Decoding Delay Minimization in Inter-Session Network Coding

Journal of Communications, 2009

Network coding is a promising generalization of routing which allows a network node to generate output messages by encoding its received messages to reduce the bandwidth consumption in the network. An important application where network coding offers unique advantages is the multicast network where a source node generates messages and multiple receivers collect the messages. Previous network coding schemes primarily considered encoding the messages in a single multicast session. In this paper, we consider the linear inter-session network coding for multicast. The basic idea is to divide the sessions into different groups and construct a linear network coding scheme for each group. To maximize the performance, we introduce two metrics: overlap ratio and overlap width, to measure the benefit that a system can achieve by inter-session network coding. The overlap ratio mainly characterizes the network bandwidth while the overlap width characterizes the system throughput. Our simulation results show that the proposed inter-session network coding scheme can achieve about ¿¼± higher throughput than intra-session network coding.

IEEE Transactions on Vehicular Technology, 2015

We propose a network coding strategy for multicast applications called the simple network coding scheme, which takes network coding chances raised among adjacent nodes. The proposed scheme incorporates both intrasession and intersession network coding strategies and effectively improves multicast throughput. We characterize the capacity region of the proposed scheme and derive an optimal control algorithm for the proposed scheme. We perform a complexity analysis for the proposed control algorithm and provide some insights into its practical implementation. For a comparison, we also formulate the capacity region of conventional multicast schemes and provide performance evaluation using a linear programming solver. In empirical analyses, we investigate how the proposed scheme improves multicast throughput gains from various perspectives (i.e., the number of flows, the number of network coded packets, and split-multicast) and find out that most of the gains can be achieved by simple pairwise network coding with non-split-multicast. We observe dramatic throughput gains up to 75% beyond the conventional schemes on random topologies with ten nodes.

Proceedings of the 4th International ICST Conference on Wireless Internet, 2008

Multicasting is the delivery of common information to multiple receivers. It finds its application in multi-media broadcasts, group communication in social networks etc. The multicast traffic in networks can constitute a significant portion of the total traffic (e.g. 80% in military communications) and hence it is imperative that they are served efficiently. So far "single rate" multicasting, where all receivers receive the data at a common rate from the source has attracted most of the attention . Yet, single-rate multicasting may yield low utilization of the network resources when a subset of the receivers creates a bottleneck for the whole multicast group. Multirate multicasting is a strategy where the source is allowed to multicast its data to different destinations at different rates based on the condition of the network to them. Multirate multicasting allows users with better channels to achieve maximum performance.

IEEE Transactions on Information Theory, 2000

We establish, for multiple multicast sessions with intra-session network coding, the capacity region of input rates for which the network remains stable in ergodically time-varying networks. Building on the back-pressure approach introduced by Tassiulas et al., we present dynamic algorithms for multicast routing, network coding, rate control, power allocation, and scheduling that achieves stability for rates within the capacity region. Decisions on routing, network coding, and scheduling between different sessions at a node are made locally at each node based on virtual queues for different sinks. For correlated sources, the sinks locally determine and control transmission rates across the sources. The proposed approach yields a completely distributed algorithm for wired networks. In the wireless case, scheduling and power control among different transmitters are centralized while routing, network coding, and scheduling between different sessions at a given node are distributed.

2012

Abstract Multi-layer video streaming allows to provide different video qualities to a group of multicast receivers with heterogeneous receive rates. The number of layers received determines the quality of the decoded video stream. For such layered multicast streaming, network coding provides higher capacity than multicast routing. Network coding can be performed within a layer (intra-layer) or across layers (inter-layer), and in general inter-layer coding outperforms intra-layer coding.

Here, we characterize the throughput of a broad cast network with receivers using rate less codes with block size. We characterize the system throughput asymptotically. Specifically, we explicitly show how the throughput behaves for different values of the coding block size as a function. We are able to provide a lower bound on the maximum achievable throughput. Using simulations, we show the tightness of the bound with respect to system parameters and find that its performance is significantly better than the previously known lower bounds. The packets are not decidable if any deviation is occurred.

