HK1021684A - Method for the transmission of user data in a hybrid telecommunication system especially and "isdn←→dect specific rll/wll" system - Google Patents

Description

Method for transmitting application data in a hybrid telecommunication system, in particular in an RLL/WLL system dedicated to ISDN  DECT

no marking

In communication systems having communication transmission lines between a communication source and a communication sink, transmitting and receiving devices are used for communication processing and communication transmission, and are provided with a plurality of receiving devices.

1) The communication processing and communication transmission can take place in one preferred transmission direction (simplex operation) or in both transmission directions (duplex operation),

2) the communication information processing is either analog or digital,

3) the transmission of communication information via the remote transmission line IS wired or based on various different communication information transmission methods FDMA (frequency division multiple access), TDMA (time division multiple access) and/or CDMA (code division multiple access) -e.g. according to wireless standards like DECT, GSM, WACS or PACS, IS-54 (international standard 54), PHS, PDC, etc. [ please see IEEE (institute of electrical and electronics engineers) journal of communication, 1 month 1995, pages 50-57; falcon et al: "time division multiple access method for wireless personal communication" ].

"communication information" is a comprehensive concept that represents both meaning (information) and physical expression (signal). Various signal forms may occur despite the same meaning of a communication, that is, the same information. Thus, for example, a communication relating to an object can

(1) In the form of an image, the image is,

(2) as a statement of what is said,

(3) as a statement to be written to,

(4) transmitted as coded sentences or images. The transmission according to (1) … (3) is usually characterized by a continuous (analog) signal, whereas discontinuous signals (e.g. pulses, digital signals) are usually generated in the transmission according to (4).

Based on this general definition of a communication information system, the invention relates to a method and a telecommunication interface for transmitting continuous and/or discontinuous data streams in a hybrid telecommunication system, in particular in an RLL/WLL system specific for ISDN  DECT according to the preamble of claim 1.

The various hybrid telecommunication systems are, for example, communication systems comprising various wireless and/or wireline telecommunication systems.

On behalf of a number of hybrid telecommunication systems, from these documents "communications technology electronics, berlin 45(1995) stages 1, 21 to 23 and 3, 29 and 30", and IEE forum 1993,173; (1993) pages 29/1-29/7; hind, f.halsall: "cordless access to ISDN basic rate services", based on a DECT/ISDN intermediate system DIIS according to ETSI (european telecommunications standards institute) publication pr ETS300XXX, release 1.10,1996, 9 months, fig. 1 shows a communication system with an ISDN telecommunications local system I-TTS [ please refer to the document "electronics of communication technology, berlin 41-43, part: 1 to 10, T1 (1991) No. 3, pages 99 to 102; t2 (1991) No. 4, pages 138 to 143; t3 (1991) at stages 5, 179 to 182 and 6, 219 to 220; t4 (1991) No. 6, pages 220 to 222 and (1992) No. 1, pages 19 to 20; t5 (1992) No. 2, pages 59 to 62 and (1992) No. 3, pages 99 to 102; t6 (1992) stage 4, pages 150 to 153; t7 (1992) No. 6, pages 238 to 241; t8 (1993) No. 1, pages 29 to 33; t9 (1993) stage 2; pages 95 to 97 and (1993) phase 3, pages 129 to 135; t10 (1993) No. 4, pages 187 to 190; ") and a DECT-specific RLL/WLL telecommunication local system RW-TTS, an ISDN  DECT-specific RLL/WLL telecommunication system TDRW-TS (integrated services digital network)  wireless local loop/wireless local loop).

The DECT/ISDN intermediate system DIIS or the RLL/WLL telecommunications local system RW-TTS is here based in particular on a DECT/GAP system DGS [ digital enhanced (formerly: European) cordless telecommunications ]; please refer to (1): communication electrons 42(1992) month 1/month 2, stage 1, Berlin, DE; pilger "structure of DECT standard", pages 23 to 29 in association with ETSI publication ETS300175-1 … 9,1992, 10 months; (2): telecommunication report 16(1993), No. 1, j.h.koch: the digital equipment modernization for cordless telecommunications-the DECT standard opens up a new field of application ", pages 26 to 27; (3) tec2/93-Ascom journal of technology "various routes to universal mobile telecommunications", pages 35 to 42; (4) philips telecommunications review, volume 49, No. 3, month 9 1991, r.j.mulder: "DECT, a universal cordless access system"; (5) WO93/21719 (FIGS. 1 to 3 and the description thereof). The GAP standard (generic access profile) is a subordinate part of the DECT standard, which assumes the task of guaranteeing interoperability of the DECT air interface for telephony purposes (see ETSI publication pretsz 300444, month 4 1995).

