Downlink Control Information Mapping for Fair Power Saving Access
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Solution Overview
Problem
In existing 5G NR systems, the power saving signal's Group DCI often prioritizes power saving information for terminal devices at the front of the order, leading to unequal chances for devices at the back to obtain this information, which is not conducive to optimal power saving functionality.
Innovation Solution
A method where a network device determines DCI with indication information and time domain information to randomly distribute power saving information blocks among terminal devices, using cyclic shifts to ensure equal chances for all devices to obtain power saving information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Group DCI prioritizes power saving information for terminal devices at the front of the order, then information delivery efficiency for front devices is improved, but information access fairness among all terminal devices deteriorates
Solution Approach 1:
The patent applies dynamics by making the mapping relationship between terminal devices and information blocks change over time. Specifically, the network device uses different mapping methods (such as cyclic shifts) at different time moments to dynamically adjust which terminal devices can obtain power saving information from the Group DCI. This resolves the contradiction by ensuring both efficient information delivery (when needed) and fair access opportunities (rotating through different devices over time).
Solution Approach 2:
The patent implements periodic action through the use of cyclic shifts that rotate through different terminal devices at regular intervals. The mapping relationship between terminal devices and information blocks is periodically changed using these cyclic shifts, ensuring that over time, all terminal devices in the group have equal opportunities to obtain power saving information. This periodic rotation resolves the fairness issue while maintaining efficient information delivery within each period.
2Loss of information
If Group DCI includes information blocks for all terminal devices, then information completeness is improved, but DCI message length increases
Solution Approach 1:
The patent applies partial action by including only a subset of terminal device information blocks in each Group DCI message rather than all devices. The network device selectively includes information blocks for certain terminal devices based on the mapping relationship, which changes over time. This ensures that while not all devices receive information in every message (partial action), all devices receive complete information over time as the mapping rotates, thus resolving the contradiction between message length and information completeness.
Solution Approach 2:
The patent segments the complete set of terminal device information blocks into multiple smaller groups that are transmitted at different time moments. Each Group DCI message contains only a segment of the total information blocks, determined by the current mapping relationship. This segmentation reduces individual message lengths while ensuring that over time, all segments are transmitted, providing complete information to all terminal devices.
3Device complexity
If Group DCI uses fixed mapping order for terminal devices, then implementation complexity is reduced, but information access fairness deteriorates
Solution Approach 1:
The patent resolves this contradiction by introducing a dynamic yet systematic mapping approach. Instead of a completely fixed mapping, the system uses predetermined rules (such as cyclic shift formulas) that automatically adjust the mapping relationship over time. This maintains relatively low implementation complexity (using simple mathematical operations) while achieving fair information access (as all devices rotate through different positions in the mapping).
Solution Approach 2:
The patent changes the mapping parameter (the offset or shift value) over time to achieve fair information distribution. By systematically varying this parameter according to predetermined rules, the system transforms a static, unfair mapping into a dynamic, fair mapping without significantly increasing implementation complexity. The parameter changes follow simple patterns that are easy to compute and implement.
Data Source
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AI summary
A method for sending downlink control information DCI and an apparatus are provided. The method includes: For DCI that is sent to N terminal devices and that includes power saving information, a network device may determine, based on b1 terminal devices indicated in indication information and time domain information of the DCI, m1 information blocks carried in the DCI. In this way, a chance for each terminal device in the N terminal devices to obtain the power saving information may be almost equal without much difference, thereby giving full play to a power saving function of a power saving signal.