QPSK/QAM

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Comparative Analysis of DP QPSK and DP 16 QAM Optical Coherent Receiver, with Taking in View the Best Analyses of the Phase Noise in terms of Average BER using Digital Filters

Comparative Analysis of DP QPSK and DP 16 QAM Optical Coherent Receiver, with Taking in View the Best Analyses of the Phase Noise in terms of Average BER using Digital Filters

Comparative analysis of DP QPSK and DP 16-QAM has been done in terms of power spectrum. The DP 16-QAM giving the best result in terms of power spectrum with the transmitted power confined at the receiver end at the optical window i.e 1550 nm. Further Phase Noise of DP 16-QAM optical coherent receiver has been analyzed under the influence of different digital filters, i.e. Bessel, Butterworth, Chebyshev and Gaussian filters by varying filter order from one to six. During analysis, Gaussian Filter 3 rd order shows best result

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SCFDE System Using Linear Equalizers for MIMO SystemWith BPSK, QPSK and QAM

SCFDE System Using Linear Equalizers for MIMO SystemWith BPSK, QPSK and QAM

Fig 1 shows the Alamouti STBC scheme only for two transmit and receive antennas for BPSK modulation over the Raleigh channel. Transmit diversity scheme Alamouti shows theoretical and Simulink result.Fig 2 shows the Alamouti scheme for zero forcing equalizer with the rate 2, 4, and 6. Fig 3 shows Alamouti scheme with MMSE equalizer for the rate 3, 6, and 9. And the Fig 4 comparesAlamouti ZF and MMSE equalizers for the rate 3, 6, and 9. Fig 5 and Fig 6 shows outage probability of BPSK, QPSK and 16 QAM modulations for AlamoutiZF and MMSE equalizer with rate 3, 6, 9. Tabel 1 shows comparison between BPSK, QPSK, 16 QAM and Alamouti scheme with linear equalizers for rate 3, 6, 9. This can say ZF equalizer gives better performance for BPSK, QPSK, 16 QAM with the rates 3, 6, 9. Fig. 5 shows Alamouti scheme ZF equalizer for rates 3, 6, 9 gives better performance combine with 16 QAM modulation techniques. Tabel-1: Comparison of different modulation with
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SIGNAL TO NOISE RATIO ESTIMATION OF QAM AND QPSK MODULATION TECHNIQUE AT 910MHz and 2116 4 MHz USING MEASURED DATA

SIGNAL TO NOISE RATIO ESTIMATION OF QAM AND QPSK MODULATION TECHNIQUE AT 910MHz and 2116 4 MHz USING MEASURED DATA

Estimation of signal to noise ratio for the received signal is an important task in communication systems. The knowledge of the SNR is a requirement on many systems in order to perform efficient signal detection and link adaptation. In adaptive modulation system we need a way to decide which modulation level is best suited for the present channel condition, in this paper we decided to use the estimated SNR of the link as a channel metric to decide the switching levels. The channel estimation using two digital modulation technique (QAM and QPSK) are considered in W-CDMA environment, as we increase the range of communication, we step down to lower modulation (QPSK) but as we reduce the communication range means we are closer to the base station; we can utilize higher order modulation (QAM) for increase in throughput thus allowing the system to overcome multipath fading and other interferences. The results shows that the values of signal to noise ratio (SNR) from 10-12dB, the modulation scheme that yielded the desired BER of 10 -3 is QPSK modulation technique while SNR values greater than 18dB, QAM modulation technique can be used doubling the capacity compared with QPSK modulation technique.
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BER Analysis of Mobile WiMAX System Using STBC Code in MIMO System under AWGN and Other Channels

BER Analysis of Mobile WiMAX System Using STBC Code in MIMO System under AWGN and Other Channels

