GB2522927A - A method and system: back-tracking forward-looking (BTFL) dynamic channel allocation mechanism for white space radio - Google Patents

Abstract

Spectrum is allocated to enquiring white space devices to ensure that no harmful interference occurs with other devices within a white space radio network. An enquiring white space device requests at least one channel or spectrum range from an allocation server. The allocation server determines whether the white space device is operating on a local or national instance. The allocation server communicates with a pre-populated white space database which indicates available unused white space channels, calculated from primary transmitter parameters and having at least local and national instances. The allocation server determines which available channels are applicable to the enquiring white space device based on the pre-defined location and time period. The available channels are classified and ranked into a first list of channels with best single channel characteristics and a second list with best contiguous channel characteristics. The channels are allocated to the enquiring white space devices on a first-come first-served basis.

Description

A method and system: back-tracking forward-looking (BTFL) dynamic channel allocation mechanism for white space radio networks

FIELD OF INVENTION

This invention relates generally to dynamic allocation of channels in the radio frequency (RE) spectrum (esp. unused analogue, digital mobile and fixed terrestrial fixed broadcast TV transmitting channels) and specifically to a method and system for back-tracking forward-looking dynamic channel allocation mechanism for white space radio networks (WSRNs) that are formed by plurality of white space radios (WSR5). Broadly the invention disseminates the best available unused TV spectrum to the WSRs in a particular network according to their specific service demands while ensuring that no harmful interference occurs among white space radios (WSRs) also known as white space devices (WSD), the terms WSR and WSD will be used interchangeably throughout this document.

BACKGROUND OF INVENTION

A portion of the electromagnetic spectrum that is most useful for radio/wireless telecommunications is called radio frequency (RE) spectrum. RE spectrum ranges from 30 -3,000 MHz. Eurthermore, RE spectrum is divided into two distinct parts, namely the very high frequency (VHF) band which ranges from 30 -300 MHz and the ultra-high frequency (UHE) band which ranges from 300 -3,000 MHz. Most of today's common and emerging radio telecommunications services are found in the VHF and UHF; these services include but are not limited to, FM broadcasting, TV broadcasting, Radio Astronomy, Mobile cellular communications, Machine-to-Machine (M2M) communications and Wireless microphones.

However, in the telecommunications industry, RF spectrum is considered to be a scarce natural resource. The aforementioned scarcity is attributable in part to the traditional inefficient methods of RE spectrum management by national regulatory authorities. RF spectrum is being inefficiently statically allocated on the service-by-s service or band-by-band basis. Such inefficient allocations leave swaths of locally unused RF spectrum in geographical and temporal dimensions. This unused RF spectrum is referred to as white space (WS). WS spectrum can be used on a secondary basis to provide useful wireless telecommunications services. However, such usefulness of WS spectrum can only be exploited provided that existing or primary licensed services such as TV broadcasting is not being harmfully interfered with, with secondary users (S Us).

Spectrum regulators around the world have begun to consider introducing regulations to allow dynamic operations of secondary users in the spectrum bands that are primarily allocated for analogue and or, digital mobile and fixed terrestrial TV broadcasting that lies fallow at particular time and space] hereinafter referred to as television white space (TVWS). However, for such regulations to be successful, an intelligent database system is required to steer operations of SUsIWSDs in the TV bands. This is necessary in order to prevent any harmful interference that may be caused to the primary/licensed TV transmitters.

Eormation of a white space radio network (WSRN) in any given time and geographical location requires a plurality of multiple WSDs, these can be fixed, mobile or a combination of both type of WSDs. Usually, such WSDs contend for the available unused RE spectrum resources in the form of WS channels from the geo-location White Space database (WSDB).

Accordingly, it is an object of the method using such white space database (WSDB) to dynamically determine and allocate available unused TV channels based on location and time of an enquiring WSD(s).

Moreover, it is also equally important that when, the available unused channels are allocated to the enquiring WSD(s), no harmful interference occurs among the WSDs.

Additionally such channel allocation should be performed to fulfil specific service demand of the WSDs.

