Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W92/00—Interfaces specially adapted for wireless communication networks
  • H04W92/16—Interfaces between hierarchically similar devices
  • H04W92/22—Interfaces between hierarchically similar devices between access point controllers
• • 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
  • H04W88/12—Access point controller devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W92/00—Interfaces specially adapted for wireless communication networks
  • H04W92/02—Inter-networking arrangements

Definitions

• the invention relates to a personal tele- communications system (PCS) based on a fixed telecommunications network, such as a Public Switched Telephone Network, having a mobile communications system as an access network, connected to a local exchange.
• PCS personal tele- communications system
• PCS Personal Communication System
• GSM based PCS1900 a GSM system operating within the frequency range of 1900 MHz
• Modification of an existing mobile communication standard (such as GSM or DCS1800) to a PCS-overlay network is a relatively straightforward process. Instead, more problems will be caused by PCS networks similar to the fixed ISDN and PSTN networks, employing a standard local exchange (LE) of the fixed network instead of a mobile services switching centre, such as an ISDN/PSTN based network is not directly compatible with the GSM network architecture.
• the mobile services switching centre is the central entity of the network in a GSM based overlay network.
• the local exchange LE does not have any functions supporting the mobile communication network.
• the local exchange LE may be assumed to include a small set of general functions that support switching of mobile communication networks (non-call related signalling, handover switching support of some kind) , but they are not necessarily very useful for meeting the requirements of the PCS1900 system, for instance.
• the radio interface is a wireless access communication system ACS (Bellcore TR INS-001313), which is connected to the local exchange of a fixed network.
• An intelligent network is connected to the local exchange, providing the local exchange with the service logic, the databases and the operations required for the mobility management of the access network.
• an AIN network Advanced Intelligent Network
• the basic features of call control are located in an ISDN local exchange, from which call control can initiate intelligent network operations in accordance with predetermined triggers via a ' standard AIN interface.
• the Bellcore system also supports handover, which is referred by Bellcore to as "Automatic Link Transfer" (ALT) .
• ALT Automatic Link Transfer
• the aim of ALT is to ensure the continuity of a service to the user when the signal strength varies during an answered call. The signal strength may vary e.g. if a PCS user is moving, or if the conditions of the radio environment change.
• ALT The aim of ALT is to enable the continuity of an answered ongoing call without interruption, and without the user taking any measures for performing an ALT or being aware of the fact the ALT has taken place.
• Chapter 3, pp. 133 to 138 of the above-mentioned document discloses an ALT procedure in which a local exchange operates as the "anchor point" of handover.
• IPS/RPCU old base station system
• IPS/RPCU new base station system
• the local exchange for the fixed network is the anchor point of switching and signalling.
• the handover employing the local exchange as the anchor point may be carried out in new national ISDN exchanges having the required features.
• This handover concept cannot be considered as an appropriate way of proceeding, particularly at the initial stage of the PCS systems, because most of the existing exchanges of the fixed network represent the older type, and it is not possible to guarantee the availability of exchanges that have the required features.
• problems are caused by the fact that a network element incompatible with the access network standard, such as the GSM, is used as the anchor point of handover connections. Disclosure of the Invention
• the object of the present invention is a telecommunications system in which the control of the radio network access network is as independent of the features of the fixed local exchange as possible.
• a telecommunications system comprising a local exchange of a fixed network, mobile stations, base station systems providing the mobile stations a wireless access network to the local exchange, each base station system comprising a base station controller and a plurality of base stations.
• the method is characterized in that location management, radio resources manage ⁇ ment and/or handover control are concentrated in a group of two or more base station systems in one master base station controller, which controls the other base station controllers of the group.
• the highest level network element controlling the radio path is the base station controller.
• the base station controller may be, however, too small a unit for location management, radio resources control, and/or handover control, for instance.
• these features are concentrated in a group of base station controllers in one master base station controller, which controls the other base station controllers of the group, lacking the above-mentioned features.
• FIG. 1 is a block diagram illustrating an ISDN-based PCS network in accordance with the invention
• Figure 2 is a block diagram illustrating dividing the functions of a mobile services switching centre into functional units, and allocating them to different network elements.
• the access network is a radio system based on the GSM system, such as PCS1900.
• the access network is modified from the GSM mobile communications system or its 1800-MHz version DCS1800.
• the block diagram of Figure 1 illustrates the network elements of the access network PCS1900 connected to the fixed network.
