32 research outputs found
Two-Way Relaying Cooperative Wireless Networks: Resource Allocation and Performance Analysis
Relay-based cooperative wireless networks have been widely considered one of the cost-effective solutions to meet the demands in future wireless networks. In order to maximize the overall sum-rate while maintaining proportional fairness among users, we investigate different resource allocation algorithms in two-way relay networks with analog network coding (ANC) protocol and time division broadcast (TDBC) protocol. The algorithms investigated are different from traditional proportional fairness schemes in terms of fairness and computational complexity as we have applied Access Proportional Fairness (APF) and Minimum Rate Proportional Fairness (MRPF) along with load balancing at the relays. A MATLAB simulation has been performed and simulation results show the effectiveness of these algorithms
Low Complexity Joint Sub-Carrier Pairing, Allocation and Relay Selection in Cooperative Wireless Networks
Multi-carrier cooperative relay-based wireless communication is of particular interest in future wireless networks. In this paper we present resource allocation algorithm in which sub-carrier pairing is of particular interest along with fairness constraint in multi-user networks. An optimization of sub-carrier pair selection is formulated through capacity maximization problem. Sub-carrier pairing is applied in both two-hop Amplify & Forward (AF) and Decode & Forward (DF) cooperative multi-user networks. We develop a less complex centralized scheme for joint Sub-carrier pairing and allocation along with relay selection. The computational complexity of the proposed algorithms has been analyzed and performance is compared with Exhaustive Search Algorithm
Benchmarking image codecs by assessment of coded test images: the development of test images and new objective quality metrics, Journal of Telecommunications and Information Technology, 2006, nr 1
Objective quality measures are required for benchmarking codec performance. Our aim was to develop a simple, accurate method capable of rapidly measuring the degree of blockiness, edge-blur and ringing due to image compression. Two test images were designed to emphasise these artefacts. The efficacy of the new metrics is demonstrated using a JPEG codec at a range of compression levels
Synthetic test patterns and compression artefact distortion metrics for image codecs : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Palmerston North, New Zealand
This thesis presents a framework of test methodology to assess spatial domain
compression artefacts produced by image and intra-frame coded video codecs. Few
researchers have studied this broad range of artefacts. A taxonomy of image and video
compression artefacts is proposed. This is based on the point of origin of the artefact
in the image communication model. This thesis presents objective evaluation of
distortions known as artefacts due to image and intra-frame coded video compression
made using synthetic test patterns. The American National Standard Institute
document ANSI T1 801 qualitatively defines blockiness, blur and ringing artefacts.
These definitions have been augmented with quantitative definitions in conjunction
with test patterns proposed.
A test and measurement environment is proposed in which the codec under test is
exercised using a portfolio of test patterns. The test patterns are designed to highlight
the artefact under study. Algorithms have been developed to detect and measure
individual artefacts based on the characteristics of respective artefacts. Since the
spatial contents of the original test patterns form known structural details, the artefact
distortion metrics based on the characteristics of those artefacts are clean and swift to
calculate. Distortion metrics are validated using a human vision system inspired
modern image quality metric.
Blockiness, blur and ringing artefacts are evaluated for representative codecs using
proposed synthetic test patterns. Colour bleeding due to image and video compression
is discussed with both qualitative and quantitative definitions for the colour bleeding
artefacts introduced. The image reproduction performance of a few codecs was
evaluated to ascertain the utility of proposed metrics and test patterns
Maximizing system throughput in multi-user cooperative relay networks
In this paper we address the resource allocation problem in cooperative relay network. We provide a comparative analysis of two basic protocols namely Amplify and Forward (AF) and Decode and Forward (DF), by implementing different sub-carrier allocation techniques with optimized power allocation. Our analysis is focused on total achievable system throughput and achievable individual throughput for each user
Radio Resource Allocation in Multi-User Cooperative Relaying Networks with Resource Block Pairing and Fairness Constraints
Multi-Carrier Cooperative Wireless Communication
This chapter provides a brief introduction about multi-carrier cooperative wireless communication systems using relays. We will describe some basic protocols that are being considered in relay operation. We will focus on the discussion of performance analysis and resource allocation in these systems. The performance analysis will be based on the system capacity
Compressed Sensing-Based Distributed Image Compression
In this paper, a new distributed block-based image compression method based on the principles of compressed sensing (CS) is introduced. The coding and decoding processes are performed entirely in the CS measurement domain. Image blocks are classified into key and non-key blocks and encoded at different rates. The encoder makes use of a new adaptive block classification scheme that is based on the mean square error of the CS measurements between blocks. At the decoder, a simple, but effective, side information generation method is used for the decoding of the non-key blocks. Experimental results show that our coding scheme achieves better results than existing CS-based image coding methods