This paper proposes an optical spatial modulation (OSM) technique to enhance the data rate of indoor optical wireless communication systems. OSM works by activating only one out of multiple light emitting diodes at each time instant to transmit data. The paper shows that properly aligning the positions and orientations of the transmit and receive units can significantly improve the performance of OSM by decorrelating the optical MIMO channel. Through alignment, the paper achieves a 14 dB gain in signal-to-noise ratio required for a bit-error rate of 10^-3 compared to misaligned setups. The paper also compares the power and bandwidth efficiency of OSM to on-off keying, pulse position modulation, and pulse amplitude modulation.
Optical Spatial Modulation OFDM using Micro LEDsBasil Jacob
An insight into the latest technology that could become the corner stone of Li-Fi technology. It mainly compares the OSM-OFDM with Optical Spatial Multiplexing OFDM based on the reference publications.
This presentation describes role of orthogonal division mutiplexing in optical networks and electrical networks. It starts with introduction ofdm tecnique then move to role of OFDM in Electrical domain then optical domain
Concept of Flip OFDM and its applicationsDarshan Bhatt
OFDM is the advanced FDM technique used for wireless communication. But for Uni-polar communication and Optical Wireless communication (OWC) its modified version called Flip OFDM is quiet efficient technique.
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
Optical Spatial Modulation OFDM using Micro LEDsBasil Jacob
An insight into the latest technology that could become the corner stone of Li-Fi technology. It mainly compares the OSM-OFDM with Optical Spatial Multiplexing OFDM based on the reference publications.
This presentation describes role of orthogonal division mutiplexing in optical networks and electrical networks. It starts with introduction ofdm tecnique then move to role of OFDM in Electrical domain then optical domain
Concept of Flip OFDM and its applicationsDarshan Bhatt
OFDM is the advanced FDM technique used for wireless communication. But for Uni-polar communication and Optical Wireless communication (OWC) its modified version called Flip OFDM is quiet efficient technique.
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
Performance Analysis of Massive MIMO Downlink System with Imperfect Channel S...IJRES Journal
We investigate the ergodic sum rate and required transmit power of a single-cell massive
multiple-input multiple-output (MIMO) downlink system. The system considered in this paper is based on two
linear beamforming schemes, that is, maximum ratio transmission (MRT) beamforming and zero-forcing (ZF)
beamforming. What’s more, we use minimum mean square error (MMSE) channel estimation to get imperfect
channel state information (CSI). Compared with the perfect CSI case, both theoretical analysis and simulation
results show that the system performance is different when the imperfect CSI is taken into account.
MIMO radar is introduced in presentation ,its advantage .future scope,research area.
MIMO radars represent a new generation of radars. In contrast to the traditional phased-array radar in which the transmit elements can transmit only the scaled versions of same signal, a MIMO radar allows the transmitters to transmit multiple signals. This waveform diversity offers enhanced flexibility in transmit beampattern synthesis which is an important area of MIMO radar signal processing
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM )BhaSkar Nath
Principle of orthogonal frequency-division multiplexing (OFDM)
Optical transmitter for CO-OFDM
Optical spectral efficiency for CO-OFDM
Channel model for CO-OFDM
The channel model describes the behavior of communications systems, thus fundamentally determining the performance of the systems
Deterministic MIMO Channel Capacity
• CSI is Known to the Transmitter Side
• CSI is Not Available at the Transmitter Side
Channel Capacity of Random MIMO Channels
Overview about MIMO
Contents:
Diversity Definition
Why Diversity
Types of Diversity
Types of combining
MIMO Definition
Why MIMO ?
MIMO Advantages and disadvantages
Applications of MIMO
Performance Analysis of Massive MIMO Downlink System with Imperfect Channel S...IJRES Journal
We investigate the ergodic sum rate and required transmit power of a single-cell massive
multiple-input multiple-output (MIMO) downlink system. The system considered in this paper is based on two
linear beamforming schemes, that is, maximum ratio transmission (MRT) beamforming and zero-forcing (ZF)
beamforming. What’s more, we use minimum mean square error (MMSE) channel estimation to get imperfect
channel state information (CSI). Compared with the perfect CSI case, both theoretical analysis and simulation
results show that the system performance is different when the imperfect CSI is taken into account.
MIMO radar is introduced in presentation ,its advantage .future scope,research area.
