Patent Application
20110151885
During periods when a cell within a wireless network suffers excessive congestion, cellular capacity (i.e., wireless resources) within that cell typically become scarce. Excessive congestion within a cell may result from the simultaneous consumption of a large percentage of the available wireless resources within the cell. Various events within a cell are capable of causing such consumption; such as an emergency situation which results in an abnormally high call volume within the cell, an abnormally high number of devices simultaneously located within the cell, etc.
Scarcity of wireless resources often causes degradation of service within a cell. For example, during periods of excessive congestion, wireless resources may not be adequate to fulfill requests from devices within the cell for new wireless connections and/or to accept handoffs when devices with ongoing wireless connections approach or enter the cell. Wireless connections may include cellular calls between mobile communications devices, data transfers between mobile devices, and the like. The inability to facilitate new connections may become problematic, for example in crisis situations where emergency responders may require new connections in order to exchange vital information. Contributing to the problem is the fact that preemption of ongoing cellular calls is often prohibited, precluding the disconnection of those calls to allow connections for the emergency responders to be fulfilled. Congestion within a cell may also cause service quality to degrade below guaranteed levels for premium subscribers.
A typical solution employed during periods of excess cell congestion is to provide high priority users, such as emergency responders, priority access to wireless resources as they become available. However, a major shortcoming to this approach is that resources may become available slowly during such periods of congestion, causing holding periods for resource availability to become excessive. Thus, emergency responders may still be prevented from gaining timely access to wireless resources.
A radio resources management algorithm, through a process of function evaluation and/or optimization, determines and assigns resource priority values to wireless resource requests. The requests may be arranged within a priority queue in accordance with the priority values. A new priority queue may be created by the algorithm, or the newly created optimized priority values may replace those assigned in an existing resource queue, for example a resource queue controlled by an existing connection admission control (CAC) algorithm. The priority queue may control access to wireless resources that are typically reserved for handing off ongoing calls between neighboring cells. The disclosed algorithm may supplement or replace an existing CAC algorithm, such as a “first come first serve” algorithm for handoff resource allocation.
The disclosed algorithm may also determine whether sufficient spare handoff resources are available to fulfill a resource request. If sufficient resources are not available, the disclosed algorithm may implement one or more congestion control mechanisms designed to free up handoff resources. If sufficient resources are not available to fulfill a resource request, the resource request may be accepted and queued if it is of sufficiently high priority, or may be rejected if it is of low priority.
The disclosed algorithm may be initiated in response to a congestion condition within a network. Alternatively, the algorithm may operate continuously as a supplement to or replacement for an existing connection admission control algorithm. Continuous operation may be advantageous, for example in a scenario where full time prioritization is desirable. The algorithm may be deployed to prioritize resource requests on an individual network element, for example a base transceiver station. The algorithm may also be deployed to function in concert with a centralized control, such as a network resource admission control, to provide coordinated prioritization of resource access to particular portions of a network, or network wide.
A new radio resources management algorithm, through a process of function evaluation and optimization, determines and assigns resource priority values to requests for access wireless resources. The requests may be arranged within a priority queue in accordance with the optimized priority values. For example, during a period of excessive congestion within a cell, there may be little to no wireless resources available to fulfill new connection requests and/or handoff requests. In such a scenario, a wireless resource request by an emergency responder within the cell may be delayed or even rejected. The radio resource management algorithm may assign a high priority to the wireless resource request of the emergency responder so it is processed before all other pending and new requests, and may also act to relieve the congestion within the cell by employing one or more congestion control mechanisms.
The radio resource management algorithm may be configured to prioritize resource requests for a cell provisioned on an individual network element, for example a base transceiver station. The radio resource management algorithm may be implemented in the hardware and/or software of such a network element. In another embodiment, the radio resource management algorithm may be configured to operate cooperatively with an existing connection admission control (CAC) algorithm. In an embodiment, the radio resource management algorithm may be initiated only in response to specific conditions within a cell, for example a congestion condition. Alternatively, the radio resource management algorithm may operate continuously, prioritizing all resource requests received for a cell, for example in a scenario where full time prioritization is desirable. In another embodiment, the radio resource management algorithm may be configured to function in concert with a centralized control, such as a network resource admission control, in order to provide coordinated prioritization of resource access to particular portions of a network, such as a group of cells located within a geographic region, or to provide coordinated prioritization of resource access across an entire wireless and/or wireline network.
The requesting device may be a mobile device configured to communicate via a wireless network, examples of which include a portable phone (e.g., a cell phone or the like, a smart phone, a video phone), a portable computing device (e.g., a laptop), a personal digital assistant (PDA), a portable email device, a portable gaming device, a portable television, a portable DVD player, a portable media player (e.g., a portable music player, such as an MP3 player, a walkmans, etc.), a portable navigation device (e.g., a GPS compatible device, an A-GPS compatible device, etc.), or a combination thereof. The requesting device may also be a device that is not typically thought of as portable, such as, for example, a public computing device, a navigation device installed in-vehicle, a set top box, or the like. The requesting device may also include devices that are not conventional computing devices, such as, for example, a kitchen appliance, a motor vehicle control (e.g., a steering wheel), or the like.
