Spectrum coordination controller

A method, wireless controller, and information processing system that define communication channel allocation. Communication channel allocation commands associated with a first network are monitored (102). The first network (102) comprises a plurality of communication frequencies assigned by the communication channel allocation commands. A set of communication frequencies are determined that have been assigned to wireless devices (108) associated with the first network (102) in response to the monitoring. A specification of unused communication frequencies within the plurality of communication frequencies are transmitted to a second network (104) in response to the determining.

FIELD OF THE INVENTION

The present invention generally relates to the field of wireless communications, and more particularly relates to managing allocation of communication frequencies available in a host/primary network to one or more secondary networks.

BACKGROUND OF THE INVENTION

Wireless communication technology has evolved greatly over the recent years. Wireless communication networks can include a variety of different network technologies. Furthermore, one wireless communication network may comprise underused spectrum that another wireless communication network can utilize on a secondary basis. Traditionally, wireless communication technology allows for systems to co-exist independently while sharing a common resource, such as spectrum. However, traditional wireless communication systems do not coordinate the use of the spectrum. Interoperability of systems using the same spectrum can be resolved, for example, through cooperative operation among network devices, e.g., synchronization and spatial scheduling can be employed to mitigate interference associated with network operation.

In situations in which two dissimilar network solutions/technologies are co-located such as a network installed some time ago at a fixed geographic location that can serve as a host for a newly installed second network, the systems do not coordinate the use of critical system resources such as spectrum. Furthermore, the first system may be the primary licensed system that was allocated the spectrum and the second system may be licensed to use the spectrum on a secondary basis; namely, allowed to use the spectrum provided that harmful interference does not degrade the performance of the primary licensed system. However, current technology generally does not provide an efficient and advantageous way for maintaining proper synchronization and critical time-aligned operations between the secondary the host/primary networks for mitigating harmful interference to the host/primary network. For example, current technologies generally do not provide a system in which the operation of a secondary network, i.e., a network that co-exists with an existing system, includes yielding spectrum right-of-way when spectrum scavenged by the secondary network is “recalled” by the host/primary network.

SUMMARY OF THE INVENTION

A method that defines communication channel allocation is disclosed. The method includes monitoring communication channel allocation commands associated with a first network. The first network comprises a plurality of communication frequencies assigned by the communication channel allocation commands. A set of communication frequencies are determined that have been assigned to wireless devices associated with the first network in response to the monitoring. A specification of unused communication frequencies within the plurality of communication frequencies are transmitted to a second network in response to the determining.

In another embodiment, a wireless communication controller is disclosed. The wireless communication controller includes a channel assignment monitor adapted to monitor communication channel allocation commands associated with a first network. The first network comprises a plurality of communication frequencies assigned by communication channel allocation commands. A channel assignment tracker is communicatively coupled to the channel assignment monitor. The channel assignment tracker is adapted to determine, in response to monitoring by the channel assignment monitor, a set of communication frequencies that have been assigned to wireless devices associated with the first network. A channel availability transmitter is communicatively coupled to the channel assignment tracker. The channel availability transmitter is adapted to transmit, in response to determinations by the channel assignment tracker, to a second network, a specification of unused communication frequencies within the plurality of communication frequencies.

In yet another embodiment, an information processing system is disclosed. The information processing system includes a memory and a processor that is communicatively coupled to the memory. The information processing system also includes a wireless communication controller that is communicatively coupled to the memory and the processor. The wireless communication controller includes a channel assignment monitor adapted to monitor communication channel allocation commands associated with a first network. The first network comprises a plurality of communication frequencies assigned by the communication channel allocation commands. A channel assignment tracker is communicatively coupled to the channel assignment monitor. The channel assignment tracker is adapted to determine, in response to monitoring by the channel assignment monitor, a set of communication frequencies that have been assigned to wireless devices associated with the first network. A channel availability transmitter is communicatively coupled to the channel assignment tracker. The channel availability transmitter is adapted to transmit, in response to determinations by the channel assignment tracker, to a second network, a specification of unused communication frequencies within the plurality of communication frequencies.

