Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W92/00—Interfaces specially adapted for wireless communication networks
  • H04W92/04—Interfaces between hierarchically different network devices
  • H04W92/12—Interfaces between hierarchically different network devices between access points and access point controllers
• • 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
  • H04Q11/0478—Provisions for broadband connections
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/54—Store-and-forward switching systems 
  • H04L12/56—Packet switching systems
  • H04L12/5601—Transfer mode dependent, e.g. ATM
  • H04L2012/5603—Access techniques
  • H04L2012/5604—Medium of transmission, e.g. fibre, cable, radio
  • H04L2012/5607—Radio
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/54—Store-and-forward switching systems 
  • H04L12/56—Packet switching systems
  • H04L12/5601—Transfer mode dependent, e.g. ATM
  • H04L2012/5638—Services, e.g. multimedia, GOS, QOS
  • H04L2012/5646—Cell characteristics, e.g. loss, delay, jitter, sequence integrity
  • H04L2012/5652—Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
  • H04L2012/5653—Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly using the ATM adaptation layer [AAL]
  • H04L2012/5654—Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly using the ATM adaptation layer [AAL] using the AAL1
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/54—Store-and-forward switching systems 
  • H04L12/56—Packet switching systems
  • H04L12/5601—Transfer mode dependent, e.g. ATM
  • H04L2012/5638—Services, e.g. multimedia, GOS, QOS
  • H04L2012/5671—Support of voice

Definitions

• the invention relates to a method and a device for data transmission in mobile radio systems between a base station controller and associated base station transceivers.
• Mobile radio systems like other communication systems, are hierarchical.
• the top hierarchical level comprises a mobile switching center MSC, which on the one hand establishes the connection to other networks and on the other hand is connected to a large number of decentralized base station controllers BSC.
• a base station controller BSC represents the next lower hierarchy level of the mobile radio network and in turn supplies a large number of assigned base transceiver stations BTS for a limited territory.
• a base transceiver station BTS in turn represents the next lower hierarchy level and serves a variety of mobile stations such as a cell phone.
• the connection between the BSC and the BTS is wired or via radio.
• the interface is physically a PCM30 (pulse code modulation with 30 channels, each with a transmission rate of 64kBit / s), whereby an Abis protocol is used.
• the BTS contains a BCF (Base Controller Function) and several TRX (Transceivers).
• the BCF is used for the internal control of the BTS.
• the TRX implement an air interface (Air Interface Um 6) with 8 user channels per TRX.
• the user channels are designed for the transmission of compressed speech with a data rate of 13 kbps and can be occupied by mobile stations for the purpose of communication.
• the BSC and BTS have to be transmitted bidirectionally via the interface: 8 user channels per TRX 1 signaling channel per TRX 1 signaling channel per BTS to the BCF.
• the worst case in terms of transmission technology arises when the speech vocoders that convert the language from 13 kbps to the standard value of 64 kbps and vice versa are in the BTS and no further grooming variants are used.
• each of the named channels occupies a full 64 kbps timeslot in the PCM30, ie a BTS with 1 TRX occupies 10 timeslots, a BTS with 2 TRX occupies 19 timeslots etc. It has therefore been adopted that the speech vocoder in BSC are arranged so that the 8 useful channels of a TRX, each filled from 13 kbps to 16 kbps, after corresponding multiplexing as subslots only 2 full 64 kbps
• Grooming means the improved arrangement of data, i.e. data not required, such as internal data
• Signaling data are eliminated and the required data is compressed in such a way that there are no gaps between the data. Due to the underutilization of the signaling channels, these can be individual or in complex
• the signaling channels for the TRX and the BTS are combined to form a common signaling channel with a total of only 64 kbps.
• the first TRX of a BTS only serves 6 user channels, the remaining 2 channels are used for specific signaling between BTS and the
• Mobile stations are required and their content does not have to go to the BSC are transmitted and are accordingly omitted in the transmission. If several sectors are served by a BTS as independent territories, this applies to the first TRX of each sector.
• the signaling channels compressed to 16 kbps are multiplexed into the gaps which have become free in accordance with the preceding point.
