Abstract: We consider a problem of radio frequency (RF) signal analysis where one sensing node observes a frequency band possibly used by multiple packet based radio transmitters. Analysis of the received signal includes two steps. In the first step we use a spectrogram to perform temporal segmentation of the received nonstationary signal. This task may be formulated as a clustering problem. In the second step we compute a certain 2-D slice of the fourth order spectrum for each of the segments found in the first step. These fourth order spectrum slices are arraigned in a three-way array. One aspect of the second step is to use uniqueness properties of the low rank decomposition of the three-way array to recover spectra and associated activity sequences of individual components in the received signal. We derive a numerical algorithm for the low rank decomposition, which computes estimates of the spectra and activity sequences by optimizing certain weighted least squares criterion under application specific constraints.

Abstract: An access point of a wireless network including: a controller for emulating a first virtual access point of a first service provider and a second virtual access point of second service provider; a transceiver port for communicating control signals to clients of the first and service providers to limit the uplink air-time of the clients; and a connection port for linking the first and second service providers to a backhaul.

Abstract: We consider a problem of radio frequency (RF) signal analysis where one sensing node observes a frequency band possibly used by multiple packet based radio transmitters. Analysis of the received signal includes two steps. In the first step we use a spectrogram to perform temporal segmentation of the received nonstationary signal. This task may be formulated as a clustering problem. In the second step we compute a certain 2-D slice of the fourth order spectrum for each of the segments found in the first step. These fourth order spectrum slices are arraigned in a three-way array. One aspect of the second step is to use uniqueness properties of the low rank decomposition of the three-way array to recover spectra and associated activity sequences of individual components in the received signal. We derive a numerical algorithm for the low rank decomposition, which computes estimates of the spectra and activity sequences by optimizing certain weighted least squares criterion under application specific constraints.

Abstract: A system and method for providing cost-effective broadband mobile services using a hybrid wireless network consisting of wide-area cellular (“3G”) supplemented by hotspot caches are provided. The proposed architecture uses opportunistic access of high-bandwidth wireless hotspot to dramatically reduce the cost per MB of media delivered to mobile end-users. The system also uses a “semantic multicast routing” approach to caching and delivering media based on individual user profiles.

Abstract: A system and method for the delivery of information. A network permits the transfer of small to large data files through a variety of delivery methods, such as physical or electronic means. The information may include different types of media content, which may be selected and retrieved by a user. The user can select the location and time for delivery of the information, which is retrievable and downloadable to a personal device. This allows users to acquire the information in a relatively short period of time and at neighboring locations.