Cooperative IR Group for Cell Edge Interference
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Solution Overview
Problem
In wireless communication access networks, user performance is limited by interference from neighboring cells, particularly for users at the cell edge, where the Carrier-to-Interference and Noise Ratio (CINR) is often 0 dB or below, hindering effective data transmission.
Innovation Solution
The implementation of a cooperative transmission scheme where neighboring cells form a transmit incremental redundancy (IR) group with the serving cell to enhance data transmission to users experiencing high interference, using a combination of turbo encoding and circular buffer mechanisms to improve decoding at a lower coding rate and increase coding gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-cell transmission is used, then device complexity is low, but user performance deteriorates due to high interference from neighboring cells
Solution Approach 1:
Multiple neighboring cells are merged into a cooperative transmission group that jointly serves cell edge users. The cells coordinate their transmissions to provide incremental redundancy, transforming individual interfering sources into a cooperative system that improves user performance while managing interference through coordinated resource allocation.
2Reliability
If incremental redundancy with multiple cells is implemented, then coding gain increases, but device complexity increases due to coordinated transmission requirements
Solution Approach 1:
The transmission of coded bits is segmented across multiple cells, with each cell transmitting a portion of the redundant bits. This segmentation allows the system to achieve incremental redundancy and coding gain while distributing the computational complexity across multiple base stations rather than requiring one complex centralized system.
Solution Approach 2:
The coded bits are pre-processed and divided into segments before transmission. Each cell is pre-configured with its designated portion of the redundant bits, allowing coordinated incremental redundancy transmission without requiring complex real-time coordination during the actual transmission phase.
3Reliability
If higher coding rate is used to overcome interference, then data transmission reliability improves, but transmission efficiency decreases
Solution Approach 1:
The coding rate is dynamically adjusted based on the user's channel conditions and interference level. Cell edge users receive transmissions with higher redundancy and lower initial coding rates, while users with better channel conditions receive transmissions with lower redundancy and higher coding rates, optimizing both reliability and transmission efficiency for different user scenarios.
Data Source
AI summary
Embodiments enable cooperative transmissions from a group of cells (can include the serving cell and one or more neighboring cells) to a user equipment (UE). The cooperative transmissions emulate Hybrid Automatic Repeat Request (HARQ) transmissions to the UE. Specifically, when the UE is experiencing high interference, the UE's serving cell can create a transmit incremental redundancy (IR) group for the UE, which is used to transmit information in a HARQ-like fashion to the UE. Because interference is reduced, the UE can decode the information at a lower coding rate and higher coding gain.