Random Access Response With Multiple TC-RNTIs For Collision Reduction
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Solution Overview
Problem
In mobile communications systems, the contention-based random access procedure leads to high average access delays due to collisions among terminal side devices, resulting in low random access success rates, especially in satellite communications where unidirectional transmission delays exceed 100 milliseconds.
Innovation Solution
The proposed solution involves a random access method where the network side device sends a random access response (RAR) with multiple temporary cell radio network temporary identifiers (TC-RNTIs), allowing multiple terminal side devices to initiate random access simultaneously, and the terminal side device selects a unique TC-RNTI to generate a demodulation reference signal, reducing the likelihood of collisions and increasing access success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal side device randomly selects a random access preamble from a random access preamble set and sends it to initiate a random access procedure, then the random access procedure can be initiated, but when multiple terminal side devices simultaneously initiate random access procedures, only one terminal side device is allowed access while others are ignored, resulting in low random access success rate and long average access delay
Solution Approach 1:
The patent segments the random access response by including multiple temporary cell radio network temporary identifiers (TC-RNTIs) in the RAR message. Each TC-RNTI corresponds to a different terminal side device, allowing the network side device to separately identify and serve multiple accessing devices simultaneously. This segmentation resolves the collision problem by dividing the shared random access resource into distinct identifiable paths for each device.
2Productivity
If the network side device allows only one terminal side device to access at a time in contention-based random access, then collision is avoided for the selected device, but other terminal side devices experience repeated access failures and extended delays
Solution Approach 1:
The patent applies preliminary action by pre-allocating multiple temporary cell radio network temporary identifiers (TC-RNTIs) in the random access response before the terminal side devices complete their access procedures. This allows the network side device to prepare multiple access paths in advance, enabling simultaneous acceptance of multiple terminal side devices without waiting for sequential processing, thereby improving overall network access efficiency.
3Adaptability or versatility
If multiple terminal side devices use the same random access preamble simultaneously, then the random access procedure can be initiated by multiple devices, but the network side device can only process one device at a time causing collisions for other devices
Solution Approach 1:
The patent uses temporary cell radio network temporary identifiers (TC-RNTIs) as intermediaries to mediate between multiple terminal side devices using the same random access preamble and the network side device. Each TC-RNTI acts as a unique identifier that allows the network side device to distinguish between different devices, enabling simultaneous processing of multiple access requests without collision while maintaining the flexibility of shared preamble usage.
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AI summary
A random access method and apparatus are provided. The method includes: sending, by a first terminal side device, a random access preamble to a network side device; receiving, by the first terminal side device, a random access response RAR corresponding to the random access preamble, where the RAR includes P temporary cell radio network temporary identifiers TC-RNTIs, and P is an integer greater than 1; and sending, by the first terminal side device to the network side device based on the RAR, a first message and a demodulation reference signal used to demodulate the first message, where the demodulation reference signal is generated based on the first TC-RNTI, and the first TC-RNTI is one of the P TC-RNTIs.