Bias child node association avoidance mechanism for hierarchical routing protocol in 6LoWPAN

6LoWPAN enables IPv6 to be applied to wireless sensor network and enable end to end communication. One of the 6lopwan features is the capability of dynamic assignment of 16 bit short addresses. Using this feature a hierarchical routing protocol was designed. The designed hierarchical routing protocol focuses on the address allocation method and routing mechanism. However the routing protocol doesn´t address scenario where there is more than one potential parent node. If the child nodes attaches to the first responding parent when there is more than one potential parent than this could lead to bias or uneven distribution of child node. Bias association could impact the reliability and also shorten the life span of the network. To overcome this problem a mechanism which uses current number of child node of potential parent was suggested. This mechanism displayed weakness when the responding parent node is having different depth or energy level or same number of current child. This paper reviews current hierarchical routing, highlights the issues and suggests a mechanism which avoids a bias routing hierarchical tree set up by taking into account the potential parent node´s signal strength, depth and energy level.