An advantage of the various embodiments of the present invention is that the allocation of available spectrum in one wireless communication network to one or more additional wireless communication networks is coordinated. This coordination prevents the degradation of service quality of the host incumbent primary network. The various embodiments of the present invention also maintain proper synchronization and critical time-aligned operations between the host/primary and the secondary networks to mitigate harmful interference to the host/primary network. The various embodiments of the present invention also increase the overall spectral efficiency of the shared spectrum.

DETAILED DESCRIPTION

The terms “a” or “an”, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

The term “wireless device” is intended to broadly cover many different types of devices that can wirelessly receive signals, and optionally can wirelessly transmit signals, and may also operate in a wireless communication system. For example, and not for any limitation, a wireless communication device can include (but is not limited to) any one or a combination of the following: a two-way radio, a cellular telephone, a mobile phone, a smartphone, a two-way pager, a wireless messaging device, a laptop/computer, automotive gateway, or a residential gateway.

Wireless Communication System

According to one embodiment of the present invention as shown inFIG. 1a wireless communication system100is illustrated.FIG. 1shows a plurality of networks102,104. Although only two networks102,104are shown, the wireless communication system100can comprise additional networks. In one embodiment, one of the networks102is a host/primary network and one or more of the additional networks are secondary networks104. In one embodiment, a host/primary network can be an underlay network and a secondary network can be an overlay network. The host/primary network102is assigned RF spectrum that is divided into channels that can potentially be used by the secondary network(s)104. Throughout this discussion the terms “host” and “primary” that refer to, for example, host/primary network102, are used interchangeably.

Each of the wireless communication networks102,104can include one or more communication networks112,114such as a circuit service network and/or a packet data network. The communication networks112,114can either be wired or wireless. Throughout the following discussion the communication networks112,114are referred to as wired communication networks112,114as a non-limiting example.

The wireless communications standard of the networks102,104coupling bases stations116,118to mobiles108/110can comprise Code Division Multiple Access (“CDMA”), Time Division Multiple Access (“TDMA”), Global System for Mobile Communications (“GSM”), General Packet Radio Service (“GPRS”), Frequency Division Multiple Access (“FDMA”), other IEEE 802.16 standards, Orthogonal Frequency Division Multiplexing (“OFDM”), Orthogonal Frequency Division Multiple Access (“OFDMA”), Wireless LAN (“WLAN”), WiMAX, or the like. The wireless communications networks102,104are able to be an IP or SIP based connectivity network, which provides data connections at much higher transfer rates then a traditional circuit services network. These networks are able to comprise an Evolution Data Only (“EV-DO”) network, a General Packet Radio Service (“GPRS”) network, a Universal Mobile Telecommunications System (“UMTS”) network, an 802.11 network, an 802.16 (WiMAX) network, Ethernet connectivity, dial-up modem connectivity, or the like.

A circuit services network is able to provide, among other things, voice services to the wireless devices108,110communicatively coupled to one or both of networks102,104. Other applicable communications standards include those used for Public Safety Communication Networks including TErrestrial TRunked rAdio (“TETRA”) and P25 Trunking. The following discussion uses an example of an host/primary network102providing Land Mobile Radio System (“LMRS”) services such as P25 Trunking and a secondary network104providing WiMAX communication system services. It should be noted that these network technologies are only used as an illustrative example and do not limit further embodiments of the present invention.

Each of the wireless communication networks includes a plurality of base stations116,118. Each of the base stations116,118is communicatively coupled to an information processing system120,122such as a site controller120,122. Each of the site “call” controllers120,122includes a channel assignment manager124,128and a call manager126,130. The channel assignment manager124,128and the call manager126,130are discussed in greater detail below. The wireless communication system100also includes one or more information processing systems132that monitor control messages, such as channel assignment and de-assignment messages sent between the channel assignment manager124of the host/primary network102and the base stations116of the host/primary network102. These control messages can be intercepted by the information processing system132or interact with an interface to the site controller120such as (but not limited to) an API or a billing interface to monitor assignment information.

It should be noted that, in one embodiment, the functions of the information processing system(s)132can also be implemented at the Host site controller120. In one embodiment, the control messages are sent through the wired communication network112and passively monitored by a monitor link106. It should be noted that the monitor link106can be wireless or wired (such as fiber optic).

