Reference Manual

Packet Data Services

The RBS initiates the setup and synchronization of the GSL, by issuing

PCU frames of type "synchronization". Upon reception of PCU frames

of type "synchronization" by RBS, the GSL is established.

Upon reception of an RF CHANNEL RELEASE from the BSC, Idle

pattern is started to be transmitted to the PCU. The GSL is stopped and

the RBS-PCU connection is released.

Upon reception of a PCU frame of type "synchronization", RBS

associates the downlink FN counter with the Air FN, and returns these

values in the next PCU frame of type "synchronization" to the PCU.

RBS supervises the frame synchronization of the GSL by checking the

PCU frames of type "trafﬁc".

To minimize the downlink delay between the Air interface and the

PCU, RBS continuously monitors, and if necessary adjusts, the

alignment between the Radio Blocks sent on Air Interface and the PCU

Frames received on GSL.

The procedure runs autonomously as long as the GSL is active.

To minimize the uplink delay between the Air interface and the PCU,

RBS measures the difference in time between reception from Air

interface and transmission to PCU, and performs necessary adjustments.

The procedure runs autonomously as long as the GSL is active.

250 (485)

EN/LZT 720 0008 P2A

2001-11-28

Preliminary