WIMAX - WiMAX FAQ http://www.wimax.com/education/faq en-us Plone 2.0 What is non line of sight (NLOS)? Does WiMAX possess NLOS capability? http://www.wimax.com/education/faq/faq101 ctownsend Fri, 28 Nov 2008 17:07:37 -0500 WiMAX does possess NLOS capabilities, although how much and to what extent will vary depending on the spectrum bands being used.  Non line of sight indicates that the signal from a radio is received by either passing through impeding objects, such as tree tops, walls or even in some cases buildings or is received as a reflection from another building, body of water or land feature.  In both cases the broadcasting radio is completely or at least partially obscured by some obstruction. 

WiMAX radios utilize many of the best current techniques for receiving reflected signals from objects (such reflected signals are called multipath).  Some of these incorporate antenna diversity techniques.  The OFDM modulation favored by the first iteration of WiMAX actually takes advantage of reflected signals allowing radios to integrate multiple reflected signals to improve signal strength and accuracy.  The Mobile WiMAX technique of OFDMA® also advantageously integrates both in phase (or directly returned signal responses) and out of phase multipath signals (reflections of returned signals that bounce from other objects---resulting in their returning slower) to create an ultimately stronger signal. 

Additionally, for WiMAX radios that are built for service in licensed bands (currently 2.5 GHz in the US and 2.5 GHz and 3.5 GHz Internationally - although other licensed spectrums below 11 GHz will be used in other profiles in future) the additional power allowed in these bands (typically around 40 Watts) permit signal to actually penetrate through some tree cover and building walls.  There are limits posed by the physics of the spectrum range in question and power allotted.  In general NLOS ranges in the 2.5 GHz band will mostly fall between 6-8 Kilometers (4-5 Miles).  Expect additional technology to follow in coming years.  The innovation curve for WiMAX should continue to be very steep. 

In 2005 support for both Adaptive Antenna Systems sometimes called multiple input multiple output (MIMO) and beamforming antenna techniques were added to the mobile WiMAX standard.  Both technologies will be incorporated in Mobile WiMAX technology.  and significantly improves gain and thus signal strength and reliability for users.  Competing camps tout the various approaches and which is best is open to interpretation and probably the specifics of the application desired.  Navini is a company, now owned by Cisco, championing beamforming while ArrayComm's technology would be one expected to be widely used with AAS/MIMO systems.  Currently Mobile WiMAX technology is heavily invested with companies using MIMO and some type of AAS.  As the first Clearwire mobile systems come online (the company is testing its first markets now as is Sprint) they will incorporate this technology. 
 

]]> What is the actual throughput (data transfer rate) of WiMAX Technology? http://www.wimax.com/education/faq/faq38 Mike Thu, 14 Dec 2006 15:50:44 -0500 WiMAX supports very robust data throughput.  The technology at theoretical maximums could support approximately 75 Mbps per channel (in a 20 MHz channel using 64QAM ? code rate).  Real world performance will be considerably lower---perhaps maxing out around 45 Mbps/channel in some fixed broadband applications.  Remember however, that service across this channel would be shared by multiple customers.  Actual transmission capabilities on a per customer basis could vary widely depending on the carrier's chosen customer base, which is actually an inherent strength because it can be defined by QOS in a deliberate fashion to offer different bandwidth capabilities to customers with different needs (and different budgets).  Mobile WiMAX capabilities on a per customer basis will be lower in practical terms, but much better than competing 3G technologies.  WiMAX is often cited to possess a spectral efficiency of 5 bps/Hz, which is very good in comparison to other broadband wireless technologies, especially 3G.

In practical terms, Sprint has stated that it intends to deliver service at 2 Mbps to 4 Mbps to its customers with Mobile WiMAX.

The modulation scheme, whether quaternary phase shift keying (QPSK), quadrature amplitude modulation (16QAM, 64 QAM etc.) and their attendant code rate variations deliver varying bandwidth capabilities by channel size.  Like most things wireless, the devil as they say is in the details.  The good news is that pretty much all of the news is good in this regard relative to other broadband wireless and wireline competitors of WiMAX excepting LTE, which is still at least two years away from reaching the field.  The OFDMA® technology actually supports multiple modulation schemes depending upon the users range from the cell with users at closer range receiving signal across more sub-channels at, for example, 64 QAM whereas a user at greater range would receive signal across fewer sub-channels (with higher gain or power per channel) using a lower bandwidth QPSK technique for example. 

Many things affect transfer rate beyond simple radio capability---one major element being distance from the base station.  The physics of radio cannot be avoided.  Longer ranges result in lower bandwidth delivered.  Also, the spectrum channel size (1.e.  20 MHz or other) that regulation defines as appropriate for different frequency bands will dictate bandwidth capabilities at least to some extent.  Also, remember that the RF and physical environment play a strong role in throughput results.  Essentially, the real world blunts theoretical performance.

The physics of frequency range plays a powerful role in bandwidth capability.  The higher the frequency, the greater the bandwidth delivery potential and the shorter range potential.  Lower frequencies enjoy much greater range capability, but trade that off with much lower bandwidth potential.  Fortunately, even with disclaimers centered on real world impediments, WiMAX throughput is excellent.  Perhaps no litmus test is as good as the results that carriers report and several carriers have shared that they are consistently achieving as much as 5 Mbps download speeds.  Also, Clearwire has stated that it believes it can deliver upwards of 10-15 Mbps once it has access to the full Sprint panoply of spectrum in addition to its own and once it has shifted to mobile WiMAX.
 

]]> Why is WiMAX important for fixed broadband wireless? http://www.wimax.com/education/faq/faq5a Mike Thu, 14 Dec 2006 15:50:31 -0500 WiMAX is arguably even more important for the fixed broadband wireless segment than mobile broadband, at least internally to that industry. It seems clear that mobile broadband wireless holds the loftier long term monetary and customer growth potential. However, the fixed wireless segment has been fragmented essentially since its inception. There are no cohesive standards for outdoor metropolitan area networks beyond the adapted Wi-Fi technologies. Wi-Fi as a standard has been accepted in broad strokes by the industry and the public. However, it is not a well conceived citywide technology.

This industry has languished due to the inability to foment a cohesive technology strategy. Innovative features were restricted to individual brands with the result that numerous innovations if combined would have greatly improved results for all. Since most fixed broadband wireless systems in the US rely primarily upon unlicensed band technology, the potential for WiMAX to impact this segment, albeit a small segment did not appear very good. However, the advent of fixed WiMAX radio systems in the 3.65 GHz bands in the US that have been adapted from licensed band 3.5 GHz technology originally designed for European and Asian markets offers real hope for WiMAX impact in the US. Due to the number of adherents for the technology LTE will certainly play a major if not dominant part in the mobile broadband wireless equation.
 

]]> Does WiMAX use wired equivalent protocol (WEP) like Wi-Fi? http://www.wimax.com/education/faq/faq28 Mike Thu, 14 Dec 2006 15:49:42 -0500 No.  WiMAX uses much newer security protocols with enhanced encryption capabilities.  Wi-Fi itself has enjoyed several security enhancements including the WPA technology and currently WPA-2.  Both technologies have significantly improved their security technology.

]]> Can WiMAX handle Video? http://www.wimax.com/education/faq/faq30 Mike Thu, 14 Dec 2006 15:49:18 -0500 Yes.  WiMAX is designed to support high quality video as a basic aspect of the technology.  However, it should be noted that true IPTV and/or High Definition TV (HDTV0 is not widely thought to be a product that broadband wireless is completely ready for due to bandwidth limitations in delivering signal to many users simultaneously.  However, recent announced advances by some companies make claims that full High Definition TV could be achieved with approximately 2.4 Mbps of capacity, which should be well within the scope of Mobile WiMAX.  These solutions will take time to mature.  More likely limiting factors, especially for handheld devices, would include storage capacity, battery life and display technology.




]]> What is the WiMAX Security scheme/protocol? http://www.wimax.com/education/faq/faq29 Mike Thu, 14 Dec 2006 15:49:31 -0500 Realizing the sticking point that security has been in the widespread adoption of broadband wireless service, the IEEE and the Forum both determined to define a robust security environment.  WiMAX security supports two quality encryptions standards, that of the DES3 and AES, which is considered leading edge.  The standard defines a dedicated security processor on board the base station for starters.  There are also minimum encryption requirements for the traffic and for end to end authentication---the latter of which is adapted from the data-over-cable service interface specification (DOCSIS) BPI+ security protocol. 

Basically, all traffic on a WiMAX network must be encrypted using Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) which uses AES for transmission security and data integrity authentication. 

The end-to-end authentication the PKM-EAP (Extensible Authentication Protocol) methodology is used which relies on the TLS standard of public key encryption. 

At least one chip company designed processors to support this standard of onboard security processor.
 

]]> What is Korea's WiBro? http://www.wimax.com/education/faq/faq12a Mike Thu, 14 Dec 2006 15:48:17 -0500 WiBro is an acronym for "Wireless Broadband" and is actually a term that has largely been phased out in favor of the more collaborative and generic Mobile WiMAX.  Korean standards makers early on adopted the term to describe their initiatives towards adopting a version of the 802.16e standard.  Basically, the Korean standard chose to accept a specific mobile WiMAX iteration of 802.16e, rather than any future version that included backwards compatibility to fixed wireless 802.16 systems.  That approach has since proven to be the norm as mobile WiMAX is vastly favored over the fixed version.  Korea enjoys probably the most extensive 3G deployments in the world already, and its fixed broadband access per capita is the highest in the world. 

What it needed was an improved mobile broadband.  In fact, the Korean government issued the first three deployment licenses for WiBro/Mobile WiMAX in January of 2005.  And several deployments are under way.  Customer uptake has been modest so far, however, the sheer scale of broadband penetration in Korea means that customers have fewer motivations to adopt the technology.  Since the WiMAX Forum has chosen to interoperate with WiBro/Mobile WiMAX, this will ultimately result in compatible systems.  WiBro/Mobile WiMAX in many respects is driving the mobile side of WiMAX at least from the point of view of vendors eager to provide products to these early deployments. 
 

