The Experts below are selected from a list of 27381 Experts worldwide ranked by ideXlab platform

Danda B. Rawat - One of the best experts on this subject based on the ideXlab platform.

  • INFOCOM Workshops - Group-query-as-a-service for secure dynamic Spectrum access in geolocation-enabled Database-driven opportunistic wireless communications in ROAR framework
    IEEE INFOCOM 2018 - IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), 2018
    Co-Authors: Abdulhamid Adebayo, Danda B. Rawat, Moses Garuba
    Abstract:

    Dynamic Spectrum access is regarded as an emerging approach to enhance the RF Spectrum utilization in future cognitive wireless networks where unlicensed secondary users sense RF channels (that are licensed to primary users) to find idle channels to use opportunistically without creating any harmful interference to primary users. Recently, the US Federal Communications Commission (FCC) mandated that all unlicensed secondary users must query a Spectrum Database for channel opportunities instead of sensing by themselves to avoid any channel sensing uncertainties and harmful interference to primary users. However, Database query process for secondary users could overwhelm the communication channel when there are many users requesting the same information. This excessive number of queries by numerous secondary users could lead to a denial-of-service attack at the Spectrum Database server. In this paper, we investigate a Group-Query-as-a-Service for dynamic Spectrum access in geolocation-enabled Database-driven ROAR (near real-time opportunistic Spectrum access in cognitive radio network) framework. In a Group-Query-as-a-Service approach, secondary users form a group based-on location based grids and a limited number of secondary users of the given group, known as grid leaders, query the Spectrum Database and let other follower secondary users know about the idle channels. Grid leaders are selected based on their past level of interactions and trust they have in the group or grid. Grid leaders query the Database on behalf of other secondary users periodically to get the updated idle channel information. Note that when a new user joins the grid, instead of querying the Database, it gets the idle channel information from the grid leaders. To avoid any outliers in the grid, we use the majority voting among grid leaders. We evaluate the performance of the proposed approach using numerical results obtained from Monte Carlo simulations and numerical results show that the performance of the query process can be significantly enhanced with Group-Query-as-a-Service.

  • CNS - Aggregated-Query-as-a-Secure-Service for RF Spectrum Database-Driven Opportunistic Wireless Communications
    2018 IEEE Conference on Communications and Network Security (CNS), 2018
    Co-Authors: Abdulhamid Adebayo, Danda B. Rawat, Moses Garuba, Laurent Njilla
    Abstract:

    The US Federal Communications Commission (FCC) has recently mandated the Database-driven dynamic Spectrum access where unlicensed secondary users search for idle bands and use them opportunistically. The Database-driven dynamic Spectrum access approach is regarded for minimizing any harmful interference to licensed primary users caused by RF channel sensing uncertainties. However, when several secondary users (or several malicious users) query the RF Spectrum Database at the same time, Spectrum server could experience denial of service (DoS) attack. In this paper, we investigate the Aggregated-Query-as-a-Secure-Service (AQaaSS) for querying RF Spectrum Database by secondary users for opportunistic wireless communications where selected number of secondary users aka grid leaders, query the Database on behalf of all other secondary users, aka grid followers and relay the idle channel information to grid followers. Furthermore, the grid leaders are selected based on their both reputation or trust level and location in the network for the integrity of the information that grid followers receive. Grid followers also use the weighted majority voting to filter out comprised information about the idle channels. The performance of the proposed approach is evaluated using numerical results. The proposed approach gives lower latency (or same latency) to the secondary users and lower load (or same load) to the RF Spectrum Database server when more number of secondary users (or less number of secondary users) query than that of the server capacity.

  • SmartCloud - Location-Based Lightweight Security Scheme for Wireless Communications in ROAR Architecture
    2017 IEEE International Conference on Smart Cloud (SmartCloud), 2017
    Co-Authors: Sean Grant, Abdulhamid Adebayo, Danda B. Rawat, Moses Garuba, Rajni Goel
    Abstract:

