Broadcast anti-jamming systems

In a traditional anti-jamming system a transmitter who wants to send a sign al to a single receiver spreads the signal power over a wide frequency spec trum with the aim of stopping a jammer from blocking the transmission. In t his paper, we consider the case that there are multiple receivers and the t ransmitter wants to broadcast a message to all receivers such that colludin g groups of receivers cannot jam the reception of any other receiver. We pr opose efficient coding methods that achieve this goal and link this problem to well-known problems in combinatorics, We also link a generalisation of this problem to the Key Distribution Pattern problem studied in combinatori al cryptography. (C) 2001 Elsevier Science B.V. All rights reserved.