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In this paper, a novel setpoint-based design approach for Irregular Repeat Accumulate (IRA) codes in iterative detection and decoding structures is presented. In contrast to conventional IRA code design in which the convolutional decoder is combined with the detector, the goal behind this approach is to keep the IRA decoding structure consisting of convolutional decoder and repetition decoder intact,...
Recently, a turbo-coded noncoherent space-time modulation scheme, which is aimed at providing both a high data transmission rate and a low receiving complexity, was proposed for noncoherent block fading channels. However, in cases where a large number of transmit antennas exist, the turbo code does not match well with the noncoherent space-time modulation scheme, and results in performance degradation...
We investigate successive interference cancellation (SIC) detectors that can achieve a close to optimum BER performance in spatial multiplexed multi-input multi-output (SM-MIMO) systems. We propose a low-complexity interference suppression strategy, in which an enhanced SIC is devised by introducing the feedback diversity to combat the error propagation in decision feedback loops. In order to constrain...
This paper presents a prototype of a high-throughput 4 × 4 64-QAM MIMO receiver consisting of a channel matrix QR decomposition, a soft-output K-Best MIMO detector and a Convolutional Turbo Code decoder. The proposed MIMO receiver provides low processing latency and a pipelined architecture scalable to a larger number of antennas and constellation order. Therefore, it is suitable for LTE-Advanced...
A novel concatenated multi-input multi-output (MIMO) communication system based on time varying linear transformation (TVLT) and Tanner codes is proposed in this paper. The girth 4 property of Tanner codes is discussed briefly. Combined with the outstanding distance property of Tanner codes, TVLT can provide full diversity and maximum coding gain at the same time without exhaustive search for the...
We consider turbo-coded MIMO systems with Rayleigh fading, when channel state information is available at the receiver only. Using our recently proposed linearly complex MIMO signal detector, we derive two bit-error-rate bounds on performance for such systems by extending the union bound method from turbo codes on the AWGN channel to time-varying MIMO fading channels. These bounds allow a designer...
LTE advanced standardization discusses OFDMA uplink transmission, which allows for different receiver algorithms than the DFT-spread OFDMA uplink in LTE. We present a hybrid MMSE/QRD-M turbo receiver concept for 4times4 MIMO-OFDMA uplink in LTE Advanced, running the complete baseband and decoding functionality on a Cell BE processor. Multi-user MIMO with different modulation levels on the same resources...
In this paper we introduce an improved version of the turbo layered orthogonal lattice detector (T-LORD), recently presented. This implementation, namely K-Best T-LORD, misses the performance of the turbo MAP detector by only few tenths of dB in various configurations, like the fully enhanced T-LORD. However, its complexity is quadratic in the number of transmitting antennas instead of exponential...
A threshold based list detector is presented for multiple-input multiple-output (MIMO) system. The detector is based on subset-sum algorithm. The algorithm make use of a low complexity sub optimal minimum mean square error (MMSE) detector to find the bit reliabilities, and uses these reliabilities to generate list of possible candidate data vectors. It is shown through analysis that this detector...
MIMO systems (with multiple transmit and receive antennas) are becoming increasingly popular, and many next-generation systems such as WiMAX, 3-GPP LTE and IEEE802.11n wireless LANs relay on the increased throughput of MIMO systems with up to four antennas at receiver and transmitter. High throughput implementation of the detection unit for MIMO systems is a significant challenge especially for higher...
In this paper, we will present a near-ML (maximum likelihood) MIMO (multiple input multiple output) detector explicitly optimized for parallel programmable baseband architectures, such as DSPs (digital signal processors) with VLIW (very long instruction word), SIMD (single instruction multiple data) or vector processing features. First, we propose the SSFE (selective spanning with fast enumeration)...
An a posteriori probability (APP) detector for multiple antenna channels has presented in . It has the high advantage of providing good performance but has an NP complexity, we studied near capacity and near outage performance over multiple antenna channels thanks to optimized bit interleaved coded modulations (BICM) . We will now present a sub-optimal soft-input soft-ouput (SISO) detector based on...
This paper presents a reduced-complexity soft-input soft-output detection scheme for low-density parity-check (LDPC) coded multiple-input multiple-output (MIMO) wireless communication systems employing turbo processing at the receiver. The detection algorithm is decomposed into the preprocessing and tree search stages. In preprocessing stage, we give an unbiased minimum mean-square error (MMSE) filtering...
In this paper, we propose a low complexity MIMO detection method for double space-time block (D-STBC) coded OFDM system. The proposed MIMO detector involves two step decoding process to efficiently de-correlate spatially-multiplexed / space-time-coded signals. The proposed MIMO detector collects feedback information from interfering spatial domain. Then, interference cancellation is applied once to...
Recently, we reported a low-complexity likelihood ascent search (LAS) detection algorithm for large MIMO systems with several tens of antennas that can achieve high spectral efficiencies of the order of tens to hundreds of bps/Hz. Through simulations, we showed that this algorithm achieves increasingly near SISO AWGN performance for increasing number of antennas in i.i.d. Rayleigh fading. However,...
This paper presents a modified turbo principle (MTP) for iterative detection and decoding in multiple-antenna systems whose detector uses the max-log-MAP algorithm. The modified turbo principle intensionally introduces dependency between the messages of the max-log-MAP detector and the decoder. Our simulation results show that the proposed MTP significantly reduces the performance loss due to the...
We analyze MIMO systems where either Bit-Interleaved Coded Modulation (BICM) by itself or in concatenation with Space-Time Block Codes (STBCs) is used at transmission, assuming iterative Turbo-like decoding at reception. We employ Serially-Concatenated Low-Density Generator Matrix (SCLDGM) codes specifically optimized for each system configuration, and focus on two relevant STBCs: the Golden code,...
In this paper, a novel approach using frame-based iterative channel fading parameters estimation technique from the received data sequence exploiting orthogonal property of the space-time block (STB) code is proposed. For practical implementation of STB code, the receiver requires to estimate these parameters. Regarding this type of estimation, the inherent orthogonal nature of STB code can be exploited...
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