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The Han-Kobayashi (HK) encoding scheme is simplified for the one-sided Gaussian interference channel and a class of mixed interference channels, with Gaussian codebooks. The simplified region significantly decreases the computational complexity of the HK region. It also provides better insight into how to use the HK scheme for these channels. It shows that time-sharing with power allocation over two...
The rapid advancements in networking technologies and hand-held devices enable mobile users to concurrently receive real-time multimedia streaming (e.g., high-definition video) with different radio interfaces (e.g., Wi-Fi and LTE networks). Stream control transmission protocol (SCTP) is an important transport-layer solution to implement concurrent multipath transfer (CMT) over heterogeneous wireless...
This paper considers the problem of energy efficient beamforming allocation in a cellular wireless network. Unlike most of the existing work that considers the problem at the physical layer, we include in our analysis the impact of the bursty traffic patterns of the users. We formulate a stochastic optimization problem that minimizes the average transmit power of the network such that the queues of...
Compressed sensing (CS) provides a new method to encode depth videos, which utilizes the sparsity of depth maps to improve the coding efficiency. In this paper, we design a novel CS-based depth video codec. The codec adaptively decomposes blocks from 64 χ 64 to 8 χ 8 sub-blocks via wavelet transforming. The decomposition divides smooth regions and complex boundaries by frequencies, and minimizes the...
The scalable video coding consists in encoding the video content into multiple representations, called layers, where each one refers to a specific version of the content. The scalable extension of the High Efficiency Video Coding standard SHVC is currently considered in ATSC and DVB to carry out layered and scalable programs which enables to target multiple equipments, and is also used to ensure backward...
Parallel encoding systems face the problem of distributed coding decisions, an example of which is rate allocation between different encoding chunks. Distributed encoding is traditionally performed by assigning a fixed bitrate or quality setting to each chunk, after which the chunk uses rate control to achieve that particular target. In this paper, we discuss the use of constant-slope encoding, resulting...
Optimistic simulation yields impressive performance gains for many models. State saving is a quick way to provide the rollback mechanism required for this approach, but it has some drawbacks: it may not handle models with massive states or be able to support memory-constrained systems. This work presents a novel approach to state saving by storing only the relative changes caused by an event. Compressing...
In High Efficiency Video Coding (HEVC), the intra coding performance is significantly improved due to the recursive splitting structure and up to 35 intra prediction modes. However, the computational complexity of intra coding increases largely as well. In this paper, a fast intra coding scheme is proposed based on CPU and GPU cooperation. Firstly, the intra prediction of variable blocks is performed...
Whilst the pre-fabricated aspects of FPGAs have many advantages, the fixed nature of the underlying fabric limits the optimized synthesis of arithmetic circuits on these platforms. Many adder architectures, that suit ASICs have been implemented using FPGAs and it has long been established that for FPGAs the ripple carry adder gives the best performance in terms of speed and resource utilization. This...
Worldwide Interoperability for Microwave Access (WiMAX), which based on the IEEE 802.16-2009 standard is a serious competitor of Long Term Evolution (LTE) for cellular networks providing high data rates to mobile users. To support various multimedia applications the Quality of Service (QoS) support is a crucial function. This standard determines the air interface, including the medium access control...
Problems involving multi-agent systems can be complex and involve huge state-action spaces, making such problems difficult to solve. Function approximation schemes such as Kanerva coding with dynamic, frequency-based prototype selection can improve performance. However, selecting the number of prototypes is difficult and the approach often still gives poor performance. In this paper, we solve a collection...
This paper comprehensively studies the secure decode-and-forward (DF) relaying transmission in slow fading channels. To maximize the secrecy throughput under a secrecy outage probability constraint, we propose three adaptive transmission schemes (ATSs) with different complexity and flexibility, and design system parameters according to the instantaneous channel state information of the legitimate...
BT-Mode is a financing mode that the government using nongovernmental funds for the construction of infrastructure. It has greatly reduced the financial pressure of government because of BT-Mode does not contain operation period, the repurchase price is composed of construction cost and investment cost. If the construction investment is out of control, the repurchase price is inevitably on the high...
In this paper, the problem of jointly allocating bits, subcarriers and power to maximize the total transmit bit rate in an OFDM based cognitive radio (CR) is studied. Moreover, different service requirements of SUs are also considered. Since “underlay“ is adopted as the spectrum shared model, secondary users (SU) in the CR system are allowed to utilize any part of frequency band as long as the interference...
In this paper, we propose an improved design of expanding window fountain (EWF) codes over the binary input additive white Gaussian noise (BIAWGN) channels. The encoding process is modified to get almost regular variable node degree distributions. Compared with the conventional EWF codes, our proposed scheme can lower the error floor. Furthermore, we combine the EWF encoding process with unequal power...
Object-based audio techniques are becoming popular as they provide the flexibility for personalized rendering. For encoding multiple audio objects, a recent approach based on the intra-object sparsity was proposed. However, the allocation strategy of the number of preserved time-frequency (TF) instants (NPTF) utilized in this approach usually leads to an unbalanced perceptual quality for the decoded...
This paper deals with performance investigation of H.264/MPEG-4 video streaming, using unequal error protection (UEP) and turbo product coding (TPC) in wireless prone channels. Unequal amounts of protection are allocated to different frames (I, P and B frames) of a group-of-pictures (GOP) according to different contribution of such frames on video quality in case of error contamination. We have made...
Hybrid Automatic Repeat reQuest (HARQ) techniques are largely used in the context of wireless communications systems especially in the last few years, being employed in the latest cellular systems, including the Long Term Evolution (LTE) standard. Such schemes have been widely studied in literature; however, in this paper we are interested in applying the results of Polyanskiy-Poor-Verdù on the finite...
In this paper, the secrecy rate region of independent parallel multiple-carrier two-way secure communications with secure feedback is investigated. The legitimate user securely feeds back the secret key to the other legitimate user via secure feedback link in the presence of a passive eavesdropper, and the latter legitimate user encrypts confidential message with the received secret key. It is first...
The coherence directory in a chip-multiprocessor keeps track of each memory block inside the cache hierarchy and plays a significant role in offering a scalable shared memory abstraction in many-core systems. Multi-threaded applications typically require two types of directory entries, namely, limited pointer entries tracking a few sharers of a block and bitvector entries tracking larger number of...
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