Unequal Loss Protection Research Articles

VE-CoAP: A constrained application layer protocol for IoT video transmission

Regarding the advantages of video for communications, it is expected that video transmission becomes an inseparable part of most IoT solutions which raises numerous challenges especially over LLNs (Low Power Lossy Networks). Considering these challenges and video transmission requirements for IoT applications, utilizing a proper application layer protocol plays an important role consequently. In this paper, a new application layer protocol for IoT video transmission scenarios, named VE-CoAP is proposed. VE-CoAP, which is an extended version of CoAP, develops complementary methods for improving CoAP performance and overcoming its challenges for video transmission scenarios especially over IoT and LLNs. These methods include pushing data from server to client, supporting parallel flows for data transmission as well as preserving video quality with a combination of guaranteed and best-effort transmission and also a ULP (Unequal Loss Protection) method for prioritizing data partitioned H.264 video sequence. To compare the performance of VE-CoAP to CoAP and HTTP, an evaluation considering metrics such as PSNR, SSIM and video delivery duration is performed. The evaluation shows that VE-CoAP outperforms its rivals for burst data transmission in both lossy or low loss networks and it also preserves video quality at a superior level compared to other protocols over LLNs.

Unequal loss protection scheme using a quality prediction model in a Wi-Fi broadcasting system

Wireless local area network–based broadcasting techniques are a type of mobile Internet Protocol television technology that simultaneously transmits multimedia content to local users. Contrary to the existing wireless local area network–based multimedia transmission systems, which transmit multimedia data to users using unicast packets, a wireless local area network–based broadcasting system is able to transmit multimedia data to many users in a single broadcast packet. Consequently, network resources do not increase with the increase in the number of users. However, IEEE 802.11 does not provide a packet loss recovery algorithm for broadcast packet loss, which is unavoidable. Therefore, the forward error correction technique is required to address the issue of broadcast packet loss. The broadcast packet loss rate of a wireless local area network–based broadcasting system that transmits compressed multimedia data is not proportional to the quality deterioration of the received video signals; therefore, it is difficult to predict the quality of the received video while also considering the effect of broadcast packet loss. In this scenario, allocating equal forward error correction packets to compressed frames is not an effective method for recovering broadcast packet loss. Thus, several studies on unequal loss protection have been conducted. This study proposes an effective, prediction-based unequal loss protection algorithm that can be applied to wireless local area network–based broadcasting systems. The proposed unequal loss protection algorithm adopts a novel approach by adding forward error correction packets to every transmission frame while considering frame loss. This algorithm was used as a new metric to predict video quality deterioration, and an unequal loss protection structure was designed, implemented, and verified. The effectiveness of the quality deterioration model and the validity of the unequal loss protection algorithm were demonstrated through experiments.

Unequal Loss Protection Using Layer-Based Recovery Rate (ULP-LRR) for Robust Scalable Video Streaming over Wireless Networks

Scalable video streaming over wireless networks has many challenges. The most significant challenge is related to packet loss. To overcome this problem, in this paper, we propose an unequal loss protection (ULP) method using a new forward error correction (FEC) mechanism for robust scalable video streaming over wireless networks. For an efficient FEC assignment considering video quality, we first introduce a simple and efficient performance metric, the layer-based recovery rate (LRR), for quantifying the unequal error propagation effects of the temporal and quality layers on the basis of packet losses. LRR is based on the unequal importance in both the temporal and the quality layers of a hierarchical scalable video coding structure. Then, the proposed ULP-LRR method assigns an appropriate number of FEC packets on the basis of the LRR to protect the video layers against packet lossy network environments. Compared with conventional ULP algorithms, the proposed ULP-LRR algorithm demonstrates a higher performance for various error-prone wireless channel statuses.

