System and method for virtual radio cell
1. A radio access network node operable within a shared radio access network, the radio access network including at least one radio cell and providing access to multiple mobile networks, comprising:
- a. a radio cell comprising a physical node configured to support a plurality of virtual nodes, the radio cell configured to broadcast data corresponding to a radio access service provided via the radio cell;
b. wherein the radio cell is further configured to broadcast a plurality of network identifiers of respective multiple mobile networks corresponding to at least the plurality of virtual nodes; and
c. wherein the radio cell is further configured to broadcast a mobile network specific parameter applicable only for accessing a specific mobile network, the accessing by user equipment associated with the specific mobile network, wherein the mobile network specific parameter includes at least one of the group consisting of;
a tracking area code, a cell identifier, and a cell barred indication.
In particular, systems and methods according to present principles configure physical eNodeB to have multiple virtual eNodeBs, where each virtual eNodeBs corresponds to a particular PLMN. Thus, each PLMN has its own virtual eNodeB which is hosted on a common shared physical eNodeB.
|Method and apparatus for informing a radio access network of a selected core network from user equipment in a network sharing system|
Patent #US 20060183502A1
Current AssigneeSamsung Electronics Co. Ltd.
Sponsoring EntitySamsung Electronics Co. Ltd.
|FLEXIBLE NETWORK SHARING|
Patent #US 20130303114A1
Current AssigneeInterDigital Patent Holdings Inc.
Sponsoring EntityInterDigital Patent Holdings Inc.
|APPARATUS AND METHOD FOR SUPPORTING HANDOVER TO CSG CELL OR HYBRID CELL|
Patent #US 20150072686A1
Current AssigneeSamsung Electronics Co. Ltd.
Sponsoring EntitySamsung Electronics Co. Ltd.
|Long term evolution architecture and mobility|
Patent #US 8,982,841 B2
Current AssigneeCorning Optical Communications LLC
Sponsoring EntitySpiderCloud Wireless Inc.
|NODE SELECTION IN VIRTUAL EVOLVED PACKET CORE|
Patent #US 20150109995A1
Current AssigneeCisco Technology Incorporated
Sponsoring EntityCisco Technology Incorporated
|FRACTIONAL FREQUENCY REUSE SCHEMES ASSIGNED TO RADIO NODES IN AN LTE NETWORK|
Patent #US 20150131537A1
Current AssigneeCorning Optical Communications LLC
Sponsoring EntityCorning Optical Communications LLC
|Hybrid joint processing for use in a radio access network|
Patent #US 9,356,764 B2
Current AssigneeCorning Optical Communications LLC
Sponsoring EntitySpiderCloud Wireless Inc.
|Enhanced Features for a Gateway Coordinating Multiple Small Cell Radio Access Networks|
Patent #US 20160262063A1
Current AssigneeCorning Optical Communications LLC
Sponsoring EntityCorning Optical Communications LLC
- 1. A radio access network node operable within a shared radio access network, the radio access network including at least one radio cell and providing access to multiple mobile networks, comprising:
a. a radio cell comprising a physical node configured to support a plurality of virtual nodes, the radio cell configured to broadcast data corresponding to a radio access service provided via the radio cell; b. wherein the radio cell is further configured to broadcast a plurality of network identifiers of respective multiple mobile networks corresponding to at least the plurality of virtual nodes; and c. wherein the radio cell is further configured to broadcast a mobile network specific parameter applicable only for accessing a specific mobile network, the accessing by user equipment associated with the specific mobile network, wherein the mobile network specific parameter includes at least one of the group consisting of;
a tracking area code, a cell identifier, and a cell barred indication.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 11. A mobile device operable to communicate with a specific mobile network via a shared radio access network, the mobile device programmed to perform the following steps:
a. receiving broadcast information from a radio cell belonging to a shared radio access network; b. detecting a network identifier and mobile network specific broadcast parameters within the broadcast information associated with a selected mobile network, wherein the mobile network specific broadcast parameters include one or more of the group consisting of;
a tracking area code, a cell identifier, and a cell barred indication; and
c. applying the detected mobile network specific broadcast parameters, whereby communication is enabled with the selected mobile network via the shared radio access network.
- View Dependent Claims (12, 13, 14, 15, 16, 17)
The invention relates to wireless communications and particularly to wireless communications in shared radio networks.
Operators of mobile systems, such as Universal Mobile Telecommunications Systems (UMTS) and its offspring including LTE (Long Term Evolution) and LTE-Advanced, are increasingly relying on wireless small cell radio access networks (RANs) in order to deploy indoor voice and data services at enterprises and other premises. Such small cell RANs typically utilize multiple-access technologies capable of supporting communications with multiple users using radio frequency (RF) signals and sharing available system resources such as bandwidth and transmit power. While such small cell RANs operate satisfactorily in many applications, there exists a need for further improvements in small cell RAN technologies, and such is particularly true as consumers desire more and more data, placing greater and more difficult-to-meet requirements on such cells.
