Doug Young Suh

Improved Anti-collision Scheme for High Speed Identification in RFID System

Tag identification time is handled as an important factor because the performance of RFID system is decided by this factor dominantly. To improve this ability, many anti-collision algorithms have been applied on RFID system. ALOHA based anti-collision algorithms are simple and they have superior anti-collision ability. But, it has disadvantage that the identification performance grows worse as the collision probability increases rapidly in case the reader recognize multiple tags. The improved framed slotted ALOHA is proposed to solve this problem. The collision probability is reduced and the tag identification speed increases with the proposed method. By the result, the proposed method offers the more efficient identification rate than that of the typical ALOHA method

Bit-plane-based lossless depth-map coding

This work proposes an efficient bit-plane-based lossless depth-map coding method for an MPEG 3-D video coding scheme. This method uses the distinctive image characteristics between bit planes of the depth map. In the simulations, the performances of the proposed coding method are compared with those of the conventional lossless coding methods, i.e., JPEG-LS, JPEG-2000, and H.264/AVC, in terms of the intra- and also intercoding modes. In intracoding mode, the proposed method achieves the highest compression ratios as 14.28:1 on average. JPEG-LS, JPEG2000, H.264/AVC (CAVLC), and H.264/AVC (CABAC) obtain the compression ratios as 9.74:1, 7.68:1, 9.13:1, and 10.97:1, respectively. In intercoding mode, the proposed method also accomplishes the highest compression ratios as 28.91:1 on average. However, H.264/AVC (CAVLC) and H.264/AVC (CABAC) obtain the compression ratios as 19.82:1 and 23.45:1, respectively.

Efficient stereoscopic contents file format on the basis of ISO base media file format

A lot of 3D contents haven been widely used for multimedia services, however, real 3D video contents have been adopted for a limited applications such as a specially designed 3D cinema. This is because of the difficulty of capturing real 3D video contents and the limitation of display devices available in a market. However, diverse types of display devices for stereoscopic video contents for real 3D video contents have been recently released in a market. Especially, a mobile phone with a stereoscopic camera has been released in a market, which provides a user as a consumer to have more realistic experiences without glasses, and also, as a content creator to take stereoscopic images or record the stereoscopic video contents. However, a user can only store and display these acquired stereoscopic contents with his/her own devices due to the non-existence of a common file format for these contents. This limitation causes a user not share his/her contents with any other users, which makes it difficult the relevant market to stereoscopic contents is getting expanded. Therefore, this paper proposes the common file format on the basis of ISO base media file format for stereoscopic contents, which enables users to store and exchange pure stereoscopic contents. This technology is also currently under development for an international standard of MPEG as being called as a stereoscopic video application format.

Delivery of ATSC 3.0 Services With MPEG Media Transport Standard Considering Redistribution in MPEG-2 TS Format

MPEG-2 transport stream (TS), standardized by the ISO/IEC as part of the well-known MPEG-2 standards family, is the most widely deployed standard for multimedia services in traditional broadcast industry, such as ATSC and DVB-T. MPEG standards have been designed to specify essential features for multimedia broadcast applications, such as the structure of multimedia content composed of multiple audio-visual streams and temporal relationships among those streams. One of the new MPEG standards that was recently developed and published, namely MPEG media transport (MMT), has catered for the emerging convergence of digital broadcasting and the Internet. MMT inherits major advantageous features of MPEG-2 TS and adds advanced and innovative features to support broadcast services in the new converged environment. IP-based broadcast standards, e.g., ATSC 3.0, has gained significant attention by the broadcast industries as IP-based broadcast provides more flexible and enriched multimedia broadcast services to users. The ATSC 3.0 has adopted MMT as its one of media delivery technology to strengthen hybrid delivery of multimedia services which could be consumed on multiple devices simultaneously. This paper discusses the use of MMT in ATSC 3.0 service delivery. Important features of MMT will be described together with their restrictions and extensions that are needed to enable efficient delivery of ATSC 3.0 services.

Resource Optimization Scheme for Multimedia-Enabled Wireless Mesh Networks

Wireless mesh networking is a promising technology that can support numerous multimedia applications. Multimedia applications have stringent quality of service (QoS) requirements, i.e., bandwidth, delay, jitter, and packet loss ratio. Enabling such QoS-demanding applications over wireless mesh networks (WMNs) require QoS provisioning routing protocols that lead to the network resource underutilization problem. Moreover, random topology deployment leads to have some unused network resources. Therefore, resource optimization is one of the most critical design issues in multi-hop, multi-radio WMNs enabled with multimedia applications. Resource optimization has been studied extensively in the literature for wireless Ad Hoc and sensor networks, but existing studies have not considered resource underutilization issues caused by QoS provisioning routing and random topology deployment. Finding a QoS-provisioned path in wireless mesh networks is an NP complete problem. In this paper, we propose a novel Integer Linear Programming (ILP) optimization model to reconstruct the optimal connected mesh backbone topology with a minimum number of links and relay nodes which satisfies the given end-to-end QoS demands for multimedia traffic and identification of extra resources, while maintaining redundancy. We further propose a polynomial time heuristic algorithm called Link and Node Removal Considering Residual Capacity and Traffic Demands (LNR-RCTD). Simulation studies prove that our heuristic algorithm provides near-optimal results and saves about 20% of resources from being wasted by QoS provisioning routing and random topology deployment.

