Rate-Power-Interference Optimization in Underlay OFDMA CRNs with Imperfect CSI

Achieving higher transmission rate while reducing transmission power and induced interference on neighboring receivers is deemed necessary for the advancement of future generation networks and is particularly challenging, since these directions could be conflicting in nature. This letter adopts a multiobjective optimization (MOOP) approach to settle the tradeoffs between these three conflicting objectives in orthogonal frequency-division multiple access-based cognitive radio networks. Besides, unlike most of the work in the literature that studied the imperfect channel side information (CSI) of the link between the secondary transmitter and the primary receiver to evaluate ergodic capacity, the MOOP formulation considers the imperfect CSI of cross links between secondary and primary, which makes the formulated MOOP difficult to solve, since traditional water-filling-in-time solution does not directly apply to this problem. Hence, to solve this MOOP, a dummy power allocation is first used, and then obtained MOOP is solved by using a weighted Tchebycheff method.