Performance Analysis Indoor Visible Light Communication System

fundamental analysis for visible light communication system and an indoor visible light communication positioning system visible light communication system for outdoor
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Published Date:09-11-2017
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I. J. Computer Network and Information Security, 2017, 7, 11-19 Published Online July 2017 in MECS ( DOI: 10.5815/ijcnis.2017.07.02 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light Communication System Ram Sharma School of Engineering, The NorthCap University, Gurgaon, India E-mail: A. Charan Kumari School of Engineering, The NorthCap University, Gurgaon, India E-mail: Abstract—The LED (Light emitting diode) based lighting switching, high illumination white LEDs are likely to systems are gaining popularity for its dual use i.e. for enhance the performance of a VLC system in terms of energy efficient lighting systems as well as for indoor bandwidth parameters. Over the last few decades, a optical wireless communication systems. Although, qualitative progress has been witnessed towards Visible light spectrum has the capability to provide very innovating new wireless technologies. This also reflects large system bandwidth (in THz), yet these systems have the ever rising demand for voice, data and various other the limitation on account of limited modulation multimedia services with guaranteed quality of service bandwidth. Besides, Visible light communication (VLC) parameters (QOS) which are putting additional pressure systems also suffer due to multi-path propagation on the existing spectrum which is a scarce resource. The resulting in further depletion of system bandwidth due to Next Generation Wireless Network (NGWN) especially pulse broadening. Therefore, one of the deployment the indoor networks will have to be evolved with very objective of a visible light communication (VLC) system high data rates3. is to reduce the root mean square (RMS) delay parameter Presently, the demand for mobile and data services in besides minimizing the number of LEDs. Hence, the indoor communication domain is increasing performance analysis of two geometrical shape structures exponentially due to various multimedia applications. mainly rectangular and circular models are explored for The recent studies indicate that a substantial portion ubiquitous indoor coverage using hyper- heuristics (more than 70 percent) of wireless traffic originates evolutionary algorithm(HypEA) under spatial receiver indoors. This is usually catered through radio femtocells mobility. Therefore, it is possible to achieve lower RMS which are low-power, low-cost base stations (BSs). These delay spread and hence multi- fold increase in the overall cellular base stations are overlaid on the existing cellular system bandwidth without the use of complex system network and are generally user deployed. The femtocells techniques like OFDM- MIMO etc. improve the indoor capacity as well as the coverage mainly due to the frequency reuse within the range of Index Terms—Average outage area ratio, hyper-heuristic tens of meters4. An alternative solution to radio evolutionary algorithm, indoor VLC system, root mean frequency (RF) technique is VLC technology which has square delay, Signal to Noise Ratio. the potential of delivering greater data rate densities 2 (b/s/Hz/m )5. The main attraction of VLC technology is its spectrum which is available for free and is presently I. INTRODUCTION unregulated. Besides VLC can be used inside airplanes, hospitals, factories, mines, power plants, petrochemical Light emitting diodes (LEDs) are energy efficient, plants etc where the use of RF technology is prohibited. comparatively low cost and eco-friendly devices which Since lighting is an essential requirement for indoor are being used extensively for lighting systems in the illumination, therefore, no extra energy is required for indoor environment. LEDs have seen phenomenal growth information transmission except for a minimal additional in terms of technology enhancement resulting in power requirement for the driver circuitry for increased life span, high intensity and low power which communication. In this way, VLC is also capable of makes it very useful for indoor Visible light reducing the carbon footprint in the information and communication (VLC)system. Among various types of communication technology (ICT) industry resulting in the LEDs including PC-LEDs (Phosphorous converted energy efficient networks6. LEDs), organic LEDs, micro-chip LEDs (µ- LEDs), This may also be stated that vast unused spectrum may multichip LEDs, the 3 dB bandwidth of micro chip LEDs provide the necessary bandwidth to meet the ever- may go up to 450 MHz 1- 2. Thus, the use of fast growing demand for increased telecommunication traffic. Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 12 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light Communication System VLC can further help in establishing more secure such technical challenges have already been overcome in networks. There remain, of course, many challenges that RF technique after decades of research, Similarly, VLC is VLC systems are currently facing due to being a well poised to go along a similar but much-accelerated relatively new technology. There are issues that remain path. Hence there is no doubt that VLC will be able to from the inherent nonlinearity of LEDs, bandwidth provide ubiquitous communication network in future limitations, signal modulation aspects, multi-access as communication generations7. well as power delivery to the transceiver. However, since Fig.1. Proposed system Models The VLC communication system may employ various of various other system parameters by18. link topologies depending on the transmitters beam In literature, a different heuristic technique known as directionality and receivers field of view (FOV). For a hyper-heuristic evolutionary algorithm (HypEA) have mobile VLC system, the nondirected-LOS first proposed been suggested by 19 for dynamic assignment of radio by 8. For indoor VLC systems, the genetic evolutionary frequency channels. The HypEA approach 20 is algorithm was first implemented by 9- 10 to modify presented in Appendix A. Motivated by this approach and the optical intensity to analyze the signal to noise ratio the computing efficiency of the algorithm, we propose to (SNR) fluctuations. Further Particle swarm optimization implement HypEA technique to the proposed VLC (PSO) technique was used for LED deployment by 11. problem for two types of system models. System model 1 One of the most important advantages of a VLC system is is proposed to be a rectangular room and system model 2 its bandwidth reuse so as to achieve high spatial spectral is consisting of a circular room. The LEDs are placed on efficiency. The LEDs are capable of providing highly the rooftop. The system performance is analyzed and directional beams which make it possible to transmit the compared after the HypEA implementation for the two signal with lesser interference. Therefore, non-interfering system models to ensure receiver mobility mainly with links in close proximity could make it possible to achieve the following contributions, large data density 12 and spatial reuse of modulation bandwidth in adjacent communication cells 13-14. An  We analyze the average outage area ratio adaptive receiver technique has been suggested by 15 to defined as the average outage area ratio as the address a number of challenges posed by LED-based area where the receiver detects an error during indoor communication system especially the signal its movement to the total floor area of the room. distortion due to multipath propagation which limits the A comparison is thus made for the optimum system's bandwidth. Further, an Electro-optic Modulators deployment of LEDs for both the models. for low loss wide bandwidth capability for optical  The impact of LED semi-angle on the receiver communication system has been discussed by 16 mobility has been analyzed along with the including the optimization of a number of system number of LEDs required at various semi-angle parameters. An IR-based mobile system comprising a of LEDs. single IR source and a mobile receiver based on  The root mean square (RMS) delay is analyzed nondirected-LOS diffused topology was investigated for to assess the inter-symbol interference (ISI). its system performance by17 followed by its channel RMS delay at various semi-angle has also been capacity and BER estimation along with detailed analysis analyzed. It has been demonstrated that more Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light 13 Communication System directionality improves the RMS delay and Both the models thus represent the same area i.e. 25 hence the ISI is reduced. square meters. The height