1、 Reference numberECMA-123:2010Ecma International 2010ECMA-397 1stEdition / December 2010 Short Distance Visible Light Communication (SDVLC) COPYRIGHT PROTECTED DOCUMENT Ecma International 2010 Ecma International 2010 iContents Page 1 Scope 1 2 Conformance . 1 3 Normative references 1 4 Terms and def
2、initions . 1 5 Conventions and notations 5 6 General . 5 7 Physical Layer . 6 8 Transmitter and Receiver Block Diagram . 7 8.1 Transmitter to Receiver Link 7 8.2 Data Encoding . 7 8.2.1 8B10 Data Encoding 7 8.2.2 2B4B Data Encoding . 7 8.3 Modulation . 8 8.4 Bit Order . 8 9 Frame Formats . 8 9.1 Fra
3、me Structure overview 8 9.2 Frame Structure Detail 10 9.2.1 Start Indicator Structure . 10 9.2.2 Control Header Structure 11 9.3 MAC PDU Structure . 13 9.3.1 MAC Header . 13 9.3.2 Payload . 14 9.3.3 Payload CRC 15 9.4 Visible Frame . 15 9.4.1 Visible Pattern 15 9.5 Cyclic Redundancy Check (CRC) 16 1
4、0 Connection Procedure 16 11 Association Operation Messages 17 11.1 Association Request (AS-REQ) . 17 11.2 Association Response (AS-RSP) . 18 11.3 Association Acknowledge (AS-ACK) 18 11.4 Disassociation Request (DAS-REQ) 19 11.5 Disassociation Response (DAS-RSP) . 19 11.6 Disassociation Acknowledge
5、(DAS-ACK) . 20 12 Data Burst Modes Operation 20 12.1 Periodic Burst Mode 20 12.1.1 Burst Request Message (BR-REQ) 21 12.1.2 Burst Response Message (BR-RSP) . 22 12.2 Aperiodic Burst Mode . 24 12.2.1 Aperiodic Burst Request Message (ABR-REQ) 25 12.2.2 Aperiodic Burst Response Message (ABR-RSP) . 26 1
6、3 Data Encoding Change . 28 13.1 ENC-REQ (Data Encoding Change Request) 29 13.2 ENC-RSP (Data Encoding Change Response) . 29 ii Ecma International 2010Introduction SDVLC uses visible light LEDs for data communication. In most cases, LEDs with the primary purpose of illumination will take on the seco
7、ndary purpose of acting as a digital data communication source; in other cases the LEDs primary purpose will be data communication while the secondary purpose will be to communicate visible status to the user. With the extension of the application of LEDs from the primary purpose of illumination to
8、the secondary purpose of data communication, VLC (Visible Light Communication) can be also applied to short range data communication. With SDVLC, “what you see is what you send”. One possible application of SDVLC is high speed mobile to mobile communication. This Ecma Standard has been adopted by th
9、e General Assembly of December 2010. Ecma International 2010 iii“DISCLAIMER This document and possible translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published, and distri
10、buted, in whole or in part, without restriction of any kind, provided that the above copyright notice and this section are included on all such copies and derivative works. However, this document itself may not be modified in any way, including by removing the copyright notice or references to Ecma
11、International, except as needed for the purpose of developing any document or deliverable produced by Ecma International (in which case the rules applied to copyrights must be followed) or as required to translate it into languages other than English. The limited permissions granted above are perpet
12、ual and will not be revoked by Ecma International or its successors or assigns. This document and the information contained herein is provided on an “AS IS“ basis and ECMA INTERNATIONAL DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORM
13、ATION HEREIN WILL NOT INFRINGE ANY OWNERSHIP RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.“ iv Ecma International 2010Short Distance Visible Light Communication (SDVLC) 1 Scope This Ecma Standard specifies a PHY and MAC for communication of up to 10 cm dist
14、ance with an fmof 120 MHz using visual light with the wavelength between 380 and 780 nm. In addition it specifies human detectable brightness control that is independent from the modulation for the data transfer. 2 Conformance Conformant implementations: have both a Transmitter and a Receiver. use 8
15、B10B encoding and may use 2B4B encoding. use an fmof 120 MHz as specified in 8.3. 3 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the
16、referenced document (including any amendments) applies. ECMA-340, Near Field Communication - Interface and Protocol (NFCIP-1) ISO/IEC 7498-1, Information technology Open Systems Interconnection Basic Reference Model Part 1: The Basic Model ISO/IEC 14165-251, Information technology - Fibre Channel -
17、Part 251: Framing and Signaling (FC-FS) ITU-T Z.100, Specification and description language (SDL) RFC 791, Internet Protocol - DARPA Internet Program Protocol Specification 4 Terms and definitions For the purposes of this document, the following terms, definitions and abbreviations apply, in additio