]]> Will I have WiMAX service on my Cell Phone? http://www.wimax.com/education/faq/faq5c Mike Thu, 14 Dec 2006 15:48:31 -0500 Eventually, the answer is yes.  Initially, one can expect to see Wi-Fi services converged with cellular devices.  The first GSM/WiMAX device was recently introduced into Russia.  This device operates on the carrier's WiMAX system when on its network and roams to GSM on other carrier's systems. 

This early foray will teach both the fixed and mobile wireless industries a great deal about technological co-existence.  In the US, T-Mobile began trials of a cellular/Wi-Fi fixed-mobile convergence handset in the Pacific Northwest.  A number of other firms have dual-mode phones in the marketplace, however, adoption has been slow.  T-Mobile is using a Nokia handset.  Reference designs for PC-Card form factor WiMAX cards are already in the marketplace from a number of different firms.  The short answer is that WiMAX on your phone is just around the corner.

The long term vision for broadband wireless utilizing WiMAX is clearly one of multiple technologies that fill different niches in the service delivery universe.  Clearly, mobile voice products are mature, well-realized, profitable and stable.  The truly mobile variant of mobile WiMAX will likely be the most technically difficult to achieve and may require the next version of the technology to reach really high speed access.  Of course, the equivalent fixed broadband wireless products are also enjoying innovation and already outstrip the speeds of planned mobile technology.  But as products like VoIP gain acceptance, the ability to utilize a fixed network while stationary and eventually a truly mobile broadband network (with somewhat different capabilities) will drive WiMAX/Cellular/and other technology convergences to the handheld cell phone.  In fact, this may happen much faster than previously anticipated, at least in terms of WiMAX and existing cellular technologies or LTE and existing cellular technologies.  In the long run, WiMAX and other wireless technologies offer unprecedented flexibility to consumers.

]]> Why is WiMAX important for mobile broadband wireless? http://www.wimax.com/education/faq/faq5b Mike Thu, 14 Dec 2006 15:48:44 -0500 Mobile broadband wireless or 3G has enjoyed two largely consistent standards, those being the code division multiple access (CDMA) based approach with its evolution data only (EVDO) and the universal mobile telecommunications system (UMTS) and its faster upgrade high speed downlink packet access (HSDPA), which in particular has gained some deployments in the past year.  However, these technologies were slow to mature into economically viable and affordable iterations.  The EVDO schema is now in a Revision A version which improves bandwidth considerably.  Verizon and Sprint are the first US based carriers to begin wide deployment.  Sprint currently has deployed most of its markets with 3G as has Verizon.  The bandwidth limitations have been significant and the adoption by carriers, particularly those utilizing GSM technology here in the US has been very slow (as they are essentially incompatible technologies). 

Newer broadband UMTS (universal mobile telecommunications system) systems that are GSM compatible have seen some traction with AT&T recently in the US, with the bulk of gains happening overseas, particularly in Europe.  The sheer cost factor of the technology relative to its native spectral efficiency has not been conducive to adoption either.  Estimates for the nation's cellular carriers to build a comprehensive 3G network have ranged as high as $50 Billion.  But clearly the momentum is now on the side of 3G simply due to carrier needs to improve revenue streams and also due to innovations in handsets that are driving the public hunger for broadband applications.  AT&T, for example, stated its surprise at how much higher the use of graphical and video downloads were for users of its new Apple iPhone device, which has recently been introduced in a 3G version.  Carriers are scrambling to produce higher-capacity broadband systems. 

Mobile WiMAX offers a multi-spectrum standard with a better broadband technology concept that can significantly reduce costs, improve spectral efficiency and deliver profitable services.  The growth curve of the technology, partly due to the large number of chip and radio vendor firms driving the technology, should provide a much higher innovation curve for WiMAX.  Internationally, broadband mobile wireless does enjoy greater acceptance.  Many companies are inherently more comfortable using a 3G upgrade from the GSM side due to the similarities of the technology.  The efficiency and cost savings that WiMAX are already driving as we await the final merger of Sprint and Clearwire's 2.5 GHz spectrum assets are affecting other technologies, particularly LTE, which has numerous similarities between the two technologies.

]]> What is non line of sight (NLOS)? Does WiMAX possess NLOS capability? http://www.wimax.com/education/faq/faq32 Mike Thu, 14 Dec 2006 15:48:57 -0500

WiMAX does possess NLOS capabilities, although how much and to what extent will vary depending on the spectrum bands being used. Non line of sight indicates that the signal from a radio is received by either passing through impeding objects, such as tree tops, walls or even in some cases buildings or is received as a reflection from another building, body of water or land feature. In both cases, the broadcasting radio is completely or at least partially obscured by some obstruction.

 

WiMAX radios utilize many of the best current techniques for receiving reflected signals from objects (such reflected signals are called multipath). Some of these incorporate antenna diversity techniques. The OFDM modulation favored by the first iteration of WiMAX actually takes advantage of reflected signals allowing radios to integrate multiple reflected signals to improve signal strength and accuracy. The Mobile WiMAX technique of OFDMA® also advantageously integrates both in phase (or directly returned signal responses) and out of phase multipath signals (reflections of returned signals that bounce from other objects---resulting in their returning slower) to create an ultimately stronger signal.

 

Additionally, for WiMAX radios that are built for service in licensed bands (currently 2.5 GHz in the US and 2.5 GHz and 3.5 GHz Internationally?although other licensed spectrums below 11 GHz will be used in other profiles in the future) the additional power allowed in these bands (typically around 40 Watts) permit signal to actually penetrate through some tree cover and building walls. There are limits posed by the physics of the spectrum range in question and power allotted. In general NLOS ranges in the 2.5 GHz band will mostly fall between 6-8 Kilometers (4-5 Miles). Expect additional technology to follow in the coming years. The innovation curve for WiMAX should continue to be very steep.

 

In 2005, support for both Adaptive Antenna Systems sometimes called multiple input multiple output (MIMO) and beamforming antenna techniques were added to the mobile WiMAX standard. Both technologies should significantly improve gain for and thus signal strength and reliability for users. Competing camps tout the various approaches and which is best is open to interpretation and probably the specifics of the application desired. Navini is a company championing beamforming while ArrayComm?s technology and that of Nortel are two expected to be widely used with AAS/MIMO systems.




]]> What is Europe's ETSI HiperLAN? http://www.wimax.com/education/faq/faq12b Mike Thu, 14 Dec 2006 15:47:02 -0500

The European Telecommunications Standards Institute (ETSI) formulates telecom standards very similarly to the US based IEEE. The HiperLAN standard was ETSI?s answer to the IEEE 802.11. However, HiperLAN comes in two types The Type 1 which address the 2.4 GHz band and the Type 2 which covers 5 GHz frequencies. There are other variations, some administrative relating to European licensing methodologies. For more information see RTTE Directives. However, in broad terms HiperLAN and IEEE 802.11 are roughly equivalent.




]]> What is Europe's ETSI HiperMAN? http://www.wimax.com/education/faq/faq12c Mike Thu, 14 Dec 2006 15:46:49 -0500

The ETSI HiperMAN is commonly thought to be the equivalent of IEEE 802.16 (or WiMAX). In fact, it is the European version addressing spectrum access in ranges under 11 GHz. There is a second European standard emerging called ETSI HIPERACCESS that will define (mostly licensed uses) above 11 GHz (approximately). Since the Forum has committed to supporting and incorporating the HiperMAN standards into the overall WiMAX standard, interoperability should be a constantly addressed issue. The IEEE 802.16 standard covers spectrum ranges up to about 66 GHz inclusively. Complete ETSI standards can be downloaded at: ETSI Standards.




]]> What is the WiMAX ecosystem? http://www.wimax.com/education/faq/faq41 Mike Thu, 14 Dec 2006 15:46:05 -0500 In many ways, the WiMAX ecosystem is one of the most important aspects of the power of the technology.  Much like an environmental ecosystem that inspired its name, the viability of WiMAX in general depends on the interaction of many firms delivering different, but crucial aspects of the solution to the market. 

Just like a marine ecosystem has numerous plant, fish, coral and even water conditions that affect life for all, the WiMAX ecosystem consists of standards bodies, chip vendors, radio manufacturers, systems integrators, software developers, trade groups and even the media to address various aspects of the technology. 

Just at the chip level, the variety of companies delivering solutions ranging from the OFDMA? technology being used in Mobile WiMAX to a wide variety of system-on-a-chip silicon providers, offer the variety of support and implementation strategies that will either ensure or fail to ensure that the technology supports the range of optional features that will garner customer attention.  As deployments have occurred around the world the promise of the WiMAX ecosystem to deliver lower prices is being realized.  Costs have largely dropped at all levels of the ecosystem.  And, in particular, once the Clearwire and Sprint spectrum merger is complete late in 2008 and deployments on that network accelerate, expect to see prices drop even more. 

The various radio vendors and their most direct partners, the system integrators, deliver unique solutions tailored to the various market niches that offer opportunity to them and their service provider customers.  Both fulfill specific roles within the ecosystem.

]]> What is WiMAX Mobile or 802.16e? http://www.wimax.com/education/faq/faq40 Mike Thu, 14 Dec 2006 15:46:23 -0500 Mobile WiMAX or 802.16e standard was ratified by the IEEE in late 2005 as a potential to emerge as a real viable competitor to existing 3G technologies.  This potential gained traction when South Korea elected to take a mobile WiMAX compatible standard called wireless broadband (WiBro - since renamed to Mobile WiMAX) to market.  This standard however, was based on a different formulation of OFDM than that chosen for the first product profile of 802.16-2004.  The 802.16-2004 standards support both formulations---however, the OFDM 256FFT system was chosen for 802.16-2004. 

WiBro/Mobile WiMAX uses an OFDMA? technology called 1K-FFT.  Service for the WiBro/Mobile WiMAX standard is in the 2.3 GHz spectrum range at least in Korea.  The technology can be easily adapted to other licensed spectrum.  At this point it is anticipated that the WiBro/Mobile WiMAXWiBro/Mobile WiMAX will not be used for unlicensed bands.  The Forum has already announced support for the WiBro/Mobile WiMAX standard.  For a variety of other reasons the Forum seems to favor using the scalable OFDMA approach, which allows a flexible FFT that incorporates WiBro/Mobile. 

