Random Access Preamble ZCZ Selection for Uplink Synchronization
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Solution Overview
Problem
Current mobile communication systems face challenges in selecting an appropriate set of Random Access Preamble (RAP) lengths that balance autocorrelation and cross-correlation properties, leading to interference issues due to uncertainty in round trip time and varying cell radii, without a feasible scheme for minimizing signaling overload.
Innovation Solution
A method and apparatus for selecting and transmitting random access preambles with Zero Correlation Zones (ZCZ) of specific lengths, using cyclic shift increments from a predefined set {0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419} to ensure effective uplink synchronization and reduce signaling overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple values of cyclic shift increments (NCS) are used to handle varying cell radii, then uplink synchronization is improved, but signaling overload increases
Solution Approach 1:
The patent changes the parameter of cyclic shift increment (NCS) from multiple values to a single value configuration. By modifying how NCS is selected and applied across different cell radii, the system achieves uplink synchronization without requiring multiple NCS values to be signaled, thus reducing signaling overload while maintaining synchronization reliability.
Solution Approach 2:
The patent makes a single NCS value serve multiple functions across different cell radii. Instead of having dedicated NCS values for different cell sizes, one NCS configuration is designed to universally handle synchronization across varying cell radii, eliminating the need for multiple signaling options and reducing overall signaling overhead.
2Adaptability or versatility
If the number of preambles is increased to cover more cell radii, then adaptability to different cell sizes is improved, but the number of required root sequences increases
Solution Approach 1:
The patent changes the approach from increasing the number of preambles to optimizing the configuration of existing preambles. By adjusting parameters such as cyclic shift increments and zero correlation zone lengths, the system achieves broader cell radius coverage without proportionally increasing the number of root sequences required.
Solution Approach 2:
The patent introduces dynamic configuration of preamble parameters including zero correlation zone lengths and cyclic shift increments. This dynamic approach allows the same set of root sequences to adapt to different cell radii through parameter adjustment rather than requiring separate preamble sets for each cell size, thereby reducing the total number of root sequences needed.
Data Source
AI summary
Method and apparatus are provided for transmitting a random access preamble in a mobile communication system. The preamble is selected from a set of random access preambles provided with Zero Correlation Zones of length NCS−1, where NCS is a cyclic shift increment selected from a set of cyclic shift increments {0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419}, and transmitted.