality streaming experience for our customers.

This challenge makes our sporting apps a prime use case for LTE-Broadcast (LTE-B).

Earlier this year, we announced we would be turning on LTE-B functionality on the AFL Live Official app for Telstra customers with Samsung Galaxy S8 and Galaxy S9 devices. Following extensive testing, Telstra is the only operator in Australia – and one of the first in the world – to deploy LTE-B into its mobile network.

At a live demonstration in Sydney, over 100 Samsung Galaxy S8 and Galaxy S9 devices were on display showing simultaneous high definition content from the AFL Live Official app using LTE-B.

Its interesting to note here that the broadcast functionality (and probably intelligence) is built into the app.

According to another Telstra news item (emphasis mine):

The use of LTE-Broadcast technology changes the underlying efficiency of live video delivery as each cell can now support an unlimited number of users watching the same content with improved overall quality. To date though, LTE-B technology has required that a dedicated part of each cell’s capacity be set aside for broadcasting. This had made the LTE-B business case harder to prove in for lower streaming demand rates.

This has now changed as Telstra and our partners have enabled the world’s first implementation of the Multicast Operation on Demand (MooD) feature whereby cells in the network only need to configure for LTE-B when there are multiple users watching the same content.

This combined with the Service Continuity feature allows mobile users to move around the network seamlessly between cells configured for LTE-B and those which are not.

Earlier this year we announced our intention to enable LTE-Broadcast (LTE-B) across our entire mobile network in 2018. With MooD and service continuity we are one step closer to that goal as we head into another year of major growth in sporting content demand.

Supported by technology partners Ericsson and Qualcomm, Telstra has now delivered world first capability to ensure LTE-B can be delivered as efficiently as possible.

Service Continuity will allow devices to transition in and out of LTE-B coverage areas without interruption. For instance, you might be at a music festival streaming an event on your phone but need to leave the venue and make your way back home (where LTE-B is not in use). Service Continuity means you can continue to watch the stream and the transition will be seamless – even though you have the left the broadcast area.

Taking that a step further, MooD allows the network to determine how many LTE-B compatible devices in any given area are consuming the same content. MooD then intelligently activates or deactivates LTE-B, ensuring the mobile network is as efficient as possible in that location.

For example, if a die-hard football fan is streaming a match we will likely service that one user with unicast, as that is the most efficient way of delivering the content. However if more users in the same cell decide to watch the match, MooD makes the decision automatically as to whether it is more efficient to service those users by switching the stream to broadcasting instead of individual unicast streams.

Its good to see Ericsson & Qualcomm finally taking eMBMS to commercial deployment. Back in 2015, I added their videos from MWC that year. See post here.
I think the Telstra post already provides info on why MooD is needed but this picture from Qualcomm whitepaper above makes it much clearer. Back in 3G MBMS and early days or eMBMS, there used to be a feature called counting, MooD is effectively doing the same thing.
For Service Continuity, this paper 'Service Continuity for eMBMS in LTE/LTE-Advanced Network: Standard Analysis and Supplement' by Ngoc-Duy Nguyen and Christian Bonnet has interesting proposal on how it should be done. I cannot be sure if this is correct as per the latest specifications but its interesting to learn how this would be done when the user moves out of coverage area in Idle or connected mode.

Note that this Expway paper also refers to Service continuity as Session continuity.

Related posts:



Tuesday, 5 December 2017

Summary of 3GPP Release-14 Work Items


With all focus on 5G (Release-15), looks like Rel-14 has been feeling a bit neglected. There are some important updates though as it lays foundation for other services.

3GPP used to maintain Release Descriptions here for all different releases but have stopped doing that since 2014. For Release-14, a new document "3GPP TR 21.914: Release 14 Description; Summary of Rel-14 Work Items" is now available here.

An executive summary from the document:

Release 14 focusses on the following items:
  • Improving the Mission Critical aspects, in particular with the introduction of Video and Data services
  • Introducing the Vehicle-to-Everything (V2X) aspects, in particular the Vehicle-to-Vehicle (V2)
  • Improving the Cellular Internet of Things (CIoT) aspects, with 2G, 3G and 4G support of Machine-Type of Communications (MTC)
  • Improving the radio interface, in particular by enhancing the aspects related to coordination with WLAN and unlicensed spectrum
  • A set of uncorrelated improvements, e.g. on Voice over LTE (VoLTE), IMS, Location reporting.


The continuation of this document provides an exhaustive view of all the items specified by 3GPP in Release 14.

I have blogged about the Mission Critical Communications here. 3GPP has also done a webinar on this topic which can be viewed here. I like this slide below that summarizes features in different releases.

