Compared with omni-directional antennas, directional antennas have many merits, such as lower interference, better spatial reuse, longer transmission range and the improved network capacity. Directional antennas enable numerous emerging outdoor and indoor applications, which have been addressed in many recent studies. Despite the advances in wireless networks with directional antennas (DAWNs), there are many research challenges in all layers of DAWNs. This paper presents a detailed study on recent advances and open research issues on DAWNs. Firstly, we briefly introduce the classification of directional antennas, antenna radiation patterns, antenna modes as well as the challenges in the physical layer of DAWNs. Then, we present research issues on the MAC layer, followed by the current solutions as well as open research problems. We also discuss the research issues on the routing layer, the transport layer and the performance evaluation of DAWNs. A brief introduction of indoor DAWNs is given in this paper as well.
- Wireless Networks,
- Directional Antennas,
- Medium Access Control,
Available at: http://works.bepress.com/hndai/6/