• PCM30 can also serve BTS that have a large number of TRX, which leads to a reduction in costs for the network infrastructure.
• These BTS serve only a low market value (small number of active mobile subscribers) and generate only low income.
• a PCM30 is still required as a leased line or microwave link, which, regardless of the low load, cause the full costs for these transmission links.
• the PCM30 is a point-to-point connection and a transmission link is required for each connection BSC to a BTS.
• the multiplexing of the signals of a plurality of BTSs into a PCM30, which is customary as prior art, and the connection of these BTSs to the BSC in a row structure also eliminates this
• the invention is therefore based on the technical problem of creating a method and device for data transmission in mobile radio systems by means of which an improved utilization of the transmission capacities is made possible
• ATM in the train system enables data connections with any data rates and without restriction to certain levels of the data rates to be transmitted together in one physical channel, as long as the sum of the data rates does not exceed the capacity of the physical channel.
• data links with a dynamically variable data rate are also or can be transmitted in burst mode without having to maintain the maximum rate for each of these connections. All of this allows the physical channels to be used optimally, so that the number of them corresponds to the existing ones
• Fig. 1 is a block diagram of a device for communication in
• FIG. 2 shows a block diagram of a radio base station
• FIG. 3 shows a block diagram of a BTS access unit
• 4 shows a block diagram of a PCM30 interface module
• Fig. 5 data diagrams for the processing and transmission of user data
• Fig. 6 data diagrams for the processing and transmission of OAM data.
• the device 1 for communication in mobile radio systems comprises a BSC 2, a radio base station 3 and a plurality of BTS 4, each of which is assigned a BTS access unit 5.
• the radio base station 3 is connected to the BSC 2 via at least one PCM30 with Abis protocol, which is implemented in hardware by a PCM30 interface module 6.
• the radio base station 3 and the BSC 2 are preferably only a few meters apart, so that the physical connection can be realized by inexpensive twisted pair connections.
• the BTS 4 and the associated BTS access units 5 are also each connected to one another via a PCM30 interface module 7, this connection preferably also being established physically via a twisted pair connection.
• an interface variant corresponding to the ring circuit can be used, in which the signals of a plurality of BTS 4 are multiplexed into a PCM30 in order to minimize the number of PCM30s required in the radio base station 3 and the BSC 2, so that compatibility with the previous one used systems is given.
• the radio base station 3 converts the signals of the BSC 2 into an air interface 8 with point-to-multipoint characteristics, so that, in contrast to the prior art, no two-point connection of the BSC 2 is required to close the ring.
• the BTS access units 5 receive the data sent by the radio base station 3 and transfer them to the associated BTS 4 via the respective PCM30 interface module 7, the data corresponding to the same form as in the direct transmission from BSC 2 to the BTS 4 according to the state of the art.
• Each BTS 4 is only provided with as much transmission capacity as is currently required. For this purpose, the data transfer from the radio base station 3 to the BTS
• Access units 5 are preferably implemented using ATM (Asynchronous Transfer Mode).
• the ATM includes that the data is transmitted in packet-oriented form, so-called ATM cells, whereby by definition one cell has a constant length of 53 octets or bytes, 5 octets being used as headers and the remaining 48 octets as payloads.
• the header contains the information for identifying a virtual channel that has been assigned to a data connection.
• the data of many virtual channels can be transmitted asynchronously multiplexed in a physical channel and assigned to the respective data connection on the receiving side by means of the header of each ATM cell.
• Data rates and without restriction to certain levels of the data rates can be transmitted together in one physical channel as long as the sum of the data rates does not exceed the capacity of the physical channel. Further advantages are that data connections with a dynamically (stochastically) changeable data rate or with burst operation can also be transmitted without having to maintain the maximum rate for each of these connections. In the case of data connections of this type, the sum of their data rates may exceed the capacity of the physical channel if it can be accepted that data is lost or delayed during peak load. Data connections to which this applies can be marked accordingly in the header of the ATM cells, so that loss or delay are only used for this application.