Then there are quite a few new features and enhancements for V2X. I have blogged about sidelink and its proposed extensions here.

From the document:

The Work Item on “Architecture enhancements for LTE support of V2X services (V2XARC)”, driven by SA WG2, specifies the V2X architectures, functional entities involved for V2X communication, interfaces, provisioned parameters and procedures in TS 23.285.
Figure above depicts an overall architecture for V2X communication. V2X Control Function is the logical function defined for network related actions required for V2X and performs authorization and provisioning of necessary parameters for V2X communication to the UE via V3 interface.

A UE can send V2X messages over PC5 interface by using network scheduled operation mode (i.e. centralized scheduling) and UE autonomous resources selection mode (i.e. distributed scheduling) when the UE is "served by E-UTRAN" while a UE can send V2X messages over PC5 interface only by using UE autonomous resources selection mode when the UE is "not served by E-UTRAN". 

Both IP based and non-IP based V2X messages over PC5 are supported. For IP based V2X messages over PC5, only IPv6 is used. PPPP (ProSe Per-Packet Priority) reflecting priority and latency for V2X message is applied to schedule the transmission of V2X message over PC5.

A UE can send V2X messages over LTE-Uu interface destined to a locally relevant V2X Application Server, and the V2X Application Server delivers the V2X messages to the UE(s) in a target area using unicast delivery and/or MBMS (Multimedia Broadcast/Multicast Service) delivery.

Both IP based and non-IP based V2X messages are supported for V2X communication over LTE-Uu. In order to transmit non-IP based V2X messages over LTE-Uu, the UE encapsulates the V2X messages in IP packets.

For latency improvements for MBMS, localized MBMS can be considered for localized routing of V2X messages destined to UEs.

For V2X communication over LTE-Uu interface, the V2X messages can be delivered via Non-GBR bearer (i.e. an IP transmission path with no reserved bitrate resources) as well as GBR bearer (i.e. an IP transmission path with reserved (guaranteed) bitrate resources). In order to meet the latency requirement for V2X message delivery, the following standardized QCI (QoS Class Identifier) values defined in TS 23.203 can be used:
  • QCI 3 (GBR bearer) and QCI 79 (Non-GBR bearer) can be used for the unicast delivery of V2X messages.
  • QCI 75 (GBR bearer) is only used for the delivery of V2X messages over MBMS bearers. 


There are updates to cellular IoT (CIot) which I have blogged about here.

There are some other interesting topic that are enhanced as part of Release14. Here are some of them:
  • S8 Home Routing Architecture for VoLTE
    • Robust Call Setup for VoLTE subscriber in LTE
    • Enhancements to Domain Selection between VoLTE and CDMA CS
    • MBMS improvements
    • eMBMS enhancements for LTE
    • IMS related items
    • Evolution to and Interworking with eCall in IMS
    • Password-based service activation for IMS Multimedia Telephony service
    • Multimedia Priority Service Modifications
    • Enhancements to Multi-stream Multiparty Conferencing Media Handling
    • Enhancement for TV service
    • Improved Streaming QoE Reporting in 3GPP (IQoE)
    • Quality of Experience (QoE) Measurement Collection for streaming services in UTRAN
    • Development of super-wideband and fullband P.835
    • Enhancements to User Location Reporting Support
    • Enhancing Location Capabilities for Indoor and Outdoor Emergency Communications
    • Further Indoor Positioning Enhancements for UTRA and LTE
    • Improvements of awareness of user location change
    • Terminating Access Domain Selection (T-ADS) supporting WLAN Access
    • Enhanced LTE-WLAN Aggregation (LWA)
    • Enhanced LTE WLAN Radio Level Integration with IPsec Tunnel (eLWIP)
    • Positioning Enhancements for GERAN
    • New GPRS algorithms for EASE
    • RRC optimization for UMTS
    • Multi-Carrier Enhancements for UMTS
    • DTX/DRX enhancements in CELL_FACH
    • LTE radio improvements
    • Enhancements on Full-Dimension (FD) MIMO for LTE
    • Downlink Multiuser Superposition Transmission for LTE
    • Performance enhancements for high speed scenario in LTE
    • Control and User Plane Separation (CUPS) of EPC nodes
    • Paging Policy Enhancements and Procedure
    • Shared Subscription Data Update
    • Service Domain Centralization
    • Control of Applications when Third party Servers encounter difficulties
    • PS Data Off Services
    • Enhancement to Flexible Mobile Service Steering 
    • Sponsored data connectivity improvements
    • Group based enhancements in the network capability exposure functions
    • Improved operator control using new UE configuration parameters
    • Charging and OAM stand alone improvements
    • Rel-14 Charging
    • ...

