Internet of Things II: Sensor wireless network

Business model

Here's a look at sensor wireless networks. The first is the business model diagram:

The mode diagram of the sensor's usage scene is composed of five parts, namely sensor, monitoring area, aggregation point, Network (Internet, etc.), data expansion layer, and expansion layer, which is a very imaginative part, which can be data analysis, data presentation, data storage, etc.

For the sensor, there are three parts, namely: sensing part, Central processing part (processor, memory, application calculation) and network part (wireless network)

The technical component diagram is as follows:

Top is the industry, the common two is the management and security layer, in the industry is the application layer, including the industry is just as well as the requirements of customers; Network support technology This next we will do a detailed introduction, the following is the basic platform facilities, based on supporting technology facilities. In fact, the core of the Internet of Things is network technology, which technology transmits data to the destination. The essence of the network is to collect/receive, transmit and analyze and process the data, the analysis and processing is the traditional business system, the acquisition is related to the hardware technology, and the transmission is dependent on the network technology.

Below is a technical architecture diagram of the components supporting the technology:

The application layer is actually the application of the component diagram, which is responsible for the business logic implementation;

Synchronous clock means that if the network layer chooses the time-sharing protocol, it is necessary to keep the clocks of each node consistent;

The transport layer is used to guarantee the transmission quality; The familiar three-time handshake TCP protocol is a member of the Transport Layer protocol cluster, and also includes the equilibrium traffic (the throughput between different network segments is inconsistent), at this level, the transport layer is also responsible for the role of matching;

The network layer is actually responsible for routing, the following we detail the routing protocol and mode, routing protocol is to ensure that the information reached the destination;

The Protocol of the network layer is mainly the routing protocol, there are three kinds of routing protocols: The first is broadcast type, this is the same as the spread of information in the circle of friends, everyone will (can) forward messages to non-communicators to achieve proliferation, in the process of diffusion, only the real information stakeholders will pay attention to the message; The second way is coordinate Here first a tree, each tree has its own coordinates, and then send the time from the leaf node will be sent, this way to a large extent reduce the number of cross-sending, the third is the cluster, that is, the node in accordance with the algorithm to select a cluster head to lead the cluster members, the advantage is that only the cluster head to stay awake State, Members are dormant for most of the time, and when the message needs to be sent, and the coordinates are compared, they are forwarded from the leaf node to the superior.

Next is the data link layer, this layer is mainly to the data packet frame processing (in the Transport layer information is encapsulated as a message, the network layer is sealed as a packet, to the link layer to continue to seal MAC information and assemble the frame for transmission over the network), as well as to check the frame;

There is a protocol that we often use in the link layer is the MAC protocol, the MAC address we talked about is actually for Mac protocol, MAC protocol has two major categories, namely, competition and time-sharing nature, competitive refers to the network resources constantly rotation to see if (channel) resources are idle, If the information is sent while Idle, the time-sharing property is based on the algorithm, allocated to each Mac fixed point, only in the time-point range of the device to use network resources to send data, the former is very resource-intensive (because of the need to constantly rotation), the latter is inefficient, because of timely network resources idle, network resources are not available for devices that do not have time-to-point, but the latter is undoubtedly more pro-gaze in the case of sensors that require high power.

The physical layer is responsible for sending data frames to the network.

As a wireless sensor network (Wireless sensor networks, WSN), a little technical considerations are important: the first is to be sure to save power, because the sensor is relatively small, but also need to have a source of the way to transmit data, so the longer the support time network availability is greater;

Internet of Things II: Sensor wireless network