3GPP Femtocells: Architecture and Protocols
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Wednesday, May 11, 2011
Tuesday, May 10, 2011
Advanced IP Interconnection of Services (IPXS) in 3GPP Rel-11
The following is edited from the 3GPP documents:
IP is being introduced in both fixed and mobile networks as a more cost-effective alternative to circuit switched technology in the legacy PSTN/PLMN, as well as the underpinning transport for delivering IMS based multi-media services.
In order to ensure carrier grade end to end performance, appropriate interconnect solutions are required to support communications between users connected to different networks. There are currently a number of initiatives underway outside 3GPP addressing IP Interconnection of services scenarios and commercial models to achieve this; for example, the GSM Association has developed the IPX (IP Packet Exchange). Also, ETSI has recently defined requirements and use case scenarios for IP Interconnection of services. These initiatives require the use of appropriate technical solutions and corresponding technical standards, some of which are already available and others which will require development in 3GPP.
Moreover, new models of interconnection may emerge in the market where Network Operators expose network capabilities to 3rd party Application Providers including user plane connectivity for the media related to the service.
The main objective of IPXS is thus:
To specify the technical requirements for carrier grade inter-operator IP Interconnection of Services for the support of Multimedia services provided by IMS and for legacy voice PTSN/PLMN services transported over IP infrastructure (e.g. VoIP).
These technical requirements should cover the new interconnect models developed by GSMA (i.e. the IPX interconnect model) and take into account interconnect models between national operators (including transit functionality) and peering based business trunking.
Any new requirements identified should not overlap with requirements already defined by other bodies (e.g. GSMA, ETSI TISPAN). Specifically the work will cover:
• Service level aspects for direct IP inter-connection between Operators, service level aspects for national transit IP interconnect and service level aspects for next generation corporate network IP interconnect (peer-to-peer business trunking).
• Service layer aspects for interconnection of voice services (e.g. toll-free, premium rate and emergency calls).
• Service level aspects for IP Interconnection (service control and user plane aspects) between Operators and 3rd party Application Providers.
To ensure that requirements are identified for the Stage 2 & 3 work to identify relevant existing specifications, initiate enhancements and the development of the new specifications as necessary.
II-NNI in the 3GPP standard
View more presentations from Zahid Ghadialy
European Commission conducted a study on this topic back in 2008 and produced a lengthy report on this. Since the report is 187 pages long, you can also read the executive summary to learn about the direction in technical, economic and public policy.
Sunday, May 8, 2011
What is '4G' ?
One of the most popular posts is Dilbert's definition of '4G'. So I decided to go back and see how and if the definition of '4G' has changed over the time.
And finally my '4G' FAQ from 2006 that is seriously outdated and needs updating :)
Back in 2008, '4G' was more of WiMAX. Here is a video from that time:
2009 video of Cisco where they are pushing for 4G = IP :
2010 video that says 4G = fast :
And finally my '4G' FAQ from 2006 that is seriously outdated and needs updating :)
Thursday, May 5, 2011
4G and Wi-Fi Change The Wireless Game
Towerstream 4 gwe presentation final (1)
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Presented on Feb. 2, 2011 by Jeff Thompson, CEO, Towerstream in 4G Wireless Evolution Conference in Miami, Fl.
Wednesday, May 4, 2011
New Security Algorithms in Release-11
I did mention in my earlier blog post about the new algorithm for 3GPP LTE-A Security. The good news is that this would be out hopefully in time for the Release-11.
The following from 3GPP Docs:
The current 3GPP specifications for LTE/SAE security support a flexible algorithm negotiation mechanism. There could be sixteen algorithms at most to support LTE/SAE confidentiality and integrity protection. In current phase, 3GPP defines that there are two algorithms used in EPS security, i.e. SNOW 3G and AES. The remaining values have been reserved for future use. So it is technically feasible for supporting new algorithm for LTE/SAE ciphering and integrity protection.
Different nations will have different policies for algorithm usage of communication system. The current defined EPS algorithm may not be used in some nations according to strict policies which depend on nation’s security laws. Meanwhile, operators shall implement their networks depending on national communication policies. To introduce a new algorithm for EPS security will give operators more alternatives to decide in order to obey national requirements.
Picture: Zu Chongzi
Picture Source: Wikipedia
Some work has been done to adapt LTE security to national requirements about cryptography of LTE/SAE system, i.e. designing a new algorithm of EPS security, which is named ZUC (i.e. Zu Chongzhi, a famous Chinese scientist name in history). Certainly the new algorithm should be fundamentally different from SNOW 3G and AES, so that an attack on one algorithm is very unlikely to translate into an attack on the other.
