ed zone means that a grey area is entered where the input parameters are indeed in an unauthorized zone but where the results of the algorithm might still be on the safe side compared to using the most accurate Transmission Network Planning and Optimisation Table 3.15 Example of varying loss and delay parameter Loss probability Delay [ms] Bandwidth need bps 772673 1110068 possible admission control algorithm. This is where the optimisation risk is on the engineer who is actually performing the task. To highlight the differences in tweaking the parameters, Table 3.15 gives an example of the same traffic mix in the same base station configuration with different loss and delay parameters settings for an AAL connection admission algorithm used some time ago. The graph in Figure 3.81 illustrates how delay (cell buffers), bandwidth (offered load) and loss (CLR) are coupled in general. Transmission Quality Loss Transmission quality loss is the third possible cause of quality problems in transmission accessibility. The network might have the signalling capacity and it might have the needed capacity for user traffic channels, but still the access might fail due to either occasional corruption of information in connection setup messaging or to some more frequent corruption cause of information in connection setup messaging. If it is only some occasional corruption caused by, for example, a voltage surge then there is not much to do. No system is bulletproof to all occasional incidents, SO those cases are just the statistical failures that do not pay off the effort to be optimised. However, if it is due to repeated corruption that cannot be explained then it makes sense to find out what is the root cause of that. The possible causes are, for example, poor copper cable quality, bad connectors, hardware problems microwave transmission link problems and extra-equipment problems like heat, condensation, ice, etc. The list can get long. It is a good idea to start excluding possible causes from extra-equipment candidates, since t