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124-454: The WiMAX Forum was formed in June 2001 to promote conformity and interoperability, including the definition of system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL ". IEEE 802.16m or WirelessMAN-Advanced was a candidate for 4G , in competition with

248-428: A scheduling algorithm for which the subscriber station needs to compete only once for initial entry into the network. After network entry is allowed, the subscriber station is allocated an access slot by the base station. The time slot can enlarge and contract, but remains assigned to the subscriber station, which means that other subscribers cannot use it. In addition to being stable under overload and over-subscription,

372-419: A beam of radio waves in the microwave frequency range to transmit video , audio , or data between two locations, which can be from just a few feet or meters to several miles or kilometers apart. Microwave links are commonly used by television broadcasters to transmit programmes across a country, for instance, or from an outside broadcast back to a studio. Mobile units can be camera mounted, allowing cameras

496-766: A century since the original laying of copper phone cables. In recent years, usage of the term "last mile" has expanded outside the communications industries, to include other distribution networks that deliver goods to customers, such as the pipes that deliver water and natural gas to customer premises, and the final legs of mail and package delivery services. The term has also been used to describe education and training providers that more tightly link individuals with job opportunities. The increasing worldwide demand for rapid, low- latency and high-volume communication of information to homes and businesses has made economical information distribution and delivery increasingly important. As demand has escalated, particularly fueled by

620-435: A channel can therefore be viewed in terms of sending sufficient Information-Carrying Energy (ICE). For this reason the concept of an ICE 'pipe' or 'conduit' is relevant and useful for examining existing systems. The distribution of information to a great number of widely separated end-users can be compared to the distribution of many other resources. Some familiar analogies are: All of these have in common conduits that carry

744-479: A conduit less expensive as the capacity is increased. There is an overhead associated with the creation of any conduit. This overhead is not repeated as capacity is increased within the potential of the technology being utilized. As the Internet has grown in size, by some estimates doubling in the number of users every eighteen months, economy of scale has resulted in increasingly large information conduits providing

868-535: A connection between New York City and Murray Hill, the location of Bell Laboratories in 1946. The TDX system was set up between New York and Boston in 1947. The TDX was upgraded to the TD2 system, which used [the Morton tube, 416B and later 416C, manufactured by Western Electric] in the transmitters, and then later to TD3 that used solid-state electronics . Remarkable were the microwave relay links to West Berlin during

992-419: A diameter of up to 4 m (13 ft). Highly directive antennas permit an economical use of the available frequency spectrum, despite long transmission distances. Because of the high frequencies used, a line-of-sight path between the stations is required. Additionally, in order to avoid attenuation of the beam, an area around the beam called the first Fresnel zone must be free from obstacles. Obstacles in

1116-413: A distance of 56 km (35 miles), was followed in 1935 by a 300 MHz telecommunication link, the first commercial microwave relay system. The development of radar during World War II provided much of the microwave technology which made practical microwave communication links possible, particularly the klystron oscillator and techniques of designing parabolic antennas. Though not commonly known,

1240-500: A faster, more reliable connection. Some companies believe that ADSL aggregation (or "bonding") is the solution to the UK's last mile problem. Microwave radio Microwave transmission is the transmission of information by electromagnetic waves with wavelengths in the microwave frequency range of 300 MHz to 300 GHz (1 m - 1 mm wavelength) of the electromagnetic spectrum . Microwave signals are normally limited to

1364-488: A few kilometers, not enough for long-distance communication. The electronic technologies needed in the millimeter wave band are also in an earlier state of development than those of the microwave band. More recently, microwaves have been used for wireless power transmission . Microwave radio relay is a technology widely used in the 1950s and 1960s for transmitting information, such as long-distance telephone calls and television programs between two terrestrial points on

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1488-435: A free space environment, beyond a given length, the losses in a wireless system are lower than those in a wired system. In practice, the presence of atmosphere, and especially obstructions caused by terrain, buildings and foliage can greatly increase the loss above the free space value. Reflection, refraction and diffraction of waves can also alter their transmission characteristics and require specialized systems to accommodate

1612-492: A half duplex FDD, that allows for a low cost implementation. Devices that provide connectivity to a WiMAX network are known as subscriber stations (SS). Portable units include handsets (similar to cellular smartphones ); PC peripherals (PC Cards or USB dongles); and embedded devices in laptops, which are now available for Wi-Fi services. In addition, there is much emphasis by operators on consumer electronics devices such as Gaming consoles, MP3 players and similar devices. WiMAX

1736-530: A line of sight limits the separation between stations to the visual horizon, about 30 to 50 miles (48 to 80 km). For longer distances, the receiving station could function as a relay, retransmitting the received information to another station along its journey. Chains of microwave relay stations were used to transmit telecommunication signals over transcontinental distances. Microwave relay stations were often located on tall buildings and mountaintops, with their antennas on towers to get maximum range. Beginning in

1860-587: A lower cost per bit. During the Cold War, the US intelligence agencies, such as the National Security Agency (NSA), were reportedly able to intercept Soviet microwave traffic using satellites such as Rhyolite/Aquacade . Much of the beam of a microwave link passes the receiving antenna and radiates toward the horizon, into space. By positioning a geosynchronous satellite in the path of the beam,

1984-474: A maximum distance. The decrease in information capacity made available to an individual user is roughly proportional to the number of users sharing a LAN. In the late 20th century, improvements in the use of existing copper telephone lines increased their capabilities if maximum line length is controlled. With support for higher transmission bandwidth and improved modulation, these digital subscriber line schemes have increased capability 20-50 times as compared to