MIMO radars represent a new generation of radars. In contrast to the traditional phased-array radar in which the transmit elements can transmit only the scaled versions of same signal, a MIMO radar allows the transmitters to transmit multiple signals. This waveform diversity offers enhanced flexibility in transmit beampattern synthesis which is an important area of MIMO radar signal processing
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM )BhaSkar Nath
Principle of orthogonal frequency-division multiplexing (OFDM)
Optical transmitter for CO-OFDM
Optical spectral efficiency for CO-OFDM
Channel model for CO-OFDM
The channel model describes the behavior of communications systems, thus fundamentally determining the performance of the systems
Deterministic MIMO Channel Capacity
• CSI is Known to the Transmitter Side
• CSI is Not Available at the Transmitter Side
Channel Capacity of Random MIMO Channels
Overview about MIMO
Contents:
Diversity Definition
Why Diversity
Types of Diversity
Types of combining
MIMO Definition
Why MIMO ?
MIMO Advantages and disadvantages
Applications of MIMO
Electromyography Analysis for Person IdentificationCSCJournals
Physiological descriptions of the electromyography signal and other literature say that when we make a motion, the motor neurons of respective muscle get activated and all the innervated motor units in that zone produce motor unit action potential. These motor unit action potentials travel through the muscle fibers with conduction velocity and superimposed signal gets recorded at the electrode site. Here we have taken an analogy from the speech production system model as the excitation signal travels through vocal tract to produce speech; similarly, an impulse train of firing rate frequency goes through the system with impulse response of motor unit action potentials and travels along the muscle fiber of that person. As the vocal tract contains the speaker information, we can also separate the muscle fiber pattern part and motor unit discharge pattern through proper selection of features and its classification to identify the respective person. Cepstral and non uniform filter bank features models the variation in the spectrum of the signals. Vector quantization and Gaussian mixture model are the two techniques of pattern matching have been applied.
Optical fiber communication Part 2 Sources and DetectorsMadhumita Tamhane
For optical fiber communication, major light sources are hetero-junction-structured semiconductor laser diode and light emitting diodes. Heterojunction consists of two adjoining semiconductor materials with different bandgap energies. They have adequate power for wide range of applications. Detectors used are PiN diode and Avalanche Photodiode. Being very small in size and feeding to small core optical fiber, it is very important to study emission characteristics of sources and their coupling to fiber. As it can operate for low power over a long distance, received power is very small, hence study of noise characteristics of detectors is very essential...
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
Abstract: MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) . Keywords— Adaptive modulation ASTC code, Capacity, BER, Ergodic capacity, PAPR, Spectral Efficiency and SNR
Comparative Analysis of Distortive and Non-Distortive Techniques for PAPR Red...IDES Editor
OFDM is a popular and widely accepted modulation
and multiplexing technique in the area of wireless
communication. IEEE 802.15, a wireless specification defined
for WPAN is an emerging wireless technology for short range
multimedia applications. Two general categories of 802.15
are the low rate 802.15.4 (ZigBee) and high rate 802.15.3
(UWB). In their physical (PHY) layer design, OFDM is a
competing technique due to the various advantages it renders
in the practical wireless media. OFDM has been a popular
technique for many years and adopted as the core technique
in a number of wireless standards. It makes the system more
immune to interference like InterSymbol Interference (ISI)
and InterCarrier Interference (ICI) and dispersive effects of
the channel. It is also a spectrally efficient scheme since the
spectra of the signal are overlapping in nature. Despite these
advantages OFDM suffers from a serious problem of high
Peak to Average Power. This limits the system’s capabilities
and increases the complexity. This paper compares the signal
distortion technique of Amplitude Clipping and the
distortionless technique of SLM for Peak to Average Power
reduction
Blind Estimation of Carrier Frequency Offset in Multicarrier Communication Sy...IDES Editor
Orthogonal Frequency Division Multiplexing
(OFDM) systems are very sensitive to carrier frequency offset
(CFO), caused by either frequency differences between
transmitter and receiver local oscillators or by frequency
selective channels. The CFO disturbs the orthogonality among
subcarriers of OFDM system and results intercarrier
interference (ICI), which degrades the bit error rate (BER)
performance of the system. This paper presents a new blind
CFO estimation scheme for single-input single-output (SISO)
OFDM systems. The presented scheme is based on the
assumption that the channel frequency response changes
slowly in frequency domain. In this scheme an excellent tradeoff
between complexity and performance, as compared to
existing estimation schemes, is obtained. The improved
performance of the present scheme is confirmed through
extensive simulations.
BER Performance of MU-MIMO System using Dirty Paper CodingIJEEE
In this paper Dirty Paper Coding for communication system is implemented. MIMO application that involves devices such as cell phones, pocket PCs require closely spaced antenna, which suffers from mutual coupling among antennas and high spatial correlation for signals. DPC is used for compensating the degradation due to correlation and mutual coupling.
