Tuesday, January 12, 2010

LTE -- What Voice Services?

by Jose Deras, Vice President, Sales Engineering

Much has been written lately about increased bandwidth benefits of LTE and Communication Service Providers (CSPs) plans to deploy the technology as the 4G foundation. Many CSPs have announced their LTE plans, some have begun LTE data trials, and the first LTE commercial data service was launched in December in Scandinavia. For sure there's a coming wave of network upgrades and new handsets that will certainly transform mobile broadband.

CSPs considering the transition to LTE data are faced with the decision of whether to also offer LTE voice services in order to better utilize the new network infrastructure, or deploy LTE data-only networks. For the most part, it seems that the desire is there to transition to LTE voice sooner rather than later. This strategy makes sense as LTE requires entirely new radio access technology, from antennas to base station controller upgrades, and keeping two radio access networks greatly increases OPEX which might be best spread across a wider segment of offerings.

It is the ‘how' to deliver LTE voice services that has created confusion. When LTE was originally envisioned, the conventional thinking was that the CSP's networks would have transitioned to IMS architectures by then and therefore voice on LTE would naturally be based on VoIP. The reality is that as of this writing, there are very few true IMS production networks in place and therefore CSPs must reconcile how to quickly deploy LTE with the realities of network transformation timelines and budgets.

Options, options

Of course there are options on how to move forward with voice delivery architectures. The backdrop of which is the general agreement that current 2G and 3G networks will be in place for some time to come, and therefore CSPs must take into account not only how their network will evolve, but how to support roaming and handovers across multiple CSPs. In addition, the expectation is that current 2G / 3G subscribers will be the first to migrate to 4G as CSPs provide upgrade incentives, which puts additional burden of providing feature and service parity as part the upgrade as subscribers will expect their current call feature sets to behave the same once they upgrade.
Among the most studied options for voice delivery are:
• 3GPP IMS. The obvious long term solution for voice delivery is based on a migration to the IMS, leveraging industry know-how gained as part of the development of UMTS. Deployment of IMS-based LTE voice has been documented since IMS Release 8 and it's viewed as the preferred long term solution for voice evolution. Moving to IMS has the obvious advantage of commoditizing a large portion of the network, bringing with it all the benefits discussed for several years now.

 3GPP Circuit Switched FallBack. In addition to IMS, 3GPP has also proposed using a technique called Circuit Switched FallBack (CSFB), whereby the handset normally operates in 4G (LTE) mode when accessing data services and idle, but switches to a 2G or 3G radio when it is informed of an incoming call, or an outgoing call is placed, or for circuit-switched applications such as SMS. The handsets therefore are dual-mode, supporting 2/3G for voice and 4G for data services. A mechanism to inform the handset via 4G (IP data path) that a call is inbound does need to be formalized, and there is some concern regarding longer call setup times instigated by the necessity of switching radios.

 Voice over LTE Generic Access. Another option that has been put forth is Voice over LTE Generic Access (VoLGA), supported by a newly-formed industry consortium known as the VoLGA Forum. VoLGA proposes utilizing the IMS-based LTE radio access network, but maintains the circuit-switched network (either GSM or CDMA based) by introducing a network element known as the VANC (VoLGA Access Network Controller).

 Proprietary Solutions. Other options do exist, such as upgradable IP-enabled MSCs, but those tend to be tied to a specific vendor architecture and may be best approached by current customers.
To be clear, these architecture options address how to marry the packet-switched LTE radio network with the service operator core network for the purpose of delivering voice. What is not immediately apparent is how does the CSP deliver voice applications, such as Find Me / Follow Me, Voice VPN, CRBT and all the critical revenue generating add-ons that subscribers use and would expect to migrate to LTE.

