Multiband Sparse Channel Reconstruction with OFDM

This repository provides MATLAB implementations of three sparse recovery algorithms-OMP, mmSplicer, and Net-SpaRSA---applied in the context of wireless channel reconstruction using multiband sensing with OFDM waveform. These algorithms aim to reconstruct the Channel Impulse Response (CIR) from multiple narrowband Channel Frequency Response (CFR) observations over a 160 MHz total bandwidth.

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Project Summary

Multiband splicing is a technique that reconstructs wideband wireless channels by combining multiple narrowband measurements (e.g., 8x20 MHz subbands). In this work, we evaluate the performance of three sparse recovery methods by:

• Simulating or measuring wideband CFRs using 160 MHz OFDM signals.
• Emulating narrower-band measurements by selecting subbands from the wideband CFR.
• Applying sparse recovery algorithms to reconstruct the CIR using partial subband data (e.g., 50% subbands).
• The data is generated through simulation and measurements:
  • simulation data
  • cable measurements
  • over-the-air at 2.4 GHz and 60 GHz

All CFR and CIR data are stored in binary files and used as input to the algorithms.

Repository Structure

.
├── algorithms
│   ├── mmSplicer
│   │   ├── first_stage.m
│   │   ├── mmSplicer_main.m        # Main script for mmSplicer
│   │   ├── mmSplicer_OMP.m
│   │   └── PreProcessing.m
│   ├── Net-Sparsa
│   │   ├── group_l2norm.m
│   │   ├── group_vector_soft.m
│   │   ├── main_sparsa.m           # Main script for Net-SpaRSA
│   │   ├── SpaRSA.m
│   │   └── vector_soft.m
│   └── OMP
│       ├── Continuous_OMP.m
│       ├── main_omp.m              # Main script for OMP
│       └── PreProcessing.m
├── README.md
└── res
    ├── cable
    │   ├── cfr.bin
    │   └── cir.bin
    ├── over-the-air
    │   ├── 2.4ghz
    │   │   ├── cfr.bin
    │   │   └── cir.bin
    │   └── 60ghz
    │       ├── cfr.bin
    │       └── cir.bin
    └── simulations
        ├── cfr.bin
        └── cir.bin

Algorithms Overview

Algorithm	Description	Main Script
OMP	Orthogonal Matching Pursuit, adapted from [1]	main_omp.m
mmSplicer	Our custom two-stage extension of OMP designed for wireless channel reconstruction	mmSplicer_main.m
Net-SpaRSA	Adaptation of SpaRSA for sparse reconstruction in multiband OFDM [2,3]	main_spasa.m

Citation

[1]: M. B. Khalilsarai, B. Gross, S. Stefanatos, G. Wunder, and G. Caire, “WiFi-Based Channel Impulse Response Estimation and Localization via Multi-Band Splicing,” in IEEE Global Communications Conference (GLOBECOM 2020), Taipei, Taiwan: IEEE, Dec.2020
[2]: S. J. Wright, R. D. Nowak, and M. A. Figueiredo, “Sparse reconstruction by separable approximation,” IEEE Transactions on Signal Processing, vol. 57, no. 8, pp. 2479–2493, Jul. 2009.
[3]: https://www.lx.it.pt/~mtf/SpaRSA/\

Contact

• Sigrid Dimce, TU-Berlin, dimce@ccs-labs.org