Performance of personal portable radio telephone systems with and without guard channels

Three call handling schemes for a base station which can handle both originating calls (OCs) and prioritized handoff calls (HCs), and which serves these calls under the blocked-call-delayed basis, are presented and compared. Delayed calls are assumed to be stored in a finite storage buffer. One scheme (Scheme I) exclusively allows handoff calls to be stored and to use a fixed number of guard channels. The other two schemes without guard channels (Scheme II-using the last-in/first-out policy for OC´s and Scheme III-using the first-in first-out policy for OC´s) allow both types of calls to be stored, and allow prioritized handoff calls to pushout originating calls if the buffer is full. For these three schemes, the blocking probabilities and delay distributions of both types of calls are numerically obtained, and a boundary for call handling schemes between with and without guard channels is found. From the numerical results, it is shown that Scheme II can be considered a good candidate for a call handling scheme for microcellular systems