Abstract:

Directional antennas have received considerable attention due to the spatial-reuse they provide which increases the potential capacity of wireless networks.But the topological connectivity of beam forming antennas in multihop wireless networks is more complicated than topologies for wireless networks with omni-directional antennas.Topology control aims to maintain network connectivity and improve performance for Ad hoc networks using directional antennas.A topology control algorithm for Ad hoc networks with steered beam directional antennas is proposed.The topology is controlled not only by adjusting the transmission powers of nodes but also by changing the directional antenna’s direction.The algorithm preserves the connectivity of the resulting topology.At the same time，the resulting network topology reduces energy consumption，decreases traffic interference and improves network throughput while transmission power reduced.Simulation results show that the proposed algorithm significantly improves the network performance.

Key words: Ad hoc networks, directional antennas, topology control, energy efficient

摘要： 定向天线能显著提高无线系统的性能和容量，但采用定向天线的自组网拓扑构建问题比全向天线网络复杂。拓扑控制是一种保证网络连通和性能优化的有效手段。基于自适应波束定向天线模型提出一种拓扑控制算法，确定天线的主波束朝向，调整节点的发射功率构建拓扑。算法在保证网络连通的基础上，利用主波束的高增益，降低了节点的发射功率，从而降低节点能耗；同时利用定向天线方向性强的特点，减少了节点间干扰，提高了网络吞吐量。仿真结果表明，算法显著提高了网络性能。

关键词: 自组网, 定向天线, 拓扑控制, 能量效率