Kalman Filter Models for Network Forecasting

Projections of message circuit usage (as measured in hundred call seconds or ccs), from which message circuit requirements (trunks) are developed, and special services* circuit demand are fundamental parts of the Bell System's network planning and provisioning process. An overview of the information flows in this process is shown in Fig. 1; more details are given in Refs. 1 to 4 and in the companion forecasting papers in this issue. Since these projections strongly influence the allocations of several billions of construction dollars annually, it is important that they possess high quality statistical properties. For example, the projections should be unbiased; that is, the forecasts should not be consistently * Special services is a generic term referring to all Bell System services other than ordinary message telephone service. Examples include foreign exchange lines, tie lines, and private lines.