Uplink Signal Mapping Control for CP-OFDM and Frequency Hopping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Future radio communication systems face challenges in properly transmitting uplink signals when supporting both DFT-spread OFDM and CP-OFDM waveforms, and in achieving frequency diversity when applying frequency hopping to uplink data channels, leading to potential declines in communication quality.
Innovation Solution
A user terminal is designed to control the mapping direction of uplink signals between time and frequency directions based on the waveform used and whether frequency hopping is applied, allowing for proper transmission and frequency diversity gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same mapping method as existing LTE systems is used for future radio communication systems supporting both DFT-spread OFDM and CP-OFDM waveforms, then device complexity is reduced, but proper transmission of uplink signals cannot be achieved
Solution Approach 1:
The mapping method is made dynamic by selecting between time-direction mapping and frequency-direction mapping based on the waveform type (DFT-spread OFDM or CP-OFDM) and frequency hopping configuration. This allows the system to adapt the mapping approach to match the specific transmission requirements of different waveform modes, ensuring proper signal transmission while managing complexity through conditional logic rather than fixed rigid rules.
Solution Approach 2:
The patent changes the mapping direction parameter based on transmission conditions. When CP-OFDM waveform is used or frequency hopping is applied, the mapping direction is changed from the conventional frequency-direction first approach to time-direction first approach. This parameter change enables proper resource element mapping for the specific waveform type and frequency hopping scenario.
2Ease of operation
If conventional mapping method is used without modification, then ease of operation is maintained, but frequency diversity cannot be achieved at satisfactory level
Solution Approach 1:
The mapping operation is enhanced dynamically by adjusting the mapping direction based on whether frequency hopping is configured. When frequency hopping is enabled, the system switches to time-direction first mapping, which properly distributes resources across frequency hops and achieves frequency diversity. This dynamic adjustment maintains operational simplicity through automated condition-based selection rather than manual configuration.
Solution Approach 2:
The mapping method incorporates feedback from the frequency hopping configuration status. The control section receives information about whether frequency hopping is configured and uses this feedback to determine the appropriate mapping direction. This feedback mechanism ensures that the mapping operation adapts to the actual transmission mode, achieving frequency diversity when needed while maintaining simplicity through automated decision-making.
3Reliability
If frequency hopping is applied to uplink shared channel, then communication coverage is improved, but mapping control complexity increases
Solution Approach 1:
The mapping control handles frequency hopping complexity dynamically by using conditional logic that activates only when frequency hopping is configured. The system maintains simple conventional mapping when frequency hopping is not used, and automatically switches to time-direction first mapping when frequency hopping is enabled. This dynamic approach manages the increased complexity through context-aware adaptation rather than requiring complex handling in all cases.
Solution Approach 2:
The patent applies different mapping qualities locally based on transmission conditions. Instead of using a single complex mapping method universally, the system applies simple frequency-direction mapping when frequency hopping is not configured, and time-direction mapping only when frequency hopping is enabled. This local quality approach optimizes mapping control for each specific scenario, reducing overall complexity while maintaining communication coverage benefits.
Data Source
AI summary
To control transmission of UL signals properly even when a CP-OFDM waveform is supported in the UL, in addition to a DFT-spread OFDM waveform, and/or support is provided for applying frequency hopping to a UL shared channel, one aspect of the present invention provides a user terminal, which has a transmission section that transmits a UL signal by using a UL shared channel, and a control section that controls a direction in which the UL signal is first mapped, between a time direction and a frequency direction, based on a waveform of the UL shared channel and/or whether or not frequency hopping is applied to the UL shared channel.