Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W36/00—Hand-off or reselection arrangements
  • H04W36/0005—Control or signalling for completing the hand-off
  • H04W36/0055—Transmission or use of information for re-establishing the radio link
  • H04W36/0066—Transmission or use of information for re-establishing the radio link of control information between different types of networks in order to establish a new radio link in the target network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W36/00—Hand-off or reselection arrangements
  • H04W36/0005—Control or signalling for completing the hand-off
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W36/00—Hand-off or reselection arrangements
  • H04W36/0005—Control or signalling for completing the hand-off
  • H04W36/0055—Transmission or use of information for re-establishing the radio link
• • 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
  • H04W92/20—Interfaces between hierarchically similar devices between access points

Definitions

• the present invention relates to a method and arrangement in a telecommunications system, in particular it relates to a method and arrangement for cell type information sharing in a telecommunications system.
• user equipments also known as mobile terminals and/or wireless terminals communicate via a Radio Access Network (RAN) to one or more core networks.
• RAN Radio Access Network
• the user equipments can be mobile stations or user equipment units such as mobile telephones also known as "cellular" telephones, and laptops with wireless capability, e.g. mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-included, or car-mounted mobile devices which communicate voice and/or data with radio access network.
• the radio access network covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a Radio Base Station (RBS), which in some networks is also called “eNB", “NodeB” or “B node” and which in this document also is referred to as a base station.
• a cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site.
• the base stations communicate over the air interface operating on radio frequencies with the user equipment units within range of the base stations.
• radio network controller In some version of the radio access network, several base stations are typically connected, e.g., by landlines or microwave, to a Radio Network Controller (RNC) .
• the radio network controller also sometimes termed a Base Station Controller (BCS) , supervises and coordinates various activities of the plural base stations connected thereto.
• the radio network controllers are typically connected to one or more core networks.
• the radio access technologies for cellular mobile networks are continuously being evolved to meet the future demands for higher data rates, improved coverage and capacity.
• Examples of recent evolutions of the WCDMA access technology are HSPA (High-Speed Packet Access) .
• HSPA High-Speed Packet Access
• 3G Long Term Evolution LTE
• 3GPP 3rd Generation Partnership Project
• All these functions require certain information about the characteristics and role of the neighbouring cells, information which could be provided to a base station, sometimes called NodeB or eNodeB, as part of information on a handover of a mobile terminal, sometimes called UE or mobile station e.g. together with UE History Information. This however involves collecting a lot of statistical handover information as well and is not an especially quick or flexible procedure.
• Cell type has been defined in 3GPP specification often as: macro, micro, pico, femto [I]; large, (medium), small [2]; wide area, (medium area), local area [3],
• the size of the cell coverage area and the cell hierarchy level may but are not necessarily coupled, e.g. two cells may both have large coverage area but depending on the purpose in the radio network, those two cells may belong to different level in cell hierarchy.
• a first aspect of the present invention relates to a method in a first radio base station serving a first cell in a wireless communication system, for informing a second radio base station serving a second cell that has a neighbour relation with the first cell, of at least the cell type of the first cell.
• a first method step of the first aspect of the invention involves adding the cell type to a set of information to be signaled to the second base station.
• a second method step of the first aspect of the invention involves signalling the set of information to the second base station.
• the information is signaled over an X2 interface.
• the information is signaled during an X2 setup procedure and/or an eNodeB Configuration Update procedure.
• a further embodiment of the first aspect involves also or alternatively adding information of the cell types of other cells having a neighbour relation with the first cell to the set of information to be signaled to the second base station.
• Another embodiment of the first aspect involves in return receiving in the first base station, information on the cell type of the cell served by the second base station.
• the return information may in yet another embodiment of the first aspect also or alternatively include the cell types of other cells having a neighbour relation with the second cell served by the second base station.