Service Brokering

Regardless of the architecture chosen, CSPs will be faced with application delivery challenges created by the transition in LTE to packet based voice. Today's voice services are predominantly delivered via Service Control Points (SCP) or Intelligent Network (IN) Application Servers that rely on IN protocols (such as INAP and CAMEL) for complex call control. Those services tend to be highly stable and profitable and also highly customized, and are therefore not easily moved to SIP-based application servers. Recreating the functionality of deployed IN-based applications requires a exhaustive survey, documentation, and duplication of used features and capabilities, a task that may not be easily achieved. CSPs will need to deliver these same services (down to feature sets and even quirky behavior) on LTE subscribers to ensure migrated users have the same level of service and experience.
As CSPs evolve their networks for LTE, the resulting networks present tremendous challenges in voice services and application delivery. It's the same challenge faced in migrations to NGN and IMS. Realizing this opportunity, the telecom software industry has come forward with a purpose-built network element: the Service Broker, a solution specifically designed to overcome network architecture challenges and ensure voice service delivery from any network domain to any other network domain.

Service Brokers are placed between the application layer and the control layer, with the purpose of delivering and extending the reach of applications to all network domains of the CSP. They do this by performing the signaling, media and call control interworking between the applications and different network domains. Implicit in the successful deployment of service brokers is the capability of delivering the required interworking without necessitating changes to either the applications or the networks. The risk of "breaking something" in the migration of the applications is removed by not touching or modifying existing code.
Let's take a look at how Service Broker might fit within two of the most popular network proposals, IMS and VoLGA.

LTE Voice over IMS

Service Brokers provide the capability of extending current voice services by providing seamless call / session interworking between the packet switched LTE access network, and circuit-switched 3G applications without requiring changes to either. For those CSPs that have fixed line networks as well, they are also able to reutilize voice services which may have been only offered in that network domain to new wireless LTE subscribers.

In the figure above, LTE clients are able to access all applications they previously used, such as PrePaid, CRBT, Voice VPN, Find Me / Follow Me, etc, and therefore are not required to change their subscribed services. From a network perspective, the Service Broker enables the IMS network to "see" the existing applications as new SIP-based applications, by providing the interworking required. As far as the IMS network is concerned, the Service Broker is the SIP server, while to the existing SCPs the Service Broker is an existing 3G MSC.

LTE via Circuit Switched FallBack

For those service providers deploying CSFB, the 2G/3G network remains unchanged so existing applications will work unchanged on LTE. Service brokers are therefore not required for those applications but may instead be useful to prepare the core network for the eventual migration towards IMS. New IMS-based application servers can be utilized on the 2G/3G circuit switched networks, ensuring all new application deployments are based on the IMS architecture.

When ready, the service provider may then migrate to LTE over IMS using their IMS based application servers. Service brokers remain in place to provide connectivity for older applications, and to perform service orchestration and sequencing, thereby extending their useful life.

LTE Voice over VoLGA

Those CSPs that choose to follow an architecture based on the VoLGA forum proposals, the Service Broker provides as similar benefit as with CSFB, allowing next-gen SIP-based applications to be utilized by the existing 3G network.

Service Broker Functions

Service Brokers provide other functionality that, once deployed, can be of added benefit to the CSP. Among the most often delivered features are:
• IMS SCIM (now renamed the IMS Service Broker)
• IN-IN Trigger Management
• Real-Time Charging
• Protocol/Call Flow Management
• Subscriber Data Management Interaction
• Media Resource Brokering
• Service Orchestration
The Service Broker's ability of performing orchestration and combination of discrete voice applications and services into new combined offerings (voice mash-ups) is particularly exciting. With this capability CSPs are able of create new revenue producing offers to subscribers where they previously were not available: CRBT and PrePaid, Find Me / Follow Me combined with Voice VPNs, etc.

Service Brokers also provide the capability of generating Real Time Charging events, either programmatically (via an API) or automatically as part of service delivery. The challenge facing CPSs is delivering new, innovative services that seamlessly integrate into existing billing platforms. Doing so often means normalizing charging events or even transforming charging events from one technology to another, as is the case in IN to IMS migration. Because the Service Broker is responsible for orchestrating and delivering combinational services, it is often then the responsibility of the Service Broker to generate a charging event upon successful start / completion of those enhanced services.


