network coding is an elegant and novel technique to improve network throughput and performance. It is considered as a critical technology to facilitate ever-increasing demands of future wireless networks. It exploits ...
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network coding is an elegant and novel technique to improve network throughput and performance. It is considered as a critical technology to facilitate ever-increasing demands of future wireless networks. It exploits the broadcast nature of wireless media and cooperatively codes packets from different senders to provide reliable, secure, and efficient transmissions. Current research focuses on either transmission delay, coding complexity, forwarding security, or end-to-end throughput. network coding-aided solutions can recover lost packets without feedback, eliminate latency, reduce the routing cost on diverse paths, or optimize the capacity of unstable wireless networks. However, devices or smart sensors usually have limited computational capacity and some applications could not tolerate high decoding delay, which prevents network coding from being widely deployed in the real world. In recent years, many research methods consider simplifying decoding matrix or coding algorithm to alleviate the shortcoming of network coding and further satisfy the extreme demands of the future wireless network. This article summarizes complexity-optimized methods and explains the interaction effect of coding opportunities and decoding overhead. We propose a taxonomy of practical network coding methods and illustrate three practical directions on cutting computational complexity and enhancing progressive decoding. We also conclude the benefit and cost of current network coding algorithms along with the outline of future research.
The device-to-device communication-aided fog radio access network, referred to as D2D-aided F-RAN, takes advantage of caching at enhanced remote radio heads (eRRHs) and D2D proximity for improved system performance. F...
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The device-to-device communication-aided fog radio access network, referred to as D2D-aided F-RAN, takes advantage of caching at enhanced remote radio heads (eRRHs) and D2D proximity for improved system performance. For D2D-aided F-RAN, we develop a framework that exploits the cached contents at eRRHs, their transmission rates/powers, and previously received contents by different users to deliver the requesting contents to users with a minimum completion time. Given the intractability of the completion time minimization problem, we formulate it at each transmission by approximating the completion time and decoupling it into two subproblems. In the first subproblem, we minimize the possible completion time in eRRH downlink transmissions, while in the second subproblem, we maximize the number of users to be scheduled on D2D links. We design two theoretical graphs, namely interference-aware instantly decodable network coding (IA-IDNC) and D2D conflict graphs to reformulate two subproblems as maximum weight clique and maximum independent set problems, respectively. Using these graphs, we heuristically develop joint and coordinated scheduling approaches. Simulation results show that the proposed two approaches achieve a considerable performance gain in terms of the completion time minimization.
This letter proposes a polarization mapping (PM) for polar coded modulation with physical network coding (PM-PNC) over two-way relay channels (TWRC). The achievable information rates (AIRs) of the mapped bits within a...
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This letter proposes a polarization mapping (PM) for polar coded modulation with physical network coding (PM-PNC) over two-way relay channels (TWRC). The achievable information rates (AIRs) of the mapped bits within a XOR symbol from bit-wise XOR of two user symbols are significantly different, since the users adopt non-uniform PAM modulation to avoid mapping ambiguity. In the polar-coded PM-PNC, the original channels associated with the split information bit channel are mapped to the XOR bit stream with a larger AIR. In this way, the achieved rate of the split information channels can be maximized and is illustrated in distribution of split bit channel AIRs. Simulation results show that the proposed PM-PNC can achieve significant performance gains of more than 0.5 dB as compared to the bit-interleaved coded modulation (BICM) and multilevel coded (MLC) PNC systems over Gaussian and block fading channels.
This paper proposes coded modulation for physical layer network coding in multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) bi-directional wireless relay systems where precoding is ...
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This paper proposes coded modulation for physical layer network coding in multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) bi-directional wireless relay systems where precoding is applied. The proposed coded modulation enables the relays to decode the received signals, which improves the transmission performance. Soft input decoding for the proposed coded modulation is proposed. Furthermore, we propose two precoder weight optimization techniques, called "per subcarrier weight optimization" and "total weight optimization". This paper shows a precoder configuration based on the optimization with the lattice reduction or the sorted QR-decomposition. The performance of the proposed network coding is evaluated by computer simulation in a MIMO-OFDM two-hop wireless relay system with the 16 quadrature amplitude modulation (QAM) or the 256QAM. The proposed coded modulation attains a coding gain of about 2 dB at the BER of 10(-4). The total weight optimization achieves about 1 dB better BER performance than the other at the BER of 10(-4).
