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worldwide interoperability for microwave access (WiMAX)

Worldwide Interoperability for Microwave Access (WiMAX) is a high-speed radio technology for broadband, bidirectional high-speed transmissions in the access network. This high-speed technology is suitable for stationary and mobile terminals and can supply entire city districts of a Wireless Metropolitan Area Network (WMAN). Stationary operation uses line-of-sight (LOS) links and is distinguished from mobile WiMAX, Mobile-WiMAX, by larger radio cells and higher data rates. Mobile-WiMAX, however, does not require line-of-sight for transmission.

The data rates of WiMAX are relatively high and depend on the bandwidths of the radio channel, which can be between 1.25 MHz and 20 MHz. With stationary WiMAX, a data rate of approx. 75 Mbit/s is achieved over a 20 MHz wide radio channel without MIMO (Multiple Input Multiple Output). This value results from the transmission specification of 3.75 bit/Hz for line-of-sight connections. With mobile WiMAX, this value is reduced to 2 bit/Hz, and with MIMO achieves approx. 90 Mbit/s over a 10 MHz radio channel, which is split for the downlink and the uplink.

Bandwidths and packet transmission rates for WiMAX with a line-of-sight (LOS)

Bandwidths and packet transmission rates for WiMAX with a line-of-sight (LOS)

WiMAX is an evolution of wireless LANs, based on the A version of the 802.16 Broadband Wireless Access (BWA) standard. 802.16 designates transmission frequencies between 10 GHz and 66 GHz, the A version defines frequencies between 2 GHz and 11 GHz, and the B version between 5 GHz and 6 GHz.

The

frequency bands reserved for WiMAX in Europe

frequency bands reserved for WiMAX in Europe

The WiMAX Forum intends to push ahead with standardisation for all 802.16 versions, although for the time being WiMax is designed for the frequency range between 2 GHz and 11 GHz, and specifically for the frequencies from 2.500 GHz to 2.690 GHz, 3.400 GHz to 3.600 GHz and 5.725 GHz to 5.850 GHz. In Germany, the Federal Network Agency (BNetzA) has allocated the frequency range between 3.410 GHz and 3.594 GHz to several providers. The transmission power in Germany is 3.2 W.

Modulation techniques of WiMAX

WiMAX uses Orthogonal Frequency Division Multiplex (OFDM) with 2,048 subcarriers, this, combined with Multiple Input Multiple Output (MIMO), enables the high data rates. As a standards-based technology, wireless broadband services can be provided over a WiMAX network, both for fixed connections and for portable and mobile terminals, and without line-of-sight to the base station. A key aspect is quality of service. Since WiMAX is connection-oriented, quality of service (QoS) can be agreed for specific applications. Operation with stationary antennas is based on the IEEE 802.16-2004 standard, while that for mobile WiMAX is based on 802.16e-2005. The latter technology, in conjunction withDedicated Short Range Communication (DSRC), is an interesting alternative for telematic and safety-related services in automotive technology. The further development of 802.16 towards 802.16m with data rates of 1 Gbit/s is implemented in WiMAX 2.

Characteristics of WiMax and Mobile Wi

Characteristics of WiMax and Mobile Wi

MAX WiMAX deployment scenarios include point-to-multipoint links in microwave radio, mesh networks with subscriber-to-subscriber communication, and the connection of WLANs to extend the radio cells of 802.11a up to 50 km. WiMAX could even replace WLANs and UMTS in the medium term and compete with xDSL as a broadband access technology.

In South Korea, WiBro, a broadband technology comparable to WiMAX, has been developed and is being used in Asian countries. Parts of this development are incorporated in the mobile WiMAX according to IEEE 802.16e.

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Englisch: worldwide interoperability for microwave access - WiMAX
Updated at: 22.02.2014
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