    Dynamic Spectrum access is considered to be an emerging technology for enhancing RF Spectrum efficiency where secondary unlicensed users access primacy licensed RF bands in an opportunistic manner for wireless communications. In dynamic Spectrum access, RF Spectrum geolocation Database-driven approach has relieved the wireless devices from uncertainties caused by Spectrum sensing at low signal levels. However, because of the openness in dynamic Spectrum access environment, malicious users could mislead the overall communication resulting in no wireless services to legitimate secondary users. For instance, when secondary user queries the RF Spectrum Database, it sends a query along with its geolocation which could be intercepted and hijacked by the malicious users and block the secondary users from using available RF Spectrum. To address this problem, we have developed a lightweight security technique where hash of a geolocation of the secondary user is used as a part of an encryption key to provide security in the Real-time Opportunistic Spectrum Access in Cloud-assisted Cognitive Radio Networks (ROAR) architecture. The proposed location-based lightweight security scheme leverages the secondary user's location (latitude, longitude and altitude) information to encrypt the data being transmitted to protect the system from possible malicious attacks. This approach has two stages: first, share the unique hash value generated using location information (i.e., longitude, latitude and altitude) secretly with the help of a pre-shared string with the ROAR's geolocation Spectrum server. Second, the secondary users use their hash values obtained by using location information to encrypt the message being transmitted to their corresponding receivers. A key feature of this approach is that if a third party (malicious user) tries to send data to the geolocation Spectrum Database for querying the RF Spectrum Database, malicious actions will be detected and malicious users would not get the service for dynamic Spectrum access. We evaluate the proposed approach using Monte Carlo simulations and experiments using software defined radios in ROAR architecture.

  • CCNC - ROAR: An architecture for Real-Time Opportunistic Spectrum Access in Cloud-assisted Cognitive Radio Networks
    2016 13th IEEE Annual Consumer Communications & Networking Conference (CCNC), 2016
    Co-Authors: Danda B. Rawat
    Abstract:

    Need for Radio Frequency (RF) Spectrum is increasing along with increasing wireless subscriptions and devices that is causing scarcity in total available RF Spectrum. Opportunistic Spectrum access in cognitive radio networks is emerging for maximizing the RF Spectrum efficiency where unlicensed Secondary Users (SUs) access idle Spectrum bands without causing any harmful interference to licensed Primary Users (PUs). All SUs are required to scan/sense RF Spectrum to find idle bands or search for idle bands in a Spectrum Database not to interfere with PUs while using those idle bands. In this paper, we propose a Real-time Opportunistic Spectrum Access in Cloud-assisted Cognitive Radio Networks (ROAR) architecture where SUs (i.e., USRP wireless devices) are equipped with wide-band (50 MHz – 6 GHz) antenna and GPS units. ROAR uses cloud computing platform for real-time processing of wide-band data since SUs' performance is considerably constrained by their limited power, memory and computational capacity. In ROAR architecture, there are two parts: Spectrum sensing to create a Database of idle channels and dynamic Spectrum access for opportunistic SU communications using idle channels. For the Spectrum Database, RF sensors scan/sense RF bands to find idle bands and report the geo-location of idle band, channel frequency and time stamp to the Database installed in the distributed cloud platform. For opportunistic Spectrum access, each SU interested for opportunistic communication queries a Spectrum Database to find idle channels. Distributed cloud computing is used to find idle channels for the SU where geolocation and other demands (e.g., data rate) are checked to find whether the SU is admissible or not for a given geo-location and time. If the SU is admissible based on the admissibility criteria, Spectrum server sends the list of channels available for a given location and time to the SU. Then SU chooses the best suited channel to communicate opportunistically. We evaluate the ROAR architecture using numerical results obtained from extensive experiments.

  • Resource Allocation in Spectrum Overlay Cognitive Radio Networks
    Dynamic Spectrum Access for Wireless Networks, 2015
    Co-Authors: Danda B. Rawat, Min Song, Sachin Shetty
    Abstract:

    Opportunistic Spectrum access (OSA) is an emerging concept for Spectrum overlay based Spectrum sharing model where SUs identify Spectrum opportunities in licensed bands and use them opportunistically without interfering with PUs [12, 20, 34, 36]. In Spectrum overlay approach, as SUs are not allowed to co-exists with PUs in the same channel, they are required to either sense Spectrum to find idle channels or search for idle channels in Spectrum Database [1, 8, 27]. Spectrum Database can maintain geolocations of idle bands and provide a global view on entire frequencies which could be used to find best suitable channels for the SUs. Based on the global view of wideband RF regime, SUs could be granted a channel that has more adjacent channels so that SUs could implement channel bonding for higher data rates [13]. To prepare and update the Spectrum Database, Database server can get Spectrum occupancy information from PUs’ infrastructure (e.g. base stations or access points) in a real-time basis. Alternatively, Spectrum sensors (e.g., crowd sourcing for sensing [9, 38]) could be deployed to collect information about channel status. Based on the collected information, Spectrum server can process data (with the help of cloud computing platform) to create a Spectrum maps for Spectrum opportunities for different wireless networks such as satellite, WiMAX, Wi-Fi, cellular, TV, etc. Spectrum servers could be associated with a single or multiple Spectrum brokers. When a SU wants to access Spectrum opportunities, it searches the geolocation Database for idle bands. If there is an idle band available in given location and time, SU would access it. Otherwise, the SU has to wait until it finds Spectrum opportunities that meets its needs.

