Dynamic Frequency Allocation in Cognitive Radio Networks
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Solution Overview
Problem
Current cognitive radio networks face challenges in accurately allocating dynamic frequencies for secondary users due to the lack of precise location information of primary users and high calculation complexity, leading to reduced accuracy and difficulty in real-time frequency access opportunities, especially in networks with low-performance terminals without sensing functions.
Innovation Solution
A dynamic frequency allocation device and method that generates an opportunity map using spectrum sensing information, access request messages, and density and transmission powers of primary transmitters to determine the probability of successful communication, enabling the allocation of channels with the highest SINR exceeding a predefined reference value, even in regions without installed sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial interpolation is used to predict reception signal strengths in regions without sensors, then frequency access opportunities can be provided in those regions, but the accuracy is lowered because only primary transmitter locations and powers are considered without accounting for interference distribution
Solution Approach 1:
The patent segments the frequency spectrum into multiple channels and divides the network into primary user networks and secondary user networks. By segmenting the sensing requirements and processing interference from different primary transmitters separately, the system can accurately predict reception signal strengths in regions without sensors while managing complexity through structured organization of sensing data and interference calculations.
2Measurement precision
If multiple frequency sensors are used simultaneously to determine frequency access opportunities, then the accuracy of sensing map composition is improved, but the calculation complexity becomes very high making real-time determination difficult
Solution Approach 1:
The patent implements preliminary action by having primary transmitters periodically broadcast their location and transmission power information before secondary users need to access frequencies. Spectrum sensors pre-acquire and store sensing information about primary user networks in advance. This allows secondary users to quickly determine frequency access opportunities without performing complex real-time sensing calculations, thus maintaining high accuracy while enabling real-time operation.
Solution Approach 2:
The patent uses copying by having spectrum sensors create copies of primary transmitter information (location, power, frequency) and store them in a database. Instead of requiring every secondary user to perform independent sensing calculations, the system distributes copied sensing information to secondary users, who can then quickly determine frequency access opportunities based on pre-acquired data, significantly reducing calculation complexity while maintaining accuracy.
3Adaptability or versatility
If cognitive radio networks serve low-performance terminals without sensing functions, then network coverage and user access are improved, but the ability to accurately determine frequency access opportunities is reduced
Solution Approach 1:
The patent introduces an intermediary approach where spectrum sensors and a frequency management server act as mediators between primary users and secondary users. Low-performance terminals without sensing functions can still access the network by receiving frequency access opportunity information from the server, which has acquired accurate sensing data from spectrum sensors. This intermediary system maintains measurement precision by relying on professional sensing infrastructure while enabling broad network compatibility.
Solution Approach 2:
The patent implements self-service by enabling secondary users to autonomously determine their frequency access opportunities using received sensing information and server-provided data. Each secondary user can independently calculate whether their transmission will cause harmful interference to primary users based on the provided location, power, and frequency information, without requiring complex sensing capabilities or continuous server intervention, thus supporting low-performance terminals while maintaining accuracy.
Data Source
AI summary
Provided is a device for allocating a dynamic frequency for a secondary user in a cognitive radio network. The device includes: an OP map generation unit for generating an opportunity map, which represents a probability of successful communication of the secondary transmitter in each region of the cognitive radio network, by using one or more of spectrum sensing information, which is received from a spectrum sensor that has completed sensing and includes identifier information, location information, and a sensing measurement matrix, an access request message, which is received from the secondary transmitter and includes identifier information, location information, and operable band information, and the density and transmission powers of primary transmitters; and a response message generation unit for generating a response message, which includes the channel having the highest probability of successful communication and the probability of successful communication, based on the generated map.