Converged Mobile Offload Architectures

Converged Mobile Offfload Architectures

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LTE Spectrum Strategies and Forecasts to 2016

LTE Spectrum Strategies

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mHealth – Mobile Healthcare; consumer, doctors, healthcare providers, hardware and software tech enablers

The following is from a recent Mobile Internet SIG in the SV Forum.

You may want to get the presentations before listening to the video. Presentations available here.

4G Refarming Scenarios - Picture

Click on image to enlarge

From an old presentation of Qualcomm in the LTE World Summit 2010.

Self-Evolving Networks (SEN): Next step of SON

In a post last year, I listed the 3GPP features planned for the Self-Organising networks. Self-optimisation has been a part of the SON. It is becoming more of a common practice to refer to SON as Self-Optimising networks. A recent 4G Americas whitepaper was titled "Benefits of self-optimizing networks in LTE".

The next phase in the evolution of the Self-Configuring, Self-organizing and Self-optimizing network are the Self-Evolving Networks (aka. SEN) that will combine the Organizing and Optimizing features with the Self-testing and Self-Healing features. Self-testing and Self-healing have been recommended as subtasks of SON in the NGMN white paper. Self-testing and self-healing means that a system detects itself problems and mitigates or solves them avoiding user impact and significantly reducing maintenance costs.

We may still be a long way away from achieving this SEN as there are quite a few items being still standardised in 3GPP. Some of the standardised items have not yet been fully implemented and tested as well. Some of this new features that will help are listed as follows:

Automatic Radio Network Configuration Data Preparation (Rel-9)

When radio Network Elements (e.g. cells and/or eNBs) are inserted into an operational radio network, some network configuration parameters cannot be set before-hand because they have interdependencies with the configuration of operational NEs. "Dynamic Radio Network Configuration Data Preparation" comprises the generation and distribution of such interdependent parameters to the newly inserted network element and optionally already operational NEs.

This functionality allows fully automatic establishment of an eNB into a network. Otherwise an operator needs to set these configurations manually. Without this functionality self-configuration cannot be considered not fully as "self".

SON Self-healing management (Rel-10)

The target of Self-Healing (SH) is to recover from or mitigate errors in the network with a minimum of manual intervention from the operator.

Self-healing functionality will monitor and analyse relevant data like fault management data, alarms, notifications, and self-test results etc. and will automatically trigger or perform corrective actions on the affected network element(s) when necessary. This will significantly reduce manual interventions and replace them with automatically triggered re-s, re-configurations, or software reloads/upgrades thereby helping to reduce operating expense.

LTE Self Optimizing Networks (SON) enhancements (Rel-10)

This WI continues work started in Rel-9. Some cases that were considered in the initial phases of SON development are listed in the TR 36.902. From this list, almost all use cases are already specified. Capacity and Coverage Optimization (CCO) was already nominally part of the Rel-9 WI, but could not be completed due to amount of work related to other use cases. Energy Savings are a very important topic, especially for operators, as solutions derived for this use case can significantly limit their expenses. According to TR 36.902 this solution should concern switching off cells or whole base stations. This may require additional standardised methods, once there is need identified for.

Basic functionality of Mobility Load Balancing (MLB) and Mobility Robustness Optimization (MRO), also listed in TR 36.902, were defined in Rel-9. However, successful roll-out of the LTE network requires analysing possible enhancements to the Rel-9 solutions for MLB and MRO. In particular, enhancements that address inter-RAT scenarios and inter-RAT information exchange must be considered. These enhancements should be addressed in Rel-10. There may also be other use cases for LTE for which SON functionality would bring optimizations. The upcoming LTE-A brings about also new challenges that can be addressed by SON. However, since not all features are clearly defined yet, it is difficult to work on SON algorithms for them. It is therefore proposed to assign lower priority to the features specific for LTE-A.

UTRAN Self-Organizing Networks (SON) management (Rel-11)

For LTE, SON (Self-Organizing Networks) concept and many features have been discussed and standardised.

The SON target is to maintain network quality and performance with minimum manual intervention from the operator. Introducing SON functions into the UTRAN legacy is also very important for operators to minimize OPEX.

Automatic Neighbour Relation (ANR) function, specified in the LTE context, automates the discovery of neighbour relations. ANR can help the operators to avoid the burden of manual neighbour cell relations management.

Self-optimization functionalities will monitor and analyze performance measurements, notifications, and self-test results and will automatically trigger re-configuration actions on the affected network node(s) when necessary.

This will significantly reduce manual interventions and replace them with automatically triggered re-optimizations or re-configurations thereby helping to reduce operating expenses.

Minimization of Drive Tests (MDT) for E-UTRAN and UTRAN is an important topic in 3GPP Rel-10.

With the help of standardized UTRAN MDT solutions, Capacity and Coverage Optimization (CCO) for UTRAN should also be considered in UTRAN SON activities.

Study on IMS Evolution (Rel-11)

IMS network service availability largely relies on the reliability of network entity. If some critical network elements (e.g. S-CSCF, HSS) go out of service, service availability will be severely impacted. Moreover network elements are not fully utilized because network load is not usually well distributed, e.g. some nodes are often overloaded due to sudden traffic explosion, while others are under loaded to some extent. Though there’re some element level approaches to solve these problems, such as the ongoing work in CT4, the system level solution should be studied, for example, the method to distribute load between network elements in different regions especially when some disaster happens, such as earthquake.

