Improved multiple access resource allocation in visible light communication systems

2018 ◽  
Vol 424 ◽  
pp. 98-102 ◽  
Author(s):  
Cobi Biton ◽  
Shlomi Arnon

Paper Discrete multi-tone (DMT) adjustment is accepted to be a accomplished single-transmitter arrangement for apparent ablaze correspondence. Be that as it may, the appliance of this action in a abundant transmitter action requires acute subcarrier and ability administration agreement so as to corruption the best accommodation of spatial altered transmitter different variety. Spatial reclaim of the subcarriers aural the afterimage of impedance and ability requirements expands the capability of abundant access (MA) DMT correspondence. In this paper, we adduce a adding that oversees obstruction accountable subcarrier reclaim amid assorted transmitters and ability redistribution amid assorted subcarriers in a heuristic way. The adding reenactment demonstrates an accessory in the accustomed bitrate as assorted and a acceptable DMT technique. Besides, the activity of the proposed MA-DMT artifice increments with the abundance of clients


Photonics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 85 ◽  
Author(s):  
Arslan Khalid ◽  
Hafiz Muhammad Asif ◽  
Konstantin I. Kostromitin ◽  
Sattam Al-Otaibi ◽  
Kazi Mohammed Saidul Huq ◽  
...  

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.


2019 ◽  
Vol 23 (8) ◽  
pp. 1365-1368 ◽  
Author(s):  
Zanib Tahira ◽  
Hafiz M. Asif ◽  
Asim Ali Khan ◽  
Sobia Baig ◽  
Shahid Mumtaz ◽  
...  

Author(s):  
Mouad Addad ◽  
Ali Djebbari

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.


2017 ◽  
Vol 16 (10) ◽  
pp. 6350-6364 ◽  
Author(s):  
Hanaa Marshoud ◽  
Paschalis C. Sofotasios ◽  
Sami Muhaidat ◽  
George K. Karagiannidis ◽  
Bayan S. Sharif

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