Random Access Response Decoding via Resource Indexing in 5G Terminals
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Solution Overview
Problem
In 5G communication systems, base stations face challenges in identifying and responding to different terminals that transmit the same random access preamble, leading to interference due to the same random access response being sent to all terminals.
Innovation Solution
Establishing a relationship between the random access preamble and response message, allowing for distinct responses to be transmitted to each terminal even when they send the same preamble, by using methods such as beam reciprocity, transmission beam information, and specific preamble IDs or RNTIs to differentiate between terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the base station transmits the same random access response to all terminals that transmitted the same preamble, then the base station can simplify its response mechanism, but interference occurs between different terminals receiving identical responses
Solution Approach 1:
The patent segments the random access response by associating it with specific time-frequency resources (RACH occasions) and beam identifiers. Each terminal receives a response tailored to its specific access occasion and beam, even when using the same preamble, thereby preventing interference while maintaining base station efficiency
Solution Approach 2:
The patent introduces additional dimensions for differentiation beyond the preamble itself - specifically time resources (RACH occasions), frequency resources, and beam identifiers. These dimensional additions allow the base station to distinguish between terminals and provide unique responses without increasing response mechanism complexity
2Loss of energy
If the base station transmits a single random access response for a given preamble, then transmission overhead is reduced, but collision probability increases when multiple terminals use the same preamble
Solution Approach 1:
The patent divides the random access response transmission into multiple segments based on time-frequency beam combinations. Each segment is associated with specific RACH occasions and beams, allowing the system to serve multiple terminals with the same preamble through different segments, thereby reducing collisions while minimizing overall transmission overhead
Solution Approach 2:
The patent introduces resource allocation information as an intermediary element that mediates between the base station's single response transmission and multiple terminals' needs. The resource allocation information directs each terminal to its specific time-frequency beam resources, reducing collision probability without requiring multiple full response transmissions
Data Source
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AI summary
The present disclosure relates to a communication technique for converging an IoT technology with a 5G communication system for supporting a higher data transmission rate beyond a 4G system, and a system therefor. The present disclosure may be applied to an intelligent service (for example, a smart home, a smart building, a smart city, a smart car or connected car, healthcare, digital education, retail business, a security and security related service, or the like) on the basis of a 5G communication technology and an IoT related technology. A method for a terminal according to the present disclosure comprises the steps of transmitting a random access preamble through a resource associated with a resource through which a downlink synchronization signal has been received; receiving a random access response message to the random access preamble; and decoding the random access response message by using information determined on the basis of the resource through which the downlink synchronization signal has been received.