PRACH Preamble Configuration for Unlicensed Carrier Coexistence
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Solution Overview
Problem
Current LTE systems face interference issues when operating on unlicensed frequency spectrums, as they lack a mechanism to detect and avoid collisions with existing Wi-Fi devices, leading to access delays and inefficiencies in preamble sending.
Innovation Solution
A preamble configuration method and sending method are introduced, where a base station configures Physical Random Access Channel (PRACH) information, including sub-frame location, Clear Channel Assessment (CCA) interval, channel detection mechanism, and preamble format, which is then sent to user equipment to determine channel idle states and send preambles accordingly, reducing access delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE transmits continuously on unlicensed frequency spectrum without listening rules, then network capacity and service continuity are improved, but interference to Wi-Fi devices increases and fair coexistence deteriorates
Solution Approach 1:
The patent applies preliminary action by implementing Clear Channel Assessment (CCA) before transmitting on unlicensed carriers. The base station performs channel detection in advance to check if the channel is idle before initiating LTE transmission, thereby preventing interference to Wi-Fi devices while maintaining network capacity
Solution Approach 2:
The patent implements feedback mechanisms where the base station continuously monitors the unlicensed channel status and adjusts transmission behavior based on channel occupancy detection. This feedback loop enables dynamic adaptation to coexist fairly with Wi-Fi while maintaining optimal network performance
2Ease of operation
If LTE uses traditional random access on unlicensed carriers without channel detection, then access procedure simplicity is maintained, but access delay increases due to collisions and retransmissions
Solution Approach 1:
The patent applies preliminary action by requiring user equipment to perform channel detection before sending random access preambles on unlicensed carriers. This advance checking prevents collisions and reduces retransmissions, thereby reducing access delay while maintaining procedural simplicity
Solution Approach 2:
The patent introduces an intermediary channel detection mechanism between the user equipment and the random access process. This intermediary step provides channel status information that guides the random access procedure, reducing delays caused by collisions without significantly complicating the overall access process
Data Source
AI summary
The present disclosure provides a preamble configuration method on an unlicensed carrier, which includes: PRACH configuration information. The PRACH configuration information includes sub-frame location information, CCA interval location information for a channel idle estimation, a channel detection mechanism, preamble format information and preamble sending location information; the sub-frame location information representing a sub-frame number of a sub-frame in which a preamble to be sent is located, the CCA interval location information representing a location on the sub-frame or on a previous sub-frame of the sub-frame, the CCA interval occupying at most N symbols at a head or at an end of the sub-frame, the preamble format information representing that the preamble is a format 0 preamble, the preamble sending location information representing a sending location of the format 0 preamble to be sent on the sub-frame. Control signaling carrying the PRACH configuration information to user equipment is sent.