Satellite-based Internet of Things (S-IoT) is suggested to meet the emergency applications and services of ubiquitous terrestrial IoT user equipments (UEs) in the future IoT. Since the limited power constraints of the...
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Satellite-based Internet of Things (S-IoT) is suggested to meet the emergency applications and services of ubiquitous terrestrial IoT user equipments (UEs) in the future IoT. Since the limited power constraints of the satellite and the IoT UEs, it is a vital challenging to design an energy efficient transmission scheme, which can reduce the number of retransmission rounds while offer high throughput. In this article, we combine the network coding and hybrid automatic repeat request (HARQ) to propose a network coding HARQ (NC HARQ) transmission scheme for typical S-IoT scenarios, i.e., the multiple unicast downlink transmission and network coding bidirectional relaying scenarios. We derive the theoretical expressions for the metrics of system performance, including the average number of transmission rounds, the system throughput and the energy efficiency (EE). Specifically, our derivations are completed in two methods, i.e., the mutual information cumulation method and the matrix exponential (ME) distribution method. Based on the above analytical results, we formulate and solve the maximum EE optimization problem to obtain the optimal maximum transmission rounds in two typical communication scenarios. Simulations are provided to validate our analytical results, and confirm the improvement of our proposed NC HARQ scheme.
In random network coding (RNC)-enabled networks, a sufficient number of linearly independent encoded packets, i.e., generations, is guaranteed at the cost of high latency and energy consumption at the transmitter. Thi...
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In random network coding (RNC)-enabled networks, a sufficient number of linearly independent encoded packets, i.e., generations, is guaranteed at the cost of high latency and energy consumption at the transmitter. This letter aims to reduce the weighted sum of latency and energy while guaranteeing a targeted successful transmission probability, which is defined as the probability that the RNC-enabled network has sufficient generations when the transmitter receives a required number of acknowledgements (ACKs) feedback. An analytical framework and a deep learning-based method are developed. Results show that the latency and energy consumption are reduced by jointly optimizing the required number of ACKs and the transmit power at the transmitter.
Wireless networks are prone to interference due to their broadcast nature. In the design of most of the traditional networks, this broadcast nature is perceived as a performance-degrading factor. However, Physical Lay...
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Wireless networks are prone to interference due to their broadcast nature. In the design of most of the traditional networks, this broadcast nature is perceived as a performance-degrading factor. However, Physical Layer network coding (PNC) exploits this broadcast nature by enabling simultaneous transmissions from different sources and thereby enhances the performance of the wireless networks with respect to improvement in spectral efficiency, coverage, latency and security of the system. For fifth generation (5G) networks and beyond, massive multiple input multiple output (MIMO) is considered as a key physical layer technology. Thus, its combination with PNC can significantly enhance the performance of the network, facilitating capacity-coverage improvement, among other benefits. While the bit error rate performance of multiuser massive MIMO-PNC systems through linear detection has been investigated extensively, their coverage probability for a given target signal-to-noise ratio has not been explored yet. In this paper, we derive a closed form expression for coverage probability in PNC based multiuser massive MIMO systems employing zero-forcing equalization. Both theoretical and simulation results are provided for different number of users and antennas in the multiuser massive MIMO-PNC communications systems.
This paper proposes a hybrid encryption scheme for multi-relay (MR) physical-layer network coding (PNC). Based on the three-relay (3R) bidirectional communication model, first, we discuss the throughput performance of...
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In the battlefield reconnaissance and monitoring environment, the application of Wireless Sensor network (WSN) requires high timeliness and reliability of data transmission. To meet the battlefield demand, a transmiss...
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The randomized drop when seen (rDWS) scheme is an online, feedback-based network coding technique proven to be an efficient, lightweight variant of the deterministic drop when seen (DWS) scheme. We have proposed a non...
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The randomized drop when seen (rDWS) scheme is an online, feedback-based network coding technique proven to be an efficient, lightweight variant of the deterministic drop when seen (DWS) scheme. We have proposed a non-generation-based, generalized version of rDWS with stochastic packet arrival at the sender queue (SQ) in this letter. Next, a queueing analysis is performed to find the expected SQ length with respect to the load factor. Analysis shows that asymptotic SQ length in rDWS approaches the same of DWS as the innovativeness factor approaches unity, which establishes the effectiveness of rDWS in maintaining shorter expected SQ length.
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