The network device may be any appropriate device configured to provide services in a wireless and/or wireline communications network, examples of which include a base transceiver station (BTS), a base station controller (BSC), a mobile switching center (MSC), a service control point (SCP), an access/service gateway (A/S GW), a service GPRS support node (SGSN), a gateway GPRS support node (GGSN), a home location register (HLR), a visitor location register (VLR), an authentication center (AuC), a cell broadcast center (CBC), a domain name server (DNS), a firewall, and the like.
The resource requested is most often a portion of wireless bandwidth, typically corresponding to one or more wireless radio channels within a frequency band assigned to a particular cell. A wireless channel may be used for a variety of services, for example a cellular voice call, a data transfer connection, a video and/or audio streaming session, or any other form of service that may be provisioned over a wireless network connection.
Requests for wireless resources are typically one of two varieties; a new resource request as received at step 102 or a handoff resource request as received at step 104. A new resource request may indicate that a device within the cell is attempting to establish a new connection using wireless resources of the cell. A handoff resource request may indicate that a device currently connected to a resource of a neighboring cell is requesting that its connection be handed off from the resource of the neighboring cell to a wireless resource in the cell the request is directed towards. The handoff resource request may be of a hard handoff nature or a soft handoff nature. Hard and soft handoffs are well known in the art and will not be described in detail herein.
When a new resource request and/or a handoff resource request are received at steps 102 and/or 104 respectively, the radio resource management algorithm may evaluate functions at step 106. The functions evaluated at step 106 may include a handoff priority function (HOP), a new call priority function (NCP), a global priority function (GPF), and the like, or any combination thereof. The radio resource management algorithm may evaluate one or more of these functions as necessary. A decision of which function(s) to evaluate may be based on current wireless resource usage and/or availability conditions in a cell, neighboring cells, the network as a whole, or any combination thereof. For example, the functions may be configured to perform a more rigorous evaluation during periods of excessive congestion in the cell. The functions may be configurable by the radio resource management algorithm, such that they may be evaluated using a variety of factors, for example: a profile class of a subscriber and/or a device associated with the resource request; quality of service (QoS) parameters that may be associated with the profile class, the type of resource request, etc.; key performance indicators, such as those monitored by a base transceiver station; a quality of service control indicator (QCI); a critical indicators (CI), such as those declared by a homeland security agency and/or operator when wireless resources are extremely congested; a roaming indicators (RI) (in roaming scenarios from different operators special payment options might apply an hence would impact priority); a device indicator (DI), which may indicate a type of device, such as cell phone, laptop, etc; and the like.
How the functions are configured prior to their evaluation may be adaptively altered by the radio resource management algorithm, for example by changing which factors are selected for evaluation, the weighting given to individual factors, and the like. In the process of adaptively altering the functions, the radio resource management algorithm may take into account information pertaining to the wireless resources of the cell, for example statistics and/or other data pertaining to wireless resource use and/or availability in the cell. The information may be historical in nature, or may be collected in real time. The radio resource management algorithm may also take into account similar information received and/or recorded from neighboring cells. Neighboring cell data may be received from a network component in the neighboring cell, for example a base transceiver station, or from another device within the network, such as a network resource admission control. Information from a network device such as a network resource admission control may also include network-wide information pertaining to wireless and/or wireline resources.
Evaluating the functions enables the radio resource management algorithm to determine a resource priority value for the resource request. For example, evaluating a new call priority function for a new resource request received at step 102 may result in a resource priority value for the new call request, while evaluating a handoff priority function for a handoff resource request received at step 104 may result in a resource priority value for the handoff request. In an embodiment, a global priority function may be evaluated as a summation of HOP and NCP functions, and the factors evaluated may contain information collected from a number of network devices, for example a network of interconnected base transceiver stations. It is to be noted that the functions and factors listed herein are merely examples, and the scope of the instant disclosure should not be limited thereto.
At step 108, the resource priority values resulting from the functions evaluated at step 106 may be optimized. The optimization process may be carried out in accordance with one or more constraints, such as a probability of dropping (Pd) and/or a probability of blocking (Pb). For example, it may be advantageous to minimize the probability of dropping when a cell is currently receiving a disproportionately high volume of handoff resource requests. Similarly, it may be advantageous to minimize the probability of blocking when a cell is currently receiving a disproportionately high volume of new resource requests. The probability values may be determined in real time by the radio resource management algorithm in accordance with other factors, may be pre-determined and accessed from storage and memory when the optimization process is performed, or a combination thereof. In another embodiment, the optimization process of step 108 may be omitted. It is to be noted that the optimization constraints listed herein are merely examples, and the scope of the instant disclosure should not be limited thereto.
Once the resource priority values have been optimized or the optimization process has been omitted, the resource priority value is assigned to the resource request. The resource priority value may replace an earlier assigned priority value, for example a resource priority (i.e., QCI) assigned in accordance with 3GPP standards (TS 23.203).
