RACH Signal Phase Pattern Vector for mmWave Collision Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In mmWave wireless communication systems, the random access procedure between user equipment and base stations is hindered by pathloss and potential RACH signal collisions, especially in areas with high frequency and dynamic transmission timing changes.
Innovation Solution
A method is introduced to improve the random access procedure by configuring a phase pattern vector set, allowing base stations to distinguish RACH signals from user equipment with different repetitive transmission counts without interference, using Hadamard or DFT-based phase pattern vectors to minimize implementation complexity and resolve collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repetitive transmission of RACH signals is performed to overcome pathloss, then connection stability is improved, but RACH signal collision between user equipments increases
Solution Approach 1:
The patent divides the RACH signal transmission into multiple repetitions with different phase pattern vectors. Each user equipment is assigned a specific phase pattern vector from a set of orthogonal vectors, allowing multiple UEs to transmit simultaneously without collision. The base station receives multiple replicated signals and uses the phase pattern information to identify and separate signals from different UEs, effectively segmenting the signal space to resolve collisions while maintaining connection stability through repetitive transmission.
2Reliability
If dynamic transmission timing adjustment is implemented to adapt to channel conditions, then access reliability is improved, but signal differentiation between user equipments becomes difficult
Solution Approach 1:
The patent pre-configures a set of orthogonal phase pattern vectors before the random access procedure. Each user equipment is assigned a specific phase pattern vector in advance, and this assignment is communicated to the base station. When UEs transmit their RACH signals with dynamic timing adjustments, the base station can still differentiate between them by detecting the pre-assigned phase pattern vectors, eliminating the need for complex real-time differentiation while maintaining access reliability through adaptive timing.
3Measurement precision
If phase pattern vector set configuration is introduced to resolve collisions, then RACH signal differentiation is improved, but implementation complexity increases
Solution Approach 1:
The patent changes the phase parameter of the RACH signal by introducing phase pattern vectors with specific phase rotations. Instead of modifying complex signal structures or requiring additional physical layers, the solution simply varies the phase parameter across repetitions according to pre-defined orthogonal patterns. This parameter-based approach enables precise signal differentiation while keeping implementation complexity low, as it leverages existing signal processing capabilities without requiring complex new hardware or algorithms.
Data Source
Figure 1~2(b)
Figure 3~4
Figure 5~6
AI summary
Provided is a method for performing random access, the method comprising: obtaining information associated with a phase pattern vector set and information associated with a sequence set to be used during a random access process; selecting one phase pattern vector corresponding to the number of repetitive transmissions of an RACH signal, among a plurality of phase pattern vectors included in the phase pattern vector set; transmitting, to a base station, an RACH signal during a time section corresponding to the number of repetitive transmissions of an RACH signal, at a predetermined transmission point in the entire time section corresponding to the maximum number of repetitive transmissions; and receiving, from the base station, an RACH response signal indicating an estimated sequence, an estimated phase pattern vector, and an estimated transmission point.