CA2269526A1 - Method for the transmission of user data in a hybrid telecommunication system especially an "isdn ?? dect specific rll/wll" system - Google Patents
Method for the transmission of user data in a hybrid telecommunication system especially an "isdn ?? dect specific rll/wll" system Download PDFInfo
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- CA2269526A1 CA2269526A1 CA002269526A CA2269526A CA2269526A1 CA 2269526 A1 CA2269526 A1 CA 2269526A1 CA 002269526 A CA002269526 A CA 002269526A CA 2269526 A CA2269526 A CA 2269526A CA 2269526 A1 CA2269526 A1 CA 2269526A1
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- telecommunications
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- dect
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/08—Access point devices
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0041—Arrangements at the transmitter end
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
- H04Q11/0435—Details
- H04Q11/0457—Connection protocols
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13098—Mobile subscriber
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13166—Fault prevention
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13209—ISDN
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13216—Code signals, frame structure
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13292—Time division multiplexing, TDM
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13298—Local loop systems, access network
Abstract
In order to improve transmission of user data in a hybrid telecommunication system, especially an "ISDN ?? DECT specific RLL/WLL" system, user data is transferred according to a user data transmission protocol, wherein a data transmission redundancy arising from the difference between a first user data transmission capacity of an ISDN system (640 bit of an ISDN-B-channel) and a third user data transmission capacity of a DECT/ISDN intermediate system (800 bit of a DECT Double Slot Format) is used to avoid delays in transmission occurring in addition to system induced transmission delays compromising error free transmission of data, while providing fully secured data transmission.
Description
_ _ .,tn pp i' : a.. b . ~ ~~ ; , , .1 ,t~~C"r~
m.
Method for Transmission of User Data in a Hybrid Tele communication System, Especially an "ISDN<-->DECT Specific RLL/WLL" System In information systems with an information transmission link between a source of information and an information recipient, in order to transmit and process information, use is made of transmitting and receiving equipment in which:
1) the information processing and information transmission can be carried on in a preferred transmission direction (simplex operation) or in both transmission directions (duplex operation), 2) the information processing is analog or digital, 3) the information transmission on long-distance transmission links is either by wire or wireless, based on diverse information transmission methods such as frequency division multiple access (FDMA), time division multiple access (TDMA) and/or code division multiple access (CDMA), for example, according to radio standards such as DECT, GSM, WACS, or PACS, IS-54, PHS, PDC, etc.[see IEEE Communications Magazine, January 1995, pp. 50-57; D.D. Falconer et al, "Time Division Multiple Access for Wireless Personal Communications"].
"Information" is a generic expression that covers both the content (information) and the physical representation of the signal (signal). Despite the identical content of a message, various kinds of signal may occur. Thus, for example, information that relates to a single object may be transmitted (1) as an image, (2) as a spoken word, (3) as a written word, (4) as an encoded word or image The type of transmission used for (1), (2), and (3) above is normally characterized by continuous (analog) signals, whereas in the case of (4) above, the type of transmission is characterized by intermittent signals (e. g., pulses, digital signals).
Proceeding from this general definition of an information system, the present invention relates to a method and a telecommunications bus for transmission of continuous and/or intermittent data flows in a hybrid telecommunications system, in particular an ISDN-<-->DECT-specific RLL/WLL telecommunications system as defined in the preamble to Patent Claim 1.
Hybrid telecommunications systems are, for example, different--(wireless or wire-based)--information systems that incorporate telecommunications sub-systems.
Representing the large number of hybrid telecommuni-cations systems, and based on publications such as Nach-richtentechnik Elektronik, Berlin 45 (1995), No.l, pp. 21-23, and No. 3, pp. 29-30, as well as IEEE Colloquium 1993, 173; (1993), pp. 29/1 - 29/7; W.Hing, F.Halsall, "Cordless Access to the ISDN
basic rate service," based on a DIIS (DECT/ISDN Intermediate Service) as described in ETSI-Publikation prETS 300xxx, Version 1.10, September 1996, Figure 1 shows an Integrated Services Digital Network<-->Radio in the Local Loop/Wireless in the Local Loop (ISDN-<-->DECT specific RLL/WLL) telecommunications system with an ISDN-Telecommunications Sub-System (I-TTS) [see Nach-richtentechnik Elektronik, Berlin 41-43, Parts 1-10:
Part 1: (1991), No. 3, pp. 99-102 Part 2: (1991), No. 4, pp. 138-143 Part 3: (1991), No. 5, pp. 179-182, and No. 6, pp. 219-220 Part 4: (1991), No. 6, pp. 220-222, and (1992), No. 1, pp. 19-20 Part 5: (1992), No. 2, pp. 59-62, and (1992), No. 3, pp. 99-102 Part 6: (1992), No. 4, pp. 150-153 Part 7: (1992), No. 6, pp. 238-241 Part 8: (1993), No. 1, pp. 29-33 Part 9: (1993), No. 2, pp. 95-97, and (1993), No. 3, pp. 129-135 Part 10: (1993) No. 4, pp. 187-190]
and a DECT-specific RLL/WLL Telecommunications Sub-System (RW
TTS).
It is preferred that the DECT/ISDN Intermediate System (DIIS) or the RLL/WLL Telecommunications Sub-System (RW-TTS) be based in a Digital Enhanced (formerly: European) Cordless Telecommunication/Generic Access Profile (DECT/GAP) System (DGS);
see:
(1): Nachrichtentechnik Elektronik 42 (1992), Jan/Feb, No. 1, Berlin, Germany: U.Pilger, "Struktur des DECT Standard"
[Structure of the DECT Standard], pp. 23-29 in conjunction with ETSI Publication ETX 300175-1...9, October 1992;
(2): Telcom Report 16 (1993), No. 1, J.H. Koch, "Digitaler Komfort fur schnurlose Telekommunikation - DECT Standard eroffnet neue Nutzungsgebiete [Digital Convenience for Cordless Tele-communications - DECT Standard is Opening Up New Areas of Use], pp. 26 and 27;
(3): tec 2/93 - Das technische Magazin von Ascom [The Technical Magazine from Ascom]: "Wege zur universellen mobilen Telekommunikation" [Ways to Universal Mobile Telecommunication], pp. 35-42;
(4): Philips Telecommunications Review, Vol. 49, No. 3, Sept, 1991, R.J. Mulder: "DECT, a universal cordless access system";
m.
