ANSI INCITS 371 1-2003 for Information Technology Real Time Locating Systems (RTLS) Part 1 2 4-GHz Air Interface Protocol.pdf

1、American National StandardDeveloped byANSI INCITS 371.1-2003for Information Technology Real Time Locating Systems (RTLS) Part 1: 2.4-GHz Air Interface ProtocolANSIINCITS371.1-2003ANSIINCITS 371.1-2003American National Standardfor Information Technology Real Time Locating Systems (RTLS) Part 1: 2.4-G

2、Hz Air Interface ProtocolSecretariatInformation Technology Industry Council (ITI)Approved July 25, 2003American National Standards Institute, Inc.AbstractThis standard defines one of the two air interfaces with multiple subcomponents for a class of Real TimeLocating Systems (RTLS) for use in asset m

3、anagement. This standard is intended to allow for compatibil-ity and to encourage interoperability of products for the growing RTLS market.Approval of an American National Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met b

4、y the standards developer.Consensus is established when, in the judgement of the ANSI Board ofStandards Review, substantial agreement has been reached by directly andmaterially affected interests. Substantial agreement means much more thana simple majority, but not necessarily unanimity. Consensus r

5、equires that allviews and objections be considered, and that a concerted effort be madetowards their resolution.The use of American National Standards is completely voluntary; theirexistence does not in any respect preclude anyone, whether he has approvedthe standards or not, from manufacturing, mar

6、keting, purchasing, or usingproducts, processes, or procedures not conforming to the standards.The American National Standards Institute does not develop standards andwill in no circumstances give an interpretation of any American NationalStandard. Moreover, no person shall have the right or authori

7、ty to issue aninterpretation of an American National Standard in the name of the AmericanNational Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose name appears on the titlepage of this standard.CAUTION NOTICE: This American National Standard ma

8、y be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be taken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of American National Standards mayreceive current information on all standards by calling or writing th

9、e AmericanNational Standards Institute.American National StandardPublished byAmerican National Standards Institute, Inc.25 West 43rd Street, New York, NY 10036Copyright 2003 by Information Technology Industry Council (ITI)All rights reserved.No part of this publication may be reproduced in anyform,

10、in an electronic retrieval system or otherwise,without prior written permission of ITI, 1250 Eye Street NW, Washington, DC 20005. Printed in the United States of AmericaCAUTION: The developers of this standard have requested that holders of patents that may be re-quired for the implementation of the

11、 standard disclose such patents to the publisher. However, nei-ther the developers nor the publisher have undertaken a patent search in order to identify which, ifany, patents may apply to this standard. As of the date of publication of this standard, followingcalls for the identification of patents

12、 that may be required for the implementation of the standard,notice of one or more such claims has been received. By publication of this standard, no positionis taken with respect to the validity of this claim or of any rights in connection therewith. The knownpatent holder(s) has (have), however, f

13、iled a statement of willingness to grant a license underthese rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to ob-tain such a license. Details may be obtained from the publisher. No further patent search is con-ducted by the developer or publisher in respect

14、to any standard it processes. No representation ismade or implied that this is the only license that may be required to avoid infringement in the use ofthis standard.iContentsPageForeword iiIntroduction v1 Scope and Purpose 12 Normative References 23 Terms and Definitions. 24 General Information 55

15、Air Interface Protocol Specifications. 6Tables1 DSSS Link Parameters. 42 DSSS 56-Bit Message Format . 103 DSSS 72-Bit Message Format . 114 DSSS 88-Bit Message Format . 115 DSSS 152-Bit Message Format . 11Figures1 Example Differential Encoding Circuit 62 RTLS Transmitter PN Generator 73 RTLS Transmit

16、ter Data Encoding and Transmission Process . 74 DSSS Air Interface Protocol . 85 RTLS Transmitter State Diagram . 9iiForeword (This foreword is not part of American National Standard ANSI INCITS 371.1-2003.)ANSI INCITS 371.1-2003 is one of a series of standards for Real Time Locating Sys-tems (RTLS)

17、 that provides in real-time the physical location and the tracking of as-sets, human resources, or any other category of mobile items. This series ofstandards is intended to foster compatibility and interoperability of RTLS. There arethree standards in this series. Two airwave interface protocols ar

18、e specified: one isdefined to provide a high-precision system operating at 2.4 GHz and a second to pro-vide a lower-precision system operating at 433 MHz. A single Application Program-ming Interface (API) is defined that provides a unifying interface for either of the twoairwave interface protocols.

