Loss Recovery Scheme Research Articles

DCR: Deterministic Crash Recovery for NAND Flash Storage Systems

NAND flash memory has been widely adopted as the storage medium. As power failure may occur at any time and result in data loss, crash recovery becomes vitally important in NAND flash memory storage systems. Since flash translation layers (FTLs) are used to manage flash memory, the crash recovery problem in NAND flash is how to efficiently and effectively recover FTL metadata with consistency after system crash. In this paper, we present deterministic crash recovery (DCR) that adopts a deterministic approach for crash recovery in NAND flash storage systems. The basic idea is to exploit the determinism of FTLs and reproduce events that happened between the last checkpoint and the crash point during crash recovery. Different from existing approaches that need to scan the whole flash memory chip, DCR can recover the system more efficiently by only checking a limited number of blocks based on deterministic FTL operations. We have implemented DCR in an FTL and compared it with the representative version-based and power loss recovery schemes based on an ARM-based embedded system. Experimental results show that DCR can greatly reduce the recovery time and guarantee the consistency of FTL metadata after recovery.

A Novel Loss Recovery and Tracking Scheme for Maneuvering Target in Hybrid WSNs.

Tracking a mobile target, which aims to timely monitor the invasion of specific target, is one of the most prominent applications in wireless sensor networks (WSNs). Traditional tracking methods in WSNs only based on static sensor nodes (SNs) have several critical problems. For example, to void the loss of mobile target, many SNs must be active to track the target in all possible directions, resulting in excessive energy consumption. Additionally, when entering coverage holes in the monitoring area, the mobile target may be missing and then its state is unknown during this period. To tackle these problems, in this paper, a few mobile sensor nodes (MNs) are introduced to cooperate with SNs to form a hybrid WSN due to their stronger abilities and less constrained energy. Then, we propose a valid target tracking scheme for hybrid WSNs to dynamically schedule the MNs and SNs. Moreover, a novel loss recovery mechanism is proposed to find the lost target and recover the tracking with fewer SNs awakened. Furthermore, to improve the robustness and accuracy of the recovery mechanism, an adaptive unscented Kalman filter (AUKF) algorithm is raised to dynamically adjust the process noise covariance. Simulation results demonstrate that our tracking scheme for maneuvering target in hybrid WSNs can not only track the target effectively even if the target is lost but also maintain an excellent accuracy and robustness with fewer activated nodes.

Software Architecture for Streaming and Packet Loss Recovery Schemes in Road Monitoring Surveillance Camera Control Systems

Background/Objectives: This paper is about software architecture for security system design using surveillance control system. Various challenges are faced in surveillance control systems using monitoring cameras like packet loose, latency, quality of Closed-Circuit Television (CCTV) data, inconsistency and conflict among multiple sources etc. In this paper an attempt is made to solve some of the problems which are faced by surveillance control systems like road monitoring systems. Methods/Statistical analysis: Experimentation setup is proposed for the given software architecture and algorithm is developed for system. The Digital Video (DV) streaming system is a client-server model for the real-time delivery of DV streams over Internet Protocol (IP) networks based on Real-time Transport Protocol (RTP) / Real-time Transport Control Protocol (RTCP) protocol. The system includes two PCs, one at the server side and one at the client side, connected together with a Fast Ethernet LAN. Server has got a fire wire interface for capturing the data. Capturing device is connected to a DV converter (Canopus ADVC 1000) through a composite conversion cable. Converted DV stream is given to the server through IEEE 1394 interface. In the road monitoring systems such architecture is very much needed to recover from packet losses and it will help in reducing road accidents. Findings: In this paper attempt is made to propose the best possible architecture for arranging surveillance camera for getting the best streaming. Packet loss recovery schemes are proposed in the camera control systems which are used for monitoring roads and it can minimize the death rate using these monitoring camera systems. Applications/Improvements: The proposed software architecture is used in packet loss recovery systems of surveillance systems and very useful application for security systems which are used for monitoring road and it can reduce deaths caused due to road accidents.