Method for Transmission of User Data in a Hybrid Tele communication System, Especially an "ISDN<-->DECT Specific RLL/WLL" System In information systems with an information transmission link between a source of information and an information recipient, in order to transmit and process information, use is made of transmitting and receiving equipment in which:
1) the information processing and information transmission can be carried on in a preferred transmission direction (simplex operation) or in both transmission directions (duplex operation), 2) the information processing is analog or digital, 3) the information transmission on long-distance transmission links is either by wire or wireless, based on diverse information transmission methods such as frequency division multiple access (FDMA), time division multiple access (TDMA) and/or code division multiple access (CDMA), for example, according to radio standards such as DECT, GSM, WACS, or PACS, IS-54, PHS, PDC, etc.[see IEEE Communications Magazine, January 1995, pp. 50-57; D.D. Falconer et al, "Time Division Multiple Access for Wireless Personal Communications"].
"Information" is a generic expression that covers both the content (information) and the physical representation of the signal (signal). Despite the identical content of a message, various kinds of signal may occur. Thus, for example, information that relates to a single object may be transmitted (1) as an image, (2) as a spoken word, (3) as a written word, (4) as an encoded word or image The type of transmission used for (1), (2), and (3) above is normally characterized by continuous (analog) signals, whereas in the case of (4) above, the type of transmission is characterized by intermittent signals (e. g., pulses, digital signals).
Proceeding from this general definition of an information system, the present invention relates to a method and a telecommunications bus for transmission of continuous and/or intermittent data flows in a hybrid telecommunications system, in particular an ISDN-<-->DECT-specific RLL/WLL telecommunications system as defined in the preamble to Patent Claim 1.
Hybrid telecommunications systems are, for example, different--(wireless or wire-based)--information systems that incorporate telecommunications sub-systems.
Representing the large number of hybrid telecommuni-cations systems, and based on publications such as Nach-richtentechnik Elektronik, Berlin 45 (1995), No.l, pp. 21-23, and No. 3, pp. 29-30, as well as IEEE Colloquium 1993, 173; (1993), pp. 29/1 - 29/7; W.Hing, F.Halsall, "Cordless Access to the ISDN
basic rate service," based on a DIIS (DECT/ISDN Intermediate Service) as described in ETSI-Publikation prETS 300xxx, Version 1.10, September 1996, Figure 1 shows an Integrated Services Digital Network<-->Radio in the Local Loop/Wireless in the Local Loop (ISDN-<-->DECT specific RLL/WLL) telecommunications system with an ISDN-Telecommunications Sub-System (I-TTS) [see Nach-richtentechnik Elektronik, Berlin 41-43, Parts 1-10:
Part 1: (1991), No. 3, pp. 99-102 Part 2: (1991), No. 4, pp. 138-143 Part 3: (1991), No. 5, pp. 179-182, and No. 6, pp. 219-220 Part 4: (1991), No. 6, pp. 220-222, and (1992), No. 1, pp. 19-20 Part 5: (1992), No. 2, pp. 59-62, and (1992), No. 3, pp. 99-102 Part 6: (1992), No. 4, pp. 150-153 Part 7: (1992), No. 6, pp. 238-241 Part 8: (1993), No. 1, pp. 29-33 Part 9: (1993), No. 2, pp. 95-97, and (1993), No. 3, pp. 129-135 Part 10: (1993) No. 4, pp. 187-190]
and a DECT-specific RLL/WLL Telecommunications Sub-System (RW
TTS).
It is preferred that the DECT/ISDN Intermediate System (DIIS) or the RLL/WLL Telecommunications Sub-System (RW-TTS) be based in a Digital Enhanced (formerly: European) Cordless Telecommunication/Generic Access Profile (DECT/GAP) System (DGS);
see:
(1): Nachrichtentechnik Elektronik 42 (1992), Jan/Feb, No. 1, Berlin, Germany: U.Pilger, "Struktur des DECT Standard"
[Structure of the DECT Standard], pp. 23-29 in conjunction with ETSI Publication ETX 300175-1...9, October 1992;
(2): Telcom Report 16 (1993), No. 1, J.H. Koch, "Digitaler Komfort fur schnurlose Telekommunikation - DECT Standard eroffnet neue Nutzungsgebiete [Digital Convenience for Cordless Tele-communications - DECT Standard is Opening Up New Areas of Use], pp. 26 and 27;
(3): tec 2/93 - Das technische Magazin von Ascom [The Technical Magazine from Ascom]: "Wege zur universellen mobilen Telekommunikation" [Ways to Universal Mobile Telecommunication], pp. 35-42;
(4): Philips Telecommunications Review, Vol. 49, No. 3, Sept, 1991, R.J. Mulder: "DECT, a universal cordless access system";
(5): W093/21719 (Figure 1 to Figure 3 with the associated description)]. The GAP Standard is a subset of the DECT Standard that is intended to ensure interoperability of the DECT air interface for telephone applications (see ETSI Publication prETS
300444, April 1995).