2108-575: A mix of 2.5 GHz, 3.3 GHz and other frequencies. Pakistan 's Wateen Telecom uses 3.5 GHz. Analog TV bands (700 MHz) may become available, but await the complete digital television transition , and other uses have been suggested for that spectrum. In the USA the FCC auction for this spectrum began in January 2008 and, as a result, the biggest share of the spectrum went to Verizon Wireless and

2232-406: A more robust mode (burst profile) which means fewer bits per OFDM/SOFDMA symbol; with the advantage that power per bit is higher and therefore simpler accurate signal processing can be performed. Burst profiles are used inverse (algorithmically dynamic) to low signal attenuation; meaning throughput between clients and the base station is determined largely by distance. Maximum distance is achieved by

2356-536: A much lower bitrate. Conversely, reducing the range (to under 1 km) allows a device to operate at higher bitrates. A citywide deployment of WiMAX in Perth , Australia demonstrated that customers at the cell-edge with an indoor Customer-premises equipment (CPE) typically obtain speeds of around 1–4 Mbit/s, with users closer to the cell site obtaining speeds of up to 30 Mbit/s. Last mile (telecommunications) The last mile , or last kilometer , in

2480-690: A multitude of sharing users and each user must have large antenna, with attendant directivity and pointing requirements, in order to obtain even modest information-rate transfer. These requirements render high-information-capacity, bi-directional information systems uneconomical. This is one reason why the Iridium satellite system was not more successful. For terrestrial and satellite systems, economical, high-capacity, last-mile communications requires point-to-point transmission systems. Except for extremely small geographic areas, broadcast systems are only able to deliver high S/N ratios at low frequencies where there

2604-487: A narrow beam of microwaves. In microwave radio relay, a microwave transmitter and directional antenna transmits a narrow beam of microwaves carrying many channels of information on a line of sight path to another relay station where it is received by a directional antenna and receiver, forming a fixed radio connection between the two points. The link was often bidirectional, using a transmitter and receiver at each end to transmit data in both directions. The requirement of

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2728-639: A number of applications including broadband connections, cellular backhaul , hotspots , etc. It is similar to Long-range Wi-Fi , but it can enable usage at much greater distances. The scalable physical layer architecture that allows for data rate to scale easily with available channel bandwidth and range of WiMAX make it suitable for the following potential applications: WiMAX can provide at-home or mobile Internet access across whole cities or countries. In many cases, this has resulted in competition in markets which typically only had access through an existing incumbent DSL (or similar) operator. Additionally, given

2852-400: A relatively small amount of a resource a short distance to a very large number of physically separated endpoints. Also common are conduits supporting more voluminous flow, which combine and carry many individual portions over much greater distances. The shorter, lower-volume conduits, which individually serve only one or a small fraction of the endpoints, may have far greater combined length than

2976-409: A relatively small number of local users require a prohibitively large number of broadcast locations or points of presence along with a large amount of excess capacity to make up for the wasted energy. Recently a new type of information transport midway between wired and wireless systems has been discovered. Called E-Line , it uses a single central conductor but no outer conductor or shield. The energy

3100-475: A site visit (truck roll) from the central office via a web interface. In many countries the last mile link which connects landline business telephone customers to the local telephone exchange is often an ISDN30 which can carry 30 simultaneous telephone calls. Community antenna television systems, also known as cable television , have been expanded to provide bidirectional communication over existing physical cables. However, they are by nature shared systems and

3224-421: A springboard past its competitors. The cable companies were expected to provide media services to other partners while gaining access to the wireless network as a Mobile virtual network operator to provide triple-play services. Some wireless industry analysts, such as Ken Dulaney and Todd Kort at Gartner, were skeptical how the deal would work out: Although fixed-mobile convergence had been a recognized factor in

3348-411: A whole, to be the most expensive and difficult part of the complete distribution system. These characteristics have been displayed in the birth, growth, and funding of the Internet. The earliest inter-computer communication tended to be accomplished with direct wireline connections between individual computers. These grew into clusters of small local area networks (LAN). The TCP/IP suite of protocols

3472-548: A wireless system is used to reach the customer. In contrast to wired delivery systems, wireless systems use unguided waves to transmit ICE. They all tend to be unshielded and have a greater degree of susceptibility to unwanted signal and noise sources. Because these waves are not guided but diverge, in free space these systems are attenuated following an inverse-square law , inversely proportional to distance squared. Losses thus increase more slowly with increasing length than for wired systems, whose loss increases exponentially . In

3596-419: Is a future-proof technology that meets the needs of today's users, but unlike other copper-based and wireless last-mile mediums, also has the capacity for years to come, by upgrading the end-point optics and electronics without changing the fiber infrastructure. The fiber itself is installed on existing pole or conduit infrastructure and most of the cost is in labor, providing good regional economic stimulus in

3720-433: Is also considered as a wireless backhaul technology for 2G , 3G , and 4G networks in both developed and developing nations. In North America, backhaul for urban operations is typically provided via one or more copper wire line connections, whereas remote cellular operations are sometimes backhauled via satellite. In other regions, urban and rural backhaul is usually provided by microwave links . (The exception to this

3844-406: Is done automatically then the practical deployment should avoid high interference and multipath environments. The reason for which is obviously that too much interference causes the network to function poorly and can also misrepresent the capability of the network. The system is complex to deploy as it is necessary to track not only the signal strength and CINR (as in systems like GSM ) but also how

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3968-503: Is important to further examine what makes information conduits effective. As the Shannon–Hartley theorem shows, it is the combination of bandwidth and signal-to-noise ratio which determines the maximum information rate of a channel. The product of the average information rate and time yields total information transfer. In the presence of noise , this corresponds to some amount of transferred information-carrying energy (ICE). Therefore,

