Mesh Scaleable Routing (MSR™) Protocol
At the heart of Motorola's ad hoc networking technology is a highly efficient routing protocol designed specifically for use in Multi-Hopping™ wireless mesh networks – the Mesh Scalable Routing (MSR™) protocol. The MSR protocol is designed to work efficiently with or without centralized wireless infrastructure equipment (i.e. wired APs or stations), which enables nodes to seamlessly transition between "infrastructure-enhanced" and client-based "peer-to-peer" networks.

MSR technology enables dynamic, self-forming, self-healing, Multi-Hopping™ routing between participating nodes in an ad hoc (mesh) network. The MSR protocol is a hybrid routing approach that leverages proactive and reactive routing techniques via situation-aware networking. With this methodology , network topology dynamics, local RF conditions and degree of node mobility influence the routing metrics used on a moment-by-moment basis.

The MSR protocol is self-optimizing and delivers ultra-fast route convergence for mobile or RF hostile networks, while minimizing overhead on a per node and system wide basis. This unique technique reduces the flooding overhead and latency usually associated with the route discovery process of classical reactive protocols, as well as the high routing overhead usually associated with classical proactive protocols. The situation-aware routing algorithms used in the MSR protocol greatly enhances the scalability of the network, while supporting high mobility in real world, wide area networks. In addition, the algorithms used have been demonstrated to be free of routing loops in all topology and network conditions.

MSR technology leverages a real-time assessment of connectivity and other environmental factors to determine routes between nodes as well as end-to-end paths through the network. It learns of these conditions via a set of metrics supplied by ATP™ services (see below). This continuous assessment of network and RF conditions also helps it accomplish "make before break" routing, resulting in smooth handoffs, seamless connectivity, and reliable communications for high speed mobile networks. Strong interaction with ATP services also enables the MSR protocol to characterize the "bi-directionality" of a link. That is, the extent to which a wireless link can support symmetric data rates to and from a pair of nodes. The ability to characterize and assess asymmetric links is critical for real world wireless routing.

Adaptive Transmission Protocol (ATP™) Services
Many possible environmental conditions can interfere with data transmitted wirelessly, particularly broadband data in high speed mobility situations. Multipath, shadowing, fast fading, and interference (both intentional and unintentional) can all cause excessive packet loss at the receiver.

To deal with these conditions, the transmitter will be instructed to back down its data rate for a period of time. However, these RF conditions can appear on a highly dynamic basis. If the data rate is decreased for longer than the condition exists, link reliability may be satisfactory, but throughput is not maximized. If the data rate is raised too quickly while the condition continues, the resulting packet loss can also lead to poor data throughput. The purpose of ATP services is to enable the MSR protocol to balance the requirements of a reliable transmission while assuring the highest data throughput rate possible on a packet by packet basis.

In addition to providing link quality metrics, ATP services inform the MSR protocol of the impact that transmit power level has on network capacity for a given link. For example, the high transmit power required by a particular link may create interference and uses channel resources (i.e. spectrum) unnecessarily. ATP services provide multiple physical layer statistics to the MSR protocol, which then becomes power-aware. At the same time, ATP services actively determine the fastest data rate that can be achieved on a packet by packet basis for each link.

Conclusion
MSR/ATP technology intelligently optimizes the combination of link reliability, transmit power and data rates in order to minimize energy use and system interference while simultaneously maximizing data throughput and spectrum efficiency.