PSNB Base Station Coordination for LTE Interference Mitigation
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Solution Overview
Problem
Broadband radio transmitters, such as 700 MHz LTE transmitters, cause out-of-band emissions that interfere with nearby narrowband receivers like Public Safety receivers, leading to desensitization due to reduced Signal-to-Noise Ratio, despite the use of guard bands and RF filters, which are insufficient in protecting mission-critical narrowband transmissions.
Innovation Solution
A method and apparatus for managing resources in a multi-technology wireless communication system that involves a broadband data network and a Public Safety Narrowband network, where a base station in the PSNB network informs the eNodeB of a voice session initiation and allocated resources, causing the eNodeB to avoid allocating spectrally proximate resources to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a broadband transmitter operates in close proximity to a narrowband receiver, then broadband data transmission capacity is improved, but out-of-band emissions cause interference to the narrowband receiver resulting in receiver desensitization
Solution Approach 1:
The system applies preliminary anti-action by having the broadband base station proactively identify when a narrowband receiver is present in its coverage area and preemptively adjust its transmission parameters (power, frequency allocation) before interference occurs, rather than reacting after the narrowband receiver is desensitized
Solution Approach 2:
The system implements dynamics by making the broadband transmission parameters adjustable and adaptive based on the presence and state of narrowband receivers. The broadband base station dynamically modifies its operation in response to real-time conditions, switching between different transmission modes to balance broadband capacity with narrowband protection
2Manufacturing precision
If a guard band is inserted between broadband and narrowband frequency bands, then spectral separation is improved, but out-of-band emissions still spill into the narrowband bandwidth causing receiver desensitization
Solution Approach 1:
The system applies parameter changes by adjusting broadband transmission parameters such as power spectral density, modulation scheme, and frequency allocation based on the presence of narrowband receivers. This dynamic parameter adjustment reduces out-of-band emissions more effectively than static guard bands alone
3Object-affected harmful factors
If RF filters are used to protect narrowband receivers, then some interference protection is achieved, but filters cannot eliminate interference entirely and mission-critical narrowband transmissions remain vulnerable
Solution Approach 1:
The system introduces an intermediary mechanism where the broadband base station acts as a cooperative entity that receives information about narrowband receiver presence and actively adjusts its transmissions to protect them. This intermediary coordination between systems provides more reliable protection than passive filtering alone
Data Source
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AI summary
A wireless communication system is provided that comprises a base station (BS) serving a subscriber unit (SU) in a Public Safety Narrowband (PSNB) network, an eNodeB serving the SU in a broadband data network, and a network element of the PSNB network that is in communication with the BS and that identifies the eNodeB to the BS. In response to the identification of the eNodeB, the BS informs the eNodeB, via an interface between a radio access network (RAN) of the PSNB network and a RAN of the broadband data network, of an initiation of a voice session in the PSNB network involving the SU and of PSNB network resources allocated to the session. In response to being informed of the initiation of the session and the allocated PSNB network resources, the eNodeB avoids allocation of resources to the SU that are spectrally proximate to the allocated PSNB network resources.