Data broadcasting with feedback for wireless LANs

A broadcast medium, transmitting the same message to a number of stations is relatively simple. An example is the teletext procedure which broadcasts messages cyclically. In this procedure stations have to wait a full cycle for the next transmission if a part of the message is either lost or is faulty. Sometimes however it is important that all the receiving stations receive the message within a certain time. The time necessary to transmit a message to all stations may decrease considerably if some kind of feedback from the receiving stations to the transmitting station is used. To determine the upper speed limit of data broadcasting with feedback, a selective reject procedure with infinite fast feedback, being the most efficient feedback error correction method, has been analysed. For a comparison, the transmission of messages with the existing cyclic teletext procedure has been analysed too. Finally a data broadcasting protocol with feedback has been designed and simulated. A special feature of this protocol is that it makes use of the properties of the broadcast channel for the feedback signals too. Besides that the number of receivers may vary dynamically.