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We study an online problem that occurs when the capacities of machines are heterogeneous and all jobs are identical. Each job is associated with a subset, called feasible set, of the machines that can be used to process it. The problem involves assigning each job to a single machine in its feasible set, i.e., to find a feasible assignment. The objective is to maximize the throughput, which is the...
The increasing demand for high bandwidth in cellular wireless networks led to a dramatic increase in the number of deployed LTE femtocell base stations (FBS) in recent years. While the energy consumed by a single FBS is relatively negligible, the collective energy footprint of all FBSs deployed by an operator turns out to be huge. Energy-efficient protocols are needed thus to balance the trade-off...
60GHz communication is a promising technology for future multimedia applications in WPANs with its capability of supporting Giga-bit transmission in a short range. However, 60GHz signal degrades significantly through obstacles. Therefore, collaborative transmission is preferred to solve the link blocking problem. Furthermore, the utilization of directional antenna, which aims to offset the severe...
In cognitive radio network (CRN), the utilization of wireless spectrum can be dramatically improved with the secondary user (SU) opportunistically access the licensed channels. With the help of spectrum sensing technology, the SU can dynamically access a large number of spectrum holes. However, how to allocate the spectrum holes between SUs becomes a thorny problem. The utilization of proper allocation...
Seamless rate adaptation (SRA) is one of the promising rate adaptive schemes for wireless communication system. However, the high complexity of decoding hinders its application. We propose an optimized Application-specific integrated circuit (ASIC) design and implementation for SRA decoder in this paper. In order to balance speed and resource consumption, a partial parallel architecture is used in...
Recently, the research on rate adaption at receiver has caused widespread concern. Seamless rate adaptive (SRA) is one of the promising rate adaptation schemes for wireless communication system. However, the high complexity of decoding hinders its application. The graphics processor unit (GPU) is able to provide a low-cost and flexible software-based multi-core architecture for high performance computing...
In this paper we study the problem of throughput maximization, with fairness guarantee, in multi-cell WLANs with hidden terminals. In such a scenario, the throughput gained by each flow is generally determined by the four major control mechanisms that make the basis of WLAN control protocols - viz., radio frequency channel assignment, association control, intra-AP airtime sharing between the associated...
In this paper we study the problem of joint client association, airtime sharing and contention resolution in IEEE802.11 multi-cell WLANs with directional antennas with the goal of achieving optimal fair throughput. We formulate the problem as a non-linear programming problem and solve it under the network utility maximization framework. Using simulation, we demonstrate that i) the association pattern...
In this paper we study the problem of client association, airtime sharing and contention resolution in a multi-cell WLAN to achieve fair download bandwidth sharing. We first model the problem as a utility maximization problem, then, because of the integral nature of association, the problem being NP-hard, we decompose it into two sub-problems: the client association problem on one hand, and the joint...
The performance of carrier sense multiple access (CSMA) in an unslotted multi-channel cognitive radio network under non-saturation condition is studied. In this system, every secondary user in idle state generates a new file after exponential distributed time and randomly generates a file which consists of geometrically distributed number of packets. We model the above described unslotted cognitive...
In this paper we study the problem of client association, jointly with airtime sharing and contention resolution in a multi-cell WLAN with hidden terminals with the objective of achieving proportional fair download bandwidth allocation to the clients. We first formulate the problem as a utility maximization problem, which, due to the integral nature of association turns out to be a 0–1 (NP-hard) programming...
To solve the discontinuity of available spectrum in the cognitive radio network, a graph coloring based on aggregation spectrum assignment method is proposed. By aggregate discontinuous spectrum holes in the cognitive network, the proposed method assigns the spectrum according maximizing throughput and fairness. Compared with the traditional continuous spectrum assignment method, it can enhance the...
As in many other parts of the world, overcrowding in Taiwan's hospital Emergency Departments (ED) is an increasingly scrutinized area. EDs in Taiwan hospitals must implement efficient systems that minimize costs while also providing satisfactory levels of care. The primary goal of this investigation is to develop and deploy a mixed method incorporating Discrete Event Simulation (DES) and Data Envelopment...
To maximize the utilization of system resources with satisfying diverse quality of service (QoS) requirements, a novel multiple utility factors-based parallel (MUFP) packet scheduling algorithm is proposed for the broadcast base station (BBS) and cell base station (CBS) mixed mode of broadband wireless multimedia (BWM) systems. MUFP takes into consideration QoS requirements, queue dynamics and channel...
This paper proposes a dynamic coding policy (MSNC) which allows network coding applied across multiple sessions and develops a necessary condition for MSNC by denoting the benefit gaining from coding. With MSNC, intermediate nodes can independently judge whether the coding operation is appropriate and easily decide which packet to transmit among the incoming flows. To make the network coding feasible...
To maximize the utilization of system resources and satisfy the requirements for quality of service (QoS), the radio resource joint management (RRJM) scheme is proposed for the broadcast base station (BBS) and cell base station (CBS) mixed mode of broadband wireless multimedia (BWM) system. The RRJM includes multiple utility factors-based packet scheduling (MUFPS) and broadcast cell seamless handover...
In this paper, we seek the optimal overlay multicast performance for scalable video streaming. To adapt to layered multicast with multiple paths, a new metric layer stretch is introduced, measuring video layer's dissemination latency along the overlay. Multi-path routing, network coding based layer subscription and congest control are jointly optimized, formulating a linear programming to minimize...
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