Abstract: The study of energy constrained routing protocols in Ad Hoc networks is attracting more attention currently.The typical routing protocols presented by the MANET of IETF are shortest routing，that is，the least hops and not considering the energy aware problem.Because the Ad Hoc networks are energy constrained system with the portable devices，it is a very important metric to evaluate the protocols whether networks have a longer lifetime or not.Based on the mobile node energy level and using the different forwarding probabilities，this paper presents a probability based routing protocols—PBR.By simulating the two routing protocols AODV and PBR，the results show that PBR improves the energy consumption of system obviously，at the same time，it has a longer network lifetime and better delay than AODV.

Key words: energy level, energy constrained, Ad Hoc networks, routing protocol, probability forwarding

摘要： Ad Hoc网络节点能量受限的路由协议的研究是目前的一个热点，IETF的MANET小组提出的几种经典的路由协议，属于最短路由，即最小跳数路由，没有考虑能量因素。由于Ad Hoc网络中的节点是由电池供电，整个网络是一个能量受限系统，如何节省节点的能量，尽可能延长网络的可操控时间逐渐成为衡量路由协议性能的重要指标。基于移动节点的能量级别，采取不同的转发概率，提出了一种Ad Hoc网络基于概率的路由协议——PBR，并与AODV协议进行了性能比较，仿真结果显示，PBR明显改善了系统的能量消耗，延长了网络的存活时间，并且具有较优的可扩展性。

关键词: 能量级别, 能量受限, Ad Hoc网络, 网络协议, 概率转发