SUMMARY OF INVENTION

Accordingly, the invention provides a computer-implemented method of allocating spectrum (e.g. via a web-service) to an enquiring white space device (WSD) (e.g. based on its specific service demands, like a video application that can enable a telemedicine link between a rural clinic and an urban hospital which will require higher bandwidth (broadband connection), or machine-to-machine (M2M) application services which will require narrower bandwidth) ensuring that no harmful interference occurs among other enquiring or already operating WSDs, the method including: receiving, by a channel allocation server in communication with a white space database (WSDB), a channel allocation request message from the WSD to allocate at least one channel or spectrum range for a pre-defined geo-location and time period to the WSD having defined transmitter parameters; determining whether the WSD is operating on a local instance or national instance; interrogating a pre-populated white space database (WSDB) indicative of protected contours of primary transmitters and a block of available unused channels calculated from primary transmitter parameters and having at least local and national instances; determining which protected contours of primary transmitters and available channels are applicable to the WSD based on the pre-defined geo-location and time period; classifying and ranking the available unused channels into portfolios based on pre-defined criteria into a single scenario or multiple scenarios, such that channels with best single channel characteristics are ranked in grids in a first single channel portfolio (Portfolio A2) and channels with best contiguous channel characteristics are ranked in grids in a first contiguous channel portfolio (Portfolio Al); and applying, by a white spaces analysis engine (e.g. via a web-service using standardised communication means such as the protocol for accessing white space database (PAWS)) dynamically allocates best available unused channels as classified in the aforementioned portfolios to the enquiring WSDs in a first-come first-serve basis.

This allocation may be temporary in nature such that in a pre-determined length of time the WSDs may be required to repeat the enquiring process again.

The primary transmitters may be analogue, digital mobile or fixed terrestrial broadcasting TV transmitters and wireless microphones. The WSD may be a base station, customer-premises equipment (CPE), personal digital assistance (PDA), generic WS radio device, an IP-TV transmitter, or the like (any of these can be fixed or mobile WSDs).

The pre-defined channel allocation criteria may include a linear distance component, a noise floor component, a single channel inquiry component, a multiple channel (contiguous) enquiry component, a frequency component, a channel type component, a plurality of same channel but found from multiple different primary transmitter stations component, a time of channel availability component and a transmitting power component (spectrum mask).

Additionally, the invention includes the cloud-computing instances; If the WSD is stationary or fixed at a particular location, it may be determined that the WSD is operating at a local cloud level or instance. Accordingly, the local cloud instance of the WSDB may be interrogated for available unused channels. If the WSD is mobile and roaming from one locality to another within a country or nationally, it may be determined that the WSD is operating at a national cloud level or instance.

Accordingly, the national cloud instance of the WSDB may be interrogated for available unused channels. The national cloud instance of the WSDB may comprise a plurality of local cloud instances. The WSDB may comprise at least two instances or levels.

s The WSDB may additionally comprise an international cloud instance, which may comprise a plurality of national cloud instances. Thus, The WSDB may comprise three cloud levels or instances. If the WSD is roaming from one country to another, it may be determined that the WSD is operating at an international cloud level.

Accordingly, the international cloud instance of the WSDB may be interrogated for available unused channels.

The method may be repeated iteratively for single or multiple WSDs installed in fixed geographical location or for a single or multiple mobile WSDs. Once a channel has been availed to a first WSD, it will not be available to a second WSD so that the second or multiple WSDs do not interfere, or only interferes minimally, with the first, and so forth.

More specifically, a method and system: back-tracking forward-looking dynamic channel allocation mechanism for white space radio networks: a WSDB has identified a block of available unused available channels Ui4CHs{i2,3,,nth} that may be used by enquiring WSDS[XXYZ,..nth)* from the same or different geographical localities in any of the aforementioned cloud instances. Such channels are only allocated in accordance to the following pre-defined criteria ( spectrum mask1 ckanneL type, itnear d(stance, no Lse fo or P.DC -single channel &nqu&ys, contiguous c.hanneb tnqurv tfrne of avtlability, freqiwny,ptur&ftv of son This allocation mechanism ensures that when a channel is assigned to a WSD in a given locality, any channel in a future block that might conflict (e.g., possibility of causing harmful interference) this current allocation is temporary removed from the block, and that the allocated channel is not in use by other operating WSD within the locality. The channel allocation will follow the following procedure: Contiguous Channel Inquiry: "Portfolio A1" channel allocation grid: 1. If plurality of same channels does not exist: Contiguous channels with longest linear distances from the edge of the protected contour of the primary transmitter to the enquiring WSD; 2. If plurality of same channels does exist: Contiguous channels with shortest linear distances from the edge of the protected contour of the primary transmitter to the enquiring WSD; 3. Contiguous channels with lowest noise floor; 4. Lowest frequency channel; 5. If contiguous channels are adjacent to channels already allocated to other WSDs, a pre-defined minimum channel separation off-set width is required; 6. Contiguous channels with maximum allowed transmitting power; 7. Contiguous channels with maximum time of availability.