4092-408: Is increased, is an artifact of the change in the aperture of a given type of antenna. Relative to the last-mile problem, these longer wavelengths have an advantage over light waves when omnidirectional or sectored transmissions are considered. The larger aperture of radio antennas results in much greater signal levels for a given path length and therefore higher information capacity. On the other hand,

4216-606: Is more similar to Wi-Fi than to other 3G cellular technologies. The WiMAX Forum website provides a list of certified devices. However, this is not a complete list of devices available as certified modules are embedded into laptops, MIDs ( Mobile Internet devices ), and other private labeled devices. WiMAX gateway devices are available as both indoor and outdoor versions from manufacturers including Vecima Networks , Alvarion , Airspan , ZyXEL , Huawei , and Motorola . The list of WiMAX networks and WiMAX Forum provide more links to specific vendors, products and installations. Many of

4340-493: Is not sufficient spectrum to support the large information capacity needed by a large number of users. Although complete "flooding" of a region can be accomplished, such systems have the fundamental characteristic that most of the radiated ICE never reaches a user and is wasted. As information requirements increase, broadcast wireless mesh systems (also sometimes referred to as microcells or nano-cells) which are small enough to provide adequate information distribution to and from

4464-606: Is particularly prevalent in providing rural broadband service over copper. New technologies such as G.Fast and VDSL2 offer viable high speed solutions to rural broadband provision over existing copper. In light of this many companies have developed automated cross connects (cabinet based automated distribution frames) to eliminate the uncertainty and cost associated with maintaining broadband services over existing copper, these systems usually incorporate some form of automated switching and some include test functionality allowing an ISP representative to complete operations previously requiring

4588-468: Is referred to as free-space optical communication . Being short, light waves can be focused or collimated with a small lens/antenna, and to a much higher degree than radio waves. Thus, a receiving device can recover a greater portion of the transmitted signal. Also, because of the high frequency, a high data transfer rate may be available. However, in practical last mile environments, obstructions and de-steering of these beams, and absorption by elements of

4712-408: Is regulated by International Telecommunication Union ( ITU-R ) and local regulations ( ETSI , FCC ). In the last decade the dedicated spectrum for each microwave band has become extremely crowded, motivating the use of techniques to increase transmission capacity such as frequency reuse, polarization-division multiplexing , XPIC , MIMO . The history of radio relay communication began in 1898 with

4836-449: Is to move to the later standard (e.g., Fixed WiMAX to Mobile WiMAX). The original version of the standard on which WiMAX is based ( IEEE 802.16 ) specified a physical layer operating in the 10 to 66 GHz range. 802.16a, updated in 2004 to 802.16-2004, added specifications for the 2 to 11 GHz range. 802.16-2004 was updated by 802.16e-2005 in 2005 and uses scalable orthogonal frequency-division multiple access (SOFDMA), as opposed to

4960-412: Is transported in a plane wave which, unlike radio does not diverge, whereas like radio it has no outer guiding structure. This system exhibits a combination of the attributes of wired and wireless systems and can support high information capacity utilizing existing power lines over a broad range of frequencies from RF through microwave . Aggregation is a method of bonding multiple lines to achieve

5084-507: Is where the network is operated by an incumbent with ready access to the copper network.) WiMAX has more substantial backhaul bandwidth requirements than legacy cellular applications. Consequently, the use of wireless microwave backhaul is on the rise in North America and existing microwave backhaul links in all regions are being upgraded. Capacities of between 34 Mbit/s and 1 Gbit/s are routinely being deployed with latencies in

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5208-559: The Cold War , which had to be built and operated due to the large distance between West Germany and Berlin at the edge of the technical feasibility. In addition to the telephone network, also microwave relay links for the distribution of TV and radio broadcasts. This included connections from the studios to the broadcasting systems distributed across the country, as well as between the radio stations, for example for program exchange. Military microwave relay systems continued to be used into

5332-490: The English Channel using 10-foot (3 m) dishes. Telephony, telegraph, and facsimile data was transmitted over the bidirectional 1.7 GHz beams 40 miles (64 km) between Dover , UK, and Calais , France. The radiated power, produced by a miniature Barkhausen–Kurz tube located at the dish's focus, was one-half watt. A 1933 military microwave link between airports at St. Inglevert, France, and Lympne, UK,

5456-780: The English Channel was demonstrated in 1931, the development of radar in World War II provided the technology for practical exploitation of microwave communication. During the war, the British Army introduced the Wireless Set No. 10, which used microwave relays to multiplex eight telephone channels over long distances. A link across the English Channel allowed General Bernard Montgomery to remain in continual contact with his group headquarters in London. In

5580-584: The IEEE 802.16 family of wireless-networks standards ratified by the WiMAX Forum. (Similarly, Wi-Fi refers to interoperable implementations of the IEEE 802.11 Wireless LAN standards certified by the Wi-Fi Alliance .) WiMAX Forum certification allows vendors to sell fixed or mobile products as WiMAX certified, thus ensuring a level of interoperability with other certified products, as long as they fit

5704-604: The LTE Advanced standard. WiMAX was initially designed to provide 30 to 40 megabit-per-second data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations. WiMAX release 2.1, popularly branded as WiMAX 2+ , is a backwards-compatible transition from previous WiMAX generations. It is compatible and interoperable with TD-LTE . Newer versions, still backward compatible, include WiMAX release 2.2 (2014) and WiMAX release 3 (2021, adds interoperation with 5G NR ). WiMAX refers to interoperable implementations of

5828-410: The efficiency of scale . Conduits that are located closer to the endpoint, or end-user, do not individually have as many users supporting them. Even though they are smaller, each has the overhead of an "installation" obtaining and maintaining a suitable path over which the resource can flow. The funding and resources supporting these smaller conduits tend to come from the immediate locale. This can have

