曹志刚
研究领域包括卫星通信、宽带移动通信、通信理论等
个性化签名
- 姓名:曹志刚
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学术头衔:
博士生导师
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学科领域:
发酵工程
- 研究兴趣:研究领域包括卫星通信、宽带移动通信、通信理论等
曹志刚教授1962年毕业于清华大学无线电电子学系,获优秀毕业生金质奖章。1984至1986年美国斯坦福大学访问学者、副研究员。1997年香港科技大学访问学者。
现任清华大学电子工程系教授、博士生导师、微波与数字通信国家重点实验室副主任、教育部远程教育专家委员会副主任、总装航天装备标准化委员会委员、中国教育电视台专家组长、国家政府采购网专家、中国通信学会会士、中国通信学会学术工作委员会副主任、纽约科学院member、中国电子学会高级会员、IEEE高级会员、日本电子信息通信工程师学会(IEICE)海外会员、北京电信通信学会理事、中国卫星通信广播电视用户协会常务理事、<电子学报>副主编、<Chinese Journal of Electronics>、
先后主持和参加数据传输、脉冲编码调制、网格编码调制、语音增强、全数字解调、卫星通信、航空遥感卫星传输系统、远程教育技术、宽带无线通信、抗噪声语音识别等领域的多项研究,获国家科学大会、电子工业部一等奖、国家教委三等奖和教育部二等奖、北京市科技进步二等奖、国防科工委三等奖、军队科技进步二等奖、山东省一等奖等八项奖励。持专利13项。获政府特殊津贴。指导的研究生中已有20余名获博士学位,50余名获硕士学位,其中5人获清华大学优秀博士论文和硕士论文,指导的一名博士生获2003年全国优秀博士论文奖,另一名获2005年全国优秀博士论文奖提名。合作著译五部:"现代通信原理"、"现代数字通信技术"、"语音信号数字处理"、"计算机控制的测量与仪器"(译)和"语音信号数字处理"(译)。其中"现代通信原理"(第一作者)一书获一九九六年第三届全国电子类优秀教材一等奖,已印刷超过10万册。参加王大珩等主编的《高技术词典》的编撰工作,任通信技术领域编委会主任。发表论文340余篇,其中被SCI收录论文36篇,EI收录论文150余篇。 目前的研究领域包括卫星通信、宽带移动通信、通信理论等。
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主页访问
3958
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0
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成果阅读
1798
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成果数
19
【期刊论文】Spread-spectrum sequence estimation for DSSS signal in non-cooperative communication systems
曹志刚, Y. Zhan, Z. Cao and J. Lu
IEE Proc.-Commun., Vol. 152, No.4, August 2005,-0001,():
-1年11月30日
An innovative and effective algorithm is proposed to estimate the spread-spectrum sequence of a direct spread-spectrum sequence (DSSS) signal in non-cooperative communication systems. In particular, a measurement function, which is used for sequence synchronisation, and a detection statistic, which is for sequence estimation chip by chip, are developed based on the idea of correlation. Only linear complex addition and multiplication are required for the implementation of the algorithm. Theoretical analysis and computer simulations verify the effectiveness of the algorithm.
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【期刊论文】Flexible Construction of Irregular Partitioned Permutation LDPC Codes With Low Error Floors
曹志刚, Jingyu Kang, Pingyi Fan, Member, IEEE, and Zhigang Cao, Senior Member
IEEE COMMUNICATIONS LETTERS, VOL. 9, NO.6, JUNE 2005,-0001,():
-1年11月30日
Irregular partitioned permutation (IPP) low-density parity-check (LDPC) codes have been recently introduced to facilitate hardware implementation of belief propagation (BP) decoders. In this letter, we present a new method to construct IPP LDPC codes with great flexibility in the selection of code parameters. Meanwhile, small stopping sets are avoided in the code construction, thus good error floor performance can be achieved.
