Speaker
Description
OFDM transmit and receive blocks have long been available to users, developers, and researchers within the GNU Radio ecosystem [1]. These tools are actively maintained by the community, including many domain experts. In previous work, I collaborated with Mr. Barry Duggan to develop an out-of-tree (OOT) block that implements preamble and postamble support for BFSK modulation. This feature significantly improved synchronization between transmitter and receiver—particularly in acoustic communication systems—yielding exponential gains in performance.
My current research focuses on modulating data through dense materials such as steel rail, where traditional BFSK schemes suffer from severe multipath-induced corruption. OFDM, by contrast, offers a highly suitable alternative due to its inherent resilience to multipath fading [2].
One specific challenge that was resolved using the modified OOT flowgraph was the error-free transmission of JPEG images over BFSK-modulated acoustic links. Header packets and Huffman table bits, which are typically sent first in such links, were often lost, or corrupted before synchronization could occur. This led to image decoding failures, where even a single-bit error rendered the file unreadable. [3]
This study investigates the development of preamble/postamble techniques tailored for OFDM, enabling robust synchronization and reliable data transmission. These advances support the broader research objective of achieving dependable acoustic communication in complex and multipath-dominated media.[4] These techniques are crucial for enhancing data integrity and transmission efficiency in environments where multipath effects can severely impact communication reliability, as evidenced by previous findings in the field [5].
To further enhance the reliability of acoustic communication systems in challenging environments, it is essential to explore adaptive techniques that respond dynamically to varying multipath conditions. For instance, the implementation of real-time channel estimation methods, as evidenced by recent studies, can significantly improve the performance of OFDM by adjusting parameters such as subcarrier spacing and modulation depth based on the instantaneous state of the communication channel [6]. Additionally, integrating diversity techniques, such as spatial or frequency diversity, can mitigate the effects of deep fades that often accompany multipath propagation, thereby ensuring more consistent data integrity during transmission [7]. By leveraging these advanced strategies alongside the preamble/postamble enhancements, we can move closer to achieving robust and efficient data transmission in increasingly complex acoustic environments. Future work will focus on implementing these adaptive techniques in real-world scenarios to validate their effectiveness in maintaining high data rates and low bit error rates under varying conditions..
References
[1] M. M. Boter, “Design and implementation of an OFDM-based communication system for the GNU Radio platform,” 2011.
[2] A. Scaglione, S. Barbarossa, and G. B. Giannakis, “Robust OFDM transmissions over frequency-selective channels with multiplicative time-selective effects,” in International Conference on Acoustics, Speech, and Signal Processing, Jun. 2000. doi: 10.1109/ICASSP.2000.861032.
[3] B. A. Banister, B. J. Belzer, and T. R. Fischer, “Robust image transmission using JPEG2000 and turbo-codes,” in International Conference on Image Processing, Sep. 2000. doi: 10.1109/ICIP.2000.900973.
[4] S. Liu, F. Yang, J. Song, F. Ren, and J. Li, “OFDM preamble design for synchronization under narrowband interference,” in International Symposium on Power Line Communications and Its Applications, Mar. 2013. doi: 10.1109/ISPLC.2013.6525859.
[5] “Reliability of Multipath Networks with Optimization of the Location of Inter-Path Communication Nodes,” Mar. 2023. doi: 10.1109/smartindustrycon57312.2023.10110818.
[6] A. C, S. Sundaresan, T. Zacharia, R. Gandhiraj, and K. P. Soman, “An Experimental Study on Channel Estimation and Synchronization to Reduce Error Rate in OFDM Using GNU Radio,” Procedia Computer Science, Jan. 2015, doi: 10.1016/J.PROCS.2015.01.017.
[7] M. A. (Corresponding Author), R. Braun, and Z. Chaczko, “Multipath in Complex Acoustic Channels with an OFDM Solution”.
| Talk Length | 30 Minutes |
|---|---|
| Link to Open Source Code | No code available at this point in time and will develope it in the coming months |
