Interference temperature measurements and spectrum occupancy evaluation in the context of cognitive radio

This paper presents a refined radio spectrum measurement platform specifically designed for spectrum occupancy surveys in the context of Cognitive radio. Cognitive radio permits the opportunistic usage of licensed bands by unlicensed users without causing harmful interference to the licensed user. In this work, a study based on the measurement of the 800 MHz to 2.4 GHz frequency band at two different locations inside Universiti Teknologi Malaysia (UTM), Johor Bahru campus, Malaysia is presented. Two Tektronix RSA306B spectrum analyzer are set up to conduct simultaneous measurements at different locations for a 24 hours period. The analysis conducted in this work is based on the real spectrum data acquired from environment in the experimental set up. Busy and idle channels were identified. The channels subject to adjacent-channel interference were also identified, and the impact of the detection threshold used to detect channel activities was also discussed. The consistency of the observed channel occupation over a range of thresholds and a sudden drop has good characteristics in determining an appropriate threshold needed in order to avoid interference

Evaluación del nivel de utilización del espectro: Posibilidades de la tecnología cognitive radio en España

Cognitive radio has been identified as a promising solution to the so-called spectrum scarcity problem. The basic idea of this paradigm is to allow unlicensed users to access in an opportunistic and non-interfering manner some licensed bands temporarily unoccupied by licensed users. Cognitive radio is expected to dramatically improve the efficiency of spectrum usage. However, before this paradigm can turn into reality, a full understanding of the spectrum dynamic usage in real wireless communications systems is required. Current spectrum utilization has already been evaluated in some measurement campaigns all over the world. However, to the best of the authors’ knowledge, no previous study has assessed the spectrum occupancy and the feasibility of the cognitive radio technology in different allocated spectrum bands under Spanish regulations. In this context, this paper presents a pioneer spectrum occupancy measurement in Spain conducted in the frequency range from 75 MHz to 7075 MHz in an outdoor environment in urban Barcelona. The measurements are analyzed and compared to the official spectrum regulations. The obtained results demonstrate the existence of a significant amount of spectrum available for the deployment of future cognitive radio networks.Postprint (published version

A Multi-dimensional Real World Spectrum Occupancy Data Measurement and Analysis for Spectrum Inference in Cognitive Radio Network

Spectrum Inference in contrast to Spectrum Sensing is an active technique for dynamically inferring radio spectrum state in Cognitive Radio Networks. Efficient spectrum inference demands real world multi-dimensional spectral data with distinct features. Spectrum bands exhibit varying noise floors; an effective band wise noise thresholding guarantees an accurate occupancy data. In this work, we have done an extensive real world spectrum occupancy data measurement in frequency range 0.7 GHz to 3 GHz for tele density wise varying locations at Pune, Solapur and Kalaburagi with time diversity ranging from 2 to 7 days. We have applied maximum noise (Max Noise), m-dB and probability of false alarm (PFA) noise thresholding for spectrum occupancy calculations in all bands and across all locations. Overall occupancy across these locations is 37.89 %, 18.90 % and 13.69 % respectively. We have studied signal to noise ratio (SNR), channel vacancy length durations (CVLD) and service congestion rates (SCR) as characteristic features of measured multi-dimensional spectrum data. The results reveal strong time, spectral and spatial correlations of these features across all locations. These features can be used for a multi-dimensional spectrum inference in cognitive radio based on machine learning

