Coded Pseudorandom Sequences for Low Cross-Correlation Signaling
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Solution Overview
Problem
Current pseudorandom sequence generation techniques in wireless communication systems are limited in scalability, information capacity, and suffer from cross-correlation issues, particularly in higher frequency bands and increased cell/UE densities.
Innovation Solution
The described techniques involve segmenting information bits into bit groups, mapping them to symbols, encoding with error detection/correction codes, and applying orthogonal cover codes to generate pseudorandom sequences, which are then multiplexed and transmitted, supporting multi-stage randomization and improved auto-correlation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pseudorandom sequence generation techniques are used, then the system is simple to implement, but the sequences suffer from cross-correlation issues and are limited in information capacity
Solution Approach 1:
The information bits are segmented into multiple bit groups, with each group mapped to a respective symbol. This segmentation allows the system to generate multiple codewords from different segments, which are then multiplexed to form the final pseudorandom sequence. This approach reduces cross-correlation by distributing information across multiple independent segments while maintaining manageable complexity through systematic processing of each segment.
Solution Approach 2:
The patent introduces an additional dimension by applying encoding in the symbol domain rather than directly in the bit domain. By mapping bit groups to symbols and then encoding these symbols, the system transforms the problem from a one-dimensional bit sequence to a two-dimensional structure (bits→symbols→codewords), enabling better control over cross-correlation properties and information capacity.
2Loss of information
If more information is encoded in the pseudorandom sequence, then the information capacity increases, but the sequence generation becomes more complex
Solution Approach 1:
Information bits are divided into multiple bit groups that can be independently mapped to symbols and encoded. This segmentation allows the system to increase information capacity by utilizing multiple parallel encoding paths while keeping each individual encoding operation relatively simple and manageable.
Solution Approach 2:
The encoding apparatus is designed to perform multiple functions: it can encode different bit groups into different codewords, apply various encoding schemes (such as Reed-Solomon or convolutional coding), and multiplex these codewords into a unified pseudorandom sequence. This multi-functionality allows the same apparatus to handle increased information capacity without proportionally increasing complexity.
3Productivity
If pseudorandom sequences are used in higher frequency bands with increased cell/UE densities, then the communication capacity increases, but cross-correlation issues and interference worsen
Solution Approach 1:
By segmenting information into multiple bit groups and encoding them into separate codewords that are then multiplexed, the system reduces cross-correlation between different sequences. This is particularly important in high-density scenarios where multiple UEs transmit simultaneously, as the segmented structure ensures better orthogonality and reduced interference.
Solution Approach 2:
The patent changes key parameters of the pseudorandom sequence generation process, including the mapping from bit groups to symbols, the encoding scheme applied to each symbol, and the multiplexing strategy. These parameter changes enable the system to maintain low cross-correlation properties even when operating in high-frequency bands with increased cell and UE densities, thereby supporting higher communication capacity without proportionally increasing interference.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A wireless device may generate a coded pseudorandom using an encoder that implements error detection and/or error correction techniques. A bit sequence of information bits may be segmented into a plurality of bit groups, and each bit group may be mapped to a respective symbol to generate a plurality of ordered information symbols. The plurality of ordered information symbols may be encoded (e.g., by the encoder) to generate a plurality of codewords. Each codeword may be demapped to generate a plurality of sequences that are multiplexed to generate the pseudorandom sequence. A signal that is generated based on the pseudorandom sequence may be transmitted by the wireless device. In some examples, the wireless device may generate a reference signal based on orthogonal or pseudo-orthogonal random sequences generated by applying an orthogonal cover code to a pseudorandom sequence.