The network expansion requires a great deal of manual configurations, and the network maintenance and upgrade are usually time-consuming and also costly for operators. Introducing self-organization features will improve the network intelligence and reduce the efforts of manual configuration. For example, upon discovering the entry point of the network, new nodes can join the network and auto-configure themselves without manual intervention. And if any node fails, other nodes will take over the traffic through the failed node timely and automatically.

The above mentioned features are just few ways in which we will achieve a truly zero-operational 4G network.

Radio-over-Fiber (RoF): The existing alternative to Femtocells

Recently while going through NTT Docomo Technical Journal, I came across an article on Radio over Fibre. This is the first time I have come across RoF but apparently this is a common way to provide indoor coverage before Femtocells.

My intention here is not to compare this with Femtocells as I can think of advantages and disadvantages of both of them.

I found the following extract in the book Femtocells: Technologies and Deployment:

Active Fibre DAS (Radio over Fibre)

Active fibre DAS is the most efficient in term of performance. Optical fibres are used to make the link between the MU and the RU. They can cover very long distances (up to 6 km) and support multiple radio services. With such a system the RU directly converts the optical signal into radio signal and vice versa. The other advantage is that optical fibre is very cheap and easy to install. Radio over fibre is now the most common technique used for indoor radio coverage. As detailed in [16], radio over fibre is today the optimal solution to extending indoor coverage, because it provides scalability, flexibility, easy expandability, and also because the signal degradation is very low compared with DAS using standard connections.

The following is from Wikipedia:

Radio over Fiber (RoF) refers to a technology whereby light is modulated by a radio signal and transmitted over an optical fiber link to facilitate wireless access. Although radio transmission over fiber is used for multiple purposes, such as in cable television (CATV) networks and in satellite base stations, the term RoF is usually applied when this is done for wireless access.

In RoF systems, wireless signals are transported in optical form between a central station and a set of base stations before being radiated through the air. Each base station is adapted to communicate over a radio link with at least one user's mobile station located within the radio range of said base station.

RoF transmission systems are usually classified into two main categories (RF-over-Fiber ; IF-over-Fiber) depending on the frequency range of the radio signal to be transported.

a) In RF-over-Fiber architecture, a data-carrying RF (Radio Frequency) signal with a high frequency (usually greater than 10 GHz) is imposed on a lightwave signal before being transported over the optical link. Therefore, wireless signals are optically distributed to base stations directly at high frequencies and converted to from optical to electrical domain at the base stations before being amplified and radiated by an antenna. As a result, no frequency up/down conversion is required at the various base station, thereby resulting in simple and rather cost-effective implementation is enabled at the base stations.

b) In IF-over-Fiber architecture, an IF (Intermediate Frequency) radio signal with a lower frequency (less than 10 GHz) is used for modulating light before being transported over the optical link. Therefore, wireless signals are transported at intermediate frequency over the optical.

Access to dead zones

An important application of RoF is its use to provide wireless coverage in the area where wireless backhaul link is not possible. These zones can be areas inside a structure such as a tunnel, areas behind buildings, Mountainous places or secluded areas such a jungle.

FTTA (Fiber to the Antenna)

By using an optical connection directly to the antenna, the equipment vendor can gain several advantages like low line losses, immunity to lightening strikes/electric discharges and reduced complexity of base station by attaching light weight Optical-to-Electrical (O/E) converter directly to antenna.

Weekend Humour: On Standards and Patents

Dilbert on STANDARDS

Another comic strip on Standards pointed out by Tor Bjorn Minde (@EricssonLabs)

Dilbert on PATENTS

TED talk: Wireless data from every light bulb

What if every light bulb in the world could also transmit data? At TEDGlobal, Harald Haas demonstrates, for the first time, a device that could do exactly that. By flickering the light from a single LED, a change too quick for the human eye to detect, he can transmit far more data than a cellular tower -- and do it in a way that's more efficient, secure and widespread.

See also :

LED-Fi: Replacement for WiFi Hotspots

Electromagnetic Radiation Spectrum charts.

Detailed presentation on Femtocell Security from Black Hat 2011

Femtocells: a Poisonous Needle in the Operator's Hay Stack

View more presentations from Zahid Ghadialy

Presentation available to download from here.

Detailed write-up on: Exploiting the Ubiquisys/SFR femtocell webserver here.

My earlier blogpost 'Femto Hacking in UMTS and LTE' here.

A look at "Idle state Signalling Reduction" (ISR)

The following is from 3GPP TS 23.401, Annex J:

General description of the ISR concept

Idle state Signalling Reduction (or ISR) aims at reducing the frequency of Tracking Area Updates (TAU, in EUtran) and Routing Area Updates (RAU, in UTRAN/GERAN) procedures caused by UEs reselecting between E-UTRAN and GERAN/UTRAN which are operated together. Especially the update signalling between UE and network is reduced. But also network internal signalling is reduced. To some extent the reduction of network internal signalling is also available when ISR is not used or not activated by the network.

UMTS described already RAs containing GERAN and UTRAN cells, which also reduces update signalling between UE and network. The combination of GERAN and UTRAN into the same RAs implies however common scaling, dimensioning and configuration for GERAN and UTRAN (e.g. same RA coverage, same SGSN service area, no GERAN or UTRAN only access control, same physical node for GERAN and UTRAN). As an advantage it does not require special network interface functionality for the purpose of update signalling reduction.

ISR enables signalling reduction with separate SGSN and MME and also with independent TAs and RAs. Thereby the interdependency is drastically minimized compared with the GERAN/UTRAN RAs. This comes however with ISR specific node and interface functionality. SGSN and MME may be implemented together, which reduces some interface functions but results also in some dependencies.

