This paper deals with the joint subcarrier and power allocation problem in a downlink multi-user orthogonal frequency division multiplexing system subject to user delay and minimum rate quality-of-service (QoS) requirements over a frequency-selective multi-copyright fading channel. We aim to maximize the utility-pricing function. formulated as the difference between the achieved spect... https://macorners.shop/product-category/2d-crystal-photo/