Masahiro Morikura - One of the best experts on this subject based on the ideXlab platform.

  • Exclusive Region Design for Spatial Grid-Based Spectrum Database: A Stochastic Geometry Approach
    IEEE Access, 2018
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    This paper presents the stochastic-geometry analysis and designs a primary exclusive region (PER) for a spatial grid-based Spectrum Database system. The purpose of the spatial grid is to utilize information, such as the primary receiver (PR) antenna pattern, and the secondary transmitter (ST) density and transmission power, in each divided region. This paper introduces polar and square grids. For these spatial grids, the cumulants of the aggregate interference at a PR, from the STs, are derived, where the probability generating functional for the Poisson point process (PPP) is used on the assumption that the distribution of the STs in each divided region follows an inhomogeneous PPP. In addition, by introducing the allowable transmission probability of STs in each divided region, the PER optimization problem can be formulated as a continuous optimization problem. Numerical results demonstrate that a PER, corresponding to the information, is successfully designed and that more detailed information, due to a reduction in the area of each divided region, leads to a smaller and complex-shaped PER.

  • stochastic geometry analysis of spatial grid based Spectrum Database
    Vehicular Technology Conference, 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) can experience harmful interference due to unexpected propagation paths, even when the secondary user (SU) follows the Spectrum sharing policy stored in a Database, during operations. A framework for deriving the optimal radius of a circular primary exclusive region (PER) has been proposed. However, a practical PER can be non-circular and should be designed on the basis of the geographical information and directivity of the PU antenna. To design a non-circular PER, in this paper, we introduce a spatial grid-based Spectrum Database; the Database permits or forbids SU transmissions for each annular sector divided by a spatial grid. Considering the random locations of the SUs on each annular sector as an inhomogeneous Poisson point process, we analytically derive the PU's outage probability (OP) using stochastic geometry, where the PU's OP is defined as the probability that the aggregate interference power at a PU, from the SUs, exceeds a threshold. Numerical results show that a non- circular PER results in a lower PU OP compared to a circular PER.

  • Optimization of primary exclusive region in spatial grid-based Spectrum Database using stochastic Geometry
    2017 IEEE International Conference on Communications (ICC), 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) may experience harmful interference caused by unpredictable propagation paths, even when secondary users (SUs) follow a Spectrum sharing policy established on the basis of a Database. A framework for determining the optimal radius of a circular primary exclusive region (PER) on the basis of SU's information has been proposed. However, a practical PER can be complex-shaped and should be designed on the basis of the directivity of the PU antenna, and the SU information in each region. In this paper, we present a stochastic geometry analysis in a spatial grid-based Spectrum Database, and propose a design for an optimal complex-shaped PER. The Database determines the transmission probability of the SUs on each divided annular sector. By regarding the SU's locations on each annular sector as an inhomogeneous Poisson point process, we analytically derive a PU's outage probability (OP), where the PU's OP is defined as the probability that the aggregate interference power at a PU from the SUs exceeds a threshold. Using the derived expression, we formulate an optimization problem to maximize the number of transmitting SUs, which optimizes the SU's transmission probability on each annular sector. Then, we numerically evaluate the solution of the optimization problem in various scenarios. The results show that the accuracy of the PER improves as the grid size decreases. In addition, we successfully design a complex-shaped PER with holes in which the SUs are permitted to transmit.

