Iterative Soft Compensation for OFDM Systems with Clipping and Superposition Coded Modulation

Tong, Jun; Ping, Li; Zhang, Zhonghao; Bhargava, V.K.

doi:10.1109/tcomm.2010.083110.09296

Cited by 28 publications

(14 citation statements)

References 38 publications

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“…Several techniques are available for reducing PAPR among them which are commonly used for the practical is given in [3]- [6]. Inter carrier interference (ICI) is overcome by orthogonal signals, placing the modulated carriers closely increases the spectral efficiency of the OFDM system [6].…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Clipping for PAPR Reduction in OFDM

Nagalikar¹,

Khot²

2017

IJERA

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A new Technique "Adaptive Clipping" is introduced to reduce the Peak to Average Power Ratio (PAPR) of OFDM system efficiently for wireless applications. In this technique, the threshold for clipping the signal is decided according to the peak size and number of peaks in the OFDM burst signal. A comparison is done between selective clipping and adaptive clipping and the results are shown in terms of Bit error rate (BER) and PAPR. Adaptive clipping offers nearly half a dB reduction in PAPR compared to selective clipping. With proposed adaptive clipping, PAPR of 3 dB is obtained with BER of 10 -4 . For a particular set of signals where there are large number of peak variations, adaptive clipping is more efficient in terms of BER compared to selective clipping. The simulation of adaptive clipping is done with the MATLAB software and the BER is plotted. An IEEE 806.11 standard is used for OFDM signal Transmission.

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Section: Introductionmentioning

confidence: 99%

“…Inter carrier interference (ICI) is overcome by orthogonal signals, placing the modulated carriers closely increases the spectral efficiency of the OFDM system [6].…”

Section: Introductionmentioning

confidence: 99%

Adaptive Clipping for PAPR Reduction in OFDM

Nagalikar¹,

Khot²

2017

IJERA

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“…Furthermore, a low-cost chip-bychip iterative detection algorithm can be adopted in SCM, where the complexity is independent of the number of layers [3,4]. Furthermore, SCM can be combined with orthogonal frequency division multiplexing (OFDM) to combat the frequency selective fading and improve the throughput [5].…”

Section: Introductionmentioning

confidence: 99%

Channel Estimation for SCM-OFDM Systems by Modified Kalman Filter

Peng¹,

Xiao²,

Li³

et al. 2013

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In this paper, the problem of channel estimation for superposition coded modulation-orthogonal frequency division multiplexing (SCM-OFDM) systems over frequency selective channels is investigated. Assuming that the path delays are known, a new channel estimator based on modified Kalman filter algorithms is introduced for the estimation of the multipath Rayleigh channel complex gains (CG). In the simulation, the mean square error (MSE) and bit-error-rate (BER) performances are given to verify the effectiveness of the Kalman estimation algorithms for SCM-OFDM systems.

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“…In [9],clipping is adopted in OFDM-IDMA systems for PAPR reduction but interference from clipping noise will reduce BER performance.…”

Section: Introductionmentioning

confidence: 99%

BER and PAPR Analysis of DFT Precoded OFDM Multilayer IDMA (P-OFDM ML IDMA) Signals

Aboul-Dahab¹,

Hagras²,

Elhaseeb³

2013

IJCCE

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Abstract-In this paper, Discrete Fourier Transform Precoded Orthogonal Frequency Division MultiplexingMultilayer Interleave Division Multiple Access (DFT P OFDM ML IDMA) communication system has been proposed. Chip by Chip (CBC) iterative receiver is used to recover the data in each layer. Also, different precoding techniques has been applied with and without clipping in the proposed P OFDM ML IDMA. Simulation results confirm that the DFT precoder provides better PAPR reduction compared with other precoded methods with and without clipping. BER and PAPR simulation results shows that the proposed DFT P OFDM ML IDMA brings about 7 dB PAPR reduction and 0.5 dB BER improvement compred with OFDM ML IDMA. The Simulations for the proposed DFT P OFDM ML IDMA with 2 -6 layers shows that the variation is 3.4 to 8.2 dB for the PAPR and 7.8 to 8.7 dB for the BER. So, the adaptive modulation can be simply realized by the proposed DFT P OFDM ML IDMA.Index Terms-PAPR, DFT, precoding, OFDM and IDMA. I. INTRODUCTIONInterleave-Division Multiple-Access (IDMA) was recently investigated. IDMA uses different chiplevel interleavers to distinguish different users, all adopting the same spreading sequence. The key principle of IDMA systems is that the chip-level interleavers should be different for different users. In addition, a low-cost CBC iterative detection can be utilized in the IDMA systems [1], [2]. Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission scheme that has become the technology choice for next generation wireless and wire line digital communication systems [3].IDMA can be combined with OFDM (OFDM-IDMA) integrates the advantages of both OFDM and IDMA in order to mitigate the intersymbol interference (ISI) and suppress the multiple access interference (MAI) simultaneously [4], [5]. OFDM-IDMA suffers PAPR problem. The transmitted signal of OFDM-IDMA has high PAPR, which may degrade the efficiency of power amplifier of the transmitters.A number of PAPR reduction schemes have been proposed for OFDM systems, such as clipping [6], partial transmit sequence method (PTS) [7], and selected mapping method (SLM) [8]. In [9],clipping is adopted in OFDM-IDMA systems for PAPR reduction but interference from clipping noise will reduce BER performance.To alleviate the above problem, precoding based techniques, however, show great promise as they are simple linear techniques to implement without the need of any side information. Precoding improves PAPR without increasing much complexity and without destroying the orthogonality between subcarriers. The precoding also improves the BER in comparison to normal OFDM system because of diversity gain obtained due to the spreading of data symbol among more than one subcarrier.In this paper, we present DFT precoder for clipped and Unclipped OFDM ML IDMA signals to reduce PAPR. Performance comparison is made with other transformbased precoders, namely Discrete Hartley Transform (DHT) and Zadoff-Chu Transform (ZCT) [7], [10].This paper is organized as follows: Section ...

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Iterative Soft Compensation for OFDM Systems with Clipping and Superposition Coded Modulation

Cited by 28 publications

References 38 publications

Adaptive Clipping for PAPR Reduction in OFDM

Adaptive Clipping for PAPR Reduction in OFDM

Channel Estimation for SCM-OFDM Systems by Modified Kalman Filter

BER and PAPR Analysis of DFT Precoded OFDM Multilayer IDMA (P-OFDM ML IDMA) Signals

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