Conditional Access Device Standby Power Reduction
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Solution Overview
Problem
Consumer electronics face challenges in meeting EnergyStar certification requirements for low-power standby mode, particularly with the conditional access device consuming more than allocated power in digital cable television systems.
Innovation Solution
Implementing a determinate message window for entitlement management messages (EMMs) to reduce the power consumption of the QPSK receiver by only powering it up during expected message windows, using a timer to manage the wake signal and ensure the receiver is active only when necessary, and incorporating a secure microprocessor to process EMMs and maintain secure conditional access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the QPSK receiver is kept powered and ready to receive EMM messages at any time, then the conditional access device can reliably receive entitlement management messages, but the power consumption exceeds the EnergyStar requirement of 2.5 Watts for the conditional access device in standby mode
Solution Approach 1:
The system implements periodic action by establishing determinate message windows during which the QPSK receiver is activated to receive EMM messages. The receiver is powered on only during these scheduled intervals and powered off during non-message periods, transforming continuous operation into periodic operation. This resolves the contradiction by maintaining message reception capability while dramatically reducing average power consumption to meet EnergyStar requirements.
Solution Approach 2:
The system applies preliminary action by pre-scheduling and notifying the conditional access device of upcoming message windows in advance. The headend control system sends notifications about when EMM messages will be transmitted, allowing the receiver to be activated only during these predetermined intervals rather than remaining continuously powered, thus reducing standby power consumption while ensuring reliable message reception.
2Use of energy by stationary object
If the QPSK receiver is powered down during standby mode to reduce power consumption, then energy requirements are met, but the device cannot receive EMM messages that may arrive at any time
Solution Approach 1:
The system resolves this contradiction by implementing periodic action through scheduled message windows. Instead of keeping the receiver continuously powered or completely off, the system activates the receiver only during predetermined intervals when EMM messages are expected. This periodic operation maintains the ability to receive messages while achieving the required low power consumption during standby mode.
Solution Approach 2:
The system uses preliminary action by providing advance notification of message window timings to the conditional access device. The headend control system informs the device when messages will be sent, allowing the receiver to be powered up in advance of actual message transmission. This ensures no messages are missed while minimizing the time the receiver remains powered, thus reducing overall power consumption.
Data Source
AI summary
A conditional access device is provided. The conditional access device typically includes conditional access decryption, interface, timing and control logic. The conditional access decryption logic decrypts an incoming signal for use in a consumer electronics device in accordance with previously received entitlement management messages. The interface logic receives a control signal including an entitlement management message window from a headend control system through a receiver in the consumer electronics device. The timing logic asserts an awake signal responsive to the entitlement management message window becoming active. The control logic sends a request to the consumer electronic device to activate a receiver coupled to the headend control system in expectation of receiving an entitlement management message via the control signal in response to assertion of the awake signal. The control logic also communicates the entitlement management message to the conditional access decryption logic. Other systems and method are also provided.