Jonathan Morgan is Senior Manager of service provider product marketing for Cisco Systems. Mr Morgan was previously Vice President of Product Marketing for Tatara Systems, Director of Product Management for Appian Communications and has also held numerous management positions at Fujitsu Network Communications. Jonathan Morgan holds a BSEE from Washington University in St. Louis and an MSEE from Rutgers University.
In order to address coverage and capacity requirements in the home, enterprise and hotspot markets, mobile operators need to expand service offerings over multiple new access networks. Femtocell technologies are a promising solution but are currently suffering from a lack of standardized deployments in the industry. Only truly standard multi-vendor plug-n-play femtocell solutions can lower the total cost of ownership, enable new services and provide a seamless evolution to LTE and IMS.
Mobile operators realize the importance of expanding service offerings to address the home, enterprise and hotspot markets. This requires operators to expand service offerings over multiple new access networks, including providing access over unsecured, un-trusted networks - primarily existing fixed networks such as broadband DSL, fiber to the home, or cable broadband networks - using technologies such as femtocells. Currently, femtocell rollouts tend to focus around issues associated with the femtocell access point such as price points, power and security requirements. Operators have also been pressed for time to get initial femtocell network trials and deployments completed quickly. This has led to a lack of network focus in the vendor community and a lack of standardized deployments in the industry. With this consideration, there are many questions around the network to think about: • Do UMTS femtocell network solutions work with any femtocell access point (are they standard)? • How can operators minimize the number of platforms needed to support multi-access technologies and new demands for different femtocell service deployments? • How does a standardized femtocell solution not only meet network needs, but provide an attractive business case to the subscriber? and; • How does the UMTS femtocell solution evolve to LTE or integrate with IMS? Is it standard? The Iuh interface between the femtocell, known as the Home Node B (HNB), and the Home Node B Gateway (HNB-GW) has been standardized in 3GPP Release 8. The HNB-GW interworks circuit switch signaling and bearer to standard Mobile Switching Centers (MSCs) using the IuCS interface, interworks packet switch signaling and bearer to standard Serving GPRS Support Nodes (SGSNs) using the IuPS interface, and provides a Security Gateway function. An open interface implementation between a core network and the access network is critical to enabling a low cost, multi-vendor femtocell environment. Standardization allows operators to deploy femtocell and network equipment in a multi-vendor environment, thereby opening up competition, accelerating commercial deployments and lowering costs. The first demonstration of a standard femtocell to HNB-GW occurred in June 2009 at the Femtocells World Summit in London. It was an example of how a true standard multi-vendor plug-n-play femtocell rollout can lower the total cost of ownership with limited impact to the mobile device and the core network. Home Node B consumer Femtocells (called the Home Node-B in 3GPP standards) are low-power access points that operate in licensed spectrum and provide dedicated mobile coverage, capacity, and potentially new services in the home. Consumer femtocells utilize Internet broadband (xDSL, cable, FTTH) connecting to the mobile operator’s core via generic IP access networks. To provide secure transactions between the HNB and the core network the HNB establishes an IPSec tunnel to a Security Gateway (SeGW) is discovered and authenticated; by the management system and establishes; the circuit switch (CS) and packet switch (PS) sessions to the HNB-GW using the standard Iuh interface. A consumer femtocell typically supports 4-6 mobile sessions simultaneously and may provide local IP access for mobile data sessions. Home Node B enterprise The femtocell benefits of dedicated radio, lower cost deployment, zero touch and small form factor have expanded beyond consumer applications into the enterprise. Enterprise applications of femtocells are rapidly developing in the market place. Femtocells eliminate previous cost-prohibitive barriers to deploying dedicated radio capacity to a large segment of small and medium businesses as well as large enterprises. However, unique deployment requirements will have to be met to enable this emerging segment of the femtocell market. An enterprise femtocell typically supports 16 or more mobile sessions and may provide local IP access, IP LAN services and IPX integration. Enterprise femtocell deployments may require multi-service capabilities such as Session Initiation Protocol (SIP) routing, IP Multimedia Subsystem (IMS) interworking, and advanced IP routing and security. Security gateway A security gateway provides a high performance, intelligent, secure communications gateway which enables subscribers’ seamless access as they roam between external trusted networks and un-trusted networks, such as femtocells. The security gateway terminates and manages IPSec IKEv2 tunnels from the femtocell, provides authentication for the femtocell, and directs traffic to the HNB management system and HNB-GW. Home Node-B gateway (HNB-GW) The HNB-GW terminates the 3GPP standard Iuh protocol, aggregates large number of femtocell Iuh interfaces, and routes user sessions to the core network. The HNB-GW interworks circuit switch signaling and bearer to standard MSCs using the IuCS interface, and interworks packet switch signaling and bearer to standard SGSNs using the IuPS interface. Both IP and ATM transport for circuit switch and packet switch sessions can be supported simultaneously on the platform. Home Node B management The HNB management system utilizes a standard TR-069 architecture. The management system performs functions such as location verification, auto-configuration of the femtocell, core network element assignment (HNB-GW, SeGW), and remote management and control. Simplicity is key Many of the pre-standard femtocell solutions required multiple platforms (often from different vendors) to terminate and aggregate femtocells. This can be costly, with multiple hops and is complicated to manage. By integrating the femtocell aggregation functions, the security gateway function and potentially other packet core elements (why not the SGSN or GGSN?) into a single flexible, scalable, and highly available platform, the capital and operating expenses of the network will be lowered drastically. Monetization With the mobile broadband tidal wave, bandwidth is rising faster than revenue. Operators are looking for as many options as possible to create new revenue streams and lower both the CapEx and OpEx. The same intelligence and policy control capabilities being deployed with macro networks must be deployed for standardized femtocell networks to provide resource management, service personalization, and new revenue creation. With a femtocell being under licensed spectrum, the operator has the opportunity to ‘own’ the home market and offer new services, including: • specialized call tariffs and call features, e.g., multi-ring across mobile and home devices; • unlimited data services, and/or tiered data services; and • new home based intelligent services, such as: - control of intelligent home environment; - receive MMS from security camera when door bell rings; - notification through SMS when children arrive home; and - presence and location services. Evolution to LTE and IMS While in 2G and 3G technologies femtocells are a more recent addition to the standards, LTE standardization took into account femtocell architectures from day one. Many operators are considering small cells as part of their initial LTE rollouts to maximize coverage. The 3G network solutions, such as the HNB-GW, must be upgradeable to support seamless evolution from 3G to 4G, including simultaneous support for both 3G and 4G. The same holds true for IMS - the long-term architecture for 3GPP. The network solution must support a seamless path to IMS. Conclusions Mobile operators are looking to expand service offerings to address the home, enterprise, and hotspot markets including femtocells. The industry must commit to open standards to allow operators to meet business and market objectives as well as needing to enable the widespread adoption of femtocells. When planning rollouts, a true standard multi-vendor plug-n-play femtocell solution can lower the total cost of ownership, enable new services and provide a seamless evolution to LTE and IMS.