University of Cambridge > Talks.cam > Inference Group > Joint LDPC Decoding and Timing Recovery Using Code Constraint Feedback

  Browse A-Z

Log in

Cambridge users (raven)details Other usersdetails No account?details

Information on

Subscribing to talksdetails Finding a talkdetails Adding a talkdetails Disseminating talksdetails Help and Documentationdetails

Joint LDPC Decoding and Timing Recovery Using Code Constraint Feedback

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact David MacKay.

In traditional receiver architectures, symbol acquisition and tracking are performed using phase lock techniques that are independent of the channel code decoding process. In burst reception scenarios, bandwidth inefficient piloting must often be embedded in a transmission in order to accelerate acquisition and or to aid symbol time tracking at low signal-to-noise ratios. In this paper we show that outputs from the constraint node side of a bi-partite decoding graph can be used to direct estimation of symbol frequency and phase in a pilotless Low-Density Parity-Check (LDPC) coded transmission. We focus on the problem of a fixed symbol frequency/phase offset between transmitter and receiver and demonstrate that the technique is capable of pulling-in arbitrarily large frequency offsets with complexity that grows logarithmically with offset size. Relatively large timing offsets may occur in receivers that need to determine baud rates autonomously while finer offsets are often due to crystal oscillator mismatches and Doppler-induced frequency shifts. Combining the constraint node observations with a properly calibrated PLL allows successful tracking of both a fixed frequency offset and a random phase walk.

About the Speaker

Christopher R. Jones is with the Jet Propulsion Laboratory in Pasadena California where he works on problems related to Low-Density Parity-Check (LDPC) codes. Specific interests include protograph selection and lifting to achieve low error-floors, universal encoder/decoder architectures, hybridization with ARQ protocols, and integration with timing / carrier recovery techniques. Chris’ background includes a Ph.D.in Electrical Engineeing from the University of California Los Angeles and five years as a communications engineer with Broadcom Corporation.

This talk is part of the Inference Group series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.

Other lists

Sainsbury Laboratory Seminars Quantum Fields and Strings Seminars Type the title of a new list here

Other talks

'Cambridge University, Past and Present' The Exposome in Epidemiological Practice Overview of Research Process Cohomology of the moduli space of curves Tracking neurobiological factors of language developmental difficulties Dynamics of Phenotypic and Genomic Evolution in a Long-Term Experiment with E. coli Single Cell Seminars (August) Microtubule Modulation of Myocyte Mechanics Constructing the virtual fundamental cycle Singularities of Hermitian-Yang-Mills connections and the Harder-Narasimhan-Seshadri filtration Networks, resilience and complexity Uncertainty Quantification of geochemical and mechanical compaction in layered sedimentary basins
 

© 2006-2024 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity