Method and arrangement in a telecommunications system

Abstract

The present invention relates to a method and arrangement for triggering a Random Access Channel (RACH) procedure for requesting uplink resources on a random access channel to a radio base station scheduler based on a change in terminal buffer status as compared to a Buffer Status Report BSR stored in said terminal. In a first method step, the status of the present terminal buffer content, i.e. terminal buffer data, is compared with the status of said stored buffer status report BSR. A second method step involves initiating a RACH procedure for indicating a service request to said base station scheduler upon detecting a change of buffer status at said comparison. The service request includes an indicator of the status change as a trigger for said scheduler to assign uplink resources to said terminal.

1 . A method of operating a mobile terminal in a wireless communications system, the mobile terminal comprising a buffer for storing data for transmitting to a base station, the method comprising:
 receiving first data in the buffer;   thereafter, receiving second data in the buffer;   comparing a priority of the first data with a priority of the second data;   determining that the priority of the second data is higher than the priority of the first data, and   initiating a random access channel (RACH) procedure to request uplink resources from a base station scheduler at least partly in response to said determining.   
     
     
         2 . The method of  claim 1  wherein the comparing comprises comparing present buffer status data with previously stored buffer status data. 
     
     
         3 . The method of  claim 2  wherein the previously stored buffer status data comprises a buffer status report (BSR). 
     
     
         4 . The method of  claim 2  wherein the comparing comprises comparing at least one of buffer content priority and radio bearer priority for the respective present buffer status data and the previously stored buffer status data. 
     
     
         5 . The method of  claim 1 , the method further comprising:
 before the second data arrives in the buffer:   initiating an earlier RACH procedure, in response to the first data having arrived in the buffer, by transmitting a RACH preamble to the base station;   receiving a resources grant from the base station scheduler; and   transmitting a buffer status report (BSR) to the base station.   
     
     
         6 . The method of  claim 5 , the method further comprising:
 receiving from the base station an acknowledgement for the BSR.   
     
     
         7 . The method of  claim 1 , the method further comprising:
 determining that a buffer size increase has exceeded a threshold A; and   initiating the random access channel (RACH) procedure at least partly in response to determining that the second data has a higher priority than the first data and determining that the buffer size increase has exceeded a threshold A.   
     
     
         8 . The method of  claim 1 , the method further comprising:
 determining that the time that has passed since a previous RACH initiation exceeds a Threshold B; and   initiating the random access channel (RACH) procedure at least partly in response to determining that the second data has a higher priority than the first data and determining that the time passed since a previous RACH initiation exceeds a Threshold B.   
     
     
         9 . A mobile terminal for use in a wireless communications system, the mobile terminal comprising:
 a processing unit comprising a buffer for storing data for transmitting to a base station, wherein the processing unit is configured to:   receive first data in the buffer;   thereafter, receive second data in the buffer;   compare a priority of the first data with a priority of the second data;   determine whether the priority of the second data is higher than the priority of the first data; and   initiate a random access channel (RACH) procedure to request uplink resources from a base station scheduler at least partly in response to determining that the second data has a higher priority than the first data.   
     
     
         10 . The mobile terminal of  claim 9  wherein the processing unit is configured to compare the priority of the first data with the priority of the second data by comparing present buffer status data with previously stored buffer status data. 
     
     
         11 . The mobile terminal of  claim 10  wherein the previously stored buffer status data comprises a buffer status report (BSR). 
     
     
         12 . The mobile terminal of  claim 10  wherein the processing unit is configured to compare the priority of the first data with the priority of the second data by comparing at least one of buffer content priority and radio bearer priority for the respective present buffer status data and the previously stored buffer status data. 
     
     
         13 . The mobile terminal of  claim 9 , wherein, before the second data arrives in the buffer, the processing unit is configured to:
 initiate an earlier RACH procedure, in response to the first data having arrived in the buffer by transmitting a RACH preamble to the base station;   receive a resources grant from the base station scheduler; and   transmit a BSR to the base station.   
     
     
         14 . The mobile terminal of  claim 9 , wherein the processing unit is further configured to:
 receive from the base station an acknowledgement for the BSR.   
     
     
         15 . The mobile terminal of  claim 9 , wherein the processing unit is configured to:
 determine that a buffer size increase has exceeded a threshold A; and   initiate the random access channel (RACH) procedure at least partly in response to determining that the second data has a higher priority than the first data and determining that the buffer size increase has exceeded a threshold A.   
     
     
         16 . The mobile terminal of  claim 9 , wherein the processing unit is configure to:
 determine that the time passed since a previous RACH initiation exceeds a Threshold B; and   initiate the random access channel (RACH) procedure at least partly in response to determining that the second data has a higher priority than the first data and determining that the time that has passed since a previous RACH initiation exceeds a Threshold B.