scholarly journals Block Equalization for Single-Carrier Satellite Communications with High-Mobility Receivers

2007 ◽  
Author(s):  
L. Rugini ◽  
P. Banelli ◽  
M. Berioli
Keyword(s):  
High Mobility ◽  
Satellite Communications ◽  
Single Carrier

scholarly journals Orthogonal Time Sequency Multiplexing Modulation

2021 ◽  
Author(s):  
Tharaj Thaj ◽  
Emanuele Viterbo
Keyword(s):  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Performance ◽  
High Mobility ◽  
Low Complexity ◽  
Modulation Scheme ◽  
Frequency Space ◽  
Time Frequency ◽  
Single Carrier ◽  
The Time Domain

This paper proposes <i>orthogonal time sequency multiplexing</i> (OTSM), a novel single carrier modulation scheme based on the well known Walsh-Hadamard transform (WHT) combined with row-column interleaving, and zero padding (ZP) between blocks in the time-domain. The information symbols in OTSM are multiplexed in the delay and sequency domain using a cascade of time-division and Walsh-Hadamard (sequency) multiplexing. By using the WHT for transmission and reception, the modulation and demodulation steps do not require any complex multiplications. We then propose two low-complexity detectors: (i) a simpler non-iterative detector based on a single tap minimum mean square time-frequency domain equalizer and (ii) an iterative time-domain detector. We demonstrate, via numerical simulations, that the proposed modulation scheme offers high performance gains over orthogonal frequency division multiplexing (OFDM) and exhibits the same performance of orthogonal time frequency space (OTFS) modulation, but with lower complexity. In proposing OTSM, along with simple detection schemes, we offer the lowest complexity solution to achieving reliable communication in high mobility wireless channels, as compared to the available schemes published so far in the literature.

QoS-Constrained Resource Allocation Scheduling for LTE Network

2015 ◽  
Vol 4 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Hung-Chin Jang ◽  
Yun-Jun Lee
Keyword(s):  
Resource Allocation ◽  
Data Transmission ◽  
Orthogonal Frequency Division Multiplexing ◽  
Transmission Rate ◽  
High Mobility ◽  
System Throughput ◽  
Frequency Division ◽  
High Data ◽  
Single Carrier ◽  
Allocation Method

The goal of LTE (Long Term Evolution) is to provide high data transmission rate, scalable bandwidth, low latency, high-mobility, etc. LTE employs OFDM (Orthogonal Frequency Division Multiplexing) and SC-FDMA (Single Carrier - Frequency Division Multiple Access) for downlink and uplink data transmission, respectively. As to SC-FDMA, there are two constraints in doing resource allocation. First, the allocated resource blocks (RBs) should be contiguous. Second, those of the allocated RBs are forced to use the same modulation technique. The aim of this research is to propose a QoS-constraint resource allocation scheduling to enhance data transmission for uplink SC-FDMA. The proposed scheduling is a three-stage approach. In the first stage, it uses a time domain scheduler to differentiate user equipment (UE) services according to their distinct QoS service requirements. In the second stage, it uses a frequency domain scheduler to prioritize UE services based on channel quality. In the third stage, it limits the number of times of modulation downgrade of RBs allocation in order to enhance system throughput. In the simulations, the proposed method is compared to fixed sub-carrier dynamic resource allocation method and adaptive dynamic sub-carrier resource allocation method. Simulation results show that the proposed method outperforms the other two methods in terms of throughput, transmission delay, packet loss ratio, and RB utilization.

scholarly journals SC-FDE Layer for Sensor Networks in Remote Areas Using NVIS Communications

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1636
Author(s):  
Tomas Gonzalez ◽  
Joaquim Porte ◽  
Jordi Male ◽  
Joan Navarro ◽  
Josep M. Maso ◽  
...  
Keyword(s):  
Sensor Networks ◽  
Low Power ◽  
Large Scale ◽  
Satellite Communications ◽  
Physical Layer ◽  
Attractive Alternative ◽  
Remote Areas ◽  
Single Carrier ◽  
Ubiquitous Sensor Networks ◽  
Definition Of

Despite high costs and lengthy deployments, satellite communications have traditionally been used to provide coverage in remote areas. However, given the fact that there is no radio infrastructure available in these areas, Near Vertical Incidence Skywave (NVIS) technology has positioned itself as an attractive alternative to communicate with low-power nodes in remote areas. This type of communication works in the HF frequency range complying with STANAG and MIL-STD standards, which define a physical layer for scenarios that differ from NVIS and low-power communication. The purpose of this paper was to present the definition of a new communication physical layer based on single-carrier frequency-domain equalization (SC-FDE) based on these standards but adapted to the ionospheric communication channel. This physical layer was compared to an OFDM-based layer from a previous study. The experiments performed show that this new approach achieves better results than OFDM in terms of a higher signal quality with a higher specific BER probability. Finally, this layer was also used in the theoretical design of an NVIS gateway to link sensor network devices spanning large-scale remote areas in a secure manner in the context of ubiquitous sensor networks (USN).

