Top PDF Unequal Error Protection Raptor Codes

Unequal Error Protection Raptor Codes

Unequal Error Protection Raptor Codes

cycles exist in the Tanner graph. Cycles provide a path through which intrinsic information can travel and reach their corresponding nodes, i.e., the nodes that sent them. Although there exist many procedures to remove cycles from graphs in general or from Tanner graphs in the case of parity-check matrices but most practical codes are suboptimal in the sense that they contain cycles. However, message passing decoding algorithms perform very well for properly designed codes and reach error rates deemed as acceptable for the majority of applications. From the discussion above we can understand the reason to desire Tanner graphs with the largest girth possible.
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A novel unequal error protection scheme for 3-D video transmission over cooperative MIMO-OFDM systems

A novel unequal error protection scheme for 3-D video transmission over cooperative MIMO-OFDM systems

As mentioned earlier, the P-VpD schemes are proposed to reduce the data rate for transmission. The performance of these schemes compared to the D-VpD schemes shown in Figure 12. The results lead to the following observa- tions: although the 3-D video streams are protected by LDPC codes, the recovery of the video signal is almost impossible at low SNRs ( − 9 to − 6 dB). This is mainly due to excessive errors in the VLC bitstreams that cause severe error propagation. In this case, to overcome the error propagation effect, the video data requires high protection with the high data rate which lead to increase the com- plexity of the channel encoding and decoding operations. Therefore, the Switch-1 and Switch-2 as shown in Figure 1 switch to the D-VpD-UEP scheme at low SNRs, while they switch to P-VpD-UEP and D-VpD-EEP at moderate and high SNRs, respectively, to overcome this problem. This adaptive technique enhances the video system to display the 3-D video signal at low SNRs. Furthermore, it reduces the complexity of the encoding and decoding operations as well as the required data rates at moderate- to-high SNRs. In addition, the proposed technique adopts different VpD schemes that make it more flexible to achieve high 3-D video quality with low required data rates. The selection between these schemes depends on the required video quality and the complexity of the video system. Thus, the D-VpD schemes represent a restricted design between right (color) and depth sequences for the UEP scheme, while the P-VpD schemes make the 3-D video system flexible to determine the more impor- tant and less important information inside the color and depth sequences.
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Unequal error protection for data partitioned H.264/AVC video broadcasting

Unequal error protection for data partitioned H.264/AVC video broadcasting

Multimedia broadcasting over wireless networks is rapidly increasing. Since wire- less channels are prone to errors and packet losses, error mitigation measures must be incorporated. Forward Error Correction (FEC) is the favored approach as retrans- missions in broadcasting applications are usually counter-productive [1], [2]. Indeed, FEC codes are successfully applied in Digital Video Broadcast (DVB) networks. For example, DVB-Handheld (DVB-H) specifies a Multi-Protocol Encapsulation - FEC (MPE-FEC) solution at the link layer designed for real-time services [3], which ap- plies adaptive punctured Reed-Solomon (RS) codes against packet losses. The DVB- H standard also provides a possibility of using Application Layer (AL) FEC solution for Internet Protocol (IP) datacasting services using a well-known class of rateless codes called Digital Fountain (DF) Raptor codes [2], [4]. Though DF Raptor codes are currently used only for non real-time services, they have been investigated for multi-burst protection and compared to MPE-FEC in terms of performance and delay for real-time services over DVB-H [5] and DVB-NGH (Next Generation Handheld). Apart from DF Raptor codes, a class of rateless codes that have been gaining in- creased popularity recently for applications in wireless networks are Random Linear Codes (RLC) [6], [7]. RLC show near-optimal performance even for very low code- word lengths, but suffer from high decoding complexity of the Gaussian Elimination (GE) decoder as the codeword length increases. However, for real-time video trans- mission, RLC is usually applied over short chunks of video data (called generations) thus working in the domain of practically implementable codeword lengths [8], [9]. In addition, as multihop and cooperative communications are becoming increasingly popular in emerging wireless network architectures, introduction of RLC may serve as a step forward towards exploring the benefits of network coding [6]. In the context of future DVB networks, this may be important for emerging concepts such as hybrid broadcast/cellular networks (with clients equipped with multiple wireless broadband interfaces) and device-to-device communications [10].
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Unequal error protection for power line communications over impulsive noise channels

