Adaptive Power Reduction for LTE Adjacent Channel Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication networks face interference issues due to adjacent channel transmissions, particularly in scenarios where LTE transmissions near public safety bands, leading to potential interference with narrow band systems like the public safety band between 851-859 MHz, necessitating effective power reduction methods to maintain network coverage and protect adjacent bands.
Innovation Solution
The implementation of Adaptive Maximum Power Reduction (A-MPR) tables that utilize the ending resource block (RB) index and contiguous RB allocation length to determine optimal power relaxation allowances, adjusting transmission power to minimize interference while ensuring data coverage, particularly by defining A-MPR values for specific channel bandwidths and offsets to protect adjacent bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If maximum power reduction is applied to protect adjacent bands, then interference to public safety communications is reduced, but network coverage and uplink performance deteriorate
Solution Approach 1:
The patent applies different power reduction strategies to different resource block regions. Region 1 (first N RBs from start) and Region 3 (last N RBs from end) apply higher power reduction to protect adjacent bands, while Region 2 (middle RBs) maintains higher power for reliable communication. This local differentiation resolves the contradiction by protecting adjacent bands where needed while preserving network coverage in critical regions.
Solution Approach 2:
The patent segments the uplink bandwidth into three distinct regions based on resource block allocation. By dividing the frequency spectrum into protected regions (near band edges) and non-protected regions (center band), the system can apply targeted power control policies to each segment, reducing interference to public safety bands while maintaining overall network coverage.
2Object-affected harmful factors
If transmission power is reduced near public safety bands, then interference to narrow band systems is minimized, but uplink data rate and communication quality deteriorate
Solution Approach 1:
The patent implements location-dependent power control where the power reduction amount varies based on the resource block's position in the frequency spectrum. RBs in Region 1 and Region 3 (close to band edges) experience higher power reduction to protect public safety bands, while RBs in Region 2 (center band) maintain higher power levels to preserve uplink data rate and communication quality.
Solution Approach 2:
The patent dynamically changes the transmission power parameter based on the resource block allocation pattern and position. By adjusting the power spectral density differently across various RB regions and modifying the maximum power reduction values based on uplink grant size and RB index, the system optimizes the trade-off between interference protection and data rate maintenance.
3Measurement precision
If adaptive power relaxation allowance is implemented based on RB allocation, then interference control precision is improved, but device complexity and computational overhead increase
Solution Approach 1:
The patent introduces dynamic parameters including uplink grant size, resource block index, and power spectral density as variables in the power relaxation allowance calculation. These parameters are adjusted based on the specific RB allocation pattern and transmission conditions, enabling precise interference control that adapts to different channel and traffic scenarios without requiring complex algorithms.
Solution Approach 2:
The patent implements dynamic power control where the power relaxation allowance changes based on real-time conditions such as RB allocation length, starting and ending RB indices, and uplink grant size. This dynamic adjustment mechanism provides precise interference control adapted to varying transmission scenarios while maintaining manageable device complexity through standardized calculation procedures.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Techniques for determining power relaxation values are disclosed. The power relaxation values may be determined according to an ending; resource block (RB) and a number of RBs in a contiguous allocation. In one aspect, the power relaxation values are arranged into regions based, at least in part, on transmission channel bandwidths and the distance from a protected adjacent channel. A user equipment (UE) can determine a power relaxation value for its current allocation using the ending RB index and contiguous RB length and can adjust its transmission power accordingly. Evolved NodeBs may estimate the power relaxation that a particular UE has selected in order to more accurately determine the transmit power available to the UE. Using the more accurate estimate of transmit power, the eNB may schedule the UE for uplink transmissions accordingly.