Patent Publication Number: US-2012044876-A1

Title: Method and apparatus for virtualization of wireless network

Description:
BACKGROUND OF THE INVENTION 
     Mobile Cellular Operators have traditionally acquired expensive spectrum licenses and have deployed their own Radio Access Network (RAN) and Core Networks (CN). New network deployments take a long time and require large capital expenditures. 
     In some countries the coverage offered by different operators are fairly similar as far as the users are concerned. RAN basically allocates a predetermined spectrum bandwidth for data and the operator&#39;s differentiations may be on the services offered on top of these allocated spectrum bandwidth to the end user. 
     The demand for wireless broadband and mobile Internet will further fuel deployment of the next generation RANs, 4 th  Generation (4G). Emerging 4G broadband technologies, such as, for example WiMAX and/or long term evolution (LTE) radio systems, may require large chunks of frequencies spectrum. The useful and globally available frequency spectrums for 4G are limited and scarce in most countries. Furthermore, auctions for these spectrums may result in even smaller frequency spectrum pieces for each operator. Thus, a more efficient use of the frequency system is needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanied drawings in which: 
         FIG. 1  is an illustration of a wireless communication system according to some exemplary embodiments of the present invention; 
         FIG. 2  is an illustration of a protocol flow between components of a wireless communication system according to some exemplary embodiments of the present invention; 
         FIG. 3  is a flowchart depicting a method of sharing a wireless spectrum by a plurality of mobile devices of different operators according to exemplary embodiment of the invention; and 
         FIG. 4  is an illustration of a block diagram of a base station according to exemplary embodiments of the invention. 
     
    
    
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However it will be understood by those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention. 
     Some portions of the detailed description, which follow, are presented in terms of algorithms and symbolic representations of operations on data bits or binary digital signals. These algorithmic descriptions and representations may be the techniques used by those skilled in the signal processing arts or/and in wireless communication arts to convey the substance of their work to others skilled in the art. 
     Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer and/or computing system and/or medium access controller (MAC) and/or communication processor, or similar electronic computing device, that manipulates and/or transforms data represented as physical, such as electronic, quantities within the computing system&#39;s registers and/or memories into other data similarly represented as physical quantities within the computing system&#39;s memories, registers or other such information storage, transmission or the like. In addition, the term “plurality” may be used throughout the specification to describe two or more components, devices, elements, parameters and the like. For example, “plurality of mobile stations” describes two or more mobile stations. 
     It should be understood that embodiments of the present invention may be used in a variety of applications. Although the present invention is not limited in this respect, the circuits and techniques disclosed herein may be used in many apparatuses such as communication devices of a radio system. The communication devices intended to be included within the scope of the present invention include, by way of example only, mobile stations, base stations and access points of radio systems such as, for example wireless local area network (WLAN) which also may be referred as WiFi, wireless metropolitan area network (WMAN) which also may be referred as WiMAX, a wireless personal area network (WPAN) such as, for example using Bluetooth™ protocols, two-way radio transmitters, digital system transmitters, analog system transmitters, cellular radiotelephone transmitters, digital subscriber lines, LTE cellular systems and the like. 
     Some embodiments of the invention may be implemented, for example, using a machine-readable medium or article which may store an instruction or a set of instructions that, when executed by a processor or machine, cause the processor or machine to perform a method and/or operations in accordance with embodiments of the invention. Such a machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The machine-readable medium or article may include, for example, any suitable type of memory unit, memory device, memory article, memory medium, storage device, storage article, storage medium and/or storage unit or the like. The instructions may include any suitable type of code, for example, source code, compiled code, interpreted code, executable code, static code, dynamic code, or the like, and may be implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language, e.g., C, C++, Java, assembly language, machine code, or the like. 
     In accordance with embodiments of the invention, a channel may be a physical transfer medium. The physical transfer medium may be used to transfer signals such as, for example, informative data signals, training signals, pilot signals, sub-carriers signals, preamble signals and the like, that may be modulated by one or more modulation scheme. Furthermore, the channel may be a combination of the physical transfer medium, components of the transmitter and/or the receiver, for example path loss, noise, interference or the like. It should be understood to the skilled artisan that embodiments of the invention may operate with many types of signals, which partially mention above, and the invention is in no way limited to the above mentioned signals. 
     Turning first to  FIG. 1 , an illustration of a wireless communication system  100  according to some exemplary embodiments of the present invention is shown. Wireless communication system  100  may include, but not limited to, a first core network  110  operated by a first operator  110  or service provider, a second core network  120  operated by a second operator  120  or service provider, a Virtual Private Network (VPN) cloud  130 , a multi-Virtual Routing &amp; Forwarding (VRF) Customer Edge (CE)  140  and a base station  150 . With embodiments of the present invention, an operator may be, for example, an organization or company associated with or operating a network, including equipment. 
