2 OFDM SYSTEM:-
OFDM system is divided into three parts 1. multi carrier modulation 2. frequency division multiplexing 3. Orthogonal frequency division multiplexing.
1.Frequency division multiplexing:- Frequency Division Multiplexing is a form of signal multiplexing which involves assigning non – overlapping frequency ranges or channels to different signals or to each user of a medium. A gap is left between each of these channels to ensure that the signal of one channel does not overlap with the signal from an adjacent one. because of scarcity of digital filters it was very difficult to filter closely packed adjacent channels.
2.Multicarrier modulation:- it is not convenient and efficient to transfer a high rate data stream through a channel, the signal is divided into a number of signals over that frequency range. Each of these signals are individually modulated and transmitted over the …show more content…
1.provides Immunity to selective fading: One of the main advantages of OFDM is that is more resistant to frequency selective fading than single carrier systems because it splits the overall channel into multiple narrowband signals that are affected individually as flat fading sub-channels. 2.Resilience to interference: Interference appearing on a channel may be bandwidth limited and in this way will not affect all the sub-channels. This means that not all the data is lost. 3.Spectrum efficiency: Using close-spaced overlapping sub-carriers, a significant OFDM advantage is that it uses spectrum efficiently. 4.Resilient to inter symbol interference : Another advantage of OFDM is that it is very resilient to inter-symbol and inter-frame interference. This results from the low data rate on each of the
OFDM system is divided into three parts 1. multi carrier modulation 2. frequency division multiplexing 3. Orthogonal frequency division multiplexing.
1.Frequency division multiplexing:- Frequency Division Multiplexing is a form of signal multiplexing which involves assigning non – overlapping frequency ranges or channels to different signals or to each user of a medium. A gap is left between each of these channels to ensure that the signal of one channel does not overlap with the signal from an adjacent one. because of scarcity of digital filters it was very difficult to filter closely packed adjacent channels.
2.Multicarrier modulation:- it is not convenient and efficient to transfer a high rate data stream through a channel, the signal is divided into a number of signals over that frequency range. Each of these signals are individually modulated and transmitted over the …show more content…
1.provides Immunity to selective fading: One of the main advantages of OFDM is that is more resistant to frequency selective fading than single carrier systems because it splits the overall channel into multiple narrowband signals that are affected individually as flat fading sub-channels. 2.Resilience to interference: Interference appearing on a channel may be bandwidth limited and in this way will not affect all the sub-channels. This means that not all the data is lost. 3.Spectrum efficiency: Using close-spaced overlapping sub-carriers, a significant OFDM advantage is that it uses spectrum efficiently. 4.Resilient to inter symbol interference : Another advantage of OFDM is that it is very resilient to inter-symbol and inter-frame interference. This results from the low data rate on each of the