Talking about the new technology of current wirele

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Talking about the current wireless broadband network new technology super G

Abstract: with the introduction of IEEE 802.11g wireless network standard, the implementation of WAPI Standard in China has been delayed. In view of the shortcomings of IEEE 802.11g standard in practical application, an enhanced wireless network technology and equipment based on IEEE 802.11g have appeared in front of Chinese people. This paper describes the technical overview, characteristics and performance of super G, and prospects the future of this technology

Keywords: bandwidth super G burst dynamic packet fast frame

1. Introduction

in recent years, with the rapid development of wireless communication technology, people's demand for bandwidth is growing. Even the IEEE 802.11g standard officially launched in early 2004 is far from the traditional wired Ethernet bandwidth. IEEE 802.11g is based on the 2.4G frequency band, and the theoretical bandwidth is 54mbit/s. Even in an ideal practical environment, the bandwidth can only reach half of the theoretical value, which is difficult to meet the needs of multimedia real-time services, IP (VoIP) and video on demand (VOD) services. In order to further expand the bandwidth, all manufacturers are developing and formulating next-generation standards and technologies

Atheros introduced super G technology in accordance with the current technical standards, which improved the network performance of IEEE 802.11g. Super G can provide amazing data throughput (theoretical value is 108mbit/s, actual value is 60mbit/s) for bandwidth requirements, and also enhance the coverage

2. Technical features

super g improves the transmission rate by enhancing the network performance characteristics. On the basis of maintaining the existing standards, the transmission speed of physical layer, data link layer and network layer can be greatly improved by improving the corresponding technologies. Super G has the characteristics of dynamic packet burst mechanism, hardware compression, fast frame and dynamic turbo dual band bundling. These characteristics can operate independently, providing greater network throughput for wireless transmission

2.1 dynamic packet burst mechanism

burst mechanism uses IEEE 802.1le quality of service (QoS) draft to automatically adjust data packets and transmission time to adapt to different connection speeds and protocols, enhance the performance and network processing capacity of the whole system with IEEE 802.11a, IEEE 802.11b and IEEE 802.11g access devices at the same time, and improve data throughput in the same or mixed environment. The burst mechanism is shown in Figure 1. IEEE 802.11 series protocols stipulate that in the process of standard transmission, there needs to be a certain time interval between adjacent data packets, which is called inter frame gap (DIFS). The burst mechanism is to cancel DIFS and send data packets as continuously as possible to improve data transmission. By sending multiple packets at a time, DIFS can be reduced and transmission efficiency can be improved. In the short frame gap (SIFs) of sending packets, the burst mechanism can automatically detect whether other nodes use wireless local area network (WLAN), which fully shortens the sending time and improves the data throughput. Super G technology supports burst transmission mechanism in timely acceleration, and can receive all burst transmissions. If a device that confirms the failure of the burst mechanism is connected, super G technology will return to the non burst mode (i.e. basic link mode)

the dynamic packet mechanism in super G technology is based on the IEEE 802.11e standard draft and is an acceleration means to support the enhancement of distributed coordination function (EDCF) and wireless multimedia extension (WME) QoS. This performance enables more network users to enjoy the maximization of network throughput. For example, dynamic mechanism is particularly important in multi node network system. If there are at least two nodes near an access point (AP) or remotely, the remote node will transmit data packets at a low speed, which consumes more transmission time than the nearby node, while the nearby node, which should be faster, loses the opportunity to connect with the AP due to the lack of space transmission time. The dynamic mechanism limits the transmission time of each frame in super G burst frame technology. Because many materials in engineering have no obvious yield point, the time of transmitting each frame is shortened, and the nearby nodes can burst more frames than the remote nodes. On the basis of consuming less transmission time, more frame data is transmitted. The data packet transmission in the whole network is not fixed, and the fast devices get more burst frames in the network than the slow devices. Dynamic burst packet mechanism combines dynamic mechanism and burst mechanism. The two mechanisms interact and cooperate with each other to achieve their unique functions. The biggest advantage of super G dynamic burst mechanism is to enhance the performance of the whole system and network processing capacity

2.2 hardware compression

the principle of hardware compression is to embed a compression mechanism in all hardware using super G technology, and carry out hardware compression and decompression without affecting any data transmission and frames, so as to greatly improve the throughput of data transmission

like the popular compression software winzip, super G uses hardware compression to implement the standard Lempel Ziv standard algorithm. Carry out hardware compression before data transmission; After the data arrives at the wireless receiver, decompress and restore it. The compressed data becomes smaller, reducing the transmission time of data, so as to release more transmission time and meet the transmission requirements of more wireless devices

