Reduced CRC MPDCCH Control Messages for MTC Coverage
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Solution Overview
Problem
Current techniques for coverage extension in LTE networks, such as signal repetition, are inefficient and resource-intensive, especially for Low Complexity Machine Type Communication (LC-MTC) devices, leading to increased latency and false alarm probabilities due to large CRC sizes and complex channel allocation processes.
Innovation Solution
The implementation of a reduced CRC size for the Machine Physical Downlink Control Channel (MPDCCH) scrambled with a time-dependent code, specifically an 8-bit CRC scrambled with a hash value based on the UE's RNTI, subframe, and system frame numbers, to improve coverage and reduce resource usage while minimizing false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If signal repetition is used for coverage extension, then coverage is improved, but latency increases and resource consumption increases
Solution Approach 1:
The patent extracts and removes the CRC field from the DCI message format used in MPDCCH transmissions. By taking out this redundant error checking component (which is unnecessary when repetitions are used), the message payload is reduced, allowing more efficient use of repeated transmissions and reducing the total time required for coverage extension.
Solution Approach 2:
The patent applies partial action by selectively removing only the CRC field while retaining other essential DCI components. This partial modification achieves the goal of reducing latency and resource consumption without compromising the essential functionality of the control message.
2Area of stationary object
If signal repetition is used for coverage extension, then coverage is improved, but resource consumption increases
Solution Approach 1:
The patent extracts and removes the CRC field from the DCI message format used in MPDCCH transmissions. By taking out this redundant error checking component (which is unnecessary when repetitions are used), the message payload is reduced, allowing more efficient use of repeated transmissions and reducing the total time required for coverage extension.
Solution Approach 2:
The patent applies partial action by selectively removing only the CRC field while retaining other essential DCI components. This partial modification achieves the goal of reducing latency and resource consumption without compromising the essential functionality of the control message.
3Reliability
If large CRC size is used in DCI message, then error detection capability is improved, but false alarm probability increases
Solution Approach 1:
The patent extracts and removes the CRC field from the DCI message format used in MPDCCH transmissions. By taking out this redundant error checking component (which is unnecessary when repetitions are used), the message payload is reduced, allowing more efficient use of repeated transmissions and reducing the total time required for coverage extension.
Data Source
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AI summary
A terminal device for use in a wireless telecommunications system, the terminal device comprising; receiver circuitry; transmitter circuitry; and controller circuitry; wherein the receiver circuitry is operable to receive a first control message from a base station, the first control message indicating a radio resource for use by at least one of the receiver circuitry and transmitter circuitry to exchange a signal with the base station and the first control message comprising a code generated on the basis of an identifier of an intended terminal device and a value of a time-dependent parameter at a transmission time of the first control message, the intended terminal device being a terminal device intended for exchanging the signal with the base station; and the controller circuitry is operable to: attempt to perform a predetermined process using the code of the first control message, an identifier of the terminal device and the value of the time-dependant parameter at the transmission time of the first control message; wherein: if the predetermined process is not successfully completed, disregard the first control message; if the predetermined process is successfully completed, control at least one of the receiver circuitry and transmitter circuitry to exchange a signal with the base station using the radio resource indicated by the first control message.