11-10-2010, 03:07 PM
In this article, a technique for combating the effects of multipath propagation and cochannel interference on a narrow-band digital mobile channel is analysed. DFT(discrete Fourier transform) is used by this method to orthogonally frequency multiplex many narrow subchannels. These subchannels each signaling at a very low rate are thus combined into one high-rate channel.The effects of flat Rayleigh fading can be reduced significantly when this method is used alongwith pilot-based correction technique. The signal-to-interference ratio can be improved upto 6 dB. The protection against delay spread can also be there. in a heavily frequency-selective environment , interpolated pilots are used. For improvement against co-channel interference,a frequency offset reference scheme is employed.
The mobile communication channel design is very challenging as the multipath propagation, arising from multiple scattering by buildings and other structures can severely affect the mobile transmission. Multipath fading may also be frequency selective. Also, the available radio channels are reused at different locations within the overall cellular service area in order to use the assigned spectrum more efficiently. When the mobiles use these channels simultaneously, there maybe problem of interference. In case of both speech and data transmission, the channel must provide good performance.
get the report here:
http://www.filesonicfile/24223203/OFDM mobile channel.pdf
The mobile communication channel design is very challenging as the multipath propagation, arising from multiple scattering by buildings and other structures can severely affect the mobile transmission. Multipath fading may also be frequency selective. Also, the available radio channels are reused at different locations within the overall cellular service area in order to use the assigned spectrum more efficiently. When the mobiles use these channels simultaneously, there maybe problem of interference. In case of both speech and data transmission, the channel must provide good performance.
get the report here:
http://www.filesonicfile/24223203/OFDM mobile channel.pdf