Scrambling Sequence Extension for Extended Physical-Layer Cell Identity Uniqueness
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Solution Overview
Problem
Current wireless communication systems face scrambling conflicts and collisions due to the limited physical-layer cell identity space, particularly when additional identities are needed to differentiate Macro cells and home eNodeBs, leading to non-unique scrambling sequences in extended PCI spaces.
Innovation Solution
The solution involves extending existing scrambling sequence generators to provide unique cell identities within an extended physical-layer cell identity space by increasing the number of scrambling sequences, including adding exponential factors to scrambling codes, and enabling options to select between original and extended search spaces, ensuring cell identity uniqueness without modifying legacy systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional physical-layer cell identities are added to differentiate Macro cells and home eNodeBs, then the ability to differentiate network nodes is improved, but scrambling sequence uniqueness deteriorates causing conflicts and collisions
Solution Approach 1:
The patent extends the PCI space from the original 504 identities to an extended space of 1008 identities by introducing an additional dimension - the extended PCI indicator bit. This allows the system to differentiate more network nodes while maintaining scrambling sequence uniqueness through the extended identity space.
Solution Approach 2:
The patent modifies the PCI parameter by introducing an extended PCI indicator that changes the interpretation of PCI values. When the indicator is set to a second value, PCI values in the range of 504 to 1007 are mapped to extended PCIs by subtracting 504, effectively expanding the parameter space while maintaining uniqueness.
2Quantity of substance
If the physical-layer cell identity space is extended beyond 504 identities, then the quantity of unique cell identities is improved, but the existing scrambling sequences become non-unique causing collisions
Solution Approach 1:
The patent segments the PCI space into two distinct ranges: original PCIs (0-503) and extended PCIs (504-1007). By segmenting the space and applying different mapping rules to each segment, the system can support more identities while maintaining scrambling sequence uniqueness through the extended indicator mechanism.
Solution Approach 2:
The extended PCI indicator acts as an intermediary element that mediates between the extended PCI values and the scrambling sequence generation. This indicator bit provides the necessary information to distinguish between original and extended PCIs, ensuring that scrambling sequences remain unique even in the extended space.
3Reliability
If scrambling sequences are extended to account for increased physical layer cell identities, then cell identity uniqueness in extended space is improved, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the extended PCI indicator and the mapping rules before scrambling sequence generation. The indicator is set in advance based on whether the PCI is original or extended, allowing the scrambling sequence generator to directly use the extended PCI value without complex runtime calculations, thus reducing actual processing complexity.
Data Source
AI summary
A method for wireless communications is provided. The method includes determining a set of physical layer cell identities and analyzing a current set of scrambling sequences. The method increases the current set of scrambling sequences to account for increases in the physical layer cell identities.