of the structures is considered as 3 meters for these models. Also, the receiver is mobile The rest of this paper is organized as follows. The on the x-y plane whose location is given as (x , y , c ). It o o h related work is presented in section II and the system is proposed to deploy N LEDs on the roof/ceiling at model in section III. The problem is formulated in section positions (x , y , c), where c = 3 meters and i ∈ (1, 2, i i IV. The results are analyzed in section V. Finally, the 3, ....N ). For rectangular shape, the placement conclusion is given in section VI. coordinates of LEDs are bound by the dimension such that 0 x 6.25 and 0 yi 4 . Accordingly, LED i positioning in the circular shape is bound within the II. RELATED WORK desired circle boundary of requisite radius as given above. Among all the modulation techniques based on 4G/5G Indoor VLC (380 – 780 nm) can be considered intensity modulation with direct detection (IM/DD), on- as a relatively new technology proposed as an alternative off keying (OOK) is the most appropriate, simple and to indoor IR (780-950 nm) access technologies21,22 widely accepted modulation scheme used in optical offering a number of functionalities. In addition to wireless communication (OWC) system because of its illumination, VLC offers data communication and indoor ease of hardware implementation, simple receiver design, localization (where current RF based global positioning bandwidth efficiency and cost- effectiveness 32. systems (GPS) offers limited or no coverage in the indoor and underground environment using the existing white Table 1. Comparison of Average Outage Area Ratio ’R’ and the o light emitting diodes (LED) based lighting fixtures23. Number of LEDs at semi- angle (ϕ = 60 ) 1/2 These features have made the emerging field of indoor Sl. No. Value of 'R' Value of 'R' short-range VLCs very attractive to the worldwide No. of LEDs (Rectangular Model) (circular Model) research community, through bodies such as the VLC 1 10 1.0000 1.0000 consortium (more than 20 organizations) in Japan in 2003 24, the Wireless World Research Forum14, the 2 20 1.0000 1.0000 European OMEGA project 25, IEEE standardization 3 30 1.0000 1.0000 body 26, 27, and UK research council funded ultra- 4 40 0.7684 1.0000 parallel VLC 28. The current IEEE VLC standard approved in 2011 5 50 0.6692 1.0000 supports up to 96 Mbps. A Task Group recently revived 6 60 0.5616 1.0000 the work in IEEE 802.15.7 and is working on an enhanced VLC physical layer based on OFDM to enable 7 70 0.4447 0.5246 peak data rates at Gbps. It is also planned that this 8 80 0.3089 0.4453 standard will support optical camera communication (OCC) where Smartphone cameras are used for reception 9 90 0.1756 0.3768 in low data rate applications29. Standardization is 10 100 0.0576 0.2571 expected to be finalized by the end of 2017. With the 11 110 0.0066 0.0000 emergence of Indium Gallium Nitride (InGaN) technology it has been possible to manufacture efficient 12 120 0.0000 0.0000 white LEDs in a number ways: (a) combining red, green, blue light sources (RGB) offer typically 20 MHz of The binary information sequence can be mapped Existing off-the-shelf LEDs have a limited bandwidth (up directly to the sequence of light pulses at the transmitter to 50 MHz for incoherent IR, 10 MHz for WPLED and according to the rule: if the information bit is 1, transmit 400 kHz for organic LEDs). Using commercial high a laser pulse; if it is 0, transmit nothing , Therefore, there power LEDs, VLC systems can provide 200+ Mbps data is a one-to-one correspondence between 1’s in the data- rates. In VLCs the most popular way to increase the stream, and the occurrence of light pulses emanating from system bandwidth is to use a blue filter and adopt the transmitter. The OOK modulation format is proposed spectrally efficient modulation schemes such as DMT and for our system investigation accordingly. The modulated orthogonal frequency division multiplexing (OFDM) 30. bit stream using intensity modulation/ direct detection A data rate of 230 Mb/s was reported in 31, which uses (IM/DD) is therefore transmitted into the free space a bandwidth of 30 MHz with the nonreturn to zero (NRZ) medium and is received at PN/PIN photodetector receiver. on-off keying (OOK) data format and an avalanche The receiver is placed at a height, z = c = 0.85 meters on h Photo-detector. the x-y plane above the ground level. The receiver current, Y (i), is expressed as Y (i) = ζ X(i) h(i) + η, where ζ represents the responsivity of the photo detector in A/W, III. SYSTEM MODEL X(i) is the transmitted optical signal which is non- Each system model considers an indoor room having negative i.e. X(i) ≥ 0, h(i) denotes the channel impulse an area dimension 6.25 m 4 m for rectangular whereas response and η is the additive white Gaussian noise 2 the circular shape possesses a radius of 2.8205 in meters. (AWGN) with zero mean and variance σ . The channel Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 14 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light Communication System 2 impulse response h(i) between the i LED and the th y  1 Q(x) 2 dy (8) receiver is given as in 33 as exp  2 x (m1)A m () ( )g( ) cos( ), if 0  cos T  s Since the receiver is uniformly distributed on the x-y 2 c h(i) (1) 2  Di plane at z = c , let its probability distribution function  h 0, if   c (pdf) be defined by the function f(x , y ). The average o o outage area ratio, R, is now defined by 12 as the ratio of where, n, denotes the order of Lambertian emission and is the average outage area where the BER is greater than the expressed in terms of semi-angle (ϕ ) at half- 1/2 threshold level, P , to the total receiver plane area, S th total illuminance of a LED as, m = ln 2/ln cos(ϕ ), A is the 1/2 such that, area of the photodetector receiver, Di is the distance between a LED and a receiver, is the angle of incidence, ES( (x, y) ) P P BER th ϕ denotes the angle of irradiance and T(𝜓 ) presents the S Total gain of the optical filter. The gain of an optical a b R (9) S( (x, y) ) f ( , ) y dy  PBER Pth xo dxo concentrator is denoted by g(𝜓 ) whereas the receiver’s o o 0 0 field of view is expressed as 𝜓 . The optical c S Total concentrator’s gain, g(𝜓 ), is given as, -6 The threshold value, P , has been considered as 10 as th 2   per available literature 5.  , if 0  c 2 g( ) (2)  ( ) The RMS delay is a good measure to understand the  sin c  0, if ISI caused due to the spread of the LEDs. The mean    c delay and RMS delay of the impulse response is measured as, where µ denotes the refractive index. By using the Cartesian coordinate system, cos(ϕ) can be expressed as N 2 (t)  t h i1 i i  c (10) c N h 2 cos() (3) (t)  h 1 i1 i 2 2 2 2 (y y ) (c ) ( ) c x x h 0 i 0 i and, Further, It can be expressed that cos(𝜓 )= cos(ϕ). Since 2 N 2 () (t) Ts(𝜓 ) ≈Ts and g(𝜓 ) ≈g, the expression (1) can be written  t hi i1 i  (11)  RMS N 2 as (t)  h i1 i m1 gA (c ) T c s h where µ and denote the mean delay and RMS delay  (4) h i m3 respectively. The denotes the transmission delay due to 2 2 2 2 2 2  (c )( )(y y ) c x x h 0 i 0 i LED and denotes the impulse response due to LED. The received power at the detector due to all the LEDs can thus be expressed as IV. PROBLEM FORMULATION N i (5)  The proposed VLC system is expected to perform with P P h r t i i1 zero average outage area ratio, ’R’, within indoor room scenario under receiver mobility. So a requisite amount of i where P is the transmitted power of the i LED. t th SNR level is to be maintained throughout the indoor Accordingly, the electrical SNR, γ, can be given as room environment. The average outage area ratio, R, thus depends upon the number of LEDs which are distributed 2 within indoor room involving the different type of ( ) P r  (6) structures along with their positions. So the main 2  objective is to obtain the zero outage area ratio through optimization of the LED positions as well as involving For the OOK modulation scheme, the bit error rate can semi- angle. be expressed as in 34 as  Q( ) (7) P BER where, Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light 15 Communication System the receiver plane has been divided into L number of Table 2. Comparison of average outage area ratio ’R’ and the number of regular grids with respect to x and y-axis. Therefore the LEDs at various semi-angle values objective function for obtaining, R, is depicted as, Semi No. of LEDs No. of LEDs Angle Value of 'R' L l l (Rectangular) (Circular) R p U( ( , y ) ) (13) (Degrees).  