Hadj Zerrouki & Mohamed Feham in 2010[13] published that IEEE 802.16e -2004 currently supports several multiple- antenna options including Space-Time codes (STC) Multiple-Input Multiple-Output (MIMO) antenna systems and Adaptive Antenna Systems (AAS). In this extension to basic SISO mode a number of 2x2 MIMO extensions are analyzed under different combinations of digital modulation (QPSK,QAM) and convolution code with ½, 3/4 rated codes.The book “Fundamental of wireless communication” mainly includes the research on the basic aspects of wireless communication along with many techniques to discover the utility of its modern era. MIMO would be the most innovative approach in the modern wireless system to improve the capacity with the highest superior quality. [14].P.Samundiswary & Ravi Rajan Prasad published in 2013about the performance analysis of MIMO-Mobile WiMAX system using STBC using different channels. From this paper we get an idea of inclusion of MIMO in mobile WiMAX system provides a robust platform for Space, Time and Frequency selective fading conditions and increases both data rate and system performance.[10]
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The International Journal of Innovative Research in Science & Engineering (IJIRSE)

The International Journal of Innovative Research in Science & Engineering (IJIRSE)

This OFDM interconnected technique has been familiarized terminated 40 years ago. This technique has stayed chosen for various current and future communication systems all over the world in many applications. In this paper, we discussed the different modulation technique (BPSK, QPSK, QAM) which has been applied on OFDM system using AWGN channel. A simulation study is implemented using MATLAB Simulink tool to study the BER performance parameter on AWGN channel. It is observed that BPSK based OFDM system has

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Adaptive Modulation and Coding for Multi Hop Network

Adaptive Modulation and Coding for Multi Hop Network

Performance measure like packet delivery ratio, throughput, delay and number of packets dropped is carried out for four different modulations like BPSK, QPSK, 16-QAM and 64- QAM. By the result it is concluded as lower order modulation like BPSK gives better performance compared to higher order modulation. Adaptive Modulation schema is applied by considering packet drop time of each modulation and better throughput is obtained.

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Performance of IEEE 802.16e MIMO-OFDM System with  Alamouti Scheme.

Performance of IEEE 802.16e MIMO-OFDM System with Alamouti Scheme.

WiMAX is a wireless digital communications system,also known as IEEE 802.16 that is intended for wireless "Metropolitan Area Networks". WiMAX can provide broadband wireless access (BWA) up to 30 miles (48.2803 km) for fixed stations, and 3-10 miles (4.8-16.0 km) for mobile stations. In contrast, the Wi-Fi-802.11 wireless local area network standard is limited in most cases to only 100 - 300 feet (30.8 – 91.44 meter). It is also known as 802.16 networking or wireless networking. The new area of communication, currently employed in some parts of the world, is Worldwide Interoperability for Microwave Access (WIMAX). It is the latest technology which is approved by IEEE 802.16 group, which is a standard for point-to-multipoint wireless networking. The MIMO-OFDM is a key technology for next-generation cellular communications (Mobile WiMAX, IMT Advanced) as well as wireless Personal Area Network, wireless Local Area Network (IEEE 802.11a, IEEE 802.11n) and broadcasting (DAB, DVB). In this paper analysis of the multiple antenna technologies like SISO, MIMO system under different combination of modulation technologies like BPSK, QPSK, 8-QAM and 16-QAM with mobile wireless channel AWGN used and the results shows under the bit error rate versus signal to noise ratio .
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Adaptive Modulation Techniques for Duplex OFDM Transmission

