This paper addresses joint subcarrier pairing, dynamic subcarrier allocation and power allocation which satisfies user expected rate in OFDMA-based decode-and-forward relaying networks for which users have different expected rate. A mathematical model for minimizing difference between the achievable and expected rates is established. Three algorithms are proposed. First, a joint subcarrier pairing and dynamic subcarrier allocation algorithm (ERDSA) with average power allocation is used. Second, if the system resource is insufficient, a joint subcarrier pairing and dynamic subcarrier allocation algorithm (EERDSA) with proportionate reduction of user expected rate can be used. When the system power is evenly allocated, the data rates of the first and the second hops are mismatched. In this case, a joint subcarrier pairing, dynamic subcarrier allocation and power allocation algorithm (DJSPA) is used. Analyses show that ERDSA, EERDSA and DJSPA have low complexity, linearly proportional to the number of subcarriers. Simulation shows that the proposed schemes can satisfy user expected rate and reduce power consumption.