Why do you think the SACCH is congested ? LBS doesn’t use SACCH, does it ?
Does it use SACCH to transmit a kind of SMS ?
SACCH has a static “throughput”, which is reserved. It cannot be shared, cannot be preempted, cannot be congested. Every call has its own SACCH capacity. It’s static.
LBS over SACCH is probably mapped on the same SAPI as “SMS over SACCH”, which has the lowest priority when the ABIS RSL is congested.
So yeah, definitely, look into your RSL.
SDCCH blocked –> YES, it is due to the LBS activity.
If RSL congestion –> depending on vendor strategy, some services will be delayed or even blocked. Typically, SMS are probably the first messages to be discarded, to avoid getting in a hard RSL congestion.