Energy-Minimized Multipath Video Transport to Mobile Devices in Heterogeneous Wireless Networks

The technological evolutions in wireless communication systems prompt the bandwidth aggregation (e.g., Wi-Fi and LTE radio interfaces) for concurrent video transmission to hand-held devices. However, multipath video transport to the battery-limited mobile terminals is confronted with challenging technical problems: 1) high-quality real-time video streaming is throughput-demanding and delay-sensitive; 2) mobile device energy and video quality are not adequately considered in conventional multipath protocols; and 3) wireless networks are error-prone and bandwidth-limited. To enable the energy-efficient and quality-guaranteed live video streaming over heterogeneous wireless access networks, this paper proposes an energy-video aware multipath transport protocol (EVIS). First, we present a mathematical framework to analyze the frame-level energy-quality tradeoff for delay-constrained multihomed video communication over multiple communication paths. Second, we develop scheduling algorithms for prioritized frame scheduling and unequal loss protection to achieve target video quality with minimum device energy consumption. EVIS is able to effectively leverage video frame priority and rateless Raptor coding to jointly optimize energy efficiency and perceived quality. We conduct performance evaluation through extensive emulations in Exata involving real-time H.264 video streaming. Emulation results demonstrate that EVIS advances the state-of-the-art with remarkable improvements in energy conservation, video peak signal-to-noise ratio (PSNR), end-to-end delay, and goodput.

A Degree Distribution Optimization Algorithm in Unequal-Protected LT Code

LT code is the first practical implementation of digital fountain code. The coding behavior of LT code is mainly decided by the degree distribution which determines the relationship between source data and codeword. Since coding systems with unequal loss protection are widely applied, a degree distribution optimization algorithm is designed for unequal-protected LT code. The degree distribution that minimizes the number of un-recovered source symbols is found. By introducing the weighted cost, the optimal degree distribution can be solved by evolutionary strategy. The experimental results are quite promising. Compared with LT code with robust soliton distribution, the proposed algorithm improves the number of the recovered symbols obviously with the same overhead.

Robust vehicle-to-infrastructure video transmission for road surveillance applications

IEEE 802.11p vehicle-to-vehicle and vehicle-to-infrastructure communication technology is currently an emerging research topic in both industry and academia. Respective spectrum allocation of 10-MHz channels in the 5.9-GHz band in the United States and Europe allows considering intervehicle transmission of live-video information as a basis, which enables a new class of safety and infotainment automotive applications such as road video surveillance. This paper is first of its kind where such a video transmission system is developed and experimentally validated. We propose a low-complexity unequal packet loss protection and rate control algorithms for scalable video coding based on the 3-D discrete wavelet transform. We show that in comparison with a scalable extension of the H.264/AVC standard, the new codec is less sensitive to packet losses, has less computational complexity, and provides comparable performance in case of unequal packet loss protection. It is specially designed to cope with severe channel fading typical for dynamic vehicular environments and has low complexity, making it a feasible solution for real-time automotive surveillance applications. Extensive measurements obtained in realistic city traffic scenarios demonstrate that good visual quality and continuous playback is possible when the moving vehicle is in the radius of 600 m from the roadside unit.

Unequal Loss Protection using Playable Frame Rate of Scalable Video

본 논문은 스케일러블 비디오의 스트리밍 전송 품질 향상을 위해서, 순방향 오류 정정(forward error correction, FEC) 메커니즘을 이용한 비대칭 손실 보호(unequal loss protection, ULP) 알고리즘을 제안한다. 제안된 ULP 알고리즘은 스케일러블 비디오의 계층적 압축구조의 시간과 화질 계층에 존재하는 비대칭의 중요도를 이용한다. 효과적인 FEC 패킷의 할당을 위해서, 제안된 ULP 알고리즘은 낮은 복잡도의 효과적인 성능 메트릭인 프레임 재생율(playable frame rate, PFR)을 유도한다. PFR을 FEC 패킷으로부터 시간과 화질 계층에 존재하는 비대칭의 블록 복원율을 정량화하기 위해서 사용된다. 기존의 다른 알고리즘과 비교하여, 제안된 알고리즘은 다양한 채널 상황에서 더 높은 PSNR 값을 얻을 수 있었다.

