| Wireless Sensor Networks (WSNs) have been popular for over decades with single channel transmission technology. With the increasing demands of different purpose, the quality of data transmission does face a dramastic dropping. The reasons of this problem lie in the following aspects. First of all, the fact that there are more than one WSNs in the same area leads to high nodes density and traffic jam in channels. On the other hand, WSNs use the same frequency band with Wifi in 2.4GHz. With the popularization of Wifi, this interference becomes worse. In order to solve this situation, multi-channel transmission theory and technology are developed.Multichannel transmission needs to arrange the channels rationally, to verify the effective-ness of multichannel assignment algorithms, software and hardware evaluation are the two main methods. Software evaluation is low-cost and easy to build, but the results are not very reliable. On the contrast, though hardware evaluation costs more and needs more efforts in designing and building, the results are guaranteed with the actual environments. So far, no experiment testbeds are designed especially for WSN channel assignment algorithms. The novelty and contributions are summarized as follows:1. Investigate and survey on the background and research status of assignment algorithms and evaluation methods in WSNs.2. A testbed especially designed for WSN channel assignment is built based on MICAz nodes. Users can configure the topology flexibly, test different algorithms, and monitor the real-time topology and results through the User Graphic Interface (GUI).3. Regret Matching based Channel Assignment Algorithm (RMCA) and Multi-frequency Me-dia access for WSN (MMSN) are tested by the experiments on the testbed mentioned above. RMCA outperforms in terms of both Valid Transmission Ratio (VTR) and Average Trans-mission Delay (ATD), which agrees with the simulation results. As a result, the effectiveness of the proposed hardware testbed is also guaranteed.4. After further research and analysis on the testbed results, an improved algorithm Coordinated Regret Matching based Channel Assignment (CRMCA) is proposed. Then CRMCA is tested on the testbed as well with the effectiveness verified.The conclusions and future work are depicted in the end of the dissertation. |