The DECT/ISDN intermediate system DIIS or the RLL/WLL telecommunications local system RW-TTS can alternatively also be based on the GSM system (private group for mobile communications or global system for mobile communications; please refer to the field of informatics, 14(1991), 6 th month, 3 rd, Berlin, DE; A.Mann: "GSM Standard-Foundation for European digital Mobile radio networks", pages 137 to 152). Alternatively, the ISDN telecommunication local system I-TTS can also be designed as a GSM system in the context of a hybrid telecommunication system.

In addition, the systems mentioned at the outset and future systems based on the known multiple access methods FDMA (frequency division multiple access), TDMA (time division multiple access), CDMA (code division multiple access) and the hybrid multiple access methods formed therefrom can be considered as further possibilities for implementing DECT/ISDN intermediate systems DIIS or RLL/WLL telecommunication local systems RW/TTS or ISDN telecommunication local systems.

The adoption of radio channels, such as DECT channels, as in ISDN, is gaining increasing importance in conventional wired telecommunication systems, especially in the context of network operators who may choose in the future without their own complete wired network.

Thus, for example, in the case of the RLL/WLL telecommunication local systems RW-TTS for the radio connection technology RLL/WLL (radio local loop/radio local loop), for example, in the case of the incorporation of DECT systems DS, the various ISDN services on the standard ISDN interfaces are to be made available to the ISDN subscribers (see fig. 1).

In the RLL/WLL telecommunication system ISRW-TS according to fig. 1, which is specific to ISDN  DECT, for example via a standardized S interface (S-BUS), via a standardized U interface which is formed as a local communication information transmission loop, in particular as specific to DECT and is included in the RLL/WLL telecommunication local system RW-TTS, the DECT/ISDN intermediate system DIIS (first telecommunication local system), via a further standardized S interface (S-BUS), a network terminal NT and an ISDN telecommunication local system I-TTS (second telecommunication local system). The TCU of a telecommunications subscriber (user) with its terminal equipment TE is brought into the ISDN field with the services available therein.

The first telecommunications local system DIIS is essentially composed of two telecommunications interfaces, a first telecommunications interface DIFS (DECT intermediate fixed system) and a second telecommunications interface DIPS (DECT intermediate portable system), which are connected to one another wirelessly, for example via a DECT air interface. The first telecommunications local system DIIS forms, owing to the quasi-stationary first telecommunications interface DIFS, the local communication information transmission loop previously defined in this connection. The first telecommunications interface DIFS contains a radio fixed part RFP, an adaptation unit IWUI () and an interface circuit INC1 leading to the S interface. The second telecommunications interface DIPS comprises a wireless mobile part RPP and an adaptation unit IWU2 (interworking unit) and an interface circuit INC2 to the S-interface. The radio fixed part RFP and the radio mobile part RPP form here the known DECT/GAP system DGS.

