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Quality of Service (QoS) routing is one of the key enabling techniques for multimedia wireless sensor networks (WSNs). However, the multi-constraints QoS routing problem is an NP-hard problem, and the computational complexity of an exhaustive search over all the paths is too high for large scale multimedia WSNs. In this paper, a novel parallel elite clonal quantum evolutionary algorithm is proposed...
Virtual Multiple-Input Multiple-Output (MIMO) is a promising uplink technology that can meet the throughput demand of Long-Term Evolution-Advanced (LTE-A) systems. However, the complexity of scheduling virtual MIMO is a challenge; existing virtual MIMO is therefore limited to best effort applications. We investigate the resource allocation and scheduling problem in a heterogeneous virtual MIMO system...
Cognitive radio (CR) has been an enabling technology for secondary users (SUs) to efficiently exploit radio spectrum underutilized by primary users (PUs). To avoid downgrading PUs' performance, dynamic spectrum access (DSA) plays an important role in CR networks (CRNs) for adaptively assigning spectrum to SUs. During spectrum handover to PUs, quality of service (QoS) of SUs may not be satisfied due...
The emerging technology of cognitive radio (CR) allows secondary users (SUs) to gain access to radio spectrum which is licensed to but temporarily unoccupied by primary users (PUs). Apart from spectrum sensing, dynamic spectrum access (DSA) is an important processing task for CR networks (CRNs). Its aim is to allocate spectrum for SUs dynamically without causing any harm to PUs. CRNs may support different...
Quality of Service (QoS) and queue management are critical issues for broadcast scheme of IEEE 802.11 systems in Vehicular Ad hoc Networks (VANETs). However, existing 1-dimensional models of broadcast scheme in VANETs are unable to capture the complete QoS performance and queueing behavior due to the lack of an adequate finite buffer model. We present a 2-dimensional Markov chain that integrates the...
802.11e enhanced distributed channel access (EDCA) introduces different parameters to provide differentiated QoS support for various traffic classes. This brings additional difficulties and complexities to the traditional per-slot based Markov chain modeling techniques, where the transmission probability relies on generic time slots. Channel access cycle based modeling, which does not depend on per-slot...
We consider the downlink transmit power allocation problems in multi-user MIMO wireless networks using zeroforcing beamforming. Traditionally such problems are solved by water-filling algorithm under the assumption of perfect channel knowledge. However when channel information is not known a priori or time varying the water-filling solution is shown to be unstable. We use the sliding mode control...
Networked control systems typically involve multiple subsystems which share the communication network. In this system setting, besides the optimization of the quality of control of the considered networked control system, the efficient utilization of the communication resources contributes to part of the overall control objective. By realizing the fact that the packet delay variation can be roughly...
We consider the impacts of channel fading on the quality of service (QoS) performance of the IEEE 802.11 system. Traditional 2-D Markov chain models, while suitable for throughput analysis, are unable to capture the QoS performance due to the lack of a proper queueing model. We present a 3-D Markov chain queueing model that incorporates channel fading effects and solve the Markov chain efficiently...
In fire fighting having prompt and reliable tracking and communication in case of emergency is of paramount importance. We developed an integrated positioning, sensing and communication platform for tracking first responders in urban fire fighting. A Quality of Service (QoS) enabled TDMA MAC (QT-MAC) was designed to provide a low latency and high reliability service for critical data transfer, as...
The capture effect can occur in IEEE 802.11 distributed coordination function (DCF) wireless systems when packets arrive with different powers. Packets with high power can effectively swamp low power packets, such that they are received successfully, when otherwise a collision would have occurred. We present a network performance prediction model that accurately incorporates the capture effect into...
We present a new approach for end-to-end QoS that biases per-hop behavior based on performance necessary for a packet to meet end-to-end QoS goals. Class based servicing of traffic is augmented with decisioning that considers the likelihood that a packet will meet end-to-end requirements for mission success. Theoretical analysis is verified with OPNET simulations to show a potential for greater than...
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