5952-409: The line of sight , so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter , but such systems are expensive and generally used only in specialist roles. Although an experimental 40-mile (64 km) microwave telecommunication link across

6076-430: The telecommunications , cable television and internet industries refers to the final leg of a telecommunications network that delivers telecommunication services to retail end-users (customers). More specifically, last mile describes the portion of the telecommunications network chain that physically reaches the end-user's premises. Examples are the copper wire subscriber lines connecting landline telephones to

6200-400: The 1950s a unit of the US telephone carrier, AT&T Long Lines , built a transcontinental system of microwave relay links across the US which grew to carry the majority of US long distance telephone traffic, as well as television network signals. The main motivation in 1946 to use microwave radio instead of cable was that a large capacity could be installed quickly and at less cost. It

6324-615: The 1950s, networks of microwave relay links, such as the AT&;T Long Lines system in the U.S., carried long-distance telephone calls and television programs between cities. The first system, dubbed TDX and built by AT&T, connected New York and Boston in 1947 with a series of eight radio relay stations. Through the 1950s, they deployed a network of a slightly improved version across the U.S., known as TD2 . These included long daisy-chained links that traversed mountain ranges and spanned continents. The launch of communication satellites in

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6448-489: The 1960s, when many of these systems were supplanted with tropospheric scatter or communication satellite systems. When the NATO military arm was formed, much of this existing equipment was transferred to communications groups. The typical communications systems used by NATO during that time period consisted of the technologies which had been developed for use by the telephone carrier entities in host countries. One example from

6572-824: The 1970s and 80s, and the introduction of long-distance fibre optic systems in the 1980s and especially 90s led to the rapid rundown of the relay networks, most of which are abandoned. In recent years, there has been an explosive increase in use of the microwave spectrum by new telecommunication technologies such as wireless networks , and direct-broadcast satellites which broadcast television and radio directly into consumers' homes. Larger line-of-sight links are once again popular for handing connections between mobile telephone towers, although these are generally not organized into long relay chains. Microwaves are widely used for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at

6696-411: The 1970s provided a cheaper alternative. Much of the transcontinental traffic is now carried by satellites and optical fibers , but microwave relay remains important for shorter distances. Because in microwave transmission the waves travel in narrow beams confined to a line-of-sight path from one antenna to the other, they do not interfere with other microwave equipment, so nearby microwave links can use

6820-406: The 1990s. Frequency bands below 10 GHz, and above all, the information to be transmitted, were a stream containing a fixed capacity block. The target was to supply the requested availability for the whole block ( Plesiochronous digital hierarchy , PDH, or synchronous digital hierarchy , SDH). Fading and/or multipath affecting the link for short time period during the day had to be counteracted by

6944-533: The British Army used the Wireless Set Number 10 in this role during World War II. The need for radio relay did not really begin until the 1940s exploitation of microwaves , which traveled by line of sight and so were limited to a propagation distance of about 40 miles (64 km) by the visual horizon. After the war, telephone companies used this technology to build large microwave radio relay networks to carry long-distance telephone calls. During

7068-525: The IMT-2000 set of standards. This enables spectrum owners (specifically in the 2.5–2.69 GHz band at this stage) to use WiMAX equipment in any country that recognizes the IMT-2000. WiMAX cannot deliver 70  Mbit/s over 50 km (31 mi). Like all wireless technologies, WiMAX can operate at higher bitrates or over longer distances but not both. Operating at the maximum range of 50 km (31 mi) increases bit error rate and thus results in

7192-560: The North American region in terms of 4G broadband wireless subscribers. There were around 1.7 million pre-WiMAX and WiMAX customers in Asia – 29% of the overall market – compared to 1.4 million in the US and Canada. The WiMAX Forum has proposed an architecture that defines how a WiMAX network can be connected with an IP based core network, which is typically chosen by operators that serve as Internet Service Providers (ISP); Nevertheless,

7316-476: The RF signal travels through. Modulation is chosen to be more spectrally efficient (more bits per OFDM / SOFDMA symbol). That is, when the bursts have a high signal strength and a high carrier to noise plus interference ratio (CINR), they can be more easily decoded using digital signal processing (DSP). In contrast, operating in less favorable environments for RF communication, the system automatically steps down to

7440-491: The USA is the RCA CW-20A 1–2 GHz microwave relay system which utilized flexible UHF cable rather than the rigid waveguide required by higher frequency systems, making it ideal for tactical applications. The typical microwave relay installation or portable van had two radio systems (plus backup) connecting two line of sight sites. These radios would often carry 24 telephone channels frequency-division multiplexed on

7564-470: The WiMAX BS provide seamless integration capabilities with other types of architectures as with packet switched Mobile Networks. The WiMAX forum proposal defines a number of components, plus some of the interconnections (or reference points) between these, labeled R1 to R5 and R8: The functional architecture can be designed into various hardware configurations rather than fixed configurations. For example,

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7688-554: The WiMAX Forum published three licensed spectrum profiles: 2.3 GHz, 2.5 GHz and 3.5 GHz, in an effort to drive standardisation and decrease cost. In the US, the biggest segment available was around 2.5 GHz, and is already assigned, primarily to Sprint Nextel and Clearwire . Elsewhere in the world, the most-likely bands used will be the Forum approved ones, with 2.3 GHz probably being most important in Asia. Some countries in Asia like India and Indonesia will use

7812-466: The WiMAX gateways that are offered by manufactures such as these are stand-alone self-install indoor units. Such devices typically sit near the customer's window with the best signal, and provide: Indoor gateways are convenient, but radio losses mean that the subscriber may need to be significantly closer to the WiMAX base station than with professionally installed external units. Outdoor units are roughly

