Co-located Radio Interference Mitigation via Dynamic Scheduling
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Solution Overview
Problem
Out of band emissions (OOBE) from LTE networks interfere with legacy LMR communications in public safety networks, causing undesirable radio interference in co-located devices, which existing solutions like band pass filters cannot fully eliminate.
Innovation Solution
Establishing a data link between co-located LMR and LTE mobile devices to adjust operational parameters such as power level, transmission frequency, and resource block allocation to mitigate interference, including pausing or rescheduling LTE transmissions based on prioritization hierarchies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If band pass filters are used to reduce out of band emissions, then some interference mitigation is achieved, but existing solutions cannot fully eliminate the interference
Solution Approach 1:
The patent introduces a data link as an intermediary communication channel between the LTE mobile device and LMR base station. This data link enables coordination and control signaling that allows the LTE device to adjust its transmissions based on real-time LMR traffic conditions, providing a more effective solution than passive filtering alone
Solution Approach 2:
The system implements feedback mechanisms where the LMR base station sends indication signals to the LTE mobile device about LMR traffic conditions and interference levels. The LTE device uses this feedback to dynamically adjust transmission parameters such as power level, timing, and resource block allocation, creating a closed-loop control system that actively mitigates interference
2Object-affected harmful factors
If LTE transmissions are paused or rescheduled to reduce interference, then OOBE is reduced, but transmission efficiency may be impacted
Solution Approach 1:
The patent implements dynamic adjustment of LTE transmission parameters based on real-time conditions. The system can pause or reschedule transmissions when interference is detected, but also quickly resumes normal operation when conditions improve. This dynamic responsiveness allows the system to minimize interference while maintaining overall transmission efficiency through adaptive rather than static control
Solution Approach 2:
The system performs preliminary actions by establishing the data link and receiving interference indication signals before actual interference problems occur. The LTE device can proactively adjust transmission parameters in anticipation of interference issues, rather than reacting after interference has already impacted communications, thereby maintaining higher efficiency
3Reliability
If operational parameters are adjusted to mitigate interference, then communication quality is maintained, but device complexity increases
Solution Approach 1:
The data link serves multiple functions: it carries user data, enables coordination control signaling, and facilitates interference mitigation. By consolidating these functions into a single communication channel between the LTE device and LMR base station, the system avoids the need for separate complex control systems and reduces overall device complexity
Data Source
AI summary
Methods and apparatus are provided for mitigating interference between spectrally distinct wireless communication networks employing co-located, collaborating radios. A first base station is in a first network and communicates with a first radio within a first frequency range, and a second base station is in a second network and communicates with a second radio in a second frequency range. The first and second radios are geographically co-located, for example, within a public safety vehicle. The first radio determines a maximum level of interference it will accept based on current operational parameters, and communicates a corresponding threshold value to the second radio through a data link. The second radio sends a request to its base station to employ interim scheduling constraints governing uplink transmissions from the second radio, to thereby limit out of band emissions received by the first radio to a range that is less than the threshold interference level.