Power allocation method in cognition orthogonal frequency division multiple access (OFDMA) system based on proportional fairness and interference constraints

The invention discloses a power allocation method in a cognition orthogonal frequency division multiple access (OFDMA) system based on proportional fairness and interference constraints, comprising the following steps: firstly carrying out power allocation among cognitive users in accordance with proportional fairness factors, total power constraints and permanent speed values; then using a quick water injection method to carry out carrier power allocation by each cognitive user; if the carrier power of each cognitive user does not exceed a power constraint value, ending an algorithm, and otherwise, modifying allocated power of a carrier exceeding the power constraint to be the power constraint value; calculating the speed of the carrier and adding the speed to the permanent speed value of the user; eliminating the carrier from the carrier set of the user; and if the carrier set of each cognitive user is a null set, ending the algorithm, otherwise, subtracting the allocated power constraint value from a total