GSM LTE Spectrum Sharing via Interference Avoidance
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Solution Overview
Problem
The existing frequency spectrum sharing between GSM and LTE systems results in low utilization and poor smoothness, particularly due to co-channel interference and inefficient bandwidth allocation, which hinders seamless transition from GSM to LTE as user numbers decrease.
Innovation Solution
A method and system that allocate GSM frequency points to cells, avoiding interference with LTE fixed channels, user resource locations, and control channels by using Resource Blocks and Resource Element Groups, and optionally increasing PDCCH resources to mitigate interference, allowing for coordinated frequency spectrum sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If GSM system allocates frequency points to cells, then frequency spectrum utilization is improved, but co-channel interference with neighboring cells increases
Solution Approach 1:
The frequency spectrum is segmented into different resource blocks (RBs) and resource element groups (REGs), allowing fine-grained allocation of frequency points to GSM cells while avoiding interference with LTE cells. This segmentation enables precise control over which frequency points are assigned to which cell, resolving the contradiction between spectrum utilization and interference.
Solution Approach 2:
Different quality levels of frequency resources are assigned to different cells based on their interference characteristics. GSM cells are allocated frequency points that do not overlap with LTE cell frequency points, creating locally optimized allocations that maximize spectrum utilization while minimizing co-channel interference through spatial differentiation.
2Productivity
If GSM system transits to LTE system, then frequency spectrum utilization is improved, but transition smoothness deteriorates
Solution Approach 1:
The system performs preliminary actions by pre-configuring frequency point allocations for both GSM and LTE cells before actual traffic begins. This includes pre-establishing the mapping between GSM frequency points and LTE resource blocks, and pre-calculating interference avoidance patterns. Such preliminary setup enables smooth transition from GSM to LTE as user numbers decrease, maintaining stability during the migration process.
Solution Approach 2:
The frequency allocation system is made dynamic, allowing real-time adjustment of which frequency points are assigned to GSM cells versus LTE cells based on current traffic conditions. As user numbers decrease in GSM cells, the system dynamically reallocates frequency points to improve LTE spectrum utilization while maintaining transition smoothness through continuous optimization.
3Reliability
If LTE system increases PDCCH resources, then interference mitigation is improved, but device complexity increases
Solution Approach 1:
Instead of increasing PDCCH resources for all cells uniformly, the system applies partial action by only increasing PDCCH resources for LTE cells that experience significant interference from neighboring GSM cells. The eNodeB calculates interference levels and selectively allocates additional PDCCH resources only where needed, avoiding unnecessary complexity in cells that do not require enhanced interference mitigation.
Data Source
AI summary
The disclosure discloses a method for sharing a frequency spectrum between a GSM system and a LTE system. The method includes: avoiding fixed channels of the LTE system of a current cell when allocating frequency points of the GSM system to the current cell and a neighbor cell interfering with the current cell; frequency domain resources allocated to users and indicated by Physical Downlink Share Channels (PDSCHs) and Physical Uplink Share Channels (PUSCHs) of the LTE system are not located on same frequency resources with frequency points of the GSM system of the current cell and the neighbor cell interfering with the current cell.