7936-473: The WiMAX standard rather than being added on as carrier Ethernet is to Ethernet . On May 7, 2008, in the United States, Sprint Nextel , Google , Intel , Comcast , Bright House , and Time Warner announced a pooling of an average of 120 MHz of spectrum and merged with Clearwire to market the service. The new company hoped to benefit from combined services offerings and network resources as

8060-752: The WiMAX technology due to financial circumstances, instead, along with its network partner Clearwire , Sprint Nextel rolled out a 4G network having decided to shift and utilize LTE 4G technology instead. WiMAX is based upon IEEE 802.16e-2005 , approved in December 2005. It is a supplement to the IEEE Std 802.16-2004, and so the actual standard is 802.16-2004 as amended by 802.16e-2005. Thus, these specifications need to be considered together. IEEE 802.16e-2005 improves upon IEEE 802.16-2004 by: SOFDMA (used in 802.16e-2005) and OFDM256 (802.16d) are not compatible thus equipment will have to be replaced if an operator

8184-441: The ability to derive new value from simple concepts through technological innovation – and a warning that copper communications infrastructure is beginning to offer diminishing returns for continued investment. However one of the largest costs associated with maintaining an ageing copper infrastructure is that of truck roll - sending engineers to physically test, repair, replace and provide new copper connections, and this cost

8308-427: The accompanying distortions. Wireless systems have an advantage over wired systems in last mile applications in not requiring lines to be installed. However, they also have a disadvantage in that their unguided nature makes them more susceptible to unwanted noise and signals. Spectral reuse can therefore be limited. Visible and infrared light waves are much shorter than radio frequency waves. Their use to transmit data

8432-643: The addition of periodic amplification, there is some maximum length beyond which all of these systems fail to deliver an adequate S/N ratio to support information flow. Dielectric optical fiber systems support heavier flow at higher cost. Traditional wired local area networking systems require copper coaxial cable or a twisted pair to be run between or among two or more of the nodes in the network. Common systems operate at 100 Mbit/s, and newer ones also support 1000 Mbit/s or more. While length may be limited by collision detection and avoidance requirements, signal loss and reflections over these lines also define

8556-431: The advantage of a "small-government model". That is, the management and resources for these conduits is provided by local entities and therefore can be optimized to achieve the best solutions in the immediate environment and also to make best use of local resources. However, the lower operating efficiencies and relatively greater installation expenses, compared with the transfer capacities, can cause these smaller conduits, as

8680-399: The architecture is flexible enough to allow remote/mobile stations of varying scale and functionality and Base Stations of varying size – e.g. femto, pico, and mini BS as well as macros. WiMAX 2.1 and above can be integrated with a LTE TDD network and perform handovers from/to LTE TDD. WiMAX 3 expands the integration to 5G NR . There is no uniform global licensed spectrum for WiMAX, however

8804-400: The area and reception issues arising from the use of nearby land (such as in manufacturing and forestry) are important issues to consider when planning radio links. In the planning process, it is essential that "path profiles" are produced, which provide information about the terrain and Fresnel zones affecting the transmission path. The presence of a water surface, such as a lake or river, along

8928-419: The atmosphere including fog and rain, particularly over longer paths, can greatly restrict their use for last-mile wireless communications. Radio frequencies (RF), from low frequencies through the microwave region, have wavelengths much longer than visible light. Although this means that it is not possible to focus the beams nearly as tightly as for light, it also means that the aperture or "capture area" of even

9052-424: The available frequencies will be dynamically assigned (resulting in dynamic changes to the available bandwidth.) This could lead to cluttered frequencies with slow response times or lost frames. As a result, the system has to be initially designed in consensus with the base station product team to accurately project frequency use, interference, and general product functionality. The Asia-Pacific region has surpassed

9176-422: The connections among LANs could be spread over one or even several LANs. As each new LAN, or subnet, was added, the new subnet's constituents enjoyed access to the greater network. At the same time the new subnet enabled access to any network or networks with which it was already networked. Thus the growth became a mutually inclusive or "win-win" event. In general, economy of scale makes an increase in capacity of

9300-407: The deployment phase and providing a critical foundation for future regional commerce. Fixed copper lines have been subject to theft due to the value of copper, but optical fibers make unattractive targets. Optical fibers cannot be converted into anything else, whereas copper can be recycled without loss . Mobile CDN coined the term the ' mobile mile' to categorize the last mile connection when

9424-865: The detrimental factors mentioned in this section, collectively known as path loss , make it necessary to compute suitable power margins, in order to maintain the link operative for a high percentage of time, like the standard 99.99% or 99.999% used in 'carrier class' services of most telecommunication operators. The longest known microwave radio relay crosses the Red Sea with a 360 km (220 mi) hop between Jebel Erba (2,170 m (7,120 ft) a.s.l., 20°44′46.17″N 36°50′24.65″E  /  20.7461583°N 36.8401806°E  / 20.7461583; 36.8401806 , Sudan) and Jebel Dakka (2,572 m (8,438 ft) a.s.l., 21°5′36.89″N 40°17′29.80″E  /  21.0935806°N 40.2916111°E  / 21.0935806; 40.2916111 , Saudi Arabia). The link

9548-542: The diversity architecture. During 1990s microwave radio links begun widely to be used for urban links in cellular network . Requirements regarding link distance changed to shorter hops (less than 10 km (6.2 mi), typically 3 to 5 km (1.9 to 3.1 mi)), and frequency increased to bands between 11 and 43 GHz and more recently, up to 86 GHz (E-band). Furthermore, link planning deals more with intense rainfall and less with multipath, so diversity schemes became less used. Another big change that occurred during

9672-494: The economics of information transfer may be viewed in terms of the economics of the transfer of ICE. Effective last-mile conduits must: In addition to these factors, a good solution to the last-mile problem must provide each user: Wired systems provide guided conduits for Information-Carrying Energy (ICE). They all have some degree of shielding, which limits their susceptibility to external noise sources. These transmission lines have losses which are proportional to length. Without

