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A Low Complexity Heterodyne Multiband MIMO Receiver with Baseband Automatic Gain Control

IEICE TRANSACTIONS ON COMMUNICATIONS 2013年第12期E96B卷 3124-3134页

作者： Ohta, Tomoya Denno, Satoshi Morikura, Masahiro Kyoto Univ Grad Sch Informat Kyoto 6068501 Japan Okayama Univ Grad Sch Nat Sci & Technol Okayama 7008530 Japan

This paper proposes a novel heterodyne multiband multiple-input multiple-output (MIMO) receiver with baseband automatic gain control (AGC) for cognitive radios. The proposed receiver uses heterodyne reception implemented with a wide-passband band-pass filter in the radio frequency (RF) stage to be able to receive signals in arbitrary frequency bands. Even when an RF Hilbert transformer is utilized in the receiver, image-band interference occurs due to the imperfection of the Hilbert transformer. In the receiver, analog baseband AGC is introduced to prevent the baseband signals exceeding the voltage reference of analog-to-digital converters (ADCs). This paper proposes a novel technique to estimate the imperfection of the Hilbert transformer in the heterodyne multiband MIMO receiver with baseband AGC. The proposed technique estimates not only the imperfection of the Hilbert transformer but also the AGC gain ratio, and analog devices imperfection in the feedback loop, which enables to offset the imperfection of the Hilbert transformer. The performance of the proposed receiver is verified by using computer simulations. As a result, the required resolution of the ADC is 9 bits in the proposed receiver. Moreover, the proposed receiver has less computational complexity than that with the baseband interference cancellation unless a frequency band is changed every 9 packets or less.

关键词： cognitive radio heterodyne multiband receiver baseband automatic gain control multiple-input multiple-output analog devices imperfection in a feedback loop

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Early Eviction Technique for Low-Complexity Soft-output MIMO Symbol Detection Based on Dijkstra's Algorithm

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2013年第11期E96A卷 2302-2305页

作者： Kim, Tae-Hwan Korea Aerosp Univ Sch Elect Telecommun & Comp Engn Goyang Si 412791 Gyungui Do South Korea

This letter presents a technique to reduce the complexity of the soft-output multiple-input multiple-output symbol detection based on Dijkstra's algorithm. By observing that the greedy behavior of Dijkstra's algorithm can entail unnecessary tree-visits for the symbol detection, this letter proposes a technique to evict non-promising candidates early from the search space. The early eviction technique utilizes layer information to determine if a candidate is promising, which is simple but effective. When the SNR is 30 dB for 6 x 6 64-QAM systems, the average number of tree-visits in the proposed method is reduced by 72.1% in comparison to that in the conventional Dijkstra's algorithm-based symbol detection without the early eviction.

关键词： multiple-input multiple-output soft output sphere decoding maximum-likelihood detection tree search

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Achievable Spatial Throughput in Multi-Antenna Cognitive Underlay Networks with Multi-Hop Relaying

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2013年第8期31卷 1543-1558页

作者： Zaidi, Syed Ali Raza Ghogho, Mounir McLernon, Des C. Swami, Ananthram Univ Leeds Sch Elect & Elect Engn Leeds W Yorkshire England Int Univ Rabat Rabat Morocco US Army Res Lab Adelphi MD USA

In this article, we quantify the achievable spatial throughput of a multi-antenna Poisson cognitive radio network (CRN) collocated with a Poisson multi-antenna primary network. CR users employ Slotted-ALOHA medium access control. The success probability (SP) of a primary link is quantified in the presence of the secondary and primary interferers. It is demonstrated that two fold gains are experienced by employing multiple antennas at primary, i.e., (i) the fixed high desired SP threshold is met;(ii) CRs can also be accommodated without QoS deterioration. Further in this paper, the maximum permissible medium access probability (MAP) for CRN is derived from the link SP and primary users QoS constraint. The impact of the number of antennas and modulation employed at the primary on the permissible MAP of the CRN is also explored. Assuming that CR users employ multi-hop communication, QoS aware relaying with a radian sector forwarding area is studied. The average forward progress (AFP) and isolation probability for a CR user with QoS based connectivity is characterized under the permissible MAP. The spatial throughput for the CRN is quantified by the analysis of the AFP and the permissible MAP. It is shown that there exists an optimal MAP which maximizes the spatial throughput of the CRN. This optimal MAP is coupled with the permissible MAP, density of users, number of antennas and modulation schemes employed in both primary and secondary networks. Lastly, a few important design questions are investigated for multi-hop MIMO underlay CRNs.