Unequal Loss Protection for H.264/AVC Video Streaming Over Wireless Networks

An efficient unequal loss protection (ULP) scheme for robust delivery of pre-encoded video with data partitioning over packet-lossy wireless networks is presented. The proposed scheme employs forward error correction (FEC) across packets to cope with the unreliable situations of the channel. To optimally allocate FEC codes for the different partitions packets of the different frames in one group of pictures (GOP), the overall expected distortion over one GOP is developed as the performance metric to guide the optimization process. In addition, a low-complexity FEC allocation algorithm is also proposed. Experimental results demonstrate that, compared with the other loss protection schemes, the proposed scheme achieves better reconstructed video quality.

Rate-distortion optimized unequal loss protection for video transmission over packet erasure channels

Video transmission over networks often suffers from packet loss due to network congestions and stringent end-to-end delay constraints. In this paper, we develop a Rate-Distortion optimized Unequal Loss Protection (RD-ULP) scheme to combat packet loss. Based on packet-level transmission distortion modeling, we estimate the amount of contribution of each video packet to the reconstructed video quality, which defines the priority level of each packet. Unequal amounts of protection are then allocated to different video packets according to their priority levels and the dynamic channel conditions. The proposed RD-ULP resource allocation problem is formulated as a constrained nonlinear optimization problem. An optimization algorithm based on Particle Swarm Optimization (PSO) is then developed to solve the optimal resource allocation problem. Our extensive experimental results demonstrate the effectiveness of the proposed RD-ULP scheme, which outperforms existing methods by up to 2dB in the reconstructed video quality.

Cross layer design for equal and unequal loss protection frameworks in cognitive radio networks

This study addresses the reliability of secondary multimedia transmissions under delay constraints and lossy conditions. In particular, a cognitive radio (CR) infrastructure collocated with a licensed network is considered. The primary traffic evolves following a Poisson distribution. During the sensing operations, the best spectrum opportunities are identified using a new subchannel quality metric. To mitigate the effects of packet loss, the use of a multiple description coding (MDC) framework of the unequal loss protection (ULP) class is explored. The performance of the proposed scheme is evaluated by comparing the results with those of the traditional equal loss protection (ELP) technique. Finally, a general cross layer model is proposed to ensure end-to-end message delivery in realistic cognitive radio contexts, which are characterized by difficult primary signal detection and random primary interruptions, in addition to subchannel impairments. Numerical simulations are conducted to investigate the peak signal-to-noise ratio (PSNR) benefits of the proposed system using both ULP and ELP schemes.

A Quality Ratio-Based Novel Unequal Loss Protection Scheme in Wi-Fi Broadcasting System

 Abstract—The Wi-Fi broadcast system using the broadcast packet transmits the multimedia contents to many local mobile users in real time and it must use the FEC technology to recover the broadcast packet loss, because Media Access Control layer retransmission is not supported for broadcast packet loss. Equally adding the redundant packet is not very efficient due to the nature of the multimedia data. So, several studies have been made on the Unequal Loss Protection (ULP). Proposed ULP system can efficiently add the redundant packet to the source video data with experimentally modeling the deterioration of video according to the broadcast packet loss in Wi-Fi based broadcasting system. In order to predict the video deterioration, we use the Expected Quality Ratio (EQR). It is a ratio of the video deterioration of compression to the video deterioration of packet loss. And, we design the framework of ULP system to predict the video quality using the EQR. We implement and experiment the proposed algorithm. Experiment results show how our algorithm outperforms other recovery methods of packet loss.

