scholarly journals Performance analysis of OFDMA and SC-FDMA

2017 ◽  
Vol 8 (2) ◽  
pp. 113-116 ◽  
Author(s):  
M. Al-Rawi
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
High Speed ◽  
Minimum Mean Square Error ◽  
Frequency Division ◽  
International Telecommunication Union ◽  
Single Carrier ◽  
Main Challenge ◽  
Better Than

The main challenge in any high-speed digital communication system is how to maximize the data rate with minimizing the bit error rate. Several techniques have been developed to achieve this point. Some of these techniques are orthogonal frequency division multiplexing (OFDM), single-carrier frequency domain equalization (SC-FDE), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA). These four techniques are described briefly in this paper. Also, the paper measures the performances of OFDMA and SC-FDMA systems over international telecommunication union (ITU) vehicular-A channel using minimum mean square error (MMSE) equalization. Simulation results show that the performances with interleaved mapping outperform that with localized mapping. Also, the performances with quadrature phase shift keying (QPSK) are better than that with 16-ary quadrature amplitude modulation (16QAM). In addition, the performance of SC-FDMA is better than that of OFDMA, when QPSK is used, but the latter is little bit better than that of SC-FDMA when 16QAM is used.

scholarly journals Distributed Space-Time/Frequency Coding Schemes for Single-Carrier Frequency Division Multiple Access Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-10
Author(s):  
A. Y. Al-nahari ◽  
F. E. Abd El-Samie ◽  
M. I. Dessouky
Keyword(s):  
Fading Channels ◽  
Carrier Frequency ◽  
Multiple Access ◽  
Minimum Mean Square Error ◽  
Average Power ◽  
Spatial Diversity ◽  
Space Time ◽  
Frequency Division ◽  
Time Frequency ◽  
Single Carrier

The single carrier-frequency division multiple access (SC-FDMA) system is a new system that was adopted in the standardization of the upcoming 3GPP long-term evolution (LTE). Designing diversity-achieving schemes for the SC-FDMA system is a challenging task. The codes adopted should not affect the peak-to-average power ratio (PAPR) among other constraints. In this paper, we consider the design of cooperative diversity schemes for SC-FDMA systems in the uplink direction. Specifically, two relay-assisted distributed space-time/frequency codes are proposed. The proposed distributed space-frequency code (SFC) achieves full spatial diversity in the uplink fast-fading channels, where a diversity of order three can be achieved. The proposed code keeps a low PAPR, which is a good feature of the system. A minimum mean square error (MMSE) decoder is used at the receiver of the destination node. Moreover, we propose a bandwidth-efficient distributed space-time code (STC) for slow-fading relay channels. A decode-and-forward (DF) protocol is used at the relay node, and the possibility of erroneous decoding is taken into account. Simulation results demonstrate the performance improvement of the proposed schemes.

A Novel Reconfigurable Orthogonal Frequency Division Multiplexing Transceiver

2019 ◽  
Vol 16 (2) ◽  
pp. 430-435
Author(s):  
N. Girinath
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Frequency Division Multiplexing ◽  
Path Delay ◽  
Frequency Division ◽  
Channel Fading ◽  
High Data ◽  
Digital World ◽  
Single Carrier ◽  
Selective Mapping

As the world moves toward 3G/4G there is a need for high data rate and relatively wide bandwidths. OFDM (Orthogonal Frequency Division Multiplexing) a form of multicarrier modulation technique is widely used to achieve high speed efficient data transmission at the rate of several Mbps. It is used in Wi-Fi standards like 802.11a, 802.11n, 802.11ac, broadcast standards like Digital Video Broadcast (DVB) and cellular telecommunications standard LTE. The main advantage of OFDM compared to single carrier modulation is their robustness to channel fading in wireless environment, high baud rates and less inter symbol interference. One major disadvantage is its High PAPR. PTS partial transmit sequences (PTS) and selective mapping are proposed to reduce it. Since FFT is core block of OFDM it must be able to adapt itself to ever changing digital world. A function specific reconfigurable 2k SDF (Single path delay feedback) FFT is proposed. It utilizes less power and can be configured for different FFT sizes ranging from 16-point to 1024-point. The validity and efficiency of the architecture have been verified by simulation in hardware description language VERILOG and targeted on Virtex-6 device. Finally PAPR is estimated by MATLAB simulation.

Next Generation Wireless Multiple Access Technology OFDMA and SC - FDMA Performance Analysis

2013 ◽  
Vol 336-338 ◽  
pp. 1670-1675
Author(s):  
Lin Wan
Keyword(s):  
Multiple Access ◽  
System Capacity ◽  
Frequency Division ◽  
Theoretical Derivation ◽  
Access Technology ◽  
Single Carrier ◽  
Access Scheme ◽  
Basic Performance ◽  
Better Than

orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC - FDMA) are the two kinds of 4 g wireless multiple access scheme. In the long term evolution (LTE) downlink link access scheme based on OFDMA, at the same time, the uplink access scheme based on SC - FDMA. In this article, we deduced the OFDMA and SC - FDMA basic performance difference, and then demonstrates the comprehensive performance comparisons between them. Theoretical derivation results show that the system capacity is better than that of SC - FDMA OFDMA. Then, we use the numerical simulation results confirm the conclusion. Keywords: OFDMA SC - FDMA basic capacity of the uplink transmission

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