Reduced TBS Table for MTC UEs in LTE Networks
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Solution Overview
Problem
Current wireless communication systems face challenges in determining an optimal transport block size (TBS) for machine-type communication (MTC) devices, particularly in LTE networks, due to reduced peak data rates and coverage requirements, which complicates TBS determination and spectral efficiency.
Innovation Solution
The implementation of a reduced TBS table with fewer entries and a maximum TBS value, allowing non-monotonically increasing TBS values, specifically designed for MTC UEs, which enables efficient communication by signaling explicit indices to the UE for TBS selection, independent of the number of assigned RBs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a full TBS table with many entries is used for legacy UEs, then the TBS determination covers a wide range of data rates, but the complexity of TBS determination increases and spectral efficiency decreases for MTC devices
Solution Approach 1:
The patent segments the TBS determination process by creating separate TBS tables for different UE types. A first TBS table with fewer entries is designated for MTC UEs, while a second TBS table with more entries serves legacy UEs. This segmentation allows MTC devices to use a simplified table, reducing determination complexity while legacy devices continue to benefit from the comprehensive table for wide data rate coverage.
Solution Approach 2:
The patent applies local quality by tailoring the TBS table characteristics to specific UE types. For MTC UEs, the TBS table is optimized with fewer entries appropriate for their reduced peak data rates, while legacy UEs receive access to a more comprehensive table. This localized optimization ensures each UE type uses a table matched to its specific performance characteristics and requirements.
2Ease of manufacture
If TBS values are constrained to be monotonically increasing in the TBS table, then the table structure is simple and easy to implement, but the flexibility in TBS selection is reduced for optimized spectral efficiency
Solution Approach 1:
The patent introduces dynamics by allowing non-monotonically increasing TBS values in the TBS table for MTC UEs. This enables the TBS selection to be optimized for spectral efficiency rather than following a rigid increasing pattern. The base station can select TBS values that best match the channel conditions and traffic requirements, providing flexibility while the UE follows base station indications.
3Power
If the TBS table is designed for legacy UEs with higher peak data rates, then the maximum TBS is higher, but the spectral efficiency and coverage are suboptimal for MTC devices with reduced peak data rates
Solution Approach 1:
The patent applies parameter changes by creating a TBS table specifically optimized for MTC UE parameters, including reduced peak data rates. The first TBS table contains entries and maximum TBS values tailored to MTC capabilities, rather than using the second TBS table designed for legacy UEs with higher data rates. This parameter optimization improves spectral efficiency and coverage for MTC devices.
Data Source
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AI summary
Aspects of the present disclosure provide techniques that may be applied in systems comprising machine type communication (MTC) user equipments (UEs). An exemplary method performed by a base station comprises using a first transport block size (TBS) table to communicate with a first type of user equipment (UE), wherein the first TBS table reuses some entries from existing TBS tables, using a second TBS table to communicate with a second type of UE, wherein the first type of UE supports a reduced peak data rate relative to the second type of UE, signaling information to the first type of UE for use in determining a TBS from the first TBS table, and communicating with the first type of UE, with one or more transmissions having a payload with a number of bits determined based on a TBS value from the first TBS table selected based, at least in part, on the signaled information.