Patent Publication Number: US-2020305077-A1

Title: Virtual cells for radio access network (ran) sharing

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation of U.S. patent application Ser. No. 16/150,461, filed Oct. 3, 2018, which application is a continuation of U.S. patent application Ser. No. 15/162,218, filed May 23, 2016, which prior application claims priority to, and thus the benefit of an earlier filing date from, U.S. Provisional Patent Application No. 62/165,549 (filed May 22, 2015), the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     Cellular telephony continues to evolve at a rapid pace. Cellular telephone networks currently exist in a variety of forms and operate using a variety of modulations, signaling techniques, and protocols, such as those found in 3G and LTE networks (3rd Generation of mobile telecommunications technology and Long Term Evolution, respectively). As consumers require more capacity, the networks usually evolve. For example, some carriers, or Mobile Network Operators (MNOs), employ the faster LTE because, as demand for data and voice increased, the MNOs needed faster networks. 
     And, the very different ways in which the networks operate further complicate network changes. For example, 3G networks would handle wireless communications through a base station by connecting the communications to a Public Switching Telephone Network (PSTN) through a Mobile Telephone Switching Office (MTSO) of the MNO. In LTE, however, wireless communications through base stations are typically handled through packet switching networks so a connection to the PSTN is not necessary in many cases. In either case, each network of a MNO includes some sort of Mobile Central Office that is operable to handle the communications between wireless devices (also known as user equipment) and base stations. 
     Still, even with these faster networks, the demand for more data appears to outpace MNO capabilities. And, the demand can change from day to day or even hour to hour. For example, when a location experiences a rapid increase in population, such as what occurs during sporting events, the MNOs capacity can be overwhelmed. And, when an MNO&#39;s capacity is overwhelmed, communications between user equipment and base stations get dropped. 
     Shared base station deployments exist but they are typically isolated and relatively small. And, several challenges have prevented their adoption due to needed size to accommodate many users. For example, neighbor cell provisioning across networks with large quantities of cells is difficult. And, the integration of network to network interfaces between small cells and larger “macro” network cells is even more difficult. Moreover, when user equipment (UEs) traverses from cell to cell, the constant change in signaling significantly taxes and drains the batteries of the UEs. That is, a larger macro cell saves UE battery life because it provides more coverage control of its base stations such that the UE does not need to constantly register with as many base stations. 
     SUMMARY 
     Systems and methods herein provide for the aggregation of a plurality of wireless base stations for access by a Mobile Central Office (MCO) of an MNO communicating with user equipment (UEs, such as wireless devices) through a network. In one embodiment, a communication system includes a first plurality of wireless base stations, each being operable to communicate with UEs. For example, each wireless base station is generally operable to handle a session (i.e., a voice call, a data connection, etc.) from a UE and to handoff the session to another of the wireless base stations when the wireless device moves into a range of the other wireless base station. The system also includes a base station aggregator operable to aggregate the wireless base stations into a virtual base station, and to interface with the MCO. The base station aggregator may be further operable to process a request from the MCO for access to communications provided by the virtual base station, to grant the request, to intermediate on behalf of the MCO, and to exchange communications between the MCO and a UE subscribing to the MCO and operating within the virtual base station. 
     The various embodiments disclosed herein may be implemented in a variety of ways as a matter of design choice. For example, some embodiments herein are implemented in hardware whereas other embodiments may include processes that are operable to implement and/or operate the hardware. Other exemplary embodiments, including software and firmware, are described below. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Some embodiments of the present invention are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings. 
         FIGS. 1A and 1B  are block diagrams of an exemplary wireless communication system. 
         FIG. 2  is a flowchart illustrating an exemplary process operable with the wireless communication system of  FIG. 1 . 
         FIG. 3  is a block diagram of an exemplary base station aggregator. 
         FIG. 4  is an exemplary messaging diagram of the base station aggregator. 
         FIG. 5  is a block diagram of an exemplary computing system in which a computer readable medium provides instructions for performing methods herein. 
     
    
    
     DETAILED DESCRIPTION OF THE FIGURES 
     The figures and the following description illustrate specific exemplary embodiments of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within the scope of the invention. Furthermore, any examples described herein are intended to aid in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the invention is not limited to the specific embodiments or examples described below. 
       FIGS. 1A and 1B  are block diagrams of an exemplary wireless communication system. The wireless communication system includes a base station aggregator  101  and a plurality of wireless base stations  106 - 101 . The base station aggregator  101  is operable to interface with an MCO  102  to aggregate the base stations  106 - 101  into a virtual base station  103  that provides additional capacity to the MCO  102 . 