The information processing system132, in one embodiment, includes one or more spectrum coordination controllers (“SCC”)134that coordinates the allocation of available spectrum/communication frequencies not used by the host/primary network102to the secondary network104. The information processing system132includes a computer program storage medium that includes a channel assignment monitor136, a channel assignment tracker138, a channel availability transmitter140, a second channel assignment monitor150, a second channel availability transmitter152, and a channel assignment database142. The SCC134and each of its components are discussed in greater detail below. Specifications of channels that are unassigned by the host/primary network102are communicated to the secondary network104through a data link107. It should be noted that the data link107can be wireless or wired (such as fiber optic).

Dynamic Spectrum/Communication Channel Allocation Coordination

As discussed above, in one example, the existing host/primary network102is a narrowband voice system (e.g., P25 LMRS) and the secondary network104is a wide band data-centric solution used to transport content such as video (e.g., WiMAX). In one example, the host/primary network102follows a given channel filling algorithm for allocating communication frequencies. For example, channel selection can start from the low end of the band to the high end of the band or vice versa. The SCC134of one embodiment, as discussed above, is communicatively coupled to both the host/primary network102and the secondary network104so as to allow the SCC134to monitor control messages of the host/primary network102and provide available spectrum information to the secondary network104.

The channel assignment monitor136monitors spectrum/communication channel allocations at the host/primary network102. For example, the channel assignment monitor136monitors for and detects channel allocation and de-allocation commands, which are generally referred to herein as channel allocation commands, issued by the channel assignment manager124at the host/primary network102. The SCC134analyzes the monitored channel allocation and de-allocation information and stores the information in a channel assignment database142. For example, the SCC134determines which communication frequencies are currently assigned/unassigned in the host/primary network102and tracks these assignments via the channel assignment database142.

A channel assignment tracker138determines, in response to the monitoring of channel assignments, a set of communication frequencies that have been assigned to wireless devices associated with the host/primary network102. Based on the channels assigned by the host/primary network102, the channel assignment tracker is able to determine the communication frequencies or range of channels that can be utilized by the secondary network104. It should be noted that the term “spectrum” refers to channel frequencies that are used within a network for communication/data services. Examples of channel frequencies identified by the SCC134across various base stations of sites are illustrated inFIG. 2. Examples of channel frequencies identified by the channel assignment monitor136as being either assigned/unassigned are illustrated inFIG. 3.FIG. 2shows a table202,204,206,208,210for each monitored site/base station116in a primary network(s)102. Each table202,204,206,208,210illustrates the frequency allocation used by the site within the host network. For example, the table202for Site A indicates that Site A utilizes Channels 1-3. Channel 1 has a transmit frequency of T11 and a receive frequency of R11. Channel 2 has a transmit frequency of T2 and a receive frequency of R2. Channel 3 has a transmit frequency of T14 and a receive frequency of R14.

Once the SCC134determines the spectrum in use (or not in use) by the host/primary network102, the channel availability transmitter140transmits, in response to determinations by the channel assignment tracker138, to the secondary network104, a specification of unused communication frequencies within the plurality of communication frequencies.

FIG. 3shows a table302,304,306,308,310for each of the sites inFIG. 2illustrating potentially available spectrum that can be utilized by the secondary network102. It is important to note that channel assignments may not be contiguous and if a channel is deemed available, the adjacent spectrum below and above the channel to neighboring channels can also be utilized by a secondary network. For example, these tables show that the minimum frequency of the host/primary network102is n and the maximum frequency is n+x. As discussed above with respect toFIG. 2, the channel assignment monitor136has determined that the following frequencies T2, T11, T14, R2, R11, and R14 have been allocated to Site A and at some point may be available for use. The tables ofFIG. 3also identify the delta, or separation, between each frequency. For example, the table302associated with Site A shows that the delta between T2 and T11 is 1.80 MHz.

The channel assignment tracker138has also identified portions of the spectrum utilized by each of the sites of the host/primary network102that can potentially be used by the secondary network104, as shown inFIG. 3. For example, the spectrum between T2 and T11 corresponding to the delta of 1.80 MHz has been identified by the channel assignment tracker138as potential spectrum that can be utilized by the secondary network104. Each of the rows inFIG. 3that include underlined values in the “delta” column such as row303illustrates potential spectrum that is not utilized by the system and that can be used by the secondary network104. In particular, underlined numbers indicate potential blocks of spectrum that is not used by the host/primary network102and may be suitable for the secondary network104.

