Impact of communication delays and deadline times on distributed processing in packet radio networks

The authors describe a simulation model to aid in the evaluation of time-critical distributed processing scenarios utilizing a multihop packet radio networks. The simulation model includes a user-defined network, spread-spectrum random-access protocols, end-to-end transport functions, and an error model that includes the effects of interference from concurrent transmissions as well as that of an on-off partial band jammer. An abstract description of a typical distributed processing scenario with hierarchical primary and subtask structures, in which a distributed task is described by a `script´, has been devised. In this representation, a distributed task consists of a primary task and a hierarchy of one or more subtasks. Numerical results were obtained through simulations representing a wide variety of task scenarios. Processing scenarios include assignment of task deadlines with levels of task-subtask hierarchy, and redundant processing on multiple hosts