scholarly journals Analysis of Phase Noise in a Hybrid Photonic/Millimetre-Wave System for Single and Multi-Carrier Radio Applications

2020 ◽  
Vol 10 (17) ◽  
pp. 5800 ◽  
Author(s):  
Devika Dass ◽  
Sean O'Duill ◽  
Amol Delmade ◽  
Colm Browning
Keyword(s):  
Phase Noise ◽  
Satellite Communications ◽  
Wave System ◽  
Receiver Design ◽  
60 Ghz ◽  
Error Vector Magnitude ◽  
Millimetre Wave ◽  
Future Evolution ◽  
Wave Phase ◽  
Single Carrier

The future evolution of wireless networks, throughout the 5G era and beyond, will require the expansion and augmentation of millimetre-wave systems for both terrestrial and satellite communications. Photonic technologies offer a cost efficient and high bandwidth platform for millimetre-wave carrier generation and distribution, but can introduce high levels of phase noise through optical heterodyning, which is highly problematic for mobile signal waveforms. In this work, a detailed analytical model of a hybrid photonic/mm-wave system is developed and discussed. Through careful system design, the system is found to support both 5G compatible multi-carrier (OFDM) and single carrier (APSK) modulation at 60 GHz. APSK is found to offer higher tolerance mm-wave phase noise compared to OFDM, ultimately easing optical linewidth restrictions to ∼30 kHz. The model is extended to include a novel millimetre wave phase noise cancelling receiver, which is shown to significantly alleviate these restrictions even further—enabling phase noise free mm-wave operation for optical linewidths up to ∼2 MHz. Detailed analysis and discussion of this extended system lead to the establishment of a theoretical relationship between the mm-wave receiver design and the achievable system performance in terms of error vector magnitude (EVM). Excellent matching of the predicted theoretical with simulated performances is shown.

scholarly journals Quasi-Orthogonal Time Division Multiplexing and Its Performances in Rayleigh Fading Channels

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Enchang Sun ◽  
Kechu Yi ◽  
Bin Tian ◽  
Dongying Zhang
Keyword(s):  
Fading Channels ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rayleigh Fading ◽  
Carrier Frequency Offset ◽  
Satellite Communications ◽  
Rayleigh Fading Channels ◽  
Transmission Scheme ◽  
Time Division Multiplexing ◽  
Single Carrier ◽  
Time Division

This paper proposes an efficient transmission scheme, Quasi-Orthogonal Time Division Multiplexing (QOTDM), which employs the shift orthogonal property of the pulse function with raised-cosine spectral shape, and the signal waveforms are quasi-orthogonal in time domain. Comparing to orthogonal frequency division multiplexing (OFDM), QOTDM is less sensitive to carrier frequency offset and power amplifier nonlinearities while keeping a similar spectral efficiency with OFDM due to single-carrier characteristics. QOTDM is a suitable consideration for the downlink transmission such as in satellite communications. An upper bound of sample error probability (SER) is derived to evaluate the performance of QOTDM. Comparisons of QOTDM and OFDM in Rayleigh fading channels show that the proposed QOTDM system is better than that of OFDM system in terms of bit error rate (BER) in high Eb/No regions.

scholarly journals Non-coherent massive MIMO-OFDM for communications in high mobility scenarios

2020 ◽  
Vol 1 (1) ◽  
pp. 13-24
Author(s):  
Kun Chen-Hu ◽  
Yong Liu ◽  
Ana Garcia Armada
Keyword(s):  
Fading Channels ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Mobility ◽  
Coherent Demodulation ◽  
Hardware Impairments ◽  
Single Carrier ◽  
High Power Amplifier ◽  
Reference Signals ◽  
Mimo Ofdm ◽  
The Impact

Under scenarios of high mobility, the traditional coherent demodulation schemes (CDS) have a limited performance, due to the fact that reference signals cannot effectively track the variations of the channel with an affordable overhead. As an alternative solution, non coherent demodulation schemes (NCDS) based on differential modulation have been proposed. Even in the absence of reference signals, they are capable of outperforming the CDS with a reduced complexity. The literature on NCDS laid the theoretical foundations for simplified channel and signal models, often single carrier and spatially uncorrelated flat fading channels. In this work, the most recent results assuming orthogonal frequency division multiplexing (OFDM) signaling and realistic channel models are explained, and the impact of some hardware impairments such as the phase noise (PN) and the non linear high power amplifier (HPA) are also considered. Moreover, new potential research lines are also highlighted.

scholarly journals Orthogonal Time Sequency Multiplexing Modulation

2021 ◽  
Author(s):  
Tharaj Thaj ◽  
Emanuele Viterbo
Keyword(s):  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Performance ◽  
High Mobility ◽  
Low Complexity ◽  
Modulation Scheme ◽  
Frequency Space ◽  
Time Frequency ◽  
Single Carrier ◽  
The Time Domain

