Decoding GSM uplink signals


I wonder if any of you guys knows a method to decode uplink GSM signals.
have previoulsy used Airprobe to decode downlink signals, but it does
work with uplink signals. I was using the following scheme:


My approach is to modify gsm-receiver block to adapt it to uplink and to
frequency hopping, and I think that I can solve this issue. But when it
comes to decode the signals…I do not have any idea on how to change
gsmdecode to decode uplink signals. I also wonder if Wireshark is
capable to
do that.

Any idea/advise?