Network Node Unlicensed Spectrum Code Block Group Transmission
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Solution Overview
Problem
In unlicensed spectrum operations, the limited time between channel sensing and transmission initiation leads to inefficient radio resource usage and delays due to the need for retransmitting entire transport blocks when channels are sensed as busy, as existing methods wait for acknowledgement before retransmitting.
Innovation Solution
A network node that assesses clear channels and transmits code block groups without waiting for acknowledgement, using the same redundancy version for retransmissions and aligning code block groups to adjacent channels, thereby optimizing resource usage and reducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network node waits for acknowledgement before retransmitting code block groups, then the reliability of transmission is improved, but the transmission time and radio resource utilization deteriorate
Solution Approach 1:
The network node performs preliminary actions by preparing code block groups for retransmission in advance and initiating the retransmission process before receiving the acknowledgement signal from the receiver. This allows the system to overcome the delay caused by waiting for feedback, while still maintaining transmission reliability through the HARQ mechanism.
2Reliability
If the network node retransmits entire transport blocks when channels are sensed as busy, then the reliability is maintained, but the radio resource utilization and productivity deteriorate
Solution Approach 1:
The network node segments the transport block into smaller code block groups, allowing selective retransmission of only the affected code block groups rather than the entire transport block. This segmentation enables more efficient radio resource utilization by transmitting only the necessary portions that require retransmission.
Solution Approach 2:
The network node applies local quality by treating different code block groups differently based on their transmission status. Instead of uniform retransmission of all blocks, the system identifies and retransmits only the specific code block groups that were not successfully transmitted on busy channels, optimizing resource allocation.
3Productivity
If the network node aligns code block groups to adjacent channels, then the radio resource utilization is improved, but the complexity of channel assessment and mapping increases
Solution Approach 1:
The network node performs preliminary mapping and alignment of code block groups to adjacent channels during the preparation phase. By pre-establishing the mapping relationship between code block groups and available channels, the system simplifies the actual transmission process and reduces real-time complexity.
Data Source
AI summary
A network node is arranged to provide communication at least in an unlicensed band where clear channel assessment, CCA, is required before transmissions. The unlicensed band comprises a plurality of carriers, or sets of carriers, defining channels. The network node is arranged to prepare code block groups comprising code blocks from transport blocks, which transport blocks each comprises a payload intended for a respective receiver, wherein each code block comprises a checksum enabling a hybrid automatic repeat request, HARQ, procedure on a per code block group basis, map the code block groups to a wideband signal comprising a consecutive set of channels on the carriers of the unlicensed band, assess whether the channels, respectively, are clear, and transmit the code block groups mapped on the channels which are clear and omit transmissions of code block groups mapped on channels that are not clear, wherein the assessment and the transmissions are performed within a first time interval, and transmit code blocks groups omitted to be transmitted using the HARQ procedure for retransmission prior receiving a non-acknowledgement, NAK, from a respective receiver of the code block group.