1. Technical background
Wireless synchronous data transmission technology refers to obtaining trigger responses and making intelligent decisions based on collaborative sensing of changes in the target scene state. It is one of the key supporting technologies of the Edge Collaborative Sensing (EICS) technology, the core technology of Blue AoSound. This technology mainly involves the wireless communication method and service mechanism and process between the network service node and the target device.
The Internet of Things and its related wireless communication technology are one of the important supporting technologies for the rapid development of intelligent technology, which has led to the rapid development of product innovations in various intelligent hardware devices and intelligent service systems for individuals, homes and different application industries. For different intelligent application scenarios, the IoT edge domain with dynamic information interaction characteristics, which is composed of edge service nodes and several surrounding target object devices (i.e., network client devices), is mainly aimed at solving wireless problems in the target object domain and perception control domain. The service mechanism and process issues of network communication and information interaction.
According to the wireless communication node topology and protocol architecture, based on the current short-range, low-power IoT wireless technology standards, the network topology of wireless multi-point communication between the network service node and the target device (i.e., the network client device) can be The transmission method boils down to several basic types: wireless directional broadcast, wireless multi-point connection and wireless Mesh network.
Different from the classic Internet and mobile communication networks, the target devices targeted by the IoT edge domain network and its service nodes do not only include computers and smartphones that support standard wireless network access, have strong resource capabilities, Strongly intelligent terminal devices that can install various application software also include mobile or distributed target devices with lower cost, ultra-low power consumption, and relatively weak resource capabilities (such as wearable devices, distributed sensors, peripherals execution equipment, etc.).
The wireless network communication method between network service nodes and target object devices between devices in the edge domain of the Internet of Things. In many cases, the stability and interoperability of the edge network are more important, without the need for large-volume broadband communications; in When a network service node needs to provide concurrent services to the target device as a client in a "one-to-many" or "many-to-many" manner, in addition to the interoperability issues of dynamic access to the network, it also needs to pursue hardware resources, power consumption and transient state. The balance between response efficiency, that is, one or more service node devices can simultaneously provide synchronous transient triggering and concurrent data transmission services for several target object devices or device groups in low-power standby states.
Multiple collaborative agent nodes with the same or interrelated device network attributes in the edge domain of the Internet of Things form a collaborative agent network system with several surrounding proxy nodes through collaborative distribution networks. The cooperative agent node is managed by the upper cooperative agent node or the network system host (referred to as the "system host"); the service node device can perform wireless scanning and detection on the wireless beacons sent by the target device in different channels or time slots. In an instant (a very short period of time), the state variable feedback of numerous surrounding target devices is monitored and collected; typically, wireless devices can obtain wireless beacons through wireless scanning and detection methods up to dozens to hundreds of times per second. However, since wireless scanning and detection requires a lot of power consumption and resources, the target device that is in a low-power standby state before establishing a wireless connection cannot obtain fast trigger response and concurrency control from the service node device in the same way.
In the existing technology, wireless directional broadcast has a simple topology, less wireless resource usage, high synchronization data transmission efficiency, fast trigger response, simple wireless protocol, and good interoperability, but it has obvious flaws: asymmetric data transmission direction. characteristics, low efficiency of asynchronous data transmission, low efficiency of data reception feedback monitoring and high power consumption of the wireless receiving end.
2.2 Blue Aosheng wireless synchronous data transmission technology has the following shortcomings in existing similar technologies:
Although wireless multi-point connection can transmit multi-point two-way wireless data, the wireless data transmission is stable, the asynchronous connection communication is convenient and the security is relatively high, it also has certain shortcomings: such as the long response time to establish a connection, and the environmental and resource factors are relatively high. Sensitive and occupying a large amount of wireless channel resources, especially when there are a large number of client devices, the stability of wireless multi-point connections tends to deteriorate, the wireless transmission distance is shortened, and the wireless transmission power consumption increases.
