Thank you for the clear presentation. My question is, you mentioned that IRS is not practical and difficult to acquire, so, how is your proposed IMI overcome this difficulty?
Thank you for your qustion. Firstly, the passive reflections of all reflecting elements at each IRS need to be properly designed to achieve cooperative signal focusing and/or interference cancellation in consideration of optimizing their end-to-end communications over the reconfigured wireless channels by IRSs.
In this study, In order to reduce interference from other OAM modes, the IMI cancellation uses a linear filter based on minimum mean square error(MMSE) that minimizes the squared error between the real transmission line and the estimated model as transmission line estimation when noise power is considered. This enables compensation of relatively small distortions, and stable characteristics can be obtained with a small amount of computation.
In this simulations are performed assuming perfect CSI, however in real network, it is practically difficult task to acquire the channel state information (CSI) between IRS and users that is essential to the aforementioned IRS reflection optimization, considering that IRS has a large number of reflecting elements and thus associated channel coefficients to be estimated. In future work, we need to consider imperfect CSI.
