We study the scaling law governing the delay gains of network coding as compared to traditional transmission strategies in unreliable wireless networks. We distinguish between two types of traffic, namely elastic and ...
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We study the scaling law governing the delay gains of network coding as compared to traditional transmission strategies in unreliable wireless networks. We distinguish between two types of traffic, namely elastic and inelastic, where the elasticity of a flow is based on the delay constraints associated with it. This novel formulation is useful in that it allows for the modeling of real-time traffic more accurately. Considering the limited availability of feedback in such systems, we focus on strategies with minimal acknowledgement requirements. Under both traffic types, we provide an extensive analysis of the gains of network coding as compared to traditional transmission strategies in a single-hop setting, and show that the gains are significant in general and can be considerably large in some cases. We further provide a method for realizing these gains in multi-hop networks with general topologies using the analysis of the single hop scenario.
This paper investigates the network coding resource minimization problem in the context of dynamic network environment. As a combination of multiagent systems and evolutionary algorithm, multiagent evolutionary algori...
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ISBN:
(纸本)9781510829039
This paper investigates the network coding resource minimization problem in the context of dynamic network environment. As a combination of multiagent systems and evolutionary algorithm, multiagent evolutionary algorithm（MAEA） is adapted for the above NP-hard problem. Simulation results demonstrate that the proposed MAEA outperforms a number of state-of-the-art evolutionary algorithms with respect to the solution quality.
The problem of characterizing the optimal rate achievable with analog network coding (ANC) for a unicast communication over general wireless relay networks is computationally hard. A relay node performing ANC scales a...
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The problem of characterizing the optimal rate achievable with analog network coding (ANC) for a unicast communication over general wireless relay networks is computationally hard. A relay node performing ANC scales and forwards its input signals. The source-destination channel in such communication scenarios is, in general, an intersymbol interference (ISI) channel which leads to the single-letter characterization of the optimal rate in terms of an optimization problem with nonconvex, non closed-form objective function and non-convex constraints. For a special class of such networks, called layered networks, a few key results and insights are however available. To gain insights into the nature of the optimal solution and to construct low-complexity schemes to characterize the optimal rate for general wireless relay networks, we need (1) network topologies that are regular enough for analysis, yet general enough to capture essential characteristics of general wireless relay networks, and (2) schemes to approximate the objective function in closed-form without significantly compromising the performance. Towards these two goals, this work proposes (1) nonlinear chain networks, and (2) two approximation schemes. We show that their combination allows us to tightly characterize the optimal ANC rate with low computational complexity for a much larger class of general wireless relay networks than possible with existing schemes.
Batch forwarding using intra-flow random linear network coding (RLNC) has been used to improve the performance of a wireless network constituent of lossy links. However, existing batch-based forwarding mechanisms in t...
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ISBN:
(数字)9781728131290
ISBN:
(纸本)9781728131306
Batch forwarding using intra-flow random linear network coding (RLNC) has been used to improve the performance of a wireless network constituent of lossy links. However, existing batch-based forwarding mechanisms in this aspect can lead to a lot of bandwidth waste and thus reduced transmission efficiency. In this paper, we design a Sliding WIndow based Multiple batch forwarding mechanism (SWIM) using RLNC. In SWIM, multiple batches are allowed to be sent out simultaneously in a way that the forwarding process is managed by a sliding window. In SWIM, adaptive rate assignment is used to assign bandwidth resources to different batches based on their decoding states at the destination, in order to make full use of the bandwidth resources. Simulation results show that SWIM can achieve improved throughput performance as compared with existing work.
We propose a combined channel-network coding solution for efficient user cooperation in wireless ad-hoc networks that comprise a host of terminals communicating to a common destination. The proposed framework, termed ...
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ISBN:
(纸本)142440505X
We propose a combined channel-network coding solution for efficient user cooperation in wireless ad-hoc networks that comprise a host of terminals communicating to a common destination. The proposed framework, termed generalized adaptive network coded cooperation or GANCC, addresses the challenge of inter-user outage, which widely persists in practical cooperation scenarios, by adaptively matching code graphs to instantaneous network graphs (topologies). Additionally, GANCC treats channel codes as an integral part of the network code, and in doing so not only extracts the most benefit from these codes but also provides a live example supporting the notion that network codes are generalization of channel codes (as well as source codes)
A physical-layer network coded two-way relay system applying Low-Density Parity-Check (LDPC) codes for error correction is considered in this paper, where two sources A and B desire to exchange information with each o...
