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URN etd-1220105-162402 Statistics This thesis had been viewed 3453 times. Download 1843 times. Author Shuh-Tung Shiu Author's Email Address email@example.com Department Communication Engineering Year 2004 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 106 Title REDUCTION OF PAPR FOR OFDM BY BCM Keyword Primitive polynomial code High PAPR Block Coded Modulation Block Coded Modulation High PAPR Primitive polynomial code Abstract High Peak to Average Power Ratio (PAPR) is a drawback of OFDM system, especially in large OFDM system for providing high bandwidth demands in the market. Today WLAN IEEE802.11a and 802.11g only implement 64 subcarriers for operation, in some digital broadcasting systems such as 802.16e, digital TV or DVB, the number of subcarrier can be 2048 or even up to 8000.
Since PAPR is proportional to the number of subcarriers, and high PAPR OFDM signal will push power amplifier operated in non-linear zone that will impact system performance by distortion and high order harmonics.
There are many proposals have been proposed to reduce PAPR, amount of those proposals, Block Coded Modulation (BCM) is one of the simplest solutions to reduce PAPR, it also provide error check capability in noisy and fading transmission environment.
Here, we are proposing BCM with proper degree of good code (selected primitive polynomial codes) to reduce PAPR. The basic design rules will considerate the number of subcarrier and highest modulation scheme to determine a proper degree of BCM code for PAPR reduction, different scale system will use different degree of BCM codes for system.
During the research, we realized not every primitive polynomial codes has good properties to spread information to randomness. The seed will also change the sequence of bit stream and autocorrelation.
For speed up the primitive codes searching, we developed “Liner Magnify”, simple tools for periodic cycles searching; it is a handy tool in primitive code searching and good code verifying. In simulation chapter, we are using proper degrees good code for PAPR reduction base on system design rules, the simulation result indicate BCM can control the reduce PAPR from high PAPR 45dB to 10~12dB in 256QAM and 32000 subcarrier large scale OFDM system.
Advisor Committee Chau-Yun Hsu - advisor
none - co-chair
none - co-chair
Files Date of Defense 2004-07-15 Date of Submission 2005-12-20