Uplink Control Channel Frequency Offset for Interference Reduction
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Solution Overview
Problem
In wireless communication systems, neighboring operating bands often experience signal interference due to limited guard bands and spurious emissions from radio frequency impairments, leading to significant interference with public safety and other equipment.
Innovation Solution
The uplink control channel is relocated away from the edge of the wideband frequency resource towards a medial portion, and/or a power limitation is imposed on user equipment transmitting on this channel to reduce out-of-band interference, using techniques such as dynamic offsetting and power reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the uplink control channel is located at the edge of the wideband frequency resource to provide diversity and avoid fragmentation, then resource allocation efficiency is improved, but interference with neighboring bands increases
Solution Approach 1:
The patent applies dynamic offsetting where the control channel location is adjusted based on interference conditions. The control channel can be dynamically relocated from the edge position (which causes interference) to an offset position (which reduces interference), allowing the system to adapt between resource allocation efficiency and interference reduction based on current operating conditions
Solution Approach 2:
The patent changes the frequency domain parameter of the control channel location. By modifying the control channel's frequency offset parameter, the system can move the control channel away from band edges when interference is detected, thereby reducing spurious emissions to neighboring bands while maintaining adequate resource allocation
2Reliability
If transmit power is increased to improve communication reliability, then signal quality is improved, but spurious emissions and interference increase
Solution Approach 1:
The patent applies power reduction as a parameter change strategy. By reducing the transmit power parameter for control channel transmissions, the system lowers spurious emissions and interference to neighboring bands while maintaining adequate communication reliability through the use of offset positioning and adaptive power control
Solution Approach 2:
The patent applies preliminary anti-action by proactively reducing transmit power and offsetting control channel positions before interference problems occur. This preventive approach addresses spurious emissions at their source by controlling transmit parameters in advance, rather than attempting to mitigate interference after it occurs
Data Source
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AI summary
A wireless communication infrastructure entity in a wireless communication system implementing an uplink control channel using a narrowband frequency resource within a wideband frequency resource. The entity includes a controller communicably coupled to a transceiver wherein the controller is configured to cause the transceiver to signal a change of location for an uplink control channel within the wideband frequency resource. The uplink control channel includes at least a pair of uplink control channels separated within the wideband frequency resource and accommodates simultaneous uplink transmissions by multiple user equipments communicating in the wireless communication system.