The Worldwide Interoperability for Microwave Access (WiMAX) is an IEEE 802.16 standards-based technology. It was designed with the intent to provide last mile wireless broadband services as an alternative to cable, DSL and other wireless broadband services. It is based on wireless metropolitan access network (MAN) non-line-of-sight technology. The technology is promoted by the WiMAX Forum which was created in 2001.
Like other wireless technologies, WiMAX has evolved. An early standard was IEEE 802.16d which is called Fixed/Nomadic WiMAX. This evolved into IEEE 802.16e which is called Mobile WiMAX. The latest stage of WiMAX evolution has IEEE 802.16M which is called WiMAX Advanced or WiMAX2. WiMAX2 fully meets the International Telecommunications Union (ITU) requirements for advanced 4G technology. WiMAX2 standards require 1Gbps peak downlink access speed for fixed devices, and 100Mbps peak downlink access speeds for fast moving mobile nodes.
This technology theoretically supports cell diameters up to 30 miles but 6 mile diameters are more practical. It operates in the 2 – 10 GHz frequency ranges. It uses an orthogonal frequency division access method (OFDM), antenna multiplexing (MIMO) up to 8×8 and supports carrier channel aggregation. Channel bandwidths include 1.25 GHz, 5 GHz, 10GHz and 20 GHz. It also supports quality of service (QoS) and Advanced Encryption Standard (AES) security services. Like other mobile devices’ technologies, it supports mobile handovers and interoperates with WiFi, 3GPP UMTS/CDMA2000 systems. It supports various radio access networks (RAN) from very small cell to large cell topologies, and is fully compatible with IPv4 and IPv6.
WiMAX’s functional network reference model includes the Base Station (BS) or air-interface, Access Service Network Gateway (ASN-GW) and Connectivity Service Network (GSN).
The BS provides the air interface and related services to the mobile device. These air-interface services include: handovers, tunnel establishment, radio resource management, QoS policy enforcement, session management, and multicast group management.
The ASN-GW manages traffic aggregation and related services. These services include: location management, paging, radio resource management, and access control, encryption keys, QoS and enforcement, and communications with the CSN.
The CSN manages all of the connectivity to the Internet, other public networks, and corporate networks.
The WiMAX Forum reports that over 600 WiMAX (fixed and mobile) networks have been deployed in over 150 countries. By 2012, WiMAX networks were servicing around 1 billion subscribers worldwide. On a worldwide basis, WiMAX seems to have substantial market share although deployment in North America is limited.