Basics of WiMax (Worldwide Interoperability Microwave Access)
WiMax is a broadband wireless technology. It was developed by the WiMax Forum in the last years and It is based on the 802.16 standard which has the objective of provide high speed data transfers over the air.
Some of the possible uses of WiMax are:
- As an alternative to DSL at the “last mile”.
- As an alternative to the backhaul and access of 2G, 3G, 3’9G infrastructure.
- As an alternative option to connect rural areas to Internet where there are not any telecom infrastructure or when It is not easy to deploy it (For example in rural or disaster areas).
Technical specs of WiMax
- Frequency Range:
- 2-11 GHz (Non Line-Of-Sight)
- 10-66 GHz (Line-Of-Sight)
- Signal Range:
- 5 miles (Non Line-Of-Sight)
- 30 miles (Line-Of-Sight)
- Bandwidth: 70 Mbps.
- Physical layer: OFDM – SOFDM MIMO
- Duplex scheme: TDD (Mobile WiMax)
- Download: 144 Mbit/s (updating to 1Gbit/s in Fixed WiMax and 100Mbit/s Mobile WiMax)
- Upload: 35 Mbit/s
There are 2 main types of WiMax developments:
- Fixed WiMax: Up to 30miles – 50km of broadband wireless access (802.16d) for fixed stations in ideal conditions.
- Mobile WiMax: Up to 5 – 10 miles (15km) of broadband wireless access to mobile users (802.16e) in ideal conditions.
Between them, there are some remarkable differences apart from the fact of the fixed or mobile capabilities: Mobile WiMax has some advantages over Fixed WiMax:
- Multicast services
- The use of OFDM in the physical layer provides advantages in terms of scalability to providers.
- Mobile WiMax implements higher performing coding schemes.
- Subchannelisation allows better user scheduling.
- Lower power consumption.
- Better QoS by implementing Extended Real-Time Polling Service.