An overview of using directional antennas in wireless networks

Abstract

Compared with omni-directional antennas, directional antennas have many merits, such as lower interference, better spatial reuse, longer transmission range, and 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, and the challenges in the physical layer of DAWNs. We then present research issues on the medium access control (MAC) layer, followed by the current solutions as well as open research problems on the MAC layer of DAWNs. In addition, we also discuss the research issues on the routing layer and the transport layer. Moreover, other research challenges on the performance evaluation of DAWNs and a brief introduction of indoor DAWNs are given in this paper as well. In conclusion, we summarize the current research issues on DAWNs as well as prospects in the future.

Self-optimizing Uplink Outer Loop Power Control for WCDMA Network

“…Increasing number of receiver antennas was recommended and investigated, like 4RX diversity [10], distributed antenna system (DAS) presented at [11] or directional antennas for wireless indoor solution presented at [12]. Furthermore, measurements in live WCDMA network [13] have been performed to propose solutions for WCDMA uplink air interface capacity increase.…”

“…2. If sirMax would be derived by (12), it is obvious that sirMax then would directly depend on measured UL RSSI value. In that case uplink outer loop power control would self-optimize used sirMax value based on current uplink load on the cell.…”

Understanding Link Dynamics in Wireless Sensor Networks with Dynamically Steerable Directional Antennas

“…Sensor and ad-hoc networking with directed antennas opens a lot of challenging research questions including neighbour discovery, medium access control, and routing [25]. For example, Felemban et al present a TDMA-based MAC layer for sectored antennas that bootstraps with a very energy-consuming procedure for matching senders' and receivers' sectors [8].…”

“…As noted above also ad-hoc networking researchers have used directional antennas [25]. For example, Ramanathan et al present a fully working system [27].…”

Directional Medium Access Control (MAC) Protocols in Wireless Ad Hoc and Sensor Networks: A Survey

“…On the other hand, for circular-based type of pure RTS/CTS-based DMAC protocols, there is only a DRTS/CCTS-based DMAC protocol. There are survey papers for DMAC protocols for WAHNs in the literature [1][2][3][4][5][6]. The differentiating factor in this survey paper for DMAC protocols is in its main contribution.…”