• the radio base station 3 comprises one or more PCM30 interface modules 6 with one
• PCM30 port 9 PCM30 port 9
• network management controller 10 PCM30 port 9
• channel mapping module 12 PCM30 port 12
• the coupling with the BSC 2 of the mobile radio system takes place via the PCM30 port 9.
• the network management controller 10 is for the network organization and the OAM
• the network management controller 10 can access all system components for software and parameter download, system settings and queries and other OAM functions via the bus structure 11. Furthermore, communication with higher-level network and / or OAM organizational units via PCM30 port 9 is possible.
• the channel mapping module 12 is connected on the radio side via a data and address bus 13 to a number of CDMA digital processing modules 14 which provide CDMA channels (Code Division Multiple Access), with an addressed via the data and address bus 13 Access to the CDMA channels is possible.
• the channel mapping module 12 takes over in the downward direction (to the BTS access units 5) from the bus structure 11 a serial ATM cell stream which disorderly the user data for the connected BTS 4 and OAM and control data for downstream modules including the BTS -Access units 5 contains.
• the data are transferred to the CDMA digital processing modules 14 on the basis of a mapping rule, which includes which virtual channels of the ATM cell stream are to be assigned to which BTS access unit 5 and via which CDMA channels the transmission to the respective BTS access -Unit 5 has to be done.
• the channel mapping module 12 takes over the received data of the CDMA from the data and address bus 13.
• Each CDMA digital processing module 14 generates, for example, 16 CDMA channels, which represent the actual physical channels of the air interface 8.
• the CDMA digital processing modules 14 are connected to RF modules 16 via a data bus 15.
• the data bus 15 contains in the downward direction for each CDMA channel separate lines for the transmission data and in the upward direction lines for the received signal, which consists of the superimposition of the signals of all CDMA channels.
• Receiving devices of the RF modules 16 all work on a common one Antenna 17.
• the bus structure 11 allows up to 32 modules with the addresses 0 to 31 to be connected to them, a bidirectional sequential ATM cell stream from each module to every other being possible.
• adjustable transfer tables in each module determine which virtual channels are to be transmitted to which receiver modules on the bus structure 11.
• the BTS access unit 5 essentially comprises the same modules as that
• Radio base station 3 namely RF modules 18, which operate on a common antenna 19, a CDMA digital processing module 20, which is connected to the RF modules 18 by means of a data bus 21, a channel mapping module 22, which on the one hand uses a data and address bus 23 is connected to the CDMA digital processing module 20 and, on the other hand, by means of a further data and address bus 24 to a controller CTR 25 and a PCM30 interface module 26.
• the number of CDMA channels provided by the CDMA digital processing module 20 depends on the capacity requirements placed on the BTS access unit 5.
• the PCM30 interface module 26 has a PCM30 port 27, via which the coupling with the associated one BTS 4 of the mobile radio system takes place.
• the CTR 25 is the central controller of the BTS access unit 5 with regard to network organization and OAM functions and fulfills the tasks corresponding to the network management controller 10 of the radio base station 3, but is subordinate to it.
• FIG. 4 shows a block diagram of the PCM30 interface module 6.
• a PCM30 / E1 framer / controller 28 is arranged on the BSC side and is connected to a corresponding PCM30 port of the BSC 2 via a PCM30 interface 29.
• the PCM30 / E1 framer / controller 28 is connected to a microcontroller 31 via a processor port 30, the initialization,
• the PCM30 / E1 framer / controller 28 comprises an HDLC block, not shown, by means of which the data of a freely selectable timeslot can be written into a first register and transferred to the microcontroller 31. Furthermore, there is the possibility of entering data from the microcontroller 31 via the processor port 30 into a second register in the HDLC block, which are fed in in the opposite direction in the selected timeslots.
• the registers are designed as first-in / first-out registers.
• a demultiplexer 32 is arranged in the downward direction and is connected to the PCM30 / E1 framer / controller 28 via a PCM bus 33.
• the demultiplexer 32 has a multiplicity of outputs 34, each output 34 being assigned to a specific BTS 4.
