Network Coding Node Resource Allocation for Asymmetric Links

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Solution Overview

Problem

Existing bidirectional network coding systems face inefficiencies due to link asymmetry, leading to underutilization of capacity, delays, and increased complexity, particularly when handling different modulation schemes on Up-Link and Down-Link channels.

Innovation Solution

A network coding node that estimates and allocates resource elements based on the number of bits per resource element from each node, ensuring equal allocation for network coding operations across both nodes, thereby avoiding underutilization and delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional bidirectional relaying is used to exchange data between two end-users via a third node, then data exchange can be completed, but a total of 4 transmissions are needed which reduces system capacity utilization

Engineering Contradiction:

Improvedata exchange efficiencyVSAvoidtransmission resource consumption

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent merges the data transmission paths by having both end-users transmit their data to the relay node simultaneously in the first time slot, and the relay node combines both data streams into a single network-coded signal that is broadcast to both end-users in the second time slot. This merging of transmission paths reduces the total number of transmissions from 4 to 3, improving productivity while reducing resource consumption.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If link asymmetry is present in bidirectional network coding systems with different modulation schemes on Up-Link and Down-Link channels, then the system can adapt to different channel conditions, but it leads to underutilization of capacity, delays, and increased complexity

Engineering Contradiction:

Improvemodulation scheme flexibilityVSAvoidresource allocation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent explicitly addresses link asymmetry by allowing different modulation schemes (e.g., QPSK, 16QAM, 64QAM) on Up-Link and Down-Link channels. The relay node performs demodulation using the appropriate modulation scheme for each link type, enabling the system to adapt to different channel conditions while maintaining efficient resource utilization through proper resource element allocation.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the parameter of modulation order to adapt to different link conditions. By supporting multiple modulation schemes (QPSK with 2 bits/symbol, 16QAM with 4 bits/symbol, 64QAM with 6 bits/symbol), the system can optimize transmission for each link's channel quality while the resource allocation mechanism ensures proper matching of resource elements to the actual data rates.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If link asymmetry exists with different modulation schemes, then channel adaptation is possible, but underutilization of link capacity occurs

Engineering Contradiction:

Improvechannel adaptation capabilityVSAvoidlink capacity utilization

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements feedback mechanisms where the relay node estimates the number of bits per resource element for each link based on the modulation schemes being used. This feedback information is used to properly allocate resource elements in subsequent transmissions, ensuring that the allocated resources match the actual data rates and achieving full link capacity utilization while maintaining channel adaptation.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If link asymmetry with different modulation schemes is used, then the system can handle diverse channel conditions, but delays are introduced

Engineering Contradiction:

Improvemodulation diversity supportVSAvoiddata exchange delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent performs preliminary estimation of the number of bits per resource element for each link before allocating resource elements. By estimating the data rates based on the modulation schemes in advance and allocating the appropriate number of resource elements accordingly, the system avoids delays that would result from mismatched resource allocation or the need for retransmissions.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9231812B2Method and arrangement for resource allocation for coded multidirectional relaying

Publication Date: 2016.01.05 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

The present invention relates to a method and a network coding node for resource allocation applicable to multi-directional network coding in an exchanging system. By estimating the number of bits per resource element (steps 402, 404) on uplink channels to a network coding node (200, 304, 504, 604), the number of resource elements for the sending on said uplinks is determined (step 410) to fully utilize the resources, i.e. such that link underutilization is avoided as well as incorporation of delays are avoided. The number of resource elements is decided such that the data transmitted to the network coding node is provided to end-nodes (302, 306, 502, 506, 602, 606) by sending one and the same representation of the data from a first and a second end-node, to said first and second end-nodes enabling extracting data originated from the differing end-node.