Kumiko Kanai

Forward error correction control on AAL 5: FEC-SSCS

ATM networks is realized as the future communication platform that accommodate a variety of communication services. A novel cell-level FEC (forward error correction) scheme at SSCS of AAL type 5 for error-free data transmission services is proposed and evaluated. In the proposed cell-level FEC scheme, both the length of user data (e.g. IP packet) and appended redundant data can be modified based on the senders local decision without any end-to-end parameter re-negotiation. The writing and reading order regarding an interleave matrix for the cell-level FEC algorithm are the same, in order to perform pipelining data transmission. The end-to-end data transmission latency and the amount of retransmission packets due to packet error at the receiver entity are evaluated by computer simulation with a correlated cell dropping process. Simulation results show that the benefits of cell-level FEC scheme for the error-free data transmission services, i.e., by use of a cell-level FEC scheme, the amount of retransmitted packets can be reduced, even if the average latency for end-to-end data transmission increases slightly.

Fault-Tolerant Broadcasting in Binary Jumping Networks

The following results are shown. Let N be the number of processors in the network. When N is a power of 2, Iog2N+f+1 rounds suffice for broadcasting in the binary jumping network if at most f processors and/or links have failed and f≤log2N−1. For an arbitrary N, ⌈log2N⌋ + f+2 rounds suffice for broadcasting in the binary jumping network if at most f processors and/or links have failed and f≤⌈log2N⌋−2. It is also shown that the vertex connectivity of the binary jumping network with N nodes is ⌈log2N⌋.

Broadcasting in Faulty Binary Jumping Networks

We discuss the fault tolerance of an information disseminating scheme in a processor network called a binary jumping network. The following results are shown. Let N be the number of processors in the network. When N is a power of 2, log2N + � + 1 rounds suffice for broadcasting in the binary jumping network if at most � processors and/or links have failed and � � log2N � 1. For an arbitrary N, log2N] + � + 2 rounds suffice for broadcasting in the binary jumping network if at most � processors and/or links have failed and � � log2N] � 2. For an arbitrary N and � = log2N] � 1, 3log2N] rounds suffice for sending a message to a destination with a certain distance from the source processor. This result implies that for some N and arbitrary � = log2N] � 1, 3log2N] rounds suffice for broadcasting. For other N and arbitrary � = log2N] � 1, the bound given in this paper is larger than 3log2N].