Generalized Degrees of Freedom of the Symmetric $K$ User Interference Channel Under Finite Precision CSIT

Abstract

The generalized degrees of freedom (GDoF) characterization of the symmetric K-user interference channel is obtained under finite precision channel state information at the transmitters (CSIT). The symmetric setting is where each cross channel is capable of carrying α degrees of freedom (DoF) while each direct channel is capable of carrying 1 DoF. Remarkably, under finite precision CSIT the symmetric K-user interference channel loses all the GDoF benefits of interference alignment. The GDoF per user diminish with the number of users everywhere except in the very strong (optimal for every receiver to decode all messages) and very weak (optimal to treat all interference as noise) interference regimes. The result stands in sharp contrast to prior work on the symmetric setting under perfect CSIT, where the GDoF per user remain undiminished due to interference alignment. The result also stands in contrast to prior work on a subclass of asymmetric settings under finite precision CSIT, i.e., the topological interference management problem, where interference alignment plays a crucial role and provides substantial GDoF benefits.

Multi-antenna cache-aided channels

“…is the signal received at user k, h k ∈ C is the channel coefficient of user k, and z k ∼ CN (0, 1) represents the Gaussian noise at user k. Under the Generalised Degrees of Freedom (GDoF) framework [49]- [52], the received signal can be re-written in its more GDoF-friendly form as follows…”

Improving CSI Prediction Accuracy with Deep Echo State Networks in 5G Networks

“…the i-th update is given by (6), in which W (1) and W (i) are the input and the inner weight matrix, respectively. More in depth, W (i) represents the weight matrix for the connection of the (i − 1)-th inner layer to the i-th.…”

“…Under these circumstances, the channel state information (CSI) represents one of the most important concepts in the wireless networks [ 2 , 3 , 4 ], providing a performance metric for the quality of the radio channel. The CSI describes the physical layer parameters arranged for wireless communication systems [ 2 ], being crucial in many decision making areas such as radio resource allocation [ 5 ], interference management [ 6 ], and so on. Consequently, an accurate value of the CSI plays a role of paramount importance in a wide range of practical applications, while inaccuracy on the CSI prediction value leads inevitably to substantial degradation on communication effectiveness.…”