Abstract:
Various communication devices may benefit from network sharing. For example, network sharing may be beneficial for long term evolution on unlicensed band (LTE-U) and/or licensed-assisted access (LAA) cells operating on an unlicensed spectrum according to the third generation partnership project. Further, LTE enhancements may be implemented for LAA to unlicensed spectrum, including LTE-U. A method may include preparing information related to a carrier and/or cell operating on a non-licensed spectrum. The method may also include providing, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum.

Description:
BACKGROUND 
     Field 
     Various communication devices may benefit from network sharing. For example, network sharing may be beneficial for long term evolution on unlicensed band (LTE-U) and/or licensed-assisted access (LAA) cells operating on an unlicensed spectrum according to the third generation partnership project (3GPP). Further, LTE enhancements may be implemented for LAA to unlicensed spectrum, including LTE-U. 
     Description of the Related Art 
     The fast update of LTE in different regions of the world shows both that demand for wireless broad data is increasing, and that LTE is an extremely successful platform to meet that demand. At the same time, unlicensed spectrum is being considered by more cellular operators as a complementary tool to augment their service offering. 
     Unlicensed spectrum may not be able to match the qualities of the licensed regime. However, those solutions that allow an efficient use of unlicensed spectrum as a complement to licensed deployments have the potential to bring great value to 3GPP operators, and ultimately, to the 3GPP industry as a whole. Given the widespread deployment and usage of other technologies in unlicensed spectrum for wireless communications in society, it is envisioned that LTE would have to coexist with existing and future uses of unlicensed spectrum. Existing and new spectrum licensed for exclusive use by international mobile telecommunications (IMT) technologies will remain fundamental for providing seamless coverage, achieving the highest spectral efficiency, and ensuring the highest reliability of cellular networks through careful planning and deployment of high-quality network equipment and devices. 
     LAA should not impact/interfere with other systems, such as, for example, Wi-Fi, more than an additional Wi-Fi network on the same carrier. According to regulatory requirements, only certain amount of data can be transmitted without a listen before talk (LBT) mechanism, which may not be feasible for cell discovery and cell specific broadcast signaling. This may cause a problem that broadcast signaling space in unlicensed spectrum is limited. Further, it is assumed, for example, that primary synchronization channel (PSS)/secondary synchronization channel (SSS)/common reference signal (CRS) and system information are transmitted without LBT. 
     LTE-U/LAA is assumed to support network/radio access network (RAN) sharing which may be problematic because a public land mobile network (PLMN) identification (ID) may be quite long in size and all the necessary PLMN, such as, for example, a maximum of six (own PLMN+5 others), needs to be signaled. 
     As shown in  FIG. 1 , PLMN identity is coded, in approximately 12 bytes total, in 3GPP TS 36.331, section 6.3.4. In the worst case scenario for network sharing, the network would need to signal 6 PLMN identities, which equate to 6×12 bytes, totaling 72 bytes. 
     Complementing the LTE platform with unlicensed spectrum is a possible choice under the above considerations. It would enable operators and vendors to leverage the existing or planned investments in LTE/evolved packet core (EPC) hardware in the radio and core network, especially if “Licensed-Assisted Access” is considered a secondary component carrier integrated into LTE. 
     SUMMARY 
     According to certain embodiments, a method may include preparing information related to a carrier and/or cell operating on a non-licensed spectrum. The method may also include providing, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum. 
     According to other embodiments, a method may include receiving, at a user equipment, information from a network element operating on a licensed spectrum. The method may also include processing the information. In certain embodiments, the information may be related to a carrier and/or cell operating on a non-licensed spectrum. 
     An apparatus, according to certain embodiments, may include at least one processor, and at least one memory including computer program code. The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus at least to prepare information related to a carrier and/or cell operating on a non-licensed spectrum. The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to provide, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum. 
     An apparatus, according to other embodiments, may include at least one processor, and at least one memory including computer program code. The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus at least to receive, at a user equipment, information from a network element operating on a licensed spectrum. The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to process the information. In certain embodiments, the information may be related to a carrier and/or cell operating on a non-licensed spectrum. 
