Implementation of HA-QL Code

HA-QL (Hidden Asynchronous Quick-Link) is a hidden modulation mode among Screen-2-Camera operating modes within the IEEE 802.15.7-2018 Optical Wireless Communication standard. An interesting feature of HA-QL is that it allows for controlling the peak-to-peak amplitude of the intensity modulation, from a visible code to a hidden code. The HA-QL Code Project is cleaned, well-packed and documented. Technical …

Software-defined Configuration method for OCC Systems

The purpose of the post is to specify the PIB attributes for configuring a particular OCC PHY mode. Any OCC PHY mode is co-existing with the others and recognizable by a specific receiver once the PIBs are specified. The configuration of PHY-PIB attributes is software-defined (App-based). Without using PHY-frame overhead, the App-based configuration is communication …

PPDU: PHY frame format for S2-PSK & HS-PSK

This post reviews the design of the Physical-layer Packet Data Unit (PPDU) for S2-PSK and HS-PSK operating modes within PHY IV of IEEE 802.15.7m. The general structure of PPDU for all OCC Operating modes is illustrated in Figure 1. SHR: Synchronization Header PHR: Physical-Layer Header HCS: Header Check Sequence PSDU: PHY service data unit "Use of over-the-air PHY …

HS-PSK: High-rate transfer over RoI(s)

HS-PSK is an operating mode being standardized at IEEE 802.15.7m. This post describes what it is for and how it operates. Figure 1 illustrates an example in which an Rx can select the link properly for an intended usage. The link setup procedure is solved by the RoI-Signaling waveform, while this high-rate waveform is additionally …

S2-PSK: A choice for RoI-Signaling

S2-PSK is an operating mode being standardized at IEEE 802.15.7m. This post describes what it is for and how it operates.   Technical Considerations for a RoI-signaling Waveform Even though RoI-signaling mode has a very low data rate, it is indispensable to the OCC system operating in a challenging condition such as V2X. The general …

PPDU: PHY frame format for CM-FSK & C-OOK

This post reviews the design of the Physical-layer Packet Data Unit (PPDU) for CM-FSK  and C-OOK operating modes within PHY V of IEEE 802.15.7m. For a detailed explanation of how these modes operate, please visit the previous CM-FSM post and the previous C-OOK post. The comparison between these modulation schemes for rolling shutter OCC was discussed …

PPDU: PHY frame format for Screen Modulation Systems (A-QL & HA-QL)

This post reviews the design of the Physical-layer Packet Data Unit (PPDU) for A-QL and HA-QL operating modes within PHY IV Screen modulation of IEEE 802.15.7m. For implementation, the Data Frame Format is crucial; each operating mode has its packet format and the format specification has its reason. At least, time is spent on optimizing …

HA-QL: Part 2 – Hiding data into Screen using Wavelet Transform

HA-QL (Hidden Asynchronous Quick-Link) is a hidden modulation mode among Screen-2-Camera operating modes those are being standardized at IEEE 802.15.7m. The previous post explains the principle to generate a hidden code on the screen using an additional intensity modulator after the bit-intensity mapper. However, the modulation of screen intensity dramatically degrades the communication performance. In …

HA-QL: Part 1- Intensity modulation for Hidden Screen Code

HA-QL (Hidden Asynchronous Quick-Link) is a hidden modulation mode among Screen-2-Camera operating modes those are being standardized at IEEE 802.15.7m. This post describes what it is for and how it operates. Introduction The name Hidden A-QL briefly describes how it operates. The mapping from bits into the screen cells during modulation in HA-QL shall follow …

A-QL: Part 2 -BER Measurement

A-QL (Asynchronous Quick-Link) is a Screen-2-Camera operating mode being standardized at the IEEE 802.15.7m. This post introduces the BER measurement method and the performance of A-QL system. See this video demo for the BER measurement scenario: https://www.youtube.com/watch?v=Mkq2lYKzQsQ   Experimental Setup The scenario for measuring BER is illustrated in Figure 1. The bit rate is measured …

A-QL: Part 1- Introduction of Reliable Screen-Camera Communication

A-QL (Asynchronous Quick-Link) is a Screen-2-Camera operating mode being standardized at IEEE 802.15.7m. This post describes what it is for and how it operates. Figure 1 - Example of color code displaying with video on a screen And before we start talking about A-QL system, a short demo of it is here: https://www.youtube.com/watch?v=B6uBTSdh44Y Introduction The …

Rolling shutter OCC: Communication distance vs Data rate Trade-off

The classification of OCC technologies has been given. Being a part of non-flicker modulation series, with the vast usage of rolling shutter cameras in the camera market, the use of rolling shutter cameras in OCC systems takes advantage of the high sampling rate of the rolling shutter mechanism, which sequentially exposes pixel lines to the …

C-OOK: Customizing OOK for Optical Camera Communication

C-OOK stands for Camera ON-OFF Keying, is also an operating mode being standardized in IEEE 802.15.7m. This post reviews the operation of this mode and highlights its characteristics. See video demo 1 (Manchester coded for Rolling shutter OCC): https://www.youtube.com/watch?v=tMaR7B5M3QI See video demo 2 (4B6B coded for Rolling shutter OCC): https://www.youtube.com/watch?v=wPbeZZxEMVY C-OOK for OCC and its …

FEC: Generation of Reed-Solomon and Convolutional Code

Reed Solomon and Convolutional Code are chosen for IEEE 802.15.7-2011 and IEEE 802.15.7m implementation. In this post, we will review the generation of the codes and simulate their performance for comparison. Reed Solomon  Systematic RS codes are used for FEC (typically outer FEC) with GF(16), generated by the polynomial x4+x+1. The generators for the RS(n, …

What is Optical Region-of-Interest Signaling?

In the context of a safety assistance communication-based solution, OWC is a strong candidate for delivering the V2V communication power to cars. It is realized that the LED lighting is quipped to car mandatorily, meanwhile, a camera is considered as one of the indispensable sensors for car vision. The existence of supportive infrastructure enables the …

PHY modes within IEEE 802.15.7m draft – a quick review

PHY operating modes  The latest IEEE 802.15.7m draft standard (until Aug. 2018) is on the Sponsor Balloting recirculation. This version has updated a lot in compared to the previous version before LiFi modes are moved to new task group under IEEE 802.15. A list of operating modes between two drafts is a good start. Notation …