ISR support is mandatory for E-UTRAN UEs that support GERAN and/or UTRAN and optional for the network. ISR requires special functionality in both the UE and the network (i.e. in the SGSN, MME and Serving GW) to activate ISR for a UE. For this activation, the MME/SGSN detects whether S-GW supports ISR based on the configuration and activates ISR only if the S-GW supports the ISR. The network can decide for ISR activation individually for each UE. Gn/Gp SGSNs do not support ISR functionality. No specific HSS functionality is required to support ISR.

NOTE. A Release 7 HSS needs additional functionality to support the 'dual registration' of MME and SGSN. Without such an upgrade, at least PS domain MT Location Services and MT Short Messages are liable to fail.

It is inherent functionality of the MM procedures to enable ISR activation only when the UE is able to register via E-UTRAN and via GERAN/UTRAN. For example, when there is no E-UTRAN coverage there will be also no ISR activation. Once ISR is activated it remains active until one of the criteria for deactivation in the UE occurs, or until SGSN or MME indicate during an update procedure no more the activated ISR, i.e. the ISR status of the UE has to be refreshed with every update.

When ISR is activated this means the UE is registered with both MME and SGSN. Both the SGSN and the MME have a control connection with the Serving GW. MME and SGSN are both registered at HSS. The UE stores MM parameters from SGSN (e.g. P-TMSI and RA) and from MME (e.g. GUTI and TA(s)) and the UE stores session management (bearer) contexts that are common for E-UTRAN and GERAN/UTRAN accesses. In idle state the UE can reselect between E-UTRAN and GERAN/UTRAN (within the registered RA and TAs) without any need to perform TAU or RAU procedures with the network. SGSN and MME store each other's address when ISR is activated.

When ISR is activated and downlink data arrive, the Serving GW initiates paging processes on both SGSN and MME. In response to paging or for uplink data transfer the UE performs normal Service Request procedures on the currently camped-on RAT without any preceding update signalling (there are however existing scenarios that may require to perform a RAU procedure prior to the Service Request even with ISR is activated when GERAN/UTRAN RAs are used together, as specified in clause 6.13.1.3 of TS 23.060 [7]).

The UE and the network run independent periodic update timers for GERAN/UTRAN and for E-UTRAN. When the MME or SGSN do not receive periodic updates MME and SGSN may decide independently for implicit detach, which removes session management (bearer) contexts from the CN node performing the implicit detach and it removes also the related control connection from the Serving GW. Implicit detach by one CN node (either SGSN or MME) deactivates ISR in the network. It is deactivated in the UE when the UE cannot perform periodic updates in time. When ISR is activated and a periodic updating timer expires the UE starts a Deactivate ISR timer. When this timer expires and the UE was not able to perform the required update procedure the UE deactivates ISR.

Part of the ISR functionality is also available when ISR is not activated because the MM contexts are stored in UE, MME and SGSN also when ISR is not active. This results in some reduced network signalling, which is not available for Gn/Gp SGSNs. These SGSNs cannot handle MM and session management contexts separately. Therefore all contexts on Gn/Gp SGSNs are deleted when the UE changes to an MME. The MME can keep their MME contexts in all scenarios.

Note:

Gn = IP Based interface between SGSN and other SGSNs and (internal) GGSNs. DNS also shares this interface. Uses the GTP Protocol.

Gp = IP based interface between internal SGSN and external GGSNs. Between the SGSN and the external GGSN, there is the border gateway (which is essentially a firewall). Also uses the GTP Protocol.

"Temporary Identity used in Next update" (TIN)

The UE may have valid MM parameters both from MME and from SGSN. The "Temporary Identity used in Next update" (TIN) is a parameter of the UE's MM context, which identifies the UE identity to be indicated in the next RAU Request or TAU Request message. The TIN also identifies the status of ISR activation in the UE.

The TIN can take one of the three values, "P-TMSI", "GUTI" or "RAT-related TMSI". The UE sets the TIN when receiving an Attach Accept, a TAU Accept or RAU Accept message as specified in table 4.3.5.6-1.

"ISR Activated" indicated by the RAU/TAU Accept message but the UE not setting the TIN to "RAT-related TMSI" is a special situation. By maintaining the old TIN value the UE remembers to use the RAT TMSI indicated by the TIN when updating with the CN node of the other RAT.

Only if the TIN is set to "RAT-related TMSI" ISR behaviour is enabled for the UE, i.e. the UE can change between all registered areas and RATs without any update signalling and it listens for paging on the RAT it is camped on. If the TIN is set to "RAT-related TMSI", the UE's P-TMSI and RAI as well as its GUTI and TAI(s) remain registered with the network and valid in the UE.

When ISR is not active the TIN is always set to the temporary ID belonging to the currently used RAT. This guarantees that always the most recent context data are used, which means during inter-RAT changes there is always context transfer from the CN node serving the last used RAT. The UE identities, old GUTI IE and additional GUTI IE, indicated in the next TAU Request message, and old P-TMSI IE and additional P-TMSI/RAI IE, indicated in the next RAU Request message depend on the setting of TIN.

The UE indicates also information elements "additional GUTI" or "additional P-TMSI" in the Attach Request, TAU or RAU Request. These information elements permit the MME/SGSN to find the already existing UE contexts in the new MME or SGSN, when the "old GUTI" or "old P-TMSI" indicate values that are mapped from other identities.

ISR activation

The information flow in Figure below shows an example of ISR activation. For explanatory purposes the figure is simplified to show the MM parts only.