• the demultiplexer 32 has the task of assigning the respective time slots, which are determined for a specific BTS 4, to the corresponding output 34.
• a multiplexer 35 is arranged in the upward direction and is connected to the PCM30 / E1 framer / controller 28 via a PCM bus 36.
• the multiplexer 35 has a multiplicity of inputs 37, each input 37 being assigned to a specific BTS 4.
• the multiplexer 35 has to classify the object, each of 'a BTS 4 incoming data in the time slots of the PCM bus 36th Demultiplexers 32 and multiplexers 35 perform this task on the basis of a configurable common allocation table and are connected to microcontroller 31 via a common processor port 38.
• the assignment table, initialization, parameterization and monitoring of multiplexer 35 and demultiplexer 32 are transferred along the path. Furthermore, there are a number of AAL1 segmentation / reassembling devices 39, each AAL1 segmentation / reassembling device 39 being assigned to a specific BTS 4. Each AAL1 segmentation / reassembling device 39 has one
• AAL1 segmentation / reassembling devices 39 are connected to a Cellbus interface device 44 via a UTOPIA 42, 43.
• a UTOPIA arbiter 45 controls the data exchange between the AAL1 segmentation / reassembling devices
• UTOPIA arbiter 45 is for this purpose Several control lines 46 each are connected to the AAL1 segmentation / reassembling devices 39 and via several control lines 47 to the Cellbus interface device 44.
• UTOPIA Universal Test and Operation Interface for ATM
• AAL1 Physical layer element
• Segmentation / reassembling device 39 with an ATM layer element (here Cellbus interface device 44).
• Each of the AAL1 segmentation / reassembling devices 39 is connected to the microcontroller 31 via a respective processor port 48.
• the ATM header data, initialization, parameterization, monitoring and the like are transferred via this path.
• the microcontroller 31 is connected to the Cellbus interface device 44 via a processor port 49.
• the initialization, parameterization, monitoring and the like of the Cellbus interface device 44 take place via this path.
• the microcontroller 31 can communicate via this path and the bus structure 11 with other system components, in particular the network management controller 10, and from there it communicates with the data for the configuration of the module.
• FIG. 5 a shows a PCM frame with a data structure 50 to be transmitted with a length of 4 timeslots, which is defined by TX-Structure Start and Structure size, where TX-Structure start is the number of the timeslot of the first octet and structure size indicates the number of octets or timeslots of the data structure. If the data structure 50 is not contiguous, then an additional structure
• This processing level is referred to as the physical layer.
• 5c shows the segmentation as it is carried out in accordance with AAL1 (ATM adaptation layer 1) in the AAL1 segmentation / reassembling devices 39, AAL1 being an algorithm defined by the ATM forum.
• SAR-PDU's 52 Segmentation and Reassembly Sublayer-Protocol Data Unit
• SAR-PDU's 52 Segmentation and Reassembly Sublayer-Protocol Data Unit
• SAR-PDU's 52 Segmentation and Reassembly Sublayer-Protocol Data Unit
• the Structure Pointer SP 54 indicates at which point of the following user data a structure begins.
• the structure pointer SP 54 thus appears only at relatively large intervals, so that the receiving side must have an a priori structure definition in order to be able to regenerate the structure between two SP 54 structure pointers.
• This processing level is called the ATM adaptation layer.
• the method of transmission as structured data described here ensures a low number of AAL1
• Segmentation / reassembling facilities 39 and short packaging times Since at least 2 timeslots are required to supply a BTS 4 and two octets are thus generated within a PCM30 frame with a duration of 125 ⁇ s, a SAR-PDU 52 is filled after approx. 3 ms.
• the packaging times are inversely proportional to the number of timeslots.
• the data of the SAR-PDUs 56 prepared in this way are supplemented according to FIG. 6d in the AAL1 segmentation / reassembling devices 39 with the ATM cell header 57 with a length of 5 octets, so that a complete ATM cell with 53
• the ATM cells are transferred to the Cellbus interface device 44 via the UTOPIA interface 42 and sent from there to the bus structure 11.
