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Home Invasion: Femtocells

By: Richard "Zippy" Grigonis

For cell phone users who deplore the quality of their wireless service when making a phone call in their home, a solution is now appearing – the femtocell. Basically an amazingly small home 3G cellular radio base station that uses your broadband service as an inexpensive backhaul scheme to link to the mobile core network, femtocells can bring Fixed-Mobile Convergence (FMC) to the home or small business (or even a big one, for that matter), competing with WiFi hotspots.

Femtocell (News - Alert) users not only enjoy a high level of voice quality, but many network operators and service providers are attempting to achieve service parity among fixed networks, and femtocells. Femtocell customers will soon have handsets capable of not just voice and SMS, but various familiar data and entertainment services such as IPTV (News - Alert), Unstructured Supplementary Service Data (USSD) services, remote access to PC content, Caller ID, call forwarding, 3-way calling, call blocking and regulatory services (e.g., E911 and CALEA-compliant wire tapping). The millions of potential femtocells out there will encourage many users to finally abandon their fixed, wireline phones in favor of a totally mobile technology-based lifestyle. ABI Research (News - Alert) predicts 102 million femtocell users on 32 million access points worldwide by 2011.

Femtocells have garnered enthusiasm in Europe, with initial FMC services appearing from BT and France Telecom, powered by equipment from both major vendors such as Ericsson and Motorola (News - Alert) as well as smaller start-ups as UbiquiSys, whose flagship product is their 3G HSDPA ZoneGate home access point system, and IP.access, which has deals with such network operators as Smart in the Philippines, Telefonica O2 in the Czech Republic, T-Mobile (News - Alert) USA, and KPN (formerly Telfort) in the Netherlands.

There are two basic approaches to providing femtocells — the advanced SIP/IMS (Session Initiation Protocol/IP Multimedia Subsystem (News - Alert))-based approach and the IP RAN (Radio Access Network) Gateway approach, which can take advantage of legacy equipment, as it makes the femtocell an extension into the operator’s wireless network and connects the femtocell to the circuit switch core from the edge of the network via “Iub” messages over IP into an RNC (Radio Network Controller) or concentrator. (The RNC uses an Iub interface to control multiple Node Bs in a 3G network.)

There are at least three RAN gateway approaches: First, the Modified RNC scheme uses RNCs to connect to the circuit-switched core network. The CPE connects via Iub-over-IP to the RNC. Second, the Concentrator scheme also connects similarly to core, but it does so via a special “concentrator” device interfacing with the customer presence equipment. Finally, the UMA (Unlicensed Mobile Access) approach integrates a UMA client into the customer equipment and connects via a UMA UNC to the core. This is the closest thing to a completed standard, with Kineto finishing it in 2008.

Indeed, Kineto Wireless (News - Alert) was the original innovator and proponent of UMA technology, a 3GPP standard for extending mobile voice, data and IMS services over fixed IP access networks. Their Fixed-Mobile Convergence (News - Alert) solutions include dual-mode handsets, femtocells, terminal adaptors and softmobiles at home, offices and public wireless LANs. They are a leading supplier of UMA-compliant core network solutions to operators worldwide, and they supply UMA-compliant client software solutions to mobile device manufacturers.

Steve Shaw (News - Alert), Associate Vice President of Marketing at Kineto, says, “Right now there’s a sort of ‘femto-frenzy’ in the market. People are just going crazy for femtocells, but how its it all going to play out? Will femtocells meet customer needs? Will we be able to get the costs down to a level that people expect? And where does WiFi (News - Alert) fit into all of this?”

“From a Kineto Wireless/UMA perspective,” says Shaw, “we’re feeling very bullish about femotcells. We’re in a great position to be a part of several network deployments. There has been a slew of interesting announcements lately. For example, O2 announced a trial with NEC (News - Alert), which is using Kineto’s UMA technology in their femtocell solution. Also, Telia announced a trial with Motorola, which also uses Kineto’s UMA technology.”

“There has been quite a bit of talk about standardization in the femtocell space,” says Shaw. “Recently the Femto Forum issued an announcement saying that their primary work item for 2008 was going to be on standardization of femtocells back into the mobile core network. There’s the SIP/IMS-based approach wherein the SIP protocol is used between the mobile core network and the femtocells. And then there’s a RAN [Radio Access Network] gateway approach based on a new, purpose-built network controller – the RAN Gateway (News - Alert) – that resides between an operator’s existing core service network and the IP access network, similar to an RNC. The RAN gateway uses the standard “Iu” core network protocol to leverage the existing MSC (News - Alert) circuit services and GSN packet services infrastructure. Our UMA technology is a RAN gateway approach. By leveraging the legacy Iu interface into the mobile core, any circuit, packet or IMS service can be delivered seamlessly to the femtocell. For the network operator, all services can be presented to subscribers when in a femtocell network. For consumers, any service operating on the macro RAN network functions identically over a femtocell access point.”