19、Requests for interpretation, suggestions for improvement or addenda, or defect re-ports are welcome. They should be sent to InterNational Committee for InformationTechnology Standards (INCITS), ITI, 1250 Eye Street, NW, Suite 200, Washington,DC 20005.This standard was processed and approved for subm

20、ittal to ANSI by INCITS. Com-mittee approval of this standard does not necessarily imply that all committee mem-bers voted for its approval. At the time it approved this standard, INCITS had thefollowing members:Karen Higginbottom, ChairJennifer Garner, SecretaryOrganization Represented Name of Repr

21、esentativeApple Computer, Inc. David Michael Wanda Cox (Alt.)Farance, Inc. Frank Farance Richard Lutz (Alt.)Hewlett-Packard Company. Karen Higginbottom Scott Jameson (Alt.)Steve Mills (Alt.)EIA Edward Mikoski, Jr. Judith Anderson (Alt.)Suan Hoyler (Alt.)IBM Corporation . Ronald F. Silletti Institute

22、 for Certification of Computer Professionals Kenneth M. Zemrowski Thomas Kurihara (Alt.)IEEE . Judith Gorman Richard Holleman (Alt.)Robert Pritchard (Alt.)Intel Corporation. Gregory Kisor Dave Thewlis (Alt.)Microsoft Corporation . Mike Ksar Joseph Zajaczkowski (Alt.)National Institute of Standards l

23、ess than 512 bits. 3.2.2.8 upconvert. A technique to change a baseband signal to a higher frequency modulated signal for transmission. 3.3 Physical Layer Parameters For this standard, the following parameter definitions apply. These parameters are referenced by both the parameter number and the para

24、meter name. 3.3.1 RTLS Transmitter DSSS Link Parameters Table 1 DSSS Link Parameters Parameter number Parameter name Description D 1a Operating frequency range 24002483.5 MHz D 1b Operating frequency accuracy 25 ppm maximum D 1c Center frequency 2441.750 MHz D 2 Occupied channel bandwidth 60 MHz D 3

25、 Transmit power Class 1: 10 dBm EIRP max. Class 2: Max per FCC part 15 D 4 Spurious emission, out of band Within FCC part 15 specification D 5 Modulation BPSK Direct Sequence Spread Spectrum (DSSS) D 6 Data encoding Differentially encoded D 7 Data bit rate 59.7 kbit/sec D 8 Bit error rate 0.001% D 9

26、 PN chip rate 30.521875 MHz +/- 25 ppm D 10 PN code length 511 D 11 PN spread code 0x1CB D 12 Data packet lengths Option 1: 56 bits Option 2: 72 bits Option 3: 88 bits Option 4: 152 bits D 13a Message CRC polynomial G(x)=X11 + X3 + X2 + X + 1 D 13b CRC polynomial initialized value 0x001 D 14a Blink

27、interval Programmable, 5 sec. minimum D 14b Blink interval randomization 638 milliseconds minimum D 15a Number of sub-blinks Programmable, 1 - 8 D 15b Sub-blink interval randomization 125 milliseconds 15 milliseconds D 16 Maximum Frequency Drift +/- 2 ppm over the duration of the entire message D 17

28、a Phase Accuracy 0.5 radians within any 33 microsecond period D 17b Phase Noise 15 degrees when the noise is integrated from 100hz to 100khz ANSI INCITS 371.1-2003 5 4 General Information 4.1 Frequency Range This standard addresses Real Time Locating Systems (RTLS) operating in the 2.400 to 2.4835 G

29、Hz fre-quencies. 4.2 Interface Definitions ANSI INCITS 371.1: 2.4 GHz Air Interface Protocol ANSI INCITS 371.2: 433 MHz Air Interface Protocol ANSI INCITS 371.3: The Common API for Interface between either 2.4 GHz or 433 MHz Band RTLS and Application Programs 4.3 Minimum Features The minimum feature

30、 set shall include: 2-dimensional location RTLS transmitters that autonomously generate a direct sequence spread spectrum radio fre-quency beacon Transmission at a power level that can facilitate reception at ranges of 300 meters open-field separation between the transmitter and receiver RTLS transm

31、itters that are fully compliant with US radio frequency regulatory requirements Nominal location data provided by the RTLS that is within a 3-meter radius of the actual location of the transmitting RTLS transmitter when tested in open field. RF transmissions that are low power and that are compatibl

32、e with, shall not interfere (not cause any measurable difference in throughput) and co-exist with existing standardized IEEE 802.11 wireless communication networks and systems compliant with ANSI INCITS 256. 4.4 Compliance Requirements To be fully compliant with this standard, Real Time Locating Sys

33、tems (RTLS) shall also comply with ANSI INCITS 371.3. 4.5 Manufacturer Tag ID The manufacturers tag identification number identifies a particular manufacturer and consists of 16 bits. A manufacturer may have more than one ID number. As reported from the RTLS Server to the API, the first 16 bits are

