HARQ Feedback Cyclic Shift Mapping for Unicast Multicast Differentiation
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Solution Overview
Problem
Current 5G solutions fail to differentiate acknowledgement feedback for unicast and multicast transmissions, leading to confusion in network nodes, and existing methods to address this require additional uplink resources, which is inefficient.
Innovation Solution
A method where a wireless device uses different cyclic shifts of a base sequence, such as CAZAC, to map acknowledgement feedback for unicast and multicast transmissions, allowing joint transmission in the same uplink control channel resources, enabling clear differentiation without increasing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If separate acknowledgement feedback channels are used for unicast and multicast transmissions, then differentiation between feedback types is improved, but uplink channel overhead increases
Solution Approach 1:
The patent merges the acknowledgement feedback channels for unicast and multicast transmissions into a single shared channel. By using cyclic shift differentiation of the same base sequence, the system combines multiple feedback types into one channel resource, eliminating the need for separate dedicated channels while maintaining clear differentiation between unicast and multicast feedback through the cyclic shift indicators.
Solution Approach 2:
The patent changes the parameter of the base sequence by introducing cyclic shifts as a differentiation mechanism. Instead of using separate physical channels, the system varies the cyclic shift parameter of the same base sequence to represent different feedback types (unicast vs. multicast), thereby achieving differentiation without additional channel resources.
2Productivity
If cyclic shift mapping is used for joint acknowledgement transmission, then resource utilization is improved, but complexity of feedback configuration increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the cyclic shift mapping table that associates specific cyclic shifts with unicast/multicast feedback combinations. This pre-established mapping configuration allows the wireless device to directly translate feedback states into cyclic shift values without complex real-time processing, thereby achieving efficient resource utilization while managing configuration complexity through standardized mapping rules.
Data Source
AI summary
Acknowledgement feedback is conveyed to a network node for unicast and multicast transmissions received by a wireless device. The wireless device configures uplink control channel resources responsive to an uplink channel format indicated by an uplink channel format indicator. Each possible ACK or NAK combination for the unicast and multicast transmissions maps to a different cyclic shift of a base sequence defined according to the uplink control channel format. The wireless device receives a unicast transmission and a multicast transmission. Further, when in a joint acknowledgement mode, the wireless device configures acknowledgement feedback for the received unicast and multicast transmissions according to the cyclic shift mapping and jointly transmits the acknowledgement feedback for both the received unicast transmission and the received multicast transmission to the network node in an acknowledgement time slot.