Error Rate Analysis of NOMA inspired DF Relay System with Imperfect SIC in IoT Network

In IoT network the usage of short packets poses a challenge to reliable and secure transmissions due to low complexity limitations and large connection demand. To improve the spectrum usage and system performance, this research study investigates the cooperative NOMA (C-NOMA) downlink short packet transmission scheme in IoT network, where the direct link is available to both the IoT users. This model includes a source, strong user (S
U
), weak user (W
U
) and a decode-and-forward (DF) relay. Based on NOMA transmission scheme, packets from source to S
U
is transmitted via direct link and W
U
via cooperative relay link where both perfect and imperfect successive interference cancellation (SIC) scenarios are considered. Using linear estimates on block error rate (BLER), this research study theoretically compute the average BLER of both the IoT users. Moreover, the asymptotic average BLER analysis is also presented at high signal-to-noise ratios. The derived analytical BLER collides with the simulated result, as proved by numerical analysis. Furthermore, in high SNR zone when the average BLER does not approaches to unity, power allocation factors become insignificant for both the IoT users.