  • VTC Spring - Stochastic Geometry Analysis of Spatial Grid-Based Spectrum Database
    2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) can experience harmful interference due to unexpected propagation paths, even when the secondary user (SU) follows the Spectrum sharing policy stored in a Database, during operations. A framework for deriving the optimal radius of a circular primary exclusive region (PER) has been proposed. However, a practical PER can be non-circular and should be designed on the basis of the geographical information and directivity of the PU antenna. To design a non-circular PER, in this paper, we introduce a spatial grid-based Spectrum Database; the Database permits or forbids SU transmissions for each annular sector divided by a spatial grid. Considering the random locations of the SUs on each annular sector as an inhomogeneous Poisson point process, we analytically derive the PU's outage probability (OP) using stochastic geometry, where the PU's OP is defined as the probability that the aggregate interference power at a PU, from the SUs, exceeds a threshold. Numerical results show that a non- circular PER results in a lower PU OP compared to a circular PER.

  • ICC - Optimization of primary exclusive region in spatial grid-based Spectrum Database using stochastic Geometry
    2017 IEEE International Conference on Communications (ICC), 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) may experience harmful interference caused by unpredictable propagation paths, even when secondary users (SUs) follow a Spectrum sharing policy established on the basis of a Database. A framework for determining the optimal radius of a circular primary exclusive region (PER) on the basis of SU's information has been proposed. However, a practical PER can be complex-shaped and should be designed on the basis of the directivity of the PU antenna, and the SU information in each region. In this paper, we present a stochastic geometry analysis in a spatial grid-based Spectrum Database, and propose a design for an optimal complex-shaped PER. The Database determines the transmission probability of the SUs on each divided annular sector. By regarding the SU's locations on each annular sector as an inhomogeneous Poisson point process, we analytically derive a PU's outage probability (OP), where the PU's OP is defined as the probability that the aggregate interference power at a PU from the SUs exceeds a threshold. Using the derived expression, we formulate an optimization problem to maximize the number of transmitting SUs, which optimizes the SU's transmission probability on each annular sector. Then, we numerically evaluate the solution of the optimization problem in various scenarios. The results show that the accuracy of the PER improves as the grid size decreases. In addition, we successfully design a complex-shaped PER with holes in which the SUs are permitted to transmit.

Takeo Fujii - One of the best experts on this subject based on the ideXlab platform.

  • ICOIN - Wireless System Selection with Spectrum Database for IoT
    2021 International Conference on Information Networking (ICOIN), 2021
    Co-Authors: Soraya Mitate, Takeo Fujii, Yudai Yamazaki, Shusuke Narieda
    Abstract:

    In recent years, Long Range Wide Area Network (LoRaWAN) has attracted attention because it enables long-distance communication with low power. LoRaWAN adopts the MAC protocol is based on Pure ALOHA and the terminal can send packets at any time. However, the problem is that packet collisions frequently occur as the number of terminals increases. On the other hand, Bluetooth Low Energy (BLE) which is standardized for short-distance communication for IoT is now widely used in various IoT devices because it enables high speed and stable communication. Therefore, we proposed a method that can reduce the traffic on the LoRaWAN by dynamically selecting LoRaWAN and BLE when the terminals move in an environment where it can use both systems. However, it is necessary to consider the Quality of Service (QoS) requirements which are the application requirements of the terminal because LoRaWAN and BLE is standardized supposed different target applications. Therefore, in this paper, we propose a method that can adaptively select a system by weighting the QoS realizations of each system such as the packet error rate predicted using the Spectrum Database and the power consumption during communication with the application requirements of the terminal.

  • APSIPA - Compensation Method of Received Signal Power observed by Smartphone for Crowdsensed Spectrum Database
    2020
    Co-Authors: Taiki Matsushima, Takeo Fujii
    Abstract:

    Crowdsensing is a technique for observing a wide range of radio environments at high density. Collecting radio environment information using sensors built into smartphones, a huge data set can be acquired while reducing the installation cost of new measurement equipment. By accumulating the data set in Measurement-based Spectrum Database (MSD), a wide range and high-precision Radio Environment Map (REM) can be generated. However, crowdsensing is impossible to measure the received power accurately without considering the power fluctuation due to the difference of the working scenario, e.g. specific conditions of human such as putting a wireless terminal in a pocket, and the error tendency of each terminal. In this research, we have a measurement campaign focusing on measurement errors caused by working scenarios and smartphone types in the cellular environment. Also, we propose the compensation method of observed values using simple linear regression. In the proposed method, the observed value of the terminal and one of the measurement equipment for area evaluation for LTE system are compared. Those data are classified in the MSD, and the mesh IDs are obtained. Then, those data matching mesh IDs are plotted to obtain a simple regression line. The predicted value is compensated by substituting the observed value of the terminal into the regression line. Comparing the difference between the ground-truth and the predicted value, the proposed method can improve the accuracy of REM under all working scenarios and smartphone types.