Although wireless Mesh networks are simple to install and configure, easy to set up quickly, have flexible wireless transmission paths, strong redundancy mechanisms and communication load balancing, and low wireless transmission power, they also have obvious flaws: such as poor wireless interoperability and poor wireless communication High latency and poor cross-coverage synergy between different wireless standards make low-power client devices unsuitable for relay nodes, and the balance between standby power consumption and trigger response time must be resolved.
Therefore, how to solve the device power consumption of the wireless synchronization data receiving end, the accuracy of the synchronization time and the stability of the synchronization matching in the synchronization matching state, the trigger response of the synchronization data transmission and the speed of receiving feedback, and the reception status of the synchronization synchronization data transmission. The monitoring of feedback monitoring and synchronization of data packet data retransmission have become technical issues that need to be solved urgently.
2. About Lanaosheng wireless synchronous data transmission technology
2.1 About the technical problems solved by Lanaosheng wireless synchronous data transmission technology
The technical problems to be solved by this technology are the detection and reception timeliness of concurrent data transmission for low-power wireless synchronization data receiving end device groups, the accuracy of synchronization time and the stability of synchronization matching in the synchronization matching state, The monitoring of the trigger response and reception feedback speed of synchronous data transmission and the monitoring of the reception status feedback of synchronous data transmission and the management issues of the synchronous data packet data retransmission process.
2.2 Problems with defects in similar competing technologies (→see above)
3.Technical solutions
3.1 Overview
The wireless master device uses a wireless directional broadcast in a specific wireless mode to send a synchronization sequence beacon containing a synchronization time identifier and a synchronization data packet to several wireless slave devices in the target device group; when the wireless slave device receives the wireless When the master device sends a synchronization time identifier, it establishes and maintains a synchronization matching state with the wireless master device according to the synchronization time identifier, and places the corresponding matching verification identifier into its device status beacon; the wireless slave device In the synchronization matching state with the wireless master device, the terminal device maintains wireless time slot synchronization within each synchronization time period, and performs synchronization time correction at least once within each synchronization validity period to maintain the synchronization matching state. ; The wireless slave device starts receiving the synchronization data packet within its synchronization detection reception time slot, receives the synchronization data packet within the synchronization validity period, and sends the status verification code of the current corresponding synchronization data packet reception Placed in the device status beacon; the wireless master device uses wireless scanning and detection to collect the status verification code contained in the device status beacon sent back by all wireless slave devices in the target device group , verify and monitor the reception status of the synchronization data packet by all wireless slave devices, and accordingly maintain or update the sending process of the synchronization sequence beacon according to the status monitoring information.
3.2 Main technical characteristics
1) The synchronization data packet is a data packet concurrently transmitted by the wireless master device to multiple wireless slave devices in a wireless time slot synchronization manner; the wireless time slot synchronization is a number of wireless slave devices in a synchronization matching state. Through the synchronization time correction, the synchronization detection time slot of itself and the synchronization transmission time slot of the wireless master device are kept in time slot matching in the time domain.
2) The synchronization time identifier is the identification information of the relative time characteristics of the wireless beacon sent by the wireless device this time within its synchronization time period; the synchronization time identifier includes one or a combination of the following relative time characteristics: 1) Synchronization An indication mark is used to mark a specific timing position within the synchronization time period Ts without directly specifying the characteristic parameters; 2) A synchronization offset mark is used to indicate a specific timing position within the synchronization time period Ts. Relative time offset, in one or more synchronization time periods, at least one synchronization beacon among the synchronization sequence beacons has a synchronization offset identifier.
3) The synchronization time correction is the calculation of the time offset correction performed by the wireless slave device on its own synchronization detection time slot within the synchronization time period according to the synchronization time identifier; after each execution of the synchronization time correction , based on the given default number of cycles N and/or the correction offset of this synchronization time correction, shield the synchronization time correction of the current N synchronization time periods.