CSPs are currently spending a lot of time and energy qualifying LTE radio access network technology, which will ensure live deployments maintain or exceed current mobile reliability. The next several quarters will prove interesting as CSPs choose LTE voice delivery architectures, much of it influenced by time and their own network designs requirements. Careful consideration of voice services and applications will ensure high-value customers (early LTE adopters) are able to enjoy the same voice features and services they are currently used to, ensuring they are permanent converts. Service Brokers will play a critical role in ensuring CSPs are able to immediately migrate current voice revenue platforms for those early LTE subscribers.

About the Author

Jose Deras is Vice President, Sales Engineering at AppTrigger, where he handles technical sales engagements. Prior to AppTrigger he was VP Sales Engineering for Siemens Communications, responsible for the global technical sales and support for the broadband equipment segment. At Siemens (which acquired startup Efficient Networks), Jose also held positions of VP Product Line Management and Director of Technical Marketing and Business Development. Prior to Efficient Networks, Jose held several roles in sales and sales engineering at Compaq Computer and Networth Inc., a startup in Dallas, TX that Compaq acquired in 1995.

The Service Broker Forum

The Service Broker Forum is a multi-vendor association with the goal of evangelizing and educating the telecommunication industry on the service broker product category through the sharing of ideas, opinions, and knowledge. Founded by industry leaders in the Service Broker market space, the forum provides a common platform to facilitate discussion and communication around the many benefits that can be realized from utilizing Service Brokers within an overall network evolution strategy. Learn more about it at

HP and Microsoft Chase Cloud Infrastructure-to-Application Model

HP and Microsoft announced a three-year agreement to pursue a new integrated technology stack that would significantly simplify technology environments for businesses. The companies will collaborate on an engineering roadmap for data management machines; converged, prepackaged application solutions; comprehensive virtualization offerings; and integrated management tools.

Specifically, HP and Microsoft plan to deliver new solutions that will:

  • be built on a next-generation infrastructure-to-application model;

  • advance cloud computing by speeding application implementation; and

  • eliminate complexities of IT management and automate existing manual processes to lower the overall costs.

The new infrastructure-to-application model from HP and Microsoft will be delivered as integrated offerings for large, heterogeneous data center environments as well as through solutions designed for small and midsize businesses.

Nintendo's Wii to Stream Netflix

Nintendo's Wii will begin supporting online movie streaming from Netflix in the U.S. starting this spring. Netflix memberships start at $8.99 a month and offer unlimited streaming of movies and TV shows.

As of Sept. 30, 2009, Netflix had 11.1 million subscribers. Streaming service is already available for Microsoft's Xbox 360 and Sony's PlayStation 3.

To enable their systems to stream content from Netflix, Wii owners will need a Netflix instant-streaming disc for the Wii console, which will be available at no additional cost to Netflix subscribers.

GSMA: 2.6 GHz Band Vital for the Growth of LTE

The licensing of the 2.6 GHz band will be critical to unlocking the benefits of global scale economies in the Mobile Broadband market, according to a new report* by US-based research firm Global View Partners in partnership with the GSMA. The research found that the 2.6 GHz spectrum, which has been identified globally by the ITU as the "3G extension band", will be vital in satisfying the demand for greater capacity for mobile broadband.

The report provides and update on the current status of worldwide licensing of the 2.6 GHz spectrum band and assesses the viability and implications of the three ITU band plan options.

The 2.6 GHz band (2500-2690 MHz), sometimes also referred as the 2.5 GHz band, was allocated by the World Radiocommunication Conference (WRC) in 2000 for terrestrial mobile communications services. The report notes that to date, the 2.6 GHz band is unique in that the band includes a substantial amount of spectrum (190 MHz) that has been allocated on a primary basis in all three ITU regions for terrestrial mobile communications. Still, controversy exists surrounding the extent to which and how the 190 MHz available in the 2.6 GHz band plan should be divided between paired and unpaired spectrum suited to FDD and TDD modes of operation respectively. The International Telecommunications Union (ITU) presents three possible options:

  • Option 1 - Preconfigured allocations of paired (FDD) and unpaired (TDD) spectrum.

