Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
  • H04W16/14—Spectrum sharing arrangements between different networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
  • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W28/00—Network traffic management; Network resource management
  • H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
  • H04W72/044—Wireless resource allocation based on the type of the allocated resource
  • H04W72/046—Wireless resource allocation based on the type of the allocated resource the resource being in the space domain, e.g. beams

Definitions

• the teachings herein relate generally to wireless networks and devices operating among such networks and are particularly related to the radio spectrum management with cognitive radio or TV White Spaces principles allowing several different radio systems to share the same bandwidth.
• the teachings particularly relate to the computational geometry describing methods of computer science and solving problems that can be stated in terms of geometry, and how computational geometry can be applied in radio spectrum management.
• radio spectrum refers to the part of the electromagnetic spectrum corresponding frequencies lower than around 300 GHz.
• the radio systems for wireless communication cover various fields like mobile cellular networks, wireless local area networks, computer accessory connectivity with Bluetooth, terrestrial TV broadcasting, FM radio, microwave links, radars, wireless control systems, and aviation and marine communication systems to name a few.
• the standards, legislation and regulation have allocated specific parts of the spectrum for each type of system and for each user or operator of the system.
• IEEE 802.1 1 b WLAN utilizes the frequency range of 2.401 -2.495 GHz
• the primary GSM 900 frequency band covers uplink 890-915 MHz and downlink 935-960 MHz area.
• Computational geometry is an area of computer science, which studies algorithmic solutions for geometric problems.
• the computational geometry is applied on various fields like computer graphics, computer aided design and manufacturing (CAD/CAM), geographic information systems (GIS), and robotics.
• CAD/CAM computer aided design and manufacturing
• GIS geographic information systems
• De Berg et.al. give an introduction to algorithms and data structures used to process geometric information: M. de Berg, M. van Kreveld, M. Overmars and O. Schwarzkopf.
• Computational Geometry Algorithms and Applications. Springer Verlag, 2008.
• Dhillon et.al. describe how to apply computational geometry in a cellular network planning: H. S. Dhillon, R. K. Ganti and J. G. Andrews. A trackable framework for coverage and outage in heterogenous cellular networks.
• radio frequencies are a scarce resource, especially on the part of the spectrum, which has favourable propagation characteristics for the planned application and cost structure. Due to fast increasing demand for wireless communication, there are initiatives to improve the efficiency of radio spectrum use in legislative and regulative bodies.
• UBSTITUTE SHEET (ptute 26) proposals for improving the efficiency of the radio spectrum is cognitive radio.
• Cognitive radio is a generic name for the radio technologies that provide improved spectral efficiency by learning about the surrounding radio environment; and adapting its operation based on that. The most commonly referred means to learn about the radio environment are queries in a frequency database and spectrum sensing.
• One of the early steps towards the cognitive radio is TV White Space technology.
• TV White Space is the unused spectrum on TV broadcasting frequencies in an arbitrary location. TV white spaces are especially created by efficient spectrum utilization of the digital broadcasting.
• the Mitola's PhD thesis and the scientific articles related to them are often considered the ground breaking publications in the area of cognitive radio: J.
• the radio spectrum regulators like Ficora in Finland and FCC in the USA maintain and control the use of radio frequencies. They will keep that role also in the future, but more dynamic allocations and market driven interests based on the cognitive radio and TV White Spaces are reasons that new type of spectrum management technology is needed for radio spectrum management.
• FCC specifies TV White Space radio spectrum database requirements as a part of the Commission's rules provide for operation of low power unlicensed wireless devices in the broadcast television spectrum (TV bands) at locations where that spectrum is unused by licensed services: FCC. Second report and order and memorandum opinion and order; In the matter of Unlicensed operation in the TV broadcast bands; Additional spectrum for unlicensed devices below 900 MHz and in the 3 GHz band, Nov 4, 2008.
• a challenge in the spectrum management databases is that the propagation models can be complex, and as there are many existing transmitters affecting the availability, interference, and field strength at any geographic location, a considerable amount of processor computing in required for each request.
• Pre-processing the field strengths for a grid of points covering the regulatory area like a country can speed up finding a result for a query.