EVALUATION OF HIDDEN MARKOV MODEL BASED ADAPTIVE PROVISIONING OF OPTICAL BURST SWITCHING NETWORKS AMENABLE FOR UPGRADATION TO GREEN FLEXIGRID NETWORKS

Catering to the evolving bandwidth-on-demand applications requires flexible provisioning architectures that ensure fairness to both high end and low end users of internet. Dynamic classification of network path s into long and short, based on traffic dependent connecti on holding times and a wavelength allocation from different subsets for these categories is a necessi ty for implementing energy saving hybrid switching, loss recovery and flexi grid bit rate variable schemes. Therefore, this study evaluates such a scheme of d ynamic classification based on HMM predicted connection-holding times with tightly integrated adaptive burst sizing and segregated wavelength allocation for lon g and short categories. Simulation study of a 28 no de OBS network shows that this coupled scheme reduces delays and results in throughput improvement of 67% for long and 12% for short traffic over schemes tha t employ adaptive burst sizing based on number of a ctive traffic flows and independent wavelength assignment schemes.

Performance analysis of packet loss recovery policies in P2P video streaming

Packet loss recovery is an important part of P2P video streaming networks due to inevitable packet loss in today's internet and interdependency of data units in compressed video streams. In addition, the architecture of P2P streaming networks, in which the data delivered to the receivers through chain of peers, can intensify the impact of the internet packet loss on the quality of perceived video at the receivers. FEC and ARQ are the two most important techniques that can be used to overcome the side effect of the internet packet loss in P2P video streaming networks. Based on these two techniques, different packet loss recovery strategies can be applied in different overlay hops of a given P2P streaming network. In this paper, we have modelled and analysed the performance and efficiency of variant packet loss recovery policies can be used in P2P streaming networks. Our analysis show that a hybrid packet loss recovery scheme in which the most important data units are protected by packet level FEC and the remaining lost ones are recovered through retransmission i.e., ARQ is the most efficient strategy that improves the performance of P2P video streaming networks.

Hybrid approach for loss recovery mechanism in OBS networks

This letter reports a study of a hybrid burst assembly and a hybrid burst loss recovery scheme (delay-based burst assembly and hybrid loss recovery (DBAHLR)) which selectively employs proactive or reactive loss recovery techniques depending on the classification of traffic into short term and long term, respectively. Traffic prediction and segregation of optical burst switching network flows into the long term and short term are conducted based on predicted link holding times using the hidden Markov model (HMM). The hybrid burst assembly implemented in DBAHLR uses a consecutive average-based burst assembly to handle jitter reduction necessary in real-time applications, with variations in burst sizes due to the non-monotonic nature of the average delay handled by additional burst length thresholding. This dynamic hybrid approach based on HMM prediction provides overall a lower blocking probability and delay and more throughput when compared with forward segment redundancy mechanism or purely HMM prediction-based adaptive burst sizing and wavelength allocation (HMM-TP).

Packet Loss Recovery Scheme with Uniquely-Decodable Codes for Streaming Multimedia over P2P Networks

This paper presents an effective packet loss recovery scheme for Internet Protocol (IP) based peer-to-pear (P2P) networks that deliver multimedia streaming contents. The proposed scheme consists of two key components, a packet forward error correction (FEC) scheme and a uniquely decodable coding (UDC) scheme. The FEC scheme is devised to recover network packet loss over the transport layer to improve link transmission reliability at the user-ends of the P2P networks. The UDC scheme is employed to allow multiple sources to transmit data streams simultaneously in such a way that the combined data streams can be separated uniquely without ambiguity at the user-ends. This simultaneous multiple sources data transmission increases the throughput at the user-ends. Theoretical analysis and computer simulations show that the proposed scheme can achieve the commonly acceptable of 10^{-6} end-to-end packet loss rate for input packet loss rate of up to 10%with a reasonably small bandwidth expansion factor, while maintains a high throughput at the user-ends.

