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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. 
 

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.
 

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.
 

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.

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.
 

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.

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.

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.

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.

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.