Frequency Allocation for Wireless Fidelity (Wi-Fi) System using FDMA

2021 ◽  
Vol 6 (4) ◽  
pp. 01-09
Author(s):  
Kumar Mohan ◽  
◽  
Vara Prasad Reddy ◽  
Keyword(s):  
Multiple Access ◽  
Considerable Improvement ◽  
Frequency Division ◽  
Frequency Allocation ◽  
Large Size ◽  
Core Technology ◽  
Access Scheme ◽  
Multiple Access Schemes ◽  
System Frequency ◽  
Wireless Fidelity

As a core technology enabling factor for the next generation, it is provided to benefit cellular modems, wireless fidelity (Wi-Fi), multi-user seamless access. Recommend a fiction in this paper, multiple access scheme based on frequency-domain referred to as the frequency division multiple access (FDMA). Our studies indicate that FDMA represents a considerable improvement in spectral efficiency. In two variables, roughly equivalent to ordinary multiple access schemes, the hardware and computational complexity were being questionably presented. FDMA is one of the multiple access scheming which deals with the frequency of the system. Frequency allocation in the system or between the system plays an important role while transmitting and receiving the large size bits. While transmitting or receiving the large size bits, frequency allocation must be needed. To transmit the large bits, the frequency allocation should also be large, so that without any noise or interference, the transmitter can send the bits in allocated frequency. Not only does the transmitter, transmit the large bits, the receiver also receives the large-sized bits in allocated frequency. So that, this paper introduces the FDMA technique in Wireless Fidelity (Wi-Fi).

scholarly journals NOMA for Multinumerology OFDM Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ayman T. Abusabah ◽  
Huseyin Arslan
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Superposition Coding ◽  
Promising Technique ◽  
Successive Interference Cancelation ◽  
Power Domain ◽  
Multiple Access Schemes ◽  
Spectrally Efficient

Nonorthogonal multiple access (NOMA) is a promising technique which outperforms the traditional multiple access schemes in many aspects. It uses superposition coding (SC) to share the available resources among the users and adopts successive interference cancelation (SIC) for multiuser detection (MUD). Detection is performed in power domain where fairness can be supported through appropriate power allocation. Since power domain NOMA utilizes SC at the transmitter and SIC at the receiver, users cannot achieve equal rates and experience higher interference. In this paper, a novel NOMA scheme is proposed for multinumerology orthogonal frequency division multiplexing system, that is, different subcarrier spacings. The scheme uses the nature of mixed numerology systems to reduce the constraints associated with the MUD operation. This scheme not only enhances the fairness among the users but improves the bit error rate performance as well. Although the proposed scheme is less spectrally efficient than conventional NOMA schemes, it is still more spectrally efficient than orthogonal multiple access schemes.

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

scholarly journals Performance Analysis of OFDMA vs. NOMA in Cognitive Radio Network

2021 ◽  
Vol 9 (VI) ◽  
pp. 2483-2488
Author(s):  
E. Alwin Richard
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Spectrum Efficiency ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Time Frequency ◽  
New Class ◽  
Overlapping Data ◽  
Multiple Access Schemes

Recent advancements in communication systems have resulted in a new class of multiple access schemes known as non-orthogonal multiple access (NOMA), the primary goal of which is to increase spectrum efficiency by overlapping data from different users in a single time-frequency resource used by the physical layer. NOMA receivers can resolve interference between data symbols from various users, hence increasing throughput. Initially, the combination of SCMA and orthogonal frequency division multiplexing (OFDM) is addressed, establishing a baseline for the overall SER performance of the multiple access strategy. Furthermore, this work suggests the merging of SCMA with generalised frequency division multiplexing (GFDM).GFDM is an intriguing possibility for future wireless communication systems since it is a very flexible non-orthogonal waveform that can imitate various different waveforms as corner cases. This research suggests two methods for integrating SCMA with GFDM.

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 Under Test Filtered-OFDM And UFMC 5g Waveform Using Cellular Network

2019 ◽  
Vol 54 (5) ◽  
Author(s):  
Ahmed Talaat Hammoodi ◽  
Farooq Sijal Shawqi ◽  
Lukman Audaha ◽  
Abdullah Ali Qasim ◽  
Ammar Ahmed Falih
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Average Power ◽  
Cyclic Prefix ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Wireless Technology ◽  
Spectrum Utilization ◽  
Multiple Access Schemes ◽  
Modulation Methods

In this study, filtered orthogonal frequency division multiplexing (F-OFDM) and universal filtered multicarrier (UFMC) were proposed for complexity reduction in the 5G waveform. Cyclic prefix orthogonal frequency division multiplexing (CP_OFDM) is well suited for 4G; however, the major problem of the 4G modulation methods is their susceptibility to high peak to average power ratio (PAPR). Another problem of OFDM is the issue of sideband leakage. The existing 4G systems mainly depend on the CP_OFDM waveform, which cannot support the host of applications provided by the 5G platform. 5G-generated traffic is likely to exhibit different features and requirements compared to the existing wireless technology. Consequently, investigations have been devoted to other multiple access schemes. The existing limitations of OFDM can be mitigated by using the UFMC technique. To ensure that the demands and requirements of the upcoming 5G cellular networks are satisfied, this study presents an enabler called filtered-OFDM (f-OFDM) for flexible waveform configurations. Contrarily, the assigned bandwidth in the f-OFDM is split into various sub-bands to accommodate different services in each sub-band using the most suited waveform, thereby enhancing the spectrum utilization using a different filter. Additionally, the advantages of F-OFDM and UFMC were portrayed via a wide comparison with the current 5G waveforms.

scholarly journals Spectrum-Efficient Cognitive Radio Transceiver Using Multiwavelet Filters

2012 ◽  
Vol 2012 ◽  
pp. 1-13
Author(s):  
Manju Mathew ◽  
A. B. Premkumar ◽  
A. S. Madhukumar
Keyword(s):  
Cognitive Radio ◽  
Mobile Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Frequency Division ◽  
Error Performance ◽  
Promising Candidate ◽  
Access Scheme ◽  
Radio Transceiver ◽  
Adequate Data

Cognitive radio (CR) transceiver that can offer adequate data rate and multiuser support for future wireless networks is a promising technology for reliable and spectrum-efficient mobile communication. Orthogonal frequency division multiplexing (OFDM) and scalar wavelet based schemes have been proposed as physical layer techniques for CR. This paper proposes multiwavelet packet-based multicarrier multiple-access scheme as an equally promising candidate for multi-user CR networks and using existing orthonormal multiwavelets, the performance of the proposed system is evaluated. It is shown that the error performance of the proposed system under frequency and phase offset conditions is comparable with existing schemes.

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