A novel multiple access scheme using MSE-OFDM for uplink (original) (raw)
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Multiple Access Scheme for Multi-Symbol Encapsulated Orthogonal Frequency Division Multiplexing
The International journal of Multimedia & Its Applications, 2011
A new multiple access scheme using Multi-Symbol Encapsulated Orthogonal Frequency Division Multiplexing (MSE-OFDM) is proposed. This is basically a time division multiple access (TDMA) technique utilizing the MSE-OFDM. The Bit Error Rate (BER) performance of the TDMA system using conventional OFDM is slightly better than that of the proposed system. This weakness is compensated as the proposed technique exhibits an improvement in bandwidth efficiency compared to the TDMA using conventional OFDM.
MSE-OFDM: a New OFDM Transmission Technique with Improved System Performance
Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005., 2005
A new multicarrier system, termed Multi-Symbol Encapsulated Orthogonal Frequency Division Multiplexing (MSE-OFDM), was proposed, in which one cyclic prefix (CP) is used for multiple OFDM symbols. The motivations for this new OFDM system are either to reduce the redundancy caused by the CP or to increase the system robustness to frequency offset, depending on the two different proposed implementations for the MSE-OFDM systems. The corresponding frequency offset and channel estimation algorithms are investigated. Possible ways to reduce the complexity of the joint maximum likelihood (ML) estimator, including the approximation of the joint ML estimator and FFT pruning, are discussed. The performance of the proposed estimators is also analyzed and verified through numerical simulations.
O Performance Comparison of Cyclic Prefix OFDM and Unique Word OFDM in the LTE Downlink
2016
The Long Term Evolution (LTE) downlink frame structure currently uses Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) where the bandwidth occupied by the prefix is not utilized. Optimization of this prefix could result in increased throughput and bandwidth efficiency. This paper investigates the benefits of exploiting the unused bandwidth occupied by CP in the LTE downlink frame structure by replacing it with a newly recognized bit sequence known as the unique word (UW). A modelling and simulation approach under Matlab Simulink software was adopted. The Orthogonal Frequency Division Multiplexing (OFDM) was first modelled and tested with a 2 x 2 Multiple-In-Multiple-Out (MIMO) system while the CP and UW where implemented and tested respectively for the same input parameters. Metrics of comparison included Channel Bandwidth, number of control symbols, Modulation type, coding rate and Signal-to-Noise-Ratio (SNR) as per the LTE standard. In short, the power spectral d...
On the Design and Performance Analysis of Multisymbol Encapsulated OFDM Systems
IEEE Transactions on Vehicular Technology, 2006
Abstract A new multicarrier system, termed multisymbol encapsulated orthogonal frequency division multiplexing (MSE-OFDM), is proposed, in which one cyclic prefix (CP) is used for multiple OFDM symbols. The original motivation for the MSE-OFDM proposal is to reduce ...
A Review on Orthogonal Frequency Division Multiplexing (OFDM
Orthogonal frequency division multiplexing (OFDM) is a special case of multicarrier transmission where a single DataStream is transmitted over a number of lower rate subcarriers. In July 1998, the IEEE standardization group decided to select OFDM as the basis for their new 5-GHz standard aiming a range of data stream from 6 up to 54 Mbps. This new standard is the first one to use OFDM in packet-based communications. In wireless communication, concept of parallel transmission of symbols is used to achieve high throughput and better transmission quality. Orthogonal Frequency Division Multiplexing (OFDM) is one of the techniques for parallel transmission. The idea of OFDM is to split the total transmission bandwidth into a number of orthogonal subcarriers in order to transmit the symbols using these subcarriers in parallel. In this paper we will discuss the basics of OFDM technique, role of OFDM in this era, its benefits and losses and also some of its application.
IRJET, 2019
Orthogonal Frequency Division Multiplexing (OFDM) is a method of encoding the input data over multiple narrowband carriers. In this paper, QPSK modulation technique is used for OFDM. Delay spread in wireless communication introduces Intersymbol interference(ISI). OFDM mitigates the effect of ISI. When conventional OFDM is used for uplink, the problem with OFDM is peak-to-average power ratio(PAPR). PAPR reduces the power efficiency of the system. To mitigate the effects of PAPR, Super-Orthogonal Convolutional codes along with golay codes are used in OFDM. With reduced PAPR, OFDM signal is transmitted over Wireless communication channel. Wireless communication channel introduces fading under various conditions. In this Paper, OFDM signal is analyzed over AWGN, Rayleigh and Rician fading channels. In AWGN channel, the increase in Signal to Noise Ratio(SNR) reduces bit error rate(BER). In case of fading channels, the amount of fading in multipath component is an important parameter which decides BER. The effect of fading on OFDM signal is observed by simulation using MATLAB R2010a. The fading channel which suits OFDM is proposed.