Unequal error protection for power line communications over impulsive noise channels

The main problem with PLC is its noise which is not the simple AWGN model [ 17 ]. A lot of work has been done to model the noise over power lines. This can be divided into narrow-band PLC noise models, e.g. [ 15 , 16 ], and wide-band PLC noise models, e.g. [ 12 ]. Broadband PLC with impulsive noise was studied in [ 18 ] but for a single priority level of data. On the other hand, little work has been done on unequal error protection (UEP) techniques for PLC, e.g. [ 19 ], which considered a different noise model from our model, and focused on video transmission. In [ 20 ], UEP was implemented through LDPC codes. In this work, we consider the problem of UEP over impulsive noise channels for PLC. Closed-form expressions for the error probability are derived for hierarchical 4/16 QAM system in impulsive noise for single carrier and OFDM cases. Based on those, a bit loading algorithm is developed to provide UEP for this PLC system. Improvement due to our bit loading algorithm is demonstrated. Analytical results are presented together with simulations.
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A New Unequal Error Protection Technique Based on the Mutual Information of the MPEG-4 Video Frames over Wireless Networks

A New Unequal Error Protection Technique Based on the Mutual Information of the MPEG-4 Video Frames over Wireless Networks

Abstract: The performance of video transmission over wireless channels is limited by the channel noise. Thus many error resilience tools have been incorporated into the MPEG-4 video compression method. In addition to these tools, the unequal error protection (UEP) technique has been proposed to protect the different parts in an MPEG-4 video packet with different channel coding rates based on the rate compatible punctured convolutional (RCPC) codes. However, it is still not powerful enough for the noisy channels. To provide more robust MPEG-4 video transmission, this paper proposes a modified unequal error protection technique based on the mutual information of two video frames. In the proposed technique, the dynamic channel coder rates are determined online based on the mutual information of two consecutive video frames. With this technique, irregular and high motion areas that are more sensitive to errors can get more protection. Simulation results show that the proposed technique enhances both subjective visual quality and average peak signal to noise ratio (PSNR) about 2.5 dB, comparing to the traditional UEP method.
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Rate-Distortion Optimization for Stereoscopic Video Streaming with Unequal Error Protection

Rate-Distortion Optimization for Stereoscopic Video Streaming with Unequal Error Protection

A novel technique that recently becomes popular for error protection in lossy packet networks is Fountain codes, also called rateless codes. The Fountain coding idea is proposed in [13] and followed by practical realizations such as LT codes [14], online codes [15], and Raptor codes [16]. Following the practical realizations, Fountain codes have gained attention in video streaming in recent years [17–19]. The main idea behind Fountain coding is to produce as many parity packets as needed on the fly. This approach is different from the general idea of FEC codes where channel encoding is performed for a fixed channel rate and all encoded packets are generated prior to transmission. The idea is proven to be e ffi cient in [14] for large source data sizes, as in the case of video data, and it does not utilize retransmissions.
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Turbo Detected Unequal Error Protection Irregular Convolutional Codes Designed for the Wideband Advanced Multirate Speech Codec

Turbo Detected Unequal Error Protection Irregular Convolutional Codes Designed for the Wideband Advanced Multirate Speech Codec

The novel contribution of the paper is that UEP and EXIT chart based code optimization can be jointly carried out and successfully applied to robust speech transmission. We propose a serially con- catenated turbo transceiver using an IRCC as the outer code for the transmission of Adaptive Multi-Rate Wideband (AMR-WB) coded speech. Rather than being decoded separately, the constituent codes of the IRCC are decoded jointly and iteratively by exchanging extrinsic information with the inner code. The IRCC is optimized to match the characteristics of both the speech source codec and those of the channel, so that UEP is achieved while maximizing the iteration gain attained.
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Content Based Image Unequal Error Protection Strategies for an Open Loop MIMO System

