  This paper reports an implementation of the PHY specifications of the IEEE
802.15.4 standard for the frequency band 868 915 MHz on a Software Defined
Radio (SDR) platform. This standard is defined for low power, low data rate and
low cost wireless networks. These specifications are used by the Zigbee
technology for various applications such as home automation, industry
monitoring or medical surveillance. Several hardware PHY 868/915 MHz band IEEE
802.15.4 transceiver implementations have been already reported on ASIC and FPG
[1] [2]. SDR offers one possibility to realize a transceiver with high
flexibility and reconfigurability [3]. The whole transmitter and receiver chain
has been defined in software using the GNU Radio software project [4] and the
USRP (Universal Software Radio Peripheral) platform from Ettus Research [5].
Two new blocks have been added to the GNU Radio project, one for the Direct
Sequence Spread Spectrum and the second for the reconstruction of the packets.
The experimentations have been performed in a noisy environment and the PER,
BER and SNR have been computed. The obtained results are coherent with what can
be expected from the theory.
