Alternating MBSFN Sub-Frame Configuration for Interference Reduction
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Solution Overview
Problem
In LTE and LTE-A systems, the use of MBSFN sub-frames for energy saving leads to increased interference and reduced spectrum efficiency when all neighboring cells employ this configuration, as it centralizes service sub-frame resources, thereby affecting edge cell performance.
Innovation Solution
A method where a network node configures a serviceless MBSFN sub-frame for an energy-saving cell and alternates this configuration with neighboring cells, reducing interference by coordinating the MBSFN sub-frame configurations between cells using information exchange through interfaces like X2, S1, M2, or itf-N, and adjusting based on interference thresholds or high-interference indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If all neighboring cells configure serviceless MBSFN sub-frames to save energy, then energy consumption is reduced, but interference at cell edges increases and spectrum efficiency decreases
Solution Approach 1:
The patent implements periodic action by configuring MBSFN sub-frames in an alternating pattern across different cells. Specifically, in a first cell, MBSFN sub-frames are configured in first time periods, while in a second neighboring cell, MBSFN sub-frames are configured in second time periods that do not overlap with the first time periods. This periodic staggering ensures that not all cells simultaneously activate energy-saving mode in the same time slot, thereby reducing cumulative interference at cell edges while maintaining energy savings benefits.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the time period parameters for MBSFN sub-frame configuration. The network node modifies the timing parameters (first time periods vs. second time periods) to create a temporal offset between neighboring cells. This parameter adjustment allows the system to switch between energy-saving mode and interference-reduction mode based on detected interference levels, optimizing both energy consumption and interference management.
2Use of energy by stationary object
If MBSFN sub-frames are used to reduce transmission time and save power, then energy savings are achieved, but service sub-frame resources become centralized
Solution Approach 1:
The patent resolves the resource centralization issue through periodic action by distributing MBSFN sub-frame configurations across multiple time periods in neighboring cells. Instead of all cells simultaneously consolidating resources in the same time slot, the system staggers these consolidations temporally. This ensures that while resources appear centralized in any given time period, the overall distribution across time and space remains balanced, preventing excessive resource concentration.
3Loss of time
If serviceless MBSFN sub-frames are configured to reduce Common Reference Signals, then transmission time is reduced, but spectrum efficiency decreases when all neighboring cells adopt this configuration
Solution Approach 1:
The patent addresses the spectrum efficiency problem through periodic action by implementing time-division multiplexing of MBSFN sub-frames across neighboring cells. In the first cell, serviceless MBSFN sub-frames are transmitted during first time periods with reduced CRS, while in the second neighboring cell, the same sub-frames are transmitted during non-overlapping second time periods. This periodic staggering ensures that spectrum resources are not simultaneously depleted across all cells, maintaining overall spectrum efficiency while still achieving transmission time reduction in each individual cell during its active period.
Data Source
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Figure 3
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AI summary
A method for configuring an energy-saving cell includes the following steps. A network node obtains information for configuring a serviceless Multicast Broadcast Single Frequency Network (MBSFN) sub-frame of an energy-saving cell; and the network node configures a serviceless MBSFN sub-frame of a neighboring cell of the energy-saving cell by alternating the serviceless MBSFN sub-frame of the neighboring cell with the serviceless MBSFN sub-frame of the energy-saving cell according to the information for configuring the serviceless MBSFN sub-frame of the energy-saving cell. In the method for configuring the energy-saving cell, the serviceless MBSFN sub-frame of the neighboring cell alternate with the serviceless MBSFN sub-frame of the energy-saving cell, thereby reducing interference between cells and improving stability of the system.