FBMC OQAM: novel variant of OFDM

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shiv Om Tiwari ◽  
Rajeev Paulus

Abstract Orthogonal frequency division multiplexing (OFDM) revolutionizes the transmission technologies, including, optical as well as wireless communication. In OFDM the orthogonal nature of carriers makes it very good technique for data transfer. Still the out-of-band (OOB) radiation in OFDM leads to inter symbol interference (ISI) and bit error rate (BER) goes down. Moreover amplitude variations of the subcarriers lead to power variations and peak-to-average power ratio (PAPR) problem. To overcome these issues a novel filter bank multicarrier (FBMC) scheme is proposed, where each carrier is allowed to pass through to a separate filter and orthogonality among subcarriers is relaxed. Thus FBMC has better OOB and PAPR performance. In this work, we also have evaluated the PAPR performance by the simulation results. For the improvement of PAPR nonlinear companding scheme along with clipping is presented. The hybrid technique (clipping + companding) parameters are set in such a way that PAPR is reduced while signal power remains constant. Results are also compared with recent methods and it has been found that the proposed technique preforms better than other chosen techniques.

Author(s):  
Tahreer Mahmood ◽  
Seshadri Mohan

Multiple-input multiple-output technology together with orthogonal frequency division multiplexing (MIMO-OFDM) is an effective technique to combat multi-channel fading and to improve bandwidth efficiency. Simultaneously, it also increases the system's ability to provide reliable transmission. However, the main disadvantage of OFDM is the high peak-to-average-power ratio (PAPR), which, if not mitigated, will negatively impact practical applications. The high PAPR increases complexity and Bit Error Rate. In this research, the authors investigate the factors influencing the PAPR performance of both OFDM and MIMO-OFDM systems. The objective of this research is to make researchers in this field become familiar with this problem as well as to impart an understanding of the factors that influence PAPR. In this study, the authors classify the factors that impact PAPR into modulation schemes and a number of sub-carriers. These parameters influence the PAPR performance have been analyzed and simulated by using MATLAB. It is observed that the numbers of sub-carriers have a great effect on the PAPR performance. However, modulation schemes can have a small effect on PAPR performance.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Jurong Bai ◽  
Hang Dai ◽  
Feng Zhao ◽  
Yi Yang ◽  
Yanben Wang

AbstractIn this paper, a combination of Tone Reservation-Signal to Clipping noise Ratio (TR-SCR) and Companding schemes is proposed for underwater wireless optical communication (UOWC), in order to solve the problem of high peak-to-average power ratio (PAPR) of underwater Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) system. Two optical modulation schemes, namely Direct Current-biased Optical OFDM (DCO-OFDM) and Asymmetrically Clipped Optical OFDM (ACO-OFDM), are adopted separately to achieve intensity modulation/direct detection over the seawater channel, with a distance of 100 meters of wireless optical transition to obtain the system bit error rate (BER). In the TR-SCR scheme, only the maximum amplitude signal is selected to reduce the complexity of the algorithm. The LSA method is introduced in the TR-SCR scheme for iteratively updating the signal to speed up the convergence. Finally, with the combination of the Companding scheme, the PAPR performance is significantly improved. The PAPR of the underwater optical OFDM system is reduced to 3.85 dB with its BER still satisfying the UOWC system requirements.


2012 ◽  
Vol 235 ◽  
pp. 53-57
Author(s):  
Hua Wei Zhang ◽  
Nan Li

Compared with the single carrier systems, orthogonal frequency division multiplexing (OFDM) has many advantages of higher bandwidth efficiency and stronger anti-multi-path ability. However, OFDM technology also has some disadvantages, including the multi-carrier synchronization and higher peak-to-average power ratio. In order to solve the higher peak-to-average power ratio problem, this article combines the double-level optimal search method and Kwon suboptimal method, proposes a threshold-based double-level optimal search algorithm. The method is an improved PTS algorithm and is a linear process. The simulation proves that, with the same optimization grouping parameters and auxiliary information, the new algorithm with a reasonable threshold, which has a smaller loss of reducing PAPR performance, greatly reduces the system complexity.


2021 ◽  
Author(s):  
Hamis Hesham ◽  
Tawfik Ismail

Abstract The light fidelity (LiFi) has been successfully used to achieve high data transfer rates, high security, great availability, and low interference. In this paper, we propose a LiFi system consisting of a combination of non-orthogonal multi-access (NOMA), asymmetrically-clipped optical (ACO) and filter bank multicarrier (FBMC) techniques combined with offset quadrature amplitude modulation (OQAM). The paper also applies a $\mu$-law companding approach for a high peak to average power ratio (PAPR) reduction of the FBMC/OQAM scheme. The combination of NOMA, ACO-FBMC/OQAM, and $\mu$-law companding allows a significant increase in throughput and a significant reduction in non-served users. An appropriate algorithm is developed considering two scenarios, maximize the throughput and minimize the number of blocked (non-served) users. The results show that the throughput of the system can be increased by $1.8$ compared to FBMC and OFDM. Furthermore, the proposed system reduces the number of blocked users below $10\%$, while the system can provide $30\%$ or $60\%$ in case only the FBMC or OFDM is used, respectively.


Author(s):  
Abhishek Kumar

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation that divides the available spectrum into a finite number of carriers and applied into a digital transmission system. But it has some drawbacks such as sensitivity in inter-carrier interference, high peak to average power ratio and insufficient cyclic prefix in spectrum. These drawbacks may be reduced by a technique known as Generalized Frequency Division Multiplexing (GFDM). In the present scenario, it is a high speed multi-carrier multiplexing data transfer scheme for the cellular network. This paper deals with a comparison between OFDM and GFDM and focuses on various techniques in OFDM and GFDM.


Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 257
Author(s):  
Huandong Hong ◽  
Zhengquan Li

Conventional optical orthogonal frequency division multiplexing (OFDM) schemes, such as adaptively biased optical OFDM (ABO-OFDM) and hybrid asymmetrically clipped optical OFDM (HACO-OFDM), are unable to tap all the resources of the subcarriers and only achieve relatively high power efficiency. In this paper, a hybrid adaptive bias optical OFDM (HABO-OFDM) scheme for visible light communication (VLC) is proposed to improve spectral efficiency and power efficiency. In the proposed HABO-OFDM scheme, different optical OFDM components are combined for transmission at the same time, and the adaptive bias is designed to ensure the non-negativity, as well as obtaining significantly high power efficiency. Meanwhile, the implementation complexity of the HABO-OFDM receiver is notably lower than the conventional superimposed optical OFDM schemes. Simulation results show that the proposed HABO-OFDM scheme outperforms ABO-OFDM and HACO-OFDM in terms of both peak-to-average-power ratio (PAPR) and power efficiency. The PAPR performance of HABO-OFDM is about 3.2 dB lower than that of HACO-OFDM and 1.7 dB lower than that of ABO-OFDM. Moreover, we can see that the Eb(elec)/N0 required for HABO-OFDM to reach the BER target is lower than the other two schemes at the Bit rate/Normalized bandwidth range of 3.5 to 8.75, which means that the power efficiency of HABO-OFDM is higher in this range.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Deepak Kedia ◽  
Arti Modi

Single-carrier FDMA (SC-FDMA) is becoming more and more popular in multiuser communication because of its lower PAPR value. Apart from this, many other hybrid access techniques have also been explored in the literature for application to 4G wireless mobile communication. Still there is a need to explore newer techniques which could further reduce the PAPR value without any degradation in system BER. Keeping this in view, a modified hybrid technique SC-FDMA-DSCDMA has been proposed in this paper and it is found to provide significantly lower PAPR than SC-FDMA system with no degradation in BER performance. This paper extensively compares the BER and PAPR performance of various other multicarrier techniques for 4G wireless communications such as OFDMA, MC-DS-CDMA, and SC-FDMA with proposed SC-FDMA-DSCDMA scheme. Simulation results show that SC-FDMA-DSCDMA technique performs better than any other OFDM-CDMA based system for wireless communication.


Orthogonal frequency division multiplexing (OFDM) schemes are used extensively nowadays in large number of practical systems, but OFDM may not be the ideal solution for 5G scenarios because OFDM has high Out of band emission (OOBE) due to high spectral leakage and high peak to average power ratio (PAPR). Therefore Filtered OFDM (F-OFDM), which uses sub band filtering, is proposed as the most flexible waveform for 5G. However there is no work listed in the literature so far that compares the bit error rate (BER) performance of F-OFDM and conventional OFDM in AWGN, Rayleigh and Rician channel. This paper presents the simulation results on the BER performance of F-OFDM and OFDM in presence of AWGN, Rayleigh and Rician channel. The comparison is also done in terms of OOBE and PAPR factor. Results indicate that F-OFDM shows significantly less spectral leakage with same performance in terms of BER compared to conventional OFDM. However for the cases considered, OFDM performance is slightly better than F-OFDM in terms of PAPR factor.


2019 ◽  
Vol 8 (2) ◽  
pp. 4347-4353

Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO OFDM) is a key technology for contemporary communication systems due to its spectral efficiency, higher data rates, better diversity gain, good link reliability and both inter symbol interference (ISI) and multipath fading free transmission. However, due to the presence of OFDM, MIMO-OFDM suffers from high peak to average power ratio (PAPR). Even though, several schemes are available to mitigate PAPR, there is no standard solution. Selective Mapping (SLM) significantly reduces the PAPR in OFDM systems at the cost of computational complexity (CC). The CC of SLM can be reduced by proper design of SLM. This paper considers a low complexity SLM (LC SLM) scheme in which both the CC and length of the index of selected phase sequence are significantly reduced. The PAPR of an SLM-OFDM depends on the number of subcarriers in OFDM, the number of candidate blocks in SLM and selected phase sequence and this paper investigate various phase sequences and analyses their PAPR performance. Simulation results show the superior performance of Riemann sequence over the other phase sequences.


2021 ◽  
Vol 9 (10) ◽  
pp. 1104
Author(s):  
Imran A. Tasadduq ◽  
Mohsin Murad ◽  
Pablo Otero

We propose and evaluate the performance of a continuous phase modulation based orthogonal frequency division multiplexing (CPM-OFDM) transceiver for underwater acoustic communication (UAC). In the proposed technique, the mapper in traditional OFDM is replaced by CPM while a realistic model of underwater channel is employed. Bit error rate (BER) as well as peak to average power ratio (PAPR) performance of the proposed scheme is evaluated using Monte-Carlo simulations. The error performance observed clearly establishes the superiority of CPM-OFDM over traditional OFDM schemes. Specifically, a value of 7/16 or 9/16 for the modulation index gives the best error performance. Furthermore, the error performance of the proposed scheme is within acceptable values up to a transmitter–receiver distance of 1.5 km. Additionally, the PAPR performance of the proposed scheme suggests that like other OFDM schemes, a PAPR reduction scheme is mandatory for acceptable PAPR performance of CPM-OFDM.


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