Ultra-wideband impulse radio (UWB-IR) has demonstrated strong advantages in the short range sensor networks in terms of low power, data rate scalability and low complexity implementation. This is why it was included in recently adopted IEEE 802.15.6 standard for wireless body area networks (BAN) as physical layer. In this paper, a hybrid architecture combining coherent and non-coherent receivers is proposed. Specific digital algorithms taking advantages of each radio front-end have been developed for 802.15.6 UWB-IR. Simulation reveals that the proposed architecture can achieve a packet error rate less than 10% for all IEEE 802.15.6 standard channel models and bit error rate less then 10-4 when considering the uniformity of bits errors.