Uplink Control Channel Location Determination via MCS Mapping
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Solution Overview
Problem
In OFDMA-based communication systems, there is a need to coordinate uplink control signaling for user equipments (UEs) without explicit downlink control signaling, to avoid overhead and increase system throughput.
Innovation Solution
User equipments independently determine the signaling locations of uplink control information related to downlink data packet transmissions by utilizing a modulation and coding scheme (MCS) determined from channel quality indicator (CQI) feedback, with a control channel structure that includes a fixed-sized field (Cat0) indicating the size of the control channel and MCS regions, allowing UEs to implicitly determine their resource allocation for ACK/NAK and CQI transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explicit downlink control signaling is used to coordinate uplink control signaling, then reliability of control information transmission is improved, but overhead increases and system throughput decreases
Solution Approach 1:
User equipments independently determine their own signaling locations for uplink control information based on pre-configured rules and received downlink data packet information, without requiring explicit downlink control signaling coordination. This self-determination mechanism eliminates the need for additional control overhead while maintaining reliable control information transmission.
Solution Approach 2:
The system pre-configures mapping relationships between downlink data packet resource units and uplink control signaling resource units before actual transmission. User equipments use these pre-established mappings to determine signaling locations in advance, eliminating the need for real-time explicit control signaling and reducing overhead.
2Ease of operation
If explicit downlink control signaling is used to allocate resources for uplink control information, then ease of operation is improved, but productivity decreases
Solution Approach 1:
User equipments autonomously determine their signaling resource allocations based on pre-configured mapping rules and the downlink data packets they receive. This self-service approach eliminates the need for explicit resource allocation control signaling, thereby increasing downlink system throughput while maintaining operational simplicity through standardized mapping procedures.
Solution Approach 2:
Resource mapping relationships are pre-established between downlink data packet resource units and uplink control signaling resource units. User equipments apply these predetermined mappings to determine their signaling resources, simplifying the operation while eliminating the overhead that would otherwise reduce productivity.
3Reliability
If control channel size is increased to accommodate more control information, then reliability is improved, but overhead increases
Solution Approach 1:
The control channel includes a fixed-sized field that pre-indicates the total number of resource units allocated for uplink control signaling. This preliminary indication allows user equipments to determine their signaling locations without requiring additional dynamic control overhead, maintaining reliability while controlling the total control channel size.
Solution Approach 2:
The uplink control signaling resources are segmented into multiple resource units, each associated with specific downlink data packets. User equipments independently select their signaling resource units based on the downlink packets they received, distributing control information across multiple segments rather than requiring a single large control channel, thereby reducing overall overhead.
Data Source
AI summary
Embodiments of the invention provide methods for user equipments to implicitly determine the location for the transmission of uplink control signaling information, that is in response to downlink data packet transmissions, using information that is already available through the downlink control signaling for the respective downlink scheduling assignments. No additional explicit downlink control signaling is required for the transmission of the above uplink control signaling from each user equipment.