• the cell type information i.e. cell size and hierarchical level, is for use by at least one of the first and second base station in handover evaluation of a specific UE.
• a second aspect of the present invention relates to a first radio base station serving a first cell in a wireless communication system capable of exchanging cell type information including cell size and hierarchical level with a second base station serving a second cell that has a neighbour relation with the first cell, wherein the base station comprises means arranged to perform the method according to the first aspect of the invention.
• the present invention provides the advantage that a base station, such as an eNodeB, quickly and without collecting extra statistical handover information from a UE is updated with the cell type of a neighbour cell, something which is useful for at least one of:
• Fig. 1 is an example illustration of cell type information exchange via an X2 setup procedure.
• Fig. 2 illustrates a cell type information exchange via an eNodeB Configuration Update procedure.
• Fig. 3 is a schematic illustration of neighbour base stations exchanging cell type information.
• Fig. 4 is a logic flew diagram of one embodiment of a method for exchanging cell type information.
• Fig. 5 is a block diagram of one embodiment of a base station configured to exchange cell type information.
• inventive methods and apparatus are described in the context of an LTE/SAE wireless network.
• many of the control functions described herein reside in an eNodeB 310.
• inventive techniques described herein are applicable to other network types and other network configurations.
• inventive methods and apparatus disclosed herein may be applicable to an evolved High-Speed Packet Access (HSPA) architecture, in which the Radio Network Controller (RNC) is integrated into the NodeB, as well as to a Release 99
• HSPA High-Speed Packet Access
• RNC Radio Network Controller
• GERAN/UTRAN architecture in which the neighbor cell type information described below might be transferred between peer control nodes (e.g., RNCs and/or Base Station Controllers).
• peer control nodes e.g., RNCs and/or Base Station Controllers.
• the present invention involves a method and arrangement for exchanging cell type information between network nodes serving neighbour cells, such as base stations for example eNodeB base station, of a telecommunications system wherein the neighbour cell type information is added to the served cell information and/or to the neighbour information signaled between the neighbour base stations.
• neighbour cells such as base stations for example eNodeB base station
• Fig. 3 schematically illustrates a cell type information exchange between neighbour base stations in an LTE/SAE network 300.
• each base station 310, 330 serves a respective cell 320, 330, which have a neighbour relation as being direct neighbors, i.e. in direct proximity and, in this example overlapping each other. It is possible but not required for cells of neighbor or proximate base station to overlap, or even the one cell to be fully encompassed in the other, to be considered as neighbor cells. Cells may also be considered neighbors when having their respective cell edges at a distance from each other leaving a non-served space there between, i.e. providing an area with no cell coverage.
• Fig. 4 thus provides an illustration of an exemplary method for cell type information sharing between base stations, as might be implemented, for example, in an eNodeB 310 of an LTE/SAE wireless communication system.
• Those skilled in the art will appreciate that some steps illustrated in Fig. 4 may be omitted. Furthermore, steps may be performed in a different order than shown.
• the method of Fig. 4 "begins" at block 410, where cell type information such as cell size and/or cell hierarchical level data for cells served by the (first) base station, for example eNodeB 310, is added to a list of its served cells to be signaled to a neighbor (second) base station, such as eNodeB 330.
• the cell type information is added to a set of information in a message to be signaled to the neighbor base station, such as an X2 setup request message or an eNodeB configuration update message.
• the cell type information is provided in the form an information element IE such as a Neighbor Information IE comprising a Cell Type IE or a Served Cell IE comprising cell configuration information including Cell Type IE.
• the Cell Type IE indicates respective cell characteristics of the served cells such as one or both of cell size and cell hierarchical level.
• the cell type information could also or alternatively include other cell characteristic data such as a flag or indicator for indicating if a cell is providing service to a closed subscriber group or to all users of the mobile network.
• the cell type information is signaled to the neighbor base station, such as eNodeB 330, over an X2 interface.
• the signaling could then be provided as part of an X2 setup procedure or eNodeB configuration update procedure.
