0 References 30/14 This page intentionally left blank Introduction 30/3 30.1 Introduction Such a plan shows the possible routeing arrangements and the transmission loss apportioned to each component of the network Transmission planning is concerned with the transfer of signals e.g. the switches and transmission systems. Individual components across a telecommunications network with the minimum loss of of the network can then be considered separately for design pur- information. Such a transfer will always result in some impairment poses. Providing the loss introduced by that component does not to the transmitted signal due to technical and economic consider- exceed the transmission plan limit allocated, the component de- ations. Distortionless transmission is not generally technically signer need not know the exact network structure. The transmission possible and near-distortionless transmission may not be economi- plan can therefore be considered as the budget, in this case, for cally viable. The role of the transmission planner is to work within transmission loss. the technical and economic constraints to control the impairments Similar budgets can be drawn up for the other essential trans- introduced by the network. The objective is to ensure that the end to mission parameters. In all cases these budgets provide the informa- end performance meets the customer requirements for the services tion on the relevant performance limit for the individual network in question. component and can be used by the component specifier or designer. The key steps in the process are: 1. Understanding the customer service requirement. Typical service groups 2. Relating these requirements to the relevant end to end trans- mission impairments. A transmission parameter requires an apportionment or budget 3. Understanding the factors determining end to end performance. where it affects the end to end performance of the service in 4. Developing a transmission plan. question, hence the parameters need to be service based. The rela- tion