SC-FDMA Uplink Control Signal Transmission
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Solution Overview
Problem
There is a need for a method to transmit control signals from user equipment to a base station with high reliability in wireless communication systems, particularly in the uplink direction, while minimizing radio resources and reducing Peak-to-Average Power Ratio (PAPR) to conserve battery power and improve coverage.
Innovation Solution
The method employs a transmitter that uses SC-FDMA modulation, combining Discrete Fourier Transform (DFT) and Inverse Fast Fourier Transform (IFFT) to modulate control signals and user data, allowing for efficient multiplexing and allocation of radio resources, including frequency division multiplexing and code division multiplexing techniques to ensure reliable transmission under varying channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM/OFDMA system is used to provide high data rate, then communication capacity is improved, but Peak-to-Average Power Ratio (PAPR) becomes very high causing power consumption problems
Solution Approach 1:
The patent changes the fundamental transmission parameter from multi-carrier OFDM to single-carrier SC-FDMA, transforming the signal structure to inherently lower PAPR while maintaining frequency division multiplexing capabilities. This parameter change resolves the contradiction by achieving both high communication capacity through resource block allocation and low power consumption through reduced peak amplitudes.
2Reliability
If control signal transmission reliability is improved through dedicated resources, then transmission reliability is improved, but radio resources available for user data decrease
Solution Approach 1:
The patent merges control signal transmission with user data transmission by multiplexing control signals onto the same physical uplink shared channel (PUSCH) resources used for user data. This combining approach achieves both high control signal reliability through proper coding and modulation, and maintains high user data rates by utilizing the same radio resources efficiently without dedicated separate resources.
3Use of energy by moving object
If SC-FDMA is used to reduce PAPR and improve power efficiency, then power consumption is reduced, but system complexity increases due to DFT and IFFT operations
Solution Approach 1:
The patent implements dynamic resource block allocation and adaptive modulation schemes within the SC-FDMA framework, allowing the system to optimize the balance between power efficiency and processing complexity based on channel conditions and traffic requirements. This dynamic approach manages the inherent DFT/IFFT complexity by adapting resource usage patterns rather than reducing the fundamental SC-FDMA operations.
Data Source
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AI summary
There is provided a method of enabling a user equipment to transmit a control signal to a base station. The method includes allocating a control signal to a control region on a subframe, the subframe comprising the control region for the control signal and a data region for user data, wherein different frequency bands within the control region are allocated to different user equipments, and transmitting the subframe in uplink direction. A control signal can be robustly transmitted under variance of channel condition.