163 research outputs found

    Multiplexing video traffic using frame-skipping aggregation technique.

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    by Alan Yeung.Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.Includes bibliographical references (leaves 53-[56]).Abstract also in Chinese.Chapter 1 --- Introduction --- p.1Chapter 2 --- MPEG Overview --- p.5Chapter 3 --- Framework of Frame-Skipping Lossy Aggregation --- p.10Chapter 3.1 --- Video Frames Delivery using Round-Robin Scheduling --- p.10Chapter 3.2 --- Underflow Safety Margin on Receiver Buffers --- p.12Chapter 3.3 --- Algorithm in Frame-Skipping Aggregation Controller --- p.13Chapter 4 --- Replacement of Skipped Frames in MPEG Sequence --- p.17Chapter 5 --- Subjective Assessment Test on Frame-Skipped Video --- p.21Chapter 5.1 --- Test Settings and Material --- p.22Chapter 5.2 --- Choice of Test Methods --- p.23Chapter 5.3 --- Test Procedures --- p.25Chapter 5.4 --- Test Results --- p.26Chapter 6 --- Performance Study --- p.29Chapter 6.1 --- Experiment 1: Number of Supportable Streams --- p.31Chapter 6.2 --- Experiment 2: Frame-Skipping Rate When Multiplexing on a Leased T3 Link --- p.33Chapter 6.3 --- Experiment 3: Bandwidth Usage --- p.35Chapter 6.4 --- Experiment 4: Optimal USMT --- p.38Chapter 7 --- Implementation Considerations --- p.41Chapter 8 --- Conclusions --- p.45Chapter A --- The Construction of Stuffed Artificial B Frame --- p.48Bibliography --- p.5

    A low-energy rate-adaptive bit-interleaved passive optical network

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    Energy consumption of customer premises equipment (CPE) has become a serious issue in the new generations of time-division multiplexing passive optical networks, which operate at 10 Gb/s or higher. It is becoming a major factor in global network energy consumption, and it poses problems during emergencies when CPE is battery-operated. In this paper, a low-energy passive optical network (PON) that uses a novel bit-interleaving downstream protocol is proposed. The details about the network architecture, protocol, and the key enabling implementation aspects, including dynamic traffic interleaving, rate-adaptive descrambling of decimated traffic, and the design and implementation of a downsampling clock and data recovery circuit, are described. The proposed concept is shown to reduce the energy consumption for protocol processing by a factor of 30. A detailed analysis of the energy consumption in the CPE shows that the interleaving protocol reduces the total energy consumption of the CPE significantly in comparison to the standard 10 Gb/s PON CPE. Experimental results obtained from measurements on the implemented CPE prototype confirm that the CPE consumes significantly less energy than the standard 10 Gb/s PON CPE

    An end-to-end adaptation algorithm for best effort video delivery over Internet.

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    by Walter Chi-Woon Fung.Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.Includes bibliographical references (leaves 64-[67]).Abstract also in Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Background --- p.1Chapter 1.2 --- Limitation of Existing Research --- p.3Chapter 1.3 --- Contributions of This Thesis --- p.3Chapter 1.4 --- Organization of the Thesis --- p.4Chapter 2 --- Related Work --- p.5Chapter 2.1 --- Ongoing Efforts For The Support of Real Time Applications on the Internet - RTP --- p.5Chapter 2.2 --- Using the Algorithm on top of RTP --- p.7Chapter 3 --- An Adaptive Video Retrieval Algorithm --- p.9Chapter 3.1 --- Lossless Environment --- p.9Chapter 3.1.1 --- Adapting the Request Rate to the Available Bandwidth --- p.12Chapter 3.2 --- Lossy Environment --- p.17Chapter 3.2.1 --- Adapting Ar in Lossy Environment --- p.20Chapter 3.3 --- Adjusting the Window Size --- p.24Chapter 3.4 --- Measurement Issues --- p.27Chapter 3.5 --- Mapping between Data Rate and Frame Rate --- p.28Chapter 4 --- Rate Measurement --- p.30Chapter 4.1 --- Arrival Rate Estimation --- p.30Chapter 4.2 --- Loss Rate Estimation --- p.32Chapter 5 --- Frame Skipping and Stuffing --- p.37Chapter 5.1 --- MPEG-1 Video Stream Basics --- p.37Chapter 5.2 --- Frame Skipping --- p.38Chapter 5.3 --- Frame Stuffing In Lossy Environment --- p.40Chapter 6 --- Experiment Result and Analysis --- p.43Chapter 6.1 --- Experiment --- p.43Chapter 6.2 --- Analysis --- p.54Chapter 6.2.1 --- Interacting With Streams With No Rate Control --- p.56Chapter 6.2.2 --- Multiple Streams Running The Algorithm --- p.58Chapter 6.2.3 --- Calculation of p --- p.59Chapter 7 --- Conclusions --- p.61Bibliography --- p.6

