Research On Multi-channel Scheduling Algorithms Based On Non-orthogonal Channel In Wireless Sensor Networks

Wireless sensor network is a kind of multi-hops and self-organizing wireless network, deployed in the monitoring area by a large number of sensors on the wireless communication mode. The original wireless sensor network is to use a single channel to communicate, but with the increase of the network scale and the improvement of the real-time requirements, the constraint of the single channel communication becomes more and more obvious. Therefore, the domestic and foreign scholars have devoted themselves into the research on multichannel communication, having put forward lots of classical channel assignment algorithms. However, the existing channel assignment algorithms based on 16 orthogonal channels of IEEE 802.15.4 standard in ISM band, in which the 16 orthogonal channels are available, without considering the other applications' impact on these channels.Firstly, through a large number of experiments, this paper verifies that only four channels can meet the reliability requirements in industrial scene among the 16 channels of IEEE 802.15.4 standard ISM band. However, the four channels cannot meet the users' requirements of the real-time data transmission in industrial environment. Then, this paper introduces the concept of non-orthogonal channel, and verifies the feasibility of the non-orthogonal channel through a lot of experiments, and gives the condition of the feasibility. Finally, through the experiment, this paper verifies the non-orthogonal channel in band is given, there are more available channels than the existing orthogonal channel.On the basis of non-orthogonal channel, in this paper, the lack of TASA algorithm is analyzed and improved in the wireless sensor network converge scenarios, this paper proposes a multi-channel scheduling algorithm, MSNOC, based on the non-orthogonal channel. On the basis of introducing the importance of node and the non-orthogonal channels, MSNOC, by assigning slot and channel without mutual interference to the links of the network, ensures prior transmission of data packets of the node with high importance, and realizes the data collection with no interference, high reliability and high instantaneity. Finally, through simulation we compare the MSNOC algorithm on the two big aspects, the real-time performance and reliability, with the existing algorithm TASA. The analysis of simulation results shows that, the proposed algorithm MSNOC, compared with existing TASA algorithm, ensures the reliability of the data, at the same time, greatly reduces the time of data collection, especially greatly reduces the time of data packet collection for important nodes.