Throughput, delay and bandwidth efficiency of IEEE 802.15.4a using CSS PHY

The IEEE 802.15.4 standard is a short range wireless technology. As a revision to this standard, IEEE 802.15.4a introduces new options for PHY (physical layer) to enable ranging. In this paper, we investigate the theoretical maximum throughput and minimum delay of the un-slotted version of 802.15.4a using CSS (Chirp Spread Spectrum) PHY. The throughput and delay limits are derived for different frequency bands and data rates along with the formulae. Moreover, we calculate the bandwidth efficiency for both the standards. The comparative analysis concludes that the performance of 802.15.4a surpasses 802.15.4 in terms of throughput and delay.