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Latest news and information on 3G, 4G, 5G wireless and technologies in general.

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    Came across this interesting Video on Youtube explaining 802.11u that is embedded below.




    A bit more detailed presentation on the same topic by Ruckus is also embedded below:


    Related posts:



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    Its been a while I posted something on DAS (a.k.a. Distributed Antenna System). The articles I have posted have been mainly from AT&T and are here, here and here.

    Picture source: The IET

    Recently I read something interesting from IDG here:
    According to Rob Bruce, Chief Operating Officer at distributed antenna system (DAS) vendor Axell Networks, a building is an asset, and that asset wants to deliver all the services it can in the simplest and most economical way.
    "You wouldn't put five separate lighting systems into a building because there are five separate tenants in that building. You would put one in, and it becomes a utility for that building," Bruce told Techworld.
    "Our view of life is it's the same for cellular coverage. You put one system in which covers the building. That is then a utility for the building, and operators can then connect into that infrastructure - that's how a DAS system works."
    Bruce said that small cells are very good for single operator environments, when a single operator wants to add some capability into a particular area. But if they want to put multiple technologies into that environment then they have to put in multiple small cells.
    So if a company in the UK wants to put GSM, UMTS and LTE into an office block, it has to install three small cells. If it wants to make that truly operator agnostic, it will probably have to put in 12 units, because each of the four operators uses at least three spectrum bands.
    Axell Wireless recently installed a multi-operator DAS in The Shard in London, using 20 remote units to cover the whole building. Bruce claimed that, if the same thing had been done using small cells, it would involve over 100 units.
    "So the building owner is saying I've got 100 lumps of intelligent electronics gadgetry that is scattered all over my building, and there's 4 different operators wanting access to all those different things in private flats, hotels and offices - it's just an operational nightmare," said Bruce.
    Complete article is available here.

    This is an interesting point because the Small Cells are still not evolved enough so that a single one can serve multiple operators, etc. Note that I am differentiating the closed residential femtocells from the public access small cells. Maybe a service such as FaaS or 'Femto as a Service' can help solve this problem. Based on my previous sentences, some of you may say that it should be called Small Cell as a Service (SCaaS) rather than FaaS but unfortunately that term has come to mean something else as can be seen here.

    While initially the in-building solutions were mainly for coverage reasons, this may no longer be the only reason. Capacity is also an issue, especially in-building. Small cells can certainly help in the capacity area much more than DAS. Fortunately as most new phones are coming with inbuilt Wi-Fi chipsets and WiFi is available indoors in plenty, the capacity issue may no longer be a problem indoors. Again this is an area where we can have lots of discussions and each party with a vested interest can argue their case.

    Here are couple of interesting videos from youtube that explain DAS:




    There is also an interesting presentation by NEC in the Small Cell Americas event, embedded below:




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    This simple video from MWC should give an idea on what WebRTC is and can do:


    So what exactly WebRTC is in technical terms. Here is a recent presentation from WebRTC Conference and Expo



    And here is another presentation that explains where it fits in with the LTE Architecture.



    Dean Bubley from Disruptive Analysis has writted extensively on this topic and his recent post "Is the telephony "threat" from VoIP & WebRTC about competition or contextualisation?" is an interesting read.

    Iain Sharp from Netovate recently pointed out that 3GPP have 'nearly' approved a work item for WebRTC access to IMS.

    It would be interesting to see how operators will view WebRTC. As an opportunity or as a threat. Please feel free to air your opinions via comments.

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    M2M was again in the news recently when a new report suggested that it would be $1 Trillion industry. Back in december I posted a detailed presentation on M2M that has now crossed over 6K views. This shows that there is an appetite for this topic. So here is a three part presentation on M2M and IoT. In fact as I pointed out in a post last year, it is very often referred to as IoE (Internet of Everything) rather than IoT (Internet of Things). If this is a topic close to your heart then please do come to the Future of Wireless International Conference (FWIC) organised by Cambridge Wireless on 1st and 2nd July 2013. Details here.