FIG. 4illustrates spectrum400that is allocated/non-allocated by the entire host/primary network comprising sites A, B, C, D, and E associated with the tables ofFIG. 2andFIG. 3.FIG. 4shows the receiver and transmit frequency pairs separated by a guard band402. In the n to n+x band, the guard band402is 4 MHz wide and is located from T(n+j)404to R(n)406or the difference between the highest transmit frequency and the lowest receive frequency of the primary system. As can be seen fromFIG. 4, the host/primary network102comprises spectrum that can be utilized by the secondary network104. The secondary network104determines the location of a “home” or “control” channel, perhaps in the guard band402or in some of the other identified holes. Thus, in real-time the “home” channel can be relocated or can grow or shrink in a contiguous and non-contiguous manner depending on the usage requirements of the host/primary network102.

The SCC134communicates spectrum information to the secondary network104via the link107(in this example). The channel assignment manager128of the secondary network104receives this information and determines the available frequencies in the host/primary network102that it can utilize. As discussed above, the secondary network104, in one example, utilizes orthogonal frequency division multiplexing (“OFDM”), which is used to create a wideband modulus comprising a multiplicity of narrowband channels. A single narrowband channel can occupy the same amount of bandwidth required to support a single narrowband voice channel of the host/primary network102, thereby facilitating filling of the band on a per channel basis.

The channel assignment manager128of the secondary network also establishes a home or control channel within spectrum that has the highest probability of going unused by the host/primary network such as in the guard band area402illustrated inFIG. 4. A control channel of the secondary network allows a wireless device to transmit call request, receive traffic channel assignments, and perform other similar functions. In a further embodiment, the SCC134includes a second channel assignment monitor150that determines the frequency or frequency ranges that are being utilized by the secondary network104as its control channel. The SCC134of that further embodiment then updates its channel assignment database142accordingly. For example, the second channel assignments monitor150monitors the channel allocation commands and control information issued by the channel assignment manager128of the secondary network104. In other words, the second channel assignment monitor150is adapted to accept a message from at least one secondary network104that comprises a second specification of communication frequencies from the plurality of communication frequencies that are not to be used by the host/primary network102. Such operations by this further embodiment allow the SCC134to identify spectrum being utilized by the secondary network104and provide instructions to the host/primary network102, in embodiments that support such instructions, to not use the spectrum currently used by the secondary network104.

When the call manager130of the secondary network104receives a call request from a wireless device110, a channel assignment manager128of a further embodiment is able to allocate a communication channel to the device110from the set of available communication frequencies identified by the SCC134. The second channel assignment monitor150of this further embodiment detects this channel assignment and updates its channel assignment database142accordingly. A second channel availability transmitter152then transmits the specification of communication frequencies that are not to be used by the host/primary network102to the host/primary network102.

As can be seen, one embodiment of the present invention is advantageous in that it increases the overall spectral efficiency of networks by providing real-time coordinated use of common spectrum between separate networks incorporating potentially dissimilar networking technologies. One embodiment of the present invention monitors spectrum allocation commands and control information associated with an existing host/primary network to identify unused spectrum. One embodiment of the present invention then instructs a secondary network to utilize the unused spectrum by adapting to and scavenging spectrum not used by the host/primary network at any given time.

In a further embodiment, it should be noted that the allocation commands associated with the host/primary network102monitored by the SCC134can also comprise commands indicating that a particular frequency or frequency range(s) is to be prevented from being utilized by the secondary network104. In such one embodiment, the SCC134does not include that particular frequency or frequency range in the listing of available frequencies sent to the secondary network104. In one embodiment, the secondary network104can also issue a command that instructs the host/primary network104to not allocate a particular frequency or frequency range(s). The SCC134, in this embodiment, receives the command and instructs the host/primary network102accordingly.

As discussed above, the available spectrum of the host/primary network102is dynamic. In other words, the available spectrum changes over time. For example, a wireless device108at the host/primary network102can request a call setup. The call manager124at the host/primary network102and the channel assignment manager124allocates a particular channel to the device108to service that call. However, that channel may be currently in use by the secondary network104.

