How wimax works

Think about how you access internet today. There are basically three different options:

Broadband access in your home, you have either a DSL or cable modem at office your company may be using a T1 or a T3 line.

Wifi access in your home you may have set up a wifi router that lets you surf the web while you louge with your laptop. On the road, you can find wifi hot spots in restaurants, hotels. Coffee shops and libraries.

Dial-up access if you are still using dial-up, chances are that either broadband access is not available, or you think that broadband access is too expensive.

The main problems whit broadband access are that it is pretty expensive and it doesn’t reach all areas. The main problem with wifi access is that hot spots are very small, so coverage is sparse.

What if there were a new technology that solved all of these problems? This new technology would provide:

The high speed of broadbond service

Wireless rather than wired access, so it would be a lot less expensive than cable or dsl and much easier to extend to suburban rural areas

Broad coverage like the cell phone network instead of small wifi hotspots.

This system is actually coming into being right now, and it is called wimax. Wimax is short for world wide interoperability for microwave access. And it also goes by the IEEE name 802.16.

Wimax has the potential to do to broadband internet access what cell phones have done to phone access. In the same way that many people have given up their "land line" in favor of cell phones. Wimax could replace cable and dsl services, providing universal internet access just about anywhere you go. Wimax will also be as pailless as wifi turning your computer on will automatically connect you to the closest available wimax amenna.

In this article, well find out how wimax works. What engineers are doing to make it better and what it could mean for the future of wireless internet.

Wimax wireless network

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 3000 square miles (~8000 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.

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 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 3000 square miles, is what allows wimax to what this points out is that wimax actually can provide two forms of wireless service:

There is the non line of sight wifi sort of service where a small antenna on your computer connect to the tower. In this mode, wimax uses a lower frequency range 2 GHz to 11 GHz (similar to wifi) lower wavelength transmissions are not as easily disrupted by physical obstructions they are better able to diffract, or bend, around obstacles.

There is line of sight service where a fixed dish antenna points straight at the more stable so its able to send a lot of data with fewer errors. Line of sight transmissions use higher frequencies, with ranges reaching a possible 66 GHz. At higher frequencies, there is less interference and lots more bandwidth.

Wifi style access will be limited to a 4 to 6 mile radius (perhaps 25 square miles or 65 square km of coverage, which is similar in range to a cellphone zone). Through the stronger line of sight antennas, the wimax transmitting station would send data to wimax enabled computer or routers set up within the transmitters 30 mile radius (2800 square miles or 9300 square km of coverage). This is what allows wimax to achieve its maximum range. the final step in the area network scale is the global area network (GAN).

The proposal for GAN is IEEE 802.20. a true GAN would work a lot like today cell phone networks, with users able to travel across the country and still have access to the network the whole time. this network would have enough bandwidth to offer internet access comparable to cable modem service, but it would be accessible to mobile, always connected devices like laptops or next generation cell phone.

 نوشته شده توسط محمد قاری در چهارشنبه 89/9/17 و ساعت 2:34 عصر | نظرات دیگران()