  • Option 2 - Paired spectrum only with the uplink portion of some pairs in another undetermined band.

  • Option 3 -- Flexibility, allowing the bidders for spectrum to decide how they want to allocate the spectrum they acquire to paired (FDD) or unpaired (TDD) operation.

Licenses have been issued in several countries to-date, notably Norway, Sweden, Finland, Singapore, Hong Kong, and the United States, and more 2.6 GHz auctions are anticipated over the next one to two years in multiple national markets.

In Europe, measurable progress has been achieved towards the allocation of the 2.6 GHz frequency, as specified in the ITU Option 1 plan. There is widespread agreement at the member state and European Union level that this objective will best be fulfilled in a manner that is harmonised and coordinated across all countries in the region. The research suggests that leaving the band unstructured for auctions or with a diverse mix of non-harmonised FDD and TDD allocations should be avoided. Potential challenges include interference management, resulting reductions in usable bandwidth and loss of coverage in border regions, as well as higher costs and delayed equipment availability.

The full report is online.

Ohio's Wabash Mutual Telephone Deploys Occam

Wabash Mutual Telephone, a subscriber-owned operator serving an 82-square mile area in West Central Ohio, is deploying Occam Networks 'FTTP equipment in new areas within and beyond its existing footprint.

Wabash Mutual deployed Occam's ADSL2Plus solutions in 2005 as part of its Triple Play strategy. Today all of Wabash Mutual's ILEC service area enjoys ADSL2Plus service. Wabash Mutual is currently completing a competitive FTTH overbuild with Occam equipment that will include a series of 10 Gigabit middle mile transport rings feeding Gigabit Ethernet FTTH access nodes. The first of these rings already provides network connectivity to broadband subscribers in rural communities.

Motorola Enables DOCSIS 3.0 for Armstrong Cable

Armstrong Cable is deploying the Motorola BSR 64000 TX32 Decoupled Downstream Module across its broadband network to enable DOCSIS 3.0 capabilities. By adding high-density and redundant TX32 modules directly into the Motorola BSR 64000, Armstrong can deliver an additional 64 QAM channels out of an existing chassis.

Armstrong operates cable systems in Kentucky, Maryland, New York, Pennsylvania, Ohio, and West Virginia.

BT Gains IP Management Patent

BT's Diamond IP division, which develops software, appliances and services for managing IP networks, has been awarded a U.S. patent for its "Internet Protocol Address Management System and Method."

This patent describes an IP Address Management (IPAM) system which supports both IPv4 and IPv6 address space using a unique hierarchical container structure and block allocation techniques. The structure and techniques have been implemented in BT Diamond IP products, initially in the NetControl product and in its successor, IPControl.

JDSU Enhances Triple-Play Service Quality Test Suite

JDSU announced a triple-play service quality test suite for itsHST-3000 Handheld Services Tester and T-BERD/MTS-4000 Multiple Services Test Platform.

Specifically, the JDSU Class of Service (CoS) test suite enables the simultaneous testing of multiple services running over multiple VLANs at the same time. During the test, technicians are able to view all of the services in use but also a graphical depiction of bandwidth across all of them.

JDSU said this helps the technician identify and resolve environments where one service may be impacting the performance of another. The new features also enable on/off control of all services - from one screen. The technician is therefore able to do exactly what the customer may be doing, offering an ideal test/traffic simulation and troubleshooting environment.

NSN Supplies Core Network for Canada's SaskTel

SaskTel, a full service communications provider in Saskatchewan, has selected Nokia Siemens Networks to provide core network technology for a new next-generation wireless network. Specifically, NSN will supply mobile softswitching, packet core with "direct tunnel" functionality, and harmonized subscriber management systems. The upgraded systems will complement SaskTel's existing 3G network and provide a transition to 4G/LTE. SaskTel's network is expected to be initially launched mid-2010 with a targeted completion date of 2011. Financial terms were not disclosed.

