2002 International Telecommunications Symposium

"An ATM switch with distributed cell scheduling is proposed in this paper. By using a crossbar switching structure with large buffers at input ports and small buffers at each crosspoint, the cell scheduling is distributed at input and at crosspoint buffers. The discrimination of incoming cells into service classes at input buffers, and the use of a...

"In this paper a performance study of three CAC (Connection Admission Control) algorithms for ATM networks is presented. The results are obtained through discrete event simulation. Two of the algorithms are based on effective bandwidth concept and the other is a measurement-based method, which uses the actual traffic besides the formal parameters. The...

"Alternant codes over arbitrary finite commutative local rings with identity are con- structed in terms of parity-check matrices. The derivation is based on the factorization of x\u00b0 \u20141 over the unit group of an appropriate extension of the finite ring. An efficient decoding proce- dure which makes use of the modified Berlekamp- Massey algorithm...

"Convolutional codes over groups are defined by Loeliger and Mittelholzer in [6] as being controllable and observable group codes. This means the convolutional codes over groups deserve be studied from both algebraic and system theoretic point of view. We first give a fast review of algebraic facts which will be used to describe the encoder of a group...

"After the initial interest caused by the appearance of turbo codes in 1993, special attention on the implementation has led to their adoption in some of the most important 3G standards. However, future broadband systems (with data rates up to 155 Mb/s) still require a better speed/latency/power performance than those found in current implementations....

"A coding scheme according to service types in AAL2 of ATM-PON are proposed in this paper. The service types and corresponding error correcting codes are indicated by two of six reserved bits in SSTED of AAL2. Several coding schemes such as BCH and convolutional codes are considered under various circumstances. As a result, (127,120) and (127,106) BCH...

"Turbo code can achieve good error performance by iterative decoding, but more iterations result in additional computational complexity and delay. CRC-turbo concatenated code is known to be the most efficient method to reduce the number of iterations. However the performance may be degraded by the edge effect in this scheme like the conventional turbo...

"In this paper, we consider a space-time coded system con- sisting of a rate R = 1/n linear convolutional encoder over GF(p), p a prime, followed by n mappers from GF(p) into a p-ary signal constellation, and by a transmitter with n transmit antennas. At each time, the n p-ary coded symbols are transmitted simultaneously from the n antennas. The...

"A complexity- and delay-efficient simplification of the sum-product algorithm (SPA) for decoding low-density parity-check (LDPC) codes is presented. The key feature of the new algorithm consists of a modification of the complexity-intensive and delay-causing update equations at the check nodes of the factor graph of the LDPC code. The modified update...

"The aim of this paper is to identify the algebraic and geometric structures associated to discrete memoryless channels. The procedure employed to achieve this goal is based on the following steps: knowing the graph associated to discrete memoryless channel, 1) to determine the set of surfaces in which the graph is embedded; 2) to establish the set of...