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  • Wireless Home Gateway Handover, roaming, keletkező veszteségek
  • Tóth Balázs Viktor Wireless Home Gateway 1. 3G Home Gateway Project: Several European mobile operators are investigating the possibility of integrating a UMTS base station module into a home gateway connected via ADSL. The idea is to provide an extension of the 3G network, with a home gateway transformed into a simplified 3G pico base station, and DSL access providing the backhaul between the home and the operator's core network. This network extension would provide dedicated 3G access (via WCDMA or HSDPA) for any type of cellular service: voice, Internet browsing, content download, TV streaming, etc. If this idea turns out to be feasible, there could be many implications for the telecoms consumer market. The service could potentially offer a dedicated connection to the 3G network when at home, for any 3G device, with a guaranteed data rate. That should enable 3G service users to enjoy a much better quality of service at home than when they are using the shared 3G infrastructure - no network congestion, no interference from other users and no interference from other radio technologies. HSDPA could theoretically deliver several Mbit/s in this configuration. A key benefit is that there is no impact on the device, as the same access technology is used at home as well as outside (contrary to dual-mode approaches). It can also re-use existing 3G handover technology to switch between the home cell and the rest of the 3G network. The last - but not least - advantage is that it gives mobile operators the opportunity to design residential cellular-based services for the consumer market. In particular, it would enable them to offer specific home tariffs for voice and data services. That could be a decisive factor when competing against fixed ISPs and alternative wireless access technologies, such as WiFi or WiMAX. It also opens up some interesting opportunities to the operators for extending their cellular networks. This solution could mean that the customers finance - at least partially - an increase in network capacity. There are two big challenges: • the 3G home gateway costs need to be very low (typically a few hundreds euros), which requires the simplification of the UMTS Node B equipment that would be integrated into the ADSL home gateway. • the 3G radio network configuration is tricky. The equipment needs to be self-installable by the user at home, and at the same time, the operator must avoid interference with the rest of its 3G network. These are big hurdles, but assuming they can be solved in the next two to three years, the implications for telecom operators and service providers could be huge. Today, a high proportion of mobile voice calls are made at home - figures of 30-40% are often quoted. At the same time, mobile users are generating more and more mobile data traffic while at home. It is clearly a challenge for mobile operators to keep benefiting from this situation, and at the same time offering more attractive services and good connectivity to users at home. This project could be an interesting solution, but only for those mobile operators that have control over broadband fixed 2
  • Tóth Balázs Viktor Wireless Home Gateway lines. Fixed-mobile convergence so far has mostly meant cannibalising mobile traffic by re- routing traffic through fixed lines. 3 View slide
  • Tóth Balázs Viktor Wireless Home Gateway 2. Getting In Formation for the 'Handoff': Handing off telephone calls from a cellular-telephone network to a cable system is a challenge that has yet to be surmounted by any communications-service provider. But dual-mode wireless phones, wireless fidelity (Wi-Fi) gateways and a combination of hardware and software that use communications standards known as the Internet Multimedia Subsystem (IMS) are expected to be the key ingredients. The ability to switch phone calls from the wireless network to the cable network inside a consumer's home is one of the key goals. 30% of all cell phone minutes occur inside the home, so such handoffs would reduce the amount of voice traffic on cell phone networks. In order to switch a cellular phone call from the wireless network to a cable system, a consumer would need a new handset and the cable operator would have to install new equipment in the home and in their network. To start, a consumer would have to buy a new “dual-mode” cell phone, which would be capable of communicating with the wireless network and cable's Internet protocol infrastructure. Two Radios A dual-mode handset has two radios. One radio relays voice calls to and from the cellular network. The other radio is equipped to communicate with a wireless-networking device, known as a Wi-Fi gateway, that the cable operator would install in the home. The new dual-mode phone would also contain IMS software, which would translate the contents of a call from the wireless network to the cable network. The IMS client communicates to a wireless access point in the home using SIP [Session Initiation Protocol] software. The wireless access point would be a new device in the home that would include a Wi-Fi antenna and gateway, a cable modem and a multimedia terminal adapter. That gateway device would communicate through a subscriber's cable modem with an IMS switch, located beside the cable-modem termination system in a cable system headend. That switch would handle communication with the cellular phone network to transfer phone calls. As the dual-mode handset moves into the home, it automatically checks to see for an authorized access point as signal power declines on the call. The cell phone is preprogrammed to “look” for the Wi-Fi gateway. The gateway, in turn, has been programmed to receive signals from that particular cell phone. If, for instance, the strength of a signal starts to weaken while a caller is still using the dual-mode handset inside the home, the handset will automatically switch the call to the Wi-Fi gateway and onto the cable network, before it is lost. 4 View slide
  • Tóth Balázs Viktor Wireless Home Gateway The new dual-mode phones allow consumers to configure some options. They may, for instance, want to automatically switch phone calls to the cable network as soon as they are inside the home, without waiting for a signal to degrade. The consumers can configure it so it automatically hits the Wi-Fi access point, saving cell phone minutes, or can stay on the cellular network to the point it starts to degrade. The HeadEnd Setup Once the call is handed off to the in-home wireless gateway, the voice packets are sent through the cable plant to the Internet Multimedia Subsystem switch in the headend. The Internet Multimedia Subsystem switch will then communicate to the cellular switches in network. Calls that travel through the IMS switch then proceed through a media gateway, which converts the call from the packets that adhere to the Internet communications protocol used by cable to the code-division multiple access (CDMA). Cable operators who've deployed voice-over-Internet protocol service have already installed media gateways. Motorola is building wireless gateways for use in cable networks that would cost $100 apiece. Those gateways have advanced capabilities, including a Wi-Fi router with a firewall and software to insure different applications running through the gateway receive the bandwidth they need. Voice may be one session, and customers may have multiple PCs running, including someone downloading video off the same gateway. They want to give priority to voice traffic. Another aspect is security. They want to make sure the call is encrypted and authorized. They want only authorized users sending information back up to network. Marrying the Two When a consumer brings home a dual-mode handset and gets the Wi-Fi gateway installed, prompts on the cell phone will give the subscriber a series of commands to “pair” the cell phone with the gateway. It has automatic pairing capability, much like how a newly installed cable modem “looks” for the cable-modem termination system in the cable headend to launch high- speed Internet access. The quality of signal coverage inside the home will degrade the further a cell phone user is from a wireless access point, just like a personal computer in a wireless network in a home. Typically, the cell phone connection in the home is not great in many parts of the home. Wi-Fi tends to have a much better signal strength. It will be much better than cellular experience. The new cell phones also will conserve battery strength. The wireless access point is always throwing out beacons looking for traffic. We may have a power save function so the gateway isn't pinging the cell phone constantly [and draining the battery, such as when the overnight hours when the cell phone is in the house, but the user is asleep. 5
  • Tóth Balázs Viktor Wireless Home Gateway Motorola's gateway supports both 802.11b and 802.11g formats. The two wireless- communications specifications are capable of delivering data at speeds of 11 Megabits per second and 50 Mbps, respectively. Motorola intends to start marketing dual mode handsets “shortly,” even though cell phone-to-cable hand-off services have not been deployed. People buy cell phones almost every year, adding that in many cases, handsets come free, depending on the level of services or features a consumer buys. And the promise of saving minutes might just be enough to entice consumers to get yet another cell phone. The Step-by-Step Handoff How cellular traffic will be passed to cable: 1. A consumer receives a phone call on their cell phone while at home. An in-home gateway device, that includes both a wireless antenna and a cable modem, pings 2. the cell phone, offering to take over transmission of the call. The modem in the device sends a signal back through the cable plant to an Internet Multimedia 3. Subsystem switch in the headend. 4. The switch transfers the call from the wireless network to the cable network. 6
