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Interference-Driven linear precoding in Multiuser MISO Downlink Cognitive Radio Network

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2012年第6期61卷 2531-2543页

作者： Khan, Faheem A. Masouros, Christos Ratnarajah, Tharmalingam Queens Univ Belfast Inst Elect Commun & Informat Technol Belfast BT3 9DT Antrim North Ireland

We consider linear precoding in the downlink of a multiuser multiple-input-single-output (MISO) overlay cognitive radio (CR) network, wherein a primary base station (PBS) and a cognitive base station (CBS) share the same frequency band to transmit to a number of primary users (PUs) and secondary users. Conventionally, linear precoding techniques in a CR network aim to limit or completely cancel interference to the PUs while achieving maximum downlink throughput of the CR system. In this paper, we investigate novel adaptive linear precoding techniques at the CBS to exploit the interference to the primary and secondary systems, instead of its cancellation, by exploring the potential of making use of interference energy when the interference between the two systems is mutually constructive on an instantaneous basis. By doing so, the received signal-to-noise ratio (SNR) is enhanced by the signal energy gleaned from the constructive interference. In this direction, constructive-interference-based adaptive linear precoding techniques are proposed for the CR network, assuming a simple zero-forcing precoder at the PBS and noncausal knowledge of the primary message at the CBS. The presented analysis and simulations show that the proposed precoding techniques outperform conventional techniques, as the CR transmission actively enhances the performance of the PUs through constructive interference while achieving significant throughput for its own transmission.

关键词： Cognitive radio (CR) linear precoding multiple-input-multiple-output (MIMO) overlay zero-forcing (ZF)

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Large System Analysis of linear precoding in Correlated MISO Broadcast Channels Under Limited Feedback

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IEEE TRANSACTIONS ON INFORMATION THEORY 2012年第7期58卷 4509-4537页

作者： Wagner, Sebastian Couillet, Romain Debbah, Merouane Slock, Dirk T. M. EURECOM F-06904 Sophia Antipolis France SUPELEC F-91190 Gif Sur Yvette France ST ERICSSON F-06560 Sophia Antipolis France

In this paper, we study the sum rate performance of zero-forcing (ZF) and regularized ZF (RZF) precoding in large MISO broadcast systems under the assumptions of imperfect channel state information at the transmitter and per-user channel transmit correlation. Our analysis assumes that the number of transmit antennas M and the number of single-antenna users K are large while their ratio remains bounded. We derive deterministic approximations of the empirical signal-to-interference plus noise ratio (SINR) at the receivers, which are tight as M, K -> infinity. In the course of this derivation, the per-user channel correlation model requires the development of a novel deterministic equivalent of the empirical Stieltjes transform of large dimensional random matrices with generalized variance profile. The deterministic SINR approximations enable us to solve various practical optimization problems. Under sum rate maximization, we derive 1) for RZF the optimal regularization parameter;2) for ZF the optimal number of users;3) for ZF and RZF the optimal power allocation scheme;and 4) the optimal amount of feedback in large FDD/TDD multiuser systems. Numerical simulations suggest that the deterministic approximations are accurate even for small M, K.

关键词： Broadcast channel (BC) limited feedback linear precoding multiuser (MU) systems random matrix theory (RMT)

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Sum Rate Maximization With Shortened Cyclic Prefix in a MIMO-OFDM System

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2018年第12期67卷 12416-12420页

作者： Kim, Namik Shin, Oh-Soon Lee, Kwang Bok Seoul Natl Univ Dept Elect & Comp Engn Seoul 08826 South Korea Seoul Natl Univ Inst New Media & Commun Seoul 08826 South Korea Soongsil Univ Sch Elect Engn Seoul 06978 South Korea Soongsil Univ Dept ICMC Convergence Technol Seoul 06978 South Korea

This correspondence paper addresses linear precoding design for sum rate maximization in low-latency orthogonal frequency-division multiplexing systems. In order to mitigate the overhead of cyclic prefix (CP) originating from shortened symbol duration for low-latency communications, 5G wireless systems need to adopt short CP lengths. As channel delay spread must be less than the CP length, we first derive the effective root-mean-square (RMS) delay spread and the achievable rate using the zero-forcing assumption. We construct a sum rate optimization problem for each user subject to delay spread constraints and then convert the problem into a solvable convex problem along with a semi-definite relaxation technique. The precoding matrix is finally obtained by solving optimization problems for all users. Numerical results reveal that the proposed scheme attains superior performance to the conventional sum rate optimization, as well as small RMS delay spread.

