SLC-Based Integer Forcing Receiver for 2M-QAM Decoding

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Solution Overview

Problem

In 5G communication systems, the use of 2M-QAM modulation schemes poses challenges for integer forcing receivers due to the difficulty in directly applying modulation schemes with prime orders, leading to inefficiencies in decoding and increased noise levels.

Innovation Solution

Implementing a single level coding (SLC)-based integer forcing (IF) scheme that determines codewords and applies natural labeling to coded bits, using a posteriori probability (APP) and log likelihood ratio (LLR) calculations to improve decoding efficiency and reduce noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If MLC-based 2M-QAM symbol is used, then the modulation scheme can be applied to actual systems, but the code length decreases as modulation order increases

Engineering Contradiction:

Improveapplicability to actual systemsVSAvoidcode length

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the modulation process into multiple levels (first level and second level coding) where each level handles different aspects of the modulation. This segmentation allows the system to maintain adequate code lengths at each level while achieving high-order modulation, resolving the contradiction between adaptability and code length.

Inventive Principle:

Principle #1Segmentation

2Reliability

If integer forcing receiver is used, then maximum diversity can be attained, but decoding becomes difficult with 2M-QAM modulation

Engineering Contradiction:

Improvediversity gainVSAvoiddecoding difficulty

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent divides the decoding process into two separate levels: first level decoding handles the primary codeword extraction while second level decoding refines the solution. This segmentation makes the integer forcing decoding process more manageable and less difficult while maintaining maximum diversity benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary signal processing and equalization before the actual decoding step. By preparing the received signal in advance through integer forcing equalization and calculating preliminary metrics, the subsequent decoding operation becomes easier and more efficient.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If multiple level coding is implemented, then prime order modulation can be used, but implementation complexity increases with encoder and decoder for each bit-level

Engineering Contradiction:

Improvemodulation scheme flexibilityVSAvoidencoder and decoder implementation

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the encoding and decoding operations into a unified framework where the same processing structure is used at both transmitter and receiver. This consolidation reduces implementation complexity while maintaining the flexibility of prime order modulation schemes.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10461890B2Apparatus and method for processing signal in wireless communication system

Publication Date: 2019.10.29 SAMSUNG ELECTRONICS CO LTD

AI summary

The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system for supporting higher data rates Beyond 4th-Generation (4G) communication systems such as Long Term Evolution (LTE). A method for operating a receiver in a wireless communication system may include: receiving a signal from a transmitter; performing Integer Forcing (IF) equalization on the received signal; determining a log LikeLihood Ratio (LLR) value of each bit by using a posteriori probability of each bit for the signal determined based on an equalization matrix and a likelihood value for the signal; and decoding the signal by using the LLR value.