The Study On Rake's Receiving Technology In CDMA System

In mobile communication system, due to electronic wave is subject to the city building and terrain, it's bound to appear different route and time delay, namely, the channel of mobile correspondence is a various declined channels, it makes the received signal undulate and decline, this leads to affect the quality of correspond system .In CDMA system, Rake receiving is a very effective method against the various routes declined, so-called Rake receive technique is a separable demodulation for every received signals ,and putting output together to achieve the aim of enhancing the effect of receiving .Here ,the various routes signals is not an un-favorable factor ,but it becomes a beneficial one in CDMA system .This paper stress on describe the Rake receive technique .Because of the complex circumstance and the continuous movement of mobile telephone, the received signals frequently come from many over lapped reflected wave, so form various route declined. CDMA system adopts the unique Rake received technique that demodulates every routes signal separately. Like this, not only do it overcome the influence of various routes decline, but also it equal to it add up the power of signal (so to speak equaling to increase the launch power of signal). In addition, CDMA system even more select and use "scattering-concentrate" technique, for instance space "scattering-concentrate", Time "scattering-concentrate", improving still further the capacity of system.From the glitch of various routes transmitting of microwave, the article points out the measure to conquer route transmitting - adopt "Rake "technique.This article commends the principle of the Rake receiver, then focus on the pattern and achievement of Rake receive of CDMA system.