TeliaSonera Selects Ericsson and NSN for 4G/LTE

TeliaSonera, which is the first carrier in the world to launch commercial LTE service, announced that its common 4G/LTE core network will be delivered exclusively by Ericsson and the radio networks by Ericsson and Nokia Siemens Networks. Financial terms were not disclosed.

On 14-December-2009, TeliaSonera launched 4G services to customers in Stockholm, Sweden and Oslo, Norway. TeliaSonera was also the first operator to make a live 4G connection in Finland.

TeliaSonera's current 4G networks cover the central city areas of Stockholm and Oslo. The 4G network roll-out will continue to Sweden's 25 largest municipalities and recreation areas and to Norway's four largest municipalities to offer communication services for the future.

In December, Ericsson confirmed that it had provided TeliaSonera with LTE Radio Base stations, an Evolved Packet Core network, a mobile backhaul solution including SmartEdge 1200 routers, the latest EDA multi-access aggregation switch and an Operation and Management System. Separately, Huawei stated that it had delivered both network infrastructure and services, including access network gear, core network equipment, operation support systems, and network planning and optimization.

However, TeliaSonera now says that Huawei will only finalize the 4G city network in Oslo.

Nokia Siemens Network now confirms that it has won a two-year agreement to provide LTE radio equipment, LTE network management systems, and LTE multi-vendor integration and care services to TeliaSonera. Nokia Siemens Networks will supply its Single RAN solution with its Flexi Multiradio base stations, as well as its NetAct network management system to monitor, manage and optimize the network. The company will also provide multi-vendor integration and care services.

"The use of mobile broadband in the Nordic countries is exploding and customers need higher speeds and capacity. Both Ericsson and Nokia Siemens Networks have been able to provide high quality technology and competitive offers," says Lars Klasson, Senior Vice President and CTO, Mobility Services, TeliaSonera.

Mobile Giving Foundation Enables SMS Donations to Haiti

The Mobile Giving Foundation, a non-profit organization based in Washington state, set-up an SMS-based micro-donation system in the U.S. and Canada. Donations of $5 or $10 can be made to various charities providing relief to victims of the earthquake in Haiti. 100% of your donation goes to the recipient charity, and the donation appears as a charge on your carrier bill, standard texting rates may apply.

There are several organizations that are responding to this urgent need with mobile‑giving efforts, including the following:

Text the word "Yele" to 501501 to donate $5

On behalf of the Yéle Foundation, the leading contributor to rebuilding Haiti founded by Wyclef Jean

Text the word "Haiti" to 85944 to donate $5

On behalf of the Rescue Union Mission and MedCorp International

Text the word "Haiti" to 25383 to donate $5

On behalf of the Internal Rescue Committee

Text the word "Haiti" to 90999 to donate $10

On behalf of the Red Cross in the U.S.

Text the word "Haiti" to 45678 (In Canada Only)

On behalf of the Salvation Army in Canadahttp://www.mobilegiving.org/http://

Télécoms Sans Frontières Dispatches to Haiti

Télécoms Sans Frontières (TSF), which provides emergency telecoms support in partnership with the U.N. and other groups, has dispatched a team equipped with Inmarsat mobile voice and broadband terminals to Haiti. Further reinforcements will shortly leave from TSF's international headquarters in France.

Haiti's cellular and terrestrial telecoms network appear to be damaged beyond use. Satellite communications now provide the only means for communicating to, and within, the country.

The TSF teams will use Inmarsat BGAN and Mini-M to provide essential communications services -- a critical requirement for co-ordinating the early stages of the response -- for the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), the European Commission's Humanitarian Aid Department (ECHO), and other NGOs arriving to assist with relief efforts.

After the initial emergency response, TSF will offer communications for the local population, enabling them to call family and loved ones. TSF estimates that up to 5.4 million people could be affected by the humanitarian catastrophe.