Collaborative Transmitters Management for Multi‐user Indoor VLC Systems

Abstract

The main encounters face visible light communication (VLC) systems to provide high data rates for multiuser scenario are intersymbol interference (ISI) and cochannel interference (CCI). This work proposes delay adaptation technique (DAT) in conjunction with power adaptation technique (PAT) to improve the performance of the multiuser indoor VLC systems. The DAT is used to reduce the ISI while the PAT is utilized to reduce the CCI. To apply the DAT and PAT, each access point (AP) requires to share its information with the controller, which is responsible to manage the connection between user equipment (UEs) and APs. Therefore, each AP is given a control signal (an unmodulated unique tone signal). These control signals are utilized to set‐up the connection between APs and UEs (allocate each UE its best APs, which are APs that offer good connection links). Our proposed system performance is evaluated in a realistic room while considering the effect of diffuse reflections and CCI and using on‐off‐keying modulation. The results reveal that a remarkable improvement in the VLC system's performance with using DAT and PAD compared with the VLC system without using DAT and PAT.

Interference mitigation in multiuserWDM VLCsystems using differential receiver

“…The functions of these control signals are: (1) to identify (label) each Tx, (2) to assign the best Tx for each user and (3) to find the interference level that is introduced from interfering Txs. Control signals have proposed widely for many applications in VLC systems 13‐16 . In, 13 control signals were used with non‐orthogonal multiple access (NOMA) to obtain bidirectional connection in indoor VLC system.…”

“…In, 15 control signals were proposed to manage the handover in VLC systems. In, 16 control signals were proposed to attain power adaptation technique and delay adaptation technique in indoor VLC systems. Here, control signals with differential detector are used to cancel the interference between WDM channels for multiuser indoor VLC systems.…”

“…Control signals have proposed widely for many applications in VLC systems. [13][14][15][16] In, 13 control signals were used with non-orthogonal multiple access (NOMA) to obtain bidirectional connection in indoor VLC system. Reference 14 used control signals in multiuser VLC system to localize the best Tx for each user.…”

BER performance of MIMO based NOMA‐VLC system with imperfect SIC

“…For optimization of spectral efficiency, an adaptive OFDM based MIMO‐VLC system is presented in Reference 8. In Reference 9, delay adaptation technique (DAT) and power adaptation technique (PAT) are proposed to enhance the performance of multi‐user VLC system.…”