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    The last presentation on this topic couple of months back has reached nearly 7K views so here is another one from a recent article on the same topic from IEEE Communications Magazine




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    One of the LTE-B proposals by NTT Docomo is this 'Phantom Cell' concept. A recent article from the IEEE Communications Magazine expands this further:


    Phantom Cell Concept— In the current deployments, there are a number of capacity solutions for indoor environments such as WiFi, femtocells, and in-building cells using distributed antenna systems (DAS). However, there is a lack of capacity solutions for high-traffic outdoor environments that can also support good mobility and connectivity. Thus, we propose the concept of macro-assisted small cells, called the Phantom Cell, as a capacity solution that offers good mobility support while capitalizing on the existing LTE network. In the Phantom Cell concept, the C-plane/U-plane are split as shown in Fig. The C-plane of UE in small cells is provided by a macrocell in a lower frequency band, while for UE in macrocells both the C-plane and U-plane are provided by the serving macrocell in the same way as in the conventional system. On the other hand, the Uplane of UE in small cells is provided by a small cell using a higher frequency band. Hence, these macro-assisted small cells are called Phantom Cells as they are intended to transmit UE-specific signals only, and the radio resource control (RRC) connection procedures between the UE and the Phantom Cell, such as channel establishment and release, are managed by the macrocell.

    The Phantom Cells are not conventional cells in the sense that they are not configured with cell specific signals and channels such as cell-ID-specific synchronization signals, cell-specific reference signals (CRS), and broadcast system information. Their visibility to the UE relies on macrocell signaling. The Phantom Cell concept comes with a range of benefits. One important benefit of macro assistance of small cells is that control signaling due to frequent handover between small cells and macrocells and among small cells can be significantly reduced, and connectivity can be maintained even when using small cells and higher frequency bands. In addition, by applying the new carrier type (NCT) that contains no or reduced legacy cell-specific signals, the Phantom Cell is able to provide further benefits such as efficient energy savings, lower interference and hence higher spectral efficiency, and reduction in cellplanning effort for dense small cell deployments.

    To establish a network architecture that supports the C/U-plane split, and interworking between the macrocell and Phantom Cell is required. A straightforward solution to achieve this is to support Phantom Cells by using remote radio heads (RRHs) belonging to a single macro eNB. This approach can be referred to as intra-eNB carrier aggregation (CA) using RRHs. However, such a tight CA-based architecture has some drawbacks as it requires single-node operation with low-latency connections (e.g., optical fibers) between the macro and Phantom Cells. Therefore, more flexible network architectures should be investigated to allow for relaxed backhaul requirements between macro and Phantom Cells and to support a distributed node deployment with separated network nodes for each (i.e., inter-eNB CA).



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    Interference Management is a big topic in HetNet's. An earlier blog post here on similar topic was very popular. The above picture shows a Heterogeneous cellular network topology incorporating different forms of small cell deployments as an overlay on the macrocell network. Small cells would generally use secure tunnels back to the core network using existing broadband infrastructure. Whereas in the HCS (Hierarchical Cell Structures), different layers have different frequencies, thereby not causing radio frequency interference, in HetNets same frequencies can be used between different layers. The same frequencies can cause radio frequency Interference and necessitates the use of advanced Interference avoidance techniques.

    CTTC has another interesting presentation on Interference Management in HetNets that I am embedding below as slides and video:






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    Interesting article from the recent IEEE Comsoc magazine. Table 1 on page 5 is an interesting comparison of how different players reach the magical '1000x' capacity increase. Even though Huawei shows 100x, which may be more realistic, the industry is sticking with the 1000x figure. 

    Qualcomm is touting a similar 1000x figure as I showed in a post earlier here.

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  • 04/14/13--23:30: Cell Range Expansion (CRE)


  • The intention of the Pico Cells is to offload traffic from the Macro cells to increase the system capacity. As a result, when Macro cell becomes overloaded, it would make sense to offload the MUE’s in the vicinity of the Pico cell to it. This can/should be done even if the UE is receiving a better signal from the Macro cell. The expansion of the range of the Pico cell is termed as CRE or Cell Range expansion.

    To make sure that the UE does not fail in the handover process, the Time domain ICIC should be used and Macro cell should use ABS. The UE’s can be configured to do measurements on the Pico when the Macro is using ABS. The MUE now reports the Measurement reports to the Macro and are handed over to the Pico to act as PUE.


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    Its been a while since I last posted something on eMBMS. Its been even longer that we saw anything official from 3GPP on eMBMS. Recently I have seen some operators again starting to wonder if eMBMS makes business sense, while the vendors and standards are still working hard on the technology.

    Not so long back, HEVC/H.265 codec was standardised. This codec helps transmission of the video using half the bandwidth. This means that it would be economical to use this for broadcast technologies. No wonder Nokia, Thompson and NTT Docomo are excited.

