Variable Hopping Distance Resource Allocation for Inter-Cell Interference Randomization
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Solution Overview
Problem
In E-UTRAN systems, frequency-selective scheduling is hindered by large fluctuations in Signal to Interference Ratio due to unknown inter-cell co-channel interference, leading to degraded bandwidth efficiency and cell performance, especially in high mobility scenarios and real-time services, with existing frequency hopping schemes not considering system-level performance and using constant hopping distances that fail to randomize inter-cell interference.
Innovation Solution
A method for allocating mobile user resources using a random frequency hopping pattern with variable hopping distances among UEs in the same cell, generated by a mapping sequence that randomizes resource allocation and interference, ensuring unique resource pairs and avoiding overlap between neighboring cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency-selective scheduling is applied to exploit channel condition, then bandwidth efficiency is improved, but large fluctuation of SIR occurs due to lacking knowledge of instant inter-cell co-channel interference
Solution Approach 1:
The patent applies dynamics by making the hopping distance variable rather than constant. The hopping distance is dynamically adjusted based on the cyclic shift value, which changes with resource allocation. This dynamic approach allows the system to adapt to varying interference conditions while maintaining frequency diversity gain, thereby improving SIR stability without sacrificing bandwidth efficiency.
Solution Approach 2:
The patent changes the parameter of hopping distance from a fixed constant to a variable that depends on the cyclic shift value. This parameter change enables the frequency hopping pattern to vary according to different resource allocations and interference scenarios, allowing the system to optimize both bandwidth efficiency and SIR stability by adapting to real-time channel conditions.
2Reliability
If frequency-selective scheduling allocates more bandwidth to cell-edge users in severe inter-cell interference, then cell edge performance is improved, but bandwidth efficiency degrades
Solution Approach 1:
The dynamic hopping distance adapts to the specific resource allocation scenario. For cell-edge users experiencing severe interference, the variable hopping pattern provides better frequency diversity by jumping to less interfered frequency resources, improving their performance without requiring excessive bandwidth allocation. This dynamic adaptation maintains overall system bandwidth efficiency.
Solution Approach 2:
The patent applies local quality by making the hopping distance specific to each user's resource allocation context. Different users experience different hopping distances based on their cyclic shift values and resource block assignments. This localized approach allows cell-edge users to receive tailored frequency hopping patterns that optimize their individual performance while maintaining efficient overall bandwidth utilization.
3Device complexity
If constant frequency hopping distance is used, then implementation is simple, but inter-cell interference is not randomized effectively
Solution Approach 1:
The patent changes the hopping distance parameter from a system-wide constant to a user-specific variable derived from the cyclic shift value. This parameter transformation maintains implementation simplicity because the hopping distance is directly calculated from existing allocation parameters, while effectively randomizing inter-cell interference by ensuring different users have different hopping patterns.
Solution Approach 2:
The patent applies local quality by making the hopping distance specific to each user's local resource allocation context rather than a global constant. Each user's hopping distance is locally determined by their cyclic shift value and resource block assignment, which naturally randomizes inter-cell interference across different cells and users while keeping the overall system complexity manageable.
Data Source
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AI summary
Disclosed is a method for allocating mobile user resource, which comprises the steps of: randomly generating a resource allocation mapping sequence by a base station based on a hopping scheme, which has a variable hopping distance; and allocating communication resource by the base station to each UE within a cell, where the base station is present, based on the generated resource allocation mapping sequence. Since the hopping scheme is generated randomly, the resource allocation scheme according to the present invention may randomize a resource allocation procedure among different cells, thereby randomizing the inter-cell interference and decreasing dramatic changes of interference due to the user's movement.