نتایج جستجو برای: papr

تعداد نتایج: 1538  

2013
Lavish Kansal

Orthogonal frequency Division multiplexing (OFDM) is the most familiar word in telecommunication and wireless communication systems as it provides enhanced spectral efficiency than Frequency division multiplexing (FDM).Although it is sustaining an orthogonal relation betweencarriers but high peak to average power ratio (PAPR) is one of the main disadvantages of OFDM system.Various PAPR reductio...

2015
J. P. Panwar

There are various issues related to OFDM such as dispersion (ICI), external interference (crosstalk) and nonlinearities (PAPR). OFDM suffers from a high Peak to Average Power Ratio (PAPR), caused by the addition of a large number of independently modulated sub-carriers in parallel at the transmitter. When subject to a non-linear power amplifier, these signals may undergo significant spectral di...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده فنی 1392

یکی از راه های مقابله با اثرات نامطلوب محوشدگی در کانال های فرکانس گزین بی سیم استفاده از تکنیک mimo-ofdm می باشد. سیستم های mimo با استفاده از چند آنتن در فرستنده و گیرنده چندگانگی فضایی ایجاد می کنند و اثرات نامطلوب محوشدگی در کانال های مخابراتی بی سیم را کاهش می دهند. در سیستم های mimo علاوه بر بهره گیری از مزایای چندگانگی می توان با استفاده از کدهای فضا- زمان یا فضا- فرکانس، از بهره ی کدی...

2012
Imran Baig Varun Jeoti

The mobile Worldwide Interoperability for Microwave Access (Mobile WiMAX) air interface adopts orthogonal frequency division multiple access (OFDMA) as multiple access technique for its uplink (UL) and downlink (DL) to improve the multipath performance. All OFDMA based networks including mobile WiMAX experience the problem of high peak-toaverage power ratio (PAPR). The literature is replete wit...

Journal: :IEEE Communications Letters 2021

Unique Word Orthogonal Frequency Division multiplexing (UW-OFDM) is a variant of the multicarrier technique that has shown better bit error performance compared to cyclic prefixed (CP-)OFDM. Like other techniques, UW-OFDM suffers from high peak-to-average-power ratio (PAPR) problem, which an obstacle ahead practical implementation UW-OFDM. In this letter, generator matrix, inherent UW-OFDM, not...

2015
Gaurav Kumar Meena

Orthogonal Frequency Division Multiplexing (OFDM) faces the Peak-to-Average Power Ratio (PAPR) problem that is a main disadvantage in multicarrier transmission system. Here in this paper an attempt is made to improve the spectrum efficiency (SE), and energy efficiency (EE) in orthogonal frequency division multiplexing (OFDM) systems, Simulation results show that the OFDM system with PAPR reduct...

Journal: :IEICE Transactions 2010
Lilin Dan Yue Xiao Wei Ni Shaoqian Li

This letter presents an improved peak cancellation (PC) scheme for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. The main idea is based on a serial peak cancellation (SPC) mode for alleviating the peak regrowth of the conventional schemes. Based on the SPC mode, two particular algorithms are developed with different tradeoff between P...

2013
Zhongpeng Wang

The precoding scheme based on real Hadamard transform is an effective and flexible way for reducing the peak-to-average power ratio (PAPR) of OFDM signals. However, the reduction capacity of PAPR is limited for real Hadamard transform method. In this paper, the new scheme based on complex Hadamard transform is proposed. The simulation results indicate that the proposed scheme may obtain a 1.2 d...

2017
D. Kiran Kumar M. Kailasa Reddy Sanjay Singh Nguyen Thanh Hieu Arvind Chakrapani Zhongpeng Wang Shaozhong zhang

This paper briefs about the Partial Transmit Sequences for Peak-to-Average Power Ratio Reduction of OFDM Signals, PAPR reduction efficiency of this method in comparison with Companding and Clipping and some merits and demerits of using various methods of PAPR reduction. Based on the above survey the criteria for the selection of PAPR reduction is given and proposed scheme of combining PTS appro...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده برق و کامپیوتر 1393

سامانه های مخابراتی دیجیتال نوین امکان استفاده همزمان از فناوریهای ofdm و mimo را در سامانه های mimo-ofdm فراهم نموده است. کارامدی ofdm در همسانسازی ساده کانالهای فرکانس- انتخابی و افزایش ظرفیت کانال بدون تغییر در پهنای باند و توان ارسالی با بهره گیری از فناوری mimo، توجه بسیاری از استانداردها و سامانه های مخابرات بیسیم را به خود جلب کرده است. یکی از عیبهای سامانه های mimo-ofdm نسبت بالای توان ...

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