| With the rapid development of the Internet of Things(Io T),the types of "things" in the Io T are becoming more and more diverse and complex,and it is required to design the Io T gateway which can be adapt to the hardware and software requirements of complex environments.However,in face of complex application environment,the existing gateway design methods often bring about high power consumption and low throughput.Thus,how to avoid unnecessary power consumption and improve the throughput of Io T system is of great significance in the design of Io T gateway.Recently,an embedded heterogeneous network fusion gateway has been attracted more attention by many researchers,which can provide an effective way to solve the above problems.In addition,because of the complexity of embedded heterogeneous network fusion gateway design,few existing design methods consider how to be compatible with multiple communication protocols.Motivated by the earlier discussion,this paper proposes an embedded heterogeneous network fusion gateway design method,which can be compatible with multiple communication protocols and possess the property of low power consumption and high throughput.At the meanwhile,the effectiveness of the developed design method is verified by the experiment.The main research and development work of this article is as follows:First,the overall design of embedded heterogeneous network fusion gateway which supports multiple communication is implemented.This design scheme supports common communication methods such as Wi Fi,BLE,and Zig Bee,and it can be adapted to popular short-range wireless communication terminal devices such as BLE and Zig Bee,meanwhile reliable,stable,and energy-efficient communication is ensured on the premise of high throughput.In order to solve the problem of data interaction between heterogeneous networks,this article provides a Post protocol that can be used for multi-protocol adaptation to achieve reliable communication between the link layer or the transport layer of several heterogeneous networks under the POST communication protocol.In order to ensure thereliable and safe data transmission of the gateway,the gateway uses symmetric encryption(AES)technology for the transmitted data.By periodically setting and updating the data decryption key,the data is encrypted and decrypted to achieve reliable and safe communication between the two parties;In order to improve the data transmission speed,this paper designs a double-buffered "ping-pong" storage,establishes a two-level "ping-pong" buffer data queue in SDRAM,and improves the gateway data transmission throughput;In order to reduce the power consumption,this paper designs a low-power sleep mode,which is embedded in the idle task of the gateway,so that the gateway enters a low-power state when it is not working.Secondly,the development of the gateway hardware is completed,we select the STMicroelectronics' STM32F429 chip as the main control chip.Then based on the main chip,the SDRAM circuit,Wi Fi,Zig Bee,BLE module circuit and other circuits are designed to achieve the various hardware of the gateway features.Thirdly,the development of the gateway software is completed,including the transplantation of tool software such as the Free RTOS real-time operating system,and the design of each task of the gateway management program.In the design of the gateway management program,USB tasks,data reception tasks,data copy tasks,gateway data processing tasks,login and heartbeat tasks,data distribution tasks,BLE tasks,Zig Bee tasks,watchdog tasks are finished.Finally,the effectiveness of the designed heterogeneous network convergence gateway is verified.The test results show that the heterogeneous network fusion gateway has reliable and stable performance,can achieve reliable communication between link layers or transmission layers across several heterogeneous networks,and achieves the low power consumption on the premise of ensuring that the transmission speed and transmission stability remain unchanged. |
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