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A parallel transmission scheme utilizing FDM is implemented by the use of a serial-to-parallel converter and multiple narrowband transmitters.
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This paper depicts the development of Orthogonal Frequency Division Multiplexing from a historical perspective. A summary of major research milestones are noted that contributed to modern-day OFDM. These contributions include the use of discrete Fourier transforms replacing the analog implementation and addition of cyclic extensions to ensure ortho...
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... serial-to- parallel converter divides the incoming message and outputs to multiple carriers. This is depicted in Fig 2. Compare a single wideband serial scheme using the same channel to a parallel transmission scheme. The parallel system will be more costly to implement than a single wideband transceiver. ...
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... An interesting characteristic of this system emerges when orthogonal sub-channels are used [14]. Orthogonality is achieved when all sub-channel data streams operate at a specified symbol rate 1 Ts , and the carrier frequency f c is an integer multiple of the symbol rate, i.e., f c = k Ts . ...
This paper describes an analog multi-tone receiver capable of processing three data streams running at 15 Gb/s, one in baseband and two in quadrature over carriers at 15GHz, achieving an aggregate rate of 45Gb/s over a single physical channel. The receiver maximizes bandwidth efficiency by using orthogonal sub-channels and avoids the need for analog to digital converters by incorporating a mixed-signal MIMO equalizer that can mitigate inter-symbol interference and inter-carrier interference. The system is designed and laid out in a 22nm FDSOI technology. Post-layout simulations are employed to verify the effectiveness of the proposed architecture, demonstrating a raw BER of 10-5 over a channel with an insertion loss of 14dB at 28GHz is achieved. The complete system has an energy efficiency of 6.6pJ/bit and occupies an active area of 0.29 mm2.
... The 5G and future transport networks are pointed to be highly demanding from spectral efficiency, as mentioned previously. The OFDM process is well known for its spectral efficiency in the electrical domain [25,26]. The full implementation of an OFDM signal at the optical domain has been shown as possible with PICs [16][17][18]27]. ...
This work presents the performance analysis of a passive optical network (PON) proposal with photonic integrated circuits (PIC). The PON architecture was simulated on MATLAB, focusing on the main functionalities of the optical line terminal, distribution network, and network unity regarded its effects on the physical layer. We show a simulated PIC, implemented on MATLAB through its analytic transfer function equation, used to implement orthogonal frequency division multiplexing in the optical domain to enhance the current optical networks for the 5G New-Radio (NR) scenario. We analyzed the OOK and optical PAM4 compared with phase modulation formats such as the DPSK and DQPSK. All modulation formats can be directly detected for the case in the study, simplifying the reception. Consequently, this work achieved a maximum symmetric transmission capacity of 1.2 Tbps over 90 km of standard single-mode fiber with 128 carriers, 64 carriers for downstream and 64 for upstream, obtained from an optical frequency comb with 0.3 dB flatness. We concluded that phase modulation formats associated with PIC could increase PON capability and push further our current scenario to the 5G new era.
... In proposed method, the work is done for the improvement of the signal for the given channel and to reduce the BER which further improves the channel estimation and its capability with hybrid optimization [6][7][8][9]. It also reduces error losses during the transmission from one end to the other end. ...
The performance of OFDM system depends on the how efficient channel estimation is, which directly impactsits bit error rate (BER). In this research work, the novel technique of pseudo-pilot aided OFDM system is usedits channel estimation with least square and Recursive Least Squares approach. In proposed technique, for channel estimation Pseudo-pilot technique is used in OFDM system over AWGN fading channels. A hybridization technique has been implemented to alleviate the error rate in the signals. The hybrid optimization approach is implemented on the estimated output for the optimum solution. The combination of the two optimization techniques is particle swarm optimization (PSO) and Moth Flame Optimization (MFO) method that is used for optimization of the performance rate. To get more optimum solutions (reducing BER) OFDM system is trained with neural network. The performance of the proposed techniques and the weighted scheme are compared and verified using computerized simulation carried out using Matrix Laboratory software. The hybrid approach is able to achieve low BER of the network. The BER of PSO is 1.004 × 10⁻⁷ whereas for hybrid optimization (PSO + MFO) BER is 6.275 × 10⁻⁸ at 18 dB SNR. After training of the whole system is done with BPNN which will further reduce the BER while increasing SNR. By using BPNN, BER will further reduce to 1.243 × 10⁻⁸ at 18 dB SNR. It means hybrid optimization is done to optimize the performance of the channel and reduce the BERs, which will help to increase the channel estimation process as well as channel capacity and further reduces the losses while transmission from one end to the other end.