Content Based Image Unequal Error Protection Strategies for an Open Loop MIMO System

The paper deals with strategies for optimizing the transmission of JPEG2000 coded images over a MIMO quasi-static Rayleigh fading channel, by exploiting different available MIMO STBC (Space Time Block Codes), as well as the im- age content to be transmitted. The aim is to propose a link adaptation scheme based on the variable radio channel’s conditions, by establishing an UEP (Unequal Error Protection) scheme that leads to the best tradeoff between the ro- bustness to errors and the image visual quality. Comparisons are made with the EEP (Equal Error Protection) case, in terms of the PSNR (Peak Signal to Noise Ratio) fidelity metric, as well as the subjective image quality.
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Multi-user video streaming using unequal error protection network coding in wireless networks

Multi-user video streaming using unequal error protection network coding in wireless networks

unlike routing, it achieves the capacity of the multicast connection [3]. For the single-source multicast problems represented by directed acyclic graphs with unit-capacity error-free edges, the class of linear network codes achieves the multicast connection capacity [4]. Furthermore, ran- dom linear codes over sufficiently large finite fields open the way for simple and fully distributed network code design [5]. The random linear coding (RLC) approach is adapted for practical implementation in lossy packet networks [6,7], and suggested in a number of wireless networking applications [8,9].
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A novel unequal error protection scheme for 3-D video transmission over cooperative MIMO-OFDM systems

A novel unequal error protection scheme for 3-D video transmission over cooperative MIMO-OFDM systems

As mentioned earlier, the P-VpD schemes are proposed to reduce the data rate for transmission. The performance of these schemes compared to the D-VpD schemes shown in Figure 12. The results lead to the following observa- tions: although the 3-D video streams are protected by LDPC codes, the recovery of the video signal is almost impossible at low SNRs ( − 9 to − 6 dB). This is mainly due to excessive errors in the VLC bitstreams that cause severe error propagation. In this case, to overcome the error propagation effect, the video data requires high protection with the high data rate which lead to increase the com- plexity of the channel encoding and decoding operations. Therefore, the Switch-1 and Switch-2 as shown in Figure 1 switch to the D-VpD-UEP scheme at low SNRs, while they switch to P-VpD-UEP and D-VpD-EEP at moderate and high SNRs, respectively, to overcome this problem. This adaptive technique enhances the video system to display the 3-D video signal at low SNRs. Furthermore, it reduces the complexity of the encoding and decoding operations as well as the required data rates at moderate- to-high SNRs. In addition, the proposed technique adopts different VpD schemes that make it more flexible to achieve high 3-D video quality with low required data rates. The selection between these schemes depends on the required video quality and the complexity of the video system. Thus, the D-VpD schemes represent a restricted design between right (color) and depth sequences for the UEP scheme, while the P-VpD schemes make the 3-D video system flexible to determine the more impor- tant and less important information inside the color and depth sequences.
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Robust Transmission of H.264/AVC Streams Using Adaptive Group Slicing and Unequal Error Protection

Robust Transmission of H.264/AVC Streams Using Adaptive Group Slicing and Unequal Error Protection

The scheme proposed in the present paper is based on macroblock classification and unequal error protection of H.264/AVC streams. Prior to transmission, macroblocks are classified into three slice groups by examining their contri- bution to video quality. Since the transmission scenarios are over packet networks, facing moderate to high packet loss rates, RS codes are used for channel protection. RS protection is selected for each slice group using a channel rate alloca- tion algorithm based on dynamic programming techniques. To the best of our knowledge, the present method is the first utilizing the explicit mode of the H.264/AVC flexible mac- roblock ordering (FMO) [13] in conjunction with channel coding techniques. The resulting system is evaluated and is shown to outperform the recently proposed method in [5]. The performance gain is attributed to the more e ffi cient data organization of our scheme, which allows better error con- cealment without sacrificing coding performance, and to the finer protection of slice groups arising from our unequal er- ror protection strategy.
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A novel unequal error protection scheme for 3 D video transmission over cooperative MIMO OFDM systems