• the neighbor (second) base station for example eNodeB 330, responds by transmitting in return a list of its served cells with corresponding cell type information defined for each listed cell. This list or cell type information is received in the (first) base station at block 430.
• cell type information of direct neighbors of the first and/or second base station is added to the set of information signaled.
• the cell type information is exchanged over an Sl interface in a corresponding way to that described for the X2 interface.
• the present invention enables neighbour base stations, such as eNodeBs 310 and 330, to exchange necessary cell characteristics over the X2 interface 360 using X2AP, X2 Setup and/or eNB Configuration Update procedures instead of basing any decisions of (neighbour) cell characteristics on the information provided e.g. with UE History Information.
• X2 Setup and/or eNB Configuration Update One advantage of having the cell characteristics at X2 Setup and/or eNB Configuration Update is that the base stations do not have to collect statistical information from the handovers of each individual mobile terminal, i.e. UE. However, the cell type is not currently, see ref.
• 3GPPTS36.423v8.3.0 among cell information signaled to the neighbouring base stations or eNodeBs while the knowledge of cell type (the level of the neighbour cell in radio network hierarchy and the size of the neighbour cell) are important for functions like inter cell load balancing, inter cell interference coordination, optimisation of mobility control (in case of hierarchical cell structures), distributed physical cell identity allocation/selection, etc.
• the cell type information could be useful to exchange before any statistics provided per UE is available or when the UE History information could not be trusted (e.g. in a multivendor environment) , namely:
• the cell size is an important characteristic also for handover optimization of fast moving UEs where one option would be to keep the UE on the same size or larger cell where the cell changes could be less frequent.
• PCI selection/allocation The important aspect for PCI selection are the cell size because of it has direct relation to the number of neighbour cells this particular cell has and the cell hierarchy level as it defines the type of neighbour relation in the hierarchy.
• the PCI selection/allocation algorithm may assign different PCI reuse factors for each cell size and cell hierarchy level combination, Similar to the previous example, in case of homogenous network where macro cell refers to high hierarchy and large cell size, micro cell to medium hierarchy and medium cell size, etc then macro, micro, pico and femto would be sufficient.
• the PCI selection/allocation algorithm may not be able to produce desirable outcome (there could be too many cells that result in PCI confusion, i.e. the source eNB could not uniquely identify the target cell only based on the PCI) .
• the cell types macro, micro, pico and femto can also be used for optimised radio resource management.
• Cell Type information could be used for radio resource management:
• one option would be to keep the UE that is moving fast on the same size cell/hierarchy level cell or larger cell/lower hierarchy level cell (where the cell changes would be less frequent) .
• another option would be to keep the UE that is moving slowly or not at all on the same size cell/hierarchy level cell or smaller cell/higher hierarchy level cell.
• definition of the cell hierarchy could change and/or the cells on one hierarchy level may have significantly different size
• definition ([1] through [3] separately would not provide sufficient information about the topology change.
• Such a network could e.g. be at the border of a dense urban area and an urban area.
• a cell type definition that explicitly provides information about cell hierarchy level and cell size is the only option to detect the change in the radio network topology.
• This example served cell information element IE comprises cell configuration information of a cell including a cell type IE that a neighbour base station, such as an eNodeB, may need for the X2 AP interface.
• Fig. 1 is illustrated an example embodiment of a successful cell type information exchange via a X2 setup procedure
• an eNodeB base station eNBi initiates the procedure by sending 110 an X2 SETUP REQUEST message, e.g. the example X2 SETUP REQUEST message of below, to a candidate eNodeB base station eNB 2 .
• Candidate eNodeB replies 120 with an X2 SETUP RESPONSE message, e.g. the example X2 SETUP RESPONSE message of below.
• the initiating eNodeB transfers a list of served cells to the candidate eNodeB.
• Candidate eNodeB replies with a list of its served cells.
• the initiating eNodeB may include the Neighbour Information IE in the X2 SETUP REQUEST message.
• the candidate eNodeB may also include the Neighbour Information IE in the X2 SETUP RESPONSE message where the Neighbour Information IE may contain the Cell Type IE.
• the Neighbour Information IE shall only include cells that are direct neighbours of cells in the reporting eNodeB.
