Mitigating Self-Interference in LTE Carrier Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE cellular communications networks, carrier aggregation poses a significant design challenge due to self-interference issues, where uplink transmissions by User Equipment (UE) result in intermodulation products that fall within downlink component carriers, impairing receiver performance and requiring effective mitigation methods.
Innovation Solution
A network node obtains self-interference parameters, including frequency location and strength, to control uplink and downlink transmissions and receptions, such as PUCCH, PUSCH, PDSCH, and PDCCH resource allocations, to mitigate self-interference by adjusting transmission and reception strategies, such as avoiding interference-prone subframes or using inner resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carrier aggregation is utilized to support bandwidths larger than 20 MHz, then the bandwidth capacity is improved, but self-interference occurs wherein uplink transmissions create intermodulation products that fall within downlink component carriers
Solution Approach 1:
The network node determines self-interference parameters (frequency location, strength) before allocating uplink and downlink resources. This preliminary assessment allows the system to identify potential intermodulation products and configure resource allocations that avoid these harmful frequencies, preventing self-interference before it occurs
Solution Approach 2:
The system dynamically adjusts resource allocation parameters (frequency assignments, time scheduling) based on determined self-interference characteristics. By changing these parameters according to the measured interference profile, the system can allocate resources in frequency-time domains that avoid overlapping with intermodulation products while maintaining aggregate bandwidth capacity
2Reliability
If uplink and downlink frequency bands are paired with sufficient separation, then receiver performance is improved, but the frequency resources available for carrier aggregation are reduced
Solution Approach 1:
The wireless device performs self-interference measurement by transmitting test signals and measuring the resulting intermodulation products in its own receiver. This self-service approach allows the device to characterize its own interference profile without requiring external measurement infrastructure, enabling the network to allocate resources that account for device-specific interference characteristics
Data Source
AI summary
Systems and methods for mitigating self-interference at a wireless device in a cellular communications network are disclosed. In one embodiment, a network node obtains one or more self-interference parameters for self-interference at the wireless device within a downlink frequency band utilized by the wireless device. In one embodiment, the one or more self-interference parameters include a frequency location of the self-interference, a strength of the self-interference, or both the frequency location and the strength of the self-interference. The network node then controls uplink transmission by the wireless device, downlink reception by the wireless device, and/or downlink transmission to the wireless device in such a manner that the self-interference at the wireless device is mitigated.