In some implementations, operators can share common radio resources, according to identified RAN sharing scenarios. Such RAN sharing is supported in 3GPP standards (MOCN, GWCN). In LTE, RAN sharing implies the sharing of eNodeBs. That is, one eNodeB can belong to multiple public land mobile networks (PLMNs) by broadcasting multiple PLMN IDs. However, each eNodeB has only a single eNodeB ID, TAC, CSG indication, and CSG ID. In this case, a primary PLMN operator (usually the operator who deploys the network) assigns or provisions these parameters to the eNodeB, and if the eNodeB belongs to multiple PLMNs, the other PLMNs have to accommodate the same parameters. This is problematic as coordination among PLMN operators is required to identify parameters that are suitable and non-conflicting across all PLMNs.
This Background is provided to introduce a brief context for the Summary and Detailed Description that follow. This Background is not intended to be an aid in determining the scope of the claimed subject matter nor be viewed as limiting the claimed subject matter to implementations that solve any or all of the disadvantages or problems presented above.
Systems and methods according to present principles meet the needs of the above in several ways.
In particular, systems and methods according to present principles configure one or more physical eNodeBs to have one or more virtual eNodeBs, where each virtual eNodeBs corresponds to a particular PLMN or group of PLMNs. Thus, each PLMN can have its own virtual eNodeB which is hosted on a common shared physical eNodeB. Correspondingly, virtual eNBs or associated parameter sets may be specific to a particular PLMN or a group thereof.
Note that PLMN is just used as an example of a core network using the shared RAN. In addition to PLMN, the core network may be a Neutral Host Network (NHN) or another type of communication network able to utilize a shared RAN.
To implement such a system, the System Information Broadcast by the eNodeB can be extended so that at least some separate identifiers can be broadcast for each supported PLMN. It is noted that in a particular implementation, MulteFire radio technology (which operates a modified version of LTE radio technology entirely in the unlicensed or other shared spectrum) has already a newly defined System Information Broadcast message, replacing the LTE SIB1 and SIB2, so such extension might be particularly convenient and easy to accommodate in such implementations.
In one aspect, the invention is directed towards a radio access network operable as a shared radio access network, the radio access network including at least one radio cell and providing access to multiple mobile networks, including: a radio cell, configured to broadcast data corresponding to a radio access service provided via the radio cell; where the radio cell is further configured to broadcast a plurality of identifiers of respective multiple mobile networks; and where the radio cell is further configured to broadcast mobile network specific information applicable only for accessing a specific mobile network, the accessing by user equipment associated with the specific mobile network.
Implementations of the invention may include one or more of the following.
The radio cell may support access technologies corresponding to one or more of the group consisting of: MulteFire, LTE, 5G. The mobile network may be selected from one or more of the group consisting of: PLMNs, NHNs. The identifiers may correspond to PLMN identifiers. The broadcast of mobile network specific information may be such that the radio cell is enabled to support multiple virtual radio cells, each associated with at least one of the multiple mobile networks. The mobile network specific information may include mobile network specific identifiers associated with the radio cell. The mobile network specific information may include at least one of the group consisting of: tracking area code, cell identifier, closed subscriber group indication, closed subscriber group identifier, and cell barred indication. A radio access network node operating the radio cell may be configured to apply the mobile network specific information in communications with each of the multiple mobile networks. The radio cell may be a member of a plurality of radio cells controlled by an eNodeB, where first and second radio cells each receive respective first and second sets of lists of network specific information to service multiple mobile networks associated therewith, and the first and second sets are different. The first and second sets may be associated with different PLMNs.
In another aspect, the invention is directed towards a non-transitory computer readable medium, including instructions for causing the radio access network to perform the steps of broadcasting data, broadcasting the plurality of identifiers, and broadcasting the mobile network specific information.
In another aspect, the invention is directed towards a mobile device operable to communicate with a specific mobile network via a shared radio access network, the mobile device programmed to perform the following steps: receiving broadcast information from a radio cell belonging to a shared radio access network; detecting mobile network specific broadcast information associated with a selected mobile network; and applying the detected mobile network specific broadcast information, whereby communication is enabled with the selected mobile network via the shared radio access network.
Implementations of the invention may include one or more of the following.
