Research paper
OFDM
1.Abstract
Orthogonal Frequency Division Multiplexing (OFDM) is one of recently wide used technology in wire and wireless system .Now -a- days OFDM is also been used in the optical communications as well as in digital communications system and also has been adopted as the wireless LAN standard. This technology is used to overcome intersymbol interference which is caused by the dispersive channel. OFDM can be adopted in various ways to achieve a very good performance of the system. Some of the impairments are its high peak to average ratio power and its sensitivity to phase noise and frequency offset. This paper gives you to tutorial overview of the Orthogonal Frequency Division Multiplexing for communication systems and evolution throughout the years.
Introduction
Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM is a combination of modulation and multiplexing. The basic idea of OFDM to transport information is using a large number of parallel narrow-band subcarrier instead of single wide-band carrier .The basic concept of the OFDM is very simple . Data is transmitted in parallel on a number of different frequencies, and as a result the symbol period is much longer than for a serial system with the same total data rate. Because the symbol period is longer, ISI affects at most one symbol, and equalization is simplified. In most OFDM implementations any residual ISI is removed by using a form of guard interval called a cyclic prefix.
OFDM is essentially identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT), and is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. The word "coded" comes from the use of forward error correction (FEC). A large number of closely spaced orthogonal sub-carrier signals are used to carry data on several parallel data streams or channels. Each sub-carrier
1.Abstract
Orthogonal Frequency Division Multiplexing (OFDM) is one of recently wide used technology in wire and wireless system .Now -a- days OFDM is also been used in the optical communications as well as in digital communications system and also has been adopted as the wireless LAN standard. This technology is used to overcome intersymbol interference which is caused by the dispersive channel. OFDM can be adopted in various ways to achieve a very good performance of the system. Some of the impairments are its high peak to average ratio power and its sensitivity to phase noise and frequency offset. This paper gives you to tutorial overview of the Orthogonal Frequency Division Multiplexing for communication systems and evolution throughout the years.
Introduction
Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM is a combination of modulation and multiplexing. The basic idea of OFDM to transport information is using a large number of parallel narrow-band subcarrier instead of single wide-band carrier .The basic concept of the OFDM is very simple . Data is transmitted in parallel on a number of different frequencies, and as a result the symbol period is much longer than for a serial system with the same total data rate. Because the symbol period is longer, ISI affects at most one symbol, and equalization is simplified. In most OFDM implementations any residual ISI is removed by using a form of guard interval called a cyclic prefix.
OFDM is essentially identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT), and is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. The word "coded" comes from the use of forward error correction (FEC). A large number of closely spaced orthogonal sub-carrier signals are used to carry data on several parallel data streams or channels. Each sub-carrier