Extended Queueing of Handover (EQH) Scheme

Extended Queueing of Handover (EQH) Scheme

In a handover process, a UT with unfulfilled handover request will have its call terminated once it leaves the present cell i.e. when the signal strength of the present beam drops below an acceptable level. Under the proposed Extended Queueing of Handover (EQH) scheme [5], the policies of queueing and early channel reservation also apply to handover calls. In addition to them, the queueing process of an initially unfulfilled handover is allowed to be continued in the destination cell and thus lasts longer, promising a higher chance of obtaining a free communication channel. In this case, since the UT has left the present cell and has not reserved a channel from the destination cell,
its call has to be discontinued until either a free channel is available on which the call can be resumed on,or until the tolerable suspension period is over which the call has to be permanently terminated,whichever comes first. Although this suspended call is prioritised over new call in getting a channel, it does not significantly affect the blocking rate of new call because the probability that a call get suspended is very small. From the viewpoints of the two involved communicating parties in an initially unsuccessful handover call,
the discontinuity can be notified through a special tone / message. In terms of quality of service (QoS), a suspended call that eventually gets terminated is better than a disruptive and uninformed drop call. On the other hand, if the call is able to be resumed upon the availability of an idle channel, the short term discontinuity makes it worth than having the call terminated and followed by setting up a new call again, which is harder because new call is less privileged. Hence regardless of the outcome EQH scheme promises a higher QoS.