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1 Project: IEEE 8.bb Task Group Title: IEEE 8.bb Reference Channel Models for Indoor Environments Date Submitted: July 6, 8 Source: Murat Uysal (Ozyegin University), Farshad Miramirkhani (Ozyegin University), Tuncer Baykas (Istanbul Medipol University), Nikola Serafimovski (purelifi Ltd.), and Volker Jungnickel (Fraunhofer HHI). Address: Ozyegin University, Nisantepe Mh. Orman Sk. No:34-36 Çekmekoy Istanbul, Turkey Voice: +9 (6) , Fax: +9 (6) , murat.uysal@ozyegin.edu.tr Abstract: This contribution proposes LiFi reference channel models for indoor environments such as office, home and manufacturing cell. Purpose: To introduce reference channel models for the evaluation of different PHY proposals. Notice: This document has been prepared to assist the IEEE 8.. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by 8..

2 IEEE 8.bb Reference Channel Models for Indoor Environments

3 o Introduction Outline Overview of Channel Modeling Methodology o Indoor Scenarios under Consideration: Empty Room, Office, Home, Manufacturing Cell Modeling of the Indoor Environment Source Modeling Illumination Level Requirements Channel Impulse Responses (CIRs) Effective Channel Responses Channel Characteristics o Conclusions 3

4 Overview of Channel Modeling Methodology o A flexible and efficient method for realistic VLC channel modeling Wavelength dependency Realistic light sources Effect of objects within the environment and types of surface (coating) materials For additional details see IEEE a, Channel Modeling for Visible Light Communications IEEE a, TG7r channel model document for high-rate PD communications 4

5 Channel Impulse Response (CIR) o Based on Monte Carlo Ray Tracing. o Sobol sampling is used for speeding up ray tracing. o The Zemax non-sequential ray-tracing tool generates an output file, which includes all the data about rays such as the detected power and path lengths for each ray. o The data from Zemax output file is imported to MATLAB and using these information, the multipath CIR is expressed as i P i = the power of the i th ray τ i = the propagation time of the i th ray δ(t) = the Dirac delta function N r = the number of rays received at the detector N r h t P t i i 5

6 Effect of LED Response o In addition to the multipath propagation environment, the low-pass characteristics of the LED sources should be further taken into account in channel modelling. H LED f LED H f e f cut-off LED Model [] j f LED Model [] f cut-off f ln f cut-off : 3 db cut-off frequency of the LED [] L. Grobe, and K. D. Langer, Block-based PAM with frequency domain equalization in visible light communications, In IEEE Globecom Workshops (GC Wkshps), pp. 7-75, 3. [] M. Wolf, S. A. Cheema, M. Haardt, and L. Grobe, On the performance of block transmission schemes in optical channels with a Gaussian profile, In 6th International Conference on Transparent Optical Networks (ICTON), pp. -8, 4. 6 H LED (f) [db] f cut-off =5 MHz f cut-off = MHz f cut-off =5 MHz f cut-off = MHz LED Model LED Model

7 Simulation Scenario : Empty Room o We consider an empty room with a size of 6 m 6 m 3 m with plaster ceiling/walls and pinewood floor. 7

8 Simulation Parameters Room size Materials Objects specifications Luminary Specifications Number of luminaries 9 Number of PDs 7 Receiver area cm 6 m 6 m 3 m Walls: Plaster, Ceiling: Plaster, Floor: Pinewood Cell phone: Black gloss paint (5.5 cm.5 cm.5 cm) Human body: Shoes: Black gloss paint Head & Hands: Absorbing Clothes: Cotton Brand: CR6-8L Cree Inc. Half viewing angle: 4º 8

9 Light Source o In simulation study, we use the LED luminary CR6-8L from Cree. Simulated emission pattern in Zemax 9

10 Illumination Levels o Based on the properties of luminary, required illumination level (5 lx) and the size of room, we arrange the luminaries as follows: Delivered light output from 737 lumens each luminary Average of illumination level 53 lx Uniformity of illumination.64 Arrangement of luminaries Evaluation of illumination level in Zemax

11 33 July 8 Illumination Patterns Illumination Level (Lux) Cells in Y Direction Cells in X Direction Cells in Y Direction Cells in X Direction Simulated illumination levels in Zemax Illumination level contours in Matlab o The minimum and maximum values of illumination are lx and 76.4 lx.

