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Abstract-A serially concatenated coding system which can operate without channel state information (CSI) with use of a simple channel estimation technique is presented. This channel estimation technique utilizes the inner decoder's a posteriori probability (APP) information about the transmitted symbols to form a channel estimate for each symbol interval, and is termed APP channel estimation. The serially concatenated code (SCC) is comprised of an outer rate 2/3 binary error control code, separated by a bit interleaver from an inner code consisting of an 8-PSK bit mapping and differential 8-PSK modulation. Coherent decoding provides bit error rate (BER) performance 0.6 dB from 8-PSK capacity for large interleaver sizes. APP channel estimation decoding without initial CSI over constant and random walk phase models shows near-coherent results, with fractions of a dB performance loss for random walk and linear phase models.

The South Dakota School of Mines andTechnology began a revision of the freshman engineering curriculum in 1997. Beginning with a pilot program of 25 students, the program is now required for virtually all firstyear engineering students. The program, FC 2000, utilizes a project -based learning approach and features student teams to integrate material in general engineering, mathematics, science and English. Small projects (2-3 per semester) are designed to give students an exposure to engineering design in a variety of engineering disciplines. Project components include designing and conducting experiments, analyzing data, and presentation of technical data. In this paper we present a model for the first year curriculum, preliminary assessment results, and plans for future integration.

A method is proposed for computing with unreliable nanoscale devices that have a high rate of transient errors. Errors are corrected using a probabilistic circuit in which device noise is leveraged as a computational asset. Example designs that achieve a low output bit error probability are presented. The effect of permanent defects is also evaluated, and transient device noise is found to be beneficial for correcting hard defects for defect rates of as high as 0.1% and transient fault rates above 1%. When compared with existing fault-tolerant methods, the sample design requires considerably fewer redundant gates to achieve reliable operation. These results predict that some degree of engineered randomness may prove to be a useful signal-processing feature in future nanoelectronic systems.

Abstract-This paper examines different parity-check node decoding algorithms for low-density parity-check (LDPC) codes, seeking to recoup the performance loss incurred by the min-sum approximation compared to sum-product decoding. Two degreematched check node decoding approximations are presented which depend on the check node degree dc. Both have low complexity and can be applied to any degree distribution. Simulation results show near-sum-product decoding performance for both degree-matched check node approximations, for regular and irregular LDPCs.

Abstract-This paper explores integrated source-channel decoding, driven by wireless sensor network applications where correlated information acquired by the network is gathered at a destination node. The collection of coded measurements sent to the destination, called a source-channel product codeword, has redundancy due to both correlation of the measurements and the channel code used for each measurement. At the destination, source-channel (SC) decoding of this code combines decoding using (i) the deterministic structure of the channel-coded individual measurements and (ii) the probabilistic structure of a prior model, called the global model, that describes the correlation structure of the SC product codewords. We demonstrate the utility of SC decoding via MAP SC decoding experiments using a (7,4,3) Hamming code and a Gaussian global model. We also show that SC decoding can exploit even the simplest possible code, a single-parity check code, using a MAP SC decoder that integrates the parity check constraint and global model. We describe the design of a low-complexity message-passing decoder and show it can improve performance in the poor-quality channels often found in multi-hop wireless data-gathering sensor networks.

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