• the access network PCS1900 comprises base station systems BSS each comprising one base station controller BSC, and a plurality of base stations BTS.
• Base stations BTS communicate over the radio interface with personal stations PS (mobile stations) .
• the radio interface between a personal station PS and a base station BTS, as well as the interface between the base station BTS and the base station controller BSC are similar to those in a conventional overlay PCS1900 system, and they are not paid closer attention to herein.
• base station controllers BSC are not connected to the mobile services switching centre MSC, but to the local exchange LE of a fixed network, such as ISDN or PSTN.
• the local exchange is an ISDN exchange.
• the local exchange LE is connected to a service control point SCP of the advanced intelligent network AIN through a standard intelligent network connection.
• the intelligent network is not required.
• the local exchange itself may contain more intelligent functions.
• the local exchange LE may be connected to the other local exchanges LE or trunk exchanges TX of the ISDN network, as normally.
• a PCS network based on a fixed network is thus not directly compatible with the GSM architecture, as there is no mobile services switching centre MSC.
• the mobile services switching centre MSC is the central unit of the network, but the local exchange of a fixed network does not support all of the MSC functionality. Therefore, in the present invention, the functions of the mobile communications switching centre are divided into functional units, which are located in the base station controller BSC, except for the call control.
• the intelligent network AIN a function corresponding to the home location register HLR of the GSM system is provided, as well as part of a function corresponding to the visitor location register.
• BSC Base Station Controller Function
• BSCF+ Base Station Controller Function Additions: - divides the A-interface from the BSCF so that call control is assigned to LEF and other signalling to RSCF, carries out the switching operations related to handover (HO) acting as the anchor point for the switching operations, converts GSM based call control into ISDN call control,
• HO handover
• LEF local exchange function
• LEF includes the standard functions of an ISDN local exchange LE (National ISDN3 as a default) .
• LEF may also support non-call related (NCA) signalling from the base station system BSS to the service control point SCP.
• NCA non-call related
• RSCF radio system control function
• MSC mobile services switching centre
• RSCF radio resources
• RSCF is also an interface unit between the A-interface protocols and MAP protocols.
• HOF handover decision function
• VLRF visitor location register function
• VLR1F virtual location register function
• VLR2F virtual location register function
• the upper part VLR2F of the VLR is located in the service control point SCP of the intelligent network, and the lower part VLR1F in the access network, more precisely in the base station controller.
• SCF service control function
• SCF standard service control function SCF of the fixed network, providing the standard intelligent network services (AIN) .
• HLRF corresponding to the gateway-MSC situation
• VLRF local location interrogations
• VLRF co-operate with the VLRF for responding to AIN interrogations, etc.
• the HLRF home location register function
• the intelligent network comprises an EIRF (equipment identification register function) , and possibly an SMS-GI F (short message service gateway - interworking function) , which are not paid closer attention to herein.
• EIRF equipment identification register function
• SMS-GI F short message service gateway - interworking function
• FIG. 2 shows three BSC's, BSC1 operating as the master BSC, and BSC2 and BSC3 as the slave-BSC's.
• each BSC must contain a BSCF and a BCSF+ unit. Call control, that is, an LEF unit must be included in the local exchange LE.
• the other functional units handle signalling only, and they may therefore be allocated more freely.
• the other functional units are distributed to the network element in accordance with Figure 2:
• SCP contains units SCF and VLR2F;
• the master base station controller BSC1 contains an access manager AM containing units HOF and VLR1F.
• the entire VLRF may be located in the BSC or in the SCP.
• Base station controllers BSC2 and BSC3 are also through signalling connections 11 under control of the access manager AM of the master base station controller BSC1.
• the preferred embodiment of the invention further comprises a new, alternative signalling route 10, which bypasses the local exchange LE between the base station controller BSC and the service control point SCP. This makes signalling between the BSC and the HLR simpler.
• the signalling interfaces LE-BSC and SCP-BSC are termed as C-interfaces. Signalling of a C- interface may use non-call related signalling of the ISDN network, or, alternatively, the network of a Signalling System Nr 7 (SS7) for the PCS-related signalling between the base station controller BSC and the intelligent network AIN.
• SS7 Signalling System Nr 7

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

Applications Claiming Priority (3)

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• 1995
  • 1995-02-20 FI FI950776A patent/FI100081B/fi active
• 1996
  • 1996-02-14 KR KR1019970705722A patent/KR19980702325A/ko active IP Right Grant
  • 1996-02-14 CN CN96192032A patent/CN1176038A/zh active Pending
  • 1996-02-14 AU AU46664/96A patent/AU700054B2/en not_active Ceased
  • 1996-02-14 JP JP8525425A patent/JPH11500876A/ja active Pending
  • 1996-02-14 EP EP96902296A patent/EP0811297A1/en not_active Withdrawn
  • 1996-02-14 WO PCT/FI1996/000085 patent/WO1996026617A1/en not_active Application Discontinuation
  • 1996-02-14 CA CA002211136A patent/CA2211136A1/en not_active Abandoned
• 1997
  • 1997-08-19 NO NO973803A patent/NO973803D0/no not_active Application Discontinuation

Non-Patent Citations (1)

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