Introduction Proposed Method Experimental Results Conclusion References Partial Transmit Sequence (PTS) based PAPR reduction for OFDM using improved harmony search evolutionary algorithm BICT 2014 Mangal Singh, Sarat Kumar Patra Department of Electronics & Comm. Engg. National Institute of Technology, Rourkela, India 12/03/2014 1/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Proposed Method Experimental Results Conclusion References Overview Introduction 1 Proposed Method 2 Experimental Results 3 Conclusion 4 References 5 2/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Overview Introduction 1 Proposed Method 2 Experimental Results 3 Conclusion 4 References 5 3/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Introduction to OFDM Basic Idea Use large number of parallel narrow-band sub-carriers instead of a single wide-band carrier to transport information. Advantages Robustness against multipath fading . Low computational complexity & efficient hardware implemen- tation. Eliminates ISI through the use of cyclic prefix. Bandwidth efficient modulation scheme. 4/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Introduction to OFDM Disadvantages Sensitive to frequency synchronization problems. It is also sensitive to Doppler Shift. The peak to average power ratio of OFDM is also very high. High PAPR increases the complexity of ADC & DAC converters. High PAPR reduces the power efficiency and battery life. 5/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Figure 1: The block diagram of OFDM system 6/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Figure 2: Effect of PAPR in OFDM system 7/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Peak to Average Power Ratio (PAPR) Due to presence of large number of independently modulated sub- carriers in an OFDM system, the peak value of the system can be very high compared to the average of the whole system. As per the definition, PAPR of the transmitted signal is the ratio of peak power to the average power of the signal, i.e. PAPR = max | x n | 2 (1) � | x n | 2 � E 8/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Peak to Average Power Ratio (PAPR) Complementary Cumulative Distribution Function (CCDF) is used to represent performance measure for PAPR reduction techniques. It calculates the probability that the PAPR of a data block exceeds a given threshold PAPR 0 . The CCDF of the PAPR of N symbols of a data block with Nyquist rate sampling is defined as P r ( PAPR ≥ PAPR 0 )= 1 − P r ( PAPR ≤ PAPR 0 ) = 1 − (1 − e − PAPR 0 ) N (2) 9/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References PAPR Reduction Techniques PAPR Reduction Power Implementation Bandwidth BER Techniques Increase Complexity Expansion degra- dation Tone Reservation Yes High Yes No Tone Injection Yes High Yes No Clipping No Low No Yes Selective Mapping No High Yes No Partial Transmit No High Yes No Sequence 10/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Partial Transmit Sequence Technique (PTS) Basic Idea Among various PAPR reduction schemes, PTS is most suc- cessful technique for PAPR reduction, but the computational complexity is high due to searching of optimum phase factor. The complexity is proportional to the number of sub-blocks & phase factors used in PTS. Different optimization techniques can be used in PTS to reduce the searching complexity of the optimal phase factor. These optimization methods provides good PAPR reduction and computational complexity can be reduced simultaneously. 11/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Partial Transmit Sequence Technique (Conventional PAPR Reduction Scheme) Partial Transmit Sequence is a method for reducing PAPR by divid- ing bit stream in to few sub-blocks, then multiply the sub-blocks with few combination of phase rotation vectors and then finally choose the lowest PAPR in each sub-blocks. The input signal (candidate signal) is the sum of the products of phase rotation vector and corresponding sub-block. Thus, the can- didate signal is given by M x c = � T � b c x c 0 , x c 1 , ........, x c � m x m = (3) N − 1 m =1 where c = 1 , 2 , .. C 12/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References Figure 3: Traditional Partial Transmit Sequence Technique 13/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Orthogonal Frequency Division Multiplexing Proposed Method Peak to Average Power Ratio Experimental Results PAPR Reduction Techniques Conclusion Traditional Partial Transmit Sequence Technique References 16−QAM CCDF of OFDMA, 256−point 3000−blocks 0 10 No of subblocks= 1 No of subblocks= 2 No of subblocks= 4 No of subblocks= 8 No of subblocks=16 −1 10 0 ) Pr(PAPR>PAPR −2 10 −3 10 4 5 6 7 8 9 10 11 PAPR 0 [dB] Figure 4: PAPR vs CCDF of Traditional Partial Transmit Sequence 14/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Proposed Method harmony search algorithm Experimental Results improved harmony search algorithm Conclusion References Overview Introduction 1 Proposed Method 2 Experimental Results 3 Conclusion 4 References 5 15/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
Introduction Proposed Method harmony search algorithm Experimental Results improved harmony search algorithm Conclusion References Harmony Search Algorithm The harmony search Algorithm idealizes the improvisation process by a skilled musician.When a musician is improvising, a musician has three possible choices [1]: Play any famous piece of music (a series of pitches in harmony) exactly from the memory which corresponds to harmony mem- ory. Play something similar to a known piece (thus adjusting the pitch slightly) which corresponds to pitch Adjusting. Compose new or random notes which corresponds to random- ization. 16/31 Mangal Singh, Sarat Kumar Patra 12/03/2014 BICT 2014 Boston, Massachusetts, United States
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