     According to certain embodiments, a computer program may be embodied on a non-transitory computer readable medium. The computer program, when executed by a processor, may cause the processor at least to prepare information related to a carrier and/or cell operating on a non-licensed spectrum. The computer program, when executed by a processor, may also cause the processor at least to provide, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum. 
     According to other embodiments, a computer program may be embodied on a non-transitory computer readable medium. The computer program, when executed by a processor, may cause the processor at least to receive, at a user equipment, information from a network element operating on a licensed spectrum. The computer program, when executed by a processor, may also cause the processor at least to process the information. In certain embodiments, the information may be related to a carrier and/or cell operating on a non-licensed spectrum. 
     An apparatus, according to certain embodiments, may include means for preparing information related to a carrier and/or cell operating on a non-licensed spectrum. The apparatus may also include means for providing, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum. 
     An apparatus according to other embodiments, may include means for receiving, at a user equipment, information from a network element operating on a licensed spectrum. The apparatus may also include means for processing the information. In certain embodiments, the information may be related to a carrier and/or cell operating on a non-licensed spectrum. 
     A computer program product may, in certain embodiments, encode instructions for performing a process. The process may include preparing information related to a carrier and/or cell operating on a non-licensed spectrum. The process may also include providing, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum. 
     A computer program product may, in other embodiments, encode instructions for performing a process. The process may include receiving, at a user equipment, information from a network element operating on a licensed spectrum. The process may also include processing the information. In certain embodiments, the information may be related to a carrier and/or cell operating on a non-licensed spectrum. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For proper understanding of the invention, reference should be made to the accompanying drawings, wherein: 
         FIG. 1  illustrates coding of a PLMN-identity information element. 
         FIG. 2  illustrates a system according to certain embodiments. 
         FIG. 3  illustrates a method according to certain embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     According to certain embodiments, information signaling for network sharing may be signaled, in broadcast and/or a dedicated manner, via a cell or system operating on the licensed spectrum. For example, in certain embodiments, a cell or system on the licensed spectrum may provide, via broadcast and/or dedicating signaling, information related to carrier and/or cell(s) on the non-licensed spectrum. 
     The information may include, for example: (1) information relevant when evaluating if a user equipment (UE) is allowed to access a cell and the scheduling of other system information; (2) radio resource configuration information; (3) cell re-selection and measurement reporting and measurement information common for intra-frequency, inter-frequency and/or inter-radio access technology (RAT) mobility; (4) relevant identity related information, such as, for example, physical cell identity (PCI), cell global identity (CGI), PLMN, frequency, and routing area update (RAU)/tracking area update (TAU)/location area update (LAU); (5) the information required to acquire multimedia broadcast multicast services (MBMS) control information associated with one or more multicast-broadcast single-frequency network (MBSFN) areas; (6) extended access class barring parameters; and (7) information relevant for traffic steering between evolved universal terrestrial radio access network (E-UTRAN), on an unlicensed spectrum, and wireless local area network (WLAN). 
     As a simple illustration, PLMN is described as an example of the information signaling for network sharing in the various embodiments described below, without limitation. 
     According to other embodiments, PLMN signaling for network sharing may be signaled, in a broadcast and/or dedicated manner, via a cell operating on the licensed spectrum. For example, a primary cell (Pcell) may signal a list of PLMNs operating on an unlicensed spectrum for network sharing. The UE may assume only cells belonging to the list of PLMNs are present, and may access any cell on the LTE-U band if there is a match between the list of PLMNs according to the UE&#39;s access rules. 
     Further, according to certain embodiments, PLMN signaling network sharing may be signaled, in a broadcast and/or a dedicated manner, via a cell operating on the licensed spectrum. In such a case, the PLMN information may be broadcasted in the cell on the LTE-U band in a time divided manner. For example, if two PLMNs share the same RAN in LTE-U, PLMN1 information may be broadcasted at different time intervals than PLMN2 information. 
     According to other embodiments, only a fraction of the PLMN information may be broadcasted in the LTE-U band. The fraction of the PLMN identity may refer to one of the PLMNs&#39; broadcast on the licensed band in a system information block (SIB) from where the complete PLMN supported in the LTE-U band can be derived. Additionally, in other embodiments, a combination of any of the above-described signaling and broadcast options may be applied in PLMN signaling for network sharing that is signaled via a cell or system operating on the licensed spectrum. 
