Last updated: December 3, 2008
This section is only applicable to the lab applications.
The test set allows you to set the value of the Relative Reserved Block Period (RRBP) field of the RLC/MAC block header. This field is defined in 3GPP 04.60 Section 10.4.5.
The RRBP is only valid when the supplementary/poll (S/P) bit is set. This bit gets set when the test set needs to poll the mobile station to determine the quality of the link. When the S/P bit is set, the test set allows the mobile station a limited period of time to respond with either an acknowledgement (ACK) or not acknowledgement (NACK) for the data blocks sent to it. The value of the RRBP field is used by the mobile station to determine the number of the frame it is to use for sending the ACK/NACK response.
The table below illustrates the RRBP values used in the test set and how they map to the bits set for the RRBP field and what this means to the mobile station. The value for N is the frame number of the block received with a valid S/P bit and the corresponding RRBP.
| RRBP field bits | ||
|---|---|---|
|
(N+21 or N+22) mod 2715648 |
||
|
(N+26) mod 2715648 |
For the command to configure the RRBP value in the test set, see CALL:(PDTCH|PDTChannel):RRBPeriod .
If you consider how blocks are organized in a PDCH multiframe (illustrated below with B indicated a block), you can see that with an RRBP of 1 or 2 may include up to 2 Idle or PTCCH frames.
B0B1B2-Idle-B3B4B5-PTCCH-B6B7B8-Idle-B9B10B11-PTCCH
Each block, indicated by B(a number) above, contains 4 frames and each Idle or PTCCH is a single frame, so the total number of frames represented above is 52.
Therefore, consider the following examples: If the RRBP is set to 1 and was sent on B0, the response would come on B4, 17 frames later. However, if the RRBP was sent on B2, the response would have to come in B6, which is 18 frames later because there is an extra IDLE/PTCCH frame in the way.