Alcatel has their own approach to femtocells, as does Nokia (News - Alert) Siemens. These all extremely similar in terms of architecture and we’re now working down at the level of ‘What’s the format of the message?’ and ‘What exactly is being exchanged between devices?’ Our pitch at Kineto is, ‘Hey, UMA is already available, why not use that?’.”

Just as there are several IP RAN gateway approaches, there are several different SIP-based approaches. There’s an IETF approach, a 3GPP approach, and so on. All of them involve integrating a femtocell into a SIP or IMS-based Voice-over-IP network, and interworking with a cellular core (which extends circuit-switched services to the handset) via a SIP-MSC inter-working function (SIP-MSC IWF). This approach is highly scalable and doesn’t overload the legacy RAN network or mobile core network, since the IP encapsulated calls are offloaded to the VoIP or IMS network. All such approaches would presumably migrate ultimately to IMS. UbiquiSys and Airvana are involved in SIP/IMS based femtocells, as is Tatara Systems (News - Alert), which has developed a core infrastructure FMC application server that supports SIP-based femtocells. The Tatara Convergence Server effectively provides the SIP-MSC Interworking Function (IWF) to enable integration of SIP based femtocells into the core network. The open Tatara Convergence Server is said to work with all SIP-based femtocells.

Tatara Systems recently teamed up with AirWalk Communications (News - Alert), formerly known for their IP-RAN solutions, to deliver SIP-based femtocell and macrocell network solutions. The solution enables CDMA network operators to leverage VoIP or IMS infrastructure with AirWalk’s EdgePoint femtocell and OneRAN macrocell solutions. The key component of this system is an IOS-SIP adapter sitting in the EdgePoint or OneRAN products that communicates directly with the Tatara CDMA 1xRTT Convergence Server (TCS/CDMA-1xRTT), which performs the SIP/IMS interworking and ensures service parity with the macro network.

The only other CDMA femtocells currently available can be found in Sprint (News - Alert)’s “Airave” CDMA femtocell service launched in Denver and Indianapolis. (The Airave femtocell is actually a rebranded version of Samsung’s Ubicell.)

And Now, in the Privacy of Your Own Home...

Aricent (News - Alert) offers more than 125 software products, ranging from complex applications to network core technology for leading equipment/device manufacturers and service providers. It offers everything from switching, security, quality of service and network protocols to middleware, multimedia codecs, service provisioning and billing mediation software.

Aricent’s Ajay Gupta, Vice President of the Wireless and Convergence Business Unit, says, “The femtocell market has been evolving at a reasonable pace. Technology trials are underway, interoperability testing with the existing core network is occurring. Big carriers are becoming involved in Europe, such as Vodafone (News - Alert), O2, Telfonica, and Telecom Italia – all of them have announced femtocell trials, and providers are trying to figure out how femtocells are going to be managed. More importantly, they’re determining how these femtocells will be marketed. There needs to be market channels, and those channels are now being established. Companies such as NETGEAR know how to sell devices into the home, unlike telecom companies. Cisco (News - Alert) has bought a stake in the U.K.-based start-up company, IP.access, which makes femtocell devices. So clearly they have shown their intentions. Many such activities are underway, which means that the mass-market channels are becoming established.”

“Vendors will integrate the technology of femtocell players as an adjunct to or actually integrated into their own mass-market products, such as home gateways and DSL routers, says Gupta. “You can see a parallel with the way DSL and WiFi devices have been paired. Early on we had DSL routers, and then WiFi routers, and then the two were integrated into one device. We’ll also see the advent of a device that is 3G on side and DSL on the other. There could also be devices incorporating WiFi or WiMAX (News - Alert), with IMS (IP Multimedia Subsystem) compatibility. But clearly the way technology is shaping up, 3G is the most mature technology that people are trialing in terms of femtocells, because 3G, from a mobility perspective, have very clear, defined standards, and has very clear implementations, and no drastic changes in the network are needed. Some IMS-based companies are converting 3G calls into IMS-based call and carrying the call over an IMS network. But our view is that 3G will be used at the backend, or perhaps UMA (Unlicensed Mobile Access) at the backend.”

“Aricent has several roles in this space,” says Gupta. “First, we help customers develop femtocells. Secondly, we help in the development of femto-gateways. A gateway device sits at the network core and aggregates all of the traffic that comes from various femtocells. It’s a very high-capacity device. Thirdly, we recently launched a unique practice called the ‘Femto Deployment Practice’. The objective of this practice is to help either the equipment vendors who are system integrating the whole network – who are predominantly large players – or the network operators. We help them deploy these femtocells in the network, which involves helping them with lab trials and all issues related to interoperability, and we help them do system integration. We have tests of our own, a deployment test suite around which we can test the femto-network and, after doing the lab trials, take it to the level of friendly user trials, and then we help it get ready for actual deployment.”