The applying may include configuring the mobile device according to the detected mobile network specific broadcast information. The radio cell may support access technologies corresponding to one or more of the group consisting of: MulteFire, LTE, 5G. The mobile network may be selected from one or more of the group consisting of: PLMNs, NHNs. The mobile network specific broadcast information may include mobile network specific identifiers associated with the radio cell. The mobile network specific broadcast information may include at least one of the group consisting of: tracking area code, cell identifier, closed subscriber group indication, closed subscriber group identifier, and cell barred indication. A radio access network node operating the radio cell may be configured to apply the mobile network specific broadcast information in communications with multiple mobile networks.
Advantages of the invention may include, in certain embodiments, one or more of the following. PLMNs and other core networks no longer need to coordinate required parameters. Systems and methods according to present principles simplify multi-mobile network operator provisioning for physically-shared eNodeBs. Other benefits of certain implementations may include, e.g. elimination of the requirement of coordinating among multiple operators in the context of RAN sharing, or significantly reduced coordination. Systems and methods according to present principles generally have no impact to the EPC, nor is there an impact to UE beyond the “smart” decoding of the new system information. Other benefits include that the secondary PLMNs can provision the shared eNodeBS almost as if they were their own. There is additional broadcast overhead, but only when PLMN-specific information is in use. In addition, systems and methods according to present principles generally need only require additional logic in the eNodeB for S1 handling and in the UE for system information decoding.
Using systems and methods according to present principles, system-wide impacts from implementing such technology are minimal. The base station or eNodeB need only select and connect to the appropriate core network based on the UE connecting to it. For each core network, the eNodeB applies the information relevant for that core network.
Other advantages will be understood from the description that follows, including the figures and claims.
This Summary is provided to introduce a selection of concepts in a simplified form. The concepts are further described in the Detailed Description section. Elements or steps other than those described in this Summary are possible, and no element or step is necessarily required. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended for use as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
Like reference numerals refer to like elements throughout. Elements are not to scale unless otherwise noted.
Operators of mobile systems, such as Universal Mobile Telecommunications Systems (UMTS) and its offspring including LTE (Long Term Evolution) and LTE-Advanced, are increasingly relying on wireless small cell radio access networks (RANs) in order to deploy indoor (as well as dense outdoor) voice and data services to enterprises and other premises or locations. Such small cell RANs typically utilize multiple-access technologies capable of supporting communications with multiple users using radio frequency (RF) signals and sharing available system resources such as bandwidth and transmit power.
One type of RAN architecture that is currently deployed includes a network of radio nodes connected to a centralized access controller or aggregation node. In this type of architecture, the eNodeB, NodeB, or base station functionalities are distributed between the radio nodes and the centralized access controller. One example of such a controller or node is the Services Node available from Spidercloud Wireless, Inc. The centralized Services Node provides a number of advantages that help meet stringent key performance indicator (KPI) requirements. It also may have dedicated hardware that is used to provide frequency synchronization between radio nodes in order to facilitate UMTS and LTE airlink performance.
The size of the enterprise 105 and the number of cells deployed in the small cell RAN 110 may vary. In typical implementations, the enterprise 105 can be from 50,000 to 500,000 square feet and encompass multiple floors and the small cell RAN 110 may support hundreds to thousands of users using mobile communication platforms such as mobile phones, smartphones, tablet computing devices, and the like (referred to as “user equipment” (UE) and indicated by reference numerals 1251-125N in
The small cell RAN 110 includes an access controller 130 that manages and controls the radio nodes 115. The radio nodes 115 are coupled to the access controller 130 over a direct or local area network (LAN) connection (not shown in
The environment 100 also generally includes other Evolved Node B (eNodeB) base stations, or “macrocells”, as representatively indicated by reference numeral 155 in
As noted above, one implementation of operators can share common radio resources, according to identified sharing scenarios. For example, an eNodeB can be shared by multiple LTE operators and the same is termed “Multi-Operator Core Network” (MOCN). GWCN approaches are also employed, and as such technologies allow base stations to provide functionality to more than one network.
In addition, there is currently significant discussion around the use of unlicensed or other shared spectrum. Unlicensed or shared spectrum is not specific to any one operator but is available to all or to a given deployment, and thus is well-suited to the use of RAN sharing.
Various technologies are being developed for such applications within unlicensed spectrum, e.g., LTE-U and LAA, which augment the licensed spectrum with carriers in the unlicensed spectrum. MulteFire is another example, which operates a modified version of LTE fully in the unlicensed or other shared spectrum. This technology, proposed by the MulteFire Alliance, enhances LTE such that it can operate in the unlicensed or shared spectrum, and can conform to the special requirements of operating in such spectrum.
It is expected that many MulteFire and other unlicensed or shared spectrum deployments will involve small cells, due to the suitability of the frequency range, transmission power limits, and other reasons. It is also expected that such will commonly be deployed in venues in which there is demand for serving subscribers from multiple operators. One approach to address the issues discussed above is with traditional RAN sharing. But such has associated the problems described above. Another method is termed the “neutral host network method”, which is generally more tailored for enterprise-owned solutions, and can provide neutral host roaming or offload functionality to multiple mobile operators and other service providers.