Evaluation: OFDMA & SC-OFDMA Performance on Wireless Communication
This paper investigates OFDMA and SC-FDMA techniques combined with the Orthogonal Frequency Division Multiplexing (OFDM). Single carrier frequency Division Multiple Access(SC-FDMA) is a notable application of Multiple Input Multiple Output(MIMO) system. SC-FDMA is one of the most promising techniques aiming at solving the capacity problem of wireless communication systems and achieving higher spectral efficiency, depending on multiplexing signals based on their spatial signature. On the other hand most third generation mobile phone systems are using Code Division Multiple Access (CDMA) as their modulation technique. CDMA is not so complicated to implement as OFDM based systems. As CDMA has a wide bandwidth, it is difficult to equalize the overall spectrum - significant levels of processing would be needed for this as it consists of a continuous signal and not discrete carriers. Not as easy to aggregate spectrum as for OFDM. For this reason, CDMA is also investigating so that the performance of OFDM-SC-FDMA can be compared. Various OFDMA techniques are investigated including LTE or Long Term Evolution is the brand name given to the efforts of 3GPP 4th Generation technology development efforts mostly in Europe and UMB (Ultra-Mobile Broadband) is the brand name for similar efforts by 3GPP2, linear detection schemes, minimum mean square error, ordered successive cancellation, and maximum likelihood methods. Promising results are obtained to enhance spectral efficiency on the expense of computational complexity which needs to be addressed.
Performance Analysis Of Cyclic Prefix OFDM Using Adaptive Modulation Techniques
A Orthogonal Frequency Division Multiplexing (OFDM) scheme provides high spectral efficiency and better resistance to fading environments. In OFDM the data is modulated using multiple number of sub-carriers that are orthogonal to each other. The Inter Symbol Interference (ISI) and Inter Channel/Carrier Interference (ICI) are reduced to a great extent with use of OFDM. A guard time, in the form of Cyclic Prefix (CP) is inserted between OFDM symbols to eliminate both the lSI and ICI. In this article, OFDM based BPSK, QPSK and QAM modulation systems are demonstrated incorporating AWGN channels using MATLAB Simulink model. The performance of the system is evaluated in terms of BER. The effect of the CP on the BER is also evaluated for BPSK, 4-QAM, 16-QAM, and 64-QAM modulation schemes. INTRODUCTION The Cooper's law, an analogue of Moore's law, observes that wireless bandwidth, speed and capacity of the network has been doubling every after 2.5 years. The Orthogonal Frequency Division Multiplexing (OFDM), a next generation communication standard, can provide large data rates with sufficient robustness to multipath fading. WIMAX system based on OFDM provides a greater bandwidth compared to other broadband technologies like Wireless Fidelity (Wi-Fi) and Ultra Wideband (UWB). In this paper, the research is focused on the effects of BER with SNR and analyzed the effect of cyclic prefix in OFDM using different adaptive modulation techniques. OFDM has recently grown interest in the telecommunication industry due to the demand of higher data rates and enormous bandwidth of multimedia data transmission. The journey of the theoretical view of simultaneous data transmission through linear band limited channel without ISI and ICI started in December 1966 by Robert W. Chang [1]; later he obtained US patent on OFDM system in 1970. The performance analysis and its' drawback rectification is still a research challenge. In 1980, Peled & Ruiz [2] introduced cyclic prefix or cyclic extension of OFDM symbols instead using empty guard band in frequency domain by performing the circular convolution operation [3]. This method provides orthogonality over dispersive channels when cyclic prefix is longer than the channel impulse response. The advancement of digital signal processing (DSP) technology helps to the inclusion of discrete fourier transform (DFT) and fast fourier transform (FFT) with cyclic prefix in OFDM system. The commercial use of OFDM technology also act as a core technology of digital audio broadcasting (DAB) (1987), digita video broadcasting (DVB) (1993), and DVB along with high definition television (HDTV) terrestrial broadcasting standard (1995). Several wireless local area network (WLAN) and HyperLAN standards appointed OFDM in its Physical (PHY) layer model in 20 th century. The IEEE802.11a standard also hire OFDM standard in its PHY layer. This technology also plays an important role in future 5 th generation (5G) wireless system.