After, or concurrently with, the evaluation, optimization, and assignment of the resource priority value, the radio resource management algorithm may, at step 112, estimate a quantity of wireless resources required to fulfill the resource request. The quantity of wireless resources required to fulfill the resource request may be estimated in accordance with the type of the resource request, the current modulation and coding scheme (MCS) level of the requesting device, and the like. The estimate will typically be calculated in accordance with the particular interface technology of the cell the request is directed to. For example, the quantity of wireless resources required to fulfill a resource request in an LTE wireless cell may be estimated (i.e., calculated) in terms of physical resource blocks (PRBs). A resource request to an LTE wireless cell will typically specify an amount of required cellular network bandwidth (i.e., resources), Breq. A modulation and coding scheme (MCS) level is typically associated with the requesting device. The estimated quantity of wireless resources required to fulfill the LTE resource request, in other words the number of physical resource blocks required (NPRBreq) to fulfill the request, may be calculated using Breq and the bandwidth of the current MCS level (BPRB(MCS)), where
Once the quantity of wireless resources required to fulfill the resource request has been estimated, the estimate may be compared against the total amount of wireless resources available in the cell, at step 114. The total amount of available wireless resources in a cell will typically be calculated in accordance with the particular interface technology of the cell the request is directed to. Returning to the LTE example, the calculation of available physical resource blocks may be based upon resource block usage by existing resource connections (e.g., cellular calls, data connections, streaming sessions, and the like) as measured by the base transceiver station the cell is provisioned on. The number of free physical resource blocks (NPRBfree) can then be determined using
NPRBfree=NPRBtot−NPRBnrt−NPRBrt,
where NPRBtot may be the number of total PRBs in the cell, NPRBrt is the number of PRBs dedicated to non real-time resource connections, and NPRBrt is the number of PRBs dedicated to real-time resource connections. The radio resource management algorithm may determine NPRBtot from resource data provided by the network hardware and/or software on which the cell is provisioned, for example a base transceiver station. In determining NPRBtot, the radio resource management algorithm may employ various limitations and/or filters to the resource data. For example, in an embodiment, the radio resource management algorithm may determine the total number of physical resource blocks that are presently reserved for handoff traffic, filtering out other available and/or reserved PRBs, thereby limiting NPRBtot to those available reserved handoff resources for purposes of calculating NPRBfree. In other words, the radio resource management algorithm may determine whether sufficient spare wireless handoff resources are available to fulfill a wireless resource request. In another embodiment, NPRBtot may be determined including all available wireless resources in the cell, with no limitations and/or filters. It is to be noted that the equations and/or techniques used to calculate (i.e., determine) the quantity of wireless resources required to fulfill a resource request and the total amount of available wireless resources in a cell are discussed herein with reference to an example embodiment in a long term evolution (LTE) wireless network, and the scope of the instant disclosure should not be limited thereto. Variations of these equations and/or techniques, applicable to other interface technologies, are contemplated and intended to be included within the scope of the instant disclosure.
If the comparison of step 114 reveals that the total amount of wireless handoff and/or other resources available in the cell meets or exceeds the estimated quantity of wireless resources required to fulfill the resource request, the resource request may be accepted and arranged in a priority queue at step 116. A wireless resource request may be arranged within the queue in accordance with its assigned resource priority value. For example, a national security/emergency preparedness, law enforcement (NSEP-LE) responder may be assigned the highest resource priority value among resource requests received at a network device employing the radio resource management algorithm. The NSEP-LE resource request may be arranged in the priority queue at the highest, or first/next served position, ahead of all remaining resource requests in the priority queue.
The radio resource management algorithm may create and administer a new priority queue for prioritizing access to wireless resources. In an embodiment, a new priority queue created by the radio resource management algorithm may be operated on the hardware and/or software of a wireless network device the cell is provisioned on, such as a base transceiver station, independently from an existing connection admission control (CAC) algorithm already in place on the network device. In such an embodiment, the radio resource management algorithm may monitor its priority queue and provide resource admission decisions to the existing CAC algorithm. In another embodiment, the priority queue created by the radio resource management algorithm may supplement or replace an existing resource admission queue operated by an existing CAC algorithm, in essence acting as a “shadow queue.” In yet another embodiment, the resource priority values evaluated and/or optimized by the radio resource management algorithm may supersede priority values assigned by an existing CAC algorithm to resource requests placed in an existing resource admission queue operated by the existing CAC algorithm. The priority queue created by the radio resource management algorithm may be used to control access to wireless resources, for example wireless handoff resources, by determining the order resource requests are fulfilled in through their arrangement within the priority queue.
The time for which a resource request may remain in the priority queue may be limited in accordance with a maximum queuing time. The maximum queuing time may be determined by the radio resource management algorithm, by another device within the cellular network (e.g., a network device configured with a network resource admission control (NRAC)), or a combination thereof. If a resource request remains in the priority queue after the maximum allowed queuing time has been reached, the resource request may be rejected and/or deleted from the priority queue.