Single Channel Inquiry: "Portfolio A2" channel allocation grid: 1. If plurality of same channels does not exist: Channel with longest linear distance from the edge of the protected contour of the primary transmitter to the enquiring WSD; 2. If plurality of same channels does exist: Channel with longest linear distance from the primary transmitter to the enquiring WSD; 3. Channels with lowest noise floor; 4. Lowest frequency channel; 5. If a channel is adjacent to channels already allocated to other WSDs, a pre-defined minimum channel separation off-set width is required; 6. Channels with maximum allowed transmitting power; 7. Channels with maximum time of availability.

Similarly, using the above procedure, channel allocation grids for Portfolio B12, Cl 2, D1,2" and subsequent grids will have inferior characteristics as those in Portfolio A,, 1,2 - s In all cases, the WSDB will allocate such channels to the enquiring WSDs in a first-come-first serve basis. The above procedure is further illustrated in Figure 5 The method may include the prior step of populating the white space database (WSDB) with a block of available unused channels. In such case, the method may include: the WSDB interrogating, by an extraction engine, a geo-location spectrum database (GLSD) to extract primary transmitter parameters and digital terrain elevation data therefrom for each of a plurality of localities; calculating, by a propagation calculation and digital terrain data processing engine, protected contours based on the primary transmitter parameters within which WSDs are not permitted to operate, thereby to avoid or minimise harmful interference with primary transmitters for each locality; such protected contours are determined by calculating signal attenuation of each primary transmitter in a given locality. The calculations are achieved by utilising radio propagation models such as Longley-Rice (L-R), ITU-R P.1546- 4, ITU-R P.1812, HATA, ITWOM. The methodologies utilised for calculating the protected contours of primary transmitters may be Monte-Carlo (M-C) simulation, minimum coupling loss (MCL) or enhanced minimum coupling loss (EMCL); for every calculation of protected contours of primary transmitters, the WSDB may utilise World Geodetic System (WGS-84); for every calculation of protected contours of primary transmitters, the WSDB may utilise digital terrain elevation data such as shuttle radar topographical maps (SRTM-3/4); calculating, by the white spaces analysis engine, available channels based on the protected contours for each locality; and populating, by the white spaces analysis engine a local cloud instance of the white space database (WSDB) indicative of the protected contours and available channels for each locality and a national cloud instance comprising a plurality of the local cloud instances.

The protected contours may be calculated in accordance with the technology type of the transmitter. Depending on the international telecommunication union (ITU) region, the analogue and digital, mobile or fixed terrestrial broadcast TV channels width are 1.5361516/7/8 MHz wide and 125-250 kHz channel width for wireless microphones. Furthermore, TV transmitter-receiver stations can be categorised according to their service types such as full-power TV station sites, low-power TV station sites, gap-filler stations and self-help relay link sites and studio-transmitter-links. The data processing engine may include predefined regulatory protection parameters by which to calculate the protected contours. The protection parameters may dictate protection ratios for channels based on channel type and transmitter technology type.

The GLSD may be spectrum regulator's central database. Various jurisdictions may have different spectrum allocation regulations, but typically there is some form of database or repository of allocated spectrum. It may be a national database for a particular country or region.

The WSDB may also include an international cloud instance. A plurality of national cloud instances may be gathered to constitute an international cloud instance of the WSDB.

The primary transmitter parameters may include one or more of: geo-location of the transmitter (this can be a point, a polygon or a sphere); service type; antenna radiation pattern; site height above mean sea level (AMSL); antenna height above ground (AGL); maximum effective radiated power (ERP); The white spaces analysis engine may be operable to populate the WSDB with a block of information that may consist: 1. a list of available channels together with an indication of the channel type (e.g. co-channel or adjacent); 2. maximum available contiguous channels; 3. corresponding frequencies of each available channel; 4. maximum allowed transmitting power on each of the available channel; 5. maximum duration of availability of each of the channel; 6. a location name (e.g. a province/area combination); 7. cloud locality for each of available channel; 8. geo-location coordinates of available channels; 9. the protected contours and details of their associated transmitters where available channels were found, together with a call sign of each transmitter; and 10. an indication of the type of technology used by the transmitter having available channels. (The type of technology of the transmitters may be either analogue or digital. If digital, it may be digital, fixed or mobile TV.) The WSDB may be interrogated directly by a WSD via a web-service using standardised communication techniques such as a protocol for accessing white space database (PAWS) or by a human user or administrator. The user/administrator may access the WSDB via a web-based graphical user interface (GUI).