In this paper, we analyzed a numerical evaluation of the performance of MIMO radio systems in the LTE network environment. Downlink physical layer of the OFDM-MIMO based radio interface is considered for system model and a theoretical analysis of the bit error rate of the two space-time codes (SFBC 2×1 and FSTD 4×2 codes are adopted by the LTE norm as a function of the signal to noise ratio. Analytical expressions are given for transmission over a Rayleigh channel without spatial correlation which is then compared with Monte-Carlo simulations. Further evaluated channel capacity and simulation results show throughput almost reaches to the capacity limit.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
FPGA Design & Simulation Modeling of Baseband Data Transmission SystemIOSR Journals
Abstract: This paper describes a study on a baseband data transmission system developed for undergraduate
students studying communication engineering. Theoretical material, developed in the lectures, is briefly
covered. A practical system is presented with pre-detection filtering being employed to improve the bit error
rate. A simulation of the complete system is carried out on a Sun work station using the MATLAB simulation
package. Simulation and theoretical results are compared.
To meet the demands of high speed required by mobile communication of past generations ,one solution is to increase the number of antennas to the show and the reception of the wireless link this is called MIMO (Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same PCB is delicate because of the small volume that require some applications and electromagnetic antenna between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance frequency folling each with 20MHz offset this device is characterized by its original form that keeps is highly isolated antennas from the point of view electromagnetic coupling
DESIGN AND OPTIMIZATION A CIRCULAR SHAPE NETWORK ANTENNA MICRO STRIP FOR SOME...ijcseit
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
To meet the demands of high speed required by mobile communication of past generations ,one solution is
to increase the number of antennas to the show and the reception of the wireless link this is called MIMO
(Multiple input ,Multiple output )technology .however ,the integration of multiple antennas on the same
PCB is delicate because of the small volume that require some applications and electromagnetic antenna
between the coupling ,phenomena that we cannot neglect them .indeed a strong isolation between them has
been reached to reduce fading of the signal caused by the electromagnetic antenna reached to reduce
fading of the signal caused by the electromagnetic coupling and maximize the overall gain .in this article
we are interested then integration on the same printed circuit of eight antennas MIMO are not operation in
the same frequency band .the first antenna of this last work at 2.4GHz .other antennas have resonance
frequency folling each with 20MHz offset this device is characterized by its original form that keeps is
highly isolated antennas from the point of view electromagnetic coupling
Multi carrier equalization by restoration of redundanc y (merry) for adaptive...IJNSA Journal
This paper proposes a new blind adaptive channel shortening approach for multi-carrier systems. The
performance of the discrete Fourier transform-DMT (DFT-DMT) system is investigated with the proposed
DST-DMT system over the standard carrier serving area (CSA) loop1. Enhanced bit rates demonstrated
and less complexity also involved by the simulation of the DST-DMT system.
Design and Fabrication of a Two Axis Parabolic Solar Dish CollectorIJERA Editor
The work consists of the design of the chain drive system and the fabrication of the two axis parabolic solar dish.
It is a model study of the two axis parabolic dish which worked by the automatic circuit that was developed. Ready
made parabolic solar dish is taken and fabricated. The circular iron ring provides the two axis motion of the dish.
A compound chain drive system was developed for the smooth movement of the dish. An electromechanical
system which tracks the sun on both axes and which is controlled via a programmable logic control (PLC) was
designed and implemented. In this a theoretical study was done. A C program was made which gave the required
result for the graphical representation of the recorded radiation. Programmable Logic Controls (PLC) was used
instead of photo sensors, which are widely used for tracking the sun. The azimuthal angle of the sun from sunrise
to sunset times was calculated for each day of the year at 23.59 Lat & 72.38Longitude in the Northern hemisphere,
the location of the city Mehsana. According to this azimuth angle, the required analog signal was taken from the
PLC analog module and sent to the power window motor, which controlled the position of the panel to ensure that
the rays fall vertically on the panel. After the mechanical control of the system was started, the performance
measurements of the solar panel were carried out. The values obtained from the measurements were compared and
the necessary evaluations were conducted.
Bit Error Rate Performance of MIMO Spatial Multiplexing with MPSK Modulation ...ijsrd.com
Wireless communication is one of the most effective areas of technology development of our time. Wireless communications today covers a very wide array of applications. In this, we study the performance of general MIMO system, the general V-BLAST architecture with MPSK Modulation in Rayleigh fading channels. Based on bit error rate, we show the performance of the 2x2 schemes with MPSK Modulation in noisy environment. We also show the bit error rate performance of 2x2, 3x3, 4x4 systems with BPSK modulation. We see that the bit error rate performance of 2x2 systems with QPSK modulation gives us the best performance among other schemes analysed here.
