This weblog is going to be finished and it is time to conclude it.
First, the main purpose of this weblog is to introduce the developing history and the future of 802.11 standards which is illustrated in the beginning of this blog. As a student who did not know any thing about 802.11 standards before, my acquaintance procedure is quite similar to the arrangement of this weblog. After finishing this weblog, I get understand on the framework of 802.11 standards no matter from the technology aspect or the market aspect.
The first part of this weblog is to introduce the 802.11 standards briefly and globally.
So the first and the second posts are explaining the definition of 802.11 and the various amendments, respectively.
The second part of this weblog concentrates on three standards which are utilized most frequently recently (i.e. 802.11a/b/g). Among these articles, the prosperity of every amemdemts is depicted. Besides some general idea about each standard, the stating on the technology aspect including the comparison among them was also introduced.
The third part pay more attention to the application and market level of 802.11 standards. Analysis of the wifi market in China and my point of view on 802.11 market were the subtopics.
The forth part aimed at exploring the future of 802.11, and a new standard 802.11n becomes the researching object. I analysis the attributes and the peformance of 802.11n. Then I concentrating on the future application of this standard in the market.
After taking such an overview on 802.11 standard, I can conclude that this is a very successful standard. It brought in convenience and fulfilled the dream of wireless communication. When taking a look at the future of wi-fi, I can predict that it will still play an irreplaceable role in the wireless communication domain. Also the market behind this standard is huge and profitable.
Tuesday, July 3, 2007
Sunday, July 1, 2007
802.11n still in draft
Although 802.11n has such revolutionary advantages, it still need to be certificated by the Wi-Fi Alliance.
As I know, the certificate procedure has already started since June 2007. The alliance declare that they would like to certificate it to meet with the 802.11n draft standards. There are 11 lab carrying out this procedure all over the world. And the sencond step is to meet the former 820.11(a/b/g) standards.
As there are two years since the standards was proposed, experts predict that the final standards will be finished at the end of 2007. While in fact, this regulation could not be utilized until the end of 2008 according to the situation. Many company started to use the 802.11n draft as the standards for their products, which aimed at occupy the profitable market 802.11n bring in. Of course this will also introduce some risk, and the vendor will have to modify their standards according to the final version published by Wi-Fi Alliance.
The picutre below is the sticker on the 802.11n products nowadays, we can clearly see that there is a draft signature beside the 802.11n to indicate that it is still in draft.
As I know, the certificate procedure has already started since June 2007. The alliance declare that they would like to certificate it to meet with the 802.11n draft standards. There are 11 lab carrying out this procedure all over the world. And the sencond step is to meet the former 820.11(a/b/g) standards.
As there are two years since the standards was proposed, experts predict that the final standards will be finished at the end of 2007. While in fact, this regulation could not be utilized until the end of 2008 according to the situation. Many company started to use the 802.11n draft as the standards for their products, which aimed at occupy the profitable market 802.11n bring in. Of course this will also introduce some risk, and the vendor will have to modify their standards according to the final version published by Wi-Fi Alliance.
The picutre below is the sticker on the 802.11n products nowadays, we can clearly see that there is a draft signature beside the 802.11n to indicate that it is still in draft.
Performance of 802.11n
Since 802.11n is the next generation of WLAN standards, it must have some advantages over former standards. While in the notebook market today, there are already some 802.11n product like routers and netcards being utlized. So, in my point of view it will lead a revolutionary change in both the equipments and the wireless network throughput all over the world. For example, analyst firm ABI Research forecasts that 802.11n chipset shipments will increase from 93 million units in 2007 to about 1.1 billion units in 2012, dominating overall Wi-Fi shipments of 1.2 billion units.This considerable rate of growth reflects the fact that 802.11n promotes expansion of Wi-Fi into new market segments and applications in the home and in the enterprise. From different environment the poisitive aspect of 802.11n will be different. But there is one rule will not change, that is improvment!
Home Environment
With its increased coverage and throughput, 802.11n enables HD video and audio-visual (AV) multimedia applications in the home environment. Increased throughput and WMM capabilities enable more reliable transport of simultaneous voice and multimedia sessions.WMM certification helps ensure high quality of Wi-Fi calls, while the increased throughput and coverage of 802.11n provides sufficient bandwidth to transport multiple video streams to Wi-Fi enabled set-top boxes or TV sets around the house.
