Saturday, January 04, 2003
WLL vs Cellular
There is considerable confusion around Reliance Infocomm's announcement (new announcement offering the sky) of Wireless in Local Loop (WLL) technology. Let's try to understand what's going on.
What is WLL?
- WLL is a system that connects subscribers to the public switched telephone network (PSTN) using radio signals as a substitute for traditional copper wire for all or part of the connection between the subscriber and the switch (at the telephone office). This includes cordless access systems, proprietary fixed radio access, and fixed cellular systems.
- Because there are no definitive WLL standards, vendors are faced with a bewildering choice of technologies. Although GSM (the cellular technology used in India, Europe and 65% of the world) currently dominates mobile digital cellular, there has been little activity in using GSM as a WLL platform. Since GSM's architecture was designed to handle international roaming, it carries a large amount of overhead that makes it unwieldy and costly for WLL applications.
- CDMA, another cellular standard used primarily in US, appears to be the standard best suited for WLL applications. CDMA employs a spread-spectrum modulation technique in which a wide range of frequency is used for transmission and the system's low-power signal is spread across wide-frequency bands. It offers higher capacity than the other digital standards (10 to 15 times greater than analog cellular), relatively high-quality voice, and a high level of privacy. The main disadvantage of CDMA is that it is only now beginning to be deployed on a wide scale.
Summary: WLL includes all wireless technologies that can replace copper-wire telephone connections. They also include cellular technologies. CDMA is the most popular technology today for implementing WLL networks.
The Reliance strategem
- Reliance Infocomm is offering WLL services in conjunction with its basic telephony offering.
- Unlike cellular telephone services, WLL services can only be provided in a 30 (or is it 35?) km radius.
- Cellular players need to pay fees to connect to regular PSTN (land-line telephone network). WLL players do not have to pay such connectivity fees.
- Reliance wants to use its new nationwide network and build a 'connected' WLL network on top of it.
Pitfalls, questions etc
So the questions are: Is this technology really cheaper/better? How will roaming/connectivity work with Reliance Infocomm's WLL?
- The general feeling is that many of the ancillary expenses of deploying and maintaining WLL technology are not taken into account by new service providers. This is a mistake that is usually not made by wireline providers, who understand well that the cost of provisioning service to a customer consists of elements such as switching, outside plant, personnel, and operations.
- One important economic consideration is that a WLL network can be deployed very quickly: Activating a system within 90 to 120 days is feasible.
- I don't understand the roaming features of this network. If you do, please drop me a line.
Summary: WLL isn't going to change the face of wireless telephony in India. If the Reliance model works, cellular operators will also lobby for lower tariffs on connecitivity to PSTN. But the Reliance model may itself fail in one or more of three areas - cost, land-line penetration, or even roaming which GSM-based cellular telephony players provide near-seamlessly today.