Many members believe this approach is more spectrally efficient in general than 802.16-2004.  However, this did create a bit of a quandary in regards to Fixed WiMAX.  Since 802.16-2004 uses a different product profile the two standards products will not interoperate.  This has forced Forum members to decide whether to support both product lines, update their existing products through the 802.16-2004 path or maintain existing proprietary tech and move toward adopting Mobile WiMAX as a separate product line.  As things stand today, the Mobile WiMAX technology appears to be the clear winner amongst standards and will be used for both mobile purposes and adapted to fixed iterations as necessary.  The next version of WiMAX 802.11m will incorporate even more mobile capabilities, bandwidth capacity and technology changes to improve mobile capability.

]]> Is WiMAX a mobile technology? http://www.wimax.com/education/faq/faq39 Mike Thu, 14 Dec 2006 15:46:35 -0500 Yes.  The standard for Mobile WiMAX or IEEE 802.16e was finalized late in 2005. 

Increasingly, it appears that the 802.16e mobile WiMAX standard is the version that the majority of operators are moving towards.  While it is premature to say that the 802.16d version is likely to wither away, most vendors, even those busily shipping Fixed WiMAX radios, have upgrade procedures in place for customers to switch.

The 802.16e Mobile WiMAX standard can competently support fixed broadband applications as well as mobile.  The jury is a bit out as to how well that can be done on a homogenous mobile/fixed needs network as the types of customers served are a bit different.  In general, customers utilizing a Fixed WiMAX service are more often businesses with much higher bandwidth and IP-based service needs.  Clearly, hybrid networks may make a lot more sense in the short run for many service providers.  The most recent feedback from carriers is that they feel truly mobile capability even for most business customers has enormous marketing power and expectations are that mobility will predominate.  Clearly for US carriers, which largely means Clearwire, mobile applications are the future.

]]> What is IEEE 802.16e? http://www.wimax.com/education/faq/faq45 Mike Thu, 14 Dec 2006 15:45:02 -0500 The true Mobile WiMAX standard of 802.16e is divergent from Fixed WiMAX.  It attracted a significant number of Forum members towards an opportunity to substantively challenge existing 3G technology purveyors.  While clearly based on the same OFDM base technology adopted in 802.16-2004, the 802.16e version is designed to deliver service across many more sub-channels than the OFDM 256-FFT.  It is important to note that both standards support single carrier, OFDM 256-FFT and at least OFDMA 1K-FFT. 

The 802.16e standard adds OFDMA 2K-FFT, 512-FFT and 128-FFT capability.  Sub-channelization facilitates access at varying distance by providing operators the capability to dynamically reduce the number of channels while increasing the gain of signal to each channel in order to reach customers farther away.  The reverse is also possible.  For example, when a user gets closer to a cell site, the number of channels will increase and the modulation can also change to increase bandwidth.  At longer ranges, modulations like QPSK (which offer robust links but lower bandwidth) can give way at shorter ranges to 64 QAM (which are more sensitive links, but offer much higher bandwidth) for example.  Each subscriber is linked to a number of subchannels that obviate multi-path interference.  The upshot is that cells should be much less sensitive to overload and cell size shrinkage during the load than before.  Ideally, customers at any range should receive solid QOS without drops that 3G technology may experience.  Here is an in-depth Q&A on OFDMA®.

The 802.16e version of WiMAX also incorporates support for multiple-input-multiple-output (MIMO) antenna technology as well as Beamforming and Advanced Antenna Systems (AAS), which are all "smart" antenna technologies that significantly improve gain of WiMAX systems as well as throughput. 

The 802.16e standard is being utilized primarily in licensed spectrum for pure mobile applications.  Many firms have elected to develop the 802.16e standard exclusively for both fixed and mobile versions.  The 802.16e version of WiMAX is the closest comparable technology to the emerging LTE mobile wireless standard.  Or rather, it is more proper to say that LTE is the most comparable to Mobile WiMAX in terms of capabilities as well as technology.  The two competing technologies are really very much alike technically. 

]]> What is IEEE 802.16d? http://www.wimax.com/education/faq/faq44 Mike Thu, 14 Dec 2006 15:45:16 -0500 The current version of 802.16 Fixed WiMAX, which supersedes previous standards is the 802.16d or as it is sometimes called 802.16-2004.  Its product profile utilizes the OFDM 256-FFT (Fast Fourier Transform) system profile, which is just different enough from its sister standard of Mobile WiMAX (802.16e) that the two are incompatible.  Interestingly, both standards support both protocols within the technology protocol as well as the one chosen for Mobile WiMAX and the Korean WiBro/Mobile WiMAX standard.  If the Forum had elected to use an OFDMA version in Fixed WiMAX, it would have been far easier to provide an upgrade path. 

This particular disconnect likely points to the emerging understanding of the marketplace power of WiMAX.  More importantly, it indicates the power of the Korean WiBro/Mobile WiMAX persuasion, which heavily influenced the use of OFDMA® in the Mobile Standard. 

The Fixed WiMAX 802.16-2004 standard supports both time division duplex (TDD) and frequency division duplex (FDD) services---the latter of which is far more popular with mobile wireless providers than the newer TDD approach. 

At this point, Fixed WiMAX 802.16d systems are widely deployed in both Europe and Asia, but it is clear that for many vendors the adoption of the Mobile WiMAX 802.16e is the option of choice. 

Having said this, the opening of the US 3.65 GHz spectrum range has opened up a 802.16d opportunity in the US as vendors adapt existing 3.5 GHz systems (and mostly Fixed WiMAX based built for International use) radio systems to use in this band.

]]> What is IEEE 802.16? http://www.wimax.com/education/faq/faq43 Mike Thu, 14 Dec 2006 15:45:28 -0500 The IEEE developed the 802.16 in its first version to address line of sight (LOS) access at spectrum ranges from 10 GHz to 66 GHz.  The technology has evolved through several updates to the standard such as 802.16a, 802.16c, the Fixed WiMAX 802.16d (802.16-2004) specification and lastly the mobile 802.16e set that are currently commercially available.  The upcoming 802.16m is still a ways away from ratification.  The first update added support for 2 GHz through 11 GHz spectrum with NLOS capability.  Each update added additional functionality or expanded the reach of the standard.
 
For example, the 802.16c revision added support for spectrum ranges both licensed and unlicensed from 2 GHz to 10 GHz.  It also improved quality of service (QOS) and certain improvements in the media access control (MAC) layer along with adding support for the HiperMAN European standard.  The number of supported physical (PHY) layers was increased.  Transport mediums such as IP, Ethernet and asynchronous transfer mode (ATM) were added.

At its core, the technology is intended to take a number of best of breed proprietary enhancements that had been made by vendors using the 802.11 standard and combine them together in a very marketable and standardized WiMAX product. 

For example, older broadband wireless technology such as the Wi-Fi or 802.11b system utilized carrier sense multiple access with collision detection (CSMA/CD) crosstalk methods for base stations and customer premise equipment (CPE) to talk to one another.  Basically, this meant that each radio was constantly talking and creating inefficient overhead.  It also resulted, especially at times of high traffic, in increased packet collisions and retransmissions, further exacerbating the problem.  Some of the proprietary MAC systems built later utilized the base station to define when the CPE would be polled in order to eliminate this problem.  In the way of a permanent cure the 802.16 protocol supports multiple methods of polling that a vendor can choose to use.  Some of these include piggybacking polling requests within overhead traffic, group polling or dynamic co-opting of bandwidth from another unit by the CPE.  The key is that the radios will be interchangeable based on the Forum's initial product profile as well as more efficient.

]]> Are WiMAX standards finalized? http://www.wimax.com/education/faq/faq42 Mike Thu, 14 Dec 2006 15:45:51 -0500 Likely, WiMAX standards will never be completely finalized.  Other standards such as the cable DOCSIS (now in Version 3.0) have continued to evolve, even once a very mature level of performance was realized.  However, it has evolved more slowly.  WiMAX moved swiftly through several updates even before testing standards were defined and products began to be widely available.  The technology has evolved from the base 802.16 standard through several updates during the last few years including:
802.16a
802.16c
And finally 802.16d or 802.16-2004
All of which are primarily Fixed WiMAX standards. 

802.16e or Mobile WiMAX was finalized late in 2005.  This version is not backwards compatible with the 802.16-2004 fixed standard. 

A newer iteration of WiMAX called 802.16m that more specifically addresses numerous mobile capabilities and should considerably improve bandwidth throughput is in the works.  There is some consideration that this standard could incorporate the emerging LTE standard as well, however wireless industry politics may preclude this. 
 

]]> What is unlicensed spectrum? What frequencies are they in? http://www.wimax.com/education/faq/faq48 Mike Thu, 14 Dec 2006 15:44:14 -0500 Unlicensed or license-free spectrum as it is sometimes called simply means a spectrum band that has rules pre-defined for both the hardware and deployment methods of the radio in such a manner that interference is mitigated by the technical rules defined for the bands rather than it being restricted for use by only one entity through a spectrum licensing approach. 

Any person or entity that does not infringe upon the rules for the equipment (which in practical terms is all pre-certified by the manufacturer) or its use can put up a license free network at any time for either private or public purposes including commercial high speed internet service. 

Some of the most commonly used license free frequencies in the US are at 900 MHz, 2.4 GHz, 5.2/5.3/5.8 GHz, 24 GHz and above 60 GHz.  Other spectrum just now gaining tracton is a small band at 3.65 GHz (with specific different rules set for its use).  Much of the spectrum above 60 GHz (millimeter wave band) is unlicensed.  There is also a band at 4.9 GHz which is allocated for public safety use.  The rules vary from band to band. 

Other countries have varying rules about license free spectrum.  In the UK for example, the power allotment for 2.4 GHz is about one tenth that allowed for products sold in the US.

The rules for equipment in each band varies somewhat as does the power allotment and configuration of equipment.  One example of license free service is the many Wi-Fi Hotspots that have sprung up in cafes, airports and commercial venues in recent years.  The spectrum used for these Wi-Fi networks is mostly at 2.4 GHz and 5.2/5.3 GHz.  In the US, the 5.2/5.3 band is used for both 802.11a hotspot access as well as outdoor use.  The rules for these bands define a different power level and a more integrated antenna and radio than the 5.8 GHz band does.  Any coffee shop in America, if they follow extremely simple rules can set up an unlicensed network. 

