This paper proposes a networkcoding method with linear mapping and low-complexity estimation for the two-way relay non-reciprocal channel using the M-QAM modulation. The proposed networkcoding is developed by combin...
详细信息
This paper proposes a networkcoding method with linear mapping and low-complexity estimation for the two-way relay non-reciprocal channel using the M-QAM modulation. The proposed networkcoding is developed by combining the channel quantization method and linear estimation based on successive interference cancellation. The effect of residual interference due to channel quantization on the signal decision is analyzed in detail in order to understand the system- behavior. Analytical and simulation results show that the proposed networkcoding method can achieve high SER performance and up-link throughput while requiring low computational complexity. (C) 2018 Elsevier GmbH. All rights reserved.
The integrated space and terrestrial networks which incorporate various satellite systems and ground networks could provide a wide variety of services and global seamless network access. The integrated network is comp...
详细信息
The integrated space and terrestrial networks which incorporate various satellite systems and ground networks could provide a wide variety of services and global seamless network access. The integrated network is composed of multiple heterogeneous nodes and sub-networks which requires intelligent and efficient physicallayer transmission techniques to maintain high-speed links between these subsystems. As a traditional technology in satellite communications, relay could still work as an important part in these heterogeneous and complex networks. In this paper, two interference exploitation schemes, i.e., physical-layer network coding (PNC) and successive interference cancellation (SIC) which can efficiently increase data exchange rate for relay systems are studied, and an intelligent relaying scheme combining both the advantages of these two schemes is proposed. Simulation results show the proposed adaptive transmission scheme achieves a smoother sum-rate gain while being more robust to dynamic topologies.
In this letter, a physical-layer network coding (PNC) scheme based on continuous phase modulation (CPM) signal using the titled-phase model, i.e., TIP-CPM-PNC, is presented, and the combined titled-phase state trellis...
详细信息
In this letter, a physical-layer network coding (PNC) scheme based on continuous phase modulation (CPM) signal using the titled-phase model, i.e., TIP-CPM-PNC, is presented, and the combined titled-phase state trellis for the superimposed CPM signal in TIP-CPM-PNC is discussed. Simulation results show that the proposed scheme with low decoding complexity can achieve the same error performance as CPM-PNC using the traditional-phase model.
A three-user two-way channel in which three users exchange their messages through a two-way communication is considered by applying the physical-layer network coding and the superposition coding. The equivalent square...
详细信息
A three-user two-way channel in which three users exchange their messages through a two-way communication is considered by applying the physical-layer network coding and the superposition coding. The equivalent squared minimum distance (ESMD) is derived as a criterion for power allocation by analysing the average symbol error probability (SEP). Optimal and suboptimal power allocations are proposed based on the ESMD maximisation under total power constraint. Inspired by the result, a proportional power allocation is proposed under per-node power constraint. This scheme improves SEP at high signal-to-noise ratio (SNR) and consumes significantly less power. The average power consumption for each node is mathematically derived as a closed form. Furthermore, a compensation algorithm is introduced, which saves power and simultaneously achieves remarkable SEP improvement over entire SNR range. The numerical simulations over Rayleigh fading channels confirm the superiority of the proposed algorithms.
This paper presents the first implementation of a two-way relay network based on the principle of physical-layer network coding. To date, only a simplified version of physical-layer network coding (PNC), called analog...
详细信息
ISBN:
(纸本)9781457720536
This paper presents the first implementation of a two-way relay network based on the principle of physical-layer network coding. To date, only a simplified version of physical-layer network coding (PNC), called analog networkcoding (ANC), has been successfully implemented. The advantage of ANC is that it is simple to implement;the disadvantage, on the other hand, is that the relay amplifies the noise along with the signal before forwarding the signal. PNC systems in which the relay performs XOR or other denoising PNC mappings of the received signal have the potential for significantly better performance. However, their implementation also poses many challenges. For example, the relay must be able to deal with symbol and carrier-phase asynchronies of the simultaneous signals received from the two end nodes, and the relay must perform channel estimation before decoding. We investigate a PNC implementation in the frequency domain, referred to as FPNC, to tackle these challenges. FPNC is based on OFDM. In FPNC, XOR mapping is performed on the OFDM samples in each subcarrier rather than on the samples in the time domain. We implement FPNC on the universal soft radio peripheral (USRP) platform. Our implementation requires only moderate modifications of the packet preamble design of 802.11a/g OFDM PHY. With the help of the cyclic prefix (CP) in OFDM, symbol asynchrony and the multi-path fading effects can be dealt with simultaneously in a similar fashion. Our experimental results show that symbol-synchronous and symbol-asynchronous FPNC have essentially the same BER performance, for both channel-coded and unchannel-coded FPNC.
A physical-layer network coding (PNC) aided two-way relay scheme is proposed for Transmitted-Reference (TR) UWB networks. In particular, a novel noncoherent UWB-PNC detector is investigated for the TR-UWB networks. In...