The process starts with an ordinary Attach procedure not requiring any special functionality for support of ISR. The Attach however deletes any existing old ISR state information stored in the UE. With the Attach request message, the UE sets its TIN to "GUTI". After attach with MME, the UE may perform any interactions via E-UTRAN without changing the ISR state. ISR remains deactivated. One or more bearer contexts are activated on MME, Serving GW and PDN GW, which is not shown in the figure.

The first time the UE reselects GERAN or UTRAN it initiates a Routing Area Update. This represents an occasion to activate ISR. The TIN indicates "GUTI" so the UE indicates a P-TMSI mapped from a GUTI in the RAU Request. The SGSN gets contexts from MME. When the MME sends the context to the SGSN, the MME includes the ISR supported indication only if the involved S-GW supports the ISR. After the ISR activated, both CN nodes keep these contexts because ISR is being activated. The SGSN establishes a control relation with the Serving GW, which is active in parallel to the control connection between MME and Serving GW (not shown in figure). The RAU Accept indicates ISR activation to the UE. The UE keeps GUTI and P-TMSI as registered, which the UE memorises by setting the TIN to "RAT-related TMSI". The MME and the SGSN are registered in parallel with the HSS.

After ISR activation, the UE may reselect between E-UTRAN and UTRAN/GERAN without any need for updating the network as long as the UE does not move out of the RA/TA(s) registered with the network.

The network is not required to activate ISR during a RAU or TAU. The network may activate ISR at any RAU or TAU that involves the context transfer between an SGSN and an MME. The RAU procedure for this is shown in Figure above. ISR activation for a UE, which is already attached to GERAN/UTRAN, with a TAU procedure from E-UTRAN works in a very similar way.

Reference: 3GPP TS 23.401: General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access

Cellphone radiation and Cancer

There is an interesting graph in Scientific American (Via Bill Gross on Google+) showing the radiation spectrum of Cell phones and other devices. Click on the image to view full size.

Thing to note: As the graphic above shows, the radiation emitted in this region is nonionizing: it may heat molecules in the body but does not ionize them (that is, set electrons free). Ionizing radiation, which can tear molecules apart and therefore potentially damage DNA—is the greater worry.

In the comments of the discussion, someone pointed out this hand drawn Electromagnetic Spectrum which is very handy.

Click to enlarge

Finally, it is worthwhile checking out the total radiation that we can encounter in different events and their relative values.

Click to enlarge.

Wi-Fi in Public Transport over LTE

Another interesting presentation from the LTE World Summit 2011 on how LTE can be used as a backhaul in the trains to provide passenger WiFi and other services.

Uses for LTE in the Transport Vertical Market

View more presentations from Zahid Ghadialy

Human Activity Recognition for Personalised services

Human Activity Recognition for Personalised Services

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Interesting article from the NTT Docomo Technical journal.

How many radios are there in my phone?

Click to enlarge

From a presentation by John Haine of Cognovo in the Future of Wireless International Conference 2011.

MRO: Handover failures signalling

Continuing on the Self-organising Network (SON) feature of Mobility Robust Optimisation, Handover failures.

Click on image to enlarge

One of the discussions I had with a colleague is how would the signalling happen in case of Handover failures I mentioned earlier.

After the handover failure, when the connection is successfully established again either as a normal Setup or Re-Establishment or RRC Reconfiguration then a new optional field is available:

rlf-InfoAvailable-r10 ENUMERATED {true} OPTIONAL,

This is used to indicate to the network that the UE has some information relating to the RL Failure that occurred.

The network will then use the UE Information Request I blogged about earlier to ask for this information. The UE will send the information back in the response.

It should be noted that this UEInformationRequest and Response messages were introduced part of Release-9 but there has been since some updates in Release-10. The Response message now looks as follows:

RLF-Report-r9 ::= SEQUENCE {

measResultLastServCell-r9 SEQUENCE {

rsrpResult-r9 RSRP-Range,

rsrqResult-r9 RSRQ-Range OPTIONAL

},

measResultNeighCells-r9 SEQUENCE {

measResultListEUTRA-r9 MeasResultList2EUTRA-r9 OPTIONAL,

measResultListUTRA-r9 MeasResultList2UTRA-r9 OPTIONAL,

measResultListGERAN-r9 MeasResultListGERAN OPTIONAL,

measResultsCDMA2000-r9 MeasResultList2CDMA2000-r9 OPTIONAL

} OPTIONAL,

...,

[[ locationInfo-r10 LocationInfo-r10 OPTIONAL,

failedPCellId-r10 CHOICE {

cellGlobalId-r10 CellGlobalIdEUTRA,

pci-arfcn-r10 SEQUENCE {

physCellId-r10 PhysCellId,

carrierFreq-r10 ARFCN-ValueEUTRA

}

} OPTIONAL,

reestablishmentCellId-r10 CellGlobalIdEUTRA OPTIONAL,

timeConnFailure-r10 INTEGER (0..1023) OPTIONAL,

connectionFailureType-r10 ENUMERATED {rlf, hof} OPTIONAL,

previousPCellId-r10 CellGlobalIdEUTRA OPTIONAL

]]

}

Everything after the extension marker ellipses (...) is added in release 10. More information in Release-10 RRC specs (36.331)

Outline of GCF Certification Process

Click on Image to enlarge

From a presentation by Colin Hamling, Vice Chair, GCF Steering Group in LTE World Summit, Amsterdam, 18 May 2011

Femto Hacking in UMTS and LTE

Couple of weeks back, The Hacker’s Choice (THC) made available some documents about how the Vodafone's (UK) Femtocell (a.k.a. SureSignal) is unsecure and can be hacked. Everyone seemed to jump on this bandwagon with some news articles even sounding like the whole Vodafone network has been hacked and hackers may be sending messages and making calls via your phone number.

