Multiplexing Control Information Across Multiple Uplink Carriers
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Solution Overview
Problem
In wireless mobile communication systems, the simultaneous transmission of control and traffic channels is limited by power constraints and signal distortion, leading to reduced link coverage and increased transmission errors, particularly in LTE systems where DFT-S-OFDM is used, causing issues with ACK/NACK signal transmission and protocol robustness.
Innovation Solution
A method is introduced to multiplex control information across multiple uplink carriers using SC-FDMA signals, allowing for simultaneous transmission of control information on both uplink control and shared channels, with specific allocation and modulation techniques to optimize error rates and power allocation, ensuring reliable transmission of ACK/NACK, CQI, and RI signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control information is transmitted on a dedicated uplink control channel, then transmission reliability is improved, but transmission error rate increases due to power constraints and signal distortion
Solution Approach 1:
The patent combines control information with traffic channel data and transmits them together on the uplink shared channel using SC-FDMA. This merging approach allows the control information to benefit from the traffic channel's power allocation and modulation schemes, thereby reducing transmission errors while maintaining reliability through the inherent robustness of SC-FDMA signaling.
2Productivity
If control channel and traffic channel are transmitted simultaneously, then system capacity is improved, but signal distortion increases due to limited UE transmission power
Solution Approach 1:
The patent replaces traditional OFDMA-based simultaneous transmission with SC-FDMA signaling. This substitution changes the fundamental transmission mechanism to maintain single-carrier properties, which inherently reduce peak-to-average power ratio and minimize signal distortion when control and traffic channels are transmitted together, thereby enabling higher system capacity without excessive distortion.
3Loss of information
If ACK/NACK signal is mapped around uplink demodulation reference signal, then control information transmission is achieved, but available transmission power is reduced to half of maximum energy
Solution Approach 1:
The patent extracts the ACK/NACK signal from the constrained PUCCH format and transmits it embedded within the uplink shared channel alongside traffic data. This extraction from the power-limited control channel format allows the ACK/NACK signal to utilize the full power resources allocated to the uplink shared channel, thereby making available the complete maximum energy for transmission rather than being restricted to half.
4Adaptability or versatility
If multiple control channels are transmitted on different uplink carriers, then information diversity is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal SC-FDMA-based transmission framework that can carry both control information and traffic data on the uplink shared channel. This multi-functional approach allows the same transmission mechanism to handle diverse control information types (ACK/NACK, CQI, RI) across multiple carriers, thereby achieving information diversity while avoiding the complexity of separate dedicated control channel configurations.
Data Source
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AI summary
Abstract: (EN) The present invention relates to a method for transmitting control information by a terminal in a wireless mobile communication system using multiple uplink carriers. The method for transmitting control information comprises: multiplexing a first control information to be assigned to a first uplink control channel and a second control information to be assigned to a second uplink control channel; and transmitting the multiplexed first and second control information via an uplink channel that is allocated to one of the multiple uplink carriers. Here, the first uplink control channel and the second uplink control channel are respectively allocated to different uplink carriers.