LTE RACH Procedure Enhancement

摘要

Methods and apparatus are provided for Msg3 collision resolutions. In one embodiment, the UE obtains a set of DMRS seeds and randomly selecting one to generate a DMRS sequence for the Msg3. The set of DMRS seeds is either generated based on a received cell-specific parameter or are received from the network. In another embodiment, the eNB, upon detecting the collision in Msg3, indicates a lowered MCS level for the Msg3 transmission in the RAR after the preamble detection. In another embodiment, the early termination of Msg3 transmission is used upon determining the collision of Msg3. In one embodiment, the eNB responds an ACK to a failed Msg3 to suspend the re-transmission of the Msg3. In another embodiment, the eNB sends a flag to cancel the mac-ContentionResolutionTimer and terminate the Msg3 transmission. The termination indication is either embedded in the acknowledgement signaling or sent through PDCCH signaling.

主权项

1. A method, comprising:
sending a random access channel (RACH) preamble by a user equipment (UE) to a base station in a wireless network; receiving an uplink (UL) grant from the base station, wherein the UL grant includes a random access preamble identification (RAPID); performing a Msg3 collision resolution procedure that terminates a Msg3 transmission or retransmission before a maximum number of Msg3 retransmission is reached.