In the end it came to light that the problem was fixed over a year back when Vodafone was made aware of this problem. THC is still arguing that there is an architecture fault and the Femto can be compromised.

As a result I decided to think about what could happen if the Femtocell is hacked.

Lets take case of UMTS Femtocell. A simple network architecture with femtocell (oficially known as Home NodeB) is as follows:

As you can see, the signalling over the air interface is encrypted and integrity protected. If a hacker is able to get into the Femto and able to listen to all the packets using some tool like WireShark, he would be able to get hold of the Ciphering and Integrity Keys as they come in cleartext in the RANAP Security Mode Command message.

It wouldnt be difficult to have a device that can listen to the conversations once provided with this keys. In fact if the hacker is able to listen to the messages, there is no reason he cannot stick his own messages at the right interval (when a voice call is ongoing) to send SMS and would appear that the message actually went from the phone number. Note that this message would be inserted in the Home NodeB and would be a NAS message. The end user would generally never find out that a message has been sent on behalf of his phone.

One thing that should be remembered though is that the phone would have to be in the range of the Femtocell and connected successfully to the network (via the Femto). One question someone may have is that can I not reverse engineer the key so that I can clone the SIM card. Fortunately for us, this is not easily possible. There are multiple levels of protection and generally it would be difficult to get the algorithms for generating the key. Also it should be noted that the authentication algorithms are confidential and only the operators know the algorithm.

Now lets look at the LTE Femtocell (a.k.a. Home eNodeB) as shown below:

One of the differences you may notice is that the signalling from Femto to the Core Network over S1 is encrypted and Integrity Protected. In case of the LTE Femto, there are multiple keys and only the required key (Kenb) is provided to the Femto. See the key hierarchy below:

Source: RedYoda

This would sound like an ideal protection from the end user perspective but some of the problems still remain. If the hacker can get hold of the Kenb which is sent in cleartext over the S1 interface via Initial Context Setup Request message then he could easily use it to listen to the packets. Since there is no voice support as of yet in LTE, it would only be the packets that the hacker can listen to.

As you may notice, there is now an Integrity and Ciphering on the S1 interface for the UE messages, the hacker cannot get hold of the Kasme or the master keys K, CK and IK. This means that he cannot insert rouge messages that would for example send unsolicited SMS on behalf of the user as he would be able to do in case of UMTS.

There is a small caveat though. There are multiple Ciphering and Integrity algorithms defined in the standard. No ciphering is defined as eea0 algorithm. In Release-8 of LTE, there was no possibility to have Integrity switched off as there was no eia0 algorithm defined. In Release-9 though, the new eia0 has been defined which means that the network can set the Integrity to NULL. I am sure that the network would not want to do so as it makes absolutely no sense but the hacker can force it to do so.

When the Network requests the UE to send the capability information, the hacker can force it to say that it only supports eia0 and eea0 which would mean that the integrity and ciphering in the call would be off. To be honest, this is quite a difficult thing to do in real time and also the network would not accept a UE that does not support other Integrity and Ciphering algorithms.

3GPP has already forseen these kind of threats that could be affecting the networks in the future when they roll out the Femtocells. As a result they have produced 3GPP TR 33.820 that lists all the possible threats and the best practices that can help to minimise the chances of the network being compromised. If that document is too big and technical, you can go though this presentation as it summarises some of the problems.

Feel free to comment or correct any mistakes that you think I have made.

Benefits of Self Optimizing Networks in LTE

Self Optimizing Networks : Benefits of SON in LTE - July 2011

View more documents from Zahid Ghadialy

Mobility Robustness Optimization to avoid Handover failures

The following is from 4G Americas Whitepaper on SON:

Mobility Robustness Optimization (MRO) encompasses the automated optimization of parameters affecting active mode and idle mode handovers to ensure good end-user quality and performance, while considering possible competing interactions with other SON features such as, automatic neighbor relation and load balancing.

There is also some potential for interaction with Cell Outage Compensation and Energy Savings as these could also potentially adjust the handover boundaries in a way that conflicts with MRO. While the goal of MRO is the same regardless of radio technology namely, the optimization of end-user performance and system capacity, the specific algorithms and parameters vary with technology.

The objective of MRO is to dynamically improve the network performance of HO (Handovers) in order to provide improved end-user experience as well as increased network capacity. This is done by automatically adapting cell parameters to adjust handover boundaries based on feedback of performance indicators. Typically, the objective is to eliminate Radio Link Failures and reduce unnecessary handovers. Automation of MRO minimizes human intervention in the network management and optimization tasks.

The scope of mobility robustness optimization as described here assumes a well-designed network with overlapping RF coverage of neighboring sites. The optimization of handover parameters by system operators typically involves either focused drive-testing, detailed system log collection and postprocessing, or a combination of these manual and intensive tasks. Incorrect HO parameter settings can negatively affect user experience and waste network resources by causing HO ping-pongs, HO failures and Radio Link Failures (RLF). While HO failures that do not lead to RLFs are often recoverable and invisible to the user, RLFs caused by incorrect HO parameter settings have a combined impact on user experience and network resources. Therefore, the main objective of mobility robustness optimization should be the reduction of the number of HO-related radio link failures. Additionally, sub-optimal configuration of HO parameters may lead to degradation of service performance, even if it does not result in RLFs. One example is the incorrect setting of HO hysteresis, which may results in ping-pongs or excessively delayed handovers to a target cell. Therefore, the secondary objective of MRO is the reduction of the inefficient use of network resources due to unnecessary or missed handovers.