Peer-to-peer scalable video streaming using Raptor code

This paper proposes a method for saving resources of the video distribution server by using peer-to-peer communications. In order to adapt to a time-varying channel, scalable video coding and a fountain code, a Raptor code is used. The Raptor code protects video quality asymmetrically according to the significance of scalable video layers; varying in peer-to-peer networks, as a forward error correction (FEC) method. It is also a more efficient peer-to-peer distribution tool (because of its rateless feature) than conventional erasure recovery FEC such as the Reed Solomon code. The simulation shows that peer-to-peer data exchange between the clients can save the resources of the server.

QoE-Driven Channel Allocation and Handoff Management for Seamless Multimedia in Cognitive 5G Cellular Networks

Cognitive radio (CR) is among the promising solutions for overcoming the spectrum scarcity problem in the forthcoming fifth-generation (5G) cellular networks, whereas mobile stations are expected to support multimode operations to maintain connectivity to various radio access points. However, particularly for multimedia services, because of the time-varying channel capacity, the random arrivals of legacy users, and the on-negligible delay caused by spectrum handoff, it is challenging to achieve seamless streaming leading to minimum quality of experience (QoE) degradation. The objective of this paper is to manage spectrum handoff delays by allocating channels based on the user QoE expectations, minimizing the latency, providing seamless multimedia service, and improving QoE. First, to minimize the handoff delays, we use channel usage statistical information to compute the channel quality. Based on this, the cognitive base station maintains a ranking index of the available channels to facilitate the cognitive mobile stations. Second, to enhance channel utilization, we develop a priority-based channel allocation scheme to assign channels to the mobile stations based on their QoE requirements. Third, to minimize handoff delays, we employ the hidden markov model (HMM) to predict the state of the future time slot. However, due to sensing errors, the scheme proactively performs spectrum sensing and reactively acts handoffs. Fourth, we propose a handoff management technique to overcome the interruptions caused by the handoff. In such a way that, when a handoff is predicted, we use scalable video coding to extract the base layer and transmit it during a certain interval time before handoff occurrence to be shown during handoff delays, hence providing seamless service. Our simulation results highlight the performance gain of the proposed framework in terms of channel utilization and received video quality.

Application driven, AMC-based cross-layer optimization for video service over LTE

In this paper, we propose a cross-layer optimization scheme in which the application layer controls the medium access network (MAC) and physical (PHY) layers in long-term evolution (LTE, from 3rd generation partnership project [3GPP] release 8) to maximize the quality of video streaming services. We demonstrate how to optimize quality using the equi-signal-to-noise ratio (equi-SNR) from the lower layer and the equi-peak signal-to-noise ratio (equi-PSNR) from the upper layer in the two-dimensional domain, consisting of a bit rate (R) and packet loss ratio (PLR). The proposed approach outperforms the conventional approach, which operates regardless of the application-specific requirements for quality of service (QoS) and quality of experience (QoE) in PHY.

Merge-and-forward: a cooperative multimedia transmissions protocol using RaptorQ codes

Recently, nodes cooperation has emerged as a popular means for improving the quality of multimedia delivery over fifth-generation cellular networks. However, in the conventional relaying scheme such as amplify-and-forward (AaF), there is a higher probability of duplicate packets at the receiver node which affect the decoding probability and consequently deteriorate the quality of multimedia transmission. In this study, the authors propose a cooperative multimedia transmission protocol based on a novel merge-and-forward relaying and the best relay selection (RS) schemes. Their best RS scheme is based on two important parameters: (i) two-hop link distances and (ii) minimum block error rate value. Moreover, to combat the packet loss for enhanced and reliable video delivery, they adopt application layer forward error correction scheme which is based on the most improved and advanced version of fountain codes (i.e. RaptorQ codes). They evaluate the performance of the proposed scheme under different time-sharing scenarios between the direct and best indirect transmission links in terms of decoding failure probability, decoding overhead, peak signal-to-noise ratio, and mean opinion score. Simulation results show that the proposed scheme outperforms the conventional AaF relaying scheme.

PAD-MAC: Primary User Activity-Aware Distributed MAC for Multi-Channel Cognitive Radio Networks

Cognitive radio (CR) has emerged as a promising technology to solve problems related to spectrum scarcity and provides a ubiquitous wireless access environment. CR-enabled secondary users (SUs) exploit spectrum white spaces opportunistically and immediately vacate the acquired licensed channels as primary users (PUs) arrive. Accessing the licensed channels without the prior knowledge of PU traffic patterns causes severe throughput degradation due to excessive channel switching and PU-to-SU collisions. Therefore, it is significantly important to design a PU activity-aware medium access control (MAC) protocol for cognitive radio networks (CRNs). In this paper, we first propose a licensed channel usage pattern identification scheme, based on a two-state Markov model, and then estimate the future idle slots using previous observations of the channels. Furthermore, based on these past observations, we compute the rank of each available licensed channel that gives SU transmission success assessment during the estimated idle slot. Secondly, we propose a PU activity-aware distributed MAC (PAD-MAC) protocol for heterogeneous multi-channel CRNs that selects the best channel for each SU to enhance its throughput. PAD-MAC controls SU activities by allowing them to exploit the licensed channels only for the duration of estimated idle slots and enables predictive and fast channel switching. To evaluate the performance of the proposed PAD-MAC, we compare it with the distributed QoS-aware MAC (QC-MAC) and listen-before-talk MAC schemes. Extensive numerical results show the significant improvements of the PAD-MAC in terms of the SU throughput, SU channel switching rate and PU-to-SU collision rate.