Hong Kong
+ 852-36202131

Product Proposal

Introduction & Field Background

Li-Fi advantages over Wi-Fi

  • More Capacity (10000 times spectrum)
  • Efficiency
  • Availability
  • Security

Li-Fi Transmitter : LED

  • Easily modulated
  • Fast Switching
  • Transmit thousands of data streams in parallel

Li-Fi Receiver options

  • LED reverse bias
  • Photo diode (PD) : more sensitive than LED
  • Camera mobile phone

CMOS Image Sensors (CIS)

  • Main Components : PD (capture light), Color Filter (RGB) and Micro Lens (gather light)
  • Global Shutter vs. Rolling Shutter : Using rolling Shutter to increase data rate
  • APS (Active Pixel Sensor) vs. DVS (Differential Vision Sensor) : Using DVS to increase frame rate

Li-Fi case study using CIS

  • Samsung Galaxy Nexus Camera ( Res. : 1920×1080 & Scanning time: 23ms)
  • Potential Bit Rate =(1080 row)/(8 row for separation between bits) ×1/23ms ×3bit (RGB) ≈ 15 kbps
  • Limits of bit rate: ADC conversion time & readout circuit time

Good Future Background in the area

  • Test Setup on visible light communication (VLC)
  • Data Rate = 10Mbit/sec
  • Distance = 150cm
  • Increasing LED bandwidth by pole cancelling

Variable Bandwidth TIA and Limiting Amplifier for Maximum Sensitivity in Free Space Optical Links

  • This receiver consists of a pre-current amplifier, TIA, BW control unit, offset cancellation and a limiting amplifier.
  • The receiver is designed for the data rates of 16Mbps to 1Gbps between the distances of 100m to 1km.
  • A total transimpedance gain and input referred noise of 117dB and 5.2pA/√?? was obtained. The total power consumption is 113mW.
  • High sensitivity and the ability to steer the bandwidth to compensate for the channel variations loss
  • A novel idea for a new clock data recovery architecture was proposed which can lock to the data while smoothly doubling the data rate without losing any of the information.

Optical ICs

  • Transimpedance Amplifier (TIA)
  • Up to 10.7Gbps operation for OC-192/STM-64, 10GE, and OC-192 with FEC
  • Small signal transimpedance of 700 ohms (Single ended)
  • Low power consumption: 53mW
  • Standard 0.13 µm CMOS technology
Optical ICs

  • TIA/PA Combination
  • 9.2 GHz typical BW
  • Three functional modes: TIA / PA / COMBO
  • 91 dB gain with 50 ohm output impedance
  • Standard 0.13 µm CMOS technology
  • Gain adjustable in three modes : LA / VGA / ICVGA
10Gbps Laser Diode/ Modulator Driver (LDMD)

    • 80mA digitally programmable modulation current
    • Standard 0.13 µm CMOS technology
    • Less than 25ps rise and fall times (20% -80%)
    • Very low power of less than 60mW
      • (excluding bias and modulation currents)
      • reduces heat generation and enables very small form factor design
    • On-chip detector allows automatic diode end of life detection

Existing Projects:

  • Generalized computer driven RGB LED driver test setup allowing various data formats and rates to be sent
  • App development for mobile phone LED control
  • A test bench for reception of VLC data comprising of PD+TIA/PA+CDR to characterize various sources (Up to 10Mbit/sec)

Other projects Good Future could do for you:

  • App development on Android & IOS platforms
  • Characterization of various brand mobile phones for maximum LED driving rate capability
  • Characterization of the existing brand mobile phones for maximum camera data rates
  • Characterization of the camera modules for the mobile phones that has a physically separate media module

Feasibility report and existing technology analysis

Review of key technologies in VLC (2010-2018)

  • Laser vs. LED device power and speed limits
    • Pre-emphasis filters
    • Mach Zehnder vs. Laser
    • Extinction Ratio
  • Laser/LED driver circuits
    • Temperature and aging compensation
    • Scalable driver
  • Existing PD device limits
  • PD made in CMOS vs. advance heterogeneous semiconductors
  • TIA/PA and SerDes state of the art
  • Clock-Data recovery (CDR) technologies in CMOS
  • Camera Chip technological advances
    • Basic camera chip architectures
    • Camera fps for mobile phones with slow motion
    • Techniques for Giga rate fps
  • Wi-Fi modules and chipsets
    • 802.11b, a and g
    • Advanced 802.11 with beam steering and Giga rate data
  • Proposal for technology and chipset development for VLC and Wi-Fi combo module on existing mobile phones for advanced high rate data transmission including higher security.