Hybrid Spectrum Access Probe Framework for CBRS
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Solution Overview
Problem
Existing network access techniques, such as CDMA and LTE, conflict with Citizens Broadband Radio Service (CBRS) spectrum access due to differing power management and access procedures, leading to inefficiencies in network access and spectrum utilization.
Innovation Solution
A hybrid framework that combines spectrum access system (SAS) and access probe methods, allowing user equipment (UE) to perform level ramping of access probe signals and register with the SAS for higher power access, enabling seamless access to CBRS spectrum while adhering to CBRS power restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional CDMA or LTE access procedures are used in CBRS spectrum, then network access can be established, but power management conflicts arise due to differing power restrictions and access protocols
Solution Approach 1:
The system dynamically adapts the access procedure based on device type and spectrum conditions. Category A CBSDs use traditional random access procedures, while Category B CBSDs use the hybrid SAS-probe framework. The UE determines which procedure to use based on its capabilities and the granted spectrum type, making the system flexible and adaptable to different operational scenarios.
Solution Approach 2:
The invention changes the access protocol parameters based on the operational mode. In random access mode, traditional LTE/CDMA parameters are used. In SAS-granted spectrum mode, the system transitions to a probe-based approach with power levels and procedures dictated by SAS authorization, effectively changing the operational parameters to match CBRS requirements.
2Reliability
If access probe power is increased to improve signal strength, then access reliability improves, but it may exceed CBRS power restrictions for certain device types
Solution Approach 1:
The SAS acts as an intermediary that authorizes the UE to transmit probes at higher power levels than normally permitted. Instead of the UE directly deciding to increase power (which would violate CBRS limits), the SAS provides explicit authorization, making the high-power transmission compliant with spectrum rules. This mediator approach resolves the conflict between needing high power for reliability and maintaining power restrictions.
Solution Approach 2:
The system performs preliminary power level determination through SAS authorization before the actual probe transmission. The UE first receives authorization from the SAS specifying the permitted power level, then transmits probes at that authorized level. This preliminary action ensures that high-power transmissions only occur when compliant with CBRS regulations, resolving the power vs. reliability contradiction.
3Speed
If traditional random access procedures are used, then access speed is maintained, but spectrum utilization efficiency decreases due to lack of coordination with SAS
Solution Approach 1:
The hybrid framework incorporates feedback from the SAS to the UE regarding spectrum availability and authorized access parameters. The SAS monitors spectrum conditions and provides real-time authorization feedback, allowing the UE to adjust its probe transmissions accordingly. This feedback loop enables efficient spectrum utilization while maintaining rapid access through the probe-based approach.
Solution Approach 2:
The invention merges the traditional random access procedure with the SAS authorization framework. The fast probe-based access method is combined with SAS coordination, creating a hybrid approach that achieves both rapid access (like traditional methods) and efficient spectrum utilization (through SAS coordination). This merging resolves the contradiction between speed and efficiency.
4Reliability
If level ramping of access probes is implemented to adapt to signal strength, then access reliability improves, but access procedure complexity increases
Solution Approach 1:
The UE autonomously determines its own power level for probe transmission based on SAS authorization and signal conditions, without requiring complex network coordination for each power adjustment. The device self-manages the level ramping process by comparing its received signal strength with authorized power levels, making the complexity localized to the UE rather than requiring complex system-wide coordination.
Data Source
AI summary
Novel tools and techniques for are provided for implementing a hybrid spectrum access system and access probe framework. A system includes a base station coupled to a network, a spectrum access system, and user equipment coupled to the base station and the spectrum access system. The user equipment is configured to transmit, to the base station, a first network access request following a first access sequence while transmitting signals under a first power limit. If no response is obtained from the base station, the user equipment is configured to transmit a second network access request above the first power limit, but under a second power limit. The user equipment is configured to obtain spectrum access from the spectrum access system and transmit a second network access request to the base station.