Base Station Radio Resource Allocation for IMD Mitigation
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Solution Overview
Problem
In LTE-NR dual connectivity, inter-modulation distortion (IMD) and harmonics from uplink transmissions cause intra-device interference due to the wider bandwidth of the NR system, affecting both LTE and NR component carriers, leading to adverse communication effects.
Innovation Solution
A second base station device is provided with a receiver to receive information for limiting radio resource allocation from a first base station device, a controller to allocate radio resources based on this information, and a transmitter to send this allocation information back, including details in the frequency and time domains to prevent IMD by optimizing radio resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dual connectivity between LTE and NR systems is implemented to increase data transmission capacity, then communication throughput is improved, but intra-device interference occurs due to IMD and harmonics from simultaneous uplink transmissions
Solution Approach 1:
The base station performs preliminary actions by determining resource allocation restrictions before uplink transmission occurs. The restriction information indicating forbidden resource blocks is proactively generated and transmitted to the user equipment, preventing IMD and harmonics from falling into downlink reception bands before interference can occur.
Solution Approach 2:
The base station calculates and determines resource allocation restrictions in advance based on its own resource allocation patterns. By pre-determining which resource blocks should be restricted and communicating these restrictions to the user equipment before transmission, the system prevents interference proactively rather than reactively.
2Productivity
If NR system uses wider bandwidth to improve transmission performance, then data rate is increased, but susceptibility to IMD effects is enhanced
Solution Approach 1:
Instead of uniformly restricting all frequency resources, the invention applies localized quality control by identifying and restricting only specific resource blocks where IMD and harmonics are likely to occur. The base station determines forbidden resource blocks based on its own allocation patterns, applying restrictions only where necessary rather than across the entire wide bandwidth.
Solution Approach 2:
The invention changes the parameter of resource allocation by introducing frequency-domain restrictions. The base station modifies the available resource blocks parameter by excluding specific forbidden resource blocks from allocation, thereby changing the spectral distribution of uplink transmissions to avoid IMD-prone regions.
3Productivity
If simultaneous uplink transmissions are performed in LTE and NR to improve communication efficiency, then spectral utilization is enhanced, but inter-modulation distortion occurs affecting downlink reception
Solution Approach 1:
The invention extracts and removes the harmful frequency components from the transmission spectrum by identifying forbidden resource blocks where IMD and harmonics would occur. These problematic frequency resources are taken out of the available allocation pool, preventing them from being transmitted while allowing other clean frequency resources to be utilized.
Solution Approach 2:
The invention converts the harmful effect of IMD into a beneficial constraint by using the base station's own resource allocation pattern to identify and restrict problematic frequencies. The restriction information, which limits user equipment's transmission options, actually benefits the overall system by preventing interference and ensuring clean downlink reception.
Data Source
AI summary
Disclosed is a second base station device communicating with a first base station device. The second base station device includes a receiver configured to receive, from the first base station device, information for limiting radio resource allocation; a controller configured to allocate a radio resource based on the received information for limiting radio resource allocation; and a transmitter configured to transmit information for limiting radio resource allocation to the first base station device. The information for limiting radio resource allocation includes information indicating at least one of a frequency domain and a time domain indicating a location of a radio resource.