Pilot Sequence Multiplexing for LTE Error Control
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Solution Overview
Problem
Current radio communication systems, such as 3GPP LTE, face inefficiencies in bandwidth utilization due to the need for separate pilot sequences and ACK/NAK signals for error control, which occupy valuable network resources.
Innovation Solution
The method involves generating and using two pilot sequences, one for acknowledgement and one for negative acknowledgement, to convey error control information within existing pilot signals, thereby eliminating the need for separate ACK/NAK signals and multiplexing acknowledgement signaling bits with channel quality indicator (CQI) bits into a common sub-frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate pilot sequences and ACK/NAK signals are used for error control, then error control functionality is provided, but bandwidth utilization deteriorates due to occupying valuable network resources
Solution Approach 1:
The patent combines ACK/NAK signaling functionality with existing pilot sequences by modulating the pilot sequences to carry acknowledgment information. Instead of transmitting separate ACK/NAK signals, the system embeds error control signaling within the pilot sequences themselves, thereby eliminating dedicated overhead for acknowledgments while maintaining reliable error control.
Solution Approach 2:
The patent makes pilot sequences multi-functional by enabling them to serve both their traditional purpose (channel estimation and synchronization) and error control signaling simultaneously. The pilot sequences are designed to carry dual information: channel state information and acknowledgment status, thereby reducing the need for separate signaling channels.
2Loss of information
If separate ACK/NAK signals are transmitted, then error control information is conveyed, but network resource overhead increases
Solution Approach 1:
The patent merges error control information transmission with existing pilot sequence transmission. The acknowledgment bits are mapped to specific resource elements within the pilot sequence structure, allowing simultaneous conveyance of channel information and error control status without requiring additional dedicated resources for ACK/NAK signaling.
Solution Approach 2:
The patent extracts the acknowledgment signaling function from separate dedicated signals and integrates it into the existing pilot sequence structure. By removing the need for separate ACK/NAK signal transmission and embedding the functionality within pilots, the system eliminates redundant overhead while preserving complete error control information.
3Loss of energy
If pilot sequences are used for both channel estimation and ACK/NAK signaling, then bandwidth efficiency improves, but signal detection complexity increases
Solution Approach 1:
The patent segments the pilot sequence structure to accommodate multiple functions. Specific resource elements within the pilot sequence are designated for channel estimation while other elements carry acknowledgment information. This segmentation allows the receiver to separately process channel estimation and ACK/NAK detection using dedicated processing paths, thereby managing complexity while maintaining bandwidth efficiency.
Solution Approach 2:
The patent introduces intermediate processing stages that facilitate the separation of functions within the combined pilot structure. The receiver first performs channel estimation using designated pilot elements, then uses the estimated channel to decode the embedded acknowledgment information from other pilot elements. This intermediary processing approach simplifies the overall detection complexity by breaking down the multi-functional signal into manageable processing steps.
Data Source
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AI summary
An approach is provided for an efficient control signaling associated with an error control scheme. A determination is made whether data has been properly received according to an error control scheme. A first pilot sequence representing an acknowledgement is generated if the data is properly received. A second pilot sequence representing a negative acknowledgement is generated if the data is not properly received. A frame including either the first pilot sequence or the second pilot sequence is output.