     To illustrate, in  FIG. 1A , the MCO  102  is communicatively coupled to a plurality of wireless base stations  106 - 102  to provide communications to UEs operating within cell coverages  110 - 102  of the wireless base stations  106 - 102 . The MCO  102  operates and manages each of the base stations  106 - 102  so as to provide a network coverage area  104  for each of its subscribing UEs. Occasionally, however, the MCO  102  needs additional capacity for its subscribing UEs. This may be due to UEs moving out of the network coverage area  104  of the MCO  102 , increased capacity requirement due to UEs overloading a particular base station  106 - 102 , or the like. The MCO  102 , in this regard, communicates with the base station aggregator  101  to acquire additional capacity from the virtual base station  103 . 
     The base station aggregator  101  can provide the additional capacity of the virtual base station to the MCO  102  for its subscribing UEs, as well as any other UEs “roaming” into the network coverage area  104 . Generally, though, the base stations  106 - 101  are comprised of a plurality of independent operators and/or quickly deployable “hotspots” with each covering a limited coverage area  110 - 101  (e.g., a cell). For example, indoor conventions hosting a relatively large number of people may need wireless telephony for those people. Oftentimes, the buildings of these indoor conventions shield communications of the larger MCO network. Accordingly, one or more hotspot base stations  106 - 101  may be deployed within the building so that the people attending the convention can receive wireless telephony services. And, while the base station aggregator  101  operates and maintains the hotspot base station(s)  106 - 101  as a virtual base station  103 , the MCO  102  may control the virtual base station  103  and the UEs in a manner that is transparent to the UEs. 
     Each of these base stations  106 - 101  may employ communication protocols (e.g., Edge network, 2G, 3G, etc.) that differ from that of the MCO  102  (e.g., LTE) and its base stations  106 - 102 . The base station aggregator  101  is operable to independently communicate with each of the base stations  106 - 101  and provide a translation which allows the base station aggregator  101  to aggregate the base stations  106 - 101  into a virtual base station  103 , as illustrated in  FIG. 1B . 
     Thus, as illustrated in  FIG. 1B , when the base station aggregator  101  grants access to the virtual base station  103 , the virtual base station  103  and its associated base stations  106 - 101 , come under control of the MCO  102  and are considered part of the network coverage area  104  of the MCO  102 . The base station aggregator  101  then translates communications between the MCO  102  and the base stations  106 - 101  until the additional capacity is no longer required by the MCO  102 . 
     Based on the forgoing, an MCO is any system, apparatus, software, or combination thereof operable to maintain or otherwise support wireless communications, including data and voice, with subscribers via UEs (e.g., mobile handsets and other wireless devices). Accordingly, the MCO may be a wireless communications carrier or network (e.g., carbon MNO) employing, for example, 2G, 3G, LTE, WiFi, or any combination thereof. And, a base station  106  is any device or system operable to communicate with UEs via Radio Frequency (RF). 
     Generally, when MCOs are owned, managed, or otherwise controlled by separate entities, the competitive nature of the environment prevents cooperation among of MCOs, such as MCO  101 . However, the ability to share capacity with MCOs can be quite beneficial. For example, in emergency situations where the MCO happens to be over capacity with its subscribers and a base station  106 - 101  operating in the same area is not, moving capacity from the base station aggregator  101  would advantageously allow the over capacity MCO to establish communications for more of its subscribers and ensure that calls go through. 
     As used herein, capacity may include Radio Frequency (RF) spectrum, data throughput, backhaul capacity, network processing (e.g., virtualized RANs), channels in a Time Division Multiple Access (TDMA) signal, Code Division Multiple Access (CDMA) channels, channels in a Frequency Division Multiple Access (FDMA) signal, channels in the Orthogonal Frequency Division Multiplexing (OFMD), Carrier Sense Multiple Access (CSMA), and the like. Backhaul capacity may include, among other things, a backhaul portion of a network including intermediate links between a core network (or a backbone network) and smaller subnetworks at an edge of a hierarchical network. Backhaul capacity can also include an obligation to carry data packets to and from a global network, and the like. 
     In some embodiments, the base station aggregator  101  is operable to do much of the processing of the UE communications as a Virtualized Radio Access Network (VRAN, a.k.a. a “cloud RAN”) with each base station  106 - 101  providing a digitized sample of the entire RF spectrum of interest that may be transmitted from the base station interface. In such an embodiment, the wireless base stations  106 - 101  may be configured with antennas, transceivers, and digitizers that digitize the radio communications of the RF spectrum in which the UEs operate. A digitized representation of the RF spectrum may thus be transmitted to a remote “cloud” of base station processing. For example, the base station aggregator  101  may allocate a particular frequency band of the radio frequency (RF) spectrum in which its subscriber UEs can operate. And, each base station  106 - 101  of the base station aggregator  101  may be configured to digitize that portion of the radio frequency (RF) spectrum. Then, each base station conveys the digitized spectrum to the base station aggregator  101  such that the communications of the UEs can be extracted and processed. 