Error floor,, low-density parity-check codes,, permutation matrix,, stopping set.,
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【期刊论文】Space-Time Turbo Multiuser Detection for Coded MC-CDMA
曹志刚, Junqiang Li, Khaled Ben Letaief, Fellow, IEEE, and Zhigang Cao, Senior Member
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 4, NO.2, MARCH 2005,-0001,():
-1年11月30日
The system capacity and performance of multicarrier code-division multiple-access (MC-CDMA) communication systems can be significantly enhanced by jointly employing MAP-based multiuser detection (MUD) and channel decoding techniques. In this paper, a group-oriented soft iterative MUD based on the combination of smart antennas and iterative MAP-based MUD is presented. The proposed method is featured as a novel technique for further increasing the system capacity and performance. In this method, all the users are first grouped into several groups according to their impinging direction of arrivals (DOAs). All users with similar DOAs are classified into the same group and then low-complexity MAP-based iterative MUD is employed in each group. Because spatial filtering cannot suppress all the interference between the groups, interference cancellation among the groups is used prior to MUD within each group. It is shown that the proposed group-oriented soft iterative MUD algorithm can significantly reduce the computational complexity compared with the conventional optimal MAP-based MUD schemes. It is also demonstrated that the performance of the proposed algorithm can approach that of a single-user coded MC-CDMA system with an antenna array in additive white Gaussian noise and frequency selective fading channels.
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【期刊论文】Non-binary type-II HARQ and its application to an adaptive system
曹志刚, Lijun Zhang, Victor O. K. Li and Zhigang Cao, n, y
INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS Int. J. Commun. Syst. 2005, 18: 97-117,-0001,():
-1年11月30日
Non-binary type-II hybrid ARQ (HARQ), which combines shortened Reed–Solomon (RS) code with ARQ, is proposed. Its throughput is obtained by extending Lin and Yu’s analysis of binary type-II HARQ. The reliability and average delay are also obtained. The analytical results show that non-binary HARQ outperforms its binary counterpart in throughput, reliability and average delay when proper RS codes are selected. Non-binary HARQs are applied adaptively in a cellular phone system with uniformly distributed mobile terminals (MTs). MTs switch adaptively between two different hybrid schemes according to the average SNR of the received signals. The adaptive parameters include the size of the modulation constellation, the error-correction coding and their joint adaptation. Numerical results show that the adaptive scheme always outperforms its non-adaptive counterparts, and the adaptive modulation scheme is superior to adaptive coding and the joint adaptation scheme when the implementation complexity is a limiting factor. Robustness analysis shows that introducing a mixed modulation scheme in addition to QPSK and 8PSK in the adaptive modulation scheme is unnecessary, and HARQ with adaptive modulation is insensitive to deviations from the optimal threshold, thus facilitating its implementation. Copyright
automatic-repeat-request (, ARQ), , non-binary type-II HARQ, adaptive modulation, adaptive coding, robustness analysis
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64浏览
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【期刊论文】Dynamic Spatial Subchannel Allocation With Adaptive Beamforming for MIMO/OFDM Systems
曹志刚, Ya-Han Pan, Khaled Ben Letaief, Fellow, IEEE, and Zhigang Cao, Senior Member
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 3, NO.6, NOVEMBER 2004,-0001,():
-1年11月30日
Orthogonal frequency division multiplexing (OFDM) has been widely regarded as an effective modulation technique for mitigating the effects of intersymbol interference in a frequency selective fading channel and for providing reliable high-data-rate transmission over wireless links. Adaptive antenna arrays at the base and mobile stations can achieve further increases in system's capacity and bandwidth efficiency, as well as in quality-of-service improvement in conventional OFDM systems. The conventional adaptive antenna-arrays-based OFDM systems always use the subcarriers characterized by the largest eigenvalues to transmit the OFDM block symbols. In this paper and in contrast to previous work, we propose dynamic spatial subchannel allocation with adaptive beamforming for broadband OFDM wireless transmission systems. The proposed system adaptively selects the eigenvectors associated with the relatively large spatial subchannel eigenvalues to generate the beamforming weights at the mobile and base stations and then dynamically assigns the corresponding best spatial subchannels to transmit the OFDM block symbols. It is shown that the proposed system can achieve better performance than an adaptive antenna-arrays-based OFDM system without dynamic spatial subchannel allocation over multipath fading channels. Simulation results also reveal that the proposed system is far less susceptible to feedback delay in rapid time-varying channels and a little more sensitive to channel estimation errors than conventional adaptive antenna-arrays-based OFDM systems. The performance of the proposed system combined with adaptive modulation is also considered.
Adaptive antenna arrays,, adaptive modulation,, dynamic spatial subchannel allocation,, joint transmit and receive beamforming,, multiple-input multiple-output (, MIMO), ,, orthogonal frequency-division multiplexing (, OFDM), .,
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【期刊论文】SNR Estimation Using Gibbs Sampler
曹志刚, Zhigang CAO†a), Member, Yafeng ZHAN†∗, and Zhengxin MA†, Nonmembers
IEICE TRANS. COMMUN., VOL.E87-B, NO.10 OCTOBER 2004,-0001,():
-1年11月30日
This paper proposes a SNR estimation scheme based on Gibbs sampler [1]-[6]. This scheme can estimate SNR using a very short received sequence, and does not require any prior information of the transmitted symbol. Compared with the existing estimators, the performance of this method is better when real SNR is larger than 5 dB in both single path channel and multi-path channel.