• Pre-processing the field strengths with a given grid size, e.g. 1 km distance is always a compromise between the accuracy (radio microphone interference distances are within tens of meters) and preprocessing time, storage space, and retrieval time, which all grow with the square-law along the decrease in the grid point distance.
• the teachings here disclose a solution, which uses computational geometry to find the solution for the radio spectrum management. As an analogue to the computer graphics formats, the computational geometry approach can be considered to represent a vector graphic format and the traditional grid based approach a bitmap graphic format. Summary
• a method comprising: sending a radio spectrum request, by a radio entity to a spectrum management system; a spectrum management system computing spectrum resource; receiving a computed spectrum resource response at a radio entity; a radio entity transmitting on radio spectrum resource indicated by the response; characterised by the spectrum management system computing spectrum resource on geometrical domain.
• an apparatus comprising: at least one processor; and at least one memory having stored therein machine executable instructions, the at least one memory and stored instructions configured to, with the at least one processor, cause the apparatus to: send a radio spectrum request to a spectrum management system; receive a computed spectrum resource response; transmit on radio spectrum resource indicated by the spectrum resource response; characterised by transform the request from the radio frequency domain to geometrical domain, if policy and protocol define so; transform the response from geometrical domain to radio frequency domain, if policy and protocol define so.
• a third aspect of the present invention provide one or more computer readable media storing computer readable instructions that, when executed, cause an apparatus to: send a radio spectrum request to a spectrum management system; receive a computed spectrum resource response; transmit on radio spectrum resource indicated by the spectrum resource response; characterised by transform the request from radio frequency domain to geometrical domain, if policy and protocol define so; transform the response from geometrical domain to radio frequency domain, if policy and protocol define so.
• a fourth aspect of the present invention provide an apparatus comprising: receive a radio spectrum request from a radio entity; compute a spectrum resource response; send a spectrum resource response to the radio entity; characterised by compute the spectrum resource response on geometrical domain; transform the request from radio frequency domain to geometrical domain, if policy and protocol define so; transform the response from geometrical domain to radio frequency domain, if policy and protocol define so.
• a fifth aspect of the present invention provide a computer readable media storing computer readable instructions that, when executed, cause an apparatus to: receive a radio spectrum request from a radio entity; compute a spectrum resource response; send a spectrum resource response to a radio entity; characterised by compute the spectrum resource response on geometrical domain; transform the request from radio frequency domain to geometrical domain, if policy and protocol define so; transform the response from geometrical domain to radio frequency domain, if policy and protocol define so.
• Drawing 1 is a system architecture showing relevant functional blocks for computational geometry in radio spectrum management according to an embodiment of the invention.
• Drawing 2 is an illustration of a simplified geometric representation of existing transmitters and a new radio entity according to exemplary embodiments of the invention.
• Drawing 3 details specific simplified transformation of overlapping circles to polygons according to exemplary embodiments of the invention.
• Drawing 4 is a graph of computing the interference radius from an arbitrary power level of 85 dB attenuation with a free space propagation model according to exemplary embodiments of the invention.
• Drawing 5 is a flow diagram of sending a request by the radio entity according to an embodiment of the invention.
• Drawing 6 is a flow diagram of receiving a response by the radio entity according to an embodiment of the invention.
• Drawing 7 is a schematic process flow diagram illustrating receiving a request, processing it, and sending a response by the spectrum management entity according to an embodiment of the invention.
• the radio spectrum refers to the part of the electromagnetic spectrum corresponding frequencies lower than around 300 GHz.
• One of the main proposals for improving the efficiency of the radio spectrum is cognitive radio.
• TV (television) White Spaces technology describes how to apply the cognitive radio methodology on TV transmission frequencies, which are below 790 MHz in Europe.
• the cognitive radio changes the radio spectrum management in the way that traditionally one radio communication system or one operator was allocated exclusive spectrum for their use, and in the cognitive radio and TV White Space technology several different communication systems co-exist on the same frequency band. In the TV White Space, the typical case is that a primary user TV broadcaster transmitting with relatively few high power transmitters.
• the frequency planning of the TV broadcasting network is carried out so that the same TV broadcast content is transmitted on different frequencies in different geographic areas.
