B.5 Example
3GPP45.008GSM/EDGE Radio subsystem link controlTS
Figure B.1 illustrates an example of the uplink power control function.
In packet idle mode or MAC-Idle state, the MS measures the C value on each monitored PPCH block. Meanwhile, the BSS measures the interference of the candidate PDCHs in order to have CH values ready for the first transfer period. This is transferred to the MS in the Packet Uplink Assignment.
In packet transfer mode or MAC-Shared state, the MS measures the C value on the BCCH carrier and updates its output power. The BSS updates the MS specific CH values and transfer them to the MS when needed, i.e. when the interference level has changed.
Figure B.1: Traffic example of uplink power control
Figure B.2 illustrates an example of the downlink power control function.
In packet idle mode or MAC-Idle state, the MS measures the C value on each monitored PPCH block.
In packet transfer mode or MAC-Shared state, the MS measures the C value on the BCCH carrier and the CH values on all channels on the same carrier as the assigned PDCH. These values are transferred to the BTS in the Packet Downlink Ack/Nack messages. The BSS then updates the output power.
The BTS may use the maximum power for the first transfer period and set the polling for Ack/Nack as soon as possible to get the values measured in packet idle mode or MAC-Idle state.
Figure B.2: Traffic example of downlink power control