4C-HSDPA Acknowledgment Signaling via HS-DPCCH Multiplexing
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently signaling acknowledgment status for multiple carriers in 4C-HSDPA, as prior methods do not adequately accommodate the increased number of downlink carriers, leading to suboptimal data transfer and acknowledgment processes.
Innovation Solution
The proposed solution involves utilizing the existing HS-DPCCH channel structure with a spreading factor of 128 to serially time-multiplex two 10-symbol codewords within the HARQ-ACK slot, allowing the UE to signal acknowledgment status for up to four downlink carriers, while selecting codewords from existing codebooks to maintain compatibility with pre-existing HSDPA and MIMO systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spreading factor of 256 is used to signal acknowledgment status for up to two carriers, then the existing HSDPA channel format is maintained, but the system cannot accommodate four downlink carriers in 4C-HSDPA
Solution Approach 1:
The acknowledgment signaling for four carriers is segmented into two separate 10-symbol codewords, each handling two carriers. The first codeword signals ACK/NACK/DTX for carriers 1-2, and the second codeword signals for carriers 3-4. This segmentation allows the system to accommodate four carriers while maintaining compatibility with existing HSDPA channel formats that were designed for two carriers.
Solution Approach 2:
The patent introduces a time-division dimension by transmitting the two 10-symbol codewords serially within the HARQ-ACK slot. Instead of attempting to encode all four carriers in a single spatial/codeword dimension, the solution uses the time dimension to multiplex two separate acknowledgment messages, effectively doubling the carrier capacity without increasing the complexity of individual codeword structures.
2Adaptability or versatility
If new channel formats and codewords are introduced to accommodate four carriers, then acknowledgment signaling for 4C-HSDPA is enabled, but compatibility with pre-existing HSDPA systems is reduced
Solution Approach 1:
The HS-DPCCH channel structure is designed to serve multiple functions: it can transmit a single 10-symbol codeword for legacy two-carrier HSDPA systems, or it can transmit two 10-symbol codewords serially for 4C-HSDPA systems. The existing codebooks and channel formats are reused, allowing the same physical layer structure to accommodate both legacy and advanced multi-carrier scenarios without requiring separate dedicated formats.
Solution Approach 2:
The system dynamically adapts its acknowledgment signaling mode based on the number of active downlink carriers. When two or fewer carriers are active, the UE uses the traditional single-codeword format for backward compatibility. When four carriers are active, the UE switches to the dual-codeword serial transmission mode. This dynamic behavior allows seamless coexistence of legacy and 4C-HSDPA operations.
3Quantity of substance
If serial time-multiplexing of two 10-symbol codewords is used, then acknowledgment status for four carriers can be signaled, but the transmission time within the HARQ-ACK slot increases
Solution Approach 1:
The HARQ-ACK slot is structured to periodically accommodate the serial transmission of two 10-symbol codewords. Each codeword is transmitted in a dedicated time period within the slot, with the first codeword occupying the initial portion and the second codeword occupying the subsequent portion. This periodic structure ensures that the extended transmission time is organized and predictable, allowing the system to accommodate four carriers while maintaining timing synchronization.
Data Source
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AI summary
Techniques for signaling acknowledgment status (e.g., ACK, NACK, or DTX) for up to four detected carriers according to 4C-HSDPA. In an exemplary embodiment, an ACK slot of an HS-DPCCH channel utilizes spreading factor 128 to accommodate two 10-symbol codewords per slot. The codewords may be dual-carrier codewords, enabling the acknowledgment status of up to four carriers to be signaled in each slot. A DTX-DTX codeword may be further provided to signal no detection of two carriers assigned to the same codeword. In an alternative exemplary embodiment, a codeword signaling acknowledgment status for two carriers may be repeated twice over a single slot.