A PAPR reduction technique in OFDM transmissions using hierarchical QAM

Prabhu, Soubhagya S; Premalatha, P.

doi:10.1109/iccsp.2016.7754443

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…Results show that such procedure brings improvement on the considered issue. In [19], hierarchical modulation is utilized as a PAPR reduction method for OFDM. By increasing the distance between adjacent constellation points, PAPR can be reduced.…”

Section: Related Workmentioning

confidence: 99%

Superposition Coded-Orthogonal Frequency Division Multiplexing

Gökçeli¹,

Kurt²

2018

IEEE Access

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Orthogonal frequency division multiplexing (OFDM) technique is the most used approach in various wireless communication technologies due to its implementation advantages. However, OFDM has also some significant drawbacks, such as the sensitivity against real-time impairments and the poor peakto-average power ratio (PAPR) performance. These drawbacks decrease the usage potential of OFDM in future networks. Recent OFDM alternatives, which have been proposed in 5G waveform research activities, can provide limited improvements and these mostly include modified filtering operations when compared to the OFDM. In this paper, as a novel and flexible approach, superposition coding is adopted to OFDM, and superposition coded-OFDM (SC-OFDM) is proposed. By exploiting superposition coding as a new transmission dimension, an adaptive waveform solution that solves the PAPR problem without creating any inefficiency is provided. At the same time, throughput or error performance, and sensitivity against realtime impairments can also be improved. Features for each problem are proposed within the SC-OFDM approach. Performances of each SC-OFDM features are measured with extensive computer simulations and real-time experiments. Real-time experiments are realized by using software defined radio nodes and these are compared with the computer simulation results. To the best of authors' knowledge, such a comprehensive waveform design is proposed for the first time in the literature. As observed with the results, SC-OFDM can meet the requirements of future communication technologies.

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Section: Related Workmentioning

confidence: 99%

Superposition Coded-Orthogonal Frequency Division Multiplexing

Gökçeli¹,

Kurt²

2018

IEEE Access

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“…The poor power efficiency makes the reduction of PAPR more important in OFDM systems. In order to reduce this effect, various methods such as selected mapping, hierarchical QAM, wavelet transform, Karhunen-Loeve Transform, WHT, and double WHT have been proposed in [29][30][31][32][33][34]. Particularly, the studies using WHT in [33,34] have attracted attention because of their superior performance.…”

Section: General Framework Of Contributionsmentioning

confidence: 99%

Iterative Receiver with Low Complexity for Downlink Multicarrier Communications over Rapidly Time‐Varying Channels

Kabaoglu

Erdoğan

Aydin

2018

Wireless Communications and Mobile Computing

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This study proposes an iterative, joint channel estimation, equalization, and data detection method in the presence of high mobility for a multicarrier downlink system that communicates over rapidly time-varying channels. The proposed method uses a basis expansion method (BEM) which has low computational complexity and helps to reduce the number of coefficients needed to represent a time-varying channel and therefore is extremely easy to implement practically. Unlike the current literature, which is almost entirely focused on the uplink communication systems due to their computational costs, this method prioritizes the goal of being feasible in a downlink system with a reasonable performance. The proposed suboptimal algorithm is based on the space-alternating generalized expectation-maximization (SAGE) algorithm and the time-varying channel is represented by orthogonal basis functions obtained by means of discrete Walsh-Hadamard transform (DWHT). The resulting receiver iterates between maximum a posteriori (MAP) based channel estimation in the subspace spanned by the orthogonal basis functions and successive interference cancellation. Numerical examples show that the proposed algorithm has a satisfactory symbol error rate with low computational complexity and also has a reasonable peak-to-average power ratio (PAPR) reduction effect.

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A PAPR reduction technique in OFDM transmissions using hierarchical QAM

Cited by 2 publications

References 9 publications

Superposition Coded-Orthogonal Frequency Division Multiplexing

Superposition Coded-Orthogonal Frequency Division Multiplexing

Iterative Receiver with Low Complexity for Downlink Multicarrier Communications over Rapidly Time‐Varying Channels

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