12 Location of Test Points (Receivers) o We consider cells with equidistant spacing of.6 m in x and y directions. o We consider a user with a height of.8 m who holds the phone in his hand next to his ear with 45 rotation upward the ceiling and at a height of.65 m. The cell phone is equipped with a single photodetector. We consider seven possible locations for the photodetectors. Room under consideration with green circles denoting luminaires Location and rotation of test points

13 Sample CIR Results for D5 (/) 3 x -4 P 3, 3 x -4 P 7, 6 x -6 P,3 5 4 Power Power Power Time(ns) 4 6 Time(ns) 4 6 Time(ns) 6 x -5 P 4,4 3 x -4 P 6,5 5 4 Power 3 Power 4 6 Time(ns) 4 6 Time(ns) 3

14 Sample CIR Results for D5 (/) 3 x -5 P,6 5 x -5 P 8,7 x -4 P,8 4 Power Power 3 Power 4 6 Time(ns) 4 6 Time(ns) 4 6 Time(ns) x -4 P 5,9 x -5 P 9, Power Power 4 6 Time(ns) 4 6 Time(ns) 4

15 Sample Optical Channel Responses for D5-6 P 3, P 7, -7 P,3 P 4,4 P 6,5-8 P,6 H(f) [db] -9 P 8,7 P,8 P 5,9 P 9,

16 -6-7 July 8 Sample Effective Channel Responses for D5 LED Model, f cut-off =5 MHz LED Model, f cut-off = MHz LED Model, f cut-off =5 MHz LED Model, f cut-off = MHz P 3, P 7, -7 P 3, P 7, -7 P 3, P 7, -7 P 3, P 7, H eff (f) [db] P,3 P 4,4 P 6,5 P,6 P 8,7 H eff (f) [db] P,3 P 4,4 P 6,5 P,6 P 8,7 H eff (f) [db] P,3 P 4,4 P 6,5 P,6 P 8,7 H eff (f) [db] P,3 P 4,4 P 6,5 P,6 P 8,7 - P,8 P 5,9 - P,8 P 5,9 - P,8 P 5,9 - P,8 P 5,9-5 5 P 9, P 9, P 9, P 9, H eff (f) [db] LED Model, f cut-off =5 MHz o In the effective channel responses of P,3, P,6 and P 9,, frequency selectivity are more pronounced. It is a result of the fact that these locations are close to the walls (see p. ) and therefore more reflected rays are received (see corresponding CIRs in p. 3 and p. 4). o In the rest of this presentation, the LED Model with cut-off frequency of MHz is considered. P 3, P 7, P,3 P 4,4 P 6,5 P,6 P 8,7 P,8 P 5,9 P 9, H eff (f) [db] LED Model, f cut-off = MHz P 3, P 7, P,3 P 4,4 P 6,5 P,6 P 8,7 H eff (f) [db] P,8 P - 5,9 P 9, LED Model, f cut-off =5 MHz P 3, P 7, P,3 P 4,4 P 6,5 P,6 P 8,7 H eff (f) [db] P,8 - P 5,9 P 9, LED Model, f cut-off = MHz P 3, P 7, P,3 P 4,4 P 6,5 P,6 P 8,7 P,8 P 5,9 P 9,