Alternatively, the DIIS or the RW-TTS can be based in a Group Speciale Mobile or Global System for Mobile communication (GSM) systems see Information Spektrum 14 (1991), June, No. 3, Berlin, Germany; A.Mann: "Der GSM Standard - Grundlage fur digitale europaische Mobilfunknetze" [The GSM Standard - Basis for Digital European Mobile Radio Networks], pp. 137-152). In place of this, within the framework of a hybrid telecommun-ications system, it is also possible that the I-TTS be configured as a GSM system. Furthermore, other possibilities for realizing the DIIS or of the RW-TTS or the I-TTS are the above-discussed systems and future systems that are based on known multiple access methods such as frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA) hybrid multiple access methods formed from these.
The use of radio channels (e. g., DECT channels) in classical wire-based telecommunications systems like ISDN is becoming increasingly important, in particular as viewed against the background of future, alternative network operators who do not possess their own, complete wired-based networks.
Thus, for example, in the case of the RLL/WLL tele-communications sub-system, it is intended to make the RLL/WLL
connection technology available e.g., by tying-in the DECT system (DS) to the ISDN subscriber ISDN services on standard ISDN
buses(see Figure 1).
In the IDRW-TS shown in Figure 1, a telecommunications user (TC) and his terminal endpoint or terminal equipment (TE) are tied into the ISDN world, with the associated services available there, for example by way of a standardized S-bus, the DIIS (first telecommunications sub-system), which is preferably DECT-specific and incorporated in the RW-TSS, an additional, standardized S-bus of the (S-bus), network termination (NT), and a standardized U-bus of the I-TTS (second telecommuni-cations sub-system.
Essentially, the first telecommunications sub-system (DIIS) comprises two telecommunications buses, a DECT-intermediate fixed system (DIFS) telecommunications bus, and a DECT intermediate portable system (DIPS) second tele-communications bus that are connected to each other by way of a DECT air interface. Because of the DIFS quasi-fixed first telecommunications bus, the DIIS first telecommunications sub-s system forms the first local information transmission loop that has been defined above in this connection. The DIFS first telecommunications bus incorporates a radio fixed part (RFP), and inter-working unit IWU1 and interface circuitry INC1, for the S-bus. The second telecommunications bus DIPS incorporates a radio portable part (RPP) and an interworking unit IWU2, and interface circuitry INC2 for the S-bus. The radio fixed part (RFP) and the radio portable part (RPP) form the known DECT/GAP system (DGS).
Based on Nachrictentechnik Elektronik 42 (1992) Jan/Feb No. 1, Berlin, Germany: U.Pilger, "Struktur des DECT Standards"
[Structure of the DECT Standard], pp. 23-29, in conjunction with ETS 300 175-1 " ,9, October 1992, Figure 2 shows the TDMA
structure of a DECT/GAP system. Relative to the multiple-access method, the DECT/GAP system is a hybrid system in which, according to the TDMA principle as in Figure 2, it is possible to transmit radio messages in a predetermined time sequence from the radio fixed part RFP to the radio portable part RPP, and from the radio portable part RPP to the radio fixed part RFP (duplex operation) on ten frequencies in the frequency band between 1.88 and 1.90 Ghz. When this is done, the time sequence is determined by a multi-time frame MZR that occurs every 160 ms and which comprises 16 time frames ZR, each of which has a duration of 10 ms. Separated according to radio fixed part RFP and radio portable part RPP, information that applies to a C, M, N, P, or Q
channel as defined in the DECT standard is transmitted in these time frames ZR. If information for several of these channels is transmitted in one time frame ZR, then the transmission is effected according to a priority schedule, with M>C>N, and P>N.
Each of the 16 time frames ZR of the multi-time frame MZR is further divided into 24 time slots ZS, each of which is of a duration of 417 ~s; of these, 12 time slots ZS (time slots 0...11) are earmarked for transmission in the direction "radio fixed part RFP -> radio part RPP, and a further 12 time slots ZS
(time slots 12...23) are earmarked for transmission in the direction radio portable part RPP->radio fixed part RFP.
According to the DECT Standard, information that is 480 bits long is transmitted in each of these time slots ZS. Of these 480 bits, 32 bits are transmitted in a SYNC field as synchronizing information, and 388 bits are transmitted as user information in a D-field. The remaining 60 bits are transmitted in a Z-field, as additional information, and in a guard-time field, as security information. The 388 bits of the D-field that are transmitted as user information are further subdivided in a 64-bit long A-field, a 320-bit long B-field, and a 4-bit long X-CRC word. The 64-bit long A-field comprises an 8-bit long header, a 40-bit long data set with data for the C, Q, M, N, and F channels, and a 16-bit long A-CRC word. The DECT transmission structure shown in Figure 2 is designated as full-slot format. In addition, a double-slot format is also defined in the DECT Standard (see W093/21719).
Based on the OSI/ISO layered model (see the following):
(1): Information sheets - Deutsche Telekom, Year 48, 2/1995, pp.102-111;
(2): ETSI Publication ETS 300175-1...9, October 1992:
(3): ETSI Publication ETS 300102, February 1992;
(4): ETSI Publication ETS 300125, September 1991 (5) ETSI Publication ETS 300012, April 1992, Figure 3 shows a model of the C level of the IDRW-TS
(ISDN<-->DECT-specific RLL/WLL telecommunications system) that is shown in Figure 1 (see ETSI Publication prETS 300xxx, Version 1.10, September 1996, Chapter 5, Figure 3).
Based on the OSI/ISO layered model (see the following):
(1): Information sheets - Deutsche Telekom, Year 48, 2/1995, pp.102-111;
(2): ETSI Publication ETS 300175-1...9, October 1992;
(3): ETSI Publication ETS 300102, February 1992;
(4): ETSI Publication ETS 300125, September 1991;
(5) ETSI Publication ETS 300012, April 1992, Figure 4 shows a model of the U level, for speech data transmission, of the IDRW-TS (ISDN<-->DECT-specific RLL/WLL
telecommunications system} that is shown in Figure 1 (see ETSI
Publication prETS 300xxx, Version 1.10, September 1996, Chapter 5, Figure 4).