... Orthogonal frequency division multiplexing (OFDM) is the most widely adopted transmission technology. Due to this technology's spectral efficiency, flexibility and scalability, high multiple-input multiple-output (MIMO) compatibility, low transceiver complexity, and robustness to frequency-selectivity, OFDM has been adopted in numerous wired 1 and wireless communications standards 2 [2]- [4], including 5G new radio (5GNR) [5], [6]. Despite such broad applicability and its efficient parallel transmission -via orthogonal subcarriers -by transforming a frequency selective channel to a frequency-flat channel (per a sub-channel), OFDM is sensitive to a timeselectivity [7], [8]. ...
... When a time-selectivity is compounded by a frequency-selectivity, a doubly selective fading channel [9], [10] arises. During this channel's filtering of the transmitted OFDM 1 OFDM-based wired communications standards: Asymmetric Digital Subscriber Line (ADSL); Very high-speed Digital Subscriber Line (VDSL); Digital Video Broadcasting -Cable (DVB-C); DVB-C2; Multimedia Over Coax Alliance (MoCA) home networking; Data Over Cable Service Interface Specification (DOCSIS); and so on [1]. 2 OFDM-based wireless communications standards: the wireless local area network (WLAN) radio interfaces such as IEEE 802.11a, g, n, ac, ah, and HIPERLAN/2; Digital Video Broadcasting -Terrestrial (DVB-T); Digital Video Broadcasting -Handheld (DVB-H); evolved UMTS Terrestrial Radio Access (E-UTRA); the 4G downlink of the 3GPP Long Term Evolution (LTE) standard; the wireless MAN/broadband wireless access (BWA) standard IEEE 802.16e (Mobile-WiMAX); and alike [1]. symbols, orthogonality among the subcarriers can be destroyed to an extent that OFDM would suffer from a severe intercarrier interference (ICI). ...
... When a time-selectivity is compounded by a frequency-selectivity, a doubly selective fading channel [9], [10] arises. During this channel's filtering of the transmitted OFDM 1 OFDM-based wired communications standards: Asymmetric Digital Subscriber Line (ADSL); Very high-speed Digital Subscriber Line (VDSL); Digital Video Broadcasting -Cable (DVB-C); DVB-C2; Multimedia Over Coax Alliance (MoCA) home networking; Data Over Cable Service Interface Specification (DOCSIS); and so on [1]. 2 OFDM-based wireless communications standards: the wireless local area network (WLAN) radio interfaces such as IEEE 802.11a, g, n, ac, ah, and HIPERLAN/2; Digital Video Broadcasting -Terrestrial (DVB-T); Digital Video Broadcasting -Handheld (DVB-H); evolved UMTS Terrestrial Radio Access (E-UTRA); the 4G downlink of the 3GPP Long Term Evolution (LTE) standard; the wireless MAN/broadband wireless access (BWA) standard IEEE 802.16e (Mobile-WiMAX); and alike [1]. ...
We provide a new generation solution to the fundamental old problem of a doubly selective fading channel estimation for orthogonal frequency division multiplexing (OFDM) systems. For systems based on OFDM, we propose a deep learning (DL)-based blind doubly selective channel estimator. This estimator does require no pilot symbols, unlike the corresponding state-of-the-art estimators, even during the estimation of a deep fading doubly selective channel. We also provide the first of its kind theory on the testing mean squared error (MSE) performance of our investigated blind OFDM channel estimator based on over-parameterized ReLU FNNs.
... The implementation of the OFDM system is based on Inverse Fast Fourier Transform (IFFT) and Fast Fourier Transform (FFT) for the modulation and the demodulation, respectively [4]. In this paper, we adopt the Long Term Evolution (LTE), that is one of the communication standards based on the OFDM system, especially for downlink transmission. ...
The growing demand for wireless devices capable of performing complex communication processes has imposed an urgent need for high-speed communication systems and advanced network processors. This paper proposes a hardware workflow developed for the Long-Term Evolution (LTE) communication system. It studies the multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) LTE system. Specifically, this work focuses on the implementation of the OFDM block that dominates the execution time in high-speed communication systems. To achieve this goal, we have proposed an NoC-based low-latency OFDM LTE multicore system that leverages Inverse Fast Fourier Transform (IFFT) parallel computation on a variable number of processing cores. The proposed multicore system is implemented on an FPGA platform using the ProNoC tool, an automated rapid prototyping platform. Our obtained results show that LTE OFDM execution time is drastically reduced by increasing the number of processing cores. Nevertheless, the NoC’s parameters, such as routing algorithm and topology, have a negligible influence on the overall execution time. The implementation results show up to 24% and 76% execution time reduction for a system having 2 and 16 processing cores compared to conventional LTE OFDM implemented in a single-core, respectively. We have found that a 4×4 Mesh NoC with XY deterministic routing connected to 16 processing tiles computing IFFT task is the most efficient configuration for computing LTE OFDM. This configuration is 4.12 times faster than a conventional system running on a single-core processor.
