Mobile WiMAX the next revolution in wireless technology
WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-multipoint links to portable and fully mobile internet access. The technology provides up to 10 Mbps [1] broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX[2] as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL".
The bandwidth and range of WiMAX make it suitable for the following potential applications:
Connecting Wi-Fi hotspots to the Internet.
Providing a wireless alternative to cable and DSL for "last mile" broadband access.
Providing data, telecommunications and IPTV services (triple-play).
Providing a source of Internet connectivity as part of a business continuity plan. That is, if a business has both a fixed and a wireless Internet connection, especially from unrelated providers, they are unlikely to be affected by the same service outage.
Providing portable connectivity
Comparison with Wi-Fi
Comparisons and confusion between WiMAX and Wi-Fi are frequent because both are related to wireless connectivity and Internet access.
WiMAX is a long range system, covering many kilometers, that uses licensed or unlicensed spectrum to deliver a point-to-point connection to the Internet.
Different 802.16 standards provide different types of access, from portable (similar to a cordless phone) to fixed (an alternative to wired access, where the end user's wireless termination point is fixed in location.)
Wi-Fi uses unlicensed spectrum to provide access to a network.
Wi-Fi is more popular in end user devices.
WiMAX and Wi-Fi have quite different quality of service (QoS) mechanisms:
WiMAX uses a QoS mechanism based on connections between the base station and the user device. Each connection is based on specific scheduling algorithms.
Wi-Fi has a QoS mechanism similar to fixed Ethernet, where packets can receive different priorities based on their tags. For example VoIP traffic may be given priority over web browsing.
Wi-Fi runs on the Media Access Control's CSMA/CA protocol, which is connectionless and contention based, whereas WiMAX runs a connection-oriented MAC.
Both 802.11 and 802.16 define Peer-to-Peer (P2P) and ad hoc networks, where an end user communicates to users or servers on another Local Area Network (LAN) using its access point or base station.
Spectral efficiency
One of the significant advantages of advanced wireless systems such as WiMAX is spectral efficiency. For example, 802.16-2004 (fixed) has a spectral efficiency of 3.7 (bit/s)/Hertz, and other 3.5–4G wireless systems offer spectral efficiencies that are similar to within a few tenths of a percent. The notable advantage of WiMAX comes from combining SOFDMA with smart antenna technologies. This multiplies the effective spectral efficiency through multiple reuse and smart network deployment topologies. The direct use of frequency domain organization simplifies designs using MIMO-AAS compared to CDMA/WCDMA methods, resulting in more effective systems.
Mobile handset applications
Sprint Nextel announced in mid-2006 that it would invest about US$ 5 billion in a WiMAX technology buildout over the next few years[7] ($5.29 billion in real terms[8]). Since that time Sprint has faced many setbacks, that have resulted in steep quarterly losses. On May 7, 2008, 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 form a company which will take the name Clear. The new company hopes to benefit from combined services offerings and network resources as a springboard past its competitors. The cable companies will provide media services to other partners while gaining access to the wireless network as a Mobile virtual network operator. Google will contribute Android handset device development and applications and will receive revenue share for advertising and other services they provide. Sprint and Clearwire gain a majority stock ownership in the new venture and ability to access between the new Clear and Sprint 3G networks. Some details remain unclear including how soon and in what form announced multi-mode WiMAX and 3G EV-DO devices will be available. This raises questions that arise for availability of competitive chips that require licensing of Qualcomm's IPR.
HTC currently has a WiMAX device in development. Codenamed, "Supersonic", the HTC A9292 has been deemed considerably sluggish as of January 2010, meaning the device is in early stages of development. The estimated release date is sometime in the second half of 2010.[9]
Some analysts have questioned how the deal will work out: Although fixed-mobile convergence has been a recognized factor in the industry, prior attempts to form partnerships among wireless and cable companies have generally failed to lead to significant benefits to the participants. Other analysts point out that as wireless progresses to higher bandwidth, it inevitably competes more directly with cable and DSL, thrusting competitors into bed together. Also, as wireless broadband networks grow denser and usage habits shift, the need for increased backhaul and media service will accelerate, therefore the opportunity to leverage cable assets is expected to increase.
What is WiMAX Mobile or 802.16e?
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.
