To deal with the explosive traffic demand, caching at the edge of mobile networks has been proposed to improve the quality of user experience. Presently, the edge caching systems are based on the direct and simple rel...
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To deal with the explosive traffic demand, caching at the edge of mobile networks has been proposed to improve the quality of user experience. Presently, the edge caching systems are based on the direct and simple relay transmission, which is hard to achieve high system throughput and good content service. In such situations, network coding can effectively solve these problems. One problem arises in the application of network coding: how to form X topology network. We formulate the X topology formation problem as a function of system throughput and content service satisfaction degree. Then we propose a coalition game theory based algorithm to solve this NP-hard problem and prove the Nash stability of our coalition formation game. We evaluate our proposed algorithm through extensive simulations in different network environments. The experiment results demonstrate that our algorithm achieves nearly optimal performance and significantly outperforms the four widely-accepted baseline algorithms.
There has been an increasing demand for providing real-time video streaming services in the next-generation cellular networks. To improve the quality of such services without additional infrastructure, neighboring dev...
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There has been an increasing demand for providing real-time video streaming services in the next-generation cellular networks. To improve the quality of such services without additional infrastructure, neighboring devices can recover missing packets by using network coding aided collaborative transmission via device-to-device (D2D) communication. However, most existing work in this area had not considered the issue of how to schedule such coding aided collaborative transmissions effectively for supporting real-time scalable video applications in such environment. In this paper, we study how to improve the quality of real-time scalable video services by efficiently scheduling coding aided collaborative transmissions. We first formulate the problem of optimal collaborative transmission scheduling that determines the optimal transmitting sequence and coding pattern at each transmitting device, which is shown to be NP-hard. To address this problem, we propose a new weight function for measuring the quality of a coding pattern by considering packet recovery gain and potential video decoding gain at receivers. Based on this new weight function, we propose a low complexity centralized algorithm using global state information and an efficient distributed mechanism supporting localized operations in dynamic environment. We deduce their computational complexities. Simulation results verify that the proposed solution outperforms the representative work in the literature.
Nowadays, wireless networks are employed for many applications, but they face some problems such as power source limitation and collision due to common media. These problems decrease the network throughput and increas...
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Nowadays, wireless networks are employed for many applications, but they face some problems such as power source limitation and collision due to common media. These problems decrease the network throughput and increase the power consumption. Fading is another important characteristic of wireless channels, which degrades the network performance. On the contrary, network coding is a useful method that can be applied to increase throughput. We extend the network coding model from two nodes with one relay to four nodes with the same relay over Rayleigh fading channels. Each side of the relay consists of two neighbouring nodes, which relaying nodes are not needed between them. In this paper, we propose a new method that uses priority property for decoding so that high or low priority for a node means that the node will XOR received data from relay node and its own data or data received from its neighbour, respectively. Also, decoding procedure includes two stages in which one of the neighbour nodes in each side has high priority and the other one has low priority. Then, network performance and the effects of Rayleigh fading on network coding over double-link channels are studied under power-constant and channel-inversion schemes. By solving optimisation problems called Double-Link network coding Constant Power and Double-Link network coding Channel Inversion, we obtain optimum network throughput. The results show that the proposed method increases network throughput and decreases power consumption by reducing number of time slots in comparison with the simple method. Copyright (c) 2013 John Wiley & Sons, Ltd.
In offices and residential buildings. WiFi networks have become a primary means for providing Internet access to wireless devices whose dominant traffic pattern is unicast. In the meantime, the emergence of network co...
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In offices and residential buildings. WiFi networks have become a primary means for providing Internet access to wireless devices whose dominant traffic pattern is unicast. In the meantime, the emergence of network coding has brought about great promises for multicast in communication networks where intermediate nodes are allowed to process independent incoming information flows. Little is known about network coding for unicast, however. The objective of this paper is thus to depart from multicast scenarios and shed light on several possible unicast scenarios to which network coding may be applied in a WiFi hotspot in order to obtain communication benefits such as throughput gain, fairness, and reduced protocol complexity. We identify five representative scenarios in which network coding may be used to benefit unicasting in a WiFi hotspot. Several open research issues and practical challenges related to each scenario are discussed individually. To illustrate the benefits of network coding for unicast in a WiFi hotspot, we propose and implement iCORE: The interface COoperation Repeater-aided network coding Engine. iCORE is a practical system in which multi-channel multi-radio repeaters are used to relay unicast traffic for those terminals sitting far away from an access point and suffering from weak signals at a WiFi hotspot. It is based on our last scenario which illustrates the synergy among network coding, opportunistic routing, and interface management. Utilizing idle wireless interfaces and listening to traffic opportunistically, iCORE allows packets to move across the interfaces and to be coded across flows whenever it sees more transmission opportunities. We evaluate iCORE on a four-node chain-like topology testbed implemented using IEEE 802.11b/g radios and compare it to MORE - the state-of-art intra-flow network coding implementation based on opportunistic routing. Our experimental results reveal promising gains in terms of throughput over MORE. (C) 2012 Els
In this letter, we consider a new communication scenario in cellular networks, which is called intra-cell communications (ICC), for which user pairs within the same cell exchange information through the base station (...
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In this letter, we consider a new communication scenario in cellular networks, which is called intra-cell communications (ICC), for which user pairs within the same cell exchange information through the base station (BS). A network coding based protocol is proposed to assist ICC in OFDMA networks to improve the spectral efficiency. In the uplink, each user accesses the BS following the OFDMA principle, while in the downlink, the BS transmits to each of the user pairs using the OFDMA principle. To do so, the BS performs bit level XOR (BLX) operation on the information bits received from each user pair. The output is then transmitted back to the same user pair through subcarrier sharing. We formulate the joint uplink/downlink subcarrier assignment and power allocation problem to maximize the weighted sum rate. While the formulated problem is non-convex, an asymptotically optimal, yet low complexity algorithm is proposed. Simulation results are presented to verify that the proposed protocol outperforms subcarrier pairing and assignment schemes which require no subcarrier sharing in both uplink and downlink.
We consider the information exchange problem where each in a set of terminals transmits information to all other terminals in the set, over an undirected network. We show that the design of only a single network code ...
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We consider the information exchange problem where each in a set of terminals transmits information to all other terminals in the set, over an undirected network. We show that the design of only a single network code for multicasting is sufficient to achieve an arbitrary point in the achievable rate region. We also provide an alternative proof for the set of achievable rate tuples.
In this letter, we consider an end-to-end loss network with a limited delay and investigate the maximum network coding rate achievable under a given block length and error probability. We first formulate block network...
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In this letter, we consider an end-to-end loss network with a limited delay and investigate the maximum network coding rate achievable under a given block length and error probability. We first formulate block network coding for reliable data transmission as an optimization problem and then analyze the throughput, success probability and delay in terms of block length and packet loss probability for block network coding. Results show that the coding rate gradually approaches the capacity 1-e as the delay increases, where e is the packet loss probability. When feedback is allowed in the limited delay, the rate increases in a faster way compared with no retransmission.
In Unattended Wireless Sensor networks(UWSNs), sensed data are stored locally for a long term till to collector's retrieval. It is motivated by the scenarios where only historical information or digest data, not r...
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network coding has recently emerged as an alternative to traditional routing algorithms in communication systems. In network coding, the network nodes combine the packets they receive before forwarding them to the nei...
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This special issue includes a collection of 19 outstanding research papers which cover a diversity of topics on the application of network coding in wireless communication networks.
This special issue includes a collection of 19 outstanding research papers which cover a diversity of topics on the application of network coding in wireless communication networks.
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