  • Packet Delivery Ratio Prediction for V2V Based on Radio Environment Map Considering Hidden Terminal Problem
    International Journal of Intelligent Transportation Systems Research, 2020
    Co-Authors: Ayumu Ueda, Takeo Fujii
    Abstract:

    Recently, vehicle-to-vehicle communication has been envisaged to be one of the technologies for realizing highly safe connected and automated driving. One of the approaches for predicting the radio environment is the use of a measurement-based Spectrum Database, which stores various pieces of information on the radio environment of data received and collected by vehicles; however, prediction of an accurate packet delivery ratio (PDR) with consideration of packet collisions is difficult if the vehicle density changes after the generation of PDR maps. This paper proposes a method for predicting the PDR with consideration of packet collisions, including the influence of hidden nodes, by using the positions and number of vehicles.

  • VTC-Fall - Interference Management with Beamforming Utilizing Spectrum Database for Micro Operators
    2020 IEEE 92nd Vehicular Technology Conference (VTC2020-Fall), 2020
    Co-Authors: Tetsuki Taniguchi, Takeo Fujii
    Abstract:

    This paper describes interference management utilizing Spectrum Database and beamforming in micro operator based cellular system. For administrating wireless system consisting of small cells operated by micro operators, interference mitigation has an important role for realizing realiable broadband communication under efficient resource allocation. Spectrum Database which stores various information inside of meshes (rectangular small segments which cover entire commu- nicaiton area) is a quite effective tool, and this paper shows how to use data of received signal power for cotroling outage signal to interference plus noise ratio (SINR) in target meshes. Computer simulation shows the effectiveness of the proposed approach, and high potential of Spectrum Database in the context of micro operator based cellular system.

  • ICAIIC - Measurement-based Spectrum Database for Wireless Distributed Networks Using Shadowing Classifier
    2020 International Conference on Artificial Intelligence in Information and Communication (ICAIIC), 2020
    Co-Authors: Keita Katagiri, Takeo Fujii
    Abstract:

    In this paper, we propose a shadowing classifier for the wireless distributed networks (WDNs). In the WDNs, since both transmitters and receivers move, it is difficult to estimate the radio environment accurately due to the dynamic change of surrounding environment. As an accurate estimation method of the radio environment, we had proposed a measurement-based Spectrum Database (MSD) for the WDNs. However, since the MSD stores the statistical data for each transmitter / receiver location, the registered data size is enormous. Therefore, we unify the statistical data in multiple meshes by using the shadowing classifier. In the proposed method, the Database server constructs the $K$ propagation models including the shadowing components by using the measurement datasets. Then, the Database server assigns the modeled shadowing component in each transmission / reception mesh so that root mean square error between the instantaneous RSSIs and the propagation model is minimized. To evaluate the accuracy of the proposed classifier, we use the measurement datasets of vehicle-to-vehicle communications. The evaluation results show that the proposed classifier can accurately estimate the radio environment while the registered data size is significantly reduced.

Sachin Shetty - One of the best experts on this subject based on the ideXlab platform.

  • Resource Allocation in Spectrum Overlay Cognitive Radio Networks
    Dynamic Spectrum Access for Wireless Networks, 2015
    Co-Authors: Danda B. Rawat, Min Song, Sachin Shetty
    Abstract:

    Opportunistic Spectrum access (OSA) is an emerging concept for Spectrum overlay based Spectrum sharing model where SUs identify Spectrum opportunities in licensed bands and use them opportunistically without interfering with PUs [12, 20, 34, 36]. In Spectrum overlay approach, as SUs are not allowed to co-exists with PUs in the same channel, they are required to either sense Spectrum to find idle channels or search for idle channels in Spectrum Database [1, 8, 27]. Spectrum Database can maintain geolocations of idle bands and provide a global view on entire frequencies which could be used to find best suitable channels for the SUs. Based on the global view of wideband RF regime, SUs could be granted a channel that has more adjacent channels so that SUs could implement channel bonding for higher data rates [13]. To prepare and update the Spectrum Database, Database server can get Spectrum occupancy information from PUs’ infrastructure (e.g. base stations or access points) in a real-time basis. Alternatively, Spectrum sensors (e.g., crowd sourcing for sensing [9, 38]) could be deployed to collect information about channel status. Based on the collected information, Spectrum server can process data (with the help of cloud computing platform) to create a Spectrum maps for Spectrum opportunities for different wireless networks such as satellite, WiMAX, Wi-Fi, cellular, TV, etc. Spectrum servers could be associated with a single or multiple Spectrum brokers. When a SU wants to access Spectrum opportunities, it searches the geolocation Database for idle bands. If there is an idle band available in given location and time, SU would access it. Otherwise, the SU has to wait until it finds Spectrum opportunities that meets its needs.

