In this paper, the authors propose a Transmission Power Control (TPC) algorithm for power management, energy-efficiency and delay-aware communication in wireless sensor network. Transmission Power Control Algorithm not only prolongs the lifetime of sensor nodes by saving the energy consumption but enhance throughput and performance of packet delivery ratio. Apart from that, it can also reduce the interference between transmitting nodes. According to this algorithm, each node utilizes the RSSI (Received Signal Strength Indicator) value to determine the appropriate transmission power for its neighbors.