The high bandwidth and QoS of Wi-Fi CERTIFIED 802.11n draft 2.0 systems helps ensure that an internet connection can be reliably shared by the increasing number and type of Wi-Fi enabled devices in the home without degradation of service. Higher data rates of 802.11n also increase the throughput capacity of overlapping Wi-Fi networks.The increased range of 802.11n provides coverage of the entire house, reaching farther than the legacy technology and reducing “dead spots” or low-rate areas in the home. Even single-antenna mobile devices, such as Wi-Fi phones, will enjoy the benefits of increased range and throughput of Wi-Fi CERTIFIED 802.11n by virtue of the transmit diversity capabilities, such as Space Time Block Coding (STBC), Cyclic Shift Diversity (CSD) and Transmit Beamforming.Most network transactions, including voice and data services, will benefit significantly from the 802.11n frame aggregation technology. Printing files from PCs to printers, transferring files between PCs and network drives and sharing files between PCs, laptops and other devices on the network becomes more efficient with 802.11n thanks to frame aggregation.
Enterprise Environment
802.11n is enterprise-grade technology that will provide IT managers with nearly the same reliable service they have come to expect from their Ethernet networks. Mission-critical enterprise applications, such as Customer Relationship Management (CRM) and Enterprise Resource Planning (ERP) access, collaboration tools, voice and video conferencing, will all benefit from the increased throughput and range of 802.11n.The new efficiencies and enhancements of 802.11n on the MAC and PHY layers, combined with the WMM QoS capabilities, serve to improve the quality of VoIP and to increase the number of simultaneous calls on the airlink. Physical layer transmission enhancements of 802.11n, such as Space Time Block Coding (STBC), improve reception even for single receiver Wi-Fi phones by virtue of transmitting multiple copies of a data stream via multiple antennas. Multiple versions of the signal reaching the phone are received and processed with specialized decoding techniques to provide redundancy of signaling and optimize reception.Of significant benefit to the Enterprise is lower density of APs, made possible by the improved efficiencies in the MAC, enhancements in the PHY operation and longer reach. Due to faster physical layer transmissions, stations get on and off the air faster, improving the airlink efficiency. The MAC layer mechanisms such as block ACK and frame aggregation also improve the airlink efficiency by reducing the overhead of packet headers, inter-frame gaps and ACK transmissions.Legacy stations in the 802.11n network can benefit from better coverage provided by the 802.11n APs’ CSD and MRC techniques and they can also gain increased access to the airlink as the new 802.11n devices get on and off the air faster.
Campus and Municipal Networks
Campus and municipal networks typically operate in challenging environments where range is the biggest issue. 802.11n is well-equipped to improve the operating range even for single-antenna handheld devices used in such outdoors networks. Increased range of handheld devices is achieved through AP transmit and receive diversity mechanisms. Transmit diversity of APs, including STBC and transmit Beamforming, improves the downlink range performance. Receive diversity of APs, including MRC, reciprocate the transmit diversity and thus maintain the range for both the uplink and the downlink directions.
Improvements in Voice Performance
The handheld devices operating in the enterprise, campus and municipal networks enjoy improvements in VoIP performance and efficiency through protocols like, block ACK and frame aggregation. The required WMM part of the certification ensures that voice streams get priority over other classes of traffic and thus further enhances the voice service.
Home Environment
With its increased coverage and throughput, 802.11n enables HD video and audio-visual (AV) multimedia applications in the home environment. Increased throughput and WMM capabilities enable more reliable transport of simultaneous voice and multimedia sessions.WMM certification helps ensure high quality of Wi-Fi calls, while the increased throughput and coverage of 802.11n provides sufficient bandwidth to transport multiple video streams to Wi-Fi enabled set-top boxes or TV sets around the house.
The high bandwidth and QoS of Wi-Fi CERTIFIED 802.11n draft 2.0 systems helps ensure that an internet connection can be reliably shared by the increasing number and type of Wi-Fi enabled devices in the home without degradation of service. Higher data rates of 802.11n also increase the throughput capacity of overlapping Wi-Fi networks.The increased range of 802.11n provides coverage of the entire house, reaching farther than the legacy technology and reducing “dead spots” or low-rate areas in the home. Even single-antenna mobile devices, such as Wi-Fi phones, will enjoy the benefits of increased range and throughput of Wi-Fi CERTIFIED 802.11n by virtue of the transmit diversity capabilities, such as Space Time Block Coding (STBC), Cyclic Shift Diversity (CSD) and Transmit Beamforming.Most network transactions, including voice and data services, will benefit significantly from the 802.11n frame aggregation technology. Printing files from PCs to printers, transferring files between PCs and network drives and sharing files between PCs, laptops and other devices on the network becomes more efficient with 802.11n thanks to frame aggregation.
