Research On Key Technologies Of MC-CDMA

MC-CDMA is one the core technologies in 4G, which utterly combines the advantages ofCDMA and OFDM with good anti-jamming, signal's cover-up and good at resisting frequencyselective fading and inter-symbol interference, so researching on it is a trend and the significance isobvious.In this paper, firstly we present the characteristics of wireless channel, build up itsmathematical model, and use Matlab to simulate the model. The result of the simulations suppliesmany useful information for the estimation and analysis of the wireless channel's characteristics.Then a particular introduction of MC-CDMA is given, including its principle, characteristicsand mathematic model. We introduce the simulation process and illustrate each module. Next we domuch research on the methods of distributing the spreading sequence to sub-carriers, especially onthe continuous spreading and the discrete spreading method, and then propose a new method basedon them. We build up the model and analyze the three systems in mathematic method. Thesimulation result shows that the new system's performance is better than both the former.In the methods of user detection, we introduce EGC, MRC, ORC and MMSEC. It is veryimportant to use them to eliminate MAI. And we do a lot of simulations using each method indifferent conditions, so many results come out which bring us many conclusions.At last, we introduce adaptive resources distribution principle, optimiz ing rules and its systemmodel. According to the present three algorithms we propose a new adaptive distribution algorithmbased on RCG from literature[40] and make the implement process and simulate algorithm at thesame time. The results indicates that the performance of the new algorithm is the best of all thoughits complexity is a little bit higher than any other one.