ETSI ETS 300 230 ed.2 (1996-11)
Radio Equipment and Systems (RES); Land mobile service; Binary Interchange of Information and Signalling (BIIS) at 1 200 bit/s (BIIS 1 200)
Radio Equipment and Systems (RES); Land mobile service; Binary Interchange of Information and Signalling (BIIS) at 1 200 bit/s (BIIS 1 200)
RE/RES-02-18
Radijska oprema in sistemi (RES) - Storitev kopenskih mobilnih komunikacij - Izmenjava binarnih podatkov in signalizacije s 1200 biti/s
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-1998
Radijska oprema in sistemi (RES) - Storitev kopenskih mobilnih komunikacij -
Izmenjava binarnih podatkov in signalizacije s 1200 biti/s
Radio Equipment and Systems (RES); Land mobile service; Binary Interchange of
Information and Signalling (BIIS) at 1 200 bit/s (BIIS 1 200)
Ta slovenski standard je istoveten z: ETS 300 230 Edition 2
ICS:
33.060.20 Sprejemna in oddajna Receiving and transmitting
oprema equipment
33.070.01 Mobilni servisi na splošno Mobile services in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN ETS 300 230
TELECOMMUNICATION November 1996
STANDARD Second Edition
Source: ETSI TC-RES Reference: DI/RES-02-18
ICS: 33.060.20 33.060.50
Key words: BIIS, data, mobile, protocol, radio, signalling
Radio Equipment and Systems (RES);
Land mobile service;
Binary Interchange of Information and Signalling (BIIS)
at 1 200 bit/s (BIIS 1 200)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
Copyright Notification:
No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1996. All rights reserved.
Page 2
ETS 300 230: November 1996
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.
Page 3
ETS 300 230: November 1996
Contents
Foreword .9
1 Scope.11
2 Normative references.11
3 Definitions, symbols and abbreviations .11
3.1 Definitions.11
3.2 Symbols .13
3.3 Abbreviations .14
4 System architecture.14
4.1 General network configuration .15
4.2 Addressing.15
4.3 Usage of repeaters.16
5 Basic system definitions.16
5.1 Modulation method .16
5.1.1 Subcarrier modulation .16
5.1.2 Frequency deviation.16
5.2 Transmission format .16
5.3 Link establishment time.17
5.4 Bit synchronization.17
5.5 Block synchronization.17
5.5.1 Normal block synchronization.17
5.5.2 Optional bit and block synchronization .17
5.6 Codewords.18
5.6.1 Redundancy.18
5.6.2 Optional data protection for error correction .19
5.7 Hang-over bit .19
5.8 Signalling cycle.19
6 Services and facilities.21
6.1 Selective calls .21
6.1.1 Individual call.21
6.1.2 Group call.21
6.1.3 Broadcast call .21
6.2 Call priority levels .21
6.2.1 Normal call.21
6.2.2 Priority call.22
6.2.3 Emergency call.22
6.3 Call management.22
6.3.1 Acknowledgements.22
6.3.1.1 Automatic acknowledgement.22
6.3.1.2 Emergency acknowledgement.22
6.3.1.3 Informative acknowledgements .22
6.3.1.4 Invalid call acknowledgement.22
6.3.2 Manual response.22
6.3.3 Call cancellation.22
6.3.4 Emergency reset .22
6.3.5 Repeater access .23
6.4 Telephone access .23
6.4.1 PABX access.23
6.4.2 PSTN access .23
Page 4
ETS 300 230: November 1996
6.5 Special functions.23
6.5.1 Request to call back .23
6.5.2 Channel control.23
6.5.3 Mobile enable/disable.23
6.5.4 Status transmission.23
6.5.5 Data transmission.23
6.5.6 System control .23
6.6 Identification.24
7 Codeword and block definition .24
7.1 Address block .24
7.1.1 General.24
7.1.2 Concatenated codewords.24
7.1.3 Normal address mode.25
7.1.4 External address mode .25
7.2 Operating mode characteristic.25
7.2.1 Category definitions .26
7.2.2 System functions .26
7.2.2.1 Emergency reset.26
7.2.2.2 Cancel.26
7.2.2.3 Clear down.26
7.2.2.4 Maintenance Identification.27
7.2.2.5 Transmitter key on .27
7.2.2.6 Transmitter key off.27
7.2.2.7 Repeater on .27
7.2.2.8 Repeater off.27
7.2.3 Call messages.27
7.2.3.1 Emergency radio call.27
7.2.3.2 Priority radio call .27
7.2.3.3 Normal radio call.28
7.2.3.4 Telephone call.28
7.2.3.5 Broadcast radio call .28
7.2.3.6 Request to call back.28
7.2.3.7 Manual response.28
7.2.3.8 External addressing.28
7.2.4 Acknowledgements.29
7.2.4.1 Emergency acknowledgement.29
7.2.4.2 Repeat acknowledgement.29
7.2.4.3 General acknowledgement.29
