In search of lost capacity: non-effective load in UMTS radio interface (uplink)

In this paper we analyze the problem of non-effective load, or wasted capacity, in the UMTS uplink (UL) interface. The non-effective load is generated by users in outage (whose signal quality is below the target value), who have not been dropped yet. This is because of the existence of a timer which prevents dropping a user in the case of temporary quality degradation. We check how the wasted capacity depends on the dropping timer, discontinuous transmission (DTX), mobility in an environment of shadowed losses and users´ arrival process. Finally, we propose to use the wasted capacity as a load indicator. We also show that the non-effective load increases the cost of admitting a new effective user to the network above generally assumed estimations.