Performance Comparison of OFDMA and SCFDMA in LTE Systems (original) (raw)

A COMPARATIVE ANALYSIS OF PAPR OF SC-FDMA AND OFDMA FOR LTE SYSTEMS

Long Term Evolution is a new advancement in the era of cellular technology emerged in recent decade that can accommodate the features of quite efficient radio access with high peak data rates as well as high capacity for voice links. Actually it is a journey toward 4 th generation with the recent 2G and 3G network operators. This revolution is an improvement over GSM, EDGE G, WCDMA/UMTS, and HSPDA and then HSPA+ to fulfil the demand of high speed mobile networks. This paper primarily describes a comparison of Single Carrier Frequency Division Multiple Access (SC-FDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) multiple access techniques.This comparison is carried out for the selection of multiple access schemes for the implementation of Long Term Evolution (LTE) systems. Also the advantages and disadvantages of SC-FDMA and OFDMA schemes are described. SC-FDMA is proved better than OFDMA in terms of Peak to average power ratio (PAPR).SCFDMA and OFDMA systems are modelled with MATLAB for PAPR analysis.

Optimal Performance of OFDM Signal using PAPR Reduction Techniques in LTE Systems

3rd Generation partnership project Long term Evolution (LTE) has been designed to provide more efficient use of radio networks. The LTE provides scalable bandwidth, latency reduction and higher data rates with improved mobility .Single carrier Frequency Division Multiple Access (SC-FDMA) has been selected for use in the Long Term Evolution (LTE) uplink due to its Peak-to-Average Power Ratio (PAPR) relative to OFDMA. The SC-FDMA scheme normally applies 16-Quadrature Amplitude Modulation (16-QAM),but amplitude phase shift keying(APSK) modulation has a lower PAPR than the 16-QAM,resulting in improved BER. This paper presents the DFT Spreading and Pulse shaping gives better performance with compare to selected mapping (SLM), Partial Transmit sequence (PTS), the 16-APSK modulation scheme and its effects on BER through its effects on the PAPR. Keywords – 16-APSK, 16-QAM, SC-FDMA, LTE, SLM, PTS, DFT and PAPR.

SC-FDMA & OFDMA in LTE Physical Layer

International Journal of Engineering Trends and Technology, 2014

This paper provides the introduction of LTE and the key components of its physical layer. These descriptions are simplified version of the detailed descriptions provided by 3gpp. In LTE, the OFDMA is used as downlink and SCFDMA as uplink modulation schemes; with OFDM as the basic building block. OFDMA is used for achieving high spectral efficiency in communication system; whereas, SC-FDMA for uplink multiple access scheme in LTE system. This paper evaluates the performance of SC-FDMA and OFDMA of LTE physical layer by considering different modulation schemes (BPSK, QPSK, 16QAM and 64QAM) on the basis of PAPR, BER and error probability. From the simulated results, it is observed that for a particular value of SNR, the BER increases for high order modulation (16-QAM and 64-QAM) in both OFDMA and SC-FDMA. However, the lower order modulation schemes (BPSK and QPSK) experience less BER at receiver; thus lower order modulations improve the system performance in terms of BER and SNR. In terms of bandwidth efficiency, the higher order modulation accommodates more data within a given bandwidth and is more bandwidth efficient as compared to lower order modulation. Thus, there exists a tradeoff between BER and bandwidth efficiency among these modulation schemes used in LTE. It is also observed that the error probability increases as order of modulation scheme increases. Therefore, the selection of modulation schemes in adaptive modulation is quite crucial based on these results.

LTE Quality of Service Enhancement Under OFDM Modulation Techniques

Wireless Personal Communications, 2020

Recently, to satisfy the ever-growing data needs, Long Term Evolution (LTE) has been deployed by many operators. LTE enables better spectrum management and avoids the adjacent channel interference by using the Orthogonal Frequency Division Multiple Access (OFDMA) for downlink and Single Carrier Frequency Division Multiple Access (SC-FDMA) for uplink connection. Even though the spectrum is limited, the number of active devices is increasing which requires the need for extra spectrum. OFDM is capable of better Quality of Service (QoS) as it avoids the multipath fading using equalization and immune to inter-symbol interference, in addition to its attractive spectral efficiency. However, the LTE system is suffered from Peak to Average Power Ratio (PAPR) which reduces the QoS of the communication. Therefore, in this paper, we have proposed a QoS enhancement using a hybridized clipping-selective mapping (Clip-SLM) technique. Different QoS enhancement methods are evaluated for different modulation techniques, phase sequences, and number of sub-carriers. From the simulation results, we have shown that the proposed hybridized technique results in significant PAPR reduction which results in substantial Bit Error Rate (BER) reduction and hence QoS enhancement.

Performance evaluation of PAPR in OFDM for UMTS-LTE system

2012 IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC), 2012

Next generation mobile telecommunication networks will provide high data rates needed for multimedia rich applications as the demand in mobile broadband services is expected to increase in the coming years. Orthogonal Frequency Division Multiplexing (OFDM) technique has been increasing its popularity as a transmission scheme for several radio technologies. One of the challenging issues in OFDM technique is its high peak-to-average power ratio (PAPR). This paper studies the performance of PAPR in long term evolution (LTE) of universal mobile telecommunications system (UMTS). The implementation will be based on specifications and protocols from 3rd Generation Partnership Project (3GPP) work groups. The simulator used to simulate UMTS-LTE environment has been developed in Matlab which follows the standard according to UMTS-LTE physical layer transmission scheme. Evaluation results show that reduction of PAPR can be seen in UMTS-LTE model compared to conventional OFDM model.

