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A Joint Feedback Bit and Power Allocation Strategy for Multi-cell Systems over Composite Fading Channels

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Chinese Journal of Electronics 2016年第3期25卷 541-550页

作者： MA Yue WANG Xin WANG Haihong GE Songhu wei jibo School of Electronic Science and Engineering National University of Defense Technology

This paper addresses the joint Feedback bit allocation(FBA) and Power allocation(PA)problem for a limited feedback coordinated multi-cell transmission system over composite fading channels. The Rayleigh/Lognormal fading channel is considered, and the effects of path loss and the macro-level correlation are also taken into account. A modified performance measure, referred to as the virtual sum rate is adopted to facilitate the analysis. The closed forms of the lower bound on virtual sum rate are derived over uncorrelated and correlated shadowed fading channels. Based on the lower bound, we then formulate an optimization problem of maximizing the virtual sum rate under constraints on the total number of feedback bits per MS and the total transmit power per BS. Considering the tight coupling between the FBA and the PA, we solve the optimization problem by solving an alternating sequence of FBA and PA subproblems using a coordinated ascent searching method. Numerical results show that the proposed strategy can converge in a few iterations and generally yield better performance than the conventional FBA schemes under composite fading channels.

关键词： Rayleigh/Lognormal fading Feedback bit allocation(FBA) Power allocation(PA) Limited feedback Multi-cell

AN IMPROVED MARKOV CHAIN MONTE CARLO METHOD FOR MIMO ITERATIVE DETECTION AND DECODING

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Journal of Electronics(China) 2008年第3期25卷 305-310页

作者： Han Xiang wei jibo Dept of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

Recently, a new soft-in soft-out detection algorithm based on the Markov Chain Monte Carlo (MCMC) simulation technique for Multiple-Input Multiple-Output (MIMO) systems is proposed, which is shown to perform significantly better than their sphere decoding counterparts with relatively low complexity. However, the MCMC simulator is likely to get trapped in a fixed state when the channel SNR is high, thus lots of repetitive samples are observed and the accuracy of A Posteriori Probability (APP) estimation deteriorates. To solve this problem, an improved version of MCMC simulator, named forced-dispersed MCMC algorithm is proposed. Based on the a posteriori variance of each bit, the Gibbs sampler is monitored. Once the trapped state is detected, the sample is dispersed intentionally according to the a posteriori variance. Extensive simulation shows that, compared with the existing solution, the proposed algorithm enables the markov chain to travel more states, which ensures a near-optimal performance.

关键词： List Sphere Decoding (LSD) Gibbs sampler Markov Chain Monte Carlo (MCMC)

Multiple symbol differential detection based on sphere decoding for unitary space-time modulation

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Science in China(Series F) 2009年第1期52卷 126-137页

作者： LI Ying wei jibo WANG Xin YU Quan School of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China China Electronic System Engineering Company Beijing 100039 China

Recently, a multiple symbol differential （MSD） sphere decoding （SD） algorithm for unitary spacetime modulation over quasi-static channel has been proved to achieve the performance of maximumlikelihood （ML） detection with relatively low complexity. However, an error floor occurs if the algorithm is applied over rapid-fading channels. Based on the assumption of continuous fading, a multiple symbol differential automatic sphere decoding （MSDASD） algorithm is developed by incorporating a recursive form of an ML metric into automatic SD （ASD） algorithm. Furthermore, two algorithms, termed as MSD approximate ASD （MSDAASD） and MSD pruning ASD （MSDPASD）, are proposed to reduce computational complexity and the number of comparisons, respectively. Compared with the existing typical algorithms, i.e., multiple symbol differential feedback detection （MS-DFD） and noncoherent sequence detection （NSD）, the performance of the proposed algorithms is much superior to that of MS-DFD and a little inferior to that of NSD, while the complexity is lower than that of MS-DFD in most cases and significantly lower than that of NSD.