17 H July x Cells in Y Direction H.5.5 x Cells in Y Direction H.5.5 x Cells in Y Direction D Spatial Distribution of DC Gains & Channel Characteristics (/) Cells in X Direction D Cells in X Direction D Cells in X Direction x x x H.5.5 x Cells in Y Direction H Cells in Y Direction H x -5 x Cells in Y Direction D Cells in X Direction D Cells in X Direction D Cells in X Direction 7 x x x H.5.5 x Cells in Y Direction Cells in X Direction Average over Cells RMS (ns) H D D D D D D D D7 x

18 Spatial Distribution of DC Gains & Channel Characteristics (/) x D D D3 D4 D5 D6 D7 H Cells in X/Y Direction 8

19 Cumulative Distribution Function (CDF) of Path Loss Cumulative Density Function (CDF) D6 D Path Loss [db] o It can be noted that D, D, D3, D4, D5 and D6 have similar path loss values in the range of 5.95 db-5.94 db. In comparison to them, D7 has about. db-3. db more path loss on average since there is no LOS component. D D D3 D4 D5 9

20 Simulation Scenario : Office o Typical office places include furniture (e.g., desk, chairs, cubicles etc), various equipments (e.g., computers, printers etc) and personnel. Open Office Office With Cubicles

21 Room size Materials Objects Objects specifications Luminary Specifications Simulation Parameters Number of luminaries 3 Receiver area cm 4 m 4 m 3 m Walls: Plaster, Ceiling: Plaster, Floor: Pinewood 6 desks and a chair paired with each desk 6 laptops on each desk 6 cubicles (optional) 9 human bodies Cubicles: Plaster Desk: Pinewood (Typical height of.85 m) Chair: Pinewood Laptop: Black gloss paint Human body: Shoes: Black gloss paint Head & Hands: Absorbing Clothes: Cotton Brand: LR4-38SKA35 Cree Inc. Half viewing angle: 4º

22 Light Source (Transmitter) o In simulation study, we use the LED luminary LR4-38SKA35 from Cree. Simulated emission pattern in Zemax

Illumination Levels o Based on the properties of employed luminary, required illumination level (5 lx) and the size of office place, we arrange the luminaries as follows:

23 Illumination Levels o Based on the properties of employed luminary, required illumination level (5 lx) and the size of office place, we arrange the luminaries as follows: Delivered light output from 354 lumens each luminary Average of illumination level 533 lx Uniformity of illumination.5 Arrangement of luminaries Evaluation of illumination levels in Zemax 3

24 July 8 Illumination Patterns Illumination Level (Lx) Simulated illumination levels in Zemax Illumination level contours in Matlab o Different colors show different values of illumination (lx) at the height of desk in office place. Red indicates the highest illumination level. o The minimum and maximum values of illumination are 78 lx and 7 lx respectively. Cells in Y Direction Cells in X Direction Cells in Y Direction Cells in X Direction

Location of Test Points (Receivers) o 4 test points are chosen which are categorized into three groups: In the corridors at a height of.7 m with 45º rotation (e.g., people who stand with a cell phone in hand) On the top of chairs at a height of.

25 Location of Test Points (Receivers) o 4 test points are chosen which are categorized into three groups: In the corridors at a height of.7 m with 45º rotation (e.g., people who stand with a cell phone in hand) On the top of chairs at a height of.95 m with 45º rotation (i.e., people with a cell phone in hand) On the top of chairs at a height of. m with 45º rotation (e.g., people who sit with a cell phone in hand to his/her ear) D-D D3-D8 D9-D4 D9 D3 D Location and rotation of test points 5

26 Test Points (Open Office) 6

27 Test Points (Office with Cubicles) 7

28 Optical Channel Responses (Open Office) H(f) [db] D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 8

29 Effective Channel Responses (Open Office) H eff (f) [db] D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 9

30 Channel Characteristics RMS (ns) D D D D D D D D D D D D D D D D D D D D D D D D H

31 Optical Channel Responses (Office with Cubicles) H(f) [db] D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 3

32 Effective Channel Responses (Office with Cubicles) H eff (f) [db] D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 D5 D6 D7 D8 D9 D D D D3 D4 3

