WiMAX - The Future of Everything

WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes. In WiMax technology, differnet modes like point-to-multipoint links to portable and fully mobile internet access are used. The technology provides up to 72 Mbit/s symmetric broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access or Fixes WiMax). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum defined WiMAX as - a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL. The WiMAX Forum now claims there are over 400 WiMAX networks deployed in over 130 countries.

Companies are closely examining WiMAX for last mile connectivity. The resulting competition may bring lower pricing for both home and business customers or bring broadband access to places where it has been economically unavailable.

The bandwidth and range of WiMAX make it suitable for the following potential applications:

• Connecting Wi-Fi hotspots to the Internet.
• Providing a wireless alternative to cable and DSL for "last mile" broadband access.
• Providing data and telecommunications services.
• Providing a source of Internet connectivity as part of a business continuity plan. That is, if a business has a fixed and a wireless Internet connection, especially from unrelated providers, they are unlikely to be affected by the same service outage.
• Providing portable connectivity.

WiMAX access was used to assist with communications in Aceh, Indonesia, after the tsunami in December 2004. All communication infrastructure in the area, other than amateur radio, was destroyed, making the survivors unable to communicate with people outside the disaster area and vice versa. WiMAX provided broadband access that helped regenerate communication to and from Aceh. In addition, WiMAX was used by Intel Corporation to assist the FCC and FEMA in their communications efforts in the areas affected by Hurricane Katrina.

WiMAX subscriber units are available in both indoor and outdoor versions from several manufacturers. Self-install indoor units are convenient, but radio losses mean that the subscriber must be significantly closer to the WiMAX base station than with professionally-installed external units. As such, indoor-installed units require a much higher infrastructure investment as well as operational cost (site lease, backhaul, maintenance) due to the high number of base stations required to cover a given area. Indoor units are comparable in size to a cable modem or DSL modem. Outdoor units are roughly the size of a laptop PC, and their installation is comparable to a residential satellite dish.

With the potential of mobile WiMAX, there is an increasing focus on portable units. This includes handsets (similar to cellular smartphones) and PC peripherals (PC Cards or USB dongles). In addition, there is much emphasis from operators on consumer electronics devices (game terminals, MP3 players and the like); it is notable this is more similar to Wi-Fi than 3G cellular technologies.

Current certified devices can be found at the WiMAX Forum web site. This is not a complete list of devices available as certified modules are embedded into laptops, MIDs (Mobile Internet Devices), and private labeled devices.

WiMAX is a possible replacement candidate for cellular phone technologies such as GSM and CDMA, or can be used as a layover to increase capacity. It has also been considered as a wireless backhaul technology for 2G, 3G, and 4G networks in both developed and poor nations.

Comparisons and confusion between WiMAX and Wi-Fi are frequent, possibly because both begin with the same two letters, are based upon IEEE standards beginning with "802.", and are related to wireless connectivity and Internet access. However, the two standards are aimed at different applications.

• WiMAX uses licensed spectrum to deliver a point-to-point connection to the Internet from an ISP to an end user. Different 802.16 standards provide different types of access, from portable (similar to a cordless phone) to fixed (an alternative to wired access, where the end user's wireless termination point is fixed in location.) WiMax is developed primarily for wireless metropolitan area networks (WMANs), with a transmission range of a few kilometers.
• Wi-Fi uses unlicensed spectrum to provide access to a network. Wi-Fi has primarily been developed for wireless local area networks (WLANs), with a transmission range of up to 100m. Wi-Fi therefore is often used for last-mile delivery, such as hotspots.
• WiMAX and Wi-Fi have quite different Quality of Service (QoS) mechanisms. WiMAX uses a mechanism based on connections between the Base Station and the user device. Each connection is based on specific scheduling algorithms. Wi-Fi has introduced a QoS mechanism similar to fixed Ethernet, where packets can receive different priorities based on their tags. For example VoIP traffic may be given priority over web browsing.
• Wi-Fi runs on the MAC's CSMA/CA protocol, which is connectionless and contention based, whereas WiMAX runs a connection-oriented MAC.

A commonly-held misconception is that WiMAX will deliver 70 Mbit/s over 31 miles/50 kilometers. In reality, WiMAX can only do one or the other — operating over maximum range (31 miles/50 km) increases bit error rate and thus must use a lower bitrate. Lowering the range allows a device to operate at higher bitrates.

Typically, fixed WiMAX networks have a higher-gain directional antenna installed near the client (customer) which results in greatly increased range and throughput. Mobile WiMAX networks are usually made of indoor "customer premises equipment" (CPE) such as desktop modems, laptops with integrated Mobile WiMAX or other Mobile WiMAX devices. Mobile WiMAX devices typically have an omni-directional antenna which is of lower-gain compared to directional antennas but are more portable. In practice, this means that in a line-of-sight environment with a portable Mobile WiMAX CPE, speeds of 10 Mbit/s at 6 miles/10 km could be delivered. However, in urban environments they may not have line-of-sight and therefore users may only receive 10 Mbit/s over 2 km. In current deployments, throughputs are often closer to 2 Mbit/s symmetric at 10 km with fixed WiMAX and a high gain antenna. It is also important to consider that a throughput of 2 Mbit/s can mean 2 Mbit/s, symmetric simultaneously, 1 Mbit/s symmetric or some asymmetric mix (e.g. 0.5 Mbit/s downlink and 1.5 Mbit/s uplink or 1.5 Mbit/s downlink and 0.5 Mbit/s uplink), each of which required slightly different network equipment and configurations. Higher-gain directional antennas can be used with a Mobile WiMAX network with range and throughput benefits but the obvious loss of practical mobility.

Like most wireless systems, available bandwidth is shared between users in a given radio sector, so performance could deteriorate in the case of many active users in a single sector. In practice, many users will have a range of 2-, 4-, 6-, 8-, 10- or 12 Mbit/s services and additional radio cards will be added to the base station to increase the capacity as required.

Because of this, various granular and distributed network architectures are being incorporated into WiMAX through independent development and within the IEEE 802.16j mobile multi-hop relay (MMR) task group. This includes wireless mesh, grids, network remote station repeaters which can extend networks and connect to backhaul.