    Further Reading:


    Tuesday, 27 June 2017

    Mission Critical Services update from 3GPP - June 2017


    3GPP has published an overview of what has been achieved so far in the Mission Critical and also provides an outlook of what can be expected in the near future. A more detailed paper summarizing the use cases and functional aspects of Rel-13, Rel-14 and upcoming Rel-15 will be published later this year.

    Mission Critical Services – Detailed List of Rel-13, Rel-14 and Rel-15 Functionalities

    Rel-13 MCPTT (completed 2016)
    • User authentication and service authorization
    • Configuration
    • Affiliation and de-affiliation
    • Group calls on-network and off-network (within one system or multiple systems, pre-arranged or chat model, late entry, broadcast group calls, emergency group calls, imminent peril group calls, emergency alerts)
    • Private calls on-network and off-network (automatic or manual commencement modes, emergency private calls)
    • MCPTT security
    • Encryption (media and control signalling)
    • Simultaneous sessions for call
    • Dynamic group management (group regrouping)
    • Floor control in on-network (within one system or across systems) and in off-network
    • Pre-established sessions
    • Resource management (unicast, multicast, modification, shared priority)
    • Multicast/Unicast bearer control, MBMS (Multimedia Broadcast/Multicast Service) bearers
    • Location configuration, reporting and triggering
    • Use of UE-to-network relays
    Rel-14 MC Services (completed 2017)
    MC Services Common Functionalities:
    • User authentication and service authorization
    • Service configuration
    • Affiliation and de-affiliation
    • Extended Location Features
    • (Dynamic) Group Management
    • Identity management
    • MC Security framework
    • Encryption (media and control signalling)
    MCPTT Enhancements:
    • First-to-answer call setup (with and without floor control)
    • Floor control for audio cut-in enabled group
    • Updating the selected MC Service user profile for an MC Service
    • Ambient listening call
    • MCPTT private call-back request
    • Remote change of selected group
    MCVideo, Common Functions plus:
    • Group Call (including emergency group calls, imminent peril group calls, emergency alerts)
    • Private Call (off-network)
    • Transmission Control
    MCData, Common Functions plus:
    • Short Data Service (SDS)
    • File Distribution (FD) (on-network)
    • Transmission and Reception Control
    • Handling of Disposition Notifications
    • Communication Release
    Rel-15 MC Services (in progress)

    MC Services Common Functionalities Enhancements:
    • Enhanced MCPTT group call setup procedure with MBMS bearer
    • Enhanced Location management, information and triggers
    • Interconnection between 3GPP defined MC systems
    • Interworking with legacy systems

    MCPTT Enhancements:
    • Remotely initiated MCPTT call
    • Enhanced handling of MCPTT Emergency Alerts
    • Enhanced Broadcast group call
    • Updating pre-selected MC Service user profile
    • Temporary group call - user regroup
    • Functional alias identity for user and equipment
    • Multiple simultaneous users
    MCVideo Additions:
    • Video push
    • Video pull
    • Private call (on-network)
    • Broadcast Group Call
    • Ambient Viewing Call
    • Capability information sharing
    • Simultaneous Sessions
    • Use of MBMS transmission
    • Emergency and imminent peril private communications
    • Primary and Partner MC system interactions for MCVideo communications
    • Remote video parameters control capabilities

    MCData Additions:
    • MCData specific Location
    • Enhanced Status
    • Accessing list of deferred communications
    • Usage of MBMS
    • Emergency Alert
    • Data streaming
    • File Distribution (FD) (off-network)
    • IP connectivity

    Release-14 features will be available by end of September 2017 and many Release-15 features, that is being hurried due to 5G will be available by June 2018.

    For more details, follow the links below:



    Sunday, 10 May 2015

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



    "TV isn't dying, it's having babies." This quote made my day. I have argued a few times in the past that terrestrial broadcasting will continue working and will be probably the most popular approach for a long time to come. The way things work with it may change. Multi-screen is one possible approach but you may have more interactions like 'red button functionality', etc.
    Anyway, in Europe 800MHz spectrum has been cleared for use by Mobile Broadband technologies (LTE mainly). 700MHz is planned to be cleared as well by 2020, as per the suggestion in Lamy report. The other UHF band from 470MHz to 694MHz would be left as it is until 2030, with a review planned in 2025.

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

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




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




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



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

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



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



    Thursday, 26 June 2014

    LTE-Broadcast: Reality check


    When I wrote my blog post about why the 'Cellular Broadcast may fail again' for the Cisco SP Mobility blog, I did not realise that this would become so popular and there would be so many people writing to me to tell me why and how my assumptions are wrong and how they plan to succeed. I have not yet received a successful reasoning on why people disagree with my article and where I am wrong.

