Random Access Method Using Preamble Mapping to Reduce Delay
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Solution Overview
Problem
The existing random access method in wireless communications networks experiences channel resource waste and access delay due to the retransmission of scheduling signaling on the PDCCH channel during the random access process.
Innovation Solution
The method involves acquiring and using pre-obtained mapping relationships between downlink assignment information and preambles to determine the necessary assignment information for random access response messages, eliminating the need for PDCCH channel retransmission by directly sending the random access response message based on the obtained information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station retransmits scheduling signaling of the random access response message on the PDCCH channel, then the UE can reliably receive the random access response message, but channel resources are wasted and access delay increases
Solution Approach 1:
The base station pre-obtains and determines the downlink assignment information for the random access response message before actual transmission. This preliminary determination eliminates the need for subsequent PDCCH retransmissions, as the UE can directly use the pre-determined information to receive the message, thereby reducing access delay while maintaining reliability
Solution Approach 2:
The patent extracts the downlink assignment information from the PDCCH scheduling signaling and determines it directly through pre-obtained mapping relationships. By taking out this critical information and determining it independently, the system eliminates the harmful retransmission loop on the PDCCH channel while preserving the necessary scheduling information for reliable message reception
2Reliability
If the base station retransmits scheduling signaling on the PDCCH channel, then the random access response message can be delivered, but channel resources are wasted
Solution Approach 1:
The base station performs preliminary determination of downlink assignment information before transmission, using pre-obtained mapping relationships between preambles and downlink assignment information. This advance preparation eliminates the need for energy-consuming PDCCH retransmissions while ensuring the UE can reliably receive the random access response message with the pre-determined assignment information
Solution Approach 2:
The system uses the pre-obtained mapping relationship stored in both base station and UE to self-determine the downlink assignment information without requiring additional PDCCH signaling. This self-service mechanism eliminates redundant channel usage and energy waste while maintaining reliable message delivery
Data Source
AI summary
Embodiments of the present invention disclose a random access method and an apparatus. According to the random access method disclosed in the embodiments, first downlink assignment information is obtained in a manner of a mapping relationship between first downlink assignment information and a preamble, where the first downlink assignment information is downlink assignment information used by a random access response message, and scheduling signaling of the random access response message does not need to be retransmitted by using the PDCCH channel, thereby resolving problems of a channel resource waste and an access delay in an existing random access method. The problems are caused because the PDCCH channel is used to retransmit the scheduling signaling of the random access response message.