In this paper. we aim to maximize the sum rate of a full-duplex cognitive femtocell network (FDCFN) as well as guaranteeing the quality of service (QoS) of users in the form of a required signal to interference plus noise ratios (SINR). We first consider the case of a pair of channels. and develop optimum-achieving power control solutions. https://lecoureures.shop/product-category/triathlon-femme-wetsuits/