Uplink congestion detection and control between nodes in a radio access network

Abstract

Congestion in a radio access network (RAN) associated with transporting uplink information originating from one or more mobile terminals is detected. That detected RAN congestion is reduced using any suitable technique (several examples are described) and may be implemented in one or more nodes in the RAN. One advantageous (but non-limiting) application is to a RAN that supports high speed uplink packet access (HSUPA) and/or one or more enhanced uplink dedicated channels (E-DCHs).

What is claimed is: 
     
         1 . A method for managing congestion on an uplink from a base station to a radio network controller in a radio access network (RAN), comprising:
 detecting, at the radio network controller, congestion over an interface between the base station and the radio network controller, said congestion being caused by transporting uplink information from the base station to the radio network controller, the uplink information being received from a plurality of mobile terminals, and said detecting of congestion comprising detection of frame loss or frame delay; and   in dependence on detecting at the radio network controller said congestion on the uplink from the base station to the radio network controller, sending a congestion message from the radio network controller to the base station indicating that the base station should reduce a bit rate to control the congestion.   
     
     
         2 . A method according to  claim 1 , wherein the congestion message indicates that, in dependence on receiving the congestion message at the base station, the base station should send control data to the mobile terminals to reduce a bit rate of the uplink information. 
     
     
         3 . The method in  claim 2 , wherein the control data relates to reducing a bit rate parameter associated with a bit rate at which the uplink information is transported over the interface between the base station and the radio network controller. 
     
     
         4 . The method in  claim 3 , wherein the uplink information is communicated to the RAN over a radio interface using uplink data flows, and wherein the bit rate parameter is reduced by reducing a bit rate of one or more uplink data flows. 
     
     
         5 . The method in  claim 3 , wherein the bit rate parameter is reduced based on an absolute bit rate parameter value or on a relative bit rate parameter value. 
     
     
         6 . The method in  claim 5 , wherein the absolute bit rate parameter value corresponds to a maximum bit rate or transmission power and the relative bit rate parameter value corresponds to a percentage or fraction of a current bit rate or transmission power. 
     
     
         7 . The method in  claim 3 , wherein the bit rate parameter is reduced by sending control information in a control plane or in a user data plane. 
     
     
         8 . The method in  claim 3 , wherein the bit rate parameter is reduced using scheduling grants or credits for uplink mobile terminal communications. 
     
     
         9 . The method in  claim 3 , wherein the bit rate parameter is reduced by dropping one or more frames of one or more uplink mobile terminal communications. 
     
     
         10 . The method in  claim 3 , wherein the bit rate parameter is reduced by releasing one or more diversity handover radio links. 
     
     
         11 . The method in  claim 1 , wherein a first amount of bandwidth is allocated to uplink dedicated channels and a second amount of bandwidth is allocated to enhanced uplink dedicated channels, and wherein the radio network controller sends a message to the radio base station to reduce the second amount of bandwidth when uplink congestion is detected in the RAN. 
     
     
         12 . Apparatus for managing congestion on an uplink from a base station to a radio network controller in a radio access network (RAN), comprising:
 a congestion detector configured to detect congestion over an interface between a base station and a radio network controller, said congestion being caused by transporting uplink information from the base station to the radio network controller, the uplink information being received from a plurality of mobile terminals, said detecting of congestion comprising detection of frame loss or frame delay; and   a congestion controller configured to reduce the detected congestion on the uplink form the base station to the radio network controller by sending a congestion message from the radio network controller to the base station indicating that the base station should send control data to the mobile terminals to reduce the rate of uplink of information.   
     
     
         13 . The apparatus in  claim 12 , wherein the congestion controller is configured to reduce a parameter associated with a bit rate at which uplink mobile terminal information is transported through the RAN. 
     
     
         14 . The apparatus in  claim 12 , wherein the congestion controller is configured to cause the base station to reduce a bit rate of one or more uplink mobile terminal transmissions. 
     
     
         15 . The apparatus in  claim 12 , wherein the congestion controller is configured to send a signal to the radio base station to restrict scheduling of one or more uplink transmission grants or credits. 
     
     
         16 . The apparatus in  claim 12 , wherein a first amount of bandwidth allocated to uplink dedicated channels and a second amount of bandwidth is allocated to enhanced uplink dedicated channels, and wherein the radio network controller is configured to send a message to the radio base station to reduce the second amount of bandwidth when uplink congestion is detected in the RAN. 
     
     
         17 . Apparatus for managing congestion on an uplink from a base station to a radio network controller in a radio access network (RAN), comprising:
 a scheduler configured to schedule uplink transmissions from a plurality of mobile terminals, and   a congestion controller, coupled to the scheduler, configured to receive a congestion message from the radio network controller, and in response, to reduce congestion over an interface between the base station and the radio network controller, said congestion being caused by transporting uplink information from the base station to the radio network controller, the uplink information being received from the mobile terminals, and said detecting of congestion comprising detection of frame loss or frame delay, wherein reducing congestion comprises, in dependence on receiving the congestion message, causing the scheduler to send control data to the mobile terminals to reduce the rate of uplink information.   
     
     
         18 . The apparatus in  claim 17 , wherein the congestion controller is configured to instruct the scheduler, dependent on the congestion controller receiving the congestion message, to restrict uplink transmission grants or credits provided to the mobile terminals. 
     
     
         19 . The apparatus in  claim 17 , wherein the congestion controller is configured to drop one or more frames associated with one or more uplink mobile terminal communications, dependent on the congestion controller receiving the congestion message. 
     
     
         20 . The apparatus in  claim 17 , wherein the congestion controller is configured to reduce a bit rate or power associated with one or more uplink mobile terminal communications using negative acknowledgement messages, dependent on the congestion controller receiving the congestion message.