Code division multiple access based visible light communication in vehicle adaptive cruise control under emergency situation

2013 ◽  
Author(s):  
Shuying Xie ◽  
Chengjin Zhang
Keyword(s):  
Visible Light ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Adaptive Cruise Control ◽  
Emergency Situation ◽  
Visible Light Communication ◽  
Cruise Control ◽  
Code Division Multiple

scholarly journals Doubly Orthogonal Wavelet Packets for Multi-Users Indoor Visible Light Communication Systems

Photonics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 85 ◽  
Author(s):  
Arslan Khalid ◽  
Hafiz Muhammad Asif ◽  
Konstantin I. Kostromitin ◽  
Sattam Al-Otaibi ◽  
Kazi Mohammed Saidul Huq ◽  
...  
Keyword(s):  
Visible Light ◽  
Communication Systems ◽  
Multiple Access ◽  
Visible Light Communication ◽  
Wavelet Packets ◽  
Easy Access ◽  
Line Of Sight ◽  
Detection Scheme ◽  
Time Frequency ◽  
Code Division Multiple

Visible Light Communication (VLC) is a data communication technology that modulates the intensity of the light to transmit the information mostly by means of Light Emitting Diodes (LEDs). The data rate is mainly throttled by the limited bandwidth of the LEDs. To combat, Multi-carrier Code Division Multiple Access (MC-CDMA) is a favorable technique for achieving higher data rates along with reduced Inter-Symbol Interference (ISI) and easy access to multi-users at the cost of slightly reduced compromised spectral efficiency and Multiple Access Interference (MAI). In this article, a multi-user VLC system is designed using a Discrete Wavelet Transform (DWT) that eradicates the use of cyclic prefix due to the good orthogonality and time-frequency localization properties of wavelets. Moreover, the design also comprises suitable signature codes, which are generated by employing double orthogonality depending upon Walsh codes and Wavelet Packets. The proposed multi-user system is simulated in MATLAB software and its overall performance is assessed using line-of-sight (LoS) and non-line-of-sight (NLoS) configurations. Furthermore, two sub-optimum multi-users detection schemes such as zero forcing (ZF) and minimum-mean-square-error (MMSE) are also used at the receiver. The simulated results illustrate that the doubly orthogonal signature waveform-based DWT-MC-CDMA with MMSE detection scheme outperforms the Walsh code-based multi-user system.

scholarly journals A New Code Family for QS-CDMA Visible Light Communication Systems

2018 ◽  
Vol 3 ◽  
pp. 5-8 ◽  
Author(s):  
Mouad Addad ◽  
Ali Djebbari
Keyword(s):  
Visible Light ◽  
Communication Networks ◽  
Communication Systems ◽  
Multiple Access ◽  
Multipath Propagation ◽  
Multiple Access Interference ◽  
Visible Light Communication ◽  
Wireless Communication Networks ◽  
Strong Candidate ◽  
Code Division Multiple

Visible light communication (VLC) is a promising technology for wireless communication networks. Optical code division multiple access (OCDMA) is a strong candidate for VLC-based applications. The predominant source of bit error in OCDMA is the multiple access interference (MAI). To eliminate MAI in synchronous OCDMA, zero cross correlation (ZCC) codes have been proposed. However, synchronization problems and multipath propagation introduce relative non-zero time delays. Therefore, the zero correlation zone (ZCZ) concept was introduced. In this paper, we propose a new method for generating ZCC codes. The proposed construction can accommodate any number of users with flexible Hamming weight. The numerical results obtained show that the proposed codes significantly reduce MAI, compared to ZCC, as well as ZCZ codes.

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