Noniterative Coordinated Beamforming for Multiuser MIMO Systems With Limited Feedforward

Soriano‐Equigua, Leonel; García, Jaime Sánchez; Flores-Troncoso, Jorge; Heath, Robert W.

doi:10.1109/lsp.2011.2171483

Cited by 6 publications

(8 citation statements)

References 11 publications

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“…Besides the above shortcomings of existing studies concerning the radar functionality of OFDM, a significant challenge involving the communications aspect of OFDM in dual-functional scenarios pertains to the availability of limited feedforward channel from the DFRC transceiver to the communications receiver [32], [33], [34], which, to the best of authors' knowledge, has not been addressed in the existing DFRC research. The key consideration is that DFRC waveforms can be designed flexibly at the transceiver side in line with the requirements of radar and communications subsystems; nevertheless, such waveforms become part of the effective channel between the transmitter and the receiver, which comprises transmit waveform (i.e., subcarrier powers) and communication channel gains.…”

Section: A Background and Motivationmentioning

confidence: 99%

“…The key consideration is that DFRC waveforms can be designed flexibly at the transceiver side in line with the requirements of radar and communications subsystems; nevertheless, such waveforms become part of the effective channel between the transmitter and the receiver, which comprises transmit waveform (i.e., subcarrier powers) and communication channel gains. In order for the receiver to be able to decode transmit symbols, DFRC waveform information should thus be conveyed to the receiver side over a separate, possibly low-rate, feedforward/control channel [32], [34]. Therefore, DFRC waveform design algorithms should take into account the limits of feedforward channels, especially in the case of rapidly time-varying waveforms.…”

Section: A Background and Motivationmentioning

confidence: 99%

“…As the optimization of the DFRC waveform p is performed at the transmitter side, this information must be conveyed to the receiver over a limited feedforward channel 4 for symbol decoding at the receiver. Following the models in [32], [34], we assume the existence of a low-rate feedforward channel (which is separate from the main communication channel) to send the control information regarding p to the receiver.…”

Section: B Communications Performance Metricmentioning

confidence: 99%

“…Algorithm 1 CCP-SOCP for Solving (29) Input: R τ , R ν , β ISL , w, λ τ Output: Radar-optimal waveform q Initialization: Compute the Vandermonde decompositions of Ξ τ and Ξ ν in (34). Choose an initial feasible point r 0 = q T 0 , (κ τ ν ) 0 T of (30).…”

Section: Ccp Based Iterative Algorithmmentioning

confidence: 99%

See 3 more Smart Citations

Limited Feedforward Waveform Design for OFDM Dual-Functional Radar-Communications

Keskin

Koivunen

Wymeersch

2021

IEEE Trans. Signal Process.

115

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We consider the problem of time-frequency waveform design for an OFDM dual-functional radar-communications (DFRC) system that communicates with an OFDM receiver while simultaneously estimating target parameters using the backscattered signals. In particular, the goal is to achieve a favorable performance trade-off between radar and communications by optimizing subcarrier powers in a time-frequency region of interest. First, we focus on radar-optimal waveform design to minimize the Cramér-Rao bound (CRB) on delay-Doppler estimation subject to an integrated side-lobe level (ISL) constraint in the delay-Doppler ambiguity domain, where a convex-concave procedure (CCP) is devised to solve the resulting non-convex fractional program. Next, we investigate the problem of DFRC trade-off waveform design to optimize the communications rate under radar similarity constraint. Unlike the traditional DFRC systems which ignore feedforward overhead for conveying transmit waveform control information, we assume the existence of a lowrate feedforward channel between the DFRC transceiver and the communications receiver. Relying on the covariance matrix of linear minimum mean-squared-error (LMMSE) estimates of input symbols, we derive a novel communications metric as a function of both subcarrier powers and forwarded control information, and propose a joint waveform and control signaling optimization (JWCSO) strategy that leverages the sparsity and rank-one structure of DFRC waveforms within an alternating maximization framework. Simulation results show that the proposed JWCSO approach provides significant performance gains over the conventional feedforward-agnostic waveforms and achieves nearoptimal radar-communications trade-off performance, reaching the boundary of the CRB-capacity region with only a limited feedforward information.