7.2.4.4 Absent/unavailable acknowledgement.29
7.2.4.5 Busy acknowledgement.29
7.2.4.6 Call back acknowledgement.30
7.2.4.7 Intermediate acknowledgement.30
7.2.4.8 Reject acknowledgement.30
7.2.5 Special functions.30
7.2.5.1 System control.30
7.2.5.2 Short data transfer.30
7.2.5.3 Dialogue data transfer .31
7.2.5.4 Change channel .31
7.2.5.5 Vote now.31
7.2.5.6 Status request .31
7.2.5.7 Mobile enable .31
7.2.5.8 Mobile disable.31
7.2.6 Status transfer.32
7.2.7 Reserved category .32
7.2.8 Custom functions .32
8 Message procedures .32
8.1 Normal or priority radio call procedure.32
8.2 Broadcast call procedure .33
Page 5
ETS 300 230: November 1996
8.3 Emergency call procedure.33
8.4 Manual response procedure.34
8.5 Call cancellation procedure.34
8.6 Repeater access procedure.35
8.7 Telephone call procedure.35
8.8 Call back request procedure.36
8.9 Change channel procedure.36
8.10 Mobile enable and mobile disable procedure.36
8.11 Status transfer procedure .37
8.12 Short data transfer procedure .37
9 Channel access protocol and occupation rules .38
9.1 Channel access.38
9.2 Retry procedure.39
9.3 Reversion time .39
10 Data protocol .39
10.1 Dialogue protocol services and facilities .40
10.1.1 Acknowledged point-to-point information transfer .40
10.1.2 Acknowledged broadcast information transfer.40
10.1.3 Unacknowledged information transfer.40
10.2 Data transmission structure.40
10.3 Elements of the control block.41
10.3.1 Data terminal sub-address, ADR.41
10.3.2 Command/Response bit, C/R .41
10.3.3 Control field (CONT) .41
10.3.3.1 Sequence numbers, N(R) and N(S).42
10.3.3.2 Poll and final bit, P/F .42
10.3.3.3 Supervisory and modifier function bits, S and M.43
10.3.4 PARAMETER field.43
10.4 I-frames.43
10.5 S-frames .44
10.5.1 Receive Ready (RR) command/response .44
10.5.2 Receive Not Ready (RNR) command/response .44
10.5.3 Reject (REJ) command/response.45
10.5.4 Selective reject (SREJ) command/response .45
10.6 U-frames .46
10.6.1 Set Asynchronous Balanced Mode (SABM) command .46
10.6.2 Disconnect (DISC) command.46
10.6.3 Un-numbered Acknowledgement (UA) response.46
10.6.4 Frame reject (FRMR) response.46
10.6.5 Disconnected Mode (DM) response.47
10.6.6 Un-numbered Information (UI) command.47
10.6.7 Set Group Mode (SGM) command .48
10.7 Data compression .48
11 Definition of the data transfer protocol.49
11.1 Data link set-up phase .49
11.1.1 Point-to-point link set-up.49
11.1.2 Group link set-up.50
11.2 Data transfer phase.50
11.2.1 Transmission of I-frames.50
11.2.1.1 Transmission of I-frames on a point-to-point connection.50
11.2.1.2 Transmission of I-frames on a group connection.50
11.2.2 Reception confirmation.51
11.2.2.1 Point-to-point reception confirmation.51
11.2.2.2 Group reception confirmation.51
11.2.3 Checkpointing.52
11.2.4 Recovery by time control.52
11.2.4.1 Point-to-point time control.52
Page 6
ETS 300 230: November 1996
11.2.4.2 Group time control .52
11.2.5 Reception of I-frames .52
11.2.5.1 Ready-to-receive state.52
11.2.5.2 Not-ready-to-receive state.53
11.3 Resetting phase .53
11.4 Transfer termination phase.53
11.4.1 Point-to-point link termination .53
11.4.2 Group link termination .53
12 Channel access protocol and occupation rules for data transmission.54
12.1 Channel access for data transmission .54
12.2 Retry procedure .54
Annex A (normative): Values of system parameters.55
Annex B (normative): The Radix 40 data compression method.56
Annex C (normative): Hexadecimal digit coding.59
Annex D (normative): Regional Code .60
Annex E (normative): OMC coding.62
Annex F (informative): Examples of channel access and occupation rules.63
F.1 Message duration.63
F.2 Successful transmission of a message .63
F.3 Unsuccessful transmission of a message and repetition .63
F.4 Channel access with time intervals .64
F.5 Channel access for data transmission with time intervals.64
Annex G (informative): System-terminal interface.65
G.1 Interface for data terminal equipment .65
G.2 Procedure for the system-terminal interface.65
G.2.1 Asynchronous procedure 1 (CR/LF) .66
G.2.2 Asynchronous procedure 2 (STX/ETX) .66
