Resource Mapping in Unlicensed Spectrum Subbands
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Solution Overview
Problem
In 5G NR-U, resource mapping in unlicensed spectrum is challenging due to varying subband availability, leading to inefficient channel utilization and potential TB decoding failures, especially when not all subbands are available for transmission.
Innovation Solution
The method involves determining a type of resource mapping, either subband-based or wideband-based, where modulated complex symbols are mapped to resource blocks within allocated subbands, with successful subbands used for data transmission, and decoding data based on the determined mapping type, allowing for efficient data transmission even when not all subbands are available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wideband carrier is used for transmission on unlicensed spectrum, then bandwidth efficiency is improved, but channel access reliability deteriorates due to LBT failures on portions of the carrier
Solution Approach 1:
The wideband carrier is divided into multiple subbands (e.g., 4 subbands of 20 MHz each for a 80 MHz carrier). LBT is performed independently on each subband, and data transmission is conducted only on subbands where LBT succeeds. This segmentation allows the system to maintain wideband operation while ensuring reliable channel access on a per-subband basis, resolving the contradiction between bandwidth efficiency and channel access reliability.
2Reliability
If LBT is performed on all subbands before transmission, then fair coexistence with other wireless systems is improved, but channel utilization efficiency deteriorates when some subbands are unavailable
Solution Approach 1:
The system dynamically adapts the resource mapping strategy based on LBT results. When LBT succeeds on all subbands, wideband-based resource mapping is used for optimal throughput. When LBT fails on some subbands, subband-based resource mapping is applied to transmit data only on available subbands. This dynamic adaptation maintains fair coexistence through LBT while maximizing channel utilization efficiency under varying channel conditions.
3Reliability
If subband-based resource mapping is used, then transmission reliability on available subbands is improved, but system complexity increases due to multiple mapping types
Solution Approach 1:
The patent introduces a resource mapping type parameter that can be dynamically switched between wideband-based and subband-based mapping. This parameter is controlled based on LBT results and configuration, allowing the system to maintain transmission reliability through appropriate mapping selection while managing complexity through parameter-based control rather than implementing multiple independent mapping systems.
Data Source
AI summary
Embodiment of the present disclosure relates to methods and apparatuses for resource mapping in unlicensed spectrum. According to an embodiment of the present disclosure, a method can include: receiving data on a first set of subbands, wherein the data is a part of a transport block (TB), the first set of subbands is a subset of a second set of subbands, the second set of subbands is allocated for the TB, and each subband of the second set of subbands has been performed a channel access procedure; determining a type of resource mapping of the TB, wherein the resource mapping includes mapping modulated complex symbols of the TB to resource blocks of the second set of subbands; and decoding the data based on the determined type of resource mapping. Embodiments of the present disclosure propose a technical solution for resource mapping in unlicensed spectrum, which can improve the channel utilization efficiency of NR.