18、n to those in ISO/IEC 7498-1. 4.1 Ack Acknowledge 4.2 AK Ack/Nack Ecma International 2010 14.3 ABR-REQ Aperiodic Burst Request 4.4 ABR-RSP Aperiodic Burst Response 4.5 AS-ACK Association Acknowledge 4.6 AS-REQ Association Request 4.7 AS-RSP Association Response 4.8 Burst Master Burst scheduler 4.9 B
19、urst Slave Burst schedule follower 4.10 BR-REQ Burst Request 4.11 BR-RSP Burst Response 4.12 BS Burst Start 4.13 BWS Burst Window Size 4.14 CHC Control Header CRC 4.15 CRC Cyclic Redundancy Check 4.16 DAS-ACK Disassociation Acknowledge 4.17 DAS-REQ Disassociation Request 2 Ecma International 20104.1
20、8 DAS-RSP Disassociation Response 4.19 DCC-REQ Duty Cycle Change Request 4.20 DCC-RSP Duty Cycle Change Response 4.21 dectet group of 10 bits (cf. octet) 4.22 DER Data Encoding Response 4.23 Disassociatee recipient of a DAS-REQ 4.24 Disassociator initiator of a disassociation 4.25 DQWS Data Quiet Wi
21、ndow Size 4.26 ENC Data Encoding 4.27 FL Frame Length 4.28 fmFrequency of modulation clock that changes the optical output signal 4.29 FT Frame Type 4.30 Initiator initiator of an association 4.31 LEN Length 4.32 MF MAC Flag Ecma International 2010 34.33 MHC MAC Header CRC 4.34 MM Management Message
22、 4.35 Nack Negative Acknowledge 4.36 OOK On-Off Keying 4.37 OP Operation 4.38 PL Payload Length 4.39 PDU Protocol Data Unit ISO/IEC 7498-1 4.40 PSN PDU Sequence Number 4.41 RC Response Code 4.42 Recipient receiver of a frame 4.43 RFU Reserved for Future Use 4.44 RID Recipient ID 4.45 RVF Recipient V
23、F 4.46 SDL Specification and Description Language ITU-T Z.100 4.47 SDU Service Data Unit ISO/IEC 7498-1 4 Ecma International 20104.48 SDVLC Short Distance Visible Light Communication 4.49 Sender sender of a frame 4.50 SI Start Indicator 4.51 SID Sender ID 4.52 SMF Supported Modulation Frequencies 4.
24、53 Target recipient of an AS-REQ 4.54 VF Visible Frame 4.55 VFA VF Mode Stop Approve 4.56 VFR VF Mode Stop Request 4.57 VLC Visible Light Communication 5 Conventions and notations The following conventions and notations apply in this document unless otherwise stated. The setting of bits is denoted b
25、y ZERO or ONE. An individual bit in a field is identified by a numerical subscript of the field name, where for numeric values the least significant bit of the value is assigned to the bit with subscript 0. (xxxxxxx)b denotes a sequence of binary digits. 6 General All RFU bits shall be set to 0 by t
26、he Sender and ignored by the Recipient. Unless otherwise stated, all RFU values shall be ignored by the Recipient. Ecma International 2010 57 Physical Layer Figure 1 illustrates the basic model of the SDVLC Transmitter and Receiver. A SDVLC Transmitter shall have an optical output with a minimum pea
27、k irradiance of 3 W/m2between 380 nm and 780 nm over an area of at least 1,0 cm x 1,0 cm at a distance of 10 cm, and a 10% to 90% rise time trand fall time tfof at most 3,0 ns, illustrated in Figure 2. The SDVLC Transmitter shall have a maximum off irradiance of 1 mW/m2. A SDVLC Receiver shall have
28、an optical sensitivity from 380 nm to 780 nm and from 0 cm to at least 10 cm from a SDVLC Transmitter. Figure 1 SDVLC Transmitter and Receiver Relative Irradiance =(Irradiance Minimum Waveform Irradiance) / (Maximum Waveform Irradiance Minimum Waveform Irradiance)100%90%10%0%Timetrtfm x tbn x tbm, n
29、 are positive integersFigure 2 SDVLC Modulation Waveform 6 Ecma International 20108 Transmitter and Receiver Block Diagram 8.1 Transmitter to Receiver Link In Figure 3, the modular structures of SDVLC system are shown. When data is to be transmitted, the data is encoded by the Data Encoding block. I
30、n the Modulation block, encoded data is used to modulate the optical output. The optical output is then transmitted to the Receiver. The Demodulation block of the Receiver demodulates the optical signal. The demodulated signal is then decoded by the Data Decoding block. OpticalSignalOutputOpticalSig
31、nalInputTransmitter DataReceiverDataModulationDemodulationData EncodingData DecodingFigure 3 Transmitter and Receiver block diagram 8.2 Data Encoding SDVLC supports two different data encoding schemes. One of the data encoding schemes (8B/10B) allows the maximum data throughput but has a fixed optic
32、al link duty cycle of 50%. The other data encoding scheme (2B4B) has a lower data throughput but allows optical link duty cycles other than 50%. 8.2.1 8B10 Data Encoding When using 8B/10B encoding, the SDVLC Transmitter shall use the 8B/10B encoding as specified in ISO/IEC 14165-251. 8.2.2 2B4B Data
33、 Encoding In 2B4B encoding, the SDVLC Transmitter shall encode pairs of data bits into 4 bit symbols by selecting a row of Table 1. Note that which row is selected in Table 1 can be different for each pair of data bits, thus allowing for average duty cycles between 25% and 75%. Table 1 Data Encoding
34、 Data (00)b (01)b (10)b (11)b Encoded Data Duty Cycle 25% (0001)b (0010)b (0100)b (1000)b 50% (0011)b (0110)b (1100)b (1001)b 75% (1110)b (1101)b (1011)b (0111)b Ecma International 2010 78.3 Modulation The modulation of the optical link is On-Off Keying (OOK). SDVLC may support a maximum of 16 diffe
