Iterative receivers with channel estimation for multi-user MIMO-OFDM: complexity and performance (original) (raw)
Related papers
Reduced complexity signal detection and channel estimation for iterative MIMO-OFDM systems
2016
Multi-Input Multi-Output (MIMO) is a key technology in broadband wireless communications, and it has been used in WiMax, LTE and WiFi (802.11n/ac). As Orthogonal Frequency Division Multiplexing (OFDM) can transform a frequency selective fading channel into a set of parallel frequency flat fading channels and thus greatly reduce the complexity of equalization, MIMO is typically combined with OFDM in practical applications. For a MIMO-OFDM system, the channel estimation and signal detection algorithms based on linear-minimum-mean-square-error (LMMSE) are often employed because of their good performance. But conventional algorithms typically require a matrix inversion with cubic level complexity, which is a major obstacle for practical implementation. To reduce the complexity, in this thesis, we focused on algorithms design by reducing the number of costly operations and the cost of each operation. Due to the law of large numbers, the matrix to be inverted, in both the LMMSE channel es...
Joint Twofold-Iterative Channel Estimation and Multiuser Detection for MIMO-OFDM Systems
IEEE Transactions on Wireless Communications, 2000
This paper presents an iterative receiver for Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems over time-variant wireless channels. The receiver performs joint decoding, channel estimation, and multiuser detection, with soft information iteratively provided by the single-user decoders. Time-variance is effectively taken into account exploiting the properties of the Discrete Prolate Spheroidal (DPS) sequences, being the bandlimited sequences with maximum energy concentration in time. Turbo codes are used for each transmit antenna, thus the receiver presents an iterative structure also in the single-user case. Simulation results for the performance are presented in terms of Bit Error Rate (BER) and Normalized Mean Square Error (NMSE) vs Signalto-Noise Ratio (SNR). The effects of the number of external and internal iterations as well as the number of pilots on the performance of the system are investigated.
Iterative Joint Channel Estimation and Symbol Detection for Multi-User MIMO OFDM
2006 IEEE 63rd Vehicular Technology Conference, 2006
Multiple-Input-Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems have recently attracted substantial research interest. However, compared to Single-Input-Single-Output (SISO) systems, channel estimation in the MIMO scenario becomes more challenging, owing to the increased number of independent transmitter-receiver links to be estimated. In the context of the Bell LAyered Space-Time architecture (BLAST) or Space Division Multiple Access (SDMA) multiuser MIMO OFDM literature, no channel estimation technique allows the number of users to be higher than the number of receiver antennas, which is often referred to as an "overloaded" scenario. In this contribution we propose a new Genetic Algorithm (GA) assisted iterative joint channel estimation and multiuser detection approach for MIMO SDMA-OFDM systems, which exhibits a robust performance in the above-mentioned overloaded scenario. Furthermore, GA-aided MultiUser Detection (MUD) techniques found in the literature can only provide a hard-decision output, while the proposed GA is capable of providing "soft" outputs, hence achieving an improved performance with the aid of channel decoders. Finally, a range of simulation results are provided to demonstrate the superiority of the proposed scheme.
Channel estimation for multiuser MIMO-OFDM systems based on Kalman algorithms
IOSR Journal of Electronics and Communication Engineering, 2014
The use of multiple antenna's at both transmitter and receiver to form multiple input and multiple output(MIMO) channels currently hold the potential to drastically improve the spectrum efficiency and capacity of future wireless communication system. For broadband systems ,OFDM turns a frequency selective channel into a set of parallel flat channels which reduces the receiver complexity. Designing a wireless receiver is a complicated task, thereby analysis is restricted on three functions of the receiver; Channel estimation, multiuser detectors and data decoding. By using iterative receiver algorithms different combinations of multiuser detectors and channel estimators are compared .The complexity-performance tradeoff and convergence behavior of the iterative receivers with channel estimation for multi user MIMO-OFDM system is analyzed.