• the receiving end here the PCM30 interface module of the BTS access unit 5
• the receiving end does this data procedure in an AAL1 Segmentation / Reassembhng device reversed in reverse order, namely separation of the ATM cell header, extraction of the user data from the SAR-PDU 56, generation of the data stream according to FIG. 5b and transfer of this data stream to a multiplexer.
• the multiplexer of the receiving device adds this Data back into a PCM frame
• this multiplexer must again have a structure definition which describes the classification in a PCM frame according to a priori agreement, namely TX structure start and structure size, which is shown in FIG. 5e for a coherent data structure
• TX structure start and structure size which is shown in FIG. 5e for a coherent data structure
• send and receive structure definitions can differ from one another be independent, ie an offset can be selected between the sending and receiving sides.
• a structure definition with TX structure start, structure size and structure description could be stored in accordance with FIG. 5f in order to be classified into the time slots according to special requirements
• FIGS. 6a-d The processing of the OAM data in the downward direction is shown in FIGS. 6a-d.
• FIG. 6a a PCM frame is shown in which the timeslot Tsn 58 for the transmission of the OAM is shown as an example Data is used.
• FIG. 6b shows a section of the flow of the data selected over several PCM frames, which are sent for further processing. If no OAM data are to be transmitted at the time, so-called idle flags are stored in the PCM timeslot 59 transmitted.
• the start of a message 60 is characterized by an octet not equal to an idle flag 59. Accordingly, the end of a message 61 is characterized by the occurrence of an idle flag 59.
• Messages of different lengths can occur, but two messages can be identified by at least one Flag 59 are separated by special
• Bitstaffing ensures that no data occurs within a message correspond to the idle flag 59.
• the segmentation is shown how this is carried out in accordance with AAL5 (ATM adaptation layer 5) in the microcontroller 31.
• the idle flags 59 are discarded by the microcontroller 31 and a message is inserted into a SAR PDU 63 as a so-called SAR-PDU payload 62.
• a SAR-PDU trailer 64 with a length of 8 octets is added and then the SAR-PDU payload 62 is supplemented with so much PAD (padding field) that the overall length of the SAR-PDU 63 is n * 48 octets.
• the SAR-PDU 63 is then broken down into blocks of 48 octets each.
• the SAR-PDU Trailer 64 contains an indication of the length of the message, which again enables a receiving unit
• This processing level is called the ATM adaptation layer.
• the 48 octet long partial blocks of the SAR-PDU 63 prepared in this way are supplemented in accordance with FIG. 6d in the microcontroller 31 with the ATM cell headers 65 with a length of 5 octets, so that complete ATM cells with 53 octets are created.
• the ATM cell header 66 of the last cell is given a label which identifies this cell as the last cell of a SAR-PDU 63.
• This processing level is referred to as the ATM layer.
• the ATM cells are transferred from the microcontroller 31 via the processor port 49 to the Cellbus interface device 44 and sent by the latter to the bus structure 11.
• the receiving side here the network management controller 10 according to FIG. 2, reverses these data procedures in an AAL5 segmentation / reassembling process in reverse order, namely separation of the ATM cell header, removal of the user data from the SAR-PDU 63, reassembling the Message and delivery of the message to the processing entity.
• Processes are implemented in the network management controller 10 in the same way as in the PCM30 interface module 6. The only difference is that the processing instance is implemented in software in the same controller that also performs the AAL5 segmentation / reassembling in the network management controller 10. Reference list

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
• Data Exchanges In Wide-Area Networks (AREA)

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Citations (3)

• 1997
  • 1997-08-28 DE DE19737528A patent/DE19737528C2/de not_active Expired - Fee Related
• 1998
  • 1998-08-24 EP EP98951197A patent/EP1010343A1/de not_active Withdrawn
  • 1998-08-24 WO PCT/DE1998/002468 patent/WO1999012368A1/de not_active Application Discontinuation
  • 1998-08-24 AU AU97347/98A patent/AU9734798A/en not_active Abandoned
  • 1998-08-27 ZA ZA9807778A patent/ZA987778B/xx unknown

Patent Citations (3)

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