Investigations of noncoherent OOK based schemes with soft and hard decisions for WSNs

On-off keying (OOK) with noncoherent detection currently turns out to be very attractive for ultra-low power design for wireless sensor networks (WSNs) because of its simplicity. This paper investigates the capacity behavior of noncoherent OOK over AWGN channels in the low signal-to-noise ratio regime to demonstrate that energy autonomy can be achieved for WSNs. Our investigations show that noncoherent OOK modulation both with soft and hard decisions can achieve the Shannon limit for extremely asymmetric ´on-off´ distributions. We also determine the wideband slope for both models here. According to our capacity study, pulse-position modulation (PPM) is suggested as channel coding scheme combined with OOK signaling, for both the soft and the hard case. A recommendation for a specific Reed-Solomon code in combination with PPM is provided based on performance evaluations.