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Reply To: Suspend in DL_TBF_Release_Cause in ALU

#62059
Pix
Guest

Paul,

Here goes the big answers 🙂 let me know if that’s clear enough…

1)
When the TBF is suspended, it means that it is actually “released”. In other words, the user has ONLY a TCH timeslot, and no PDCH at all.

At the end of voice call, a new TBF will be established (= resume).
During the voice call, the user cannot browse the internet anymore.

2) yes, you can set max pdch as high as you want, because the BSC will anyway allocate the “real” number of PDCH depending on the TCH usage. Even if you put max pdch very high, the “voice capacity” of the cell will not get congested.

3)
well, this question is a little obscure. MIN PDCH are statically allocated. On each PDCH, there could be up to “MAX_TBF_PER_SPDCH” subscribers (users are multiplexed onto the same timeslot)
Each user can use up to “MAX_PDCH_PER_TBF” consecutive timeslots.
The MFS will allocate as many PDCH as possible before “multiplexing” users on the same PDCH. It can allocate up to max pdch timeslots.
when the voice usage gets high in the cell, the previously allocated PDCH are de-allocated. Only the last “max pdch high load” timeslots will remain allocated to the subscribers.
Users that were located on the preempted PDCH are not dropped : the MFS attempts to reallocate their TBF on the other PDCH. The throughput will decrease, but the connection remains available.

Note : only the MS that are “DTM capable” can support both PDCH and TCH at the same time. This is a B10 feature. Most MS are not DTM capable.

pix