ABSTRAKSI: Peningkatan penggunaan komunikasi data dan peningkatan pembangunan infrastruktur pada area urban/metropolitan disertai dengan mobilitas user yang tinggi adalah beberapa hal yang mempengaruhi masalah propagasi sinyal, sehingga dapat mempengaruhi kualitas layanan komunikasi. Penerapan teknik sistem komunikasi koheren kanal, pada perangkat pengirim maupun penerima, dapat menjaga kualitas layanan, dengan menggunakan estimasi kanal. Penerapan estimasi kanal ini merupakan solusi ideal, namun hal tersebut akan sangat sulit direalisasikan karena kompleksitas sistem yang begitu rumit untuk diterapkan pada kanal yang bersifat fast fading. Modulasi OFDM mendukung komunikasi pita lebar dengan laju data tinggi dan dapat menangani frequency selective fading, namun belum dapat mengatasi kondisi fast fading sehingga masih membutuhkan teknik multicarrier tertentu untuk menangani kondisi tersebut. Sistem komunikasi non-koheren pada kanal menjadi solusi alternatif, karena tidak membutuhkan carrier recovery pada penerima. Lebih sederhana dibandingkan dengan sistem komunikasi koheren kanal, teknik modulasi CCK menerapkan sistem komunikasi non-koheren yang cukup handal dalam mengatasi kondisi fast fading. Teknik modulasi ini menerapkan DQPSK, differential modulator pada pengirim dan Modified-FWT disertai channel match filter dan correlator yang berfungsi sebagai rake receiver pada penerima sehingga sistem ini dapat mengatasi pengaruh kanal multipath. Pengkombinasian antara CCK dengan OFDM dalam mengatasi kanal multipath dan mobilitas user yang tinggi terbukti dapat memberikan peningkatan performansi yang ditunjukkan melalui kurva BER terhadap Eb/No.Kata Kunci : CCK, OFDM, DQPSK, Binary Complementary Code, Polyphase Complementary Code, BER vs Eb/No, Fast Fading, Multipath FadingABSTRACT: The increased use of data communications and improved infrastructure in the area of urban / metropolitan and the high user mobility are some factors that produce signal propagation problems. These problems affect the quality of communication services. The application of coherent channel communication system , on the transmitting and receiving devices, is able to maintain the service quality by means of channel estimation . The application of the estimated channel is an ideal solution; however, the implementation is very difficult due to the sophisticated system when it is applied to fast fading channels. OFDM modulation supports wideband communications with high data rate and handles frequency selective fading, but it is not able to overcome the problems of fast fading conditions. Therefore to handle this condition, this requires a particular multicarrier technique. The Non-coherent communication system on the canal could become one of the alternative solutions, because it did not require carrier recovery at the receiver. This technique was simpler than the coherent channel communication systems because this CCK modulation technique applied reliable non-coherent communication systems to overcome the fast fading conditions. This modulation implemented DQPSK, a differential modulator on the sender and a Modified-FWT with channel match filter and correlator functioning as a rake receiver at the receiver so that this system was able to overcome the effect of multipath channels. This study showed that the integration of CCK and OFDM to overcome the multipath channels and the high user mobility had improved the performance shown by the curves of BER for Eb / No.Keyword: CCK, OFDM, DQPSK, Binary Complementary Code, Polyphase Complementary Code, BER vs Eb/No, Fast Fading, Multipath Fading