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A physical-layer network coded two-way relay system applying Low-Density Parity-Check (LDPC) codes for error correction is considered in this paper, where two sources A and B desire to exchange information with each other by the help of a relay R. The critical process in such a system is the calculation of the network-coded transmit word at the relay on basis of the superimposed channel-coded QPSK words of the two sources. For this joint channel-decoding and network-encoding task a generalized Sum-Product Algorithm (SPA) over F 16 is developed. This novel iterative decoding approach outperforms other recently proposed schemes as demonstrated by simulations.
We propose a physical layer approach to detect the relay node that injects false data or adds channel errors into the network encoder in multiple access relay networks. The misbehaving relay is detected by using the m...
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We propose a physical layer approach to detect the relay node that injects false data or adds channel errors into the network encoder in multiple access relay networks. The misbehaving relay is detected by using the maximum a posteriori (MAP) detection rule which is optimal in the sense of minimizing the probability of incorrect decision (false alarm and miss detection). The proposed scheme does not require sending extra bits at the source, such as hash function or message authentication check bits, and hence there is no transmission overhead. The side information regarding the presence of forwarding misbehavior is exploited at the decoder to enhance the reliability of decoding. We derive the probability of false alarm and miss detection and the probability of bit error, taking into account the lossy nature of wireless links. We show that the proposed decoding with the aid of the MAP detection of misbehaving relay is within 1dB away from the genie-aided decoding.
Based on an information model that classifies intermediate nodes in multicast networks into network coding, routing and replicating nodes, multicast max-flow and minimum cost optimization frameworks are formulated to ...
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Based on an information model that classifies intermediate nodes in multicast networks into network coding, routing and replicating nodes, multicast max-flow and minimum cost optimization frameworks are formulated to solve optimization problems in wireless networks with or without network coding. Two special properties of wireless transmissions are taken into consideration, i.e., multi-hop cooperation and mutual interference among nodes. Using maximal ratio combining (MRC) for node cooperation and successive interference cancellation (SIC) for interference mitigation, signal-to-interference-plus-noise ratio (SINR) expressions for wireless nodes are derived. Such expressions are then used to modify the edge capacity in the optimization frameworks. The proposed method is helpful to the study of node cooperation and competition in multi-hop wireless communication networks.
In this paper, we propose two novel physical layer aware adaptive network coding schemes for time variant channels, one aiming to maximize the energy efficiency, the other exploiting also the variable modulation order...
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In this paper, we propose two novel physical layer aware adaptive network coding schemes for time variant channels, one aiming to maximize the energy efficiency, the other exploiting also the variable modulation order, in an adaptive way. The proposed schemes have been applied to different satellite communications scenarios with different Round Trip Times (RTT). Compared to adaptive network coding, and classical non-adaptive network coding schemes for time variant channels, used as benchmarks, the proposed schemes demonstrate that adaptation of packet transmission based on the channel variation and corresponding erasures allows for significant gains in terms of throughput, delay and energy efficiency. We shed light on the trade-off between energy efficiency and delay-throughput gains, demonstrating that conservative adaptive approaches that favor less transmission under high erasures, might cause higher delay and less throughput gains in comparison to non-conservative approaches that favor more transmission to account for high erasures.
Motivated by streaming applications with stringent delay constraints, we consider the design of online network coding algorithms with timely delivery guarantees. Assuming that the sender is providing the same data to ...
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ISBN:
(纸本)9781424435128
Motivated by streaming applications with stringent delay constraints, we consider the design of online network coding algorithms with timely delivery guarantees. Assuming that the sender is providing the same data to multiple receivers over independent packet erasure channels, we focus on the case of perfect feedback and heterogeneous erasure probabilities. Based on a general analytical framework for evaluating the decoding delay, we show that existing ARQ schemes fail to ensure that receivers with weak channels are able to recover from packet losses within reasonable time. To overcome this problem, we re-define the encoding rules in order to break the chains of linear combinations that cannot be decoded after one of the packets is lost. Our results show that sending uncoded packets at key times ensures that all the receivers are able to meet specific delay requirements with very high probability.
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