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The authors propose a new power saving scheme based on a buffer-threshold and timer in wireless packet networks. In a standard sleep mode operation with a binary exponential algorithm, a mobile station (MS) can begin a wake period if it is aware of the existence of its own downlink packets during a listening interval. In a light traffic environment, this conventional standard operation consumes a considerable amount of power to switch modes (sleep/listen/wake). To solve this problem, a new power saving scheme based on joint control of buffer-threshold and timer (JCBT) is proposed. To see the performance behaviour of the JCBT scheme, the authors consider the total power consumption per unit time and the average packet transfer delay as performance measures. Based on the performance measures, the authors obtain the optimal solution for the proposed JCBT scheme that minimises the total power consumption per unit time with a given delay requirement. [ABSTRACT FROM AUTHOR]

Long-term evolution-advanced (LTE-A), the true 4G technology of third Generation Partnership Project family, has a new feature that aggregates multiple LTE carriers so that users can be served on multiple component carriers (CCs). This characteristic plays an important role to increase data rate multiple times for LTE-A users with corresponding multiple CCs. However, current proposed packet scheduling (PS) algorithms ignore this effect in the effort of providing new solution that increases system performance. The modified proportional fair algorithms proposed in this study can provide optimised algorithm for PS mechanism in LTE-A system as well as other technologies that use multiple carriers. [ABSTRACT FROM AUTHOR]

IEEE 802.15.4 standard applies the slotted carrier sense multiple access with collision avoidance (CSMA/CA) for its contention mechanism in the contention access period (CAP). In CAP, channel utilisation is significantly affected by backoff time and collision. A delayed backoff algorithm (DBA) in CAP is proposed for the beacon-enabled networks. DBA improves the goodput and power consumption by decreasing the backoff time between packets and assuring that the different nodes will not finish their backoffs at the same time. Simulation results show that the proposed algorithm outperforms the slotted CSMA/CA and other schemes in terms of goodput and power consumption. [ABSTRACT FROM AUTHOR]

Packet scheduling is a vital component to support different classes of service in all-packet networks. In classical queuing systems, the waiting-time performance of non-first in first out buffer scheduling systems could be predicted through the use of analysis. However, all-packet networks feature traffic patterns that do not conform to classical Poisson-like processes, and this greatly complicates the evaluation of their performance. Our novel approach to this problem is through a hybrid combination of analysis and simulation. The authors derive a combinatorial algorithm, using the generalised ballot theorem, which predicts waiting times for low-priority traffic. When this algorithm is combined with prior work on traffic aggregation, the authors achieve a significant reduction in the state space associated with the buffer under study. To numerically test this algorithm, the authors demonstrate its use in simulation, where state space and event count reduction is a fundamental requirement to ensure experiments complete in a timely fashion. Numerical results from these simulations show a very significant reduction in the number of events processed combined with improved state coverage. This is achieved while maintaining a highly accurate representation of packet delays compared with a conventional approach. [ABSTRACT FROM AUTHOR]

A new scheduling algorithm called serialised batch scheduling (SBS) for optical burst switching (OBS) networks is proposed. SBS aggregates and serialises bursts along a shared path into one composite burst, which is switched as one unit. There are two major processes in SBS, namely, batching and serialising. While the batching process chooses a set of bursts to form the composite burst, the serialising process determines how to organise the OBS bursts within the composite burst and generates a corresponding control packet for this burst. Several SBS batching and serialising schemes are introduced and analysed here. The study by the authors shows that the guard band and burst overlap can be reduced in the SBS and, thus, the packet loss rate and the number of switch reconfigurations can be significantly reduced. In addition, it is indicated that the proposed SBS algorithm can be coupled with other OBS scheduling algorithms and reduce the requirements for a high-speed optical switch in OBS networks. [ABSTRACT FROM AUTHOR]

The author evaluates the performance of bufferless optical packet switches equipped with shared tuneable optical wavelength converters (TOWC) and supporting the quality of service (QoS). The TOWCs are shared per output fibre and, hence each output fibre has a dedicated pool of TOWCs. The TOWCs are not completely shared within the node. The QoS, expressed in terms of the packet loss probability, is differentiated by giving the packets different priorities in accessing both the output wavelengths and the TOWCs. A scheduling algorithm is proposed and its complexity is evaluated. The QoS technique's effectiveness is studied by means of an analytical model based on a probabilistic approach and validated by simulation results. The results show that the proposed technique to support the QoS facilitates a good differentiation of the QoS offered to packets. [ABSTRACT FROM AUTHOR]