The invention extends to a non-transitory computer-readable medium having stored thereon a computer program which, when executed by a computer, causes the computer to implement the method as defined above.

S The invention extends to a system for dynamic allocation of spectrum to white space devices (WSD5) for no harmful interference among themselves (WSDs) and based on their (WSD5) service demands, the system including: a communication arrangement operable to send/receive a dynamic channel allocation request/response to allocate at least one channel or spectrum range for a pre-defined geo-location and time period to the WSD having defined primary transmitter parameters; a pre-populated white space database (WSDB) indicative of primary transmitters protected contours and a block of available unused channels calculated from primary transmitter parameters and having at least local and national cloud instances; and a white spaces analysis engine operable to: determine whether the WSD is operating on a local or national cloud level; classify the available unused channels into one or multiple scenarios, namely Portfolio A12, "Porffolio B12 C, D12" and so forth and so determine which available unused channels are applicable to the WSD based on the pre-defined geo-location and time period;.

The system may include a channel allocation server. The system may include pre-defined interference criteria and scenario. The WSD may be a single antenna radio device or a multi-antenna radio device.

The system may include: an extraction engine operable to interrogate a geo-location spectrum database (GLSD) to extract primary transmitter parameters therefrom for each of a plurality of localities; and a propagation calculation and digital terrain data processing engine operable to: calculate protected contours based on the primary transmitter parameters within which WSD5 are not permitted to operate, thereby to avoid or minimise interference with primary transmitters for each locality; a white spaces analysis engine operable to: calculate available unused channels based on the protected contours for each locality; and populate a local instance of the white space database (WSDB) indicative of the protected contours and available channels for each locality and a national instance comprising a plurality of the local instances.

The system may include the WSDB. The system may include predefined protection parameters by which to calculate the protected contours.

The system may include a user interface module operable to present a user interface to a human administrator via which the administrator may query the WSDB.

The system may include a processor and a computer-readable medium having stored thereon a computer program. The engines (e.g., the white spaces analysis engine, the extraction engine, and/or the propagation calculation and digital terrain data processing engine) may be conceptual modules corresponding to functional tasks performed by the processor. It is to be understood that the processor may be one or more microprocessors, controllers, or any other suitable computing device, resource, hardware, software, or embedded logic. Further, the system is not necessarily consolidated into one device, but may be distributed among a number of devices.

The system may include a cloud-computing architecture identified as Spectrum s Database as a Service (SDaaS). For example, while the WSDB may form an integral part of the system, it may instead be geographically remote from the processor providing the functional engines.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings.

In the drawings: FIGURE 1 shows a schematic view of a system for dynamic allocation of spectrum to white space devices (WSD5) based on the service demand while ensuring no harmful interference among enquiring or already operating WSDs in a particular white space radio network (WSRN), in accordance with the invention; FIGURE 2 shows a schematic view of a channel allocation server forming part of the system of FIGURE 1; FIGURE 3 shows a flow diagram of a method of populating a WSDB, in accordance with the invention; FIGURE 4 shows a flow diagram of a method of dynamic allocation of spectrum to white space devices (WSD5) based on their service demand while ensuring no harmful interference among enquiring or already operating WSDs, in accordance with the invention; FIGURE 5 shows a block of the flow diagram of FIGURE 4 in more detail; and FIGURE 6 shows a schematic representation of a computer within which a set of instructions, for causing the computer to perform any one or more of the methodologies described herein, may be executed.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENT

The following description of the invention is provided as an enabling teaching of the invention. Those skilled in the relevant art will recognise that many changes can be made to the embodiment described, while still attaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances, and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not a limitation thereof.

Referring to FIGURE 1, reference numeral 100 generally indicates a system for allocating spectrum to an enquiring white space device (WSD) 122 within a white space radio network (WSRN) 130 based on the WSDs 120 service demand while ensuring no harmful interference among active WSDs, in accordance with the invention. The system 100 comprises a channel allocation server 102 (which is described in more detail in FIGURE 2). The channel allocation server 102 together with. The WSDB 104 may be hosted in the cloud and networked thereto.

Accordingly, some WSDs 122 (e.g., base stations) may be able to communicate directly with the channel allocation server 102 via the telecommunications network 110. On the other hand, non-base station WSD 122a, 122b may only be able to communicate with the channel allocation server 102 through the base station WSD 122.