G.2.3 Synchronous procedure 1 (STX/ETX).66
G.2.4 Synchronous procedure 2 (HDLC).66
Annex H (informative): Examples for the data dialogue procedure.67
H.1 Test algorithm for the validity of N(R) .67
H.2 State transition table of the data dialogue procedure .67
H.2.1 State table for miscellaneous inputs .68
H.2.2 State table for commands received.69
H.2.3 State table for responses received.70
Annex J (informative): Verification of the integrity of the I-frames .72
Annex K (informative): Using forward error correction.73
Annex L (informative): Examples of using the COM field.75
Page 7
ETS 300 230: November 1996
Annex M (informative): Bibliography.76
History .77
Page 8
ETS 300 230: November 1996
Blank page
Page 9
ETS 300 230: November 1996
Foreword
This European Telecommunication Standard (ETS) has been produced by the Radio Equipment and
Systems (RES) Technical Committee of the European Telecommunications Standards Institute (ETSI).
The binary signalling procedure described in this ETS is an alternative to existing calling systems such as
single-tone, multitone, subaudio and double-tone.
Every I-ETS and ETS prepared by ETSI is a voluntary standard. This ETS contains text concerning
conformance testing of the equipment to which it relates. This text should be considered as guidance only
and does not make this ETS mandatory.
Transposition dates
Date of adoption of this ETS: 8 November 1996
Date of latest announcement of this ETS (doa): 28 February 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 August 1997
Date of withdrawal of any conflicting National Standard (dow): 31 August 1997
Page 10
ETS 300 230: November 1996
Blank page
Page 11
ETS 300 230: November 1996
1 Scope
This ETS describes a binary signalling and data transmission system for private radio equipment operating
at 1 200 bit/s using indirect modulation.
This ETS applies to systems operating on either shared, or exclusive, channels.
According to national regulations of various countries, Public Switched Telephone Network (PSTN) access
and data transmission can be subject to licensing. The channel access protocol and occupation rules can
also be a matter for licensing, depending on the different national regulations.
This ETS permits the addition, if necessary, of supplementary signalling, either sub-audio, multitone, or
binary, as appropriate, to permit primary and secondary paging to be used. This ETS does not attempt to
define the protocols necessary for such supplementary signalling.
Where parameters relating to the radio environment are specified, reference should be made to the
appropriate clauses of ETS 300 113 [3]. However, selective calls according to this ETS can be
implemented in equipment fulfilling I-ETS 300 219 [2] (that is messages of categories 0, 2, 4, 5 and
messages of category 1 and functions 0, 1 and 2 as defined in subclause 7.2 of this ETS).
2 Normative references
This ETS incorporates by dated or undated reference, provisions from other publications. These normative
references are quoted at the appropriate places in the text and the publications are listed hereafter. For
dated references subsequent amendments to or revisions of any of these publications apply to this ETS
only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies.
[1] ISO 4335 (1987): "Information processing systems - Data communication -
High-level data link control elements of procedures".
[2] I-ETS 300 219: "Radio Equipment and Systems (RES); Land Mobile Service;
Technical characteristics and test conditions for radio equipment, transmitting
signals to initiate a specific response in the receiver".
[3] ETS 300 113: "Radio Equipment and Systems (RES) Land mobile service;
Technical characteristics and test conditions for radio equipment intended for the
transmission of data (and speech) and having an antenna connector".
[4] ITU-T Recommendation T.50: "International Alphabet No. 5".
[5] ISO 3309 (1991): "Information technology - Telecommunications and information
exchange between systems - High-level data link control (HDLC) procedures -
Frame structure".