A Loss-Recovery Scheme for Mixed Unicast and Multicast Traffic Using Network Coding

A Loss-Recovery Scheme for Mixed Unicast and Multicast Traffic Using Network Coding

Comparison and optimization of packet loss recovery methods based on AMR-WB for VoIP

AMR-WB codec, which has been standardized for wideband speech conversational applications, has a broad range of potential applications in the migration of wireless and wireline networks towards a single converged IP network. Forward error control (FEC) and multiple description coding (MDC) are two promising techniques to make the transmission robust against packet loss in Voice over IP (VoIP). However, how to achieve the optimal reconstructed speech quality with these methods for AMR-WB under different packet loss rate conditions is still an open problem. In this paper, we compare the performance of various FEC and MDC schemes for the AMR-WB codec both analytically and experimentally. Based on the comparison results, some advantageous configurations of FEC and MDC for the AMR-WB codec are obtained, and hence an optimization system is proposed by selecting the optimal packet loss recovery scheme in accordance with the variable network conditions. Subjective AB test results show that the optimization can lead to obvious improvements of the perceived speech quality in the IP environment.

Network‐coding‐based cache policy for loss recovery enhancement in reliable multicast

SUMMARYIn local loss recovery schemes, a small number of recovery nodes distributed along the transmission paths save incoming packets temporarily in accordance with a specified cache policy and retransmit these packets if they subsequently receive a request message from a downstream receiver. To reduce the recovery latency, the cache policy should ensure that the recovery nodes are always able to satisfy the retransmission requests of the downstream receivers. However, owing to the limited cache size of the recovery nodes and the behavior of the cache policy, this cannot always be achieved, and thus some of the packets must be retransmitted by the sender. Accordingly, this paper develops a new network‐coding‐based cache policy, designated as network‐coding‐based FIFO (NCFIFO), which extends the caching time of the packets at the recovery nodes without dropping any of the incoming packets. As a result, the lost packets can be always recovered from the nearest recovery nodes and the recovery latency is significantly reduced. The loss recovery performance of the NCFIFO cache policy is compared with that of existing cache policies by performing a series of simulation experiments using both a uniform error model and a burst error model. The simulation results show that the NCFIFO cache policy not only achieves a better recovery performance than existing cache policies, but also provides a more effective solution for managing a small amount of cache size in environments characterized by a high packet arrival rate. Copyright © 2011 John Wiley & Sons, Ltd.

Loss Recovery Scheme for TCP Using MAC MIB over Wireless Access Networks

In the wireless network, if the TCP cannot identify the wireless error, it overly reduces the transmission rate by unnecessarily cutting the congestion window down. Therefore, to improve TCP goodput by accurately detecting wireless loss, we propose the MAC MIB based loss recovery scheme that can differentiate between congestion loss and wireless loss without intervention of any intermediate node. The simulation results show that the goodput is substantially enhanced compared to existing schemes in the wireless access network environment, where errors tend to occur in burst due to the intrinsic wireless link characteristics.

XOR-based frame loss recovery scheme for video streaming

High coding dependencies among video frames suffer from vulnerability to packet loss, which impacts the playback quality of video streaming. In this paper, according to the characteristics of MPEG4/H.264 encoding methods, we propose a simple and low-complexity XOR-based FEC frame loss recovery scheme. Within an entire Group of Pictures (GOP), the proposed scheme shows the ability to recover simultaneously I-frame loss and one P-frame loss. The high frame loss resilience improves the playback QoS of compressed video streaming. The mathematical analysis reveals that the proposed scheme has 72.7% performance improvement than no frame loss protection in term of full GOP frames successful decoding rate.

Cooperative Loss Recovery for Reliable Multicast in Ad Hoc Networks

Providing reliable multicast service is very challenging in Ad Hoc networks. In this paper, we propose an efficient loss recovery scheme for reliable multicast (CoreRM). Our basic idea is to apply the notion of cooperative communications to support local loss recovery in multicast. A receiver node experiencing a packet loss tries to recover the lost packet through progressively cooperating with neighboring nodes, upstream nodes or even source node. In order to reduce recovery latency and retransmission overhead, CoreRM caches not only data packets but also the path which could be used for future possible use to expedite the loss recovery process. Both analytical and simulation results reveal that CoreRM significantly improves the reliable multicast performance in terms of delivery ratio, throughput and recovery latency compared with UDP and PGM.

