Channel assignment for initial and handoff calls to improve the call-completion probability

The paper focuses on how to assign channels for initial and handoff calls. Previous schemes give priority to handoff calls by queuing handoff calls, reserving some channels for handoff calls, or subrating existing calls for handoff calls. We queue both initial and handoff calls. We take this idea from derivations of the optimal value for an approximation to the call-completion probability. Our goal is to have higher call-completion probability and still keep forced-termination probability low. We propose four schemes: SFTT (single-queue, FIFO, timeout, average timeout), SPTT (single-queue, priority, timeout, average timeout), DFTS (dual-queues, FIFO, timeout, statistical TDM), and DPTS (dual-queues, priority, timeout, statistical TDM). The four schemes, along with the NPS and FIFO schemes, were simulated and compared. For the SFTT scheme, we also simulated different average timeouts for initial calls. All four proposed schemes have better call-completion probabilities than the NPS and FIFO schemes. Call-completion probabilities can be improved by implementing a priority scheme which serves the waiting call with the least remaining time first. The implementation of statistical multiplexing also has the effect of increasing call-completion probability when the average new-call arrival rates are high. However, both the priority scheme and statistical multiplexing may increase forced-termination probability.