x PBER i Pth i i1 2.5 530 140 0.00 l 5 170 40 0.00 where P is defined as the probability that a receiver is placed in the l grid and its corresponding BER is th 7.5 110 40 0.00 l expressed as P (x, y). Since the receiver distribution is BER 10 80 40 0.00 considered as uniform distribution, therefore the probability that a receiver lies in l grid would be given th 15 68 50 0.00 l as P = 1/ L, Also, the function U(Ω) is defined as, 20 70 50 0.00 1, 0 30 75 70 0.00 U() (14)  0, 0  40 90 85 0.00 Thus, a problem formulation is done to implement the 50 100 100 0.00 LED placement within the defined search space for the 60 120 110 0.00 optimal location of LEDs as per the figure 1. Further, the variation of LED semi-angle is analyzed for the 70 130 125 0.00 requirement of number of LEDs for receiver mobility. Thus, a total of N LEDs are distributed optimally using 80 140 135 0.00 HypEA search technique. Let the LED location is described as (x,y) and correspondingly the vector x = (x1, x2, x3, ......xN) and V. RESULTS AND DISCUSSION vector, y = (y1, y2, y3, .......yN) represents x and the y positions for N LEDs. Hence the problem statement for We have discussed two types of indoor VLC system the LED deployment would be as, models earlier. As per the problem stated, it is desired to achieved full mobility by using the minimum number of R (12) LED resources. Thus, the proposed models consist of min(x,y) rectangular and circular structures. The rectangular shape comprises of room dimension as (a b c) in meters This is subject to, 0 xi a, i ∈(1, 2, 3, ......N) and 0 with length, ′a′ as 6.5 m, breadth ′b′ as 4 m and height ′c′ yi b, i = (1, 2, 3, ......N) where a and b are the length as 3 m. The circular shape assumes the radius of 2.8205 and the breadth of the room. In order to compute the m and the height being 3 m. Both the structures have the average outage area ratio, R, as per the definition in (9). same floor area of 25 square meters. It is assumed that the detector receiver is spatially mobile on the i communication floor. The transmitted optical power, P , t of each LED is considered as 20 mW. The responsivity of the receiver detector is taken as 0.53 A/W with its physical area as 1 square cm. The gain of an optical filter ′T ′ and the Gain of an optical concentrator ′g′ is s considered as 1 and 2 respectively. The communication floor is assumed to be at a height (c ) of 0.85 m. The total h floor area has been divided into 10,000 number of grids denoted as ’L’. The receiver has equal probability to move anywhere within the indoor room at communication floor. The threshold value of average bit -6 error rate, P , is described as 10 as per available th literature 10. This refers to as the threshold level of average BER below which the transmission is error-free and above which the receiver detects an error. The results are thus analyzed and presented for the proposed system models in this section with the main contribution as, i) Average Outage area ratio versus Number of LEDs ii) Number of LEDs versus the LED Fig.2. Average Outage Area Ratio vs. No. of LEDs semi- angle iii) RMS delay versus LED semi- angle. Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 16 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light Communication System seen from the plot that any further increase in semi-angle A. Average outage area ratio o also increases the requirement of LEDs resources. At 40 The analysis of average outage area ratio "R" semi-angle, the LED requirement for rectangular and circular model remain at 90 and 85 respectively. However, represents the ratio of the area where the receiver detects a transmission error resulting in the system outage to the this increases to a level of 140 and 135 LEDs at semi- o angle value of 80 . In summary, this analysis shows that ratio of the entire receiver floor area. For evaluation of mobility aspects of the receiver, the receiver is moved to the optimal design of semi-angle can reduce the resource requirement of LED deployment for the proposed indoor each one of the 10000 grid locations. The main objectives of the analysis of the proposed system models are to mobile VLC system. The overall analysis results are tabulated in table II. achieve full receiver mobility within the indoor room as proposed. The plot between the average outage area ratio C. RMS delay versus LED semi- angle and the number of LEDs deployed within the indoor The analysis of RMS delay is presented in figure 4. room is presented in figure 2 for both the models at a o particular semi-angle of (ϕ = 60 ). This can be observed 1/2 Table 3. Comparison of Optimal System Performance from the plot that in the rectangular model, the value of ’R’ decreases gradually while the number of LEDs is Parameter Rectangular circular increased. This can also