IEEE Communications Letters, 2000
In this letter we compare the throughput performance of multiuser MIMO-OFDM systems operating in timevariant scenarios. The system employes packet-based transmissions and the receiver is twofold-iterative implementing multiuser detection, channel estimation and soft single-user decoding. Different combinations in terms of multiple-access techniques (time division, frequency division, and space division) and modulation schemes (BPSK and QPSK) are compared. Large-size constellations with interfering users in space-division multiple access (SDMA) are preferable in high-SNR range.
On the performance of iterative receivers for interfering MIMO-OFDM systems in measured channels
… 2008 42nd Asilomar …, 2008
This paper investigates the gains harvested through base station cooperation in the up-link for a multi-user (MU) Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system, operating in a real indoor environment. The base stations perform joint detection using an iterative receiver that carries out multi-user detection and channel estimation via soft information from the single-user decoders. Performance evaluation is carried out using real channels from an indoor dynamic dual ...
Joint Iterative Time-Variant Channel Estimation and Multi-User Detection for MIMO-OFDM Systems
IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference, 2007
This paper presents an iterative receiver for Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems. The receiver performs channel estimation and multi-user detection, with soft information iteratively provided by the single-user decoders. Timevariance is effectively taken into account exploiting the properties of the discrete prolate spheroidal (DPS) sequences. Simulation results for the performance are presented in terms of Bit Error Rate (BER) vs Signal-to-Noise Ratio (SNR), showing how the Single-User Bound (SUB) is approached in a few iterations.
Low-complexity iterative detection for overloaded uplink multiuser MIMO OFDM system
2012 International ITG Workshop on Smart Antennas (WSA), 2012
In this paper, an iterative interference cancellation multiuser detection (MUD) method is proposed for overloaded multiple-input multiple-output (MIMO) coded orthogonal frequency division multiplexing (OFDM) systems. In the first iteration, the low complexity RAKE reception is employed, and a successive interference cancellation (SIC)-based approach is used to choose the stronger user. In each iteration, the soft output of the convolutional decoder is fed back to improve the performance of the parallel interference cancellation (PIC). The simulation results show that, this technique can achieve near-optimum bit error rate (BER) performance at low SNR, with lower complexity than optimum maximum likelihood (ML) methods.
Comparison of Three List Detectors in Iterative Decoding and Channel Estimation in MIMO OFDM
Spread Spectrum Techniques and Applications, 2008
In this paper, the complexity and the performance of the list parallel interference cancellation (PIC) detection algorithm is compared to the ones of the K-best list sphere detector (LSD) and the increasing radius (IR)-LSD in a multipleinput multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system. The detectors are used as a soft MIMO detector to approximate the a posteriori probability (APP) algorithm in an iterative receiver to jointly decode the transmitted bits and to estimate the channel state. According to the results, the list PIC algorithm with a proper initialization gives some performance gain over the K-best LSD and loses only slightly to the IR-LSD. The IR-LSD is found to be the least complex of the algorithms when the number of visited nodes is measured.
Performance and Complexity Evaluation of Iterative Receiver for Coded MIMO-OFDM Systems
Mobile Information Systems, 2016
Multiple-input multiple-output (MIMO) technology in combination with channel coding technique is a promising solution for reliable high data rate transmission in future wireless communication systems. However, these technologies pose significant challenges for the design of an iterative receiver. In this paper, an efficient receiver combining soft-input soft-output (SISO) detection based on low-complexity K-Best (LC-K-Best) decoder with various forward error correction codes, namely, LTE turbo decoder and LDPC decoder, is investigated. We first investigate the convergence behaviors of the iterative MIMO receivers to determine the required inner and outer iterations. Consequently, the performance of LC-K-Best based receiver is evaluated in various LTE channel environments and compared with other MIMO detection schemes. Moreover, the computational complexity of the iterative receiver with different channel coding techniques is evaluated and compared with different modulation orders an...