Typically, the power allotment for each license free radio is much lower than that enjoyed by licensed spectrum holders.  One real exception to this rule is the 3.65 GHz band, which allows up to 1 Watt per MHz of power output, higher than unlicensed spectrum.  Technically the 3.65 GHz band is licensed, but the cost and rules defining the band and its use are so modest that it is effectively unlicensed spectrum.  This band is already proving to deliver NLOS capability with very solid bandwidth capability.  Power allotment largely relegates license-free providers to LOS coverage only.  Although 900 MHz products feature limited NLOS capability at short ranges from 1-2 miles depending on tree cover and building shadow.

]]> What RF Frequencies does WiMAX work in? http://www.wimax.com/education/faq/faq47 Mike Thu, 14 Dec 2006 15:44:27 -0500 The most recent versions of both WiMAX standards in 802.16 cover spectrum ranges from at least the 2 GHz range through the 66 GHz range.  This is an enormous spectrum range.  However, the practical market considerations of the Forum members dictated that the first product profiles focus on spectrum ranges that offered Forum vendors the most utility and sales potential.

The International standard of 3.5 GHz spectrum was the first to enjoy WiMAX products.  The US license free spectrum at 5.8 GHz has a few WiMAX vendors building products.  Licensed spectrum at 2.5 GHz used both domestically in the US and fairly widely abroad is the largest block in the US.  Also, in the US and in Korea products are shipping for the 2.3 GHz spectrum range.  Also in the US the 3.65 GHz band of frequencies now has WiMAX gear shipping to carriers. 

The technology appears easily extensible to lower frequencies including the valuable 700 MHz spectrum range at which the nation's largest auction (in terms of money spent) concluded in 2008.  More likely near term frequencies likely to be supported include the new 4.9 GHz public safety band (sometimes described as a Homeland security band). 

The second largest block of frequencies ever auctioned (in terms of money spent) occurred in the summer of 2006 with the AWS auction from the FCC.  This spectrum was split with the bulk being at 1.7 GHz and the rest at 2.1 GHz.  At this point, the Forum is not expected to develop a product profile for this range as most licensees have announced support for LTE systems or plan to use it for existing GSM/UMTS networks. 

The physics of radio signals typically place two primary constrictions on spectrum.  To generalize, the higher the spectrum frequency the greater the amount of bandwidth that can be transported---lower frequencies transport less bandwidth.  Secondly, the lower the frequency the greater the carry range and penetration of a signal.  For example: A 900 MHz license free radio will travel farther and penetrate some tree cover fairly easily at ranges up to one to two miles.  But it can carry much less bandwidth than a 2.4 GHz signal which cannot penetrate any tree cover whatsoever, but can deliver a lot more data.  The caveat that can somewhat alter this equation is power.  Licensed band spectrum such as 2.5 GHz by virtue of being dedicated to one user is allotted significantly higher power levels which aids in tree and building wall penetration.

]]> Do I need a License? http://www.wimax.com/education/faq/faq51 Mike Thu, 14 Dec 2006 15:43:23 -0500 Determining whether or not a service provider needs a license to deliver service is not a question answerable with a simple yes or no.  Many elements must be factored into the decision of whether or not to attempt to obtain a license. 

The first decision probably should hinge upon the business case.  Service providers must determine if the customer density in an area planned for service will support the additional cost of buying or leasing a license to begin with.  Also, are there additional physical considerations such as heavy tree cover, significant building shadow or geographic features that make license-free service much harder to deliver? If so, licensed spectrum may be the only option.

Interference is another consideration.  In metropolitan markets, unlicensed band operators, if plentiful, can create a very crowded spectrum environment, making a spectrum license much more attractive.  Ultimately, the decision as to whether a license is necessary must hinge on the economics and physical characteristics of the market in question as well as upon the availability of licensed spectrum in the desired market and lastly of course on the availability of working capital.

]]> How do I get a License? http://www.wimax.com/education/faq/faq52 Mike Thu, 14 Dec 2006 15:43:06 -0500 In the case of point to point licenses for backhaul purposes in the US, obtaining a license is relatively simple and easy.  A service provider would contact a company that acts as a frequency coordinator with the FCC.  This company is responsible to do database searches of existing PTP licenses in a given spectrum in the market to ensure there is not cross-over (to prevent interference).  The typical cost for the license and frequency coordinator services typically will run $2,500 to $4,000.  However, it should be noted that prices will vary.  Spectrum in the 900 MHz and 2.0 GHz range are rarely allotted by the FCC nowadays.  It is much more common to obtain 6 GHz, 11 GHz, 18 GHz or 23 GHz PTP licenses.  The "sweet spot" for PTP based upon cost versus capability seems to be at 18 GHz.  For firms desiring very high bandwidth and short range backhaul companies such as FiberTower Corporation or NextLink sublet frequencies in the 24 and 39 GHz band readily for modest cost.  The rules for similar types of PTP licenses used in other countries vary widely. 

Obtaining a license to deliver multi-point services in the US, especially in the 2.5 GHz range is extremely difficult---largely because there is not much spectrum available.  Most of this spectrum range is controlled by Sprint/Nextel and Clearwire (and soon primarily Clearwire)---leaving only about fifteen percent of either BRS or EBS spectrum obtainable.  The cost is not insignificant.  Typically for a firm attempting to secure spectrum for multi-point use the first step is to identify the market area desired, locate the spectrum holder (by searching the FCC site) or work with a broker who may have local contacts to help obtain control of a license. 

Expect to spend significant funds, even for rural markets.  It is not a process to attempt lightly.  For those with a compelling economic justification and need for a license, the current capabilities of WiMAX technology offer and deliver significant advantages for license holders.

]]> What is licensed Spectrum? http://www.wimax.com/education/faq/faq50 Mike Thu, 14 Dec 2006 15:43:42 -0500 All spectrum in the US and generally internationally is controlled by each country's equivalent of the FCC.  In some cases and some countries portions of the spectrum are set aside for general use such as license-free networks.  Part of the spectrum in most countries is controlled for military use, public safety and commercial services.  Only the entities so entitled may use the frequency bands they have rights to.  Considering the wide variety of International differences in other areas of public policy, radio spectrum is remarkably homogenous. 

In each country, there are portions of the spectrum set aside for commercial purposes.  Some examples of this are broadcast TV spectrum in the 700 MHz range in the US recently auctioned for broadband wireless use, or PCS cellular spectrum widely licensed across the US at 1.9 GHz.  In Europe and much of Asia, the 3.5 GHz spectrum range is used for broadband wireless, but not in the US.  This particular spectrum range could be described as the worldwide de-facto broadband wireless spectrum due to its commonality in so many countries.  In virtually all cases only the spectrum licensee can build infrastructure and offer services across its spectrum range.  This allows much higher power output without interference across the band, facilitating improved QOS.  In the US, the most readily usable licensed broadband wireless spectrum is at 2.5 GHz.  There is also licensed spectrum at 2.3 GHz and 1.9 GHz that could be used for broadband wireless commercial service delivery. 

Among the most sought after spectrum currently available in the US (and widely available internationally also) is the 2.5 GHz range.  This is very effective for the delivery of point to multi point signal to many users.  The spectrum range supports robust bandwidth capability and with licensed power allotments and WiMAX technology it supports NLOS capability and far reduced or eliminated truck roll installations.  Users can often self-install.  There are two types of 2.5 GHz licenses.  One is broadband radio service (BRS), the commercial version of the license.  These licenses can be owned by commercial companies and bought and sold basically at will.  The second is educational broadband service (EBS) which can only be owned by educational or religious type organizations with a scholastic mission.  In the US, the Catholic Church is a major holder of this spectrum.  These licenses can be leased for use by commercial entities.  In the US, Sprint/Nextel control about seventy percent of the BRS/EBS licenses .  Clearwire controls approximately another fifteen percent---with the balance held by several smaller block holders.  In fact, Clearwire and Sprint concluded a deal shifting some of Clearwire's licenses in metropolitan areas to Sprint in exchange for a larger number of rural or smaller tier city licenses prior to the two companies agreeing to merge their combined 2.5 GHz assets; a deal which should close late in 2008. 

There are special rules for a type of licensed spectrum for certain point to point links whereby multiple spectrum holders can co-exist in the same area and use licensed spectrum.  This type of PTP link is typically used for robust interference free backhaul.  It features highly focused, high gain antennas that deliver very tight beam signals.  In almost all cases, many users can be accommodated without interference.  There is spectrum in the US for this purpose at 900 MHz, 2.0 GHz, 6 GHz, 11 GHz, 18 GHz, 23 GHz and 39 GHz.  Any company that can pass the frequency coordination process (to ensure minimum or no interference) can purchase a PTP license in these bands.  It should be noted that the FCC for various reasons rarely approves PTP licenses in the 900 MHz or 2.0 GHz range.  The sweet spot for industry due to cost and capability factors seems to be the 18 GHz range, particularly when used with Ethernet radios versus packet switched technologies. 

For many years prior to the advent of fiber optic cable the nation's Telcos used 6 GHz and 11 GHz links primarily to backhaul phone service across the US.

]]> Is 3.5Ghz available in the US? http://www.wimax.com/education/faq/faq54 Mike Thu, 14 Dec 2006 15:42:30 -0500 The 3.5 GHz International standard is not available in the same bands in the US.  That spectrum range in the US is allocated for military purposes.  There are significant amounts of Fixed WiMAX product already being shipped in this range for the international market.  In fact all early WiMAX Certified products served these bands.  The FCC did open a lightly regulated band at 3.65 GHz which now has WiMAX gear available for it.  This band is offering a lot of opportunity for independent broadband wireless carriers. 

This spectrum range at 3.5 GHz is pretty much a de-facto International band.  The US really lacks commonly available licensed spectrum for broadband wireless purposes, particularly for rural applications.  Finding some additional spectrum will likely be a key challenge to the adoption of broadband wireless in the US for several years to come. 

