| Wireless networked control system (WNCS) has many advantages such as high integration level of information, strong flexibility and low wiring and installation cost. However, due to the presence of basic issues in WNCS, such as network-induced delay and packet loss, dynamic link characteristics, time-varying channel gain and interference of limited network bandwidth, analysis and design of WNCS become more complex. In recent years, WNCS stability analysis, control strategy, and network optimization have become a focus of research.It is a key problem in NCS to provide a stationary environment in networked control system by improving the service quality of the network, and decreasing the packet loss. In the net protocol, scheduling strategy directly affects the effectiveness and the realtime of the wireless network, thus it affects the performance of the wireless networked control system. The paper introduces a scheduling strategy with dynamic priority in order to ensure that the network nodes can be fair into the network, and reduce the probability of packet lost while cost a little more time-delays, therefore, the protocol can provide efficient quality of service for the wireless networked control system.IEEE 802.15.4 which is used for low power and low transmission rate situation is a wireless network protocol made by IEEE. This protocol is very flexible and can be adapt to the network requirements for different occasions through set the parameters of MAC layer. However, when the network is busy, there are many packets lost in the wireless network based on the native IEEE 802.15.4. In this paper, we use IEEE 802.15.4 protocol as research object, and do some research concerning network-induced delay and data packets dropout problem in IEEE 802.15.4. The simulation and experiment results indicate that the protocol reduces the probability of packet lost, and is better to meet the wireless networked control system for network service requirements. |
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