The Research Of RACH In The LTE

After the third generation mobile communication, the long term evolvement (LTE) brings new chance and challenge. In order to enhance the place of our country in the communication filed, we have do lots of hard work.In this paper Chapter 1 introduce the theory of ALOHA technology and how to implement the RACH in the WCDMA system. Chapter 2 overviews some concepts of RACH, and its purpose . Chapter 3 A kind of GCL(Generalized chirp-like) sequences are adopted as the preambles of the random access channel(RACH). This structure can utilize the perfect periodic correlation properties of GCL sequences effectively to improve the detection performance. Furthermore, a kind of detection algorithm is proposed, which is based on the peak-average ratio detection within a window. both false alarming probability and missing detection probability are analyzed. The possibility to adapt the proposed algorithm to be used as collision detection algorithm and channel estimation algorithm is also analyzed. Analysis and simulation results show that the proposed preamble structure and the corresponding detection algorithms have good performance. Chapter 4 A "time-slotted" structure is designed to lower collision probability with limited number of preamble sequences. Preambles detection algorithm and the threshold are well designed and the detection performance is analyzed. The collision probability is also analyzed. Analysis and simulation results show that the proposed structure has very good performance.