Will Wi-Max make Wi-Fi obsolete?

Q: What is Wi-Max? Is it going to make my investment in Wi-Fi obsolete?

Deval, Atlanta

A: Don’t fret about your Wi-Fi investment. You will continue to reap the benefits of your current WLAN infrastructure for many years to come. You may even increase those benefits by extending your wireless network as Wi-Max becomes more established. But first you need to understand Wi-Max.

Wi-Max, short for ‘Worldwide Interoperability for Microwave Access,’ refers to any broadband wireless access network based on the new IEEE 802.16 standard. This specification covers both the Media Access Control (MAC) and the physical (PHY) layers for fixed systems employing a point-to-multipoint (PMP) architecture operating between 2 GHz and 66 GHz. Wi-Max also refers to the technical working group organized to establish conformance and testing standards for the 802.16 technology, to promote vendor interoperability.

Wi-Max is capable of transmitting network signals covering in excess of 30 miles of linear service area, which is much greater than Wi-Fi’s coverage of several thousand square feet. It provides shared data rates of up to 70M bit/sec., which is also greater than Wi-Fi’s theoretical high of 54M bit/sec (for 802.11g). Like Wi-Fi, it is divided into two groups by frequency: 2-11 GHz and 10-66 GHz. This is because PHY considerations require line of sight transmission for higher frequencies, but not for lower frequencies. Its MAC was flexibly designed to carry any transport protocol like Ethernet, Internet Protocol, and ATM.

So with all these benefits and flexibility, why can’t Wi-Max replace Wi-Fi? Because of other key differentiations, most notably that Wi-Max uses fixed network infrastructure and requires relatively high-gain antennas (about the size of a small laptop). As a result, Wi-Max is a non-mobile high-speed wireless network that connects one fixed node to several other fixed nodes, like a radio tower communicating with several antennae installed on top of buildings.

This means Wi-Max is ideally suited to replace the costly installation/service of short-distance dedicated enterprise T-1 lines. Thus, Wi-Max will integrate with your existing WLAN by wirelessly connecting several buildings within an enterprise campus WAN. The Wi-Max network will connect with your firewall/router, LAN, and WLAN just like a T-1 or DSL line does. Other Wi-Max applications include delivering Ethernet access to Wi-Fi hot-spots and last mile broadband access for home cable or DSL service.

Wi-Max could make high-speed Internet access much more widespread by delivering wireless service to regions currently lacking wired infrastructure, especially rural areas. It’s possible that Wi-Max could threaten 3G or other wide-area cellular technologies by speeding up the dissemination of cheap Wi-Fi hot-spot service on ubiquitous citywide levels. Eventually, these two technologies will grow into inseparable components of the truly wireless network: Wi-Max will deliver wireless Ethernet across large areas connecting smaller WLAN systems, while Wi-Fi will provide wireless access to small mobile devices within these WLAN networks. But one thing is certain - Wi-Max will not replace Wi-Fi.

Learn more about this topic

Researchers see trouble ahead for WLAN performance

IDG News Service, 07/31/03

How users share 802.11 channels

Network World Wireless in the Enterprise Newsletter, 10/01/03

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