Supporting multiple priority calls, we propose the queueing strategies which efficiently manage the queue to reduce the blocking probability with multiclass calls in multiservice personal communications services (MPCS). The two queueing schemes are proposed and are shown the analytic model with (n+1) class calls. Numerical results demonstrate that the two proposed schemes show the improved performance compared to the previous scheme with two types of traffic in terms of the blocking probability. The proposed schemes are flexibly adaptable to MPCS.
Technological advances and rapid development of handheld wireless terminals have facilitated the rapid growth of wireless communications and mobile computing. Taking ergonomic and economic factors into account and considering the new trend in the telecommunications industry to provide ubiquitous information access, the population of many users will continue to grow at a tremendous rate. Another important developing phenomenon is the shift of many applications to multimedia platforms in order to present information more effectively.
The tremendous growth of the wireless/mobile user population, coupled with the bandwidth requirements of multimedia applications, requires an efficient use of the scarce radio spectrum allocated to wireless/mobile communications.
It has been anticipated that demands for multiple types of service from low-bandwidth applications such as voice to high-bandwidth applications such as data, image, and video will grow for future mobile personal communications. For delivering the desired levels of quality of service (QoS) in multiservice personal communications services (MPCS) to multiple type of mobile users, an improved channel allocation mechanism is required. It is to obtain a high admitted traffic and to reduce blocking probability while guaranteeing the protection of calls in restricted channels. The channel allocation scheme has been introduced such as fixed channel allocation (FCA), dynamic channel allocation (DCA), hybrid channel allocation (HCA), distribute channel allocation (DCA), borrowing channel allocation (BCA), and adaptive channel allocation (ACA) [16] and [17]. For reducing blocking probability of call, those schemes make use of queueing in personal communications services (PCS).
We classify calls in PCS as voice call and data call: new voice call, new data call, hand-off voice call, and hand-off data call. Intuitively, when channels are busy, the blocking probability of the hand-off data call can be reduced by waiting only the hand-off data call in the queue. The blocking probability of voice call can be also reduced by giving priority to voice call in the queue environment [1], [3], [4], [7], [10], [11], [12] and [13].
Another priority control method is the measured based priority scheme (MBPS). It is the scheme in which the hand-off call requests which can not be served are queued and served according to a signal power level based strategy [14]. MBPS always shows the better performance than FIFO scheme does.
However, the previous schemes consider only two class calls and have limits in reducing the blocking probability of multiple priority calls by allocating channels efficiently in MPCS. An efficient queueing management with priority methods for multiclass calls can reduce the blocking probability of calls in restricted channels in a cell.
In this paper, we consider the queueing strategies for multiple priority calls in MPCS and propose the two queueing schemes. As main performance measures, the blocking probability and the mean waiting time of multiclass calls are considered.
The organization of the paper is as follows. Section 2 describes the previous queueing scheme with two types of traffic. Section 3 describes the two proposed queueing schemes of (n+1) class calls, which show the blocking probability and the mean waiting time of priority calls as main performance measures. In Section 4, the analytic results of two schemes are verified by performing the simulation and compared to the previous scheme with two types of traffic (voice calls and data calls). Additionally, we compare the two proposed schemes of each other with four class calls. Finally, we conclude this paper in Section 5.
We propose the queueing strategies with multiple priority calls to reduce the block of channel allocation in multiservice personal communications services. In the two proposed schemes, we present the efficient queueing schemes and show the analytic model of (n+1) class calls. Compared to the previous scheme with two class calls, the proposed scheme I have the same performance to that of previous scheme in terms of blocking probability. However, the proposed scheme II shows an improved performance. In the two proposed schemes, scheme II has a better performance than scheme I with respect to the blocking probabilities with four class calls, where scheme I has better results than scheme II in terms of the mean waiting time. The proposed schemes can be flexibly applied to multiservice personal communications services.