34、designated for the manufacturers identification number. As reported from the Data Link Layer to the API, the remaining 16 bits establish a numbering system made unique by the initial manufac-turer ID number. The manufacturers identification number is a registration maintained by INCITS T20. ANSI INC

35、ITS 371.1-2003 6 5 Air Interface Protocol Specifications ANSI INCITS 371.1 defines the 2.400- to 2.4835-GHz RTLS spread-spectrum transmissions and the command/data level air interface communication protocols. These protocols facilitate communication be-tween a compliant RTLS transmitter and a compli

36、ant infrastructure. The timing parameters and signal characteristics for the protocols are defined in the physical link specification in clause 5.3. 5.1 Introduction A beacon type RTLS system architecture consists of RTLS transmitters that “blink” a Direct Sequence Spread Spectrum (DSSS) signal and

37、fixed position RTLS readers that receive those signals. The system then determines the x, y location of the RTLS transmitters. Location of tagged assets can be determined with better than 3m accuracy in most environments, indoors and out. Once the location of the RTLS transmitter is determined, the

38、location information and any other information is passed to the host applica-tion. Additionally, an option that provides the ability to transmit telemetry data is defined. 5.2 Functional Description The RTLS transmitter module is typically a compact internally powered radio frequency device that is

39、a component of the RTLS system. The RTLS system is designed to track and locate items with attached RTLS transmitters. Each locatable transmission is a pulse of direct sequence spread spectrum radio sig-nal. The RTLS infrastructure receives these signals, or blinks. The blink is a short ID-only mess

40、age or a longer telemetry message also containing the RTLS transmitters ID. Each transmission also contains a status data word that provides information on the RTLS transmitter configuration, battery status and other data. The RTLS transmitters ID, status data word and location are provided to the h

41、ost by the RTLS In-frastructure. Multiple RTLS transmitters may be present in typical installations allowing a large number of items to be tracked and located in real time. Anticollision synchronization protocols are not required. Each “blink” is comprised of multiple sub-blinks. The sub-blinks are

42、part of a multiple level antiinterference system; time diversity, spatial diversity, proc-essing gain. The combination of these multiple sub-blinks, multiple receiving antennas and spread spec-trum correlation also allow multiple RTLS transmitters to blink simultaneously and still be received. The R

43、TLS transmitter data shall be binary encoded with the MSB (Most Significant Bit) transmitted first in all messages. It is differentially encoded using the example circuit of Figure 1. The output of the encoder shall be initialized to 1. It shall be exclusively ORd with the output of the PN (Pseudo N

44、oise) generator, modulated using a BPSK (Bi-Phase Shift Keyed) format and upconverted using a single sideband upcon-verter. The signal is then amplified and transmitted to the RTLS infrastructure. QQSETCLRDData InData OutClockFigure 1 Example Differential Encoding Circuit An example of the RTLS Tran

45、smitter PN Generator is shown below in Figure 2. ANSI INCITS 371.1-2003 7 QQSETCLRDQQSETCLRDQQSETCLRDQQSETCLRDQQSETCLRDQQSETCLRDQQSETCLRDQQSETCLRDQQSETCLRDCBPN-Code1PN GeneratorOutputD1 D2 D3 D4 D5 D6 D7 D8 D9Figure 2 RTLS Transmitter PN Generator The data encoding and transmission process is shown

46、below in Figure 3. Differentially Encode DataExclusive (XOR) DifferentiallyEncoded Data with output ofPN GeneratorBPSK ModulateFrequency translate/Upconvert to 2.44175 GHzAmplify signal and transmit tosystemFigure 3 RTLS Transmitter Data Encoding and Transmission Process ANSI INCITS 371.1-2003 8 The

47、 format of the Direct Sequence Spread Spectrum (DSSS) transmission from the RTLS transmitter is shown in Figure 4. Each DSSS transmission from the RTLS transmitter contains a “blink” packet contain-ing N sub-blinks. Each set of sub-blinks can be one of four message lengths. All sub-blinks within a “

48、blink” shall be identical to provide time diversity. Each sub-blink includes the RTLS transmitters 32-bit ID, 4-bits of status data, CRC (Cyclical Redundancy Check) data and optional telemetry data depending on the type of message. The “blink” packet occurs at the beginning of the blink interval. Su

49、b-blinks shall be separated by an interval, which is not user configurable. The number of sub-blinks per blink and the blink interval are configurable. Figure 4 DSSS Air Interface Protocol Three classes of DSSS blinks are defined; Timed Interval Blink (TIB), Exciter Blink (EXB), and Event Blink (EB). TIBs transmit at a preprogrammed rate. Event blinks should be caused by a switch event or exter-nal stimulus. A state diagram showing the different operational states of the RTLS Transmitter is shown below in Figure 5. Bli