PUCCH ACK/NACK Phase Shift Diversity
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Solution Overview
Problem
Current PUCCH formats in wireless communication systems do not adequately differentiate the performance of ACK/NACK bits from other control bits like CQI and PMI, leading to insufficient protection and error rates, especially with the introduction of carrier aggregation in LTE-A, which requires improved ACK/NACK reliability.
Innovation Solution
A transmission diversity scheme using phase shift patterns on the physical uplink control channel (PUCCH) with ACK/NACK differentiation, where coded UCI is mapped to QPSK symbols and phase shifted based on ACK/NACK, and transmitted using multiple antennas to enhance reliability and error protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current PUCCH formats are used without ACK/NACK differentiation, then device complexity remains low and compatibility is maintained, but ACK/NACK reliability and error protection are insufficient
Solution Approach 1:
The patent applies local quality by differentiating the treatment of ACK/NACK bits from other control bits (CQI, PMI). Specifically, ACK/NACK bits are mapped to QPSK symbols while other bits are mapped differently, and phase shift patterns are applied selectively based on ACK/NACK status. This localized differentiation provides enhanced error protection for ACK/NACK without requiring complete redesign of the entire PUCCH format.
Solution Approach 2:
The patent segments the control information into different components (ACK/NACK bits, CQI, PMI) and applies different mapping and modulation techniques to each segment. The ACK/NACK bits are separated and given special treatment with phase shift patterns, while other control bits follow conventional mapping. This segmentation allows targeted improvement of ACK/NACK reliability without affecting overall system complexity excessively.
2Reliability
If transmission diversity with phase shift patterns is applied, then bit error rates for ACK/NACK are reduced and diversity gain is maintained, but implementation complexity increases
Solution Approach 1:
The patent utilizes parameter changes by applying different phase shift patterns based on ACK/NACK status. When ACK/NACK is detected, a specific phase shift pattern is applied to the mapped coded UCI before transmission. This parameter modification (phase shifting) provides additional error protection and diversity gain without fundamentally changing the transmission structure, thus limiting the increase in implementation complexity.
3Reliability
If ACK/NACK differentiation is implemented, then packet loss is prevented and error rates are reduced, but coding and processing requirements increase
Solution Approach 1:
The patent applies partial action by implementing transmission diversity and phase shift patterns specifically for ACK/NACK bits rather than applying the same treatment to all control bits. This selective application provides excessive protection for the critical ACK/NACK information while avoiding the full computational overhead that would result from treating all control bits equally with maximum protection mechanisms.
Data Source
AI summary
A method for transmitting uplink control information (UCI) using a physical uplink control channel (PUCCH) transmit diversity scheme is described. A UCI is coded with a Forward Error Correction code to obtain a coded UCI. The coded UCI is mapped to quadrature phase shift keying (QPSK) symbols to obtain a mapped coded UCI. A phase shift pattern is selected. A phase shift from the phase shift pattern is applied to the mapped coded UCI based on an acknowledge/negative-acknowledge (ACK/NACK) to obtain a phase shifted mapped coded UCI. The mapped coded UCI is sent using a PUCCH resource on a first antenna. The phase shifted mapped coded UCI is sent using a PUCCH resource on a second antenna.