  • Tóth Balázs Viktor Wireless Home Gateway 3. Motorola Residential Seamless Mobility Gateway (RSG) enables VoIP- to-mobile roaming: Motorola, claims that it "broke down the barrier between traditional home and wireless phone service." They are speaking of their new innovative Motorola Residential Seamless Mobility Gateway (RSG) lets consumers use the same mobile device -- and the same number -- as they roam in and out of their homes. The real takeway from this announcement is that this product takes WiFi-to-cellular handover control out of the hands of the carrier and into the hands of the consumer. The announcement could breathe new life to dual-mode handsets market, which has been greatly hampered by the control that cellular network operators have exerted over the handover exchange process. Creating an Innovative Home Communications Experience The Motorola RSG family of products packs powerful communication features for our home. The product includes an 802.11b/g wireless access point, a four-port router, and a built-in Voice-over- IP adapter. This technology allows the RSG to run your home network, power standard telephones, and act as a hotspot for your mobile phone. Further, the Motorola RSG can seamlessly transfer voice calls between the home wireless network (WLAN) and the cellular network without interrupting the call, when paired with a dual- mode handset (DMH) and connected to a network and service that supports this feature. Dual- mode handsets are mobile devices that can access both cellular and in-home wireless networks. Motorola RSG products give consumers freedom for personal communications: The products eliminate the hassle of finding a good reception zone in the home, and of managing separate bills, individual calling plans, or "bonus" minutes. Consumers can simply dial a number, and the intelligence in the gateway will automatically route the call to the best available network or service option. Additional features of the Motorola RSG Series include: -- Single-Number Access - Calls made from a dual-mode mobile handset in the home enable consumers to reduce cellular bills. -- Home Network Connectivity - Access your high-speed data connection from anywhere in the home with an 802.11 b/g wireless access point and a four-port wired router. For mobile voice calls, use your home wireless network to compensate for cellular service "dead-spots" within the home. -- Voice Prioritization - Ensure high-quality voice calls while accessing the Internet. -- Portability - Easily plugs into any broadband connection. -- Rich Digital Phone Features - Caller ID, call waiting, three-way 7
  • Tóth Balázs Viktor Wireless Home Gateway calling, and call forwarding. -- Multiple lines - Allows for a shared "family" number as well as individual mobile and landline numbers. -- Power Management - Optimizes the battery life of users' handset through 802.11e U-APSD, radio resource management, and 802.11k measurement pilot. -- Advanced Security - Protect your voice calls and your data with 802.11i security and pre-authentication, IPSEC/PPTP/L2TP NAT tunneling (for VPN pass-through), storage for X.509 device certificate and operator public key as well as mobile pairing. There are two products in the Motorola RSG family: the RSG2500, expected availability Winter 2006, and the RSG3500, expected availability Summer 2006, which adds the ability to power two lines of primary VoIP telephone service within the home. Consumers today want the flexibility of a single number and handset that can be used both in and out of the home, and a solution that can bridge landline, cellular and digital phone services. This latest Motorola innovation breaks traditional concepts of personal communication without sacrificing ease of use or functionality. he Motorola RSG creates one integrated system for communicating in and out of the home, helping consumers realize the economical advantage of simplified billing and improved service. Introducing an All-In-One Cable Modem Gateway Motorola today also introduced the SVG2500 Wireless VoIP Cable Modem Gateway, an all-in- one home communications hub that integrates digital phone service and a wireless access point with a reliable Motorola cable modem. Soon, the SVG family will support the fixed-mobile convergence features of the RSG service mentioned above, offering service providers an integrated product for delivering 'quadruple play' offering of voice, video, data, and wireless services to customers. The Motorola SVG2500 enables the simultaneous use of digital phone and high-speed data services, and also supports a variety of popular phone services including caller ID, call waiting, call forwarding, and more. The product's advanced routing features allow for multiple PCs to be connected without the need for a stand-alone hub or router - reducing both cost and clutter. The SVG2500 is easy to set-up and use, featuring plug-and-play installation and an intuitive Web-based diagnostic function for quick troubleshooting. The product is expected to be available in Spring 2006. 8
  • Tóth Balázs Viktor Wireless Home Gateway 4. BridgePort Networks Showcases Seamless IMS Voice Call Handover Between GSM and WI-FI Networks AT 3GSM World Congress IN Barcelona: First Interoperable Implementation of 3GPP’s IMS Voice Call Continuity Technical Requirements BridgePort Networks, the leader in MobileVoIP convergence, announced that it will be showcasing the first instance of seamless IMS voice call handover between GSM and Wi-Fi Networks. BridgePort Networks has successfully completed interoperability of its NomadicONE IMS Convergence Server (ICS) with a commercial IMS Call Session Control Function (CSCF) platform and multiple Mobile Switching Centers (MSCs) and other associated network infrastructure components. IMS is a platform that can be used by operators to flexibly develop and deploy a range of multimedia services for 2.5G and 3G mobile networks. BridgePort Networks’ NomadicONE ICS IMS-based fixed-mobile convergence solution provides mobile providers, fixed providers, cable providers and MVNOs the ability to offer single phone number voice services that can seamlessly hand over in-process voice calls between circuit- switched cellular and Voice-over-IP over Wi-Fi access networks. The solution conforms to technical requirements recently ratified by the standards bodies 3GPP and 3GPP2 for IMS to circuit switched seamless voice handover, known as Voice Call Continuity (VCC). The NomadicONE ICS is a specialized application server in the IMS architecture that supports GSM, CDMA and UMTS networks, and implements the IMS Controlled Model (ICM) method of handover per 3GPP technical requirements and, for CDMA2000 networks, the Call Transfer Model (CTM) method of handover per 3GPP2 technical requirements. In addition, NomadicONE ICS adds a number of optional advanced capabilities including Home Location Register (HLR) access for single registration and enhanced supplementary services support and mobile messaging support over Wi-Fi. “Fixed-mobile convergence is the key business case for IMS deployment”, said Mike Mulica, President and CEO of BridgePort Networks. “Seamless voice call handover conforming to IMS 3GPP technical requirements between mobile and Wi-Fi networks is ready for market trials today. It can be commercially deployed this year and is supported by both handsets for both mass consumer and enterprise markets. The revenue driven by these converged voice services will outweigh those of all other IMS applications.” A growing number of dual-mode cellular/Wi-Fi handsets are compatible with the single phone number and seamless cellular to Wi-Fi handover capabilities of the IMS solution incorporating NomadicONE ICS. These include: 9
  • Tóth Balázs Viktor Wireless Home Gateway • GSM/Wi-Fi - Microsoft Windows Mobile devices from HP targeting the enterprise and small form factor, low cost Linux smartphones from E28, suitable for mass consumer use. • CDMA/Wi-Fi - Microsoft Windows Mobile devices, with feature phones in active development. For these devices a number of client software companies have implemented support for single number dual-mode telephony, SIP-based VoIP, security and seamless handover, including BridgePort Networks’ partners: E28 and PCTEL. Megjegyzés: egy konkrét megvalósítás. 10
