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This paper proposed an energy-aware routing method, P-AODV. Based on the AODV routing protocol, this study designed a passive power control (PPC) algorithm to enhance energy efficiency. The proposed method includes signal detection and power setting phases. During the signal detection phase, the source node broadcasts the route request packets (RREQ) and the downstream intermediate node calculates the optimum power level at the upstream intermediate node according to the received signal strength indicator (RSSI) after receiving the RREQ. During the power set phase, the destination node returns the RREQ packet to notify the power level of the upstream nodes to the source node. After that, all nodes from the source node to the destination node engaged in transmission will transmit data in a coordinated power level. As indicated by the computer simulation results, P-AODV could have 30% higher energy efficiency than traditional AODV. This PPC algorithm could also be used in wireless mesh networks (WMNs).

Blueweb is a self-organizing Bluetooth-based multihop network equipped with a scatternet formation algorithm and a hybrid routing protocol. The routing protocol combines the reactive method globally and the proactive method locally to discover the optimal path for packet transmission. In Blueweb, the route master maintains the global topology information and each master maintains its own N-tier routing information. In this paper, a tier number decision algorithm is used in Blueweb to determine the optimal number of tiers for all the other masters. Our computer simulation results show that this algorithm can efficiently improve the routing performance and reduce the routing maintenance cost for Blueweb routing protocol.

This paper proposes a layer-ring formation with a self-routing protocol, which contains two stages in forming a scatter net. In the first stage, all nodes randomly enter into an inquiry or inquiry scan state with a prior probability. As the winner, the inquiry node connects with the inquiry scan node, and collects the hopping information of the losers. Then, these winners repeat the first stage and collect the losers' information until the last winner as a coordinator is generated. In the second stage, the coordinator uses the collected topology information to compute the number of layers, as well as the role of each node, in accordance with a predefined formula. The coordinator then notifies all master nodes, and their corresponding Pico net nodes, which connect to each other via dedicated bridges until the layer-ring scatter net is formed. Moreover, a self-routing protocol is designed to efficiently deliver the packets over the layer-ring scatter net. Computer simulations include the scatter net performance of the packet delivery ratio, the packet delay and the throughput, in order to demonstrate the routing efficiency of the layer-ring method. As a result, the joint layer-ring method with the self-routing protocol achieves better scatter net performance than the conventional multi-ring method.

Blue web is a self-organizing Bluetooth-based multihop network equipped with a scatter net formation algorithm and a hybrid routing protocol. Blue web uses a designated root node to initiate scatter net formation and two mechanisms are introduced. One is the role exchange mechanism in which only slave nodes serve as the role of relay through the whole scatter net. The other one is the return connection mechanism in which we convert the scatter net from a tree-shaped to a web-shaped topology. In this paper, a variant-hop algorithm in forming Bluetooth sensor scatter net is proposed. Based on the design of Blue web, this algorithm is a tier-based method to determine new roots and each new root spontaneously generates their individual web-shaped subnets. The heuristic method describes the variant-hop algorithms. With a constant k, a counter variable v, and return variable r as parameters, the variant-hop algorithm generates appropriate roots locally and evenly configures the subnet size. Computer simulation shows that this method achieves good network scalability and generates an efficient scatter net configuration for Bluetooth-based multihop sensor networks.