be observed that as we increase o o Semi angle 15 10 the number of LEDs in the rectangular model, the system outage decreases although the outage remains at 1 Number of LEDs 68 40 (complete outage) up till 30 LEDs. The value of "R" Value of 'R' 0.00 0.00 remain at 0.7684 at 40 LEDs. Further, the value of "R" continuously declines and finally reduces to zero with Minimum RMS -11 -12 110 LEDs. Thus the full mobility is achieved with zero 7.148933 x 10 6.946209 x 10 delay (seconds) value of "R" at 110 LEDs. In the case of circular structure, initially, the value of "R" remain 1 till 60 LEDs but after Maximum RMS -10 -11 2.422964x10 7.891754 x 10 delay (seconds) that, there is a sharp decline in the number of LEDs is increased. It can be observed that the value of "R" becomes 0.5246 with the deployment of 70 LEDs. Finally, the zero value of "R" is achieved with 110 LEDs. Hence the fully mobile system within the indoor room for the circular structure is attained with 110 LEDs. This clearly shows that circular structures can have full mobility at less resource deployment. Therefore, clearly resulting in 9 percent less resource allocation in this case for full mobility of an indoor VLC system. The value of "R" at various numbers of LEDs are tabulated in table I. B. Number of LEDs versus semi- angle In this section, we analyze the impact of semi-angle on average outage area ratio "R" and the number of LEDs deployed to achieve full mobility. This can be clearly observed that semi-angle plays a significant role and impacts the value of "R". The variation of LED semi- angle and the corresponding number of LEDs is plotted in figure 3 for attaining the zero value of "R". This can be observed from the plot that at semi-angle value of the number of LEDs corresponds to 530 LEDs in case of rectangular model as compared to 140 LEDs in circular model. At such a narrow-angle, the LED shows the high degree of directionally, therefore, Fig.3. Semi angle vs. No. of LEDs for 'R' = 0 increasing the overall data density. However, as the semi- The RMS delay indicates the level of inter-symbol angle is increased, the requirement of LEDs also become interference (ISI) which largely affects the VLC system’s lesser till an optimal value of semi-angle to attain full bandwidth. The mean delay and RMS delay are crucial to receiver mobility. Accordingly, This can also be observed determine the data rate of the system. The data rate can that for the rectangular model, the minimum number of o easily be depleted by higher interference levels. The LEDs for system mobility is achieved at ϕ = 15 . In this 1/2 increase in RMS delay is the result of multipath model, 68 LEDs are required to ensure zero value of ’R’ propagation. Due to Multipath propagation, the pulse gets at this semi-angle. However, for the circular model, the o spread therefore limiting the system's bandwidth. This system is optimized at ϕ = 10 with 40 LEDs for 1/2 necessitates the need to mitigate the effect of multipath making the VLC system fully mobile. This may also be Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light 17 Communication System that should reduce the RMS delay. So RMS delay has to rectangular and circular structures have been investigated be minimized as much as possible. In general, the width extensively. The system mobility parameters especially of the transmitted pulse should be at least ten times as the average outage area ratio have been discussed with high as the value of RMS delay. This is observed in both respect to the number of LEDs. The effect of variation of the system models that RMS delay increases with semi-angle on the LED resources has been largely increase in LED semi-angle. The narrow semi-angle analyzed. Further, the RMS delay parameter has been makes the beam more directional thus such beams can investigated and its impact on data rate has been studied. deliver higher data density. However, this can be A comparison between the two system models has been observed from the respective plot that at extremely lower accomplished accordingly to identify the use of optimal o semi-angles, at optimal value of semi-angle of 15 , the resources for the indoor mobile VLC communication RMS delay of 0.0714 nanoseconds(ns) is achieved system. Hence, It may be concluded that LED resources whereas, for the circular model, the RMS delay is can be optimized without degrading the system o computed as 0.00694 ns at 10 semi-angle