?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F69%2F&rft.title=Frequency+reassignment+in+cellular+phone+networks&rft.creator=Billingham%2C+John&rft.creator=Leese%2C+Robert&rft.creator=Rajaniemi%2C+Hannu&rft.subject=Information+and+communication+technology&rft.description=In+cellular+communications+networks%2C+cells+use+beacon+frequencies+to+ensure+the+smooth+operation+of+the+network%2C+for+example+in+handling+call+handovers+from+one+cell+to+another.+These+frequencies+are+assigned+according+to+a+frequency++plan%2C+which+is+updated+from+time+to+time%2C+in+response+to+evolving+network+requirements.+The+migration+from+one+frequency+plan+to+a+new+one+proceeds+in+stages%2C+governed+by+the+network's+base+station+controllers.+Existing+methods+result+in+periods+of+reduced+network+availability+or+performance+during+the+reassgnment+process.%0A%0AThe+problem+posed+to+the+Study+Group+was+to+develop+a+dynamic+reassignment+algorithm+for+implementing+a+new+frequency+plan+so+that+there+is+little+or+no+disruption+of+the+network's+performance+during+the+transition.+This+problem+was++naturally+formulated+in+terms+of+graph+colouring+and+an+effective+algorithm+was+developed+based+on+a+straightforward+approach+of+search+and+random+colouring.&rft.date=2006&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F69%2F1%2FMotorola-report.pdf&rft.identifier=++Billingham%2C+John+and+Leese%2C+Robert+and+Rajaniemi%2C+Hannu++(2006)+Frequency+reassignment+in+cellular+phone+networks.++%5BStudy+Group+Report%5D+++++