    FPGA based technical solutions for high throughput data processing and encryption for 5G communication: A review

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    The field programmable gate array (FPGA) devices are ideal solutions for high-speed processing applications, given their flexibility, parallel processing capability, and power efficiency. In this review paper, at first, an overview of the key applications of FPGA-based platforms in 5G networks/systems is presented, exploiting the improved performances offered by such devices. FPGA-based implementations of cloud radio access network (C-RAN) accelerators, network function virtualization (NFV)-based network slicers, cognitive radio systems, and multiple input multiple output (MIMO) channel characterizers are the main considered applications that can benefit from the high processing rate, power efficiency and flexibility of FPGAs. Furthermore, the implementations of encryption/decryption algorithms by employing the Xilinx Zynq Ultrascale+MPSoC ZCU102 FPGA platform are discussed, and then we introduce our high-speed and lightweight implementation of the well-known AES-128 algorithm, developed on the same FPGA platform, and comparing it with similar solutions already published in the literature. The comparison results indicate that our AES-128 implementation enables efficient hardware usage for a given data-rate (up to 28.16 Gbit/s), resulting in higher efficiency (8.64 Mbps/slice) than other considered solutions. Finally, the applications of the ZCU102 platform for high-speed processing are explored, such as image and signal processing, visual recognition, and hardware resource management

    Design and Analysis of Medium Access Control Protocols for Broadband Wireless Networks

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    The next-generation wireless networks are expected to integrate diverse network architectures and various wireless access technologies to provide a robust solution for ubiquitous broadband wireless access, such as wireless local area networks (WLANs), Ultra-Wideband (UWB), and millimeter-wave (mmWave) based wireless personal area networks (WPANs), etc. To enhance the spectral efficiency and link reliability, smart antenna systems have been proposed as a promising candidate for future broadband access networks. To effectively exploit the increased capabilities of the emerging wireless networks, the different network characteristics and the underlying physical layer features need to be considered in the medium access control (MAC) design, which plays a critical role in providing efficient and fair resource sharing among multiple users. In this thesis, we comprehensively investigate the MAC design in both single- and multi-hop broadband wireless networks, with and without infrastructure support. We first develop mathematical models to identify the performance bottlenecks and constraints in the design and operation of existing MAC. We then use a cross-layer approach to mitigate the identified bottleneck problems. Finally, by evaluating the performance of the proposed protocols with analytical models and extensive simulations, we determine the optimal protocol parameters to maximize the network performance. In specific, a generic analytical framework is developed for capacity study of an IEEE 802.11 WLAN in support of non-persistent asymmetric traffic flows. The analysis can be applied for effective admission control to guarantee the quality of service (QoS) performance of multimedia applications. As the access point (AP) becomes the bottleneck in an infrastructure based WLAN, we explore the multiple-input multiple-output (MIMO) capability in the future IEEE 802.11n WLANs and propose a MIMO-aware multi-user (MU) MAC. By exploiting the multi-user degree of freedom in a MIMO system to allow the AP to communicate with multiple users in the downlink simultaneously, the proposed MU MAC can minimize the AP-bottleneck effect and significantly improve the network capacity. Other enhanced MAC mechanisms, e.g., frame aggregation and bidirectional transmissions, are also studied. Furthermore, different from a narrowband system where simultaneous transmissions by nearby neighbors collide with each other, wideband system can support multiple concurrent transmissions if the multi-user interference can be properly managed. Taking advantage of the salient features of UWB and mmWave communications, we propose an exclusive region (ER) based MAC protocol to exploit the spatial multiplexing gain of centralized UWB and mmWave based wireless networks. Moreover, instead of studying the asymptotic capacity bounds of arbitrary networks which may be too loose to be useful in realistic networks, we derive the expected capacity or transport capacity of UWB and mmWave based networks with random topology. The analysis reveals the main factors affecting the network (transport) capacity, and how to determine the best protocol parameters to maximize the network capacity. In addition, due to limited transmission range, multi-hop relay is necessary to extend the communication coverage of UWB networks. A simple, scalable, and distributed UWB MAC protocol is crucial for efficiently utilizing the large bandwidth of UWB channels and enabling numerous new applications cost-effectively. To address this issue, we further design a distributed asynchronous ER based MAC for multi-hop UWB networks and derive the optimal ER size towards the maximum network throughput. The proposed MAC can significantly improve both network throughput and fairness performance, while the throughput and fairness are usually treated as a tradeoff in other MAC protocols