According to the literature "communications technology electronics 42(1992) 1/2 month, 1 st, Berlin, DE; pilger: "structure of DECT standard", pages 23 to 29, combined with ETS300175-1, 10 months 1 … 9,1992 ", fig. 2 shows the TDMA structure of the DECT/GAP system. The DECT/GAP system is a hybrid system for various multiple access methods, on which wireless communication information can be transmitted from the base station RFP to the mobile part RPP and from the mobile part RFF to the base station RFP (duplex operation) in a prescribed time sequence in accordance with the TDMA principle of fig. 2 on ten frequencies in a frequency band between 1.88 and 1.90GHz in accordance with the FDMA principle. The time sequence is determined by a multiple time frame MZR, which occurs every 160ms and which has 16 time frames ZR with a duration of 10ms each. In this time frame ZR, information relating to a C, M, N, P, Q channel defined in the DECT standard is transmitted separately from the base station RFP and the mobile part RPP. If information of several of these channels is transmitted in a time frame ZR, the transmission is carried out according to a priority list with M > C > N and P > N. Each of the 16 time frames ER of the multiple time frames MZR is subdivided into 24 time slots ZS with a duration of 417 μ s each, of which 12 time slots ZS (time slot 0 … 11) are determined for the transmission direction "base station RFP → mobile part RPP", and the other 12 time slots ZS (time slot 12 … 23) are determined for the transmission direction "mobile part RPP → base station RFP". In each of these time slots ZS, information with a bit length of 480 bits is transmitted in accordance with the DECT standard. From these 480 bits, 32 bits are transmitted as synchronization information in a SYNC field, and 388 bits are transmitted as useful information in a D field. The remaining 60 bits are transmitted as overhead information in a Z field and as guard information in a "guard time" field. The 388 bits of the D field, which are useful information transfers, are subdivided into 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 consists of an 8-bit long header, a 40-bit long data block with C, Q, M, N, P etc. channel data and a 16-bit long "A-CRC" word. The DECT transmission structure represented in fig. 2 is referred to as "full slot format". Additionally, a "dual time slot format" is specified in the DECT standard (see WO 93/21719).

Based on the OSI/ISO layer model [ please refer to (1): lecture-german telecommunications, year roll 48, pages 2/1995,102 to 111; (2) ETSI publication ETS300175-1 … 9,1992, 10 months; (3) ETSI publication ETS300102,1992 month 2; (4) ETSI publication ETS300125,1991 month 9; (5) ETSI publication ETS300012,1992 month 4, figure 3 shows a model of the C-plane according to figure 1 "ISDN  DECT specific RLL/WLL telecommunication system IDRW-TS (please refer to ETSI publication PRETS300XXX, release 1.10,1996 month 9, chapter 5, figure 3).

Based on the OSI/ISO layer model [ please refer to (1): lecture-german telecommunications, year roll 48, pages 2/1995,102 to 111; (2) ETSI publication ETS300175-1 … 9,1992, 10 months; (3) ETSI publication ETS300102,1992 month 2; (4) ETSI publication ETS300125,1991, 9 months; (5) ETSI publication ETS300012,1992 month 4, FIG. 4 shows a model of the U-plane for speech data transmission according to IDRW-TS of the "ISDN  DECT proprietary RLL/WLL telecommunication system of FIG. 1 (please refer to ETSI publication pr ETS300XXX, version 1.10,1996 month 9, chapter 5, FIG. 4).

In the DECT/ISDN intermediate system (DECT/ISDN protocol profile) according to fig. 1, for example, an S can be connected wirelessly via a DECT air interface. The terminal is intended for one ISDN subscriber. Depending on the ISDN-specific services (voice, data, etc.), a DECT radio channel for an ISDN-D channel (data transmission rate of 16kb/s) and two ISDN-B channels (data transmission rate of 64kb/s) are each established. For this ISDN-D channel, a DECT communication bearer in "full slot format" is first established, meaning that 320 bits of application data per 10ms or per TDMA frame; the data transmission rate is 32 kb/s). If ISDN-B channels are required for this ISDN connection, a DECT communications bearer in "full time slot format" is set up, i.e. data is applied every 10ms or 320 bits per TDMA frame, depending on whether, for example, voice data or image data is to be transmitted; 32kb/s) or to establish a DECT communication bearer in "dual slot format" (800 bits of application data per 10ms or per TDMA frame; data transmission rate of 80 kb/s). The "full time period format" of the ISDN-D channel is however only required for the time when much ISDN signaling data has to be transmitted. This typically occurs at the beginning of the connection. From this ISDN-D channel signalling it becomes clear whether and how many ISDN-B channels are required for the ISDN connection. Accordingly, one or two DECT communication bearers in "dual slot format" are set up, or one or two "dual slots" are occupied. If the data rate on the ISDN-D channel now drops, the DECT communication bearer in "dual slot format" is interrupted and the signaling is continued in the a field of one of the two DECT communication bearers in "dual slot format". This is unfortunately not possible from the beginning because the data rate of the ISDN-D channel is higher than in the a field of the DECT communication bearer. Thus, when a data rate re-growth in the ISDN-D channel is found, the DECT communications bearer in "full time slot format" is re-established for this ISDN-D channel, if necessary. The burden in the DECT field via this ISDN-D channel should be reduced by this mechanism (see german patent application 19625142.7). If, however, a such ISDN connection is first established via the DECT air interface, each of these ISDN-B channels takes up a "DECT double period" (corresponding to 2 of the 120 DECT channels), i.e. until the connection is interrupted again.

