bps signalling link usage in 2G, which as discussed has proved to be underestimated in most loaded base stations. This does not necessarily mean anything since 2G and 3G services are different, but taking into account the new ATM layer and its signalling needs in 3G as well as the importance of signalling links to user experience it would definitely be safer to overestimate the signalling capacity. To optimise end user experience about network quality, when it comes to 3G transmission network signalling the guideline of 10% is fine, but to be more safe in the future 15-20% of total link capacity for signalling should be considered. 3G is expected to have high capacities SO from a quality optimisation and configuration management viewpoint allocating a bandwidth equal to one E1/T1/JT1 for each 3G base station should be considered for signalling. This has not been practically possible due to the slow start of the 3G markets and the cost optimisation of networks, but if those difficulties abate then it is definitely something to consider. A way to split signalling capacity between NBAP signalling and AAL signalling links needs to be simulated case by case, with particular service and traffic scenarios. There might also be some differences in the arrangements for signalling between different vendors, SO getting into more detail here might not be generally applicable, even if the direction is clearly to have truly open interfaces in the access networks. Transmission Network Optimisation An important point to note is the fact that the end user does not have insight into signalling capacity problems SO understanding why access to the network cannot be achieved becomes vague if signalling capacity causes the failure. It becomes solely a 'network problem' whereas with coverage problems the end user takes part of the blame. The end user knows that he/she could be in a bad spot for the field but with patience could find a better place after trying once or twice more in a different place, but if transmission signalling fails