Effect of Estimation Timing Error on Pre-TDE for Narrowband Uplink NOMA

For realizing narrowband IoT such as sensor networks, we investigate narrowband uplink non-orthogonal multiple access (NOMA), which has high spectrum efficiency. In the narrowband uplink NOMA system, multiple access interference (MAI) occurs because the signals from non-orthogonal nodes propagate different time selective fading channels. In this situation, time-domain pre-equalization (Pre-TDE) can suppress MAI. Since narrowband communication has a small data rate and long data communication time, the effect of estimation timing error Δt on pre-TDE is large. In this paper, to clarify the effect of fading on narrowband uplink NOMA we evaluated the effect of the estimation timing error. As a result of link-level simulation considering the estimation timing error, we verified that bit error rate (BER) is less than 10
^-3
when the estimation timing error is within 1.5ms from the channel estimation value.