Terminal Device Secondary Cell Activation Timing
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Solution Overview
Problem
There is a lack of a concrete method for efficiently transmitting a physical uplink control channel in a secondary cell, which is a serving cell other than a primary cell in LTE communication systems.
Innovation Solution
A terminal device is designed with a measurement unit to derive channel state information and a transmission unit to transmit HARQ-ACK and channel state information reporting on physical uplink control and shared channels, along with a MAC layer processing unit to activate secondary cells by applying actions related to channel state information reporting and monitoring physical downlink control channels, optimizing communication through multiple cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a terminal device transmits channel state information reporting for multiple secondary cells simultaneously, then the communication efficiency through multiple cells is improved, but the device complexity and processing overhead increase
Solution Approach 1:
The patent segments the transmission of channel state information by separating it into different time slots and physical channels. Specifically, it divides the reporting into periodic reports on PUCCH/PUSCH and aperiodic reports triggered by MAC control elements, allowing the terminal to process and transmit CSI for multiple secondary cells in an organized, time-division manner rather than simultaneously, thus reducing processing overhead while maintaining communication efficiency.
Solution Approach 2:
The patent implements preliminary action by having the terminal pre-configure channel state information reporting parameters and resources before actual transmission. The MAC control element mechanism allows the network to pre-establish reporting rules for multiple secondary cells, so when activation occurs, the terminal can immediately follow predetermined reporting patterns without complex real-time decision-making, reducing processing overhead.
2Productivity
If the terminal device activates multiple secondary cells for simultaneous transmission and reception, then the data throughput is improved, but the power consumption and processing load increase
Solution Approach 1:
The patent applies dynamics by implementing flexible activation and deactivation of secondary cells based on network conditions and traffic requirements. The MAC control element mechanism allows dynamic switching between active and inactive states for secondary cells, enabling the terminal to activate only the necessary number of cells at any given time rather than maintaining all cells in a high-power state, thus balancing data throughput with power consumption.
3Productivity
If the terminal device transmits HARQ-ACK and channel state information on the physical uplink control channel in a secondary cell, then the control channel utilization is improved, but the reliability of control information transmission may be compromised
Solution Approach 1:
The patent uses the MAC control element as an intermediary mechanism to coordinate the transmission of HARQ-ACK and channel state information. Rather than directly transmitting all control information on the physical uplink control channel simultaneously, the MAC layer mediates by triggering aperiodic CSI reports and managing the timing and content of transmissions, ensuring that critical control information is transmitted reliably while still utilizing the secondary cell's uplink control channel effectively.
Data Source
AI summary
When a terminal device receives a MAC CE indicating activation of a second cell in subframe n and an action of monitoring a PDCCH for a first cell is not applied in subframe n+8, an action related to CSI reporting for the second cell on a PUCCH is applied in a subframe that is no earlier than subframe n+8 and in which an action of monitoring the PDCCH for the first cell is applied. When the terminal device receives the MAC CE indicating activation of the second cell in subframe n, the action related to the CSI reporting for the second cell on the PUCCH is applied in subframe n+8, irrespective of whether the action of monitoring the PDCCH for the first cell is applied in subframe n+8.