The IEEE 802.11 LAN MAN Standard Committee is tasked with developing standards for three types of networks: Personal Area Networks (PANs), Local Area Networks (LANs), and broadband wireless Metropolitan Area Networks (MANs).
The best-known of these is the wildly popular 802.11 Wireless Local Area Network (WLAN) specification, which has become part of our cultural lexicon, through terms like Wi-Fi and hotspot. The 802.16 standard for MANs, however, has been increasingly in the news lately as products based on it look to be available in the next year.
The 802.16 standard was initially published in 2001 and a recent enhancement (802.16a) was published in 2003. Originally dubbed the WirelessMAN standard, this term has been subsumed by the more popular WiMAX branding introduced by the WiMAX Forum, a consortium of companies that support and jointly co-market the 802.16 standards. The group also will certify 802.16-compliant products.
The purpose of 802.16 is to standardize broadband wide area wireless networking for both fixed and mobile connections, offering extremely high bandwidth connections without requiring a line-of-site communications between the device and the broadcast antenna.
To give an idea of the possibilities offered by 802.16, consider the capabilities made available by the recent 802.16a extension. 802.16a operates in the 2-11GHz frequency band over a theoretical maximum range of 31 miles with a theoretical maximum data transfer rate of 70Mbps. The following table provides a quick comparison to 802.11b:
|Data transfer rate:
|Number of users:
In actuality, WiMAX is envisioned as a complimentary technology to Wi-Fi and Bluetooth, with each designed to solve a specific problem very well.
For example, a typical deployment scenario would allow your network provider to deliver WiMAX connectivity to your corporate office, offering T1-level connection speeds and reliability. Internal to your corporate office, you may decide to deploy 802.11 hotspots for laptop and PDA users moving from office to conference room to the company lunchroom. These same laptop and PDA users may then opt to print to a local network printer via Bluetooth, allowing your enterprise to utilize wireless standards and economies of scale throughout.
While 802.16 clearly meets an industry need, its success is by no means a sure thing. It faces competition from wide area cellular 2.5G/3G technologies such as 1xEVDO (U.S. rollout by Verizon in 2004) and W-CDMA (eventual U.S. rollout announced by Cingular). In addition, the IEEE 802.20 standard, defined for wireless Wide Area Network access, could potentially compete with WiMAX since both standards could be seen as separate solutions to a similar problem (Nextel recently launched a pre-standard 802.20 trial in North Carolina using gear from Flarion Technologies).
For now, the principal advantage of the still-unratified 802.20 is that is supports mobile devices, a capability not officially supported by 802.16 until the 802.16e standard is ready (possibly in mid-2004, see below). However, because 802.16e builds on the work of 802.16a, it is likely that 802.16e devices will be widely available before 802.20-equipped devices.
While the 2003 ratification of 802.16a essentially made WiMAX ready for prime time, a host of 802.16 enhancements are planned, including:
802.16b – Quality Of Service
802.16c – Interoperability
802.16d – Builds on 802.16c
802.16e – Mobile