tion. 3.4.5.2 Radio Environment Survey The radio environment survey performs quality estimates and measurements on radio channels from current and surrounding cells; as in [6] these functions, located in the UE and UTRANS, include: received signal strengths (current and surrounding cells); estimated bit error ratios, (current and surrounding cells); estimation of propagation environments (e.g. high-speed, low-speed, satellite, etc.); transmission range (e.g. through timing information); Doppler shift; synchronization status; received interference level; total DL transmission power per cell. 3.4.5.3 Macro-diversity Control - FDD In FDD, macro-diversity control manages duplication/replication of information streams to receive/transmit the same information through multiple physical channels (or different cells) from/towards a single mobile terminal. This function also controls combining of information streams generated by a single source (diversity link), but conveyed via several parallel physical channels (diversity sub-links). Macro-diversity control interacts with channel coding control to reduce bit error ratio when combining different information streams. Depending on the physical network configuration, combining/splitting may occur at the SRNC, DRNC or Node B level. 3.4.5.4 TDD - Dynamic Channel Allocation (DCA) The TDD mode uses fast or slow DCA. Fast DCA implies assigning resources to the radio bearers in relation to the admission control. Slow DCA implies assigning radio The UMTS Development Platform resources, including time slots, to different TDD cells depending on the varying cell load. 3.4.5.5 Allocation/De-allocation and Control of Radio Bearers The allocation/de-allocation function located in the CRNC and SRNC, translates the connection element set up requests into physical radio channel allocation according to the QoS of the radio access bearer. It gets activated, e.g. during a call when user service request varies or during macro-diversity. Radio bearer control located both in the UE and in the RNC