The Research On Flow Control In Upstream Direction For Iub Interface In HSUPA

HSUPA was included by in Release 6 standard published by 3GPP, and many new techniques were introduced to WCDMA system, such as a new transport channel E-DCH on which the coding channel whose SF is 2 is supported, a packet schedule strategy based on NodeB and a physical layer retransmission strategy HARQ. In this way, data services with send rate as high as 5.76Mbps can be supported in the uplink direction. Thus, the methods to control the data flow at Iub interface become an key issue.A flow control algorithm based on the detection of cache occupancy rate is generally used today. Though the algorithm is easy to implement, it also has some disadvantages of its own.In this paper, a new flow control algorithm based on the detection of cache occupancy rate and congestion was proposed to resolve the disadvantages of the flow control algorithm above. With a mechanism to detect the congestion of the transport network between NodeB and RNC, the new algorithm can work effectively without the disadvantages mentioned above. The simulation results show that the flow control algorithm based on the detection of cache occupancy rate and congestion performs better in packet loss rate and adjustment of data send rate.