In systems and methods according to present principles though, and referring to
For example, a shared cell may broadcast just one cell-ID that applies across multiple PLMNs, while broadcasting PLMN specific Tracking Area Codes (TAC). Some PLMNs may prefer to have the cell broadcast PLMN-specific Closed Subscriber Group (CSG) related information, such as CSG Indication or CSG Identity. Some cells may be configured to have multiple cell IDs, etc. Which parameters to share across the PLMNs, and which specific value to use, depends on the adopted system information broadcast specifications and can be different in different deployments.
The mobile devices that connect to the cell do so for connecting to their respective operator, and thus they detect and follow are configured with the broadcasted parameters that apply to their network, potentially ignoring the other broadcasted parameters associated with other network(s). Similarly, the base station has data about which UE pertains to which network, so whenever the base station communicates with the appertaining network, it uses the appropriate parameter(s).
To implement the above, the System Information Broadcast, constituted by system information blocks, can be extended so that separate identifiers can be broadcasted for each supported PLMN. As noted above, in a particular implementation, MulteFire radio technology has a newlydefined System Information Broadcast message, replacing LTE SIB1 and SIB2, so such extension might be particularly convenient and easy to accommodate in such implementations.
In current LTE, the System Information Broadcast includes the following components. (LTE SIB1):
PLMN Identity List: Up to six PLMN identities can be specified, which is employed to accommodate prior RAN sharing. As described such prior RAN sharing required coordination among PLMN operators, among other deficiencies. Such techniques did not include the broadcast of other parameters that allow RAN sharing without such specific required PLMN coordination.
Other components include:
Tracking Area Code: ranging from 0 to 65535 (16 bits)
Cell ID: containing cell identity and has a length of 28 bits
CSG Indication: indicating whether the cell is a closed subscriber group (CSG) cell or not (1 bit). CSG ID: (optional)—contains the CSG identity (27 bits)
The proposed System Information Broadcast (see element 18 of
The new SIB elements may include one or more of:
List of PLMN identities: For example, in one implementation, up to six PLMN identities can be specified, which can constitute a primary PLMN ID and up to five secondary PLMN IDS. The UE performs PLMN selection and selects one of the PLMN-IDS as the “selected PLMN-ID”. The UE then indicates the “selected PLMN-ID” to the eNodeB when setting up the RRC connection. One PLMN-ID may be the NHAMI, indicating NHN support.
List of Tracking Area Codes (TAC): ranging from 0 to 65535 (16 bits). A TAC is generally mandatory for the primary PLMN. Secondary PLMNs can have their own TAC or can reuse the TAC of the primary PLMN. The eNodeB broadcasts up to, e.g., six TACs. The UE detects the TAC value that is associated with its “selected PLMN-ID”. The eNodeB forms the TAI value which it sends towards the MME over S1-MME based on the UE'"'"'s selected PLMN-ID and the TAC value associated with the selected PLMN-ID. PLMN-specific TACs may be a particularly significant benefit, as it removes the need for TAC value coordination between PLMNs.
List of Cell IDs: containing eNodeB identity and has a length of 28 bits. Cell ID is generally mandatory for the primary PLMN. Secondary PLMNs can have their own cell ID or can reuse the cell ID of the primary PLMN. In more detail, regarding eNodeB and cell global ID (ECGI), the eNodeB may be associated with up to, e.g., six eNodeB IDs corresponding to six respective PLMN-IDs. Each cell of the eNodeB broadcasts up to six cell IDs corresponding to the six eNodeB IDs (each 20 bits) combined with a cell identifier (8 bits). The UE detects the cell ID value that is associated with its selected PLMN-ID. The eNodeB forms the EUTRAN cell global ID (ECGI) which is sent towards the MME over S1-MME based on the UE'"'"'s selected PLMN-ID and the eNodeB ID value associated with the selected PLMN-ID. Having separate cell IDs simplifies shared eNodeB provisioning. The use of the primary PLMN ECGI is possible across multiple PLMNs, so there is not a strict need for PLMN specific cell IDs. However, use of such separate IDs simplifies shared eNodeB provisioning for secondary PLMNs.
List of CSG Indications: This list indicates whether the cell is a CSG cell or not (1 bit). A CSG indication is mandatory for the primary PLMN, and secondary PLMNs can have their own CSG indication or can reuse the CSG indication of the primary PLMN. List of CSG IDs: (conditional)—This list contains the CSG identity (27 bits). This identity is present for PLMNs for which the CSG indication was set.
