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This paper proposes an optimal soft fusion scheme for cooperative spectrum sensing in cognitive radio (CR) network. Multiple cooperative secondary users (SUs) simply serve as relay nodes in the network to provide space diversity for spectrum sensing. An optimal soft fusion scheme of the relayed sensing observations is derived in Neyman-Pearson framework, on the basis of maximizing the deflection coefficient...
The potential interference of ultra wideband (UWB) on existing narrowband wireless communication systems must be analyzed before it is applied, so the paper uses a method based on the physical layer model to analyze the compatibility of direct-sequence ultra wideband (DS-UWB) and multi-band ultra wideband (MB-UWB) on several narrowband victim systems. Based on the physical layer models of PAM-DS-UWB...
To increase the scarcity of spectrum resources and enhance the anti-jamming performance of the system, a novel cognitive frequency hopping mechanism is proposed in the paper. It solves the problem that adaptive frequency hopping can't distinguish between self-interference and interference from other wireless communication systems. The paper explains the mechanism of cognitive frequency hopping and...
This paper addresses the problem of interfering with narrowband licensed users caused by DS-UWB systems. Deducting the colliding frequency band from UWB spectrum, and then employing orthonormal expansion by Hermite-Gaussian functions, the paper develops a low-complexity algorithm for generating DS-UWB signals that adaptively avoid or recover arbitrary colliding bands. A system implementing this algorithm...
Synchronization process is essential especially in UWB communication system owes to its extremely short transmitted pulse shape and the ultra dense multi-path interference. Acquisition performance decreased rapidly own to serious inter-symbol interference (ISI) caused by those complex channel with relatively large delay spread. An interference resistant adaptive threshold acquisition algorithm (IR-ATAA)...
An adaptive pulse in DS-UWB systems is characterized as being able to form nulls around some frequencies as a way to suppress its interference to licensed narrow-band users. This paper proposes an orthonormal expansion method in designing adaptive pulses, using Hermite-Gaussian functions as the orthonormal basis. An algorithm is devised and a case study provided, which shows, while satisfying the...
Ultra-wide band (UWB) radio transmits data using nanosecond level impulses, typically work in dense multi-path environment. Acquisition performance decreases rapidly due to serious inter-symbol interference (ISI) caused by those complex channel with relatively large delay spread. An interference resistant adaptive threshold acquisition algorithm (IR-ATAA) for DS-UWB systems is described and analyzed...
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