The objective of this work item is to standardise a new algorithm in EPS. This will include the following tasks:
• To develop new algorithms for confidentiality and integrity protection for E-UTRAN
• To enable operators to quickly start to support the new algorithm
• Not to introduce any obstacle for R8 roaming UE
The following issues should at least be handled in the WI:
• Agree requirement specification with ETSI SAGE for development of new algorithms
• Delivery of algorithm specification, test data and design and evaluation reports
The algorithm is provided for 3GPP usage on royalty-free basis.
The algorithm shall undergo a sequential three-stage evaluation process involving first ETSI SAGE, then selected teams of cryptanalysts from academia and finally the general public.
The documents related to the EEA3 and EIA3 algorithm could be downloaded from here.
If you are new to LTE Security, the following can be used as starting point: http://www.3g4g.co.uk/Lte/LTE_Security_WP_0907_Agilent.pdf
Friday, April 29, 2011
Service Layer Optimization element to Improve Utilisation of Network Capacity
Picture Source: Simple LTE for 4G Mobile Broadband
The following is an extract from 4G Americas whitepaper, "Optimizing the Mobile Application Ecosystem":
Applications have diverse requirements on the mobile network in terms of throughput, relative use of uplink vs. downlink, latency and variability of usage over time. While the underlying IP based Layer 3 infrastructure attempts to meet the needs of all the applications, significant network capacity is lost to inefficient use of the available resources. This inefficiency stems primarily from the non-deterministic nature of the aggregate requirements on the network from the numerous applications and their traffic flows live at any time.
This reduction in network utilization can be mitigated by incorporating application awareness into network traffic management through use of Application or Service Layer optimization technologies. A Service Layer optimization solution would incorporate awareness of:
1) device capabilities such as screen size and resolution;
2) user characteristics such as billing rates and user location;
3) network capabilities such as historic and instantaneous performance and;
4) application characteristics such as the use of specific video codecs and protocols by an application such as Video on Demand (VOD) to ensure better management of network resources.
Examples of Service Layer optimization technologies include:
* Real-time transcoding of video traffic to avoid downlink network congestion and ensure better Quality of Experience (QoE) through avoidance of buffering
* Shaping of self-adapting traffic such as Adaptive Streaming traffic through packet delay to avoid downlink network congestion
* Shaping of error-compensating flows such as video conferencing through use of packet drops to avoid uplink network congestion
* Shaping of large flows such as file uploads on the uplink through packet delays to conserve responsiveness of interactive applications such as web browsing
* Explicit caching of frequently accessed content such as video files on in-network CDNs to minimize traffic to backbone
* Implicit caching of frequently accessed content such as images in web content on in-network caches to improve web page retrieval speeds
Service Layer optimization technologies may be incorporated in the data path in many locations:
1) the origin server;
2) the UE device;
3) as a cloud-hosted offering through which devices and/or applications and/or networks route traffic or;
4) as a network element embedded in a service provider’s network.
Further, in a service provider’s network the optimization function may be deployed in either the core network and/or edge aggregation locations. When Service Layer optimization entities in the network are deployed at both core and edge locations, they may operate in conjunction with each other to form a hierarchy with adequate level of processing to match the traffic volume and topology. Such a hierarchy of network entities is especially effective in the case of caching.
The 3GPP standard network architecture defines a number of elements such as QoS levels that are understood and implemented in the network infrastructure. However, much of this network capability is not known or packaged for use in the Service Layer by application developers. One approach to resolving this discrepancy may be to publish standard Service Layer APIs that enable application developers to request network resources with specific capabilities and also to get real-time feedback on the capabilities of network resources that are in use by the applications. Such APIs may be exposed by the network to the cloud or may be exposed to application clients resident on mobile devices through device application platforms and SDKs. The network APIs being defined by the Wholesale Application Community are an example of the recognition of the need for such Service Layer visibility into network capabilities. Future versions of the WAC standards will likely incorporate and expose network Quality of Service (QoS) capabilities.
Pic Source: Aria Networks
Why does Optimization matter? A good answer to this question is provided in Telecoms.com article as follows:
For many people, says Constantine Polychronopoulos, founder and chief technology officer of mobile internet infrastructure specialist Bytemobile, the definition of optimisation as it relates to mobile networks is too narrow; restricted to compressing data or to the tweaking of the radio access network in a bid to improve throughput. While these are key elements of optimisation, he says, the term ought to be interpreted far more broadly. “The best way for us to think of optimisation,” he says, “is as a set of synergistic technologies that come together to address everything that has to do with improving network and spectrum utilisation and user experience. If you stretch the argument, it includes pretty much every thing that matters. This holistic, end-to-end approach to optimisation is the hallmark of Bytemobile’s solutions. Point products tend to be costly and difficult or impossible to evolve and maintain.”
And optimisation matters, he says, because the boom in mobile data traffic experienced in some of the world’s most advanced mobile markets represents a serious threat to carrier performance and customer satisfaction. US operator and pioneer iPhone partner AT&T is a case in point, Polychronopoulos says.