[6] ETS 300 471: "Radio Equipment and Systems (RES) Land mobile service;
Access protocol and occupation rules for the transmission of data in shared
channels".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
address: Information which consists of a Regional Code, a common address part, and an individual
number or a group number.
Page 12
ETS 300 230: November 1996
address block: A block containing addresses. The first block of a transmission is always an address
block. It can be followed by other address blocks (subclause 7.1).
address codeword: A 64-bit codeword. The first 48 bits contain the information, the remaining 16 bits
contain the redundancy for the data protection. The first codeword of a transmission is always an address
codeword that can be followed by others. The transmitter address, the receiver address and the function
of the message are transmitted in the address codeword.
block: The smallest quantity of information that is exchanged over the radio channels according to this
ETS. It can correspond to the transmission of either a "codeword" or an "encoded codeword".
call set-up: A complete information exchange between two or more stations, including the transmission of
one or more messages.
codeword: A word correctly coded according to this ETS. It contains 48 bits of information. These bits are
protected by 16 bits of redundancy, producing a total of 64 bits.
common address: A common part for an individual transmitter and individual receiver address.
data block: A block intended for the transmission of information. The data blocks can only follow address
blocks in a transmission.
data codeword: A 64-bit codeword. The first 48 bits contain the information, the remaining 16 bits contain
the redundancy for the data protection. The data codewords follows the address codewords. Data
codewords are assigned to the transmission of any information.
encoded codeword: The 64 bits of a codeword which have been encoded with the convolutional code,
producing a total of 128 bits.
external addressing: An addressing format in which the individual transmitter and receiver address are
binary coded within 12 bits using the normal addressing mode. The complete transmitter address with its
individual and common part is located in the first address codeword. The complete receiver address with
its individual and common part is located in the second address codeword.
group address: An address shared by several stations. The group number can be any number within the
normal addressing capacity of 12 bits. The group numbers are user specific.
I-frame: See subclause 10.4.
individual address: The address of a station, which is unique within the network. Each station has an
individual address.
message: The contiguous transmission of a codeword sequence consisting of an address codeword which
may be followed by other address codewords and by one or several data codewords.
normal addressing: An addressing format in which the individual transmitter and receiver address are
binary coded within 12 bits and completely located in the address codeword not being followed by other
address codewords.
reserved: Fields within codewords which are intended for a future designation. Reserved fields are
intended for the values specified in the protocol.
S-frame: See subclause 10.5.
signalling cycle: A sequence of several messages having the same function which are separated by bit
and block synchronization.
sub-address: The individual address of a terminal equipment if a station has connections to more than one
terminal. This is defined for data transmission only.
Page 13
ETS 300 230: November 1996
telephone call: A message which allows dialling into telephone networks. The entire telephone number is
transmitted within concatenated codewords.
transmission: The information transmitted in between the "power on" and "power off" period of a
particular transmitter, which may include blocks and/or speech.
U-frame: See subclause 10.6.
3.2 Symbols
For the purposes of this ETS, the following symbols apply:
dTT The maximum time during which an acknowledgement or reply may be sent after
expiry of TT.
H Hexadecimal notation, e.g. 2A is equal to 42 decimal.
H
K The maximum number of unacknowledged sequentially numbered I-frames at a
specific time.
N1 The highest number of data blocks which may be transmitted within an I-frame.
N2 The maximum number of retransmissions of an I-frame after the expiry of the
time control T1.
NA The number of acknowledgement repetitions within a signalling cycle.
ND The maximum number of data blocks used for short data transfer.
NM The number of message repetitions within a signalling cycle.
NR The maximum number of retries of a message if an acknowledgement is not
received.
T1F The fixed part of the retry waiting time T1 after whose expiry a repetition of a
frame is initiated.
T1I The increment part of the retry waiting time T1 after whose expiry a repetition of
a frame is initiated.
T3 The time after which a receiving station automatically exits the group mode.
TAC The time waiting for an acknowledgement after whose expiry a repetition of the
message is initiated.
TAD The time waiting for a response after whose expiry a repetition of a frame is
initiated.
TC The maximum waiting time to access a channel.
TF The time after which a call is cleared if an Radio Frequency (RF) carrier is lost.
TI The time following an intermediate acknowledgement after which further
signalling is expected.
TOF The fixed part of the observation time TO after whose expiry the channel may be
occupied.
TOI The increment part of the observation time TO after whose expiry the channel
may be occupied.
Page 14
ETS 300 230: November 1996
TRV The maximum time between the last bit of a message and keying of the
transmitter by the answering station.
