Combined Spreading Codes for Mobile User Capacity
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Solution Overview
Problem
In overloaded mobile communication systems, the limited number of orthogonal spreading codes restricts the ability to distinguish between colliding data packets, leading to increased collisions and decoding challenges at the base station.
Innovation Solution
The implementation of combined spreading codes, which are formed by series connections of orthogonal spreading codes, allows for the use of a larger number of unique spreading codes, enabling effective detection and recovery of colliding data packets by incorporating redundancy units within the data transmission units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If orthogonal spreading codes are used for user distinction, then user identification accuracy is improved, but the number of accessible users is limited due to code scarcity
Solution Approach 1:
The patent segments the limited orthogonal spreading codes into multiple groups, where each group contains several codes. Instead of assigning entire groups to individual users, the system allows users to dynamically select and combine codes from different groups, effectively multiplying the number of available code combinations beyond the original limited set.
Solution Approach 2:
The patent introduces a new dimension of code combination by allowing users to select codes across multiple groups rather than being confined to a single code assignment. This dimensional expansion transforms the code selection space from a one-to-one mapping to a combinatorial selection process, dramatically increasing user capacity.
2Quantity of substance
If more users share the same time frequency resources, then system capacity is improved, but collision probability increases
Solution Approach 1:
The patent performs preliminary organization of orthogonal spreading codes into multiple groups before user access. This pre-arranged structure enables the system to manage and track code assignments more effectively, reducing random collisions by ensuring that code selection follows a structured pattern rather than purely random assignment.
Solution Approach 2:
The patent changes the parameter of code assignment from static single-code allocation to dynamic multi-code combination. Users can select different combinations of codes from multiple groups, transforming the code assignment parameter space and reducing collision probability through increased combinatorial diversity.
3Quantity of substance
If combined spreading codes are used to increase user capacity, then number of accessible users is improved, but code management complexity increases
Solution Approach 1:
The patent segments the code management task into two parts: the base station manages the grouping structure and overall assignment, while user equipment handles the specific code selection and combination. This segmentation distributes management complexity and makes the overall system more manageable despite the increased user capacity.
Solution Approach 2:
The patent implements partial code combination where users select codes from multiple groups but not all possible combinations are required to be managed simultaneously. This partial action approach increases user capacity while keeping the immediate management complexity at each node manageable.
Data Source
AI summary
Embodiments of the present application disclose a spreading method, a spreading control method, and apparatuses thereof. The spreading method comprises: determining a first combined spreading code to be used at least according to first information associated with spreading by using combined spreading codes, the first combined spreading code comprising N spreading codes, and N being an integer not less than 2; and spreading N data units by using the first combined spreading code, wherein the N data units comprise at least one first unit and at least one second unit, the at least one first unit comprises data to be sent, and the at least one second unit is configured to recover the at least one first unit. The methods and apparatuses of the embodiments of the present application can effectively solve the problem of an insufficient number of orthogonal spreading codes by using combined spreading codes.