Self configuring and optimisation of cell neighbours in wireless telecommunications networks

Abstract

The present invention relates to a cellular communications network and in particular to the problem of identifying cells for neighbour lists, or handover candidates when the cells are identified by a limited number of non-unique identities. The present invention includes a method for a radio base station, wherein the base station receives reports from one ore more terminals in neighbour cells quality and non-unique identities. The match is sought in a neighbour cell list non-unique identity with a unique cell identity. If the match cannot be made without ambiguity, the base station orders the terminal to detect the unique cell identity. If the reason for the ambiguity is the particular cell is not included in the neighbour cell it is included when its unique identity has been established. The uniquely identified cell is used if a handover is decided.

1 . A method for a radio base station or for a base station controller connected to a radio base station and controlling it wherein the radio base station serves a first cell of a plurality of cells in a wireless telecommunications system, the method comprising the steps of:
 communicating with a mobile terminal in the first communications cell;   receiving from the mobile terminal a quality measure on a second cell and a non-unique identification of the second cell;   retrieving a neighbour cell list for the first cell, to match a unique-cell identification with the non-unique cell identity, and if ambiguity in the match arises instructing the mobile terminal to determine the unique cell identity of the second cell;   receiving unique cell identifier information relating to the second communications cell from the mobile terminal; and   associating the non-unique cell identity with the unique cell identity.   
     
     
         2 . A method as claimed in  claim 1 , wherein ambiguity arises when the second cell non-unique identity is not included in the neighbour cell list. 
     
     
         3 . A method as claimed in  claim 1 , wherein ambiguity arises if the second cell non-unique cell identity is included in the neighbour cell list with information on suspected ambiguity of identification. 
     
     
         4 . A method as claimed in  claim 1 , wherein ambiguity arises if two unique cell identities in the list shares the same non-unique cell identity. 
     
     
         5 . A method as claimed in  claim 2 , wherein in said associating step said second cell non-unique and unique cell identities is added to the neighbour cell list. 
     
     
         6 . A method as claimed in  claim 3  or  4 , wherein in said associating step said second cell non-unique and unique cell identities is associated with the communication with the terminal for a period. 
     
     
         7 . A method as claimed in  claim 3  or  4 , wherein in said associating step said second cell non-unique and unique cell identities are associated with the communication with the terminal as long as the quality measure exceeds a first threshold level 
     
     
         8 . A method as claimed in  claim 3 , wherein information on suspected ambiguity is added to a non-unique cell identity if one or more handovers from the first cell to a cell with the non-unique cell identity has/have been unsuccessful. 
     
     
         9 . A method as claimed in  claim 1 , wherein the quality measure is at least one of;
 signal strength measurement, a signal quality measurement, or timing information.   
     
     
         10 . A method as claimed in  claim 1 , wherein the instructing step is performed on the further condition of the second cell quality measure exceeds a second threshold value. 
     
     
         11 . A method as claimed in  claim 1 , wherein the instructing step is performed on the further condition the second cell is determined to be a handover candidate. 
     
     
         12 . A method as claimed in  claim 1 , comprising the further steps of:
 broadcasting a non-unique identity of the first cell, in a first information layer intended for carrying information for supporting the physical connection with the terminals;   broadcasting a unique identity of the first cell on an information layer higher then the first layer.   
     
     
         13 . A radio base station for providing communication in a first cell with at least one terminal and comprising:
 a radio transceiver;   a controller including or being connected to a database that includes a neighbour cell list and including a NCL utility, the controller being arranged for receiving via the transceiver reports from the terminal on measured reception quality on other cells than the first cell, including the other cells non-unique cell identities, further arranged for matching the non-unique cell identities with corresponding unique cell identities by retrieving the neighbour cell list, the NCL utility arranged for initiating an instruction being sent to the terminal for identifying and reporting on the unique cell identity of a non-uniquely identified cell if ambiguity arises in the matching, the NCL utility further being arranged for associating the non-unique cell identity and the unique cell identity as reported by the terminal  14 . A method for a mobile terminal,  4 , in a cellular telecommunications network, the method comprising:   communicating,  301 , over a first link in a first cell;   measuring,  302 , a signal quality of a channel broadcasted in a second cell;   detecting,  303 , a non-unique cell identity broadcasted in the second cell:   reporting,  304 , the measured second cell signal quality and the identified non-unique identity over the first radio link;   receiving,  305 , an instruction over the first radio link to detect a second cell unique identity;   detecting,  306  the unique cell identity broadcasted in the second cell;   reporting,  307 , the unique second cell identity by transmission over the first radio link.   
     
     
         15 . The method of claim  14 , wherein the non-unique second cell identity is detected in a first layer carrying physical information. 
     
     
         16 . The method of claim  14 , wherein the unique second cell identity is detected in a second layer higher than the first layer. 
     
     
         17 . A mobile terminal for communicating with a first radio base station in a first cell and performing measures on the reception quality from other cells, and comprising:
 a radio transceiver,   a controller arranged for identifying a non-unique cell identity of the respective other cells and report to the first radio base station with the quality measures, and further arranged for controlling the transceiver to identify a unique cell identity of one or more of the other cells in response to an instruction received from the first radio base station.   
     
     
         18 . The mobile terminal of  claim 17 , wherein the controller includes a CID detector for identifying the non-unique cell identity. 
     
     
         19 . The mobile terminal of  claim 17 , wherein the controller includes a UCID detector for identifying the unique cell identity. 
     
     
         20 . A radio base station controller with an interface for connecting to at least one radio base station and its transceiver and comprising:
 a controller including or being connected to a database that includes a neighbour cell list and including a NCL utility, the controller being arranged for receiving via the transceiver reports from at least one terminal on measured reception quality on other cells than the first cell, including the other cells non-unique cell identities, further arranged for matching the non-unique cell identity with a unique cell identity by retrieving the neighbour cell list, the NCL utility arranged for initiating an instruction being sent to the terminal for identifying and reporting on the unique cell identity of a non-uniquely identified cell if ambiguity arises in the matching, the NCL utility further being arranged for associating the unique cell identity as reported by the terminal with the non-unique cell identity.