very relaxed delay requirements will also fortunately, the upper limit of the data rate demand and be there. Thus, not only high data rate services with a low- the lower limit of the delay requirement are difficult to latency requirement, but also low data rate best effort provide in a cost-efficient manner. The designers of the services will be provided. Furthermore, not only the data mobile-communication systems need to stop at a rea- rate and delay are important to understand when talking sonable level, a level that the technology available at the about a service's need from a mobile-communication time of standardization can provide. system, but also the setup time is very important. For example, a service can be totally useless if it takes too long to start it (for example, making a phone call, downloading 4.2.1.3 Cost and performance a web page). Thus the mobile-communication systems of the future, including the evolution of 3G mobile commu- There is another important driving factor for future nication, need to be able to deliver short call setup times, mobile-communication systems and that is the cost of low latency and a wide range of data rates. the service provisioning. The technology advancement that enables new services can also be utilized to provide better mobile-communication systems using more ad- 4.2.1.2.4 Key design services vanced technical features. Here IP technology is not only Since it is impossible to know what services will be a key enabler to allow for new services to pop up, but also popular and since service possibilities and offers will a way of reducing cost of new services. The reason is that differ with time and possibly also with country, the IP as a bearer of new services can be used to introduce future mobile-communication systems will need to be new services as they come, not requiring an extensive 3 The faster the data are delivered the better. Expert Counter Strike players look for game servers with a ping time of less than 50 ms. 4 In 3G systems the end-to-end delay requireme