Carrier-Frequency Interleaving for Correlated Bit Separation
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Solution Overview
Problem
As communication systems employ encoders with increasing constraint lengths, existing interleaving schemes struggle to effectively separate encoded bits to prevent noise and interference distortion, particularly in systems with multiple carrier frequencies.
Innovation Solution
The proposed interleaving scheme assigns encoded bits to carrier frequencies based on a round-robin method and utilizes a look-up table to ensure that each bit has a constant remainder when divided by the number of carrier frequencies, maximizing the distance between bits assigned to each carrier frequency, thereby ensuring that highly correlated bits are transmitted on separate symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interleaving schemes are used, then the system can handle basic encoding requirements, but encoded bits are not sufficiently separated when encoder constraint length increases
Solution Approach 1:
The patent changes the interleaving parameter from conventional methods to a round-robin assignment method where bits are assigned to carrier frequencies based on their index modulo the number of carrier frequencies. This ensures that bits separated by the constraint length K are assigned to different carrier frequencies, achieving sufficient separation without increasing system complexity.
Solution Approach 2:
The patent segments the encoded bit stream by dividing it into groups that are assigned to different carrier frequencies using the round-robin method. This segmentation ensures that correlated bits are distributed across different frequency channels, preventing noise and interference from affecting multiple correlated bits simultaneously.
2Productivity
If encoded bits are transmitted on the same transmission symbol, then transmission efficiency is maintained, but noise and interference impact correlated bits simultaneously
Solution Approach 1:
The patent changes the assignment parameter from conventional sequential assignment to round-robin modulo assignment, ensuring that bits determining the same transmission symbol are drawn from different encoded bit positions. This maintains transmission efficiency while ensuring that correlated bits are not transmitted on the same symbol, thereby reducing the impact of noise and interference.
3Reliability
If the separation distance between encoded bits is increased, then noise and interference impact is reduced, but the interleaving complexity increases
Solution Approach 1:
The patent uses the round-robin assignment method with modulo arithmetic to achieve uniform separation of encoded bits across carrier frequencies. This mathematical approach ensures that bits separated by constraint length K are assigned to different frequencies without requiring complex interleaving logic, thus achieving noise resistance without excessive complexity.
Data Source
AI summary
An interleaver and scheme for interleaving in which highly correlated bits are maximally separated. The scheme involves interleaving a set of bits to be delivered to a modulation system that utilizes a quantity of N carrier frequencies. A first block of N consecutive bits is assigned to each of N bins, on a one-bit-per-one-bin basis. The aforementioned assignment proceeds in a particular sequence. A second block of N consecutive bits is assigned to each of the N bins, on a one-bit-per-one-bin basis. The second block is assigned in the same sequence the first block was assigned. The second block is consecutive to the first block.