Random Access Method in Long Term Evolution System

Abstract

The invention discloses a random access method in a long-term evolution system. UE performs priority judgment according to the purpose of random access, and if high priority is satisfied, then selects and sends two adjacent random access preambles; eNB judges to receive Whether there is an adjacent random access preamble in the random access preamble of the random access preamble, and if it exists, in the random access response message sent for the adjacent random access preamble, set the uplink transmission delay indication to a different value ; If it is a high-priority random access UE, send the same MSG3 message respectively according to the UL Grant allocated in the received two different random access response messages; eNB receives and demodulates the MSG3 message, if two MSG3 If the message contains the same contention resolution identifier, only the time-frequency resource required for one data transmission is allocated to the UE. By applying the present invention, the random access success rate of high-priority UE can be improved without changing the current LTE protocol specification.

Description

technical field [0001] The present invention relates to a random access technology in the communication field, in particular to a random access method in a Long Term Evolution (LTE, Long Term Evolution) system. Background technique [0002] Random access technology is an important technology for media access control in communication systems. In the Time Division Duplex (TDD, Time Division Duplex) mode of LTE systems, random access is the The access process before communication is mainly used for the initial registration of users and the application of user resource bandwidth. [0003] According to the definition of the latest version of the existing LTE protocol, random access is mainly asynchronous random access. And according to different purposes of access, random access is divided into five categories: the first category is random access requesting initial access; the second category is random access during radio resource control (RRC, Radio Resource Control) connection...

AI Technical Summary

Problems solved by technology

However, if different UEs select the same random access preamble and request random access on the same random access channel, the base station will only detect that a UE has sent the random access preamble, and cannot distinguish between sending the random access preamble. Random access to different UEs corresponding to the preamble, and for the random access preamble, allocate the same random access time-frequency resources for different UEs, and return the same random access response message; the UE receives the random access response message Afterwards, different UEs will simultaneously transmit their MSG3 messages on the same random access time-frequency resource, resulting in transmission collisions between MSG3 messages, making the base station unable to correctly receive and demodulate the MSG3 messages of different UEs , resulting in the failure of this random access, resulting in a low random access success rate of the UE. For some important UEs, the low random access success rate will greatly affect the transmission of their data services

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