5G Reference Signal Sequence Initialization Value Limiting
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Solution Overview
Problem
The increase in the number of base stations and subcarrier spacing in 5G NR networks poses challenges for generating reference signals for channel estimation, as current techniques are inadequate due to initialization sequence length issues with pseudo-random number generators.
Innovation Solution
A method is introduced to limit the initialization value to be less than a predetermined positive integer M, mapping it into an initialization sequence of a fixed length L, and using a pseudo-random number generator to generate a pseudo-random number sequence for producing a reference signal sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of base stations increases to provide broader coverage in 5G NR networks, then the area coverage and network capacity are improved, but the initialization value for pseudo-random number generation becomes too large (greater than 2^31), resulting in initialization sequence lengths that exceed the generator's capabilities
Solution Approach 1:
The patent applies parameter changes by modifying the initialization value calculation to use only the lower 31 bits (applying modulo 2^31 operation). This transforms the initialization parameter from a potentially large value (when many base stations are present) into a constrained value that fits within the pseudo-random number generator's capacity, while still maintaining uniqueness across different base stations through the use of cell ID and slot index parameters.
2Speed
If the subcarrier spacing increases to support higher data rates in 5G NR networks, then the transmission speed is improved, but the initialization value for reference signal generation becomes excessively large, exceeding the pseudo-random number generator's processing capability
Solution Approach 1:
The patent resolves this contradiction by changing the parameter representation method - instead of using the full subcarrier spacing value which can be very large, the system uses the lower 31 bits of the initialization value derived from cell ID and slot index. This parameter transformation maintains the necessary differentiation for various subcarrier spacing configurations while keeping the actual generator input within acceptable bounds.
3Quantity of substance
If the initialization value is kept large to uniquely identify each base station in a dense network, then the network capacity and identification capability are improved, but the pseudo-random number generator cannot process initialization sequences longer than its fixed length L
Solution Approach 1:
The patent applies parameter changes by using a composite initialization value formed from multiple smaller parameters (cell ID and slot index) rather than a single large parameter. The cell ID provides base station identification while the slot index provides time-domain differentiation. By combining these through a modular arithmetic operation (modulo 2^31), the system achieves unique identification for many base stations while keeping the initialization value within the generator's processing capability.
Solution Approach 2:
The patent segments the initialization value into multiple components: cell ID (identifying the base station) and slot index (identifying the time slot). This segmentation allows the system to maintain uniqueness across many base stations and time slots while each individual component remains small enough that their combination (through modulo operation) stays within the pseudo-random number generator's capacity.
Data Source
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AI summary
A method and apparatus for generating a reference signal sequence for performing channel estimation. In one embodiment, the method includes: determining an initialization value; limiting the initialization value to be less than a predetermined positive integer M to provide a limited initialization value; mapping the limited initialization value into an initialization sequence having a predetermined number L of sequence values; providing the initialization sequence to a pseudo-random number generator to generate a pseudo-random number sequence; and generating the RS sequence based on the PRNS.