Mohammed D. Halloush

Network Coding with Multi-Generation Mixing: Analysis and Applications for Video Communication

Network Coding (NC) is an emerging networking approach that improves overall throughput over packet networks. Meanwhile, traditional NC approaches have limited advantages under certain network conditions, such as sparse connectivity and high losses; this is especially true for real-time applications. In this paper, we propose and analyze a generalized approach of network coding, which is based on Multi-Generation Mixing (MGM). As we demonstrate in this paper, MGM-based NC improves the performance of real-time data communications under scenarios of sparse connectivity and high loss rates. Under such scenarios, practical network coding not only fail to achieve any improvements; on the contrary it may lead to performance degradations. The analytical as well as the simulation studies we present in this paper show major improvements that can be achieved in situations where practical network coding is not a viable option. In particular, we demonstrate major gains in PSNR video quality under MGM-based network coding.

Network coding with multi-generation mixing

Connectivity, losses, and buffering are factors that directly affect the performance of network coding. These factors affect the ability of intermediate nodes to generate useful encodings; these are encodings that contribute in propagating and recovering data at receiver node(s). It has been shown that in particular scenarios network coding performance can be improved by simply increasing the generation size (k); however, this leads to increasing transmission overhead, encoding complexity and (more importantly) buffer sizes at intermediate nodes. In this paper, we propose a new network coding approach where we employ Multi-Generation Mixing (MGM). MGM eliminates the need to increasing buffer sizes while improving the performance of network coding. Under MGM, we define a mixing set of size m generations that can be network coded (mixed) together. Within each MGM mixing set, a new set of generation packets are mixed with previously transmitted (network coded) generations. This generalized approach provides a great deal of resilience against losses when compared with traditional generation-based network coding. Our analysis of the performance of MGM-based network coding demonstrates significant reduction in required overhead for a given recovery performance at the receivers. We also illustrate the performance of MGM using extensive simulations that provide a useful insight into the viability of MGM-based network coding.

Network Coding with Multi-Generation Mixing: A Generalized Framework for Practical Network Coding

Due to the broadcast nature of wireless networks they have been a natural platform for applying Network Coding (NC). Wireless networks can benefit significantly from NC due to their broadcast nature and the opportunity of enhancing bandwidth utilization. In this paper, we develop Multi-Generation Mixing (MGM), which is a generalized approach for generation based network coding. With traditional generation based NC sender packets are grouped in generations where encoding and decoding are performed on packets that belong to the same generation. In scenarios where losses cause insufficient reception of encoded packets, NC losses occur. NC losses are expensive; the minimum unit of loss is the loss of one generation. The proposed MGM framework allows the encoding among generations for the purpose of enhancing NC decodability. With MGM in scenarios where insufficient number of encodings received of a generation, it is still possible to recover the generation using data encoded in other generations. We develop MGM encoding and decoding approaches, and demonstrate the improvements in performance achieved by MGM. Further, a canonical analytical model for MGM network coding is developed, and, extensive simulations over random wireless networks experiencing random packet losses are presented.

Practical Network Coding for scalable video in error prone networks

In this paper we apply a generalized approach for practical Network Coding (NC) called Multi-Generation Mixing (MGM) in networks communicating scalable video contents. NC has been a viable approach of communication in packet loss networks. On the other hand NC losses are expensive. NC losses reduce the ability of receiver to decode packets, and hence may severely degrade the quality of recovered video. MGM employs the layering of scalable video streams to enhance the reliability of communication. MGM provides unequal protection for the different video layers such that the overall reliability of video communication is improved. With MGM instead of having enhancement layers just dependent on lower layers, enhancement layers support the recovery of lower layers. This is done by network encoding packets of lower layers in higher layers. Through extensive simulations, we show that MGM highly improves the quality of recovered video.

A case study of: Sender transmission reliability and complexity using network coding with multi-generation mixing

A case study of: Sender transmission reliability and complexity using network coding with Multi-generation MImprovements in emerging practical network coding methods, such as Multi-generation Mixing (MGM), can be attributed to two arguably independent factors: (1) An intrinsic factor that is due to the cooperation among intermediate (propagating) nodes in mixing traffic received through multiple routing paths. (2) An extrinsic factor that is due to the level of reliability provided by network coding from the sender toward the intermediate nodes. The vast majority of prior work has primarily focused on the intrinsic factor, while the impact of reliability of sender transmission toward the network (extrinsic factor of network coding) has not been largely investigated. In this paper we evaluate the performance of network coding with MGM in improving the reliability of sender transmission. Since MGM is a generalized approach for practical network coding, we adopt MGM for conducting this study. Using different loss models and through extensive simulations we evaluate the performance of MGM as well as traditional generation based NC (a special case of MGM) and their ability in reliably transmitting sender packets.

