Random Access Preamble Power Offset for Low-Latency PUSCH Access
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Solution Overview
Problem
The existing random access procedure in communication protocols like LTE and future 5G is inefficient and complex, particularly in scenarios requiring low delay, high reliability, and large-scale terminal access, with valuable access resources being preempted.
Innovation Solution
A method where a terminal sends a random access preamble and a physical uplink shared channel (PUSCH) at different transmit powers, indicating a power deviation to the base station, allowing the base station to associate and demodulate the preamble with the PUSCH, thereby optimizing radio resource utilization and reducing access delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a conventional four-step contention-based random access procedure is used, then the access process is standardized and compatible, but the access delay increases and resource utilization decreases
Solution Approach 1:
The patent combines the random access preamble transmission and uplink data transmission into a single uplink slot, merging two separate transmission operations. This reduces the number of steps from four to two, directly decreasing access delay while maintaining standardized compatibility through the use of existing physical channels (PRACH and PUSCH).
Solution Approach 2:
The patent performs preliminary power deviation indication by including power deviation information in the uplink data transmission. This allows the base station to pre-calculate and store the power deviation between the random access preamble and uplink data before demodulation is needed, streamlining the demodulation process and reducing overall access time.
2Reliability
If separate demodulation reference signals are used for random access preamble and uplink data, then demodulation accuracy is ensured, but radio resource utilization decreases
Solution Approach 1:
The patent makes the random access preamble serve multiple functions: it acts as both the random access signal for contention resolution and as the demodulation reference signal for the uplink data transmission. This multi-functionality eliminates the need for separate demodulation reference signals, saving radio resources while maintaining demodulation accuracy through the use of power deviation indication.
Solution Approach 2:
The patent changes the power parameter by indicating the power deviation between the random access preamble and uplink data. This parameter change allows the base station to correctly demodulate the uplink data using the random access preamble as reference, ensuring demodulation accuracy without requiring additional reference signals.
3Productivity
If random access resources are frequently occupied for data transmission, then resource utilization improves, but access reliability may be compromised
Solution Approach 1:
The patent implements feedback by indicating power deviation information from the terminal to the base station. This feedback mechanism ensures that the base station has accurate power information for demodulating uplink data that shares resources with random access preambles, maintaining access reliability even when resources are frequently occupied for data transmission.
Data Source
AI summary
This application provides a transmission method and apparatus. The method includes: A terminal sends a random access preamble to a base station at a first transmit power, and sends a PUSCH to the base station at a second transmit power, where power deviation between the first transmit power and the second transmit power is indicated to the base station by indication information; and the terminal receives a random access response or a contention resolution message from the base station. Implementing this application can improve an existing random access procedure, so that the random access procedure is adapted to scenario requirements such as low delay, high reliability, and large-scale terminal access.