关键词： Cognitive radio Poisson point process stochastic geometry multiple-input multiple-output ad-hoc underlay isolation

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Interference alignment for MIMO cognitive networks: a complex FDPM-based subspace tracking approach

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INTERNATIONAL JOURNAL OF EMBEDDED SYSTEMS 2013年第3期5卷 166-174页

作者： Zhu, Bin Ge, Jianhua Li, Jing Shi, Xiaoye Huang, Yunxia Xidian Univ State Key Lab Integrated Serv Networks 2 South Taibai Rd Xian 710071 Shaanxi Peoples R China

Interference alignment (IA) for multiple-input multiple-output (MIMO) cognitive networks is considered by modelling the unlicensed secondary transmitter-receiver pairs which coexist with the licensed multi-antenna primary user as a K-user MIMO interference channel. Starting from investigating the constraint conditions of IA scheme in MIMO cognitive networks, a practical IA algorithm is developed by using a subspace tracking approach based on the complex fast data projection method (FDPM). In the proposed algorithm, first, each secondary transmitter aligns its transmitted signal into the null space of the channel matrix from itself to the primary user without causing any interference to the primary user. Then secondary transmitters and receivers, requiring no channel knowledge of secondary networks, alternately design the precoding and postprocessing matrices through a training period which exploits the complex FDPM-based minor subspace tracking, thus eliminating interference among secondary users. Moreover, the case where secondary transmitters have partial knowledge of channels from themselves to the primary user is also discussed. Simulation results reveal that the proposed algorithm can achieve a high sum rate performance while requiring low computational complexity.

关键词： interference alignment IA subspace tracking fast data projection method FDPM multiple-input multiple-output MIMO cognitive networks sum rate

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Decorrelation MIMO Receiver for Block Fading Channels

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IEEE COMMUNICATIONS LETTERS 2013年第11期17卷 2112-2115页

作者： Mao, Xuehong Chen, Rong-Rong She, Huajun Farhang-Boroujeny, Behrouz Univ Utah ECE Salt Lake City UT USA

In this paper, we propose a novel decorrelation receiver for multiple-input multiple-output (MIMO) block fading channels. The proposed design breaks the correlation between soft-decision-directed channel estimation (SCE) and data detection, and thus improves the performance of existing receivers that do not take such correlation into account. Computer simulations confirm that the decorrelation receiver yields excellent performance when applied to the Markov Chain Monte Carlo (MCMC) MIMO detector and the soft minimum mean-square-error (MMSE) MIMO detector.

关键词： Channel estimation iterative detection Markov chain Monte Carlo multiple-input multiple-output

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A reconfigurable antenna using varactor diode for LTE MIMO applications

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2013年第5期55卷 1141-1145页

作者： Yoon, Cheol Hwang, Sun-Gook Lee, Gi-Chan Kim, Woo-Su Lee, Hwa-Choon Park, Hyo-Dal Inha Univ Dept Elect Engn Inchon 402751 South Korea KEIT Seoul 135080 South Korea Chodang Univ Dept Informat & Commun Engn Muan Gun 534800 Cheon Nam South Korea

In this article, a mobile embedded antenna having tunable capacitance is proposed and the validity of the proposed solution was proved through design, fabrication, and *** antenna can be applied to long-term evolution (LTE) as well as DCS/PCS/WCDMA bands being currently used. Antennas for the 4G mobile service are required to expand its bandwidth so that it includes both LTE band and other service bands. However, it is hard to obtain low-band characteristic due to the limited space for antenna in terminals. The proposed antenna consists of two planar inverted F antennas that are orthogonally arranged. Two radiators should be designed to have equal or enhanced isolation (S21) of lower than 15 dB. To meet this requirement, a varactor diode SMV2109 (skyworks corp.) was used to make the operation frequency of low-band tunable. With the optimized parameters, the antenna was fabricated and measured and the results have been compared with the simulated result. The antenna satisfied with operation frequency and performance for both low-band and high-band, and measured performance of the antenna fabricated with optimized parameters is compared and analyzed with the simulation results. (c) 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:11411145, 2013;View this article online at ***. DOI 10.1002/mop.27479

