An adaptive quasi harmonic broadcasting scheme with optimal bandwidth requirement

The aim of Harmonic Broadcasting protocol is to reduce the bandwidth usage in video-on-demand service where a video is divided into some equal sized segments and every segment is repeatedly transmitted over a number of channels that follows harmonic series for channel bandwidth assignment. As the bandwidth of channels differs from each other and users can join at any time to these multicast channels, they may experience a synchronization problem between download and playback. To deal with this issue, some schemes have been proposed, however, at the cost of additional or wastage of bandwidth or sudden extreme bandwidth requirement. In this paper we present an adaptive quasi harmonic broadcasting scheme (AQHB) which delivers all data segment on time that is the download and playback synchronization problem is eliminated while keeping the bandwidth consumption as same as traditional harmonic broadcasting scheme without cost of any additional or wastage of bandwidth. It also ensures the video server not to increase the channel bandwidth suddenly that is, also eliminates the sudden buffer requirement at the client side. We present several analytical results to exhibit the efficiency of our proposed broadcasting scheme over the existing ones.Comment: IEEE International Conference on Informatics, Electronics & Vision (ICIEV), 2013, 6pages, 8 figure

Design and Validation of a Software Defined Radio Testbed for DVB-T Transmission

This paper describes the design and validation of a Software Defined Radio (SDR) testbed, which can be used for Digital Television transmission using the Digital Video Broadcasting - Terrestrial (DVB-T) standard. In order to generate a DVB-T-compliant signal with low computational complexity, we design an SDR architecture that uses the C/C++ language and exploits multithreading and vectorized instructions. Then, we transmit the generated DVB-T signal in real time, using a common PC equipped with multicore central processing units (CPUs) and a commercially available SDR modem board. The proposed SDR architecture has been validated using fixed TV sets, and portable receivers. Our results show that the proposed SDR architecture for DVB-T transmission is a low-cost low-complexity solution that, in the worst case, only requires less than 22% of CPU load and less than 170 MB of memory usage, on a 3.0 GHz Core i7 processor. In addition, using the same SDR modem board, we design an off-line software receiver that also performs time synchronization and carrier frequency offset estimation and compensation

Scalable reliable on-demand media streaming protocols

This thesis considers the problem of delivering streaming media, on-demand, to potentially large numbers of concurrent clients. The problem has motivated the development in prior work of scalable protocols based on multicast or broadcast. However, previous protocols do not allow clients to efficiently: 1) recover from packet loss; 2) share bandwidth fairly with competing flows; or 3) maximize the playback quality at the client for any given client reception rate characteristics. In this work, new protocols, namely Reliable Periodic Broadcast (RPB) and Reliable Bandwidth Skimming (RBS), are developed that efficiently recover from packet loss and achieve close to the best possible server bandwidth scalability for a given set of client characteristics. To share bandwidth fairly with competing traffic such as TCP, these protocols can employ the Vegas Multicast Rate Control (VMRC) protocol proposed in this work. The VMRC protocol exhibits TCP Vegas-like behavior. In comparison to prior rate control protocols, VMRC provides less oscillatory reception rates to clients, and operates without inducing packet loss when the bottleneck link is lightly loaded. The VMRC protocol incorporates a new technique for dynamically adjusting the TCP Vegas threshold parameters based on measured characteristics of the network. This technique implements fair sharing of network resources with other types of competing flows, including widely deployed versions of TCP such as TCP Reno. This fair sharing is not possible with the previously defined static Vegas threshold parameters. The RPB protocol is extended to efficiently support quality adaptation. The Optimized Heterogeneous Periodic Broadcast (HPB) is designed to support a range of client reception rates and efficiently support static quality adaptation by allowing clients to work-ahead before beginning playback to receive a media file of the desired quality. A dynamic quality adaptation technique is developed and evaluated which allows clients to achieve more uniform playback quality given time-varying client reception rates

Relay selection methods for maximizing the lifetime of wireless sensor networks

Combined analytical and fuzzy techniques are proposed for improving the battery lifetime, performance, as well as energy efficiency of wireless sensor networks (WSNs) with the aid of efficient relay selection methods. We determine the best relay selection method by striking an appealing performance versus network lifetime trade-off. Furthermore, the beneficial regions of cooperation are determined considering asymmetric traffic scenarios, where relaying provides energy saving

Design and implementation of a consonant broadcasting architecture for large-scale video streaming.

