Sidelink Interlaced Waveform Unlicensed Band PSD Compliance
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Solution Overview
Problem
Current sidelink (SL) communication designs for unlicensed bands face challenges in meeting power spectral density (PSD) and occupied channel bandwidth (OCB) constraints, requiring a substantial fraction of the channel to be occupied, which is difficult to achieve with localized frequency transmissions.
Innovation Solution
An interlaced design is introduced to map physical channels to resource blocks, allowing for a higher total transmit power while adhering to PSD limits, by spreading resources across multiple interlaces within a sub-band, maintaining compatibility with existing SL procedures with minimal modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If localized frequency transmissions are used for SL communication in unlicensed bands, then device complexity is reduced and implementation is simplified, but the occupied channel bandwidth constraint cannot be met as a substantial fraction of the channel cannot be occupied
Solution Approach 1:
The patent divides the frequency resources into multiple interlaces (first interlace and second interlace) that are distributed across the available bandwidth. Instead of using a single localized frequency transmission, the communication signals are segmented across these multiple interlaces, allowing the system to occupy a substantial fraction of the channel bandwidth while maintaining implementation simplicity through standardized procedures.
2Reliability
If frequency interlaced design is used to occupy substantial fraction of channel, then PSD and OCB constraints are met, but device complexity increases due to modified resource mapping
Solution Approach 1:
The patent designs the frequency interlaced resource mapping to be compatible with existing SL communication procedures. The same resource pool configuration and signal processing techniques can be used across different scenarios (unicast, groupcast, broadcast), reducing the need for separate complex handling of each case while maintaining regulatory compliance through the interlaced structure.
3Device complexity
If localized frequency transmissions are used, then device complexity is lower, but total transmit power is limited due to PSD constraints
Solution Approach 1:
The patent transitions from localized frequency transmissions to frequency interlaced transmissions, effectively changing the frequency domain distribution dimension. By spreading resources across multiple interlaces in the frequency domain, the system can increase total transmit power while maintaining compliance with PSD constraints through the distributed frequency occupation pattern.
Data Source
AI summary
An apparatus and a method are disclosed for SL communication over an unlicensed band by utilizing a frequency interlaced design. A method performed by a UT includes determining whether the UE is operating in a localized mode or an interlaced mode for SL communication, and in response to determining that the LE is operating in the interlaced mode, decoding first stage SCI of a PSCCH based on an interlaced mapping scheme, decoding second stage SCI of a PSSCH based on the decoded first stage SCI, and decoding the PSSCH based on the decoded first and second stage SCI.