White Space Device Channel Allocation via Dynamic Interference Constraints
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Solution Overview
Problem
Current methods for allocating transmit power to white space devices (WSDs) in cognitive radio systems result in suboptimal utilization due to worst-case assumptions, leading to excessive interference protection and inefficient resource allocation, as the geo-location database lacks information on actual WSD locations and usage patterns.
Innovation Solution
A network node is introduced to control and optimize the allocation of white space channels and transmit power to WSDs by deriving constraints based on the position of each WSD and interference thresholds, ensuring that only actively transmitting WSDs are considered, thereby eliminating the need for worst-case assumptions and allowing for adaptive resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the geo-location database uses worst-case assumptions for interference calculation, then primary service protection is ensured, but secondary spectrum utilization becomes suboptimal
Solution Approach 1:
The system implements feedback by having WSDs report their actual positions and transmission status to the master WSD. The master WSD continuously updates the interference calculation based on this feedback, replacing static worst-case assumptions with dynamic actual state information. This allows the system to maintain primary service protection while accurately reflecting real interference conditions, thereby improving secondary spectrum utilization.
Solution Approach 2:
The patent transforms the static interference protection mechanism into a dynamic one. Instead of using fixed worst-case interference margins, the system dynamically calculates interference based on actual WSD positions, active transmissions, and real-time channel conditions. This dynamic approach allows the secondary system to adaptively utilize spectrum resources while maintaining adequate primary service protection.
2Object-affected harmful factors
If the geo-location database allocates transmit power based on worst-case scenarios, then interference to primary services is minimized, but resource allocation efficiency decreases
Solution Approach 1:
The master WSD performs preliminary actions by collecting position information and transmission status from all slave WSDs before calculating interference and allocating resources. This preliminary gathering of actual state information enables the system to make informed resource allocation decisions rather than relying on conservative worst-case assumptions, thereby improving resource allocation efficiency while maintaining adequate interference protection.
Solution Approach 2:
The system changes the parameters used for interference calculation from static worst-case values to dynamic actual parameters including real WSD positions, active transmission states, and current channel conditions. This parameter transformation allows for more accurate interference assessment and more efficient resource allocation, as the system adapts to actual operating conditions rather than preparing for hypothetical maximum interference scenarios.
3Reliability
If the system assumes all WSDs are actively transmitting, then interference protection is conservative and reliable, but spectrum opportunities are underutilized
Solution Approach 1:
The system uses feedback mechanisms where slave WSDs report their actual transmission status and position to the master WSD. This feedback enables the master to distinguish between actively transmitting and non-transmitting WSDs, allowing it to calculate interference based on actual active transmitters rather than assuming all WSDs are transmitting. This improves spectrum opportunity utilization while maintaining reliable interference protection for primary services.
Data Source
AI summary
The disclosure relates to a network node of a wireless network, and to a related method of controlling interference generated by at least one white space device controlled by the network node. The method comprises transmitting a request for information regarding channels available for secondary usage to the remote entity, and receiving information from the remote entity, the information indicating a channel available for secondary usage, a critical position associated with said channel, and an interference threshold for the critical position. The method also comprises deriving a constraint for the allocation of said channel to the at least one white space device, based on a position of the at least one white space device, the critical position, and the interference threshold, and allocating said channel and a transmit power to the at least one white space device based on the derived constraint, whereby the interference generated in the critical position by the at least one white space device is kept below the interference threshold.