Power control method and device for cognitive radio network

Abstract

The invention discloses a power control method and device for a cognitive radio network, wherein the method comprises the steps of constructing a state space model, and calculating a state feedback gain for the state space model through an LMI method; by updating the transmitting power of a secondary user i in a time slot k, the actual measurement signal-to-noise ratio of the secondary user i in the time slot k and the interference of the secondary user i in the time slot k to a primary user l, calculating a secondary user signal-to-noise ratio tracking error in the time slot k and an interference temperature tracking error in the time slot k by combining an error dynamic equation, and selecting a controller according to the positive and negative values, reducing the transmitting power of the secondary user through the controller, controlling the updating instruction according to the fact that the product of the state feedback gain and the input vector of the time slot k is equal to the updating power of the secondary user i, and returning to update again until the transmitting signal of the secondary user does not occupy the frequency spectrum. According to the method, the influence of factors such as near-far effect, fast channel fading, measurement error, multi-access interference and link time delay is considered, and good robust tracking performance is presented through secondary user power control.

Description

technical field [0001] The present invention relates to the technical field of radio networks, in particular to a power control method and device for a cognitive radio network. Background technique [0002] In recent years, with the rapid development of modern wireless communication technology services, limited spectrum resources can no longer meet the growing needs of people. Effectively improving spectrum utilization has become an important topic in the communication field. Cognitive radio can independently search for free spectrum, which can improve the utilization efficiency of spectrum to a certain extent. Compared with existing communication systems (4G, 4.5G), secondary users (SU) and primary users (PU) share licensed frequency bands in underlay cognitive radio networks (CRNs) to improve spectrum utilization. At the same time, this method can be directly built on the mobile wireless network, thereby saving construction costs and reducing network investment. Therefo...

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Problems solved by technology

However, updating the system status of users in the next time slot in the previous time slot based on the power control of the above method in the underlay cognitive network cannot be accurately described in real time

[0004] Furthermore, the limitation of interference temperature is a key constraint to achieve power control in underlying cognitive radio networks, and it is also an important factor to limit dynamic multiplexing and improve spectral efficiency

However, in the above algorithm, the fixed interference temperature threshold is obviously inappropriate for describing the impact of the secondary user on the primary user

At the same time, the actual channel state information is inevitably affected by quantization error, measurement error and uncertain interference, which leads to the degradation of system performance

[0005] Up to now, the power control methods have not included the influence of interference temperature, quantization error, measurement error and uncertain interference into the power control, and there is no good solution to solve the above problems.

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