Performance evaluation: Priority transmission using network coding with multi-generation mixing

In this paper, we evaluate the priority transmission characteristic of Network Coding (NC) with Multi-Generation Mixing (MGM). MGM supports priority transmission by providing enhanced reliability for delivering different groups of sender packets. MGM is a generalized approach for practical network coding that enhances its performance. With MGM, sender packets are grouped in generations that constitute mixing sets. By employing the novel inter-generation network coding approach, each generation within a mixing set can be considered as a priority layer. This is due to the varying levels of data protection provided to the different generations within a mixing set. Traditionally, priority transmission is done by increasing the level of FEC protection assigned to sender data of higher priority. This incurs transmission overhead that consumes bandwidth. MGM supports priority transmission by network encoding data of higher priority in more sender packets so that more packets support its recovery. At the same time there is no increase in the total number of packets transmitted and hence no additional transmission overhead.

On Varying Network Coding Forwarding Ratio in Vector Based Wireless Sensor Networks

Transmissions are costly in wireless sensor networks due to energy constraints in sensor nodes. In this work we apply network coding in WSNs that use Vector Based Forwarding (VBF) as a routing protocol. The goal is to decrease the total number of transmissions performed to deliver data. The proposed forwarding mechanism is location based. This means that the number of transmissions performed by a node depends on the location of that node within the VBF routing vector. Through simulations we evaluate the proposed forwarding mechanism. Results indicate major improvements in the total number of transmissions needed and the amount of traffic generated while propagating data to destination reliably.

A Framework for Video Network Coding with multi-generation mixing

Multi-Generation Mixing (MGM) is a generalized approach of Network Coding (NC) that has its improvements when applied in packet loss networks. In this paper we apply MGM network coding in networks communicating video contents. NC has shown viable improvements when applied in packet loss networks. With practical network coding (generation based network coding), packets are grouped in chunks called generations. Generation is the unit of network coding encoding and decoding. The generation grouping of packets is necessary for the practical deployment of network coding. On the other hand it increases the cost of NC losses. NC losses reduce the ability of receiver to decode packets, and hence can severely degrade the quality of recovered video. Video is encoded in layers with Scalable Video Coding (SVC) a base layer and one or more enhancement layers. MGM employs the layering of scalable video to enhance the reliability of communication. MGM provides different levels of reliable communication for the different video layers to improve the overall reliability of video communication. SVC enhancement layers are dependent on lower layers to be recovered. With MGM enhancement layers support the recovery of lower layers. This is done by network encoding lower video layers in higher layers. Through extensive simulations, we show that MGM highly improves the quality of recovered video.

The unequal protection of Network Coding with multi-generation mixing

In this paper, we study and analyze the unequal protection characteristic of Network Coding (NC) with Multi-generation Mixing (MGM). MGM supports unequal protection by providing different levels of reliable communication for different groups of sender packets. MGM is a generalized framework for practical network coding that enhances its performance by improving the reliability of delivering sender packets [10]. By employing MGM, generations are created from sender packets. At the same time a mixing set consists of a fixed number of generations. In this paper we analyze the capability of MGM to support unequal protection of MGM mixing set generations.

Adaptive forwarding using network coding in vector-based wireless sensor networks

Network Coding NC has been applied in Wireless Sensor Networks WSNs where major improvements have been achieved. In this paper, we propose a network coding routing mechanism in WSNs that is based on Vector-Based Forwarding VBF. The goal of the proposed routing mechanism is to decrease the total number of transmissions needed to deliver data to the destination. Decreasing the total number of transmissions is achieved by varying the number of transmissions performed by each sensor node in a particular way that does not sacrifice the reliability of data delivery. Decreasing the number of transmissions decreases the traffic forwarded in the process of delivering data and enhances power savings which prolong the lifetime of the WSN. Simulation results show major improvements achieved by the proposed routing mechanism.