“If you look at what’s been said by Ralph de la Vega (president and CEO of AT&T Mobility) and John Donovan (the firm’s CTO), they have seen a 5,000- per cent increase in data traffic over the past two years. The data points from other operators are similar,” he continues. “They see an exponential growth of data traffic with the introduction of smartphones, in particular the iPhone.”
Operators may have received what they’d been wishing for but the scale of the uptake has taken them by surprise, Polychronopoulos says. The type of usage consumers are exhibiting can be problematic as well. Bytemobile is seeing a great deal of video-based usage, which can often be a greater drain on network resource than web browsing. Given the increasing popularity of embedding video content within web pages, the problem is becoming exacerbated.
Dr. Polychronopoulos is keen to point out that there are optimisation opportunities across different layers of the OSI stack—Bytemobile offers solutions that will have an impact on layers three (the IP layer) through seven (the application layer). But he stresses that some of the most effective returns from optimisation technologies come from addressing the application layer, where the bulk of the data is to be found.
“An IP packet can be up to 1,500 bytes long,” he says. “So at layer three, while you can balance packet by packet, there is only so much you can do to optimise 1,500 bytes. At the top layer, the application can be multiple megabytes or gigabytes if you’re watching video. And when you’re dealing with those file sizes in the application layer, there is a whole lot more you can do to reduce the amount of data or apply innovative delivery algorithms to make the content more efficient,” he says.
By optimising content such as video, Polychronopoulos says, significant gains can be made in spectral and backhaul network utilisation. A range of options are open to operators, he says, with some techniques focused on optimising the transport protocol, and others designed to reduce the size of the content.
“With video, we can resize the frame, we can reduce the number of frames, we can reduce the resolution of the frame or apply a combination of the above in a way that does not affect the video quality but greatly improves network efficiencies,” he says. “So if you go to a site like YouTube and browse a video, you might download something like 100MB of data. But if you were to go through a platform like ours, you may download only 50MB when the network is congested and still experience not only the same video quality, but also fluid video playback without constant re-buffering stalls.”
It is possible, he explains, to run these solutions in a dynamic way such that data reduction engages only when the network is congested. If a user seeks to access high-volume data like video during the network’s quiet time, the reduction technologies are not applied. But when things are busier, they kick in automatically and gradually. This could have an application in tiered pricing strategies. Operators are looking at such options in a bid to better balance the cost of provisioning mobile data services with the limited revenue stream that they currently generate because of the flat rate tariffs that were used to stimulate the market in the first place. Being able to dynamically alter data reduction and therefore speed of delivery depending on network load could be a useful tool to operators looking to charge premium prices for higher quality of service, Polychronopoulos says.
If it is possible to reduce video traf- fic in such a way that data loads are halved but the end user experience does not suffer proportionally, the question arises as to why operators would not simply reduce everything, whether the network was busy or not. Polychronopoulos argues that in quiet times there are no savings to be made by reducing the size of content being transported.
“The operator has already provisioned the network one way or another,” he says, “so there is a certain amount of bandwidth and a certain amount of backhaul capacity. When the network is not congested, the transport cost is already sunk. When it becomes congested, though, you get dropped calls and buffering and stalled videos and the user experience suffers. That’s where optimisation shines. Alternatively, media optimisation can be factored in during toplevel network provisioning when the savings in CAPEX can be extremely compelling.”
While LTE is held up by some within the industry as the panacea to growing demand for more mobile broadband service, Polychronopoulos is unconvinced. If anything, he says, the arrival of the fourth generation will serve only to exacerbate the situation.
“LTE is going to make this problem far more pronounced, for a number of reasons,” he says. “As soon as you offer improved wireless broadband, you open the door to new applications and services. People are always able to come up with new ways of inundating any resource, including bandwidth. We’re going to see more data-driven applications on mobile than we see on the typical desktop, because the mobile device is always with you.” And while LTE promises greater spectral efficiency than its 3G forebears, Polychronopoulos says, the fact that spectrum remains a finite resource will prove ever more problematic as services evolve.
“We’re reaching the limits of spectral efficiency,” he says. “Shannon’s Law defines the limit as six bits per Hertz, and while we may be moving to higher-bandwidth wireless broadband, spectrum remains finite. To offer 160Mbps, you have to allocate twice the amount of spectrum than in 3G, and it’s a very scarce and very expensive resource.”
Operators have been wrong to focus exclusively on standards-based solutions to network optimisation issues, Polychronopoulos says. In restricting themselves to 3GPP-based solutions, he argues that they have missed what he describes as “the internet component of wireless data.” Internet powerhouses like Google, Yahoo and Microsoft (which he dubs ‘the GYM consortium’) have established a model that he says is a great threat to the mobile operator community in that it establishes a direct consumer relationship and disregards the “pipe” (wireless broadband connection) used to maintain that relationship.
