INTRODUCTION
Nowadays, advance of technology are move faster. The important of information technology can give a lot of goodness to our life. For example, buying and selling products by using internet technology. This case, users can survey a products or services via internet. Where, users can do a price comparison before buying. As a result, users did not to queue a long time at the supermarket or somewhere to buy a product.
To many users, the internet means worldwide network of linked computer. History of the internet has began as a research network funded by the U.S Defense Department in 1969. By 1983, the network still consisted of merely several hundred computers only a few local area networks.
More and more private companies and organization linked up to the internet, and by the mid-1990s,the internet included connection to more than sixty countries and more than two million host computers with more than fifteen million users worldwide.
By 2001, the users’ internet was representing 6.71 percent of the world population were used internet. Every year, user internet percentage always increases. For the information, the internet has many type of connection like Wireless, Cable Modem and so on. Advance type of internet connection, give something news to the users test.
Now, the wireless most used to connect the internet. IEEE 802.11 or Wi-Fi is famous wireless that used right now. However, news wireless was created. It refers to WiMAX wireless. In Malaysia, WiMAX have located in big cities only.
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DEFINITION OF WiMAX
WiMAX is short for Worldwide Interoperability for Microwave Access. WiMAX or IEEE 802.16 is a communications technology that uses radio spectrum to transmit tens of megabits per second in bandwidth between digital devices such as laptop computers. Similar to Wi-Fi, WiMAX brings with it the ability to transmit over far greater distances and to handle much more data.
WiMAX was developed by equipment manufacturers, service providers, and software companies around the world all of who were motivated to ensure that equipment, regardless of who made it, would will interoperate. In practice, WiMax will likely be made available to consumers by companies such as Cingular and Verizon. These companies have purchased the necessary rights to the radio spectrum and are building nationwide networks.
WiMAX will coexist as a radio capability on the mobile computer, along with other radio technologies such as wireless fidelity and third-generation (3G), for many years.
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HOW WiMAX WORKS
WiMAX is a connection-oriented technology. This WiMAX is affects only the Physical Layer and the MAC portion in the Data Link Layer of the OSI Model. Therefore the 802.16 specification mainly describes the scheduling of communication between towers and WiMAX devices.
The bandwidth and reach of WiMAX make it suitable for application like connecting Wi-Fi hotspots, wireless broadband support, high speed mobile data transfer and 4G.

1. WiMAX type’s connections are:-
i. Frequency Division Duplexing (FDD)
- One frequency is sent from the base tower to another station tower and from the station tower to the base tower.
- The base tower constantly communicates to all towers at one frequency and each station tower is responds back at another frequency.

ii. Time Division Duplexing (TDD).
- The base tower transmits at one frequency to a station tower and receives data from the station tower at another frequency.
- The base tower sends data at certain time intervals and allots time to wait to hear from station towers.

2. The important components needed are:
i. Base Station
These are a spot which provides you wireless connectivity, like satellites which relay signal back and forth. Together they form WiMAX network.

ii. WiMAX Hub
These are core base station from where everything is sent to base stations. This does the same what any server in network does, acts as a source or brain of the network.

iii. Access Points
These are optional somewhere but are used mainly when you have more than 3-4 wireless gadgets requiring accessing WiMAX network. Say in your home if you have 4 laptops who want to connect to internet, use access point simple.

iv. WiMAX enabled Devices
Of course this is what we use, laptops, mobiles Wi-Fi hotspots and others. They all connect to access points to get to internet.

Take a look at the image again and you will understand clearly about how WiMAX works.

Conclusion, WiMAX can be envisioned as a mesh network where each node (tower/access points) can communicate with each other in order to extend the range of WiMAX and, therefore, allows robust communication as there are multiple routes a signal can take
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WiMAX TECHNICAL SPECIFICATIONS
Have four types of WiMAX technical specifications such as:-
1. Frequency Range
- 2-11 GHz (Non Line-Of-Sight)
- 10-66 GHz (Line-Of-Sight)

2. Signal Range
- 5 miles (Non Line-Of-Sight)
- 30 miles (Line-Of-Sight)

3. Bandwidth – 70 Mbps
4. Number of users – Thousands users
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IMPLEMENTATION OF WiMAX
Implementing WiMAX is a tricky thing as it relates to sending signals in air which is open door for hackers intercepting them. But the good news is WiMAX runs on licensed bandwidth or frequency, thus is more secure.
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ADVANTAGES OF WiMAX
1. Long Range
The most significant benefit of WiMAX compared to existing wireless technologies is the range. WiMAX has a communication range of up to 30 miles. This can cover over 2800 square miles enough to blanket an entire city.