Regarding CSG, the eNodeB broadcasts up to six CSG indications, corresponding to six PLMN-IDs. In the same way, the eNodeB broadcasts up to six CSG-IDs corresponding to the six potential PLMN—IDs. The UE detects the values that are associated with its selected PLMN-ID. The eNodeB transmits to the MME about CSG—ID according to the CSG—ID associated with the selected PLMN-ID. Systems and methods according to present principles thus remove the need to coordinate CSG service and CSG identity values between PLMNs, and such separation may prove particularly useful in cases where only one PLMN provides CSG service in a given shared RAN.
The System Information Block should generally include the primary PLMN cell access information, e.g., cell ID, TAC, CSG indication, and CSG ID. It may optionally include separate cell access information IEs for secondary PLMNs. These also may include, e.g., cell ID, TAC, CSG indication, and CSG ID. If a specific separate cell access information IE is not present for the selected PLMN, then the value for the corresponding primary PLMN may be assumed to apply. Other parameters may also be allowed to be PLMN-specific, e.g., “cell reserved for operator use”, “cell barred”, and so on. The UE ignores cell access information IE'"'"'s that do not apply to its selected PLMN.
Thus, revising the System Information Block allows separate TACs, cell IDs, and/or CSG information for each PLMN. Each UE uses, corresponding to its selected PLMN-ID, a TAC, cell ID, and CSG. For S1-MME, the eNodeB inserts correct ECGI, TAI, and CSG values based on the selected PLMN.
Each PLMN provisions the network identification parameters for its own eNodeBs, e.g., PLMN-ID, TAC, eNodeB-ID, CSG-Indicator, CSG-ID, and so on. The shared physical eNodeB compiles the various virtual eNodeB information for the system information broadcast. The shared physical eNodeB, together with the associated O&M system, further sets other radio-related parameters that are common across all virtual eNodeBs, these can include for example, EARFCN, bandwidth, PCI, etc.
Gateway Coordinating Multiple Small Cell Radio Access Networks
As noted above, each eNodeB can have multiple core networks associated with it. In addition, using technology described below, in connection with
In a particular implementation, the services node SN resides not at the particular enterprise but at a data center. From there it can be connected to multiple small enterprises where individual cells are broadcasting into those enterprises. In such implementations, it is possible that only some of the cells, and thus some of the enterprises, are covered by a particular PLMN, e.g., AT&T or Verizon. But others are covered by different PLMNs, e.g., T-Mobile and Sprint. Thus it is possible that, in an eNodeB as described above, where multiple virtual eNodeBs are employed, the lists described above could differ. For example, the lists described above, e.g., of PLMN identities, tracking area codes, cell IDs, CSG indications, and CSG IDs, may be different from cell to cell.
In accordance with one aspect of the subject matter described herein, a method of coordinating a plurality of radio access networks (RANs) includes aggregating, with a gateway, communications interfaces between a plurality of RANs and a packet core network through the gateway. A plurality of radio cells or nodes (RNs) in each of the RANs is communicatively coupled to the gateway and to user equipment (UE) devices associated with the RNs in each of the RANs. The gateway also controls and coordinates mobility of the UE devices within and among the RANs. In addition, the gateway acts as a virtual enhanced NodeB (eNodeB) to the packet core network, thereby hiding the aggregated communications interfaces from the packet core network.
In accordance with another aspect of the subject matter described herein, a gateway through which a plurality of RANs communicates with a packet core network includes a plurality of access controller modules to which as least one RAN is assigned, a core network aggregator module, a mobility anchor module, and a cluster manager module. Each of the access controller modules is configured to control the respective RAN assigned thereto. The core network aggregator module is configured as a single interface for all communications between the plurality of access controller modules and the packet core network. All data plane traffic between UEs attached to one of the RANs and the packet core network terminates at the mobility anchor module. The cluster manager module assigns RNs to the access controller modules and transfers RN assignments from one access controller module to a different access controller module under specified circumstances.
A centralized access controller or aggregation node may be implemented as an enterprise premise-based controller element that coordinates a group of radio cells or nodes (RNs). In an LTE embodiment, the access controller functions as a local, premise-based gateway that anchors and aggregates a group of LTE RNs. As previously mentioned, one particular example of such an access controller is the Spidercloud Services Node. Details concerning the Spidercloud Services Node may be found in U.S. Pat. No. 8,982,841, which is hereby incorporated by reference in its entirety.
The use of the Spidercloud Services Node achieves a number of advantages. For instance, by presenting a services node and an entire group of RNs controlled by the SN as a single virtual evolved Node B (eNodeB) to the core network, the complexity associated with aggregating and controlling a large number of RNs (performed by the services node) is hidden from the Evolved Packet Core (EPC). Hiding such complexity is particularly important as the number of small cells is likely to significantly exceed the number of LTE macrocellular eNodeB'"'"'s, which drives the dimensioning of EPC equipment pools. Second, mobility between the individual RNs controlled by an SN is completely handled at a local enterprise gateway level, thus significantly reducing mobility-related signaling from impacting the MME pool in the EPC.