The server 102 is in communication with a conventional geo-location spectrum database (GLSD) 106 which is typically hosted by a third party like an official regulatory authority. The server 102 connects to the GLSD via a telecommunications network 110 which may include packet-switched or circuit-switched networks, and public or private networks. The telecommunications network 110 may include, for example, the Internet and/or a cellular network. Regardless of the precise configuration of the telecommunications network 110, it permits communication between the various connected nodes.

A plurality of conventional primary transmitters 120 (only one of which is illustrated) have been allocated a fixed specific spectrum (in the form of radio communications channels) in which they may operate. Conventional primary transmitters 120 may have single radio communications channel or multiple radio communication channels configuration. This fixed spectrum allocation is overseen by the regulatory authority.

In this example, the transmitter 120 is a TV transmitterwith either analogue or digital mobile or fixed transmission technology. The transmitter 120 in this example has multiple radio communications channels configuration with channels: CHa, CHb and CHc. Usually, there will be a multitude of primary transmitters 120 arranged geographically about a whole country or region, but all should be recorded in the GLSD 106. The transmitter 120 is typically a primary or licensed user.

An enquiring white space device (WSD) 122 is a transceiver which is intended to be allocated, and transmit or receive in, a non-interfering communications channel. Such communications channels are not locally used by the primary transmitters 120 at that particular time. The WSD 122 is typically an unlicensed secondary user. The plurality of WSDs 122 forms an integral part of a white space radio network (WSRN) within which no harmful interference must occur among WSDs. As such, the need exists to allocate communications channels to each enquiring WSD 122 dynamically and reliably.

FIGURE 2 shows the channel allocation server 102 and WSDB 104 in more detail.

The server 102 includes a computer processor 200, a computer-readable medium 210 and a communication arrangement 214. The computer-readable medium 210 has stored thereon a computer program 212 to direct the operation of the processor 200, as well as interference criteria 216 and protection parameters 218. The server 102 may be a stand-alone hardware server or a cloud-based system. The server 102 may provide a user application layer (e.g. web client, WSD client), an application server layer, a data layer (e.g. Database server, propagation modelling layer, terrain modelling layer), an operating system layer, and a virtual or hardware layer (e.g. Spectrum Database as a Service (SDaaS) cloud server). Instead, the interference criteria 216 and/or protection parameters 218 may be stored on the WSDB 104.

The processor 200 (under the direction of the computer program 212) has a number of functional engines or modules, namely an extraction engine 202, a propagation calculation and digital terrain data processing engine 204 (further referred to merely as a data processing engine 204), and a white spaces analysis engine 206. In brief, the extraction engine 202 is operable to interrogate the GLSD 106 and extract data therefrom. The data processing engine 204 is operable to calculate protected contours and available channels based on the extracted data (as depicted in Figure 1). The white spaces analysis engine 206 is operable to determine whether or not a channel may be availed to the enquiring WSD 122 based on the WSDB 104. The functionality of these engines 202-206 is further described below.

The WSDB 104 is conceptually divided into three cloud aspects/instances or sub-databases 250-254. A local (or provincial) cloud instance 250 includes of various individual localities, comprising unused TV channel availability, white space radio network (WSRN) details, wireless services provider (WISP) register/licensing, and WSD access criteria. A national cloud instance 252 includes a WSD register, Authentication, Authorization and Accounting (AAA), wireless services provider (WISP) register/licensing, interference criteria, regulatory and policy data. Finally, the international cloud instance 254 includes WSDs roaming data, cross-border or country-to-country interference control regulatory and policy data. Depending on the operating level and roaming status of the WSD 122b, one of the three instances 250- 254 will be applicable.

FIGURE 3 shows a flow diagram of a method 300 of populating WSDB 104, in accordance with the invention. The method 300 is implemented by the server 102 but, in other embodiments, the server 102 could implement a different method or the method 300 could be implemented by a different computing device.

The WSDB 104 may be queried by an enquiring WSD 122 via a web-service using standardised communication means such as the protocol for accessing white space database (PAWS) or by a human administrator using a web-based graphical user interface provided by the server 102 and delivered in an html format.

A WSD 122 is activated and it requires dynamic allocation of a channel to enable itto operate. The WSD 122 sends an electronic channel request message (via the telecommunications network 110) to the channel allocation server 102 which, in turn, receives (at block 502) the request message. The request message also includes a geo-location of the WSD 122 and time period for which the WSD 122 requires the channel, together with transmitter parameters of the WSD 122. The request message may include specific service demands that may require single channel or contiguous channels based on the WSD service demand.

