Block Spreading for Orthogonal Reference Signal Multiplexing
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently multiplexing reference signals from multiple transmitters, leading to mutual interference, which limits the number of simultaneously multiplexed signals that can be effectively transmitted.
Innovation Solution
The use of constant amplitude zero cyclic auto-correlation (CAZAC) sequences combined with block spreading allows for the orthogonal multiplexing of reference signals, enabling efficient resource utilization and separation of different transmitters, even when using identical baseline sequences, by employing distinct block-spreading sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional multiplexing methods are used for reference signals, then the system structure remains simple, but the number of simultaneously multiplexed signals is limited and mutual interference occurs
Solution Approach 1:
The reference signal transmission is segmented into multiple orthogonal components through block spreading. Each reference signal is spread across multiple resource elements using orthogonal block spreading sequences, allowing multiple signals to occupy the same time-frequency resources while maintaining orthogonality. This segmentation in the signal domain enables increased multiplexing capacity without causing mutual interference.
Solution Approach 2:
The patent introduces an additional orthogonal dimension through block spreading sequences. Instead of only using frequency and time dimensions for signal separation, the invention adds a fourth dimension using orthogonal block spreading codes. This dimensional expansion allows multiple reference signals to be multiplexed simultaneously without interference, significantly increasing the number of supportable signals.
2Quantity of substance
If more reference signals are multiplexed using traditional methods, then signal diversity increases, but resource utilization becomes inefficient and interference increases
Solution Approach 1:
Multiple reference signals are merged into the same time-frequency resources through orthogonal block spreading. Instead of allocating separate resources to each reference signal, the invention combines multiple signals in the same resource blocks, separated by orthogonal block spreading sequences. This merging approach dramatically improves resource utilization efficiency while supporting increased signal diversity.
3Object-affected harmful factors
If orthogonal multiplexing is implemented for multiple transmitters, then mutual interference is avoided, but the system complexity increases
Solution Approach 1:
Orthogonal block spreading sequences are applied preliminarily at the transmitter side before resource allocation. By pre-spreading reference signals with orthogonal sequences, the system establishes orthogonality in advance, preventing mutual interference before signals are transmitted. This preliminary action simplifies receiver processing, as demodulation can directly correlate with the known orthogonal sequences without complex interference cancellation.
Data Source
AI summary
Embodiments of the invention apply block spreading to transmitted signals to increase the number orthogonally multiplexed signals. The principle of the disclosed invention can be applied to reference signals, acknowledgement signals, and channel quality indication signals. In any given time interval, the set of transmitted signals is defined by two sequences: the baseline sequence, and the block spreading sequence. Different transmitters using the same baseline sequence can be identified by using different block spreading sequences.