WLAN technology has been widely used in our work and life and is increasing its importance every day. WLAN can provide users with unprecedented flexibility, convenience and significantly improve work efficiency. In wireless monitoring, industrial control, mining, security, medical and other industries, the embedded wireless system mainly adopts a non-operating system environment, which is composed of "CPU + wireless data transmission module" and can realize short-range low-bandwidth wireless communication .
In order to solve the problems encountered by engineers in the application and development of WLAN without an operating system environment, experts in this issue invited Wang Yifeng, technical director of Beijing Zhongdian Huada Electronic Design Co., Ltd., and Gao Qiang, senior manager of industrial promotion of WAPI industry alliance, as guests. Share their experience in design.
Netizen Hongdaozi: Compared with other 2.4G wireless transmission module products, what are the advantages of Nos-Wlan modules?
The Nos-Wlan module is designed to deal with the differences between the platform and the compilation environment. It can achieve cross-platform and operating system. The biggest advantage compared to other wireless transmission modules is that it can greatly accelerate the wireless transmission module on the client system. Porting can greatly reduce the development cycle.
Netizen leovsdaisy: Does no-os mean that the module is very portable?
As long as there is a stable USB HOST driver on the client's small system, the Nos-Wlan module can be easily and quickly transplanted. When the client system performs data transmission, it only needs to package the data packet into an 802.3 format data frame and submit it to the Nos-Wlan module. When receiving, the Nos-Wlan module packages the client protocol frame data into 802.3 frames and submits them to the client system for processing.
Netizen Xiao Deng Xiaobian: Nos-Wlan module transplantation technology in the absence of operating system environment mainly overcomes those technical difficulties. How is it well transplanted? What challenges will it face to further improve? In the next five years What is the application prospect of WLAN?
The design of Nos-Wlan module mainly deals with the factors affecting the portability of the module, such as the size of the platform, the length of the platform machine word, and the resources of the platform. The code is written in ANSI C. The use of these technologies makes Nos -The Wlan module can be independent of any platform environment; the biggest difficulty of module transplantation is the cooperation with the USB HOST driver. The internal implementation of the module adopts a non-blocking method, so the customer USB HOST driver is required for batch transmission of frames and control frames. The transmission interface function uses the non-blocking method as much as possible. In some embedded platforms, the non-mainstream USB HOST is used. The driver is often designed for applications such as U disk. The transmission and reception are synchronized and can only be carried out at the same time. A kind of frame transmission, and the application characteristic of network card is that the data reception time and length are indefinite. In order to improve the throughput of network card, it is often necessary to realize the asynchronous transmission and reception of USB batch transmission frames; the further improvement of the module mainly faces the problem Lies in how to better cooperate with the underlying USB HOST driver, this part is often in the existing module Most of the transplantation time is occupied in the transplantation process; at present, in wireless monitoring, industrial control, video transmission and other industry applications, embedded wireless systems mainly use a non-operating system environment represented by the NORDIC solution, which consists of "CPU + "Wireless data transmission module" structure, can achieve short-range low-bandwidth wireless communication, in order to meet this demand we launched Nos-Wlan module. Therefore, the future application is still mainly in the fields of industrial applications, security monitoring, etc., to meet the needs of upgrading wireless functions of existing products in these fields.
Netizen Baobaofan: Does this refer to the conversion of the transmission process, or does it mean something else?
Nos-Wlan software module is a relatively independent and interdependent software module in the customer system. Relatively independent means that the protocol processing within the module does not depend on the customer system, and interdependence means that the module needs to provide USB through the customer system The driver communicates with the hardware of the network card, and processes user data frames through the user protocol stack (such as TCP / IP) interface provided by the client system. "Transplantation" mainly refers to the transplantation of the USB driver interface part and the user protocol stack interface part. The implementation of the transplantation mainly refers to the implementation of the relevant interface functions required by the Nos-Wlan module to be realized by the customer, mainly to realize the two standard protocol frames of USB (batch transfer frame) (BulkIn, BulkOut), control frame) transmission, call the Nos-Wlan data frame sending interface function to send the user protocol stack frame and implement the Nos-Wlan module data reception callback function so that the Nos-Wlan module submits the received data to the user protocol stack for processing Data Frame.
Netizen Fengyun Mike: Can you ask experts to define "Nos-Wlan"?
"Nos-Wlan" is a new product launched by Beijing Zhongdian Huada Electronic Design Co., Ltd. This product provides a Wi-Fi driver software that is not based on any operating system and can be easily integrated into any operating system. (Such as Linux, Ucos, Ecos, Vxworks and other embedded operating systems) or no operating system (such as single-chip environment, etc.) running on the system platform to accelerate the upgrade of the wireless functions of existing products. The software is 100% implemented using ANSI C, and 802.11 Protocol processing and related encryption (WEP, WPA / WPA2 PSK, etc.) are packaged in the form of C library functions.
Netizen mask: Recently, I seem to see a lot of news about Wi-Fi. There is really not much domestic information. Can you please tell us about the recent trends of the WAPI Alliance?
The WAPI Industry Alliance has been promoting the internationalization of WAPI standards and the promotion of WAPI in industrial applications. The WAPI products of BGI have always supported WAPI standards and have been well promoted in the fields of security, surveillance, wireless POS, etc. As always, it will cooperate with BGI to promote its WAPI products and promote the application of WAPI.
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