Efficient Bandwidth Downscaling for LTE Systems
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Summary
Problems
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 solutions
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.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If standard LTE Release 8 bandwidth configurations are used, then device compatibility is maintained, but spectral efficiency is reduced when arbitrary bandwidths are needed
Why choose this principle:
The patent changes the bandwidth parameter from fixed standard values to arbitrary values by allowing the system to operate with any bandwidth configuration. This is achieved through IFFT-based signal transformation that adapts to the desired bandwidth while maintaining LTE compatibility, thus resolving the contradiction between bandwidth flexibility and spectral efficiency.
Principle concept:
If larger bandwidth is allocated to exceed transmission bandwidth, then more spectrum is utilized, but emission limits are violated
Why choose this principle:
The patent segments the frequency domain representation by applying zeros to specific subcarriers that would exceed the transmission bandwidth. This segmentation allows the system to utilize more spectrum resources in the IFFT domain while ensuring that the actual transmitted signal remains within the licensed bandwidth limits, thus resolving the contradiction between spectrum utilization and emission compliance.
Application Domain
Data Source
AI summary:
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.
Abstract
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.