If the comparison of step 114 reveals that the total amount of wireless handoff and/or other resources available in the cell does not meet the estimated quantity of wireless resources required to fulfill the resource request, the radio resource management algorithm may cause one or more congestion control mechanisms to be executed at step 118. Congestion control mechanisms may be used to accelerate the release (i.e., “freeing up”) of wireless resources, for example wireless handoff resources, that are currently consumed by other devices, processes, etc. The radio resources management algorithm makes available a number of congestion control mechanisms, including adjusting a handoff resources reservation percentage, downgrading a service level of at least one existing resource consumer, applying a handoff delay to one or more additional resource requests in accordance with respective resource priority values, rejecting one or more additional resource requests in accordance with respective resource priority values, and releasing a soft handoff link resource. The radio resource management algorithm may execute a single congestion control mechanism, or may execute several congestion control mechanisms simultaneously. During simultaneous execution, combinations of single or multiple congestion control mechanisms may be executed in a variety of ways, for example on a per quality of service level basis, a type of resource request basis, and the like. It is to be noted that the congestion control mechanisms listed herein are merely examples, and the scope of the instant disclosure should not be limited thereto.
An example congestion control mechanism is adjusting a handoff resources reservation percentage. The wireless resource management algorithm may be configured to reserve a percentage of a cell's wireless resources for fulfilling handoff resource requests. When an abnormally high volume of handoff resource requests are received by a particular cell, the available reserved handoff resources may be rapidly exhausted, resulting in congestion in the cell. In response to the congestion condition, the radio resources management algorithm may increase the percentage of wireless resources reserved for handoff requests. Alternately, the radio resource management algorithm may direct an increase of a percentage of wireless resources reserved for handoff requests by an existing connection admission control (CAC) algorithm acting in concert with the radio resource management algorithm. As wireless resources are released back to the cell, they may be reserved in accordance with the increased percentage of wireless resources reserved for handoff requests. In turn, a larger volume of handoff resource requests may be fulfilled from the increased quantity of available handoff resources. However, it is possible that fewer new resource requests may be fulfilled as a result of a corresponding decrease in the quantity of wireless resources available to fulfill resource requests other than handoff resource requests.
Another example of a congestion control mechanism is downgrading a service level of at least one existing resource consumer. Service levels may be downgraded for existing connections to wireless cell resources, may be downgraded for individual new or handoff resource requests, or a combination thereof. A service level downgrade may be affected in a number of ways. A service level downgrade may be made in accordance with a quality of service (QoS) level, a modulation and coding scheme (MCS) level, a resource priority level assigned to the connection or request by the radio resource management algorithm, and the like. For example, a connection guaranteed a platinum level QoS may be downgraded to a gold level QoS, while a gold level QoS may be downgraded to a silver level QoS, and so on. A service level downgrade may involve, for example decreasing the amount of wireless radio bandwidth allocated to a connection. If the connection is provisioned in accordance with a guaranteed bit rate (GBR) tier, the downgrade may involve reprovisioning the connection at the next lowest tier. The radio resource management algorithm may determine which connections and/or requests are associated with services that are the least sensitive to increased delay, for example non-real time web browsing, and downgrade those connections before downgrading more sensitive connections. A service level downgrade may be temporary, for example until the congestion condition is relieved, or may be permanent for as long as the affected device is connected to the cell.
Another example of a congestion control mechanism is applying a handoff delay to one or more additional resource requests in accordance with respective resource priority values. The radio resource management algorithm may affect handoff delay by altering a handoff margin applied to handoff resource requests. A handoff margin is measured as the difference in signal strengths received at a requesting device from the source cell the requesting device is currently connected to and the target cell the handoff request is directed to. Typically, a minimum handoff margin must be met before a handoff resource request will be fulfilled by a target cell. If the target margin for a particular target cell is increased, it may take longer for the signal strengths between the source and target cells received at devices with existing connections in neighboring cells to reach the handoff margin, thus imposing a handoff delay before those devices make handoff resource requests to the target cell. By reducing the number of handoff resource requests received at a target cell, larger quantities of handoff resources may be available. Varying handoff margins may be assigned by the radio resource management algorithm in accordance with the resource priorities assigned by the algorithm, for example lower priority requests may be subjected to longer delays.
Another example of a congestion control mechanism is releasing a soft handoff connection resource. It is known that certain wireless interface technologies, for example UMTS, employ soft handoff techniques when a connection is handed off between neighboring cells. In a soft handoff scenario, a device may maintain its connection to its source cell, while it establishes one or more soft handoff connections to corresponding target cells prior to being handed off to one of those target cells. These soft handoff connections may be established and/or maintained even when a handoff is not imminent. The radio resource management protocol may release one or more soft handoff connections to its cell in order to make those handoff resources available for prioritized resource requests. Devices with the highest number of soft handoff connections may have their soft handoff connections released first. Alternatively, the radio resource management algorithm may release soft handoff connections from lower priority connections before soft handoff connections of higher priority connections are released.
