Advantages of Dual Channel MAC for Wireless Sensor Networks

Traditional low cost radios for wireless sensor networks
operate with one frequency channel at any given time.
However, recent advances in radio hardware for WSNs made
available transceivers that can support two simultaneous channels.
In this work, we investigate the benefits of using two parallel
independent frequency channels at the MAC layer. In particular,
the paper introduces a technique of Dual Channel Multiple
Access with Adaptive Preamble (DCMA/AP). The protocol uses
two separate frequencies for data and control packets to avoid
the use of handshake mechanisms (e.g. RTS/CTS) in order to
reduce energy consumption and packet delay. To address the
hidden and exposed terminal problems, DCMA/AP enables a
receiver to send a busy tone signal on the control channel to
notify neighbors that an ongoing reception is in progress. As a
result, packet collisions are nullified with an increase of node
throughput. Furthermore, an adaptive preamble mechanism in
DCMA/AP avoids secondary processes of node synchronization
together with a reduction of idle listening of receiving nodes
that are considered to be one of the major sources of energy
consumption in wireless sensor networks. Finally, DCMA/AP
introduces a mechanism of opportunistic crossover speeds up the
process of packet forwarding by pre-announcing the successive
candidate node intended to receive the packet.