DETEKSI SINYAL SPECTRUM SENSING MENGGUNAKAN NILAI EIGEN PADA COGNITIVE RADIO

Cognitive Radio adalah sebuah sistem yang dapat memahami lingkungan komunikasinya dan dapat mengatur parameternya secara optimal dalam melakukan proses komunikasi. Dengan teknologi ini Secondary User dapat mengisi spectrum hole Primary User yang sedang tidak digunakan tanpa mengakibatkan gangguan. Salah satu fungsi utama dari Cognitive Radio adalah Spectrum Sensing. Fungsi inilah yang akan mendeteksi semua spectrum hole agar bisa dipakai nantinya. Salah satu metode spectrum sensing ini adalah Deteksi Energi. Tetapi karena Deteksi Energi masih sensitif dengan ketidakpastian noise maka dibutuhkan metode lain untuk menunjang performansi metode ini, yaitu dengan menggunakan Nilai Eigen. Nilai Eigen, sinyal dan noise umumnya berbeda. Dengan demikian, perbedaan ini dapat digunakan dalam metode ini untuk membedakan sinyal dari noise. Metode sensing yang diusulkan ini diharapkan memperbaiki kekurangan dari Deteksi Energi masalah tersebut. Tugas Akhir ini menganalisis kinerja dan membandingkan dua metode yaitu, Deteksi Energi menggunakan Nilai Eigen. Sinyal Primary User akan dibangun menggunakan OFDM yang nantinya akan ditransmisikan melalui kanal yang terdistribusi oleh hamburan Rayleigh dan ditambahkan oleh Additive White Gaussian Noise (AWGN). Setelah itu sinyal yang diterima oleh secondary user (SU) menggunakan single detector yang setelahnya disampling dengan jumlah sampel untuk dihitung Nilai Eigen dari matriks tersebut. Kemudian akan dibandingkan kinerja deteksi kedua metode tersebut menggunakan Kurva Receiver Operating Characteristic (ROC). Hasil yang dapat diambil dari hasil simulasi ini adalah, Nilai Eigen mempunyai kemampuan deteksi yang lebih baik dibanding dari Deteksi Energi, karena Nilai Eigen tidak terpengaruh oleh ketidakpastian noise, sehingga dapat mendeteksi spectrum hole di PU lebih akurat. Kinerja dari Metode Nilai Eigen akan terus meningkat bila menggunakan jumlah antena 16 ataupun 32. Bila Semakin besar nilai Signal-to-Noise Ratio (SNR), maka probability of detection dari Nilai Eigen juga membesar. Probability of detection ketika SNR -2 dB akan lebih baik daripada SNR -8dB. Kata kunci: Cognitive Radio, Deteksi Energi, spectrum sensing, threshold, Nilai Eigen

ESTUDIO DE OCUPACIÓN ESPECTRAL DE SERVICIOS DE COMUNICACIÓN DE 85 MHZ A 2.5 GHZ EN SAN LUIS POTOSÍ, MÉXICO (SPECTRUM OCCUPANCY MEASUREMENTS ON COMMUNICATION SERVICES FROM 85 MHZ TO 2.5 GHZ IN SAN LUIS POTOSI, MEXICO)

El espectro radioeléctrico es un recurso limitado para las comunicaciones inalámbricas, en México este es administrado por el Instituto Federal de Telecomunicaciones (IFT) el cual asigna las frecuencias que van desde los 3 kHz hasta los 300 GHz. El hecho de que todo este ancho de banda este atribuido para ser usado en ciertos servicios de comunicación no significa que todas las bandas sean utilizadas en determinado momento y lugar.  Con el fin de determinar la ocupación real del espectro radioeléctrico en determinadas bandas, se realizó una campaña de medición espectral en la ciudad de San Luis Potosí utilizando tres distintos umbrales de decisión propuestos en la literatura. En este trabajo se presenta la metodología utilizada para la realización de dicha campaña, así como del cálculo del umbral de decisión y ciclo de trabajo de cada banda. Los resultados muestran que el ciclo de trabajo en las bandas de estudio varía en relación con el umbral de decisión utilizado, además de que la ocupación depende del tipo de servicio ofrecido en cada banda.Radioelectric spectrum is a limited resource for wireless communication, in Mexico it is managed by the Federal Telecommunication Institute whom allocate frequencies between 3 kHz and 300 GHz, the fact that this whole bandwidth is reserved for its use in certain communication services does not mean that all bands will be used at a particular time and place. In order to measure the real spectrum occupancy in certain bands, a spectrum measurement campaign was held in the city of San Luis Potosi, three different decision thresholds were used in this paper. In this paper we present the methodology used in this campaign, also decision threshold and duty cycle calculation are explained. Results show that duty cycle in the studied bands vary depending on decision threshold used, also we conclude that spectrum occupancy depends on the kind of service offered in the band

Ocupación espectral de la banda ISM de 2.4 GHz para aplicaciones de radio cognoscitivo