Congestion-aware, loss-resilient bio-monitoring sensor networking for mobile health applications

Many elder patients have multiple health conditions such as heart attacks (of various kinds), brain problems (such as seizure, mental disorder, etc.), high blood pressure, etc. Monitoring those conditions needs different types of sensors for analog signal data acquisition, such as electrocardiogram (ECG) for heart beats, electroencephalogram (EEG) for brain signals, and electromyogram (EMG) for muscles motions. To reduce mobile-health (m-health) cost, the above sensors should be made in tiny size, low memory, and long-term battery operations. We have designed a series of medical sensors with wireless networking capabilities. In this paper, we report our work in three aspects: (1) networked embedded system design, (2) network congestion reduction, and (3) network loss compensation. First, for networked embedded system design, we have designed an integrated wireless sensor network hardware / software platform for multi-condition patient monitoring. Such a system integrates ECG/EEG/other sensors with Radio Frequency Identification (RFID) into a Radio Frequency (RF) board through a programmable interface chip, called PSoc. Second, for network congestion reduction, the interface chip can use compressive signal processing to extract bio-signal feature parameters and only transmit those parameters. This provides an alternative approach to sensor network congestion reduction that aims to alleviate ?hot spot? issues. Third, for network loss compensation, we have designed wireless loss recovery schemes for different situations as follows. (1) If original sensor data streams are transmitted, network congestion will be a big concern due to the heavy traffic. A receiver-only loss prediction will be a good solution. (2) If the signal parameters are transmitted, the transmission loss mandates a 100% recovery rate. We have comprehensively compared the performance of those schemes. The proposed mechanisms for m-health system have potentially significant impacts on today's elder nursing home management and other mobile patient monitoring applications.

A Transparent Loss Recovery Scheme Using Packet Redirection for Wireless Video Transmissions

With the wide deployment of wireless networks and the rapid integration of various emerging networking technologies nowadays, Internet video applications must be updated on a sufficiently timely basis to support high end-to-end quality of service (QoS) levels over heterogeneous infrastructures. However, updating the legacy applications to provide QoS support is both complex and expensive since the video applications must communicate with underlying architectures when carrying out QoS provisioning, and furthermore, should be both aware of and adaptive to variations in the network conditions. Accordingly, this paper presents a transparent loss recovery scheme to transparently support the robust video transmission on behalf of real-time streaming video applications. The proposed scheme includes the following two modules: (i) a transparent QoS mechanism which enables the QoS setup of video applications without the requirement for any modification of the existing legacy applications through its use of an efficient packet redirection scheme; and (ii) an instant frame-level FEC technique which performs online FEC bandwidth allocation within TCP-friendly rate constraints in a frame-by-frame basis to minimize the additional FEC processing delay. The experimental results show that the proposed scheme achieves nearly the same video quality that can be obtained by the optimal frame-level FEC under varying network conditions while maintaining low end-to-end delay.

Video loss recovery with FEC and stream replication

Packet loss is inevitable in video multicast. In this paper, we propose and study an effective feedback-free loss recovery scheme for layered video which combines forward error correction (FEC) and stream replication. In our scheme, the server multicasts the video in parallel with FEC packets and a number of replicated delayed (ReD) version of the stream. Receivers autonomously and dynamically join the FEC and ReD streams to repair their losses. On the server side, we analyze and optimize the number of replicated streams and FEC packets to meet a certain residual loss requirement (i.e., error after correction). On the receiver side, we analyze the optimal combination of FEC and ReD packets to minimize its loss. We also present a fast yet accurate approximation algorithm for receiver to make such decision. We show that FEC combined with merely one or two replicated streams can effectively reduce the residual error rate (by as much as 50%) as compared with pure FEC or replication alone. Both subjective and objective video measures confirm that our recovery scheme achieves much better visual quality.

