WiMAX, or Worldwide Interoperability for Microwave Access, is the certification name and market-friendly moniker for the IEEE 802.16 standard. This standard is designed to deliver non-line-of-sight wireless broadband access. The first version of the standard, 802.16d, was standardized in June 2004 and is designed to serve fixed and nomadic users. The next version, 802.16e or Mobile WiMAX, is designed to serve mobile users and is expected to be standardized in the fourth quarter of 2005.
The first revision of the 1xEV-DO standard (rev 0) is already providing fully mobile wireless broadband services to millions of users worldwide. The second revision of the 1xEV-DO standard (rev A) has been standardized and several leading wireless infrastructure and handsets vendors are gearing up to deliver products based on the standard in 2006. NxEV-DO, a future revision of 1xEV-DO that allows selectable channel bandwidths and enables higher peak rates, is currently being standardized. The following table compares the different technologies.
| IEEE 802.16d | IEEE 802.16e | EV-DO Rev 0 | EV-DO Rev A | NxEV-DO | |
|---|---|---|---|---|---|
| Standards Complete | Jul 2004 | Oct 2005 (est.) | Oct 2000 | Apr 2004 | Mar 2006 (est.) |
| Spectrum | 2 - 11 GHz (typical: 2.5 GHz, 3.5 GHz, 5.8 GHz) | < 6 GHz (typical: 2.5 GHz, 3.5 GHz) | 450 MHz, 800 MHz, 1.9 GHz, 2.1 GHz | 450 MHz, 800 MHz, 1.9 GHz, 2.1 GHz | 450 MHz, 800 MHz, 1.9 GHz, 2.1 GHz |
| Channel Bandwidth | Between 1.25 MHz and 20 MHz | Between 1.25 MHz and 10 MHz | 1.25 MHz | 1.25 MHz | Between 1.25 MHz and 20 MHz |
| Bit Rate | Up to 75 Mbps at 20 MHz | Up to 15 Mbps at 5 MHz | Up to 2.4 Mbps at 1.25 MHz | Up to 3.1 Mbps at 1.25 MHz | Up to 45 Mbps at 20 MHz |
| Mobility | Fixed and Nomadic | Mobile | Mobile | Mobile | Mobile |
| Typical Cell Radius | 3 to 5 miles (5 – 8 km) | 1 to 3 miles (2 - 5 km) | 5-15 km | 5-15 km | 5-15 km |
| Commercial Readiness | Q3’ 2005 (est.) | 2008 (est.) | June 2002 | Q4’ 2005 (est.) | 2008 (est.) |
Source: WiMAX Forum, IEEE, CDG, 3GPP2
Maturity of StandardsEV-DO was standardized in 2001 and has been commercially deployed since 2002. Commercial equipment is not yet available for the 802.16d standard, but several members of the WiMAX forum are shipping their proprietary Broadband Wireless Access (BWA) equipment as “pre-WiMAX” equipment. However, analysts note that there is little similarity between these proprietary BWA solutions and the 802.16d standard. As Michael Thelandar of Signals Research describes it: “Pre-WiMAX has as much in common with WiMAX as an Australian Shiraz has in common with a New Zealand Sauvignon Blanc”.
The next revision of WiMAX, IEEE 802.16e is expected to substantially differ from the IEEE 802.16d standard. To introduce mobility, 802.16e will introduce a new Medium Access Control (MAC) layer protocol. In addition, equipment and handsets vendors will have to support several new protocols at higher layers and backward or forward compatibility between the two technologies is not planned. In contrast, EV-DO has an evolutionary roadmap. Both 1xEV-DO Rev A and NxEV-DO will be backward compatible with 1xEV-DO Rev 0.
While mobility is a new addition to the IEEE 802.16 family of standards, it has been a mainstay of CDMA technologies. Unlike Mobile WiMAX, EV-DO has been painstakingly optimized for mobility by service providers in large commercial networks. In addition, 1xEV-DO builds upon the experience of CDMA2000 1xRTT and CDMA IS-95.
Lower network cap-ex and op-exAll wireless base stations, including 1xEV-DO and WiMAX base stations, consist of a similar set of components – digital base-band processing modules, radio transceivers and power amplifiers. Neither technology has an architectural cost advantage. Instead, the cost advantage comes from scale. Unlike WiMAX, 1xEV-DO benefits from the powerful economies of scale in CDMA2000 base station design and manufacturing. Since 1xEV-DO is fully standardized and is supported by most large infrastructure vendors, service providers can receive very competitive pricing for 1xEV-DO equipment, reducing their cap-ex. Existing CDMA2000 service providers can deploy 1xEV-DO as a simple channel card upgrade to their existing base stations and reuse their cell sites and antennas, dramatically reducing deployment costs.
Since EV-DO operates in lower frequency bands such as 450 MHz, 800 MHz and 1900 MHz, an EV-DO base station covers a significantly larger area than a WiMAX base station. An EV-DO base station operating in 450 MHz can cover 25 times more area than a WiMAX base station transmitting the same amount of power in the 2.5 GHz band. Consequently, fewer EV-DO base stations are required to cover the same area when compared with WiMAX, reducing an operator’s cap-ex and op-ex.
Lower device costWiMAX, when commercialized, is unlikely to offer lower subscriber terminal costs than EV-DO. While Mobile WiMAX is expected to leverage the economies of scale in the laptop market, EV-DO leverages the economies of scale in the mobile handset market. The mobile market is at least three times larger than the PC market and is growing at a faster pace. In 2003, 164 million PCs were shipped, of which 34 million were laptops. In the same time period, 519 million cell phones were shipped, including 117 million CDMA handsets.
1xEV-DO is already years ahead of WiMAX in terms of commercial devices. While the first fixed WiMAX base-band processor, called the Intel® PRO/Wireless 5116, was released in April 2005, the first commercial EV-DO base-band processor, the QUALCOMM MSM5500, shipped in 2001. The Intel® PRO/Wireless 5116 will not be integrated into PCs but will be used to build external WiMAX modems. In contrast, the MSM5500 (and its successor, the MSM6500) has not only been used for building modems but also high-volume phones. According to 3G Today, more than 60 different models of EV-DO end-user devices have been deployed globally. As of June 2005, 1xEV-DO had more than 16.5 million subscribers and the number is growing more than 20% every quarter.
Despite the clear advantages offered by EV-DO, a distinct niche exists for standards-compliant WiMAX technology in private enterprise networks and in rural markets using unlicensed spectrum. In well-served urban and suburban markets, service providers who own spectrum in the 2.4 GHz and 3.5 GHz bands will have to weigh the competitiveness of a WiMAX network against fixed DSL, cable or optical fiber networks and mobile 3G networks.
Airvana remains confident that EV-DO and its future revisions will continue to provide a technological and business advantage in the market for mobile broadband wireless services.