关键词： differential unitary space-time modulation multiple symbol differential detection (MSDD) sphere decoding (SD)

A highly reliable encoding and decoding communication framework based on semantic information

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Digital Communications and Networks 2024年第3期10卷 509-518页

作者： Yichi Zhang Haitao Zhao Kuo Cao Li Zhou Zhe Wang Yueling Liu jibo wei College of Electronic Science and Technology National University of Defense TechnologyChangsha 410073China

Increasing research has focused on semantic communication,the goal of which is to convey accurately the meaning instead of transmitting symbols from the sender to the *** this paper,we design a novel encoding and decoding semantic communication framework,which adopts the semantic information and the contextual correlations between items to optimize the performance of a communication system over various *** the sender side,the average semantic loss caused by the wrong detection is defined,and a semantic source encoding strategy is developed to minimize the average semantic *** further improve communication reliability,a decoding strategy that utilizes the semantic and the context information to recover messages is proposed in the *** simulation results validate the superior performance of our strategies over state-of-the-art semantic coding and decoding policies on different communication channels.

关键词： Semantic information Semantic encoding method Context-based decoding method

Joint UAV trajectory and communication design with heterogeneous multi-agent reinforcement learning

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Science China(Information Sciences) 2024年第3期67卷 225-245页

作者： Xuanhan ZHOU Jun XIONG Haitao ZHAO Xiaoran LIU Baoquan REN Xiaochen ZHANG jibo wei Hao YIN College of Electronic Science and Technology National University of Defense Technology Systems Engineering Institute Academy of Military Sciences PLA

Unmanned aerial vehicles(UAVs) are recognized as effective means for delivering emergency communication services when terrestrial infrastructures are unavailable. This paper investigates a multiUAV-assisted communication system, where we jointly optimize UAVs' trajectories, user association, and ground users(GUs)' transmit power to maximize a defined fairness-weighted throughput metric. Owing to the dynamic nature of UAVs, this problem has to be solved in real time. However, the problem's non-convex and combinatorial attributes pose challenges for conventional optimization-based algorithms, particularly in scenarios without central controllers. To address this issue, we propose a multi-agent deep reinforcement learning(MADRL) approach to provide distributed and online solutions. In contrast to previous MADRLbased methods considering only UAV agents, we model UAVs and GUs as heterogeneous agents sharing a common objective. Specifically, UAVs are tasked with optimizing their trajectories, while GUs are responsible for selecting a UAV for association and determining a transmit power level. To learn policies for these heterogeneous agents, we design a heterogeneous coordinated QMIX(HC-QMIX) algorithm to train local Q-networks in a centralized manner. With these well-trained local Q-networks, UAVs and GUs can make individual decisions based on their local observations. Extensive simulation results demonstrate that the proposed algorithm outperforms state-of-the-art benchmarks in terms of total throughput and system fairness.

关键词： unmanned aerial vehicle (UAV) trajectory design resource allocation multi-agent deep reinforcement learning (MADRL) heterogeneous agents

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Extended context-based semantic communication system for text transmission

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Digital Communications and Networks 2024年第3期10卷 568-576页

作者： Yueling Liu Shengteng Jiang Yichi Zhang Kuo Cao Li Zhou Boon-Chong Seet Haitao Zhao jibo wei College of Electronic Science and Technology National University of Defense TechnologyChangsha410073China Department of Electrical and Electronic Engineering Auckland University of TechnologyAucklandNew Zealand

Context information is significant for semantic extraction and recovery of messages in semantic ***,context information is not fully utilized in the existing semantic communication systems since re-lationships between sentences are often *** this paper,we propose an Extended Context-based Semantic Communication(ECSC)system for text transmission,in which context information within and between sentences is explored for semantic representation and *** the encoder,self-attention and segment-level relative attention are used to extract context information within and between sentences,*** addition,a gate mechanism is adopted at the encoder to incorporate the context information from different *** the decoder,Transformer-XL is introduced to obtain more semantic information from the historical communication processes for semantic *** results show the effectiveness of our proposed model in improving the semantic accuracy between transmitted and recovered messages under various channel conditions.

