单径或多径瑞利衰落信道仿真，用蒙特卡洛模拟的方法计算美式期权的价格以及基本描述,ldpc码的编解码实现。- Single path or multipath Rayleigh fading channel simulation, Monte Carlo simulation method of calculating the American option price and basic descr iption, Codec ldpc code implementatio.