• Fig. 2 is illustrated an example embodiment of a successful cell type information exchange via an eNodeB Configuration Update procedure where the first eNodeB base station eNBi initiates the procedure by sending 210 an ENB CONFIGURATION UPDATE message, e.g. the example ENB CONFIGURATION UPDATE message of below, to a peer eNodeB base station eNB ⁇ .
• eNB 2 Upon reception of an ENB CONFIGURATION UPDATE message, eNB 2 shall update the information for eNB 1( for example as follows: Update of Served Cell Information: If Served Cells To Add IE is contained in the ENB CONFIGURATION UPDATE message, eNB 2 shall add cell information according to the information in the Served Cell Information IE.
• eNB 2 shall modify information of cell indicated by Old ECGI IE according to the information in the Served Cell Information IE.
• eNB 2 shall delete information of cell indicated by Old ECGI IE.
• eNB 2 shall add the GU Group Id to its GU Group Id List. If GU Group Id To Delete List IE is contained in the ENB CONFIGURATION UPDATE message, eNB 2 shall remove the GU Group Id from its GU Group Id List.
• Neighbour Information IE is contained in the ENB CONFIGURATION UPDATE message, eNB 2 may use this information to update its neighbour cell relations, or use it for other functions, like PCI selection.
• the Neighbour Information IE shall only include cells that are direct neighbours of cells in the reporting eNB.
• the Neighbour Information IE may contain the Cell Type IE.
• eNB 2 After successful update of requested information, eNB 2 shall reply 220 with an ENB CONFIGURATION UPDATE ACKNOWLEDGE message to inform the initiating eNBi that the requested update of application data was performed successfully.
• the peer eNB 2 receives an ENB CONFIGURATION UPDATE without any information element, IE, except for Message Type IE it should reply with ENB CONFIGURATION UPDATE ACKNOWLEDGE message without performing any updates to the existing configuration.
• This message is sent by a base station, such as a first eNodeB, to a neighbouring base station, such as a second eNodeB, to transfer the initialization information for a Transport Network Layer, TNL, association.
• a base station such as a first eNodeB
• a neighbouring base station such as a second eNodeB
• This return message is sent by a base station such as a second eNodeB to a neighbouring base station such as a first eNodeB to transfer the initialization information for a TNL association.
• This message is sent by an eNB to a peer eNB to transfer updated information for a TNL association.
• the proposed way of defining cell type allows future additions of cell characteristics/ roles, etc.
• One such example could be a flag indicating if a cell is providing service to closed subscriber group or to all users of the mobile network.
• an exemplary base station 500 that may be used to implement one or more of the methods described herein is pictured.
• the illustrated base station 500 is just one example of a control node for implementing the methods described herein.
• Many of the functions of control processor 510 may be implemented using a separate device, which might be co-located with conventional base station equipment or located remotely from the base station.
• the control node functionality may be part of an eNodeB in an LTE/SAE system, for example, or may be a separate control function in any other network.
• the control node functionality may be part of a radio network controller (RNC) or a base station controller.
• RNC radio network controller
• a control function may be associated with a single base station or several base stations.
• the exemplary base station 500 of Fig. 5 includes a processing unit 510 configured for communication with one or more mobile stations using radio transceiver circuitry 520 and antenna 525.
• Base station 500 further includes a network interface 570 for communication with other elements of a wireless network, including, in some embodiments/ other base stations 500 and access gateways such as the LTE/SAE access gateways.
• base station 500 may comprise an eNodeB for use in an LTE/SAE wireless communication system, but the inventive methods and apparatus described herein are applicable to other wireless network standards and other network configurations as well.
• radio transceiver circuitry 520 and portions of the processing unit 510 are configured to comply with one or more wireless telecommunications standards, such as those promulgated by 3GPP.
• baseband signal processor 530 may be configured to encode and decode signals in accordance with 3GPP LTE standards defining physical layer protocols for Orthogonal Frequency Division Multiple Access (OFDMA) -based downlink signals and Single Carrier Frequency Division Multiple Access (SC-FDMA) uplink signals .
• OFDMA Orthogonal Frequency Division Multiple Access
• SC-FDMA Single Carrier Frequency Division Multiple Access
• Processing unit 510 includes, in addition to baseband signal processor 530, a radio resource manager 540, mobility manager 550, other control processing 555, and memory 560, which in turn comprises a program store 562 and other data needed for operation of the base station 500, including a list of served cells with respective cell type information 564. Here also cell type information of neighbor cells may be stored.