     In some instances, the base station aggregator  101  is operable to receive digitized spectrums from the base stations  106 - 101  to constructively re-create the RF communications of a single UE. For example, a UE&#39;s signal may be detected/received by multiple base stations  106 - 101  of the virtual base station  103 . Some base stations  106 - 101  may have stronger detections of the UE whereas other base stations  106 - 101  may receive “multipath” aspects of the UE&#39;s signal. The virtual RAN processes the digitized spectrums of each of the base stations  106 - 101  and reconstructs the UE&#39;s signal from the “constructive interference” of the multipath and receptions by the base stations  106 - 101 . And, the baseband and MAC layers are calculated in the cloud, not at the antenna as in conventional cell networks. Thus, the base station greater  101  is operable to handle the call through the digitized or virtual RAN. 
     Although shown or described with respect to the base station aggregator  101  providing communication access to all of the base stations  106 - 101  of the virtual base station  103 , the invention is not intended to be limited as such. The base station aggregator  101  may be operable to form multiple virtual base stations  103  from the base stations  106 - 101  and provide the additional capacity to the MCO  102 , depending on the needs of the MCO  102 . For example, the MCO  102  may only require capacity from one base station  106 - 101 . Accordingly, the base station aggregator  101  may virtualize that single base station  106 - 101  into its own virtual base station  103  and provide that capacity to the MCO  102 . 
       FIG. 2  is a flowchart illustrating an exemplary process  200  operable with the wireless communication system of  FIG. 1 . In this embodiment, the base station aggregator  101  operates the plurality of wireless base stations  106 - 101 , with each base station  106 - 101  being operable to communicate with a plurality of UEs, in the process element  201 . As mentioned, the base station aggregator  101  is operable to aggregate the base stations  106 - 101  into a virtual base station  103 , in the process element  202 . The base station aggregator  101  then processes a request from the MCO  102  for access to at least a portion of the communications provided by the virtual base station  103 , in the process element  203 . 
     The base station aggregator  101  then determines whether the virtual base station  103  can sustain the communications for the MCO  102 , in the process element  204 . For example, the base station aggregator  101  may determine whether it has any capacity to share from the virtual base station  103 . If the virtual base station  103  can sustain the communications for the MCO  102  (i.e., capacity does exist), then the base station in aggregator  101  grants request and intermediates on behalf of the MCO  102 , in the process element  206 . From there, the base station aggregator  101  exchanges communications between the MCO  102  and a subscribing (or roaming) UE of the MCO  102  through the base stations  106 - 101  of the virtual base station  103 , in the process element  207 . If the base station aggregator  101  has no available capacity, then the base station aggregator  101  may deny the access to the virtual base station  103 , in the process element  205 . 
     Although shown and described with respect to the base station aggregator  101  being operable to provide capacity to a single MCO (e.g., the MCO  102 ), the invention is not intended be limited as such. For example, the base station aggregator  101  may be operable to interface with any number of MCOs to provide additional capacity based on the capacity of the base stations  106 - 101  of the virtual base station  103 . It should also be noted that access to the additional capacity of the virtual base station  103  can change based on the requirements of the MCO  102 . For example, when the MCO  102  no longer requires the additional capacity of the virtual base station  103 , then the base station aggregator  101  may close access to the additional capacity of the virtual base station  103  at the direction of the MCO  102 . 
     Moreover, the base station aggregator  101  may be operable to create the virtual base station  103  from the base stations  106 - 102  as well as the base stations  106 - 101 . For example, assume that the MCO  102  has excess capacity that can be used by another MCO. The station aggregator  101  may acquire those base stations  106 - 102  and create a virtual base station  103  from those base stations. Additionally, the virtual base station  103  created from the base stations  106 - 101  and/or the base stations  106 - 102  of the MCO  102  may include an MCO determined coverage area, MCO determined cell identifier assignments, and native network MCO addressing. Accordingly, the base station aggregator  103  is any device, system, software, or combination thereof operable to virtualize any combination of base stations  106 - 101  and  106 - 2  into a virtual base station  103  for use by the MCO  102  or any other MCO requesting additional capacity. 