  • WCNC - Cloud-assisted GPS-driven dynamic Spectrum access in cognitive radio vehicular networks for transportation cyber physical systems
    2015 IEEE Wireless Communications and Networking Conference (WCNC), 2015
    Co-Authors: Danda B. Rawat, Swetha Reddy, Nimish Sharma, Bhed Bahadur Bista, Sachin Shetty
    Abstract:

    Transportation Cyber Physical Systems (CPS) are expected to rely on robust wireless communication networks for real-time feedback for controlling these systems. The IEEE 802.11p based Dedicated Short Range Communication (DSRC) standard has been proposed for vehicular communications that has 7 channels. However, these channels could be easily congested resulting in delay and unreliable communications when vehicle density is high. In this paper, we present a cloud-assisted global positioning system (GPS)-driven dynamic Spectrum access framework for transportation CPS. To provide reliable communications, we assume that each vehicle is equipped with two transceivers: one transceiver (always connected to the internet using e.g., 4G link) queries Spectrum Database and/or can serve as a GPS through an application (app), and the other transceiver/radio switches channels and adapts to suitable transmit parameters for vehicular communications to avoid any harmful interference to primary users (PUs). Each vehicle calculates the best route to its destination using GPS and finds the set of idle channels along the route. Furthermore, each vehicle periodically checks the Spectrum Database throughout the route to get most updated Spectrum opportunities. We present performance evaluation of the proposed approach with the help numerical results obtained from simulations.

  • IPCCC - Cloud-assisted dynamic Spectrum access for VANET in transportation cyber-physical systems
    2014 IEEE 33rd International Performance Computing and Communications Conference (IPCCC), 2014
    Co-Authors: Danda B. Rawat, Swetha Reddy, Nimish Sharma, Sachin Shetty
    Abstract:

    Vehicular networking is regarded as a backbone for transportation cyber-physical systems (CPS). In this paper, we propose a cloud-assisted dynamic Spectrum access in vehicular networks where vehicles search the Spectrum Database for idle channels. Each vehicle queries Spectrum Database periodically (every other time/distance unit or so) for a route computed by GPS to find idle channels. When two vehicles are within the communication range, they setup a communication link in a channel and exchange their data with the help of software defined radios. The performance of the proposed approach is evaluated with the help of numerical results obtained from simulations.

Shota Yamashita - One of the best experts on this subject based on the ideXlab platform.

  • Exclusive Region Design for Spatial Grid-Based Spectrum Database: A Stochastic Geometry Approach
    IEEE Access, 2018
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    This paper presents the stochastic-geometry analysis and designs a primary exclusive region (PER) for a spatial grid-based Spectrum Database system. The purpose of the spatial grid is to utilize information, such as the primary receiver (PR) antenna pattern, and the secondary transmitter (ST) density and transmission power, in each divided region. This paper introduces polar and square grids. For these spatial grids, the cumulants of the aggregate interference at a PR, from the STs, are derived, where the probability generating functional for the Poisson point process (PPP) is used on the assumption that the distribution of the STs in each divided region follows an inhomogeneous PPP. In addition, by introducing the allowable transmission probability of STs in each divided region, the PER optimization problem can be formulated as a continuous optimization problem. Numerical results demonstrate that a PER, corresponding to the information, is successfully designed and that more detailed information, due to a reduction in the area of each divided region, leads to a smaller and complex-shaped PER.