If the cell provisioned on BTS 204 becomes congested, there may not be sufficient wireless resources available to fulfill additional wireless resource requests. For example, the emergency responder mobile device 214 is making a new resource request, depicted in the figure as a dotted line, to the cell provisioned on BTS 204. The radio resource management algorithm may assign a high resource priority value to the new resource request from the emergency responder mobile device 214. The radio resource management algorithm may determine that the mobile device 212 has a lower resource priority value assigned to its soft handoff connection to the cell provisioned on BTS 204. The radio resource management algorithm may release the soft handoff connection to the mobile device 212, thereby making those handoff resources available for fulfilling the new resource request of the emergency responder mobile device 214. It is to be noted that the techniques used to release soft handoff resources with respect to
Returning to
In an example configuration, the network communications device 300 comprises a processing portion 302, a memory portion 304, an input/output portion 306, and an optional user interface (UI) portion 308. It is emphasized that the block diagram depiction of network communications device 300 is exemplary and not intended to imply a specific implementation and/or configuration. The processing portion 302, memory portion 304, and input/output portion 306 are coupled together to allow communications therebetween. In various embodiments, the input/output portion 306 comprises one or more radio receivers, receivers, and/or transceivers of the network communications device 300, one or more wireline interfaces of the network communications device, or a combination thereof. The input/output portion 306 is capable of receiving and/or providing wireless communications between the network communications device and requesting devices, and of provisioning wireless radio resources to requesting devices in accordance with a radio resource management algorithm as described above. For example, the input/output portion 306 is capable of receiving a resource request from a requesting device, and of provisioning the requesting device with a quantity of wireless resources if the resource request is accepted and fulfilled, as described herein. The network communications device is also capable of sending and/or receiving communications from other network communications devices via the one or more wireline interfaces of the input/output portion 306. In an example embodiment, the input/output portion 306 is capable of receiving a communication from a network resource admission control (NRAC) containing a resource prioritization scheme for implementation by the radio resource management algorithm operating on the network communications device. In various configurations, the input/output portion 306 can receive and/or provide information via any appropriate means, such as, for example, optical means (e.g., infrared), electromagnetic means (e.g., RF, Wi-Fi (IEEE 802.11), WiMAX (IEEE 802.16), Bluetooth®, and the like), packet formatted data transmission protocols (e.g., TCP/IP, SONET, ATM, ISDN, Frame Relay, and the like), or a combination thereof.
The processing portion 302 may include any hardware and/or software necessary for operating and/or controlling the memory portion 304, the input/output portion 306, and/or the user interface (UI) portion 308. For example, the processing portion 302 may be individual digital logic components, one or more processors, one or more microprocessors, an application-specific integrated circuit (ASIC), and the like. The processing portion 302 may have its own memory such as random access memory (RAM), register memory, cache memory, and the like. The processing portion 302 may operate on computer-executable instructions. Computer-executable instructions may include computer-readable instructions, for example machine code, byte code, script language, runtime code, and the like. The computer-executable instructions for example, when executed by the processing portion 302, may cause the processing portion to perform a method of provisioning wireless radio resources to requesting devices in accordance with a radio resource management algorithm as described above. For example, the processing portion 302 is capable of prioritizing a resource request received by the network communications device by executing algorithm processes, such as evaluating functions to determine resource priority values, optimizing resource priority values, and arranging resource requests in a priority queue, as described above.
In a basic configuration, the network communications device 300 can include at least one memory portion 404. The memory portion can store any information utilized in conjunction with provisioning wireless radio resources to requesting devices in accordance with a radio resource management algorithm as described above. For example, the memory portion 304 is capable of storing information pertaining to factors used in evaluating functions to determine resource priority values, optimized resource priority values, resource priority values assigned to one or more resource requests and/or existing connections, and the like, as described above. Depending upon the exact configuration and type of the processor portion 302, the memory portion 304 can be volatile (such as some types of RAM), non-volatile (such as ROM, flash memory, etc.), or a combination thereof. The network communications device 300 can include additional storage (e.g., removable storage and/or non-removable storage) including, but not limited to, tape, flash memory, smart cards, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, universal serial bus (USB) compatible memory, or any other medium which can be used to store information and which can be accessed by the mobile communications device.
The network communications device 300 also can contain a user interface (UI) portion 308 for allowing a user (e.g., an administrator) to communicate with the network communications device. The UI portion is capable of rendering any information utilized in conjunction with provisioning wireless radio resources to requesting devices in accordance with a radio resource management algorithm as described above. For example, the UI portion may render graphical representations of available wireless handoff resources within a cell, a priority queue, and the like. The UI portion 308 can provide the ability to control and/or configure the network communications device, either locally or remotely via, for example, buttons, soft keys, voice actuated controls, a touch screen, visual cues (e.g., moving a hand in front of a camera integrated in the communications device (not shown)), or the like. The UI portion can provide visual information (e.g., via a display), audio information (e.g., via speaker), or a combination thereof. In various configurations, the UI portion 308 can comprise one or more displays, one or more touch screens, a keyboard, a speaker, a microphone, a camera, a motion detector, or any combination thereof. The UI portion 308 can comprise means for inputting biometric information, such as, for example, fingerprint information, retinal information, voice information, and/or facial characteristic information.