35、rent OOK fm. The fmof 120 MHz is mandatory. The fmshall be at the specified frequency with a relative frequency tolerance of 20 10-4% and a maximum peak jitter of 100 ps. Bit duration time tb(illustrated in Figure 2) is 1/fm. 8.4 Bit Order The least significant bit of each symbol shall be transmitte
36、d first, while the most significant bit of each symbol shall be transmitted last. 9 Frame Formats SDVLC transmissions shall be in the form of a sequence of frames, as shown in Figure 4. Each frame in the sequence is either a Data Frame or a Visible Frame. Figure 4 Frame Sequence 9.1 Frame Structure
37、overview Two frame structures shall be used in SDVLC: a Data Frame structure, as specified in Figure 5, and a Visible Frame structure, as specified in Figure 6. 8 Ecma International 2010Figure 5 Data Frame structure Ecma International 2010 9Figure 6 Visible Frame structure The choice of which frame
38、structure to use may depend on the communication link status. When the communication link between Transmitter and Receiver is established with good alignment, the Data Frame structure is used for data communication. The Visible Frame structure is used to control the visible aspect of the communicati
39、on beam to notify the user of a link failure (such as misalignment between the two devices) when the communication link between Transmitter and Receiver is not established. The decision of which frame structure to use may be made using the information in the control header, and when the communicatio
40、n link fails or becomes misaligned, the frame structure type may be changed. The Visible Frame structure may be also used to cause the devices to show a beam while not transmitting data, thus making visible the communication link. 9.2 Frame Structure Detail The frame structure for SDVLC shall consis
41、t of Start Indicator, Control Header, and either a series of one or more MAC PDUs or a Visible Pattern. 9.2.1 Start Indicator Structure The Start Indicator structure shall consist of Preamble_1 and Preamble_2 as specified below. Preamble_1 shall be (10)b repeated 800 times. Preamble_1 may be used by
42、 the Recipient to synchronize the receive data clock to the received data. For 2B4B encoding, Preamble_2 shall be (11110000)b repeated five times. For 8B/10B encoding, Preamble 2 shall be the 8B/10B K28.1 symbol repeated four times. The Recipient shall check Preamble_2 field, and if Preamble_2 is no
43、t correct the Recipient shall consider a frame to not be started. Preamble_2 may be used by the Recipient for symbol synchronization to denote the end of the Preamble_1 and the start of PHY data. 10 Ecma International 20109.2.2 Control Header Structure After the symbol synchronization process using
44、the Start Indicator completes, the control information shall be transmitted in the Control Header. The format of the Control Header is specified in Figure 7, and the contents of the Control Header are specified in Table 2. Reserved values shall not be used by a Sender. If a Recipient receives a Cont
45、rol Header that uses a reserved value it shall discard the Frame. Figure 7 Control Header structure Ecma International 2010 11Table 2 Control Header contents Field Name Description Sender ID Sender ID Recipient ID Recipient ID Frame Type 0: Data frame 1: Visible frame 2-15: RFU RFU RFU Frame Length
46、Length of Data Frame or Visible Frame, from the start of the Control Header through the end of the Frame, in bits. Ack/Nack 0: No Ack/Nack 1: Nack 2: Ack 3-15: RFU Recipient VF 1: Recipient may transmit visible frames 0: Recipient shall not transmit visible frames RFU RFU Management Message See 9.2.
47、2.1 Control Header CRC 16-bit CRC of the Control Header from the Sender ID field through the MAC Management Message field; see 9.5 for the specification of the 16-bit CRC. The Recipient shall calculate the 16-bit CRC upon reception and compare the result to the value in this field; if the comparison
48、 fails the frame shall be discarded. The Recipient shall send the status of receiving data to the Sender through the Ack/Nack bit assignments. When the Sender finishes transmitting the last bit of the frame, it shall start a timeout timer. If the Sender does not receive an Ack for a transmitted fram
49、e by the time the timeout timer reaches T_ack, it shall either retransmit the frame or drop the association. If the Sender receives a Nack for a transmitted frame, it shall either retransmit the frame or drop the association. T_ack shall be 10 ms. 9.2.2.1 Management Message Management messages start with an 8-bit Management Message Type field. Table 3 below shows the defined management message types in the Management Message Type field. When the Management Message Type is “0” or RFU, the Management Message P