It should be noted that the FCC has on occasion allowed what are called "Experimental Licenses" to be utilized in the 3.5 GHz range, but this is on a case by case basis.
 

]]> What frequency will WIMAX use first? http://www.wimax.com/education/faq/faq53 Mike Thu, 14 Dec 2006 15:42:46 -0500 The first frequency with interoperable certified product to ship was in the International 3.5 GHz bands.  Today products are available at 2.5 GHz, 5.8 GHz, 2.3 GHz and 3.65 GHz.  Allthough no formal product profile has been set, likely the Forum will attempt to address the 700 MHz range.  There are no plans for Mobile WiMAX at 5.8 GHz.

]]> Who owns the WiMAX Bands in the US? http://www.wimax.com/education/faq/faq55 Mike Thu, 14 Dec 2006 15:42:11 -0500 For those operators planning to deploy WiMAX systems in the unlicensed bands (currently 5.8 GHz only for WiMAX) there are no existing owners of the bands.  They may be freely deployed by anyone wishing to use the spectrum.  Providers merely need to buy equipment compliant to the FCC rules pertaining to the particular spectrum in question then deploy and operate the gear in accordance with the rules set for the specific band. 

The most usable and untapped spectrum range for multipoint service in the US is in the 2.5 GHz range.  The far majority of that spectrum is controlled by two companies Sprint/Nextel and Clearwire which are set to merge their 2.5 GHz assets in 2008, with about another fifteen percent being owned or controlled by multiple entities.  The second most commonly deployed and usable spectrum is at 2.3 GHz which is seeing some steady WiMAX deployments already.  The new AWS spectrum ranges at 1.7 GHz and 2.1 GHz will soon be major players in the US marketplace but likely not for WiMAX radios.  One potential band of great interest is at 700 MHz, which could see a WiMAX product in the near future. 

Regarding ownership, the BRS bands in 2.5 GHz are purely commercial and were originally intended for wireless cable TV.  In recent years the FCC repositioned the frequencies somewhat (redefining channel sizes for example) and began permitting mobile service in this spectrum range.  There is an additional and larger block of frequencies in the same spectrum range called EBS held mostly by school systems, universities and religious organizations.  These bands were intended to deliver educational programming and cannot be owned for commercial purposes.  They can however be leased for commercial purposes if some educational elements are also fielded.  Some major holders of such spectrum in the US are the Catholic Church, a Hispanic Telecommunications group and other institutions of higher learning.

]]> What factors will most greatly affect range for WiMAX products? http://www.wimax.com/education/faq/faq33 Mike Thu, 14 Dec 2006 15:41:33 -0500 Many factors affect range for any broadband wireless product.  Some factors include the terrain and density/height of tree cover.  Hills and valleys can block or partially reflect signals.  Bodies of water such as rivers and lakes are highly reflective of RF transmissions.  Fortunately OFDM can often turn this to an advantage---but not always.  The RF shadow of large buildings can create dead spots directly behind them, particularly if license-free spectrums are being used (with their attendant lower power allotments).  How busy the RF environment of a city or town is can greatly degrade signals---meaning that properly designed and well thought out networks are always desired.  The physics of radio transmission dictate that the greater the range between the base station and customer radio, the lower the amount of bandwidth that can be delivered, even in an extremely well-designed network.  The climate can affect radio performance---despite this there are ubiquitous wireless networks deployed today with great success in frozen Alaskan oil fields as well as lush South American and Asian climates.  And increasingly WiMAX radio antenna technology coupled with the inherent advantages of OFDM/OFDMA based radios can be a major factor in range and bandwidth capability.  The new multiple input multiple output (MIMO) and adaptive antenna systems (AAS) based antenna systems promise to maintain and even link connection and link budgets with much higher bandwidth than older technology. 

No two cities are exactly alike in terms of the challenges and opportunities presented.  In many respects, broadband wireless remains very much an art form.  However, this is also true for the cellular carriers most of us use daily.  It can be done quite well.  Mobile broadband wireless will be more difficult.  Achieving high quality of service (QOS) will be easier with fixed broadband wireless.  Despite all of these challenges, current broadband wireless is very effectively serving customers even in the most challenging environments.
 

]]> What is the Range of WiMAX? http://www.wimax.com/education/faq/faq31 Mike Thu, 14 Dec 2006 15:41:05 -0500 The answer to this question probably generates more confusion than any other single aspect of WiMAX.  In the early days of WiMAX it was common to see statements in the media describing WiMAX multipoint coverage extending 30 miles.  In a strict technical sense (in some spectrum ranges) this is correct, with even greater ranges being possible in point to point links.  In practice (and especially in the license-free bands) this is wildly overstated especially where non line of sight (NLOS) reception is concerned. 

Due to a variety of factors explained in more detail in other FAQ answers, the average cell ranges for most WiMAX networks will likely boast 4-5 mile range (in NLOS capable frequencies) even through tree cover and building walls.  Service ranges up to 10 miles (16 Kilometers) are very likely in line of sight (LOS) applications (once again depending upon frequency).  Ranges beyond 10 miles are certainly possible, but for scalability purposes may not be desirable for heavily loaded networks.  In most cases, additional cells are indicated to sustain high quality of service (QOS) capability.  For the carrier class approach, especially in regards to mobility, cells larger than this seem unlikely in the near future.  The primary WiMAX focused US carrier Clearwire has stated that its cell sites are planned at about 1.5 miles apart for mobile purposes.  This choice is clearly one intended to meet NLOS requirements.  In licensed frequencies, expect similar performance or better for WiMAX than in traditional cellular systems.

]]> Is WiMAX Technology Secure? http://www.wimax.com/education/faq/faq27 Mike Thu, 14 Dec 2006 15:39:50 -0500 The short answer is yes, as never before with broadband wireless systems.  However, this area appears to be early ground that vendors are staking out to differentiate their products and philosophies.  The WiMAX standard itself incorporates much better and more flexible security support than the Wi-Fi standard.  It can be sometimes confusing when industry pundits and detractors talk of standards such as WiMAX and then in the same breath describe ways in which vendors will be "different" or that WiMAX security might be weak.  At first glance, these comments on the part of some vendors zealous to promote the added capabilities of their products can leave one feeling uncertain about the quality and reliability of the product. 

Security is probably a good place to explain the difference between the very robust base standards of WiMAX and the ways in which individual vendors can still differentiate their products (with additional and perhaps more powerful or convenient features) beyond the features that the base standard offers.  We explain the base WiMAX security standard in a different FAQ question.  However, what is important to understand is that it is quite robust.  Perhaps more importantly, it allows for additional feature sets that could be added by various vendors to achieve security results as good as or better than any competing wireline broadband option even those being used for extremely secure governmental applications.  Typical residential service does not require the kind of security a bank, hospital or government often needs.  WiMAX can handle this. 

An example can be helpful here.  Let us say that a broadband wireless service provider chooses one particular customer premise equipment (CPE) radio that has nice features and an especially good price for its consumer based offering.  These CPEs possess normal WiMAX security functionality which is at least as good as other broadband consumer technologies such as cable.  It might choose to utilize a second vendor's base station to feed service to those radios that also possesses enhanced security capabilities adding an additional security overlay to the base security of the residential network consumer purposed CPE radios---particularly in the backhaul portion of the network.  This could add a small layer of additional support to radios that, while secure, could not feature enhanced capabilities due to the cost factors that consumer radio business requires. 

This same base unit could also offer the company an ability to support an additional layer of radios for business or governmental or health care industry customers, where health insurance privacy and portability act (HIPPA) confidentiality compliance is of great importance, that actually have a DIFFERENT CPE radio that, while more expensive, possesses feature sets that take full advantage of extended security features that are commonly added to high-security government networks.  It does not detract from the network for perfectly serviceable residential class security capable (and inexpensive) radios to coexist with premium feature (and cost) WiMAX products on the same network designed to serve specialty customers.  This approach is similar to add on products used with wireline products that often require additional hardware beyond the modem. 

In fact, as the economies of scale for WiMAX are realized through volume manufacturing, second generation, high-security products may actually be cheaper than first generation consumer grade units granting carriers enhanced service margins for high-value services.
 

]]> Does WiMAX have quality of service (QOS) capability? http://www.wimax.com/education/faq/faq26 Mike Thu, 14 Dec 2006 15:28:48 -0500 Yes.  WiMAX radios already support very robust QOS capabilities up to and incorporating asynchronous transfer mode (ATM) quality.  The MAC itself is configured to handle IP traffic, Ethernet and ATM natively.  The MAC was designed to even support future transport protocols not yet invented.  Links can be dynamically configured based on link conditions.  Basically, this dynamic configuration technique smoothens the balancing act between raw capacity and quality on the fly.  It should improve capacity or spectral efficiency a great deal.  The whole issue of QOS is becoming even more important as device capability (such as the iPhone) have revealed an apparent pent-up desire for consumers to use more rich media content such as video; a desire that was previously hidden by devices that made the experience too hard for consumers to utilize easily. 

There are a lot of elements of wireless transmission which affect the quality of signal---needs also vary depending on the type of data.  For example, VoIP can tolerate some errors, but must have low latencies (anything above 150 ms is problematic) to operate.  The packet sizes for VoIP are typically much smaller than for data.  When networks must handle blended traffic, the polling mechanism that chooses which radio can transmit with either a smaller VoIP packet or a larger data packet is crucial to ensure that data traffic is not optimized at the expense of voice.  Video transmission is similar.  Conversely, data packets do not need especially low latencies, but cannot endure transmission errors.

WiMAX partly accomplishes this by assigning variable length Protocol Data Units (PDU)s, which is basically the data packet size in the Physical Layer, that can be combined in bursts to reduce signaling overhead in the PHY layer.  This is called adaptive modulation and is a sharp contrast from the static modulation schemes of the past.  A similar technique is used for MAC signaling except they are called Service Data Units (SDU)s.  Several other techniques are used for reducing signaling transmissions and to improve the polling or communications between radios.  In the older 802.11b protocol for example, each radio and base station continues to signal and interact constantly with other radios---basically a carrier sense multiple access with collision detection (CSMA/CD) approach similar to Ethernet computer networks.  This unfortunately results in packet collision, packet loss and a great deal of inefficient cross talk in a static mode. 