value. This is parameters using HypEA including the computation of the optimal scenario where the least number of LEDs not the optimal semi-angle value for different structures. In only attains to full mobility but also results in the optimal future, the multi-objective problems related to VLC value of RMS delay. Correspondingly, the maximum systems could be implemented using HypEA for RMS delay is obtained as 0.2429 ns and 0.0789 ns performance analysis. respectively for rectangular and circular models. It can also be seen that the RMS value deteriorates as the semi- APPENDIX - A angle is increased which indicates that higher value of Hyper-heuristic Evolutionary Algorithm. semi-angle increases the level of ISI thus increasing the o pulse spread. The RMS delay at 80 is observed as 1.65 The Hyper-heuristics are defined as heuristics to ns and 1.85 ns respectively for circular and rectangular choose heuristics 35. It reduces the search effort to find models which is extremely high as compared to the a solution and hence considered as an efficient technique. values obtained at lower semi-angle values. This With the objective of finding optimal solutions, meta- indicates that higher data rates can be achieved at lower heuristic operates directly on the problem search space semi-angle values. This can also be observed that RMS whereas the hyper-heuristic works on the heuristics delay for the circular structure is marginally lower as search space which contains all the heuristics that is used compared to the rectangular structure. The maximum and to solve a given problem. The term hyper-heuristics was minimum value of RMS delay along with the optimal coined by Cowling 36. The hyper-heuristics is able to value of LEDs have been tabulated in table III. manage the choice of which lower-level heuristic method is to be applied at any given point of time depending upon the ability of the heuristic in exploring the search space. The basic objective of hyper-heuristics is to evolve more general systems that are able to cater for a wide range of problem domains. The basic framework of the HypEA is presented in figure 5. There are two phases in which the first phase selects the type of mutation to be adopted. The CR is a random number drawn from the uniform distribution on a unit interval to select an Evolutionary Algorithm (EA) model either with copy or with exchange mutation with equal probability. The values of h and h denotes the b e beginning and ending of the subscripts of low-level hyper-heuristics thus selected. A specific low-level heuristic is selected in the second phase within the Fig.4. RMS delay (s) vs. LED semi angle for 'R' = 0 VI. CONCLUSION We have analyzed the LED-based indoor mobile VLC system based on two different structures using HypEA Fig.5. Framework of Hyper-heuristics technique. The deployment of LEDs using HypEA for Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 18 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light Communication System selected group. The reinforcement learning strategy is level heuristics during each iteration of the search by used in this phase with adaptive weights using roulette- increasing its weight and punish poorly performing ones wheel for selecting a specific model of EA. The pseudo by decreasing its weight. code of the HypEA is given in algorithm below. REFERENCES 1 A. Kelly, ―High-speed GaN micro-LED arrays for data communications,‖ Proceedings of the 14th ICTON Coventry, U.K., pp.1-5, 2012. 2 S. 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Ji, ―Evolutionary algorithm-based process described above with regards to the crossover and optimization of the signal to noise ratio for indoor visible- mutation operators, twelve low-level heuristics are light communication utilizing white light-emitting diode,'' designed for the hyper-heuristic. These are expressed in IET Optoelectronics, vol. 6, no. 6, pp. 307-317, Sep. 2012. Table IV. 12 Rui Guan, Jin Yuan-Wang, Yun Peng-Wen, Jun Bo-Wang, ―PSO-based LED deployment optimization for visible Table 4. Set of Low Level Heuristics Designed for HypEA light communications‖, IEEE International Conference on Wireless Communications and Signal Processing (WCSP), China, pp. 24-26 Oct. 2013. 13 C. Chow, C. Yeh, Y. Liu, P. Huang, and Y. Liu, ―Adaptive scheme for maintaining the performance of the in-home white-led visible light wireless communications using OFDM, ‖ Optics Communications, vol. 292, no. 1, pp. 49- 52, 2013. 