GSM 400 and NMT
Nokia, Ericsson, ETSI, and the EU are all pushing GSM as the upgrade path for NMT operators. This advocacy piece by Ericsson has been released just as cdmaOne tests on NMT start in Hungary. Hungary is trying to get into the EU and will be expected to conform to ETSI standards.
e-topics.com
GSA/ GSM 400 -- A new cellular dimension
[M2 Communications, Inc.]
M2 PRESSWIRE via NewsEdge Corporation : A new frequency band is now being standardised by the European Telecommunications Standards Institute (ETSI) for GSM - 400 MHz - a band that brings access to this world-leading standard for NMT 450 operators, as well as offering a coverage bonus effect to current GSM operators worldwide. GSM 400 will evolve with the core GSM specification and will include seamless roaming with other GSM bands.
The introduction of the new 400 MHz frequency band will further leverage the success of global GSM, which so far has been established through the current 900MHz, 1800MHz and 1900MHz bands.
Article re-printed with kind permission from Eastern Europe Wireless Communications Vol 2 No 4 February/March 2000 Eastern European Wireless Communications is published by Kadium Ltd, United Kingdom.
By Hans Bendes, Ericsson Radio Systems and Alan Hadden, President, GSA.
In April 1998, it was agreed that a Digital Interest Group (DIG) would be formed to investigate the migration options open to NMT 450 operators. During 1998, the DIG prepared a detailed Requirement Specification with which vendors could comply. The DIG group investigated three possible technologies as potential digital versions of NMT and, in October 1999, the results of the investigations were presented with the majority of the NMT MoU operators expressing their preference for the GSM 400 solution.
Market Potential Worldwide, there were an estimated 213 million GSM users by the end of September 1999 - equivalent to over 65% of the world's digital mobile phone users (source GSM MoU and EMC). GSM is the fastest-growing mobile standard, increasing by almost four new subscribers every second! Until now, this success has been built on GSM services at 900MHz, 1800MHz and 1900MHz. GSM 400 will now offer existing and new GSM operators greater opportunities to provide cost-effective communications and extend services to a wider number of users.
Cost-Efficient Coverage Operation in the 400MHz band offers an advantage in coverage over other systems operating in higher frequencies, as a signal attenuates less at lower frequencies. This means less investment costs for the operator, as fewer cell sites are required to cover rural and coastal areas and highways. With its inherent better propagation characteristics, GSM 400 offers more efficient coverage than the higher frequency variants of GSM. This means that operators need to deploy fewer sites; GSM 400 covers the same area as GSM 1800 with a fifth of the number of sites and the same area as GSM 900 with half the amount of sites. The potential cell range is up to 120 km. Furthermore, where a GSM network infrastructure already exists, much of it can be reused by GSM 400, reducing network investment costs further.
The requirement for fewer base stations also reduces installation time, which in turn leads to reduced time-to-market, enabling new operators to start earning revenue and capture market share more quickly. The increased coverage is also more attractive to users, which both encourages further subscribers to sign up and increases loyalty among existing subscribers.
Key Factors for NMT 450 Ooperators Going Digital
It is inevitable that the first European analogue cellular standard, NMT 450, will evolve into a digital communications standard within the next two or three years. Existing spectrum limitations and the pressing demand to make cellular systems in the 400-MHz band competitive in terms of quality, availability of attractive terminals and value-added features, will be the main drivers behind the transition of the existing NMT 450 systems to the new digital standard. For countries that are looking to increase the take-up of digital services, the migration from NMT 450 to GSM 400 offers substantial advantages. The extensive service capabilities of GSM will allow operators to differentiate their services to a greater extent than analogue systems. These services include worldwide roaming and secure calling via GSM SIM card and data services. The need for operators to attract investment to expand their networks is also a key driver behind the move from analogue to digital services. Investors will clearly choose to invest in future-proof technologies that can demonstrate a defined evolution path towards third generation multimedia services.