_g_ In the case of the DECT/ISDN intermediate system (DECT/ISDN Protocol Profile) as in Figure 1, it is possible, for example, to make an So connection available to an ISDN subscriber by wireless means by way of a DECT air interface. In this connection, depending on the ISDN-specific service (speech, data, etc.), in each instance a DECT radio channel is set up for the ISDN D-channel (data transmission rate 16 kb/s) and the two ISDN
B-channels (data transmission rate 64 kb/s). Initially, a DECT
traffic bearer in full-slot format, i.e., 320 bit user data per 10 ms or per TDMA frame; data transmission rates of 32 kb/s) is set up for the ISDN D-channel. If ISDN B-channels are required for the ISDN connection, then a DECT traffic bearer in full-slot format (i.e., 320 bits user data per 10 ms or per TDMA frame;
data transmission rages of 32 kb/s) or a DECT traffic bearer in double-slot format (800 bits user date per 10 ms or per TDMA
frame; data transmission rates of 80 kb/s) will be set up for each B-channel, depending on whether speech data or video data is to be transmitted. However, the full-slot format of the ISDN D-channel will only be needed for those times when a very large amount of ISDN signalling data is to be transmitted. Typically, this happens at the start of a connection. From these ISDN
signalling data, one can determine whether or not the ISDN
connection requires ISDN B-channels, and if so, how many.
Accordingly, one or two DECT traffic bearers are set up in double-slot format, or one or two double slots are seized. If the data rate on the ISDN D-channel now falls, the DECT traffic bearer in the full-slot format is dropped and signalling is continued in the A-field of one of the two DECT traffic bearers, in double-slot format. Unfortunately, this is not possible from the start, since the data rate of the ISDN D-channel is higher than that in the A-field of a DECT traffic bearer. For this reason, in the event that it is seen that the data rate in the ISDN D-channel is increasing again, the DECT traffic bearer in the full-slot format is also set up once again for the ISDN D-channel, as required. Using this mechanism, it is intended that the load on the DECT spectrum be minimized by the ISDN D-channel (see German Patent Application 19625142.7). However, if such an ISDN connection is first set up by way of the DECT air interface, each of the ISDN B-channels occupies a DECT double slot (accordingly, 2 of 120 DECT channels), until such time as the connection is dropped once again.
For the transmission of ISDN B-channel data at a data transmission rate of 64 kb/s, for DECT/ISDN intermediate systems as in ETSI Publication prETS 300xxx, Version I.10, September 1996, Chapters 12.3 and 12.4, Annex A.2.1.1 and Annex B.2, and for DECT/ISDN end systems as in ETSI Publication prETS 300434-1, January 1996, Annex B of the Lu7 data service, provision is made such that a combination of an Automatic Repeat Request (ARQ) process, a Forward Error Correction (FEC) process with a Reed-Solomon Code systematically abbreviated as in Figure 5 and an abbreviation rate of (100.94), i.e., of 100 symbols, 94 are information symbols and 6 are redundancy symbols, and a Cyclic Redundancy Check (CRC) process are used. This concept adds an additional delay of 80 ms to delays induced by the system.
Transparent transmission that makes no provision for error protection or error correction is needed in the case of ISDN services in which this additional delay is not permitted.
For DECT/ISDN intermediate systems as in ETSI Publication prETS
300xxx, Version 1.10, September 1996, Chapters 12.3 and 12.4, Annex A.2.1.1 and Annex B.2 this is the LU1 data service. The consequence of this is an unnecessarily high residual error rate on account of the redundancy of 160 bits (data transmission rate of 16 kb/s) that is available but unused.
It is the objective of the present invention to improve the transmission of user data in a hybrid telecommunications system, in particular an ISDN<-->DECT-specific RLL/WLL system.
Proceeding from the method defined in the preamble to Patent Claim 1, this objective has been achieved with the features set out in the description in Patent Claim 1.
The underlying concept of the present invention is that in a hybrid telecommunications system, in particular in an ISDN<-->DECT-specific RLL/WLL system, the user data is transmitted according to a user-data transmission protocol, wherein a data-transmission redundancy arising from the difference between a first data transmission capacity of an ISDN
system (640 bits of the ISDN B-channel) and a third data transmission capacity of a DECT/ISDN intermediate system (800 bits of the DECT double slot format)-- is used, at least in part, to avoid delays in transmission that occur in addition to the transmission delays generated by the system, compromising error-free user data transmission, while providing secured data transmission.
According to Claim 2, it is an advantage if the data transmission redundancy is used only in part. If this is done, the LU7 data service that is normally used for data transmission (if the additional transmission time of 80 ms can be accepted) can be used, with few modifications (e.g., leaving out the ARQ
and CRC data as in Figure 8) for the data transmission that is the basis of the present invention, in which the additional delay in unacceptable (key word: compatibility). Because of compatibility, the realisation costs are lower in hybrid tele-communications systems.
Other advantageous developments of the present invention are set out in the secondary claims.
One embodiment of the present invention is described on the basis of Figures 6 to 8.
Figures 6 to 8 show how the available redundancy is used to advantage with error-correcting codes in order to reduce the error rate that results from using the LU1 data service. In addition to the methods that use the total redundancy of 160 bits (data transmission rates of 16 kb/s) (the cross-hatched areas in Figures 6 and 7), Figure 8 shows a method whereby only a part of the redundancy is used (cross-hatched areas), whilst part remains unused (dotted area). In particular, Figure 6 shows the use of a folding code of rate 4/5.
Figure 7 shows the use of a systematically abbreviated Reed-Solomon Code with an abbreviation rate of (100,80) - i.e., of 100 symbols, 80 are information symbols and 20 are redundancy symbols.
