Link Adaptation via Interference Adjustment Factor
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Solution Overview
Problem
Traditional wireless communication systems, such as LTE networks, fail to adapt modulation and coding schemes (MCS) to interference from adjacent cells at a resource block (RB) granularity, leading to inaccurate SINR representation and insufficient link adaptation.
Innovation Solution
A fine-grained link adaptation mechanism that determines an effective SINR for individual receivers at the RB level by accounting for inter-cell interference using an interference adjustment factor, in addition to channel state information and packet retransmission data, allowing for precise MCS adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional link adaptation mechanisms are used, then the system is simple to implement, but the SINR representation is inaccurate and link adaptation is insufficient
Solution Approach 1:
The patent segments the link adaptation process by introducing an interference adjustment factor that operates independently from the traditional CQI-based SINR determination. This factor is calculated separately based on inter-cell interference measurements and then applied to adjust the effective SINR, allowing the system to maintain the existing simple CQI reporting mechanism while adding precise interference compensation without complete system redesign
Solution Approach 2:
The patent applies local quality by introducing cell-specific interference adjustment factors that are tailored to each cell's interference environment. Each cell can determine its own interference adjustment factor based on local interference measurements from neighboring cells, allowing precise local adaptation while maintaining overall system compatibility with existing LTE infrastructure
2Reliability
If interference adjustment factor is introduced, then link adaptation accuracy improves, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by having the base station pre-calculate the interference adjustment factor based on interference measurements from neighboring cells before determining the MCS. This pre-computed factor is then used to adjust the effective SINR, ensuring that interference compensation is already in place before the actual link adaptation decision is made, improving reliability without adding complexity during the critical MCS selection moment
Solution Approach 2:
The interference adjustment factor serves as an intermediary element that bridges the gap between traditional CQI-based link adaptation and interference-aware adaptation. It mediates between the simple existing CQI reporting mechanism and the need for precise interference compensation, allowing the system to incorporate interference information without completely redesigning the MCS determination process
3Reliability
If RB-level interference accounting is implemented, then data transmission reliability improves, but network redesign requirements increase
Solution Approach 1:
The patent segments the interference management approach by applying interference adjustment factors at the resource block level for MCS determination. Each RB can have its own interference adjustment factor calculated based on inter-cell interference measurements, enabling fine-grained link adaptation at RB level while maintaining compatibility with existing LTE resource allocation and scheduling mechanisms
Solution Approach 2:
The patent introduces dynamics by making the interference adjustment factor adaptable and updateable without requiring fixed network redesign. The factor can be dynamically calculated based on current interference conditions and updated as network conditions change, allowing the system to adapt to varying interference environments while maintaining ease of implementation through existing LTE dynamic scheduling capabilities
Data Source
AI summary
The present disclosure provides a fine-grained link adaptation mechanism that allows for link adaptation at a resource block granularity. To this end, the fine-grained link adaptation mechanism can determine the effective signal-to-interference-plus-noise ratio for individual user equipment in a particular cell at the resource block granularity. This way, the transmitter can use the effective signal-to-interference-plus-noise ratio to adapt the modulation and coding scheme at the resource block granularity. The fine-grained link adaptation mechanism can be introduced to a long term evolution (LTE) network without substantial redesign of the LTE network.