关键词： semantic communication extended context Transformer-XL

WIDEBAND, INTELLIGENT AND INTEGRATED HF COMMUNICATIONS

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China Communications 2018年第9期15卷 I0002-I0004页

作者： jinlong wang shaoqian li jibo wei army engineering university of pla the ieee communications society nanjing chapter Universityof Electronic Science and Technology of China(uestc) ieee the national key laboratory of science on communications the department of communication engineering nudt

The high-frequency(HF)communication,commonly covering the frequency range between 3 and30MHz,is an effective and important long-distance communication *** the ionosphere as a natural high altitude reflector,trans-horizon HF radio transmission is possible with advantages such as high mobility,convenient deployment,strong survivability and

关键词：通讯 HF 宽带频率范围高周波反射镜电离层地平线

RATE ADAPTIVE PROTOCOL FOR MULTIRATE IEEE 802.11 NETWORKS

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Journal of Electronics(China) 2007年第3期24卷 289-295页

作者： Xi Yong Huang Qingyan wei jibo Zhao Haitao National University of Defense Technology Changsha 410073 China School of Telecommunication and Engineering Air Force Engineering University Xi＇an 710077 China

In this paper, a rate adaptive protocol AMARF (Adaptive Multirate Auto Rate Fallback) for multirate IEEE 802.11 networks is proposed. In AMARF, each data rate is assigned a unique success threshold, which is a criterion to judge when to switch a rate to the next higher one, and the success thresholds can be adjusted dynamically in an adaptive manner according to the running conditions, such as packet length and channel parameters. Moreover, the proposed protocol can be implemented by software without any change to the current IEEE 802.11 standards. Simulation result shows that AMARF yields significantly higher throughput than other existing schemes including ARF and its variants, in various running conditions.

关键词： IEEE 802.11 Rate adaptive Multirate

Toward Wisdom-Evolutionary and Primitive-Concise 6G:A New Paradigm of Semantic Communication Networks

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Engineering 2022年第1期8卷 60-73页

作者： Ping Zhang Wenjun Xu Hui Gao Kai Niu Xiaodong Xu Xiaoqi Qin Caixia Yuan Zhijin Qin Haitao Zhao jibo wei Fangwei Zhang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China Peng Cheng Laboratory Shenzhen 518066China Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China Key Laboratory of Trustworthy Distributed Computing and Service Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China The School of Electronic Engineering and Computer Science Queen Mary University of LondonLondon E14NSUK College of Electronic Science and Technology National University of Defense TechnologyChangsha 410073China School of Humanities Beijing University of Posts and TelecommunicationsBeijing 100876China

The sixth generation(6G)mobile networks will reshape the world by offering instant,efficient,and intelligent hyper-connectivity,as envisioned by the previously proposed Ubiquitous-X 6G *** hyper-massive and global connectivity will introduce tremendous challenges into the operation and management of 6G networks,calling for revolutionary theories and technological *** this end,we propose a new route to boost network capabilities toward a wisdom-evolutionary and primitive-concise network(WePCN)vision for the Ubiquitous-X 6G *** particular,we aim to concretize the evolution path toward the WePCN by first conceiving a new semantic representation framework,namely semantic base,and then establishing an intelligent and efficient semantic communication(IE-SC)network *** the IE-SC architecture,a semantic intelligence plane is employed to interconnect the semantic-empowered physical-bearing layer,network protocol layer,and application-intent layer via semantic information *** proposed architecture integrates artificial intelligence and network technologies to enable intelligent interactions among various communication objects in *** features a lower bandwidth requirement,less redundancy,and more accurate intent *** also present a brief review of recent advances in semantic communications and highlight potential use cases,complemented by a range of open challenges for 6G.

关键词： 6G Semantic information Semantic communication Intelligent communication