Joint Redundant and Random Network Coding for Robust Video Transmission over Lossy Networks

In this paper a novel unequal packet loss protection scheme R2NC based on low-triangular global coding matrix with ladder-shaped partition is presented, which combines redundant and random network coding for robust H.264/SVC video transmission. Firstly, the error-correcting capabilities of redundant network coding make our scheme resilient to loss. Secondly, the implementation of random network coding at the intermediate nodes with multiple input links can reduce the cost of network bandwidth, thus reducing the end-to-end delay for video transmission. Thirdly, the low-triangular global coding matrix with ladder-shaped partition is maintained throughout the R2NC processes to reduce the impact of global coding matrix's rank deficiency on video transmission and provide unequal erasure protection for H.264/SVC priority layers. The redundant network coding avoids the retransmission of lost packets and improves error-correcting capabilities of lost packets. Based only on the knowledge of the packet loss rates on the output links, the source node and intermediate nodes can make decisions for redundant network coding and random network coding (i.e., how much redundancy to add at this node). However, the redundancy caused by redundant network coding makes the network load increases. In order to improve network throughput, we performed random network coding at the intermediate nodes. Our approach is grounded on the overall distortion of reconstructed video minimization by optimizing the amount of redundancy assigned to each layer. The convex optimization model is constructed under the constraint of network coding and scalable video coding. Experimental results are shown to demonstrate the significant improvement of H.264/SVC video reconstruction quality with R2NC over packet lossy networks.

Multiple description coding of scalable video stream based on unequal loss protection and optimal rate allocation

Forward Error Correction (FEC) codes may be used to protect a video code stream against packet erasures or errors when passing through an error-prone network. To have maximum possible fidelity at the decoder side, an Unequal Loss Protection (ULP) approach should be used to packetize the scalable video code stream, so that the different parts of the scalable video stream are protected according to their importance. Unequal loss-protected packetization leads to segmentation of the scalable code stream, such that the source can be reconstructed with the maximum possible fidelity at the decoder side. In Ardestani et al. (2009) [1] we have found an analytical relation between the optimal sizes of any two consecutive segments. This idea yields an efficient (as efficient as the local search algorithm in Stankovic et al. (2002) [2]) low-complexity progressive solution for the segmentation problem. In this paper, we use a progressive approach for ULP packetization of a scalable video stream generated from a T+2D encoder. In addition, an optimal rate allocation is used for optimal rate budget division between successive Groups Of Pictures (GOPs) of the video sequence. The experimental results demonstrate that the optimal rate budget allocation outperforms the conventional strategy of equal rate budget distribution up to 0.65 dB.

A video-aware FEC-based unequal loss protection system for video streaming over RTP

A video-aware unequal loss protection (ULP) system for protecting RTP video streaming in bursty packet loss networks is proposed. Considering the relevance of the frame, the state of the channel, and the bitrate constraints of the protection bitstream, our algorithm selects in real time the most suitable frames to be protected through forward error protection (FEC) techniques. It benefits from a wise RTP encapsulation that allows working at a frame level without requiring any further process than that of parsing RTP headers. This makes our system straightforward and fast, perfectly suitable to be included in commercial video streaming servers. Simulation results show how our technique outperforms other proposed ULP schemes.

Perceptually Unequal Packet Loss Protection by Weighting Saliency and Error Propagation

We describe a method for achieving perceptually minimal video distortion over packet-erasure networks using perceptually unequal loss protection (PULP). There are two main ingredients in the algorithm. First, a perceptual weighting scheme is employed wherein the compressed video is weighted as a function of the nonuniform distribution of retinal photoreceptors. Secondly, packets are assigned temporal importance within each group of pictures (GOP), recognizing that the severity of error propagation increases with elapsed time within a GOP. Using both frame-level perceptual importance and GOP-level hierarchical importance, the PULP algorithm seeks efficient forward error correction assignment that balances efficiency and fairness by controlling the size of identified salient region(s) relative to the channel state. PULP demonstrates robust performance and significantly improved subjective and objective visual quality in the face of burst packet losses.

