NEC on 'Radio Access Network' (RAN) Sharing

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.

“NEC’s Approach towards Active Radio Access Network Sharing” from Zahid Ghadialy

Access Class Barring in LTE using System Information Block Type 2

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.

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

eMBMS: Broadcast and Multicast in LTE from Zahid Ghadialy

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

LTE for Public Safety Networks

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

What is WebRTC and where does it fit with LTE and IMS

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

WebRTC Technical Overview and Introduction from Zahid Ghadialy

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

Extending 4G Communications with WebRTC IMS and WebRTC from Zahid Ghadialy

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.

LTE-B, LTE-C, ... , LTE-X

Please make sure to read the comment from Kevin Flynn of 3GPP at the end

When I saw this picture above, I started wondering what LTE-B, etc. and started digging a bit deep. Came across this Ericsson presentation (embedded below) that shows the breakdown.

To just be sure that this is not Ericsson specific term, I also found a presentation by NTT Docomo (embedded below)

So I guess using LTE-B, LTE-C, etc. is better than saying 4.1G, 4.2G, etc. as we did in case of 3G/HSPA.


The presentations from Ericsson and NTT Docomo embedded below, available to download from Slideshare.

LTE evolution: Beyond lte-advanced from Zahid Ghadialy

Future Radio Access, M2M and Grand Societal Challenges from Zahid Ghadialy

Rel-11/12 3GPP Security Update

Here is the latest Security Update from 3GPP, presented in the 8th ETSI Security Workshop Jan 16-17 2013.

3GPP Security Update - Jan. 2013 from Zahid Ghadialy

All presentations are available from here to download.

Related blog posts:

• Quick update on 3GPP Release-12 progress
• The four C's of Release-12 enhancements
• Quick update on LTE Release 11 Work and Study Items
• 3GPP LTE Security Aspects
• Evolution of 3GPP Security
• 2 Presentations on Mobile technology Security

By the way, I will also be present in the Network Security conference in London in May 2013

Public Safety Communications using LTE

Public Safety Communications using LTE from Zahid Ghadialy

2 Presentations on Mobile technology Security

Present and future Standards for mobile internet and smart phone information security from Zahid Ghadialy

Other related posts:

• Evolution of 3GPP Security
• 'Mapped Security' Concept in LTE
• 3GPP LTE Security Aspects
• New Security Algorithms in Release-11
• 6th ETSI Security Workshop

Half Duplex Operation (HD-FDD) in LTE

It was interesting to hear the other day that there is an option for HD-FDD but it is still undergoing investigation and not standardised yet. From what I hear, operators are showing an interest and we may see it coming to an operator near us in the next couple of years.

Complete presentation below:

Half Duplex Operation in Multimode/Multiband/MIMO-capable Handsets from Zahid Ghadialy

The advantages are obvious but probably the only reason this was not standardised actively is probably because then peak rates often quoted when promoting technology will be halved. The economy of scale is also important and we may not see this becoming popular unless many operators decide together to push for this.

Other posts of interest:

• Quick Introduction to LTE-Advanced
• Quick update on 3GPP Release-12 progress
• TD-LTE in China: Progress and Plan

'LTE' and 'Small Cells' specific applications

Some 4 years back, I posted my first presentation here, titled "LTE Femtocells: Stepping stone for 'killer apps' presentation". I had couple of apps in mind that I thought could benefit from both LTE and Small Cells (or Femtocells to be specific).

The first was your phone acting as a Wireless Hard Disk Drive (HDD) that can be used to store things remotely in a server somewhere. This is similar to what is known as the Cloud nowadays.

Picture Source: Dialaphone.

The other day when I read why LTE is suitable for cloud connectivity, I could see that my old idea could start to become a reality. The article is here. Selective abstract as follows:

The LTE network lends itself well to cloud connectivity because it:

• provides high-bandwidth connections
• is IP- and Ethernet-oriented, the technologies used to connect to the cloud and within data centers
• offers tools that operators didn't have in 2G and 3G (such as more granular ability to manage traffic flows and a better, DPI-based view of traffic running on the network)
• features low latency, which is vital to the small flows and sessions that characterize M2M communications.

The rise of both cloud services and LTE creates a virtuous cycle. Cloud services continue to grow, which helps operators sustain their LTE business model. That growth enables them to accelerate LTE investments. Then operators can support new types of enterprise services, including cloud-based applications.

To take full advantage of this opportunity, operators have to deploy the right backhaul infrastructure. In addition to IP awareness and content awareness, the right backhaul network can leverage the technical advantages that LTE presents:

• flattened architecture that helps distribute compute and storage resources
• seamless migration from 2G and 3G for various physical mediums and networking protocols
• an increase in capacity that starts to put mobile connectivity on par with fixed broadband access.