     According to one exemplary embodiment of the invention core network  110  may include, but is not limited to, a servicing gateway (S-GW)  111 , a Mobility Management Entity (MME)  112 , a Packet Gateway (P-GW)  113 , a Home Subscriber Server (HSS)  114 , Operations, Administration, Management (OAM)  115 , a Policy Charging Rules Function (PCRF)  116 , an operator core network cloud  117  and an Internet and/or other services  118 . Core network  120  may includes, but not limited to, an S-GW  121 , a MME  122 , a P-GW  123 , a HSS  124 , an OAM  125 , a PCRF  126  and an Internet and/or other services  128 . 
     According to this example, core network  110  may be operably coupled to VPN cloud  130  via a Client Edge (CE)  138  and a Provider Edge (PE)  134 . Core network  120  may be operably coupled to VPN cloud  130  via a CE  138  and a PE  132 . 
     According to one example embodiment of the invention, wireless communication system  100  includes a Long Term Evolution (LTE) cellular system and Evolved Packet Core (EPC). According to this example, VPN cloud  130  may include a Multi-Protocol Label Switching (MPLS) core  135 . According to embodiments of the invention, MPLS  135  is a mechanism which may be used in 4G cellular communication systems such as, for example LTE and WiMAX in order to direct and carry data from one network node (e.g., CE  139  and PE  134 , CE  138  and PE  132 ) to the next network node for example PE  136 . MPLS  135  mechanism may be used to create virtual links between distant wireless communication system  100  nodes. For example, MPLS mechanism  135  of VPN cloud  130  may create virtual links between core networks  110  and  120  to base station  150  via multiple virtual routing and forwarding (VRF) CE  140 , although it should be understood that the scope of the present invention is not limited to this exemplary embodiment of the invention. 
     Base station  150  may include an eNB of LTE cellular system  153 . eNB may be defined as Evolved Node B. The eNB is a complex base station that handles radio communications with multiple devices in the cell and may carry out radio resource management and handover decisions. Base station  150  may include a virtual eNB  153  to be used with core network  110  and a virtual eNB  157  to be used with core network  120 , although the scope of the present invention is not limited in this respect. 
     Turning to  FIG. 2 , an illustration of a protocol flow between components of a wireless communication system according to an embodiment of the present invention is shown. In the embodiment shown, the protocol flow includes the flow of protocol commands for sharing Radio Access Network (RAN) generated by a base station (BS) virtualization for example eNB  220 . BS virtualization enables a BS (e.g. eNB  220 ) to operate two or more instantiation of BSs logically in a single physical BS (e.g., BS  150 ). Each virtualized instantiation may represent or be associated with an operator such that the subscribers of those operators may not see any difference between a virtualized BS and/or a non-virtualized BS. The flow of the protocol commands may be between a mobile station, for example User Equipment (UE)  210 , and a base station, for example eNB  220  that may include for example, BS  150 . According to one exemplary embodiment of the invention, an MME  230 , a HSS  240  and S-GW/P-GW  250  may be used for establishing the base station virtualization connections. 
     According to this exemplary embodiment, eNB  220  may broadcast system information by transmitting for example, a master information block (MIB) and plurality of system information blocks (SIBs) to UE  210 . In one example of an LTE system, the MIB may include information about a cell bandwidth, PHICH (Physical HARQ Indicator Channel) and the system frame number (SFN), number of transmit antennas and the like. The MIB may be scrambled with a cell-id, if desired. The SIBs may carry in the PDSCH, whose information is obtained from the PDCCH indicated by the control format indicator (CFI) field. 
     UE  210  may extract the MIB and the SIB (text block  215 ) and may send a radio resource control (RRC) connection request to the base station (e.g., eNB  220 ). For example, the RRC connection request may include a Non-Access Stratum (NAS) request. 
     According an embodiment of the invention NAS is a functional layer in the UMTS protocol stack between Core Network (CN) and the UE. The layer supports signaling and traffic between the CN of each operator to the UE of each operator, respectively. 