  • Tóth Balázs Viktor Wireless Home Gateway 5. Architectures for Fixed-Mobile Convergence: IMS vs. UMA: Unlicensed Mobile Access (UMA) and the IP Multimedia Subsystem (IMS) -- two standard architectures under the 3GPP umbrella -- both support fixed-mobile convergence (FMC). But their approaches to FMC have little in common. UMA is a highly constrained approach to a single service -- dual-mode access to GSM networks -- while IMS is an open platform for all types of services and all types of networks. UMA offers mobile network operators (MNOs) a quick fix, but IMS promises profitable new services and sustainable growth for all service providers. Dual-mode Access - FMC in Action FMC encompasses a number of innovative applications and services, but dual-mode phones and converged cellular/Wi-Fi access currently receive the most attention. Dual-mode phones are special wireless handsets that contain both Wi-Fi and cellular radios. The cellular radio accesses conventional cellular service, while the Wi-Fi radio accesses wireless LANs in homes, offices or public hot spots. During a phone call, the handset monitors the presence of Wi-Fi and cellular service and selects the "better" access mode based on signal strength and other criteria. As the user moves between cellular and Wi-Fi coverage areas, the handset automatically switches between access modes. A make-before-break handoff procedure ensures seamless transitions. Dual-mode access extends mobile communication into office buildings and other sites that cellular service may not reach. And it can save money by using public IP networks to avoid certain airtime and roaming charges. UMA and IMS both support dual-mode access, and to end users there is no obvious difference -- at least at first glance. But the architectural models are poles apart, and that makes all the difference in terms of network fit, scalability, support for additional services, and market applicability. UMA -- Gateway-based Access Convergence With an ordinary GSM cell phone -- or the cellular side of a GSM dual-mode phone -- voice traffic travels over radio waves to a cell tower. From the tower, the traffic is backhauled to a base station controller (BSC) that relays the traffic to the core. As the handset moves from place to place, the radio link moves from tower to tower and the backhaul link moves from BSC to BSC. GSM standards dictate the handoff procedure. To support dual-mode access, UMA relies on a special gateway -- called a UMA Network Controller (UNC) -- at the edge of the mobile core network (Figure 1). When the handset is in Wi-Fi mode, an IP tunnel or virtual private network (VPN) carries GSM traffic across the public IP network to a UNC. The UNC removes the IP envelope and forwards the GSM traffic to the carrier core. To the core network, the UNC looks like a standard BSC. So when a handset transitions between cellular and Wi-Fi access, the core network perceives it as a BSC-to-BSC handoff. 11
  • Tóth Balázs Viktor Wireless Home Gateway UMA's intimate relationship with cellular technology is both its strength and its weakness. On the upside, UNC gateways can be deployed with only simple, familiar changes to the carrier infrastructure. Adding a UNC is like expanding the network by adding a BSC. And since voice and signaling traffic remains in GSM format, even as it tunnels through the Internet, the MNO does not have to master new voice or signaling protocols or deal with the challenges of VoIP. On the downside, UMA works only with GSM cellular networks and can be deployed only by facilities-based MNOs. It holds no benefit for traditional wireline operators, VoIP providers, or even mobile virtual network operators (MVNOs). UMA cannot leverage the flexibility and revenue potential of IP telephony, since voice traffic remains in GSM format. Designed specifically for dual-mode cellular/Wi-Fi access, UMA does not support other FMC services and cannot extend FMC services to wired handsets, softphones or other types of devices. Moreover, to expand UMA service capacity, the carrier must deploy more and more gateway boxes, adding both cost and complexity to network operations. Consequently, most service providers view UMA as narrow and shortsighted -- an inadequate long-term response to the FMC opportunity. IMS -- Server-based Service Convergence Unlike UMA, which delivers only a limited form of access convergence, IMS implements true service convergence, enabling consistent service delivery across all types of access networks and user devices. To achieve network independence, the IMS framework assigns service and control functions to three different layers (Figure 2). The transport layer is responsible for security, interoperation between different types of networks, and basic access and transport. The control layer handles routing, policy enforcement, subscriber databases, etc. The service layer is home to familiar applications like hosted IP PBX as well as new services like Voice Call Continuity (VCC) -- the ability to move active voice sessions between IP and circuit-switched domains. Communication between the layers relies on standard protocols like SIP and Diameter. This 12
  • Tóth Balázs Viktor Wireless Home Gateway standards-based layering gives IMS its flexibility, promoting rapid rollout of new applications and allowing services to operate across diverse network technologies. With IMS, dual-mode access and other FMC services are controlled from the application layer. A VCC server creates end-to-end connections by signaling networks in their native protocols and directing call legs to meet at an "anchor point." VCC also allows active sessions to move without disruption between different networks and devices. VCC is architected as two IMS functions: Network Domain Selection (NeDS) maintains information on the real-time whereabouts of each terminal device and call leg. The Call Continuity Control Function (CCCF) uses standard SIP and SS7 signaling protocols to control the movement of active calls between networks and between terminal devices. With a media gateway (MGW) as the anchor point, VCC supports the same sort of dual-mode access as UMA -- plus a lot more. Consider, for example, a phone call between a dual-mode phone and a traditional wireline phone (Figure 3). As the call begins, the dual-mode phone connects via a cellular link. The VCC server signals for two call legs -- a cellular leg from the dual-mode phone and a POTS (Plain Old Telephone Service) leg from the wireline phone. The call legs meet at the anchor point to create an end-to-end connection. As the dual-mode handset moves from cellular to Wi-Fi coverage, the VCC server signals for an IP call leg between the handset and the anchor point. It instructs the MGW to join the new call leg to the active session and then cancels the cellular leg. The 13
  • Tóth Balázs Viktor Wireless Home Gateway conversation continues uninterrupted as the dual-mode handset transitions seamlessly from cellular to Wi-Fi access. Beyond Dual-Mode Access Network independence allows IMS to support a broader range of FMC services than UMA. Besides transferring call legs between two sides of a dual-mode phone, VCC can move an active call between completely separate devices. For example, a user can start a conversation on the desktop phone in her office and then move it uninterrupted to her cellular phone as she walks to her car. VCC can also route call legs over the most favorable paths: least cost, best quality, etc. And because VCC controls calls through signaling -- media traffic never passes through the VCC server -- IMS avoids the scaling challenges of UMA's gateway-based design. Or course, IMS supports more than just FMC. With its layered design, IMS allows users to access consistent services from any type of terminal device -- wired or wireless, TDM-based or IP-based -- and to mix and match different media -- voice, data, video, IM -- freely. By insulating applications from network technology, IMS promotes rapid innovation and lays the foundation for a new generation of converged multimedia services. Indeed, IMS is the telecom industry's widely accepted vision of the future. It has been adopted by international standards organizations for both fixed and mobile communication, including 3GPP, 3GPP2, CableLabs, ETSI and the ITU. Admittedly, IMS is more complex than UMA. In its fullest form, IMS requires a service provider to introduce a new network control system. Still, there is no need to roll out all of IMS at once. Many IMS application platforms work equally well with the VoIP softswitching systems that are 14
  • Tóth Balázs Viktor Wireless Home Gateway already in place. Service providers can begin by adding FMC support to their existing VoIP networks and evolve to IMS if and when it makes good business sense. Conclusion Although UMA and IMS both support FMC, their value to service providers differs dramatically. UMA supports only a single application -- dual-mode access -- and only for GSM network operators. IMS supports an endless array of applications, including dual-mode access, for all types of service providers. UMA addresses a niche opportunity, while IMS creates a flexible, scalable platform for sustained growth and long-term profitability. 15
  • Tóth Balázs Viktor Wireless Home Gateway 6. SEAMLESS ROAMING: ADVANTAGES TO MOBILE OPERATORS AND THEIR SUBSCRIBERS: Seamless roaming enables a mobile operator's data subscribers to remain continuously connected as they cross network boundaries and use different radio access networks, including Wi-Fi, General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), and emerging technologies such as WiMAX. Subscribers retain the same IP address for the duration of the session, so the mobile operator can continually offer for-fee content and services. The operator can also push software updates and troubleshoot user-specific problems to improve customer satisfaction. The result is more revenue opportunities and stronger subscriber relationships. Cisco offers a seamless roaming solution as part of its Cisco® Mobile Exchange framework. THE CISCO SEAMLESS ROAMING SOLUTION OPTIMIZES THE TIME THE MOBILE OPERATOR CAN INTERACT WITH CUSTOMERS, INCREASING REVENUE AND SERVICE OPPORTUNITIES. EXECUTIVE SUMMARY In today's maturing mobile data services market, mobile service operators can no longer rely solely on price to attract and retain subscribers. Rather, they seek new value-added services that will differentiate their offerings and create new revenue streams. Seamless roaming is one such service, offering a competitive differentiator as well as increased revenue opportunities. It enables client devices-such as laptop computers, personal digital assistants (PDAs), or mobile phones with multiple radio interfaces-to roam freely between multiple mobile networks without losing their connection to the home network. Users interact with the service exactly the same way they did before, so the mobile operator can avoid new expenses for training their support or customer care organizations. Seamless roaming has marked advantages over today's more common nomadic roaming, in which users who cross network boundaries are dynamically assigned a new IP address with each crossing, forcing them to terminate and then reinitiate their application connections. With seamless roaming, in contrast, users maintain an active IP connection despite changing connection types and locations. Applications remain connected, and mobile operators can reach their subscribers at the same IP address no matter if they roam on a train from coast to coast. This translates into more opportunities to deliver for-fee content, offer location-based services (LBS) such as local restaurant reviews, and improve customer support by pushing software updates and troubleshooting user problems. Cisco Systems® offers mobile operators a seamless roaming solution based on the Cisco Mobile Wireless Home Agent, part of the Cisco Mobile Exchange framework. Cisco Mobile Exchange is an open platform that can readily interface with all of the control elements in the mobile network, including Multiple Radio Access networks (RANs), back-end billing systems, and content- 16