33 Channel Characteristics RMS (ns) D D D D D D D D D D D D D D D D D D D D D D D D H

34 Simulation Scenario : Office with Secondary Light o In this office environment, there are two light sources; one of them is the main light source at the ceiling and the other one is mounted on the desk to provide task lighting. 34

35 Simulation Parameters Room size 5 m 5 m 3 m Materials Walls: Plaster, Ceiling: Plaster, Floor: Pinewood Objects desk and a chair paired with desk laptop on the desk, desk light on the desk, library couch, coffee table, window, human bodies Objects specifications Desk: Pinewood (Typical height of.88 m) Chair: Black gloss paint, Laptop: Black gloss paint Desk light: Black gloss paint, Library: Pinewood, Window: Glass Couch: Cotton, Coffee table: Pinewood Human body: Shoes: Black gloss paint Head & Hands: Absorbing Clothes: Cotton Luminary Specifications Brand: LR4-38SKA35 Cree Inc. Half viewing angle: 4º Number of luminaries on the ceiling for the desk light Receiver area cm 35

36 Light Source (Transmitter) o In simulation study, we use the LED luminary LR4-38SKA35 from Cree. Simulated emission pattern in Zemax 36

37 Illumination Levels o Based on the properties of employed luminary, required illumination level (5 lx) and the size of office place, we arrange the luminaries as follows: Delivered light output from 3796 lumens each luminary Average of illumination level 7 lx Uniformity of illumination.449 Arrangement of luminaries Evaluation of illumination levels in Zemax 37

38 44 July 8 Illumination Patterns Illumination Level (Lx) Cells in Y Direction Cells in X Direction Simulated illumination levels in Zemax Illumination level contours in Matlab Cells in Y Direction Cells in X Direction o The minimum and maximum values of illumination are 9 lx and 9 lx respectively. 38

39 Location of Test Points (Receivers) o test points are chosen: On the desk next to the laptop at a height of.88 m (e.g., a USBtype device connected to laptop) On the top of desk light at a height of.5 m with 45º rotation toward the source on the ceiling D D D D 39

40 Optical and Effective Channel Responses & Channel Characteristics S R R D S D S R R D S D -9-9 H(f) [db] H eff (f) [db] RMS (ns) H S R R D S D

41 Simulation Scenario 3: Home o We consider a living room with table, chairs, couch, coffee table and human bodies. 4

42 Simulation Parameters Room size Materials Objects Object Specifications Luminary Specifications Number of luminaries 9 Receiver area cm 6 m 6 m 3 m Walls: Plaster, Ceiling: Plaster, Floor: Pinewood Table with 4 chairs Couch Coffee table 4 human bodies Tables: Wooden with size of m m.9 m Chairs: Wooden matched with table Couch: Cotton Coffee table: Glass Human body: Shoes: Black gloss paint Head & Hands: Absorbing Clothes: Cotton Brand: CR6-8L Cree Inc. Half viewing angle: 4º 4

43 Light Source o In simulation study, we use the LED luminary CR6-8L from Cree. Simulated emission pattern in Zemax 43

44 Illumination Levels o Based on the properties of luminary, required illumination level (5 lx) and the size of room, we arrange the luminaries as follows: Delivered light output from 84 lumens each luminary Average of illumination level 53 lx Uniformity of illumination.968 Arrangement of luminaries Evaluation of illumination level in Zemax 44

45 Illumination Patterns Illumination Level (Lx) Cells in Y Direction Cells in X Direction Simulated illumination levels in Zemax Illumination level contours in Matlab Cells in Y Direction Cells in X Direction o The minimum and maximum values of illumination are 39 lx and 69 lx. 45

46 Location of Test Points (Receivers) o 8 test points are chosen which are categorized into four groups: On the coffee table at a height of.6 m with 45º rotation Next to the wall at a height of.7 m (e.g., standing people) with 45º rotation On the table at a height of.9 m On the top of couch at height of. m (e.g., sitting people) with 45º rotation D D-D3 D4-D7 D8 46

