Uplink Acknowledgement Transmission in Carrier-Aggregated Wireless Systems
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Solution Overview
Problem
In wireless communication systems, particularly in MIMO systems, there is a challenge in efficiently transmitting acknowledgement signals across multiple downlink carriers due to the complexity of managing and coordinating uplink acknowledgement signals in carrier-aggregated networks, which affects data stream decoding and overall network performance.
Innovation Solution
A subscriber station and base station system that derives uplink acknowledgement signal cyclic shift resource indices from control channel elements in multiple downlink carriers, allowing for coordinated acknowledgement signal transmission across multiple carriers, improving decoding efficiency and network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple downlink carriers are used for data transmission, then spectral efficiency is improved, but the complexity of managing uplink acknowledgement signals increases
Solution Approach 1:
The patent segments the uplink acknowledgement signal management by deriving separate cyclic shift resource indices for each downlink carrier. The first cyclic shift resource index is derived from control channel elements in the first downlink carrier, while the second cyclic shift resource index is derived from control channel elements in the second downlink carrier. This segmentation allows independent management of ACK/NACK resources per carrier, reducing overall system complexity while maintaining multi-carrier operation.
Solution Approach 2:
The patent introduces a new dimension for resource management by using cyclic shift resource indices derived from control channel element indices. Instead of managing acknowledgement resources in the traditional time-frequency domain only, the system adds a cyclic shift dimension that is directly linked to the control channel element allocation, enabling more efficient resource differentiation across multiple carriers.
2Productivity
If carrier aggregation is implemented to increase data rates, then throughput is improved, but the complexity of coordinating acknowledgement transmissions increases
Solution Approach 1:
The patent applies segmentation by assigning separate cyclic shift resource indices to acknowledgements for different downlink carriers. The first cyclic shift resource index corresponds to the first downlink carrier and the second cyclic shift resource index corresponds to the second downlink carrier. This segmentation simplifies coordination by allowing the receiver to independently identify and process acknowledgements from each carrier without complex cross-carrier coordination mechanisms.
Solution Approach 2:
The control channel element indices serve as intermediaries that link downlink carrier allocations to uplink acknowledgement resources. By deriving cyclic shift resource indices from control channel element indices, the system creates a natural mapping relationship that simplifies the coordination process, eliminating the need for separate resource allocation signaling for acknowledgements.
Data Source
AI summary
A system and method of uplink acknowledgement transmission. The wireless network implements carrier aggregation wherein a subscriber station may be allocated downlink resource blocks distributed over multiple downlink carriers. The subscriber station receives control channel elements from at least one base station on at least two downlink carriers. The subscriber station derives uplink acknowledgement signal cyclic shift resource indices for respective carriers from functions of the index of the control channel elements that have carried a downlink grant the respective downlink carrier. The subscriber station transmits N number of ACK/NACK symbols in at least one physical uplink channel resource.