Network protocol design of M2M-based cooperative relaying

Future wireless networks are expected to support a mixture of real-time applications, such as voice and multimedia streams [85], and non-real-time data applications, such as web browsing, messaging, and file transfers. Compared with wired environments, the associated communication channels and traffic patterns in mobile wireless networks are more unpredictable. Hence all of these applications impose stringent and diversified quality-of-service (QoS) requirements, which cannot be satisfactorily addressed through the traditional communication system. Recently, the availability of low-cost and high-processing-capability hardware that is capable of delivering multimedia content from the environment has fostered the development of wireless multimedia networks [86, 87, 88], that is, networks of resource-constrained wireless devices that can retrieve and deliver multimedia content such as voice and video streams, still images, messaging, and file transfers. As a result, it is predicted that wireless multimedia networks should require energy efficiency and reliable transmission links while keeping satisfactory QoS.