Bluetooth system has defined piconet structure and how to connect several piconets into a scatternet is one of the main research issues. Currently, there are many scholars to study the scatternet formation and to propose their own methods. These methods include tree algorithm, ring algorithm, star algorithm, mesh algorithms and etc. In the paper, we propose Enhanced Bluetree and Layer Bluetree scatternet algorithm to improve the Bluetree performance. Based on the Bluetree design, Enhanced Bluetree uses leaf nodes to conduct a return connection mechanism. This mechanism can make Bluetree scatternet architecture from a tree structure into a mesh structure and thus improve the connectivity efficiency. In addition, Layer Bluetree conducts the return connection mechanism in the intermediate nodes to form the mesh architecture. Simulation results shows that Enhanced Bluetree achieve better network performance than Bluetree by reducing the average path length among nodes. On the other hand, Layer Bluetree reduces the network formation time than Enhanced Bluetree.
