Dynamic Code Allocation in Space Division Radiocommunication Systems
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Solution Overview
Problem
In mobile radio communication systems, existing code allocation schemes are inadequate for dynamic environments with mobile terminals, leading to increased complexity and reduced availability of orthogonal variable spreading factor (OVSF) codes, as they fail to account for terminal mobility and interference.
Innovation Solution
A method for dynamically allocating communication codes in a space division multiple access system that considers the send/receive parameters of mobile terminals, allowing nonorthogonal code reuse based on azimuth discrepancy and other criteria like terminal movement and interference levels, without partitioning codes by predefined sectorization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If codes are partitioned by predefined sectorization for fixed terminals, then code allocation is simplified and interference is reduced, but code availability decreases and complexity increases for mobile terminals
Solution Approach 1:
The patent applies dynamics by transitioning from static sector-based code partitioning to dynamic code allocation based on real-time terminal position and movement. The system continuously monitors terminal mobility and adjusts code assignment accordingly, allowing the same code to be reused for different terminals at different times and locations, thereby increasing code availability while maintaining interference management through adaptive decision-making.
Solution Approach 2:
The patent changes the allocation parameters from fixed geographical sectors to dynamic parameters including terminal position, movement status, and interference conditions. By evaluating these changing parameters in real-time, the system determines whether non-orthogonal code reuse is acceptable, thus adapting the code allocation strategy to current system conditions rather than relying on predetermined sector partitions.
2Reliability
If orthogonal codes are strictly allocated to all terminals, then interference between channels is minimized, but code availability and system capacity are reduced
Solution Approach 1:
The patent applies partial action by selectively applying orthogonal code allocation only when necessary based on terminal mobility and interference conditions. For stationary or slowly moving terminals where interference risk is low, the system permits non-orthogonal code reuse, thus partially relaxing the strict orthogonality requirement to increase code availability while maintaining adequate interference management for critical cases.
Solution Approach 2:
The system dynamically changes the orthogonality parameter based on terminal movement status and spatial separation. When terminals are sufficiently separated or stationary, the system allows non-orthogonal codes; when terminals are moving or closely positioned, the system enforces orthogonal code allocation. This parameter adaptation enables flexible trade-off between interference management and code availability.
3Quantity of substance
If code allocation adapts to terminal mobility dynamically, then code reuse increases and availability improves, but system complexity and processing requirements increase
Solution Approach 1:
The patent segments the code allocation decision process into distinct evaluation stages: terminal position determination, movement status assessment, interference condition evaluation, and final code selection. This segmentation allows the complex allocation process to be broken down into manageable components, each handling a specific aspect of the decision-making, thus reducing overall system complexity while enabling dynamic adaptation.
Solution Approach 2:
The system implements feedback mechanisms by continuously monitoring terminal position and movement status, using this information to adjust code allocation decisions in real-time. The feedback loop enables the system to adapt to changing conditions without requiring complete re-allocation, thus managing complexity through iterative refinement rather than exhaustive re-evaluation of all parameters.
Data Source
AI summary
Method of allocating communication codes to channels set up in respect of mobile terminals in communication in a cell of a radiocommunication system, in which the cell is served by a fixed station having means of adjustment of send/receive parameters defining a respective antenna pattern in respect of each mobile terminal in the cell, in which the allocated communication codes form part of a set of codes some at least of which are mutually orthogonal. In response to channel setup or reconfiguration request in respect of a first mobile terminal in the cell, the allocation to the said channel of a code nonorthogonal to at least one code of the set already allocated to another channel set up in respect of a second mobile terminal in the cell is conditionally admitted, as a function of a comparison between the send/receive parameters determined in respect of the first and second terminals.