Proceeding from Figure 5, Figure 8 shows the use of a systematically abbreviated Reed-Solomon Code with an abbreviation rate of (100,94) - i.e., of 100 symbols, 94 are information symbols and 6 are redundancy symbols; in contrast to the LU7 frame structure therein described, the control data for the ARQ
process and the data for the CRC process are not used. The advantage of the method shown in Figure 8 as compared to the method shown in Figures 6 and 7 is that the division of the 800 bits as in Figure 8 relative to the bit structure (not of the content that is to be transmitted with the bits!) comes closest to the bit division in the LU7 data service, and for this reason data transmission in the DECT/ISDN intermediate system and DECT/ISDN end systems is made simpler overall.
300444, April 1995).
Alternatively, the DIIS or the RW-TTS can be based in a Group Speciale Mobile or Global System for Mobile communication (GSM) systems see Information Spektrum 14 (1991), June, No. 3, Berlin, Germany; A.Mann: "Der GSM Standard - Grundlage fur digitale europaische Mobilfunknetze" [The GSM Standard - Basis for Digital European Mobile Radio Networks], pp. 137-152). In place of this, within the framework of a hybrid telecommun-ications system, it is also possible that the I-TTS be configured as a GSM system. Furthermore, other possibilities for realizing the DIIS or of the RW-TTS or the I-TTS are the above-discussed systems and future systems that are based on known multiple access methods such as frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA) hybrid multiple access methods formed from these.
The use of radio channels (e. g., DECT channels) in classical wire-based telecommunications systems like ISDN is becoming increasingly important, in particular as viewed against the background of future, alternative network operators who do not possess their own, complete wired-based networks.
Thus, for example, in the case of the RLL/WLL tele-communications sub-system, it is intended to make the RLL/WLL
connection technology available e.g., by tying-in the DECT system (DS) to the ISDN subscriber ISDN services on standard ISDN
buses(see Figure 1).
In the IDRW-TS shown in Figure 1, a telecommunications user (TC) and his terminal endpoint or terminal equipment (TE) are tied into the ISDN world, with the associated services available there, for example by way of a standardized S-bus, the DIIS (first telecommunications sub-system), which is preferably DECT-specific and incorporated in the RW-TSS, an additional, standardized S-bus of the (S-bus), network termination (NT), and a standardized U-bus of the I-TTS (second telecommuni-cations sub-system.
Essentially, the first telecommunications sub-system (DIIS) comprises two telecommunications buses, a DECT-intermediate fixed system (DIFS) telecommunications bus, and a DECT intermediate portable system (DIPS) second tele-communications bus that are connected to each other by way of a DECT air interface. Because of the DIFS quasi-fixed first telecommunications bus, the DIIS first telecommunications sub-s system forms the first local information transmission loop that has been defined above in this connection. The DIFS first telecommunications bus incorporates a radio fixed part (RFP), and inter-working unit IWU1 and interface circuitry INC1, for the S-bus. The second telecommunications bus DIPS incorporates a radio portable part (RPP) and an interworking unit IWU2, and interface circuitry INC2 for the S-bus. The radio fixed part (RFP) and the radio portable part (RPP) form the known DECT/GAP system (DGS).
Based on Nachrictentechnik Elektronik 42 (1992) Jan/Feb No. 1, Berlin, Germany: U.Pilger, "Struktur des DECT Standards"
[Structure of the DECT Standard], pp. 23-29, in conjunction with ETS 300 175-1 " ,9, October 1992, Figure 2 shows the TDMA
structure of a DECT/GAP system. Relative to the multiple-access method, the DECT/GAP system is a hybrid system in which, according to the TDMA principle as in Figure 2, it is possible to transmit radio messages in a predetermined time sequence from the radio fixed part RFP to the radio portable part RPP, and from the radio portable part RPP to the radio fixed part RFP (duplex operation) on ten frequencies in the frequency band between 1.88 and 1.90 Ghz. When this is done, the time sequence is determined by a multi-time frame MZR that occurs every 160 ms and which comprises 16 time frames ZR, each of which has a duration of 10 ms. Separated according to radio fixed part RFP and radio portable part RPP, information that applies to a C, M, N, P, or Q
channel as defined in the DECT standard is transmitted in these time frames ZR. If information for several of these channels is transmitted in one time frame ZR, then the transmission is effected according to a priority schedule, with M>C>N, and P>N.
Each of the 16 time frames ZR of the multi-time frame MZR is further divided into 24 time slots ZS, each of which is of a duration of 417 ~s; of these, 12 time slots ZS (time slots 0...11) are earmarked for transmission in the direction "radio fixed part RFP -> radio part RPP, and a further 12 time slots ZS
(time slots 12...23) are earmarked for transmission in the direction radio portable part RPP->radio fixed part RFP.
According to the DECT Standard, information that is 480 bits long is transmitted in each of these time slots ZS. Of these 480 bits, 32 bits are transmitted in a SYNC field as synchronizing information, and 388 bits are transmitted as user information in a D-field. The remaining 60 bits are transmitted in a Z-field, as additional information, and in a guard-time field, as security information. The 388 bits of the D-field that are transmitted as user information are further subdivided in a 64-bit long A-field, a 320-bit long B-field, and a 4-bit long X-CRC word. The 64-bit long A-field comprises an 8-bit long header, a 40-bit long data set with data for the C, Q, M, N, and F channels, and a 16-bit long A-CRC word. The DECT transmission structure shown in Figure 2 is designated as full-slot format. In addition, a double-slot format is also defined in the DECT Standard (see W093/21719).
Based on the OSI/ISO layered model (see the following):
(1): Information sheets - Deutsche Telekom, Year 48, 2/1995, pp.102-111;
(2): ETSI Publication ETS 300175-1...9, October 1992:
(3): ETSI Publication ETS 300102, February 1992;
(4): ETSI Publication ETS 300125, September 1991 (5) ETSI Publication ETS 300012, April 1992, Figure 3 shows a model of the C level of the IDRW-TS
(ISDN<-->DECT-specific RLL/WLL telecommunications system) that is shown in Figure 1 (see ETSI Publication prETS 300xxx, Version 1.10, September 1996, Chapter 5, Figure 3).