An efficient and scalable loss-recovery scheme for video multicast

With the increased popularity of multimedia services on the Internet, efficient video multicast strategies that can scale easily are of critical importance. This paper addresses the issue of video multicast loss recovery and presents an efficient and scalable scheme: Active Injection Recovery (AIR). The proposed scheme has three distinguishing features: active injection of repair packets into loss regions, on-demand construction of loss-recovery structures, and unique rate control over repair traffic. All of these features can save considerable network resources in a large-scale video multicast session. In addition, the proposed scheme simultaneously meets the three well-known requirements for efficiency and scalability in multicast loss recovery: request suppression, local recovery, and retransmission scoping. Another important feature of the proposed scheme is its low recovery latency, which is essential for video multicast. Our results show that the proposed scheme achieves significantly better overall performance as compared to existing multicast loss recovery schemes.

Shared packet loss recovery for internet telephony

We consider an Internet telephony system in which the service provider operates a telephone gateway in each servicing city to serve the general public. We propose a shared packet loss recovery scheme for this system. Using this scheme, each gateway uses erasure code to add redundant packets such that its outgoing voice streams share these redundant packets for packet loss recovery. This scheme has two advantages: (1) it has a small probability of packet loss because multiple voice streams can share the redundant packets for effective packet loss recovery, and (2) it involves a small recovery delay because it uses the packets from multiple voice streams for packet loss recovery.

Cache partitioning for multiple sessions in local loss recovery of reliable multicast

Local loss recovery for reliable multicast can provide significant performance improvement in terms of loss recovery latency, bandwidth consumption and network throughput. Active reliable multicast (ARM) is a novel loss recovery scheme for large-scale reliable multicast. In ARM, local loss recovery is realised by retrieving repairs at near active routers. In practice, active resources are limited and active resources allocation strategies are required for optimising performance in terms of the loss recovery and/or network bandwidth consumption. An active router may need to support the local loss recovery for multiple multicast sessions simultaneously. How to partition efficiently the cache resource to these sessions is crucial to the performance of local loss recovery. In the paper, the authors propose a cache partitioning method called ‘layered greedy cache partitioning’ to deal with this dilemma. For this method, the active routers are first grouped into different layers according to the tree topologies and the design begins from the lowest layer. The cache partitioning of an upper layer can be performed separately by making use of relevant design information of the lower layer. An optimisation for cache partitioning at each layer can then be conducted and a ‘local’ optimal solution can be achieved. On a global scale, however, the solution is only suboptimal. The performance of using the proposed cache partitioning method is compared with that using uniform cache partitioning and proportional partitioning. A significant performance improvement is found.

REDUP: a packet loss recovery scheme for real-time audio streaming over wireless IP networks

Due to the characteristics of (1) smaller bandwidth and (2) unreliable transmission media, real-time audio streaming over wireless networks is not trivial. To have smooth audio streaming over wireless networks, we propose a scheme called REDUP in this paper. Two sending modes, in which redundant information is embedded in each packet, that the REDUP scheme contains are (1) the ''redundant'' mode and (2) the ''duplicated'' mode. Let a packet i can contain three audio frames i, i-1, and i-2. In the redundant mode, frame i uses a codec of better quality than that for frames i-1 and i-2. In the duplicated mode, frames i, i-1, and i-2 use the same codec, which has lower quality than that for frame i used in the redundant mode. The ''redundant'' mode may give better quality of sound but consumes more bandwidth, while the ''duplicated'' mode gives lower quality of sound but consumes less bandwidth. The two modes are selected depending on the networking situation. Round trip time (RTT) between the mobile host and the mobile gateway is used to determine the networking situation. Two thresholds named ''upper-ratio'' and ''lower-ratio'' are set. When the average RTT exceeds the upper-ratio multiplies the maximum RTT, the networking situation is set to congested; when the average RTT is under the lower-ratio multiplies the maximum RTT, the networking situation is set to unloaded. The transmission mode is switched from ''redundant'' to ''duplicated'' when the networking situation is determined to be congested. The transmission mode is switched from ''duplicated'' to ''redundant'' when the networking situation is determined to be unloaded. In this way, the redundant information of packets is adapted to the networking situation and the bandwidth can be utilized more effectively.