# PAPR Reduction in MIMO-OFDM Based on Polar Codes and Companding Technique

12 Apr 2019-pp 1-6

TL;DR: This work proposes and study a new method based on μ-Law companding type and Polar Codes to reduce PAPR values in a MIMO-OFDM system that operates with less complexity and outperforms the most well-known methods.

Abstract: MIMO-OFDM is a method adopted by new highspeed communications technologies such as IEEE802.11, IEEE 802.16 and 4G. Among the advantages of MIMO-OFDM, its ability to increase the transmission rate, and its adaptation to multipath channel with fading. Unfortunately the signals modulated by the OFDM technique generate high values of Peak-to-Average Power Ratio (PAPR). To solve this major drawback, several techniques have been proposed in literature. Among others, we find those that combine coding and companding. In this context we propose and study a new method based on μ-Law companding type and Polar Codes to reduce PAPR values in a MIMO-OFDM system. In order to evaluate the performances of our method in terms of PAPR and BER, several simulations are performed taking into consideration parameters related to coding and companding rates, and the number of sub carriers. The plotted curves show that the results are very significant; indeed, firstly our method achieves a gain of 8 dB in terms of PAPR by ensuring a good compromise in term of BER thanks to the use of the Polar Codes. Secondly our method operates with less complexity and outperforms the most well-known methods.

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TL;DR: In this article , a modified Selective Mapping based PTS (SMPTS) method was proposed to enhance PAPR reduction and power amplifier efficiency in OFDM and MIMO (multiple inputs, multiple outputs)-OFDM methods through selective mapping based PTS method combined with power amplifier reduction methods.

##### References

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TL;DR: The paper proves that, given any B-DMC W with I(W) > 0 and any target rate R< I( W) there exists a sequence of polar codes {Cfrn;nges1} such that Cfrn has block-length N=2n, rate ges R, and probability of block error under successive cancellation decoding bounded as Pe(N,R) les O(N-1/4) independently of the code rate.

Abstract: A method is proposed, called channel polarization, to construct code sequences that achieve the symmetric capacity I(W) of any given binary-input discrete memoryless channel (B-DMC) W. The symmetric capacity is the highest rate achievable subject to using the input letters of the channel with equal probability. Channel polarization refers to the fact that it is possible to synthesize, out of N independent copies of a given B-DMC W, a second set of N binary-input channels {WN(i)1 les i les N} such that, as N becomes large, the fraction of indices i for which I(WN(i)) is near 1 approaches I(W) and the fraction for which I(WN(i)) is near 0 approaches 1-I(W). The polarized channels {WN(i)} are well-conditioned for channel coding: one need only send data at rate 1 through those with capacity near 1 and at rate 0 through the remaining. Codes constructed on the basis of this idea are called polar codes. The paper proves that, given any B-DMC W with I(W) > 0 and any target rate R< I(W) there exists a sequence of polar codes {Cfrn;nges1} such that Cfrn has block-length N=2n , rate ges R, and probability of block error under successive cancellation decoding bounded as Pe(N,R) les O(N-1/4) independently of the code rate. This performance is achievable by encoders and decoders with complexity O(N logN) for each.

3,554 citations

### "PAPR Reduction in MIMO-OFDM Based o..." refers methods in this paper

...• Hybrid techniques: is one of the most used techniques by combing other techniques like Genetic Algorithm with SLM, PTS or coding and companding [19-22]....

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TL;DR: Orthogonal frequency division multiplexing for MIMO channels (MIMO-OFDM) is considered for wideband transmission to mitigate intersymbol interference and enhance system capacity.

Abstract: Multiple transmit and receive antennas can be used to form multiple-input multiple-output (MIMO) channels to increase the capacity by a factor of the minimum number of transmit and receive antennas. In this paper, orthogonal frequency division multiplexing (OFDM) for MIMO channels (MIMO-OFDM) is considered for wideband transmission to mitigate intersymbol interference and enhance system capacity. The MIMO-OFDM system uses two independent space-time codes for two sets of two transmit antennas. At the receiver, the independent space-time codes are decoded using prewhitening, followed by minimum-Euclidean-distance decoding based on successive interference cancellation. Computer simulation shows that for four-input and four-output systems transmitting data at 4 Mb/s over a 1.25 MHz channel, the required signal-to-noise ratios (SNRs) for 10% and 1% word error rates (WER) are 10.5 dB and 13.8 dB, respectively, when each codeword contains 500 information bits and the channel's Doppler frequency is 40 Hz (corresponding normalized frequency: 0.9%). Increasing the number of the receive antennas improves the system performance. When the number or receive antennas is increased from four to eight, the required SNRs for 10% and 1% WER are reduced to 4 dB and 6 dB, respectively. Therefore, MIMO-OFDM is a promising technique for highly spectrally efficient wideband transmission.

546 citations

### "PAPR Reduction in MIMO-OFDM Based o..." refers methods in this paper

...Several standards, such as 4G, WiFi and WiMAX, combine MIMO and OFDM to improve system performance [1,2,3]....

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TL;DR: This paper gives encoding and decoding methods for systematic polar coding that preserve the low-complexity nature of non-systematic polar coding while guaranteeing the same frame error rate.

Abstract: Polar codes were originally introduced as a class of non-systematic linear block codes. This paper gives encoding and decoding methods for systematic polar coding that preserve the low-complexity nature of non-systematic polar coding while guaranteeing the same frame error rate. Simulation results are given to show that systematic polar coding offers significant advantages in terms of bit error rate performance.

322 citations

### "PAPR Reduction in MIMO-OFDM Based o..." refers background in this paper

...Polar Codes are a class of error correction codes discovered in 2009 by Erdal Arikan [23]....

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01 Jul 2017TL;DR: This paper accentuates on the suitability of polar codes for the 5G scenarios, and Polar code appropriateness for URLLC and mMTC scenarios is shown in simulation results.

Abstract: Channel Coding for the 5G wireless networks is facing novel challenges to endorse innumerable emerging use cases and applications with miscellaneous performance aspects. With respect to existing state of art codes; 5G channel Codes have diverse requirements of code lengths and rates, as well as throughput, latency and decoding complexity. Therefore, Turbo codes and LDPC codes that played key enablers in 3G and 4G systems are already unproven for many new 5G applications. Polar code is believed as prominent breakthrough in channel coding theory. It guarantees apical performance for 5G scenarios and hence it is considered as a promising candidate for the 5G New Radio. This paper accentuates on the suitability of polar codes for the 5G scenarios. Polar code appropriateness for URLLC and mMTC scenarios is shown in simulation results.

48 citations

### "PAPR Reduction in MIMO-OFDM Based o..." refers background in this paper

...These features therefore make the polar codes very attractive for research and industrial applications namely MIMO-OFDM [24,25] and 5G [26]....

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