  • stochastic geometry analysis of spatial grid based Spectrum Database
    Vehicular Technology Conference, 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) can experience harmful interference due to unexpected propagation paths, even when the secondary user (SU) follows the Spectrum sharing policy stored in a Database, during operations. A framework for deriving the optimal radius of a circular primary exclusive region (PER) has been proposed. However, a practical PER can be non-circular and should be designed on the basis of the geographical information and directivity of the PU antenna. To design a non-circular PER, in this paper, we introduce a spatial grid-based Spectrum Database; the Database permits or forbids SU transmissions for each annular sector divided by a spatial grid. Considering the random locations of the SUs on each annular sector as an inhomogeneous Poisson point process, we analytically derive the PU's outage probability (OP) using stochastic geometry, where the PU's OP is defined as the probability that the aggregate interference power at a PU, from the SUs, exceeds a threshold. Numerical results show that a non- circular PER results in a lower PU OP compared to a circular PER.

  • Optimization of primary exclusive region in spatial grid-based Spectrum Database using stochastic Geometry
    2017 IEEE International Conference on Communications (ICC), 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) may experience harmful interference caused by unpredictable propagation paths, even when secondary users (SUs) follow a Spectrum sharing policy established on the basis of a Database. A framework for determining the optimal radius of a circular primary exclusive region (PER) on the basis of SU's information has been proposed. However, a practical PER can be complex-shaped and should be designed on the basis of the directivity of the PU antenna, and the SU information in each region. In this paper, we present a stochastic geometry analysis in a spatial grid-based Spectrum Database, and propose a design for an optimal complex-shaped PER. The Database determines the transmission probability of the SUs on each divided annular sector. By regarding the SU's locations on each annular sector as an inhomogeneous Poisson point process, we analytically derive a PU's outage probability (OP), where the PU's OP is defined as the probability that the aggregate interference power at a PU from the SUs exceeds a threshold. Using the derived expression, we formulate an optimization problem to maximize the number of transmitting SUs, which optimizes the SU's transmission probability on each annular sector. Then, we numerically evaluate the solution of the optimization problem in various scenarios. The results show that the accuracy of the PER improves as the grid size decreases. In addition, we successfully design a complex-shaped PER with holes in which the SUs are permitted to transmit.

  • VTC Spring - Stochastic Geometry Analysis of Spatial Grid-Based Spectrum Database
    2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) can experience harmful interference due to unexpected propagation paths, even when the secondary user (SU) follows the Spectrum sharing policy stored in a Database, during operations. A framework for deriving the optimal radius of a circular primary exclusive region (PER) has been proposed. However, a practical PER can be non-circular and should be designed on the basis of the geographical information and directivity of the PU antenna. To design a non-circular PER, in this paper, we introduce a spatial grid-based Spectrum Database; the Database permits or forbids SU transmissions for each annular sector divided by a spatial grid. Considering the random locations of the SUs on each annular sector as an inhomogeneous Poisson point process, we analytically derive the PU's outage probability (OP) using stochastic geometry, where the PU's OP is defined as the probability that the aggregate interference power at a PU, from the SUs, exceeds a threshold. Numerical results show that a non- circular PER results in a lower PU OP compared to a circular PER.

  • ICC - Optimization of primary exclusive region in spatial grid-based Spectrum Database using stochastic Geometry
    2017 IEEE International Conference on Communications (ICC), 2017
    Co-Authors: Shota Yamashita, Koji Yamamoto, Takayuki Nishio, Masahiro Morikura
    Abstract:

    In Database-driven Spectrum sharing for 5G mobile networks, a primary user (PU) may experience harmful interference caused by unpredictable propagation paths, even when secondary users (SUs) follow a Spectrum sharing policy established on the basis of a Database. A framework for determining the optimal radius of a circular primary exclusive region (PER) on the basis of SU's information has been proposed. However, a practical PER can be complex-shaped and should be designed on the basis of the directivity of the PU antenna, and the SU information in each region. In this paper, we present a stochastic geometry analysis in a spatial grid-based Spectrum Database, and propose a design for an optimal complex-shaped PER. The Database determines the transmission probability of the SUs on each divided annular sector. By regarding the SU's locations on each annular sector as an inhomogeneous Poisson point process, we analytically derive a PU's outage probability (OP), where the PU's OP is defined as the probability that the aggregate interference power at a PU from the SUs exceeds a threshold. Using the derived expression, we formulate an optimization problem to maximize the number of transmitting SUs, which optimizes the SU's transmission probability on each annular sector. Then, we numerically evaluate the solution of the optimization problem in various scenarios. The results show that the accuracy of the PER improves as the grid size decreases. In addition, we successfully design a complex-shaped PER with holes in which the SUs are permitted to transmit.