Time Multiplexed Optical-OFDMA for Uplink Transmission in LiFi-based IoT Networks

Abstract

The transfer of data from multiple internet of
things (IoT) devices requires the use of a robust and efficient
multiple access (MA) solution. This paper considers the orthogonal frequency division MA (OFDMA) technique for the
light-fidelity (LiFi)-based IoT uplink using infrared to transmit
data from multiple mobile users to a fixed access point. The
conventional schemes based on orthogonal frequency allocate
distinct subcarriers to each user sharing the same time slot.
We consider a new approach by allocating distinct time slots
to a group of OFDMA users. Taking into account realistic
opto-electronic components, we study the performance of the
conventional and proposed optical-OFDMA schemes. We show
that asymmetrically clipped optical-OFDMA signaling scheme
outperforms direct current biased signaling in terms of electrical power efficiency. Focusing on the asymmetrically clipped
signaling, we demonstrate the robustness of our proposed time
multiplexed optical-OFDMA scheme against MA interference
caused by signal clipping. We also show the advantages of our
scheme in reducing computational complexity by a factor of 2
compared to the conventional optical-OFDMA schemes.