Flexible TDD Interference Coordination in Heterogeneous Networks
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Solution Overview
Problem
In heterogeneous wireless communication networks, particularly in HetNet scenarios, there is a challenge in managing interference between macro and femto base stations, especially when femto BSs operate in downlink mode and macro BSs in uplink mode, leading to significant interference that existing interference cancellation methods fail to address effectively.
Innovation Solution
A method where a macro base station assesses and coordinates the measurement of interference caused by femto base stations operating in flexible time division duplex mode, determining necessary downlink power control parameters to adjust femto BS transmission power, ensuring minimal disturbance to macro uplink operations, by using reference signals and channel condition measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If femto base stations operate in downlink mode with high transmission power, then femto BS coverage and data rates are improved, but interference to macro uplink operations increases significantly
Solution Approach 1:
The patent implements dynamic transmission power adjustment for femto base stations based on real-time channel conditions and interference levels. The macro BS coordinates with femto BSs to continuously monitor channel quality and adjust downlink power control parameters dynamically, allowing the system to adapt power levels according to varying network conditions rather than using fixed power settings.
Solution Approach 2:
The patent changes the transmission power parameter of femto base stations based on assessed interference levels. The macro BS evaluates the amount of interference caused by femto BSs and sends coordination messages to adjust downlink power control parameters, thereby changing the power parameter to maintain acceptable interference levels while preserving coverage.
2Productivity
If flexible time division duplex mode is implemented to adapt to varying traffic conditions, then spectrum efficiency is improved, but interference management complexity increases
Solution Approach 1:
The patent creates a universal coordination framework where the macro base station performs multiple functions: assessing interference levels, coordinating measurements, deciding power adjustments, and sending control messages. This centralized multi-functional approach at the macro BS level simplifies the overall system by consolidating interference management tasks rather than requiring complex distributed coordination between multiple femto BSs.
Solution Approach 2:
The patent implements a feedback mechanism where the macro BS assesses interference caused by femto BSs and sends coordination messages back to adjust their transmission parameters. This closed-loop feedback system allows the network to automatically adapt to changing conditions and maintain optimal performance without manual intervention, managing complexity through automated responsive control.
3Reliability
If interference cancellation methods are used to mitigate cross-direction interference, then macro uplink performance is improved, but system complexity and backhaul requirements increase
Solution Approach 1:
Instead of attempting to cancel interference through complex signal processing, the patent converts the harmful interference problem into a manageable power control issue. By proactively adjusting femto BS downlink power levels to prevent excessive interference, the system transforms a potential harm (interference) into a controlled parameter, eliminating the need for complex interference cancellation algorithms while maintaining macro uplink performance.
Data Source
AI summary
One embodiment is directed to a method for operating base stations in a heterogeneous network. The method may include receiving, by a first base station, an indication for a second base station to use flexible time division duplex mode (502), assessing an amount of interference that will be caused by the second base station (504)-(508), deciding how to adjust a transmission power of the second base station (509), and sending the second base station a request to adjust the transmission power (510).