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Section: A Background and Motivationmentioning

confidence: 99%

Section: A Background and Motivationmentioning

confidence: 99%

Section: B Communications Performance Metricmentioning

confidence: 99%

Section: Ccp Based Iterative Algorithmmentioning

confidence: 99%

See 2 more Smart Citations

Limited Feedforward Waveform Design for OFDM Dual-Functional Radar-Communications

Keskin

Koivunen

Wymeersch

2021

IEEE Trans. Signal Process.

115

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“…In order to relax the dimensional constraint and include receive combining filters in the optimization of sum rate, an iterative block diagonalization scheme is proposed in [12]. Such iterative BD scheme requires the use of user-specific pilot symbols [15], [16] or feed-forwarding [17], [18] in order to coordinate the optimized precoders and receive combining filters to the users. The overhead of user-specific pilot symbols increases linearly with the number of users [19]; on the other hand, performance degradation due to quantization error is inevitable when using a feed-forward.…”

Section: Introductionmentioning

confidence: 99%

Partial Equivalent Channel Inversion Based Precoding with Mode Adaptation in Multiuser MIMO Systems

Godana

Ekman

Kansanen

2013

IEEE Trans. Wireless Commun.

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In downlink multi-user MIMO systems, Block Diagonalization (BD) is a well known linear precoding scheme that eliminates inter-user interference. However, BD requires precoded pilot symbols or feed-forwarding to coordinate precoder information from base station to users. Pre-coded pilot symbols, specially user specific pilots, have an overhead and complexity that grows with the number of users; on the other hand, feed-forward links are limited in capacity. In this paper, a new technique called Partial Equivalent Channel Inversion (PECI) based BD is proposed. PECI avoids the need for coordination of precoder information by combining BD with an inversion of a part of the equivalent channel. The performance of PECI based BD is evaluated analytically and demonstrated using various simulations. Even though PECI based BD is suboptimal, simulations show that the sum rate loss is very small and decreases with increase in spatial correlation. In order to improve the performance of PECI, a power allocation based mode selection algorithm, which requires forwarding only the number of streams allocated to a user, is also proposed. PECI is a general method that is also applicable to other precoding schemes in single and multi-cell precoding. Ethiopia, in 1985. He received the M.Sc. degree with Cum Laude in Electrical engineering (track: telecommunications) from Delft University of Technology, the Netherlands in Norway. His current research interests include signal processing in wireless communications, scheduling of radio resources, and dynamic modeling, and prediction of radio channels. He is participating in projects costal and arctic maritime operations and surveillance, sensor networks, cognitive radio, fixed broadband radio access and channel measurements. His involvement in the projects are mainly on RRM and channel modeling/prediction. Kimmo Kansanen received his M.Sc (EE) and Dr. Tech. degrees from University of Oulu, Finland in 1998 and 2005, respectively, where he was a research scientist and project manager at the Centre for Wireless Communications. Since Index Terms-Partial equivalent channel inversion, block diagonalization, mode selection, MIMO broadcast. Bruhtesfa E. Godana (S'09) was born in Wello,

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Performance Analysis and Joint Statistical Beamformer Design for Multi-User MIMO Systems

et al. 2020

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Noniterative Coordinated Beamforming for Multiuser MIMO Systems With Limited Feedforward

Cited by 6 publications

References 11 publications

Limited Feedforward Waveform Design for OFDM Dual-Functional Radar-Communications

Limited Feedforward Waveform Design for OFDM Dual-Functional Radar-Communications

Partial Equivalent Channel Inversion Based Precoding with Mode Adaptation in Multiuser MIMO Systems

Performance Analysis and Joint Statistical Beamformer Design for Multi-User MIMO Systems

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