For ISDN-B channel data transmission with a data transmission rate of 64kb/s, LU7 data traffic is arranged for DECT/ISDN intermediate systems according to ETSI publication pr ETS300XXX, release 1.10,1996, 9 months, chapters 12.3 and 12.4, annex a.2.1.1 and annex b.2, and for DECT/ISDN end systems according to ETSI publication pr ETS300434-1,1996, 1 month, annex B, which data traffic uses a combination of a "forward error correction" (FEC) method and a "cyclic redundancy check" (CRC) method originating from an "automatic repeat request" method (ARQ) with systematically shortened reed-solomon codes according to fig. 5 and a shortening rate of (100,94) -meaning 94 information symbols and 6 signal redundancies out of 100 symbols. This concept causes an additional delay of about 80ms for various delays that have been decided by the system.

On ISDN services to be transmitted, this extra delay is not allowed on these ISDN services, and a transparent transmission without error protection or error correction is necessary. This is the LU 1-data service for each DECT/ISDN intermediate system as per ETSI publication pr ETS300XXX, release 1.10,1996, 9 th day, chapters 12.3 and 12.4, annex a.2.1.1 and annex b.2. The consequence of this is an unnecessarily high residual error rate due to the dominant, but unused, 160-bit redundancy (16kb/s data transmission rate).

The aim of the invention is to improve the transmission of application data in a hybrid telecommunication system, in particular in an ISDN  DECT-specific RLL/WLL system.

This object is achieved by the features specified in the characterizing part of claim 1, based on the method specified in the preamble of claim 1.

The invention relates to a method for transmitting application data in a hybrid telecommunication system, in particular in an RLL/WLL system specific to ISDN  DECT, according to an application data transmission protocol, in which data transmission redundancies generated by the difference between a first application data transmission capacity of the ISDN system (640 bits of the ISDN-B channel) and a third application data transmission capacity of the DECT/ISDN intermediate system (800 bits of the DECT double slot format) are generated locally for avoiding transmission delays which are added to the transmission delays determined by the system, at the expense of error-free transmission of the application data, while the application data of the application data are completely guaranteed.

This is advantageous if this data transmission redundancy is used only locally, as claimed in claim 2. The LU7 data traffic normally used for data transmission (if an additional transmission duration of 80ms is tolerable or acceptable) can thus also be used for data transmission according to the invention with a small amount of change (for example, removal of ARQ data and CRC data according to fig. 8), in which case this additional delay is not acceptable (control means: compatibility). The implementation costs in the hybrid telecommunication system are also low due to this compatibility.

Further advantageous developments of the invention are specified in the remaining dependent claims.

An embodiment of the present invention is described with reference to fig. 6 to 8.

Fig. 6 to 8 show how the dominant redundancy with error correction codes is used to reduce the error rate that occurs when LU1 data traffic is used, respectively. In addition to these methods (shaded surfaces in fig. 6 and 7) which utilize redundancy of an overall 160 bits (data transfer rate of 16kb/s), fig. 8 shows a method on which only a portion of the redundancy is utilized (shaded surface), while a portion remains unutilized (dotted surface). In detail:

fig. 6 shows the use of a folding code for rate 4/5.

Fig. 7 shows the use of systematically shortened reed-solomon codes with a shortening rate of (100,80) -meaning that 100 symbols are 80 information symbols and 20 symbols are redundant.

