Asymmetric Retry Limits for Full Duplex Control Channel

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Solution Overview

Problem

Existing multimedia communication systems with half-duplex translation layers face challenges in transitioning to full-duplex link layers without complex conflict resolution logic, which affects bandwidth efficiency and compatibility with existing systems.

Innovation Solution

Implementing a full-duplex control channel using time domain multiplexed (TDM) frames with offset time slots and asymmetric maximum retry limits to reduce conflict handling complexity and prevent deadlocks, allowing for simultaneous data transmission in both directions while maintaining half-duplex translation layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full duplex link layer is implemented to increase bandwidth, then bandwidth efficiency is improved, but device complexity increases due to complex conflict resolution logic

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidconflict resolution logic

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the TDM frame into distinct time slots allocated to different virtual channels, with odd-numbered slots for source-to-sink traffic and even-numbered slots for sink-to-source traffic. This segmentation eliminates conflicts by ensuring that only one direction can transmit at a given time slot, removing the need for complex conflict resolution logic while maintaining full-duplex bandwidth efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different TDM frame timing characteristics to different virtual channels based on their traffic direction requirements. Each virtual channel is configured with specific time slot allocations that match its transmission direction, allowing optimized local performance for each channel while maintaining overall system efficiency.

Inventive Principle:

Principle #3Local quality

2Productivity

If full duplex link layer is implemented to increase bandwidth, then bandwidth efficiency is improved, but backwards compatibility with existing half duplex translation layers deteriorates

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidbackwards compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a translation layer as an intermediary between the full-duplex link layer and half-duplex translation layers. This translation layer handles the complexity of TDM frame management and conflict resolution, allowing existing half-duplex translation layers to interface with the full-duplex link layer without modification, thus maintaining backwards compatibility while achieving improved bandwidth efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If symmetric maximum retry limits are used for source and sink devices, then fairness is improved, but communication deadlocks may occur

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidretry control logic

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements asymmetric maximum retry limits where the source device and sink device are assigned different retry thresholds. This asymmetry prevents deadlock scenarios by ensuring that at least one device will back off and wait for the other to complete its transmission, thereby improving communication reliability without requiring complex symmetric retry control logic.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS9537646B2Retry disparity for control channel of a multimedia communication link

Publication Date: 2017.01.03 LATTICE SEMICON CORP

AI summary

A multimedia system for data communications. A source device communicates data over a full duplex control channel of a multimedia communication link. The source device has a first link layer that retries unsuccessful data communications over the full duplex control channel until a first maximum retry limit of the first link layer is reached. A sink device communicates data over the full duplex control channel of the multimedia communication link. The sink device has a second link layer that retries unsuccessful data communications over the full duplex control channel until a second maximum retry limit of the second link layer is reached, where the second maximum retry limit is different than the first maximum retry limit.