Enterprise Environment
802.11n is enterprise-grade technology that will provide IT managers with nearly the same reliable service they have come to expect from their Ethernet networks. Mission-critical enterprise applications, such as Customer Relationship Management (CRM) and Enterprise Resource Planning (ERP) access, collaboration tools, voice and video conferencing, will all benefit from the increased throughput and range of 802.11n.The new efficiencies and enhancements of 802.11n on the MAC and PHY layers, combined with the WMM QoS capabilities, serve to improve the quality of VoIP and to increase the number of simultaneous calls on the airlink. Physical layer transmission enhancements of 802.11n, such as Space Time Block Coding (STBC), improve reception even for single receiver Wi-Fi phones by virtue of transmitting multiple copies of a data stream via multiple antennas. Multiple versions of the signal reaching the phone are received and processed with specialized decoding techniques to provide redundancy of signaling and optimize reception.Of significant benefit to the Enterprise is lower density of APs, made possible by the improved efficiencies in the MAC, enhancements in the PHY operation and longer reach. Due to faster physical layer transmissions, stations get on and off the air faster, improving the airlink efficiency. The MAC layer mechanisms such as block ACK and frame aggregation also improve the airlink efficiency by reducing the overhead of packet headers, inter-frame gaps and ACK transmissions.Legacy stations in the 802.11n network can benefit from better coverage provided by the 802.11n APs’ CSD and MRC techniques and they can also gain increased access to the airlink as the new 802.11n devices get on and off the air faster.
Campus and Municipal Networks
Campus and municipal networks typically operate in challenging environments where range is the biggest issue. 802.11n is well-equipped to improve the operating range even for single-antenna handheld devices used in such outdoors networks. Increased range of handheld devices is achieved through AP transmit and receive diversity mechanisms. Transmit diversity of APs, including STBC and transmit Beamforming, improves the downlink range performance. Receive diversity of APs, including MRC, reciprocate the transmit diversity and thus maintain the range for both the uplink and the downlink directions.
Improvements in Voice Performance
The handheld devices operating in the enterprise, campus and municipal networks enjoy improvements in VoIP performance and efficiency through protocols like, block ACK and frame aggregation. The required WMM part of the certification ensures that voice streams get priority over other classes of traffic and thus further enhances the voice service.
The future of 802.11－11n
The new generation of IEEE 802.11n-based Wi-Fi standards is expected to pick up significant market momentum in 2008. Draft 2.0 of the 802.11n amendment to the standard is now widely considered stable, with only minor changes from draft 1.0.Tests conducted by vendors and independent test labs show that draft 802.11n products reach up to twice as far and are as much as five times as fast as legacy 802.11a/b/g technology. The currently available draft 802.11n technology can comfortably cover a typical house with sufficient bandwidth to support video, gaming, data and voice applications.
The developing IEEE 802.11n standard is based on MIMO (multiple-input multiple-output) air interface technology. MIMO is a significant innovation and a technology that is being adapted for use by several non-802.11 wireless data communications standards, including 4G cellular. MIMO employs a technique called spatial multiplexing to transport two or more data streams simultaneously in the same frequency channel. Spatial multiplexing is central to 802.11n and has the potential of doubling the throughput of a wireless channel when two spatial streams are transmitted. Generating multiple spatial streams requires multiple transmitters, multiple receivers and distinct, uncorrelated paths for each stream through the medium. Multiple paths can be achieved using antenna polarization or multipath in the channel.
The developing IEEE 802.11n standard is based on MIMO (multiple-input multiple-output) air interface technology. MIMO is a significant innovation and a technology that is being adapted for use by several non-802.11 wireless data communications standards, including 4G cellular. MIMO employs a technique called spatial multiplexing to transport two or more data streams simultaneously in the same frequency channel. Spatial multiplexing is central to 802.11n and has the potential of doubling the throughput of a wireless channel when two spatial streams are transmitted. Generating multiple spatial streams requires multiple transmitters, multiple receivers and distinct, uncorrelated paths for each stream through the medium. Multiple paths can be achieved using antenna polarization or multipath in the channel.
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