Wei-Yeh Chen

Performance comparisons of dynamic resource allocation with/without channel de-allocationin GSM/GPRS networks

In this letter, we analyzed and compared the performance of dynamic resource allocation with/without channel de-allocation in GSM/GPRS networks. It is quite known that dynamic resource allocation allows communication systems to utilize their resources more efficiently than the traditional fixed allocation schemes. In GPRS, multiple channels may be allocated to a user to increase the transmission rate. In the case when there are no free channels in the system, some of these channels may be de-allocated to serve higher priority calls. The results show that with channel de-allocation mechanism, the voice blocking probability can be greatly reduced, especially at high GPRS traffic load. Besides, the scheme with channel de-allocation mechanism can achieve higher channel utilization.

Performance analysis of radio resource allocation in GSM/GPRS networks

General packet radio service (GPRS) is a packet switched access mode for GSM system to efficiently utilize the radio resources. In this paper, we analyzed the performance of radio resource allocation in GSM/GPRS networks. To guarantee the QoS of voice service not being affected by the introduction of GPRS, preemptive priority is applied for voice calls to preempt GPRS data packets. Three cases of radio resource allocation are considered: no-buffer; buffer-only-for-preempted-GPRS-packets; and buffer-for-GPRS-packets. The results show that employing a buffer for GPRS packets can greatly reduce its blocking probability even under the condition of voice preemption. For real-time data applications, the mechanism of buffer-only-for-preempted-GPRS-packets is suitable since the queueing delay is relatively small.

The study of handoff prediction schemes for resource reservation in mobile multimedia wireless networks

In this paper, the mobility-dependent predictive resource reservation (MDPRR) scheme is proposed to provide flexible usage of scarce resource in mobile multimedia wireless networks. An admission control scheme is also considered to further guarantee the QoS of real-time traffic. The area of a cell is divided into non-handoff, pre-handoff, and handoff zones so that bandwidth is reserved in the target/sub-target cell as mobile stations move into the pre-handoff zone and leave the serving base station. The amount of bandwidth to be reserved is dynamically adjusted according to the location, the instantaneous variation of velocity and direction of mobile stations. Two scenarios of the MDPRR scheme are compared by considering the velocity threshold in the calculation of the weight of direction. A number of designs are investigated to further enhance the performance of the proposed scheme. The results show that employing the velocity threshold in the MDPRR scheme can indeed reduce connection dropping probability, and make better usage of the reserved bandwidth. Copyright

Performance analysis of dynamic resource allocation with finite buffers in cellular networks

SUMMARY In this paper, we analyzed the performance of dynamic resource allocation with channel de-allocation and buffering in cellular networks. Buffers are applied for data traffic to reduce the packet loss probability while channel de-allocation is exploited to reduce the voice blocking probability. The results show that while buffering data traffic can reduce the packet loss probability, it has negative impact on the voice performance even if channel de-allocation is exploited. Although the voice blocking probability can be reduced with large slot capacity, the improvement decreases as the slot capacity increases. On the contrary, the packet loss probability increases as the slot capacity increases. In addition to the mean value analysis, the delay distribution and the 95% delay of data packets are provided.

Performance analysis of radio resource allocation for multimedia traffic in cellular networks

In this paper, we study the performance of radio resource allocation for cellular networks where real-time (RT) and non-real-time (NRT) data traffic are considered in addition to voice traffic. To guarantee the performance of voice traffic, preemptive priority is used so that voice calls can preempt data packets and RT data traffic preempts NRT data traffic. By reserving channels specifically for RT data, the packet loss probability and mean queueing delay can be reduced, meanwhile, the performance of NRT data can also be improved. This is achieved at the expense of increasing voice blocking probability. Thus, the number of reserved channels can be adjusted to control the voice blocking probability while improving the performance of data traffic. Besides, the packet loss probability of RT traffic is smaller for smaller RT traffic ratio. On the contrary, the smaller the RT traffic ratio, the larger the queueing delay.

Radio Resource Allocation in GSM/GPRS Networks

GPRS is a packet switched access mode for GSM system to improve wireless access to the Internet. In this paper, we study the design of radio resource allocation for GPRS and GSM services by allowing guard channels to be temporarily allocated to GPRS users to increase channel utilization. The call admission controller and channel allocation controller are employed to achieve good channel utilization and preserve the QoS of GSM services. Simulation results show that at low voice traffic load, there is no need to apply admission control to GPRS connections. While at high voice traffic load, applying call admission control to GPRS connections can guarantee the performance of voice service, but result in high GPRS connection blocking and low channel utilization. Furthermore, the QoS of voice service not being affected by the introduction of GPRS can be obtained by allowing voice arrivals to preempt the ongoing GPRS connections.