required accuracy for the adaptation signal to properly suppress the interference while keeping the degradation of the receiver Symbol Error Rate (SER) negligible. To provide the required accuracy, we propose a closed-loop method to dynamically adapt the path model such that the power of the residual interference at the output of the NIS is minimized. This method uses the baseband interference as a reference in order to combine simplicity with high accuracy and high speed. Our analysis and simulations show that the optimal adaptation signal can be estimated with sufficient accuracy, such that the interference is strongly suppressed while a SER close to that of an exactly linear receiver is achieved.
In Chapters 3 and 4, idealized models of the NIS and adaptation circuits are used to analyze the performance afforded by the NIS. In Chapter 5, we present experimental results of a multimode transceiver test bed that uses the mixed- signal integrated NIS circuit designed in [17]. The main circuit imperfections that limit the NIS performance are identified. Simple imperfection models are described that explain the experimental results. Based on these models, the NIS adaptation method is extended with simple digital compensation and calibration techniques that unlock the full interference suppression potential of the NIS circuit. Furthermore, a low-complexity digital compensation method is proposed for the CM distortion that is caused by the imperfections. Successful operation of the test bed suggests that the NIS approach is practical and attractive for multimode transceivers.
Concluding remarks and suggestions for future work are collected in Chapter 6. The analysis, simulation and experimental results in this thesis show that the NIS can achieve substantial interference suppression at attractive complexity and power dissipation, and that the residual distortion products can be digitally compensated with a low complexity. Both fundamental and practical limitations of the proposed approach are identified, and directions for future improvements are sketched.
1.6
Publications
The research work of this thesis resulted in the following publications.
1.6.1
Journal publications
H. Habibi, E.J.G. Janssen, Wu Yan, D. Milosevic, P.G.M. Baltus, J.W.M. Bergmans, ”Experimental evaluation of an Adaptive Nonlinear Interference Suppressor for Multimode Transceivers”, To be published in IEEE Journal on Emerging and Selected Topics in Circuits and Systems, Dec. 2013.
H. Habibi, E.J.G. Janssen, Wu Yan, P.G.M. Baltus, J.W.M. Bergmans, ”Closed- loop Adaptation of a Nonlinear Interference Suppressor for multimode Transceivers”, Submitted toIEEE Transaction on Vehicular Technology.
H. Habibi, E.J.G. Janssen, Wu Yan, P.G.M. Baltus, J.W.M. Bergmans, ”Sys- tem Study on Nonlinear Suppression of Varying-Envelope Local Interference in Multimode Transceivers”, Submitted to International Journal of Electronics and Communications.
H. Habibi, E.J.G. Janssen, Wu Yan, J.W.M. Bergmans, ”Digital Compensation of Cross-Modulation Distortion in Multimode Transceivers”IET communication, pp. 1724-1733, Aug. 2012.
1.6.2
Conference proceedings
H. Habibi, P.E. Ling, E.J.G. Janssen, Wu Yan, J.W.M. Bergmans, P.G.M. Bal- tus, ”Adaptive nonlinear interference suppressor for cognitive radio applications”,
Proceedings of Workshop on Cognitive Radio, Kista, Sweden, June, 2013.
H. Habibi, E.J.G. Janssen, Wu Yan, D. Milosevic, J.W.M. Bergmans, P.G.M. Baltus, ”Suppression of Constant Modulus Interference in Multimode Transceivers Using an Adaptive Nonlinear Circuit”. Proceedings of NASA/ESA Conference on Adaptive Hardware and Systems (AHS-2013), Turin, Italy June, 2013.
H. Habibi, E.J.G. Janssen, Wu Yan, P.G.M. Baltus, J.W.M. Bergmans, ”Non- linear Interference Suppressor for Varying-Envelope Local Interference in multi- mode transceivers”. Proceedings of 34th Symposium on Information Theory in the Benelux, Leuven, Belgium, May, 2013.
H. Habibi, E.J.G. Janssen, Wu Yan, P.G.M. Baltus, J.W.M. Bergmans, ”Closed- loop Adaptation of a Nonlinear Interference Suppressor for Local Interference in Multimode Transceivers”. Proceedings of 34th Symposium on Information Theory in the Benelux, Leuven, Belgium, May, 2013.
H. Habibi, E.J.G. Janssen, Wu Yan, J.W.M. Bergmans, P.G.M. Baltus, ”Suppres- sion of constant modulus interference in multimode transceivers by closed-loop tuning of a nonlinear circuit”. Proceedings of IEEE 75th Vehicular Technology Conference, Yokohama, Japan, May, 2012.
H. Habibi, E.J.G. Janssen, Wu Yan, J.W.M. Bergmans, ”Digital Compensation of Cross-Modulation Distortion in Multimode Transceivers”. Proceedings of IEEE 75th Vehicular Technology Conference, Yokohama, Japan, May, 2012.
1.6 Publications 17
E.J.G. Janssen, H. Habibi, D. Milosevic, P.G.M. Baltus and A.H.M van Roermund, ”Smart Self-Interference Suppression by Exploiting a Nonlinearity,” Invited paper in 22nd Workshop on Advances in Analog Circuit Design (AACD), Grenoble, France, April, 2013.
E.J.G. Janssen, H. Habibi, D. Milosevic, P.G.M. Baltus, A.H.M. van Roermund, ”Frequency-independent smart interference suppression for multi-standard transceivers”, Proceedings of the 42st European Microwave Conference (EuMC), Amsterdam, The Netherlands, November, 2012.
E.J.G. Janssen, H. Habibi, D. Milosevic, P.G.M. Baltus, A.H.M. van Roermund, ”Digital hardware resources for steering a nonlinear interference suppressor”. Pro- ceedings of the 19th International Conference Mixed Design of Integrated Circuits and Systems (MIXDES), Warsaw, Poland, May 2012.
E.J.G. Janssen, H. Habibi, D. Milosevic, P.G.M. Baltus, ”Modeling and Analysis of Nonlinearities and Bandwidth Limitations in RF Receivers”. Proceeding of IEEE International Symposium on Circuits and Systems (ISCAS), Rio de Janeiro, Brazil, May, 2011.