WLAN Rx Chain Suspend via PLCP Header Analysis
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Solution Overview
Problem
Conventional WLAN devices consume power continuously, even when receiving undesignated packets, which are frequently encountered in congested environments, leading to inefficient power usage and reduced battery life in portable devices.
Innovation Solution
Implementing a preamble decode-based receive suspend algorithm that analyzes the PLCP header length field to determine when to turn off the Rx chain, specifically the analog and digital portions, for undesignated packets, ensuring efficient power conservation without missing incoming packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Rx chain remains continuously active to receive all packets, then no packets are missed, but power consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by decoding the PLCP header (which contains length information) before making the decision to suspend or continue reception. This allows the device to prepare for potential suspension in advance, ensuring that if the packet is undesignated, the Rx chain can be turned off promptly without missing any critical information, thus resolving the contradiction between reliability and power consumption.
Solution Approach 2:
The patent segments the packet reception process into two distinct phases: first decoding the PLCP header to determine packet characteristics, then based on that information, either continuing to receive the full packet or suspending reception. This segmentation allows the device to avoid processing entire undesignated packets, significantly reducing power consumption while maintaining reliability for designated packets.
2Use of energy by moving object
If the Rx chain is suspended during undesignated packets to save power, then power consumption decreases, but there is risk of missing designated packets
Solution Approach 1:
The patent uses preliminary action by examining the PLCP header (which is decoded at the lowest basic rate and contains length field information) before suspending the Rx chain. This preliminary examination ensures that the device has sufficient information to make an informed decision, reducing the risk of incorrectly suspending during a designated packet.
Solution Approach 2:
The patent implements feedback by using the length field information from the PLCP header to determine whether to suspend reception. This feedback mechanism allows the device to adjust its reception behavior based on the actual packet characteristics, ensuring that designated packets are not missed while still achieving power savings for undesignated packets.
3Productivity
If the device decodes packets at higher rates to improve reception speed, then productivity increases, but power consumption increases and compatibility with legacy devices decreases
Solution Approach 1:
The patent segments the decoding process by first decoding the PLCP header at the lowest basic rate (which all devices support), then based on the length field information, deciding whether to continue receiving at the original rate or suspend. This segmentation allows legacy devices to operate efficiently without attempting to decode higher-rate packets, reducing their power consumption while maintaining compatibility.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the reception rate based on packet designation. For designated packets, the device can maintain higher reception rates for improved productivity. For undesignated packets, the device switches to a lower power state by suspending reception, thus optimizing the balance between productivity and power consumption based on actual network conditions.
Data Source
AI summary
A WLAN device includes a processor implementing a MAC layer and a PHY layer which is coupled to a transceiver including a receive (Rx) chain and a transmit (Tx) chain that is coupled to an antenna. A preamble decode-based receive suspend algorithm has software stored in a memory that is implemented by the processor or by hardware including digital logic. The algorithm responsive to receiving a packet including a Physical Layer Convergence Protocol (PLCP) header, a MAC header, and data, is for analyzing a length field in the PLCP header to determine whether the packet is an undesignated packet and whether there is sufficient time remaining for implementing a turning off and then back on of an analog portion of the Rx chain to avoid missing a next packet. If the undesignated packet and sufficient time are present, the analog portion of the Rx chain is turned off.