Generally, there can be a several cell sizes in a GSM network, referred to as macro, micro, pico, femto and umbrella cells. The coverage area of each cell is different in different environments. Macro cells can be regarded as cells in which the base station antenna is installed in a mast or a building above average roof top level. Micro cells are cells whose antenna height is under average roof top level. Micro-cells are typically used in urban areas. Pico cells are small cells having a diameter of a few dozen meters. Pico cells are used mainly indoors. Femto cells have the same size as pico cells, but a smaller transport capacity. Femto cells are used indoors, in residential or small business environments. On the other hand, umbrella cells are used to cover shadowed regions of smaller cells and fill in gaps in coverage between those cells.
An architecture of a typical GPRS network in which provisioning wireless radio resources to requesting devices in accordance with a radio resource management algorithm can be implemented is segmented into four groups: users, a radio access network, a core network, and an interconnect network. Users comprise a plurality of end users referred to as mobile subscribers. In an example embodiment, a mobile subscriber comprises a communications device (e.g., communications device 300). A radio access network comprises a plurality of BSSs, which include BTSs and BSCs. A core network may comprise a Mobile Switching Center (“MSC”), Service Control Point (“SCP”), gateway MSC, SGSN, Home Location Register (“HLR”), Authentication Center (“AuC”), Domain Name Server (“DNS”), and GGSN. An example interconnect network comprises a Public Switched Telephone Network (“PSTN”), Fixed-End System (“FES”) or Internet, firewall, and Corporate Network.
A mobile switching center can be connected to a large number of base station controllers. At an MSC, for instance, depending on the type of traffic, the traffic may be separated in that voice may be sent to a Public Switched Telephone Network (“PSTN”) through a Gateway MSC (“GMSC”), and/or data may be sent to an SGSN, which then sends the data traffic to a GGSN for further forwarding.
When an MSC receives call traffic, for example from a BSC, it sends a query to a database hosted by an SCP. The SCP processes the request and issues a response to the MSC so that it may continue call processing as appropriate.
The HLR is a centralized database for users to register to the GPRS network. The HLR stores static information about the subscribers such as the International Mobile Subscriber Identity (“IMSI”), subscribed services, and a key for authenticating the subscriber. The HLR also stores dynamic subscriber information such as the current location of the mobile subscriber. Associated with the HLR is the AuC. The AuC is a database that contains the algorithms for authenticating subscribers and includes the associated keys for encryption to safeguard the user input for authentication.
In the following, depending on context, the term “mobile subscriber” sometimes refers to the end user and sometimes to the actual portable device, such as a mobile device, used by an end user of the mobile cellular service. When a mobile subscriber turns on his or her mobile device, the mobile device goes through an attach process by which the mobile device attaches to an SGSN of the GPRS network. When a mobile subscriber initiates the attach process by turning on the network capabilities of the mobile device, an attach request is sent by the mobile subscriber to an SGSN. The SGSN queries another SGSN, to which the mobile subscriber was attached before, for the identity of the mobile subscriber. Upon receiving the identity of the mobile subscriber from the other SGSN, the SGSN requests more information from the mobile subscriber. This information is used to authenticate the mobile subscriber to the SGSN by the HLR. Once verified, the SGSN sends a location update to the HLR indicating the change of location to the new SGSN. The HLR notifies the old SGSN, to which mobile subscriber was attached before, to cancel the location process for the mobile subscriber. The HLR then notifies the SGSN that the location update has been performed. At this time, the SGSN sends an Attach Accept message to the mobile subscriber, which in turn sends an Attach Complete message to the SGSN.
After attaching itself with the network, the mobile subscriber then goes through the authentication process. In the authentication process, the SGSN sends the authentication information to the HLR, which sends information back to the SGSN based on the user profile that was part of the user's initial setup. The SGSN then sends a request for authentication and ciphering to the mobile subscriber. The mobile subscriber uses an algorithm to send the user identification (ID) and password to the SGSN. The SGSN uses the same algorithm and compares the result. If a match occurs, the SGSN authenticates the mobile subscriber.
Next, the mobile subscriber establishes a user session with the destination network, a corporate network, by going through a Packet Data Protocol (“PDP”) activation process. Briefly, in the process, the mobile subscriber requests access to the Access Point Name (“APN”), for example, UPS.com, and the SGSN receives the activation request from the mobile subscriber. The SGSN then initiates a Domain Name Service (“DNS”) query to learn which GGSN node has access to the UPS.com APN. The DNS query is sent to a DNS server within the core network, which is provisioned to map to one or more GGSN nodes in the core network. Based on the APN, the mapped GGSN can access the requested corporate network. The SGSN then sends to the GGSN a Create Packet Data Protocol (“PDP”) Context Request message that contains necessary information. The GGSN sends a Create PDP Context Response message to the SGSN, which then sends an Activate PDP Context Accept message to the mobile subscriber.
Once activated, data packets of the call made by the mobile subscriber can then go through the radio access network, the core network, and the interconnect network, in a particular fixed-end system or Internet and firewall, to reach the corporate network.