Liu Wing Chun.Thesis submitted in: July 2003.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves 55-57).Abstracts in English and Chinese.Acknowledgement --- p.IAbstract --- p.II摘要 --- p.IIIChapter Chapter 1 --- Introduction --- p.1Chapter Chapter 2 --- Related Works --- p.5Chapter 2.1 --- Fixed-Segment Fixed-Bandwidth Schemes --- p.6Chapter 2.2 --- Variable-Segment Fixed-Bandwidth Schemes --- p.7Chapter 2.3 --- Fixed-Segment Variable-Bandwidth Schemes --- p.8Chapter 2.4 --- Variable-Segment Variable-Bandwidth Schemes --- p.9Chapter 2.5 --- Performance Bounds of Periodic Broadcastings --- p.10Chapter Chapter 3 --- Consonant Broadcasting --- p.12Chapter 3.1 --- Type-I Channels --- p.14Chapter 3.2 --- Type-II Channels --- p.15Chapter 3.3 --- Client Buffer --- p.17Chapter Chapter 4 --- Performance Evaluation --- p.19Chapter 4.1 --- Startup Latency versus Network Bandwidth --- p.20Chapter 4.2 --- Startup Latency versus Client Access Bandwidth --- p.22Chapter 4.3 --- Client Buffer Requirement --- p.24Chapter Chapter 5 --- Grouped Consonant Broadcasting --- p.25Chapter 5.1 --- Bandwidth Partitioning and Reception Schedule --- p.26Chapter 5.2 --- Client Buffer Requirement --- p.28Chapter 5.3 --- Performance Tradeoffs --- p.30Chapter Chapter 6 --- Implementation and Benchmarking --- p.34Chapter 6.1 --- Practical Issues --- p.35Chapter 6.2 --- Experimental Results --- p.36Chapter Chapter 7 --- Dynamic Consonant Broadcasting --- p.39Chapter 7.1 --- Virtual Transmission Schedules --- p.40Chapter 7.2 --- Dynamic Broadcasting Schedules --- p.42Chapter 7.3 --- Performance Evaluation --- p.44Chapter Chapter 8 --- Variable-bit-rate Video Streaming --- p.46Chapter 8.1 --- Transmission Schedules --- p.46Chapter 8.2 --- Playback Continuity --- p.48Chapter 8.3 --- Performance Evaluation --- p.50Chapter Chapter 9 --- Conclusions --- p.53Bibliography --- p.5

Rate Aware Instantly Decodable Network Codes

This paper addresses the problem of reducing the delivery time of data messages to cellular users using instantly decodable network coding (IDNC) with physical-layer rate awareness. While most of the existing literature on IDNC does not consider any physical layer complications and abstract the model as equally slotted time for all users, this paper proposes a cross-layer scheme that incorporates the different channel rates of the various users in the decision process of both the transmitted message combinations and the rates with which they are transmitted. The consideration of asymmetric rates for receivers reflects more practical application scenarios and introduces a new trade-off between the choice of coding combinations for various receivers and the broadcasting rate for achieving shorter completion time. The completion time minimization problem in such scenario is first shown to be intractable. The problem is, thus, approximated by reducing, at each transmission, the increase of an anticipated version of the completion time. The paper solves the problem by formulating it as a maximum weight clique problem over a newly designed rate aware IDNC (RA-IDNC) graph. The highest weight clique in the created graph being potentially not unique, the paper further suggests a multi-layer version of the proposed solution to improve the obtained results from the employed completion time approximation. Simulation results indicate that the cross-layer design largely outperforms the uncoded transmissions strategies and the classical IDNC scheme