Precoding feedback scheme based on Jacobi rotations to generate the feedback in the uplink. For a wireless communication system including a transmitter and a receiver. The system may use either a single codeword (SOW) or a double codeword (DCW). The precoding scheme is based on transmit beamforming (TxBF). Differential feedback is considered, with periodic non-differential feedback to avoid error accumulation or propagation due to differential processing. Precoding feedback scheme based on Jacobi rotations to generate the feedback in the uplink. For a wireless communication system including a transmitter and a receiver. The system may use either a single codeword (SOW) or a double codeword (DCW). The precoding scheme is based on transmit beamforming (TxBF). Differential feedback is considered, with periodic non-dif f erential feedback to avoid error accumulation or propagation due to differential processing.

Method and apparatus for providing efficient precoding feedback in a mimo wireless communication system

In this paper, an adaptive limited feedback linear precoding technique for temporally correlated multiple-input multiple-output (MIMO) channels is proposed, where the receiver has perfect channel knowledge but the transmitter only receives a quantized channel direction. To perform adaptation to the time correlation structure, we employ a differential feedback, where the "amount" of the perturbation added to the previous precoder is determined by the statistics of the directional variation. Based on random matrix quantization analysis, we develop a spherical cap codebook approach, where the cap is centered at the previous precoder and the radius of the cap is determined proportional to the identified directional variation. If the channel is highly correlated in time, it is shown that the proposed differential feedback scheme achieves significant throughput improvement in the large codebook size regime. The rest of the paper is devoted to developing a systematic spherical cap codebook generation method. The developed approach employs a feedback scheme that uses a differential rotation of the previously used precoder. Our codebook adaptation is based on generating a perturbation in Euclidean space and projecting the perturbation onto the unitary space. Simulation results show that the proposed adaptation scheme accurately tracks the channel using only a small rate of feedback.

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MIMO Systems with Limited Rate Differential Feedback in Slowly Varying Channels

A method and apparatus for uplink power control in multiple-input multiple-output (MIMO) includes setting a transmit power level for a physical uplink shared channel (PUSCH) transmission.

Method and apparatus for uplink power control in multiple-input multiple-output

A salient advantage of single carrier frequency division multiple access (SC-FDMA) is low peak-to-average power ratio (PAPR) which is lower than that of OFDMA. Precoding using transmit beamforming (TxBF) is a MIMO spatial multiplexing method that increases the data throughput significantly. However, when applied to SC-FDMA, it increases the PAPR. In this paper, we describe how we can apply TxBF to an SC-FDMA system and show its effect on PAPR We then consider the effects of precoder averaging across subcarriers and quantization, typically used to reduce feedback overhead, on the PAPR Comparisons are made with single antenna, non-precoded spatial multiplexing (SM) and space-frequency block coding (SFBC) systems. Lastly, we show that a modest amount of amplitude clipping can reduce PAPR to an acceptable level with virtually no harmful effects on performance or spectral growth.

Peak Power Characteristics of Single Carrier FDMA MIMO Precoding System

Power control for devices having multiple transmit antennas are disclosed, including power control methods for Physical Uplink Control Channel (PUCCH) and Sounding Reference Signal (SRS) transmissions for a wireless transmit/receive unit (WTRU). The PUCCH and SRS power control methods include selecting a multiple input multiple output (MIMO) mode and changing the power of the PUCCH or SRS transmission based on the selected MIMO mode. Another power control method estimates an antenna gain imbalance (AGI) for a WTRU having at least two transmit antennas. The AGI is based on measuring a Reference Signal Received Power (RSRP) on each transmit antenna. Each transmit antenna is then scaled by an AGI scaling factor based on the estimated AGI.

Power control for devices having multiple antennas

In this paper a multiple-input multiple-output (MIMO) scheme proposed for single carrier frequency division multiple access (SC-FDMA) system is described. Transmit and receive algorithms are developed for SC-FDMA MIMO systems. A spatial precoding closed-loop transmit beamforming (TxBF) algorithm for SC-FDMA MIMO system which uses singular value decomposition (SVD) at the transmitter and linear minimum mean square error (LMMSE) equalization at the receiver is described. Quantization and feedback schemes to support closed-loop operation are discussed. The PAPR effects and a mitigation approach are presented. Simulation results are shown for throughput vs. signal-to-noise ratio (SNR). The performance for this new TxBF algorithm is compared to Single-Input-Multiple Output (SIMO) performance. Also, single and dual-codeword performance is considered.

Uplink Single-User MIMO for 3GPP LTE

An efficient feedback design for single carrier frequency division multiple access (SC-FDMA) multiple input multiple output (MIMO) communication systems is described. We consider a codebook-based approach for MIMO pre-coding and quantization of feedback information. Differential processing is used to generate the updates iteratively for the feedback information between feedback instances. An approach of combined differential and non-differential feedback is considered for reduced feedback overhead and improved performance. A differential feedback with periodic error reset for differential processing is described. The performance of MIMO communication systems using pre-coding/transmit beamforming and the described feedback design is evaluated for SC-FDMA systems. The effects of pre-coding and feedback quantization, sub-carrier grouped feedback and feedback delay are investigated.

Efficient Feedback Design for MIMO SC-FDMA Systems

This paper presents computational complexity and memory counts for various data detection algorithms for TD-SCDMA. The algorithms include joint detection (JD) using Cholesky decomposition, successive interference cancellation based joint detection (SIC-JD), JD using fast Fourier transform (FFT-JD), single-user detection (SUD) and matched-filter based SIC (MF-SIC).

Jung-Lin Pan

Papers

Uplink Single-User MIMO for 3GPP LTE

Efficient Feedback Design for MIMO SC-FDMA Systems

Complexity and efficiency of data detection algorithms for TD-SCDMA