How Wimax Work?

In practical terms, WiMAX would operate similar to WiFi but at higher speeds, over greater distances and for a greater number of users. WiMAX could potentially erase the suburban and rural blackout areas that currently have no broadband Internet access because phone and cable companies have not yet run the necessary wires to those remote locations.

A WiMAX system consists of two parts:

- A WiMAX tower, similar in concept to a cell-phone tower - A single WiMAX tower can provide coverage to a very large area -- as big as 3,000 square miles (~8,000 square km).

- A WiMAX receiver - The receiver and antenna could be a small box or PCMCIA card, or they could be built into a laptop the way WiFi access is today. built into a laptop the way WiFi access is today.

A WiMAX tower station can connect directly to the Internet using a high-bandwidth, wired connection (for example, a T3 line). It can also connect to another WiMAX tower using a line-of-sight, microwave link.

This connection to a second tower (often referred to as a backhaul), along with the ability of a single tower to cover up to 3,000 square miles, is what allows WiMAX to provide coverage to remote rural areas.

SDIC Card

What RF Frequencies does WiMAX work in?

The most recent versions of both WiMAX standards in 802.16 cover spectrum ranges from at least the 2 GHz range through the 66 GHz range. This is an enormous spectrum range.

However, the practical market considerations of the Forum members dictated that the first product profiles focus on spectrum ranges that offered Forum vendors the most utility and sales potential.

The International standard of 3.5 GHz spectrum will be the first to enjoy WiMAX products. The US license free spectrum at 5.8 GHz should receive some products, but likely will be the last supported.

Licensed spectrum at 2.5 GHz used both domestically in the US and fairly widely abroad will be the second frequency chosen for interoperability testing. There is already a significant amount of precursor product being shipped at all three frequencies. Air interface testing has certified products from many companies. The more enhanced QOS and optional elements testing is up next. As is the interoperability testing for Mobile WiMAX.

The technology appears easily extensible to lower frequencies including the valuable 700 MHz spectrum range. More likely near term frequencies likely to be supported in future product profiles include the 2.3 GHz range (used in Korea and the US) as well as the new 4.9 GHz public safety band (sometimes described as a Homeland security band). The 700 MHz range, partly due to Flarion’s technology being available in this spectrum, may receive more attention. The 900 MHz unlicensed bands are unlikely to receive Forum attention for a long time if ever.

The largest block of frequencies ever auction occurred in the summer of 2006 with the AWS auction from the FCC. This spectrum was split with the bulk being at 1.7 GHz and the rest at 2.1 GHz. Expect to see the Forum address this on an individual vendor basis initially with adapted WiMAX solutions. The potential of the spectrum range is enormous and will almost certainly be met with products from the WiMAX community.

by Michael Wolleben — last modified 2007-03-19 12:56 PM
Source: http://www.wimax.com/education/faq/faq47