    Interesting picture from a Qualcomm presentation (embedded in the end) shows how different protocols fit in the eMBMS architecture. My guess would be that the HEVC  may be part of the Codecs.



    On the operators front, Korea Telecom (KT) has intentions for countrywide rollout. Korea is one of the very few countries where end users have embraced watching video on small form factors. Verizon wireless has already signalled the intention to rollout eMBMS in 2014; its working out a business case. Telenor Sweden is another player to join the band with the intention of adopting Ericsson's Multi screen technology.

    One of the main reasons for the lack of support for the 3G MBMS technology was not a compelling business case. Qualcomm has a whitepaper that outlines some of the potential of LTE Broadcast technology here. A picture from this whitepaper on the business case below:

    Finally, a presentation from Qualcomm research on eMBMS embedded below:




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    Continuing on the eMBMS theme. In the presentation in the last post, there was introduction to the eMBMS protocols and codecs and mention about the DASH protocol. This article from the IEEE Communications magazine provides insight into the working of eMBMS and what potential it holds.



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    Couple of news items from earlier this month from Japan about the nottv Mobile TV service. First was that it celebrated its 1st anniversary. The second is that it has racked up 700,000 subscribers; less than a million that it was expecting. I have posted in the past about attempts by various parties on Mobile TV that was unsuccessful. You can read more about that here and here.

    One of the ways Mobile TV can provide additional value as compared to the normal TV is through audience participation. NOTTV is working to be able to provide this feature in future. Also it uses the ISDB-Tmm standard for broadcast. Hopefully in future when eMBMS is more popular, it may be used to transmit Mobile TV data as well. A picture showing the difference between the ISDB-T and ISDB-Tmm is shown below (from the presentation here)


    A magazine article on NOTTV from the NTT Docomo magazine is embedded as follows:



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    Ericsson recently posted a very good summary video of Release-12 features. My comments and more details are posted below the video:


    You may have noticed that LTE Release 12 is also referred to as LTE-B as I posted in my blog post here. Unfortunately, this terminology is not supported by 3GPP which refers to all advancements of LTE as LTE-A. See comment on the post I just referred.

    The Elevation Beamforming is also referred to as 3D-Beamforming or 3D-MIMO as I show here.

    I havent written any posts on Dual connectivity and not exactly sure how it works but there is an interesting presentation on the Small Cells Enhancements in Release-12 on my blog here.

    You can learn more about the WiFi and EPC Integration here.

    Click on the following Direct Communications, Device to device (D2D) and Public Safety for more information on the topics.

    There are many good presentations on Machine Type Communications (MTC) or M2M that are available on this label here.

    Finally, I havent seen much about the lean carrier but now that I know, will add some information on this topic soon.

    Related links:


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    For more details, you can read Alan Quayle's summary on his blog here.


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    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:


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    Next month we will reach the milestone where the number of active Mobile devices is equal to the number of people in the world. There are many people with more than one active mobile device and there are others who have no devices so the number of active devices will still keep rising for some time to come.

    Embedded below is a presentation by Tomi Ahonen in MMAF 2013, you can see all the presentations from the event on Slideshare here.




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    As per 3GPP TS 22.011 (Service accessibility):

    All UEs are members of one out of ten randomly allocated mobile populations, defined as Access Classes (AC) 0 to 9. The population number is stored in the SIM/USIM. In addition, UEs may be members of one or more out of 5 special categories (Access Classes 11 to 15), also held in the SIM/USIM. These are allocated to specific high priority users as follows. (The enumeration is not meant as a priority sequence):
    Class 15-PLMN Staff;
     -"- 14-Emergency Services;
     -"- 13-Public Utilities (e.g. water/gas suppliers);
     -"- 12-Security Services;
     -"- 11-For PLMN Use.

    Now, in case of an overload situation like emergency or congestion, the network may want to reduce the access overload in the cell. To reduce the access from the UE, the network modifies the SIB2 (SystemInformationBlockType2) that contains access barring related parameters as shown below:




    For regular users with AC 0 – 9, their access is controlled by ac-BarringFactor and ac-BarringTime. The UE generates a random number
    – “Rand” generated by the UE has to pass the “persistent” test in order for the UE to access. By setting ac-BarringFactor to a lower value, the access from regular user is restricted (UE must generate a “rand” that is lower than the threshold in order to access) while priority users with AC 11 – 15 can access without any restriction

    For users initiating emergency calls (AC 10) their access is controlled by ac-BarringForEmergency – boolean value: barring or not

    For UEs with AC 11- 15, their access is controlled by ac-BarringForSpecialAC - boolean value: barring or not.


