Embodiments herein relate to a method performed by a network node for handling a received signal in a communication network. The network node distributes a first number of inputs of a demodulated signal to a first processing core of at least two processing cores and a second number of inputs of the demodulated signal to a second processing core of the at least two processing cores. The network node further decodes the first number of inputs of the demodulated signal by a first message passing within the first processing core, and decodes the second number of inputs of the demodulated signal by a second message passing within the second processing core. The network node further decodes the demodulated signal by performing a third message passing between the different processing cores over a bus that is performed according to a set schedule.