Macro Cell Control for Small Cell Energy in Overlapping HetNets
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Solution Overview
Problem
In wireless communication systems, especially in HetNet environments, fast-moving user equipment can cause inefficiencies and interference when small cells transition from sleep to active modes, leading to unnecessary energy consumption and interference, particularly when handovers to small cells are avoided due to high mobility states.
Innovation Solution
A mechanism where the serving macro cell sends control messages, such as Fast Moving User Indicators or Delay Waking Up Indications, to overlaying small cells to manage their power and interference modes based on the mobility state of user equipment, allowing small cells to delay waking up or mute discovery signals when fast-moving users are detected, thereby reducing unnecessary transitions and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small cells transition from sleep to active mode upon detecting user equipment, then service coverage is improved, but energy consumption increases unnecessarily for fast-moving users
Solution Approach 1:
The macro base station performs preliminary assessment of user mobility state before the small cell activates. By sending control messages indicating fast-moving user detection, the macro cell preemptively prevents unnecessary small cell activation, avoiding wasted energy consumption before it occurs.
Solution Approach 2:
The macro base station acts as an intermediary between the user equipment and small cells. It monitors user mobility and sends control messages to small cells to regulate their activation state, thereby mediating the energy consumption issue without affecting service coverage for legitimate users.
2Adaptability or versatility
If small cells activate discovery signals when user equipment is detected, then handover capability is improved, but interference increases for fast-moving users
Solution Approach 1:
The macro base station sends control messages to small cells in advance to prevent discovery signal transmission when fast-moving users are detected. This preliminary anti-action blocks the potential interference source before the user can be handed over to the small cell, eliminating harmful interference proactively.
3Use of energy by moving object
If small cells remain in sleep mode to save energy, then energy efficiency is improved, but service availability deteriorates for legitimate users
Solution Approach 1:
The small cell activation state becomes dynamic rather than static. Small cells can switch between sleep and active modes based on real-time user mobility conditions. For stationary or slow-moving users, small cells activate to provide service; for fast-moving users, they remain in sleep mode to conserve energy.
Solution Approach 2:
The system changes the operational parameters of small cells based on detected user mobility states. When fast-moving users are detected, control messages adjust the activation threshold or disable activation temporarily, changing the operational parameter from 'activate on detection' to 'remain in sleep mode'.
Data Source
AI summary
A method receiving a control message at an apparatus of a base station of a first smaller cell, said control message being provided by a control apparatus of a second larger cell, said first cell at least partially overlying said second cell, said control message being provided dependent on a speed of at least one user equipment; and causing, in response to said control message, said base station of said first cell to be in a first power and/or interference mode.