Visible Light Communication (VLC)

Transcription

1 Visible Light Communication (VLC) Resource Allocation in Multi-User Environment Dima Bykhovsky & Shlomi Arnon Optical Wireless Communication Laboratory Ben-Gurion University of the Negev International Congress of Imaging Science (ICIS) May 2014 Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

2 Challenges of VLC Challenges addressed in the presented research Currently, there is no effective scalable solution for big-area apartments, conference halls, corridors and etc. Some of the VLC challenges are: Efficient scalability with growth in number of transmitters and/or users Fairness and/or QoS between users in scalable environment Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

3 Challenges of VLC Challenges addressed in the presented research Currently, there is no effective scalable solution for big-area apartments, conference halls, corridors and etc. Some of the VLC challenges are: Efficient scalability with growth in number of transmitters and/or users Fairness and/or QoS between users in scalable environment Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

4 Challenges of VLC Challenges addressed in the presented research Currently, there is no effective scalable solution for big-area apartments, conference halls, corridors and etc. Some of the VLC challenges are: Efficient scalability with growth in number of transmitters and/or users Fairness and/or QoS between users in scalable environment Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

5 Resource Allocation in VLC Resource Allocation Why is it so important? The promising solution for these challenges is the resource allocation Resource allocation may be used for Improved scalability Improvement of communication performance Quality of service (QoS) and/or fairness between users Spatial reuse is possible Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

6 Resource Allocation in VLC Resource Allocation Why is it so important? The promising solution for these challenges is the resource allocation Resource allocation may be used for Improved scalability Improvement of communication performance Quality of service (QoS) and/or fairness between users Spatial reuse is possible Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

7 Resource Allocation in VLC Resource Allocation Why is it so important? The promising solution for these challenges is the resource allocation Resource allocation may be used for Improved scalability Improvement of communication performance Quality of service (QoS) and/or fairness between users Spatial reuse is possible Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

8 Resource Allocation Requirments Resource Allocation General Constraints Centralized control Minimum communication between transmitters Real-time re-allocation Reasonable allocation algorithm complexity Modular solution Same hardware is used for resource-allocated and for conventional communication T x T x Downlink Communication Controller Communication Data Time-Sync Resource Allocation Channel State Uplink R x R x Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

9 Resource Allocation Requirments Resource Allocation General Constraints Centralized control Minimum communication between transmitters Real-time re-allocation Reasonable allocation algorithm complexity Modular solution Same hardware is used for resource-allocated and for conventional communication T x T x Downlink Communication Controller Communication Data Time-Sync Resource Allocation Channel State Uplink R x R x Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

10 Resource Allocation Requirments Resource Allocation General Constraints Centralized control Minimum communication between transmitters Real-time re-allocation Reasonable allocation algorithm complexity Modular solution Same hardware is used for resource-allocated and for conventional communication T x T x Downlink Communication Controller Communication Data Time-Sync Resource Allocation Channel State Uplink R x R x Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

11 Resource Allocation Requirments Resource Allocation General Constraints Centralized control Minimum communication between transmitters Real-time re-allocation Reasonable allocation algorithm complexity Modular solution Same hardware is used for resource-allocated and for conventional communication T x T x Downlink Communication Controller Communication Data Time-Sync Resource Allocation Channel State Uplink R x R x Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

12 Resource Allocation Requirments Resource Allocation Why is it so complicate? Transmitters Receiver VLC constraints Same wavelength Line-of-sight (LOS) path Diffuse reflections Arbitrary transceiver location Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

13 Resource Allocation Requirments Resource Allocation Why is it so complicate? Transmitters Receiver VLC constraints Same wavelength Line-of-sight (LOS) path Diffuse reflections Arbitrary transceiver location Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

14 Resource Allocation Requirments Resource Allocation Why is it so complicate? Transmitters Receiver VLC constraints Same wavelength Line-of-sight (LOS) path Diffuse reflections Arbitrary transceiver location Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

15 Resource Allocation Requirments Resource Allocation Why is it so complicate? Transmitters Receiver VLC constraints Same wavelength Line-of-sight (LOS) path Diffuse reflections Arbitrary transceiver location Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

16 Optical OFDM DC-biased Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) DCO-OFDM Intensity modulation/direct-detection State-of-the-art bit-rate performance Inherent multi-user (MU) capability Highly flexible resource allocation M-QAM Symbols Received Symbols Map S/P Map P/S X0 X1 XN/2-1 Y0 Y1 YN/2-1 IFFT FFT x0 x1 xn-1 y0 y1 yn-1 Add CP S/P Remove CP Remove Bias xn-g x0 x1 xn-1 Add DC Bias Map Clipping P/S Linear Mapping D/A Channel sn Noise D/A Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