Effective capacity in cognitive radio broadcast channelsMarwan Hammouda
Abstract—In this paper, we investigate effective capacity by
modeling a cognitive radio broadcast channel with one secondary transmitter (ST) and two secondary receivers (SRs) under quality-of-service constraints and interference power limitations.We initially describe three different ooperative channel sensing strategies with different ard-decision combining algorithms at the ST, namely OR, Majority, and AND rules. Since the channel sensing occurs with possible errors, we consider a combined
interference power constraint by which the transmission power of the secondary users (SUs) is bounded when the channel is sensed as both busy and idle. Furthermore, regarding the channel sensing decision and its correctness, there exist ...
Even tho Pi network is not listed on any exchange yet.
Buying/Selling or investing in pi network coins is highly possible through the help of vendors. You can buy from vendors[ buy directly from the pi network miners and resell it]. I will leave the telegram contact of my personal vendor.
@Pi_vendor_247
Poonawalla Fincorp and IndusInd Bank Introduce New Co-Branded Credit Cardnickysharmasucks
The unveiling of the IndusInd Bank Poonawalla Fincorp eLITE RuPay Platinum Credit Card marks a notable milestone in the Indian financial landscape, showcasing a successful partnership between two leading institutions, Poonawalla Fincorp and IndusInd Bank. This co-branded credit card not only offers users a plethora of benefits but also reflects a commitment to innovation and adaptation. With a focus on providing value-driven and customer-centric solutions, this launch represents more than just a new product—it signifies a step towards redefining the banking experience for millions. Promising convenience, rewards, and a touch of luxury in everyday financial transactions, this collaboration aims to cater to the evolving needs of customers and set new standards in the industry.
Falcon stands out as a top-tier P2P Invoice Discounting platform in India, bridging esteemed blue-chip companies and eager investors. Our goal is to transform the investment landscape in India by establishing a comprehensive destination for borrowers and investors with diverse profiles and needs, all while minimizing risk. What sets Falcon apart is the elimination of intermediaries such as commercial banks and depository institutions, allowing investors to enjoy higher yields.
What price will pi network be listed on exchangesDOT TECH
The rate at which pi will be listed is practically unknown. But due to speculations surrounding it the predicted rate is tends to be from 30$ — 50$.
So if you are interested in selling your pi network coins at a high rate tho. Or you can't wait till the mainnet launch in 2026. You can easily trade your pi coins with a merchant.
A merchant is someone who buys pi coins from miners and resell them to Investors looking forward to hold massive quantities till mainnet launch.
I will leave the telegram contact of my personal pi vendor to trade with.
@Pi_vendor_247
US Economic Outlook - Being Decided - M Capital Group August 2021.pdfpchutichetpong
The U.S. economy is continuing its impressive recovery from the COVID-19 pandemic and not slowing down despite re-occurring bumps. The U.S. savings rate reached its highest ever recorded level at 34% in April 2020 and Americans seem ready to spend. The sectors that had been hurt the most by the pandemic specifically reduced consumer spending, like retail, leisure, hospitality, and travel, are now experiencing massive growth in revenue and job openings.
Could this growth lead to a “Roaring Twenties”? As quickly as the U.S. economy contracted, experiencing a 9.1% drop in economic output relative to the business cycle in Q2 2020, the largest in recorded history, it has rebounded beyond expectations. This surprising growth seems to be fueled by the U.S. government’s aggressive fiscal and monetary policies, and an increase in consumer spending as mobility restrictions are lifted. Unemployment rates between June 2020 and June 2021 decreased by 5.2%, while the demand for labor is increasing, coupled with increasing wages to incentivize Americans to rejoin the labor force. Schools and businesses are expected to fully reopen soon. In parallel, vaccination rates across the country and the world continue to rise, with full vaccination rates of 50% and 14.8% respectively.
However, it is not completely smooth sailing from here. According to M Capital Group, the main risks that threaten the continued growth of the U.S. economy are inflation, unsettled trade relations, and another wave of Covid-19 mutations that could shut down the world again. Have we learned from the past year of COVID-19 and adapted our economy accordingly?
“In order for the U.S. economy to continue growing, whether there is another wave or not, the U.S. needs to focus on diversifying supply chains, supporting business investment, and maintaining consumer spending,” says Grace Feeley, a research analyst at M Capital Group.
While the economic indicators are positive, the risks are coming closer to manifesting and threatening such growth. The new variants spreading throughout the world, Delta, Lambda, and Gamma, are vaccine-resistant and muddy the predictions made about the economy and health of the country. These variants bring back the feeling of uncertainty that has wreaked havoc not only on the stock market but the mindset of people around the world. MCG provides unique insight on how to mitigate these risks to possibly ensure a bright economic future.
where can I find a legit pi merchant onlineDOT TECH
Yes. This is very easy what you need is a recommendation from someone who has successfully traded pi coins before with a merchant.