Fig. 8 shows, on the basis of fig. 5, the use of a systematically shortened reed solomon code with a shortening rate of (100,94), i.e. 94 information symbols and 6 symbol redundancies out of 100 symbols, in which the control data of the ARQ method and the data of the CRC method are not utilized in relation to the LU7 frame structure described there. The advantage of the method according to fig. 8 over the various methods according to fig. 6 and 7 is that the division of 800 bits according to fig. 8 is closest to the division of bits in the LU7 data service from the point of view of the bit structure (not from the point of view of the content to be transmitted using bits) and thus the data transmission in these DECT/ISDN intermediate systems and DECT/ISDN end systems is simplified overall.

Claims (12)

1. A method for transmitting application data in a hybrid telecommunication system, especially in an ISDN  DECT specific RLL/WLL system,

a) the hybrid telecommunication system for application data transmission comprises

a1) A first telecommunications local system (I-TTS) with at least one first telecommunications channel each having a first application data transmission capacity, and

a2) a second telecommunications local system (DIIS, RW-TTS) with a defined number of second telecommunications channels, which each have a second application data transmission capacity,

b) the second telecommunication local system (DIIS, RW-TTS) for transmitting data has a first telecommunication interface (DIFS) and a second telecommunication interface (DIPS), which are connected to one another via the second telecommunication channel or channels,

c) the second telecommunication local system (DIIS, RW-TTS) as a local communication channel transmission loop is incorporated into the first telecommunication local system (I-TTS) via the two telecommunication interfaces (DIFS, DIPS).

d) The first application data transmission capacity is smaller than a third application data transmission capacity, which is generated by the second telecommunication channels with the second application data transmission capacity for a predetermined number of days, characterized in that the application data is transmitted according to an application data transmission protocol, wherein a data transmission redundancy generated by the difference between the first application data transmission capacity and the third application data transmission capacity is used at least partially to avoid transmission delays caused by system-dependent transmission delays while completely ensuring the application data transmission of the application data.

2. A method according to claim 1, characterized in that data transmission redundancy is partly exploited.

3. A method according to claim 1 or 2, characterized in that the first telecommunications local system (I-TTS) is an ISDN system and the first telecommunications channel or channels is an ISDN-B channel or channels, and that the first application data transmission capacity corresponds to the capacity of an ISDN-B channel.

4. A method according to one of claims 1 to 3, characterized in that the second telecommunication local system (DIIS, RW-TTS) is built on a DECT system, and the prescribed number of second telecommunication channels are DECT channels, and the second application data transmission capacity corresponds to the capacity of a "DECT full time" channel, and the second application data transmission capacity corresponds to the capacity of a "DECT double time" channel.

5. A method according to one of claims 1 to 3, characterized in that the second telecommunication local system (DIIS, RW-TTS) is established on a GSM system and the defined number of second telecommunication channels are GSM channels.

6. A method according to one of claims 1 to 3, characterized in that the second telecommunication local system (DIIS, RW-TTS) is set up on a PHS system, a WACS system or a PACS system, and that the defined number of second telecommunication channels are PHS channels, WACS channels or PACS channels.

7. A method according to one of claims 1 to 3, characterized in that the second telecommunication local system (DIIS, RW-TTS) IS built on an "IS-54" system or a PDC system and the defined number of second telecommunication channels are "IS-54" channels or PDC channels.

8. A method according to one of claims 1 to 3, characterized in that the second telecommunication local system (DIIS, RW-TTS) is built on a CDMA system, a TDMA system, an FDMA system or a system which is mixed in respect of the said transmission standards, and that the prescribed number of second telecommunication channels are CDMA channels, TDMA channels, FDMA channels or channels which are mixed in respect of the said transmission standards.

9. A method according to claim 4, characterized in that the first telecommunication interface (DIFS) is a DECT Intermediate Fixed System (DIFS) and the second telecommunication interface (DIPS) is a DECT Intermediate Portable System (DIPS).

10. Method according to one of the claims 1 to 9, characterized in that the application data transmission protocol is LU1 data traffic with an extended reed-solomon code.

11. A method according to claim 10, characterized in that the reed-solomon code is a systematically shortened reed-solomon code of the LU7 data traffic.

12. Method according to one of the claims 1 to 9, characterized in that the application data transfer protocol is an LU1 data service extended with a folding code of "4/5" folding rate.