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Cognitive radio (CR) is a promising technology to solve the spectrum scarcity problem by enabling secondary users (SU) to utilize the spectrum holes of primary users (PU) caused by static spectrum allocation. However, SUs need to avoid the interference to PUs, imposing new challenges in routing protocol designs and throughput improvement in CR networks (CRN). In this paper we propose a cross-layer...
In this paper, we propose a cross‐layer based power allocation scheme with statistical delay QoS guarantees for the cognitive (secondary) amplify‐and‐forward relay link, which coexists with one primary link by sharing particular portion of the spectrum. Specifically, our derived power allocation scheme aims at maximizing the effective capacity of the cognitive relay link, which can be seen as the...
Spectrum handover becomes one of the hot topics of Cognitive Radio recently. Spectrum handover happens when the primary users and secondary users collide on the same spectrum hole, and the secondary users need to switch to other spectrum holes to continue the communication. Therefore, the reliability of spectrum Q-learning handover, which is reflected by the quality of service of secondary users and...
Cognitive radio is the approach to increase the spectrum utilization for wireless applications. Control channel design is essential to improve the performance of the cognitive radio network. The control channel design scheme of Multi-channel Time domain Identification Rendezvous (MTIR) is proposed which adopts different signal patterns to abate the dependence on network-wide synchronized clock for...
As one of the hot topics in Cognitive Radio, the secondary user's capacity has been paid lots of attentions. The interference incurring in cognitive environment hides more information than current researches have discovered. This paper studies the process that individual primary users and secondary users interfering each other, based on which the capacity of each secondary user on every spectrum hole...
Channel reservation is used to decrease the drop ratio of secondary users caused by spectrum handover. This paper considers the maintainer of the reserved channels in one secondary system coexisting with multiple primary systems. The global channel reservation scheme, the user channel reservation scheme, and the user-updated channel reservation scheme are proposed, derived by different Markov models...
The frequency resource of mobile communication systems is intensive and it needs to combine with cognitive radio technology. The mobile telecommunication system subscribers are sensitive to interference, making the interference problem need prompt solution. This paper analyzes the inter-system and intra-system interference and proposes the approach of utilizing spectrum holes classification. The spectrum...
Spectrum hole has the time-varying characteristic in cognitive radio. The activity of the primary user is one of the concerned factors in time-varying characteristic. Another factor is that the second users, who monitor the activity of the primary user s in different geographic locations, could get various arrival rates of primary users on the same spectrum hole. The third factor is the probability...
A cognitive radio should avoid interference from secondary users to primary users. However, the unknown location of primary receiver makes the problem hard to solve. This paper proposes a novel primary receiver detection to change the passive state of primary receivers. Primary receiver informs the secondary user it's licensed receive frequency according to semaphore architecture via mapping method...
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