14 Y. Wang, N. Chi, J. Yu, and H. Shang, ―Demonstration of The hyper-heuristic selects a promising low-level 575-mb/s downlink and 225-mb/s uplink bi-directional heuristic at the beginning of every iteration based on the scm-WDM visible light communication using RGB led information about the effectiveness of each low-level and phosphor-based led'' Optics Express, vol. 21, no. 1, pp. 1203-1208, 2013. heuristic accumulated in previous runs. This is 15 M. Biagi, T. Borogovac, and T. Little, ―Adaptive receiver implemented through the principle of reinforcement for indoor visible light communications,‖ Journal of learning 20. The key idea is to reward improving low- Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19 Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light 19 Communication System Lightwave Technology, vol. 31, no. 23, pp. 3676-3686, 2010. 2013. 32 Mehdi Rouissat, A. Riad Borsai, M. Chikh-Bled, 16 A. Nabih, Z. 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Arnon, ―Multiple access resource Authors’ Profiles allocation in visible light communication systems,‖ Journal of Lightwave Technology, vol. 32, no. 8, pp. Ram Sharma received B.Tech. and 1594-1600, 2014. M.Tech. degrees in electronics and 22 S. Arnon, "Visible Light Communication," Cambridge communication engineering from M.M.M. University Press, Feb. 2015. university of Technology, Gorakhpur, India, 23 R. F. Karlicek, "Smart lighting-Beyond simple and Department of electronics and illumination," in Photonics Society Summer Topical communication engineering, School of Meeting Series, IEEE, pp. 147-148, 2012. Engineering, ITM University, Gurgaon, 24 W. W. R. Forum, Available:, 2014 India respectively. He is currently working 25 O. H. G. Access. Available: as a teaching cum research fellow at The NorthCap University, 26 IEEE 802.15 WPAN™ Task Group 7 (TG7), Visible Gurgaon, India. His current research interests are optical Light Communication, Available: wireless communication including visible light and infrared (IR) pub/TG7.html, 3 March 2015. communication systems. 27 T. Kishi, H. Tanaka, Y. Umeda, and O. Takyu, "A High- speed LED driver that sweeps out the remaining carriers for visible light communications," Journal of Lightwave A. Charan Kumari received her Ph.D. Technology, vol. 32, pp. 239-249, 2014. from Dayalbagh Educational Institute, 28 G. M. Lazzerini, F. Di Stasio, C. Flechon, D. J. Caruana, under collaboration with Indian Institute of and F. Cacialli, ―Low-temperature treatment of Technology, Delhi, India, under their semiconducting interlayers for high-efficiency light MOU. Currently she is associated with emitting diodes based on a green-emitting polyfluorene THE NORTHCAP UNIVERSITY, India, derivative,‖ Applied Physics Letters, vol. 99, no. 24, 2011. as an associate professor in the department 29 Z. Ghassemlooy, W. Popoola, and S. Rajbhandari, Optical of Computer Science and Engineering. She Wireless Communications: System and Channel Modeling has an excellent teaching experience of 15 years in various with MATLAB. Boca Raton, FL: Taylor & Francis Group, esteemed institutions and received various accolades including 2012. the best teacher award. Her current research interests include 30 G. Cossu, A. M. Khalid, P. Choudhury, R. Corsini, and E. Search-based Software engineering, Evolutionary computation, Ciaramella, ―3.4 Gbit/s visible optical wireless and soft computing techniques. She has published papers in transmission based on RGB LED,‖ Opt. Exp., vol. 20, pp. journals of national and international repute. She has delivered rd B501–B506, 10 Dec. 2012. an invited talk at 43 CREST open workshop on Hyper- 31 J. Vucic, C. Kottke, S. Nerreter, K. Habel, A. Buttner, K. heuristics at UCL, London. She is a member of IEEE, Computer D. Langer, and J. W. Walewski, ―230 Mbit/s via a Society of India (CSI) and Systems Society of India (SSI). wireless visible-light link based on OOK modulation of phosphorescent white LEDs,‖ in Proc. Opt. Fiber Communication./Nat. Fiber Opt. Eng. Conf., pp. 1–3, How to cite this paper: Ram Sharma, A. Charan Kumari,"Performance Analysis of Rectangular and circular Shape Building Deployment for an Indoor Visible Light Communication System", International Journal of Computer Network and Information Security(IJCNIS), Vol.9, No.7, pp.11-19, 2017.DOI: 10.5815/ijcnis.2017.07.02 Copyright © 2017 MECS I.J. Computer Network and Information Security, 2017, 7, 11-19