The server 102 determines (at block 503) the operating level of the WSD 122, 122a, 122b e.g., local and stationary, mobile roaming nationally, or mobile roaming internationally. The operating level may be defined in the channel allocation request, or may be deduced from historical access data.

The server 102 interrogates (at block 504) the WSDB 104 in order to retrieve the protected contours and available channel data (as depicted in Figure 1) and the white spaces analysis engine 206 then determines (at block 506) which of the protected contours and available channels are applicable to the WSD 122. The white spaces analysis engine 206 classifies (at block 507) the best available unused channels 122 into one or multiple scenario: "Portfolio A12", "Portfolio B12" and so forth.

By applying (at block 508) the pie-defined criteria 216 and the interference measure such that the allocated channel is not in use by other operating WSD within the locality and that the allocated channel or any other channel that may cause conflict is temporary withdrawn from the block for future use., a channel is either availed to the WSD 122, or not. The best channels are dynamically allocated in accordance with the following procedure: Contiguous Channel Inquiry: "Portfolio A1" channel allocation grid: 1. If plurality of same channels does not exist: Contiguous channels with longest linear distances from the edge of the protected contour of the primary transmitter to the enquiring WSD; 2. If plurality of same channels does exist: Contiguous channels with shortest linear distances from the edge of the protected contour of the primary transmitter to the enquiring WSD; 3. Contiguous channels with lowest noise floor; 4. Lowest frequency channel; 5. If contiguous channels are adjacent to channels already allocated to other WSDs, a predefined minimum channel separation width is required; 6. Contiguous channels with maximum allowed transmitting power; 7. Contiguous channels with maximum time of availability.

Single Channel Inquiry: "Portfolio A2" channel allocation grid: 1. If plurality of same channels does not exist: Channel with longest linear distance from the edge of the protected contour of the primary transmitter to the enquiring WSD; 2. If plurality of same channels does exist: Channel with longest linear distance from the edge of the protected contour of the primary transmitter to the enquiring WSD; 3. Channels with lowest noise floor; 4. Lowest frequency channel; 5. If a channels is adjacent to channels already allocated to other WSDs, a pre-defined minimum channel separation width is required; 6. Channels with maximum allowed transmitting power; 7. Channels with maximum time of availability.

Similarly, using the above procedure, subsequently channel allocation inquiries for "Portfolio B1,2, C12, D12" and subsequent grids will have inferior characteristics as S those in Portfolio A12".

In all cases, the WSDB will dynamically allocate such channels to the enquiring WSDs in a first-come-first serve basis. The above procedure is further illustrated in FIGURES 4-5.

Term Definition PSC Plurality of the Same Channel NPSC No Plurality of the Same Channel NF Noise Floor F Frequency TP Transmitting Power TA Time of Availability Table 1: Definitions of abbreviations used in FIGURE 5 The white spaces analysis engine determines all primary transmitters 120 located within a pre-defined minimum distance of the WSD 122 vicinity which could potentially be interfered to, and the protected contours (such as those depicted in Figure 1) for each of these transmitters 120 is retrieved.

A list of available unused TV channels may then be populated and may be availed to the WSD 122. For channel allocation to plural WSDs, the method is repeated, with any already allocated WSDs taken into account (like the primary transmitters 120) for channel allocation to subsequent enquiring WSDs.

FIGURE 6 shows a diagrammatic representation of a computer 600 within which a set of instructions, for causing the computer 600 to perform any one or more of the methodologies described herein, may be executed. In a networked deployment, the computer 600 may operate in the capacity of a server or a client machine in server-S client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer 600 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a cellular telephone, a web appliance, a network router, switch or bridge, or any computer 600 capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that computer 600. Further, while only a single computer 600 is illustrated, the term "computer" shall also be taken to include any collection of computers that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

The example computer system 600 includes a processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU) or both, a main memory 604 and a static memory 606, which communicate with each other via a bus 608.

The computer 600 may further include a video display unit 610 (e.g., a liquid crystal display (LCD)). The computer 600 also includes an alphanumeric input device 612 (e.g., a keyboard), a graphical user interface (GUI) navigation device 614 (e.g., a mouse), a disk drive unit 616, a signal generation device 618 (e.g., a speaker) and a network interface device 620.

The disk drive unit 616 includes a computer-readable medium 622 on which is stored one or more sets of instructions and data structures (e.g., software 624) embodying or utilized by any one or more of the methodologies or functions described herein.

The software 624 may also reside, completely or at least partially, within the main memory 604 and/or within the processor 602 during execution thereof by the computer system 600, the main memory 604 and the processor 602 also constituting computer-readable media.