Who is a pi merchant?
A pi merchant is someone who buys pi network coins and resell them to Investors looking forward to hold thousands of pi coins before the open mainnet.
I will leave the telegram contact of my personal pi merchant to trade with
@Pi_vendor_247
How to get verified on Coinbase Account?_.docxBuy bitget
t's important to note that buying verified Coinbase accounts is not recommended and may violate Coinbase's terms of service. Instead of searching to "buy verified Coinbase accounts," follow the proper steps to verify your own account to ensure compliance and security.
how to sell pi coins in all Africa Countries.DOT TECH
Yes. You can sell your pi network for other cryptocurrencies like Bitcoin, usdt , Ethereum and other currencies And this is done easily with the help from a pi merchant.
What is a pi merchant ?
Since pi is not launched yet in any exchange. The only way you can sell right now is through merchants.
A verified Pi merchant is someone who buys pi network coins from miners and resell them to investors looking forward to hold massive quantities of pi coins before mainnet launch in 2026.
I will leave the telegram contact of my personal pi merchant to trade with.
@Pi_vendor_247
what is the future of Pi Network currency.DOT TECH
The future of the Pi cryptocurrency is uncertain, and its success will depend on several factors. Pi is a relatively new cryptocurrency that aims to be user-friendly and accessible to a wide audience. Here are a few key considerations for its future:
Message: @Pi_vendor_247 on telegram if u want to sell PI COINS.
1. Mainnet Launch: As of my last knowledge update in January 2022, Pi was still in the testnet phase. Its success will depend on a successful transition to a mainnet, where actual transactions can take place.
2. User Adoption: Pi's success will be closely tied to user adoption. The more users who join the network and actively participate, the stronger the ecosystem can become.
3. Utility and Use Cases: For a cryptocurrency to thrive, it must offer utility and practical use cases. The Pi team has talked about various applications, including peer-to-peer transactions, smart contracts, and more. The development and implementation of these features will be essential.
4. Regulatory Environment: The regulatory environment for cryptocurrencies is evolving globally. How Pi navigates and complies with regulations in various jurisdictions will significantly impact its future.
5. Technology Development: The Pi network must continue to develop and improve its technology, security, and scalability to compete with established cryptocurrencies.
6. Community Engagement: The Pi community plays a critical role in its future. Engaged users can help build trust and grow the network.
7. Monetization and Sustainability: The Pi team's monetization strategy, such as fees, partnerships, or other revenue sources, will affect its long-term sustainability.
It's essential to approach Pi or any new cryptocurrency with caution and conduct due diligence. Cryptocurrency investments involve risks, and potential rewards can be uncertain. The success and future of Pi will depend on the collective efforts of its team, community, and the broader cryptocurrency market dynamics. It's advisable to stay updated on Pi's development and follow any updates from the official Pi Network website or announcements from the team.
The secret way to sell pi coins effortlessly.DOT TECH
Well as we all know pi isn't launched yet. But you can still sell your pi coins effortlessly because some whales in China are interested in holding massive pi coins. And they are willing to pay good money for it. If you are interested in selling I will leave a contact for you. Just telegram this number below. I sold about 3000 pi coins to him and he paid me immediately.
Telegram: @Pi_vendor_247
how to sell pi coins at high rate quickly.DOT TECH
Where can I sell my pi coins at a high rate.
Pi is not launched yet on any exchange. But one can easily sell his or her pi coins to investors who want to hold pi till mainnet launch.
This means crypto whales want to hold pi. And you can get a good rate for selling pi to them. I will leave the telegram contact of my personal pi vendor below.
A vendor is someone who buys from a miner and resell it to a holder or crypto whale.
Here is the telegram contact of my vendor:
@Pi_vendor_247
how to swap pi coins to foreign currency withdrawable.DOT TECH
As of my last update, Pi is still in the testing phase and is not tradable on any exchanges.
However, Pi Network has announced plans to launch its Testnet and Mainnet in the future, which may include listing Pi on exchanges.
The current method for selling pi coins involves exchanging them with a pi vendor who purchases pi coins for investment reasons.
If you want to sell your pi coins, reach out to a pi vendor and sell them to anyone looking to sell pi coins from any country around the globe.
Below is the contact information for my personal pi vendor.