    A simulation-based algorithm for solving the resource-assignment problem in satellite telecommunication networks

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    This paper proposes an heuristic for the scheduling of capacity requests and the periodic assignment of radio resources in geostationary (GEO) satellite networks with star topology, using the Demand Assigned Multiple Access (DAMA) protocol in the link layer, and Multi-Frequency Time Division Multiple Access (MF-TDMA) and Adaptive Coding and Modulation (ACM) in the physical layer.En este trabajo se propone una heurística para la programación de las solicitudes de capacidad y la asignación periódica de los recursos de radio en las redes de satélites geoestacionarios (GEO) con topología en estrella, con la demanda de acceso múltiple de asignación (DAMA) de protocolo en la capa de enlace, y el Multi-Frequency Time Division (Acceso múltiple por MF-TDMA) y codificación y modulación Adaptable (ACM) en la capa física.En aquest treball es proposa una heurística per a la programació de les sol·licituds de capacitat i l'assignació periòdica dels recursos de ràdio en les xarxes de satèl·lits geoestacionaris (GEO) amb topologia en estrella, amb la demanda d'accés múltiple d'assignació (DAMA) de protocol en la capa d'enllaç, i el Multi-Frequency Time Division (Accés múltiple per MF-TDMA) i codificació i modulació Adaptable (ACM) a la capa física

    5G multimedia massive MIMO communications systems

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    In the fifth generation (5G) wireless communication systems, a majority of the traffic demands are contributed by various multimedia applications. To support the future 5G multimedia communication systems, the massive multiple-input multiple-output (MIMO) technique is recognized as a key enabler because of its high spectral efficiency. The massive antennas and radio frequency chains not only improve the implementation cost of 5G wireless communication systems but also result in an intense mutual coupling effect among antennas because of the limited space for deploying antennas. To reduce the cost, an optimal equivalent precoding matrix with the minimum number of radio frequency chains is proposed for 5G multimedia massive MIMO communication systems considering the mutual coupling effect. Moreover, an upper bound of the effective capacity is derived for 5G multimedia massive MIMO communication systems. Two antennas that receive diversity gain models are built and analyzed. The impacts of the antenna spacing, the number of antennas, the quality-of-service (QoS) statistical exponent, and the number of independent incident directions on the effective capacity of 5G multimedia massive MIMO communication systems are analyzed. Comparing with the conventional zero-forcing precoding matrix, simulation results demonstrate that the proposed optimal equivalent precoding matrix can achieve a higher achievable rate for 5G multimedia massive MIMO communication systems
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