An example GSM/GPRS/IP multimedia network architecture within which provisioning wireless radio resources to requesting devices in accordance with a radio resource management algorithm can be implemented includes a GSM core network, a GPRS network and an IP multimedia network. The GSM core network includes a Mobile Station (MS), at least one Base Transceiver Station (BTS) and a Base Station Controller (BSC). The MS is physical equipment or Mobile Equipment (ME), such as a mobile phone or a laptop computer that is used by mobile subscribers, with a Subscriber Identity Module (SIM) or a Universal Integrated Circuit Card (UICC). The SIM or UICC includes an International Mobile Subscriber Identity (IMSI), which is a unique identifier of a subscriber. The BTS is physical equipment, such as a radio tower, that enables a radio interface to communicate with the MS. Each BTS may serve more than one MS. The BSC manages radio resources, including the BTS. The BSC may be connected to several BTSs. The BSC and BTS components, in combination, are generally referred to as a base station subsystem (BSS) or radio access network (RAN).
The GSM core network also includes a Mobile Switching Center (MSC), a Gateway Mobile Switching Center (GMSC), a Home Location Register (HLR), a Visitor Location Register (VLR), an Authentication Center (AuC), and an Equipment Identity Register (EIR). The MSC performs a switching function for the network. The MSC also performs other functions, such as registration, authentication, location updating, handovers, and call routing. The GMSC provides a gateway between the GSM network and other networks, such as an Integrated Services Digital Network (ISDN) or Public Switched Telephone Networks (PSTNs). Thus, the GMSC provides interworking functionality with external networks.
The HLR is a database that contains administrative information regarding each subscriber registered in a corresponding GSM network. The HLR also contains the current location of each MS. The VLR is a database that contains selected administrative information from the HLR. The VLR contains information necessary for call control and provision of subscribed services for each MS currently located in a geographical area controlled by the VLR. The HLR and the VLR, together with the MSC, provide the call routing and roaming capabilities of GSM. The AuC provides the parameters needed for authentication and encryption functions. Such parameters allow verification of a subscriber's identity. The EIR stores security-sensitive information about the mobile equipment.
A Short Message Service Center (SMSC) allows one-to-one Short Message Service (SMS) messages to be sent to/from the MS. A Push Proxy Gateway (PPG) is used to “push” (i.e., send without a synchronous request) content to the MS. The PPG acts as a proxy between wired and wireless networks to facilitate pushing of data to the MS. A Short Message Peer to Peer (SMPP) protocol router is provided to convert SMS-based SMPP messages to cell broadcast messages. SMPP is a protocol for exchanging SMS messages between SMS peer entities such as short message service centers. The SMPP protocol is often used to allow third parties, e.g., content suppliers such as news organizations, to submit bulk messages.
To gain access to GSM services, such as speech, data, and short message service (SMS), the MS first registers with the network to indicate its current location by performing a location update and IMSI attach procedure. The MS sends a location update including its current location information to the MSC/VLR, via the BTS and the BSC. The location information is then sent to the MS's HLR. The HLR is updated with the location information received from the MSC/VLR. The location update also is performed when the MS moves to a new location area. Typically, the location update is periodically performed to update the database as location updating events occur.
The GPRS network is logically implemented on the GSM core network architecture by introducing two packet-switching network nodes, a serving GPRS support node (SGSN), a cell broadcast and a gateway GPRS support node (GGSN). The SGSN is at the same hierarchical level as the MSC in the GSM network. The SGSN controls the connection between the GPRS network and the MS. The SGSN also keeps track of individual MS's locations and security functions and access controls.
A Cell Broadcast Center (CBC) communicates cell broadcast messages that are typically delivered to multiple users in a specified area. Cell Broadcast is one-to-many geographically focused service. It enables messages to be communicated to multiple mobile phone customers who are located within a given part of its network coverage area at the time the message is broadcast.
The GGSN provides a gateway between the GPRS network and a public packet network (PDN) or other IP networks. That is, the GGSN provides interworking functionality with external networks, and sets up a logical link to the MS through the SGSN. When packet-switched data leaves the GPRS network, it is transferred to an external TCP-IP network, such as an X.25 network or the Internet. In order to access GPRS services, the MS first attaches itself to the GPRS network by performing an attach procedure. The MS then activates a packet data protocol (PDP) context, thus activating a packet communication session between the MS, the SGSN, and the GGSN.
In a GSM/GPRS network, GPRS services and GSM services can be used in parallel. The MS can operate in one of three classes: class A, class B, and class C. A class A MS can attach to the network for both GPRS services and GSM services simultaneously. A class A MS also supports simultaneous operation of GPRS services and GSM services. For example, class A mobiles can receive GSM voice/data/SMS calls and GPRS data calls at the same time.
A class B MS can attach to the network for both GPRS services and GSM services simultaneously. However, a class B MS does not support simultaneous operation of the GPRS services and GSM services. That is, a class B MS can only use one of the two services at a given time.
A class C MS can attach for only one of the GPRS services and GSM services at a time. Simultaneous attachment and operation of GPRS services and GSM services is not possible with a class C MS.
