ieeE 802.16 standard suite defines a reservation-based bandwidth allocation mechanism. A SS (Subscriber Station) has to be polled to request bandwidth reservation before transmits uplink data to a BS (Base Station). I...
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This paper studies a balanced power allocation scheme to approach the capacity limits and power consumption reduce simultaneously of orthogonal-frequency-division-multiplexing multiple-input multiple-output(OFDM-MIMO)...
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ISBN:
(纸本)9780769532905
This paper studies a balanced power allocation scheme to approach the capacity limits and power consumption reduce simultaneously of orthogonal-frequency-division-multiplexing multiple-input multiple-output(OFDM-MIMO) channels under the assumption that perfect channel state information (CSI) is available at both the transmitter and the receiver In this paper We build a function to describe the coordinate performance of capacity and total power and use convex optimization method to solve this question, and an adaptive power allocation scheme is proposed according to the interior-point method. By numerical example we verify our analysis and show that proposed approach, compared to the optimal water-filling algorithm, actually achieves significantly lower total power consumption with similar performance in capacity.
Based on color histogram, a new search method is presented in this paper. Firstly, the image is divided into background and target through the threshold. And then the target image is split into fan-shaped isometric re...
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ISBN:
(纸本)9780769532905
Based on color histogram, a new search method is presented in this paper. Firstly, the image is divided into background and target through the threshold. And then the target image is split into fan-shaped isometric region. Calculate the third-order moment as feature vectors and realize image retrieval by the similarity comparing between the images. This method not only rules out background interference, but also reflects the position of the goals. Experimental results show that this improved approach is better than the simple use of color histogram in an accurate survey.
OFDM is a modulation scheme which is effective against multipath distortion. It has also high bandwidth efficiency. OFDM is, in fact, a multicarrier modulation method in which the available bandwidth of the channel is...
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ISBN:
(纸本)9780769532905
OFDM is a modulation scheme which is effective against multipath distortion. It has also high bandwidth efficiency. OFDM is, in fact, a multicarrier modulation method in which the available bandwidth of the channel is divided into subcarriers, and data symbols are modulated and transmitted on each subcarrier simultaneously. However, one of the most important drawbacks of this system is the large Peak-to-Average-Power Ratio (PAPR) of the transmit signal. A large PAR increases the complexity of the DAC and ADC converters and reduces efficiency of the RF power amplifier. Tone Injection is a promising technique for PAR reduction based on general additive method This algorithm doesn't reduce transmission rate but increase the average power of transmit signal. Furthermore, the complexity of TI method is high. To reduce the complexity, two new algorithms are proposed in this paper.
Wireless sensor networks have been widely used in many important areas. Medium access control(MAC) protocols have a significant effect on the function and performance of sensor networks. Though the TDMA-based MAC prot...
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ISBN:
(纸本)9780769532905
Wireless sensor networks have been widely used in many important areas. Medium access control(MAC) protocols have a significant effect on the function and performance of sensor networks. Though the TDMA-based MAC protocols are inherently collision free and can rule out idle listening since nodes know when to transmit, it is difficult to change the frame size and time slot assignment due to network topology or traffic load changes. In this paper, we present an energy-efficient TDMA protocol for clustered wireless sensor networks(EC-TDMA), which is an intra-cluster communication MAC protocol. EC-TDMA dynamically changes the length of TDMA frame according to the number of sensor nodes and the sensor node traffic load within a cluster, reduces the idle listening and improves channel utility, thus prolongs networks lifetime. The simulation results show that this prolocl performs better than existing protocols in the average energy consumption, packet delivery ratio and average latency.
In this paper, a joint source-channel coding (JSCC) scheme for unequal error protection (UEP) based H. 264 over wireless channels is proposed H.264 coded information is divided into different parts according to their ...
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ISBN:
(纸本)9780769532905
In this paper, a joint source-channel coding (JSCC) scheme for unequal error protection (UEP) based H. 264 over wireless channels is proposed H.264 coded information is divided into different parts according to their different importance, each part is transmitted differentially based on MMO-OFDM system by applying unequal number of information bits in channel error-correction code to achieve unequal error protection. The combination of MMO and OFDM improves significantly capacity of the system and overcome the frequency selective effects of broadband wireless channel. Simulation results show that the scheme can obviously improve the error resilience compared to EEP, especially when the channel is in bad condition. So the scheme is suitable to fluctuant channel with large range.
The computation of the frequency response of systems depending affinely on uncertain parameters can be reduced to that of all its one-dimensional edge plants while the image of such an edge plant at a fixed frequency ...
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The computation of the frequency response of systems depending affinely on uncertain parameters can be reduced to that of all its one-dimensional edge plants while the image of such an edge plant at a fixed frequency is an arc or a line segment in the complex plane. Based on this conclusion, four computational formulas of the maximal and minimal (maxi-mini) magnitudes and phases of an edge plant at a fixed frequency are given. The formulas, besides sharing a simpler form of expression, concretely display how the extrema of the frequency response of the edge plant relate to the typical characteristics of the arc and line segment such as the centre, radius and tangent points of the arc, the distance from the origin to the line segment etc. The direct application of the results is to compute the Bode-, Nichols-and Nyquist-plot collections of the systems which are needed in robustness analysis and design.
The proceedings contains 8 papers from ieecolloquium on computing and controldivision 'Intelligent Design Systems'. Topics discussed include: design for testability of printed circuit board (PCB) assemblies;...
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The proceedings contains 8 papers from ieecolloquium on computing and controldivision 'Intelligent Design Systems'. Topics discussed include: design for testability of printed circuit board (PCB) assemblies;quality improvement in PCB assembly design;logic-based model of prosthesis design;avoiding 'build-to-print' in polymer composites: design and manufacturing decision support at the conceptual stages;enabling intelligent variant design using constraints;prospects for intelligent PCB design;computer based empirical models for the analysis of conceptual designs;engineering design support through case-based reasoning;and supporting the process of re-use in innovative design environments.
Journal publishes the materials of the colloquium on computing and controldivision 'Technologies Supporting the Remote Delivery of Health and Care Services'. The proceedings contains 7 papers. The aim of this...
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Journal publishes the materials of the colloquium on computing and controldivision 'Technologies Supporting the Remote Delivery of Health and Care Services'. The proceedings contains 7 papers. The aim of this colloquium was to enable those developing or implementing technology based systems to support the remote delivery of health and care services to learn of ongoing developments and together consider of the issues affecting the successful introduction and use of technology in this field.
The proceedings contains 7 papers from the COTS and Safety Critical Systems. Topics discussed include: the Commercial Off-The-Shelf (COTS) technology as an expensive solution;application of COTS in aerospace gas turbi...
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The proceedings contains 7 papers from the COTS and Safety Critical Systems. Topics discussed include: the Commercial Off-The-Shelf (COTS) technology as an expensive solution;application of COTS in aerospace gas turbine engine control;airborne COTS hardware;control of COTS risks;programming interfaces for COTS;and supporting the use COTS in safety critical applications.
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