Random Access Timing Advance for Msg3 Interference Reduction
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Solution Overview
Problem
In the random access mechanism, the network device fails to correctly receive messages (Msg3) from terminal devices due to interference, as different devices send their messages at the same time, leading to access failures.
Innovation Solution
The network device sends timing advances to stagger the time windows for message transmission by different terminal devices, ensuring minimal overlap or no overlap between these windows, thereby reducing interference and improving access success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If different terminal devices send Msg3 according to the same slot (n+X) mechanism, then the access procedure is simple and standardized, but interference exists between Msg3s from different terminal devices causing access failure
Solution Approach 1:
The patent applies local quality by assigning different timing advance values to different terminal devices based on their specific characteristics (such as round-trip time estimation). Each terminal device receives a customized timing advance value in its RAR message, allowing individual optimization of message transmission timing while maintaining the overall standardized random access procedure. This resolves the contradiction by enabling differentiated timing control without complicating the general access mechanism.
2Measurement precision
If the network device waits to receive random access preamble before sending RAR message, then uplink synchronization can be estimated, but the terminal device cannot complete uplink synchronization when sending Msg3
Solution Approach 1:
The patent applies preliminary action by including the timing advance value in the RAR message before the terminal device sends Msg3. This allows the terminal device to perform uplink synchronization adjustment in advance, based on the timing advance information received from the network device. The terminal device can then send Msg3 with proper timing alignment, resolving the contradiction between having time to estimate round-trip time and completing uplink synchronization before Msg3 transmission.
3Productivity
If the network device sends RAR messages to multiple terminal devices simultaneously, then access capacity increases, but interference between different terminal devices' messages increases
Solution Approach 1:
The patent applies segmentation by dividing the message transmission process into different time windows for different terminal devices. Each terminal device is assigned a specific time window based on its timing advance value, which segments the overall transmission process into non-overlapping (or minimally overlapping) intervals. This allows the network device to send RAR messages to multiple terminal devices simultaneously while preventing interference between their Msg3 transmissions, thus resolving the contradiction between access capacity and message interference.
Data Source
AI summary
This application relates to the field of communication technologies, and provides a communication method and apparatus. In the method, before receiving a random access preamble from a terminal device, a network device sends a random access response message to the terminal device. For different terminal devices, the network device may respectively indicate different timing advances by using different random access response messages, to stagger time at which the different terminal devices send messages (for example, Msg3) to the network device. This reduces mutual interference between the messages sent by the different terminal devices, and reduces a probability that the network device fails to receive the message of the terminal device, to help improve an access success rate of the terminal device.