9796-852: The first WiMAX enabled mobile phone , the Max 4G , on November 12, 2008. The device was only available to certain markets in Russia on the Yota network until 2010. HTC and Sprint Nextel released the second WiMAX enabled mobile phone, the HTC Evo 4G , March 23, 2010 at the CTIA conference in Las Vegas. The device, made available on June 4, 2010, is capable of both EV-DO(3G) and WiMAX(pre-4G) as well as simultaneous data & voice sessions. Sprint Nextel announced at CES 2012 that it will no longer be offering devices using

9920-473: The fixed orthogonal frequency-division multiplexing (OFDM) version with 256 sub-carriers (of which 200 are used) in 802.16d. More advanced versions, including 802.16e, also bring multiple antenna support through MIMO . (See WiMAX MIMO ) This brings potential benefits in terms of coverage, self installation, power consumption, frequency re-use and bandwidth efficiency. WiMax is the most energy-efficient pre-4G technique among LTE and HSPA+ . The WiMAX MAC uses

10044-414: The freedom to move around without trailing cables. These are often seen on the touchlines of sports fields on Steadicam systems. Terrestrial microwave relay links are limited in distance to the visual horizon, a few tens of miles or kilometers depending on tower height. Tropospheric scatter ("troposcatter" or "scatter") was a technology developed in the 1950s to allow microwave communication links beyond

10168-453: The horizon, to a range of several hundred kilometers. The transmitter radiates a beam of microwaves into the sky, at a shallow angle above the horizon toward the receiver. As the beam passes through the troposphere a small fraction of the microwave energy is scattered back toward the ground by water vapor and dust in the air. A sensitive receiver beyond the horizon picks up this reflected signal. Signal clarity obtained by this method depends on

10292-440: The industry, prior attempts to form partnerships among wireless and cable companies had generally failed to lead to significant benefits for the participants. Other analysts at IDC favored the deal, pointing out that as wireless progresses to higher bandwidth, it inevitably competes more directly with cable, DSL and fiber, inspiring competitors into collaboration. Also, as wireless broadband networks grow denser and usage habits shift,

10416-399: The larger capacity ones. These common attributes are shown to the right. The high-capacity conduits in these systems tend to also have in common the ability to efficiently transfer the resource over a long distance. Only a small fraction of the resource being transferred is wasted, lost, or misdirected. The same cannot necessarily be said of lower-capacity conduits. One reason has to do with

10540-420: The last decade was an evolution toward packet radio transmission. Therefore, new countermeasures, such as adaptive modulation , have been adopted. The emitted power is regulated for cellular and microwave systems. These microwave transmissions use emitted power typically from 0.03 to 0.30 W, radiated by a parabolic antenna on a narrow beam diverging by a few degrees (1 to 3-4). The microwave channel arrangement

10664-450: The last-mile problem, satellite systems have application and sharing limitations. The ICE which they transmit must be spread over a relatively large geographical area. This causes the received signal to be relatively small, unless very large or directional terrestrial antennas are used. A parallel problem exists when a satellite is receiving. In that case, the satellite system must have a very great information capacity in order to accommodate

10788-403: The local telephone exchange ; coaxial cable service drops carrying cable television signals from utility poles to subscribers' homes, and cell towers linking local cell phones to the cellular network . The word "mile" is used metaphorically; the length of the last mile link may be more or less than a mile. Because the last mile of a network to the user is conversely the first mile from

10912-414: The longest distance and highest capacity backbone connections. In recent years, the capacity of fiber-optic communication , aided by a supporting industry, has resulted in an expansion of raw capacity, so much so that in the United States a large amount of installed fiber infrastructure is not being used because it is currently excess capacity " dark fiber ". This excess backbone capacity exists in spite of

11036-440: The lower carrier frequencies are not able to support the high information bandwidths, which are required by Shannon's equation when the practical limits of S/N have been reached. For the above reasons, wireless radio systems are optimal for lower-information-capacity broadcast communications delivered over longer paths. For high-information capacity, highly-directive point-to-point over short ranges, wireless light-wave systems are

11160-518: The microwave band has a bandwidth 30 times that of all the rest of the radio spectrum below it. A disadvantage is that microwaves are limited to line of sight propagation; they cannot pass around hills or mountains as lower frequency radio waves can. Microwave radio transmission is commonly used in point-to-point communication systems on the surface of the Earth, in satellite communications , and in deep space radio communications . Other parts of

11284-409: The microwave beam can be received. At the turn of the century, microwave radio relay systems were used increasingly in portable radio applications. The technology is particularly suited to this application because of lower operating costs, a more efficient infrastructure , and provision of direct hardware access to the portable radio operator. A microwave link is a communications system that uses

11408-438: The microwave carrier (i.e. Lenkurt 33C FDM). Any channel could be designated to carry up to 18 teletype communications instead. Similar systems from Germany and other member nations were also in use. Long-distance microwave relay networks were built in many countries until the 1980s, when the technology lost its share of fixed operation to newer technologies such as fiber-optic cable and communication satellites , which offer

11532-458: The microwave radio band are used for radars , radio navigation systems, sensor systems, and radio astronomy . The next higher frequency band of the radio spectrum , between 30 GHz and 300 GHz, are called " millimeter waves " because their wavelengths range from 10 mm to 1 mm. Radio waves in the millimeter wave band are strongly attenuated by the gases of the atmosphere , which limits their practical transmission distance to

