Unlicensed Carrier Scheduling with Physical Indication Signals
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Solution Overview
Problem
The unpredictability of unlicensed spectrum availability in License Assisted Access (LAA) systems leads to resource shortages and waste, as base stations cannot determine with certainty whether allocated unlicensed carriers are available for transmission, resulting in potential unavailability or inefficient resource utilization.
Innovation Solution
A resource allocation method that involves sending scheduling instructions associated with multiple unlicensed carriers, determining available carriers through clear channel assessment, and using physical indication signals to occupy these carriers, ensuring that user equipment can perform transmission on at least one available carrier, thereby reducing resource unavailability and waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a base station schedules user equipment on a single unlicensed carrier, then the scheduling process is simple, but the probability of carrier unavailability increases and transmission reliability deteriorates
Solution Approach 1:
The patent segments the unlicensed spectrum into multiple carriers (at least two carriers) for scheduling user equipment. Instead of relying on a single carrier that may be unavailable, the base station schedules UE on multiple carriers simultaneously, dividing the transmission task across several frequency resources. This segmentation ensures that if one carrier is unavailable, other carriers can still carry the transmission, thereby improving reliability without significantly increasing scheduling complexity.
Solution Approach 2:
The patent changes the parameter of carrier quantity from one to multiple (at least two). By increasing the number of carriers allocated to user equipment, the system transforms the availability probability parameter - the more carriers available, the higher the probability that at least one will be available for transmission. This parameter change directly addresses the reliability issue while maintaining manageable scheduling complexity through efficient resource allocation.
2Reliability
If a base station allocates multiple unlicensed carriers to user equipment, then the probability of available carrier resources increases, but the scheduling instruction complexity increases
Solution Approach 1:
The scheduling instruction is segmented to include information for multiple carriers in a structured manner. Each carrier's allocation information (resource blocks, modulation scheme, etc.) is organized as a separate segment within the overall scheduling instruction. This segmentation allows the UE to efficiently parse and process carrier-specific parameters without being overwhelmed by the complexity of handling multiple carriers as a single block, thus managing instruction complexity while maintaining high availability probability.
Solution Approach 2:
The base station performs preliminary assessment of carrier availability before issuing the scheduling instruction. By pre-evaluating which carriers are available (through CCA or other monitoring mechanisms) and incorporating this information into the scheduling decision, the system prepares the optimal carrier combination in advance. This preliminary action reduces the complexity of real-time scheduling by pre-resolving carrier availability uncertainties, allowing the scheduling instruction to focus only on resource allocation details rather than carrier selection.
3Measurement precision
If a base station performs clear channel assessment before transmission, then the accuracy of carrier availability determination improves, but the time delay increases
Solution Approach 1:
The base station performs clear channel assessment (CCA) in advance of the actual data transmission, during the scheduling phase. By conducting CCA beforehand and using the results to make scheduling decisions, the system determines carrier availability with high accuracy before committing resources. This preliminary CCA action eliminates the need for repeated channel sensing at transmission time, as the scheduling instruction already reflects current channel conditions, thereby reducing transmission delay while maintaining determination accuracy.
Solution Approach 2:
The clear channel assessment is performed periodically at scheduled intervals (e.g., at each scheduling opportunity) rather than continuously or ad-hoc. This periodic CCA approach balances measurement precision with time efficiency - the channel is sampled frequently enough to maintain accurate availability determination, but not so frequently as to create excessive delay. The periodic rhythm of CCA allows the system to stay updated on carrier availability while maintaining a predictable and efficient transmission timeline.
Data Source
AI summary
Embodiments of the present invention disclose a resource allocation method, a transmission method, and apparatuses. The resource allocation method comprises: sending a scheduling instruction, wherein the scheduling instruction comprises: information that is associated with at least two carriers in an unlicensed spectrum allocated to transmission of a user equipment; determining at least one available carrier in the at least two carriers; and sending a physical indication signal on the at least one available carrier, wherein the physical indication signal is used to occupy the at least one available carrier. According to the method and apparatus of the embodiments of the present invention, at least two carriers is allocated to transmission of a user equipment at a scheduling moment, at least one available carrier in the at least two carriers is determined, and a physical indication signal is used to occupy the at least one available carrier, thereby reducing the possibility of occurrence of the problem of resource unavailability and/or resource waste caused by the unpredictability of whether an unlicensed spectrum is available.