Andrew P. Worthen

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— Iterative algorithms are an attractive approach to approximating optimal, but high-complexity, joint channel estimation and decoding receivers for communication systems. We present a unified approach based on factor graphs for deriving iterative message-passing receiver algorithms for channel estimation and decoding. For many common channels, it is easy(More)
We develop a belief-propagation-based joint decoding and channel state estimation algorithm for low-density parity check codes on fading channels with memory. The excellent empirical performance of LDPC codes on the AWGN channel and the possibility of arranging the code memory relative to the channel correlation suggests that LDPC codes have the potential(More)
This paper presents techniques for achieving high throughput in delay-constrained, multihop wireless communication networks with time-varying link connectivity. We develop a rate-controlled, multipath strategy using network coding, and compare its performance with that of multipath flooding and with the performance of traditional single-path strategies.(More)
High speed satellite-based data networks are highly desirable for a variety of mobile applications. In order to inter-operate with existing networks, satellite-based systems must support TCP/IP traffic. However, TCP performs poorly on land-mobile satellite channels because of large propagation delays and frequent correlated packet loss. The use of a link(More)
| Design of low-energy communications systems requires attention to power consumption in the overall system design and the algorithm implementations. We consider design of a communications system incorporating digital transmission and receiver lters, and error-control coding. Various well-known channel codes including turbo codes, block codes, and(More)
This work addresses the challenge in providing reliable communication in mobile networks with intermittent, on/off links through the use of a routing overlay designed to deal with these channel impairments. Link blockage is a predominant feature of mobile networks operating at 10+ GHz frequencies, and current techniques are ill-suited to address this(More)