“So we help customers determine how they’re going to do system integration,” says Gupta, “and how they will handle all of the Tier 1 and Tier 2 calls they’ll receive from a multitude of femtocell devices sitting in people’s homes. We can also head up the establishment of a technical help desk. We don’t handle consumer calls ourselves but we can help our provider customers with ways of handling customer calls to sort out any operating problems.”

To Protect and Serve

NextPoint (News - Alert) Networks’s forte is interconnect, access, session border control and FMC solutions for network operators that ease the management of world’s increasingly complex networks. In particular, their NextPoint IntelliConnect System consists of six products and three hardware platforms that deliver intelligent, secure and scalable session management between fixed, mobile and blended IP networks. NextPoint products can be used as standalone devices or in combination with other members of the IntelliConnect System.

Mark Pugerude (News - Alert), CMO of NextPoint says, “We have a system that’s purpose-built for femto gateways, and security gateway functionality. It’s part of the NextPoint Networks suite of mobility and wireless systems. We have worldwide distribution agreements with major manufacturers as well as some live field trials. So we think we’re probably the market leader in this space. In FMC, NextPoint is actually agnostic on which technology will win or needs to win. Whether it’s femtocells on one side or dual-mode handsets and WiFi on the other, we provide a system that addresses most of the FMC market. We have a solution for both opportunities, so we’re not biased in any way.”

“Security gateways are involved in aggregating many devices where you authenticate and encrypt users onto a platform that has large scale,” says Pugerude, “and then you groom that traffic back into the core network. That network traffic – be it voice, data, multimedia, IM, presence, or what-not – requires some session management, which is why NextPoint resulted from the merger of NexTone (News - Alert)’s expertise in session border control and management and Reef Point’s expertise in security gateways. It makes for a very powerful FMC platform. Reef Point had success in its own right in the femto gateway area, but we saw that the future was coming up on us pretty rapidly with our real-world experience involving femto deployments. Femto aggregation is one thing, but then really managing both the user experience and network elements and the flow of the traffic will require session management. By combining both companies we leverage both their talent and core technologies to address a much wider market of both fixed and mobile users. The mobile world continues to grow at a very high pace, while fixed continues to convert from TDM to IP. Thus, we see the convergence of IP endpoints – ultimately all handsets will be SIP IP endpoints – which require session border control functionality as well as large-scale security gateway functionality.”

“We have worldwide distribution agreements with Alcatel Lucent,” says Pugerude, “and with Samsung and ZTE (News - Alert), one of the largest manufacturers in China, and we have deals with a couple of others which I’m not able to reveal at this time.”

“Femtocells are hot in that they scratch a consumer itch,” says Pugerude. “Consumers want better coverage in their home or at work, and they want an unlimited call plan while they’re at home. Operators admire femtocells because they reduce backhaul and they employ the same fulfillment logistics channel used today to sell handsets. So there’s an easy alignment of interests.”

Natasha Tamaskar (News - Alert), VP of Product Marketing and Management at NextPoint, says, “Operators are adopting femtocell technology because today there aren’t that many WiFi-enabled handsets available in the market. It’s not just about supporting WiFi on a handset, it’s about supporting security functions on the handset as well, because now the handset really needs to connect over an insecure network back into the mobile core. These functions are a bit difficult to support on a small handset, yet people want more and more advanced features and slick-looking handsets. When dual-mode handsets first appeared, they tended to be very bulky and consumed a lot of power, which made them somewhat unattractive. But we’re starting to see more handsets going that route. Having said that, it’s still a lot easier for a person to retain their most interesting handset of their choice and then connect back to the mobile core using the femtocell technology, which is really a plug-and-play device that plugs into your WiFi router and connects back into the mobile core.”

“Operators are also trying to provide very attractive plans for such devices in that if customers connect from their home, then those minutes are sometimes given for free,” says Tamaskar. “These models make it attractive not just for the operator but for the consumer as well to use this technology. Initially we are seeing that most trials seem to be moving toward that model. Some Tier 1 operators are trying to do everything, but they’ve initially decided to start with femtocells instead of dual-mode handsets. Eventually, as the traffic becomes SIP-aware, there will be a need to support dual-mode handsets. In any case NextPoint can provide the security gateway to which either type of device needs to connect. We are happy for both femtocell and dual-mode handset technologies to succeed.”

There’s a potential for millions of femtocells to appear in the U.S. in a very short time. Mass production and widespread use of femtocells will improve coverage, diversify services, and make the public even more mobile than they were previously. IT

Richard Grigonis (News - Alert) is Executive Editor of TMC’s IP Communications Group.


The following companies were mentioned in this article:

Airvana (

AirWalk Communications (

Aricent (

Femto Forum (

ip.access (

Kineto Wireless (

NextPoint Networks (

Sprint Nextel (

Ubiquisys (

Tatara Systems (


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