Hybrid Analog-Digital Precoding for Interference Exploitation (Invited Paper)

Li, Ang; Masouros, Christos; Liu, Fan

doi:10.23919/eusipco.2018.8553509

Cited by 7 publications

(18 citation statements)

References 20 publications

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“…If we assume the analog precoder to be fixed when we design the precoding methods for the digital part, hybrid AD structures are equivalent to a fully-digital MIMO system transmitting through an effective analog channel. From this point of view, interference exploitation techniques can be readily applied to hybrid AD structures for additional performance improvements, as recently shown in [276]- [278]. In [276], the digital part of hybrid precoding employs CI precoding, and several analog precoding designs particularly tailored for CI-based hybrid precoding are presented and compared.…”

Section: Hybrid Analog-digital (Ad) Precodingmentioning

confidence: 99%

A Tutorial on Interference Exploitation via Symbol-Level Precoding: Overview, State-of-the-Art and Future Directions

Spano

Krivochiza

et al. 2020

IEEE Commun. Surv. Tutorials

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220

127

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Interference is traditionally viewed as a performance limiting factor in wireless communication systems, which is to be minimized or mitigated. Nevertheless, a recent line of work has shown that by manipulating the interfering signals such that they add up constructively at the receiver side, known interference can be made beneficial and further improve the system performance in a variety of wireless scenarios, achieved by symbol-level precoding (SLP). This paper aims to provide a tutorial on interference exploitation techniques from the perspective of precoding design in a multi-antenna wireless communication system, by beginning with the classification of constructive interference (CI) and destructive interference (DI). The definition for CI is presented and the corresponding mathematical characterization is formulated for popular modulation types, based on which optimization-based precoding techniques are discussed. In addition, the extension of CI precoding to other application scenarios as well as for hardware efficiency is also described. Proof-of-concept testbeds are demonstrated for the potential practical implementation of CI precoding, and finally a list of open problems and practical challenges are presented to inspire and motivate further research directions in this area.

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Section: Hybrid Analog-digital (Ad) Precodingmentioning

confidence: 99%

A Tutorial on Interference Exploitation via Symbol-Level Precoding: Overview, State-of-the-Art and Future Directions

Spano

Krivochiza

et al. 2020

IEEE Commun. Surv. Tutorials

Self Cite

220

127

View full text Add to dashboard Cite

show abstract

“…Aligning the angles of the phase-shifting network according to the first N l right singular vectors of H enables the system to achieve larger array gains. Note that similar aligning schemes based on the SVD decomposition of the channel are used in, e.g., [23], [32]. Although infinite-resolution phase shifters are required for an accurate implementation of this approach, in practice, the use of finite-resolution phase shifters is preferred due to practical constraints of variable phase shifters, particularly in systems with largescale antenna arrays as the number of phase shifters is proportional to the number of antenna elements.…”

Section: Hybrid Symbol-level Precoder Designmentioning

confidence: 99%

“…Having the upper bound given by (28) on the dominating order of L, the worst-case computational complexity of Algorithm 1 solving the design problem (14) with accelerated inner gradient steps can be obtained as shown in Table I. In practice, however, the outer optimization usually converges in a few cycles, as we will see in Section V. For comparison purposes, the complexities of hybrid symbol-level precoding techniques proposed in [23] and [24] is further reported in Table I. For the hybrid scheme in [23], the reported complexity order refers to the worst-case complexity of reaching an o -optimal solution to a linear problem via the interior-point method; see [47].…”

Section: Analysis Of Computational Complexitymentioning

confidence: 99%

“…Power-efficient transmitter architectures, including antenna selection and analog-only, are studied for symbol-level precoding in [25], where it has been shown that the analog-only design can outperform the other schemes especially when the transmit array size is much larger than the number of UEs. An even more cost-effective hybrid structure is considered in [23] where the baseband digitally precoded signal is subject to one-bit quantization due to the use of low-cost one-bit DACs for each RF chain. This excessive constraint, however, may limit the potential gain of symbol-level baseband signal processing.…”

Section: Introductionmentioning

confidence: 99%

“…Keeping in mind target data rates of multi-Gbps in mmWave systems, such a high phase-switching speed requirement might be prohibitive in two aspects: first, it significantly increases the power consumption in the analog circuitry, and second yet, more importantly, it might be challenging from an implementation point of view considering the current RF semiconductor technologies [26]. Among the aforementioned symbol-level precoding techniques, those proposed in [23] and [24] are more related to the scope of this work, and therefore will be considered in the paper for comparison purposes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Energy-Efficient Hybrid Symbol-Level Precoding for Large-Scale mmWave Multiuser MIMO Systems

Haqiqatnejad

Kayhan

Ottersten

2021

IEEE Trans. Commun.

