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.
We study network coding capacity under a constraint on the total number of network nodes that can perform coding. That is, only a certain number of network nodes can produce coded outputs, whereas the remaining nodes ...
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We study network coding capacity under a constraint on the total number of network nodes that can perform coding. That is, only a certain number of network nodes can produce coded outputs, whereas the remaining nodes are limited to performing routing. We prove that every nonnegative, monotonically nondecreasing, eventually constant, rational-valued function on the nonnegative integers is equal to the capacity as a function of the number of allowable coding nodes of some directed acyclic network.
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.
Wireless body area networks (WBANs) have revolutionized healthcare by enabling remote supervision, prior detection, and disease interception using invasive and wearable sensor devices. The limited battery capacity of ...
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Wireless body area networks (WBANs) have revolutionized healthcare by enabling remote supervision, prior detection, and disease interception using invasive and wearable sensor devices. The limited battery capacity of the sensors coupled with the poor channel condition (that may arise from body postures) require cooperative transmission strategies that can prolong the sensors' life time and associated functionalities. Therefore, in this article, a cooperative scheme based on single-stage relaying is presented for spectrum and energy efficiency. The relay operating for two different scenarios, i.e. network coding and hierarchical modulation, is discussed. The general trend for bit error rate (BER) is observed by modeling a Rayleigh faded link catering path loss. The results are further studied for actual channel models, defined in WBAN standard. The effect of hop-length variation on BER and packet error rate (PER) are discussed. Simulation results show that both cooperative schemes outperform direct communication. A hybrid switching scheme is proposed to enhance efficiency.
Minimizing network coding resources of multicast networks,such as the number of coding nodes or links,has been proved to be NP-hard,and taking propagation delay into account makes the problem more complicated. To reso...
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Minimizing network coding resources of multicast networks,such as the number of coding nodes or links,has been proved to be NP-hard,and taking propagation delay into account makes the problem more complicated. To resolve this optimal problem,an integer encoding routing-based genetic algorithm( REGA) is presented to map the optimization problem into a genetic algorithm( GA)framework. Moreover,to speed up the search process of the algorithm,an efficient local search procedure which can reduce the searching space size is designed for searching the feasible *** with the binary link state encoding representation genetic algorithm( BLSGA),the chromosome length of REGA is shorter and just depends on the number of sinks. Simulation results show the advantages of the algorithm in terms of getting the optimal solution and algorithmic convergence speed.
Device-to-Device (D2D) communication is one of the critical technologies for the fifth-generation network, which allows devices to communicate directly with each other while increasing transmission rate, but this comm...
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Device-to-Device (D2D) communication is one of the critical technologies for the fifth-generation network, which allows devices to communicate directly with each other while increasing transmission rate, but this communication is vulnerable to interference. When video transmission is carried out in an environment with interference, problems such as high packet loss rate, poor quality of the video, and blurred screen may exist. These problems can be effectively solved by redundant coding operations at the source node, but the extra coding operation imposes a heavy computational burden on the source node. In order to alleviate the computational overhead of the source node, reduce transmission delay, and guarantee transmission quality, this paper proposes an efficient video multicast transmission scheme based on Random Linear network coding (RLNC) in D2D networks. In the scheme, the receiving devices in the transmission participate in the process of generating repair packets that are used to remedy the loss of encoded packets during transmission. The source node multicasts the encoded video file. The receiving nodes re-encode the received data packets with RLNC and then send them to the network again. The nearby nodes can decode the original data through the encoded or re-encoded data packets. The performance of the proposed scheme is evaluated through both simulation and real experiments. The experimental results show that compared with the traditional RLNC scheme, this scheme could balance the computation overhead of the mobile devices and reduce the encoding and decoding delay by about 8%. When the packet loss rate is high, the proposed scheme can obtain better video quality than the traditional replication-based scheme.
Kotter and Kschischang presented in 2008 a new model for error correcting codes in network coding. The alphabet in this model is the subspace lattice of a given vector space, a code is a subset of this lattice and the...
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Kotter and Kschischang presented in 2008 a new model for error correcting codes in network coding. The alphabet in this model is the subspace lattice of a given vector space, a code is a subset of this lattice and the used metric on this alphabet is the map d : (U, V) bar right arrow dim(U+V)-dim(U boolean AND V). In this paper we generalize this model to arbitrary modular lattices, i.e. we consider codes, which are subsets of modular lattices. The used metric in this general case is the map d : (u, v) bar right arrow h(u boolean OR v) - h(u boolean AND v), where h is the height function of the lattice. We apply this model to submodule lattices. Moreover, we show a method to compute the size of spheres in certain modular lattices and present a sphere packing bound, a sphere covering bound, and a Singleton bound for codes, which are subsets of modular lattices.
network coding has been proved to be an effective technique in improving the performance of data broadcast systems because clients requesting different data items can be served simultaneously in one broadcast. Previou...
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network coding has been proved to be an effective technique in improving the performance of data broadcast systems because clients requesting different data items can be served simultaneously in one broadcast. Previous studies showed that its efficiency is highly related to the content of clients' cache. However, existing data broadcast systems do not take network coding information into account when making cache replacement decisions. In this paper, we propose two networks coding-aware cache replacement policies called DLRU and DLRU-CP to supplement network coding assisted data broadcast in on-demand broadcast environments. In DLRU, both data access and decoding contribution are taken into account to make replacement decisions. DLRU-CP is based on DLRU but allows clients to retrieve decodable data items that have not been requested yet. The performance gain of our proposed cache replacement policies over traditional cache replacement policy is shown in the simulation results, which demonstrate conclusively that the proposed policies can effectively reduce the overall response time.
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