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Abstract-In recent years, cognitive radio (CR) has received a great attention due to the ability to improve the spectrum utilization. It allows the secondary user (SU) in the CR network to opportunistically access the licensed spectrum of the primary user (PU). For this end, quality of service (QoS) requirements for both the PU and the SU should be guaranteed at the same time. These QoSs can be respectively translated into the interference temperature at the primary receiver and the received signalto-interference-plus-noise-ratio (SINR) of the secondary receiver. In such a CR network, a power control can increase the energy efficiency by keeping the transmission power of the SU as low as possible within the QoS requirements.In this paper, we propose an autonomous distributed power control scheme for CR networks that considers the QoS requirements of the PU and the SU simultaneously. Since the transmission power of each SU is constrained so that the interference temperature at the primary receiver caused by all SUs does not exceed the interference tolerance of the PU, the QoS requirement for the PU is always guaranteed. Through the simulation results, we demonstrate that the proposed scheme never exceed the interference tolerance of the PU.Index Terms−Cognitive radio, quality of service, power control, distributed constrained power control, generalized distributed constrained power control

The transmission power and position of the primary user in cognitive radio(CR) is very precious information because these information of the primary user determines the spatial resource. This opportunistic spatial resource is available to secondary users to exploit it. To find position of the primary user, we try to use existing positioning or localization schemes based on ranging techniques but those require the primary user's transmission. Since most primary users in CR are legacy system, and there are no beacon protocol to advertise useful information such as transmission power. Some of existing localization schemes don't require the transmission power, but those don't work in Outer case that the primary user is out of convex hull of secondary users' coordinates. We propose the constrained optimization method to estimate transmission power and position without the prior information of the transmission power. Also, we do extensive simulations on two major cases of network deployments to prove that the proposed constrained optimization method increases performance in mean square error(MSE).

No abstract

This paper considers a dynamic spectrum allocation (DSA) model that a spectrum broker (SB) coordinates the allocation of the spectrum with the regional license inside the region of responsibility. It has a potential to leverage the spectrum utilization but requires a sophisticated approach to manage the allocation-dependent interference effect. Thus, the SB is responsible to manage the wireless interference between base stations (BSs) within the region for quality of service (QoS) provisioning over the allocated channels. In this paper, we address the interference constrained DSA problem and propose an interference management scheme that collaboratively works with the spectrum allocation algorithm to implement the DSA. By the allocation-aware interference management based on the received signal-to-interference-plus-noise-ratio (SINR), the proposed scheme can reflect the context of the SB's decisions at the allocation process. Simulation results demonstrate that the proposed scheme efficiently distributes the spectrum resource while guaranteeing the QoS requirements of all BSs with allocated channels.