Spatial and Temporal Fairness in Heterogeneous HSDPA-Enabled UMTS Networks

The system performance of an integrated UMTS network with both High-Speed Downlink Packet Access users and Release '99 QoS users depends on many factors like user location, number of users, interference, multipath propagation profile, and radio resource sharing schemes. Additionally, the user behavior is an important factor; users of Internet best-effort applications tend to follow a volume-based behavior, meaning they stay in the system until the requested data is completely transmitted. In conjunction with the opportunistic transmission scheme implemented in HSDPA, this has implications to the spatial distribution of active users as well as to the time-average user and cell throughput. We investigate the relation between throughput, volume-based user behavior and traffic dynamics with a simulation framework which allows the efficient modeling of large UMTS networks with both HSDPA and Release '99 users. The framework comprises an HSDPA MAC/physical layer abstraction model and takes network aspects like radio resource sharing and other-cell interference into account.