The Research Of Continual Phase Modulation Technology In The Next Generation Communication Systems

For the increasing demands of high-speed data and multimedia services, the fourth generation mobile communications systems should provide higher data transmission rate and reliability. But with the limitations of the reliable wireless frequency resource and the time-varying nature of wireless channel, communication systems always have low spectrum utilization and high code error ratio. So, how to provide both higher data transmission rate and reliability will be the main challenges for the future wireless communications.Multiple-Input Multiple-Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) techniques are widely recognized as the core technologies of the physical layer for the fourth generation (4G) mobile communication systems. MIMO technology uses multiple transmitting antennas and receiving antennas which can significantly improve the wireless communication system channel capacity and enhances the reliability of data transmissions. OFDM technology can make the frequency selective fading channel into a group of orthogonal flat fading channel to overcome the impact of multipath fading. Continuous-phase modulation (CPM) signal is a kind of constant envelope, continuous changed phase signal. It has smaller sidelobe spectrum, which has higher bandwidth utilization. CPM system's power amplifiers can work at the C state (non-linear) which get higher efficiency. OFDM, MIMO and CPM the three advanced technologies can be combined together to greatly improve the system performance.This thesis first researches the related principles of MIMO, OFDM and CPM. Followed by the introduction of a multi-antenna multi-carrier continuous phase modulation system—the VBLAST-OFDM-CPM system, focuses on the system model, system principle and performance analysis. Last we introduce one algorithm which uses CPM in the OFDM modulation system to reduce the PAPR that is called the sub-carrier group CPM algorithm. In this paper, the completion of the main points and the innovations include:1. A multi-antenna multi-carrier phase modulation system is submitted which put the CPM modulation into the MIMO-OFDM system to greatly improve the system's bandwidth utilization and efficiency of the amplifier. The system is characterized by multi-CPM-band technology, a number of M-ary, modulation index h and a reasonable number of antennas can be chosen easily. We use the MATLAB simulation to show a comparative analysis of system performance with various parameters.2. We propose a sub-carrier grouped CPM algorithm to reduce the OFDM system PAPR. The algorithm is characterized by no increasing of power and redundancy in the system, a significant reduction in the system PAPR and almost no loss of BER.3. The best modulation index values of M-ary CPM are put forward to in this thesis. For example, for 2CPM, 2 / 3 is the best h value which has the best BER performance; for 4CPM, 2/5 and 4 / 5 are the best; for 8CPM, 2 / 9,4 / 9 and 8 / 9 are the best h values.