Most problems associated with HO failures or sub-optimal system performance can ultimately be categorized, as either too-early or too-late triggering of the handover, provided that the required fundamental network RF coverage exists. Thus, poor HO-related performance can generally be categorized by the following events:

* Intra-RAT late HO triggering

* Intra-RAT early HO triggering

* Intra-RAT HO to an incorrect cell

* Inter-RAT too late HO

* Inter RAT unnecessary HO

Up to Release 9, a UE is required to send RLF report only in case of successful RRC re-establishment after a connection failure. Release 10 allows support for RLF reports to be sent even when the RRC reestablishment does not succeed. The UE is required to report additional information to assist the eNB in determining if the problem is coverage related (no strong neighbors) or handover problems (too early, too late or wrong cell). Furthermore, Release 10 allows for precise detection of too early / wrong cell HO.

Smart Deployment with Smart Antennas and ORI

This is from a presentation by Dr. Peter Meissner, Operating Officer, NGMN Alliance.

Its very interesting the way the Antennas are evolving.

If you are interested in reading more about ORI, see the earlier post here.

NSN Celebrating 20 years of GSM

Its been 20 years since the first GSM call was made and GSM is still as relevant today as it was 10 years back.My earlier post today was about the technology deployment and adoption trends and my guess is that GSM/GPRS will be still relevant for long time to come especially its de-facto fallback for the roaming calls. Some Facts about GSM that would should know:* First network launched in 1991* There are 838 GSM Networks in 234 countries with 4.4 Billion subscribers* In 2010, 1.44 million GSM subscribers were added every day* 545 EDGE networks in 198 countries with 1.5 Billion subscribers* By 2015, 1.5billion GSM M2M subscribers will be present

Here is a presentation from NSN about 20 years of GSM and since they had the privilege of launching the first commercial network I am sure they have a good reason to celebrate.

20 Years of GSM: Past, Present & Future

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A new section on 3G4G website on GSM has been added here.

Technology Deployment and Adoption Trends

This informative slide shows the number of years it takes after the technology is launched to reach the peak volumes. Though we know this to be true for the 1G and 2G systems, I find it difficult to believe the same would be true for 3G and 4G systems.

If the LTE deployments are going to happen as per the plans then we may see the peak volumes for 3G/HSPA+ around 2016. It would be difficult to predict the same for '4G' systems as we do not know as of know what all would be part of 4G. As you would recall that LTE was supposed to be 3.9G but was too confusing so everyone adopted it as 4G. LTE-A, the real 4G, I guess would still be part of 4G. What else would end up as 4G is hard to predict so we will have to go with the prediction for the time being.

Dual-Mode and Multi-Mode Femtocells

Came across this slide in one of the presentations from MWC.

The Dual-Mode and maybe Multi-Mode solution (in future) may be very useful, not only from the point of view that it can serve LTE as well as 3G mobile devices but in case of a LTE mobile where for voice calls the UE may have to fall back on 3G network, if there is no 3G coverage then there would be no voice communication possible.

One of the ways to do have a voice communication in the initial phases of LTE is CS Fallback (CSFB). CSFB is possible by the UE establishing the call on UMTS or GSM network. If for some reason the coverage on those networks is non-existent then having a dual-mode femtocell can be really helpful as it would seamlessly transfer the voice call on the 3G.

Hopefully in the future when VoLTE is here these problems would be solved automatically.

The main problem that I can see with this Dual-mode or Multi-mode solution is that the operator would have to be supporting both Small Cells solution across both the networks and I guess they would be slightly expensive.

Infographic on 'The Internet of Things'

Very interesting Infographic from Cisco on the 'Internet of Things' that we have discussed before.

Since its not possible for me to put the whole Infographic here, you can check it out on Cisco blogs.

A Survey on 3GPP Hetrogeneous Networks

A Survey on 3GPP Hetrogeneous Networks

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Available for limited time to download free from here.

Network Mode of Operation (NMO)

Picture Source: Tektronix

The Network Mode of Operation (NMO) is also sometimes referred to as Network Operation Mode (NOM). The Network Modes have different values and interpretation in UTRAN and GERAN

In both the cases the Operation modes is decided based on the Gs interface between the CS CN (core network) a.k.a. MSC and the PS CN a.k.a. SGSN

In UTRAN:

Network Operation Mode I (NMO-I) is used when the Gs interface is present. In this case during the registration a Combined Attach (includes GPRS Attach & IMSI Attach procedures) procedure can be performed. A GMM Attach Request message with the attach type set to Combined Attach is used. Upon completion of this procedure, MM Status is IMSI Attached and GMM State is Attached.

In Network Operation Mode II (NMO-II) the GS Interface is not present. So the GMM attach procedure and the IMSI Attach (via Location Update) has to be performed seperately. This causes additional signalling.

Basic air interface signalling in case of NMO2 is shown here.

In GERAN:

Network operation mode 1. A network which has the Gs interface implemented is referred to as being in network operation mode 1. CS and PS paging is coordinated in this mode of operation on either the GPRS or the GSM paging channel. If the mobile device has been assigned a data traffic channel then CS paging will take place over this data channel rather than the paging channel (CS or PS).

Network operation mode 2. The Gs interface is not present and there is no GPRS paging channel present. In this case, paging for CS and PS devices will be transferred over the standard GSM common control channel (CCCH) paging channel. Even if the mobile device has been assigned a packet data channel, CS paging will continue to take place over the CCCH paging channel and thus monitoring of this channel is still required.