“The operators have to accelerate the way they define their models around wireless data so that they’re not only faster than the GYM consortium in terms of enabling popular applications, but smarter and more efficient as well,” he says. Dr. Polychronopoulos then makes a popular case for the carriers’ success: “The operators have information about the subscriber that no other entity in the internet environment can have; for example, they know everything the subscriber has done over the lifetime of their subscription and the location of each event. They don’t have to let this data outside of their networks, so they are very well positioned to win the race for the mobile internet.”
Wednesday, April 27, 2011
Possible Release-12 features
Not sure if everyone checked the presentation from yesterday, it has a slide that lists possible Rel-12 features that I have listed below:Release 12 content not yet defined, but Study Items (SI) in Release 11 indicate where specification work is likely
•Study on IMS based Peer-to-Peer Content Distribution Services
•Study on IMS based Peer-to-Peer Content Distribution Services (Stage 2)
•Study on IMS Network-Independent Public User Identities
•Study on Integration of Single Sign-On (SSO) frameworks with 3GPP networks
•Study on Coordinated Multi-Point operation for LTE
•Study on UE Application Layer Data Throughput Performance
•Study on Uplink MIMO
•Study on Non Voice Emergency Services
•Study on UICC/USIM enhancements
•Study on Alternatives to E.164 for Machine-Type Communications
•Study on enhancements for Machine-Type Communications (MTC)
•Study on Support for 3GPP Voice Interworking with Enterprise IP-PBX
•Study on Security aspects of Integration of Single Sign-On (SSO) frameworks with 3GPP networks
•Study on Core Network Overload solutions
•Study on Continuity of Data Sessions to Local Networks
•Study on Non-MTC Mobile Data Applications impacts
•Study on System Enhancements for Energy Efficiency
•Study on Solutions for GSM/EDGE BTS Energy Saving
•Study on HSDPA Multipoint Transmission
•Study on Inclusion of RF Pattern Matching as a positioning method in the E-UTRAN
Release 11 completion date set for September 2012, Release-12 work will start after that.
Tuesday, April 26, 2011
3GPP Standards Update for FemtoZone during MWC 2011
From the Mobile World Congress, not so long back.
3GPP Standards Update - Adrian Scrase (16/02/2011) from ETSI – World Class Standards on Vimeo.
The presentation is embedded below:
Monday, April 25, 2011
Advanced Telephony Services for LTE
With LTE World Summit just round the corner, I was going through the last year's presentations and realised that we didn't talk of this one before.
The concept for the advanced telephony services has been around since the early days of IMS and this was one of the ways IMS was sold. Unfortunately IMS didn't take off as planned and only now with the standardisation of VoLTE, there is a possibility of the advanced services becoming a reality.
The following presentation summarises some of these advanced telephony services concepts.
Sunday, April 24, 2011
ANDSF: Access Network Discovery and Selection Function
The following is a recent news from Mobile Europe:
For more details see:
WeFi has launched a product that is intended to enable mobile operators to route traffic over the mobile macro network or a WiFi hotspot without the consumer having to manage their own settings.
The product, from WeFi, enables operators to set network management policies using a 3GPP-defined function for the Evolved Packet Core called ANDSF – Access Network Discovery and Selection Function. WeFi said that its WeANDSF is the first standards-compliant product on the market, although it said that as the standards are not yet fully finalised, the product is more accurately described as a pre-standards compliant product.
ANDSF, specified in 3GPP standards 23.402 and 24.312, is intended to allow mobile operators to set network management policies and priorities, and to control where, when and under what circumstances a subscriber’s device connects to which wireless network, be it cellular or Wi-Fi.
Operators may choose to route traffic according to application type to reduce network load, or to provide the best available customer experience. Although operators are increasingly looking at using WiFi for offload in congested areas, one problem for them is that once traffic is routed over WiFi control is lost over any traffic policies they have set for that user. ANDSF keeps a link to the operator's core network, allowing the operator visibility of traffic even when it is routed over WiFi.
WeFi said that the product is already in trials with several mobile operators. As handset manufacturers are yet to include the device element of ANDSF, WeFi is also providing a device client, although it sees that role diminishing as handset vendors deliver ANDSF-compliant handsets, “when these become available in the market by 2012”.
The following presentation is by Fraunhofer Fokus on ANDSF: Access Network Discovery and Selection in the Future Broadband Wireless Environment
View more presentations from Zahid Ghadialy
For more details see:
3GPP TS 23.402: Architecture enhancements for non-3GPP accesses
3GPP TS 24.312: Access Network Discovery and Selection Function (ANDSF) Management Object (MO)
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