Dynamic Time Slot Allocation in DSI Sensor Bus Systems
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Solution Overview
Problem
In motor vehicle sensor arrangements using the DSI protocol, bandwidth for data transmission from slaves to the master can be reduced due to empty or insufficient time slots, leading to delayed information availability for reacting to environmental changes, especially in driver assistance systems.
Innovation Solution
The method dynamically allocates time slots to sensor units based on their data transmission needs, selecting groups of sensor units for each measurement cycle and adjusting the number of time slots according to the expected data volume, ensuring only relevant sensor units are assigned time slots, and repeating cycles as necessary to accommodate all data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed time slots are allocated to sensor units in PDCM mode, then communication structure is simple and stable, but bandwidth utilization decreases when some sensor units have no data to transmit
Solution Approach 1:
The patent implements dynamic time slot allocation where the master device adjusts the number of time slots assigned to each slave device based on actual data transmission needs. This allows the system to adapt between fixed allocation (when all sensors have data) and flexible allocation (when some sensors have no data), resolving the contradiction between bandwidth efficiency and system complexity.
Solution Approach 2:
The system changes the parameter of time slot quantity dynamically. The master device can allocate different numbers of time slots to different slave devices based on their data volume requirements, transforming the fixed parameter into a variable one to optimize bandwidth utilization without excessive complexity.
2Reliability
If multiple cycles are used to transmit all sensor data, then complete data transmission is achieved, but response time increases affecting driver assistance system performance
Solution Approach 1:
The patent enables continuous data transmission by allowing slave devices to transmit data in multiple time slots within a single cycle when needed. This eliminates the need for multiple complete cycles, maintaining data transmission completeness while reducing overall delay and improving response time for driver assistance systems.
Solution Approach 2:
The master device preliminarily determines which slave devices have substantial data to transmit and allocates sufficient time slots in advance within the current cycle. This preliminary action prevents the need for subsequent cycles, ensuring both complete data transmission and timely response.
3Loss of information
If all sensor units are assigned time slots in every cycle, then no data is lost, but bandwidth is wasted when some sensor units have no data to transmit
Solution Approach 1:
The patent extracts only the necessary time slots needed for actual data transmission. The master device identifies which slave devices have data to transmit and allocates time slots only to those devices, removing unnecessary time slot allocations and thus eliminating bandwidth waste while maintaining data completeness.
Solution Approach 2:
The system applies partial action by allocating time slots to only those slave devices that have data to transmit, rather than all slave devices. This partial allocation optimizes bandwidth utilization efficiency while still ensuring complete data transmission from all necessary sources.
Data Source
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AI summary
The invention relates to a method for operating a sensor assembly in a motor vehicle (1) on the basis of a DSI protocol, the sensor assembly (2) having a central unit (3) as a master and a plurality of sensor units (S1, S2, S3, S4, S5, S6) as slaves controlled by the master, each sensor unit having a receiver (6), and the central unit (3) and the sensor units (S1, S2, S3, S4, S5, S6) being connected to a bus line (4). Via the bus line (4), communication between the central unit (3) and the sensor units (S1, S2, S3, S4, S5, S6) is conducted in such a way that those slaves to which time slots (ZS1, ZS2, ZS3, ZS4, ZS5, ZS6) for the transmitting of data are assigned at all are selected by the master. Thus the time slots (ZS1, ZS2, ZS3, ZS4, ZS5, ZS6) are not assigned statically but rather are assigned dynamically. Specifically, for a certain measurement, not all slaves are assigned a time slot for the transmitting of data. Thus, such a method in which communication between a master and slaves can be conducted regularly with high bandwidth is provided.