USB Broadcast Receiver Bandwidth Management for CAM Decryption
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Solution Overview
Problem
Broadcast receiving devices compatible with the DVB-CI Plus standard using a USB CAM face issues with bandwidth variation due to connected devices, leading to improper decryption of encrypted signals.
Innovation Solution
A broadcast receiving device with a USB port for a conditional access module (CAM) that measures communication performance and ensures necessary bandwidth for decryption by determining whether the communication performance meets the required bit rates for both the CAM and connected devices, allowing proper decryption and viewing of pay broadcasts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple devices are connected to USB ports in a broadcast receiving device, then device versatility and functionality are improved, but bandwidth availability for conditional access module (CAM) decryption deteriorates
Solution Approach 1:
The patent measures communication performance in advance before data transfer operations begin. By performing bandwidth measurement preliminarily, the system can predict potential bandwidth conflicts and prevent decryption failures before they occur, ensuring reliable CAM operation while allowing multiple USB devices to be connected.
Solution Approach 2:
The patent dynamically adjusts data transfer operations based on measured communication performance. The system determines whether to execute data transfer to connected devices based on available bandwidth, making real-time decisions to maintain decryption reliability while maximizing device versatility. This dynamic control allows the system to adapt to varying bandwidth conditions caused by different USB device configurations.
2Ease of operation
If data transfer to connected USB devices is performed, then device functionality is improved, but communication performance for CAM decryption deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where communication performance is measured and used to determine subsequent data transfer operations. The system receives measurement results about available bandwidth and uses this feedback to decide whether to proceed with data transfer to USB devices, ensuring that decryption speed requirements are met while still allowing device connectivity.
3Adaptability or versatility
If bandwidth is allocated to multiple USB devices, then device functionality is improved, but decryption performance deteriorates
Solution Approach 1:
By measuring communication performance before data transfer operations, the system preliminarily assesses available bandwidth to ensure decryption accuracy will be maintained. This preliminary assessment prevents bandwidth allocation that would compromise decryption performance while still supporting multiple USB devices.
Solution Approach 2:
The system dynamically determines bandwidth allocation based on measured performance characteristics. Rather than static allocation, the system adjusts data transfer operations in real-time based on available bandwidth, ensuring decryption accuracy is maintained while maximizing USB device support capability.
Data Source
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AI summary
A broadcast receiving device includes: a first USB port to connect CAM that decrypts transport streams and outputs decode results; a measurer that measures communication performance via USB by data-transferring with the CAM; a receiver that receives broadcast signals and outputs transport streams; a controller that data-transfers with the CAM for transmitting the transport stream to the CAM and receiving a decryption result; a second USB port to connect a device; a determining unit that, when an data transfer operation with the device connected to the second USB port is received, determines whether a predetermined condition that transfer with a first bit rate necessary for data-transfer with the CAM is achieved and transfer with a second bit rate necessary for data transfer with the device is achieved is satisfied based on the communication performance. When the predetermined condition is determined to be satisfied, the controller data-transfers with the device.