 tree allocated for a certain user in the density. Although noise rise as such is not of major in- downlink remains constant throughout the packet call terest, it has a close relation to coverage and uplink load. A (unless the parameters are reconfigured). Furthermore, as large noise rise would result in loss of coverage of some downlink transport format selection is located in the channels - a terminal may not have sufficient transmission RNC, it is not aware of the instantaneous power con- power available to reach the required Eb/No at the base sumption in the NodeB. The RRC must therefore use station. Therefore, the radio resource control in the RNC a certain margin when admitting users into the system to must keep the noise rise within certain limits. The NodeB ensure that sufficient transmission power is available for provides uplink measurements which enables the RNC to any transport format the MAC may select. Similarly, in estimate the uplink load. the uplink, the RRC can only observe the average uplink Provided there are sufficient resources in both uplink interference and must therefore have sufficient margins and downlink, the RNC admits the UE into the cell and to handle the case of all UEs suddenly selecting the configures a dedicated (physical) channel in each di- transport format corresponding to the highest data rate rection. Several parameters are configured, one of them and therefore the highest transmission power. In other being the set of transport formats the MAC layer in the words, the amount of resources reserved for a user is fairly UE and the RNC are allowed to select from for uplink static during the period of the packet call. This is suitable and downlink transmissions, respectively. Hence, the for services with a relatively constant data rate, for ex- RNC reserves resources corresponding to the highest ample voice services or interactive video transmission, data rate the UE may transmit with during the call. In the but, significant enhancements are possible for packet-data downlink, a f