: Neelam Dewangan
: A detailed Study of 4G in Wireless Communication: Looking insight in issues in OFDM
: Anchor Academic Publishing
: 9783954895847
: 1
: CHF 31.20
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: English
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As a promising technique, OFDM has been widely used in emerging broadband communication systems, such as digital audio broadcasting (DAB), high-definition television (HDTV), and wireless local area network (IEEE 802.11a and HIPERLAN/2). However, as the OFDM signals are the sum of signals with random amplitude and phase, they are likely to have large PAPR that require a linear high-power- amplifier (HPA) with an extremely high dynamic range which is expensive and inefficient. Furthermore, any amplifier nonlinearity causes intermodulation products resulting in unwanted out-of-band power. A number of approaches have been proposed to deal with the PAPR problem, including amongst others, clipping, clipping-and-filtering (CF), coding, companding transform, active constellation extension (ACE), selected mapping (SLM), and partial transmit sequence (PTS). This book proposes an improvement in the selected mapping technique. The resulting scheme can also be applied to the multiple transmitting antenna cases. Further, it compares the simulation results to the existing techniques namely exponential companding transform, repeated clipping and filtering, and adaptive active constellation extension.

Mrs Neelam Dewangan is an assistant professor at Chhatrapati /shivaji Institute of Technology, Durg. She has completed her M.Tech in communication engineering from the Chhatrapati /shivaji Institute of Technology, and under the supervision of Mr. Mangal Singh, the professor and head of the Institute. Moreover, she has published many papers and attended many conferences in her area of interest including wireless communication, 4G, LTE, and mobile communication.
Text Sample: Chapter 2.1, Different methods for Peak-to-Average Power (PAPR) Reduction in Orthogonal Frequency Division Multiplexing (OFDM): Himanshu Bhushan Mishra et al.in 2012 proposed a new Selective-Mapping (SLM) technique in WIMAX without side information which is the major issue in the classical SLM Technique. In this paper the PAPR performance is measured using complementary cumulative distribution function (CCDF) plot and the probability of SI detection error performance have been evaluated as the criteria for WiMAX standard IEEE 802.16e. WiMAX with its standard IEEE 802.16d/e is the advanced technology used for long range communication with high data rate. It is well known that the Orthogonal Frequency Division Multiplexing (OFDM) is a promising technique for getting high data rates in a multipath fading environment. Hence, the physical layer of WiMAX uses OFDM. But the main disadvantage of OFDM is the high peak to average power ratio (PAPR). In this paper PAPR reduction is achieved using selected mapping (SLM) technique and simultaneously without sending the side information (SI) along with the OFDM symbol [1]. E. Al-Dalakta et al. in 2012 proposed an efficient technique for reducing the bit error rate (BER) of Orthogonal Frequency Division Multiplexing (OFDM) signals transmitted over nonlinear solid-state power amplifiers (SSPAs).The proposed technique is based on predicting the distortion power that an SSPA would generate due to the nonlinear characteristics of such devices. Similar to the Selective-Mapping (SLM) or Partial-Transmit-Sequence (PTS) schemes, the predicted distortion is used to select a set of phases that minimize the actual SSPA distortion. Simulation results confirmed that the signal-to-noise ratio that is required to obtain a BER of ??10?^ (-4) using the proposed technique is less by about 8 dB when it is compared to the standard PTS utilizing 16 partitions. Moreover, complexity analysis demonstrated that the proposed system offers a significant complexity reduction of about 60% compared to state-of-the-art methods. This work demonstrated that less direct PAPR indicators can provide better performance when combined with distortion less techniques such as PTS and SLM. Therefore, the proposed techniques are optimized to combat the consequences of high PAPR rather than reducing the PAPR itself. The proposed techniques are based on using the distortion level to select the optimal PTS and S
A detailed Study of 4G in Wireless Communication1
Table of contents3
CHAPTER 1 Introduction7
1.1 Introduction to Long term evolution (LTE)7
1.2 Technologies involved9
1.3 Brief History of OFDM10
1.4 Basic Concepts12
1.5 Introduction to OFDM13
1.6 SC-FDMA and OFDMA Tx-Rx Structure17
1.7 Inter - Symbol Interference(ISI)19
1.8 Inter - Carrier Interference19
1.9 Understanding Concept of Cyclic Prefix19
1.10 OFDM using Inverse DFT22
1.11 Advantages of OFDM23
1.12 Disadvantages of OFDM23
1.13 Peak to Average Power Ratio24
1.14 PAPR Reduction Techniques24
CHAPTER 2 Literature Review26
2.1 Different methods for Peak-to-Average Power (PAPR) Reduction in Orthogonal Frequency Division Multiplexing (OFDM)26
CHAPTER 3 PROBLEM IDENTIFICATION34
3.1 Clipping and Filtering37
3.2 Coding38
3.3 Interleaving39
3.4 Companding40
3.5 Peak Windowing40
3.6 Additive Correcting Function40
3.7 Selected Mapping (SLM)41
3.8 Tone Reservation41
3.9 Tone Injection41
3.10 Selective Scrambling (Interleaving)42
CHAPTER 4 METHODOLOGY43
4.1 Objectives43
4.2 Hardware and Software Required43
4.3 Simulation model of OFDM System44
4.4Calculation of PAPR and CCDF of Original OFDM Signal46
4.5 Complimentary Cumulative Distribution Function (CCDF)47
4.6 Calculation of SNR and BER of Original OFDM Signal48
4.7 Criteria for selection of PAPR reduction techniques50
4.8 Definition of Efficient PAPR52
CHAPTER 5 PAPR REDUCTION TECHNIQUES53
5.1 SELECTIVE MAPPING54
5.2 Clipping - Based Active Constellation Extension Algorithm55
5.3 Exponential Companding Transform58
5.4 Adaptive Active Constellation Extension Algorithm60
CHAPTER 6 PROPOSED METHOD64
6.1 Selected Mapping With Riemann Matrix64
6.2 Concept of Riemann matrices65
CHAPTER 7 RESULTS AND DISCUSSION69
7.1 PAPR vs CCDF of Original OFDM Signal69
7.2 BER of Original OFDM Signal70
7.3 PAPR vs CCDF of OFDM Signal by using Selective Mapping (SLM) Technique71
7.4 CCDF Plot for Clipping-Based Active Constellation Extension (CB-ACE) Technique73
7.5 BER Plot for Clipping-Based Active Constellation Extension (CB-ACE) Technique74
7.6 CCDF Plot for Adaptive Active Constellation Extension (Adaptive -ACE) Technique76
7.7 BER Plot for Adaptive Active Constellation Extension (Adaptive -ACE) Technique77
7.8 CCDF Plot for Exponential Companding Technique78
7.9 BER Plot for Exponential Companding Technique79
7.10 CCDF Plot for Proposed Technique- SLM with Riemann Matrix80
7.11 BER Plot for Proposed Technique- SLM with Riemann Matrix81
CHAPTER 8 CONCLUSION AND FUTURE SCOPE83
RESEARCH PAPER PUBLISHED87
REFERENCES89