Subframe-Level Cell State Control for Wireless Interference
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Solution Overview
Problem
In dense wireless networks with multiple small cells under a macrocell, interference among small cells limits effective user data throughput, and existing interference mitigation schemes cannot be applied at the subframe level due to backhaul delays, hindering the scaling of user data throughput with the number of small cells deployed.
Innovation Solution
Implementing a method to control the cell state of evolved Node B (eNB) and user equipment (UE) on a subframe basis, allowing for flexible scheduling and power management by determining and transmitting cell states across frames, enabling accurate UE measurements and reducing unnecessary power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of small cells are deployed under a macrocell to meet traffic demands, then network capacity and coverage are improved, but interference among small cells increases and effective user data throughput does not scale proportionally
Solution Approach 1:
The patent segments the cell operation into discrete subframe units, allowing independent control of transmission in each subframe. This segmentation enables selective activation/deactivation of small cells at subframe level, reducing interference while maintaining overall network capacity and throughput scaling.
Solution Approach 2:
The patent implements dynamic cell state control where small cells can switch between active and dormant states on a subframe-by-subframe basis. This dynamic adjustment allows the network to adapt to varying traffic conditions and minimize interference in real-time, enabling throughput to scale with the number of deployed small cells.
2Object-generated harmful factors
If interference mitigation schemes are implemented to reduce interference among small cells, then interference is reduced, but the schemes cannot be applied at subframe level due to backhaul delays of tens of milliseconds
Solution Approach 1:
The patent employs preliminary action by having the eNB determine and transmit cell state information for future subframes in advance. The eNB decides the cell state for upcoming subframes and communicates this information to UEs before those subframes occur, enabling UEs to prepare appropriate measurement and reception actions without requiring real-time backhaul coordination.
Solution Approach 2:
The eNB performs self-service by autonomously determining cell states for its own subframes and communicating this information to UEs. This self-determined cell state information allows the system to operate without requiring complex real-time coordination through the backhaul, effectively making the system self-sufficient despite backhaul delays.
3Loss of information
If cell state information is transmitted at frame level only, then signaling overhead is reduced, but UE measurement accuracy deteriorates because UEs cannot accurately determine cell states for specific subframes
Solution Approach 1:
The patent applies partial action by transmitting cell state information selectively - providing detailed subframe-level cell state information only when necessary for accurate UE measurements, while using frame-level information for other purposes. This balanced approach maintains measurement precision without incurring excessive signaling overhead.
Data Source
AI summary
A method for controlling a cell state corresponding to whether to transmit a signal, on a subframe basis by an evolved Node B (eNB) in a wireless communication system is provided. The method includes determining a cell state of at least one subframe included in each of an N-th frame and an (N−1)-th frame, and at the start of the N-th frame, transmitting to a user equipment (UE), information about cell states of all subframes belonging to the N-th frame and information about cell states of all subframes belonging to the (N−1)-th frame.