Mobile WiMAX¹ is the next revolution in wireless technology that will enable pervasive, high-speed connectivity to meet the ever-increasing demand for broadband Internet on the go. Delivering the next leap in the mobile network evolution with fourth generation (4G) wireless, WiMAX will drive a wide array of devices well beyond what's available today, including notebooks, Mobile Internet Devices (MIDs), smart phones, consumer electronic devices, and more.
The WiMAX future
The only network optimized specifically for mobile broadband Internet, WiMAX is based on a set of global standards covering fixed, portable, and mobile deployments on an open network that will help drive and leverage the openness of the Internet, as opposed to prior generation's closed systems.
The low-cost, all-IP network architecture and backwards compatibility with existing 2G and 3G cellular network deployments makes WiMAX easier and more cost-effective to deploy and operate than current mobile wireless data solutions. As a result, it has already garnered broad support from leading operators—both wireline and wireless—and device manufacturers around the world.
With the ability to carry more data traffic than current wireless networks, WiMAX is intended to meet increasing demands for mobile data. WiMAX will also be the first 4G technology to combine the following standards-based technologies:
Efficient support for many simultaneous users with Orthogonal Frequency Division Multiple Access (OFDMA)
Increased throughput and range with Multiple Input/Multiple Output (MIMO) smart antenna technology using multiple antennas to carry more data traffic than current networks
Based on the IEEE 802.16e standard, mobile WiMAX is designed to deliver superior data rates and scalability, lower costs, and reduced network complexity. As the first new technology to be added to the International Mobile Telecommuncations-2000 (IMT-2000 a globally recognized group of mobile wireless interfaces) set of standards in nearly a decade, WiMAX is about to revolutionize and mobilize the way we connect around the globe.
Key Benefits of Mobile WiMAX
Improved Air Interface: The Mobile WiMAX air interface utilizes
Orthogonal Frequency Division Multiple Access (OFDMA) for improved
multipath performance in non-line-of-sight environments
and high flexibility in allocating resources to users with different
data rate requirements.
High Data Rates: A variety of antenna techniques are supported
by Mobile WiMAX to increase throughput, especially at the
cell edge. For example, the use of multiple-input multiple-output
(MIMO) antenna techniques combined with flexible sub-channelization
schemes, adaptive modulation and variable coding rates enable
Mobile WiMAX technology to support peak downlink (DL) data
rates up to 46 Mbps per sector and peak uplink (UL) data rates up
to 14 Mbps per sector in a 10 MHz channel (DL 2x2 MIMO, 3:1
DL/UL ratio; UL 1x2 collaborative MIMO; 1:1 ratio).1
Quality of Service (QoS): The fundamental premise of the IEEE
802.16e media access control (MAC) architecture is QoS. Mobile
WiMAX QoS features enable operators to optimize network performance
depending on the service type (e.g., voice, video, gaming)
and the user's service level. The standard defines service flows
which can be mapped to fine, granular IP sessions or coarsely
differentiated services code points to enable end-to-end IP based
QoS. Additionally, sub-channelization and media access protocol
(MAP) based signaling schemes provide a flexible mechanism for
optimal scheduling of broadcast and unicast traffic on a frame-byframe
basis.
Scalability: Mobile WiMAX technology utilizes scalable OFDMA
(SOFDMA) and, according to the initial Mobile WiMAX system
profiles, has the capability to operate in channel sizes of 5, 7,
8.75, and 10 MHz to comply with various spectrum allocations
worldwide.
Security: Mobile WiMAX technology incorporates the most
advanced security features currently used in IEEE 802 wireless
access systems. These include Extensible Authentication Protocol
(EAP)-based authentication, Advanced Encryption Standard (AES)-
based authenticated encryption, Cipher-based Message Authentication
Code (CMAC) and Hashed Message Authentication Code
Mobility: Mobile WiMAX technology supports optimized handover
schemes with latencies less than 50 ms to help ensure
real-time applications such as Voice over Internet Protocol (VoIP)
are efficiently supported without service degradation. Flexible key
management schemes help assure security is maintained during
handover.
Mobile WiMAX does not Mandate Mobility
As stated earlier, Mobile WiMAX is equally applicable to fixed
as well as mobile environments. This is due to the fact that the
requirements for a fixed device are a subset of those for a mobile
device. The additional features enabling mobility naturally
extend WiMAX broadband wireless access from the fixed to the
mobile case.
(HMAC)-based control message protection schemes.
Christian Argenis Umaña Zambrano
Ci:17678077
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