Power Headroom Scheduling for LTE Self-Interference
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Solution Overview
Problem
In LTE wireless communication networks, inadequate attenuation between uplink and downlink channels leads to interference and inefficiencies, particularly when frequency bands are close, causing self-interference and failing to meet coexistence requirements, which existing methods attempt to address by limiting bandwidth but introduce inefficiencies.
Innovation Solution
A method employing a processor to schedule transmissions on user equipment, determining inadequate attenuation through feedback reports, and adjusting scheduling to provide adequate attenuation by changing frequency bands or power levels on either uplink or downlink channels to mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If system bandwidth is limited to provide co-existence and avoid self-desensitization, then interference between channels is reduced, but scheduling gains are reduced and overhead increases
Solution Approach 1:
The patent implements dynamic scheduling that adjusts resource allocation based on real-time power headroom reports from user equipment. The eNodeB modifies uplink resource grants dynamically to ensure adequate attenuation between uplink and downlink channels while preserving scheduling flexibility and gains, rather than imposing static bandwidth limits.
Solution Approach 2:
The system changes scheduling parameters (resource block allocation, power levels) based on power headroom information to achieve adequate channel attenuation. By adjusting these parameters dynamically, the system maintains co-existence requirements without reducing overall system bandwidth or sacrificing scheduling efficiency.
2Reliability
If independent carriers are used instead of wider band allocation, then co-existence is improved, but overhead increases and efficiency decreases
Solution Approach 1:
The patent enables a single carrier to perform multiple functions by dynamically allocating resources within a wide bandwidth. The scheduling mechanism allows the same carrier to serve multiple users with different power headroom conditions while maintaining adequate attenuation, eliminating the need for separate independent carriers and their associated overhead.
3Reliability
If uplink transmit power is increased, then uplink signal quality is improved, but attenuation to downlink frequency band becomes inadequate causing interference
Solution Approach 1:
The system uses power headroom reports as feedback from user equipment to the eNodeB. Based on this feedback, the eNodeB adjusts uplink resource allocations to achieve the necessary attenuation to downlink frequencies while maintaining adequate uplink signal quality. This closed-loop control prevents both over-powering (causing interference) and under-powering (reducing quality).
Data Source
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AI summary
User equipment reports periodically or aperiodically serving cell reference signal received power and quality as well as uplink power headroom information to the serving evolved NodeB (eNB). eNB calculates a current interference level experienced by the UE from the feedback report and its own loading. Since the self-interference is not flat across frequencies, the tolerable self-interference level depends on downlink scheduling. From the calculated interference, eNB can calculate uplink allocation parameters. Sequence of scheduling decisions can be downlink allocation, determining tolerable self-interference, and uplink allocation, or in the opposite order, or the downlink and uplink allocation can be jointly determined using the available. An additional scheduling constraint can be derived for meeting the co-existence requirements, which can be determined from the power headroom report alone. Thereby interference to other user equipment or self-interference (self-desensitization) is addressed when inadequate attenuation exists while also allowing deploying full system bandwidth.