Slanted Frame Arrangement on Multiple Frequency Carriers in TDD Based PRMA

Efficient utilization of radio resource is one of the most important issues in wireless systems. In existing TDD based PRMA protocol and its variations, a mobile terminal is assigned on one of the frequency carriers after completing a registration procedure. Since mobile terminals enter and leave the system in an unpredictable fashion, some of the frequency carriers may become heavily loaded while other frequency carriers are underutilized. The frequency carriers can be utilized more efficiently by allowing the mobile terminals to switch among the frequency carriers. To enable the mobile terminals to switch among the frequency carriers efficiently, this paper proposes to arrange the frame boundaries on the frequency carriers in a slanted fashion. A scheme is proposed to enable a mobile terminal to switch among different frequency carriers such that shorter time is required to obtain a slot at the beginning of a talk spurt or a burst of data. Simulations are performed to compare the performance of the proposed scheme with a scheme that does not allow mobile terminals to switch among frequency carriers. Our simulation results show that the proposed slanted frame arrangement scheme yields significantly lower mean request waiting time and packet dropping ratio.     

A novel auxiliary graph model for effective dynamic traffic grooming in light-trail optical WDM mesh networks

Photonic Network Communications - The SDN paradigm profoundly affects the architecture of networks in favor of more adaptability to the needs for new value-added services. This article examines the...     

An approximate analysis of the join the shortest queue (JSQ) policy

This paper presents an accurate analytical model for evaluating the performance of the join the shortest queue (JSQ) policy. The system considered consists of N identical queues each of which may have single or multiple servers. A birth-death Markov process is used to model the evolution of the number of jobs in the system. Our results show that this method provides very accurate estimates of the average job response times     

Minimizing the Number of Multicast Transmissions in Single-Hop WDM Networks

The problem of minimizing the number of transmissions for a multicast transmission under the condition that the packet delay is minimum in single-hop wavelength division multiplexing (WDM) networks is studied in this paper. This problem is proved to be NP-complete. A heuristic multicast scheduling algorithm is proposed for this problem. Extensive simulations are performed to compare the performance of the proposed heuristic algorithm with two other multicast scheduling algorithms, namely, the greedy and no-partition scheduling algorithms. The greedy algorithm schedules as many destination nodes as possible in the earliest data slot. The no-partition algorithm schedules the destination nodes of a multicast packet to receive the packet in the same data slot without partitioning the multicast transmission into multiple unicast or multicast transmissions. Our simulation results show that (i) an algorithm which partitions a multicast transmission into multiple unicast or multicast transmissions may not always produce lower mean packet delay than the no-partition algorithm when the number of data channels in the system is limited and (ii) the proposed heuristic algorithm always produces lower mean packet delay than the greedy and the no-partition algorithms because this algorithm not only partitions a multicast transmission into multiple unicast or multicast transmissions to keep the packet delay low but also reduces the number of transmissions to conserve resources.