SNR estimation,, Gibbs sampler,, Monte Carlo methods
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【期刊论文】Reduced-Complexity MAP-Based Iterative Multiuser Detection for Coded Multicarrier CDMA Systems
曹志刚, Junqiang Li, Khaled Ben Letaief, Fellow, IEEE, and Zhigang Cao, Senior Member
IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 52, NO.11, NOVEMBER 2004,-0001,():
-1年11月30日
In recent years, combining multiuser detection (MUD) and channel decoding has received considerable attention. The maximum a posteriori (MAP) criterion-based iterative multiuser detector greatly improves the system performance and can approach the performance of single-user coded systems. However, its complexity increases exponentially with the number of users and can become prohibitive for systems with a medium-to-large number of users. In this paper, a reduced complexity MAP-based iterative MUD based on the use of a soft sensitive bits algorithm is proposed for coded multicarrier code-division multiple-access systems. It is shown that it can greatly reduce the computational complexity with a minimal penalty in performance compared to the conventional optimal scheme.
Coded multicarrier code-division multiple access (, MC-CDMA), ,, iterative multiuser detection (, MUD), ,, maximum a posteriori (, MAP), detection,, turbo processing.,
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55浏览
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曹志刚, Dan Zhang, Pingyi Fan and Zhigang Cao, Senior Member, IEEE
IEEE Transactions on Consumer Electronics, Vol. 50, No.1, FEBRUARY 2004,-0001,():
-1年11月30日
Narrowband interference (NBI) is one of the mostimportant problems in an OFDM system, which not only degrades the signal performance on the overlapped subcarriers, but also affects the signal performance on the nearby subchannels due to the spectral leakage effect of DFT demodulation at the receiver. In this paper, we consider the NBI problem caused by narrow band digital communication systems, and propose a novel NBI cancellation method. We consider the NBI reconstruction problem including NBI central frequency and its bandwidth estimation. Simulation results show that this method can achieve about 6dB signal to interference plus noise ratio (SINR) gain if the interference bandwidth is about twice of that OFDM bins and the system SINR is about 0 dB. As the bandwidth of NBI decreases, more SINR gain will be obtained. Meanwhile, We also consider the system implementation problem, it has shown that its implementation complexity is not high based on the current digital signal processing techniques. If zoom FFT is employed in our system, the calculation complexity can be reduced considerably1.
narrowband interference cancellation,, OFDM,, WLAN
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【期刊论文】A Reduced-Complexity Maximum-Likelihood Method for Multiuser Detection
曹志刚, Junqiang Li, Khaled Ben Letaief, Fellow, IEEE, and Zhigang Cao, Senior Member
IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 52, NO.2, FEBRUARY 2004,-0001,():
-1年11月30日
Multiuser or joint detection has recently been receiving significant research interest because of its potential for the significant increase in system capacity and performance. Among the conventional multiuser detection schemes such as the minimum mean-squared error and successive interference cancellation-based ones, maximum-likelihood multiuser detection has the best system performance. However, the complexity of maximum-likelihood detection (MLD) increases exponentially in the number of users and constellation size. In this paper, a low-complexity MLD scheme based on the use of a sensitive-bits algorithm is proposed. It is demonstrated that the proposed method can greatly reduce the computational complexity with a minimal penalty in performance compared with the exhaustive optimal MLD scheme.
Maximum-likelihood detection (, MLD), ,, multiuser detection,, space-division multiple access (, SDMA), ,, space-division multiplexing (, SDM), ,, wireless communication systems.,
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曹志刚, Guoping Fan, Pingyi Fan*† and Zhigang Cao
Wterl. Commun. Mob. Comput, 2004, 4: 475-482,-0001,():
-1年11月30日
A differential detection scheme for transmit diversity was proposed by Tarokh. which can achieve full diversity order without the requirement to estimate the channel state at the receiver. This paper investigates the potential of using multiple receive antennas for differential space time coded MPSK signals over correlated Nakagami fading channels. We also investigate the effect of the carrier frequency offset (CFO) and channel correlation on its performance and present some results on its maximal tolerable frequency offsets for different MPSK signals. The results have shown that the differential encoding transmit diversity is very robust to the CFO and channel correlation. Copyright
transmit diversity, differential detection, carrier recovery, bit error rate, wireless communications
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