Study On Lte Downlink Pre - Coding And Its DSP Realization

LTE(Long Term Evolution),as a evolution of the 3G technology which is called 3.9G, is designed to satisfy the growing demands of communications in our generation. LTE uses MIMO(Multiple-Input Multiple-Output) and OFDM (Orthogonal Frequency Division Multiplexing) precoding technology and the specification has defined the different scheme of MIMO precoding, including the transmit diversity, the spatial multiplying, beaforming and so on.First of all, the LTE theory is introduced, including OFDM, SU-MIMO, MU-MIMO, LTE precoding scheme and so on.In addition, it emphatically research on two parts of the LTE technology: codebook-based and CDD-based precoding.In study of the codebook-based precoding,the Unitary codebook-based precoding and the Non-Unitary codebook-based precoding are firstly compared. Based on this reaserch, it proposes the SINR-based codebook selection algorithm for receiver and finally uses matlab to simulate the preformonce of the LTE downlink precoding.As the same way, the closed-loop spatial multiplexing transmission mode (CDD-based) precoding has been researched emphatically which is based on the CDD precoding.Then the algorithm of the large delay CDD precoding is improved to reduce the complexity of the UE receiver.Finally, it introduces the process of realizing the downlink precoding which is based on the six cores DSP MSC8156, and then analyses the newest Multi-DSP. The derection of the next step research has been clearly shown after summarizing all the researchs of this article from theory to realization.