New caching-based location management scheme in personal communication systems

We propose a new location management strategy that is based on a centralized database architecture with the home location register/visitor location register (HLR/VLR) concept. Our basic idea is to reduce the cost of call delivery using location information cached at the MSC/VLR. Other proposed caching-based schemes may have cached invalid location information as the MT moves into a new registration area. However, our scheme cannot cache invalid location information as announcing the location of the MT to MSC/VLR or invalidating the location information by the MSC/VLR. That is, with cached location information, a miss cannot occur. Therefore, the call setup delay for our proposed scheme is always shorter than, or equal to that of the current method. Our scheme minimizes the total signaling cost of location management by reducing the cost of call delivery more than the increased cost of the location update. The analysis of the proposed scheme, using simulation, shows that the new scheme outperforms or equals the current methods in cost and has a much better performance at high CMR (call to mobility ratio)