关键词： Sum rate maximization latency orthogonal frequency division multiplexing (OFDM) linear precoding

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Spatially Coupled LDPC Coding and linear precoding for MIMO Systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 2012年第12期E95B卷 3663-3670页

作者： Zhang, Zhonghao Xu, Chongbin Ping, Li City Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China

In this paper, we present a transmission scheme for a multiple-input multiple-output (MIMO) quasi-static fading channel with imperfect channel state information at the transmitter (CSIT). In this scheme, we develop a precoder structure to exploit the available CSIT and apply spatial coupling for further performance enhancement. We derive an analytical evaluation method based on extrinsic information transfer (EXIT) functions, which provides convenience for our precoder design. Furthermore, we observe an area property indicating that, for a spatially coupled system, the iterative receiver can perform error-free decoding even the original uncoupled system has multiple fixed points in its EXIT chart. This observation implies that spatial coupling is useful to alleviate the uncertainty in CSIT which causes difficulty in designing LDPC code based on the EXIT curve matching technique. Numerical results are presented, showing an excellent performance of the proposed scheme in MIMO fading channels with imperfect CSIT.

关键词： spatial coupling linear precoding MIMO LDPC code linear minimum mean-square error message passing detection EXIT chart

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Optimal precoding for full-duplex base stations under strongly correlated self-interference channels

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Frontiers of Information Technology & Electronic Engineering 2017年第6期18卷 808-816页

作者： Jun WANG Xiao-jie WEN Chuan HUANG Chao-jin QING College of Electrical and Information Engineering Southwest University for NationalitiesChengdu 610041China Beijing Institute of Satellite Information Engineering Beijing 100086China National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China School of Electrical and Information Engineering Xihua UniversityChengdu 610039China

We study the optimal precoding for a full-duplex (FD) system, where one FD multi-antenna base station (BS) respectively transmits to and receives from two half-duplex single-antenna mobile users (MUs) on the same time slot and frequency band. At the FD BS, the received signal from the desired MU is severely affected by the extremely strong self-interference (SI) from its transmit antennas to the receive antennas. In the presence of residual SI after imperfect SI cancellation, the downlink transmission rate maximization problem subject to a targeted uplink rate is formulated as a non-convex optimization problem to characterize the achievable rate region for the considered system. Considering the case in which the SI channel is strongly correlated, the above problem is transformed into a convex problem by exploiting the rank-one property of the SI channel, which can be solved efficiently. Finally, numerical results validate the effectiveness of the proposed scheme.

关键词： linear precoding Full-duplex Achievable rate region Strongly correlated self-interference channel

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linear precoding Based Iterative Detection Algorithm in Asynchronous MI MO-OFDM Systems

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China Communications 2012年第4期9卷 63-70页

作者： Mo Taofu Liu Tian Shao Shihai Tang Youxi National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731P.R.China

In asynchronous Multiple-Input-Multiple-Output Orthogonal Frequency Division Multiplexing(MIMO-OFDM) over the selective Rayleigh fading channel,the performance of the existing linear detection algorithms improves slowly as the Signal Noise Ratio (SNR) *** improve the performance of asynchronous MIMO-OFDM,a low complexity iterative detection algorithm based on linear precoding is proposed in this *** the transmitter,the transmitted signals are spread by precoding matrix to achieve the space-frequency diversity gain,and low complexity iterative Interference Cancellation(IC) algorithm is used at the receiver,which relieves the error propagation by the precoding *** performance improvement is verified by *** the condition of 4 transmitting antennas and 4 receiving antennas at the BER of 10-4,about 6 dB gain is obtained by using our proposed algorithm compared with traditional algorithm.

关键词： asynchronous MIMO-OFDM linear precoding iteration linear detection

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Enhanced Outage Performance With Adaptive linear precoding in Cognitive Radio Downlink

Enhanced Outage Performance With Adaptive Linear Precoding i...

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IEEE International Conference on Communications (ICC)

作者： Khan, F. A. Masouros, C. Ratnarajah, T. Queens Univ Belfast ECIT Belfast BT3 9DT Antrim North Ireland

ISBN: (纸本)9781457720536

In this paper, we investigate the outage performance of interference aided adaptive linear precoding in the downlink of a multiuser multiple-input-single-output (MISO) overlay cognitive radio (CR) network. While previous research studies on linear precoding techniques in CR network aim to limit or completely cancel the interference to the primary users while achieving maximum downlink throughput of the CR system, we here make use of adaptive linear precoding at the cognitive base station (CBS) to exploit the interference to the primary and the secondary systems. We show by analysis and simulations that the outage performance of the proposed precoding technique is significantly enhanced in comparison to the conventional techniques.

