An adaptive measured-based preassignment scheme withconnection-level QoS support for mobile networks

摘要

This paper presents a new adaptive bandwidth allocation scheme tonprevent handoff failure in wireless cellular networks, known as thenmeasurement-based preassignment (MPr) technique. This technique isnparticularly useful in micro/pico cellular networks which offersnquality-of-service (QoS) guarantee against call dropping. The proposednMPr scheme distinguishes itself from the well-known guarded channel (GC)nbased schemes in that it allows the handoff calls to utilize anprereserved channel pool before competing for the shared channels withnnew call arrivals. The key advantage of the proposed MPr scheme is thatnit enables easy derivation of the number of channels that needs to benreserved for handoff based on a predetermined handoff droppingnprobability, without the need for solving the often complex Markov chainnrequired in GC schemes, thus, making the proposed MPr scheme simple andnefficient for implementation. This is essential in handling multiplentraffic types with potentially different QoS requirements. In addition,nthe MPr scheme is adaptive in that it can dynamically adjust the numbernof reserved channels for the handoff according to the periodicalnmeasurement of the traffic status within a local cell, thus completelyneliminating the signaling overhead for status information exchange amongncells mandated in most existing channel allocation schemes. Numericalnresults and comparisons are given to illustrate the tradeoff