关键词： reconfigurable antenna varactor diode long-term evolution multiple-input multiple-output

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Interference management strategy for multiuser two-way relay networks

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INTERNATIONAL JOURNAL OF EMBEDDED SYSTEMS 2013年第3期5卷 175-180页

作者： Wang, Yong Yang, Liu Ai, Yun Li, Hui Zhang, Yueyu Li, Fengrong Xidian Univ State Key Lab Integrated Serv Networks 106 Mailbox Xian Shaanxi Peoples R China Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Key Lab Wireless Sensor Network & Commun Shanghai 200050 Peoples R China

We investigate the interference management strategy for multiuser two-way transmission network where multiple pairs of users communicate with their pre-assigned partners, with assistance of an amplify-and-forward relay. The design objective is that the tradeoff between the efficiency and reliability could be achieved as much as possible. By taking advantage of the signal space alignment technique to cancel the multi-user interference, all users can transmit massages to the relay simultaneously over the same channel resource. And a new multiple-input multiple-output (MIMO) precoding matrix is designed to reduce the decoding complexity. Simulation result shows the average sum rate performance of the proposed system, and the achievable degrees of freedom can outperform MU-MIMO scheme and TDMA scheme.

关键词： multiple-input multiple-output MIMO precoding embedded systems two-way relay multiuser

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multiple Relay Selection for Delay-Limited Applications

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IEEE WIRELESS COMMUNICATIONS LETTERS 2013年第6期2卷 675-678页

作者： Alsharoa, Ahmad Abediseid, Walid Alouini, Mohamed-Slim KAUST Comp Elect & Math Sci & Engn CEMSE Div Thuwal Makkah Province Saudi Arabia

A multiple relay selection system model that implements the decode-and-forward mode is investigated. All communication nodes are assumed to be equipped by multiple antennas. Furthermore, lattices space-time coded multiple-input multiple-output half duplex channel is applied. The main goal is to increase the throughput of the system by selecting multiple number of relays. The selection criteria depends on the maximum decoding delay at relays where the system implements a decoding time-out algorithm at each relay. This leads to a significant saving in the overall system power consumptions and attempts to solve the relays synchronization problem. All results are presented using numerical simulations.

关键词： multiple-input multiple-output lattices space-time multiple relay selection

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A Novel Optical Wireless MIMO Architecture and Its Application

A Novel Optical Wireless MIMO Architecture and Its Applicati...

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International Conference on Computing, Networking and Communications (ICNC)

作者： Niu, Mingbo Cheng, Julian Holzman, Jonathan F. Univ British Columbia Sch Engn Kelowna BC V1V 1V7 Canada

ISBN: (纸本)9781467300094

A novel coherent optical multiple-input multiple-output architecture is proposed for wireless communication links to mitigate atmospheric turbulence effects. Transmitter optical signals operate at distinct carrier frequencies to allow the received optical signals to be separately processed. The accumulated phase noise in each transmission branch can be independently compensated electronically. Based on the proposed architecture, several popular diversity combining techniques are considered for system performance evaluation. The presented results demonstrate substantial error performance improvement over a single-input single-output coherent optical wireless link.

关键词： multiple-input multiple-output optical communications optical scintillation phase noise

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Adaptive Parameter Estimation in MIMO Radar

Adaptive Parameter Estimation in MIMO Radar

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International Conference on Mechatronic Sciences, Electric Engineering and Computer (MEC)

作者： Gao, Zhifeng Peng, Xiyuan Peng, Yu Harbin Inst Technol Automat Test & Control Inst Harbin 150006 Peoples R China

ISBN: (纸本)9781479925650

In multiple-input multiple-output radar, independent waveforms are transmitted from different antennas, and the target parameters are estimated via the linearly independent echoes from different targets. Several adaptive approaches are directly applied to target angle and target amplitude estimation, including Capon, APES (amplitude and phase estimation). The CCA (canonical correlation analysis) approach is first proposed to estimate target locations which has high peak amplitudes, then a gradient-based algorithm is presented to improve the target angle estimation accuracy based on Capon approach which has a high resolution. With an initial angle, the angle sequence is iteratively updated with adaptive steps and converges to local peaks which indicate the target locations. Simulations show that the target angle accuracy is improved, and the common DOA (direction-of-arrive) problem is avoided.

关键词： parameter estimation multiple-input multiple-output gradient-based adaptive step

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