... Consider a correspondence connect with nT sending radio wires and nR getting recieving wires. Some significant suspicions are made [2]: 1) There is just a solitary client sending at some random time, so they got signal is adulterated by AWGN (Additive White Gaussian Noise) as it were. ...
The motivation behind this paper is to present another technique for isolating remote correspondence, (for example, the 802.11a/b/g/n and cell UMTS MAC conventions) across numerous problematic correspondence joins (like Ethernet) utilizing milli meter waves MIMO correspondence. The object is to present the fitting equipment, programming, and framework design needed to give the premise to a remote framework (utilizing a 802.11a/b/g/n and cell conventions as a model) that can scale to help a huge number of clients at the same time (say in a huge place of business, super corporate retailer, and so forth) or in a little, however extremely thick correspondence RF area. Components of correspondence between a base station and a Mobile Station will be examined measurably to exhibit higher throughput, less crashes and lower bit mistake rates (BER) with the given transmission capacity characterized by the 802.11n remote detail (utilization of MIMO channels will be assessed). Another organization nodal worldview will be introduced. Elective connection layer correspondence strategies will be suggested and broke down for the impact on cell phones. The examination will depict how the calculations utilized by state machines executed on Mobile Stations and Wi-Fi customer gadgets will be impacted by new base station transmission conduct. New equipment plan strategies that can be utilized to improve this engineering just as equipment plan standards concerning the insignificant equipment practical squares needed to help such a framework configuration will be portrayed. Recreation plan and check reproduction procedures to demonstrate the plan will oblige a worthy degree of execution to meet the exacting planning as it identifies with this new framework engineering.
... The concept of OFDM was designed in earlier 1960s; it was not able to be achieved until the emergence of Fast Fourier transform (FFT) with the emergence of inverse Fast Fourier transform (IFFT) was made possible to generate OFDM using the digital domain for orthogonality of sub carriers [3]. The idea of using Multi-Carrier High-speed data rates technologies such as OFDM parallel-data transmission and frequency division multiplexing (FDM) was earliest initiated in the middle of 1960s [8]. The basic concept was to make used of parallel data and OFDM with overlapping sub-channels to avoid the used of higher speed equalization to avoid impulse noise and multiphase distortion and fully utilize bandwidth. ...
Orthogonal Frequency Division Multiplexing (OFDM) is used to enhance Bit Error Rates (BER) performance for error free transmission in free space in free pace. OFDM-based systems operate in the hostile multipath radio environment, which allows efficient sharing of limited resources. This research work was designed, developed and simulated an FFT-OFDM based System using the basic blocks of Simulink in MATLAB/Simulink software, to enhance BER for error free transmission. The system was design using Fast Fourier transform (FFT) and Inverse Fast Fourier transform (IFFT). This was achieved in backing of collection and review of high-quality research papers, which reported the latest research developments in OFDM communications networks, and its applications in future wireless systems. The research mitigated the noise enhancement effect. And many critical problems associated with the error transmission in wireless communication networks in the future. An error transmission in wireless systems is global issues and challenges that are still looking for efficient solutions. This research work would overcome the global issues and challenges facing the wireless communication network.
... This access scheme is known as orthogonal frequency division multiple access (OFDMA) with cyclic prefix (CP). The scheme addresses the problem of bandwidth wastage encountered in FDMA schemes by the overlapping of the orthogonal sub-channels [3,8]. The introduced CP in this scheme is used to offer robustness against the harmful effects of multipath fading and it is usually implemented based on inverse fast Fourier transform/fast Fourier transform (IFFT/FFT) [9]. ...
The advancement in wireless communication applications encourages the use of effective and efficient channel estimation (CE) techniques because of the varying behaviour of the Rayleigh fading channel. In most cases, the emphasis of most proposed CE schemes is to improve the CE performance and complexity for ensuring quality signal reception and improved system throughput. Candidate waveforms whose designs are based on filter bank multi-carrier (FBMC) modulation techniques such as filter bank orthogonal frequency division multiplexing based on offset quadrature amplitude modulation (OFDM-OQAM), universal filtered multicarrier (UFMC) and generalised frequency division multiplexing based on offset quadrature amplitude modulation (GFDM-OQAM) are no exception to the use of these proposed CE techniques in the literature. These schemes are considered as potential waveform candidates for the physical/media access control layer of the emerging fifth generation (5G) networks. Therefore, pinpoint CE techniques represent an important requirement for these waveforms to attain their full potentials. In this regard, this paper reviews the concept of CE as applicable to these waveforms as well as other waveform candidates under consideration in the emerging 5G networks. Since the design of the majority of the waveform candidates is filter based, a review of the general filter design considerations is presented in this paper. Secondly, we review general CE techniques for candidate waveforms of next generation networks and classify some of the studied CE techniques. In particular, we classify the CE schemes used in filter bank OFDM-OQAM and GFDM-OQAM based transceivers and present a performance comparison of some of these CE schemes. Besides, the paper reviews the performances of two linear CE schemes and three adaptive based CE schemes for two FBMC based waveform candidates assuming near perfect reconstruction (NPR) and non-perfect reconstruction (Non-PR) filter designs over slow and fast frequency selective Rayleigh fading channels. The results obtained are documented through computer simulations, where the performances of the studied CE schemes in terms of the normalised mean square error (NMSE) are analysed. Lastly, we summarise the findings of this work and suggest possible research directions in order to improve the potentials of the studied candidate waveforms over Rayleigh fading channels.