Adaptive Modulation Techniques for Duplex OFDM Transmission

Adaptive modulation can reduce the BER to a level, where channel decoders can perform well. Fig. 12 shows both the un- coded and coded BER performance of a 512 subcarrier OFDM modem in the fading wideband channel of Fig. 3, assuming per- fect channel estimation. The channel coding employed in this set of experiments is a turbo codec [37] with a data block length of 1000 bits, employing a random interleaver and 8 decoder it- erations. Accordingly, interleaving and coding is applied to the entire OFDM symbol, rather than to the individual subbands. Combining the above turbo codec with adaptive modulation en- sures that the modem loads the subcarriers with bits according to the associated subcarrier quality and hence a fixed-rate turbo codec is adequate for the protection of the bits. The constituent half-rate convolutional encoders were of constraint length 3, with octally represented generator polynomials of (7, 5). It can be seen that the turbo decoder provides a considerable SNR gain for the different fixed modulation schemes, with a BER of 10 for SNR values of 13.8 dB, 17.3 dB, and 23.2 dB for BPSK, QPSK, and 16 QAM transmission, respectively.
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Comparison of LMS and FDAF Algorithms in Equalization of Fading Channel

Comparison of LMS and FDAF Algorithms in Equalization of Fading Channel

The paper is organized as follows. Section II gives the theoretical analysis of the adaptive equalizer and adaptive algorithm (LMS and FDAF), section III gives the results where constellation diagram of received symbols (16-QAM and QPSK) for the cases of with and without equalization, BER and a comparison of two algorithms are made. Finally section IV concludes the paper.

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Large-System Analysis of Correlated MIMO Multiple Access Channels with Arbitrary Signaling in the Presence of Interference

Large-System Analysis of Correlated MIMO Multiple Access Channels with Arbitrary Signaling in the Presence of Interference

The aforementioned studies regarding MIMO systems with co-channel interference have all concentrated on the special case, where Gaussian signals are transmitted both by the desired user and the interfering terminals. This is in contrast to real-world systems, where discrete constellations such as QPSK and QAM are used. These realistic cases are, however, out-of-bounds for random matrix theory, except for setups where sub-optimal linear detection and per-stream decoding is considered. To investigate the performance bounds of generic systems with non-Gaussian channel inputs, a tool borrowed from the field of statistical physics, namely the replica method, has been recently used.
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Maximum Likelihood Equalisation for STBC MIMO on Test Bed

Maximum Likelihood Equalisation for STBC MIMO on Test Bed

We have analyzed the bit error rate and symbol error rate performance of STBC-MIMO system with transmitter diversity for different modulation techniques e.g QPSK , 4-QAM,16- PSK and 16-QAM. The maximum likelihood estimation method with transmitter diversity is verified on hardware and simulated in MATLAB to arrive at the specifications. The design is synthesized and implemented on Test Bed. Thus, the real time estimation of channel is performed on Test Bed and BER and SER performance is evaluated using simulations in MATLAB.
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A Multiresolution Channel Decomposition for H 264/AVC Unequal Error Protection

A Multiresolution Channel Decomposition for H 264/AVC Unequal Error Protection

In the classical wavelet analysis the signal is coded us- ing a recomposition tree. The transmitter first splits the data sequence, filters each of the subsequences to create the resulting OFDM symbol. The OFDM sequences are then processed in a serial fashion for transmission. This approach leads to the time/frequency representation shown in Figure 7(b), where each block represents a single data symbol. Each of these blocks has the same area, but symbols mapped to higher frequencies have shorter time durations. The data rate is adapted to the carrier frequ- ency as symbols occupy different periods of their as- signed sub-carriers. One can map the coarse modulated symbol of the MR constellation to coarse coefficients carriers frequencies (i.e. QPSK base layer symbols car- rying high profile unit to more rugged carriers where the spectral efficiency is not a concern), and the fined modu- lated symbol of the MR constellation to fined coeffi- cients carriers (i.e. 16-QAM symbols to the fine carriers frequencies). Multiresolution OFDM wavelet do not need cyclic prefix for synchronization which leads to a better symbol rate.
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1.
													Design and measurement of ber of faded qpsk modulated system

1. Design and measurement of ber of faded qpsk modulated system

Modulation [3] is the process of changing the amplitude, frequency or phase of a radio frequency carrier signal (a carrier) to change with the information signal (such as voice or data). Four modulations are supported by the IEEE 802.16 standard: BPSK, QPSK, 16-QAM and 64-QAM. In this case the modulations used in the OFDM and OFDMA physical layers are introduced with a short description for each.