GSM 400 Facts Frequency Allocation
GSM 450 Band: 450.4 - 457.6 MHz uplink 460.4 - 467.6 MHz downlink
GSM 480 Band (ext.): 478.8 - 486 MHz uplink 488.8 - 496 MHz downlink
Frequency Spectrum:7 MHz Duplex
Seperation:10 MHz Carrier Spacing:200 kHz Coverage, Extended Range:Up to 120km Supports fragmented usage of the frequency band
Why GSM 400? The popularity of GSM means it benefits from the significant system, service and application development effort of a large number of vendors and operators around the world.
GSM 400 enables operators to become part of this global community at a lower cost than previously possible. The benefits span from initial service concept right through to services delivery. Cost of ownership is low, because the widespread deployment of GSM equipment all over the world has led to economies of scale. Most important of all, GSM offers a vast pool of expertise from which operators can draw. The sheer number of GSM networks that have already been installed means that roll-out time is reduced, with increasing automation and standardisation of network elements.
For operators already running GSM networks at the 900 and 1800 frequency bands, GSM 400 offers a cost-effective addition to their existing operations.
Because fewer cell sites have to be constructed for a GSM 400 network, expansion costs are lower than for GSM 900 and 1800. Additionally, much of the existing GSM infrastructure can be used when running parallel networks, reducing costs and lessening the environmental impact. Hence operators receive a more rapid return on their investment. The reduced cost of network infrastructure for GSM 400 is particularly pertinent to operators introducing services to rural areas, which have lower subscriber concentrations and hence offer less potential for generating income. Investment in GSM 400 can, therefore, be justified more readily than in a network relying on a more extensive infrastructure.
A seamless handover to higher frequency GSM cells can be made when moving between rural areas and urban ones.
Operators can, therefore, offer a GSM network which provides capacity in urban areas by running GSM 900 or 1800, and coverage in rural areas by running GSM 400.
GSM 400 Today
The GSM 400 standard is now being finalised by the standardisation body ETSI, which will release a GSM 400 specification as part of its ETSI/SMG GSM99 specification. GSM 400 is expected to become commercially available during 2001.
In the meantime, GSM 400 is attracting support from many suppliers and operators, with field tests already having begun. During September 1999, the first official mobile call on the GSM 400 frequency was made during a GSA conference held in Budapest.
Future Proof
With GSM's clear evolution path to 3G, operators can select GSM 400 safe in the knowledge that it is a solid foundation for the future, being a part of the GSM family.
For instance, the imminent introduction of General Packet Radio Service (GPRS) in GSM will help to create a mass market for data services.
Beyond GPRS, Enhanced Data rates for Global Evolution (EDGE) will allow operators to support 3G services within the GSM environment, including multimedia and location-based services. GSM 400 will also ease the foreseen coverage shortcomings of high-speed GSM data transmission using EDGE.
Operators can use the same cell structure for EDGE on GSM 400 as on GSM 900, reducing the cost outlay for the additional cell sites that the introduction of EDGE would otherwise require. Depending on the operator's strategy for providing high-speed data services, GSM 400 allows both GSM 900 and GSM 1800 operators to trim their costs of operating sites covering rural and suburban areas.
Unweildy Co-existence at 450 MHz
Technically, GSM 400 and NMT 450 can run in parallel on the 450MHz band. This will be the standard process that many operators follow during the migration from NMT to GSM.
In the long run, however, the limited availability of spectrum frequency in most countries will make running both networks on a long-term basis impractical, since all capacity available will be required to run a full service.
As a result, operators will eventually need to close down their 450 networks to run GSM 400 networks successfully.
About the Authors
Hans Bendes is Strategic Product Manager at Ericsson Radio Systems AB, Stockholm, Sweden. He has been with Ericsson for 9 years working with different cellular systems, especially with radio applications.
Alan Hadden became the first President of the Global Mobile Suppliers Association in 1998 and has more than 12 years' experience in senior positions in the manufacturing, regulatory, operator and consultative sectors of the mobile communications industry.
About the GSA
GSA - the Global Mobile Suppliers Association - is the forum for the GSM supplier industry. Its members include the leading suppliers of GSM products, systems and services from around the world. GSA has two main objectives:
--to strengthen the promotion of GSM world-wide in new and existing markets, thus ensuring GSM's continual growth as the de facto world sigital cellularstandard;
--to promote the evolution of GSM as the platform for delivery of third generation (3G) multimedia services.
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