Wireless Master

Often, there have been many comparisons between WiMAX and Wi-Fi, and this results in a lot of confusion. This article will tell you about the differences.

The first difference is that WiMAX uses spectrum to deliver a point-to-point connection to the Internet. Different 802.16 standards provide different types of access, from portable (similar to the cordless phone) to fixed (an alternative to wired access, where the end user’s wireless termination point is fixed in location), and Wi-Fi uses unlimited spectrum to provide access to a network. The second difference is that Wi-Fi is more popular in end-user devices. The third difference is that WiMAX and Wi-Fi offer different qualities of service (QoS) mechanisms. For instance, WiMAX uses a mechanism which is based on connections between the base station and the user device. Here, each connection is based on specific scheduling algorithms. On the other hand, Wi-Fi has a QoS mechanism which is rather similar to fixed Ethernet, where the packets can receive different priorities based on their tags. For example, VoIP traffic may be given more priority over web browsing. The other difference is that Wi-Fi runs on the Media Access Control’s CSMA / CA protocol, which is contention-based and connectionless, and WiMAX itself runs on a connection-oriented MAC.

When talking about WiMAX, you should be aware that there is no uniform global licensed spectrum for WiMAX, however the WiMAX Forum has published three licensed spectrum profiles: 2.3 GHz, 2.5 GHz, and 3.5 GHz – this was done to make an effort in decreasing the cost, because economies of scale dictate that the more WiMAX embedded devices (like mobile phones and WiMAX-embedded laptops) are produced, the lower the unit cost. You should know that the silicon and the extra radio needed for each band are the two highest cost component of producing a mobile phone. When it comes to the Base Stations, there is a similar application of economy of scale benefits.

5.x GHz is the approved profile in the unlicensed band, and telecommunications companies usually are not likely to use this spectrum other than for backhaul, since the spectrum is not owned and controlled by them. The biggest segment available in the USA is around 2.5 GHz, and this is already assigned, primarily to Clearwire and Sprint Nextel. In other parts of the world, the Forum-approved bands will be the most likely bands used – the 2.3 GHz will probably be the most important in Asia. Countries like India and Indonesia will use a mixture of 2.5 GHz, 3.3 GHz and other frequencies. 3.5 GHz is used by Pakistan’s Wateen Telecom.

WiMAX usage may soon gain access to analog TV bands (700 MHs), but the complete roll out of digital TV is needed first, and other uses have already been suggested for that spectrum. Channel size, TDD/FDD and other necessary attributes are defined by WiMAX profiles for inter-operating products. Now, the current fixed profiles are defined for both TDD and FDD profiles. Now, all the mobile phones are TDD only.