ReflectFX Full-duplex communication by mean of reflected power

This work offers a new concept for two-way wireless communication: rather than avoiding self-interference as in half-duplex, or combatting self-interference as in conventional full-duplex, nodes will re-use the received interfering radio-carrier waves to transfer information.

Funded by NSF CAREER #1620902

Team: B. Smida, S. Khaledian, S. Islam, J. Earl, S. Metz, and M. Tomehy
  • B. Smida and S. Khaledian, "ReflectFX : In-band Full-duplex wireless communication by means of reflected power," IEEE Transactions on Communications, vol. 65, no. 5, May 2017.
  • S. Khaledian, F. Farzami, B. Smida and D. Erricolo, "A power-efficient implementation of in-band full-duplex communication system (ReflectFX)," 2016 International Symposium on Signal, Image, Video and Communications (ISIVC), Tunis, 2016, pp. 242-246.
  • B. Smida, "Communication with backscatter modulation," US Patent US20150236841, August 20, 2015.
  • B. Smida and S. Islam, "Full-duplex wireless communication based on backscatter amplification," in Proc of IEEE ICC, Sydney, Australia, July 2014.
  • J. Earl, S. Metz, M. Tomehy, D. Gray and B. Smida, "Backscatter modulation in full-duplex two- way communications," The Journal of Purdue Undergraduate Research, August 2013.

    Inherent Self-Interference Cancellation

    A new analog self-interference cancellation (SIC) technique for in-band full-duplex (IBFD) in single-antenna systems. We use an RF circulator to separate transmitted (Tx) and received (RX) signals. Instead of estimating the self-interference (SI) signal and subtracting it from the Rx signal, we use the inherent secondary SI signal at the circulator, reflected by the antenna, to cancel the primary SI signal leaked from the Tx port to the Rx port.

    Funded by NSF CAREER #1620902

    Team: S. Khaledian, F. Farzami, B. Smida and D. Erricolo
  • S. Khaledian, F. Farzami, B. Smida and D. Erricolo, "Inherent Self-Interference Cancellation for In-Band Full-Duplex Single-Antenna Systems," in IEEE Transactions on Microwave Theory and Techniques, vol. 66, no. 6, pp. 2842-2850, June 2018.
  • S. Khaledian, F. Farzami, B. Smida and D. Erricolo, "Inherent self-interference cancellation at 900 MHz for in-band full-duplex applications," 2018 IEEE 19th Wireless and Microwave Technology Conference (WAMICON), Sand Key, FL, 2018.
  • S. Khaledian, F. Farzami, D. Erricolo and B. Smida, "A Full-Duplex Bidirectional Amplifier With Low DC Power Consumption Using Tunnel Diodes," in IEEE Microwave and Wireless Components Letters, vol. 27, no. 12, Dec. 2017.
  • A Comprehensive Self-interference Model for Single-antenna Full-duplex Communication Systems

    Single-antenna full-duplex communication technology has the potential to substantially increase spectral efficiency. However, limited propagation domain cancellation of single-antenna system results in a higher impact of receiver chain nonlinearities on the residual self-interference (SI) signal. In this paper, we offer a comprehensive SI model for single-antenna full-duplex systems based on direct-conversion transceiver structure considering nonlinearities of all the transceiver radio frequency (RF) components, in-phase/quadrature (IQ) imbalances, phase noise effect, and receiver noise figure. To validate our model, we also propose a more appropriate digital SI cancellation approach considering receiver chain RF and baseband nonlinearities. The proposed technique employs orthogonalization of the design matrix using QR decomposition to alleviate the estimation and cancellation error. Finally, through circuit-level waveform simulation, the performance of the digital cancellation strategy is investigated, which achieves 20 dB more cancellation compared to existing methods.

    Funded by NSF CAREER #1620902

    Team: M. A. Islam and B. Smida
  • M. A. Islam and B. Smida, “A comprehensive self-interference model for single-antenna full-duplex communication systems,” in 2019 IEEE International Conference on Communications (ICC) (Accepted to be published), May 2019.
  • (delay, reliability, rate) tradeoffs in wireless broadcast channels

    Incorporating delay requires re-thinking strategies commonly used in the multi-user setting. Currently, many downlink systems orthogonalize the users as in for example Time Division Multiple Access (TDMA), or conceptually similar Frequency or Code Division multiple access (FDMA, CDMA) schemes. These schemes are simple and practically relevant, but are not in general capacity achieving. For the single antenna, non-fading Gaussian BC, it is known that the Non-orthogonal Multiple Access (NOMA) superposition coding scheme is capacity achieving. In our preliminary work, we asked whether these commonly used schemes, well understood in a capacity / first order sense, perform well in the non-asymptotic. We considered a two-user AWGN BC with full channel state information (CSI) at all nodes. In general, the longer the blocklength over which messages are coded, the lower the probability of error. As such, it is intuitive that a scheme such as the following concatenate-andcode protocol (CCP) and superposition coding may outperform TDMA.

    Funded by NSF CISE # 1900911

    Team: D. Tuninetti, B. Smida, D. Devroye, and H. Seferoglu.
  • D. Tuninetti, B. Smida, N. Devroye and H. Seferoglu, "Scheduling on the Gaussian Broadcast Channel with Hard Deadlines," 2018 IEEE International Conference on Communications (ICC), Kansas City, MO, 2018.
  • M. Mousaei and B. Smida, "Optimizing pilot overhead for ultra-reliable short-packet transmission," 2017 IEEE International Conference on Communications (ICC), Paris, 2017.
  • Z. Ovaisi, N. Devroye, H. Seferoglu, B. Smida and D. Tuninetti, "On Erasure Broadcast Channels with Hard Deadlines," 2018 IEEE International Conference on Communications Workshops (ICC Workshops), Kansas City, MO, 2018.