Image and video transmission: a comparison study of using unequal loss protection and multiple description coding

We present a performance comparison between multiple description coding (MDC) and unequal loss protection (ULP) as tools to deliver multimedia data to mobile users. Graceful-degradation encoding schemes are able to cope with packet losses due to time-variant channels as they allow the receivers to partially reconstruct the transmitted data with only a subset of received packets. We address a rate-distortion-based multiple description coding scheme and a state-of-the-art unequal loss protection algorithm based on Reed Solomon Forward Error Correction (FEC) codes. The comparison is performed using as a case study JPEG 2000 coded images and H.264/AVC video sequences transmitted over lossy packet networks. Complexity aspects are also considered. The simulation results show that both schemes allocate the same amount of redundancy for any given encoding output rate to protect the transmitted information. The main findings are that MDC, besides being computationally less intensive, achieves a smoother performance degradation, whereas, the ULP scheme yields superior performance in terms of the expected PSNR.

Joint Decoding of Unequally Protected JPEG2000 Bitstreams and Reed-Solomon Codes

In this paper we present joint decoding of JPEG2000 bitstreams and Reed-Solomon codes in the context of unequal loss protection. Using error resilience features of JPEG2000 bitstreams, the joint decoder helps to restore the erased symbols when the Reed-Solomon decoder fails to retrieve them on its own. However, the joint decoding process might become time-consuming due to a search through the set of possible erased symbols. We propose the use of smaller codeblocks and transmission of a relatively small amount of side information with high reliability as two approaches to accelerate the joint decoding process. The accelerated joint decoder can deliver essentially the same quality enhancement as the nonaccelerated one, while operating several times faster.

Sliding-Window Raptor Codes for Efficient Scalable Wireless Video Broadcasting With Unequal Loss Protection

Digital fountain codes have emerged as a low-complexity alternative to Reed-Solomon codes for erasure correction. The applications of these codes are relevant especially in the field of wireless video, where low encoding and decoding complexity is crucial. In this paper, we introduce a new class of digital fountain codes based on a sliding-window approach applied to Raptor codes. These codes have several properties useful for video applications, and provide better performance than classical digital fountains. Then, we propose an application of sliding-window Raptor codes to wireless video broadcasting using scalable video coding. The rates of the base and enhancement layers, as well as the number of coded packets generated for each layer, are optimized so as to yield the best possible expected quality at the receiver side, and providing unequal loss protection to the different layers according to their importance. The proposed system has been validated in a UMTS broadcast scenario, showing that it improves the end-to-end quality, and is robust towards fluctuations in the packet loss rate.

A Comparison Between ULP and MDC With Many Descriptions for Image Transmission

In this letter, we present a performance comparison between multiple description coding (MDC) and unequal loss protection (ULP) for progressive image transmission over lossy packet networks. Two optimization criteria are considered, i.e., a multi-quality criterion, when N distinct quality levels are guaranteed at the decoder side, and the optimization of the expected quality at the receiver. We resort to both a semi-analytical approach and simulation results. To enable numerical comparisons, we address a specific MDC algorithm suitable for progressive imaging, and a state-of-the-art ULP algorithm based on Reed Solomon codes. The results, although cannot be generalized to any MDC and ULP methods, are useful to put into evidence some general features that can drive the selection of the most proper technique for the application at hand. In fact, they allow to put into evidence the main advantages and drawbacks of either technique.

Distortion-Minimized Video Slicing for Unequal Loss Protection

This letter proposes a distortion-minimized slicing scheme for the unequal loss protection of compressed video bitstreams transported over packet networks. Unlike most existing slicing methods where each slice includes nearly equal number of video macroblocks, the proposed scheme reorders the macroblocks in one video frame according to their importance, and then divides them into two slices with an unequal proportion. According to given channel conditions and a novel unequal loss protection scheme, the more appropriate macroblock division ratio can be found out to achieve minimized end-to-end distortion. Simulation results show that the proposed slicing scheme outperforms state-of-the-art approaches with fixed macroblock division ratio.