My reasoning for Small Cell here is, in most cases when you are doing operations that require large amounts of data to be transferred, you will be indoors, either at home or in office or in a low mobility scenario. The requirement for high security and at the same time high speed data transfer that should not be affected by other users in the cell (capacity issues) can be easily solved by using a Small cell (Femtocell for indoors, Metrocell for outdoors).


The other application I had in mind was the Home Security System. I read the following on TotalTele the other day:

3UK's wholesale division on Friday detailed plans to capture high-margin machine-to-machine traffic by partnering with service providers that are likely to have higher-than-average bandwidth requirements.

As a 3G-only operator, the company cannot go after high volume, low margin M2M traffic because it typically only requires a 2G connection. However, there are opportunities to use its 3G network to address more data-hungry verticals that will generate higher traffic volumes.

"The margin on one CCTV M2M connection is more than 50 times bigger than the margin on a smart meter connection," claimed Tom Gardner, lead wholesale manager at 3UK, during Breakfast with Total Telecom in London.

"There is one CCTV camera for every 14 people in the U.K.," he said. "If I can put a SIM in every one of them I'll be a very happy man."

3UK, which on Thursday launched its Ericsson-based wholesale M2M platform, sees a big opportunity in CCTV, particularly for mobile and temporary installations at festivals, for instance. Other potentially lucrative sectors it has identified include digital signage, back-up for fixed Internet connections, and backhauling WiFi traffic from public transport.

I am sure some of you may be thinking that '3' UK uses HSPA network, not LTE, which is true. The point here is that it could be done better using LTE and Small Cells.

The reason for using LTE would be to provide higher data rates, meaning that information can be sent faster, with higher resolution and more regularly. This will help identify the problems earlier. If the CCTV is used indoors or in high usage areas, it would make sense that it connects via Small Cell to avoid creating capacity issues in the Macro network.

Here is the embed again, of my old presentation just in case if it interests you:

Lte Femtocells: Stepping stone for killer applications from Zahid Ghadialy

Mobile Broadband Speeds: How is 4G different from 3G?

I wrote this answer on Quora and as of yesterday there were 20+ upvotes. So here is an embed for the same:

Read Quote of Zahid Ghadialy's answer to Mobile Broadband: How is 4G different from 3G? on Quora

CSFB Performance

Here is another presentation from Qualcomm from the '4G World'.

CSFB Performance from Zahid Ghadialy

With regards to SI Tunneling mentioned in the presentation, I found the following in another Qualcomm whitepapers:


With Release 9 Enhanced Release with Redirection—SI Tunneling, the device follows 3GPP release 9, where SIB information can be tunneled from the target Radio Access Network (RAN) via the core network to the source RAN and be included in the redirection message sent to the device. This can avoid reading any SIBs on the target cell. 

The predominant solutions deployed today are based on Release 8 Release with Redirection — SIB Skipping, in order to achieve good call setup times, good reliability, and simplify deployments. It is anticipated that Release 9 Enhanced Release with Redirection will be deployed in the near future. At this time, there is not as much push for handover-based CSFB since both Release 8 Release with Redirection—SIB Skipping and Release 9 Enhanced Release with Redirection—SI Tunneling have largely addressed any call setup time issues that may have existed with the Basic Release with Redirection solution.

I have blogged on this topic before, here.

More on Dual Radio here and SVLTE here.

17 LTE Voice Modes

No wonder why LTE chipsets are complicated.

From Qualcomm's presentation in 4G World, available here.

Extended Access Barring (EAB) in Release 11 to avoid MTC overload

M2M is going to be big. With the promise of 50 Billion devices by 2020, the networks are already worried about the overloading due to signalling by millions of devices occurring at any given time. To counter this, they have been working on avoiding overloading of the network for quite some time as blogged about here.

The feature to avoid this overload is known as Extended Access Barring (EAB). For E-UTRAN, in Rel-10, a partial solution was implemented and a much better solution has been implemented in Rel-11. For GERAN a solution was implemented in Rel-10. The following presentation gives a high level overview of EAB for E-UTRAN and GERAN.

3GPP Enhancements for Machine Type Communications Overview from Zahid Ghadialy

In Rel-11, a new System Information Block (SIB 14) has been added that is used specifically for EAB. Whereas in Rel-10, the UE would still send the RRCConnectionRequest, in Rel-11, the UE does not even need to do that, thereby congesting the Random Access messages.

The following is from RRC 36.331 (2012-09)
***

–                SystemInformationBlockType14

The IE SystemInformationBlockType14 contains the EAB parameters.