17 Resource Allocation OFDM Resource allocation is based on channel frequency response Gain Frequency Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

18 Resource Allocation OFDM Assignment of bit-and-power for each subchannel Gain Bit-and-power allocation Frequency Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

19 Resource Allocation MU OFDM Transmitter Reuse by OFDM Resource Allocation Gain Frequency User I User II Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

20 Resource Allocation MU OFDM Transmitter Reuse by OFDM Resource Allocation Gain Frequency Reuse is possible User I User II User III Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

21 Resource Allocation MU OFDM Transmitter Reuse by OFDM Resource Allocation Gain User I Frequency User II Reuse is possible User III Cross-interference Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

22 Resource Allocation MU OFDM Resource Allocation Why is it so complicate? Each receiver is assigned a set of allocation parameters Each element is a set includes Transmitter assignment Subchannel assignment at the transmitter Bit/power assignment at the subchannel Nonlinear Integer Programming Nonlinear programming optimization of inter-dependent N tran N rec N subc variables! Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

23 Resource Allocation MU OFDM Resource Allocation Why is it so complicate? Each receiver is assigned a set of allocation parameters Each element is a set includes Transmitter assignment Subchannel assignment at the transmitter Bit/power assignment at the subchannel Nonlinear Integer Programming Nonlinear programming optimization of inter-dependent N tran N rec N subc variables! Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

24 Proposed Three-Step Resource Allocation Algorithm The proposed solution is divided into three sequential steps 1 Single transmitter allocation by the highest channel gain. Other transmitters are either: Reused Interfere with other receivers Has is insignificant small gain 2 Subchannel allocation by greedy algorithm User with the least allocated bit-rate chooses the best available subchannel Power is assumed equally distributed between all active subchannels 3 Bit-and-power allocation of each transmitter independently Well-established algorithms The interference is assumed as constant Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

25 Proposed Three-Step Resource Allocation Algorithm The proposed solution is divided into three sequential steps 1 Single transmitter allocation by the highest channel gain. Other transmitters are either: Reused Interfere with other receivers Has is insignificant small gain 2 Subchannel allocation by greedy algorithm User with the least allocated bit-rate chooses the best available subchannel Power is assumed equally distributed between all active subchannels 3 Bit-and-power allocation of each transmitter independently Well-established algorithms The interference is assumed as constant Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

26 Proposed Three-Step Resource Allocation Algorithm The proposed solution is divided into three sequential steps 1 Single transmitter allocation by the highest channel gain. Other transmitters are either: Reused Interfere with other receivers Has is insignificant small gain 2 Subchannel allocation by greedy algorithm User with the least allocated bit-rate chooses the best available subchannel Power is assumed equally distributed between all active subchannels 3 Bit-and-power allocation of each transmitter independently Well-established algorithms The interference is assumed as constant Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

27 Simulation Results Expected 3 gain for 80m 2 room 5 m 7 m 2 m 2 m 2 m 5 m 2 m 2 m 1.5 m 1.5 m 7 m 2 m (a) 1.5 m 9 m (b) 2 m 2 m 2 m 2 m 1.5 m 9 m 2 m 2 m 1.5 m (c) Gain over TDMA-DMT [ ] Conf. (a) Conf. (b) Conf. (c) M (number of receivers) D. Bykhovsky and S. Arnon, Multiple-access resource allocation in visible light communication systems, Journal of Lightwave Technology, 32(8), , Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

28 Summary The scalability of VLC in large rooms can be significantly improved The scalability improvement is obtained by resource allocation Resource allocation may be used to provide QoS/fairness between users Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

29 Summary The scalability of VLC in large rooms can be significantly improved The scalability improvement is obtained by resource allocation Resource allocation may be used to provide QoS/fairness between users Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

30 Summary The scalability of VLC in large rooms can be significantly improved The scalability improvement is obtained by resource allocation Resource allocation may be used to provide QoS/fairness between users Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12

31 Summary The scalability of VLC in large rooms can be significantly improved The scalability improvement is obtained by resource allocation Resource allocation may be used to provide QoS/fairness between users Dima Bykhovsky & Shlomi Arnon (BGU) VLC in MU Environment ICIS / 12