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M-sequence generators create pseudorandom binary sequences used in 5G for scrambling and spreading techniques, which help in the security and efficiency of data transmission.
### Introduction
![](Pasted%20image%2020240715192412.png)
The diagram shows principle and application of pseudo-random sequences in 5G communications.
On the left, it details the mathematical rules for M-sequence generation used for scrambling in signal processing. The right side shows the practical implementation, integrating these sequences into various stages of coding, modulation, and mapping in a 5G system, highlighting key processes like polar coding, QPSK modulation, and resource element mapping to ensure efficient and secure data transmission.
### Implementation
![](Pasted%20image%2020240716115311.png)
A Linear Feedback Shift Register (LFSR) is a simple type of shift register, often used in digital circuits to generate pseudo-random binary sequences. These sequences are created by shifting bits through the register and using a linear function—typically an XOR operation on selected bits (taps)—to generate the input for the next shift. This setup allows LFSRs to produce long sequences of bits with desirable properties for applications such as cryptography, error detection, and spread spectrum communications.
Gold sequence, which is produced by two LFSRs generating m-sequences has good cross-correlation properties ( ideal for distinguishing multiple signals in communications. )
![](Pasted%20image%2020240716115955.png)
Diagram illustrates a Basic Software LFSR implementation of Linear Feedback Shift Register (LFSR) sequence generation using matrix-vector operations. This method processes data at a rate of **0.074 bits per cycle**, emphasizing compatibility with standard CPU architectures and simplicity in design.
![](Pasted%20image%2020240716111517.png)
**Vector Register Implementation**
The second diagram demonstrates a more advanced implementation using vector registers, leveraging a one-instruction solution for bit polynomial processing. This method significantly enhances performance, achieving a throughput of **7 bits per cycle**. By utilizing the parallel processing capabilities of modern CPUs.
### Result
The contrasting implementations of Linear Feedback Shift Registers (LFSR) demonstrate significant differences in performance and efficiency. The **Basic SW LFSR** approach processes data at a modest rate of **0.074 bits per cycle**. In contrast, the advanced vector register implementation dramatically increases throughput to **7 bits per cycle**, exploiting modern CPU capabilities for parallel processing.
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