SystemInformationBlockType14 information element

-- ASN1START

SystemInformationBlockType14-r11 ::= SEQUENCE {

    eab-Param-r11                        CHOICE {

       eab-Common-r11                       EAB-Config-r11,

       eab-PerPLMN-List-r11                 SEQUENCE (SIZE (1..6)) OF EAB-ConfigPLMN-r11

    }                                                  OPTIONAL, -- Need OR

    lateNonCriticalExtension             OCTET STRING          OPTIONAL, -- Need OP

    ...

}

EAB-ConfigPLMN-r11 ::=               SEQUENCE {

    eab-Config-r11                   EAB-Config-r11            OPTIONAL -- Need OR

}

EAB-Config-r11 ::=               SEQUENCE {

    eab-Category-r11                 ENUMERATED {a, b, c, spare},

    eab-BarringBitmap-r11            BIT STRING (SIZE (10))

}

-- ASN1STOP

SystemInformationBlockType14 field descriptions
eab-BarringBitmap Extended access class barring for AC 0-9. The first/ leftmost bit is for AC 0, the second bit is for AC 1, and so on.
eab-Category Indicates the category of UEs for which EAB applies. Value a corresponds to all UEs, value b corresponds to the UEs that are neither in their HPLMN nor in a PLMN that is equivalent to it, and value c corresponds to the UEs that are neither in the PLMN listed as most preferred PLMN of the country where the UEs are roaming in the operator-defined PLMN selector list on the USIM, nor in their HPLMN nor in a PLMN that is equivalent to their HPLMN, see TS 22.011 [10].
eab-Common The EAB parameters applicable for all PLMN(s).
eab-PerPLMN-List The EAB parameters per PLMN, listed in the same order as the PLMN(s) occur in plmn-IdentityList in SystemInformationBlockType1.

***

Here is my attempt to explain the difference in overload control mechanism in Rel-8, Rel-10 and Rel-11. Please note that not actual message names are used.

As usual, happy to receive feedback, comments, suggestions, etc.

LTE: What is a Tracking Area

Even though I have known tracking area for a long time, the other day I struggled to explain exactly what it is. I found a good explanation in this new book 'An Introduction to LTE: LTE, LTE-Advanced, SAE and 4G Mobile Communications By Christopher Cox'. An extract from the book and Google embed is as follows:

The EPC is divided into three different types of geographical area, which are illustrated in Figure 2.6. (see Embed below).

An MME pool area is an area through which the mobile can move without a change of serving MME. Every pool area is controlled by one or more MMEs, while every base station is connected to all the MMEs in a pool area by means of the S1-MME interface. Pool areas can also overlap. Typically, a network operator might configure a pool area to cover a large region of the network such as a major city and might add MMEs to the pool as the signalling load in that city increases.

Similarly, an S-GW service area is an area served by one or more serving gateways, through which the mobile can move without a change of serving gateway. Every base station is connected to all the serving gateways in a service area by means of the S1-U interface. S-GW service areas do not necessarily correspond to MME pool areas.

MME pool areas and S-GW service areas are both made from smaller, non-overlapping units known as tracking areas (TAs). These are used to track the locations of mobiles that are on standby and are similar to the location and routing areas from UMTS and GSM.

LTE, M2M Device Addressing and IMSI

I was made aware of the following statement on the Verizon wireless brochure:

LTE’s inherent support for IPV6 addressing and IMSI-based telephone number identifiers makes mass deployments over LTE more easily achievable. The deployment of large numbers of mobile devices (think tens of thousands) becomes much more feasible because of LTE’s use of 15-digit IMSI telephone number identifiers for large-scale deployments, such as M2M or embedded wireless applications. 3G network technologies were limited by their use of 10-digit telephone number identifiers, which made large-scale deployments more difficult. With LTE, mass deployment of wireless services and applications, such as VoIP, smart metering, vending, and telematics, is now practical.

Now we know about the much touted 50 Billion connections by 2025 of which the majority would be M2M devices. So how are we going to handle the issue of addressing these many devices.

In the earlier presentation here, there was a mention of the direction for the solution as below:

The IMSI structure is as shown above. So depending on how it is used this can help alleviate the number shortage problem. 3GPP TR 23.888 gives the following information:

5.13      Key Issue - MTC Identifiers

5.13.1    Use Case Description

The amount of MTC Devices is expected to become 2 orders of magnitude higher than the amount of devices for human to human communication scenarios. This has to be taken into account for IMSI, IMEI and MSISDN. Regulatory bodies indicate shortages of IMSIs and MSISDNs.

The MTC Feature PS Only in TS 22.368 [2] includes a requirement that PS Only subscriptions shall be possible without an MSISDN. In principle an MSISDN is not used in any of the PS based signalling procedures. However, it will have to be assured that all PS procedures indeed work and subscriptions can be uniquely identified without providing an MSISDN. Furthermore, TS 22.368 [2] specifies that remote MTC Device configuration shall be supported for PS only subscriptions without an MSDISDN assigned. Current remote MTC Device configuration solutions (i.e. Device Management and Over-the-Air configuration) are based on SMS, which assumes the use of MSISDNs. So a solution to support remote MTC Device configuration that does not require the use of MSISDNs is needed.