TS1 The transmit state time within an emergency cycle.
TS2 The receive state time within an emergency cycle.
TS3 The idle state time within an emergency cycle.
TT The maximum transmission time during which a station may access the channel
for ongoing data packet transmissions.
TV The maximum duration time of a call after which the call is automatically cleared.
TWF The fixed part of the retry waiting time TW after whose expiry a repetition of the
message is initiated.
TWI The increment part of the retry waiting time TW after whose expiry a repetition
of the message is initiated.
3.3 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
ADM Asynchronous Disconnected Mode
ABM Asynchronous Balanced Mode
BS Base Station
DTE Data Terminal Equipment
FCS Frame Check Sequence
FEC Forward Error Correction
GM Group Mode
HDLC High-level Data Link Control
IA5 International Alphabet No. 5 [4]
LET Link Establishment Time
LSB Least Significant bit
MS Mobile Station
MSB Most Significant bit
PABX Private Automatic Branch eXchange
PSTN Public Switched Telephone Network
RF Radio Frequency
RX Receiver
TE Terminal Equipment
TX Transmitter
4 System architecture
This ETS may be implemented only in parts. Where parts, or options, of this ETS are implemented, the
requirements of this ETS shall be met. Conversely the bits specified in this ETS for options which are not
implemented, shall not be used for any other purposes.
Fields that have been reserved to provide for future extensions to this ETS shall not be used. Finally, fields
have been defined as free for custom specific applications and are not further defined in this ETS.
Page 15
ETS 300 230: November 1996
4.1 General network configuration
One example of the network configuration is represented in figure 1, but other configurations are possible.
For this example the network contains four main interfaces. The Man-Machine Interface (MMI), the
Terminal-Mobile Interface (TE/MS), and the System-Terminal Interface (SC/TE) are specified by the
system designer. In this ETS, only the Air Interface (AI) is defined. The recommended System-Terminal
Interface (SC/TE) is outlined in annex D. The information to be transmitted is transferred to the connected
terminals or gateways for processing.
PABX
PRIVATE GATEW AY
< > < > PSTN
TE MS BS SC PUBLIC GATEW AY
TE
SC/TE
TE
TE MS < > < > BS SC TE
TE
TE/MS
SC/TE
TE MS RE
< > < >
TE
MS <
>
TE
A I
MMI TE/MS
NOTE: RE: Repeater
TE: Terminal Equipment
MMI: Man-Machine Interface
MS: Mobile Station
TE/MS: Terminal-Mobile Interface
BS: Base Station
AI: Air Interface
SC: System Control
SC/TE: System-Terminal Interface
Figure 1: Example of a network configuration
4.2 Addressing
All units of the network (mobile stations, base stations, repeaters) have one or several addresses.
These addresses include individual addresses, group call addresses and common addresses to all units of
a network.
Where several data terminals are connected to the same station, sub-addresses may be used.
Page 16
ETS 300 230: November 1996
When gateways are used, additional information is needed to identify destination terminals.
4.3 Usage of repeaters
Systems implemented according to this ETS may include repeaters. If repeaters are used, data can be
repeated in one of the three following ways:
- full transparency;
- bit by bit regeneration;
- message error correction and repetition of a transmission.
Each repeater can be addressed using its individual address.
5 Basic system definitions
This clause describes the basic system definitions for the signalling and data transmission system.
In the following figures, the transmitted bit stream is always shown with bit 1, the Most Significant
bit (MSB), transmitted first.
Where data bytes or characters are transmitted, the MSB shall also be transmitted first. This differs from
most line applications where the Least Significant bit (LSB) is sent first.
5.1 Modulation method
5.1.1 Subcarrier modulation
The binary data transmission is based on subcarrier modulation. Fast Frequency Shift Keying (FFSK) at
1 200 bit/s is used. The transition between bits are made at the zero crossing points of the subcarrier.
The modulation parameters are represented in table 1.
Table 1: Modulation parameters
Transmission speed 1 200 bit/s ± 0,01 %
Binary 0 1 800 Hz ± 0,01 %
Binary 1 1 200 Hz ± 0,01 %
5.1.2 Frequency deviation
The nominal frequency deviation should be as shown in table 2. Under all test and operating conditions the
deviation shall be within ± 2 dB of these values.