In one embodiment, the SCC134detects an allocation command for that particular channel. Therefore, the SCC134issues a command to the secondary network104to de-allocate that channel. If the secondary system is using that channel, it is de-allocated by the secondary network104. Hence, secondary use policies determining how the secondary network104utilizes the available spectrum can be enforced. In one embodiment, the secondary network104can be instructed to yield right-of-way to the host/primary network so that the host/primary network102gets priority over the use of the spectrum. It is obvious to those skilled in the art that other policies/etiquette can be developed and enforced. For example, the device108can issue an emergency call request that must be assigned immediately. If these two systems (host102and secondary104) know about each other they can reserve the other's spectrum during normal conditions, but if an emergency call was needed and the host/primary network102does not have any available channels, the secondary network104releases any reserved spectrum in the host/primary network104

FIG. 5shows a transactional diagram illustrating this process. Time is depicted inFIG. 5by the vertical scale. At time T0, a wireless device108subscribing to the host/primary network102submits a call request520to its host base station116. At time T1, the call request522is sent to the host core506and the call request is granted at time T2. At time T3, the channel assignment manager124of the host/primary network102allocates a channel to the requesting device108. The SCC134, at time T3′, detects the channel assignment via an allocation command528, which is monitored by the monitor link106. At time T3′, the SCC134also instructs the base station118at the secondary network104to not use the channel. In the event that the secondary network104was using the channel, the base station118at the secondary network104, at time T4, performs the de-allocation of that channel. The base station116at the host/primary network102, at time T5, initiates use of the channel. The wireless device108of the host/primary network102adjusts its synthesizer to the channel at time T6so that the call requested by the device108can be made.

Exemplary Wireless Device

FIG. 6is a block diagram illustrating a detailed view of the wireless device108,110according to one embodiment of the present invention. It is assumed that the reader is familiar with wireless communication devices. To simplify the present description, only that portion of a wireless communication device that is relevant to the present invention is discussed. The wireless device108operates under the control of a device controller/processor602, that controls the sending and receiving of wireless communication signals. In receive mode, the device controller602electrically couples an antenna604through a transmit/receive switch606to a receiver608. The receiver608decodes the received signals and provides those decoded signals to the device controller602.

In transmit mode, the device controller602electrically couples the antenna604, through the transmit/receive switch606, to a transmitter610. It should be noted that in one embodiment, the receiver608and the transmitter610are a dual mode receiver and a dual mode transmitter for receiving/transmitting over various access networks providing different air interface types. In another embodiment a separate receiver and transmitter is used for each of type of air interface.

The device controller602operates the transmitter and receiver according to instructions stored in the memory612. These instructions include, for example, a neighbor cell measurement-scheduling algorithm. The wireless device108, also includes non-volatile storage memory614for storing, for example, an application waiting to be executed (not shown) on the wireless device108.

Information Processing System

FIG. 7is a block diagram illustrating a more detailed view of an information processing system132. It should be noted that although the following discussion is with respect to the information processing system130comprising the SCC134, the information processing system132is based upon a suitably configured processing system adapted to implement one embodiment of the present invention. For example, a personal computer, workstation, or the like, may be used. The information processing system132includes a computer702. The computer702has a CPU processor704that is connected to a main memory706, a mass storage interface708, a man-machine interface710, and network adapter hardware716. A system bus714interconnects these system components.

The main memory706includes the SCC134, which comprises a channel assignment monitor136, a channel assignment tracker138, a channel availability transmitter140, a channel availability transmitter, a second channel assignment monitor150, a second channel availability transmitter152, and a channel assignment database142, which have all been discussed in greater detail above.

The main memory706also includes the channel assignment database142. Although illustrated as concurrently resident in the main memory706, it is clear that respective components of the main memory706are not required to be completely resident in the main memory706at all times or even at the same time. Furthermore, one or more of these components can be implemented as hardware.

The mass storage interface708can store data on a hard-drive or media such as a CD or DVD. The man-machine interface710allows technicians, administrators, and other users to directly connect to the information processing system130via one or more terminals718. The network adapter hardware716, in one embodiment, is used to provide an interface to the communication network112,114. Embodiments of the present invention are able to be adapted to work with any data communications links, including present day analog and/or digital techniques or via a future networking mechanism.

Process of Coordinating Spectrum Allocation Between an Underlay Network and an Overlay Network

FIG. 8is an operational flow diagram illustrating a process of coordinating spectrum use between a host/primary network102and one or more secondary networks104. The operational flow diagram ofFIG. 8begins at step801and flows directly to step802. The SCC134, at step802, analyzes the host/primary network102and determines the frequency spectrum being used within the network102. In one embodiment, the SCC134can analyze initial data to help identify the host/primary network102that it is to center on. However, this is not required. The SCC, at step804, monitors the host/primary network102for allocation and de-allocation commands and control information. The SCC134, at step806, determines if an allocation command has been detected. If the result of this determination is negative, the SCC134continues to monitor for allocation commands and control information. If the result of this determination is positive, the SCC134, determines at step807, if the host/primary network de-allocated a channel. If the host/primary network did de-allocate a channel, the processing continues by the SCC instructing, at step808, the secondary controller to use the channel de-allocated by the host network. After such instruction, or if the SCC determined that the host/primary network did not de-allocate a channel, the SCC updates, at step809, its channel assignment database142.

The SCC134, at step810, determines a set of frequencies and/or frequency ranges that are currently unused at the host/primary network102. The SCC134, at step812, transmits the set of frequencies and/or frequency ranges to the secondary network104. As discussed above, the host/primary network102can issue a command to base stations in that network that is monitored by the SCC134that indicates one or more frequencies or frequency ranges are used by the host network, and therefore are not to be utilized by the secondary network104.

The secondary network104, at step813, receives the set of frequencies and/or frequency ranges and may designate one or more of the frequencies as a control/home channel. In one embodiment, the SCC134assumes that all frequency ranges indicated to the secondary overly network104as available are used by that network. In further embodiments, the SCC134is able to identify the frequency(s) utilized by the secondary network104designated as the control/home channel by, for example, monitoring assignments made by the secondary network104. In either embodiment, the SCC134, at step816, updates its channel assignment database142accordingly. The wireless subscribers110of the secondary network104, at step816, are also updated with the control/home channel information.

The SCC134, at step818, monitors the host/primary network102for channel assignments and updates its channel assignment database142accordingly. For example, if the SCC134detects that the host/primary network102has assigned a channel to a wireless device108, the SCC134updates the channel assignment database. It should be noted that the SCC134is also continuing to monitor the channel assignments and deassignments at the host/primary network102. The SCC134, at step820, determines if the host/primary network102is allocating channels, which can be a home (control) or expansion channel (e.g., a channel used by the secondary network104as a traffic channel). If the result of this determination is negative, the SCC134continues to monitor for channel assignments/de-assignments by the host/primary network102. If the result of this determination is positive, the control flows to entry point A ofFIG. 9.

The SCC134, at step902, instructs the secondary network104that the channel is no longer available for use and must de-allocate that channel for its use. The secondary network104, at step904, instructs the wireless device110assigned to that particular channel to vacate the channel. If the channel is a home/control channel then all of the wireless devices110subscribing to the secondary network104are instructed to vacate the channel. The wireless devices110, at step906, attempt to resynchronize with their new home channel. The wireless devices110, at step908, determine if the home channel is available. If the result of this determination is positive, the control flows back to step818ofFIG. 8. If the result of the determination is negative, the wireless devices110, at step910, await for home channel allocation instructions from the secondary network104. Once instructions are received the wireless devices try to synchronize with the new home channel at step908.

When the SCC134instructs the secondary network104to de-allocate the channel or channels at issue, the site controller122of the secondary system104, at step912, determines if another channel is available for the secondary network104to use as a home channel. The secondary network104, at step916, notifies its wireless subscribers110that spectrum from the host/primary network104is not going to be used. The control flow returns to step906. If the result of the determination at step912is positive, the wireless subscribers110of the secondary network104, at step920, proceed to use the indicated channel or channels. The control flows back to step818ofFIG. 8. It should be noted that after the SCC134instructs the secondary network104to de-allocate the channel or channels at issue, the secondary network104can determine select a new channel(s) to use.