Supporting code mobility and dynamic reconfigurations over Wireless MAC Processor Prototype

Mobile networks for Internet Access are a fundamental segment of Internet access net- works, where resource optimization are really critical because of the limited bandwidth availability. While traditionally resource optimizations have been focused on high effi- cient modulation and coding schemes, to be dynamically tuned according to the wireless channel and interference conditions, it has also been shown how medium access schemes can have a significant impact on the network performance according to the application and networking scenarios. This thesis work proposes an architectural solution for supporting Medium Access Con- trol (MAC) reconfigurations in terms of dynamic programming and code mobility. Since the MAC protocol is usually implemented in firmware/hardware (being constrained to very strict reaction times and to the rules of a specific standard), our solution is based on a different wireless card architecture, called Wireless MAC Processor (WMP), where standard protocols are replaced by standard programming interfaces. The control architecture developed in this thesis exploits this novel behavioral model of wireless cards for extending the network intelligence and enabling each node to be remotely reprogrammed by means a so called “MAC Program”, i.e. a software element that defines the description of a MAC protocol. This programmable protocol can be remotely injected and executed on running network devices allowing on-the-fly MAC reconfigurations. This work aim to obtain a formal description of the a software defined wireless network requirements and define a mechanism for a reliable MAC program code mobility throw the network elements, transparently to the upper-level and supervised by a global con- trol logic that optimizes the radio resource usage; it extends a single protocol paradigm implementation to a programmable protocol abstraction and redefines the overall wire- less network view with support for cognitive adaptation mechanisms. The envisioned solutions have been supported by real experiments running on different WMP proto- types , showing the benefits given by a medium control infrastructure which is dynamic, message-oriented and reconfigurable.