METHOD AND APPARATUS FOR FLOW CONTROL AT CELL CHANGE FOR HIGH SPEED DOWNLINK PACKET ACCESS

摘要

A control node (26) of a radio access network participating in a cell change procedure is permitted to begin sending HS-DSCH data frames to a target radio base station (28) even before the control node knows a calculated capacity allocation for the target cell. Such pre-knowledge transmission of HS-DSCH data frames by the control node effectively reduces a control node (e.g., RNC) bitrate transmission gap which otherwise would occur had the control node waited to send the high-speed downlink shared channel (HS-DSCH) data frames after the control node had been informed of the calculated capacity allocation. The control node is permitted to begin sending the HS-DSCH data frames even prior to an activation time (AT), and typically just after a switch time (ST). In one example mode of operation, the pre-knowledge sending of the HS-DSCH data frames to the target radio base station is performed with a presumptive capacity allocation for the target cell. A first type of presumptive capacity allocation is an initial capacity allocation sent from the target radio base station to the control node and configured to evoke transmission of a first HS-DSCH data frame from the control node to the target radio base station. A second type of presumptive capacity allocation is a cell change capacity allocation which is sent to the control node from the target radio base station upon receipt by the target radio base station of the first HS-DSCH data frame evoked by the initial capacity allocation. In an example implementation, the presumptive capacity allocation is related to an (e.g., estimated or approximate) acceptable carrier quality indicator value at a cell border for the cell change.