Failures in a message exchange, during a procedure for determining the
location of a mobile station, are alleviated by providing a retry
mechanism. Upon receipt of a particular failure message, such as the SMS
Cause Code 33, rather than abort the location operation, the node
receiving the failure message retransmits its last previous message. In
an Assisted GPS (AGPS) example, essentially, whenever the Position
Determining Entity (PDE) 25 receives an SMS Cause Code 33 from the mobile
switching center (MSC) 15, it will resend the last previous Invoke
message, without delay or alteration. This will give MSC 15 another
chance to deliver the message to the mobile station 5 and ideally
continue the message flow until the mobile station has been successfully
located. The PDE 25 may retry a particular Invoke message one or multiple
times. The receipt of other SMSCauseCode values may still cause the
message exchange to abort.