4) The wireless slave device performs the synchronization time correction based on the time slot matching relationship, and performs offset correction calculation according to the time slot matching time offset in the synchronization time identifier; the time slot matching time offset It is the offset time of the synchronization beacon sent by the wireless master device this time and the time domain characteristic position (typically the starting position of the time slot) of its synchronization sending time slot; the time slot matching relationship refers to the wireless The time domain of the synchronization detection time slot of the slave device matches and aligns with the time domain of the synchronization transmission time slot of the wireless master device.
5) The synchronization validity period is the longest duration allowed after a synchronization time correction to maintain the synchronization matching state; the wireless slave device performs at least one synchronization time correction within each synchronization validity period to maintain the synchronization time correction. The synchronization matching state is specifically: whenever the synchronization time correction is performed according to the synchronization time identifier, a new synchronization validity period timing is started; when the synchronization validity period timing exceeds its allowed maximum value, the synchronization validity period timing is deemed to have been lost. Sync match status.
6) When the wireless master device, as a collaborative agent node, receives the device status beacon sent by the wireless slave device in a direct matching state, it superimposes the bit selection code corresponding to the group sequence code on the matching monitoring Among the multi-selection codes; the collaborative agent node compares the matching monitoring multi-selection code with the agent matching multi-selection code based on the set matching monitoring period. When the two are not equal, the collaborative agent node directly uses the matching monitoring multi-selection code. The code selection replaces updating the agent matching multi-selection code; the agent matching multi-selection code is formed by performing a bit selection superposition operation on the bit selection codes of the collaborative agent node and all wireless slave devices with which it currently establishes a direct matching state. A multiple choice code.
7) When the wireless slave device is in a synchronized matching state with the wireless master device serving as the collaborative agent node, collaborative matching agent switching is performed through synchronized matching switching; the synchronized matching switching includes synchronization phase time adjustment, and Establish the synchronization matching state with the new collaborative agent node; adjust the synchronization phase time according to the synchronization phase time difference between different collaborative agent nodes, so that the synchronization matching switching can be completed instantaneously; the synchronization phase time difference is one A pseudo-random value that can be derived based on the current synchronization time parameters and the co-agent parameters of different co-agent nodes that can be matched.
8) The synchronization matching state is a state in which the wireless slave device maintains effective wireless signal detection and data reception for a matching wireless slave device based on time synchronization; when the wireless slave device corrects based on synchronization time Afterwards, before there is a new synchronization time correction, the wireless mode parameters are periodically switched according to the synchronization timing corresponding to the given synchronization time parameter to automatically maintain a synchronization matching state with the wireless master device.
4.Technical effects
4.1 Technical issues solved
This technology uses the wireless slave device to establish a synchronization matching state with the wireless master device in the form of wireless time slot synchronization based on the received synchronization time mark; in this way, it solves the device power consumption problem of the wireless synchronization data receiving end and avoids the problem of wireless receiving end. When waiting for the reception of synchronization data packets, more time is required to be in the wireless detection state with high power consumption. In the synchronization matching state, the wireless slave device maintains wireless time slot synchronization based on the time slot matching relationship in each synchronization time period, and performs synchronization time correction at least once within the synchronization validity period; thus solving the problem of synchronization in the synchronization matching state To solve the problem of time accuracy and synchronization matching stability, by improving the detection time slot efficiency, the trigger reception response speed and success rate in low power consumption state can be improved. The wireless slave device initiates reception within the synchronization detection reception time slot, receives synchronization data packets in the form of synchronization time slot modulation, and places the status verification code of the current corresponding synchronization data packet reception into the device status beacon. ;This solves the problem of trigger response and feedback reception speed of synchronous data transmission, and improves the flexibility and compatibility of synchronous data transmission and execution feedback. The wireless master device uses wireless scanning and detection to collect the status verification codes sent back by all wireless slave devices, and uses a multi-select overlay comparison method to verify and monitor the reception status of synchronization data packets of all device members; thus solving the problem of synchronous data transmission Monitoring and retransmission of synchronized data packets for receiving status feedback monitoring, improving the efficiency of status feedback monitoring and verification algorithms, and reducing redundant sending of invalid data from the main end.