关键词： Cognitive radio overlay linear precoding zero-forcing outage capacity

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Low-Complexity MIMO precoding for Finite-Alphabet Signals

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第7期16卷 4571-4584页

作者： Wu, Yongpeng Ng, Derrick Wing Kwan Wen, Chao-Kai Schober, Robert Lozano, Angel Tech Univ Munich Inst Commun Engn D-80333 Munich Germany Shanghai Jiao Tong Univ Shanghai Key Lab Nav & Locat Based Minhang 200240 Peoples R China Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia Natl Sun Yat Sen Univ Inst Commun Engn Kaohsiung 804 Taiwan Univ Erlangen Nurnberg Inst Digital Commun Cauerstr 7 D-91058 Erlangen Germany Univ Pompeu Fabra Barcelona 08018 Spain

This paper investigates the design of precoders for single-user multiple-input multiple-output (MIMO) channels, and, in particular, for finite-alphabet signals. Based on an asymptotic expression for the mutual information of channels exhibiting line-of-sight components and rather general antenna correlations, precoding structures that decompose the general channel into a set of parallel subchannel pairs are proposed. Then, a low-complexity iterative algorithm is devised to maximize the sum mutual information of all pairs. The proposed algorithm significantly reduces the computational load of existing approaches with only minimal loss in performance. The complexity savings increase with the number of transmit antennas and with the cardinality of the signal alphabet, making it possible to support values thereof that were unmanageable with existing solutions. Most importantly, the proposed solution does not require instantaneous channel state information (CSI) at the transmitter, but only statistical CSI.

关键词： Finite alphabet inputs linear precoding multiple-input multiple-output (MIMO) replica method

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On Integer-Forcing precoding for the Gaussian MIMO Broadcast Channel

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第7期16卷 4476-4488页

作者： Silva, Danilo Pivaro, Gabriel Fraidenraich, Gustavo Aazhang, Behnaam Univ Fed Santa Catarina Dept Elect & Elect Engn BR-88040900 Florianopolis SC Brazil Univ Estadual Campinas Dept Commun BR-13083852 Campinas SP Brazil Natl Inst Telecommun Radiocommun Reference Ctr BR-37540000 Santa Rita Do Sapucai Brazil Rice Univ Dept Elect & Comp Engn Houston TX 77005 USA

Integer-forcing (IF) precoding, also known as downlink IF, is a promising new approach to communication over multiple-input multiple-output (MIMO) broadcast channels. Inspired by the integer-forcing linear receiver for multiple-access channels, it generalizes linear precoding by inducing an effective channel matrix that is approximately integer, rather than approximately identity. Combined with lattice encoding and a pre-inversion of the channel matrix at the transmitter, the scheme has the potential to outperform any linear precoding scheme, despite enjoying similar low complexity. In this paper, a specific IF precoding scheme, called diagonally scaled exact IF (DIF), is proposed and shown to achieve maximum spatial multiplexing gain. For the special case of two receivers, in the high SNR regime, an optimal choice of parameters is derived analytically, leading to an almost closed-form expression for the achievable sum rate. In particular, it is shown that the gap to the sum capacity is upper bounded by 0.27 bits for any channel realization. For general SNR, a regularized version of DIF (RDIF) is proposed. Numerical results for two receivers under Rayleigh fading show that RDIF can achieve performance superior to optimal linear precoding and very close to the sum capacity.

关键词： Multiuser MIMO broadcast channel linear precoding beamforming compute-and-forward integer-forcing

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Joint linear precoding and Nonbinary LDPC Coding for Underwater Acoustic OFDM

Joint Linear Precoding and Nonbinary LDPC Coding for Underwa...

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MTS/IEEE Oceans Conference

作者： Wan, Lei Hurst, Shae Wang, Zhaohui Zhou, Shengli Shi, Zhijie Roy, Sumit Univ Connecticut Dept Elect & Comp Engn Storrs CT 06269 USA Univ Washington Dept Elect Engn Seattle WA 98195 USA Univ Connecticut Dept Comp Sci & Engn Storrs CT 06269 USA

ISBN: (纸本)9781467308298;9781467308304

Both channel coding over a finite field and linear precoding over a complex field can improve the system performance in wireless fading channels. In this paper, we investigate the potential benefit of linear precoding in a nonbinary LDPC coded underwater acoustic OFDM system. Real precoders of small sizes are selected in different setups, in order to avoid any complexity increase at the receiver. Simulations and emulated experimental results demonstrate the benefits of linear precoding, particularly when the receiver has a small number of hydrophones.

关键词： Underwater acoustic communications linear precoding nonbinary LDPC coding diversity

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