WCDMA Signaling
R&S
®
CMW-KG4xx/-KM4xx/-KS4xx
62
User Manual 1173.9657.02 ─ 11
pressed, the precondition is reached first, then pattern execution is started. For TPC
setups without precondition the pattern execution starts automatically whenever possi-
ble.
Events:
●
When the signal is switched on:
If the active TPC setup has a precondition, the precondition is reached automati-
cally.
If the active TPC setup has no precondition, pattern execution is started automati-
cally.
●
When the precondition of the active TPC setup is changed while the signal is on:
The new precondition is reached automatically (if it is set to "None", pattern execu-
tion is started).
●
When the active setup is changed while the signal is on:
If the new TPC setup has a precondition, the precondition is reached automatically.
If the new TPC setup has no precondition, pattern execution is started automati-
cally.
Changes of the TX power control settings (including pressing the "Precond." or "Exe-
cute" button) may not be evaluated immediately while reaching a precondition or exe-
cuting a pattern. Instead the changes are evaluated when pattern execution is finished
or the minimum power, maximum power or target power has been reached. While an
"Alternating" or "Continuous Pattern" TPC setup is executed, changes are evaluated at
any time.
2.2.15 Random Access Procedure
Random access procedures are used when establishing the layer 1 communication
between the UE and UTRAN, i.e. when the UE attempts a registration or connection
towards the R&S
CMW.
For this purpose the UE randomly selects access slots and transmits RACH preambles
via the Physical Random Access Channel (PRACH) at increasing power until the Node
B sends an ACK/NACK on the Acquisition Indicator Channel (AICH) or until the maxi-
mum number of preambles within one cycle is exceeded. After receiving an ACK the
UE transmits a message, otherwise the ramping cycle is repeated.
The following figure shows a random access procedure where the UE receives an ACK
after the fourth sent preamble.
General Description
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