⁠Evaluation of Backscatter Communication Strategies in 5G-Enabled Ambient IoT Networks

Ambient Backscatter Communication allows low-power IoT devices to transmit data by reflecting radio-frequency signals already present in the environment. Cellular networks are attractive sources because they combine wide-area coverage with standardized physical-layer signals. This thesis compares two 5G New Radio configurations. In the first, the Base Station (BS) illuminates the Backscatter Device (BD) with the downlink Synchronization Signal Block (SSB) and a User Equipment (UE) receives. In the second, a nearby UE illuminates the BD with uplink Sounding Reference Signals (SRS) and the BS receives. A common analytical and simulation framework models the forward, backscatter and direct paths, using 3GPP TR 38.901 models for the InH, UMi and UMa scenarios and free-space path loss for the UE–BD link, and includes shadow fading, device losses, residual direct-component interference, thermal noise, FSK detection and multi-device transmissions. Reliable detection is limited to a few metres from the UE in both configurations. Under LOS conditions both are limited by the residual direct component, so transmit power does not affect the signal-to-interference ratio: with 45 dB of direct-component rejection, a BER of 10⁻³ is reached up to about 2.6–3.7 m from the UE, with a slightly lower BER for SRS. Under NLOS conditions SRS is noise-limited and does not reach the target, while SSB, favoured by the higher BS power, reaches it up to about 0.5–2.8 m. The same shift towards SSB occurs as the UE–BS distance increases. With several active devices, the message of the strongest one can still be recovered, with a probability that depends on their number and spatial distribution. The results identify the propagation and deployment conditions under which each configuration is more favourable.