     Although the scope of the present invention is not limited to this exemplary embodiment, eNB  220  may extract from the NAS request a mobile country code (MCC) and an International Mobile Subscriber Identity (IMSI). eNB  220  may identify MPLS Virtual Routing &amp; Forwarding (VRF) for UE  210  (text block  224 ) and may identify a network manger address for example, an MME address (text block  226 ). In the next protocol step, eNB  220  may send NAS request to a network manager for example, MME  230 . MME  230  may control authentication and security on the data flow between UE  210  and HSS  240  may update a location of UE  210  at HSS  240 . Finally, eNB  220  may provide a data bearer procedure to UE  210  to provide service via S-GW and P-GW  250 , although the scope of the present invention is not limited in this respect. 
     Embodiments of the present invention may share RAN infrastructure by eNB virtualization, if desired. For example, the association between the Service Provider and Radio Access Network (RAN) operator may become virtual. The traffic and signaling routing may be achieved by various Virtual Private Network (VPN) technologies such as, for example MPLS, L2TP, IPSec, and the like. 
     Turning to  FIG. 3  a flow chart depicting a method of sharing a wireless spectrum by a plurality of mobile devices of different operators according to exemplary embodiment of the invention is shown. According to this embodiment, a home network base station (e.g. eNB  150 ) may receive from a mobile station (e.g., MS  119 ) of another operator (e.g., CN  110 ) a connection request to establish a connection with the home network base station (text block  300 ). For example, the message may be, or includes, an NAS request. The NAS request may include a mobile country code, a mobile network code and a mobile subscriber identification (ID) code, if desire. When used herein, “of” an operator or service provider may mean that equipment or service is associated with, controlled by or operated by an operator. E.g., a cellular service operator may provide service via base stations to mobile devices. 
     After, or in response to receiving the connection request, the home network base station may identify a home network of the requesting mobile station based on the mobile country code, the mobile network code and the mobile subscriber identification (ID) code and may generate a virtual base station (e.g. virtual eNB- 1   155  and virtual eNB- 2   157 ) of the other operator at the home network base station (text box  310 ). At this stage, a connection between the mobile station and the virtual base station may be established (text box  320 ). In some embodiments of the invention the connection may be established by identifying a network manager address (e.g., MME address) and sending the connection request to a network manager (e.g., MME  230 ), if desired. 
     Furthermore, station temporary and permanent identities such as, for example mobile country code, the mobile network code and the mobile subscriber identification (ID) code may be linked to a corresponding virtual base station context database, although the scope of the present invention is not limited in this respect. 
     Turning to  FIG. 4  an illustration of a block diagram of a base station  400  according to exemplary embodiments of the invention is shown. Base station  400  may include a virtual base station (BS) generator  410  which may generate a virtual BS  430  and a virtual BS  440 . Virtual BSs  430  and  440  may be connected to a transmitter (TX)  450  and a receiver (RX)  460  (shown with the dotted lines). It should be understood that TX  450  and RX  460  may be use both by the physical BS  400  and the virtual base stations  430  and  440 . 
     Furthermore, BS  400  may include a processor  420 , a memory  470 , a database  475  and antennas  480  and  490 . For example, processor  420  may control virtual BS generator  460  and to that end may use or execute a software application, instructions and data that may be stored in memory  470  and database  475 , although the scope of the present invention is not limited in this respect. 
     According to embodiment of the invention, antennas  480  and  490  may be any antenna that is used for wireless communication. For example, dipole antennas, antenna arrays and the like. Memory  470  and database  475  may be any storage medium used with base stations for example, hard disk, flash memories and the like. Processor  420  may be and/or includes, for example, a medium access controller (MAC), a physical layer (PHY) controller, a digital signal processor (DSP) and the like. 
     According to one exemplary embodiment of the invention, BS  400  may be a home network base station and may receive by antenna  490  and RX  460  a connection request from a mobile station of another operator and/or another network in order to establish a connection with BS  400 . The connection request may include a message that includes temporary and permanent identities of the mobile station such as, for example a mobile country code, a mobile network code and mobile subscriber identification (ID) code and other parameters, if desired. The temporary and permanent identities of the mobile station may be linked to corresponding virtual base station context database for example database  475  which may be use by each and both virtual base stations  430  and  44   o , if desired. 
     Processor  420  may identify a home network of said mobile station based on the mobile country code, the mobile network code and the mobile subscriber identification (ID) code. Processor  420  may identify a network manager address and may send a connection request to a network manager (e.g., MME  230 ). Processor  420  may command virtual BS generator  410  to generate at the home BS (e.g., BS  400 ) a virtual BS, for example virtual BS  440 , which may simulate a home BS of the mobile station home network, if desired. Virtual BS  440  may be operably connected to TX  450  and RX  460  in order to establish a connection between the mobile station and virtual BS  440 , although the scope of the present invention is not limited to this example. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.