GSM on 450 MHz – bringing wireless services to the rural parts of our globe

In September 2005 a magic milestone was reached in telecom history with the addition of the 2^nd billionth wireless subscriber. By the end of 2005 estimations say that the number of mobile subscriptions will be equal to a third of the planets population. Over 75% of these 2 billion subscribers use GSM, this is by far the dominant cellular technology, adding more than 30 million subscriptions to the installed base per month.

Yet two thirds of the world’s population has no mobile subscription. A majority of these 4 billion people can be found in emerging markets in Asia, Africa and Latin America. Roughly 50% of the people without a mobile subscription are living in areas that are already covered with at least one mobile operator, but they have still not invested in a subscription. Addressing this segment is quite straightforward considering the capacity potential of modern wireless infrastructure and the economies of scale of GSM providing entry-level phones in the price range of 20-30 USD. The other segment – the 2 billion people living outside existing mobile network coverage – are not that easily addressed considering the substantial investments needed to expand coverage. Especially considering that these areas are often remote and lack utility lines and transmission backbone. It is in these areas where GSM 450 comes into play.

Operation in the 450MHz 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 450 offers more efficient coverage than the higher frequency variants of GSM. This means that operators need to deploy fewer sites; GSM 450 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. Furthermore, when a GSM network infrastructure already exists, GSM 450 can reduce network investment costs even further, since most of the installed system can be reused.

The radio coverage area for a GSM 450 BTS site will exceed the radio coverage provided by both GSM900 BTS and GSM 1800 BTS sites. Due to the predicted radio coverage that will be available with the implementation of GSM 450 radio site, the extended cell feature will be an integral part of the new frequency.  The enhancement of the extended cell feature will accommodate ranges of between 70 and 140 km.  Even more than 200 Km can be achieved using several timeslots if so desired.

If the entire infrastructure cost benefits are based on large coverage and the large coverage are resulting from transmitting on a low frequency band – why use GSM and not CDMA? (Where 450 MHz products have existed fore a while)

There are three important reasons to why GSM on 450 MHz are superior to any other access technology:

1. Economy of scale – with >600 million GSM phones produced annually the average sales prices are less than 50% of the cheapest CDMA phones (30 USD compared to 70 USD) – especially when there will be almost no cost penalty of adding 450 MHz to a tri or quad band GSM chipset

2. Global roaming – With a quad band phone including GSM 450/900/1800/1900 the subscriber will be able to call from any country of the world, except Korea and Japan. Furthermore the GSM infrastructure can be re-used, hence limiting the GSM 450 investments to sites where GSM coverage is extended.

3. Wireless data – GSM 450 will be able to dynamically offer voice and data services (up to 300 kbps), without needing to dedicate chunks of the spectrum to data only transmission.

All together this means delivering 100% flexibility to the voice/data business model, significantly reducing the risk as well as the cost when expanding coverage into new areas. GSM 450 benefits in the huge GSM footprint Worldwide and 450 can be a fallback solution for GSM 850/900/1800/1900

Ericsson and Nokia terminals jointly announced their ambitions to expand their GSM portfolios into the GSM450 MHz band. Ericsson said they would add GSM 450 as an option in their base station system (RBS2000 product line) and Nokia by developing a GSM mobile phone supporting 450 MHz in addition to the conventional bands.  

With the leading companies in wireless telephony expanding the portfolio with GSM 450, mobile access will be available for new markets and operators. This will particularly help to bring mobile services to remote areas previously considered less feasible to cover. Better coverage with lower operating costs is one result of the new technology. Supplementing fixed line is also an advantage in rural areas.

As Ulf Ewaldsson, Vice President and head of GSM at Ericsson says: "We believe that GSM will be the leading access technology supporting mass-market services for a long time to come. GSM 450 is the next logical step to provide service to emerging growth markets.“

Javier Camargo
VP Polícies and regulations in Radiocommunications
Ericsson Administrative Services
Mexico
E-Mail: [email protected]