       FIG. 3  is a block diagram of an exemplary base station aggregator  101 . In this embodiment, the base station aggregator  101  comprises a virtual RAN processor  251  that is operable to interface with a plurality of wireless base stations  106 - 101 . As each of these base stations  106 - 101  may employ different communication protocols (e.g., 2G, 3G, LTE, etc.), the virtual RAN processor  251  is operable to independently communicate with each of these base stations  106 - 101  according to their various protocols. The virtual RAN processor  251  establishes a communication interface that aggregates the base stations  106 - 102  into virtual base station  103  such that the MCO  102  can acquire the additional capacity from those base stations  106 - 102  through the interface. 
     As mentioned, the base station aggregator  101  is operable to interface with a plurality of MCOs. However, MCOs may also vary in terms of their communication protocols for various reasons. For example, many MCOs now employ the more modern LTE communication protocols to operate their communication networks (e.g., base stations  106 - 102  of the network coverage area  104 ). However, some MCOs have not upgraded to this communication protocol due to various reasons such as finances, catering to lower tier subscribers, etc. Accordingly, these MCOs employ older communication protocols, such as 2G and 3G. In whatever the case, the base station aggregator  101  comprises a protocol translator  252  that is operable to process requests for capacity based on the MCO&#39;s communication protocol and then translate communications from the MCO to the communication protocol of the virtual base station  103 . 
     To illustrate, assume that a first MCO employs the LTE communication protocol for its communication network to control its base stations and to communicate with UEs based on that protocol. Now assume that the virtual base station  103  comprises a mix of 2G and 3G base stations  106 - 101 . The virtual RAN processor  251  may implement the virtual base station  103  according to the lower tier service provided by the 2G communication protocol. The protocol translator  252  is operable to translate the LTE communications from the MCO to the lower tier 2G communication protocol to communicate with the virtual base station  103 . 
     When the protocol translator  202  receives a request for additional capacity from the LTE MCO, the virtual RAN processor  251  determines whether there is any available capacity in the virtual base station  103 . If so, the virtual RAN processor  251  indicates such to the protocol translator  252  to establish communications between the LTE MCO and the UEs operating within the virtual base station  103 . From there, the protocol translator  202  translates the LTE communication protocol to the lower tier 2G communication protocol, and vice versa, such that communications with the UEs operating within the coverage of the virtual base station  103  can be controlled by the LTE MCO. This, of course, may result in fewer services as the LTE communications offer a wider variety of, and typically faster, services. 
     Now consider an alternative scenario in which the MCO requesting additional capacity from the base station aggregator  101  operates with a 2G communication protocol and that the virtual base station  103  is comprised of a plurality of 3G base stations  106 - 101 . In this example, the virtual RAN processor  251  may present the virtual base station  103  as a 3G base station with more capabilities than the requesting MCO. The protocol translator  252  in this instance would translate communications from the 2G MCO to the 3G virtual base station  103 . Accordingly, when the 2G MCO acquires capacity from the base station aggregator  101  and essentially controls the base stations  106 - 101  of the virtual base station  103 , the protocol translator  252  translates the lower tier 2G communication protocol to the higher tier 3G communication protocol of the virtual base station  103 . This, of course, may result in the 2G MCO providing lower tier services to its UEs operating within the coverage of the virtual base station  100 . 
     The above two examples merely illustrate how the virtual RAN processor  251  can aggregate into a single communication protocol operable with the virtual base station  103  and how the protocol translator  252  can translate the communications from a requesting MCO to the virtual base station  103 , and vice versa. However, the invention is not intended be limited to these two examples as any combination of virtual base station aggregation and protocol translation can be implemented. For example, the virtual RAN processor  251  can aggregate the base stations  106 - 101  in any combination of communication protocols. In some instances, the virtual base station  103  may be an aggregation of multiple communication protocols or a single communication protocol. And, as mentioned, base station aggregator  101  can aggregate the base stations  106 - 101  in any number of virtual base stations  103  to provide capacity to a requesting MCO. The combination of the virtual RAN processor  251  and the protocol translator  252  also provides negotiation of service provided by the protocols. For example, the virtual RAN processor  251  and the protocol translator  252  implement a lower tier protocol may be used when either the MCO  102  or the virtual base station  103  employs such. However, same protocols can be implemented when the virtual base station  103  and the MCO  102  are the same type. 
     The base station aggregator  101  may also include an account manager  253  that is operable to maintain accounts from requesting MCOs. For example, a requesting LTE MCO may have a different fee structure than a requesting 2G MCO. Accordingly, the account manager  253  charges the requesting MCO for additional capacity provided by the base station aggregator  101  based on the structure. The account manager  253  may also track minutes of service consumed by subscribing or roaming UEs and relay that information to the requesting MCO such that it can charge the UEs accordingly. 
