ISSN : 1796-2021
Volume : 4    Issue : 2    Date : March 2009

Effect of TNL Flow Control Schemes for the HSDPA Network Performance
Thushara Weerawardane, Andreas Timm-Giel, Carmelita Görg, Gennaro C. Malafronte, and Stephan Hauth
Page(s): 78-88
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HSDPA (High Speed Downlink Packet Access) is an extension of the current UMTS (Universal Mobile
Telecommunications System) technology with the objective to increase the data rate and to reduce the
latency in the downlink. The main focus of this investigation is to optimise the Iub interface to provide the
best end user performance at minimum cost for UMTS HSDPA network. An adaptive credit-based flow
control mechanism for UTRAN transport has been developed, tested and validated in the HSDPA simulation
model. In this paper, the HSDPA performance with the new adaptive credit-based flow control mechanism is
compared with the generic ON/OFF flow control mechanism. The results confirm that the adaptive
creditbased flow control mechanism can significantly improve the performance and therefore reduce the
required bandwidth at the Iub interface meeting a specified performance: The better bandwidth utilisation
and improved statistical multiplexing is achieved by reducing the burstiness of the traffic over the Iub
interface. Finally, a recommendation for the required bandwidth at the Iub interface is given for bursty HSDPA

Index Terms
HSDPA, RNC, Node-B, Flow Control