    The network (E-UTRAN) shall be able to support access control based on the type of access attempt (i.e. mobile originating data or mobile originating signalling), in which indications to the UEs are broadcasted to guide the behaviour of UE. E-UTRAN shall be able to form combinations of access control based on the type of access attempt e.g. mobile originating and mobile terminating, mobile originating, or location registration.  The ‘mean duration of access control’ and the barring rate are broadcasted for each type of access attempt (i.e. mobile originating data or mobile originating signalling).

    Another type of Access Control is the Service Specific Access Control (SSAC) that we have seen here before. SSAC is used to apply independent access control for telephony services (MMTEL) for mobile originating session requests from idle-mode.

    Access control for CSFB provides a mechanism to prohibit UEs to access E-UTRAN to perform CSFB. It minimizes service availability degradation (i.e. radio resource shortage, congestion of fallback network) caused by mass simultaneous mobile originating requests for CSFB and increases the availability of the E-UTRAN resources for UEs accessing other services.  When an operator determines that it is appropriate to apply access control for CSFB, the network may broadcast necessary information to provide access control for CSFB for each class to UEs in a specific area. The network shall be able to separately apply access control for CSFB, SSAC and enhanced Access control on E-UTRAN.

    Finally, we have the Extended Access Barring (EAB) that I have already described here before.

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    Yesterday, I noticed some heavyweights discussing roaming prices on Twitter. It is embedded below using the new Twitter embed feature:


    Those who follow me on Twitter may have noticed me ranting about the roaming prices recently so I thought that this is a perfect opportunity to put my thoughts down.

    As being discussed above, I went on the websites of two UK operators and found out about their roaming rates to India and The USA and they are as follows:


     It should be noted that there is a better rate available with some kind of bundle opt-in from both the operators and I have not shown about the other UK operators but they offer a similar sort of rate so I am not trying to single out O2 and/or Vodafone.

    Since LTE is 'All-IP' network my interest is more from Data point of view rather than the voice point of view. A colleague who went to India recently decided that enough is enough and he bought a SIM in India locally. Apparently is just a bit too difficult to get SIM in India if you are not an Indian resident, nevertheless he somehow managed it. The rates as shown below was INR 24 for 100 MB of data.


    Rs. 24 is something like $0.50 or £0.35. You see my problem regarding the data rates? People may be quick to point out here that India has the cheapest data rates in the world. On the other hand we look at US, the rates are as follows:

    Even if we assume $15 / 1GB data, its far cheaper than the roaming rate which may be something like,  £3/MB = £3000/GB or £6/MB = £6000/GB.

    I blogged about all the interesting developments that have been happening in LTE World Summit regarding the roaming solutions but what is the point of having all these solutions if the operators cant work out a way to reduce these costs. Or is it that they do not want to reduce these costs as they are a good source of income?

    The operators complain that the OTT services are taking business away from them and turning them into dumb data pipes but to a lot of extent its their fault. People like me who travel often dont want to spend loads of cash on data and have worked out a way around it. Most of the places I visit have WiFi, most of my work is not urgent enough and I can wait till I am in a WiFi coverage area. In some parts of the world, still I have to buy an expensive WiFi access but compared to the roaming rates, its still cheap so I have stopped complaining about it. My decision to book a hotel depends of reviews, free breakfast and free WiFi. Some of our clients who give us their phone to use abroad strictly inform us that data should not be turned on unless its a matter of life and death.

    If the operators dont change their strategies and work out a better solution for the roaming rates I am afraid that their short term gains will only lead to long term pains.

    Do you have an opinion? I am interested in hearing.

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    Its been a while we looked at anything to do with Network Sharing. The last post with an embed from Dr. Kim Larsen presentation, has already crossed 11K+ views on slideshare. Over the last few years there has been a raft of announcements about various operators sharing their networks locally with the rivals to reduce their CAPEX as well as their OPEX. Even though I understand the reasons behind the network sharing I believe that the end consumers end up losing as they may not have a means of differentiating between the different operators on a macro cell.

    Certain operators on the other hand offer differentiators like residential femtocells that can enhance indoor coverage or a tie up with WiFi hotspot providers which may provide them wi-fi access on the move. The following whitepaper from NEC is an interesting read to understanding how RAN sharing in the LTE would work.




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