-20 -The software 624 may further be transmitted or received over a network 626 via the network interface device 620 utilizing any one of a number of well-known transfer protocols (e.g. HTTP, FTP).

S While the computer-readable medium 622 is shown in an example embodiment to be a single medium, the term "computer-readable medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term "computer-readable medium" shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the computer 600 and that cause the computer 600 to perform any one or more of the methodologies of the present embodiments, or that is capable of storing, encoding or carrying data structures utilized by or associated with such a set of instructions. The term "computer-readable medium" shall accordingly be taken to include, but not be limited to, solid-state memories and optical and magnetic media.

The channel allocation server 102 may include at least some of the components of the computer 600.

The Applicant believes that the invention as exemplified is advantageous in that it provides a method of provisioning vacant channels to secondary WSDs 122 based on their specific service demands as well as without risking interference among themselves. Further, it provides for the creation of a white space database (WSDB) 104 based on presently available information. -21 -

Claims (23)

1. CLAIMSA computer-implemented method of allocating spectrum to an enquiring white space device (WSD), ensuring that no harmful interference occurs among other enquiring or already operating WSDs within a white space radio network (WSRN), the method including: receiving, by a channel allocation server in communication with a white space database (WSDB), a channel allocation request message from the WSD to allocate at least one channel or spectrum range for a pre-defined geo-location and time period to the WSD having defined transmitter parameters; determining whether the WSD is operating on a local instance or national instance; interrogating a pre-populated white space database (WSDB) indicative of protected contours of primary transmitters and a block of available unused channels calculated from primary transmitter parameters and having at least local and national instances; determining which protected contours of the primary transmitters and available channels are applicable to the WSD based on the pre-defined geo-location and time period; classifying and ranking the available unused channels into portfolios based on pre-defined criteria into a single scenario or multiple scenarios, such that channels with best single channel characteristics are ranked in grids in a first single channel portfolio (Portfolio A2) and channels with best contiguous channel characteristics are ranked in grids in a first contiguous channel portfolio (Portfolio Ai); and allocating dynamically, by a white spaces analysis engine, best available unused channels as classified in the aforementioned portfolios to the enquiring WSDs on a first-come first-served basis.

   -22 -
2. 2. The method as claimed in claim 1, in which classifying and ranking further includes defining second and subsequent portfolios, such that channels with second-best single channel characteristics are ranked in grids in a second single channel portfolio (Portfolio B2) and channels with second-best S contiguous channel characteristics are ranked in grids in a second contiguous channel portfolio (Portfolio Bi), and so forth (Portfolios C1, C2...).
3. 3. The method as claimed in any of claims 1-2, in which the allocation is temporary in nature such that after a pre-determined length of time the WSDs are required to repeat the enquiring process.
4. 4. The method as claimed in any of claims 1-3, in which the pre-defined channel allocation criteria includes at least one of a linear distance component, a noise floor component, a single channel inquiry component, a multiple channel (contiguous) enquiry component, a frequency component, a channel type component, a plurality of same channel but found from multiple different primary transmitter stations component, a time of channel availability component and a transmitting power component (spectrum mask).
5. 5. The method as claimed in any of claims 1-4, which is implemented via a web service and in which the local and national instances are local and national cloud instances.
6. 6. The method as claimed in claim 5, in which: it is determined that the WSD is operating at a local cloud instance if the WSD is stationary; and it is determined that the WSD is operating at a national cloud instance if the WSD is roaming from one locality to another within a country or nationally.

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7. 7. The method as claimed in any of claims 5-6, in which the WSDB additionally comprises an international cloud instance, which comprises a plurality of national cloud instances.
8. 8. The method as claimed in claim 7, in which it is determined that the WSD is operating at an international cloud instance if the WSD is roaming from one country to another.
9. 9. The method as claimed in any of claims 1-8, which is repeated iteratively for multiple WSDs or for a single WSD having multiple antennas.
10. 10. The method as claimed in any of claims 1-9, in which the allocating of best available unused channels in respect of the first contiguous channel portfolio (Portfolio Ai) includes the following considerations: If plurality of same channels does not exist: Contiguous channels with longest linear distances from the edge of the protected contour of the primary transmitter to the enquiring WSD; If plurality of same channels does exist: Contiguous channels with shortest linear distances from the edge of the protected contour of the primary transmitter to the enquiring WSD; Contiguous channels with lowest noise floor; Lowest frequency channel; If contiguous channels are adjacent to channels already allocated to other WSDs, a pre-defined minimum channel separation off-set width is required; Contiguous channels with maximum allowed transmitting power; and Contiguous channels with maximum time of availability.

