MultiMAC - an adaptive MAC framework for dynamic radio networking

Software-defined/cognitive radio has recently made the jump from a purely research driven endeavor to one that is now being driven commercially. Such radios offer the promise of spectrum agility and re-configurability through flexibility at the MAC and physical layers. In the wireless domain, it has been shown that hybrid-MAC layer algorithms can lead to improved overall performance in varying network conditions. A hybrid MAC that uses CSMA in low-contention periods and switches to TDMA in high-contention periods can outperform CSMA or TDMA individually. However, such hybrid systems do not offer the flexibility and cognition required of dynamic spectrum networks. In this paper, we describe MultiMAC, a framework and experimental platform for evaluating algorithms that dynamically reconfigure MAC and physical layer properties. MultiMAC acts as a mediating MAC layer and dynamically reconfigures and/or selects from a collection of alternative MAC layers. As a result of monitoring current network metrics, MultiMAC chooses the MAC layer capable of achieving the best performance while ensuring that incoming frames are decoded using the correct MAC layer algorithm. MultiMAC incorporates decision processes to select the appropriate MAC component based on per-node and per-flow statistics. This engine will allow intelligent reconfiguration of the MAC and physical layers in response to changes in external conditions and/or requirements optimizing use of the available spectrum