. The new algorithm is simpler, faster, and requires n-d-1 fewer message transmissions than previously proposed optimal k-fault-tolerant broadcast schemes. keywords: Hypercube, Fault-tolerant, Broadcasting 1 supported by the National Sciences and Engineering Research Council of Canada 494 1 Introduction

Although the capacity of multiple-input/multiple-output (MIMO) broadcast channels (BCs) can be achieved by dirty paper coding (DPC), it is difficult to implement in practical systems. This paper investigates if, for a large number of users, simpler schemes can achieve the same performance

. The superiority of the DDF protocol is shown to be more significant in the cooperative broadcast channel. The situation is reversed in the CMA channel where we propose a new AF protocol that achieves the optimal tradeoff for all multiplexing gains. A distinguishing feature of the proposed protocols in the three

) requirement in a dynamic multi-hop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the best qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave

All-to-all broadcasting (Gossiping) is the process of information dissemination in a communication network. Each member in the network has a message to transmit to all other members of the network. We proposed a k-fault- tolerant scheme for a faulty d-dimensional hypercube with n = 2 nodes where

combination of a traditional broadcast protocol and a contentbased routing protocol. We present the combined scheme and its requirements over the broadcast protocol. We then detail the content-based routing protocol, highlighting a set of optimization heuristics. We also present the results of our evaluation

of the intended signal. This scheme has been shown to be optimal. We conclude that present methods of allocating different frequency bands to different transmitters are necessarily suboptimal.

. This paper investigates fault-tolerant broadcasting in star networks. We propose a non-adaptive single-port broadcasting scheme in the n-star network such that it tolerates n 0 2 faults in the worst case and completes the broadcasting in O(n log n) time. The existence of such a broadcasting

failures in optimal time Tn (k). In this paper we study B k (n), the minimum number of communication lines of any minimal k--fault tolerant broadcast network on n processors. We give the value of B k (n) for several values of n and k and, in case k ! blog nc, give almost--minimum k-fault--tolerant

, for both problems, we review and extend some existing broadcast encryption schemes, in order to gain fault tolerance