MTC Terminal Frequency Hopping via SC-FDMA Symbol Puncturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In MTC communication systems, particularly in LTE-Advanced Rel-13 terminals, there is a need to secure retuning time for frequency hopping while minimizing the deterioration of uplink transmission characteristics, as these terminals operate with a limited 1.4-MHz frequency band and do not receive existing LTE downlink control channels, requiring innovative methods to manage retuning without degrading signal quality.
Innovation Solution
A terminal configuration that punctures specific SC-FDMA symbols in one subframe and uses them as retuning time for frequency hopping, allowing seamless switching between narrowbands, thereby securing retuning time without compromising transmission characteristics by using Methods 1 to 3, which involve discarding last or first symbols of subframes for retuning, ensuring efficient resource use and maintaining orthogonality between orthogonal cover code sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If retuning time is secured by puncturing SC-FDMA symbols for frequency hopping, then retuning capability is improved, but transmission characteristics deteriorate
Solution Approach 1:
The patent applies preliminary action by puncturing specific SC-FDMA symbols in advance before frequency hopping occurs. By removing these symbols beforehand, the terminal creates dedicated retuning time slots that ensure smooth frequency transitions without disrupting the overall transmission structure, thus improving adaptability while maintaining reliability.
Solution Approach 2:
The patent segments the SC-FDMA symbol structure by identifying and puncturing specific symbols (first symbol in second subframe, last symbol in first subframe) to create dedicated retuning intervals. This segmentation allows frequency hopping to occur at controlled points without affecting the integrity of the remaining transmission symbols, resolving the contradiction between hopping capability and transmission quality.
2Productivity
If frequency hopping is implemented in MTC terminals, then spectral efficiency is improved, but resource use efficiency deteriorates due to retuning time requirements
Solution Approach 1:
The patent applies partial action by puncturing only the minimum necessary symbols (one symbol from each of two consecutive subframes) to provide retuning time. This partial puncturing approach ensures that frequency hopping can be implemented to improve spectral efficiency, while the retuning time loss is minimized to only what is absolutely necessary for the frequency transition.
3Productivity
If puncturing of SC-FDMA symbols is performed to secure retuning time, then resource use efficiency is improved, but orthogonality between orthogonal cover code sequences may collapse
Solution Approach 1:
The patent applies local quality by selectively puncturing only specific SC-FDMA symbols (first symbol of second subframe, last symbol of first subframe) rather than uniformly puncturing all symbols. This localized puncturing approach creates retuning opportunities without disrupting the orthogonality of orthogonal cover code sequences across the majority of transmission symbols, thus improving resource efficiency while maintaining sequence orthogonality.
Data Source
AI summary
In the present invention, regarding a narrowband used in a subframe for transmitting uplink data, if a switch is made from a first narrowband used in a first subframe to a second narrowband that is different from the first narrowband, with respect to a second subframe continuing to the first subframe, a final one symbol of the first subframe and an initial one symbol of the second subframe are punctured and set as a retuning time to transmit the uplink data in the first narrowband and the second narrowband.