User`s guide

376 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
Multiple PRACH Overview
Figure 15-20 Timing Setup Display
However a single UE retransmission of its PRACH cannot overlap its previous PRACH
transmission within the same 80 ms period. For example, if UE1’s PRACH is 11.5 access slots
long and its first PRACH transmission starts in access slot zero, then the second PRACH
transmission for UE 1 must start, at a minimum, in access slot 12. If it was configured to
begin in access slot 11, the second transmission would not occur because slot 11 is partially
occupied by the first PRACH transmission. But different UEs can transmit in access slots
occupied by other UEs. Figure 15-21 illustrates an example of when a PRACH retransmission
for the same UE is ignored. It also demonstrates how PRACHs can occupy the same access
slots when they are transmitted by different UEs.
Eight
Eight Assignable Access Slots
Per UE within the 80 ms Period
Clears all Access
where an Item is
UEs
Slots from the Row
Highlighted
Preamble Signatures
The First Position is Assigned
Access Slot Zero as the Factory Default