Uplink Control Information Mapping for Latency and Power Trade-offs
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently allocating and transmitting uplink control information, particularly in reducing latency for services sensitive to it, while maintaining power efficiency and supporting varying transmission time intervals (TTIs).
Innovation Solution
The method involves mapping and transmitting uplink control information using a combination of short and normal TTIs, allowing for flexible resource allocation and piggybacking UCI on PUSCH, with specific rules for CQI/PMI and ACK/NACK resource mapping to optimize performance across different TTI lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If short TTI is used for latency-sensitive services, then latency is reduced, but power consumption increases and resource allocation complexity increases
Solution Approach 1:
The system dynamically adjusts TTI length based on service requirements, using short TTI for latency-sensitive services and normal TTI for other services. This dynamic adaptation allows the system to optimize latency performance when needed while avoiding unnecessary power consumption for services that do not require short TTI, thus resolving the contradiction between latency reduction and power consumption.
2Loss of time
If short TTI is used for latency-sensitive services, then latency is reduced, but device complexity increases
Solution Approach 1:
The system segments resource allocation by creating separate resource pools for short TTI and normal TTI operations. Different resource allocation rules and parameters are defined for each TTI type, allowing independent optimization and management. This segmentation simplifies the overall complexity by organizing resource allocation into distinct, manageable segments rather than requiring a single complex allocation mechanism for all TTI types.
3Loss of information
If uplink control information is mapped onto time-frequency resources, then control information transmission is enabled, but resource efficiency decreases when uplink reference signals are present
Solution Approach 1:
The system applies different resource allocation strategies based on the local characteristics of each subframe. When uplink reference signals are present in a subframe, the system adjusts the resource allocation for uplink control information to account for the reference signal occupancy, thereby optimizing resource efficiency locally in each subframe while ensuring reliable control information transmission.
Data Source
Figure 1~1(b)
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AI summary
A method for mapping, as uplink data channel resource, uplink control information for a terminal configured to support multiple transmission time interval (TTI) lengths in a wireless communication system, according to one embodiment of the present invention, wherein the method is carried out by the terminal, comprises the steps of: mapping an encoding symbol for a rank indicator (RI) on each resource element, in an ascending order of a frequency index beginning with a resource element of the minimum frequency index, from on a second symbol adjacent to a first symbol onto which an uplink reference signal is mapped in an uplink data channel resource in a TTI having a specific length from the multiple TTI lengths; and mapping an encoding symbol for a channel quality indicator (CQI) or a precoding matrix indicator (PMI) on each of the resource elements, in an ascending order of the frequency index beginning with the resource element of the minimum frequency index or in a descending order of the frequency index beginning with a resource element of the maximum frequency index, from on a specific symbol of the uplink data channel resource.