Improper Signaling vs. Time-Sharing: Two Concepts for Boosting the Data Rates in Interference Channels


So-called improper complex transmit signals have been shown to be beneficial in the Gaussian interference channel (under the assumptions that all input signals are Gaussian and that interference is treated as noise), i.e., they can lead to a larger region of achievable rates than conventional proper signals [1]. This observation remains true if it is allowed to average the per-user rates over several transmit strategies that are applied one after another, which is often referred to as time-sharing. However, for the special case of a one-sided interference channel, it has recently been shown that an even larger rate region can be achieved without employing improper signals if we interpret time-sharing in a more general way and average not only the rates, but also the transmit powers over several transmit strategies [2].

The aim of this thesis is to study whether the same effect occurs in a general interference channel scenario where two users mutually disturb each other. This question should be investigated both analytically and numerically. The analytical derivations will be based, amongst others, on Lagrange duality theory. The numerical simulations can be implemented in MATLAB.

Related Literature

[1] Y. Zeng, C. M. Yetis, E. Gunawan, Y. L. Guan, and R. Zhang, “Transmit optimization with improper Gaussian signaling for interference channels,” IEEE Trans. Signal Process., vol. 61, no. 11, pp. 2899–2913, Jun. 2013.
[2] C. Hellings and W. Utschick, “Improper signaling versus time-sharing in the SISO Z-interference channel,” IEEE Commun. Lett., vol. 21, no. 11, pp. 2432–2435, Nov. 2017.



Christoph Hellings

Start date