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This paper presents pilot symbol aided channel estimation in Filter Bank Multicarrier (FBMC). FBMC has been employed widespread in communication applications because of its good spectral behaviors. Unlike Orthogonal Frequency Division Multiplexing, FBMC structure avoids imaginary interference. So that auxiliary symbols are employed and decrease peak to power ratio and improve achievable capacity....
Orthogonal Frequency division multiplexing is the modulation technique used for the fourth generation wireless communication system. In OFDM, Signals can be modulated by multiple carriers. OFDM uses the bandwidth of the spectrum efficiently. But the limitation of the OFDM system is the high Peak to Average Power Ratio (PAPR) which results in the degradation of the signal quality. Hence reducing the...
Multicarrier waveforms bring several major advantages over single carrier waveforms in radar systems: frequency diversity, waveform diversity, short time on target and the possibility to optimize the transmitted waveforms, to mention a few. Interesting waveform designs utilizing diversity have been proposed in the literature already. In this paper, we develop a generalized model that can accommodate...
The main disadvantage of the orthogonal frequency division multiplexing (OFDM) is the high peak-to-average power ratio (PAPR). To reduce the PAPR of the OFDM signals, this paper introduced and compared the three multiple signal representation methods, selected mapping (SLM), partial transmit sequences (PTS) and interleaving and presented their simulation results. Then combined interleaving with SLM...
When multiple users in an OFDM system can be synchronized, a novel efficient multiuser precoding approach for reducing out-of-band emission (OOBE) is developed. The main idea is to view all users as a virtual single user and design a common virtual precoder for all users. The precoder of a particular user is then constructed using the corresponding columns of the virtual precoder according to the...
A high peak-to-average power ratio (PAPR) is a major concern of an orthogonal frequency division multiplexing (OFDM) system. In this paper, a combination of pre-coding and clipping is used to reduce PAPR. This dual operation of pre-coding and clipping provides better PAPR than both conventional pre-coding and clipping method. With this technique, the PAPR can be reduced without increasing roll-off...
One of the main disadvantages of OFDM (Orthogonal frequency-division multiplexing) is its high PAPR (Peak to Average Power Ratio). In this paper we propose a method for reducing PAPR using encoding and companding techniques. Several codes were used such as BCH, RS codes and Reed-Muller. The effect of modulation BPSK and QAM16 on the PAPR has been studied, μ-law companding has been used and the influence...
A novel Peak to Average Power Ratio (PAPR) reduction method leveraging the rare occurrence of large magnitude Orthogonal Frequency Division Multiplexing (OFDM) symbols is proposed. A distinct innovation of this approach is the exploitation of the sparseness structure of a bit-plane binary number representation of time domain OFDM symbols. By encoding the sparsely populated non-zero entries in the...
Peak-to-average Power Ratio(PAPR) is considered as one of the serious side-effect of the OFDM system, which affects the efficiency of the amplifier. In this paper, we proposed a pre-coding scheme using a new encoding method of zerolization, which is based on the Information Gene(IG). The proposed technique is a new model of encoding that results as transforming no more than twelve zero and processing...
In this paper, the effective use of peak reduction carrier (PRC) for PAPR reduction is evaluated. By taking into account the number of PRCs, its position and PRC-to-data ratio, the recommendation on how to effectively adopt PRC for PAPR reduction is carried out for OFDM systems with sub-carriers from 64 sub-carriers to 8192 sub-carriers. From our simulations, it has been shown that there are effective...
Because the OFDM signal has higher Peak to Average Power Ratio (PAPR), the efficiency of Amplifier is badly influenced in Orthogonal Frequency Division Multiplexing (OFDM) system and caused signal distortion in-band. Therefore, reducing PAPR of OFDM signal is very important. The Partial Transmitted Sequences (PTS) method can effectively reduce PAPR of the OFDM signals, but the basic algorithm of PTS...
Although mobile communication technology in our country has experienced a rapid development, surfing the Internet wirelessly supported by the current technology of GPRS and cdma2000 has come true, mobile communication lags behind in our country and still can not meet the peoplepsilas needs that they need the higher data transmission in many multimedia operations. Therefore, many scholars in our country...
As a multicarrier signal can exhibit large peaks in the time domain, the amplifier used to transmit the multicarrier signal must be highly linear, and thus expensive, to avoid nonlinear signal distortion. To reduce the high peak-to-average power ratio, and hence to allow cheaper amplifiers, several techniques are described in the literature. However, the drawback of these techniques is that they cause...
First, an irregular repeat accumulate (IRA) coded orthogonal frequency division multiplexing (OFDM) system is introduced in this paper. To reduce the peak-to-average power ratio (PAPR) of this system, a balance sequence (BS) is inserted in the information bits. The BS can be determined by exhaustive search in the encoding process. But when the length of the BS is long, the time of searching may increase...
Multicarrier Code-Division Multiple Access (MC-CDMA) is a foreseen technique for future high data rate and high capacity multiuser wireless communications. However, the often large values of the Peak-to-Average Power Ratio (PAPR) of the transmitted signals pose a problem in multicarrier systems, because they can lead to nonlinear distortion at the High Power Amplifier (HPA) and a subsequent degradation...
In this paper, we propose a PAPR reduction method for a 16-QAM OFDM system by combining the BCM scheme with PTS technique, called BCM-PTS. We use four binary Reed-Muller codes as the BCM component codes to construct a 16-QAM BCM code and decompose this code as direct sum of a correction subcode for encoding information bits and a scrambling subcode for encoding PAPR bits. The PAPR bits are reserved...
Selected Mapping (SLM) is a popular technique used for Peak-to Average Power (PAPR) reduction in OFDM systems. Normally SLM techniques require explicit side information to be transmitted to allow decoding at the receiver. Alternative SLM techniques use shift register scramblers to embed the side information into the transmitted OFDM symbols. In this paper the concept of an SLM Simplified Scrambler...
The modern telecommunication industry demands higher capacity networks with high data rate. Orthogonal frequency division multiplexing (OFDM) is a promising technique for high data rate wireless communications at reasonable complexity in wireless channels. OFDM has been adopted for many types of wireless systems like wireless local area networks such as IEEE 802.11a, and digital audio/video broadcasting...
In OFDM, the orthogonal subcarriers can be assumed to undergo flat fading in a frequency selective channel permitting operation without an equalizer especially when differential data encoding is used. However, in CE-OFDM, the data symbols are no longer confined to orthogonal subcarriers and, therefore, an equalizer is required for operation in frequency selective channels. A frequency domain equalizer...
Orthogonal frequency division multiplexing (OFDM) is a technique that provides high data rate communications, but it is sensitive to the carrier frequency offset (CFO) caused by the misalignment in carrier frequencies between transmitter and receiver, which results in Inter-Carrier Interference (ICI) among the sub-carriers and degrades the Carrier-to-Interference Ratio (CIR). In this paper, we propose...
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