Performance Assessment of PAPR in OFDM System using Single Carrier - FDMA

International Journal of Computer Applications, 2014

Orthogonal frequency division multiplexing (OFDM) is a promising multicarrier modulation technique for high data rate communication. Unless, OFDM faces the peak-toaverage-power ratio (PAPR) problem that is a major drawback of multicarrier transmission system which leads to power inefficiency of high power amplifier (HPA) and also demands the large dynamic range of digital to analog converter (DAC) at the transmitter. A number of schemes have been proposed to reduce the PAPR problem. The Discrete Fourier Transform (DFT) Spreading is one of the scheme to reduce the PAPR Problem in OFDM system. This paper presents the DFT spreading technique to reduce the PAPR problem. The PAPR reduction capability of this technique is demonstrated by presenting simulation results of PAPR.

Performance Analysis of PAPR Reduction Using DFT-Spreading OFDMA Technique

The 3GPP long term evolution (3GPP-LTE) has adopted the Discrete Fourier Transform Spreading Orthogonal Frequency Division Multiple Access (DFTS-OFDMA) technique to be used in the uplink air interface for the next generation cellular systems. The DFTS-OFDMA is also a candidate of radio interface technologies for the IMT-Advanced standards in ITU-R. This technique has been adopted for uplink transmission due to its attractive feature of lower PAPR archived by precoding data symbols using a DFT operation at the transmitter. In this paper, we analyse the performance of DFT-Spreading OFDMA technique in PAPR reduction by using the IFDMA and LFDMA subcarriers mapping modes. We also analyse the performance of the DFTS OFDMA technique for PAPR reduction as the number of subcarriers allocated to each user varies, specifically with the LFDMA subcarriers mapping mode. Simulation results show that, the IFDMA improves PAPR performance significantly than LFDMA with pulse shaping and wihout pulse ...

Performance Improvement of Papr Reduction For OFDM Signal in LTE System

International Journal of Wireless & Mobile Networks, 2013

Orthogonal frequency division multiplexing (OFDM) is an emerging research field of wireless communication. It is one of the most proficient multi-carrier transmission techniques widely used today as broadband wired & wireless applications having several attributes such as provides greater immunity to multipath fading & impulse noise, eliminating inter symbol interference (ISI), inter carrier interference (ICI) & the need for equalizers. OFDM signals have a general problem of high peak to average power ratio (PAPR) which is defined as the ratio of the peak power to the average power of the OFDM signal. The drawback of high PAPR is that the dynamic range of the power amplifier (PA) and digital-to-analog converter (DAC). In this paper, an improved scheme of amplitude clipping & filtering method is proposed and implemented which shows the significant improvement in case of PAPR reduction while increasing slight BER compare to an existing method. Also, the comparative studies of different parameters will be covered.

Peak-to-Average Power Ratio Analysis of SCFDMA Signal by Hybrid Technique

International Journal of Computer Applications, 2013

The low peak-to-average power ratio (PAPR) in single-carrier systems has motivated the Long Term Evolution (LTE) Third Generation Partnership Project (3GPP) to adopt single carrier frequency division multiple access (SC-FDMA) as the uplink multiple access scheme. In this paper, an enhancement of a SC-FDMA system by decreasing the PAPR is focused. A combination of clipping and Pulse shaping (RRC filter) is applied on a SC-FDMA signal with IFDMA subcarrier mapping, which results in a PAPR reduction. This PAPR reduction by hybrid (clipping & pulse shaping) technique can be used to enhance the power efficiency of the handset, or alternatively to improve uplink throughput and/or operating range.

Peak to Average Power Ratio Reduction in Single Carrier OFDMA Systems

International Conference on Aerospace Sciences and Aviation Technology

Single carrier frequency division multiple access (SC-FDMA) which utilizes single carrier modulation at the transmitter and frequency domain equalization at the receiver is a technique that has similar performance and essentially the same overall structure as those of an OFDMA system. One prominent advantage over OFDMA is that the SC-FDMA signal has lower peak-to-average power ratio (PAPR). SC-FDMA has drawn great attention as an attractive alternative to OFDMA, especially in the uplink communications where lower PAPR greatly benefits the mobile terminal in terms of the transmit power efficiency. SC-FDMA is currently a working assumption for the uplink multiple access scheme in 3GPP Long Term Evolution (LTE). To achieve low PAPR, a novel scheme, SC-OFDMA with super frame using intermediate mapping (SF-IFDMA), is proposed in this paper. In our proposed scheme, B frames with N subcarriers will be combined into one super frame, then SC-OFDM technique is applied to reduce the PAPR of the super frame, the super frame with lowered PAPR will finally be divided into B OFDM frames for the transmission. The combining and dividing process is equivalent to the concatenation process. The proposed scheme requires no side information and can significantly reduce PAPR while maintaining small number of subcarriers. Keywords: Single carrier OFDMA with intermediate mapping (IFDMA), IFDMA with super frame (SF-IFDMA), peak to average power ratio (PAPR).