PUCCH Resource Selection for Semi-Persistent Scheduling in LTE Terminals
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Solution Overview
Problem
In 3GPP LTE systems, terminals face challenges in receiving downlink assignment control signals, leading to discontinuous transmission of ACK/NACK signals and reduced uplink data quality due to resource occupancy by response signals, especially when configured with 2 CCs and supporting up to 2 TBs, resulting in a lack of PUCCH resources during semi-persistent scheduling.
Innovation Solution
A terminal apparatus and base station apparatus are configured to communicate using a component carrier group with two downlink component carriers and one uplink component carrier, employing a control information receiving section, downlink data receiving section, error detecting section, and response controlling sections to manage response signals using a selected uplink control channel index associated with transmission power control information, ensuring efficient PUCCH resource utilization during semi-persistent scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the terminal is configured with 2 CCs and transmission mode supporting up to 2 TBs, then the downlink data transmission capacity is improved, but the PUCCH resources become insufficient during semi-persistent scheduling
Solution Approach 1:
The patent applies dynamics by making the PUCCH resource selection adaptive based on the scheduling type. The terminal dynamically switches between two different PUCCH resource sets: one for dynamic scheduling and another for semi-persistent scheduling. This dynamic adaptation allows the system to optimize resource usage according to the specific scheduling mode, resolving the resource conflict that arises when supporting both high-capacity transmission modes and semi-persistent scheduling simultaneously.
Solution Approach 2:
The patent segments the PUCCH resources into distinct sets based on the scheduling type. Instead of using a single unified PUCCH resource pool, the system divides resources into separate segments: one segment for dynamic scheduling responses and another segment for semi-persistent scheduling responses. This segmentation eliminates resource conflicts by ensuring that each scheduling type has dedicated resources, thereby maintaining full downlink capacity while ensuring sufficient PUCCH resources for semi-persistent scheduling.
2Adaptability or versatility
If the base station transmits activation indication for semi-persistent scheduling, then the scheduling control flexibility is improved, but the signaling overhead increases
Solution Approach 1:
The patent applies universality by designing the PUCCH resource indication mechanism to serve multiple functions. The same PUCCH resource indication field in the downlink assignment control information is used both to indicate the PUCCH resource for dynamic scheduling responses and to indicate the PUCCH resource for semi-persistent scheduling activation confirmations. This multi-functional design allows the system to maintain scheduling flexibility while minimizing signaling overhead, as the same signaling structure serves multiple purposes without requiring additional dedicated signaling fields.
3Ease of operation
If the terminal performs blind-determination on PDCCH control information, then the terminal can acquire control information without prior knowledge, but the determination time and processing complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring the terminal with multiple candidate PUCCH resource sets corresponding to different scheduling types and transmission modes. Instead of performing extensive blind determination at the time of response transmission, the terminal has already identified and stored the appropriate PUCCH resources in advance based on the received downlink assignment control information. This preliminary identification significantly reduces the determination time and processing complexity when actually transmitting the ACK/NACK response, as the terminal simply needs to select from the pre-identified resources rather than performing full blind search.
Data Source
AI summary
The present invention pertains to a terminal device, which, when ARQ is used for communication that uses an uplink unit band and a plurality of downlink unit bands associated with the uplink unit band, and when a transmission mode that supports up to 2 TB in a PCell is set in the terminal, is capable of reducing the amount of signaling from a base station while eliminating a lack of PUCCH resources when semi-permanent scheduling (SPS) is used in the PCell. A control unit in this device selects one value among values obtained by adding 1 to four PUCCH resource indexes, which have been preset for PUCCH resource 1 by the base station, on the basis of values for transmission power control information (TPC command for PUCCH) in a PDCCH, for which notification has been received at the start of SPS.