In broadband communication systems, an analog-to-digital converter (ADC) with few-bit quantization is a promising component in a RF front-end to ensure higher sampling rate. To mitigate the nonlinear behavior in the few-bit ADC, a stochastic resonance (SR), which improves a symbol error rate (SER) in the presence of the noise, has been focused. The SER degrades in a high signal-to-noise ratio (SNR) region. In this paper, we introduce the addition of the intentional noise in the SR-based receiver. To add the intentional noise appropriately, we propose simple estimation methods for the channel noise-power in the receiver with the few-bit ADC. To obtain the closed-form for a error function, we employ a sigmoid approximation. Numerical examples show that the proposed receiver can estimate the noise-power in a specific range of SNR. Low SER can be achieved for higher SNR by the addition of the intentional noise.