The identifiers can be categorised into:

-     Internal Identifiers: used within the 3GPP system to identify a UE using a subscription (or the subscription itself e.g. when the UE is not registered).

-     External Identifiers: used from outside the 3GPP system (e.g. at the MTCsp interface), to refer to a UE using a subscription (or the subscription itself e.g. when the UE is not registered).

5.13.2    Required Functionality

-     It shall be possible to uniquely identify the ME.

NOTE 1:   This requirement relates to the ME which is generally identified by the IMEI.

-     It shall be possible to uniquely identify the UE using a subscription or the subscription itself.

NOTE 2:   The two requirements above also apply to human-to-human communications. However, for Machine-Type Communication identifiers will have to be able to cater for a number of identifiers up to two orders of magnitude higher than for human-to-human communications.

-     It shall be possible to use the following identifiers:

1.       IMSI, for internal usage within the 3GPP operator domain, and either

2.       E.164 MSISDN, for usage outside the 3GPP operator domain, or

3.       Unique identifier (e.g. FQDN), other than E.164 MSISDN, for usage outside the 3GPP operator domain.

NOTE 3: Use of IMSI outside the 3GPP operator domain is an operator option (i.e. not subject to standardization)

-     If no (unique or common) MSISDN is assigned to a PS only subscription, the Internal Identifier (IMSI) shall be used as charging identifier.

-     It shall be possible to associate one or more External Identifiers to the same Internal Identifier (e.g. several MSISDNs associated with the same IMSI).

-     Globally unique External Identifiers shall be supported for identifying UEs used for MTC that must be globally reachable (i.e. irrespective of which mobile operator owns the subscription)

-     Operator specific External Identifiers (e.g. based on a private numbering plan) may be supported for identifying UEs used for MTC that have to be reachable only from the operator domain to which they are subscribed.

-     The Internal Identifier shall be globally unique.

-     Remote MTC Device configuration shall still be supported for subscriptions without an MSISDN.

NOTE 4:   Current remote MTC Device configuration solutions (i.e. Device Management and Over-the-Air configuration) are based on SMS, which assumes the use of MSISDNs.

Any more information on this subject, more than welcome.

Ovum: Global LTE Pricing Strategies

Here is another interesting presentation from the LTE World Summit:

Steven hartley ovum-thurs_zone-2_masterclass-2_thurs from ceobroadband

Other related posts:

• Right Pricing LTE ... and Mobile Broadband in general
• Right Pricing Mobile Broadband

M-health and LTE

The last presentation from FWIC on m-Health was quite popular so I decided to add this new presentation from the LTE World Summit:

Robert istepanian kingston-university-masterclass_wed_zone-2 from ceobroadband

UK: Spectrum, Operators, Vendors and LTE

So LTE (or '4G') is about to be launched in the UK as announced yesterday. Its going to be branded as 4GEE.

Here is a summary of the Spectrum in the UK that will be used for LTE and would be auctioned by Ofcom.

Here is the current allocation of Spectrum in the UK

The above pics are from a presentation by Ofcom in LTE World Summit 2012 in Barcelona, available here.

The last table is from an Ofcom document here. Its very interesting read. For example I didnt know that The L-band was the first major part of Ofcom spectrum awards programme relevant to mobile services. It consists of 40MHz between 1452MHz and 1492MHz. The auction took place in May 2008, in which Qualcomm won the entirety of the available spectrum.

Here is the summary of the operators working on LTE:


Everything Everywhere (EE = Orange + T-Mobile) - They are calling their '4G' service as EE, covering up to 70% of the UK by the end of 2013. Network kit provided by Huawei.

Three - Samsung will provide the Radio Access Network, and the core infrastructure, for Three's LTE (4G) network. That includes the base stations, and radio core. 3 UK has agreed to purchase 2 x 15 MHz of 1800 MHz spectrum from Everything everywhere, and plans commercial launch of LTE service in 2013.

Telefonica (O2) trial network - Equipment supplied by Nokia Siemens Networks (NSN) for both the Radio and Core network elements. Backhaul for the 4G trial network has been provided using Microwave Radio Equipment from Cambridge Broadband Networks Limited, NEC and Nokia Siemens Networks.

Updated 13/09/12 - 11:25

UK Broadband rolled out the first commercial TD-LTE network in London back in February (available to customers since May 2012). The equipment is provided by Huawei. They have 40MHz in Band 42 (3.5GHz) and 84MHz in band 43 (3.6GHz).

Vodafone - No news.


Anything else I missed?