A GPRS network can be designed to operate in three network operation modes (NOM1, NOM2 and NOM3). A network operation mode of a GPRS network is indicated by a parameter in system information messages transmitted within a cell. The system information messages dictates a MS where to listen for paging messages and how to signal towards the network. The network operation mode represents the capabilities of the GPRS network. In a NOM1 network, a MS can receive pages from a circuit switched domain (voice call) when engaged in a data call. The MS can suspend the data call or take both simultaneously, depending on the ability of the MS. In a NOM2 network, a MS may not receive pages from a circuit switched domain when engaged in a data call, since the MS is receiving data and is not listening to a paging channel. In a NOM3 network, a MS can monitor pages for a circuit switched network while receiving data and vise versa.
The IP multimedia network was introduced with 3GPP Release 5, and includes an IP multimedia subsystem (IMS) to provide rich multimedia services to end users. A representative set of the network entities within the IMS are a call/session control function (CSCF), a media gateway control function (MGCF), a media gateway (MGW), and a master subscriber database, called a home subscriber server (HSS). The HSS may be common to the GSM network, the GPRS network as well as the IP multimedia network.
The IP multimedia system is built around the call/session control function, of which there are three types: an interrogating CSCF (I-CSCF), a proxy CSCF (P-CSCF), and a serving CSCF (S-CSCF). The P-CSCF is the MS's first point of contact with the IMS. The P-CSCF forwards session initiation protocol (SIP) messages received from the MS to an SIP server in a home network (and vice versa) of the MS. The P-CSCF may also modify an outgoing request according to a set of rules defined by the network operator (for example, address analysis and potential modification).
The I-CSCF, forms an entrance to a home network and hides the inner topology of the home network from other networks and provides flexibility for selecting an S-CSCF. The I-CSCF may contact a subscriber location function (SLF) to determine which HSS to use for the particular subscriber, if multiple HSSs are present. The S-CSCF performs the session control services for the MS. This includes routing originating sessions to external networks and routing terminating sessions to visited networks. The S-CSCF also decides whether an application server (AS) is required to receive information on an incoming SIP session request to ensure appropriate service handling. This decision is based on information received from the HSS (or other sources, such as an application server). The AS also communicates to a location server (e.g., a Gateway Mobile Location Center (GMLC)) that provides a position (e.g., latitude/longitude coordinates) of the MS.
The HSS contains a subscriber profile and keeps track of which core network node is currently handling the subscriber. It also supports subscriber authentication and authorization functions (AAA). In networks with more than one HSS, a subscriber location function provides information on the HSS that contains the profile of a given subscriber.
The MGCF provides interworking functionality between SIP session control signaling from the IMS and ISUP/BICC call control signaling from the external GSTN networks. It also controls the media gateway (MGW) that provides user-plane interworking functionality (e.g., converting between AMR- and PCM-coded voice). The MGW also communicates with other IP multimedia networks.
Push to Talk over Cellular (PoC) capable mobile phones register with the wireless network when the phones are in a predefined area (e.g., job site, etc.). When the mobile phones leave the area, they register with the network in their new location as being outside the predefined area. This registration, however, does not indicate the actual physical location of the mobile phones outside the predefined area.
The various functions and/or features of the radio resource management algorithm described herein can be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the methods and apparatuses for prioritizing requests to network resources in accordance with a radio resource management algorithm can be implemented, or certain aspects or portions thereof, can take the form of program code (i.e., instructions) embodied in tangible storage media, such as floppy diskettes, CD-ROMs, hard drives, or any other machine-readable storage medium (computer-readable storage medium), wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for prioritizing requests to network resources. In the case of program code execution on programmable computers, the computing device will generally include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. The program(s) can be implemented in assembly or machine language, if desired. The language can be a compiled or interpreted language, and combined with hardware implementations.
The methods and apparatuses for prioritizing requests to network resources in accordance with a radio resource management algorithm can also can be practiced via communications embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission, wherein, when the program code is received and loaded into and executed by a machine, such as an EPROM, a gate array, a programmable logic device (PLD), a client computer, or the like, the machine becomes an apparatus for prioritizing requests to network resources. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates to invoke the functionality of prioritizing requests to network resources in accordance with a radio resource management algorithm. Additionally, any storage techniques used in connection with prioritizing requests to network resources in accordance with a radio resource management algorithm can invariably be a combination of hardware and software.
While prioritizing requests to network resources in accordance with a radio resource management algorithm have been described in connection with the various embodiments of the various figures, it is to be understood that other similar embodiments can be used or modifications and additions can be made to the described embodiments for prioritizing requests to network resources in accordance with a radio resource management algorithm without deviating therefrom. For example, one skilled in the art will recognize that prioritizing requests to network resources in accordance with a resource management algorithm as described in the present application may apply to any environment, whether wired or wireless, and may be applied to any number of such devices connected via a communications network and interacting across the network. Therefore, prioritizing requests to network resources in accordance with a radio resource management algorithm should not be limited to any single embodiment, but rather should be construed in breadth and scope in accordance with the appended claims.