Based on the OSI/ISO layered model (see the following):
(1): Information sheets - Deutsche Telekom, Year 48, 2/1995, pp.102-111;
(2): ETSI Publication ETS 300175-1...9, October 1992;
(3): ETSI Publication ETS 300102, February 1992;
(4): ETSI Publication ETS 300125, September 1991;
(5) ETSI Publication ETS 300012, April 1992, Figure 4 shows a model of the U level, for speech data transmission, of the IDRW-TS (ISDN<-->DECT-specific RLL/WLL
telecommunications system} that is shown in Figure 1 (see ETSI
Publication prETS 300xxx, Version 1.10, September 1996, Chapter 5, Figure 4).
_g_ In the case of the DECT/ISDN intermediate system (DECT/ISDN Protocol Profile) as in Figure 1, it is possible, for example, to make an So connection available to an ISDN subscriber by wireless means by way of a DECT air interface. In this connection, depending on the ISDN-specific service (speech, data, etc.), in each instance a DECT radio channel is set up for the ISDN D-channel (data transmission rate 16 kb/s) and the two ISDN
B-channels (data transmission rate 64 kb/s). Initially, a DECT
traffic bearer in full-slot format, i.e., 320 bit user data per 10 ms or per TDMA frame; data transmission rates of 32 kb/s) is set up for the ISDN D-channel. If ISDN B-channels are required for the ISDN connection, then a DECT traffic bearer in full-slot format (i.e., 320 bits user data per 10 ms or per TDMA frame;
data transmission rages of 32 kb/s) or a DECT traffic bearer in double-slot format (800 bits user date per 10 ms or per TDMA
frame; data transmission rates of 80 kb/s) will be set up for each B-channel, depending on whether speech data or video data is to be transmitted. However, the full-slot format of the ISDN D-channel will only be needed for those times when a very large amount of ISDN signalling data is to be transmitted. Typically, this happens at the start of a connection. From these ISDN
signalling data, one can determine whether or not the ISDN
connection requires ISDN B-channels, and if so, how many.
Accordingly, one or two DECT traffic bearers are set up in double-slot format, or one or two double slots are seized. If the data rate on the ISDN D-channel now falls, the DECT traffic bearer in the full-slot format is dropped and signalling is continued in the A-field of one of the two DECT traffic bearers, in double-slot format. Unfortunately, this is not possible from the start, since the data rate of the ISDN D-channel is higher than that in the A-field of a DECT traffic bearer. For this reason, in the event that it is seen that the data rate in the ISDN D-channel is increasing again, the DECT traffic bearer in the full-slot format is also set up once again for the ISDN D-channel, as required. Using this mechanism, it is intended that the load on the DECT spectrum be minimized by the ISDN D-channel (see German Patent Application 19625142.7). However, if such an ISDN connection is first set up by way of the DECT air interface, each of the ISDN B-channels occupies a DECT double slot (accordingly, 2 of 120 DECT channels), until such time as the connection is dropped once again.
For the transmission of ISDN B-channel data at a data transmission rate of 64 kb/s, for DECT/ISDN intermediate systems as in ETSI Publication prETS 300xxx, Version I.10, September 1996, Chapters 12.3 and 12.4, Annex A.2.1.1 and Annex B.2, and for DECT/ISDN end systems as in ETSI Publication prETS 300434-1, January 1996, Annex B of the Lu7 data service, provision is made such that a combination of an Automatic Repeat Request (ARQ) process, a Forward Error Correction (FEC) process with a Reed-Solomon Code systematically abbreviated as in Figure 5 and an abbreviation rate of (100.94), i.e., of 100 symbols, 94 are information symbols and 6 are redundancy symbols, and a Cyclic Redundancy Check (CRC) process are used. This concept adds an additional delay of 80 ms to delays induced by the system.
Transparent transmission that makes no provision for error protection or error correction is needed in the case of ISDN services in which this additional delay is not permitted.
For DECT/ISDN intermediate systems as in ETSI Publication prETS
300xxx, Version 1.10, September 1996, Chapters 12.3 and 12.4, Annex A.2.1.1 and Annex B.2 this is the LU1 data service. The consequence of this is an unnecessarily high residual error rate on account of the redundancy of 160 bits (data transmission rate of 16 kb/s) that is available but unused.
It is the objective of the present invention to improve the transmission of user data in a hybrid telecommunications system, in particular an ISDN<-->DECT-specific RLL/WLL system.
Proceeding from the method defined in the preamble to Patent Claim 1, this objective has been achieved with the features set out in the description in Patent Claim 1.
The underlying concept of the present invention is that in a hybrid telecommunications system, in particular in an ISDN<-->DECT-specific RLL/WLL system, the user data is transmitted according to a user-data transmission protocol, wherein a data-transmission redundancy arising from the difference between a first data transmission capacity of an ISDN
system (640 bits of the ISDN B-channel) and a third data transmission capacity of a DECT/ISDN intermediate system (800 bits of the DECT double slot format)-- is used, at least in part, to avoid delays in transmission that occur in addition to the transmission delays generated by the system, compromising error-free user data transmission, while providing secured data transmission.
According to Claim 2, it is an advantage if the data transmission redundancy is used only in part. If this is done, the LU7 data service that is normally used for data transmission (if the additional transmission time of 80 ms can be accepted) can be used, with few modifications (e.g., leaving out the ARQ
and CRC data as in Figure 8) for the data transmission that is the basis of the present invention, in which the additional delay in unacceptable (key word: compatibility). Because of compatibility, the realisation costs are lower in hybrid tele-communications systems.