La tecnología de radio cognoscitivo representa una prometedora solución al problema de escasez de espectro electromagnético, dado que una gran parte del espectro asignado se utiliza de forma esporádica, existiendo una subutilización del mismo. En la banda industrial, científica y médica (ISM, por sus siglas en inglés) de 2.4 GHz, varias campañas de mediciones se han realizado para determinar la ocupación real del espectro. En este trabajo se describe una metodología para obtener la ocupación espectral de la banda ISM de 2.4 GHz, en las instalaciones de la Facultad de Ciencias en la Universidad Autónoma de San Luis Potosí. Se presentan los resultados de la densidad espectral de potencia y el ciclo de trabajo. Estos resultados indican claramente que la utilización del espectro es baja, a pesar de que muchas tecnologías de comunicación inalámbrica comparten este recurso.Palabras Claves: banda ISM, ciclo de trabajo, ocupación espectral, radio cognoscitivo

EVALUATION OF SPECTRUM OCCUPANCY AND COMPARISON FOR THREE DIFFERENT REGIONS

Radio spectrum is a scarce source and very significant to measure and monitor. The present spectrum must be exploited efficiently since every new application must be allocated to spectrum. With purpose of using the spectrum efficiently, there are worldwide research efforts on dynamic spectrum access. Among these methods, cognitive radio mostly draws attention. In order to carry out dynamic spectrum access studies successfully, available spectrum must be meticulously analyzed. In this paper, spectrum occupancy measurements between 25-3000 MHz frequency bands were made in three different regions (Selçuklu, Karatay, Meram) of Konya, Turkey in outdoors during six months. Obtained data is presented with graphics. The occupancy ratios are %5.12, %4.46 and %4.19 for Selçuklu, Karatay and Meram, respectively

Modelo de decisión del espectro para radio cognitiva que integra las pérdidas de propagación en la banda GSM del espectro radioeléctrico

Esta tesis en una investigación enmarcada dentro de la tecnología de la radio cognitiva, específicamente en la etapa de decisión del espectro, donde se selecciona(n) la(s) banda(s) más apropiada(s) para la transmisión con base en la información recopilada durante la etapa de detección del espectro y los requerimientos de los usuarios no licenciados, para esto se aplico un modelo de decisión a través de las técnicas de selección por análisis multicriterio. Dentro de este desarrollo se efectuaron mediciones en tres puntos de la ciudad de Bogotá durante un total de trece días. Con los resultados obtenidos se diseñó un modelo de decisión del espectro que integra, dentro de sus parámetros de decisión, las pérdidas de propagación en la banda GSM dentro de Bogotá y permite hacer un uso un 26% más eficiente del espectro.This research thesis is framed within the cognitive radio technology, specifically in the spectrum decision step from the cognitive cycle, where is selected the most suitable band for transmission, based on the information gathered during the step before of detecting the spectrum and the requirements of non-licensed users, then the decision model was developed through multiple-criteria decision analysis. Within this development were made measurements at three points in Bogota for a total of thirteen days. The main result was a decision model that integrates propagation loss within its decision parameters, in the GSM band and allows us to use the spectrum an 26% more efficiently

Implementation of cognitive radio networks to evaluate spectrum management strategies in real-time

This paper illustrates a Universal Software Radio Peripheral (USRP)-based real-time testbed that is able to evaluate different spectrum management solutions that exploit the Cognitive Radio (CR) paradigm. The main objective of this testbed is to provide an accurate and realistic platform by which the performance of innovative spectrum management solutions for a wide set of scenarios and use cases in the context of Opportunistic Networks (ONs) and Cognitive Radio Networks (CRNs) can be entirely validated and assessed before their implementation in real systems. Real-time platforms are essential to carry out significant studies and to accurately assess the performance of innovative solutions before their implementation in the real world. This work provides a comprehensive description of the testbed, highlighting many interesting implementation details and illustrating its applicability for different studies that rely on the CR paradigm. Then, a particular application in a realistic Digital Home (DH) scenario is also illustrated, which allows demonstrating the effectiveness of the real-time testbed and assessing its practicality in terms of user-perceived end-to-end Quality of Experience (QoE) in a realistic environment.Peer ReviewedPostprint (author's final draft