MIMO-OFDMA Resource Allocation via Diagonal Matrix Decomposition

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Solution Overview

Problem

Current radio resource allocation methods for downlink mobile MIMO-OFDMA systems face challenges in balancing capacity and computation complexity, requiring a more efficient approach to allocate transmission power and subcarrier fractions while handling critical mobile channel conditions.

Innovation Solution

A novel method and system that utilize a proposed channel equalization scheme and resource allocation algorithm with linear complexity, involving matrix operations to generate a diagonal matrix, and a modified water-filling optimal power allocation scheme, to maximize sum capacity by determining transmission powers and subcarrier fractions efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional radio resource allocation methods are used to increase system capacity, then capacity improves, but computation complexity increases

Engineering Contradiction:
Improvesystem capacityVSAvoidcomputation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the radio resource allocation problem into two independent stages: first allocating subcarrier fractions to users, then allocating transmission powers across subcarriers. This segmentation transforms the complex joint optimization problem into simpler sequential problems, reducing computation complexity while maintaining high system capacity. The diagonal matrix decomposition further simplifies the channel matrix operations in each stage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces parameter transformations by converting the channel matrix into a diagonal matrix through unitary transformations. This parameter change simplifies the capacity calculation and optimization processes. Additionally, the patent uses water-filling power allocation and linear programming techniques to efficiently determine optimal transmission powers and subcarrier fractions, reducing computational burden while maximizing capacity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If more sophisticated allocation algorithms are implemented to handle mobile channel conditions, then capacity improves, but computation time increases

Engineering Contradiction:
ImprovecapacityVSAvoidcomputation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by pre-computing the diagonal matrix from the channel matrix and determining subcarrier fractions before final power allocation. This preliminary processing simplifies subsequent computations and reduces overall computation time. The diagonal matrix decomposition is performed once and reused in the power allocation stage, avoiding redundant calculations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex iterative optimization methods with more efficient mathematical techniques. Specifically, it uses diagonal matrix decomposition and water-filling algorithms that have closed-form solutions or converge faster than traditional iterative methods. The linear programming approach for subcarrier fraction allocation also provides more efficient computation compared to conventional methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8009598B2Method and system of radio resource allocation for mobile MIMO-OFDMA
Publication Date: 2011.08.30 XUESHAN TECH INC
  • US8009598B2 patent drawing
  • US8009598B2 patent drawing
  • US8009598B2 patent drawing

AI summary

This patent discloses a method and a system of radio resource allocation for a mobile MIMO-OFDMA system, the method comprising the steps of: generating a diagonal matrix according to a channel matrix; determining a sum capacity function associated with the diagonal matrix, a plurality of transmission powers, and a plurality of subcarrier fractions; performing a first subcarrier fraction allocation by maximizing the sum capacity function according to a predetermined user capacity condition; performing a first transmission power allocation according to the first subcarrier allocation; and performing a second subcarrier fraction allocation by maximizing the sum capacity function according to the first transmission power allocation and the predetermined user capacity condition.