LTE Bandwidth Downscaling Using PRB Blanking and Control Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The standard LTE Release 8 wireless communication systems are limited to specific downlink system bandwidths, which can lead to reduced spectral efficiency or violations of emission limits, as they do not support arbitrary bandwidths, resulting in inefficient spectrum use and compliance issues.
Innovation Solution
The method involves determining a larger bandwidth and fitting it into a smaller transmission bandwidth by blanking physical resource blocks at the edges, transforming the signal using an inverse Fourier transform with applied zeros at the blanked blocks, and filtering the signal to ensure transmission within the original bandwidth limits, allowing for more flexible and efficient spectrum use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standardized LTE Release 8 bandwidths are used, then system compatibility is maintained, but spectral efficiency is reduced when operator-selected bandwidths do not match standardized options
Solution Approach 1:
The patent changes the bandwidth parameter from fixed standardized values to arbitrary operator-selected values by introducing a bandwidth scaling factor that maps standardized resource block allocations to the actual available bandwidth, enabling continuous bandwidth adaptation rather than discrete standardized steps
Solution Approach 2:
The system dynamically adjusts resource block allocations and control channel configurations based on the operator-selected bandwidth, allowing the network to adapt its parameters in real-time to match the actual spectral availability rather than being constrained by static standardized bandwidth options
2Adaptability or versatility
If larger standardized bandwidth is used to match operator selection, then bandwidth flexibility improves, but emission limits are violated
Solution Approach 1:
The patent introduces a bandwidth scaling mechanism that adjusts the effective transmission bandwidth parameter to match the operator-selected bandwidth while maintaining proper power spectral density distribution, ensuring emission limits are met regardless of the selected bandwidth size
Solution Approach 2:
The system applies partial resource block allocations and scales control channel transmissions to match the actual available bandwidth, avoiding excessive transmission power in any single frequency region while still utilizing the full operator-selected bandwidth efficiently
3Object-affected harmful factors
If smaller standardized bandwidth is used to comply with emission limits, then emission compliance is achieved, but spectral efficiency is reduced
Solution Approach 1:
The patent changes the resource allocation parameters to scale efficiently within the available bandwidth by adjusting the number of resource blocks and their distribution, maximizing spectral efficiency within the constraints of the operator-selected bandwidth while maintaining emission compliance
Solution Approach 2:
The system dynamically optimizes resource block assignments and control channel configurations based on the actual available bandwidth, ensuring that each Hz of spectrum is utilized as efficiently as possible while maintaining proper power spectral density to comply with emission limits
4Adaptability or versatility
If arbitrary bandwidths are supported, then bandwidth flexibility improves, but system complexity increases due to non-standardized configurations
Solution Approach 1:
The patent creates a universal bandwidth scaling mechanism that works across all LTE Release 8 configurations by introducing a scaling factor that adapts standardized resource block allocations to any arbitrary bandwidth, maintaining compatibility with existing standardized equipment while enabling non-standardized bandwidth options
Solution Approach 2:
The system introduces a bandwidth scaling factor as an intermediary parameter that translates between standardized resource block definitions and arbitrary bandwidth selections, allowing the network to support flexible bandwidth configurations without requiring separate configuration schemes for each bandwidth size
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables more efficient use of available spectrum while remaining within regulatory emission limits, improving spectral efficiency and supporting arbitrary bandwidths without requiring changes to standard LTE base stations or handsets.
Implementation Method 1
transforming a signal to be transmitted using an inverse Fourier transform for the larger second bandwidth for which zeros are applied at the blanked physical resource blocks
Implementation Method 2
filtering the transformed signal to the first transmission bandwidth
Data Source
AI summary
A larger second bandwidth is fitted to a first transmission bandwidth by blanking PRBs at one or both edges of the larger second bandwidth. A first set of control channels is mapped to unblanked PRBs of the second bandwidth using a restricted set of physical cell identities that map only to the unblanked PRBs. A second control channel is punctured so that after it is interleaved and cyclically shifted the punctured CCEs fall on the blanked PRBs, and this second control channel is power compensated for the punctured CCEs. The first set and the second control channels are assigned in view of the puncturing and blanked PRBs, an IFFT for the larger second bandwidth is performed on a signal using zeros at the blanked PRBs, the signal is filtered to the first bandwidth and transmitted over a bandwidth not to exceed the first bandwidth.