• the TV broadcast frequencies that are not used on certain areas form the TV White Space.
• the (wireless) radio microphones are being moved from the 790-862 MHz to other frequency ranges, of which one is the TV broadcast frequencies below 790 MHz.
• TV broadcasting is often called as the primary user of the TV broadcast spectrum.
• Radio microphones are the secondary user either as an own user group, or it is on the same level with other TV White Space communication systems.
• this document differentiates only primary users (TV broadcast) and secondary users, which include radio microphones and other TV White Space systems.
• the spectrum management in this document refers the methods, algorithms, protocols and devices that are incorporated in sharing the spectrum with cognitive radio and TV White Space principles.
• the components of the system architecture are spectrum management system (102) and radio entity (101 ). They are connected to each other with a communication link (103).
• the spectrum management system controls the radio spectrum to be used for communication by the radio entity with links (1 13a) and (1 13b).
• the radio entity may be just a radio interface module of a computing or communication device.
• the radio entity is a radio network, like a Long Term Evolution (LTE) network, consisting of a number of end user devices and base stations, access points, and other network elements.
• LTE Long Term Evolution
• the radio entity is a network of an access point (1 12) or base station and the devices (1 1 1 a) and (1 1 1 b) connected to it.
• the spectrum management system (102) consists of knowledge of current use of radio spectrum, which is typically expressed as a list of radio transmitters (123), their location and radio transmission characteristics like antenna height, transmission power, frequency range, and antenna radiation pattern.
• the spectrum management system (102) also has knowledge of geography including borders of the country and other administrational information and geographical features impacting the propagation of radio frequencies like sea, lake, forest, field, topography, urban, sub-urban and countryside, including main buildings and other major obstacles (122).
• the spectrum management system may use also other information like inhabitant densities in decision making.
• the key feature of the spectrum management system is to control where, when and with which radio characteristics the radio entities can use the radio spectrum.
• the transmitter information, geography information, and other allocation information may have been pre- processed and stored (124) so that the requests are processed faster
• the control is built so that the following targets are fulfilled: minimize the interference to the primary users; find and allocate optimally spectrum for the communication of radio entities; minimize the interference between the radio entities; follow the spectrum management policy.
• the spectrum management policy is a set of rules and priorities that are defined by the spectrum regulator.
• the spectrum regulators consist of world-wide decision making organizations like World Radio Congress (WRC), continental bodies like European Union (EU) and federal government of the United States, and country and state decision making organizations. Also standards have an important role in the regulation.
• the regulation is typically divided in political decisions by governments and organizations impacting the legislation, and the authorities of operative regulation of the spectrum management like Ficora in Finland and FCC in the USA.
• the policy defines the targets of these regulative bodies.
• the targets include, e.g.: efficient use of radio spectrum; economic welfare generated from the radio spectrum; existing, agreed, and historical radio permissions; fair sharing between different interest groups; market mechanisms like free competition; military use; authority and emergency communication; regional coverage and service obligations; radio use in neighbouring countries and regions.
• the radio spectrum management problem is described in geometrical domain and applied computational geometry in transforming the background information like transmitter and geography information in geometrical domain and solving the problem in geometrical domain, and transforming the solution to the problem from geometrical domain back to radio frequency and geography domains.
• the radio spectrum request is done with a web browser
• the spectrum management system computes the response in geometrical domain
• the spectrum response received by the web browser is used to configure a radio microphone system.
• the radio spectrum response received by the web browser is used to visualize the radio spectrum situation to the user.
• the radio frequency domain contains the radio characteristics of a radio system including transmitter, receiver and the transmission media.
• the characteristics of a radio transmitter are expressed e.g. as center frequency, channel bandwidth, transmission power, polarity, transmitter and receiver height, and antenna radiation pattern.
• the receiver parameters consist e.g. of channel selectivity, antenna gain, and noise figure.
• the transmission media includes the attenuation and propagation model. Most propagation models take into account geographical features like topography and ground type including urban, sub-urban and countryside, forest, fields, lakes, seas, and rivers.
• the geometrical domain contains geometrical structures, methods and algorithms.
