International Research Journal of Engineering and Technology (IRJET) Volume: 04 Issue: 02 | Feb -2017
www.irjet.net
e-ISSN: 2395 -0056 p-ISSN: 2395-0072
An Enhanced Technique for PAPR Reduction in Mobile WIMAX Amita Dogra1, Maninder Kaur2 Electronics Department, Doaba engineering college, Punjab, India HOD, Electronics Department, Doaba engineering college, Punjab, India
---------------------------------------------------------------------***--------------------------------------------------------------------Keywords: Broadband services, Mobile WIMAX, Abstract - High PAPR is an serious defect in optical OFDM PAPR, Frequency Division Multiple Access (OFDM), systems, deteriorating nonlinear impairment in optical DST (Discrete Sine Transform Matrix) fibers. This investigates the peak-to-average power ratio (PAPR) theory in the optical orthogonal frequency division multiplexing (OFDM) in the optical fiber communication systems. Many standards in wireless such as (Wi-Max, IEEE802.11a, LTE, DVB) has used the OFDM technology to increase dramatically future wireless communications. On the other hand, WiMAX is one of the hottest broadband wireless technologies nowadays. WiMAX systems are used to deliver broadband access different services to customers in an economical way. But, due to outside interference, these (WIMAX and OFDM channels) experience the negative effect of a higher value of peak to average power ratio (PAPR or we also call it crest factor). The main disadvantage of the OFDM has its high PAPR (Peak to Average Power Ratio). High PAPR is a serious intrinsic defect in many optical systems, deteriorating nonlinear impairment in optical fibers. We aim to reduce this value and provide a better communication channel. A peak to average reduction method that exploits the precoding and beamforming mode in WiMAX. the method is applicable to any OFDMA system that implements beam forming using dedicated pilots which use the same beam forming antenna weights for the data. The best solution of the multipath fading channel is multicarrier modulation techniques for wireless communication. An dummy sequence insertion technique and partial transmit sequence has been considered for PAPR and complexity reduction. comparison of fixed and mobile WiMAX systems using hybrid techniques for papr reduction partial transmit sequence and dummy sequence insertion techniques are well-known distortion less peak to average power reduction ratio techniques to improve the performance of orthogonal frequency division multiplexing systems. There are many techniques simulated for scalable OFDM system. The Reduction of PAPR problem is focused on many signal transformation. These techniques are used before amplification then inverse transforms at the receiver and before demodulation .This approach the transformed signal has best achievable PAPR and non-linear distortion are avoided, phase modulation is more preferable for PAPR reduction in the OFDM-based system. Š 2017, IRJET
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1. INTRODUCTION This increase in the broadband services used by all people all over the world. In order to achieve high data rates and to support all applications of broadband in a multipath environment, more effective modulation scheme in form of multicarrier scheme are adopted. this is Based on these the concept that WIMAX allows for an efficient use of bandwidth in wide frequency range and be used as a solution for broadband internet access. The effect of a high PAPR are the low power efficiency of the high power amplifier and signal distortion caused by operation in the non-linear region of the high power amplifier, low power efficiency needs large dynamic range. This increasing cost of the system and signal distortion induces degradation of the BER. PAPR reduction technique is used OFDM system have some disadvantages having large PAPR as well as high sensitivity to synchronization error to deal with this PAPR problem.Several techniques have been developed such as for instance coding and tone reservation clipping/filtering, peak windowing and receiver correction algorithm such as iterative decoding. An alternative way of reducing the PAPR problem is focused around signal transformation phase modulation. Phase modulation is more preferable for PAPR reduction in the OFDM-based system. For the digital modulation schemes, OFDMA is one of the multi-user version This Provides extensively low data rate transmission from several users. OFDMA can be said as an alternative to combining OFDM with time division multiple access (TDM . In this Low-data-rate users can be easily send continuously with low transmission power instead of using a "pulsed" high-power carrier. OFDMA can also be described as a combination of frequency domain and time domain multiple access ,hence the resources are partitioned in the time-frequency space, and slots are assigned along the OFDM symbol index as well as OFDM sub-carrier index. OFDMA is considered as highly suitable for broadband wireless networks, due to advantages such as scalability and the use of multiple antennas, and there ability to take advantage of various channel frequency selectivity .In various spectrum , OFDMA is an possible approach for filling various free radio frequency bands adaptively. OFDMA can be used in the mobility mode of ISO 9001:2008 Certified Journal
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