Full-Duplex Radio
Increasing demand for high data rates with the proliferation of wireless services is calling for powerful communication technologies that exploit the current spectrum more efficiently. Half-duplex (HD) systems, employ two orthogonal channels to transmit and receive, and thus cannot achieve the maximal spectral efficiency. Full-duplex (FD) system however, enables simultaneous transmission and reception at the same time in the same frequency band and can potentially double the link capacity. However, self interference (SI) at the front end of the receiver, which is caused by the transmitter antennas of a FD node to its own receiver antennas and co-channel interference (CCI) from uplink users to downlink users are some of the challenges in the implementation of FD systems. Fortunately, experimental research of late has shown that it possible to cancel this SI and CCI to the extent that such systems are actually feasible in the real world.

Research
Members Involved : A. Bishnu, J. Zhang, H. Luo, N. Garg, I.Shahzadi

In our research group, we focus on the energy efficient design of  transceivers for FD MIMO CR ad-hoc and cellular networks. Limiting factors such as SI, CCI under the effect of limited dynamic range at the transmitter and receiver and norm-bounded channel uncertainties are considered. The problems we face are usually non-convex and hence globally optimal solutions are difficult to obtain. We focus on designing and proposing several algorithms (eg. SDP based, cutting-set etc.) to solve these problems. 

Publications​
  1. S. Biswas, A. Bishnu, F Khan, T Ratnarajah, “In-Band Full-duplex Dynamic Spectrum Sharing in Beyond 5G Networks,'' IEEE Communications Magazine, Vol. 59, Issue 7, pp. 54-60, July 2021. 
  2. A. Bishnu, M. Holm, and T. Ratnarajah, ''Performance Evaluation of Full-Duplex IAB Multi-Cell and Multi-User Network for FR2 Band,'' IEEE Access, Vol.9, pp. 72269-72283, May 2021. 
  3. H. Luo, M. Holm, and T. Ratnarajah, ``On the Performance of Active Analog Self-Interference Cancellation Techniques for Beyond 5G Systems'', China Communications, in press, May 2021.
  4. J. Zhang, N. Garg, M. Holm and T. Ratnarajah, "Design of Full-Duplex Millimeter-Wave Integrated Access and Backhaul Networks," IEEE Wireless Communications Magazine, Vol. 28, no. 1, pp. 60-67, Feb. 2021.
  5. H. He, S. Biswas, P. Aquilina and T. Ratnarajah, "Performance Analysis of Multi-Cell Full-duplex Cellular Networks," IEEE Access, Vol. 8, 206914-206930, 2020.
  6. S. Biswas, K. Singh, O. Taghizadeh and T. Ratnarajah, "Design and Analysis of FD MIMO Cellular System in coexistence with MIMO Radar," IEEE Trans on Wireless Communications, Vol.19, Issue 7, pp. 4727-4743, July 2020.
  7. K. Singh, K. Wang, S. Biswas, Z. Ding, F. Khan, and T. Ratnarajah, "Resource Optimization in Full Duplex Non-orthogonal Multiple Access Systems," IEEE Trans on Wireless Communications, Vol. 18, No. 9, pp. 4312-4325, Sep. 2019.
  8. S. Biswas, K. Singh, O. Taghizadeh and T. Ratnarajah, "Coexistence of MIMO Radar and FD MIMO Cellular Systems with QoS Considerations," IEEE Trans on Wireless Communications, Vol. 17, No. 11, pp. 7281-7294, Nov. 2018. ​
  9. K. Singh, S. Biswas, T. Ratnarajah and F. H. Khan, "Transceiver Design and Power Allocation for Full-Duplex MIMO Communication Systems with Spectrum Sharing Radar," IEEE Trans. on Cognitive Communications and Networking, Vol. 4, No. 3, pp. 556-566, Sep. 2018. 
  10. P. Aquilina and T. Ratnarajah, "Linear Interference Alignment in Full-Duplex MIMO Networks with Imperfect CSI," IEEE Trans. on Communications, Vol. 65, Issue 12, pp. 5226-5243, Dec. 2017.
  11. P. Aquilina, A. C. Cirik, and T. Ratnarajah, "Weighted Sum Rate Maximization in Full-Duplex Multi-User Multi-Cell MIMO Networks," IEEE Trans. on Communications, Vol. 65, Issue 4, pp. 1590-1608, April 2017.
  12. A. C. Cirik, S. Biswas, and T. Ratnarajah, "Robust Transceiver Design in Full-Duplex MIMO Cognitive Radios" IEEE Trans. on Vehicular Technology, Vol. 67, Issue 2, pp. 1313-1330, Feb. 2018.
  13. J. Xue, S. Biswas, A. C. Cirik, H. Du, Y. Yang, T. Ratnarajah, and M. Sellathurai, "Transceiver Design of Optimum Wirelessly Powered Full-Duplex MIMO IoT Devices,"  IEEE Trans on Communications, Vol 66, pp. 1955-1969, May 2018..
  14. A. C. Cirik, S. Biswas, S. Vuppala, and T. Ratnarajah, "Beamforming Design for Full-Duplex MIMO Interference Channels-QoS and Energy-Efficiency Considerations," IEEE Trans. on Communications, Vol 64, No 11, pp. 4635-4651, Nov. 2016.
  15. A. Cirik, M. C. Filippou, and T. Ratnarajah, "Transceiver Design in Full-Duplex MIMO Cognitive Radios under Channel Uncertainties," IEEE Trans. on Cognitive Communications and Networks, Vol. 2, No. 1, pp. 1-14, March 2016.
  16. A. Cirik, L. Zhou, and T. Ratnarajah, "Linear Transceiver Design With Per-Antenna Power Constraints in Full-Duplex Multi-user MIMO Systems," IEEE Wireless Communications Letters, pp. 412-415, Vol 5, No. 4, Aug. 2016.
  17. A Cirik, S Biswas, S. Vuppala, and T Ratnarajah, “Robust Transceiver Design for Full Duplex Multi-user MIMO Systems,” IEEE Wireless Communications Letters, Vol. 5, No. 3, pp. 260-263, June 2016..
  18. A Cirik, S Biswas, O Taghizadeh, T Ratnarajah, “Robust Transceiver Design in Full-Duplex MIMO Cognitive Radios,” In Proc. the IEEE International Conference on Communications, Kuala Lumpur, Malaysia, May 23-27, 2016.
  19. A. C. Cirik, O. Taghizadeh, R. Mathar, T. Ratnarajah, "QoS Considerations for Full Duplex Multi-user MIMO Systems," IEEE Wireless Communications Letters, Vol. 5, No. 1, pp. 36-39, Feb. 2016.
  20. A. C. Cirik, J. Xue, S. Biswas, T. Ratnarjah, and M. Sellathurai, "Transceiver design of Optimum wirelessly powered Full-Duplex MIMO Interference Channel," In Proc IEEE 17th International Workshop on Signal Processing Advances in Wireless Communications, Edinburgh, UK, July 3-6, 2016.
  21. A. C. Cirik, O Taghizadeh, L. Lampe, and T. Ratnarajah, "A Different Approach in Transceiver Design for Full-Duplex MIMO Systems,"  In Proc. the IEEE Vehicular Technology Conference, Montréal, Canada, Sep 18-21, 2016.
  22. A. C. Cirik, K. Rikkinen, Y. Rong and T. Ratnarajah, "A subcarrier and power allocation algorithm for OFDMA full-duplex systems," European Conference on Networks and Communications (EuCNC'2015), Paris, France, June 29-July 2, 2015.