A Generalized Bit Error Rate Evaluation for Index Modulation Based OFDM System (original) (raw)
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International Journal of Computer Applications, 2014
In this paper we investigate the bit error rate performance of orthogonal frequency division multiplexing system with channel estimation through least square error (LSE) and minimum mean square error (MMSE) algorithms. In this paper we are implementing the M-ary phase shift keying (M-PSK) and M-ary quadrature amplitude modulation (M-QAM) digital modulation techniques for mapping the signal in OFDM system for bit error rate evaluation with the employment of comb-type pilot symbol-assisted channel estimation algorithm over frequency selective multi-path Rayleigh fading channel. Here the performance of Least Squares method depends on not only on the signal-to-noise ratio (SNR) but also on the pilot ratio. Simulation results show that applying the LSE and MMSE channel estimation algorithm, they produce the best BER performance over the fading channel. We can consider the OFDM system as either a modulation technique or a multiplexing technique. In a single carrier system, a single fade or interferer can cause the entire link to fail, but in a multicarrier system, only a small percentage of the subcarriers will be affected [1]. Here we are using the pilot symbols as a guard band to eliminate the Inter Symbol Interference, and cyclic prefix eliminates the Inter Subcarrier Interference.
International Journal of Mobile Network Communications & Telematics, 2014
Today, we have required to accommodate a large number of users under a single base station. This can be possible only if we have some flexibility over the spectrum. Previously we have lots of multiplexing methods to accommodate large number of signals in time and frequency domain. But now we have required to accommodate a large number of users in the same bandwidth, without any fading over the received signal. So, orthogonality can be maintained over the frequency response. This technology is now more popular in the mobile communication domain, called Orthogonal Frequency Division Multiplexing (OFDM). Actually user data can be converted into the parallel form and then they are modulated using digital modulation techniques. Finally, they have followed by OFDM Modulator and cyclic prefix can be inserted into the OFDM symbols. Here, I have worked on the measurement of Bit error rate for different modulation techniques in OFDM technology. It has been considered that subchannel size is not constant. According to that I have concluded the overall idea regarding the performance under OFDM technology.
Bit Error Rate Analysis of OFDM
Orthogonal Frequency Division Multiplexing or OFDM is a modulation format that is being used for many of the latest wireless and telecommunications standards. OFDM has been adopted in the Wi-Fi arena where the standards like 802.11a, 802.11n, 802.11ac and more. It has also been chosen for the cellular telecommunications standard LTE / LTE-A, and in addition to this it has been adopted by other standards such as WiMAX and many more. The paper focuses on The MATLAB simulation of Orthogonality of multiple input multiple output (MIMO) signals and bite error rate (BER) with MIMO transmitter and receiver.
The Orthogonal Frequency Division Multiplexing (OFDM) is a practical application of both amplitude and phase modulation scheme and has taking its place in Multiplexing Techniques where a number of independent message signal are at the same time transmitted over a single channel. OFDM is beneficial in transmission with high data rate and better performance. High data rates are achieved by the use of multiple carriers and performance improvement. This paper is based on the QPSK and QAM of Different Modulation order. The performance Evaluation is done using the Bit Error Rate (BER) Against the Signal to Noise Ratio (SNR) parameters which shows a low BER to High SNR. At the end of the work, it was found out that the QPSK has more better performance in OFDM system than the QAM. QPSK has lower BER than the QAM in AWGN, Rayleigh and Rician channel. The performance of QPSK in OFDM is better than the QAM in the OFDM system. The simulation was done using MATLAB/SIMULINK. 1. Introduction All electrical signals exist in continuous wave nature at a given time. Analog communication was the order of the day until recently, a digital form of communication has replaced it due to significant advantages over the analog means of communication. The most important features are the digital modulation techniques adopted by the digital communication systems. Some of the advantages of the techniques includes greater noise immunity and its robust channel impairment, easier multiplexing of various forms of information, accommodation of larger amount of digital error control codes with detection and correction transmission errors and implementation of digital modulation and demodulation scheme and techniques. The type of MODEM adopted depends largely on quality factors such as provision of low bit error rate at low received signal to noise ratio, good performance in an interference, multipath and fading environments, minimum bandwidth occupation and lastly easy and probably cost effective in implementation. This paper in based on BER and SNR analysis using the Digital Communication M-array Modulation Scheme such as PSK and QAM. The binary scheme of a digital data consists of only two symbols i.e. 1 and 0. The distinct waveform known as pulse is assign to these two symbols and transmitted over a channel and detected at the receiving end after converting it back to binary data. In an M-array scheme, a symbol consists of more than one binary digits of either 0 and 1 or both. OFDM as a transmission scheme is adopted by the broadband radio systems and its current used in a well-known standard IEEE 802.16 hence the part which determines the performance in a combination of the dynamic sub-carrier allocation, transmission power allotment, and adaptive modulation (Sivanagaruju & Siddiah, 2014). OFDM is beneficial in transmission with high data rate and better performance. High data rates are achieved by the use of multiple carriers and performance improvement caused by interference ISI which disports the expected signal (Mousumi et al. 2014). Other benefits include increase in spectral efficiency and also minimizes multipath distortion. In this paper, a total number of 128 subcarriers is used at a cyclic prefix of 32. The Maximum bit error is at 100 at 1e7 maximum number of errors. OFDM baseband signal is typically the sum of number of orthogonal sub-carriers, of which each subcarrier is modulated independently by its own data either QAM or PSK. As the name implies, simultaneous transmission is allowed without interference on a lot of sub-carrier from each other. The simplest form of PSK in the binary scheme BPSK. Though the QPSK will be used in this evaluation in detail. The BPSK like QAM overlap without interference other form of PSK is QPSK (Quadrature phase shift keying). QPSK is often used in the evaluation of the Bit Error rate (BER) due to its improved spectral efficiency requirement and for a given bit rate 1/T b, a QPSK system requires just half the bandwidth required for a BPSK system. Hence, QPSK is bandwidth efficient. The QPSK uses the points constellation diagram. QPSK encodes two bits per symbol. In this paper, QAM and PSK will be used in the analysis of the BER as they modulate both phase modulation and
A novel approach for performance evaluation of OFDM with error correction coding and interleaving
Gateway to 21st Century Communications Village. VTC 1999-Fall. IEEE VTS 50th Vehicular Technology Conference (Cat. No.99CH36324), 1999
In this paper, a comparably simple method for the performance analysis of error correction coding including interleaving is applied to orthogonal frequency division multiplexing (OFDM). ATM cell oriented data transmission is considered. The method, previously proposed for hybrid simulation schemes (simulation of channel realizations followed by analytical performance prediction for the generated channels), is extended to a completely analytical one. The resulting technique is capable of yielding average bit and frame error rates, as well as outage probabilities. Rayleigh fading channels are investigated. The distribution of the wide-band average power of the frequency-selective channel is derived.
