An Opportunistic Spectrum Access Method Based on Three-State Learning Strategy in Cognitive Radio

Abstract

The invention discloses a chance frequency spectrum access method based on the tri-state learning strategy and in cognitive radio. The method includes that a cognitive user conducts fit goodness test on a current target information channel. A detection result in each time slot includes three states: the free state, the occupation state and the transition state. Suppose that the free state and the occupation state of a main user submit to the exponential distribution, and the cognitive user utilizes a hidden markov model to dynamically adjust information channel utilization parameter of the main user. The cognitive user utilizes estimation parameter to calculate change frequency spectrum access information channel capacity and determines to select the current information channel or enter the next information channel. The cognitive user updates the current confidence vectors according to the markov decision-making process which is partially observable and determines whether to send data at the time slot. The chance frequency spectrum access method based on the tri-state learning strategy can effectively improve information channel utilization rate of the cognitive user, accurately reflects true state of an authorization information channel accordingly, remarkably reduces delay when the information channel is accessed or quits, and simultaneously reduces interference of the main user.

Description

technical field [0001] The invention relates to the technical field of radio channel access, in particular to an opportunistic spectrum access method based on a three-state learning strategy in cognitive radio. Background technique [0002] Cognitive Radio (CR), as an intelligent wireless communication technology, can effectively improve the frequency band utilization of licensed channels. A complete cognitive cycle usually includes four aspects: spectrum sensing, autonomous learning, channel selection, and channel access. Opportunist Spectrum Access (OSA) can ensure that cognitive users can access authorized channels while avoiding interference to primary users. Since the cognitive user cannot know the real state of the primary user, the licensed frequency band can only be detected through spectrum sensing technology. Cognitive users update the confidence vector according to the detection results and decide whether to access the authorized channel. [0003] However, beca...

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Problems solved by technology

[0003] However, because the existing channel access method does not introduce a learning strategy, the cognitive user cannot track the change of the channel parameters, nor can it select the channel according to the estimated parameters; at the same time, the detection result of the cognitive user for each time slot only includes two Two states: idle and occupied, without considering the possible switching between idle and occupied states in practice, which will cause cognitive users to waste a large number of spectral holes

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