• the following aspects are, for example, geometrical structures and methods: lines, planes, discs, polygons, Voronoi diagrams; 2-dimensional, 3-dimensional geometry and higher dimensions; multiplicative weighted Voronoi diagrams, incrementally weighted Voronoi diagrams; doubly- connected edge list, overlays of subdivisions; union, intersection, and difference, triangulation, partitioning, enclosing, convex hulls; casting geometry, orthogonal range query, range searching; kd-trees, range trees, fractional cascading; point location, trapezoidal map, ray tracing, discrepancy, duality; delaunay triangulation, windowing, priority search trees, segment trees; binary space partitions; robot moving, work space, configuration space, Minkowski sum, translational motion planning, rotations; quadtrees, uniform and non-uniform meshes; visibility graphs, and shortest path.
• the transformation between the radio frequency domain and geometrical domain can take place in various ways.
• An example of transformation from radio frequency domain to geometrical domain in order to estimate the impact of a new radio entity, the most simple way is to transform the transmitter to a point location and a circle representing the interference impact, see drawing 2 (darkened circle numbered as 0).
• the radius of the circle depends e.g. on the agreed interference levels, power level, antenna height, center frequency and bandwidth.
• the co-channel interference can be taken into account with the full interference and for the adjacent channel interference the radius of the circle representing the interference distance can be shortened according to the (lower than co-channel) adjacent channel interference level. Most factors describing the interference level, like polarization can also be taken into account in the size of the circle. Some of the radio characteristics are not circular like directional antenna patters, and for those it is possible to create geometric sectors. The sectors may either describe where the interference is present or they may mask the areas to show that on this area there is no interference or the interference is lower. Such masks can be of any geometric shape. Transmitters may be grouped under the same geometric structure, e.g. an access point or base station and devices connected to it may be represented with one geometric structure.
• the service areas of the existing transmitters are transformed to geometrical domain by drawing them as hexagonal cells (201 ) .. (213), as examples.
• the positions of the transmitters form a grid and the transmission power is constant.
• Small transmitters may be located inside a larger service area, see (204) and (209). With equal transmitters the service areas are equal sized circles. In that special case, the service area limits depend on the distance, and the geometric structure of the service areas can be formed with a geometric structure called Voronoi diagram.
• the transmitters differ from each other.
• a better approximation of the service areas can be obtained with a weighted Voronoi diagram, especially with a multiplicative weighted Voronoi diagram.
• the weights of the Voronoi diagrams are calculated by taking into account the radio frequency domain parameters.
• the Voronoi diagrams work best when a wide area coverage has been planned professionally, like in TV broadcasting networks or in the cellular mobile networks. For hotspots and other individual transmitters, individual polygons, circles, or other geometric forms describe the radio characteristics better.
• the service areas (301 ) .. (304) of the existing transmitters (31 1 ) .. (314) overlap, and the users are expected to be served by the stronger signal source.
• the sides of the polygons, lines between points (331 ) and (332); (332) and (333); (332) and (335); (334) and (335); (335) and (336) represent the lines separating the stronger signal source.
• the transmitter service area forms a polygon, and the sides can be curve linear.
• a method to transform geographical information to geometry is to use doubly-connected edge lists.
• a geographical structure like a map is sub-divided into labeled regions.
• the planar subdivisions are formed by planar embeddings of graphs.
• the graphs have node points called vertices, edges connecting the nodes, and faces that are maximal connected subsets of a plane.
• the doubly-connected edge lists contain records for each face, edge, and vertex of a subdivision. In addition to geometric and topological information, the records may also contain other information, like ground type.
• the radio spectrum management problem is solved in geometrical domain.
• the solution can be found with boolean operations: union, intersection, and difference of the geometric interference area representation of the new radio entity and the geometric representations of the service areas of the existing transmitters and the geometric representation of geographic information.
• the interference area of a new radio entity 200
• the overlapping geometric structures express that the new radio entity would cause co- channel interference in those four regions. Due to that, the new radio entity cannot use the frequencies that are in use in those regions.
• the transformation of the result may contain just analysis if the resources in the request can be allocated or not. More sophisticated interpretation of the results contains information about the region where the requested resource is available and what kind of limitations like power level, time of use, antenna height, or frequency range should be applied. The time to process the request is shortened considerably, if as much as possible has been pre-computed already before the request arrives.