11656-619: The mobile profiles are TDD only. The fixed profiles have channel sizes of 3.5 MHz, 5 MHz, 7 MHz and 10 MHz. The mobile profiles are 5 MHz, 8.75 MHz and 10 MHz. (Note: the 802.16 standard allows a far wider variety of channels, but only the above subsets are supported as WiMAX profiles.) Since October 2007, the Radio communication Sector of the International Telecommunication Union (ITU-R) has decided to include WiMAX technology in

11780-425: The most numerous and thus the most expensive part of the system, as well as having to interface with a wide variety of user equipment, are the most difficult to upgrade to new technology. For example, telephone trunklines that carry phone calls between switching centers are made of modern optical fiber , but the last mile is typically twisted pair wires, a technology which has essentially remained unchanged for over

11904-516: The most part, higher-capacity systems, such as two-way video communications or terrestrial microwave telephone and data trunks, have been limited and confined to UHF or microwave and to point-point paths. Higher capacity systems such as third-generation cellular telephone systems require a large infrastructure of more closely spaced cell sites in order to maintain communications within typical environments, where path losses are much greater than in free space and which also require omnidirectional access by

12028-636: The most useful. Historically, most high-information-capacity broadcast has used lower frequencies, generally no higher than the UHF television region, with television itself being a prime example. Terrestrial television has generally been limited to the region above 50 MHz where sufficient information bandwidth is available, and below 1,000 MHz, due to problems associated with increased path loss, as mentioned above. Two-way communication systems have primarily been limited to lower-information-capacity applications, such as audio, facsimile, or radioteletype . For

12152-666: The need for increased backhaul and media services accelerate, therefore the opportunity to leverage high bandwidth assets was expected to increase. The Aeronautical Mobile Airport Communication System (AeroMACS) is a wireless broadband network for the airport surface intended to link the control tower, aircraft, and fixed assets. In 2007, AeroMACS obtained a worldwide frequency allocation in the 5 GHz aviation band. As of 2018, there were 25 AeroMACS deployments in 8 countries, with at least another 25 deployments planned. IEEE 802.16REVd and IEEE 802.16e standards support both time-division duplexing and frequency-division duplexing as well as

12276-494: The next biggest to AT&T. Both of these companies stated their intention of supporting LTE , a technology which competes directly with WiMAX. EU commissioner Viviane Reding has suggested re-allocation of 500–800 MHz spectrum for wireless communication, including WiMAX. WiMAX profiles define channel size, TDD/FDD and other necessary attributes in order to have interoperating products. The current fixed profiles are defined for both TDD and FDD profiles. At this point, all of

12400-419: The omnipresence of noise in information systems sets a minimum signal-to-noise ratio (shortened as S/N) requirement in a channel, even when adequate spectral bandwidth is available. Since the integral of the rate of information transfer with respect to time is information quantity, this requirement leads to a corresponding minimum energy per bit . The problem of sending any given amount of information across

12524-447: The order of 1 ms. In many cases, operators are aggregating sites using wireless technology and then presenting traffic on to fiber networks where convenient. WiMAX in this application competes with microwave radio , E-line and simple extension of the fiber network itself. WiMAX directly supports the technologies that make triple-play service offerings possible (such as quality of service and multicast ). These are inherent to

12648-416: The path also must be taken into consideration since it can reflect the beam, and the direct and reflected beam can interfere with each other at the receiving antenna, causing multipath fading. Multipath fades are usually deep only in a small spot and a narrow frequency band, so space and/or frequency diversity schemes can be applied to mitigate these effects. The effects of atmospheric stratification cause

12772-431: The post-war era, the development of microwave technology was rapid, which led to the construction of several transcontinental microwave relay systems in North America and Europe. In addition to carrying thousands of telephone calls at a time, these networks were also used to send television signals for cross-country broadcast, and later, computer data. Communication satellites took over the television broadcast market during

12896-480: The previous voiceband systems. These methods are not based on altering the fundamental physical properties and limitations of the medium, which, apart from the introduction of twisted pairs , are no different today than when the first telephone exchange was opened in 1877 by the Bell Telephone Company. The history and long life of copper-based communications infrastructure is both a testament to

13020-653: The publication by Johann Mattausch in the Austrian journal, Zeitschrift für Elektrotechnik. But his proposal was primitive and not suitable for practical use. The first experiments with radio repeater stations to relay radio signals were done in 1899 by Emile Guarini-Foresio. However the low frequency and medium frequency radio waves used during the first 40 years of radio proved to be able to travel long distances by ground wave and skywave propagation. In 1931, an Anglo-French consortium headed by Andre C. Clavier demonstrated an experimental microwave relay link across

13144-556: The radio path to bend downward in a typical situation so a major distance is possible as the earth equivalent curvature increases from 6,370 km (3,960 mi) to about 8,500 km (5,300 mi) (a 4/3 equivalent radius effect). Rare events of temperature, humidity and pressure profile versus height, may produce large deviations and distortion of the propagation and affect transmission quality. High-intensity rain and snow making rain fade must also be considered as an impairment factor, especially at frequencies above 10 GHz. All of

13268-408: The receiving antenna. This use of tightly-focused direct beams allows microwave transmitters in the same area to use the same frequencies, without interfering with each other as lower frequency radio waves would. This frequency reuse conserves scarce radio spectrum bandwidth. Another advantage is that the high frequency of microwaves gives the microwave band a very large information-carrying capacity;

13392-399: The relatively low costs associated with the deployment of a WiMAX network (in comparison with 3G , HSDPA , xDSL , HFC or FTTx ), it is now economically viable to provide last-mile broadband Internet access in remote locations. Mobile WiMAX was a replacement candidate for cellular phone technologies such as GSM and CDMA , or can be used as an overlay to increase capacity. Fixed WiMAX

