Design Concepts and Performance Analysis of Multicarrier CDMA for Indoor Visible Light Communications

Shoreh, Morteza H.; Fallahpour, Ahmad; Salehi, Jawad A.

doi:10.1364/jocn.7.000554

Cited by 46 publications

(22 citation statements)

References 13 publications

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“…M, Maximum number of active users N, error threshold P e th , code reallocation interval T Output: Code assignment messages 1: design an OCDMA system with N users, M wavelengths and error threshold P e th using formulation (6) and name obtained code length, code weight and crosscorrelation L, W and λ; 2: for i = 1, · · · , N do 3: design an OCDMA system with i users, M wavelengths, code length L and error threshold P e th using formulation (7) and name obtained code weight and cross-correlation W i and λ i ; 4: end for 5: n ←− N; 6: choose code book (L,W n , λ n ); 7: send code assignment messages; 8: T cr ←− time() + T; 9: while 1 do 10: if a user activation message is received then 11: n ←− n + 1; 12: else if a user deactivation message is received then 13: n ←− n − 1; 14: end if 15: if time() T cr then 16: choose code book (L,W n , λ n ); 17: send code assignment messages; 18: T cr ←− time() + T; 19: end if 20: end while For example when L max = 4000, W max = 100 and λ max = 5, the complexity gain G com is more than 10 4 which means that Alg. 1 is 10 4 times faster than its brute force search counterpart.…”

Section: Input: User Activity Information Number Of Wavelengthmentioning

confidence: 99%

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Analysis and Design of Adaptive OCDMA Passive Optical Networks

Hadi

Pakravan

2017

J. Lightwave Technol.

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OCDMA systems can support multiple classes of service by differentiating code parameters, power level and diversity order. In this paper, we analyze BER performance of a multi-class 1D/2D OCDMA system and propose a new approximation method that can be used to generate accurate estimation of system BER using a simple mathematical form. The proposed approximation provides insight into proper system level analysis, system level design and sensitivity of system performance to the factors such as code parameters, power level and diversity order. Considering code design, code cardinality and system performance constraints, two design problems are defined and their optimal solutions are provided. We then propose an adaptive OCDMA-PON that adaptively shares unused resources of inactive users among active ones to improve upstream system performance. Using the approximated BER expression and defined design problems, two adaptive code allocation algorithms for the adaptive OCDMA-PON are presented and their performances are evaluated by simulation. Simulation results show that the adaptive code allocation algorithms can increase average transmission rate or decrease average optical power consumption of ONUs for dynamic traffic patterns. According to the simulation results, for an adaptive OCDMA-PON with BER value of 1e-7 and user activity probability of 0.5, transmission rate (optical power consumption) can be increased (decreased) by a factor of 2.25 (0.27) compared to fixed code assignment.Comment: 11 pages, 11 figure

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Section: Input: User Activity Information Number Of Wavelengthmentioning

confidence: 99%

“…Furthermore, some researchers have concentrated on designing new code families and efficient coding/decoding structures for OCDMA systems to reduce design complexity and increase system capabilities [10]- [14]. Performance analysis of different OCDMA-based systems is another attractive research topic [1]- [4], [6], [15].…”

Section: Introductionmentioning

confidence: 99%

Analysis and Design of Adaptive OCDMA Passive Optical Networks

Hadi

Pakravan

2017

J. Lightwave Technol.

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“…Where nd is the entire number of variables, Uq and Lq are the upper and the lower limits of the q th variables (q=1,2,…,nd), correspondingly and PC is the position constant number within [0,2]. In order to progress the enactment of the optimization issue and to accelerate the convergence property, the crossover and also the mutation procedure of GA algorithm is assimilated with KHA.…”

Section: Step 6: Position Updatementioning

confidence: 99%

“…The developing remote request alongside deficiencies in cell limit soon, different options, for example, visible light communication (VLC), have gotten genuine consideration as promising arrangements. Besides, the data transfer capacity impediments on the unlicensed radio recurrence (RF) range don't by any methods close the speed gap between RF remote and optical fiber systems [2]. The creating administrations require higher information rates from future cellular wireless communication.…”

Section: Introductionmentioning

confidence: 99%

Performance of MIMO MC-CDMA for STBC Communication System Using OKHA Based Optimal Channel Estimation

Sreesudha¹,

Malleswari²

2017

IJIES

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Abstract:In the late years, MIMO MC-CDMA approach has been proposed in order to expand framework capacity over frequency-selective wireless channels. The key component of MIMO MC-CDMA is the capacity of abusing diversity jointly in time, frequency and in the space domain. In this work, we implement an efficient multi-user STBC MC-CDMA transmission System Based on Minimum Conditional BER Criterion and Oppositional krill herd algorithm (OKHA) assisted channel estimation. The multiuser MC-CDMA system using Alamouti's Space-Time Block coding for encoding the transmitting sequence. The estimation of Channel State Information (CSI) is optimally selected using OKHA. Normally, KHA is a natural-inspired metaheuristic algorithm which mimics the herding behavior of ocean krill individual. To improve the convergence speed and accuracy of the basic KHA algorithm, in this proposed work we combine KHA with oppositional based learning (OBL). The experimental results are conducted for the different algorithm based on BER, SER, and spectral efficiency. The simulation results show that the proposed algorithm is properly reducing the BER, SER and properly increase the spectral efficiency value compare to other techniques.

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“…For broadcasting information using VLC, many different schemes are proposed in literature such as expurgated pulse position modulation [1], adaptive modulation based on power control [2] and optical code division multiple access (OCDMA) [3]. All these techniques require a central unit to coordinate the transmission of the LEDs.…”

Section: Introductionmentioning

confidence: 99%

Minimal Noise Variance Decoder for Uncoordinated Multiple Access in VLC

Saed

Gorce

et al. 2017

2017 IEEE 85th Vehicular Technology Conference (VTC Spring)

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Abstract-In a visible light communications system (VLC), light sources are responsible for both illumination, communications and positioning. These light sources inevitably interfere each others at the receiver. To retain the appealing advantage that VLC systems can reuse existing lighting infrastructure, using an extra network to control or synchronize the light sources should be avoided. This paper proposes an uncoordinated multiple access scheme for VLC systems with positioning capability. The proposed scheme does not require a central unit to coordinate the transmission of the transmitters. Transmitters can be asynchronous with one another and with the receiver. Each transmitter is allocated a unique codeword with L chips for a system with up totransmitters where L is prime. Due to the linear growth in complexity with respect to number of transmitters, our proposed scheme is feasible for systems with large numbers of transmitters. Our novel decoder can minimize the effect of additive Gaussian noise at the receiver side. Simulation results show that the proposed decoder outperforms zero-forcing decoder.

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Design Concepts and Performance Analysis of Multicarrier CDMA for Indoor Visible Light Communications

Cited by 46 publications

References 13 publications

Analysis and Design of Adaptive OCDMA Passive Optical Networks

Analysis and Design of Adaptive OCDMA Passive Optical Networks

Performance of MIMO MC-CDMA for STBC Communication System Using OKHA Based Optimal Channel Estimation

Minimal Noise Variance Decoder for Uncoordinated Multiple Access in VLC

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