universal mobile access

UNIVERSAL MOBILE ACCESS

ABSTRACT


The idea of using unlicensed radio in mobile handsets for interconnecting with the core mobile network is interesting both technically and economically. The installed base of wireless access points has increased through the emergence of reasonable priced and easy to use WLAN equipment to accessing Internet with broadband connections. The use of unlicensed radio spectrums is expected to give economical benefits both for the end users and to operators. The wireless industry has been searching for low-cost licensed indoor coverage solutions since the beginning of mobile networks. Unfortunately, the bulk of this opportunity (i.e. residential environments) has been beyond the addressable market for cost and operational reasons.

UMA is the 3rd Generation Partnership Project (3GPP) global standard for subscriber access to mobile circuit, packet and IMS-based services over any IP-based access network, including the Internet. With UMA, mobile operators can now leverage the cost and performance advantages of IP access technologies (DSL, Cable, Wi-Fi...) to deliver high-quality, low-cost mobile voice and data services in the locations where subscribers spend most of their time - the home and office. Fundamentally, UMA provides a standard, scalable, secure IP interface into the core service network of mobile operators.Based on a literature study, this paper depicts the current situation of UMA technology and its influence for businesses of operators and telecomm vendors as well as the benefits for the users.

Key Words:
 UMA
 GSM
 GPRS
 802.11
 Fixed-Mobile Convergence
 IMS
 WI-FI
 SIP
 UNC


1. INTRODUCTION

Many users, at least outside of Finland, still have a fixed line telephone at home and in the office in addition to a mobile phone. Most of them would prefer just one mobile device, which could provide all needed communications services without needing to worry about what network is available. The unification of fixed and mobile devices as well as their services is often called with term fixed-mobile convergence (FMC). In this paper we look how UMA technology is enabling this kind of evolution. Also we briefly look the status of the other related standards.

FMC is an important issue for many other stakeholders than end users. We discuss the influences of UMA for different players like operators and vendors. Descriptions of enabled end user services and a successful pilot are given. In the end of the paper we conclude how we see the situation of UMA today.

Figure 1: UMA compared to standard GSM

Unlicensed Mobile Access (UMA) is a technology that connects regular unlicensed wireless networks to GSM networks. The wireless networks are currently limited to Bluetooth and 802.11(wi-fi), but soon others will follow. UMA defines a UMA Network Controller, UNC, which connects to the mobile network using standard A/Gb connections, replacing GSM’s Base Station Controller (BSC). All GSM services are tunneled through the IP pipe, including GPRS. Of course, data transfer speeds are quite a lot faster than with cellular access (UMA Technology).

Calls and data connections feature seamless handover between cellular and UMA, as well as roaming back to cellular if UMA isn’t available. UMA enabled phones can use any standard 802.11(wi-fi) access point for connection, though naturally the AP must provide network access for the user. The network features multiple UNCs, one of which is a default one. The default UNC chooses another UNC for the mobile terminal if needed, based on the network topology.

2.UMA-HOW IT WORKS:
By deploying UMA technology, service providers can enable subscribers to roam and handover between cellular networks and public and private unlicensed wireless networks using dual-mode mobile handsets. With UMA, subscribers receive a consistent user experience for their mobile voice and data services as they transition between networks.
In order to promote the widespread adoption of UMA technology, a number of leading companies within the wireless industry have jointly developed a set of open specifications. These specifications are available through this Web site, and may be used by vendors and carriers of wireless communications systems and applications to develop and deploy interoperable solutions.In addition to developing and maintaining the initial specifications, the participating companies are actively working with the 3GPP standards organization to use the specifications as the basis for the development of a formal standard.
2.1 How UMA Technology Works