  • Tóth Balázs Viktor Wireless Home Gateway filtering and compression solutions. Mobile operators can install and deploy Cisco Mobile Exchange without disrupting any services. Providing an intelligent enforcement layer within the operator's network, Cisco Mobile Exchange is complemented by Cisco partnerships. Cisco has already demonstrated the platform's interoperability with major solutions for RANs, authentication, authorization, and accounting (AAA), content billing, content filtering, and compression, relieving mobile operators of the need to dedicate resources to ensure a smooth deployment. More than 40 mobile operators worldwide have deployed Cisco Mobile Exchange. Cisco continually applies their feedback to add valuable new features, maintaining the platform's innovation and cost effectiveness. This white paper explains the service opportunity and provides an overview of how the solution works. SERVICE OPPORTUNITY Cellular phone subscribers have long enjoyed the ability to roam between different mobile operators' networks without losing their connection. Until now, however, wireless data subscribers lost their connection whenever they crossed network boundaries or changed access technologies, say, from Ethernet to wireless LAN or from wireless LAN to wireless WAN. During the course of a day, for example, a user might connect through an 802.11x hotspot at an airport, another wireless LAN at work, a GPRS or CDMA network in transit, a cable or DSL modem at home, as well as GSM, UMTS, or WiMAX. Each new connection type required users to reconnect to their applications. The drawbacks of nomadic roaming affect mobile operators as well as their subscribers. The problem is that once a subscriber logs on to another mobile operator's network and receives another IP address, the customer is as good as invisible to the home network. The mobile operator forfeits the ability to deliver for-fee content such as news or sports updates, and cannot deliver customer support services such as pushing software updates or troubleshooting. With seamless roaming the picture changes. Subscribers can enjoy uninterrupted connectivity as they move between service areas covered by different radio technologies and different mobile operators. They don't need to learn anything new or change their habits to acquire the seamless roaming capability, and the mobile operator incurs no additional operational expense. And with persistent knowledge of the customer's IP address, the mobile operator can: • Increase subscriber convenience by simplifying the connection process and eliminating the need to reconnect • Gain more revenue by delivering for-fee content and services whenever the user is connected, even through another operator's network (note that this requires a suitable billing solution, which is also part of the Cisco Mobile Exchange framework) • Deliver location-based services (LBS) such as local restaurant recommendations or directions • Improve service by giving customers the ability to download new software or troubleshoot even if they are connected through another provider's network • Retain knowledge of the user's IP address for the duration of the connection, enabling billing for content and other services 17
  • Tóth Balázs Viktor Wireless Home Gateway CISCO SEAMLESS ROAMING SOLUTION To offer seamless roaming to customers, mobile operators need an always on IP connection that persists regardless of location, movement, or wireless infrastructure. Part of the Cisco Mobile Exchange framework, the Cisco Mobile Wireless Home Agent is based on the Internet Engineering Task Force (IETF) Mobile IP standard (RFC 3344), which identifies a host device by a single IP address even if the device moves its physical point of attachment from one network to another. Subscribers with mobile devices can roam to another network without restarting applications or terminating and reestablishing a connection. Figure 1 illustrates the components of the Cisco seamless roaming solution. Figure 1 Cisco Seamless Roaming Solution 18
  • Tóth Balázs Viktor Wireless Home Gateway User Experience A subscriber with a laptop might start the day by connecting at a coffee shop hotspot. User remains connected while traveling by train to the office. Her mobile operator remains aware of her IP address although she is connected through various foreign agents, and sends her the for-fee news and stock services to which she has subscribed. At the office, her connection switches to her office LAN. Without disconnecting, she travels to a customer site, remaining continuously connected to the office intranet over a GPRS-based VPN service. As she roams between networks, the Cisco Mobile Wireless Home Agent forwards packets at rates appropriate for each connection so that she receives the best performance available. Subscribers don't need to know what kind of coverage is offered in a given location, nor do they need to be aware of network boundaries. They interact with the service exactly as they did before. The solution masks the technology that enables the seamless roaming experience. Behind the Scenes The Cisco seamless roaming solution includes three components: the Cisco Mobile Wireless Home Agent, foreign agents, and mobile nodes. Home Agent The Cisco Mobile Wireless Home Agent is deployed at the mobile operator's data center on the Cisco Catalyst® Multiprocessor WAN Application Module, which is used in the Cisco Catalyst 6500 Series and the Cisco 7600 Series platforms. All traffic sent to and from a subscriber's terminal is routed through the home agent, regardless of its source or destination. As a result, the subscriber retains a constant connection and remains addressable even while roaming across different access networks. That is, the Cisco Mobile Wireless Home Agent serves as an anchor point for subscribers' PCs or PDAs, no matter how many times the subscriber changes link types and crosses network boundaries. When the subscriber establishes a connection, the home agent assigns a home IP address to the mobile device from its own locally configured address pools. The address can be provided from a DHCP server or AAA server. Foreign Agent Foreign agents reside at the network edge, on the premises of other providers or hotspots. They can be provided by Cisco or other vendors. When the foreign agent detects the presence of a mobile device, it transmits a care-of address (CoA) to the device. The mobile device then registers its CoA with the home agent, by way of the foreign agent. The process repeats whenever the mobile device connects to a different foreign agent. In this way, the IP address remains the same until the user deliberately disconnects. Mobile Node Mobile nodes are the terminals that subscribers use, such as notebook computers, PDAs, or mobile phones, as they move between wireless systems. Once a mobile node is assigned an IP 19
  • Tóth Balázs Viktor Wireless Home Gateway address by the home agent, it retains the same address as it roams among different radio technologies. Back-End Billing The Cisco Service Selection Gateway and Cisco Content Services Gateway provide the back-end foundation for seamless roaming. The Cisco Service Selection Gateway enables dynamic service selection and provides continuous enterprise connectivity even if the subscriber is connected through a foreign agent-while riding on a train or traveling on the other side of the country, for example. The Cisco Content Services Gateway, in turn, helps you capitalize on seamless roaming for increased revenues, by enabling content-based billing and captive portal applications. This solution examines packets to ascertain which URLs or domains the subscriber visited or the file names requested. With this information, a mobile operator can apply the correct pricing based on the content retrieved, or else gather data for market research. With seamless roaming, mobile operators never lose knowledge of their subscribers' IP addresses and can therefore offer for-fee content and services such as captive portal applications for more minutes during the day. MOBILE OPERATOR BENEFITS Increased Revenue Opportunities Mobile operators stand to increase revenues in two ways by deploying the Cisco seamless roaming solution. One is by increasing the ability to attract and retain subscribers. Subscribers will be drawn to mobile operators that offer seamless roaming because of the convenience. The other source of increased revenues is longer time to offer fee-based content and services, a result of knowing the subscribers' IP address even when they're roaming. Regardless of the subscriber's location or connection type, the mobile operator can offer and bill for: • Mobile instant messaging • Unified messaging • e-Paging • Mobile voice over IP • Mobile videoconferencing • Location-based services, such as restaurant recommendations What's more, increased revenues do not require additional operational expense. The technology operates behind the scenes and is invisible to subscribers, so the mobile operator does not need to invest in training its customer support department. Network Aggregation The Cisco seamless roaming solution gives mobile network operators the opportunity to combine public WLAN hotspots and mobile data services such as GPRS or CDMA 1x into a unified 20
