Lte Channel Estimation Based On Dif-Ferent Pilot Patterns

Wireless communication has become an essential part of everyday life. As the demand to higher rate of data transmission, lower delay expe-rience and more diverse data to support growing, the core technologies of LTE:Orthogonal Frequency Division Multiplexing (OFDM) and Multi-ple-Input Multiple-Output (MIMO) has become a hot research topic. However, to realize the improvement of system performance through the adoption of OFDM, the research on related core technologies mustn’t be ignored, where the channel estimation is the key point. The channel esti-mation in LTE is based on the theory of non-blind channel estimation, through inserting reference signals into the physical resource blocks which the data transmitted occupied, then the receiver uses related rules of channel estimation and interpolation algorithms to estimate the channel information to serve the following coherent demodulation. So, how to de-sign the pilot insertion position, not only meeting the need of channel correlation but also obtaining the best channel estimation performance while using the same number of pilots has become a problem to face.This paper points out that the pattern of Demodulation Reference Signal (DMRS) makes the data transmission stiffness due to its constraint to guarantee the same number of subcarriers that reference signal se-quence matching the wireless communication bandwidth and its perfor-mance against decline and suppressing interference needs to be improved, through analyzing the structure. Considering the frequency diversity and interference suppression, we proposed the DMRS pattern redesign based on frequency hopping. With the introduction of frequency hopping, the data transmitted and reference signal inserted will be mapped into differ-ent physical resource blocks, in the meanwhile, remain continuity in each physical resource block. Then according to different scenarios, a contrast in Block Error Rate (BLER) of original DMRS pattern and DMRS pat-tern redesigned based on frequency hopping is given. Simulation proves that such changes can make sense on eliminating Rayleigh fading and suppressing interference.Finally, we make a brief extension on D2D communication applied to LTE system. Considering the RF performance and energy consumption at terminals, SC-FDMA is suggested to be its multiple access technology. As for the pilot pattern, the DMRS is chosen as the original reference signal, and the frequency hopping is also adopt to redesign the DMRS pattern. Simulation proves the feasibility of the D2D communication sys-tem based on LTE.