I’m not totally clear about what you want to achieve. If you want to minimize TCH occupancy, you must switch-on Half Rate as much as possible. HR will halve the TCH occupancy.
VAMOS is also another feature, but much more controversial. You have to try it out first. 4 calls are allocated onto 1 ts, at best.
Static PDCH cannot be preempted by TCH, but dynamic PDCH can. So whenever TCH traffic gets too high, PDCH will be deallocated. This will not impact the GPRS that much because one user transfer (TBF) is actually using several PDCH (let’s say 4).
What I’m saying is that removing 1 PDCH just means this TBF will be re-allocated onto 4 different PDCH. Those PDCH are not providing as much throughput as the previous ones because other users (TBF) will already be used them.
So our user will experience some throughput reduction (due to pdch sharing), but nothing horrible.
It’s not congestion, see it more like “compacting” all gprs users onto less timeslots.
btw I’m currently doing some GPRS optimization right now, and here are what we’re trying :
100% half rate
increasing the amount of TBF that are packed on a PDCH (call it “increasing the PDCH utilization”)
forcing small volumes TBF to be allocated on only one PDCH (One Slot TBF reservation), the goal here is to allocate all the Routing Area Updates on 1 PDCH. Beautiful results.
Ensure that MCS9 is available, and ensure your Abis is not congested.
Basically, read huawei doc about all their GPRS features, and turn them all on 🙂