  • Tóth Balázs Viktor Wireless Home Gateway offering. The appeal of this type of service is growing as more vendors introduce laptops and PDAs that can access either an 802.11 network, if present, or a network based on a mobile data service. The advantage of network aggregation to mobile network operators is in offloading data customers from the licensed spectrum (GPRS or CDMA) to the unlicensed spectrum where available, so that users receive better performance and the operator frees up licensed bandwidth to serve more voice and data traffic. WHY CISCO? The Cisco seamless roaming solution offers unique capabilities that make seamless roaming an attractive service opportunity-back-end billing, security, and quality of service (QoS)-and Cisco Advanced Services helps reduce deployment risk. Back-End Billing The integrated Cisco Content Services Gateway enables mobile operators to deliver fee-based content to subscribers regardless of their location or connection technology. Without seamless roaming, mobile operators lose the opportunity to bill for fee-based content when the user leaves the service area. Security Security options available with Cisco Mobile Exchange include: • Cisco Virtual Private Network Service Module (VPNSM), which provides a highly secure, persistent, IP Security (IPSec) Mobile IP tunnel during roaming • Cisco Firewall Services Module (FWSM), providing stateful firewall protection • Encryption • Restricted access to authorized users • User tracing • Real-time intrusion auditing QoS The Cisco seamless roaming solution provides QoS capabilities that enable mobile operators to assign priority to mission-critical applications. QoS mechanisms enable the operator to identify the different types of traffic and their requirements, divide traffic into classes, and apply policies so that higher-priority traffic, such as Push-to-Talk, receives priority. The mobile operator can take advantage of QoS to offer differentiated pricing, such as first class, business class, and economy class. 21
  • Tóth Balázs Viktor Wireless Home Gateway QoS also provides the ability to forward packets at rates appropriate for each connection. For example, if a user connects to a wireless WAN and then roams to a faster 3G network, the mobile operator needs to change the packet-forwarding rate at the moment the new connection takes over to avoid packet loss (from too high a forwarding rate) or suboptimal performance (from too low a forwarding rate). Cisco Advanced Services Through Cisco Advanced Services, mobile operators gain access to certified experts' in-depth technical knowledge, specialized tools and methodologies, industry-leading research labs, and a network of certified partners to help ensure the delivery of high-quality mobile wireless services. Cisco consultants and engineers help minimize the risk to valuable business assets by working with the mobile operator to plan, design, implement, operate, and optimize mobile wireless networking solutions. Contact your Cisco representative to find out more about how Cisco Advanced Services experts can help improve staff productivity and reduce the total cost of ownership for your network. CONCLUSION Seamless roaming represents an opportunity for mobile operators to strengthen the subscriber relationship, differentiate themselves to attract new subscribers, preserve bandwidth through network aggregation, and increase revenues. The Cisco Mobile Exchange Framework provides a turnkey solution. 22
  • Tóth Balázs Viktor Wireless Home Gateway 7. Employ UMA for cellular/Wi-Fi convergence: Unlicensed Mobile Access (UMA) is a 3rd Generation Partnership Program (3GPP) global specification that provides a standard for service providers to merge mobile networks and wireless LANs (WLANs) into a single seamless access network with one mobile device, one user interface, and a common set of network services for both voice and data. In fact, the UMA solution can converge cellular networks with any IP-based access networks, including wired and wireless technologies such as IEEE 802.16 WiMAX networks, IEEE 802.20 Mobile Broadband Wireless Access (MBWA), and Ultra Wideband (UWB)-based networks (Fig. 1). With UMA, subscribers can move between mobile networks and WLANs with seamless voice and data session continuity as effortlessly and transparently as they move between cells within the mobile network. Seamless in-call handover between the WLAN (Wi-Fi in most cases) and mobile network ensures that the user's location and mobility don't affect the services delivered to the user. The subscriber experiences total service, location, and mobility transparency. The UMA solution effectively creates a parallel radio access network, the UMA Network (UMAN), which interfaces to the mobile core network using existing mobility-enabled, standards-defined interfaces. The mobile core network remains unchanged. The common mobile core network makes it possible to deliver full service, feature, and operational transparency. The existing service provider Business Support Systems (BSS), service delivery systems, content services, regulatory compliance systems, and Operation Support Systems (OSS) will support the UMA network without change. Service enhancements and technology evolution of the mobile core network apply transparently to both the GSM access network and the UMA network. 23
  • Tóth Balázs Viktor Wireless Home Gateway 1. The various elements of a UMA network are shown. UMA architecture for GSM/GPRS The UMA service concept is an end-to-end solution involving subscriber owned or provided elements and new service provider network elements (Fig. 2). From the network equipment perspective, a UMA network controller (UNC) is needed to support UMA service. As far as the subscriber equipment is concerned, what's needed are UMA-enabled mobile stations (handsets), standard WLAN access points (APs), and standard broadband IP subscription. In addition, the UMA network elements interface to standard deployed network equipment in the GSM/GPRS network to enable seamless UMA-GSM/GPRS network mobility. 24
  • Tóth Balázs Viktor Wireless Home Gateway 2. The UMA architecture is built around the network controller. The UNC is the primary network entity of the UMA solution. The UNC interfaces to the GSM/GPRS core network as if it was a conventional GSM/EDGE (Enhanced Data for GSM Evolution) Radio Access Network (GERAN) basestation subsystem. The UNC also interfaces to public or private IP networks to communicate with UMA-enabled handsets. For the GSM/GPRS core network, the UNC provides the standard GSM A interface for circuit-switched voice services and the GPRS Gb interface for packet data services. Within the UMAN, the interface between the UNC and the handsets is defined as the Up interface. The UNC uses standard IP transport to support the Up interfaces to each handset. The UNC maintains end-to-end communication with each mobile handset and relays GSM/GPRS control-plane and user-plane traffic through the A/Gb interface towards the mobile core network. The UNC is responsible for making the IP-based UMAN access network appear as a conventional GERAN to the core network. Its primary functions are to: • provide secure, private communications over open IP networks between handsets and the service provider core network. • provide discovery, registration, and redirection services to allow the handsets to connect to the appropriate UNC. • relay higher-layer mobile systetem and GSM/GPRS core network control signaling. • set up and tear down UMAN bearer connections for circuit and packet services. • transcode the voice bearer from VoIP transport to voice-over-circuit transport towards the conventional pulse-code modulation-based A interface. • emulate paging, handover, and similar radio-access procedures for UMAN mobile access. • provide standards-compliant A and Gb interfaces with appropriate physical, signaling, and bearer interfaces. The UNC contains a security gateway (SeGW) function that implements a secure IP interface towards each handset, using an IPSec tunnel to provide data integrity and confidentiality and IPSec key exchange (IKEv2) for tunnel setup and mutual authentication. SeGW is authenticated 25
  • Tóth Balázs Viktor Wireless Home Gateway using public key-based certificates, whereas subscribers are authenticated using subscriber identity module (SIM) credentials, via extensible authentication protocol (EAP)-SIM. The SeGW implements a Radius interface to the AAA server for EAP-SIM-based subscriber authentication. UMA-enabled mobile stations UMA-enabled mobile systems are WLAN-enabled cellular handsets running UMA client software (Fig. 3). This software enables the WLAN radio within a handset to appear as a parallel radio resource to the GSM radio. By integrating in this fashion, the higher-level services and applications within the handset remain entirely unchanged. The fact that a service may be delivered over the WLAN radio versus GSM radio is entirely abstracted from the higher-level service and control logic within the handset. 3. The various blocks of a UMA-enabled handset are shown. Standard WLAN access points APs provide Wi-Fi coverage and a link to the broadband IP network for the UMA solution. The APs don't require any UMA-specific technology. The UMA mobile devices can use any generic off-the-shelf APs. The AP may be part of a residential wireless LAN, an enterprise wireless LAN, or a public wireless hotspot. Standard broadband IP access The broadband IP subscription provides the wide area backhaul of UMA traffic to the mobile core network. Any always-on, shared Internet access is sufficient. Enterprise subscribers can use the available enterprise IP network access and residential subscribers can use their residential broadband Internet access. The UMA traffic is simply a new, high-value application for the IP access subscription already in place. UMA and UMTS In recent years, a primary focus within the mobile community has been the implementation and market introduction of Universal Mobile Telecommunications System (UMTS) Radio Access 26