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High dimensionality carrierless amplitude phase modulation technique for radio over fiber system

High dimensionality carrierless amplitude phase modulation technique for radio over fiber system

Recently, higher order modulation formats are broadly studied for long haul optical communication systems. These high order modulation formats include quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), and orthogonal frequency division multiplexing (OFDM) with coherent detection and digital signaling processing (DSP) algorithm (Tao et al., 2013). For external modulation, IQ modulator is normally utilized at the transmitter, and optical hybrid and local oscillators together with DSP algorithms at the receiver. These sources are implemented by using application-specific integrated circuits (ASICs) for signal detection.
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WIMAX-802.16E MIMO (2×4 AND 2×8) SYSTEM WITH AWGN CHANNEL Pratik Bhiwapurkar1, Mukesh Patidar2, Shyam Gehlot3, Dr. Pragya Nema4

WIMAX-802.16E MIMO (2×4 AND 2×8) SYSTEM WITH AWGN CHANNEL Pratik Bhiwapurkar1, Mukesh Patidar2, Shyam Gehlot3, Dr. Pragya Nema4

In this analysis we are used in AWGN (Additive White Gaussian Noise) and different modulation schemes used like BPSK, QPSK, 8-QAM and 16-QAM. The performance of used New scheme Alamouti with combination of MIMO (multiple input and multiple output). The simulation results are shown in figure 3 and the result analysis are shown in table 1.

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A Dynamic Reconcile Algorithm for Address Generator in WiMAX Deinterleaver

A Dynamic Reconcile Algorithm for Address Generator in WiMAX Deinterleaver

WiMAX performs its operation based upon the IEEE standard specified in [1] which pronounces the code rates, interleaver depths within the specified modulation schemes. WiMAX can be regarded as a replacement for the existing last mile wired network, it can create an ad hoc communication network which can be deployed for disaster affected areas with ease [2]. Deinterleaver performs its operation based on the addresses which are generated from the address generator unit based upon the QPSK, 16-QAM or the 64-QAM modulation schemes respectively. Overall performance of deinterleaver depends upon the address generator unit’s performance, thus to enhance the performance of the deinterleaver unit the address generator has to optimized and made simpler and faster. In this paper a new algorithm for the address generator is been proposed based upon a correlation and the algorithm supports varying modulation schemes in the WiMAX deinterleaver, the algorithm has been found to more resource efficient in comparison to recent works [5], [9].
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Applications of Differential CDMA Schemes and Control Technology for Distribution Substations

Applications of Differential CDMA Schemes and Control Technology for Distribution Substations

This paper presents an approach to achieve monitoring and control of distribution systems in a distribution substation using power-line communication (PLC) combined with Hadamard code. Four different techniques, i.e., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 16-quadrature amplitude modulator (QAM) and 64-QAM in code division multiple access (CDMA), are employed. With spreading-spectrum modulation and demodulation in the studied PLC system, the proposed approach can achieve reliable high-speed information transmission through power lines. With Hadamard code, the signals corresponding to different relays are orthogonal to each other and the interference among them can be reduced. The proposed approach has the advantages of high-speed detection, bi-direction communication, reading and backup data, control and turn-off functions, displaying the real-time system information, etc. When 100 kHz is used as the carrier frequency for 256 relays under power-line noise below 14 dB, the simulation results show that the bit error rate (BER) is less than 10 -5 . The proposed scheme can be applied to the smart-grid distribution substation of the studied distribution systems.
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OFDM AS AN ACCESS TECHNIQUE FOR NEXT GENERATION NETWORK

