Residual loop-interference(LI)poses a significant challenge for the full-duplex(FD)unmanned aerial vehicle(UAV).To address the issue of residual LI,this paper proposes an amplify-and-forward(AaF)FD-UAV relay system ba...Residual loop-interference(LI)poses a significant challenge for the full-duplex(FD)unmanned aerial vehicle(UAV).To address the issue of residual LI,this paper proposes an amplify-and-forward(AaF)FD-UAV relay system based on a novel orthogonal frequency division multiplexing(OFDM)technique,in which a signal model of infinite impulse response(IIR)is established,instead of the classical finite impulse response(FIR).In the proposed scheme,the residual LI is considered a useful signal and can be combined with the novel OFDM to establish the IIR signal model.Meanwhile,the guard interval(GI)is designed to maintain the circular convolution structure,which differs from the cyclic prefix(CP)applied by the classical OFDM.At the receiver,the IIR signals are influenced only by Gaussian white noise.The proposed FD-UAV relay system can maintain a satisfactory bit error rate(BER)even in the presence of significant residual LI,compared to conventional solutions for suppressing LI on FD-UAV relay.Numerical simulations validate that our proposed scheme offers a fresh solution to the residual LI problem in FD-UAV communication.展开更多
This paper studies wireless vehicular communication(VehCom)in intelligent transportation systems using an orthogonal frequency division multiplexing with index modulation(OFDM-IM).In the concept of IM,data is transmit...This paper studies wireless vehicular communication(VehCom)in intelligent transportation systems using an orthogonal frequency division multiplexing with index modulation(OFDM-IM).In the concept of IM,data is transmitted not only through the modulated symbols but also via the indices of the active subcarriers.In contrast to the original OFDM,OFDM-IM activates only non-zero subcarriers,increasing energy efficiency.However,the pilotassisted channel estimation(CE)method is a significant challenge in OFDM-IM,where the desired pilot subcarrier interval is related to the OFDM-IM subblock length.This paper proposes a walsh-scattered pilot-assisted CE for OFDM-IM VehCom.The optimum walsh-scattered pilot assignment is proposed to improve the transmission efficiency.Furthermore,a space-time block code with a high transmit diversity gain is employed for OFDM-IM VehCom to enhance VehCom's signal quality.The results show that the proposed method performs higher CE accuracy and better bit-error rate with significant spectral and energy efficiencies than conventional methods.展开更多
基金the National Natural Science Foundation of China(No.62001333,No.52207167)the Scientific Research Project of Education Department of Hubei Province(No.D20221702)Hunan Provincial Natural Science Foundation(No.2022JJ50181)。
文摘Residual loop-interference(LI)poses a significant challenge for the full-duplex(FD)unmanned aerial vehicle(UAV).To address the issue of residual LI,this paper proposes an amplify-and-forward(AaF)FD-UAV relay system based on a novel orthogonal frequency division multiplexing(OFDM)technique,in which a signal model of infinite impulse response(IIR)is established,instead of the classical finite impulse response(FIR).In the proposed scheme,the residual LI is considered a useful signal and can be combined with the novel OFDM to establish the IIR signal model.Meanwhile,the guard interval(GI)is designed to maintain the circular convolution structure,which differs from the cyclic prefix(CP)applied by the classical OFDM.At the receiver,the IIR signals are influenced only by Gaussian white noise.The proposed FD-UAV relay system can maintain a satisfactory bit error rate(BER)even in the presence of significant residual LI,compared to conventional solutions for suppressing LI on FD-UAV relay.Numerical simulations validate that our proposed scheme offers a fresh solution to the residual LI problem in FD-UAV communication.
文摘This paper studies wireless vehicular communication(VehCom)in intelligent transportation systems using an orthogonal frequency division multiplexing with index modulation(OFDM-IM).In the concept of IM,data is transmitted not only through the modulated symbols but also via the indices of the active subcarriers.In contrast to the original OFDM,OFDM-IM activates only non-zero subcarriers,increasing energy efficiency.However,the pilotassisted channel estimation(CE)method is a significant challenge in OFDM-IM,where the desired pilot subcarrier interval is related to the OFDM-IM subblock length.This paper proposes a walsh-scattered pilot-assisted CE for OFDM-IM VehCom.The optimum walsh-scattered pilot assignment is proposed to improve the transmission efficiency.Furthermore,a space-time block code with a high transmit diversity gain is employed for OFDM-IM VehCom to enhance VehCom's signal quality.The results show that the proposed method performs higher CE accuracy and better bit-error rate with significant spectral and energy efficiencies than conventional methods.