    In the Video Over LTE Summit just concluded, I did not get a chance to see all the LTE-B presentations but the ones that I saw, were not convincing enough, except for one by Erol Hepsaydir, of '3' UK, that I explain in the end.

    Here is my presentation from that event:



    The conclusion is not self-explanatory so here it is in my own words.


    I am not opposed to the operators trying LTE-B out. I wish more operators do try and hopefully we can have a model where the technology can succeed. When operators succeed in a new technology, it benefits the whole mobile ecosystem directly or indirectly. The operators have to be prepared that they may not see any return. This should not discourage them because the learnings from this may benefit in something else. The customer and their loyalty is more important. We should try and provide them with a value addition rather than think of this as a new source of revenue. People are not interested in watching the same stuff they watch on the terrestrial TV on their small devices; unique and maybe tailored content would help. Finally, don't make the billing model too complex so the users shy away from trying this new technology.

    The final presentation of the event was delivered by Erol Hepsaydir of the UK operator '3'. He said that from their point of view, they are trying to have eMBMS to create additional capacity in the network. If they know that many people watch news on different apps and websites, they can offer this as a free service over broadcast. What this means is that they have gained customer loyalty and also free up the capacity for other users who are doing other data related activities. I think this is a very clever approach. He did mention though that they are only in the simulation stages and have not tried it out practically. 

    Thursday, 10 April 2014

    LTE-Broadcast of the operator, by the operator, for the operator!

    Heard an insightful talk from EE in the CW event this week. While I agree with the intentions and approaches, I still think there may be too many assumptions in the eMBMS business model. I have made my intentions known all but too well in my earlier blog post here.

    Some of the insights that I have gained in the last couple of months with regards to the way operators are planning to use the LTE broadcast is through the OTT Apps. Take for instance an OTT application like iPlayer or Hulu and some popular program is about to be broadcast, that program can be sent using LTE-B. Now some people may watch on the time (linear) and some may watch at a later time (non-linear or time-shifted). The App can be intelligent enough to buffer the program so there is no delay required when the user wants to watch it. This can open all sorts of issues like the user may have watched one episode on his device while the current one is being watched on his digital television. While the program is being buffered the battery and memory of the device is being consumed. How long should a program be stored on the device. There can be many other open issues.

    Another question I had was how would the users be billed for these things. Would it be free since the data was received over LTE-B. Matt Stagg from EE said that the users would be billed normally as if they received it in case of streaming. He was more pragmatic though. He clearly said that in the initial phase everything would have to be free. This will ensure that any technical issues are ironed out and at the same time the users become familiar with how all this works.

    Finally a point worth remembering, users prefer watching videos on their tablets. Most tablets are WiFi only which means the LTE-Broadcast wont work on it.

    The presentation is embedded as follows:



    Wednesday, 8 January 2014

    LTE-Broadcast (eMBMS) may fail again

    I recently wrote a blog post for the Cisco SP Mobility blog on why the Cellular Broadcast may fail again (complete article embedded below). My main point is that small screen devices are not really suitable for mobile TV kind of applications. The larger devices like tablets are but since they do not contain the (U)SIM card, its not possible for them to receive cellular broadcast signals.

    Anyway, I came across this picture below from the recent Ericsson Mobility report:

    This highlights my point that more people are now preferring to watch videos over the tablets as compared to the smaller smartphone screens. Even though the other diagrams in the article does show a significant amount of users using their smartphones for viewing movies and long clips, my belief is that this will reduce over the time as the tablet share increases



    A recent Business Insider article says that "One In Every 5 People In The World Own A Smartphone, One In Every 17 Own A Tablet". Once the users move to using bigger screens, their preferences on how they watch videos will definitely change.

    A real interesting chart would be to show users viewing habits based on the screen size. Phablets are generally classified as smartphones but can be substitutes for tablets in many scenarios. They could definitely help the Mobile TV viewing habits on the smartphones.

    Anyway, here is the complete article:



    Monday, 23 September 2013

    Push to talk (PTT) via eMBMS


    I was talking about push to share back in 2007 here. Now, in a recent presentation (embedded below) from ALU, eMBMS has been suggested as a a solution for PTT like services in case of Public safety case. Not sure if or when we will see this but I hope that its sooner rather than later. Anyway, the presentation is embedded below. Feel free to add your comments:



    Thursday, 9 May 2013

    eMBMS Physical layer aspects from T&M point of view

    Based on the success of the recent posts on eMBMS, here and here, this final post on this topic is a look at physical layer perspective from Test and Measurement point of view. Slides kindly provided by R&S



    A video of this is also available on Youtube, embedded below: