Patent Application
20120108179
The field of the invention relates to radio coexistence concepts and utilization of RF spectrum to provide for wireless resource sharing between heterogeneous wireless networks to enable coexistence of secondary networks.
Use of radio frequency bands of the electromagnetic spectrum is regulated by governments in most countries, by allocating specific frequency bands to particular types of uses, such as licensed bands for commercial radio and television broadcasting, cellular telephony, maritime radio, police, fire, and public safety radio, GPS, radio astronomy, earth stations for satellite communications, and many other uses. Governments also allocate unlicensed bands, for example, for Wireless Regional Area Network (WRAN) broadband access for rural areas and wireless local area networks (WLAN) and wireless personal area networks (WPAN), such as the industrial, scientific, and medical (ISM) band.
In the United States, the Federal Communications Commission (FCC) regulates use of the radio spectrum, including radio and television broadcasting. Frequencies are allocated according to a bandplan in which guard bands are assigned between the allocated radio bands to avoid interference between adjacent signals. There are also unassigned frequency bands in the spectrum that either have never been used or have become free as a result of changes in technology. The unassigned frequency bands and guard bands are referred to as white spaces.
TV white space may be broadly defined as broadcast television spectrum that is unused by licensed services. There are at least two categories of TV white space: [1] Dedicated TV white space is a portion of the spectrum that the FCC has reallocated to unlicensed use from previously analog broadcast usage, and [2] Locally unused spectrum by licensed TV broadcasters in a geographic area.
[1] Dedicated TV white space: In the United States, the FCC has dedicated approximately 400 MHz of white spaces for unlicensed use that became unused after a federally mandated transformation of analog TV broadcasting to digital TV broadcasting. However, the FCC has prohibited unlicensed use of white spaces from interfering with existing licensed uses, including digital TV stations, low power TV stations, cable TV headends, and sites where low power wireless microphones are used. Various proposals have been made for unlicensed use of the white spaces left by the termination of analog TV, for example rural broadband deployment, auxiliary public safety communications, educational and enterprise video conferencing, personal consumer applications, mesh networks, security applications, municipal broadband access, enhanced local coverage and communications, fixed backhaul, and sensor aggregation for smart grid meter reading.
[2] Locally unused spectrum by licensed TV broadcasters: The FCC has adopted rules to allow unlicensed radio transmitters to operate in the broadcast television spectrum at locations where that spectrum is not being used by licensed broadcasters. The FCC required the use of geolocation to establish the location of the unlicensed transmitter and a database of TV bands use by licensed broadcasters organized by their geographic coverage areas, to enable the unlicensed transmitter to know where local TV band white spaces may be available. The FCC required the use of spectrum sensors in the unlicensed transmitter to detect the presence of the incumbent, primary TV broadcaster's signal in the local TV band white space to enable the unlicensed transmitter to immediately relinquish using the band. A primary user in such a local TV band white space would be an incumbent TV broadcaster licensed to operate in that band, but in those geographic areas where there are no licensed incumbent TV broadcasters in operation, other unlicensed secondary users may make use of that band.
Other RF spectrum white spaces may be locally unused in certain geographic areas, such as the frequency allocations from maritime radio in landlocked areas remote from the sea. A primary user in such a maritime radio band would be a maritime radio licensed to operate in that band, but in those geographic areas where there are no licensed maritime radios in operation, other unlicensed secondary users may make use of that band. Similarly, locally unused RF spectrum white spaces may be present in certain geographic locations, such as the frequency allocations from 2.025 GHz to 2.110 GHz for earth stations to transmit to communications satellites, in areas remote from such earth stations. A primary user in such a satellite earth station radio band would be a satellite earth station licensed to operate in that band, but in those geographic areas where there are no satellite earth stations in operation, other unlicensed secondary users may make use of that band.
Method, apparatus, and computer program product embodiments are disclosed for wireless resource sharing between heterogeneous wireless networks to enable coexistence of secondary networks.
An example embodiment of the invention includes a method, comprising the steps of:
identifying a potential neighboring wireless network to a wireless network based on information exchanged with a network controller serving the potential neighboring wireless network; and
sending a reporting interferer request to the network controller serving the potential neighboring wireless network in response to determining that the potential neighboring wireless network is an interferer network to the wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
sending a discovery request to the network controller serving a potential neighboring wireless network; and
receiving a discovery response from the network controller serving the potential neighboring wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
determining that the potential neighbor is a source interferer network if the discovery response indicates no interference at the potential neighboring wireless network, but interference at the wireless network is indicated as originating from the potential neighboring wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
measuring interference received at the wireless network from the potential neighboring wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
receiving information of exchanged transmission power class and geo-location information of the potential neighboring wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
determining that the potential neighbor is a destination network if the discovery response indicates interference at the potential neighboring wireless network from the wireless network, but interference at the wireless network is not indicated as originating from the potential neighboring wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
receiving information of exchanged transmission power class and geo-location information of the potential neighboring wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
receiving a response to the reporting interferer request; and
receiving one or more interferer reports from the network controller serving the neighboring wireless network if the neighboring wireless network was set as an interference source to the wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
receiving a response to the reporting interferer request; and
sending one or more interferer reports to the network controller serving the neighboring wireless network if the neighboring wireless network was set as the interference destination from the wireless network.
An example embodiment of the invention includes a method, comprising the steps of:
receiving a reporting interferer remove request from the network controller serving the neighboring wireless network; and
removing the neighboring wireless network from a reporting interferer list.
An example embodiment of the invention includes an apparatus, comprising:
at least one processor;
at least one memory including computer program code;
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
identify a potential neighboring wireless network to a wireless network based on information exchanged with a network controller serving the potential neighboring wireless network; and
send a reporting interferer request to the network controller serving the potential neighboring wireless network in response to determining that the potential neighboring wireless network is an interferer network to the wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
send a discovery request to the network controller serving a potential neighboring wireless network; and
receive a discovery response from the network controller serving the potential neighboring wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
determine that the potential neighbor is a source interferer network if the discovery response indicates no interference at the potential neighboring wireless network, but interference at the wireless network is indicated as originating from the potential neighboring wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
measure interference received at the wireless network from the potential neighboring wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receive information of exchanged transmission power class and geo-location information of the potential neighboring wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
determine that the potential neighbor is a destination network if the discovery response indicates interference at the potential neighboring wireless network from the wireless network, but interference at the wireless network is not indicated as originating from the potential neighboring wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receive information of exchanged transmission power class and geo-location information of the potential neighboring wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receive a response to the reporting interferer request; and
receive one or more interferer reports from the network controller serving the neighboring wireless network if the neighboring wireless network was set as an interference source to the wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receive a response to the reporting interferer request; and
send one or more interferer reports to the network controller serving the neighboring wireless network if the neighboring wireless network was set as the interference destination from the wireless network.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receive a reporting interferer remove request from the network controller serving the neighboring wireless network; and
remove the neighboring wireless network from a reporting interferer list.
An example embodiment of the invention includes a computer program product comprising computer executable program code recorded on a computer readable storage medium, to perform the methods set forth above.
An example embodiment of the invention includes a method, comprising the steps of:
receiving a reporting interferer request from a network controller serving a potential neighboring wireless network;
determining whether to accept the reporting interferer request; and
sending a response to the reporting interferer request based on determination.
An example embodiment of the invention includes a method, comprising the steps of:
sending one or more interferer reports to the network controller serving the neighboring wireless network if the neighboring wireless network was set as an interference destination.
An example embodiment of the invention includes a method, comprising the steps of:
receiving one or more interferer reports from the network controller serving the neighboring wireless network if the neighboring wireless network was set as an interference source.
An example embodiment of the invention includes a method, comprising the steps of:
receiving a reporting interferer remove request from the network controller serving the neighboring wireless network; and
removing the neighboring wireless network from a reporting interferer list.
An example embodiment of the invention includes an apparatus, comprising:
at least one processor;
at least one memory including computer program code;
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receiving a reporting interferer request from a network controller serving a potential neighboring wireless network;
determining whether to accept the reporting interferer request; and
sending a response to the reporting interferer request based on determination.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
sending one or more interferer reports to the network controller serving the neighboring wireless network if the neighboring wireless network was set as an interference destination.
An example embodiment of the invention includes an apparatus, comprising:
the at least one memory and the computer program code configured to, with the at least one processor, cause the coexistence manager at least to:
receiving a reporting interferer remove request from the network controller serving the neighboring wireless network; and
removing the neighboring wireless network from a reporting interferer list.
An example embodiment of the invention includes a computer program product comprising computer executable program code recorded on a computer readable storage medium, to perform the methods set forth above.
The embodiments of the invention enable wireless resource sharing between heterogeneous wireless networks to enable coexistence of secondary networks.
In the United States, the FCC has opened up 300 MHz to 400 MHz of white spaces for unlicensed use that became unused after a federally mandated transformation of analog TV broadcasting to digital TV broadcasting. However, the FCC has prohibited unlicensed use of white spaces from interfering with existing licensed uses, including digital TV stations, low power TV stations, cable TV headends, and sites where low power wireless microphones are used. Various proposals have been made for unlicensed use of the white spaces left by the termination of analog TV, for example rural broadband deployment, auxiliary public safety communications, educational and enterprise video conferencing, personal consumer applications, mesh networks, security applications, municipal broadband access, enhanced local coverage and communications, fixed backhaul, and sensor aggregation for smart grid meter reading.
Coexistence standards are currently being developed to enable two or more independently operated wireless networks or devices using any radio technologies adapted for TV white space frequency bands, to access the same TV white space frequency band in the same location without mutual interference. Although the description herein is primarily related to TV white space frequency bands, embodiments of the invention are applicable to any type of white space environment having temporary or long term unused frequencies.
The IEEE 802.19 Working Group is currently defining coexistence rules for heterogeneous secondary networks. An example embodiment of the invention enables coexistence between heterogeneous secondary networks and coexistence between secondary networks and primary networks that are required to be protected. Primary networks and users are incumbent users of the selected frequency band that have a form of priority access to the band. Primary networks include networks operating in FCC licensed bands, such as for commercial radio and television broadcasting. Secondary networks and users are allowed to use the selected band only if there are resources that are not used by the primary users. Secondary networks include any broadband networks operating unlicensed in the TV white spaces (TVWS) and using transmission devices that comply with the FCC requirements for TV Band Devices (TVBDs). Fixed TVBD devices and portable TVBD devices (that are a type of master device) that are capable of initiating networks in TVWS, must include geo-location and query a database to determine allowed channels. For portable TVBD devices that are not capable of initiating a network, they operate under control of master devices. There are specific FCC requirements that apply to this kind of client device, for example, FCC ID verification and control signal reception from the master device. Additionally, the FCC rules allow for sensing-only devices. Those devices need not have access geo-location data or a database, but they must include a spectrum sensing capability to identify TV and wireless microphone signals.
The FCC has adopted rules to allow unlicensed radio transmitters to operate in the broadcast television spectrum at locations where that spectrum is not being used by licensed broadcasters. The FCC required the use of geolocation to establish the location of the unlicensed transmitter and a database of TV bands use by licensed broadcasters organized by their geographic coverage areas, to enable the unlicensed transmitter to know where local TV band white spaces may be available. In the case of sensing-only devices, the FCC required the use of spectrum sensors in the unlicensed transmitter to detect the presence of the incumbent, primary TV broadcaster's signal in the local TV band white space to identify channels free from the incumbents. A primary user in such a local TV band white space would be an incumbent TV broadcaster licensed to operate in that band, but in those geographic areas where there are no licensed incumbent TV broadcasters in operation, other unlicensed secondary users may make use of that band.
Other RF spectrum white spaces may be locally unused in certain geographic areas, such as the frequency allocations from maritime radio in landlocked areas remote from the sea. A primary user in such a maritime radio band would be a maritime radio licensed to operate in that band, but in those geographic areas where there are no licensed maritime radios in operation, other unlicensed secondary users may make use of that band. Similarly, locally unused RF spectrum white spaces may be present in certain geographic locations, such as the frequency allocations from 2.025 GHz to 2.110 GHz for earth stations to transmit to communications satellites, in areas remote from such earth stations. A primary user in such a satellite earth station radio band would be a satellite earth station licensed to operate in that band, but in those geographic areas where there are no satellite earth stations in operation, other unlicensed secondary users may make use of that band.
Although the description herein is primarily related to TV white space frequency bands, embodiments of the invention are applicable to any type of white space environment having temporary or long term unused frequencies.
Active coexistence between secondary networks using the TV band white spaces may require new techniques for fairly sharing the available bandwidth among different heterogeneous secondary networks and accord the required preference for primary users of the band. Such new techniques may require some form of communication between the secondary networks to enable a fair usage of the local spectrum. An example embodiment of the invention provides a means for a coexistence manager of a secondary network that requires additional resources, to evaluate what may be a fair spectrum resource allocation between secondary networks in the same area. Based on the result of the evaluation, the coexistence manager of the requesting secondary network may either enable the secondary network to start using the additional resources or terminate the resource request process without further communication to its neighbors if there is no fair way to get more resources. An example embodiment of the invention provides information for resource evaluation process to define a fair share of resources to each secondary network, taking into account that on an average, each node pair in the secondary network should potentially get the same amount of resources.
An example embodiment of the invention applies coexistence rules to enable heterogeneous secondary networks to share available resources in a fair manner and not cause harmful interference to primary networks. An example embodiment of the invention enables the dynamic allocation in TV white spaces (TVWS), of different networks with different standards in different available channel situations. An example embodiment of the invention determines whether the allocation analysis needs to be applied to all real neighbors.
An example embodiment of the invention is disclosed for independent wireless resource sharing on a fair basis to enable selecting the most suitable coexistence between wireless networks.
An example embodiment of the invention includes a hierarchical resource request process that enables reallocation of radio resources in a coexistence band. When new resources are requested by a network, a search is made for free resources in the coexistence band. If this does not succeed, a check is made for any allocated but unused resources in the coexistence band that have been advertised by neighboring networks in the same network allocation group. If there are insufficient advertised resources, then the allocation of resources in neighboring networks is analyzed and compared with the requesting network's need for network resources. There are two graduated stages to the analysis. In an example light analysis stage, an analysis of the allocation of resources is limited to neighboring networks within the same network allocation group as the requesting networks. In a more extensive analysis stage, all of the neighboring networks are analyzed. In this manner, a more complete resource reallocation may be achieved.
An example embodiment of the invention includes the steps to check if there is a free channel or if there are enough advertised resources. The order of these two steps may be reversed and optionally, either one of these two steps may be skipped.
An example embodiment of the invention includes a resource reallocation that enables heterogeneous and unlicensed spectrum users to agree and negotiate on spectrum use to better coexist with each other.
Depending on the wireless environment state, including whether there have been any major changes in the local area of a wireless network after a previous resource allocation, the network needing more resources may initiate either a light resource request process directed only to the networks in the same network allocation group or a more extensive resource request process directed to all networks within interference range. This selective possibility brings more stability to environment when resource needs are varying.
According to at least one embodiment of the present invention, independent wireless resource sharing is achieved on a fair basis to enable selecting the most suitable coexistence between wireless networks.
Radio resource allocations may be changed when a network sees a clear need for a reallocation from its perspective. Each network has a view of its own and its real neighbors' allocations and environmental state based on spectrum mapping, for example. This information may be one of several factors in performing the radio resource allocation analysis.
Other network topologies may make use of example embodiments of the invention, for example more heterogeneous networks, each of which has an Internet connection that they may use first for neighboring network discovery.
A maritime radio operates in a number of licensed frequency allocations and is a primary user in the maritime radio band 33. If there were no licensed maritime radios in operation that would interfere with the WLAN access point STA1 or client device STA2, then they could operate as unlicensed secondary users and make use of maritime radio band 33. If either STA1 or STA2 were to detect a signal transmitted from a neighboring maritime radio, then they would have to relinquish their use of the maritime band 33 and make a resource request, in accordance with example embodiments of the invention.
A satellite earth station transmits to satellites in licensed frequency allocations from 2.025 GHz to 2.110 GHz and is a primary user in the earth-to-satellite band 35. If there were no licensed earth station radios in operation that would interfere with the WLAN access point STA1 or client device STA2, then they could operate as unlicensed secondary users and make use of earth-to-satellite radio band 35. If either STA1 or STA2 were to detect a signal transmitted from a neighboring earth station radio, then they would have to relinquish their use of the earth-to-satellite band 35 and make a resource request, in accordance with example embodiments of the invention.
The key functions of Coexistence Enabler (CE) are to obtain information required for the coexistence from the TV band device (TVBD), and to reconfigure TVBD operation according the coexistence decisions which are received from the Coexistence Manager (CM). The collected information covers the capabilities and the resource need of the TVBD network, and the characteristics of the radio environment. The CE resides in a TVBD, e.g. in an access point, base station, or mesh point.
Coexistence Manager is the main decision maker of the coexistence system. It discovers and solves the coexistence conflicts of the networks operating in the same area. A CM serves one or more networks. Depending on the deployment it resides either in a TVBD or in the network entity. In independent networks it may reside in a TVBD. The CM discovers the interfering networks and their CMs, and shares information with other CMs. Based on the collected information it reconfigures the operation of own network/s, but also performs resource reallocation for the whole neighborhood as needed.
The coexistence system includes a network of coexistence managers (CM), each of which serves one or more coexistence enablers (CE). The coexistence enabler is responsible for obtaining information required for the coexistence of the TV band device (TVBD) and for reconfiguring TVBD operation according the coexistence decisions that are received from the Coexistence Manager (CM).
The coexistence system, i.e., the network of coexistence managers, primary database, and CDIS, has two services to provide: the coexistence management service and the coexistence information service. A master TVBD device may register with either of the services. The coexistence system determines resource usage for those master TVBD devices and their networks that are registered with the coexistence management service. Alternately, the master TVBD device that has registered with the information service, only makes the decisions on resource usage by itself. A master TVBD device is registered through its control node or coexistence enabler CE to coexistence information services associated with its network controller or coexistence manager CM.
Although a master TVBD device may be registered through its control node or coexistence enabler CE to its network controller or coexistence manager CM, embodiments of the invention allow any kind of device, including client devices, to be registered through a control node or CE to a network controller or CM for coexistence management and information system services.
Coexistence Discovery and Information Server (CDIS) assists the CMs in the neighbor discovery. It keeps a record of the registered CMs and location of the networks they serve, and provides a list of candidate neighbors for a CM which initiates the neighbor discovery for its network. CDIS may store also some other information relevant for coexistence, e.g. statistics of the spectrum use.
If there has been a major change in the network neighborhood after a previous resource allocation, resulting in there being not enough free or advertized resources are available to satisfy the requirements of Network “B”, the coexistence enabler 100 and coexistence manager 102 may initiate a resource reallocation process. The resource reallocation process may be either a light resource request process directed only to the networks in the same network allocation group or a more extensive resource request process directed to all networks within interference range. This graduated analysis brings more stability to the network environment when resource needs are varying. Example steps in requesting a reallocation of resources are:
Examples of a network allocation group include self-coexistence scenarios where two systems (a base station or access point and the associated mobile station or STA) use the same technology and may share a frequency channel. For example, an IEEE 802.11 WLAN may coexist with another IEEE 802.11 WLAN in sharing a TV band white space, if both systems use the same physical layer (PHY) technology and channel width. In another example, an IEEE 802.16h WMAN coexists with another IEEE 802.16h WMAN in sharing a TV band white space.
Other examples of a network allocation group include different IEEE 802 network technologies that may be time division multiplexed based on the IEEE 802.16h draft standard and are synchronized with a GPS clock or IEEE 1588 or IETF network time protocol clocks.
Neighboring networks may be identified to a local network, for example, by a coexistence manager transmitting a request to a server via an Internet connection. This request may inquire as to whether other networks are located proximate to the local network in an operational environment. The server may return information to the coexistence manager via the Internet informing the coexistence manager of the proximately-located networks.
The information provided by the server to the coexistence manager may comprise Internet addresses corresponding to potential coexistence enablers or coexistence managers that are managing wireless networks in the same operational environment as the local network. The coexistence manager uses these addresses to contact at least some of the coexistence managers of the potential networks via the Internet in order to request communication configuration and test information. The other networks may respond to these requests, and the coexistence manager may use the communication received configuration and test information to select a group of candidate networks. Candidate networks may be selected based on, for example, the distance from the local network to a potential network, transmission properties (e.g., transmission power of potential networks), etc. Information needed for candidate selection may be provided by potential networks to the local network or the coexistence manager via an Internet connection.
The local network may then initiate testing the group of candidate networks. Testing may comprise transmitting one or more wireless signals that should be receivable by the candidate networks. The coexistence manager may utilize testing results to select real neighbor networks from the group of candidate networks.
In an example embodiment of the invention,
The example system architecture of
The example system architecture of
Although the description herein is primarily related to TV white space frequency bands, embodiments of the invention are applicable to any type of white space environment having temporary or long term unused frequencies.
Control node according to an embodiment of the present invention, such as the CE 100 obtains information required for coexistence from TV Band Device (TVBD) network or device. This includes configuration and control of measurements performed by TVBD network or device. The CE forwards the collected information to its associated network controller, such as CM 102. The information may be formatted in standard format. Also, the CE provides reconfiguration commands and control information to TVBD network or device, corresponding to coexisting decisions received from the associated CM. The CE may reside in a TVBD device, e.g. in access point, base station, or mesh point. There is one CE in a network. It may collect the information from the other network nodes using radio standard specific means.
A network controller, such as the CM 102 is responsible for making the decisions on the spectrum resource sharing, discovery of other CMs controlling neighboring networks and coexistence related information exchange with them. The CM may serve one or more networks. It collects information from associated networks and configures it via a control node of a wireless network, such as CE 100. The CM may also obtain information from the TVWS database. From the collected information the CM constructs the spectrum map for the network, and calculates the amount of resources for which the network is eligible in the current spectrum environment. The information is used in spectrum allocation. The CM commands its CE(s) 100 based on the decisions it and its neighboring CMs have made. It is optional whether there is a hierarchy between CMs. The CM may reside in a TVBD device, or in the network.
The Coexistence Discovery and Information Server (CDIS) 107 assists the CMs 102 to discover possible coexistence conflicts of the networks it controls, and to discover the CMs with which the conflicts may be solved. The CDIS supports the discovery of CMs by keeping a record of the existing CMs and location of the networks they control. It provides a list of potential neighboring CMs for the CMs controlling new or moving networks. Such CDIS server is needed for discovering neighboring networks, because all the networks are not expected to support the same radio connectivity and thus cannot discover each other directly over the radio interface. The CDIS may have other functions like storing more information of each CM, statistics of the spectrum use, or providing common Quiet Period for spectrum sensing. The CDIS may also use the information of primary users due to an optional interface to TVWS database. The CDIS 107 may reside in a TVBD device, or in the network.
The interface circuits in
The interface circuits in
In an example embodiment of the invention, in a first process the Coexistence Enabler (CE) 100 calculates the CoexistenceValue (CV) from some parameters of the network under it, for example the IEEE 802.11 WLAN NETWORK “B”. The CE 100 will transmit a CV value to its CM 102, which will further share it with other CMs of all neighboring networks. In an example embodiment of the invention, in a second process, the CE 100 will transmit its network capabilities to its CM 102, which will share them with the same other CMs of all neighboring networks. In an example embodiment of the invention, in a third process, the spectrum map creation process is performed by the CM 102 from the information received from the CE 100, the primary database 104 and information from the CMs of neighboring networks. The information of these three processes is used when the CE 100 identifies an excess resource need in its network and sends a resource request (RR) containing the amount of additional resources it needs to its CM 102. Each CM 102 has received the CV, the spectrum map and the network capabilities of its own network under CE 100 and neighboring networks. The CM 102 processes the RR, and if an allocation analysis is needed, it uses the CVs of the requesting network and its neighboring networks to evaluate whether the requesting network needing more resources is eligible to for the amount of resources requested in the RR. If the network is eligible to the requested additional resources, its CM 102 will then communicate a new resources allocation to the other CMs of its neighboring networks, or else the CM 102 will inform CE 100 that the network requesting the additional resources is not eligible for the requested resources.
In an example embodiment of the invention, certain parameters provide a good and/or practical representation of the eligibility level to the spectrum resources. The CoexistenceValue (CV) has to be counted with similar methods for each network. Some candidate parameters for the CoexistenceValue include: the number of nodes per network (with particular counting method), the current allocation usage level, and the network capabilities. A particular parameter priority may be used for “tuning the eligibility” among the networks under one CM.
For example, the 802.11 WLAN standards specify an OFDM-based physical layer with a bandwidth of 20 MHz channel separation. At 11 MHz from the center of the channel, the energy is approximately 20 dB lower than the maximum signal level. Further away from the centre frequency, the energy levels fall further resulting in minimal interference on adjacent channels. The TV band white spaces at 54-88 MHz and at 470-806 MHz are good candidates for coexistence of an 802.11 WLAN wireless LAN channel. The earth station-to-satellite white space band at 2.025 GHz to 2.110 GHz is a good candidate for coexistence of an 802.11 WLAN wireless LAN channel. A TV band white space locally unused by licensed TV broadcasters, for example, in the 174-204 MHz band, representing the local absence of broadcast TV channels 7, 8, 9, 10, and 11, as is the circumstance in the Richmond, Va. (USA) area, is a good candidate for coexistence of an 802.11 WLAN wireless LAN channel.
There are a number of TVWS coexistence techniques possible for enabling two or more independently operated wireless networks or devices using different radio technologies adapted for TV white space frequency bands, to access the same TV white space frequency band in the same location without mutual interference. Some examples of coexistence techniques include dynamic frequency selection, transmit power control, listen-before-talk behavior, time division multiplexing different IEEE 802 technologies, message-based on-demand spectrum contention, and control through a centralized network controller or coexistence manager.
The example coexistence technique illustrated here for each sub-band 12, 14, and 16, is time division multiplexing of the slots in TDMA coexistence frames allocated to different IEEE 802 technologies. The two IEEE 802 technologies chosen for this example are the IEEE 802.16h WMAN standard and the IEEE 802.11 WLAN standard. The IEEE 802.16h WMAN uses a fixed outdoor base station, such as the WMAN base station 8, serving indoor and outdoor portable clients, such as the WMAN STA 6. The IEEE 802.11 WLAN station, such as the WLAN access point STA1, may include Internet access and geo-location capability. The TDMA coexistence frame may be divided into a IEEE 802.11 master slot network allocation group and an IEEE 802.16h master slot network allocation group. The IEEE 802.11 master slot network allocation group carries twelve free IEEE 802.11 WLAN white space slots. The IEEE 802.16h master slot network allocation group carries the twelve free IEEE 802.16h WMAN white space slots.
For the control node or coexistence enabler (CE):
CV process: Determine a parameter that characterizes the network's eligibility level to the spectrum resources. The parameter is determined from certain parameters of the network. The parameter may be called a coexistence value (CV). Provide the CV of the network to the CM serving the CE.
RR process: Form a resource request (RR) and issue it to the serving CM. Formed based upon information gathered from the network on its resource needs.
Management process: Registers the CE to a CM in order to become served by the CM. Maintains connection to the CM and provides information e.g. about network capabilities and CE features. Contains support functions that make the actual coexistence management functionality possible.
For the network controller or coexistence manager (CM):
Resource allocation process: Shares CVs from the CEs one is serving with the CMs of the neighboring networks. Exchanges spectrum maps with the CMs of the neighboring networks. Determines resource allocations as described in high level in NC72135 using the CVs and spectrum maps.
Neighbor management: Determines neighbors for the CEs/networks the CM serves (e.g. as per the NC71605) and facilitates connection setup between CMs serving neighboring networks.
CM-to-CM communication: Provides basic communication services for other functions/processes of the CM to exchange information with other CMs. Communication is needed between CMs that serve CEs of neighboring networks to exchange e.g. CV parameter values and RR process related information.
Procedures to find real neighbors, how to analyze fair resource allocation between the real neighbors, and what content is to be communicated between real neighbors is described in the copending U.S. patent application Ser. No. 12/689,663. filed Jan. 19, 2010, entitled “Apparatus Identification In Coexistence Networking”, by Mika Kasslin, Jari Junell, Juha Salokannel, assigned to Nokia Corporation and incorporated herein by reference.
The identification of neighboring networks may be performed by transmitting a request to a server, such as via an Internet connection, to inquire as to whether other networks are located near enough to the requesting network to be in an operational environment. The server may return information to the requesting network via the Internet identifying other proximately-located or potentially interfering networks. The server may inform only about the networks it estimates are most proximate or most interfering with the requesting network. A list of the networks the server provides, may be set in an order based on the distance or estimated amount of interference with the requesting network. The requesting network may utilize this information to communicate with the proximate networks.
In at least one example embodiment, the information provided by the server may include Internet addresses corresponding to network devices in potential neighboring or interfering wireless networks in the same operational environment as the requesting network. The requesting network may contact at least some of the potential neighboring networks via the Internet in order to request communication configuration and test information. The other potential networks may respond to these requests, and the requesting network may use the received configuration and test information to select a group of candidate neighboring networks. Candidate neighboring networks may be selected based on, for example, the distance from the requesting network to a potential neighboring network, transmission properties (for example, transmission power of potential neighboring networks), etc. Information needed for candidate selection may be provided by potential neighboring networks to the requesting network via an Internet connection.
In accordance with at least one example embodiment, the requesting network may then initiate testing the group of candidate neighboring networks. Testing may comprise transmitting one or more wireless signals that should be receivable by the candidate neighboring networks. The candidate neighboring networks that receive the wireless signals may then transmit reports to the requesting network via an Internet connection confirming receipt of a signal. The requesting network may utilize testing results to select real neighbor networks from the group of candidate neighboring networks.
Although the description herein is primarily related to TV white space frequency bands, embodiments of the invention are applicable to any type of white space environment having temporary or long term unused frequencies.
The coexistence manager 102 applies rules in making its determination of which of two networks based on different technologies, should be given priority in spectrum reallocation. For example, WLAN devices are typically designed for better resistance to saturation than WMAN devices, since WMAN devices must be more sensitive to attenuated signals received over a greater range than are WLAN devices. Thus, in an example embodiment of the invention, the coexistence manager 102 will generally favor the reallocation of an 802.11 network to the TVWS band, instead of reallocating the 802.16 network, when spectrum reallocation is requested, so as to remove the source of disturbance from the vicinity of 802.16 network.
The coexistence manager (CM) 102 decides, if no free channel or enough advertized resources were available, whether to grant the request by determining whether resource allocation requires an extensive reallocation or a light reallocation of a number of secondary channels or networks. In a light resource request process, for example, a change in the number of terminals within a single frequency channel may require changes only among the allocations between the users of that channel. In an extensive resource request process, for example, if a primary user reserves a channel, then all secondary users of that channel need to be reallocated to other channels, and a more complete resource reallocation may be initiated.
The coexistence manager 102 then sends to the coexistence enabler 100 in device STA1 the resource reallocation, including Operational parameters, Quiet period parameters, Spectrum sensing strategy, and Time base sync. The coexistence enabler 100 in device STA1 then controls the TV white space MAC to communicate in channels in the TV white spaces band reallocated by the coexistence manager 102, without interference from other networks sharing the same white space channels.
An example embodiment of the types of information exchanged between the coexistence manager 102, primary database 104, Coexistence Discovery & Info Server (CDIS) 107, and control node or coexistence enabler 100 may be as follows.
Between coexistence manager and Primary database:
Between coexistence manager and Coexistence Discovery & Info Server (CDIS):
Processing in coexistence manager:
Between coexistence manager and coexistence enabler:
Procedures to find real neighbors, how to analyze fair resource allocation between the real neighbors, and what content is to be communicated between real neighbors is described in the copending U.S. patent application Ser. No. 12/689,663. filed Jan. 19, 2010, entitled “Apparatus Identification In Coexistence Networking”, by Mika Kasslin, Jari Junell, Juha Salokannel, assigned to Nokia Corporation and incorporated herein by reference.
A scenario where two networks interfere with each other is presented
Note that the networks may not operate in the same channels, and thus may not interfere with each other. However, they may end up operating in the same channel as a result of resource reallocation. That may occur for example if a primary operation has been detected in a channel, a new secondary network appears, or an existing network needs more resources. For efficient resource use, all the interference sources which interfere with or would interfere with the network if they were in the same channel, should be taken into account in resource allocation. If interference sources are not taken into account, the network/s may not end up using the resources more optimally after the resource allocation, because a new allocation to the network may be in channel/slots where also interference source operates. An interference source is a network that interferes with or would interfere with another network if they were in the same channel.
An embodiment of the invention enhances discovery of the operational changes (e.g. utilization, transmission intervals, or channel change) of an interference source (Network1 in above examples) in “one-directional interference” case.
Techniques to discover the interference in white spaces for bidirectional interference include:
An embodiment of the invention enhances the detection of operational changes in an interference source (Network1 in above examples) in the “one-directional interference” case. Here it is assumed that both networks are secondary users of TV white spaces. However, the solution may not be limited to TV white spaces, and secondary networks.
In the one-directional interference case, when allocating resources to a network, information of interference source characteristics may be taken into account to ensure optimal resources for the destination network. If the changes of the interference are received directly from the interference source, the interference destination needs to expend less effort to discover the interference. When allocating resources to interference source, the characteristics of the interference destination do not need to be taken into account, because the destination network does not interfere with the source. This enables easier resource allocation because fewer networks are included in resource allocation.
An embodiment of the invention includes:
A Reporting Interferer Source is a network/node that operation changes are reported to its Reporting Interferer Destination. A Reporting Interferer Destination is a network/node that receives reports of the operation changes of the Reporting Interferer Source.
The coexistence manager (CM) provides coexistence services to the networks and makes decisions on the resources use in the area. A CM may serve one or more Coexistence Enablers (CE) associated to radio networks. When a CM discovers changes in the spectrum availability or spectrum resources need, it calculates the resources to the networks it serves but also their neighbor networks which operate in the same coverage area. Because CM is able to perform resource reallocation, it has to know the interference situation. CM collects information for decision making from Coexistence Discovery and Information server (CDIS), which facilitates in neighbor discovery, from neighbor CMs, and from CEs of the radio networks the CM serves. CEs provide measurements information of channel measurements information.
In embodiments of the invention, even if the network itself makes decisions on the measuring and resource use, obtaining some information directly from the interferer source helps in forming the view of the radio environment and its changes.
1 Setting Networks as Reporting Interferer Source and Destination:
After a CM1 has received a list of candidate neighbors from the CDIS, for a network associated to a CE it serves, it may connect directly to the CMs of the candidate neighbor networks to discover more information of them. This is presented in
CM1 sets remote network set as Reporting Interferer Source, presented in
If the CM2 has indicated that the network of CM1 does not cause interference (Src_to_Dst_Interference=FALSE), but the CM1 has evaluated that the network of CM2 causes interference, the CM1 sends CM_Reporting_Interferer_Set_req to CM2. The request includes indication of the interference evaluated at requesting CM1 (Dst_to_Src_I=TRUE). CM2 sends message CM_Reporting_Interferer_Set_rsp. CM2 may accept or reject the request. If it accepts the request, CM2 adds the network of CM1 as Reporting Interference Destination to its network, and CM1 adds the network of CM2 as Reporting Interference Source to its network.
CM1 sets remote network as Reporting Interferer Destination, presented in
If the CM2 has indicated that the network of CM1 causes interference (Src_to_Dst_Interference=TRUE), but the CM1 has evaluated that the network of CM2 does not cause interference, the CM1 may send message CM_Reporting_Interferer_Set_req to CM2. The request includes indication of the interference evaluated at requesting CM1 (Dst_to_Src_I=FALSE). CM2 sends message CM_Reporting_Interferer_Set_rsp. CM2 may accept or reject the request. If it accepts the request, CM2 adds the network of CM1 as Reporting Interference Source to its network, and CM1 adds the network of CM2 as Reporting Interference Destination to its network.
Once the networks are set as Reporting Interference Destination and Source, the CM of Reporting Interference Source may start sending information of it operational changes to the CM of Reporting Interference Destination, as presented in
Similar discovery, evaluation, and information sharing occurs also when both the networks are managed by the same CM. However, then the signaling is CM internal operation.
2 Removal of Reporting Interference Source or Destination:
Once the either CM discovers that the Reporting Interference Source no longer interferes with the Reporting Interference Destination, or for some other reason does not want to send or receive the Interference reports anymore, the CM sends a CM_Reporting_Interferer_Remove_req to the peer CM, as shown in
3 Evaluating Whether Remote Network Interferes
If the CE is not able to provide measurements, e.g. is not always able to measure the channel where the potential interference resides, the CM may only use the information received from the CM_Interferer_Report to determine whether the Reporting Interferer Source still interferes, and how it affects to the spectrum map and to resource allocations of the network.
Configuring Measurements
CE may configure TVBD device/network to perform measurements. It depends on the CE and device implementation and TVBD radio system how well CE can configure the measurements performed by the network. If CE is able to configure the measurements it responds with CE_Configure_Measurement_rsp[accept], otherwise CE_Configure_Measurement_rsp[reject]. Once the measurement has been performed, CE transmits the result to CM in CE_Measurement_Update. It contains measurement results for each measured channel (Channel State Values, CSVs), including e.g. RSSI levels and activity intervals, other characteristics of the measured interference, and possibly also interference source. Network may be able to identify the interference source well, e.g. if the interference is generated by the same type of radio system as the measuring system. In that case the CE may be able to provide even interference source's network ID, address etc.
The CM uses the measurement results to evaluate whether the candidate neighbor interferes the network.
The CM may also request network to provide measurement results regularly, or as triggered, e.g. when a change in the channel is discovered. This measurement type may be used to continuously evaluate whether a Neighbor or Reporting Interferer source or some other interference is still interfering the network. This measurement may be more relevant for evaluating channels/interference from which there is no other information available, e.g. the interference source is not neighbor or reporting interferer. In that case this measurement type may be used to trigger when interference has been detected on a channel which used to be free, or whether the interference situation has changed. To request/suggest such “continuous” measurements, CM sends CE_Subscribe_Measurement_req to the CE. It may contain similar configuration parameters as CE_Configure_Measurement_req e.g. channel where measurements should be performed, interval, but also the trigger to provide the results to the CM, e.g. when the RSSI exceeds level X, after a time interval, after X packet errors. CE responds with CE_Subsribe_Measurement_rsp[accept] if it is able to perform the measurements to the CM.
If the CM wants to update the measurement subscription, e.g. a neighbor/reporting interferer source has changed the channel, as shown in
4 Interferer Report and its Communication
Interferer report is sent from the CM of Reporting Interferer source to the CM of Reporting Interference Destination to indicate the changes in the operation change of the Source network. Such change may be e.g. channel switch, change of operating bandwidth, change in operation interval or utilization, change in transmission power, and the stability/satisfaction level. CM of the Reporting Interferer Source sends the change information in CM_Interferer_Report to the CMs of Reporting Interferer Destinations. This is presented in
After the CM of the Reporting Interferer Destination has received the message, it may reconfigure the measurements provided by the CE to better align with the changed operation parameters of the Reporting Interferer Source. The reconfiguration is done by sending CE_Subsribe_Measurement_Req to the CE. (Similar reconfiguration takes place also when CM of a neighbor indicates changes in neighbor network operation or after a resource allocation). The CM continues to evaluate whether the Reporting Interferer Source still interferes the network. After receiving the CM_Interferer_Report, and evaluating whether the Reporting Interferer Source still interferes the network, the CM also updates the Spectrum map of the network and shares it with the CMs of the neighbor networks.
5 Using the Information Received from Interferer Report
CM of the Reporting Interferer Destination uses the information of operational parameters of Reporting Interferer Source:
Depending on the information in Reporting Interferer Source, the CM may reconfigure the measurements requested from the network, e.g. the measurement channel, and interval to validate that the Reporting Interferer Source interferes with the network. Such validation may not be always needed, e.g. if the Interferer Report indicates such change that does not decrease the interference (e.g. increase in transmit power, minor channel change). But even if the measurements are performed for validation, the CM may decrease the amount of measurements because it may conclude characteristics of the interference from the Interferer Report.
When creating the Spectrum map for the network, the CM sets the Reporting Interferer Source parameters as limitations to the network. Also in spectrum map the CM may accurately state the limitations if it has received the parameters from the Source. The Spectrum map may include information of how the limitations have been discovered:
If spectrum map indicates that the interference is discovered by measurements only, it typically refers to a network which does not support coexistence.
Compared to situation that the interfering network operation characteristics is only detected by sensing, an embodiment of the invention enables more reliable and accurate discovery of interference caused by the interfering network. The interfered with network can be faster and more quickly take into account the resource use and allocation. Also it may be able to decrease the sensing efforts for trying to discover secondary user operations. Thus an embodiment of the invention improves the performance and efficiency of the interfered with network. It may also improve the performance of the interfering network, e.g. if the interfering network (reporting interferer source) has a wider range and some of its terminals are actually interfered with by the shorter range reporting interferer destination.
Compared to the situation that all the networks within interference range would be set as equal neighbors which are taken into account in resource reallocations, an embodiment of the invention decreases the signaling and simplifies the resource reallocation calculation procedure, because it decreases the number of networks to which resources have to be allocated.
In an embodiment of the invention, a CM manages “radio environment” of a master TVBD device (TVBD_Own) that the CM serves through a CE. Master TVBD devices in the surroundings are noted as TVBD_Other.
In an embodiment of the invention, the CM categorizes master TVBD devices that surround the TVBD_Own into four categories:
[1] Neighbors: All the TVBD_Other devices that can interfere with the TVBD_Own and that can be interfered with by the TVBD_Own (i.e. mutual interference needed). Noted with TVBD_Nbr. The spec has a set of rules and protocols related to neighbors.
[2] One-sided interferers: Two types of TVBD_Other devices that are not neighbors: ones that can interfere with the TVBD_Own (noted with TVBD_I_Src), others that can be interfered with by the TVBD_Own (noted with TVBD_I_Dst). The spec has a set of rules and protocols related to one-sided interferers.
[3] Follow-up TVBDs: TVBD_Other devices that are “almost” either neighbors or one-sided interferers. These have potential to become neighbors or one-sided interferers (noted with TVBD_Follow_ups). A TVBD_Other device is categorized as a TVBD_Follow_ups if:
[4] Excluded Candidates: TVBD_Other devices that were in the list from the CDIS but are not neighbors, one-sided interferers or follow up TVBDs. Noted with TVBD_Exc-Cand will not have any specific role in the CM's neighborhood management functionality.
The CM maintains following kind of radio environment information base for each TVBD_Own:
For each member of each list following information is maintained
The following are examples of the information for each category:
Neighbors
[1] Information base per TVBD_Own for each TVBD_Nbr
One-Sided Interferers
[1] Information base per TVBD_Own for each TVBD_I_Src
[2] Information base per TVBD_Own for each TVBD_I_Dst
Step 1302: identifying a potential neighboring wireless network to a wireless network based on information exchanged with a network controller serving the potential neighboring wireless network; and
Step 1304: sending a reporting interferer request to the network controller serving the potential neighboring wireless network in response to determining that the potential neighboring wireless network is an interferer network to the wireless network.
Step 1352: receiving a reporting interferer request from a network controller serving a potential neighboring wireless network;
Step 1354: determining whether to accept the reporting interferer request; and
Step 1356: sending a response to the reporting interferer request based on determination.
Using the description provided herein, the embodiments may be implemented as a machine, process, or article of manufacture by using standard programming and/or engineering techniques to produce programming software, firmware, hardware or any combination thereof.
Any resulting program(s), having computer-readable program code, may be embodied on one or more computer-usable media such as resident memory devices, smart cards or other removable memory devices, or transmitting devices, thereby making a computer program product or article of manufacture according to the embodiments. As such, the terms “article of manufacture” and “computer program product” as used herein are intended to encompass a computer program that exists permanently or temporarily on any computer-usable medium or in any transmitting medium which transmits such a program.
As indicated above, memory/storage devices include, but are not limited to, disks, optical disks, removable memory devices such as smart cards, SIMs, WIMs, semiconductor memories such as RAM, ROM, PROMS, etc. Transmitting mediums include, but are not limited to, transmissions via wireless communication networks, the Internet, intranets, telephone/modem-based network communication, hard-wired/cabled communication network, satellite communication, and other stationary or mobile network systems/communication links.
Although specific example embodiments have been disclosed, a person skilled in the art will understand that changes can be made to the specific example embodiments without departing from the spirit and scope of the invention.
