Abstract--Dynamic spectrum access (DSA) supporting opportunistic transmission without extra spectrum bandwidth is attractive for future wireless communication. To facilitate such DSA system, a power-efficient (green) communication processor is needed to support extremely high speed operation on a powerlimited mobile device. Traditional general-purpose and digital signal processors are unable to simultaneously satisfy the processing speed and power efficiency for DSA systems. By exploiting critical parallelism and data exchange patterns based on communication algorithms inside a green processor, we successfully develop green SDR based communications processor for DSA that can be reconfigured to multiple system operation. We verify this novel architecture in TSMC 0.13