2011 IEEE International Conference on Communications (ICC), 2011

This paper addresses the problem of inter-session network coding to maximize throughput for multiple communication sessions in wireless networks. We introduce virtual multicast connections which can extract packets from original sessions and code them together. Random linear network codes can be used for these virtual multicasts. The problem can be stated as a flowbased convex optimization problem with side constraints. The proposed formulation provides a rate region which is at least as large as the region without inter-session network coding. We show the benefits of our technique for several scenarios by means of simulation.

2012 19th International Packet Video Workshop (PV), 2012

In this work, we propose a distributed rate allocation algorithm that minimizes the average decoding delay for multimedia clients in inter-session network coding systems. We consider a scenario where the users are organized in a mesh network and each user requests the content of one of the available sources. We propose a novel distributed algorithm where network users determine the coding operations and the packet rates to be requested from the parent nodes, such that the decoding delay is minimized for all the clients. A rate allocation problem is solved by every user, which seeks the rates that minimize the average decoding delay for its children and for itself. Since the optimization problem is a priori non-convex, we introduce the concept of equivalent packet flows, which permits to estimate the expected number of packets that every user needs to collect for decoding. We then decompose our original rate allocation problem into a set of convex subproblems, which are eventually combined to obtain an effective approximate solution to the delay minimization problem. The results demonstrate that the proposed scheme eliminates the bottlenecks and reduces the decoding delay experienced by users with limited bandwidth resources. We validate the performance of our distributed rate allocation algorithm in different video streaming scenarios using the NS-3 network simulator. We show that our system is able to take benefit of inter-session network coding for simultaneous delivery of video sessions in networks with path diversity.

MILCOM 2007 - IEEE Military Communications Conference, 2007

This paper investigates the interaction between network coding and link-layer transmission rate diversity in multihop wireless networks. By appropriately mixing data packets at intermediate nodes, network coding allows a single multicast flow to achieve higher throughput to a set of receivers. Broadcast applications can also exploit link-layer rate diversity, whereby individual nodes can transmit at faster rates at the expense of corresponding smaller coverage area. We first demonstrate how combining rate-diversity with network coding can provide a larger capacity for data dissemination of a single multicast flow, and how consideration of rate diversity is critical for maximizing system throughput. We also study the impact of both network coding and rate diversity on the dissemination latency for a class of quasi real-time applications, where the freshness of disseminated data is important. Our results provide evidence that network coding may lead to a latency-vs-throughput tradeoff in wireless environments, and that it is thus necessary to adapt the degree of network coding to ensure conformance to both throughput and latency objectives. There is an increasing interest in understanding the potential performance gains accruing from the use of network coding in multi-hop wireless environments. In particular, many military battlefield scenarios exhibit two characteristics that appear to motivate the use of network coding: a) the reliance on bandwidth-constrained, ad-hoc wireless links (e.g. using MANETs formed by vehicle-mounted radios in urban insurgencies) and b) the need to disseminate information (e.g., maps, mission commands) to multiple recipients. The initial results on the power of network coding NC, such as the original demonstration in [1] of how in-network mixing of packets by intermediate nodes helps to achieve a communication capacity that is not achievable solely through routing, were obtained for the case of a lossless, wireline network. More recently, several groups have investigated the potential performance gains realized by network coding for both

2008 5th IEEE International Conference on Mobile Ad Hoc and Sensor Systems, 2008

Network coding is a highly efficient data dissemination mechanism for wireless networks. Since network coded information can only be recovered after delivering a sufficient number of coded packets, the resulting decoding delay can become problematic for delay-sensitive applications such as real-time media streaming. Motivated by this observation, we consider several algorithms that minimize the decoding delay and analyze their performance by means of simulation. The algorithms differ both in the required information about the state of the neighbors' buffers and in the way this knowledge is used to decide which packets to combine through coding operations. Our results show that a greedy algorithm, whose encodings maximize the number of nodes at which a coded packet is immediately decodable significantly outperforms existing network coding protocols.