13516-407: The same frequencies. The antennas must therefore be highly directional (high gain ), and are installed in elevated locations such as large radio towers in order to be able to avoid the obstructions closer to the ground and transmit across long distances. Typical types of antenna used in radio relay link installations are parabolic antennas , dielectric lens, and horn-reflector antennas , which have

13640-474: The same profile. The original IEEE 802.16 standard (now called "Fixed WiMAX") was published in 2001. WiMAX adopted some of its technology from WiBro , a service marketed in Korea. Mobile WiMAX (originally based on 802.16e-2005) is the revision that was deployed in many countries and is the basis for future revisions such as 802.16m-2011. WiMAX was sometimes referred to as "Wi-Fi on steroids" and can be used for

13764-423: The scheduling algorithm can also be more bandwidth efficient. The scheduling algorithm also allows the base station to control QoS parameters by balancing the time-slot assignments among the application needs of the subscriber station. As a standard intended to satisfy needs of next-generation data networks ( 4G ), WiMAX is distinguished by its dynamic burst algorithm modulation adaptive to the physical environment

13888-403: The signal field cause unwanted attenuation . High mountain peaks or ridges are often ideal positions for the antennas. In addition to the use of conventional repeaters with back-to-back radios transmitting on different frequencies, obstructions in microwave paths can also be dealt with by using Passive repeater or on-frequency repeaters. Obstacles, the curvature of the Earth, the geography of

14012-457: The simplest, omnidirectional antenna is significantly larger than that of a lens in any feasible optical system. This characteristic results in greatly increased attenuation or "path loss" for systems that are not highly directional. Actually, the term path loss is something of a misnomer because no energy is lost on a free-space path. Rather, it is merely not received by the receiving antenna. The apparent reduction in transmission, as frequency

14136-606: The size of a laptop PC, and their installation is comparable to the installation of a residential satellite dish . A higher- gain directional outdoor unit will generally result in greatly increased range and throughput but with the obvious loss of practical mobility of the unit. USB can provide connectivity to a WiMAX network through a dongle . Generally these devices are connected to a notebook or net book computer. Dongles typically have omnidirectional antennas which are of lower gain compared to other devices. As such these devices are best used in areas of good coverage. HTC announced

14260-424: The spectrum available for reverse information flow and achievable S/N are limited. As was done for initial unidirectional TV communication, cable loss is mitigated through the use of periodic amplifiers within the system. These factors set an upper limit on per-user information capacity, particularly when many users share a common section of cable or access network . Fiber offers high information capacity and after

14384-425: The trend of increasing per-user data rates and overall quantity of data. Initially, only the inter-LAN connections were high speed. End-users used existing telephone lines and modems, which were capable of data rates of only a few hundred bit/s . Now almost all end users enjoy access at 100 or more times those early rates. Before considering the characteristics of existing last-mile information delivery mechanisms, it

14508-718: The turn of the 21st century became the deployed medium of choice (" Fiber to the x ") given its scalability in the face of the increasing bandwidth requirements of modern applications. In 2004, according to Richard Lynch, Executive Vice President and Chief Technology Officer of the telecom giant Verizon , the company saw the world moving toward vastly higher bandwidth applications as consumers loved everything broadband had to offer and eagerly devoured as much as they could get, including two-way, user-generated content. Copper and coaxial networks would not – in fact, could not – satisfy these demands, which precipitated Verizon's aggressive move into fiber-to-the-home via FiOS . Fiber

14632-461: The use of the most robust burst setting; that is, the profile with the largest MAC frame allocation trade-off requiring more symbols (a larger portion of the MAC frame) to be allocated in transmitting a given amount of data than if the client were closer to the base station. The client's MAC frame and their individual burst profiles are defined as well as the specific time allocation. However, even if this

14756-513: The user's premises to the outside world when the user is sending data, the term first mile is also alternatively used. The last mile is typically the speed bottleneck in communication networks; its bandwidth effectively limits the amount of data that can be delivered to the customer. This is because retail telecommunication networks have the topology of " trees ", with relatively few high capacity "trunk" communication channels branching out to feed many final mile "twigs". The final mile links, being

14880-405: The users. For information delivery to end users, satellite systems, by nature, have relatively long path lengths, even for low earth-orbiting satellites. They are also very expensive to deploy and therefore each satellite must serve many users. Additionally, the very long paths of geostationary satellites cause information latency that makes many real-time applications unfeasible. As a solution to

15004-560: The widespread adoption of the Internet , the need for economical high-speed access by end-users located at millions of locations has ballooned as well. As requirements have changed, the existing systems and networks that were initially pressed into service for this purpose have proven to be inadequate. To date, although a number of approaches have been tried, no single clear solution to the 'last mile problem' has emerged. As expressed by Shannon's equation for channel information capacity ,

15128-662: Was born out of the need to connect several of these LANs together, particularly as related to common projects among the United States Department of Defense , industry and some academic institutions. ARPANET came into being to further these interests. In addition to providing a way for multiple computers and users to share a common inter-LAN connection, the TCP/IP protocols provided a standardized way for dissimilar computers and operating systems to exchange information over this inter-network. The funding and support for

15252-445: Was built in 1979 by Telettra to transmit 300 telephone channels and one TV signal, in the 2 GHz frequency band. (Hop distance is the distance between two microwave stations). Previous considerations represent typical problems characterizing terrestrial radio links using microwaves for the so-called backbone networks: hop lengths of a few tens of kilometers (typically 10 to 60 km (6.2 to 37.3 mi)) were largely used until

15376-413: Was expected at that time that the annual operating costs for microwave radio would be greater than for cable. There were two main reasons that a large capacity had to be introduced suddenly: Pent-up demand for long-distance telephone service, because of the hiatus during the war years, and the new medium of television, which needed more bandwidth than radio. The prototype was called TDX and was tested with

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