scholarly journals Estimation Techniques for MIMO-OFDM-A Review

2021 ◽  
pp. 409-414
Author(s):  
Varsha Yadav ◽  
Prashant Garg
Keyword(s):  
Power Efficiency ◽  
Multiple Access ◽  
Average Power ◽  
Frequency Division ◽  
Mobile Terminals ◽  
3Gpp Lte ◽  
Synchronization Errors ◽  
Single Carrier ◽  
Moderate Power ◽  
Code Division Multiple

In the context of Third-Generation Partnership Project Long-Term Evolution (3GPP LTE), the target data rates are 100 Mb/s in downlink and 50 Mb/s in uplink, and other system features include flexible bandwidths and moderate power consumption of mobile terminals. While the previous 3GPP generations, namely, 3G UMTS and 3.5G HSPA, rely on code-division multiple access (CDMA), LTE adopts orthogonal frequency-division multiple access (OFDMA)-based technologies for its uplink and downlink. Due to high peak-to-average power ratio (PAPR) of OFDMA signals, the single- carrier frequency division multiple access (SC-FDMA), also known as discrete Fourier transform (DFT)-spread OFDMA, has been selected for the uplink transmission in 3GPP LTE systems. SC-FDMA has similar throughput performance as OFDMA but with lower PAPR to increase power efficiency and is less sensitive to frequency synchronization errors, which makes it favorable for mobile terminals.

NOVEL MULTIPLE LEVEL SUBCARRIER ALLOCATION SCHEME IN SC-FDMA FOR LTE-A UPLINK

2016 ◽  
Vol 78 (8) ◽  
Author(s):  
Mohamed Melood A. Abdased ◽  
Mahamod Ismail ◽  
Rosdiadee Nordin
Keyword(s):  
Multiple Access ◽  
Average Power ◽  
Frequency Division ◽  
Robust Performance ◽  
Frequency Allocation ◽  
Single Carrier ◽  
Term Evolution ◽  
Lower Complexity ◽  
Papr Performance

Long Term Evolution-Advanced (LTE-A) uses Single-Carrier Frequency Division Multiple Accesses (SC-FDMA) for uplink, because it has robust performance against the Peak Average Power Ratio (PAPR), compared to Orthogonal Frequency Division Multiple Access (OFDMA). SC-FDMA schemes include Interleaved FDMA (IFDMA) and Localized FDMA (LFDMA), both of which are commonly practiced in LTE-A uplink. IFDMA allocates distributed frequency carriers for users, whereas LFDMA allocates localized frequency carriers for users. The frequency allocation in an IFDMA scheme exhibits better PAPR performance, whereas the advantage of LFDMA is its lower complexity requirements. In this paper, a new scheme is introduced that integrates IFDMA and LFDMA by using a variable interleave allocation of subcarriers in the bandwidth. Here, Generalized Interleaved Frequency Division Multiple Accesses (GIFDMA), is used as a master key that controls the allocation for interleaved and localized FDMA, also known as L/I FDMA. This integration of IFDMA and LFDMA has been derived theoretically and empirically. Simulations are conducted to investigate the effect of different parameters on the GIFDMA PAPR performance, which is compared to that of conventional IFDMA and LFDMA. The simulation results revealed that the proposed GIFDMA provides PAPR performance comparable to that of both LFDMA and IFDMA.

scholarly journals MULTIPLE-ACCESS TECHNOLOGY OF CHOICE IN 3GPP LTE

2013 ◽  
Vol 6 (2) ◽  
pp. 321-328
Author(s):  
Ibikunle Frank ◽  
Dike Ike ◽  
Ajayi Jimi ◽  
Onasoga Kayode
Keyword(s):  
Network Architecture ◽  
Multiple Access ◽  
Access Network ◽  
Performance Comparison ◽  
Frequency Division ◽  
Mobile Broadband ◽  
3Gpp Lte ◽  
Single Carrier ◽  
Radio Access ◽  
Air Interface

Third-Generation Partnership Project (3GPP) standardizes an Evolved UMTS Terrestrial Radio Access Network (EUTRAN)as air interface in its release 8 LTE. Orthogonal Frequency Division Multiple Access(OFDMA) and Single Carrier-Frequency Division Multiple Access(SC-FDMA)are key technologies for the air interface of mobile broadband systems.It is evident that mobile broadband access technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with OFDMA based air interface technology. The air interface of E-UTRAN is based on OFDMA in downlink and SC-FDMA in the uplink, making it possible to efficientl utilize bandwidth due to the orthogonally between sub-carriers and by assigning subsets of sub-carriers to individual users which allows for simultaneous data rate transmission from several users and differentiated quality of service for each user. In this paper, wehighlight the technologies behindOFDMA and SC-FDMA and also carry out performance comparison of the two air interface technologies. We brieflydescribe the 3GPP LTE standard, and its implementation using OFDMA and SC-FDMA technology.

scholarly journals PAPR Analysis of Fifth Generation Multiple Access Waveforms for Advanced Wireless Communication

2018 ◽  
Vol 7 (3.34) ◽  
pp. 487 ◽  
Author(s):  
Kommabatla Mahender ◽  
Tipparti Anil Kumar ◽  
K S Ramesh
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Average Power ◽  
Cumulative Distribution ◽  
Fourth Generation ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Single Carrier

This paper describes the aspects of multiple access for emerging (5G) Wireless Communication Systems. Orthogonal Frequency Division Multiplexing (OFDM) is best suited for fourth generation (4G) but it suffers from the problem of high Peak to Average Power Ratio (PAPR) & Side band leakage. Single carrier frequency division multiple access (SC-FDMA) has worked like an alternative to OFDMA only in the uplink process and PAPR was reduced. OFDM based 4G network is not capable of supporting diverse applications and these applications can be implemented by 5G.  High traffic requirements of 5G can be evaluated by using multiple access schemes, namely filter-bank multi-carrier (FBMC), universal-filtered multi-carrier (UFMC), generalized frequency-division multiplexing (GFDM). Comparison of PAPR reduction is done based on Complementary Cumulative Distribution Function (CCDF), for various multiple access 5G waveforms.  

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