Avoiding unlimited number of unsuccessful location update or packet data connection establishment attempts

摘要

The application relates to the procedures Routing Area Update RAU in UTRAN and Tracking Area Update TAU in LTE. Furthermore, it relates to PDP context procedure in UTRAN as well as PDN connection procedure in LTE. In the current RAU procedure, a SGSN, which fails to update the Routing Area, e.g. because it receives the DNS return error, sends a RAU Reject with the cause code CC#17 indicating a network failure back to the user equipment (114b). The cause code CC#17 in the RAU Reject causes the user equipment to send a new RAU Request. Thus, the user equipment is stuck in a loop of sending a RAU Request and receiving a RAU Reject. This problem is solved by the present application in that SGSN keeps track of the number of rejections when doing RAU. When the number of rejections is above a certain threshold, the SGSN will send a RAU Reject with cause code CC#10 to the user equipment (115b), whereby the cause code CC#10 indicates implicit detach of the user equipment. In other words, the cause code is changed from CC#17 to CC#10 and in order to avoid further looping. The same principle is applied to TAU in LTE as well as to PDP procedures in UTRAN and LTE.

主权项

1. A method in a first network node for handling a user equipment in a communication network, wherein the first network node is connected to the user equipment, the method comprising:
receiving a request message from the user equipment, which request message is a Routing Area Update, RAU, message or a Tracking Area Update, TAU, message, which RAU or TAU message is a request for an update related to an area to which the user equipment has moved, or which request message is an activate Packet Data Protocol, PDP, context request message or an activate Packet Data Network, PDN, connection request message, which PDP context request or activate PDN connection request message is a request for transmitting data in the communication network; obtaining information about rejection of the request message; increasing a parameter indicating a number of rejections associated with the user equipment based on the obtained information; and transmitting, to the user equipment, instructions to detach the user equipment from the first network node when the parameter is above a threshold, wherein the instruction to detach the user equipment is comprised in a RAU reject message or a TAU reject message when the received request message is a PDP context request or activate PDN connection request message; and wherein the instructions to detach the user equipment is comprised in a detach request message when the received request message is an activate PDP context request or activate PDN connection request message; and wherein the first network node is a Serving General packet radio service Support Node, SGSN, or a Mobility Management Entity, MME, or a combined SGSN and MME.