The capacity of wireless ad hoc networks can be increased by using multiple radio channels. But due to interference the capacity is still not fully utilized. This is caused by the limited number of available radio channels. The interference problem can be reduced using directional beams instead of omni-directional beams. This paper presents a novel cross-layer approach to use multiple radio channels with directional antennas. We are using three different radio channels. Each node has three fixed directional beams having fixed beamwidth and with different radio frequency. Two nodes can communicate when both the sending and receiving beams are pointing towards each other using the same frequency channel. In this study the directions of beams cannot be changed dynamically. A modified version of Ad hoc On-demand Distance Vector (AODV) routing protocol has been used. Simulation results show that our approach outperforms other methods using three different radio channels with omni-directional antennas
In Wireless Sensor Networks (WSNs), nodes closer to an event are able to detect the event earlier and more accurately, thus contain more important information. Also, tiny nodes are usually scarce of energy and a major portion of their energy is used through communication. Therefore saving the energy by allowing only a limited number of communications is desirable in designing protocols for WSNs. We propose a data-driven Medium Access Control (MAC) protocol which allows only the more useful information to enter into the medium by using a modified contention mechanism and also suppressing other spatially-correlated data that are of less importance. Simulation results show that the proposed MAC outperforms the existing ones in terms of event reporting delay and packet delivery ratio for urgent data.