• the pre-processing of the existing transmitters consists mainly about applying the selected radio propagation model to the radio parameters of the transmitter and analyzed together with geographical information to give out the geometric structures for interference and service areas.
• the wide area coverage results may resemble a multiplicative weighted Voronoi diagram.
• Such a geographical structure can be pre-computed for all frequency channels.
• each frequency channel creates an own geometric structure, they can be combined together as a three-dimensional geometric structure.
• An additional (often 3rd) dimension can also be created by varying other parameters like allowed interference level.
• the pre-processing of geographical information creates a Geographical Information System (GIS). Additionally in this application, topography and different types of ground impact the geometric description of the transmitter information.
• GIS Geographical Information System
• topography and different types of ground impact the geometric description of the transmitter information.
• the geometric structures containing both geography transmitter information can be pre-computed. When a spectrum request of a radio entity has been accepted and allocated, the transmitter information is updated with the information of the radio entity spectrum allocation.
• the representation on the geometrical domain is also pre-processed.
• a free space 470 MHz radio signal attenuation curve (401 ) is depicted in decibels as a function of distance.
• a particular example how to compute the radius of the circle is presented in the diagram showing the interference distance based on the free space propagation model and signal attenuation.
• the signal level has a level that is attenuated by the amount shown in the curve as a function of distance from the transmitter.
• the interfered receiver characteristics like channel selectivity, antenna gain, and noise figure, the receiver experiences interference from the transmitter.
• the core of the communication protocol between the radio entity and the spectrum management system consists of two messages: a request of spectrum resources from the radio entity to spectrum management system and a response of spectrum allocation from the spectrum management system to the radio entity.
• a key feature of the protocol is that the request or response of spectrum can be expressed in geometrical domain. As both geometric and radio frequency domain requests and responses are possible, and those may be defined in policy settings, the choice of transformation to and from geometrical domain is included in the flow chart of the protocol implementation, see drawings 5, 6, and 7.
• the communication link between the radio entity and the spectrum management system may be the same as the link for which the spectrum request and response are given. On the other hand, the communication link between the radio entity and spectrum management system may be a different one from the link for which the spectrum allocation was given.
• the radio entity has a spectrum need (501 ).
• the protocol description and the policy define, if the request is sent on the radio frequency domain or on the geometrical domain (502). If the request is sent on the geometrical domain, the radio entity transforms the spectrum demand request from the radio frequency domain to the geometrical domain (503). When the request is in the correct domain, the radio entity sends (504) the request to the spectrum management system.
• the radio entity receives a response from the spectrum management entity 601.
• the protocol description and the policy define, if the response is sent on the radio frequency domain or on the geometrical domain. If the response is sent on the geometrical domain
• the radio entity transforms the spectrum demand response in radio frequency domain
• the radio entity uses the spectrum by transmitting on it (604).
• the spectrum management entity receives a spectrum request from the radio entity (701 ).
• the protocol description and the policy define, if the request is sent on the radio frequency domain or on the geometrical domain (702). If the request is received on the radio frequency domain, the spectrum management entity transforms the spectrum request to the geometrical domain (703). When the request is in the geometrical domain, the spectrum management system checks the availability of the relevant geography and transmitter information (704). If geography and transmitter information does not exist on the geometrical domain (704), the spectrum management system transforms the relevant transmitter and geography information to the geometrical domain (705). When the request, transmitter, and geography information are in the geometrical domain, the spectrum management entity processes the request in the geometrical domain (706).
• the response contains the information that allocation cannot be made (707).
• the protocol description and the policy define, if the response is sent on the radio frequency domain or on the geometrical domain. If the request can be allocated, the transmitter data is updated (710). If the response is sent on the radio frequency domain (708), the spectrum management system transforms the response to the frequency domain (709). When the response is on the correct domain, the spectrum management system sends the response to the radio entity (71 1 ).
• the spectrum management system internal policy defines how much pre-processing is done and at what time. When the pre-processing is required (712), the spectrum management system pre-processes the transmitter data so that the new allocation is also taken into account in the pre-processing.

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  • 2011-05-19 FI FI20110170A patent/FI20110170A/fi not_active Application Discontinuation
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