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11. 11. The method as claimed in any of claims 1-10, in which the allocating of best available unused channels in respect of the first single channel portfolio (Portfolio A2) includes the following considerations: If plurality of same channels does not exist: Channel with longest linear distance from the edge of the protected contour of the primary transmitter to the enquiring WSD; If plurality of same channels does exist: Channel with longest linear distance from the edge of the protected contour of the primary transmitter to the enquiring WSD; Channels with lowest noise floor; Lowest frequency channel; If a channel is adjacent to channels already allocated to other WSDs, a pre-defined minimum channel separation off-set width is required; Channels with maximum allowed transmitting power; and Channels with maximum time of availability.
12. 12. The method as claimed in any of claims 1-11, which includes the prior step of populating the white space database (WSDB) with a block of available unused channels.
13. 13. The method as claimed in claim 12, which includes: interrogating, by an extraction engine, a geo-location spectrum database (GLSD) to extract primary transmitter parameters and digital terrain elevation data therefrom for each of a plurality of localities; calculating, by a propagation calculation and digital terrain data processing engine, protected contours based on the primary transmitter parameters within which WSDs are not permitted to operate, thereby to avoid or minimise harmful interference with primary transmitters for each locality; -25 -calculating, by the white spaces analysis engine, available channels based on the protected contours for each locality; and populating, by the white spaces analysis engine a local cloud instance of the white space database (WSDB) indicative of the protected contours and available channels for each locality and a national instance comprising a plurality of the local instances.
14. 14. The method as claimed in claim 13, in which the calculations are achieved by utilising radio propagation models including at least one of Longley-Rice (L-R), ITU-R P.1546-4, ITU-R P.1812, HATA, ITWOM.
15. 15. The method as claimed in claims 13-14, in which calculating the protected contours is done by using one of Monte-Carlo (M-C) simulation, minimum coupling loss (MCL) or enhanced minimum coupling loss (EMCL).
16. 16. The method as claimed in any of claims 13-15, in which the WSDB utilises Digital terrain elevation data to represent the protected contours.
17. 17. The method as claimed in any of claims 13-16, in which the protected contours are calculated in accordance with the technology type of the transmitter.
18. 18. The method as claimed in claim 17, in which the primary transmitter parameters includes one or more of: geo-location of the transmitter; service type; antenna radiation pattern; site height above mean sea level (AMSL); antenna height above ground (AGL); and maximum effective radiated power (ERP).

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19. 19. The method as claimed in any of claims 13-18, in which the white spaces analysis engine is operable to populate the WSDB with a block of information that includes at least one of: a list of available channels together with an indication of the channel type; maximum available contiguous channels; corresponding frequencies of each available channel; maximum allowed transmitting power on each of the available channel; maximum duration of availability of each of the channel; a location name; cloud locality for each of available channel; geo-location coordinates of available channels; the protected contours and details of their associated transmitters where available channels were found, together with a call sign of each transmitter; and an indication of the type of technology used by the transmitter having available channels.
20. 20. The method as claimed in any of claims 1-19, in which the WSDB is operable to be interrogated directly by a WSD via a web-service using standardised communication techniques or by a human user or administrator.
21. 21. A non-transitory computer-readable medium having stored thereon a computer program which, when executed by a computer, causes the computer to implement the method as claimed in any of claims 1-20.

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22. 22. A system for dynamic allocation of spectrum to white space devices (WSDs) while ensuring that no harmful interference is caused to active WSDs within a white space radio network (WSRN), the system including: a communication arrangement operable to send/receive a dynamic channel allocation request/response to allocate at least one channel or spectrum range for a pre-defined geo-location and time period to the WSD having defined primary transmitter parameters; a pre-populated white space database (WSDB) indicative of primary transmitters protected contours and a block of available unused channels calculated from primary transmitter parameters and having at least local and national instances; and a white spaces analysis engine operable to: determine whether the WSD is operating on a local or national instance; classify and rank the available unused channels into portfolios based on pre-defined criteria into a single scenario or multiple scenarios, such that channels with best single channel characteristics are ranked in grids in a first single channel portfolio (Portfolio A2) and channels with best contiguous channel characteristics are ranked in grids in a first contiguous channel portfolio (Portfolio Ai); and allocate dynamically best available unused channels as classified in the aforementioned portfolios to the enquiring WSDs on a first-come first-served basis.
23. 23. The system as claimed in claim 22, which is configured to implement the method as claimed in any of claims 1-20.