• Fig. 5 depicts a functional representation of the elements of processing unit 510. Accordingly, each of the pictured processing blocks may in some embodiments directly correspond to one or more commercially available or custom microprocessors, microcontrollers, or digital signal processors.
• memory 560 is representative of the one or more memory devices containing the software, firmware, and data used to implement base station functionality in accordance with one or more embodiments of the present invention.
• memory 560 may include, but is not limited to, the following types of devices: cache, ROM, PROM, EPROM, EEPROM, flash, SRAM, and DRAM.
• Base station 500 may be configured to implement one or more of the methods described herein for exchanging neighbour cell type information. Accordingly, processing unit 510 may be configured to both transmit and in return receive a set of information including cell type information such as cell size and cell hierarchical level, from a neighbour base station in association with a X2 Setup and/or an eNB Configuration Update procedure. The neighbour cell type information is then exchanged through network interface 570, which in an LTE system may comprise an X2 interface, such as an X2AP, as defined by 3GPP specifications.
• network interface 570 which in an LTE system may comprise an X2 interface, such as an X2AP, as defined by 3GPP specifications.
• the neighbour cell type information could alternatively be exchanged over an Sl interface as defined by 3GPP specifications, for example incorporated in the information signaling required for a corresponding Sl setup or eNB configuration update procedure.
• the processing unit 510 is further configured to add the cell type data to the setup request (X2 or Sl) or eNB configuration update message; this cell type data may include cell size data, cell hierarchical level data as described earlier and/or other cell characteristic daza such as a flag or indicator for indicating if cell is providing service to closed subscriber group or to all users of the mobile network.
• Processing unit 510 is further configured to transfer the message to a neighbour base station in association with an X2 or Sl Setup and/or eNB Configuration Update procedure.
• processing unit 510 may be configured to receive in return from the neighbour base station its corresponding cell type information in an X2 or Sl setup response message or in an eNB configuration update acknowledgement message.
• the corresponding cell type information of direct neighbors of both the initiating base station 500, such as the base station 310 of Fig. 3, and the candidate neighbour base station, such as base station 330 of Fig. 3, is included in the above described messaging exchange.
• Computer program code for carrying out operations of the various control nodes discussed above with respect to Figures 1 - 5 may be written in a high-level programming language, such as Java, C, and/or C++, for development convenience.
• computer program code for carrying out operations of embodiments of the present invention may also be written in other programming languages, such as, but not limited to, interpreted languages.
• Some modules or routines may be written in assembly language or even micro-code to enhance performance and/or memory usage. It will be further appreciated that the functionality of any or all of the program modules may also be implemented using discrete hardware components, one or more application specific integrated circuits (ASICs) , or a programmed digital signal processor or microcontroller.
• ASICs application specific integrated circuits
• These computer program instructions may be provided to a processor of a general purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart and/or block diagram block or blocks.
• These computer program instructions may also be stored in a computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instructions that implement the function specified in the flowchart and/or block diagram block or blocks.
• the computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart and/or block diagram block or blocks.
• a radio base station also called NodeB or eNodeB
• UE mobile terminal
• Means mentioned in the present description can thereby be software means, hardware means or a combination of both.

Landscapes

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

Priority Applications (5)

Applications Claiming Priority (2)

Related Child Applications (2)

Publications (1)

Family

ID=42129057

Family Applications (1)

Country Status (4)

Cited By (15)

Families Citing this family (59)

Citations (5)

Family Cites Families (19)

• 2009
  • 2009-10-26 EP EP09823905.6A patent/EP2340671B1/en active Active
  • 2009-10-26 WO PCT/SE2009/051220 patent/WO2010050885A1/en not_active Ceased
  • 2009-10-26 US US13/126,034 patent/US8254982B2/en active Active
  • 2009-10-26 JP JP2011534447A patent/JP5492218B2/ja not_active Expired - Fee Related
• 2012
  • 2012-07-23 US US13/555,549 patent/US8774854B2/en not_active Expired - Fee Related
• 2014
  • 2014-02-28 JP JP2014039201A patent/JP5806353B2/ja active Active
  • 2014-06-04 US US14/295,444 patent/US9226204B2/en not_active Expired - Fee Related

Patent Citations (5)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events