Reconfigurable intelligent surfaces (RISs) represent a new technology that can shape the radio wave propagation and thus offers great variety of possible performance implementation gains. Motivated by this, we investigate achievable sum-rate optimization in broadcast channel (BC) presence RISs. We solve this problem exploiting well-known duality between Gaussian multiple-input multiple-output (...

We derive a new achievable rate region for the problem of communicating over a multiple access channel with states. Our coding technique is based on the ensemble of nested coset codes and the technique of typicality decoding. Exploiting structure in this ensemble, we analyze a more efficient decoding strategy to improve upon the rate region achievable using unstructured codes. We identify examp...

In this paper, our objective is maximizing total sum-rate subject to power constraints on total relay transmit power or individual relay powers, for amplify-and-forward single-antenna relay-based wireless communication networks. We derive a closed-form solution for the total power constraint optimization problem and show that the individual relay power constraints optimization problem is a quad...

The achievable rate of an Opportunistic NonOrthogonal Multiple Access (O-NOMA) based Cooperative Relaying System (CRS) with Channel State Information (CSI) available at the transmitter end is analyzed under Rician fading channels. It is shown that, O-NOMA-based CRS achieves a better achievable rate than Conventional-NOMA-based CRS and results are verified through Monte Carlo simulations. Keywor...