A novel unequal error protection scheme for 3 D video transmission over cooperative MIMO OFDM systems

As mentioned earlier, the P-VpD schemes are proposed to reduce the data rate for transmission. The performance of these schemes compared to the D-VpD schemes shown in Figure 12. The results lead to the following observa- tions: although the 3-D video streams are protected by LDPC codes, the recovery of the video signal is almost impossible at low SNRs ( − 9 to − 6 dB). This is mainly due to excessive errors in the VLC bitstreams that cause severe error propagation. In this case, to overcome the error propagation effect, the video data requires high protection with the high data rate which lead to increase the com- plexity of the channel encoding and decoding operations. Therefore, the Switch-1 and Switch-2 as shown in Figure 1 switch to the D-VpD-UEP scheme at low SNRs, while they switch to P-VpD-UEP and D-VpD-EEP at moderate and high SNRs, respectively, to overcome this problem. This adaptive technique enhances the video system to display the 3-D video signal at low SNRs. Furthermore, it reduces the complexity of the encoding and decoding operations as well as the required data rates at moderate- to-high SNRs. In addition, the proposed technique adopts different VpD schemes that make it more flexible to achieve high 3-D video quality with low required data rates. The selection between these schemes depends on the required video quality and the complexity of the video system. Thus, the D-VpD schemes represent a restricted design between right (color) and depth sequences for the UEP scheme, while the P-VpD schemes make the 3-D video system flexible to determine the more impor- tant and less important information inside the color and depth sequences.
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A Multiresolution Channel Decomposition for H 264/AVC Unequal Error Protection

A Multiresolution Channel Decomposition for H 264/AVC Unequal Error Protection

Multiresolution analysis via decomposition is an impor- tant tool in signal analysis. An analogous framework for the multiresolution analysis of finite-length sequences from aritrary field was defined in term of the generator matrices of convolutional code [14]. Convolutional codes are core constituent for turbo coding and can be treated using both the multirate analysis because of their con- volution property and the finite state machine analysis. In this work we will use both analysis for understanding the behavior of multiresolution and decomposition of convo- lutional code and hence the PCCC and the Turbo codes.
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Enhancement of Unequal Error Protection Properties of LDPC Codes

Enhancement of Unequal Error Protection Properties of LDPC Codes

and references therein). In these UEP coding schemes, rate- compatible error correcting schemes are combined with a rate-allocation algorithm to mainly minimize the distortion of the source at the receiver. As the channel code design and UEP allocation algorithm are considered separately, making the design of good rate compatible coding schemes com- pletely independent of the considered CSCC scheme, these coding schemes can be further improved by considering a joint source-channel (de)coding approach (see [7, 8], e.g., in case of LDPC codes). In these approaches, the distortion-rate or mutual information transfer function are directly used for the optimization of the irregularity profiles, and thus, UEP allocation could naturally arise from the optimization pro- cess.
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On the complexity-performance trade-off in soft-decision decoding for unequal error protection block codes

On the complexity-performance trade-off in soft-decision decoding for unequal error protection block codes

AWGN channel. It was verified the performance of both algorithms compared to that of the ML one. The behav- ior of the GC-2 algorithm was investigated for estimating the analog weight (Step 4) according to the variation of its parameters (t and p), while the WED algorithm was examined for a new proposed reliability according to the variation of its parameters (t and Q). To estimate the com- plexity of each algorithm, it was computed the number of arithmetic operations per decoded sequence. An anal- ysis of the trade-off between performance and complexity of the algorithms was performed for each protection class assuming various configuration options. These analyses led us to conclude that, when choosing the parameters of the algorithms, the increase of the error-correcting capa- bility of the binary decoder (t) was more advantageous in both cases. In addition, choosing the values of p and Q such that γ is close to one (for a fixed value of t), it was verified that the GC-2 algorithm is less complex, while the WED algorithm can offer (depending on the code adopted) a performance closer to the ML one.
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Expanding Window Fountain Codes for Unequal Error Protection