While the advantages of having a centralized access controller or aggregation node such as the Spidercloud Services Node have proven to be important, it is generally only well-suited for certain types of deployment. At the low end of the pyramid, deployments that require only a handful of radio nodes may not justify the additional cost incurred by installing a services node in the enterprise. At the high end of the pyramid, deployments that require thousands of radio nodes cannot be serviced because of scaling limitations in the current E-RAN software. However, as the number of small cells increases exponentially in the future, it may be advantageous to provide a scalable solution to deploy and manage those small cell systems with reduced capital and operating expenses.
To address this problem, an E-RAN gateway architecture is shown herein which can be scaled to support all sizes of deployments, either within the enterprise, inside the operator'"'"'s network, or in the cloud.
Moreover, virtualization is seen as an important trend in the telecommunications industry with large mobile operators committing to transform network functions running on dedicated and proprietary hardware to commercial off the shelf equipment running virtualized network functions. Accordingly, in some implementations the gateway architecture described herein may reside on a virtual machine platform, thus eliminating the need for specialized hardware.
As previously mentioned, the access controller shown above may be the Spidercloud Services Node, available from Spidercloud Wireless, Inc.
As mentioned above, an access controller is generally suitable for a small cell RAN 110 that includes anywhere from several (e.g., 8) cells 120 up to about 100 or so cells 120. RANs that include fewer than several cells 120 are typically too small to make the cost of the access controller economical. Likewise, RANs that include more than about 100 cells can be difficult to coordinate with a single access controller.
One way to address those environments in which the use of an access controller is impractical, either because it includes too few or too many cells, is to move the functionality of the access controller from the enterprise 105 to a cloud-based gateway that may be located, for example, in the mobile operator'"'"'s core network. Alternatively, the cloud-based gateway may be located elsewhere and operated by a third party (e.g., an entity other than the mobile operator or the enterprise).
If the components of the gateway 300 are run as a virtual application, then in some implementations the gateway 300 may employ a Network Function Virtualization (NFV) architecture. NFV refers to an architecture for telecommunication services as published by the European Telecommunications Standards Institute (ETSI) in a series of documents available from the ETSI website (See Network Functions Virtualization (NFV); Infrastructure Overview, ETSI GS NFV-INF 001 V1.1.1 (2015-01), http://www.etsi.org/deliver/etsi_gs/NFV-INF/001.sub.--099/001/01.01.01.su-b.--60/gs_NFV-INF001v010101p.pdf). NFV uses a generic hardware platform and software adapted for the generic hardware platform. Thus, NFV creates a network that can be more flexible and dynamic than a legacy communication network. In NFV-based networks, a Virtual Network Function (VNF) decouples the software implementation of the network function from the infrastructure resources it runs on by virtualization. A network service is based on one or more VNFs and/or Physical Network Functions (PNFs), their interconnections, and chaining definitions. The VNFs can be executed on a wide variety of generic hardware processing platforms (e.g., x86 based hardware). Therefore, VNFs may be installed, removed, and moved between hardware facilities much more easily, less costly and thus, more frequently.
Referring again to
Thus, each instance of the SN 310 acts as a serving controller to one or more RN clusters and each SN 310 acts as a control point for all radio nodes in the radio node cluster. As the number of RN clusters increase, new instances of the SN 310 can be created to meet the requirements. While in principle there is no limit on the number of SN instances that are allowed, in practice it will depend on constraints such as CPU, memory, networking interfaces and so on. Each SN is responsible for 3G and LTE Radio Resource Management (RRM) of all the RN clusters to which it is connected and admission control of RRC Connections. In addition, the SN is responsible for coordinating RF parameters using Localized SON (e.g., d-SON) and for coordinating the mobility of RNs within or between clusters. Since the architecture of each SN supports centralized layer L3 (RRC/RRM) processing, it is able to provide a wide variety of features. For instance, each SN can provide centralized admission control that enables the SN to re-direct low priority users to other cells. In addition, each SN can provide fast handovers since they are completely hidden from the EPC. The SNs can also perform LTE RRC Reestablishment procedures across cells and RANs and, furthermore, they can support soft handovers in UMTS. The SNs can also optimize LTE call setup times by combining and/or piggybacking multiple control plane messages between a radio node and a SN, which is required in high latency backhaul networks.