Table 2: Frequency deviation
Channel Frequency deviation (kHz)
spacing(kHz)
with pre-emphasis (+ 6 dB / octave) without
pre-emphasis
binary 0 binary 1 binary 0 and 1
12,5 1,8 1,25 1,5
20,0 2,9 2,00 2,4
25,0 3,6 2,50 3,0
5.2 Transmission format
The system is able to transmit signalling and data packets consisting of an address codeword and
concatenated codewords. Concatenated codewords can be address codewords or one or more data
codewords. They begin directly after the last check bit of the preceding codeword.
Page 17
ETS 300 230: November 1996
The first codeword of a message is always an address codeword. This codeword specifies the receiver
and the transmitter. The first codeword may be followed by other address codewords for further
addressing.
The format of a signalling or data transmission is represented in figure 2.
Bit-no. 1 ……. n
LET BITSYNC BLCSYNC codewords H
NOTE: LET: Link Establishment Time
BITSYNC: Bit Synchronization
BLCSYNC: Block Synchronization
H: Hang-Over bit
Figure 2: Transmission format
5.3 Link establishment time
Transmissions shall be preceded by a Link Establishment Time (LET) within which a transmission,
preferably unmodulated, at not less than 90 % of maximum power shall take place. The duration of the
LET shall be defined on a system by system basis.
5.4 Bit synchronization
The binary transmission shall begin with a bit reversal 1010.10 so that the receiver data demodulator can
be synchronized to the transmitted signal. The normal bit synchronization (BITSYNC) consists of 16 bits
and ends with a binary 0. An optional bit synchronization is defined in subclause 5.5.2.
5.5 Block synchronization
5.5.1 Normal block synchronization
The block synchronization (BLCSYNC) marks the beginning of the codeword framing. It consists of 16 bits.
The bit pattern and the hexadecimal equivalent are represented in figure 3.
Bit-no. 1 ……. 16
Bit pattern 1 0 1 1 0 1 0 0 0 0 1 1 0 0 1 1
HEX-value B 4 3 3
Figure 3: Block synchronization
If the block synchronization is not received correctly, the blocks that follow shall not be decoded.
The autocorrelation properties of the BLCSYNC are calculated with respect to its corresponding
BITSYNC.
5.5.2 Optional bit and block synchronization
It is possible to protect all codewords with a Forward Error Correction (FEC). If the codewords are
overlaid by a FEC code this is indicated by the inverse bit and block synchronization. The bit
synchronization ends with a binary 1. The bit pattern and the hexadecimal equivalent of the inverse block
synchronization are represented in figure 4.
Bit-no. 1 ……. 16
Bit pattern 0 1 0 0 1 0 1 1 1 1 0 0 1 1 0 0
HEX-value 4 B C C
Figure 4: Optional block synchronization
If the block synchronization is not received correctly, the blocks that follow shall not be decoded.
Page 18
ETS 300 230: November 1996
The autocorrelation properties of the BLCSYNC are calculated with respect to its corresponding
BITSYNC.
5.6 Codewords
The codewords have a constant length of 64 bits. 48 bits contain the information and 16 bits contain the
redundancy for the data protection. The structure is represented in figure 5.
Bit-no. 1.48 49.64
I N F O R M A T I O N redundancy
Length 48 16
Figure 5: Codeword structure
5.6.1 Redundancy
The redundancy comprises 16 bits and shall be used for error detection. Error corrections may also be
performed. The check bits are calculated in three steps:
- the first 15 check bits originate from a (63,48) cyclic block code. The 48 information bits represent
the coefficients of a polynomial. This polynomial is divided modulo 2 by the following generating
polynomial:
15 14 13 11 4 2
x + x + x + x + x + x + 1
14 0
The first 15 check bits correspond to the coefficients of the terms from x to x in the remaining
polynomial after the complete division;
- the 15th check bit is then inverted;
- finally, a parity bit is appended to the 63 bit block to provide an even parity of the complete 64 bit
block.
The error control properties of the codewords, using a hard decision decoding, can be one of the following:
- detection of all odd number of errors, any random errors up to 5, and any error burst up to
length 16;
- correction of any single bit error and detection of any random errors up to 4, and any error burst up
to length 11;
- correction of any two errors and detection of any random errors up to 3, and any error burst up to
length 4;
- correction of any single error burst up to length 5.
Page 19
ETS 300 230: November 1996
5.6.2 Optional data protection for error correction
In order to enable increased error correction, the 64 bits of each codeword may optionally be encoded
with a (20,10) convolutional code. Using the "tail-biting" procedure the encoded codeword has a length of
128 bits. The code is defined by the parity
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...