The Detection Algorithm And System Performance Of V-OFDM System

OFDM is the core technology of 4G standards, which can realize the high rate data transmission and take full advantage of spectrum resources, meanwhile against the ISI effectively. But it still has main problems such as high peak-to-average power ratio (PAPR). SC-FDE is another communication system which can reduce the PAPR and maintain low complexity. Even though the data tramsfer rate and channel capacity are lower than OFDM, but it can also against frequency selective fading and coexist with OFDM in a bidirectional transmission system.This paper studies the V-OFDM system, which proposes the concept of vector unit. The V-OFDM integrates the advantages of OFDM and SC-FDE system. So it can not only against frequency selective fading, but also makes full use of spectrum resources. In practice, we can change the length of vector unit flexibly to adapt to the users’requirements of communication systems, such as data transfer rate, bit error rate, system cost and so on. In another word, OFDM and SC-FDE are two extremes of V-OFDM system.This paper analyzes detection algorithms in the receiving end, like Zero forcing, Minimum Mean Square Error, Successive Interference Cancellation, Maximum Likelihood and Sphere Decoding. According to the simulation, when using the ML to detect signal, the BER is the least. But the computing complexity increases dramaticly when the length of vector unit increases. The computing complexity of SD has nothing to do with the length of vector unit. The BER of system using MMSE is between the ML and SD when the SNR is low, which is slightly higher than SD when the SNR is high.We also analyze the influence of length of vector unit and the total number of channel taps to the V-OFDM system. Meanwhile we analyze the differences of BER of different vector units.