As previously mentioned, the SNs 310 may communicate with one another over conventional protocols using, for example, X2/Iur connections. Communication between the SNs 310 and the cluster manager/OAM 320 may also employ conventional protocols such as SNMP/TR-069. Likewise, the SNs 310 and the CN aggregator/mobility anchor 330 may employ conventional protocols such as Iuh (for UMTS) and 51 (for LTE over SCTP/IP). Of course, alternative protocols may be employed instead, including both standard and proprietary protocols.
Protocol layers that may be employed in the control plane between the mobility anchor and the RNs and between the mobility anchor and the SGW in the core network may include a Transport Internet Protocol (IP) layer, a user datagram protocol (UDP) and a GPRS Tunneling Protocol-User plane (GTP-U) for creating IP-based tunnels. It should be noted that the X1, X1″ and X1-u interfaces shown in
In some embodiments each of the SNs may perform logical open systems interconnection (OSI) layer L3 processing. In some cases the SNs may also perform at least a portion of logical OSI layer L2 processing such as Packet Data Control Protocol (PDCP) processing, for example.
The cluster manager and operations/administration module (OAM) 320 shown in
In one implementation, the self-discovery/radio node join procedure may proceed as follows. A radio node is pre-provisioned with the fully-qualified domain name (FQDN) of the gateway 300. When an RN boots up, it performs a Domain Name System (DNS) resolution process to obtain the IP address of the gateway 300. The RN then sends a Join Request message to the gateway 300 requesting a software image download from the cluster manager/OAM module 320. The cluster manager/OAM module 320 authenticates the RN and sends a Join Accept message upon successful authentication. The Join Accept message contains the SN information that is going to serve this RN such as an identifier and IP address of the SN to which it is to connect and any necessary software needed to establish that connection. The cluster manager/OAM module 320 selects the SN instance that is to serve this particular RN based on a variety of factors (“signatures”) that may include, without limitation, the geographic location of the RN (e.g., GPS coordinates, physical address, RF topology, IP address), the results of the topology discovery process performed by the A-SON module 340, and load balancing considerations based on the current load of the SNs.
The cluster manager/OAM module 320 can initiate the launch of a new SN instance when needed. For instance, in the event of an unrecoverable failure at a SN, the cluster manager/OAM module 320 can redirect a cluster to a different SN instance or launch a new SN instance. Based on the current load, the cluster manager/OAM module 320 can offload some of the SNs and change the cluster configuration. The cluster manager/OAM module 320 can also support additional features such as location locking. For example, an RN may be factory-provisioned so that it is only operable at a fixed location.
The core network (CN) aggregator and mobility anchor module 330 shown in
The mobility anchor in the CN aggregator and mobility anchor module 330 hides from the core network all mobility events between the RN clusters and mobility events between SNs. All data plane traffic for LTE and UMTS terminate at the mobility anchor. The mobility anchor also provides soft handover functionality between RN clusters and manages PSC/PCI hand-in disambiguation across RN clusters when UEs move from the macro network to the small cell network and need to be assigned to an RN cluster. The mobility anchor can also provide GTP anchoring between the RNs and the EPC.
As noted above, the individual SNs each include Self-Organizing Network (SON) functionality, which facilitates automation of self-configuration, self-management, self-optimization and self-healing of the individual RN clusters. SON is an automation technology designed to make the planning, configuration, management, optimization and healing of mobile radio access networks simpler and faster. SON functionality and behavior has been defined and specified in generally accepted mobile industry recommendations produced by organizations such as 3GPP (3rd Generation Partnership Project) and the NGMN (Next Generation Mobile Networks). SON features are available for both LTE and UMTS. Typically, each SN 310 operates in a distributed SON (d-SON) architecture mode. Thus, the SN 310 configures and optimizes the cluster with which it is associated. When a new RN is added, it discovers the SN. From that point on, the SN takes responsibility for providing the RN with its software image and radio configuration. If an RN inside the cluster drops off the network, the SN servicing it adjusts the configuration of neighboring RNs to fill the coverage hole.
The A-SON module 340 shown in
The A-SON module 340 can perform a variety of tasks. For instance, it can allocate physical cell identifiers (PCI) and primary scrambling codes (PSC) and their reuse across RN clusters associated with different SNs. The A-SON module 340 can also dynamically allocate transmit power assignments of radio nodes, perform closed loop monitoring of inter-SN mobility KPIs, dynamically update the neighbor topology and the neighbor tables maintained by the SNs and detect RF coverage overlaps and holes between cells. Mobility Robustness Optimization (MRO) and Mobility Load Balancing (MLB) may also be performed by the A-SON module 340.
