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Widely-used Rate Control (RC) algorithms, such as those in the H.264 encoder, have certain shortcomings for time-sensitive applications such as High Definition Video Conferencing (HDVC): they either respond too slowly to available bandwidth variations, causing degradation in the perceived quality of the video session, or do not optimize video quality for a given available bandwidth. To overcome these...
One Dimensional (1D) Double Weight (DW) code families are one of the coding schemes reported for Spectral Amplitude Coding — Optical Code Division Multiple Access systems. Modified Double Weight code and Enhanced Double Weight code are two algorithms which increase the scope of DW code for even and odd weights respectively. By using above mentioned codes, two Dimensional (2D) codes are generated....
The intense demand for video applications from mobile devices brings a challenge to the hardware design, especially in the energy consumption. This work presents a design space exploration to define energy-efficient cache memory configurations for the ME process considering different video sequences and HEVC encoder configurations. We focus on the Motion Estimation (ME) process, known as the most...
Virtual reality (VR) applications target high-quality and zero-latency scene navigation to provide users with a full-immersion sensation within a scene. From a network perspective, this requires transmission of the omnidirectional content in its entirety, at a high resolution, which is not always feasible in bandwidth-limited networks. In this work, we propose an optimal transmission strategy for...
Fault tolerance is a major issue for all storage service providers. Currently, the storage service providers make use of data replication as a method to ensure fault tolerance. In the big data era, relying on data replication for fault tolerance reduces the storage efficiency. Most of the modern applications make use of erasure code based storage systems as an alternative to the data replication....
Good user experience with interactive cloud-based multimedia applications, such as cloud gaming and cloud-based VR, requires low end-to-end latency and large amounts of downstream network bandwidth at the same time. In this paper, we present a foveated video streaming system for cloud gaming. The system adapts video stream quality by adjusting the encoding parameters on the fly to match the player's...
An ultra-wideband metasurface is designed for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultrawideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle...
Erasure codes are widely used in practical storage systems to prevent disk failure and data loss. However, these codes require excessive disk I/Os and network traffic for recovering unavailable data. As a result, the recovery performance of erasure codes is suboptimal. Among all erasure codes, Minimum Storage Regenerating (MSR) codes can achieve optimal repair bandwidth under the minimum storage during...
Erasure coding has been widely adopted to protect data storage against failures in production data centers. Given the hierarchical nature of data centers, characterizing the effects of erasure coding and redundancy placement on the reliability of erasure-coded data centers is critical yet largely unexplored. This paper presents a comprehensive simulation analysis of reliability on erasure-coded data...
The WRGB-OLED with larger-sized display resolution can bring us more colorful and better visual experiences. However, it also makes OLED display system suffer from a serious bottleneck on memory bandwidth. In this paper, the lossless pixel-gradient EC algorithm is proposed to overcome this bottleneck. It consists of two core techniques: Finer-Gradient-Based Prediction (FGBP) and Gradient-Based Golomb-Rice...
Novel technologies based on pulse amplitude modulation (PAM) are studied for a high-speed visible light communication (VLC) system. In this paper, we summarize the latest progress on high-speed PAM-VLC systems including phase shifted Manchester coding, Nyquist filter, weighted pre-equalization, multi-band access, and hybrid time-frequency domain equalization, which supporting VLC high data-rate and...
The deployment of smart grid communication networks (SGCN) in urban areas has been possible due to the huge availability of wired and wireless communication technologies. However, in rural areas, those communications options are usually not available, unsuitable and/or too costly, making the deployment of a SGCN more challenging in such a case. On the other hand, the recently introduced low power...
Distributed storage systems are composed by many unreliable storage nodes over a network. A data file is redundantly stored in multiple storage nodes to provide high reliability. Recently erasure codes with Maximum Distance Separable (MDS) property are gradually employed in distributed storage systems to reduce the cost of reliably storing large amounts of data. Regenerating codes are a class of erasure...
Network coding has shown the promise of significance throughput improvement. In this paper, we study the throughput of two-hop wireless network coding and explore how the maxi-mum throughput can be achieved under a random medium access scheme. In this paper, the problem of the performance of COPE type network coding under dual source coding architecture is solved. An Embedded Markov Chain Model for...
In this paper, we propose, design, and evaluate the use of transmitters mapping with a symbols encoding techniques to mitigate inter-symbol interference (ISI) and improve the overall VLC system performance while using a very simple receiver (single element wide field of view, (FOV)) with an OOK modulation scheme. The proposed technique with the laser diodes transmitters are able to provide data rates...
Distributed file systems enable the reliable storage of exabytes of information on thousands of servers distributed throughout a network. These systems achieve reliability and performance by storing multiple copies of data blocks in different locations across the network. The management of these copies of data is commonly handled by intermediate servers that track and coordinate the placement of data...
Nowadays small satellites are promising tools for space research and communication. However, size restrictions are also limits for power consumption and capacity. One of the ways to improve the throughput is the use appropriate modulation and coding schemes. A suitable channel model was chosen and link budgets were calculated for the appropriate choice of modulation and coding. Different types of...
In this paper, we address the need for motivating applications, such as mission critical industrial control and medical applications, to operate under the Ultra-Reliable Communication (URC) mode in the future 5th Generation (5G) cellular wireless networks, while also under strict Quality of Service (QoS) constraints such as ultra-low latency. Reliability has been shown to improve by using Hybrid Automatic...
We investigate the overlay coding scheme as the capacity achieving multi user detection (MUD) technique, i.e., transmitting over non-orthogonal channels, in forward link in multi-beam satellite systems with dense frequency reuse. The classic overlay coding scheme, uses the strongest co- channel interference (CCI) as extra source of information. The data intended for the target user is shared between...
We consider the {n, k, d, l) secure exact-repair regenerating code problem, which generalizes the {n, k, d) exact-repair regenerating code problem with the additional constraint that the stored file needs to be kept information-theoretically secure against an eavesdropper, who can access the data transmitted to regenerate a total of l different failed nodes. For all known results on this problem,...
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