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Sub- Nyquist Sampling of Wideband Signals. Optimization of the choice of mixing sequences. Itai Friedman Tal Miller Supervised by: Deborah Cohen Technion – Israel Institute of Technology. Presentation Outline. System Description Project Objective Main Project Stages.
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Sub-Nyquist Sampling of Wideband Signals Optimization of the choice of mixing sequences Itai Friedman Tal Miller Supervised by: Deborah Cohen Technion – Israel Institute of Technology
Presentation Outline • System Description • Project Objective • Main Project Stages
Spectrum Sparsity • Spectrum is underutilized • In a given place, at a given time, only a small number of PUs transmit concurrently Shared Spectrum Company (SSC) – 16-18 Nov 2005
Model ~ ~ ~ ~ • Input signal in Multiband model: • Signal support is but it is sparse. • N – max number of transmissions • B – max bandwidth of each transmission • Output: • Reconstructed signal • Blind detection of each transmission • Minimal achievable rate: 2NB << fNYQ Mishali & Eldar ‘09
The Modulated Wideband Converter (MWC) ~ ~ ~ ~ Mishali & Eldar ‘10
MWC – Recovery ~ ~ ~ ~ Now we can solve a linear set of equations for input signal:
MWC – Mixing & Aliasing • System requirement: are periodic functions with period called “Mixing functions” • Examples for : … 1 -1 Frequency domain
Project Objective • Questions: • What are the best Mixing functions ? • Focusing on {+1,-1} functions, what properties should the sequences have? • Main Objective: • Finding optimal Mixing function sequences for effective reconstruction
What is our part in the system? • Analog signal generation • Mixing • Filtering • Sampling • Recovery • The code already exists, we modify the mixing functions generator
Main Project Stages • Deepening the understanding of the theory behind the system • Understanding the current achievements in the mixing functions field • Defining sequences criteria for optimal system performance • Simulating the different sequences in the MWC system using Matlab • Determining what are the optimal sequences based on simulations and publicating the findings
Thank you For listening And thanks Debby for the basis to our presentation