OFDM AS AN ACCESS TECHNIQUE FOR NEXT GENERATION NETWORK

With the rapid growth of digital wireless communication in recent years, the need for high speed mobile data transmission has increased. New modulation and access techniques are being implemented to keep up with the desired more communication capacity. Processing power has increased to a point where OFDM has become feasible and economical in the next generation networks. Some examples of current applications using OFDM include DVB (Digital video broadcasting), DAB (Digital audio broadcasting), and HDTV (high - definition television).OFDM as a transmission technique has been known having a lot of strengths compared to any other transmission technique, such as its high spectral efficiency, its robustness to the channel fading. Orthogonal frequency division multiplexing (OFDM) has become very popular, allowing high speed wireless communications. In this paper, we have implemented the OFDM modulator and demodulator for the next generation network by using different types of digital modulation techniques such as BPSK, QPSK, 16- QAM and 64-QAM and comparing their BER and number of symbols required for each technique. MATLAB environment was used for simulation of proposed algorithm.
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BER Comparison of SC-FDMA and OFDM System Using Different Modulation Techniques

BER Comparison of SC-FDMA and OFDM System Using Different Modulation Techniques

impairments such as Doppler Shift due to user mobility and High-Power Amplifier (HPA) distortion when amplifying the transmitted OFDM symbol. It was shown that the resulting inter-carrier interference (ICI) generated by these impairments becomes very significant in OFDM system, and severely degrades its BER performance. In [3] author presented an efficient technique for the BER of OFDM system over Nakagami–m fading channels, using well known characteristics function based analysis approach. The average BER expressed in terms of the higher transcendental function such as the confluent hyper geometric functions. The numerical results showed that depending on the number of channel taps, the BER performance may degrade with increasing values of Nakagami–m fading parameters. In [4] author presented a work in which a guard interval (GI) was inserted using cyclic prefix (CP) and zero padding (ZP) techniques to achieve an error free communication. BER performance for OFDM with 16-QAM with varying length of GI was presented in this paper. In [5] the performance of OFDM- BPSK,-QPSK and -QAM system by using forward error correcting codes (convolutional , reed Solomon as well as concatenated coding) schemes that were used to encode the data stream in wireless communications AWGN channel has been reported. In [6] author investigated the bit error rate (BER) performance of Orthogonal frequency division multiplexing (OFDM)-Binary phase shift keying (BPSK) OFDM-Quadrature phase shift keying (QPSK), OFDM-Quadrature amplitude shift keying (QAM) over different fading channels. The performance of transmission modes were evaluated by calculating the BER versus signal to noise ratio (SNR) under the Additive white Gaussian noise(AWGN), Rayleigh fading, Rician fading, Nakagami-m fading channel. In [7] author investigated adaptive modulation & ICI self-cancellation methods for combating
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Performance Improvement of Wi-MAX System using QAM Modulation and Moving Average Filter

Performance Improvement of Wi-MAX System using QAM Modulation and Moving Average Filter

Abstract - WiMAX is introduced by the Institute of Electrical and Electronic Engineers (IEEE). Wireless provides a worldwide interoperability for microwave access. Now-a- days telecommunication industries are highly concerned with the wireless transmission of data, which can employ many transmission types, from point to multipoint links. It contains full mobile internet access. several applications have already been applied so far using Wi-MAX, as alternative to 3G mobile systems in developing countries, Wireless Digital Subscriber Line (WDSL), Wireless Local Loop (WLL). IEEE 802.16e-2005 has been developed for mobile wireless communication which is based on OFDM technology and this enables going towards the 4G mobile in the future. In this paper , we built a simulation model based on moving average filter implementation and demonstrated in different simulation scenarios with different modulation techniques such as BPSK, QPSK and QAM (Both 16 and 64) to find out the best performance of physical layer for WiMAX Mobile. All the essential conditions were implemented in the simulation according to the 802.16e OFDMA-PHY specification. The noise channel AWGN, Rayleigh fading, data randomization methods, FFT, IFFT, and Adaptive modulation is used for the whole simulation method. The performance has been concluded based on BER, SNR and Pe outcome through MATLAB Simulation.
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