Elastic Routing in Wireless Ad Hoc Networks With Directional Antennas

Throughput scaling laws of an ad hoc network equipping directional antennas at each node are analyzed. More specifically, this paper considers a general framework in which the beam width of each node can scale at an arbitrary rate relative to the number of nodes. We introduce an elastic routing protocol, which enables to increase per-hop distance elastically according to the beam width, while maintaining an average signal-to-interference-and-noise ratio at each receiver as a constant. We then identify fundamental operating regimes characterized according to the beam width scaling and analyze throughput scaling laws for each of the regimes. The elastic routing is shown to achieve a much better throughput scaling law than that of the conventional nearest-neighbor multihop for all operating regimes. The gain comes from the fact that more source–destination pairs can be simultaneously activated as the beam width becomes narrower, which eventually leads to a linear throughput scaling law. In addition, our framework is applied to a hybrid network consisting of both wireless ad hoc nodes and infrastructure nodes. As a result, in the hybrid network, we analyze a further improved throughput scaling law and identify the operating regime where the use of directional antennas is beneficial. Index Terms Ad hoc network, beam width, directional antenna, elastic routing, hybrid network, multihop routing, throughput scaling law. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2014R1A1A2054577). The material in this paper was presented in part at the IEEE International Symposium on Information Theory, Honolulu, HI, June/July 2014 [31]. J. Yoon is with the Attached Institute of ETRI, Daejeon 305-390, Republic of Korea. (E-mail: [email protected]). W.-Y. Shin (corresponding author) is with the Department of Computer Science and Engineering, Dankook University, Yongin 448-701, Republic of Korea (E-mail: [email protected]). S.-W. Jeon is with the Department of Information and Communication Engineering, Andong National University, Andong 760-749, Republic of Korea (E-mail: [email protected]). 2