This paper proposes <i>orthogonal time sequency multiplexing</i> (OTSM), a novel single carrier modulation scheme based on the well known Walsh-Hadamard transform (WHT) combined with row-column interleaving, and zero padding (ZP) between blocks in the time-domain. The information symbols in OTSM are multiplexed in the delay and sequency domain using a cascade of time-division and Walsh-Hadamard (sequency) multiplexing. By using the WHT for transmission and reception, the modulation and demodulation steps do not require any complex multiplications. We then propose two low-complexity detectors: (i) a simpler non-iterative detector based on a single tap minimum mean square time-frequency domain equalizer and (ii) an iterative time-domain detector. We demonstrate, via numerical simulations, that the proposed modulation scheme offers high performance gains over orthogonal frequency division multiplexing (OFDM) and exhibits the same performance of orthogonal time frequency space (OTFS) modulation, but with lower complexity. In proposing OTSM, along with simple detection schemes, we offer the lowest complexity solution to achieving reliable communication in high mobility wireless channels, as compared to the available schemes published so far in the literature.

scholarly journals Orthogonal Time Sequency Multiplexing Modulation

2021 ◽  
Author(s):  
Tharaj Thaj ◽  
Emanuele Viterbo
Keyword(s):  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Performance ◽  
High Mobility ◽  
Low Complexity ◽  
Modulation Scheme ◽  
Frequency Space ◽  
Time Frequency ◽  
Single Carrier ◽  
The Time Domain

This paper proposes <i>orthogonal time sequency multiplexing</i> (OTSM), a novel single carrier modulation scheme based on the well known Walsh-Hadamard transform (WHT) combined with row-column interleaving, and zero padding (ZP) between blocks in the time-domain. The information symbols in OTSM are multiplexed in the delay and sequency domain using a cascade of time-division and Walsh-Hadamard (sequency) multiplexing. By using the WHT for transmission and reception, the modulation and demodulation steps do not require any complex multiplications. We then propose two low-complexity detectors: (i) a simpler non-iterative detector based on a single tap minimum mean square time-frequency domain equalizer and (ii) an iterative time-domain detector. We demonstrate, via numerical simulations, that the proposed modulation scheme offers high performance gains over orthogonal frequency division multiplexing (OFDM) and exhibits the same performance of orthogonal time frequency space (OTFS) modulation, but with lower complexity. In proposing OTSM, along with simple detection schemes, we offer the lowest complexity solution to achieving reliable communication in high mobility wireless channels, as compared to the available schemes published so far in the literature.

scholarly journals Instalasi Mobile-VSAT dengan Modem Radyne Comstream Berbasis SCPC (Single Carrier Personal Carrier)

2017 ◽  
Vol 3 (2) ◽  
pp. 64
Author(s):  
Suci Rahmatia ◽  
Fitria Gani Sulistya
Keyword(s):  
Information Technology ◽  
Communication Technology ◽  
Human Life ◽  
Satellite Communications ◽  
Small Aperture ◽  
Earth Station ◽  
Single Carrier ◽  
Tremendous Impact

<p><em>Abstrak</em><strong> - Teknologi komunikasi akhir-akhir ini semakin mengarah ke unsur digital. Hal ini memberikan dampak yang luar biasa bagi kehidupan manusia terutama pada bagian informasi di pemerintahan. Banyak model telekomunikasi yang digunakan, ada yang paling sederhana yaitu melalui pesawat telepon, radio, dan satelit. Komunikasi satelit menggunakan perangkat satelit yang ada di luar angkasa sebagai jembatan informasinya dengan menggunakan pemancar stasiun bumi kecil VSAT (Very Small Aperture Terminal) yang membuat dua instansi dapat berkomunikasi dengan cepat dan akurat. Tulisan ini menjelaskan tentang instalasi mobile VSAT yang biasa digunakan di Biro Teknologi Komunikasi Divisi Teknologi Informasi MABES POLRI (ROTEKKOM Div TI MABES POLRI) untuk berkomunikasi. Biasanya bagian biro menyebut VSAT bergerak ini dengan KOMOBS. Bagian - bagian yang dibahas komponen alat, cara instalasi, dan konfigurasinya.</strong></p><p><strong> </strong></p><p><strong><em>Kata kunci : Satelit, VSAT, dan Instalasi</em></strong></p><p><strong><em> </em></strong></p><p><em>Abstract</em> <strong>- Communication technology lately is increasingly leading to digital elements. This has a tremendous impact on human life, especially on the part of information in government. Many telecommunication models are used, some of the simplest is through telephone, radio, and satellite. Satellite communications use existing satellite devices in space as a bridge of information by means of a small earth station transmitter VSAT (Very Small Aperture Terminal) which allows two agencies to communicate quickly and accurately. This paper describes the installation of mobile VSAT commonly used in the Bureau of Communication Technology Division of Information Technology MABES POLRI (ROTEKKOM Div IT MABES POLRI) to communicate. Usually the bureau section calls this moving VSAT with KOMOBS. The parts discussed are tool components, installation methods, and their configuration.</strong></p><p><strong> </strong></p><p><strong><em>Keywords: Satellite, VSAT, and Installation</em></strong></p>

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