检索结果-南通市图书馆

science china(Information sciences) 2011年第1期54卷 129-135页

作者： zhou zhiqiang,li shaoqian & {3. yufan national key laboratory of science and technology on Communications,university of electronic science and technology of china,{3.du 610054,{13. national key laboratory of {3. and technology on Communications University of Electronic Science and Technology of China Chengdu China

Fast frequency hopping can reduce the degradation caused by *** performance of noise-normalized fast frequency-hopped M-ary orthogonal frequency-shift-keying(FFH/MFSK)receivers over frequency nonselective Rayleigh fading channels with partial-band noise jamming is *** of numerical evaluation,a closed-form error probability expression is given based on the theory of complex variables. The simulation results validate the analytical *** is shown that there is an optimum diversity order and the system performance gets better with an increase in the modulation order.

关键词： anti-jamming fast frequency hopping noise normalization combining Rayleigh fading

Performance analysis of FFH / BPSK system with partial band noise jamming and channel estimation error in high-mobility wireless communication scenarios

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 2014年第35期59卷 5011-5018页

作者： Yishan He yufan cheng Gang Wu shaoqian {3. national key laboratory of {3. and technology on Communications University of Electronic Science and Technology of China

In this paper,we analyze the bit error ratio(BER) of fast frequency hopping(FFH) system with binary phase shift keying(BPSK) in high-mobility wireless *** taking into account partial band noise jamming and channel estimation errors as Gaussian noise,both of maximal-ratio combining(MRC) and equal-gain combining(EGC) schemes are considered,and exact analytical BER expressions for MRC and EGC schemes are ***,a closed-form BER expression for the MRC scheme is also presented in high signal-to-noise ratio *** and simulation results demonstrate that,the FFH/BPSK schemes suffer from performance degradation in the presence of channel estimation *** worst case jamming factor is shown to be inversely proportional to the signal to jamming *** properly designed frequency hopping schemes and channel estimation schemes,the performance improvement is also observed as compared with the traditional noncoherent FFH/BFSK system.

关键词：信道估计误差 PSK系统性能分析噪声干扰无线信道通信方案高流动性频带

Joint Optimization of Peak-to-Average Power Ratio and Spectral Leakage in 5G Multicarrier Waveforms

在线全文

学校读者我要写书评

暂无评论

china Communications 2015年第S1期12卷 83-92页

作者： WEI Peng DAN lilin zhou {3. XIAO Yue WU Gang li shaoqian national key laboratory of {3. and technology on Communications University of Electronic Science and Technology of China

High peak-to-average-power ratio(PAPR) and spectral leakage are two main drawbacks of multicarrier systems, such as in orthogonal frequency division multiplexing(OFDM), in future 5G wireless communications. For generating optimized wave forms for 5G communications, this paper proposes an iterative scheme combining time-domain N-continuous OFDM(TD-NC-OFDM) and serial peak cancellation(SPC). Based on the theory of projection onto convex sets(POCS), the effectiveness of the proposed scheme is proved, and the optimized time-frequency domain multicarrier waveforms are analyzed in terms of a balanced tradeoff between out-of-band spectral leakage and PAPR. Both theoretical analysis and simulation results show that the proposed scheme can jointly optimize both the PAPR and out-ofband radiation, with moderate computational complexity.

关键词： orthogonal frequency division multiplexing(OFDM) peak-to-average-power ratio(PAPR) spectral leakage

Multi-Agent Few-Shot Meta Reinforcement Learning for Trajectory Design and Channel Selection in UAV-Assisted Networks

在线全文

学校读者我要写书评

暂无评论

china Communications 2022年第4期19卷 166-176页

作者： Shiyang zhou yufan cheng Xia Lei Huanhuan Duan national key laboratory of {3. and technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China

Unmanned aerial vehicle(UAV)-assisted communications have been considered as a solution of aerial networking in future wireless networks due to its low-cost, high-mobility, and swift features. This paper considers a UAV-assisted downlink transmission,where UAVs are deployed as aerial base stations to serve ground users. To maximize the average transmission rate among the ground users, this paper formulates a joint optimization problem of UAV trajectory design and channel selection, which is NP-hard and non-convex. To solve the problem, we propose a multi-agent deep Q-network(MADQN) ***, the agents that the UAVs act as perform actions from their observations distributively and share the same reward. To tackle the tasks where the experience is insufficient, we propose a multi-agent meta reinforcement learning algorithm to fast adapt to the new tasks. By pretraining the tasks with similar distribution, the learning model can acquire general knowledge. Simulation results have indicated the MADQN scheme can achieve higher throughput than fixed allocation. Furthermore, our proposed multiagent meta reinforcement learning algorithm learns the new tasks much faster compared with the MADQN scheme.

关键词： UAV trajectory design channel selection MADQN meta reinforcement learning

基于深度强化学习的无人机间通信链路智能决策

在线全文

学校读者我要写书评

暂无评论

信号处理 2022年第7期38卷 1424-1433页

作者：周世阳程郁凡徐丰雷霞电子科技大学通信抗干扰技术国家级重点实验室四川成都611731 中国航空无线电电子研究所上海200241

由于无人机组网灵活、快速、低成本的特性,空中基站被视为在未来无线通信中有前景的技术。无人机集群可以通过相互协调和合作,完成的复杂任务,具有重大的研究和实用价值,而无人机间的高效通信是当下面临的重大挑战。为了在满足无人机间... 详细信息

由于无人机组网灵活、快速、低成本的特性,空中基站被视为在未来无线通信中有前景的技术。无人机集群可以通过相互协调和合作,完成的复杂任务,具有重大的研究和实用价值,而无人机间的高效通信是当下面临的重大挑战。为了在满足无人机间通信速率的前提下,尽可能节省发射功率,本文提出基于深度强化学习的集群方案和功率控制的智能决策算法。首先,本文设计了三种无人机集群方案,以对地面用户提供无缝的无线覆盖;然后,本文提出了基于深度Q网络(Deep Q-network)算法的集群方案和功率控制决策算法,用深度神经网络输出不同条件下联合决策的无人机集群方案和发射功率,并研究了重要性采样技术,提高训练效率。仿真结果表明,本文提出的深度强化学习算法能够正确决策无人机集群方案和发射功率,与不带强化学习的深度学习(Deep Learning Without Reinforcement Learning,DL-WO-RL)算法相比,用更低的发射功率满足无人机之间的通信速率要求,并且重要性采样技术能够缩短DQN算法的收敛时间。

关键词：深度强化学习智能决策无人机集群功率控制