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Full-Text Articles in Physical Sciences and Mathematics
High Rate Concatenated Coding Systems Using Multidimensional Bandwidth Efficient Inner Codes, Robert H. Deng, Daniel J. Jr. Costello
High Rate Concatenated Coding Systems Using Multidimensional Bandwidth Efficient Inner Codes, Robert H. Deng, Daniel J. Jr. Costello
Research Collection School Of Computing and Information Systems
A concatenated coding system using two-dimensional trellis-coded MPSK inner codes and Reed-Solomon outer codes for application in high-speed satellite communication systems was proposed previously by the authors (ibid., vol.37, no.5, p.420-7, May 1989). The authors extend their results to systems using symbol-oriented, multidimensional, trellis-coded MPSK inner codes. The concatenated coding systems are divided into two classes according to their achievable effective information rates. The first class uses multidimensional trellis-coded 8-PSK inner codes and achieves effective information rates around 1 b/dimension (spectral efficiency 2 b/s/Hz). The second class employs multidimensional trellis-coded 16-PSK inner codes and provides effective information rates around 1.5 …
Parity Retransmission Hybrid Arq Using Rate 1/2 Convolutional Codes On A Nonstationary Channel, L. R. Lugand, D. J. Costello, Jr., Robert H. Deng
Parity Retransmission Hybrid Arq Using Rate 1/2 Convolutional Codes On A Nonstationary Channel, L. R. Lugand, D. J. Costello, Jr., Robert H. Deng
Research Collection School Of Computing and Information Systems
A parity retransmission hybrid automatic repeat request (ARQ) scheme is proposed which uses rate 1/2 convolutional codes and Viterbi decoding. A protocol is described which is capable of achieving higher throughputs than previously proposed parity retransmission schemes. The performance analysis is based on a two-state Markov model of a nonstationary channel. This model constitutes a first approximation to a nonstationary channel. The two-state channel model is used to analyze the throughput and undetected error probability of the protocol presented when the receiver has both an infinite and a finite buffer size. It is shown that the throughput improves as the …
High Rate Concatenated Coding Systems Using Bandwidth Efficient Trellis Inner Codes, Robert H. Deng, D. J. Costello, Jr.
High Rate Concatenated Coding Systems Using Bandwidth Efficient Trellis Inner Codes, Robert H. Deng, D. J. Costello, Jr.
Research Collection School Of Computing and Information Systems
High-rate concatenated coding systems with bandwidth-efficient trellis inner codes and Reed-Solomon (RS) outer codes are investigated for application in high-speed satellite communication systems. Two concatenated coding schemes are proposed. In one the inner code is decoded with soft-decision Viterbi decoding, and the outer RS code performs error-correction-only decoding (decoding without side information). In the other the inner code is decoded with a modified Viterbi algorithm, which produces reliability information along with the decoded output. In this algorithm, path metrics are used to estimate the entire information sequence, whereas branch metrics are used to provide reliability information on the decoded sequence. …
Parameter Non-Stationarity In A Model To Estimate The Business Value Of Information Technology, Robert J. Kauffman
Parameter Non-Stationarity In A Model To Estimate The Business Value Of Information Technology, Robert J. Kauffman
Research Collection School Of Computing and Information Systems
Developing robust and refined measures to quantify strategic impacts is a major challenge facing researchers who seek to improve methods for IT investment evaluation. This paper presents a means to test for parameter "non-stationarity" in a model which quantifies the strategic contribution of IT. An iterative "jackknife" procedure is used to diagnose if different local competitive and demographic conditions present in branch banking enhance or suppress leverage on deposit market share associated with membership in an ATM network. Preliminary results suggest this approach will be useful for managers who need to evaluate similar ITs which operate in different environments.