MIMO-OFDM (Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing) system has been recognized as one of the most popular and competitive technique in a wireless environment nowadays. The performance is calculated in terms of Bit Error Rate (BER) versus the Signal to Noise Ratio (SNR). In this paper we discuss the BER performance of the MIMO-OFDM system with two different equalizers (ZF and MMSE) for various modulation techniques i.e. BPSK, QPSK, 16-QAM and 64-QAM using multipath fading channels i.e. AWGN (Additive White Gaussian Noise), Rayleigh and Rician channel. The multicarrier modulation is employed, which gives advantages like inter symbol interference (ISI) reduction, high data rate, higher reliability, and better performance in multipath fading. The simulation results show that, with MMSE and ZF equalizers, the BER performances is better in MMSE equalizer. Further we analyzed in different fading channels for various modulation techniques in both the equalizers.
Simulation and Bit Error Rate Performance Analysis of 4G OFDM Systems
2009
In this paper a simulation based system developed for analysis and Bit Error Rate (BER) performance measurement of Orthogonal Frequency Division Multiplexing (OFDM) systems. This paper involves the basics of OFDM system. In this paper bit error rate is calculated and measured with respect to Signal to Noise Ratio (SNR), Doppler Effect, and guard interval. BPSK, QPSK and 16PSK are used as modulation techniques. Additive White Gaussian Noise (AWGN) is used as a communication channel. The effect of SNR, Doppler Effect, and guard intervals on OFDM signals improves the system performance. Index Terms -AWGN, Bit Error Rate (BER), Doppler Effect, Guard interval, OFDM, Signal-to-Noise Ratio (SNR).
Bit Error Rate Performance of OFDM/OQPSK and CPM with Channel Coding Over AWGN Channel
2018
In this paper, Bit Error Rate performance of Orthogonal Frequency Division Multiplexing/Offset Quadrature Phase Shift Keying (OFDM/OQPSK) and Continuous Phase Modulation (CPM) over Additive White Gaussian Noise (AWGN) channel is presented. The Bit Error Rate (BER) performance for OFDM/OQPSK and CPM is compared in two separate simulations. The first without channel coding while the second with the block and convolutional coding scheme. The use of OFDM has proven to be effective as its sub carriers are orthogonal to each other providing the advantage of lesser inter-symbol interference. The simulation setup is such that signals are generated from a Bernoulli binary source where they undergo modulation by OFDM/OQPSK and CPM in separate simulations before entering the AWGN channel after which demodulation takes place. Outputs from the demodulator goes into the error rate calculator where charts showing the bit error rates are obtained. The simulation results showed a bit error rate of 1...
BIT ERROR RATE PERFORMANCE ENHANCEMENT OF ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING
ARPN Journal of Engineering and Applied Sciences, 2015
Orthogonal Frequency Division Multiplexing (OFDM) is a bandwidth efficient signaling scheme for wide band digital communications. A general problem found in high speed communication is Inter-Symbol Interference (ISI). ISI occurs when a transmission interferes with itself and the receiver cannot decode the transmission correctly. Orthogonal frequency division multiplex (OFDM) modulation is being used more and more in telecommunication, wired and wireless. DVB and DAB already use this modulation technique and ADSL is based on it. The advantages of this modulation are the reason for its increasing usage. OFDM can be implemented easily, it is spectrally efficient and can provide high data rates with sufficient robustness to channel imperfections. Multiple-input-multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) systems provide high spectral efficiency for wireless communication system. However, they have a major drawback of high peak to-average power ratio (PAPR) which results in inefficient use of a power amplifier.. Thus, many studies have sought to develop PAPR reduction methods. The purpose of this paper is to enhance the Bit Error Ratio (BER) of a transmission varies when Signal to Noise Ratio (S/N Ratio) is changed on transmission channel and also we reduced the peak average power ratio. Here we discussed commanding of OFDM signal in time domain to reduce PAPR and also we discussed how ISI is reduced. Keywords: bit error rate (BER), orthogonal frequency-division multiplexing (OFDM), energy efficient, inter symbol interference (ISI), multiple input-multiple-output (MIMO), signal to noise ratio(S/N ratio).