2. Low Cost
Base stations will cost under $20,000 but will still provide customers with T1-class connections.

3. Wireless
By using a WiMAX system, companies/ residents no longer have to rip up buildings or streets or lay down expensive cables.

4. High Bandwidth
WiMAX can provide shared data rates of up to 70 Mb/s. This is enough bandwidth to support more than 60 businesses at once with T1-type connectivity. It can also support over a thousand homes at 1 Mb/s DSL-level connectivity. Also, there will be a reduction in latency for all WiMAX communications.

5. WiMAX can provide users with two forms of wireless service:
i. Non Line-of-Sight:
Operates at 2 to 11 GHz, which at a lower level frequency has the ability to bend around obstacles more easily. Here, a small antenna on a computer connects to the tower and is backwards compatible with existing Wi-Fi technologies.

ii. Line-of-Sight:
Can go as high as 66 GHz since the signal is stronger and more stable, which leads to greater bandwidth. Here, a fixed dish antenna points straight at the tower or for communication between towers to tower

6. Advantages to Equipment Makers:
i. Innovate more rapidly because there exists a standards-based, stable platform upon which to rapidly add new capabilities.
ii. No longer need to develop every piece of the end-to-end solution.

7. Advantages to Operators:
i. A common platform which drives down the cost of equipment and accelerates price/performance improvements unachievable with proprietary approaches.
ii. Generate revenue by filling broadband access gaps.
iii. Quickly provision T1 / E1 level and "on demand" high margin broadband services.
iv. Reduce the dollar risk associated with deployment as equipment will be less expensive due to economies of scale.
v. No longer be locked into a single vendor since base stations will interoperate with multiple vendors' CPEs.

8. Advantages to Consumers:
i. More broadband access choices, especially in areas where there are gaps: worldwide urban centers where building access is difficult; in suburban areas where the subscriber is too far from the central office; and in rural and low population density areas where infrastructure is poor.
ii. More choices for broadband access will create competition which will result in lower monthly subscription prices.
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DISADVANTAGES OF WiMAX

1. Hesitancy
Companies are very hesitant of setting up WiMAX base stations today since it is has not reached widespread use yet. One solution to this problem is Intel making their Centrino laptop processors WiMAX enabled within the next few years. All laptops are expected to have WiMAX by 2008.

2. Exclusion of start-up companies
Even though cost provides a low barrier to entry, none of the startup companies are projected to be major players in the development of WiMAX. Intel and Cisco seem to have an obvious advantage today, and by the time it reaches widespread use, large operators will find WiMAX to be a very attractive new way of raising revenues.

3. Research and development
In order for WiMAX to succeed, new products must be researched and developed to incorporate WiMAX. Without the help of major companies investing in this R&D, WiMAX could be gravely underutilized.

4. Weather conditions like rain could interrupt the signal.

5. 0ther wireless equipment could cause interference.

6. Multiplied frequencies are used.

7. WiMAX is very power intensive technology and requires strong electrical support.

8. Big installation and operational coast.
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COMPARISON WiMAX AND Wi-Fi
WiMAX is similar to the wireless standard known as Wi-Fi, but on a much larger scale and at faster speeds. A nomadic version would keep WiMAX-enabled devices connected over large areas, much like today’s cell phones. We can compare it with Wi-Fi based on the following factors:-

1. IEEE Standards
Wi-Fi is based on IEEE 802.11 standard where as WiMAX is based on IEEE 802.16. However both are IEEE standards.

2. Range
Wi-Fi typically provides local network access for around a few hundred feet with speeds of up to 54 Mbps, a single WiMAX antenna is expected to have a range of up to 40 miles with speeds of 70 Mbps or more. As such, WiMAX can bring the underlying Internet connection needed to service local Wi-Fi networks.

3. Scalability
Wi-Fi is intended for LAN applications, users scale from one to tens with one subscriber for each CPE device. Fixed channel sizes (20MHz).
WiMAX is designed to efficiently support from one to hundreds of Consumer premises equipments (CPE) s, with unlimited subscribers behind each CPE. Flexible channel sizes from 1.5MHz to 20MHz.

4. Bit rate
Wi-Fi works at 2.7 bps/Hz and can peak up to 54 Mbps in 20 MHz channel.
WiMAX works at 5 bps/Hz and can peak up to 100 Mbps in a 20 MHz channel.

5. Quality of Service
Wi-Fi does not guarantee any QoS but WiMax will provide your several level of QoS.
As such, WiMAX can bring the underlying Internet connection needed to service local Wi-Fi networks. Wi-Fi does not provide ubiquitous broadband while WiMAX does.
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