Covariance-based linear precoding

Zerlin, B.; Joham, Michael; Utschick, Wolfgang; Nossek, Josef A.

doi:10.1109/jsac.2005.858890

Cited by 18 publications

(5 citation statements)

References 21 publications

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“…Considering the case of β ⊥ τ → 0, (33) immediately gives t ⋆ → ∞. Applying this result into (29) gives:…”

Section: A Lower Bounds Of the Mf Beamforming Gainmentioning

confidence: 92%

“…where λ n (> 0) (n = 0, ..., N − 1) are the singular-values of H. For practical massive-MIMO systems, SVD is a highcomplexity algorithm, and the matched-filter (MF) is often employed as a low-complexity alternative (e.g., [29], [30]). Conventional throughput-oriented MF beamforming often superimposes multiple data-streams for better spectral efficiency.…”

Section: B Problem Statementmentioning

confidence: 99%

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Massive-MIMO MF Beamforming with or without Grouped STBC for Ultra-Reliable Single-Shot Transmission Using Aged CSIT

Wang,

Ma,

et al. 2021

Preprint

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The technology of using massive transmit-antennas to enable ultra-reliable single-shot transmission (URSST) is challenged by the transmitter-side channel knowledge (i.e., CSIT) imperfection. When the imperfectness mainly comes from the channel time-variation, the outage probability of the matchedfilter (MF) transmitter beamforming is investigated based on the first-order Markov model of the aged CSIT. With a fixed transmit-power, the transmitter-side uncertainty of the instantaneous signal-to-noise ratio (iSNR) is mathematically characterized. In order to guarantee the outage probability for every single shot, a transmit-power adaptation approach is proposed to satisfy a pessimistic iSNR requirement, which is predicted using the Chernoff lower bound of the beamforming gain. Our numerical results demonstrate a remarkable transmit-power efficiency when comparing with power control approaches using other lower bounds. In addition, a combinatorial approach of the MF beamforming and grouped space-time block code (G-STBC) is proposed to further mitigate the detrimental impact of the CSIT uncertainty. It is shown, through both theoretical analysis and computer simulations, that the combinatorial approach can further improve the transmit-power efficiency with a good tradeoff between the outage probability and the latency.

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“…Considering the case of β ⊥ τ → 0, (33) immediately gives t ⋆ → ∞. Applying this result into (29) gives:…”

Section: A Lower Bounds Of the Mf Beamforming Gainmentioning

confidence: 92%

Section: B Problem Statementmentioning

confidence: 99%

Massive-MIMO MF Beamforming with or without Grouped STBC for Ultra-Reliable Single-Shot Transmission Using Aged CSIT

Wang,

Ma,

et al. 2021

Preprint

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“…Therefore, much research effort has been directed at reducing the feedback CI. Some of the proposed approaches include quantization of the CI [14], representation of the CI using a codebook of finite codewords or derivation of precoders by utilizing partial CI [22] such as channel correlation [23], covariance [24], or mean [25].…”

Section: Precoding Matrix Selection Methodsmentioning

confidence: 99%

Design of reduced complexity feedback precoding for MIMO‐OFDM

Ghirmai

2014

Int J Communication

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Beamforming technique is applied to significantly increase the performance of a MIMO system, if the channel information (CI) of the communication system is available at the transmitter. For the transmitter to obtain the entire CI, however, a considerable reverse-link bandwidth is required. To save the bandwidth, a limited-rate closed-loop system, therefore, uses a predetermined codebook which is derived from the CI. The codebook consists of a finite number of precoders out of which the index of the best one is transmitted from the receiver to the transmitter using only a few bits saving substantial bandwidth. However, the amount of bits that need to be fed back can still be significantly large for MIMO-OFDM systems when the precoding matrix index (PMI) for each subcarrier should be transmitted. Such per-subcarrier precoding scheme has high feedback overhead and also incurs huge computational cost to determine the best PMI for each subcarrier. We, therefore, propose a per-band precoding scheme that precodes a band (group) of subcarriers by only one precoder. More importantly, we develop, for the proposed per-band scheme, reduced-complexity precoding selection methods that lead to the design of efficient receivers. The effectiveness of the proposed scheme is investigated through computer simulations. 143When a MIMO transmitter obtains a channel information (CI), the performance of the communication system can be further enhanced [4][5][6]. The availability of the CI enables the transmitter to precode the data and beamform the transmitted signal in such a way that the signal eigen modes match to those of the channel modes [7]. Applying precoding decomposes the signal into orthogonal spatial eigen modes and it effectively decouples the channel into parallel subchannels that transmit independent signals. Such decoupling of the channel provides the ability to adapt the allocation of power to the eigen modes of the signal according to the strength of their corresponding channel modes [8,9]. Therefore, it is well known that precoding, or beamforming, along with an optimal power allocation scheme, water-filling, enables a MIMO system to achieve maximum capacity [10,11].In cellular time-division-duplex systems, the transmitter may be able to derive the forward CI, using the principle of reciprocity, from the estimates of the reverse channel. In cellular frequencydivision duplex systems, however, because reciprocity does not apply, the forward CI cannot be derived from the estimates of the reverse channel. An alternative approach would be to send back CI from receiver to transmitter over an additional reverse channel [12]. Feeding back the entire CI to the transmitter, however, would require a high-rate reverse channel which demands considerable additional transmission resource. Reducing the amount of feedback overhead has been a subject of a lot of research work, and, therefore, several methods have been proposed in the literature [13,14].A limited-feedback closed-loop MIMO system employs a codebook to represent the CI tha...

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“…Iin FDD-UMTS (WCDMA) [1] the receivers' channel estimates ("phase references") are typically based on a common pilot sequence, which is designated for all receivers (see [2] and [3] for details). There is a 'primary common pilot" transmitted to all users in the sector and "secondary common pilots" transmitted over a fixed grid-of-beams to exploit the antenna gain.…”

Section: Introductionmentioning

confidence: 99%

“…A first approach to this problem was given by [3] based on sum MSE, where the matched filter (Rake receiver) at the receiver and its incomplete CSI from the common pilot channel was modeled explicitly. Another adaptive precoding is mentioned in [2] but not explained in detail, which shows significant gains in cell capacity over a fixed-beam approach and an adaptive precoding using the dedicated pilot sequence.…”

Section: Introductionmentioning

confidence: 99%

Min-Max MSE Precoding for Broadcast Channels Based on Statistical Channel State Information

Assir¹,

Dietrich²,

Joham

et al. 2006

2006 IEEE 7th Workshop on Signal Processing Advances in Wireless Communications

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Linear precoding for the wireless MIIMO broadcast channel with multiple antennas at the transmitter and non cooperative single antenna receivers is considered. For statistical channel state information (CSI) at the transmitter a novel opti mization problem for adaptive precoding based on the mean square error (MSE) is solved, which can also deal with incomplete CSI at the receivers, i.e., the receivers' channel estimates rely on a common pilot channel. We explicitly model the receivers' (limited) processing capabilities, which leads to a performance advantage over existing signal-tointerference-and-noise-ratio (SINR) approaches.

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Covariance-based linear precoding

Cited by 18 publications

References 21 publications

Massive-MIMO MF Beamforming with or without Grouped STBC for Ultra-Reliable Single-Shot Transmission Using Aged CSIT

Massive-MIMO MF Beamforming with or without Grouped STBC for Ultra-Reliable Single-Shot Transmission Using Aged CSIT

Design of reduced complexity feedback precoding for MIMO‐OFDM

Min-Max MSE Precoding for Broadcast Channels Based on Statistical Channel State Information

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