Network operation mode 3. The Gs interface is not present. CS paging will be transferred over the CCCH paging channel. PS paging will be transferred over the packet CCCH (PCCCH) paging channel, if it exists in the cell. In this case the mobile device needs to monitor both the paging channels.

The GERAN part above is extract from the book Convergence Technologies for 3G Networks.

From Martin Sauter's Blog:

The Gs interface, has a number of subtle but important advantages:

During an ongoing GPRS / EDGE data transfer (TBF established), mobiles can't detect incoming voice calls and SMS messages as they are focused on receiving packets and thus can not observe the paging channel. In NMO-1, the circuit switched part of the network forwards the paging message to the packet switched side of the network which then forwards the paging message between the user data blocks while a data transfer is ongoing. Mobiles can thus receive the paging message despite the ongoing data transfer, interrupt the session and accept the voice call or SMS.

Location/Routing area updates when moving to a cell in a different location/routing area are performed much faster as the mobile only communicates with the packet switched part of the network. The packet switched network (the SGSN) then forwards the location update to the circuit switched part of the network (to the MSC) which spares the mobile from doing it itself. This is especially important for ongoing data transfers as these are interrupted for a shorter period of time.

Cell reselections from UMTS to GPRS can be executed much faster due to the same effect as described in the previous bullet. Whithout NOM-1 an Inter RAT (Radio Access Technology) cell reselection with Location and Routing Area update requires around 10 to 12 seconds. With NOM-1 the time is reduced to around 5 to 6 seconds. An important difference as this reduces the chance to miss an incoming call during the change of the radio network. Also, ongoing data transfers are interrupted for a shorter time,an additional benefit that should not be underestimated.

HSPA evolution – beyond 3GPP Release 10

HSPA evolution – beyond 3GPP Release 10, Ericsson, Jul. 2011

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This and other HSPA/HSPA+ presentations are available to download here.

Couple of presentations on GNSS and LCS

I came across couple of presentations from International Conference on Localization and GNSS, held in Tampere, Finland, June 29-30, 2011

This first presentation by Lauri Wirola of Nokia gives good summary of standardized positioning technologies in use today. It also lists the difference between control plane and user plane positioning. The 3GPP based positioning from Rel 5 to Rel 8 has been listed. Overall a very interesting presentation.

Location Standards driving the mass market LCS adoption

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The second presentation by Ignacio Fernández Hernández of the European Commission, gives an overview of the EU satnav programmes (Galileo, EGNOS) and current R&D status; Present some numbers and findings of the overall GNSS R&D panorama in EU and abroad; Present some trends and challenges in location technologies for the following years. Another interesting presentation I think.

GNSS Programmes and R&D landscape in the EU

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Mobile Telephony in Rural India

Another presentation from The Future of Wireless International Conference:

Mobile Telephony in Rural India

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Nitin Dahad has a special report on similar topic in India Inc. You can read the article here.

Antenna height and coverage

From a presentation by Ed Candy of '3' in FWIC.

Self explanatory.

Couple of presentations on Backhaul

The Key to Successful Backhaul

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Future mobile backhaul considerations

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Revenues vs Network Investments

Nice Pic summarising the Network investments vs Revenue for Voice and Data. Click on Pic to enlarge.

A quick TD-­‐LTE Update - Markets & technology: May 2011

Another presentation from LTE World Summit.May 2011: A quick TD-­‐LTE Update - Markets & technology

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Dilbert takes a snipe at Smartphones

Interesting theme from couple of Dilbert's this week.

Related post: Mobile Phone Antennas and Networks

Summary of 'The Future of Wireless International Conference' #fwic

Here is a summary of the Future of Wireless International conference held in Cambridge on the 27th and 28th of June 2011. The summary is a compilation of my notes with the tweets sent using the #FWIC tag.

DAY 1

Roberto di Pietro, VP Product Marketing and Business Development, Qualcomm CDMA Technologies

• 26 million 3G connections being added every month

• 226% growth is seen in smartphones from 2010 - 2014

• Mobile as a single platform for developers.

• Devices smart enough to know which network to connect to

• Qualcomm arrived on the scene 6 months after everyone but they are the only ones with 4G, 3G and 2G multi-mode chips

• In 2012 they would be releasing the new System Architecture with Single / Dual / Quad cores upto 2.5GHz (Snapdragon next gen)

• Question: Will smartphones die in the future when people move to tablets for everything except for voice/sms and they get simpler phones for that

• Answer: Smartphones will co-exist as companion devices with the tablets and will continue growing for a while.

• In other discussions: QoS will be a big differentiator and offloading would certainly be needed. Femtocells are going to form part of any strategy.

• Network signaling load and need for developers to improve apps design noted in qualcomm keynote here in cambridge

Mr. BongGoon Kwak, Senior Vice President, The head of Mobile Business Fast Incubation Business Department Mobile Business Group in Korea Telecom.

• KT adding 0.5 million users every month.

• Mobile data predicted to grow 26 fold by 2015 (6.2 exabytes/month)

• E = MC^2. Where E = evolution, M = mobile and C = connectivity

• mobile banking users in Korea increased 100% to 18 million due to smartphones

• smartphone ARPU up 32% on feature phone

• KakaoTalk (http://www.kakao.com/talk/en) users have increased which has in turn reduced the SMS ARPU

• NaaS (Network as a Service) is a new trend

Mr. Edward Zhou, CMO of Western European Region, Huawei Technologies Co. Ltd.