Expanding Window Fountain Codes for Unequal Error Protection

The asymptotic degree distributions are derived for each of r different classes of input and output symbols.. The set of output symbol degree distributions is given by the code definitio[r]

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Improved Design of Unequal Error Protection LDPC Codes

Improved Design of Unequal Error Protection LDPC Codes

In this work, we consider the flexible UEP-LDPC code design proposed in [3], which is based on a hierarchical optimization of the variable node degree distribution for each protection class. The algorithm maximizes the average variable node degree within one class at a time while guaran- teeing a minimum variable node degree as high as possible. The optimization can be stated as a linear programming problem and can, thus, be easily solved. To keep the average performance of the UEP-LDPC code reasonably good, the search for UEP codes is limited to degree distributions whose convergence thresholds lie within a certain range of the minimum threshold of a code with the same parameters. In the following, we call the threshold o ff set.
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An Iterative Detection Aided Unequal Error Protection Wavelet Video Scheme Using Irregular Convolutional Codes

An Iterative Detection Aided Unequal Error Protection Wavelet Video Scheme Using Irregular Convolutional Codes

The PSNR performances of both the UEP and EEP system are depicted in Fig. 8. It can be seen that the UEP system attains a near error-free PSNR transmission quality in excess of E b N 0 = 2 . 1 dB. Although at this point the overall BER is about 2 × 10 −3 , the most sensitive video bits protected by the strongest subcodes are almost error-free. The EEP system reaches the same BER at an E b N 0 of about 1.7 dB, but the PSNR attained is significant worse (< 14 dB). It is also worth noting that for the UEP system, the residual BER becomes so low that it has a negligible effect on the PSNR performance.
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Generalized Punctured Convolutional Codes with Unequal Error Protection

Generalized Punctured Convolutional Codes with Unequal Error Protection

When considering the minimal trellis complexity TC( M) in the search criterion several codes which are not listed in the literature can be found. That is because when considering the typical encoder memory order criterion the leaps between available decoding complexity values are very large (the complexity doubles for each additional memory in the encoder). The TC( M)-based criterion allows for an increased granularity in the list of decoding complexity values, as can be seen in Tables 1–5 in the manuscript. Therefore, the proposed criterion and the resultant UEP codes give a much larger flexibility for the system designer.
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Adaptive Modulation and Superposition Coding for MIMO Data Transmission Using Unequal Error Protection and Ordered Successive Interference Cancellation Techniques

Adaptive Modulation and Superposition Coding for MIMO Data Transmission Using Unequal Error Protection and Ordered Successive Interference Cancellation Techniques

obtain a thorough and general understanding of this phenomenon. In this process, the user’s face, which is taken in the foreground, is part of the high-importance (HI) data layer, whereas the background scene reflects the low-importance (LI) data layer “Ref. [1], [2]”. There is a priority to transmit more reliable HI data than LI data, which is one requirement for optimising the quality of service (QoS). Hence, it is more important to protect the HI data than the LI data from being corrupted by the channel. In the last decade, there have been an increasing number of emergent plans or schemes devoted to develop error control schemes in the field of wireless communication. One of these schemes is known as UEP, where the original and initial proposal of this scheme was for single-carrier systems, but there is a potential extension of its use for multi-carrier systems “Ref. [2]”. UEP has the ability to divide the data signal into two or more layers based on priorities. For instance, the HI layer carries more of the data signal and can perform self- decoding to reconstruct the original signal. However, the LI layer carries the data of less importance, which are employed to enhance the signal quality. Because errors in the HI layer have adverse impacts on the quality of the reconstructed signal, it is important to reduce the errors as much as possible. In contrast, errors in the LI layer can be tolerated more. Therefore, the goal of UEP is to protect the HI layer as much as possible to achieve a high-quality signal “Ref. [2], [3]”. The effectiveness of UEP as a method is related to video transmission in error-prone wireless environments. Its effectiveness is attributed to its ability to protect various parts of the video data with various levels of importance. In its basic function, UEP is capable of making changes in the distribution of errors without consuming additional resources. Thus, the more important data suffers from fewer bit errors “Ref. [4]-[6]”.
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