Turbo codes are one of the best coding schemes for error correction because of their highest coding gain achievements. Number of iterations totally affects the turbo decoding process; it has an impact on the decoder performance, latency and power consumption. Dealing with battery-based devices requires paying attention to the battery life-time, consumed power, and hence the importance of a power efficient designs. Adapting the number of iterations according to the channel state gives a power efficient design for the decoder as illustrated in this paper. Two Channel Estimators methods are proposed here, the first one depends on the calculation of the Pilot Error Rate (PER) and the other one calculates the Bit Error Rate (BER) over the decoder as an indicator for the channel state. There is a tradeoff between the two methods in the reliability, synchronization and latency.