Telegram: @Pi_vendor_247
2. NOC 2011 IT - 1
path gain between LED and PD i for the k th path given
∞
¯ (k)
by hi =
(k)
hi (t) dt. The notation n(t) indicates an Nr
−∞
dimensional noise vector. The noise is the sum of the receiver
thermal noise and shot noise due to ambient light which
can be modeled as independent and identically distributed
additive white Gaussian noise (AWGN) with double sided
power spectral density σ 2 [2, eqn.(21)]. For the analysis in
this paper, H(t) is an Nr × Nt × (K + 1) normalized indoor
optical MIMO channel tensor, defined as
Fig. 1: OSM communication system model. The LED mapper ⎡ ⎤
maps input bits to LED indices. Each sequence of log2 (Nt ) h11 (t) h12 (t) · · · h1Nt (t)
⎢ h21 (t) h22 (t) · · · h2Nt (t) ⎥
input bits correspond to a certain LED index. ⎢ ⎥
H (t) = ⎢ . . .. . ⎥ (3)
⎣ .
. .
. . .
. ⎦
II. OSM S YSTEM M ODEL hNr 1 (t) hNr 2 (t) · · · hNr Nt (t)
The system model of the OSM approach is depicted in
The channel paths are obtained numerically via ray tracing
Fig. 1. A MIMO system consisting of Nt transmit units (in
technique as discussed in details in [9, eqn.(13)].
particular, light emitting diodes (LEDs)) and Nr receive units
(in particular, photo diodes (PDs)) is illustrated. The bits At the receiver, the PD converts the optical signal to
electrical signal and applies the optimal SM detector [10] to
to be transmitted at each time instance, q(t), are grouped
detect the active transmit unit as follows,
as the row vectors of the matrix x(t). For illustration pur-
poses, the bits to be transmitted in three time instances are ˜ = s ¯
arg max py y|¯, H
q (t) = 1 0 0 1 1 1 . Assuming Nt = 4, each √
log2 (Nt ) bits are transmitted at one time instance and grouped = arg min ρ h s 2 − 2 yT h s , (4)
T
as follows, x (t) = 10 01 11 , where (·)T T
{t=1} {t=2} {t=3} K K K
denotes the transpose. The bits in this matrix are mapped to where h = ¯ (k)
h1 ¯ (k)
h2 ··· ¯ (k)
hN r is an
one of the transmitting LEDs. The selected LED ( ) transmits k=0 k=0 k=0
Nr dimensional vector containing the sum of the channel
a non-return to zero (NRZ) pulse with an optical power path gains from transmit unit to each receive unit, H = ¯
(intensity) s = Pt at a particular time instance while all other h1 h2 · · · hNt is the channel matrix after the optical
LEDs are off. The intensity level carries no information and to electrical conversion at the receiver, ¯ is the transmitted
s
can be utilized to optimize power consumption and range. In column vector from the matrix s(t) at this time instance, and
the considered example, assuming the mapping table in Fig. 1,
√ ¯ 2
the resultant matrix is given by, s ¯
py y|¯, H = π −Nt exp − y − ρH¯ F s (5)
⎡ ⎤
0 0 0
is the probability density function (pdf) of y conditioned on
⎢ 0 s 0 ⎥ ¯
⎢ ⎥ the transmitted vector ¯ and the channel H. The notation · F
s
s(t) = ⎢ 0 0 s ⎥. (1)
⎣ ⎦ stands for the Frobenius norm of a vector or a matrix.
s 0 0 The estimated transmit unit index ˜ is then used to decode
{t=1} {t=2} {t=3}
the original information bits by inverse mapping process using
Each column of the matrix s(t) is transmitted at a single the same mapping table as used at the transmitter.
time instance where each element in the column vector corre-
sponds to the respective transmit unit. As can be seen, at any III. P ERFORMANCE A NALYSIS
give time only one transmit unit is active, all others transmit For Monte Carlo simulations, the considered 4x4 MIMO
zero power. The transmission is made over the optical MIMO system inside a room is depicted in Fig. 2(a). The height of
channel H(t). the transmit units from the ground is given by z in meters and
The received signal can be written as, the transmitters half power angle is given by φ 1 in degrees.
√ 2
The transmit units are placed on the ceilings with the exact
y(t) = ρH(t) ⊗ s(t) + n(t) (2)
locations shown in Fig. 2(b) and Fig. 2(c) for the unaligned
¯
r2 P 2
where ⊗ denotes time convolution, ρ = σ2r is the aver- and the aligned scenarios, respectively. The receive units are
age electrical SNR at each PD, r is the PD responsivity, placed on a desktop with height 1 m from the floor. The exact
Nr
¯ 1 (i) locations are shown in Fig. 2(b) and Fig. 2(c) for the unaligned
Pr = Nr Pr is the average received optical power at each
i=1 and the aligned scenarios, respectively.