详细信息
ISBN:
(纸本)9781424492688
A physical-layer network coding (PNC) aided two-way relay scheme is proposed for Transmitted-Reference (TR) UWB networks. In particular, a novel noncoherent UWB-PNC detector is investigated for the TR-UWB networks. Inheriting the simplicity of the TR-UWB receiver, the proposed PNC detector is based on the autocorrelation receiver (AcR) with simple structure, which effectively suppresses the multi-user interference and harvests the multipath energy. Equipped with the proposed TR UWB-PNC detector, the relay node first detects the bitwise XORed symbol directly from the overlapped information bearing waveforms transmitted from the source nodes, then broadcasts the estimate of the XORed symbol to achieve efficient two-way relay. Simulation results show that, compared with the non-relay, one-way relay and two-way relay with time division multiple access (TDMA) and network coded broadcasting (NCBC), the proposed PNC aided two-way scheme significantly improves both the energy and spectral efficiencies of the TR-UWB networks.
networkcoding recognized as an efficient solution on improving network throughput is a hot spot in the area of wireless network. However, interference affects quality of communication seriously, which is a harmful fa...
详细信息
ISBN:
(纸本)9783642232251
networkcoding recognized as an efficient solution on improving network throughput is a hot spot in the area of wireless network. However, interference affects quality of communication seriously, which is a harmful factor in wireless fading environment. One protocol named physical-layer network coding not only increase network throughput but also takes advantage of interference between signals. How to separate the mixed signal resulting from the broadcast nature of wireless channel is an area with little discussion. This paper firstly proposes a PNC decoding solution for mixed signal separation in Multi Access Relay Channel(MARC) model. Then we use our estimation result about the channel coefficients to give a discussion on the capacity theorem of MARC model using PNC. In conclusion, the simulation result tells that the proposed method ARD PNC performs well in PNC with higher bandwidth utility and lower error rate. At the same time, the capacity using PNC is also improved comparing to traditional direct transmission.
networkcoding, which works in the networklayer, is an effective technology to improve the throughput of two-way relay networks. In this paper, we compare the existing networkcoding schemes: traditional network codi...
详细信息
ISBN:
(纸本)9781457720536
networkcoding, which works in the networklayer, is an effective technology to improve the throughput of two-way relay networks. In this paper, we compare the existing networkcoding schemes: traditional networkcoding (NC) scheme, physical-layer network coding (PNC) scheme and soft networkcoding (SNC) scheme, and propose a new physicallayer scheme which can be seen as the implementation of networkcoding in two-way relay networks. Relay nodes combine the received signals from two source nodes before demodulation and channel decoding. The computational complexity and BER performance of the proposed scheme are analyzed compared with the previous schemes. Theoretical analysis show that the proposed scheme can save 50% computational cost of demodulation and channel decoding processes compared with NC scheme, meanwhile increase the power efficiency of the relay nodes in two-way relay networks significantly. Future works with the proposed scheme are also discussed.
In this paper, a network scenario of two-way relaying over orthogonal frequency division multiplexing (OFDM) is considered, in which two nodes intend to exchange the information via a relay using physical-layer netw...
详细信息
In this paper, a network scenario of two-way relaying over orthogonal frequency division multiplexing (OFDM) is considered, in which two nodes intend to exchange the information via a relay using physical-layer network coding (PLNC). Assuming that the full channel knowledge is available, an optimization problem, which maximizes the achievable sum rate under a sum-power constraint, is investigated. It is shown that the optimization problem is non-convex, which is difficult to find the global optimum solution in terms of the computational complexity. In consequence, a low-complexity optimal power allocation scheme is proposed for practice implementation. A link capacity diagram is first employed for power allocation on each subcarrier. Subsequently, an equivalent relaxed optimization problem and Karush-Kuhn-Tucker (KKT) conditions are developed for power allocation among each subcarrier. Simulation results demonstrate that the substantial capacity gains are achieved by implementing the proposed schemes efficiently with a low-complexity computational effort.
This paper presents the first network-coded multiple access (NCMA) downlink system on unmanned aerial vehicle (UAV). The use of UAV as a mobile aerial base station has received much attention in the 5G community in th...
详细信息
This paper presents the first network-coded multiple access (NCMA) downlink system on unmanned aerial vehicle (UAV). The use of UAV as a mobile aerial base station has received much attention in the 5G community in the context of highly mobile and flexible-configurable communication systems. As UAVs are limited by their flight time in the air, achieving high spectral and power efficiency while they are inflight is of great importance. Non-orthogonal multiple access (NOMA) is a promising technique to increase the spectral and power efficiency. Conventional NOMA downlink that makes use of superposition coding in combination with successive interference cancellation (SIC) decoding does not work well in scenarios where the channel conditions of different downlink users are not readily available at the transmitter side. This is the case, for example, in the UAV scenario in which the UAV transmitter moves quickly, causing the channel conditions to vary in a very dynamic manner. This paper investigates a new NOMA downlink architecture, referred to as network-coded multiple access. In the absence of channel information, an NCMA transmitter allocates equal power to the superposed signals of different downlink users. A key challenge is how to achieve high NOMA throughput under such equal power allocation. Toward this end, NCMA makes joint use of physical-layer network coding (PNC) and multiuser decoding (MUD) together with a new superposition coding scheme, referred to as NCMA-based superposition coding. In NCMA-based superposition coding, equal powers are allocated to the signals of different users, but a relative phase offset between the signals is introduced to optimize PNC and MUD decodings. To demonstrate the feasibility and advantage of the NCMA downlink, we implemented our designs on a software-defined radio and UAV. Our experimental results show that NCMA is robust against varying channel conditions. Moreover, the throughput of NCMA can outperform the state-of-the-art
暂无评论