Computer And Technologies

Computer And Technologies: WiMAX (IEEE 802.16e) Advantages and Disadvantages!

Wednesday, 22 April 2009

WiMAX (IEEE 802.16e) Advantages and Disadvantages!

What are the disadvantages or shortfalls of WiMAX network for a corporate network, requiring high capacity and total control over the network? Should Point to point be a better option?

Here we will talk something about disadvantages of WiMAX technology. Common misconception is that WiMAX can offer 70 Mbps in range of 70 miles (113 kilometers) with moving stations. But in practice situation is very different. It is true only in ideal circumstances with only one recipient. You could have with line-of-sight (optical visibility) speed of 10 Mbps at 10 kilometers. In urban enviroment (without optical visibility) users can have 10 Mbps at 2 kilometers. If users are moving, the speed can drop significantly. Bandwidth is shared between users in given radio sector, so if there are many users in one sector, they will have reduced speed. Users could have 2, 4, 6, 8, or 10 Mbps of shared bandwidth. The biggest disadvantage of WiMAX is still much bigger installation cost and also operational cost.So let's put on paper WiMAX advantages and disadvantages.


1) Single station can serve hundreds of users.
2) Much faster deployment of new users comparing to wired networks.
3) Speed of 10Mbps at 10 kilometers with line-of-sight.
4) It is standardized, and the same frequency equipment should work together.
1) Line of sight is needed for longer connections.
2) Weather conditions like rain could interrupt the signal.
3) Other wireless equipment could cause interference.
4) Multiplied frequncies are used.
5) WiMAX is very power intensive technology and requires strong electrical support.
6) Big installation and operational cost.

WiMAX also has other disadvantages. Firstly it is very expensive. Normally it is used for corporate solution which is hard and expensive to find frequency license! So its disadvantage is the spectral limitation, in other words limitation of wireless bandwidth. For use in high density areas, it is possible that the bandwidth may not be sufficient to cater to the needs of a large number of clients, driving the costs high. It has less QoS and the speed is up to 70Mbps.

So what will be the solution for higher bandwidth (BW) requirements to the corporate sector for their intra-net? No operator wants to give all his available BW at a sector to a customer. It will not be cost effective to them. Also this is about unlicensed band. Licensed frequencies are definitely hard and expensive to buy.

If we talk about one corporate network, we'd better use 5.8Ghz or other frequency and fixed network, but not WiMAX! It has much higher throughput than WiMAX, because you can use 10Mhz for channel bandwith. It is available!

May we can go for lisence free band 2.4Ghz, 5.8Ghz. For backhaul links it is better to use WiFi, which can reach high throughput (37Mbps) in Point-to-Point links. And it has low cost and ther is no paid cannon radioelectric (use ISM band).

Regardless of what the WiMAX forum is telling us, the 2.5Ghz spectrum is only functional in urban area where it can leverage reflective surfaces and where it can have good line of site in rural markets.The basic unspoken issue here is how ineffective the 2.5Ghz systems are when addressing any type foliage, those horrible little things called leaves have a tendency to absorb all RF in that frequency, such as trees and bushes, which means that most of the East Coast. If you talk to the vendor engineers out of the reach of the marketing/sales types they will agree with the above. Wait until the FCC releases the 700Mhz spectrum and then WiAMAX makes a great deal of sense, unless the Cell Carriers win the spectrum and control it.

The last, but not lease, disadvantage of WiMAX technology is that true standards-based large mobile network deployments will probably not occur very soon. In the meantime, solutions based on EV-DO, HSDPA, and various proprietary technologies have already become available.

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