       FIG. 4  is an exemplary messaging diagram of the base station aggregator  101 . In this embodiment, an MNO/MCO  102  operates its base stations  106 - 101 - 1 - 106 - 102 -N in the network coverage area  104  (wherein the reference number “N” represents an integer greater than “1” and not necessarily to any other “N” reference designated herein). The base station aggregator  101  operates its base stations  106 - 101 - 1 - 106 - 101 -N and aggregates them into the virtual base station  103 . When the MNO/MCO  102  determines that it needs additional capacity, and transmits a capacity request to the base station aggregator  101 . The base station aggregator  101 , in turn, detects its available capacity within the virtual base station  103 . If capacity is available, then the base station aggregator  101  conveys to the MNO/MCO  102  that capacity is available and that the access to the virtual base station  103  is granted. 
     After accesses been granted by the base station aggregator  101 , the MSO/MCO  102  conveys control messaging such as transmit power control, billing information, and the like, to the base station aggregator  101 . The base station aggregator  101  translates the messaging such that communications between the MNO/MCO  102  and the virtual base station  103  can be established and thus communications between the UEs operating in the virtual base station  103  and the MNO/MCO  102  can be established. When the capacity is no longer required by the MNO/MCO  102 , the base station aggregator  101  reacquires the virtual base station  103  and directs the MNO/MCO  102  to relinquish its control over the virtual base station  103 . 
     Advantages of the above embodiments provide a rapid integration of network to network interfaces between smaller independent cells and a macro network with little to no disruption of the service to the UEs. For example, the aggregation of smaller independent cells (e.g., the base stations  106 - 101 ) into the virtual base station  103  provides a simpler provisioning of mobility procedures for larger MNOs/MCOs. The self-organizing network (SON) process of the base station aggregator  101  also provides auto provisioning of the base stations  106 - 102  based on the MNOs/MCOs needs. That is, the base station aggregator  101  is able to create virtual base stations  103  based on the capacity needs of the MNOs/MCOs. 
     And, when a virtual base station  103  is provided to a requesting MCO, the requesting MCO acquires control of the virtual base station  103  and its existing base stations  106 - 101  such that the requesting MCO can process the communications to reduce interference and/or reduce “ping-ponging”. For example, the requesting MCO can control the transmit power of the virtual base station  103  and its existing base stations  106 - 101  (i.e., through the translation provided by the base station aggregator  101 ). The SON properties of the base station aggregator  101  allows the MNO/MCO  102  to direct the virtual base station  103  to adjust transmit power of its existing base stations  106 - 101  such that UEs only operate with a higher power base station  106 - 101  of the virtual base station  103  as opposed to ping-ponging between proximate base stations  106 - 101  of the virtual base station  103 . This assists in reducing power consumption by the UEs operating within the virtual base station  103 . 
     Other advantages of the base station aggregator  101  the ability to assign cell identifier plans to each virtual base station  103  according to MNO numbering plans and needs and to provide mobility procedures (e.g., handoffs) between the virtual base station  103  and the base stations  106 - 102  of the MCO  102 . Additionally, the base station aggregator  101  can aggregate base stations  106 - 101  across any geographical area. For example, the base station aggregator  101  may be communicatively coupled to the base stations  106 - 101  and managed in the cloud such that the base stations  106 - 101  may be operated globally, thereby allowing the MCO  102  global access to the virtual base station  103  for its subscribing and roaming UEs. 
     The invention can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements. In one embodiment, the invention is implemented in software, which includes but is not limited to firmware, resident software, microcode, etc.  FIG. 5  illustrates a computing system  300  in which a computer readable medium  306  may provide instructions for performing any of the methods disclosed herein. 
     Furthermore, the invention can take the form of a computer program product accessible from the computer readable medium  306  providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, the computer readable medium  306  can be any apparatus that can tangibly store the program for use by or in connection with the instruction execution system, apparatus, or device, including the computer system  300 . 
     The medium  306  can be any tangible electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device). Examples of a computer readable medium  306  include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Some examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD. 
     The computing system  300 , suitable for storing and/or executing program code, can include one or more processors  302  coupled directly or indirectly to memory  308  through a system bus  310 . The memory  308  can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code is retrieved from bulk storage during execution. Input/output or I/O devices  304  (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers. Network adapters may also be coupled to the system to enable the computing system  300  to become coupled to other data processing systems, such as through host systems interfaces  312 , or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters.