Parent node discovery time reduction algorithm for low-power wireless sensor networks

摘要

In multi-hop wireless sensor networks (WSNs) consisting of intermittent operating nodes, increases the processing time in the parent node discovery phase is an important issue because in the conventional parent node discovery method, the joining node chooses a parent node from among all its neighboring nodes. In the proposed scheme, if a neighboring node satisfies the parent selection condition (e.g. having a minimum packet loss rate) for the joining node, it informs the joining node before the other nodes that do not satisfy the condition, allowing the joining node to choose it as a parent node first. In the scheme, neighboring nodes change the timing with which they reply in an autonomous distributed manner by a parameter defined in the scheme. To determine the relationship between the parameter and the processing time spent in the parent node discovery phase, we measured the processing time with wireless units, also in the environment where the hidden node problem happens. The results show that the processing time increases due to a collision caused by the hidden node problem when the parameter is quite small. The processing time also increases due to delay of first reply from a neighboring node when the parameter is quite large. However, the processing time reduces in the middle range of the parameter and the range is wide. Therefore, the proposed scheme can be applied to WSNs such that the number of the hidden nodes and the neighboring nodes cannot be determined precisely.