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10 Sep 11
Andy FranksOverview of wiMAX
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Internet access
WiMAX can provide at-home or mobile Internet access across whole cities or countries. In many cases this has resulted in competition in markets which typically only had access through an existing incumbent DSL (or similar) operator.
Additionally, given the relatively low costs associated with the deployment of a WiMAX network (in comparison with 3G, HSDPA, xDSL, HFC or FTTx), it is now economically viable to provide last-mile broadband Internet access in remote locations.
[edit] Backhaul
Mobile WiMAX was a replacement candidate for cellular phone technologies such as GSM and CDMA, or can be used as an overlay to increase capacity. Fixed WiMAX is also considered as a wireless backhaul technology for 2G, 3G, and 4G networks in both developed and developing nations.[7][8]
In North America, backhaul for urban operations is typically provided via one or more copper wire line connections, whereas remote cellular operations are sometimes backhauled via satellite. In other regions, urban and rural backhaul is usually provided by microwave links. (The exception to this is where the network is operated by an incumbent with ready access to the copper network.) WiMAX has more substantial backhaul bandwidth requirements than legacy cellular applications. Consequently the use of wireless microwave backhaul is on the rise in North America and existing microwave backhaul links in all regions are being upgraded.[9] Capacities of between 34 Mbit/s and 1 Gbit/s [10] are routinely being deployed with latencies in the order of 1 ms. In many cases, operators are aggregating sites using wireless technology and then presenting traffic on to fiber networks where convenient.
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WiMAX (Worldwide Interoperability for Microwave Access)
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12 Jul 11
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A critical requirement for the success of a new technology is the availability of low-cost chipsets and silicon implementations.
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27 May 09
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In North America, backhaul for urban cellular operations is typically provided via one or more copper wire line T1 connections, whereas remote cellular operations are sometimes backhauled via satellite. In most other regions, urban and rural backhaul is usually provided by microwave links. (The exception to this is where the network is operated by an incumbent with ready access to the copper network, in which case T1 lines may be used). WiMAX is a broadband platform and as such has much more substantial backhaul bandwidth requirements than legacy cellular applications. Therefore traditional copper wire line backhaul solutions are not appropriate. Consequently the use of wireless microwave backhaul is on the rise in North America and existing microwave backhaul links in all regions are being upgraded. [20] Capacities of between 34 Mbit/s and 1 Gbit/s are routinely being deployed with latencies in the order of 1ms.[citation needed] In many cases, operators are aggregating sites using wireless technology and then presenting traffic on to fiber networks where convenient.
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n contrast, the 802.16 MAC uses a scheduling algorithm
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the 802.16 scheduling algorithm can also be more bandwidth efficient
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allows the base station to control QoS parameters
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802.16e-2005 in 2005 and uses scalable orthogonal frequency-division multiple access (SOFDMA)
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as opposed to the orthogonal frequency-division multiplexing (OFDM) version with 256 sub-carriers (of which 200 are used) in 802.16d
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802.16e also adds a capability for full mobility support
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when some of those conditions are bad, then the system chooses a more robust physical mode (burst profile) which means less bits per OFDM/SOFDMA symbol
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accurate decoding is easier
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the signal could (harmfully) reach farther distances than expected due to tunnel effects (constructive interference with neighbor frequencies)
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Wi-Fi has 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.
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Each connection is based on specific scheduling algorithms.
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Analog TV bands (700 MHz) may become available for WiMAX usage
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Both of these companies have stated their intention of supporting LTE, a technology which competes directly with WiMAX
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WiMAX is spectral efficiency
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The notable advantage of WiMAX comes from combining SOFDMA with smart antenna technologies
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The direct use of frequency domain organization simplifies designs using MIMO-AAS compared to CDMA/WCDMA methods, resulting in more effective systems
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WiMAX can either operate at higher bitrates or over longer distances but not both
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Mobile WiMAX devices typically have omnidirectional antennae which are of lower-gain compared to directional antennas but are more portable.
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the general consensus is that WiMAX requires various granular and distributed network architectures to be incorporated within the IEEE 802.16 task groups. This includes wireless mesh, grids, network remote station repeaters which can extend networks and connect to backhaul.
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IEEE Std 802.16-2004 addresses only fixed systems
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Adding support for mobility
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and is the very basis of 'Mobile WiMAX'
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09 Jan 09
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05 Sep 08
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01 May 08
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enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL
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WiMAX is a long-range system, covering many kilometers that typically uses licensed spectrum (although it is also possible to use unlicensed spectrum) to deliver a point-to-point connection to the Internet from an ISP to an end user.
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Wi-Fi is a shorter range system, typically hundreds of meters, that uses unlicensed spectrum to provide access to a network, typically covering only the network operator's own property. Typically Wi-Fi is used by an end user to access their own network, which may or may not be connected to the Internet. If WiMAX provides services analogous to a cellphone, Wi-Fi is more analogous to a cordless phone.
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04 Dec 07
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30 Jan 07
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24 Jul 06
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21 Mar 05
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