PHY Reception Mode Control for CCK/OFDM Power Savings

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Solution Overview

Problem

Wireless Local Area Network (WLAN) devices that support both Complimentary Code Keying (CCK) and Orthogonal Frequency Division Multiplexing (OFDM) modulation schemes consume unnecessary power and degrade performance due to repeated modulation type detection in autodetection mode.

Innovation Solution

Implementing a PHY controller that allows selection of three reception modes: exclusive OFDM, exclusive CCK, or auto-detection, with direct activation of receivers to bypass autodetection module and conserve power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If autodetection mode is used to determine modulation type, then the device can receive both CCK and OFDM frames, but power consumption increases and performance degrades due to repeated detection

Engineering Contradiction:

Improvemodulation type detection capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between autodetection mode and direct reception mode based on the received signal type. When an OFDM preamble is detected, the system transitions from autodetection to direct OFDM reception, avoiding continued power-consuming modulation detection. This dynamic adaptation resolves the contradiction by making the detection capability conditional rather than continuous.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If both CCK and OFDM receiving components are active in autodetection mode, then the device can handle multiple modulation schemes, but device complexity increases

Engineering Contradiction:

Improvemulti-modulation supportVSAvoidreceiver component complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes the autodetection functionality once the modulation type is identified. After detecting the preamble and determining the modulation scheme, the system eliminates the need for continued autodetection operations by switching to a dedicated reception mode. This extraction principle reduces device complexity while preserving multi-modulation support capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If repeated modulation detection is performed for each incoming frame, then the device can adapt to varying modulation types, but throughput decreases

Engineering Contradiction:

Improvemodulation adaptationVSAvoiddata throughput

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The system performs preliminary detection of the preamble to identify the modulation type before full frame reception. This preliminary action allows the system to configure the receiver appropriately in advance, avoiding repeated detection during the data payload reception. By separating the detection phase from the reception phase, the system maintains adaptability while improving throughput.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7486737B2Apparatus and method of controlling a physical layer of a communication device

Publication Date: 2009.02.03 INTEL CORP

AI summary

Embodiments of the invention describe a method and device for controlling a physical layer of a communication device to operate in one of three modes of communication. In a first mode, the device is able to demodulate frames of a Complimentary Code Keying (CCK) modulation type. In a second mode, the device is able to demodulate frames of an Orthogonal Frequency Division Multiplexing (OFDM) modulation type. In a third, autodetection mode, the device is able to automatically detect the modulation type of a received frame and to configure the communication device to demodulate the received frame according to the detected modulation type. Control of the physical layer may be based on criteria related to prior transmissions received or transmitted by the communication device.