  • Tóth Balázs Viktor Wireless Home Gateway Networks (UTRAN). Many operators have launched a UMTS network as a complement to an existing GSM network. There are also stand-alone UMTS operators. While the market drivers behind UMTS deployment are numerous, two primary drivers include the ability to deliver higher-speed mobile data services and to increase the voice capacity of macro radio networks. As UMA was standardized in 3GPP TSG GERAN, operators want to know how UMA will work in concert with a UMTS network. One key aspect to consider is mobility between UMA/Wi-Fi and UMTS coverage areas. From an overall network perspective, seamless handover between UMA and UMTS networks is supported in the UMA standard today. From the GSM core network's perspective, the UNC is perceived as an additional basestation controller. Thus, when a call currently handled by the UNC is handed over to the UMTS radio network controller (RNC), the process is the same as for calls being handed over from a GSM basestation controller to the RNC. Due to the radio characteristics of the 2-GHz spectrum, UMTS is susceptible to higher signal loss inside buildings, so providing acceptable UMTS coverage for high-performance mobile services within subscriber homes and offices is a significant challenge for operators. Because UMA enables the delivery of high-performance, low-cost mobile services within homes and offices, it provides an effective complement to UMTS network rollouts. As it leverages broadband access, UMA (like UMTS) can support high-performance 3G services. In addition, as it leverages existing in-building Wi-Fi networks, UMA lets operators address coverage and range issues of their UMTS network rollouts. UMA support for UMTS core network interfaces One question asked by operators is whether there's a need for 3G Iu support within the 3GPP UMA standard. As mentioned, Iu interface support isn't required to accommodate handover between UMA and UMTS networks. Moreover, operators with UMTS networks can support 3G services today through UMA using the existing A and Gb interfaces (Fig. 4). 27
  • Tóth Balázs Viktor Wireless Home Gateway 4. UMA support for 3G interfaces continues to evolve. However, as there are several UMTS-only operators, and operators with combined GSM/UMTS networks are looking to migrate more traffic to their 3G-serving GPRS support nodes and mobile switching centers, it's logical for the UMA standard to evolve to incorporate Iu interface support. Such a standardization effort is already in progress and supported by major mobile operators and vendors. The UMA solution provides an unprecedented opportunity for mobile service providers to integrate Wi-Fi access with the mobile network. This integration provides an enhanced mobile experience for the subscriber, encouraging greater mobile voice and data service use and consequently greater revenues. 28
  • Tóth Balázs Viktor Wireless Home Gateway 8. Unlicensed Mobile Access: A License to Print Money? Unlicensed mobile access (UMA) will finally bring together Wi-Fi and cellular networks, making it possible for cellular users to place and receive calls seamlessly over either network without having to select one manually or even having to know which network is available. This sounds attractive for cellular users seeking cheaper calls or better indoor coverage: Wi- Fi coverage within the home is often better than cellular, at least in the United States. Revenues lost by fixed service providers as a result of deployment of UMA services. Source: UMA and beyond: Mobile Operators Benefit from Wi-Fi and Cellular Convergence, Senza Fili Consulting. However, fixed operators and VoIP providers may not share the subscribers’ (or mobile operators’) enthusiasm. UMA will likely cause loss of revenues from toll calls that previously ran over the fixed line and that can now be routed through the UMA network. Moreover, the availability of UMA may induce users to cut the cord — or cancel their VoIP subscriptions — resulting in a decline in the number of subscribers and an even larger loss of revenues. Fixed-to-wireless substitution is already taking place, especially in Asia and Europe. UMA will accelerate this trend as it provides a cost-effective, convenient way for subscribers to move their calls over to wireless networks. The Opportunity Of course UMA does not have to be cheap. Mobile operators may decide to charge for UMA at a price similar to that for regular cellular calls. If they do so, however, UMA’s appeal will be limited to improved home coverage, and this would not be sufficient in most markets to justify a rollout. The key marketing advantage of UMA is that it enables mobile operators to price calls selectively, thus reducing the cost only on calls placed from home, the office and possibly 29
  • Tóth Balázs Viktor Wireless Home Gateway from Wi-Fi hotspots, which would otherwise be routed through the incumbent fixed voice lines. Similar experiments in selective pricing in Germany by mobile operator O2 have been a success, because cellular subscribers often prefer to use their personal mobile phones, with all their contact numbers saved, rather than the family line. In addition, calls over UMA will not use the cellular edge infrastructure. This will unload traffic from the network and reduce costs. To maximize the benefits UMA brings, mobile operators are expected to price UMA services at rates comparable to fixed-line calls and, especially in the U.S., to offer flat-fee plans. Considering the usage pattern of U.S. subscribers, a monthly fee of $10 would prove profitable to mobile operators. Size of Loss What will be the size of losses incurred from UMA and comparable Wi-Fi and cellular convergence solutions? By 2010, fixed operators are predicted to lose $1.1 billion: 1• 63 percent due to lost revenues in fixed fees from users who decide they no longer need a fixed line; 2• 37 percent in toll charges from voice traffic that used to be routed over the fixed voice network and now is carried by the subscribers’ broadband connection. It’s difficult for fixed operators to compete with mobile operators that have exclusive access to the spectrum frequencies necessary to offer service and, with UMA, have a way to enter subscribers’ homes and offer a service that can replace the fixed line. It is easier for mobile operators to enter the realm of the fixed operator than it is for fixed operators to move into offering mobile services. The Fixed Edge Fixed operators have a highly valuable asset, too, for which there is even less competition: the copper wire, coax cable or, increasingly in some markets, fiber to the home. Often, however, fixed operators have been not very successful at promoting their core advantage, especially because they have long seen voice as their main source of revenue. While this is changing rapidly, fixed operators have been slow to react, and UMA will put additional pressure on them to do so. For DSL subscribers, the voice call will be transported over the same network in both cases, but the DSL operator is unlikely to gain additional subscriber revenues from UMA calls any more than it can from Skype calls. 30
  • Tóth Balázs Viktor Wireless Home Gateway However, mobile operators will want their subscribers not only to have access to the fixed line broadband connection, but also to be able to offer QoS to ensure good voice connectivity. QoS may offer an interesting way for fixed and cable operators to develop partnerships with mobile operators and gain back some of the lost revenues. Fixed operators can take advantage of UMA, but the key requirement is partnership with a mobile operator that enables them to offer mobile services directly or to bundle them with existing services. In cases where ownership interest exists, the cooperation is easier to establish, and several carriers are working on the synergy that a UMA service closely tied to a fixed network can generate. Another possibility is for the fixed operator to form an MVNO and sell mobile services under its brand using the mobile operator’s network. One caveat is that MVNOs have proved effective so far at targeting specific segments (e.g., Virgin in the UK) but not as effective at targeting wider markets. Fixed operators, on the other hand, historically have targeted the entire community where they offer service. The case of Fusion, BT’s UMA service in the UK, is interesting, as it shows how a fixed operator can enter an MVNO deal with a mobile operator and, at the same time, leverage the fixed infrastructure it owns to offer data and voice connections. In BT’s case, the adoption of UMA is advantageous, as calls from home that are routed through the WLAN are also under the direct control of the operator. VoIP’s New Competition Lower barriers to entry and decreasing prices make the business of providing VoIP service a tough one to be in. Despite great scope for growth, the increasing competition from incumbent operators, cable MSOs, ISPs, and other fixed service providers is only going to exacerbate market conditions. Mobile operators may be the next players to join the fray. Although not designed to be a substitute for VoIP services, UMA effectively can provide a competing service if mobile operators offer a flat-fee service with unlimited usage. Would mobile operators be interested in offering Vonage-like services? They would probably not think of the service in those terms, especially as VoIP is an effective way to commoditize voice calls — something mobile operators are not inclined to promote. From the subscriber perspective, however, both VoIP and UMA offer an alternative to the fixed line and the cost likely will be comparable: a VoIP monthly subscription in the U.S. generally ranges from $20 to $30, roughly equivalent to the estimated $10 per month for an unlimited UMA subscription, assuming more than one subscription per household. UMA has one main advantage over VoIP: Subscribers can use their mobile handsets and numbers to place and receive calls wherever they have access to a Wi-Fi network, while VoIP users must use their fixed handsets and often need a supplementary phone number assigned by the service 31
