Block Spreading Code Allocation for High-Speed Users
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Solution Overview
Problem
In wireless cellular communication networks, high-speed users cause inter-user interference due to channel variations, leading to degraded signal detection performance in block spreading code systems, which are not effectively managed by existing technologies.
Innovation Solution
The method involves selecting a restricted subset of block spreading codes that are mirror symmetric and cause minimal interference, assigning these codes based on user velocities to minimize inter-user interference, and using coherent orthogonal structures for simultaneous transmission within the same frequency-time resource.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block spreading codes are assigned to high-speed users, then signal transmission capacity is improved, but inter-user interference increases due to channel variations
Solution Approach 1:
The patent applies local quality by selecting specific block spreading codes from the Hadamard matrix that are particularly suitable for high-speed users based on their channel variation characteristics. Instead of using all codes uniformly, the system identifies and assigns only those codes (e.g., codes with mirror symmetry property) that minimize interference for high-velocity users while maintaining capacity for other users.
Solution Approach 2:
The patent changes the parameter of code selection by introducing velocity-based code assignment. The system modifies which block spreading codes are assigned to users based on their velocity parameters, selecting codes from the Hadamard matrix that are optimized for high-speed conditions, thereby reducing inter-user interference while maintaining transmission capacity.
2Object-affected harmful factors
If a restricted subset of block spreading codes is selected for high-speed users, then inter-user interference is reduced, but code assignment complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-selecting and pre-organizing a restricted subset of block spreading codes from the Hadamard matrix that are suitable for high-speed users. This subset is identified and prepared in advance, containing codes with specific properties (such as mirror symmetry) that minimize interference. When high-speed users need code assignment, the system only needs to select from this pre-prepared subset rather than evaluating all possible codes.
Solution Approach 2:
The patent segments the complete set of block spreading codes from the Hadamard matrix into different subsets based on user velocity characteristics. One subset is designated for high-speed users with codes optimized for their channel conditions, while other codes remain available for low-speed users. This segmentation simplifies the assignment process by creating distinct code pools for different user types.
3Reliability
If mirror symmetric codes are used for high-speed users, then signal detection reliability is improved, but signaling overhead increases due to explicit code indication
Solution Approach 1:
The patent applies self-service by enabling high-speed users to autonomously select their own block spreading codes from the restricted subset based on pre-configured criteria. Users with high velocity can independently identify and use codes with mirror symmetry properties without requiring explicit assignment messages from the base station, thereby reducing signaling overhead while maintaining detection reliability.
Solution Approach 2:
The system performs preliminary configuration by broadcasting the restricted subset of suitable codes to all users in advance. High-speed users can then use this pre-provided information to self-select appropriate codes without needing real-time explicit assignment, reducing the signaling overhead while ensuring they use codes optimized for their velocity conditions.
Data Source
AI summary
A transmission of information from a secondary to a primary node occurs in a plurality of N logical time durations. The transmission from the secondary to primary node in a wireless network is obtained using a first and a second sequence. Embodiments of the present invention mitigate interference by restricting the choice of the first sequence. Thus, in an embodiment of the invention, the first sequence is selected from a set of M sequences wherein M is strictly less than N. In order to accommodate high-velocity users, the restricted set contains a pair of sequences whose element-wise product is mirror symmetric. A transmission component for K-th logical time duration is obtained from the entire second sequence and K-th element of the first sequence.