2.3 fast frame

fast frame places more than one data packet in the data frame of a wireless LAN. The function of fast frame is to assemble multiple original frames into large frames, increase the length of transmitted frames, reduce the loss of inter frame interval, and achieve the purpose of improving the efficiency of continuous transmission. The fast frame mechanism is shown in Figure 2. The classic data frame is connected to Ethernet through wireless bridge, which is usually limited to 1500byte at most. The improved fast frame can be superimposed on the burst mechanism by using the change control algorithm to determine the actual packet structure according to the network situation. Once the negotiation is completed through the special AP node link, both parties can send fast frame packets of no more than 3000byte to each other. Most burst devices do not provide fast frame services, so super G has more advantages in this regard, which largely depends on the competitiveness of the raw materials used

fast frame technology is also supported by IEEE 802.11e draft. Like burst mechanism, maybe not all other hardware supports fast frames, but it is a specific technology based on IEEE 802.11e draft. Fast frames only work on the existing periodic parameters of the basic link, and do not involve frame spacing, frame period or connection window parameters. The most prominent advantage of this technology is that it can better calibrate more networks than a single burst mechanism

2.4 dynamic turbo dual band bundling

dynamic turbo dual band bundling mode uses two wireless channels. The bound dual band looks like receiving and sending in a separate channel, which can not only obtain double data rate, but also increase the effective coverage of the network. Just as the 1o/100/1000m Ethernet backbone increases the bandwidth by binding multiple physical links, using multiple wireless channels to double the data transmission rate is a significant advantage of dual band binding, which can increase the network coverage at the same time. Generally, the farther the user is from the wireless router, the lower the data rate until the user within a specific distance no longer has enough bandwidth. For example, the connection speed of 36mbit/s can only be achieved at a place much closer than the connection point of 18mbit/s. With binding technology, the data transmission rate within any specific distance is doubled. For example, where there was only 18mbit/s connection, 36mbit/s transmission bandwidth can now be provided; Where 6mbit/s is connected, 12mbit/s can be connected. Super G can provide multiple wireless channels for users to choose at the same time, which can not only double the single channel transmission, but also increase the effective coverage of the network

super G can preset dynamic turbo according to network needs and different environmental conditions. When connecting users need continuous and high-throughput bandwidth, AP will switch to dynamic high-performance mode. The system will automatically return to the normal mode periodically to enable other users to access the network. If other users are connected to the AP, it will not enter the high-performance mode. The AP will automatically reset the multi-channel and single channel modes to eliminate all interference for users

under standard service conditions, dynamic turbo has little impact on external wireless networks or devices. In addition, if the network detects that an adjacent channel attempts to access the running dynamic turbo mode, the AP will automatically switch to the single channel mode, while maintaining the other characteristics of super G, so that the operation of the adjacent network will not be affected

dynamic turbo can only have devices with larger bandwidth when authorized to run. In the 2.4GHz band, there is a turbo channel at the 2437mhz carrier center frequency. For the 5GHz band, there are three turbo channels in the low band of the band; At the high end of the band, there are also carrier center frequencies (5756mhz and 5805mhz) of two turbo channels

3. Conclusion

with the rapid development of WLAN bandwidth application, oxygen cutting and other methods can be used. Once the existing standards are introduced, they obviously can not meet the actual needs. Super G can provide tcp/ip throughput of more than 60mbit/s on IEEE 802.11b/g/a (super Ag) devices, provide the best bandwidth solution for the same AP under more complex access conditions, and be downward compatible with IEEE 802.11b/g/a (super Ag) devices, At the same time, it also optimizes the network structure more widely

in addition, super G enhanced technology not only conforms to the current IEEE and Wi Fi joint protocols, but also makes preparations for the expansion of the future IEEE 802.11n standard

super g in dual band operation, on the surface, it occupies two communication channels as a dual band turbo channel, but in fact it misappropriates another idle channel for its own use, and the AP based on super G technology also provides only one unit of Turbo channel (super Ag can provide 5 units of Turbo channel because it is on 5g carrier). However, its current limitation is that if all 11 channels in IEEE 802.11b/g are occupied by devices, or all access devices are in the busy section, the four features of super G will not be brought into full play. Under these conditions, its high bandwidth becomes sudden and temporary

super G is only an enhanced technology under the current standard, and it is only a technical supplement and improvement based on IEEE 802.11g standard. Its high bandwidth can be achieved under specific conditions. To truly meet the demand for bandwidth, we can only look forward to the next generation of wireless network standard IEEE 802.11n


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