  • Tóth Balázs Viktor Wireless Home Gateway provider (in addition to their fixed non-VoIP phone line). VoIP service also typically entails another contract and billing relationship. Some VoIP service providers such as Vonage have launched Wi-Fi phones that can be used from home and from other WLANs where the user has access (e.g., at a hotspot or the office). The Wi- Fi phone will increase the service’s convenience for some users who prefer a separate handset for VoIP calls (especially if they still have a fixed line at home), but it is an effective replacement for the cordless phone. Subscribers will still need their cellular phones for mobility. Unlike fixed operators, VoIP service providers still are fighting to get market share, do not have deep pockets and, perhaps more importantly, do not have any more control than mobile operators over the broadband pipe to the home or office. VoIP currently enjoys advantages such as rich features like different mailboxes, conference calls, online account management, and voicemail that can be forwarded to e-mail accounts. Once subscribers start to expect these features, however, mobile operators may decide to introduce them as well; this choice will be facilitated if UMA transitions, as expected, to a SIP-based architecture. 32
  • Tóth Balázs Viktor Wireless Home Gateway 10. How UMA Enables Broadband IMS: Mobile Operators Enthusiastic About the IMS Opportunity, but... For mobile operators looking to capitalize on new revenue streams, the IP Multimedia Subsystems (IMS) architecture promises rapid and cost-effective delivery of compelling new IP-based mobile services such as streaming video, music downloads, interactive gaming and video conferencing. In the face of these exciting opportunities, however, there are concerns that the limited bandwidth, high-latency, and relative high-cost of cellular radio access networks (RANs) may limit the deployment and acceptance of high-bandwidth IMS services. It’s well known that user acceptance of multimedia applications is tied directly to user experience and service cost, which are in turn related to the performance (bandwidth, latency) and cost of the access network. The success factor is clear: the faster the network, the better the experience, and the better the experience, the higher the user adoption rate. To address performance the needs of IMS services, mobile operators are beginning to deploy high-speed Universal Mobile Telecommunications System (UMTS) RANs. But because UMTS networks require installation of an entirely new radio access infrastructure, cost constraints persist. In addition, UMTS is susceptible to higher signal loss inside buildings, so providing acceptable UMTS coverage within subscriber homes and offices will take additional time and add to deployment costs. Mobile operators are faced with the classic dilemma: investing in IMS infrastructure is costly and difficult without understanding the user acceptance for new services, and end user acceptance of these new services will be impacted by the performance of the radio network. With UMA, Wi-Fi and Broadband Supply the Answer There is some encouraging news, however. Because of their cost and performance advantages, broadband IP access and Wi-Fi are proving to be valuable complements to cellular radio access networks. Both broadband and Wi-Fi are established, proven, and popular high-bandwidth telecommunications technologies. Broadband access, for example, is reaching significant penetration rates in most developed countries due to heightened market competition. By the end of 2005, it is expected that over 46 million households in Western Europe and 41 million households in North America will be subscribed to DSL or cable broadband services. Market penetration of Wi-Fi is also accelerating rapidly due to strong interest in three market segments: • Businesses - Small to large enterprises are now deploying WLANs to increase employee productivity by eliminating the constraints of cable-based communication • Homes - Because of its convenience and mobility benefits, consumer Wi-Fi acceptance is increasing, and support is being built into most residential broadband modems 33
  • Tóth Balázs Viktor Wireless Home Gateway • Hot spots and hot zones - Many mobile operators are aggressively pursuing public WLAN deployment as consumers begin to expect and demand anytime, anywhere Internet access However, to move forward and reap the benefits of broadband and Wi-Fi, mobile operators require a standard that enables them to extend their mobile services over IP-based access networks. This is where the 3GPP Unlicensed Mobile Access (UMA) standard comes in. Originally developed by 15 leading companies in the mobile industry, UMA is now the 3GPP standard for enabling subscriber access to mobile services over Wi-Fi and broadband IP networks. With UMA, operators can now deliver high-performance mobile voice, data and IMS services over existing broadband and Wi-Fi connections in subscriber homes and offices as well as public hot spots. Figure 1 provides a high-level view of the UMA architecture, which is based upon a new UMA Network Controller (UNC) to extend mobile services over broadband access networks to UMA-enabled mobile devices. UMA was developed to allow mobile operators to turn existing WLANs into seamless extensions of their mobile networks, enabling subscribers to automatically roam and handover between the cellular radio network and a home, office or public WLAN. Many are aware that UMA enables seamless access to operator circuit services such as voice and Short Message Service (SMS) over Wi-Fi, but what is equaling compelling is how UMA also supports seamless access to operator packet services, specifically all IMS-based applications. In fact, UMA is the only defined standard available today that enables access to, and mobility of, IMS services 34
  • Tóth Balázs Viktor Wireless Home Gateway over Wi-Fi. As depicted in Figure 2, UMA provides all the needed functions for a mobile operator to provide access to packet/IMS services over broadband IP networks. With UMA, any IMS service available to a subscriber on the macro cellular network can now be accessed over a broadband IP access connection. UMA enables access to IMS services from any WLAN location. Additionaly, UMA manages the automatic handover of IMS sessions between the cellular network and WLANs, and visa versa. In effect, UMA enables true “Broadband IMS.” The 3GPP UMA standard enables mobile operators to offer the same advanced, revenuegenerating IMS-based applications over broadband IP access networks. With UMA, Wi-Fi becomes a viable indoor mobile access network solution, and is able to complement a mobile operator’s UMTS network deployment by providing high-performance, low-cost mobile voice, data and IMS services in places where subscribers spent most their time. How UMA Can Accelerate IMS Deployment With UMA, mobile operators can leverage the high-bandwidth, low-latency, and low-cost attributes of Wi-Fi access to accelerate the deployment of certain bandwidth intensive IMS services. As shown in Figure 3, UMA can provide significantly higher bandwidth with significantly less latency compared to other cellular data technologies, including UMTS. 35
  • Tóth Balázs Viktor Wireless Home Gateway Because of these cost and performance advantages, operators can look to leverage UMA technology to accelerate the deployment of certain IMS services. One advantage of the Kineto solution for UMA is its ability to notify IMS applications when subscribers are currently being serviced via a Wi-Fi connection, in effect making these services “UMA Aware.” As a result, the IMS service can adapt to the increased bandwidth available and provide subscribers with a richer, enhanced mobile experience. Figure 4 shows several examples as to how mobile data services could look to provide additional capabilities when subscribers were connected via UMA. 36
  • Tóth Balázs Viktor Wireless Home Gateway Conclusion Mobile operators are enthusiastic about the revenue generating potential of IMS services, but adoption challenges persist due to the throughput, latency, in-building coverage, and deployment cost limitations of the high speed cellular network technologies. Fortunately, the 3GPP UMA standard has emerged, which promotes faster development and deployment of IMS services by leveraging broadband Wi-Fi access networks. With UMA, mobile operators can leverage the cost and performance of IP to deliver high-speed IMS services to homes, offices, and hot spots. Using UMA, mobile operators can bring the mobile and IP broadband-wireless worlds together and increase the value of both. UMA adds value to the convenience and flexibility of mobile access networks by accelerating the cost-effective deployment of bandwidth-intensive streaming audio and video services such as interactive gaming, music streaming, video conferencing, and workgroup collaboration. UMA, in turn, broadens the appeal of broadband and wireless access networks by supporting seamless connectivity to advanced, location-specific mobile IMS services. 37