WiMAX technology supports a variety of more efficient polling mechanisms that vendors and carriers can choose to use, including a defined contact cycle, grouping of radios into contact groups or even allowing customer radios to generate a brief signal indicating it needs a transmission cycle.  All of these aspects, which are intended to solve multiple problems, also result in improved QOS capabilities.  QOS is critical for delineating minimum bandwidth levels for VoIP sessions for example, as well as other leading edge IP services. 

Both common duplexing schemes are supported in WiMAX---those being FDD and TDD.  The frequency division duplexing (FDD) requires two parallel channels for send and receive.  This method is a well-understood holdover from cellular technology.  The newer time division duplexing (TDD) allows for dynamic and symmetric transmission of data across a single channel.  Where and when either should be used often depend on the frequency and the vendor's emphasis on particular strengths.  It is not unfair to suggest that TDD is more likely to be widely utilized by WiMAX product vendors.  Suffice it to say that multiple duplexing support adds significant flexibility to WiMAX---capabilities not before supported by broadband wireless technology.
 

]]> Which companies will be manufacturing WiMAX products for service providers and end-users? http://www.wimax.com/education/faq/faq22c Mike Fri, 24 Jun 2005 19:54:35 -0400

This list is extremely long and will only grow larger. A good place to start looking for firms that will produce this equipment is at the WiMAX Forum ? Members list.




]]> WiMAX equipment benefits to service providers http://www.wimax.com/education/faq/faq21 Mike Fri, 24 Jun 2005 19:54:35 -0400 The benefit of a consistent technological standard alone to the service provider community is significant.   The collection of numerous best of breed technology innovations into one consistent package have improved service.   The WiMAX spectrum efficiency gains are very solid, which are leveraging the ability to provide service to denser customer bases for lower costs.   A more consistent technological approach is a key ingredient to identifying best practices for delivering broadband wireless access consistently across multiple geographic and radio frequency (RF) environments.  

The cost savings from silicon chip based support of WiMAX technology offers profound implications.   WiMAX modems, laptop express cards and USB dongles are already available with Sprint's WiMAX launch in the US for $60-$80 USD.
 

]]> What companies are involved with WiMAX? http://www.wimax.com/education/faq/faq20 Mike Fri, 24 Jun 2005 19:54:35 -0400

As of last count, the WiMAX Forum membership included over 500 companies with many other firms evaluating the technology as a possible fit for their business and technical models.  A complete list of WiMAX Forum members can be found on its site. WiMAX Forum ? Members.




]]> How is this different from WiMAX Compliant? http://www.wimax.com/education/faq/faq16b Mike Fri, 24 Jun 2005 19:54:35 -0400 Any company could build WiMAX compliant radios from the technical specification standpoint. However, that does not mean those radios would work with other vendors gear. It is one thing to build a radio that meets a technical specification and quite another to ensure that vendor products (built with varying engineering methodologies and manufacturing processes) actually work together well in the real world. WiMAX CERTIFIED? is the only stamp of approval for such gear.




]]> What does WiMAX Forum™ Certified Mean? http://www.wimax.com/education/faq/faq16a Mike Fri, 24 Jun 2005 19:54:35 -0400

The distinction between a WiMAX compliant product and a true WiMAX CERTIFIED? radio solution is a crucial one. The WiMAX Forum is the only body empowered by its members to formulate and monitor interoperability testing. Radios that are stamped as WiMAX CERTIFIED? provide carriers and consumers peace of mind that products meet the IEEE 802.16 standard and that each vendors gear has been physically tested and certified to work with other certified radio products. This is essential to widespread adoption of the technology.







]]> How will WiMAX Forum™ Certified products benefit enterprises? Residential users? http://www.wimax.com/education/faq/faq16 Mike Fri, 24 Jun 2005 19:54:35 -0400 The existence of a cost-effective, modern leading edge alternative to the traditional wireline broadband products most commonly used in the US and International communities today will foster competition---resulting in lowered prices and enhanced services for all consumers.  Widespread adoption of WiMAX can adroitly accomplish this goal. 

Rural areas seeking economic development through the recruitment of industry gain an important tool to attract enterprise customers to more remote areas.  Internationally, countries with only modest broadband penetration could achieve rapid broadband penetration by utilizing WiMAX systems. 

WiMAX promises to help close the gap in areas where traditional broadband has not been economically viable and residents have suffered with inferior Internet connectivity.  WiMAX products offer leaps forward in technological capabilities including high data rates delivered in mobile applications, super fast network deployments, disaster support capabilities from temporary networks and much more. 

Also, much like with the Wi-Fi wireless technology, devices including laptops and PDAs will soon feature multi-mode cards that incorporate WiMAX along with Wi-Fi and/or cellular connection capabilities.  The potential convenience of achieving connectivity through multiple sources is very convenient for both corporate and residential consumers.

And finally, the advent of highly graphical smartphone handsets such as Apple's iPhone have underscored the need for bandwidth that users immediately began accessing once they had a simple interface and platform that made it easy to do so.  This new age of device functionality facilitated a previously unknown pent-up demand by consumers for more services.  And it also exposed the potential capacity problems that traditional wireless networks and even 3G networks may have in providing the rich content that users now expect.  WiMAX and WiMAX inspired competitors like LTE will offer users a much more robust solution to broadband wireless needs. 
 

]]> Intel WiMAX - Is Intel The WiMAX Forum™ http://www.wimax.com/education/faq/faq15i Mike Fri, 24 Jun 2005 19:54:35 -0400

Intel Corporation and The WiMAX Forum? are separate entities. Intel is a major supporter of WiMAX technology. Intel is a prominent member of The WiMAX Forum? along with a handful of other visionary firms. It has provided essential leadership and assistance to the Forum from its inception. Intel lends expertise, scholarship and critical support to the forum. In many ways it has also been amongst those companies most publicly supportive of WiMAX technology.




]]> Who are the leaders in WiMAX and the WiMAX Forum™? http://www.wimax.com/education/faq/faq19 Mike Fri, 24 Jun 2005 19:54:35 -0400 Every WiMAX Forum? member contributes to the development and success of the technology. The founding members of the WiMAX Forum? should be looked at as especially visionary leaders in regards to the technology. While not a founding member certainly Intel?s name has been synonymously used with WiMAX. But a number of other firms including Fujitsu, NextNet, Wi-LAN, Aperto, Redline and more recently Motorola, Samsung and others contributed significant technology, expertise and leadership to the enterprise.




]]> Are WiMAX radios available now? http://www.wimax.com/education/faq/faq18 Mike Fri, 24 Jun 2005 19:54:35 -0400  Click here for the latest certified products.



]]> Is the WiMAX Forum™ and Wi-Fi Alliance the same thing? http://www.wimax.com/education/faq/faq17 Mike Fri, 24 Jun 2005 19:54:35 -0400 The Wi-Fi Alliance and the Wi-MAX Forum are two completely separate bodies with varying charters.  However, there are similarities.  The Wi-Fi Alliance is also a non-profit standards body designed to promote the IEEE 802.11 wireless LAN technology.  Its mission includes Wi-Fi CERTIFIED? interoperability testing of Wi-Fi WLAN products. 

The WiMAX Forum has stated that it will work with other such standards bodies to ensure seamless transitions to and from each group's certified products.  The Forum's vision appears to be to encourage eventual cross-handoffs between varying broadband wireless standards to the enhancement of all parties.  Such capabilities should greatly strengthen the value proposition of all broadband wireless technology in the marketplace.  There is speculation that WiMAX and the increasingly popular LTE standard could coalesce into a single approach in future specifications of the two technologies.  However, the politics may preclude this for a time.

Another recent WiMAX alliance body is the WiMAX Global Roaming Alliance dedicated to smoother roaming experiences between broadband wireless carriers.
 

]]> What kind of companies should join the WiMAX Forum™? http://www.wimax.com/education/faq/faq15g Mike Fri, 24 Jun 2005 19:54:35 -0400 Stakeholders in the success of broadband wireless either fixed or mobile are likely members for the Forum. Current membership includes broadband service providers, equipment vendors, silicon fabricators as well as software vendors, integrators and media that cover the WiMAX space.




]]> What is the WiMAX Forum™? http://www.wimax.com/education/faq/faq15 Mike Fri, 24 Jun 2005 19:54:35 -0400

The WiMAX Forum ? was established in mid 2001 as an industry association. The Forum describes its mandate as one to coordinate testing and ensure the certification of interoperability of WiMAX equipment to the standards of the IEEE 802.16, ETSI HiperMAN and WiBro/Mobile WiMAX standards.

The WiMAX Forum shoulders the responsibility of promoting the adoption of broadband wireless gear beyond the adoption of a technical standard by working to remove barriers to broadband wireless adoption. To this end, the WiMAX Forum maintains working groups formed to address specific elements including regulatory, certification, technical, marketing, service provider, networks and applications.




]]> Why is the WiMAX Forum™ needed? http://www.wimax.com/education/faq/faq14 Mike Fri, 24 Jun 2005 19:54:35 -0400 International broadband wireless (particularly fixed wireless) technologies are fragmented and flailing to find their place in the high-speed service landscape.  The diverse, competing proprietary technologies confuse customers who are unsure how to parse the advantage claims of vendors.  It slows adoption by carriers and creates uncertainty in the customer's mind as to reliability and capability. 

Costs are high relative to competing broadband technologies.  This is a huge problem as broadband wireless access is perhaps the best choice to solve the data needs of many potential customers in rural and remote areas of the US or even developing countries lacking the basic infrastructure to support traditional wireline broadband products. 

On the Mobile side, there is great opportunity for a broadband mobile wireless standard that will deliver cheaper and higher capability broadband.  Current 3G technologies arguably are less inherently efficient and costlier to deliver per transmission bit.  In many ways, the rise of support for the LTE standard amongst mobile wireless carriers is the biggest validation for the value of what the WiMAX Forum? has accomplished.  The LTE standard has been in the planning phase for years.  However, carriers and the mobile wireless industry would have been very content to steadily build-out 3G networks and maximize their ROI returns on these networks.  It is not unfair to say that WiMAX forced the acceleration of plans to shift to LTE (which is still a couple of years away) in order to compete with the capabilities that WiMAX brings to the table.  It is worth noting too that LTE technology is quite close to WiMAX technology with differences primarily being in the techniques used for uplink and downlink. 