Other advantageous developments of the present invention are set out in the secondary claims.
One embodiment of the present invention is described on the basis of Figures 6 to 8.
Figures 6 to 8 show how the available redundancy is used to advantage with error-correcting codes in order to reduce the error rate that results from using the LU1 data service. In addition to the methods that use the total redundancy of 160 bits (data transmission rates of 16 kb/s) (the cross-hatched areas in Figures 6 and 7), Figure 8 shows a method whereby only a part of the redundancy is used (cross-hatched areas), whilst part remains unused (dotted area). In particular, Figure 6 shows the use of a folding code of rate 4/5.
Figure 7 shows the use of a systematically abbreviated Reed-Solomon Code with an abbreviation rate of (100,80) - i.e., of 100 symbols, 80 are information symbols and 20 are redundancy symbols.
Proceeding from Figure 5, Figure 8 shows the use of a systematically abbreviated Reed-Solomon Code with an abbreviation rate of (100,94) - i.e., of 100 symbols, 94 are information symbols and 6 are redundancy symbols; in contrast to the LU7 frame structure therein described, the control data for the ARQ
process and the data for the CRC process are not used. The advantage of the method shown in Figure 8 as compared to the method shown in Figures 6 and 7 is that the division of the 800 bits as in Figure 8 relative to the bit structure (not of the content that is to be transmitted with the bits!) comes closest to the bit division in the LU7 data service, and for this reason data transmission in the DECT/ISDN intermediate system and DECT/ISDN end systems is made simpler overall.
Claims (12)
1. A method for the transmission of user data in a hybrid telecommmunication system, especially an "ISDN<-->DECT
specific RLL/WLL system,"
a) wherein for the transmission of user data, the hybrid telecommunications system incorporates a1) a first telecommunications sub-system (I-TTS) with at least one first telecommunications channel with, in each instance, a first user data transmission capacity, and a2) a second telecommunications sub system (DIIS, RW-TTS) with a preset number of second telecommunications channels with, in each instance, a second user data transmission capacity, b) wherein in order to transmit the data, the second telecommunications subsystem (DIIS, RW-TTS) has a first telecommunications bus (DIFS) and a second telecommunications bus (DIPS), these being connected to each other by way of the second telecommunications channel or the second telecommunications channel, c) wherein the second telecommunications sub-system (DIIS, RW-TTS) is tied into the first telecommunications sub-system (I-TTS) as a local information transmission loop by way of the two telecommunication buses (DIFS, DIPS), d) wherein the first user data transmission capacity is smaller that a third user data transmission capacity that results from the preset number of the second tele-communications channels that each have the second data transmission capacity, characterized in that the user data is transmitted according to a user-data transmission protocol, whereby a data transmission redundancy arising from the difference between a first user data transmission capacity is used, at least in part, to avoid delays in transmission occuring in addition to system induced transmission delays compromising the error-free transmission of data, while providing fully secured data transmission.
specific RLL/WLL system,"
a) wherein for the transmission of user data, the hybrid telecommunications system incorporates a1) a first telecommunications sub-system (I-TTS) with at least one first telecommunications channel with, in each instance, a first user data transmission capacity, and a2) a second telecommunications sub system (DIIS, RW-TTS) with a preset number of second telecommunications channels with, in each instance, a second user data transmission capacity, b) wherein in order to transmit the data, the second telecommunications subsystem (DIIS, RW-TTS) has a first telecommunications bus (DIFS) and a second telecommunications bus (DIPS), these being connected to each other by way of the second telecommunications channel or the second telecommunications channel, c) wherein the second telecommunications sub-system (DIIS, RW-TTS) is tied into the first telecommunications sub-system (I-TTS) as a local information transmission loop by way of the two telecommunication buses (DIFS, DIPS), d) wherein the first user data transmission capacity is smaller that a third user data transmission capacity that results from the preset number of the second tele-communications channels that each have the second data transmission capacity, characterized in that the user data is transmitted according to a user-data transmission protocol, whereby a data transmission redundancy arising from the difference between a first user data transmission capacity is used, at least in part, to avoid delays in transmission occuring in addition to system induced transmission delays compromising the error-free transmission of data, while providing fully secured data transmission.
2. A method as defined in Claim 1, characterized in that the data transmission redundancy is used in part.
3. A method as defined in Claim 1 or Claim 2, characterized in that the first telecommunications sub-system (I-TTS) is an ISDN system and the first telecommunications channel or the first telecommunications channels are an ISDN B-channel or ISDN B-channels; and in that the first user-data trans-mission capacity matches the capacity of an ISDN B-channel.
4. A method as defined in one of the Claims 1 to 3, characterized in that the second telecommunications sub-system (DIIS, RW-TTS) is based on a DECT system and the preset number of second telecommunications channels are DECT channels; and in that the second user data transmission capacity matches the capacity of a DECT full slot channel and the second user data transmission capacity matches the capacity of a DECT double-slot channel.
5. A method as defined in one of the Claims 1 to 3, characterized in that the second telecommunications sub-system (DIIS, RW-TTS) is based on a GSM system and the preset number of second telecommunications channels are GSM channels.
6. A method as defined in one of the Claims 1 to 3, characterized in that the second telecommunications sub-system (DIIS, RW-TTS) is based on a PHS system, a WACS system, or a PACS
system and the preset number of second telecommunications channels are PHS, WACS, or PACS channels.
system and the preset number of second telecommunications channels are PHS, WACS, or PACS channels.
7. A method as defined in one of the Claims 1 to 3, characterized in that in that the second telecommunications sub-system (DIIS, RW-TTS) is based on an IS-54 or a PDS system, and the preset number of second telecommunications channels are IS-54 channels or PDC channels.
