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Articles 1 - 3 of 3
Full-Text Articles in Computer Engineering
Transparent Spectrum Co-Access In Cognitive Radio Networks, Jonathan Daniel Backens
Transparent Spectrum Co-Access In Cognitive Radio Networks, Jonathan Daniel Backens
Electrical & Computer Engineering Theses & Dissertations
The licensed wireless spectrum is currently under-utilized by as much as 85%. Cognitive radio networks have been proposed to employ dynamic spectrum access to share this under-utilized spectrum between licensed primary user transmissions and unlicensed secondary user transmissions. Current secondary user opportunistic spectrum access methods, however, remain limited in their ability to provide enough incentive to convince primary users to share the licensed spectrum, and they rely on primary user absence to guarantee secondary user performance. These challenges are addressed by developing a Dynamic Spectrum Co-Access Architecture (DSCA) that allows secondary user transmissions to co-access transparently and concurrently with primary …
Spectrum Map And Its Application In Cognitive Radio Networks, Saptarshi Debroy
Spectrum Map And Its Application In Cognitive Radio Networks, Saptarshi Debroy
Electronic Theses and Dissertations
Recent measurements on radio spectrum usage have revealed the abundance of underutilized bands of spectrum that belong to licensed users. This necessitated the paradigm shift from static to dynamic spectrum access. Cognitive radio based secondary networks that utilize such unused spectrum holes in the licensed band, have been proposed as a possible solution to the spectrum crisis. The idea is to detect times when a particular licensed band is unused and use it for transmission without causing interference to the licensed user. We argue that prior knowledge about occupancy of such bands and the corresponding achievable performance metrics can potentially …
Efficient Cooperative Mimo Paradigms For Cognitive Radio Networks, Wei Chen, Liang Hong, Xiaoqian Chen
Efficient Cooperative Mimo Paradigms For Cognitive Radio Networks, Wei Chen, Liang Hong, Xiaoqian Chen
Computer Science Faculty Research
This paper investigates the benefits that cooperative communication brings to cognitive radio networks. We focus on cooperative Multiple Input Multiple Output (MIMO) technology, where multiple distributed single-antenna secondary users cooperate on data transmission and reception. Three cooperative MIMO paradigms are proposed to maximize the diversity gain and significantly improve the performance of overlay, underlay and interweave systems. In the paradigm for overlay systems the secondary users can assist (relay) the primary transmissions even when they are far away from the primary users. In the paradigm for underlay systems the secondary users can share the primary users’ frequency resources without any …