1. A mobile subscriber with a UMA-enabled, dual-mode handset moves within range of an unlicensed wireless network to which the handset is allowed to connect.
2. Upon connecting, the handset contacts the UMA Network Controller (UNC) over the broadband IP access network to be authenticated and authorized to access GSM voice and GPRS data services via the unlicensed wireless network.
3. If approved, the subscriber’s current location information stored in the core network is updated, and from that point on all mobile voice and data traffic is routed to the handset via the Unlicensed Mobile Access Network (UMAN) rather than the cellular radio access network (RAN).
4. ROAMING: When a UMA-enabled subscriber moves outside the range of an unlicensed wireless network to which they are connected, the UNC and handset facilitate roaming back to the licensed outdoor network. This roaming process is completely transparent to the subscriber.
b:handover: If a subscriber is on an active GSM voice call or GPRS data session when they come within range (or out of range) of an unlicensed wireless network, that voice call or data session can automatically handover between access networks with no discernable service interruption. Handovers are completely transparent to the subscriber.
2.2UMA-NETWORK:

UMA-enabled Dual-Mode Wi-Fi Handsets: By far the most well-known UMA service is dual-mode cellular/Wi-Fi handsets (DMH), which enables operators to provide high-performance, low-cost mobile services to subscribers when in range of a home, office or public Wi-Fi network. With a UMA-enabled dual-mode Wi-Fi handset, subscribers can automatically roam and handover between cellular and Wi-Fi access, receiving a consistent set of services as they transition between networks.

UMA-enabled Terminal Adaptors: The market for broadband telephony service has increased dramatically over the last twelve months. At the end of 2006, Vonage Holdings alone had more than 2 million subscribers paying between $15 and $25 per month for a telephone service delivered over existing broadband access connections.

UMA-enabled Soft mobiles: Connecting laptops to broadband access at hotels and Wi-Fi hot spots has become a standard part of everyday life, particularly for international business travelers. In addition, many travelers are beginning to utilize laptops and broadband connections for the purpose of voice communications. Rather than using mobile phones to make calls and pay significant roaming fees, they are turning to PC-based soft-phones and VoIP services when making international calls. This represents a significant threat and opportunity for mobile operators.

3.MEDIA UMA USE:
IEEE 802.11, commonly known by the brand Wi-Fi, denotes a set of Wireless LAN standards developed by working group 11 of the IEEE LAN/MAN Standards Committee (IEEE 802). Wi-Fi technologies have gone through several generations since their inception in 1997. Wi-Fi is supported to different extents under Microsoft Windows, Apple Mac OS and open source Unix and Linux operating systems.
BLUETOOTH is an industrial specification for wireless personal area networks (PANs). Bluetooth provides a way to connect and exchange information between devices such as mobile phones, laptops, PCs, printers, digital cameras, and video game consoles over a secure, globally unlicensed short-range radio frequency. The Bluetooth specifications are developed and licensed by the Bluetooth Special Interest Group.
4.ADVANTAGES:
For carriers:
In addition, GAN relieves congestion on the GSM or UMTS spectrum by removing common types of calls and routing them to the operator via the relatively low cost Internet
Some other operators also run networks of 802.11 hotspots, such as T-Mobile. They will be able to leverage these hotspots to create more capacity and better coverage in many populous areas.
Subscribers, not the network, pay directly for much of the costs associated with the service. They pay for a connection to the Internet, effectively paying the expensive part of the cost of routing calls from their location.
For subscribers:
Subscribers do not rely on their operator's ability to roll out towers and coverage, allowing them to fix some types of coverage blackspot themselves (such as in the home or office.)
GAN is currently the only commercial technology available that combines GSM and Wi-Fi into a service that uses a single number, a single handset, single set of services and a single phone directory for all calls.
DISADVANTAGES
Handsets must support Wi-Fi network access which requires additional space, power and complexity and may affect the size, weight nd battery performance of the phone.
Compared to completely free Wi-Fi VoIP services such as Skype, the fact that GAN is an extension of the cellular network and connects to the carrier's servers practically means that carriers will charge for this service in one way or another. GAN is designed around connecting directly to an existing 2/2.5G GSM network. As such it is only suitable for network operators who have an existing GSM network. For operators such as '3' in the UK this is not the case. To address the issue a development called EGAN is under way in 3GPP
5.END USER SERVICES

