Abstract:
A mobile subscriber ( 20 ) initiates a request for packet data services ( 100 ). As the request is processed from network node ( 40 ) to network node ( 50 ), the transmission is checked for errors ( 104 ). For successive failures, exceeding a threshold ( 108 ), an alarm condition along with a cause code corresponding to the particular network node is sent to a network system manager ( 114 ).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention pertains to communication systems and more particularly to a method for performance and fault management for a wireless telecommunications network.  
           [0002]    Today mobile telecommunication networks are complex wireless systems. These mobile telecommunication networks generally provide very little data to a Network Management System for use by performance and fault management applications. This is in stark contrast to the amount of data generated by a telecommunication network node when coordinating call setup, call maintenance and call teardown activities with adjacent nodes.  
           [0003]    Existing fault management systems correlate alarms and failures in software applications based on certain physical conditions of the telecommunication network. The objective of this correlation is to derive the nature and location of a fault or failure so repairs can be completed in an expeditious manner. This type of correlation requires an accurate definition of the relationships between failures and event notifications. Currently these relationships are identified through observation of the operational system and therefore cannot be defined until the operational characteristics of the deployed system are understood. As a result, a newly deployed mobile telecommunication network has poor fault management performance. This means there is further cost and time associated with deploying the new mobile network since many observations and behaviors must be made before the network can be efficiently run and maintained. In addition, the relationships between event notifications and failures are unique to a given physical network. There is no opportunity for cost savings through reuse of event notification/failure relationships.  
           [0004]    Accordingly, what is needed is a robust fault management and system performance methodology available immediately when a mobile telecommunication system is put in service. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0005]    [0005]FIG. 1 is a block diagram of a mobile telecommunication network in accordance with the present invention.  
         [0006]    [0006]FIG. 2 is a flow chart of a method for fault management system performance in accordance with the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0007]    The basis of this invention is the use of the operational call management data that is normally confined to adjacent network nodes for performance and fault management purposes.  
         [0008]    [0008]FIG. 1 is a block diagram of a portion of a mobile telecommunication network  10 . A mobile subscriber  20  is coupled to the URAN (UMTS Radio Access Network)  30 . Mobile subscriber  20  makes a session initiation protocol (SIP) request through URAN  30  to the Serving GPRS Support Node (SGSN)  40 . SGSN  40  in turn transmits a PDP context activation request to the Gateway GPRS Support Node (GGSN)  50 . The GGSN  50  transmits the request through the rest of the call processing network (not shown). All the network nodes such as SGSN  40  and GGSN  50  are coupled to the network manager  60 .  
         [0009]    In the modern telecommunication networks cause codes exist. These cause codes are transmitted between network nodes whenever one node requests an action from a second node and the second node fails to complete the requested action. A cause code indicates a specific reason an action failed to complete. When the number of occurrences of a cause code exceeds a predetermined threshold number of occurrences in any of the system nodes such as SGSN  40  or GGSN  50 , a message identifying the code and the node is transmitted to network manager  60 . By collecting, aggregating and analyzing the cause codes it can be determined where the failure of packet transmission has occurred.  
         [0010]    Referring now to FIG. 2, a flow chart of the method for fault management is shown. Although this example addresses the SIP and PDP protocols, this methodology is applicable to any protocol that incorporates cause codes. The mobile subscriber initiates an SIP access through URAN  30  to SGSN  40 , block  100 . Next, the SGSN transmits a PDP context activation to the GGSN, block  102 . If the SGSN is unable to complete the action of sending a PDP context activation to the GGSN, it sends a notification containing a cause code back to the mobile subscriber. These are routine URAN and SGSN activities in accordance with current protocols. In accordance with this invention, the SGSN increments a count of the number of times that that specific cause code has been sent. If the number of occurrences of that cause code exceeds a predefined threshold, the SGSN notifies the network manager  60 .  
         [0011]    GGSN then determines whether an error occurred in the transmission from SGSN to the GGSN, block  104 . If no error occurred, block  104  transfers control to end this method. There was no error in transmission needing fault analysis.  
         [0012]    If an error did occur, block  104  transfers control to block  106 . If an error occurred, the GGSN sends a message including a cause code to the SGSN in accordance with current protocols. In accordance with this invention, the GGSN increments a count of the number of times that that specific cause code has been sent, block  106 . If the number of occurrences of that cause code exceeds a predefined threshold block  108 , the GGSN notifies the network manager block  114 . If the error count has not exceeded the threshold, block  108  transfers control to block  110  via the NO path.  
         [0013]    The GGSN sends the message containing the cause code to SGSN, block  110 . The SGSN then retries the message transmission transferring control back to block  104  for error checking on subsequent retries.  
         [0014]    Lastly, the network manager  60  will correlate the cause code for the number of times the threshold is exceeded for fault detection and isolation purposes. Suitable reports may be printed or transmitted to the network operations manager to affect repairs.  
         [0015]    Although the preferred embodiment of the invention has been illustrated, and that form described in detail, it will be readily apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the present invention or from the scope of the appended claims.