Transport Block Size Scaling for Extended Subframes
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Solution Overview
Problem
The existing methods for determining transport block size (TBS) in LTE-based 5G terrestrial broadcasting are limited, resulting in a relatively small data transmission rate due to the increased symbol length exceeding 1 ms, which restricts the signal transmission rate in multimedia broadcast multicast service single frequency networks (MBSFN).
Innovation Solution
A method and apparatus for determining TBS by using a communication device that considers the modulation and coding scheme (MCS) and frequency domain resource occupied by the broadcast channel, employing tables that map multiple layers to determine a larger TBS, scaling intermediate variables, and calculating based on the quantity of resource elements (REs) to enhance data transmission capacity in subframes exceeding 1 ms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the cyclic prefix length is increased to exceed 300 μs for larger coverage area, then the coverage area is improved, but the symbol length exceeds 2.7 ms causing the TBS to be relatively small and limiting the signal transmission rate
Solution Approach 1:
The patent changes the parameters used for TBS determination by introducing a scale factor (k) that multiplies the intermediate TBS variable. This allows the TBS to be scaled proportionally with the extended subframe duration, converting the harmful effect of extended symbol length into a beneficial scaling opportunity that increases data transmission capacity while maintaining the extended CP for large coverage area
Solution Approach 2:
The patent introduces a new dimension of time scaling by using the subframe duration ratio (k = T_actual / T_reference) as a multiplicative factor. This transforms the problem from a two-dimensional constraint (TBS vs. resource blocks) to a three-dimensional solution space that incorporates time duration scaling, enabling TBS to increase proportionally with extended subframe length
2Productivity
If the symbol length is extended to exceed 1 ms for new numerology, then the frequency domain resource efficiency is improved, but the conventional TBS configuration method results in relatively small TBS and limits data transmission amount
Solution Approach 1:
The patent modifies the TBS determination parameters by introducing a scale factor that accounts for the extended symbol duration. This parameter change allows the TBS to be calculated based on the actual subframe duration rather than the conventional 1 ms reference, thereby increasing both the data transmission amount and maintaining frequency domain resource efficiency
3Ease of operation
If the conventional TBS determination method is used for extended subframes, then the method simplicity is maintained, but the TBS is relatively small and the signal transmission rate is limited
Solution Approach 1:
The patent performs preliminary calculation of the scale factor k based on the actual subframe duration before determining the TBS. This preliminary action allows the subsequent TBS calculation to proceed using a simple multiplicative scaling of the intermediate variable, maintaining method simplicity while achieving increased signal transmission rate through the pre-computed time duration ratio
Data Source
AI summary
The present disclosure relates to transport block size (TBS) determining methods and apparatus. One example TBS determining method includes determining a second intermediate variable based on a determined TBS index, a frequency domain resource occupied by a first broadcast channel, and a second table, and determining a TBS based on the second intermediate variable and a scale factor, where the scale factor is greater than 1.