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To facilitate a functional analysis of neuronal connectivity in a mammalian nervous system that is tightly packed with billions of cells, we developed a new technique that uses inducible genetic manipulations in fluorescently labeled single neurons in mice. Our technique, single-neuron labeling with inducible Cre-mediated knockout (SLICK), is achieved by(More)
Wireless multi carrier approaches can support the simultaneous transmissions to several wireless terminals, each one getting only some of the available subcarriers. Judiciously assigning subcarriers to terminals can be used to, e.g., increase the capacity of a wireless cell; however, the resulting assignment problem is difficult. The first subproblem is to(More)
In this paper, we study the performance of a combined linkand physical-layer approach for the downlink of a dynamic OFDM-FDMA transmission system delivering MPEG-4 video streams. The approach consists of three different mechanisms — queue management, resource allocation, and subcarrier assignment — which can be used separately as well as in combination.(More)
In this paper we review contributions regarding dynamic, i.e., channel-state adaptive schemes for OFDM systems. As the wireless broadband channel is frequency-selective, the OFDM transmission scheme provides an efficient technique to overcome this impairment. However, the OFDM transmission scheme provides further advantages. Various system metrics can be(More)
James Gross, Hans-Florian Geerdes, Holger Karl, Adam Wolisz Telecommunication Networks Group, Technische Universitaet Berlin Einsteinufer 25, 10587 Berlin, Germany Phone: +49 30 31423830, E-mail: {gross,wolisz}@tkn.tu-berlin.de Zuse Institute Berlin (ZIB) Takustr. 7, 14195 Berlin, Germany Phone: +49 30 84185278, E-mail: geerdes@zib.de Institute of Computer(More)
In wireless local area networks often a station can potentially associate with more than one access point. Therefore, a relevant question is which access point to select "best" from a list of candidate ones. In IEEE 802.11, the user simply associates to the access point with the strongest received signal strength. However, this may result in a significant(More)
Recently, a lot of research effort has been spent on cross-layer system design. It has been shown that cross-layer mechanisms (i.e., policies) potentially provide significant performance gains for various systems. In this article we review several aspects of cross-layer system optimization regarding wireless OFDM systems. We discuss basic optimization(More)
One of the key challenges of the emerging Cognitive Radio based IEEE 802.22 Wireless Regional Area Networks (WRAN) is to address two apparently conflicting requirements: assuring QoS satisfaction for WRAN services, while providing reliable spectrum sensing for guaranteeing licensed user protection. To perform reliable sensing, in the basic operation mode on(More)
One of the key challenges of the emerging Cognitive Radio based IEEE 802.22 Wireless Regional Area Networks (WRAN) is to address two apparently conflicting requirements: assuring QoS satisfaction for WRAN services, while providing reliable spectrum sensing for guaranteeing licensed user protection. To perform reliable sensing, in the basic operation mode on(More)