TLDBR: Traffic Load Distribution based Routing Algorithm for Wireless Body Area Networks

Abstract

A Wireless Body Area Network (WBAN) is a network that consists of sensor nodes placed on or in the human body. A WBAN consists of a coordinator node and one or more sensor/actuator nodes. In a WBAN routes must be constructed in order for sensor nodes to propagate information to the coordinator. Due to differing operating conditions than standard Wireless Sensor Networks (WSNs) the existing WSN routing schemes are not applicable for a WBAN. Most studies for WSNs only consider homogeneous nodes that have the same energy capacity, functionality, and computational power. On the other hand, WBANs are often made of heterogeneous nodes specifically designed for a given application. The existing WBAN routing scheme, EAR, is inefficient because it concentrates energy consumption on certain nodes, this thesis presents an alternative routing scheme called Traffic Load Distribution based Routing Algorithm (TLDBR) which balances the energy load across the network. EAR reduces the lifetime of a network by concentrating the energy consumption at certain nodes. This increased power drain on specific nodes causes these nodes to fail earlier than other nodes in the network. When one of these nodes fails it also severs the link to the CN for all nodes that are routed through it. TLDBR balances power consumption by classifying nodes according to their characteristics, including energy, traffic generation rate and message priority and by finding paths that have balanced energy consumption. The distribution of traffic load is an important challenge in a network consisting of heterogeneous nodes because the nodes each generate data at a different data rate. In EAR nodes that send a heavy traffic load to the sink, as well as nodes near the coordinator that must forward a high level of traffic which will drain their battery much earlier than in the scheme proposed here. Also, in the proposed scheme, control message overhead is reduced by using the minimum number of control messages unlike, the existing schemes which using periodic message flooding. Simulation results shows that the protocol presented in this thesis outperforms the previous routing schemes in terms of both node failure rate and network lifetime.

Wireless Body Area Network (WBAN)는 사람 몸 주변이나 몸 속, 피부에 부착되는 노드들로 이루어진 네트워크를 말한다. WBAN은 네트워크 코디네이터와 센서 노드들로 구성되는데 통신이 되기 위해서는 노드들 간의 경로를 설정해 주는 것이 필요하다. WBAN에서 이루고 있는 노드들의 특징은 기존의 Wireless Sensor Networks (WSNs)에서의 센서의 특징과 상이하므로 기존의 WSNs를 위한 라우팅 알고리즘은 WBAN에서 적용이 적합하지 않다. 본 논문에서는 WBANs에서의 노드들의 특성을 파악하고 노드들의 에너지를 절약하고 수명을 최대화하는 경로를 제공하는 라우팅 알고리즘을 제안한다. 특히, 어떤 경로에 대한 트래픽 로드가 치우치게 될 때는 시스템 수명을 단축시키게 되므로 트래픽 로드를 경로별로 분산시킨다. 실험 결과를 통해 기존의 WSNs과 WBAN에서의 라우팅 기법들 보다 높은 성능을 보여주는 것을 확인하였다.