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We address the symbol-level precoding design problem for the downlink of a multiuser millimeter wave (mmWave) multiple-input multiple-output (MIMO) wireless system where the transmitter is equipped with a large-scale antenna array. The high cost and power consumption associated with the massive use of radio frequency (RF) chains prohibit fully-digital implementation of the precoder, and therefore, we consider a hybrid analog-digital architecture where a smallsized baseband precoder is followed by two successive networks of analog on-off switches and variable phase shifters according to a fully-connected structure. We jointly optimize the digital baseband precoder and the states of the switching network on a symbol-level basis, i.e., by exploiting both the channel state information (CSI) and the instantaneous data symbols, whereas the phase-shifting network is designed only based on the CSI due to practical considerations. Our approach to this joint optimization is to minimize the Euclidean distance between the optimal fully-digital and the hybrid symbol-level precoders. Remarkably, the use of a switching network allows for powersavings in the analog precoder by switching some of the phase shifters off according to the instantaneously optimized states of the switches. Our numerical results indicate that, on average, up to 50 percent of the phase shifters can be switched off. We provide an analysis of energy efficiency by adopting appropriate power dissipation models for the analog precoder, where it is shown that the energy efficiency of precoding can substantially be improved thanks to the phase shifter selection approach, compared to the fully-digital and the state-of-the-art hybrid symbol-level schemes.

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Constructive Interference-Based Symbol-Level Precoding Design for Millimeter-Wave Massive Multiuser MIMO Systems With Hardware-Efficient Hybrid Precoding Architecture

Chen

2021

IEEE Access

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This study considers the constructive interference-based symbol-level precoding design problem in millimeter-wave massive multiuser multiple-input multiple-output systems with hybrid analogand-digital precoding architecture. In contrast to traditional hybrid precoding architecture in which the analog part is implemented by infinite-resolution phase shifters, analog precoders are achieved in this study using low-cost and energy-efficient switches and inverters. Our objective is to design a hybrid precoder that minimizes the Euclidean distance between the hybrid precoder and the optimal fully digital precoder. However, such a design problem is difficult due to the intricate coupling of digital and analog precoder variables. Thus, we apply the alternating minimization (AltMin) framework to decouple the considered problem into digital and analog precoder design problems and then solve for digital and analog precoders in an alternating manner. By adopting the AltMin framework, we obtain a closed-form solution for digital precoder. Nevertheless, solving the analog precoder design problem incurs combinatorial complexity, which we address by proposing a coordinate descent algorithm to sequentially update each element of the analog precoder with a closed-form expression. Simulation results reveal that the application of the proposed algorithm for the proposed hardware-efficient hybrid precoding architecture provides the desired balance among symbol error rate performance, power consumption, and hardware cost. INDEX TERMS Alternating minimization, finite resolution phase shifters, hybrid precoding, massive MIMO, millimeter-wave.

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Hybrid Analog-Digital Precoding for Interference Exploitation (Invited Paper)

Cited by 7 publications

References 20 publications

A Tutorial on Interference Exploitation via Symbol-Level Precoding: Overview, State-of-the-Art and Future Directions

A Tutorial on Interference Exploitation via Symbol-Level Precoding: Overview, State-of-the-Art and Future Directions

Energy-Efficient Hybrid Symbol-Level Precoding for Large-Scale mmWave Multiuser MIMO Systems

Constructive Interference-Based Symbol-Level Precoding Design for Millimeter-Wave Massive Multiuser MIMO Systems With Hardware-Efficient Hybrid Precoding Architecture

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