Joint WLAN Power and Rate Control for LTE Interference Mitigation
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Solution Overview
Problem
Interference between Long Term Evolution (LTE) and Wireless Local Area Network (WLAN) systems causes performance degradation due to overlapping coverage areas, particularly in co-located networks where LTE transmissions can jam WLAN receivers and vice versa, leading to reduced signal quality and throughput.
Innovation Solution
Implementing joint transmission power and rate control for WLAN transmitters to minimize interference with LTE TDD systems, including reducing WLAN transmission power to avoid de-sensing LTE receivers and selecting lower data rates to maintain signal quality, while allowing concurrent operations of LTE and WLAN transceivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If WLAN transmission power is increased to improve WLAN throughput, then WLAN data rate is improved, but interference to LTE receiver increases causing performance degradation
Solution Approach 1:
The WLAN transmitter dynamically adjusts its transmission power and data rate based on real-time detection of LTE receiver activity. When LTE receiver activity is detected, the WLAN transmitter reduces power or suspends transmission to minimize interference. This dynamic adaptation allows the system to optimize WLAN throughput when LTE is not active while protecting LTE reception when it is active, resolving the contradiction between WLAN performance and LTE interference.
Solution Approach 2:
The system implements a feedback mechanism where the WLAN transmitter monitors LTE receiver activity and adjusts its transmission parameters accordingly. The feedback loop detects when the LTE receiver is active and triggers power reduction or transmission suspension in the WLAN system. This closed-loop control enables the WLAN system to automatically adapt its behavior to prevent harmful interference while maintaining optimal throughput when conditions permit.
2Productivity
If WLAN and LTE transceivers operate concurrently to improve system utilization, then overall network efficiency is improved, but mutual interference increases causing performance degradation
Solution Approach 1:
The system employs periodic action by suspending WLAN transmission during LTE receiver time slots and allowing WLAN transmission during LTE transmitter time slots. This time-division approach enables both systems to operate concurrently without continuous mutual interference. The periodic suspension and resumption of WLAN transmission based on LTE frame structure allows both networks to achieve reasonable utilization while minimizing harmful interference effects.
Solution Approach 2:
The WLAN transmitter dynamically switches between active and suspended states based on the detected LTE transmission pattern. When LTE transmitter activity is detected, WLAN operates normally; when LTE receiver activity is detected, WLAN suspends or reduces transmission. This dynamic state transition enables concurrent operation of both systems while automatically avoiding the harmful interference that would occur with continuous simultaneous operation.
3Object-affected harmful factors
If WLAN transmission power is reduced to minimize LTE interference, then interference to LTE receiver is reduced, but WLAN signal quality deteriorates
Solution Approach 1:
The WLAN transmitter dynamically adjusts power levels based on the operational state of the LTE receiver. When LTE receiver activity is detected, power is reduced to minimize interference. When LTE receiver activity is not detected, power is increased to maintain high WLAN signal quality and throughput. This dynamic power adjustment ensures that WLAN signal quality is compromised only temporarily during LTE reception periods, while maintaining high quality during LTE transmission periods.
Solution Approach 2:
The system performs preliminary detection of LTE receiver activity before initiating WLAN transmission. By detecting the LTE frame structure and receiver time slots in advance, the WLAN transmitter can proactively adjust its power or suspend transmission before interference occurs. This preliminary action prevents the need for aggressive continuous power reduction, allowing the system to maintain high WLAN signal quality during periods when interference is not an issue.
Data Source
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AI summary
A method performed at a wireless local area network (WLAN) transmitter of a communication system in response to interference with a long term evolution (LTE) receiver, the method comprising: determining a WLAN frame aggregation size based on a transmission rate for the WLAN transmitter and an LTE frame configuration for the LTE receiver; determining a throughput based on the transmission rate and the WLAN frame aggregation size; determining the throughput is greater than a throughput for a current transmission rate and a current frame size; and in response to determining the throughput is greater, transmitting data during a downlink receiving period of the LTE receiver using the transmission rate and the WLAN frame aggregation size.