... The progressive growth of internet in terms of high speed data rate for complex signal processing application such as 4G and 5G is rapidly increasing, to met with this challenge, service providers are continuously trying new technology, for them bandwidth allocation is a precious commodity, and therefore OFDM is used [4]. It is an extension to its prior technology Frequency Division Multiplexing (FDM) which is a single carrier system, however with OFDM it is now Multi-Carrier system which is first proposed by Weinstein and Ebert with Discrete Fourier Transform (DFT), although it was Chang [5] who first proposed OFDM in a practical aspect. ...
... Channel equalization is simplified because OFDM may be viewed as using many slowly modulated narrowband signals rather than one rapidly modulated wideband signal. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate ISI and utilize multipath "echoes" and time-spreading to achieve a diversity gain, i.e., a signal-tonoise ratio improvement [74]. ...
The use of aeronautical vehicles and systems is continuously growing, and this means current aeronautical communication systems, particularly those operating in the very high frequency (VHF) aviation band, will suffer from severe congestion in some regions of the world. For example, it is estimated that air-to-ground (AG) communication traffic density will at least double by 2035 over that in 2012, based on the most-likely growth scenario for Europe. This traffic growth (worldwide) has led civil aviation authorities such as the FAA in the USA, and EuroControl in Europe, to jointly explore development of future communication infrastructures (FCI). According to international aviation systems policies, both current and future AG communication systems will be deployed in L-band (960-1164 MHz), and possibly in C-band (5030-5091 GHz) because of the favorable AG radio propagation characteristics in these bands. During the same time period as the FCI studies, the use of multicarrier communication technologies has become very mature for terrestrial communication systems, but for AG systems it is still being studied and tested.
Aiming toward future demands, EuroControl and FAA sponsored work to define several new candidate AG radio systems with high data rate and high reliability. Dominant among these is now an L-Band Digital Aeronautical Communication Systems (L-DACS): L-DACS1. L-DACS1 is a multicarrier communication system based on the popular orthogonal frequency division multiplexing (OFDM) modulation technique. For airport surface area communication systems used in C-band, EuroControl and FAA also proposed another OFDM communication system based on the IEEE 802.16e standard, termed aeronautical mobile airport communication system (AeroMACS). This system has been proposed to provide the growing need of communication traffic in airport environments.
In this dissertation, first we review existing and proposed aviation communication systems in VHF-band, L-band and C-band. We then focus our study on the use of multicarrier techniques in these aviation bands. We compare the popular and dominant multicarrier technique OFDM (which is used in cellular networks such long-term evolution (LTE) and wireless local area networks such as Wi-Fi) with the filterbank multicarrier (FBMC) technique. As far as we are aware, we are the first to propose and evaluate FBMC for aviation communication systems.
We show, using analysis and computer simulations, along with measurement based (NASA) air-ground and airport surface channel models, that FBMC offers advantages in performance over the OFDM schemes. Via use of sharp filters in the frequency domain, FBMC reduces out of band interference. Specifically, it is more robust to high-power distance measurement equipment (DME) interference, and via replacement of guard bands with data-bearing subcarriers, FBMC can offer higher throughput than the contending L-DACS1 scheme, by up to 23%. Similar advantages over AeroMACS pertain in the airport surface channel. Our FBMC bit error ratio performance is comparable to that of the OFDM schemes, and is even better for our “spectrally-shaped” version of FBMC. For these improvements, FBMC requires a modest complexity increase.
Our final contribution in this dissertation is the presentation of spectrally shaped FBMC (SS-FBMC). This idea allocates unequal power to subcarriers to contend with non-white noise or non-white interference. Our adaptive algorithm selects a minimum number of guard subcarriers and then allocates power accordingly to remaining subcarriers based on a “water-filling-like” approach. We are the first to propose such a cognitive radio technique with FBMC for aviation applications. Results show that SS-FBMC improves over FBMC in both performance and throughput.