47 Optical Channel Responses D D D3 D4 D5 D6 D7 D8 H(f) [db]

48 Effective Channel Responses D D D3 D4 D5 D6 D7 D8 H eff (f) [db]

49 Channel Characteristics RMS (ns) H D D D D D D D D

50 Simulation Scenario 4: Manufacturing Cell o We consider a manufacturing cell with two robots. 5

51 Simulation Parameters Room size Materials Objects Object Specifications LED Specifications Number of LEDs 6 Receiver area cm 8.3 m 9.45 m 6.8 m (See p.48 for exact layout) Red Walls: Concrete Green Walls: Aluminum metal Blue Walls: Plexiglas (PMMA) Ceiling: Aluminum metal Floor: Concrete Two robots Robot: Galvanized steel metal Height of Robot:.7 m Height of Plexiglas boundary:.5 m Brand: MC-E Cree Xlamp Inc. Half viewing angle: 6º 5

52 Light Source (Transmitter) o In simulation study, we use the LED Xlamp MC-E from Cree. Simulated emission pattern in Zemax Emission pattern of six LEDs which cover 36º 5

53 Location of Luminaries (Transmitters) o 6 transmitters are located at the head of the robot, arranged on the six sides of a cube to cover 36º. LED5 LED LED LED3 LED4 LED6 53

54 Location of Test Points (Receivers) o Test points are considered on the top of the Plexiglas boundary which are looking in the direction of the robots. 54

55 Optical Channel Responses H(f) [db] LED D D D3 D4 D5 D6 D7 D8 H(f) [db] LED D D D3 D4 D5 D6 D7 D8 H(f) [db] LED3 D D D3 D4 D5 D6 D7 D8 H(f) [db] LED4 D D D3 D4 D5 D6 D7 D H(f) [db] LED5 D D D3 D4 D5 D6 D7 D8 H(f) [db] LED6 D D D3 D4 D5 D6 D7 D8 H(f) [db] All LEDs D D D3 D4 D5 D6 D7 D

56 Effective Channel Responses H eff (f) [db] LED D D D3 D4 D5 D6 D7 D8 H eff (f) [db] LED D D D3 D4 D5 D6 D7 D8 H eff (f) [db] LED3 D D D3 D4 D5 D6 D7 D8 H eff (f) [db] LED4 D D D3 D4 D5 D6 D7 D H eff (f) [db] LED5 D D D3 D4 D5 D6 D7 D8 H eff (f) [db] LED6 D D D3 D4 D5 D6 D7 D8 H eff (f) [db] All LEDs D D D3 D4 D5 D6 D7 D

57 TX-RX (ns) D D D LED D D D D LED LED3 RMS H D D D D D D D D D D D D D D D D D Channel Characteristics TX-RX RMS (ns) H TX-RX (ns) H D D D D D D LED4 D All D D LEDs D D D D D D D D D D LED5 D D D D D D D D LED6 D D D D D RMS

58 Conclusions o This contribution proposes LiFi reference channel models for indoor environments to assist the IEEE 8.bb. o Our results are extended versions of the previous contribution in 8.5.7r where the effect of LED response is further considered. 58

59 Acknowledgement o The work of M. Uysal and T. Baykas was supported by the Turkish Scientific and Research Council (TUBITAK) under Grant 5E3. 59

09/2018 doc.: IEEE /1582r2. IEEE P Wireless LANs. IEEE bb Reference Channel Models for Indoor Environments

09/2018 doc.: IEEE /1582r2. IEEE P Wireless LANs. IEEE bb Reference Channel Models for Indoor Environments 9/8 doc.: IEEE 8.-8/58r IEEE P8. Wireless LANs IEEE 8.bb Reference Channel Models for Indoor Environments Date: 8-9- Author(s) Name Affiliation Address Phone Email Ozyegin University, Murat Uysal Cekmekoy