Chapter UWB Cognitive Radios

Management & management technique

Business scenarios, technical challenges and system requirements - D2.1

Deliverable D2.1 del projecte Europeu OneFIT (ICT-2009-257385)Preprin

Preliminary Experimental Results on the Spectrum Sensing Performances for UWB-Cognitive Radios for Detecting IEEE 802.11n Systems

In this paper we present the spectrum sensing performance for detecting the IEEE 802.11n WiFi terminals for Ultra-Wideband (UWB) based Cognitive Radio (CR) systems. The 802.11n WiFi system lies in the 5GHz un-licensed frequency band and is subjected to interferences from the UWB transmissions. The UWB based CR terminals perform secondary communications by opportunistically utilizing the available spectrum when no legacy users such as the 802.11n WiFi systems are present in the environment. Therefore, the CR nodes need to sense the spectrum to detect the presence of any legacy users in the surroundings. Here, we study the commonly known spectrum sensing technique, the energy based method, on experimentally obtained signal data for the IEEE 802.11n WiFi system, and analyze the detection performances for detecting the legacy user. We present the time-frequency measurements obtained from the experimental data, and also compute the probabilities of miss detection and false alarm for detecting the legacy user by performing post analysis on the experimental data.JRC.G.6-Security technology assessmen

Chapter UWB Cognitive Radios

Management & management technique

Spectrum Sensing for Cognitive Radios with Transmission Statistics: Considering Linear Frequency Sweeping

The spectrum sensing performance of Cognitive Radios (CRs) considering noisy signal measurements and the time domain transmission statistics of the Primary User (PU) is considered in this paper. When the spectrum is linearly swept in the frequency domain continuously to detect the presence of the PU the time-domain statistics of the PU plays an important role in the detection performance. This is true especially when the PU's bandwidth is much smaller than the CR's scanning frequency range. We model the transmission statistics that is the temporal characteristics of the PU as a Poisson arrival process with a random occupancy time. The spectrum sensing performance at the CR node is then theoretically analyzed based on noisy envelope detection together with the time domain spectral occupancy statistics. The miss detection and false alarm probabilities are derived from the considered spectral occupancy model and the noise model, and we present simulation results to verify our theoretical analysis. We also study the minimum required sensing time for the wideband CR to reliably detect the narrowband PU with a given confidence level considering its temporal characteristics

Baysian tracking in cooperative localization for cognitive radio networks

In this paper we consider cooperative localization and tracking of primary users (PU) in a cognitive radio network using Bayesian techniques. We use particle filtering methods to track the location of a PU in the network using cooperative localization techniques and present some results for noisy measurements. The cognitive radio (CR) nodes estimate the information related to the geographical position of the PU based on existing location identification and localization techniques and forward the noisy information to a cognitive radio base station (CRB), which then fuses the information to estimate the position of the PU in the network in order to perform a radio scene analysis. We propose a particle filtering approach that is suitable for tracking Gaussian and non-Gaussian noisy signals at the CRB to estimate the position of a PU, two importance-functions relative to the particle filtering algorithm are also presented. Simulations are performed on the proposed tracking algorithm and the results are presented in terms of the mean squared error of the positional estimates.5 page(s

Spectrum Sensing for Cognitive Radios with Transmission Statistics: Considering Linear Frequency Sweeping

The spectrum sensing performance of Cognitive Radios (CRs) considering noisy signal measurements and the time domain transmission statistics of the Primary User (PU) is considered in this paper. When the spectrum is linearly swept in the frequency domain continuously to detect the presence of the PU the time-domain statistics of the PU plays an important role in the detection performance. This is true especially when the PU's bandwidth is much smaller than the CR's scanning frequency range. We model the transmission statistics that is the temporal characteristics of the PU as a Poisson arrival process with a random occupancy time. The spectrum sensing performance at the CR node is then theoretically analyzed based on noisy envelope detection together with the time domain spectral occupancy statistics. The miss detection and false alarm probabilities are derived from the considered spectral occupancy model and the noise model, and we present simulation results to verify our theoretical analysis. We also study the minimum required sensing time for the wideband CR to reliably detect the narrowband PU with a given confidence level considering its temporal characteristics.</p