K For the unaligned scenario, the transmit units are directed
PD with Pr
(i)
= ¯ (k)
hi Pt being the average received optical
k=0 toward the floor and the receive units are directed toward the
power at PD i when LED is active, K is the number of the ceiling. The receivers FOV is 90◦ . In Fig. 3, the average
¯ (k)
considered channel reflection paths, and hi is the channel BER is plotted versus the average electrical SNR at each
2
3. NOC 2011 IT - 1
0
10 0
10
−1 −1
10 10
−2 −2
10 10
BER
BER
−3 −3
10 10
−4 −4
10 10
φ1/2 = 35◦ simulation
z = 5m simulation
φ1/2 = 35◦ analytical z = 5m analytical
Fig. 2: (a) A 4x4 optical MIMO model inside a room. (b) Tx-
−5 −5
10 10
◦
φ1/2 = 40 analytical z = 6.5m analytical
φ1/2 = 60◦ analytical z = 8m analytical
Rx locations for the unaligned scenario. (c) Tx-Rx locations −6 −6
10 10
for the aligned scenario. Each Tx-Rx pair are directed toward 0 2 4 6
SNR (dB)
8 10 12 0 2 4 6
SNR (dB)
8 10 12
each other.
0
10 0
10
Fig. 4: Aligned OSM performance analysis.
−1
10 −1
10 1.00 at Rx1 1
Channel Impulse Response
0.55 at Rx2
1 0.53 at Rx3
Channel Impulse Response
0.55 at Rx4 0.8
−2
10 −2
10 0.8 LOS
First reflection
0.6
0.6
0.4
BER
BER
−3 −3
10 10
0.2
0.4
φ1/2 = 35◦ simulation z = 5m simulation
0
−4
10 φ1/2 = 35◦ analytical −4
10 z = 5m analytical 4
φ1/2 = 40◦ simulation z = 6.5m simulation 0.2
z = 6.5m analytical 2 Rx1 4
φ1/2 = 40◦ analytical
z = 8m simulation
−5 −5
10 10 2
φ1/2 = 60◦ simulation Y[m] 0
z = 8m analytical 0 0 X[m] 0 10 20 30 40
φ1/2 = 60◦ analytical Time (nsec)
−6 −6
10 10
0 5 10 15 20 25 30 0 5 10 15 20 25 30
SNR (dB) SNR (dB)
Fig. 5: Channel impulse response for the aligned scenario
between Tx2 and Rx1.
Fig. 3: Unaligned OSM performance analysis. In the left
subfigure, φ 1 values of 35◦ , 40◦ , and 60◦ are considered at
2 Compared to the results in Fig. 3, the aligned OSM sys-
z = 6 m. In the right subfigure, transmit units are considered tem performance enhances by at least 14 dB in SNR. This
at heights z =5, 6.5, and 8 m for φ 1 = 30◦ .
2 enhancement is not due to lower path loss for the aligned
scenario since the SNR is the same for all compared systems.
receiver. The results for at least 106 channel realizations are The improvement is rather due to de-correlating the MIMO
considered. Analytical and simulation results are presented for channel matrix by direct alignment of the transmit and receive
Nt = Nr = 4, z = 6 m for different values of φ 1 , and for
2
units. Further reduction in the FOV creates a diagonal channel
φ 1 = 30◦ for different values of z. The analytical results are
2
matrix and further enhances the performance.
upper bounds and calculated as discussed in [1, Section III, For the aligned scenario as in Fig. 2(c), the channel impulse
eqns. (5) and (6)]. The analytical BER equation is also shown response (LOS) when a single transmitter Tx2 is on and is
in Table I, where N (κ, ν) is the number of bit errors when aligned to the location of Rx1 is shown in the left-subplot of
choosing κ instead of ν as transmit unit index. Fig. 5 (φ 1 is 60◦ , FOV is 45◦ , z = 6 m). Rx1 is aligned to
2
The performance of the unaligned system is poor and for the location of Tx2 and the other receive units are directed
all considered φ 1 angles, see the left sub-plot in Fig. 3,
2
toward the ceiling. The de-correlation is clearly noticed from
SNR values above 20 dB are required to achieve 10−2 BER. the obtained amplitudes at the different locations of the four
According to the right sub-plot in Fig. 3, at 20 dB SNR, a transmit units. For the same aligned scenario, the channel
BER ≤ 10−3 can not be achieved regardless of the considered impulse response (LOS and first reflection path) between Tx2
height, z. and Rx1 is shown in the right-subplot of Fig. 5. It can be
The performance can be significantly enhanced by aligning found that the 3 dB bandwidth for this path is 30 MHz and
the transmit and receive units as depicted in Fig. 2(c) and that the channel delay spread is approximately 33 ns. At this
reducing the receivers FOV to 45◦ . Performance results for delay spread, 96% from the overall power is captured.