The WiMAX Forum's ? aim was to cure these ills by creating focus in the industry, consistent and improved technological capabilities and far lower costs for all.

]]> What are the benefits of a Global Standard? http://www.wimax.com/education/faq/faq13 Mike Fri, 24 Jun 2005 19:54:35 -0400 The best example of the benefits of a global broadband standard can be found in the early decision by European cellular carriers to adopt the global system for mobile communications (GSM).  This standard eventually caught on in many regions from Asia to the Middle East and Africa.  It is in many ways the de-facto international standard for cellular service.  This commonality of a standard resulted in very rapid adoption of cellular wireless service as well as strong innovation and progressive product offers by carriers, ranging from using one's cell phone to pay for vending machine products to short message service (SMS) products. 

In the US, the relatively fragmented technology environment with three primary competing technologies has prevented intercarrier roaming onto disparate networks.  It also resulted in higher costs for service and phone products (which have to be re-configured by vendors to work on various technologies). 

A global standard simplifies the equipment vendor process, reduces costs, speeds customer acceptance and adoption and encourages faster product and service innovation.
 

]]> What other major standards will WiMAX include/support? http://www.wimax.com/education/faq/faq12 Mike Fri, 24 Jun 2005 19:54:35 -0400 There are three International standards that are in common acceptance or in the process of finalization. These are the IEEE 802.16, the European HiperMAN and the Korean WiBro/Mobile WiMAX. These standards have many similarities, but there are some differences. A major task of the WiMAX Forum ? is to ensure that support for all three is incorporated into the global WiMAX standard.




]]> Will WiMAX be a Global Standard? http://www.wimax.com/education/faq/faq11 Mike Fri, 24 Jun 2005 19:54:35 -0400 Yes.  WiMAX is a Global Standard that has certified products shipping worldwide and interoperate with gear in the same frequency range and power range.  It is important to note that different countries utilize different spectrum frequencies for broadband delivery.  For instance, the licensed band 2.5 GHz range in the US is also widely used around the world.  However, the widely used international broadband spectrum range in the 3.5 GHz channels is not available in the US, although the FCC has recently opened a small slice of lightly regulated spectrum in the US at 3.65 GHz that uses the same WiMAX radios.  The early waves of WiMAX products are not intended to function in multiple WiMAX spectrum ranges simultaneously.  However, some of the early WiMAX radio sets may incorporate WiMAX/GSM or Wi-Fi dual connectivity from the beginning as several vendors appear to be engineering this capability into some Mobile WiMAX radios.  A dual WiMAX/GSM handset is already on the market in Russia.

]]> How is WiMAX different from IEEE 802.16? http://www.wimax.com/education/faq/faq10 Mike Fri, 24 Jun 2005 19:54:35 -0400 The WiMAX Forum? is a non profit trade association industry group with a different mission from the IEEE 802.16, ETSI HiperMAN or WiBro/Mobile WiMAX standards working groups.  The imperative of the IEEE and ETSI groups is to formulate the technology specifications.  The forum shoulders the task of incorporating the variations in the three specifications groups to ensure interoperability amongst them and to promote and market the technology and its adherents. 

Additionally, the forum regulates and defines the testing parameters for true WiMAX Certification? of interoperable products.  The ultimate result is that both bodies are very collaborative, but with clearly delineated responsibilities.

]]> WiMAX FAQ http://www.wimax.com/education/faq/index_html Mike Fri, 24 Jun 2005 19:54:35 -0400 Have a question not listed on the WiMAX FAQ? Email us at editor@wimax.com.

General WiMAX Info

WiMAX Technology & Standards

WiMAX ForumTM


WiMAX Equipment



WiMAX Regulatory


]]> What is IEEE 802.16? http://www.wimax.com/education/faq/faq09 Mike Fri, 24 Jun 2005 19:54:35 -0400 The IEEE 802.16 working group is the body tasked to determine the final specifications to be included in the WiMAX specification.  What this body does not do is ensure commercial compatibility with the standards.  The IEEE 802.16 standard is similar, but not exactly the same as the European driven HiperMAN or the Korean WiBro/Mobile WiMAX standard.  However, the IEEE 802.16 standard incorporates support for both HiperMAN and WiBro/Mobile WiMAX.  The current active 802.16 standards include both 802.16d (or 802.16-2004 - Fixed WiMAX) and 802.16e (or 802.16-2005 Mobile WiMAX).  However, the IEEE is also working on an extension of the 802.16e version called 802.16m, which will offer improved throughput and capability. 
 

]]> How do I invest into WiMAX companies? http://www.wimax.com/education/faq/faq08 Mike Fri, 24 Jun 2005 19:54:35 -0400 Vendors whose products are certified as WiMAX interoperable solutions will be companies who have proven tested interoperable radios. For a list of the members of the WiMAX Forum ? go to www.wimaxforum.org.
 
Any investment in companies deploying WiMAX certified gear should be done with the prudence taken with any other type of investment.

]]> Will WiMAX replace DSL and Cable? http://www.wimax.com/education/faq/faq07 Mike Fri, 24 Jun 2005 19:54:35 -0400 It is important to remember that WiMAX is a global broadband wireless standard.  The question of whether or not it could replace either DSL or Cable will vary from region to region.  Many developing countries simply do not have the infrastructure to support either cable or DSL broadband technologies.  In fact, many such countries are already widely using proprietary broadband wireless technologies.  Even in such regions however, it is very unlikely that either Cable or DSL technologies would disappear.  The business case and basic infrastructure often dictates that the cheapest solutions will predominate.  In many areas in developing nations, it may be cheaper to deploy Cable and DSL in the cities at least for fixed applications, whereas WiMAX will dominate outside of major towns. 

In the US, both Cable and DSL are growing extremely fast, but are not available for all customers.  Rural and remote areas often lack broadband choices if any are available at all.  When they are available, the DSL or cable plant may only exist within the town limits with no service outside the city limits.  This offers a compelling argument that low-cost WiMAX gear can leverage access to many new customers.  WiMAX also promises a whole new level of data access flexibility that will be much less location specific for customers.  This type of robust mobile, portable or fixed broadband access will be unprecedented. 

In addition, WiMAX will provide competitive options for carriers and users that will benefit traditional wireline carriers and customers by encouraging innovation and improved services.

With the advent of IPTV fiber plays are enjoying resurgence.  It does not appear that WiMAX or broadband wireless will be ready to deliver IPTV in the immediate future.  However, fixed WiMAX may offer the best potential for delivery of this potential content juggernaut.  More recently some promising new compression technologies have reached the market.  These technologies, while still new, allow the delivery of true IP-based TV signals to cellular devices.  One company asserts that it could deliver high definition TV (HDTV) in as little as 2.5 Mbps of bandwidth, with standard resolution signal requiring 1.5 Mbps.  These speeds are within the potential reach of WiMAX. 

Qualcomm and its MediaFlo system are one good example of such technologies.  It is important to note that the resolution of this TV or video system is not at the level of standard TV, but progress is occurring rapidly. 
 

]]> Will WiMAX compete with Wi-Fi? http://www.wimax.com/education/faq/faq06 Mike Fri, 24 Jun 2005 19:54:35 -0400 Clearly, WiMAX and Wi-Fi are complementary technologies and will remain so for the foreseeable future.  The widely available Wi-Fi technology used in hotspots in hotels, restaurants, airports and even larger Wi-Fi zones in some cities will continue to grow for many years.  The recent flurry of municipal Wi-Fi mesh networks has only served to cement the technology into the wireless equation.  Wi-Fi is not going away any time soon. 

As the WiMAX standard grows into its first highs scale deployment with Clearwire in 2009 and continues to gain acceptance and drive cost reductions, new chipsets that incorporate the ability to function across multiple platforms will become more common in general with the MAN portion of this network technology slowly being converted to the more robust WiMAX systems, as the business cases for hotspot venues merit.  Basically, this means that WiMAX users in a few years will be able to not only access Wi-Fi hotspots at a café, but could also have mobile citywide WiMAX access as well, along with access to other existing cellular technologies.  Multiple network capability in a single device is gaining traction and should be the norm in only a few years.  Once again, this points towards a complementary aspect to the two technologies.  True mobile access users in many cases will not require the level of bandwidth that they may need when in a fixed location.  The two technologies will fulfill differing needs for consumers. 

However, other LAN technology standards such as Bluetooth, UHF Whitespace frequencies, Ultrawideband and the 802.11n specification that offer value in shorter range hotspot networks will all grow and necessitate chipsets and laptop radios that will eventually be able to seamlessly cross these shorter range data networks as well as cellular networks and WiMAX citywide networks.  The WiMAX standard is a major part of the very bright vision of the broadband wireless future that flexibility like this promises. 

Though leaders in the industry often cite the potential for true software defined radio systems, wherein a users's handset, laptop or other devices essentially scan for the best connection for the location and spectrum available.  The industry is slowly moving in this direction, however, expect the full development of this type of seamless technology to be a few years away.  Even moderate incremental improvements in this direction could afford consumers benefits that are essentially impossible with wireline technologies.
 

]]> Why is WiMAX needed? http://www.wimax.com/education/faq/faq05 Mike Fri, 24 Jun 2005 19:54:35 -0400 To answer this question it is important to understand the state of technical fragmentation experienced in the past by the mobile wireless and fixed broadband wireless industry. Early broadband wireless systems began as extensions of indoor local area network (LAN) technology known as Wi-Fi or the 802.11b protocol. This standard has evolved into a ubiquitous and widely available standard used in short range hotspots all over the globe. However, the media access controller (MAC) and physical layer (PHY) specifications for this protocol are suboptimum for outdoor citywide wireless networks or metropolitan area networks (MAN). Recent updates and new standards such as 802.11g, 802.11a and 802.11n have improved these elements. However, once again these technologies are configured for best performance in small venues and at short range.

