A model for estimating installed first costs of NGPN translation in PCS systems

Future wired networks with an ATM backbone will need to support PCS and wireless subscriber services. One of the key functions required to support PCS and wireless subscribers with non-geographic phone numbers (NGPN) will be the ability to efficiently identify which home location register (HLR) database serves the subscriber. (Note that the same functionality is also needed to serve subscribers with portable phone numbers.) In a previous paper we have presented a scheme for NGPN translation based upon distributed, dynamic hashing. The scheme uses a hash function in the visitor location registers (VLR) and a set of distributed translation servers (TS) which store the NGPN-to-HLR mapping. We develop a simplified model for estimating the capital investment cost of deploying the NGPN translation scheme we have proposed. The model focuses on the incremental cost of providing NGPN service by estimating the installed first cost (IFC) of deploying TSs. The cost model assumes that PCS subscribers adopt NGPNs following the classic Fisher-Pry model of technological adoption, and takes into account user mobility, caching, the projected growth in the performance of computing servers, and projected decline in their cost, as well as inflation, the time value of money, and population growth. The cost model is fully parameterized, allowing network planners to substitute appropriate values to evaluate “what-if” scenarios. We illustrate its use for an example scenario. We also point out that the cost model itself is quite generic and may be applicable to other network costing and operations planning tasks