A Window Protocol for Transmission of Time-Constrained Messages

In this paper, we propose and study a new window protocol suitable for transmitting time-constrained messages in a multiaccess network. Our protocol differs from traditional window protocols in that it explicitly takes time constraints into account. In our protocol, the window is formed based on the latest time to send a message (LS). A major advantage of our window protocol is that a newly arriving message is immediately considered for transmission if its LS is less than that of all pending messages in the system. As a result, our new protocol closely approximates the optimal minimum-laxity-first policy. A performance evaluation through simulation shows that the new window protocol performs well in a wide range of environments, even under overloaded conditions. ate without taking past history of the channel into account. This category includes ALOHA [l] and various CSMA and CSMS/CD protocols [ 101. 2) Inference seeking protocols: These protocols make inference on the collision history, and usually solve collisions by partitioning some parameter space of the messages. Various tree, window, stack, and urn protocols [2], [41, [5], [71, [81, [ l l ] , [131, [31]-1331 belong to this category. 3) Deterministic or Collision -free protocols: These protocols work in such a way that collisions do not occur at all. The time division multiple-access protocols (TDMA), the bit-map protocol [ 121, the broadcast recognition with alternative pri