Random Access Preamble Construction Using M-Sequence Multiplication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In mobile communication systems, the existing random access methods face challenges in supporting various services without collisions between terminals, particularly due to limitations in differentiating access service classes and managing preamble codes efficiently, leading to collisions and reduced system performance.
Innovation Solution
A random access apparatus and method that constructs a random access preamble by multiplying multiple M-sequences and a Hadamard sequence, allowing terminals to select appropriate sequences based on access purposes, thereby reducing collisions and enhancing service differentiation without increasing the number of preamble symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple terminals request random access simultaneously using limited signatures and slots, then the system can maintain simple access structure, but the probability of collision between terminals becomes very high
Solution Approach 1:
The patent segments the random access preamble into multiple independent components: M-sequences (first and second) and Hadamard sequences. Each component can be independently selected and combined, creating a segmented structure that increases the total number of distinguishable preambles from 16 to 256 or more, thereby reducing collision probability while maintaining structural simplicity
Solution Approach 2:
The patent adds dimensional expansion by introducing multiple M-sequences (beyond the traditional single M-sequence) combined with Hadamard sequences. This creates an additional dimension in the code space, transforming the limited 16-signature system into a multi-dimensional code space with significantly more available preambles, thus reducing collisions without increasing system complexity
2Device complexity
If the W-CDMA system uses 15 slots and 16 signatures for random access, then the system structure remains simple, but the capability to differentiate access service classes is limited
Solution Approach 1:
The patent segments the service differentiation capability across multiple code components: different M-sequences can be assigned to different service classes, and different Hadamard sequences can represent different priorities. This segmentation allows fine-grained service differentiation without requiring a complete restructuring of the access system
Solution Approach 2:
The patent changes the parameters of the random access preamble by introducing multiple M-sequences with different properties (lengths, periods, initial values) and combining them with Hadamard sequences. This parameter expansion enables the system to encode service class information and priority levels within the existing slot structure, enhancing adaptability without increasing system complexity
3Ease of operation
If terminals select the same M-sequence for random access, then the selection process is simple, but collision occurs and terminals must retry
Solution Approach 1:
The patent segments the M-sequence selection process into multiple independent choices: terminals select from multiple first M-sequences and multiple second M-sequences separately, then combine them with Hadamard sequences. This segmentation multiplies the available options while keeping each individual selection simple, thereby reducing collisions and improving access success rate
Solution Approach 2:
The patent adds dimensional expansion to the sequence selection process by introducing multiple M-sequences in different dimensions (different lengths, periods, initial values) and combining them with Hadamard sequences. This creates a multi-dimensional selection space that maintains ease of operation while significantly reducing collision probability through increased diversity
Data Source
AI summary
A random access apparatus for supporting a variety of access service classes includes a radio frequency (RF) transmitting/receiving unit for receiving a preamble introduction broadcasting signal from a base station and transmitting a random access preamble to the base station, an introduction broadcasting signal processing unit for extracting a random access usage relating to M-sequences and hadamard sequences from the received preamble introduction broadcasting signal, a selecting unit for selecting a plurality of M-sequences and a hadamard sequence corresponding to a random access purpose based on the extracted random access usage, and a preamble producing unit for generating the random access preamble using the selected plurality of M-sequences and the selected hadamard sequence.