With the wireless technology development, more and more standards are declared for certain purpose and many of them have to share the same radio frequency spectrum. On the other hand, because many requests from instable traffic use the peak rate and some behavior of bursted traffic, the utilization of the channel might be low in most of the time. Therefore, the radio frequency spectra are treasurable and issues about increasing or balancing spectrum utilization become more important. CR (Cognitive Radio) technique is now developing for solving this critical problem. CR technique includes many aspects of researches, such as reusing spectrum holes invisibly, learning form users' behavior, adjusting changes form the environment automatically, and so on. This paper gives out a cognitive borrowing algorithm which can ensure the QoS of primary users. By using this algorithm with environment scanning capability, CR traffics raise the utilization of the channel with only rare damage to prior users. Moreover, the algorithm has the advantages of decentralized system, flexibility, low computing complexity, and fairness.
展开▼
