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The nature of packet loss of wireless links at 2.4G band was analyzed and a wireless link quality prediction algorithm for wireless sensor networks was proposed. In the proposal, RSSI (Received Signal Strength Indicator) and LQI (Link Quality Indicator) were utilized to produce a couple of metrics of wireless link quality, named S_m and delta respectively, and their distributions were studied. By using SAX (Symbol Aggregation approximately) method, the LQIs were mapped into different symbols, and summarized the preceding symbols of link quality deterioration in collection of patterns. Then the distance of a sample to patterns was used to determine the probability the link deterioration, so that the link quality of the next period was predicted. The proposed method is simple, so it is easy to implement in wireless sensor network. Finally, the experiment using practical link data showed that the proposed method can predict more than 80 percent of the link deteriorations

Abstract-According to EGTS proposal, an adaptive channel hopping algorithm that can be used in wireless mesh sensor networks was is designed in this paper. The nodes select proper channels independently and use them to communicate with their neighbors. Once a pair of nodes find their current channel has been deteriorated, they abandoned the current channel and enable the reserved channel, so that the reliability of the network is improved. The algorithm is compatible with the primitives and the frame structure of EGTS and makes use of multi-channels efficiently. The data structure and the procedure of the mechanism were described in detail and the feasibility and the efficiency was given by analysis and experiment. Finally, it is concluded that the algorithm is practicable when the density of network is less than 8 and the topology is relatively static.

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