Random Access Timing Calculation for Mixed Numerology Networks
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Solution Overview
Problem
In communications networks, especially with high carrier frequencies and mixed numerologies, terminal devices face challenges in efficiently determining the timing for random access procedures due to beamforming and varying symbol durations, leading to increased signaling overhead and difficulty in finding the RACH occasion.
Innovation Solution
A method where a terminal device decodes a time index from received system information with a first symbol duration, determines a second symbol duration, and calculates a second time instant based on the time index and receiver parameters to transmit a random access preamble, minimizing the number of bits needed for signaling and allowing efficient random access in networks with mixed numerologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If beamforming is used to support high carrier frequencies, then network reach and signal concentration are improved, but timing synchronization and random access procedure complexity increase due to varying symbol durations
Solution Approach 1:
The network node transmits system information including a time index and symbol duration information before the random access procedure. This preliminary transmission allows the terminal device to pre-calculate the second time instant and determine the correct RACH occasion timing, avoiding timing conflicts that would otherwise require complex real-time synchronization adjustments.
Solution Approach 2:
A time index serves as an intermediary parameter between the network node's transmitted system information and the terminal device's random access timing. The time index, combined with symbol duration information, enables the terminal device to calculate the precise second time instant for RACH transmission without requiring complex direct timing coordination with the network node.
2Adaptability or versatility
If system information is transmitted with varying symbol durations to support mixed numerologies, then network adaptability is improved, but the difficulty of determining RACH occasion timing increases
Solution Approach 1:
The system information transmission is segmented into distinct parameters: a time index indicating the position within a synchronization burst set, and explicit symbol duration information. This segmentation allows the terminal device to process each parameter independently and combine them to determine the second time instant, simplifying timing determination in mixed numerology environments.
Solution Approach 2:
The patent changes the parameter representation by introducing a time index and explicit symbol duration information in the system information. Instead of requiring the terminal device to infer timing from complex frame structures, the parameters are explicitly provided, allowing straightforward calculation of the RACH occasion timing regardless of the underlying numerology configuration.
3Ease of operation
If explicit timing information is transmitted for each RACH occasion to simplify terminal device timing determination, then ease of operation is improved, but signaling overhead increases
Solution Approach 1:
The system information transmission serves multiple functions: it provides the time index for RACH occasion identification, conveys symbol duration information for timing calculation, and supports mixed numerology configurations. This multi-functionality reduces the need for separate dedicated timing indication messages, thereby reducing overall signaling overhead while maintaining ease of timing determination.
Solution Approach 2:
The terminal device performs self-service by autonomously calculating the second time instant using the time index and symbol duration information received in the system information. This eliminates the need for the network node to explicitly signal each RACH occasion timing, significantly reducing signaling overhead while maintaining timing accuracy.
4Quantity of substance
If the number of bits for time index signaling is minimized, then signaling efficiency is improved, but the precision of timing alignment may be compromised
Solution Approach 1:
The patent resolves the bit precision trade-off by moving from a single-dimensional time index to a two-dimensional parameter space: the time index indicates the position within a synchronization burst set, while the symbol duration information provides the temporal scaling. This dimensional expansion allows accurate timing alignment to be achieved with fewer bits in the time index itself.
Data Source
AI summary
There is provided mechanisms for performing random access in a network. A method is performed by a terminal device and a method is performed by a network node. The terminal device method comprises decoding a time index from received system information. The system information is transmitted with a first symbol duration from a network node and is received by the terminal device at a first time instant. The method comprises determining a second symbol duration from the system information. The method comprises determining a second time instant, in relation to the first time instant, based on the time index, the second symbol duration, and a first receiver parameter. The method comprises transmitting a random access preamble at the second time instant.