This paper proposes time-reversal based power division multiple access (TRPDMA) to enhance achievable sum rate (ASR) in dense multi-path environment. In TRPDMA, time-reversal (TR) introduces spatial focusing effect which provides a robustness of transmission using channel reciprocity. A mathematical approach is used to derive channel model of the proposed TRPDMA and calculate a closed-form of ASR. As performance metrics, ASR, ergodic ASR (EASR), and complexity are evaluated to compare with non-orthogonal multiple access (NOMA) and time-reversal division multiple access (TRDMA). The proposed TRPDMA outperforms than NOMA in both ASR and EASR while TRDMA in both ASR, ESAR and computational complexity.