  • Tóth Balázs Viktor Wireless Home Gateway 11. Looking for FMC? Think UMA A recent opinion piece in Wireless Week declared that 2006 will mark the beginning of the fixed mobile convergence (FMC) era. That prediction should come true thanks to the emergence of a new 3GPP technology standard called unlicensed mobile access (UMA). Mobile operators will begin deploying UMA-compliant dual-mode GSM/Wi-Fi (802.11) handsets with the objective of offering true "one phone, one number" service. Although this initially may be viewed as complementary to existing wireline service, the long-term result could be mobile substitution of wireline service. The key components of a UMA solution are a UMA network controller (UNC) and a UMA compliant dual-mode (GSM/Wi-Fi) handset. The UNC is a new core mobile network element similar in functionality to a GSM base station controller (BSC). Where a BSC would interface with multiple base transceiver stations (BTS) in the GSM macro network, a UNC manages the UMA access network (UMAN) to provide mobile voice and data access via one or more WLANs. In addition, the UNC facilitates transparent roaming between networks using the licensed spectrum (GSM) and unlicensed spectrum (UMA). The goal is to deliver a seamless user experience no matter which access network the user is operating on, meaning GSM/GPRS core network services can be accessed via the UMAN and associated WLAN. This service transparency is essential to widespread acceptance of UMA technology. In addition to seamless roaming and handoff between GSM and UMA calls, several basic concepts are unique to UMA deployment. For example, the handset must be able to autonomously move from the Wi-Fi to GSM environment (rove out) and GSM to Wi-Fi environment (rove in) via proper network registration procedures. Similarly, the user should be able to set network preferences such as GSM preferred or GSM only, and Wi-Fi preferred or Wi- Fi only. THE MACRO EFFECT Mobile operators tend not to deploy new technologies unless they provide either a cost benefit or enhanced feature set/user experience. UMA technology delivers on both counts by providing improved voice quality and in-building coverage while offloading traffic from existing (higher cost) GSM radio networks. A typical GSM cell radius in suburban environments is around 2 km. This translates into an approximate coverage area of 12.5 km sq. In an ideal case, this could potentially cover more than 12,000 homes sitting on quarter-acre lots. Although this may sound like a lot, there's a catch: The macro network is not always engineered for full in-building coverage within a given cell. In fact, a 6dB to 10dB in-building penetration loss may reduce actual coverage by up to 70 percent, to less than 4,000 of the original 12,000 homes. The resulting reduction in radio access and voice quality ultimately will lead to a loss of potential revenue for the mobile operator. This is precisely where UMA technology can be a benefit to both operators and end-users. With a UMA-enabled dual-mode phone, the ability to offload traffic to localized Wi-Fi networks potentially can recover "lost" macro-network revenue. Not only do mobile operators not have to invest in additional base station equipment to increase coverage or in-building penetration (with 38
  • Tóth Balázs Viktor Wireless Home Gateway the associated spectrum and site maintenance costs), but they may not even have to provide the access points or Internet backhaul from individual homes due to the fact that this equipment is already in place and used for broadband Internet access. Of course, mobile operators may not realize any revenue from the cable or DSL backhaul, but they still benefit from any per- transaction downloads or mobile applications resident on the handset. Similarly, the end-user benefits from a common feature set with the GSM network and the capability to make and receive calls via a single phone number. FIXED-MOBILE CONVERGENCE Mobile operators have the distinct advantage of "owning the handset" in that it is an integral part of the wireless network; some would say they in turn "own the customer" in that they have substantial control over the end-user interface and feature set. From this viewpoint, UMA technology is an extension of FMC with the ultimate goal of mobile substitution in a converged world. A recent survey conducted by BrainJuicer, which targeted 1,000 customers in six European markets (France, Germany, Italy, Spain, Sweden and the United Kingdom), concluded that a UMA-enabled dual-mode phone would be positively received. In fact, if mobile calls in the home were priced the same as fixed line calls, then more than 50 percent of respondents said they would be likely to sign up for UMA service within 12 months. Furthermore, of the respondents who would probably buy the service, a third would make most or all of their calls at home on their mobile phone, a powerful case for mobile substitution. As initial deployments of UMA handsets begin with the movement toward "one phone, one number" service, the stage will be set for a more significant movement toward FMC. 39
  • Tóth Balázs Viktor Wireless Home Gateway 12. Nokia tests Unlicensed Mobile Access phone technology: Nokia launched yesterday its very first public test of Unlicensed Mobile Access (UMA), an innovative mobile communications technology that facilitates seamless handover between WiFi and cell networks. Nokia's dual-mode UMA phones automatically use VoIP when WiFi connectivity is available, and use GSM as a fallback when compatible WiFi networks are inaccessible. The device is capable of switching between networks during roaming as accessibility changes. Fifty families are participating in Nokia's UMA pilot program, which is being rolled out in the city of Oulu, Finland. The city, which is equipped with numerous publicly funded WiFi hotspots, is an ideal location for the experiment. Pilot program participants will use Nokia 6136 phones, which are equipped with dual-mode UMA components and are said to provide "smooth and seamless transitions" between quad-band GSM and 802.11b/g wireless. Support for seamless handover is what distinguishes Nokia's UMA technology from existing dual-mode solutions, like the BT Fusion service. Nokia's Senior Vice President of Mobile Phone Research and Development, Peter Ropke, believes that UMA is advantageous to network providers as well as consumers: "UMA technology truly brings simplicity in the usage of voice over IP. This pilot project is an important step forward in bringing functional UMA technology to the mass market. Both operators and consumers will be able to garner the benefits of this new technology." UMA technology provides unique advantages, in particular, it enables mobile phone network operators to expand service coverage at lower costs by using commodity wireless networking hardware rather than expensive cellular base stations. Despite the advantages, mobile network providers may perceive UMA as a threat since it could potentially cut into large portions of their revenue by moving cell traffic onto broadband lines. Nokia's pilot program, which is set to last for two months, could possibly be the prelude to widespread deployment of UMA technology—if mobile carriers can be convinced that customers' use of the phones won't result in a loss of revenue. 40
  • Tóth Balázs Viktor Wireless Home Gateway 13. Wifi telefon a Fonhoz A Fon egy olyan közösség, melynek tagjai szabadon hozzáférhetővé teszik a többi tag számára otthoni netüket, cserébe ők is szabadon használhatják a többi tag wifijét, akárhol is vannak a világon. A Skype kezdte meg ugyanis a nyomulást elsőként. A Fonnal már nem csak ingyen wifizhetünk a világban, de ingyentelefonálhatunk is. Pontosabban: ha Fon hotspot környékén vagyunk ingyen telefonálhatunk Skype-ra a Skypefonnal. Persze csak akkor van ingyen, ha Skype-ot csöngetünk. Ezt pedig eddig megtehettük laptopról is, ha Fon-hotspot közelébe értünk. Na de mennyivel egyszerűbb egy mobiltelefon forma készülékkel skype-olni, mint egy laptop+headset kombóval. A Skypefon persze elsősorban azért lehet sikeres, mert Európában a drasztikus roaming-díjszabás miatt eddig csak a gazdagok és az árérzéketlenek merték külföldön felvenni a mobiljukat. Most viszont, ha lemegyek nyaralni valahova délre, és haza akarok telefonálni, nincs más dolgom mint keresni egy Fon-hotspotot és megcsöngetni az otthoniak Skype-ját vagy rendes telefonját. Merthogy még az utóbbi is jobban megéri. 41
  • Tóth Balázs Viktor Wireless Home Gateway És még mindig nem indítottak pert a Fon ellen az ellenérdekelt piaci szereplők. Ki érti ezt? 42
  • Melléklet: • http://mobilitysolutions.pctel.com/ PCTEL's Mobility Solutions Group simplifies mobility across 3G, VoIP and Wi-Fi networks. Richly featured and easy-to-use, our portfolio of products serves consumers, enterprises, wireless access providers, distributors, integrators and manufacturers with a complete range of client, policy and performance solutions. • http://www.worldcell.com/ WorldCell is the leader in providing global wireless service solutions to Government, Enterprise, Industry as well as the international traveler. WorldCell provides solutions through a number of technologies, ranging from an international cell phone or satellite phone to the Roaming Service Bureau platform that mediates and translates different wireless standards for wireless network operators. • http://www.intel.com/technology/comms/roaming/index.htm Rengeteg pdf és Intel megvalósítás. • http://vowlan.wifinetnews.com/ T-Mobile Launches UMA in Seattle… • http://www.ivci.com/videoconferencing_tandberg_3g_gateway.html Konkrét termék és sok szép ábra. http://www.cisco.com/en/US/netsol/ns341/ns396/ns177/ns278/networking_solutions_solut ion_category.htm Rengeteg leírás, műszaki megoldások is. Sok szép ábra!