Node-Specific Reservation Signals for Spectrum Sharing
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Solution Overview
Problem
Current priority-based coordinated access schemes in wireless communication systems face challenges in differentiating node-specific reservation responses (RRS) signals, leading to unnecessary resource underutilization and increased monitoring complexity due to the summation of signals from multiple nodes.
Innovation Solution
Employing node-specific RRS signals with orthogonal waveforms, such as cyclically-shifted root sequences, allows multiple nodes to transmit unique reservation information on the same resource, enabling monitoring nodes to differentiate and improve spectrum sharing efficiency by reducing unnecessary yielding and enhancing resource reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all target receivers transmit RRS signals on the same resource, then resource overhead is reduced and monitoring complexity is reduced, but node-specific reservation information cannot be differentiated and unnecessary yielding occurs
Solution Approach 1:
The patent segments the RRS signal transmission by assigning different orthogonal waveforms (e.g., different cyclic shifts of root sequences) to different target receivers. This allows the monitoring node to differentiate between RRS signals from different nodes while still using the same time-frequency resource, thus resolving the contradiction between reducing resource overhead and preserving node-specific information.
Solution Approach 2:
The patent changes the waveform parameter (cyclic shift value) of the RRS signals to encode node-specific information. By varying this parameter, multiple target receivers can transmit simultaneously on the same resource without collision, and the monitoring node can identify each signal's origin, thereby maintaining information differentiation while reducing monitoring complexity.
2Productivity
If multiple target receivers transmit RRS signals on the same resource, then resource utilization is improved, but signal differentiation becomes impossible and unnecessary spectrum yielding occurs
Solution Approach 1:
The patent divides the RRS signal space by introducing orthogonal waveforms with different cyclic shifts. This segmentation allows multiple target receivers to occupy the same time-frequency resource while maintaining signal distinguishability, thus improving spectrum utilization without sacrificing the reliability of spectrum access decisions.
Solution Approach 2:
The orthogonal waveform acts as an intermediary that carries node-specific identification information. The monitoring node uses this intermediary to reliably identify the source of each RRS signal, ensuring accurate spectrum access decisions while allowing multiple receivers to share the same transmission resource.
3Productivity
If node-specific RRS signals with orthogonal waveforms are used, then node-specific reservation information can be differentiated and spectrum sharing efficiency is improved, but signal complexity increases
Solution Approach 1:
The patent uses parameter changes (cyclic shifts of root sequences) to generate node-specific waveforms. This approach improves spectrum sharing efficiency by enabling signal differentiation while keeping the signal structure relatively simple and based on established mathematical sequences, thus limiting the increase in processing complexity.
Solution Approach 2:
The patent employs universal mathematical sequences (root sequences) that serve multiple functions: they provide orthogonal waveforms for signal differentiation, maintain good autocorrelation and cross-correlation properties for reliable detection, and can be generated efficiently with simple algorithms. This multi-functionality improves spectrum sharing efficiency while minimizing the increase in device complexity.
Data Source
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AI summary
Wireless communications systems and methods related to sharing a spectrum using node-specific medium reservation signals are provided. A first wireless communication device a first configuration designated to the first wireless communication device. The first configuration indicates at least one waveform for representing reservation information. The first wireless communication device transmits a reservation signal to reserve a transmission opportunity (TXOP) in a shared spectrum. The reservation signal includes a first waveform representing corresponding first reservation information based on the first configuration. The first waveform is associated with a root sequence and a cyclic-shift value. The first reservation information indicates a transmit power level of the reservation signal. The first reservation information indicates an interference tolerance level of the first wireless communication device. The first reservation information indicates a reserved duration within the TXOP.