UMA technology can benefit both consumers and enterprises with positive user experience and cost savings. Savings may come though owning and using only a single phone and lower service prices. Mobile network access though WLAN and broadband connection is providing bigger bandwidth than GPRS, EDGE or UMTS. Especially this will greatly complement to GSM network users.
UMA technology provides also improved mobile phone indoor coverage especially in North America where only limited coverage is provided in many residential areas. Extended location based services are possible since the unlicensed access point is identified together with the GERAN or UTRAN cell. The handset could for example inform the street address during its registration request to the UNC alias GAN controller (GANC). The more accurate geographic location can then be used for instance in emergency situations (Ericsson Review No. 2 2005).

6. VENDOR STRATEGIES

The first service is launched by BT fusion –British Telecom Fusion using NOKIA,MOTORLO,SAMSUNG on WI-FI..The initial aim for the vendors of UMA forum was to establish standardized technology to ensure cooperation in commercialization stage of the technology, because it was crucial to provide compatibility between all manufacturers’ products and prevent the emergence of multiple competing standards (Schilling 2005).

Telecomm vendors eagerly market their FMC solutions for operators. Handset vendors tend to build support for multi-radio and multi-access terminals enabling different access methods including WLAN. For example Nokia has announced that it will aim supporting both UMA and what they call Native IP access to be used with IMS (Nokia Corporation 2005). Some vendors develop their own network equipment to support UMA while some others have made strategic decision to offer them trough a collaboration partner, see
Table 1: Announced UMA network vendor solutions (InCode 2005)
Vendor UMA solution
Alcatel Together with Spatial
Ericsson Own UNC
Kineto Wireless Own UNC
Motorola Kineto’s software, possibly own hardware
Nokia Resells Kineto’s UNC
Table 2: Announced handset vendors supporting UMA (InCode 2005)

Vendor Model and availability
BenQ P50 Pocket PC, 2005
Chi Mei No information
LG Electronics CL 400, 2005
Motorola V560, Razr and A910, 2005-2006
Nokia 6136, 2006
Samsung No information

7:CONCLUSION

UMA enabled handsets will be available in greater numbers very soon, complete with a very low power consuming 802.11g WLAN chips. It is unlikely to see any reasonable growth for the UMA Bluetooth markets, since the range is limited and access points aren’t available (Philips 2005).

Still, it is not clear whether UMA will be a big hit or not. The operators need to have enough customers with UMA enabled handsets so that their investments to the network side would be profitable. In some countries, such as the United States, UMA is more attractive than in others, due to the worse existing cell coverage. Also, the pricing point is critical for the customers, so that they are willing to buy a UMA enabled mobile handset as well as have the additional radios switched on, sacrificing some standby time. We estimate that UMA in its current form will be properly in use, if it ever will, in around 2 years.

UMA technology seems to suite well for regular mobile network operators in their long-term mobile network evolution and it has a significant time-to-market advantage over VCC Some new fixed-line operators such as cable-TV and VoIP providers are likely to target to IMS directly without UMA. Since IMS with VCC provides a substitute for UMA, the technology choice of operators plays a key role in how UMA is diffused. We believe that all related standard technologies will be used side by side within future mobile networks, though analyzing the overlaps between UMA and I-WLAN would need separate studies and knowledge about anticipated convergence between VCC and the most advanced scenarios of I-WLAN (InCode 2006)

9.REFERENCES

1.UMA Technology. http://www.umatechnology.org/overview/index.htm, referenced on 15th April 2006.
2.MOBILETODAY
3.WWW.MOBILE PHONE DEVELOPMENT.COM
4.InCode 2006. http://www.incodewireless.com/media/whitepapers/2006/UMAsRole-(Jan-2006).pdf, referenced on 16th April 2006.
5.InCode 2005. http://www.incodewireless.com/media/whitepapers/2005/WP_UMAConvergence-(Sep-2005).pdf, referenced on 16th April 2006.