8. A method as defined in one of the Claims 1 to 3, characterized in that the second telecommunications sub-system (DIIS, RW-TTS) is based on a CDMA system,a TDMA system, a FDMA
system or a system that--relative to these transmission standards--is a hybrid system and the preset number of second telecommunications channels are CDMA, TDMA, or FDMA channels, ro channels that--relative to these transmission standards--are hybrid channels.
system or a system that--relative to these transmission standards--is a hybrid system and the preset number of second telecommunications channels are CDMA, TDMA, or FDMA channels, ro channels that--relative to these transmission standards--are hybrid channels.
9. A method as defined in Claim 4, characterized in that the first telecommunications bus (DIFS) is a DECT Intermediate Fixed System (DIFS) and the second telecommunications bus is a DECT Intermediate Portable System (DIPS).
10. A method as defined in one of the Claims 1 to 9, characterized in that the user data transmission protocol is the LU1 data service augmented by the Reed-Solomon Code.
11. A method as defined in Claim 10, characterized in that the Reed-Solomon code is the systematically abbreviated Reed-Solomon Cone of the LU7 data service.
12. A method as defined in one of the Claims 1 to 9, characterized in that the user data transmission protocol is the LU1 data service augmented by the "4/5" folding rate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19643776A DE19643776C1 (en) | 1996-10-23 | 1996-10-23 | Method for transmitting user data in a hybrid telecommunications system, in particular an "ISDN DECT-specific RLL / WLL" system |
| DE19643776.8 | 1996-10-23 | ||
| PCT/DE1997/002324 WO1998018285A1 (en) | 1996-10-23 | 1997-10-10 | Method for the transmission of user data in a hybrid telecommunication system especially an 'isdn ←→ dect specific rll/wll' system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2269526A1 true CA2269526A1 (en) | 1998-04-30 |
Family
ID=7809582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002269526A Abandoned CA2269526A1 (en) | 1996-10-23 | 1997-10-10 | Method for the transmission of user data in a hybrid telecommunication system especially an "isdn ?? dect specific rll/wll" system |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0934675B1 (en) |
| JP (1) | JP3301025B2 (en) |
| CN (1) | CN1225789A (en) |
| AR (1) | AR008499A1 (en) |
| AT (1) | ATE212776T1 (en) |
| AU (1) | AU5047398A (en) |
| BR (1) | BR9713273A (en) |
| CA (1) | CA2269526A1 (en) |
| DE (2) | DE19643776C1 (en) |
| ES (1) | ES2171916T3 (en) |
| PL (1) | PL330792A1 (en) |
| WO (1) | WO1998018285A1 (en) |
| ZA (1) | ZA979446B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19823683B4 (en) * | 1998-05-27 | 2004-05-06 | Siemens Ag | Method for transmitting information indicating the transmission capacity from a central to at least one decentralized device via a radio link |
| IL133505A0 (en) * | 1998-12-28 | 2001-04-30 | Eci Telecom Ltd | Multi-port, single-line subscriber terminal |
| WO2012079236A1 (en) * | 2010-12-16 | 2012-06-21 | 北京航空航天大学 | Transmission control method of video-stream based on dual time scale |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2243973A (en) * | 1990-05-12 | 1991-11-13 | Motorola Inc | Data network interface |
| EP0635185A1 (en) * | 1992-04-09 | 1995-01-25 | Siemens Aktiengesellschaft | Method of structuring a b-field format in a dect-standard system |
| DE19625142C2 (en) * | 1996-04-04 | 1998-10-29 | Siemens Ag | Method for assigning telecommunication channels of different channel capacity in a hybrid telecommunication system, in particular an "ISDN <--> DECT-specific RLL / WLL" system |
-
1996
- 1996-10-23 DE DE19643776A patent/DE19643776C1/en not_active Expired - Fee Related
-
1997
- 1997-10-10 CA CA002269526A patent/CA2269526A1/en not_active Abandoned
- 1997-10-10 DE DE59706263T patent/DE59706263D1/en not_active Expired - Lifetime
- 1997-10-10 BR BR9713273-0A patent/BR9713273A/en unknown
- 1997-10-10 JP JP51878998A patent/JP3301025B2/en not_active Expired - Fee Related
- 1997-10-10 AU AU50473/98A patent/AU5047398A/en not_active Abandoned
- 1997-10-10 WO PCT/DE1997/002324 patent/WO1998018285A1/en active IP Right Grant
- 1997-10-10 ES ES97913096T patent/ES2171916T3/en not_active Expired - Lifetime
- 1997-10-10 EP EP97913096A patent/EP0934675B1/en not_active Expired - Lifetime
- 1997-10-10 PL PL97330792A patent/PL330792A1/en unknown
- 1997-10-10 CN CN97196477A patent/CN1225789A/en active Pending
- 1997-10-10 AT AT97913096T patent/ATE212776T1/en not_active IP Right Cessation
- 1997-10-22 AR ARP970104884A patent/AR008499A1/en unknown
- 1997-10-22 ZA ZA9709446A patent/ZA979446B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ATE212776T1 (en) | 2002-02-15 |
| PL330792A1 (en) | 1999-06-07 |
| EP0934675B1 (en) | 2002-01-30 |
| ZA979446B (en) | 1998-04-23 |
| AU5047398A (en) | 1998-05-15 |
| JP2000509929A (en) | 2000-08-02 |
| AR008499A1 (en) | 2000-01-19 |
| ES2171916T3 (en) | 2002-09-16 |
| CN1225789A (en) | 1999-08-11 |
| DE59706263D1 (en) | 2002-03-14 |
| WO1998018285A1 (en) | 1998-04-30 |
| JP3301025B2 (en) | 2002-07-15 |
| DE19643776C1 (en) | 1998-08-27 |
| EP0934675A1 (en) | 1999-08-11 |
| BR9713273A (en) | 2000-03-28 |
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| EEER | Examination request | ||
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| FZDE | Discontinued |
Effective date: 20031010 |