The individual d-SON elements in the RN clusters cooperate with the A-SON module 340 to perform a number of tasks, including coordinating the SON configurations as received from A-SON module 340, providing periodic measurements and KPIs to the A-SON module, and dynamic fractional frequency reuse (FFR) assignments within the SNs, which may be based, for example, on the number of cell edge users and cell center users in the RNs served by the respective SNs at any given time. The d-SON elements also perform over the air frequency and phase synchronization of the RNs with other RNs and macro cells, when possible.
As further shown in
In some implementations the gateway 300 may operate as a multimode gateway supporting two or more bands. For example, one band may operate in accordance with LTE standards and the other may operate in accordance with UMTS standards. Accordingly, the gateway 300 can support clusters in which independent LTE and UMTS small cells are co-located, each being served by a dual or multi-mode RN.
A multimode gateway may be employed in a variety of different circumstances. For instance, a network operator may deploy the system and reserve one of the bands for themselves and lease the other band to another network operator. Alternatively, a third party may own and deploy the multimode network. In either case, each network operator generally desires to use their own core network. In such a case the CN aggregator may have multiple S1 connections to the different core networks of the operators. Additionally, each dual (or multi) mode RN may have two (or multi) dedicated proprietary X1 connections to the SNs, each representing a different operator. From the operators'"'"' perspective, there appears to be an SN and a set of RNs dedicated to each operator, although the different SNs may reside on a common hardware platform. To provide this capability the SNs are provided with functionality that allows each operator to configure their cells independently of the other.
In some cases the multimode gateway can facilitate cooperation among the different network operators. The different operators would be aware of the shared resources (e.g., RNs and all or various subcomponents of a SN) and would allow information to be shared between them in order to allow joint optimization of the coverage and capacity for UEs supported by the different operators.
With continuing reference to
Based on the measurement report, the SN calculates to perform a handover from the source RN to the target RN. In this example both the source and target RNs are associated with the same SN instance. In response, at 2, the SN uses the UE context information to set up a radio link between the SN and target RN using the X1 interface by sending a radio link configuration request. At 3, the target RN responds with a radio link configuration response. In this way the target RN is prepared by the SN for the handover of the UE. After the target RN has been prepared, the SN sends a flow setup request at 4 to the mobility anchor. In this way the SN interacts with the mobility anchor to establish a new GTP tunnel between the target RN and mobility anchor. The mobility anchor responds with a flow setup response at 5.
At this point all GTP information has been exchanged that is needed to set up a tunnel between the mobility anchor and the target RN, but no traffic is being communicated on that tunnel yet. That is, as indicated by arrows 420, 425 and 430, all user traffic is still going through the source RN. Next, as indicated by arrow 435, GTP traffic also starts flowing from the mobility anchor to the target RN as well as source RN. Subsequently, the mobility anchor stops sending GTP traffic to the source RN. Thus, all downlink data destined for the UE now comes from the SGW to the mobility anchor, and then to the target RN, which at this point is simply buffering the traffic. All uplink traffic, however, is still going through the source RN, to the mobility anchor and then to the SGW.
Next, at 6 the SN sends a RRC connect reconfiguration request to the UE instructing it to switch to the target RN. At 7-9, a conventional exchange of messages occurs between the UE and the target RN to synchronize the UE and the target RN. For instance, the UE undergoes at 8 a Random Access Channel (RACH) procedure over a logical RACH channel in order to attach to the target RN. Likewise, at 9 the target RN responds with the UL allocation and timing advance information.
At this point the UE is now synchronized with the target RN and at 10 the UE sends a RRC connection reconfiguration complete message to the SN. From a layer 3 signaling point of view, the handover is now complete. Finally, at 11 the SN uses the X1 interface to send a radio link delete request to the source RN and at 12 the source RN acknowledges by sending the SN a radio link delete response. The target RN now sends the buffered user traffic to UE over the DTCH, as indicated by arrow 440. Accordingly, uplink and downlink traffic can now be communicated between the UE and target RN using DTCH and between the target RN and mobility anchor using GTP (arrow 445), as well as between the mobility anchor and the SGW using GTP (arrow 450).
As the message flow chart in
The primary difference between the messages that are exchanged in the inter-SN handover of
In the following only those messages that are different from those shown in
As shown in
Several aspects of telecommunication systems will now be presented with reference to gateway described in the foregoing detailed description and illustrated in the accompanying drawing by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. By way of example, an element, or any portion of an element, or any combination of elements may be implemented with a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a non-transitory computer-readable media. Non-transitory computer-readable media may include, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., compact disk (CD), digital versatile disk (DVD)), a smart card, a flash memory device (e.g., card, stick, key drive), random access memory (RAM), read only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable media for storing software. The non-transitory computer-readable media may be resident in the processing system, external to the processing system, or distributed across multiple entities including the processing system. Non-transitory computer-readable media may be embodied in a computer-program product. By way of example, a computer-program product may include one or more computer-readable media in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.