近來,隨著寬頻技術的發展，人們可以擁有更多的資訊服務，例如：語音、視訊、多媒體及寬頻資訊服務。然而，人們所提出的3G系統並無法真正達到2-Mbps的標準傳輸速率，事實上最高只能達到384-Kbps的速度，要達到真正寬頻的服務，整套系統必須躍升到第四代行動通訊網路才能實現。在第四代行動通訊之中，人們提出多載波調變(Multi-Carrier Modulation；MCM)技術，它的優點是在於頻率選擇性衰減(frequency selective fading)的環境中有較佳的表現。多載波分碼多重存取(Multi-Carrier Code Division Multiple Access；MC-CDMA)技術，為一種多載波調變技術，其包含分碼多重存取(Code Division Multiple Access；CDMA)及正交分頻多工(Orthogonal Frequency Division Multiplexing；OFDM)技術。
本論文在接收機部分使用最小均方誤差組合(Minimum Mean Square Error Combining；MMSEC)的檢測方法，分別在可加性的白色高斯雜訊通道(Additive White Gaussian Noise)及頻率選擇性衰減通道下分析與模擬，並針對系統參數的不同加以討論。

Recently, as the broadband technology increases, people can have many different kinds of broadband service. For example, voice, video, multimedia and a great quantity of data services. However, the architecture of 3G systems cannot truly provide the broadband service. Originally it maintains the possible 2-Mbps data rate in the standard, but it will realistically achieve 384-kbps rates. To achieve the goals of true broadband service, the systems have to make a leap to the fourth-generation (4G) systems.
In the 4G systems, the Multi-Carrier Modulation (MCM) technique is proposed. The MCM’s advantages include better performance in the frequency selective fading channel. MC-CDMA scheme is one of the MCM techniques that combination of CDMA and OFDM schemes.
In this thesis, the system models include the transmitter model, channel models and receiver model. The channel model is based on AWGN and frequency selective fading channel. In the receiver model, we use the Mean Square Error Combining (MMSEC) method for the detection scheme. In the numerical simulation results of the OFDM system and the MC-CDMA system include the different values of parameters in AWGN channel and frequency selective fading channel.

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