It should be noted that recent developments in the ratification standard of the IEEE 802.11n protocol offer the promise of significant improvements to Wi-Fi---improvements that will blur the lines of capability between WLAN and more robust WMAN (wireless metropolitan area network) systems somewhat. There are numerous 802.11n products on the shelf and being marketed vigorously, despite that fact that the standard is not yet finalized. While 802.11n is not necessarily optimized for great range, its bandwidth capabilities are a major leap ahead from Wi-Fi. Its range improvements in the hotspot will be significant also. However, despite hopes for a final standard this specification remains mired in the competing desires of various camps and their approaches to its implementation. A number of companies, including, Belkin, D-Link, Linksys and others have nevertheless launched Pre-N or pre-certified 802.11n products. These offer solid improvement over even 802.16a/g systems; however, early testing by ZDNet has shown that the gains remain modest. Also, interoperability between the various products is problematic at best. The standard appears set to be finalized near the end of 2009 which has clearly been the biggest holdup for the technology.

To compensate for deficiencies in early Wi-Fi technology, vendors developed proprietary MAC and PHY layers based on the root LAN standard of 802.11. Many of these systems are in use today and possess significant improvements in modulation scheme, polling technology and data transport that enable effective and modestly affordably citywide or rural wireless networks. However, none of these proprietary iterations of the technology are exactly the same. No two companies' products will work with each other. This means that broadband wireless carriers must use base stations and customer premise equipment from the same vendor in any given city---which may not be the best solution in some geographic and radio frequency (RF) environments.

Some of these radio vendors were even forced to manufacture their own silicon chips to deliver technical improvements. The high costs for equipment resulting from this approach significantly slowed adoption of broadband fixed wireless versus cheaper mass market technologies such as DSL and Cable modem service.

In the mobile arena, the standards for broadband wireless delivery are less fragmented. More importantly however, the cost, speeds delivered and time to market of broadband mobile solutions have been suboptimum. But that is changing.

The promise of 3G services was slow to emerge. but that is changing with wide deployments coming from Verizon using its EVDO system as well as from Sprint and AT&T Wireless, which is widely deploying its HSDPA 3G system, mobile WiMAX systems based on newer technology such as OFDMA® offer the promise of cheaper, more effective and faster deployments of broadband mobile wireless systems. More recently 3G deployments do appear to have accelerated with a number of high-profile GSM-friendly broadband technology (called UMTS or its updated version HSDPA) have gained some traction, mostly in Europe. In the US, Sprint is in the process of rolling out a CDMA network with the newer and faster Revision-A version. Perhaps most importantly, the advent of WiMAX has greatly accelerated long-held plans by cellular carriers worldwide on the Long Term Evolution (LTE) standard, which offers strong promise of a new generation of truly broadband capable wireless handsets and modems. And longer term there is potential, if not yet perhaps the technology political will, for a merging of WiMAX and LTE. LTE does appear about two years behind WiMAX systems.
 

]]> Is WiMAX Safe? http://www.wimax.com/education/faq/faq04 Mike Fri, 24 Jun 2005 19:54:35 -0400 Since much of the technology being utilized in the IEEE 802.16 standard (WiMAX standard) is widely deployed, there is a historical body of evidence supporting the safety of technologies used in upcoming WiMAX and WiMAX products.  Microwave and other spectrum technologies enjoy over a hundred years of historical evidence of safety when prudently handled and configured.  The amount of power allowed to deliver broadband wireless signal varies from frequency to frequency, however, most are modest topping out at around 40 watts at the tower relay site.  While certain basic precautions need to be taken when onsite at communications towers (i.e.  standing directly in front of active microwave links at essentially zero range) the configurations for public use are understood and safe.  Customer premise equipment is even safer. 

 



]]> Is WiMAX new? When did it start? http://www.wimax.com/education/faq/faq03 Mike Fri, 24 Jun 2005 19:54:35 -0400 WiMAX is relatively new in terms of a standards initiative - and in particular, the launch of numerous WiMAX technologies supporting chipsets by Forum members. However, much of the technology being incorporated into the IEEE 802.16 technology set is existent in the industry today and well tested. A number of best of breed broadband radio manufacturers have been offering various elements used in WiMAX for several years as proprietary technology. However, vendors rarely offered consistent iterations of radio modulation and other techniques---ensuring that solutions had to be specific to a single vendor. This is especially true on the fixed wireless side. And even more so for unlicensed band fixed wireless. However, mobile broadband wireless technologies suffered from the fragmentation of multiple proprietary approaches.

This means that much of the technological capability of WiMAX is relatively mature. In fact, the radio vendors who are members of the forum have deployed equipment in over 125 nations around the globe with trials and deployments exceeding 275. The combination of these advanced technologies into two standards packages for Fixed and Mobile broadband wireless combined with new generation optimized chipsets and tested and certified interoperability between radio manufacturers deliver a robust and powerful technology. This capability can match or exceed the performance and cost factors of other broadband technologies. This can all be achieved without traditional wireline tethers.

On the horizon, plans are to expand the WiMAX product capability as well as the early underpinnings of the next version of WiMAX, which will incorporate increasingly newer technologies. Also, the next major version of the 802.16 standard 802.16m, is already in the process of being defined. This version will offer even better throughput, spectral efficiency and capabilities along with increased interoperability.

]]> Where did the idea of WiMAX come from? http://www.wimax.com/education/faq/faq02 Mike Fri, 24 Jun 2005 19:54:35 -0400 Much of the credit for the formation of the WiMAX Forum? and to the founding members of the WiMAX Forum, which committed themselves early to the process of creating a collaborative standards body. As a founding member of the WiMAX Forum, Intel recognized that a well developed ecosystem was necessary to drive adoption and thereby drive lower hardware costs. Intel was also instrumental in getting other silicon chip manufacturers involved whose products would form the core of WiMAX technology.

]]> What is WiMAX? http://www.wimax.com/education/faq/faq01 Mike Fri, 24 Jun 2005 19:54:35 -0400 WiMAX is an IP based, wireless broadband access technology that provides performance similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of cellular networks. WiMAX is also an acronym meaning "Worldwide Interoperability for Microwave Access (WiMAX).

At its heart, however, WiMAX is a standards initiative. Its purpose is to ensure that the broadband wireless radios manufactured for customer use interoperate from vendor to vendor. The primary advantages of the WiMAX standard are to enable the adoption of advanced radio features in a uniform fashion and reduce costs for all of the radios made by companies, who are part of the WiMAX Forum? - a standards body formed to ensure interoperability via testing. The more recent Long Term Evolution (LTE) standard is a similar term describing a parallel technology to WiMAX that is being developed by vendors and carriers as a counterpoint to WiMAX.
 

]]> What is a WiMAX Forum™ Profile? http://www.wimax.com/education/faq/faq15h Mike Fri, 24 Jun 2005 19:54:35 -0400 Initially the IEEE 802.16, ETSI HiperMAN and WiBro/Mobile WiMAX standards collectively defined technologies from 2 GHz to 60 GHz.  That has since been extended to support even lower frequencies.  However, broadband wireless service is not delivered in every single spectrum range in that very wide band of frequencies.  The IEEE 802.16 for example supports multiple PHY layers as well as several different radio polling technologies that vendors could use.  Additionally, the technical rules as defined by the various controlling governmental entities throughout the US and international communities for various spectrum bands do differ, necessitating variations in the PHY layers of radios. 

Ultimately, this means that the Forum chose to define profiles that will support the PHY layers that member radio vendors will need, based on their planned equipment offerings.  Additional profiles will come online as needed.  Initially this means the Forum chose to address the 256 Fast Fourier Transform (FFT) orthogonal frequency division multiplex (OFDM) PHY with a single MAC to create an initial interoperability specification set for Fixed WiMAX.  The Mobile WiMAX standard, as ratified supports the orthogonal frequency division multiple access (OFDMA®) at 2K FFT, 1K FFT, 512 FFT or 128 FFT.  The Korean WiBro/Mobile WiMAX version uses OFDMA 1K FFT.  Frequency ranges that currently have product profiles include the licensed 2.3 GHz, 2.5 GHz, 3.5 GHz, 3.65 GHz bands and the 5.8 GHz unlicensed band.  There are plans afoot to extend WiMAX to support the newer 700 MHz spectrum range and even potentially the UHF. 

]]> How do you join the WiMAX Forum™ ? http://www.wimax.com/education/faq/faq15f Mike Fri, 24 Jun 2005 19:54:35 -0400

There are three levels of membership in The WiMAX Forum?: Regular, Principal and Board (Invitation only). Each level offers different membership benefits, responsibilities to the group and costs associated with it. Some types of companies may only join in certain categories. Details can be found at WiMAX Forum Membership Details.




]]> What does the Forum do? http://www.wimax.com/education/faq/faq15e Mike Fri, 24 Jun 2005 19:54:35 -0400 Its stated mission is to remove barriers to the adoption of broadband wireless by addressing roadblocks on several fronts from regulatory (promoting the adoption of adequate spectrum inventory to governmental regulatory bodies) to certification (ensuring the interoperability of WiMAX Forum member?s product lines) to marketing (promoting the technology and capabilities to the world).


 

]]> How many companies are in the Forum? http://www.wimax.com/education/faq/faq15d Mike Fri, 24 Jun 2005 19:54:35 -0400

Over 500. Member information can be found at WiMAX Forum ? Members.




]]> Is WiMAX or the WiMAX Forum™ a public company? http://www.wimax.com/education/faq/faq15c Mike Fri, 24 Jun 2005 19:54:35 -0400 The WiMAX Forum ? is a non-profit industry association formed by leading silicon providers, broadband wireless access carriers, radio vendors, integrators, consultants and media groups among others. It is not a commercial company in the sense of a corporation formed to sell specific products.




]]> What company owns WiMAX? http://www.wimax.com/education/faq/faq15b Mike Fri, 24 Jun 2005 19:54:35 -0400

No single company owns WiMAX. The terms WiMAX CERTIFIED? and The WiMAX Forum ? are registered trade marks of the WiMAX Forum, which is an industry association formed to promote broadband wireless adoption and certify interoperability for its member?s radio products.




]]> What is the Forum Website? http://www.wimax.com/education/faq/faq15a Mike Fri, 24 Jun 2005 19:54:35 -0400 www.wimaxforum.org



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