• states they have 5300 people in Europe but only 65% are from local market

• No. 2 telecom solution provider with revenues of $28 billion

• has 110,000+ employees with 150 nationalities worldwide, more than half work in R&D

• By 2020 there will be 5.5B MBB (Mobile Broadband) users as opposed to 1.5B FBB (Fixed Broadband)

• 70% of companies (especially SMEs) will be using cloud based services.

Mr. R. Swaminathan, Senior Executive Vice President, Reliance Communications Ltd.

• Low cost mobile networks and devices helped drive innovation in low cost business models in Rural India

• Customisation is a mecessity for the rural market.

• One offering includes a fixed phone that uses Mobile as a backhual using the Yagi antenna

• 15 operators in rural India. Voice tariff went from 20cents to 1 cent. Entry cost reduced by 95%

• ARPU in rural India is $2.

• Telecom operators have done innovations to keep costs to minimum

• Phone to tablet is best evolution for Indian rural market, using visual images and txt to speech technologies not smartphones

• Good to have some text to voice and vice-versa apps

• Ends with saying that there are 870 million people in rural India and possible market size is $25 billion that can be exploited

Kanwar Chadha, Chief Marketing Officer and Board Member of Cambridge Silicon Radio

• Innovations in location-aware wire-free connected world

• Spoke on view of local business vs global, very entertaining perspective , assume nothing and be careful of interpretation

• Example is the initial GPS cost $3700 but was still successful in Japan because guys wanted to show it off to their dates.

• Maslow's hierarchy of needs dont work for India as its more important to have entertainment (TV) than roof.

• FM very succesful in India but nowhere else.

• Sat Navs will not succeed in India because addresses and maps not very well mapped. Things like coupons, sms will be very successful

Innovation Hothouse: Mr. Christian Leicher, Member of the Executive Board at Rohde & Schwarz GmbH & Co. KG.

Session on start-ups very interesting

• Augmentra talked of GPS based smartphone apps. Users can share and get paid when someone else download what they share. Their guidebooks, etc are trusted by half the search and rescue mountain teams

• Oxems have a solution for the new plastic pipes that are being deployed. The normal metal detectors cant detect these pipes so they have a RFID based solution.

• Pneumacare has a non-contact medicare solution that can be used to track people with respiratory problems

• MagicSolver.com has a unique app discovery solution that can reach upto 6 millions users in 90 different countries.

• Cambridge temperature concepts has a solution that can increase the chances of fertility without IVF to the same levels after 6 months use.

Interesting points from the breakout sessions:

• Mike Bowerman of Alcatel-Lucent: Soon we will see pricing based on time of day, location, etc. Infrastructure sharing lower costs but it means that coverage from some location can completely vanish.

• John frieslaar of Huawei talks about how many will be connected to networks and the cause of demand

• Stephen temple says industry must spur innovation not gov.agree but will gov let us?

• 75% of UK mobile data consumption is driven by BBC iplayer, YouTube and adult videos says Sam Leinhardt of Penthera

• Ed Candy, 3: Apps evolving from Handset Apps to Widgets to Intelligent Browsers based

• Content is king but context is queen

• O2 in UK started putting data caps and lost 7K customers in London. They were using 7% of network capacity so O2 happy to get rid of them

DAY 2

Stephen Baily, General Manager, BBC R&D

• BBC R&D iPlayer usage on tablets is 3million/mth 2% of total

• Dual screens being explored by BBC with a universal controller API. The proposal has been submitted to W3C.

• Working on Dual-Screen concept where iPad becomes a complimentary device to TV (See http://www.pocket-lint.com/news/40584/bbc-focused-ipad-dual-screen)

• BBC R&D iPlayer usage on tablets is 3million/mth 2% of total

• BBC is looking again at mobile broadcasting based on DVB-t2m standard

• 90% of broadcast os normal schedule than the time shifted one.

Dr. Tapani Ryhänen, Laboratory Director, heading Eurolab (Cambridge and Lausanne) of Nokia Research Centre

• Imagining tomorrow devices, creating technology today

• Morph concept video

• Nokia Research Center in Cambridge working in lots of futuristic technologies like Data driven Apps, Stretchable electronics, Bend to zoom, flexible phone and display

• Another video that I wasnt able to locate on Youtube

Few points from The "Can big wireless deliver on the promise of a big society?" Panel Debate

• Motorola's David Chater-Lea: "Due to spectrum needs we're going to see breakdown of barriers between commercial & private networks"

• Neul/Ofcom's William Webb: "To get a truely wireless society we need more small cells and increased backhaul. Then we need FTTH"

• Otherwise we're going to have situation where wireless will be held back by the wired network

• Public safety: should governments use private networks or commercial networks & give priority to emergency services over customers?

Graham Fisher, Former CEO of Orange Labs R&D, BathCube:

• Net neutrality doesn't work in a world of finite resources

• High end phones expectaions include screens that can work in sunlight, AR, 3D, etc.

• When it comes to retail price plans mobile operators are all in a bargain basement, they need to reintroduce value

Dan Reed, Corporate Vice President, Technology Policy and Strategy and eXtreme Computing Group at Microsoft

• The uber change happening is collision of computing/comms/content. We need to work out how to work together

Ken Blakeslee, Chairman of WebMobility Ventures:

• Digital natives vs digital immigrants

• Is mobile too inward looking?

• We're moving from hardware to software driven marketplace where communities are the new currency

• Users can be bought and bribed, communities can not

Interesting Obervation:

• Cambridge Wireless - run largely by women as an organisation but 95% of attendees at Future of Wireless conf #fwic are male

Poll of #fwic audience returns 50:50 re: whether mobile infrastructure should be common wholesale solution vs competitive between operators

Hopefully you have enjoyed this summary!