this scenario are shown in Fig. 4. It can be observed that The SNR distributions on a horizontal plan at 1 m from
neither changing the angles, nor changing the heights affect the floor for the unaligned and the aligned scenarios (a single
the simulated BER performance. However, slight differences transmit unit, Tx2, is turned on and an AWGN model intro-
are noticeable between analytical and simulation results which duced in [2, eqn.(21)] is considered) are shown in Fig. 6(a) and
can be attributed to numerical errors caused by the small Fig. 6(b), respectively. For the unaligned scenario, it can be
variation between the channel path gains with different heights seen that the maximum achieved SNR is 11 dB. The achieved
and angles. maximum SNR would not allow a useful BER as can be found
3
4. NOC 2011 IT - 1
TABLE I: OSM, OOK, PPM, and PAM performance
Scheme BER Data rate
√
OOK Q ρ B
L Llog2 L log2 L
L-PPM 2
Q 2
ρ L
B
2(L−1) log 2 L
L-PAM Llog2 L
Q (L−1)2
ρ Blog2 L
Nt Nt
1 ρ 2
OSM Nt
N (κ, ν)Q 4
hk − hν Blog2 Nt
κ=1 ν=1
ν=κ
(a) (b)
IV. C ONCLUSIONS
Fig. 6: SNR distribution. A single transmitter Tx2 is on (15 W OSM performance can significantly be enhanced by a proper
optical power), φ 1 is 60◦ , and the receiver is directed toward
2 alignment of transmit and receive units. The resultant scheme
the ceiling. (a) unaligned scenario. Tx2 directed toward the is shown to be very efficient in terms of power and band-
floor and FOV is 90◦ . (b) aligned scenario. Tx2 is aligned to width efficiency as compared to the existing OW modulation
the location of Rx1 and FOV is 45◦ . techniques. The simplicity of the scheme makes it a strong
candidate for practical implementations. The considered OSM
−1
10
4−PPM, 10 Mbps
OSM, 40 Mbps
system is shown to achieve a BER slightly better than OOK
OOK, 20 Mbps
−2
4−PAM, 40 Mbps and a data rate that is twice that of OOK. The power efficiency
10
of OSM is expected to be significantly enhanced by increasing
−3
the number of receive units and/or considering channel coding
BER
10
−4
10 techniques. In addition, the bandwidth efficiency of OSM
−5
can be boosted by increasing the number of transmit units.
10
These will be addressed in detail in future publications and in
−6
10
0 5 10
SNR (dB)
15 20 experimental demonstrations.
Fig. 7: Performance comparison between aligned OSM, OOK, R EFERENCES
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values between 7.5 dB and 8.5 dB are achieved in several Proceedings of the IEEE, vol. 85, no. 2, pp. 265–298, Feb. 1997.
locations. These SNRs are sufficient to achieve at least 10−3 [3] B. Wilson and Z. Ghassemlooy, “Pulse Time Modulation Techniques for
Optical Communications: A Review,” in In the Proceeding of the IEE
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Finally, the performance of the aligned OSM (φ 1 is 60◦ ,
2
[4] BROADCOM Corporation, “802.11n: Next-Generation
Wireless LAN Technology,” White paper, BROADCOM
FOV is 45◦ , z = 6 m) system is compared to the performances Corporation, Tech. Rep., Apr. 2006, retrieved Aug. 4, 2006
of OOK, 4-PPM, and 4-PAM [2, 11] as shown in Fig. 7. Also, http://www.broadcom.com/docs/WLAN/802-11n-WP100-R.pdf.
the BER equations as a function of the SNR (ρ) and the data [5] L. Zeng, D. O’Brien, H. Minh, G. Faulkner, K. Lee, D. Jung, Y. Oh, and
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techniques are listed in Table I; where Q(·) denotes the Q- Select. Areas Commun., vol. 27, no. 9, pp. 1654–1662, Dec. 2009.
function. In OSM, a NRZ pulse is transmitted at each time [6] P. Djahani and J. M. Kahn, “Analysis of Infrared Wireless Links
Employing Multibeam Transmitters and Imaging Diversity Receivers,”
instance from a single transmit unit. Hence, for the same SNR, IEEE Transactions on Communications, vol. 48, no. 12, pp. 2077–2088,
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(OMIMO),” in Proc. IEEE Global Telecommunications Conference
The PPM technique is the best technique in terms of power GLOBECOM ’04, vol. 2, Texas, USA, 29 Nov.–3 Dec. 2004, pp. 928–
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[8] R. Mesleh, H. Haas, S. Sinanovi´ , C. W. Ahn, and S. Yun, “Spatial
c
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of Multipath Impulse Response for Indoor Wireless Optical Channels,”
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4