     In certain embodiments, PLMN identities may be signaled, in a broadcast and/or in a dedicated manner, with a corresponding index on a cell operating on a licensed spectrum. In other embodiments, only the index, which maps to the PLMN given, may be signaled on the cell operating on the unlicensed spectrum. 
     Additionally, according to certain embodiments, on the unlicensed spectrum, only a limited number of PLMNs may be broadcasted at the same transmission occasion. In particular, a number of broadcasted PLMNs may be indicated. For example, if there is an enhanced system information block (eSIB) broadcast on LAA with a periodicity of 40 ms, then every other eSIB could have a partial amount of PLMNs. In certain embodiments the partial amount of PLMNs may be approximately half the number of PLMNs. 
     Furthermore, according to other embodiments, there may be an indication that not all PLMNs are in one eSIB. This could be, for example, a bit or “index of eSIB” indicating which order number the SIB is. 
     According to certain embodiments, it may be assumed that LTE-U/LAA will utilize LTE carrier aggregation configurations and architecture where a (lower-power) secondary cell (Scell) operates in the unlicensed spectrum, and is either downlink (DL)-only or contains uplink (UL) and DL, and where the Pcell operates in the licensed spectrum and may be either LTE frequency division duplex (FDD) or LTE time division duplex (TDD). It may also be assumed that the LTE-U/LAA cell will transmit/broadcast system information and/or discovery signals consisting of, for example, PCI, PLMN, CGI, system frame number (SFN) timing, access parameters, LBT parameters etc. 
     Additionally, there may be several options for enabling network sharing for a cell, such as an Scell, operating on an unlicensed spectrum. As one option, a cell, such as a Pcell on a licensed spectrum may signal, via dedicated and/or broadcast signaling, a list of PLMNs for network sharing in an unlicensed spectrum. However, in order for the UE to understand which cell belongs to which PLMN on LAA, information for which cell the PLMN information is valid can also be included. The cell may also indicate for which PCI(s), such as for example, range of PCIs, indicated PLMN(s) are valid. 
     As a second option, a cell, such as a Pcell on a licensed spectrum may signal, via dedicated and/or broadcast signaling, a list of PLMNs with an index, or other common identifier, for network sharing. Further, a cell, such as an Scell on an unlicensed spectrum may broadcast only the index instead of the PLMN ID. In this case, the UE would be able to determine the PLMN based on the index provided. 
     As a third option, a cell, such as an Scell on an unlicensed spectrum may broadcast PLMNs in a changing manner. For example, the broadcasted PLMN may be different in different transmission occasions, including a limited number, such as, for example, one or two, etc., PLMNs may be broadcasted at a time. In addition, a number of broadcasted PLMNs could be indicated. For example, if there is eSIB broadcast on LAA with periodicity of 40 ms, then every other eSIB could have a partial amount of PLMNs, such as, for example, approximately half of the PLMNs. Further, there may be an indication that not all PLMNs are in one eSIB. This may be, for example, a bit or “index of eSIB” indicating which order number the SIB is. Alternatively, the full, or partly, PLMN information may be broadcasted on an LTE-U cell, such as, for example, in eSIB or detection signal, in a TDD manner. 
     The above-described embodiments may provide distinct advantages. For example, according to certain embodiments, it may be possible to optimize signaling for LTE-U/LAA. Further, according to other embodiments, it may be possible to have RAN/network sharing. 
       FIG. 2  illustrates a system according to certain embodiments of the invention. In one embodiment, a system may include multiple devices, such as, for example, at least one evolved node B (eNB)  210  or a base station or access point, and at least one UE  220 . According to certain embodiments, the UE may include any terminal device, such as, for example, a sensor, a smart meter, a personal digital assistant (PDA), smart phone, laptop computer, tablet computer, computer terminals and/or network devices. 
     Each of these devices may include at least one processor, respectively indicated as  214  and  224 . At least one memory may be provided in each device, and indicated as  215  and  225 , respectively. The memory may include computer program instructions or computer code contained therein. The processors  214  and  224 , and memories  215  and  225 , or a subset thereof, may be configured to provide means corresponding to the various blocks of  FIG. 3 . 
     As shown in  FIG. 2 , transceivers  216  and  226  may be provided, and each device may also include an antenna, respectively illustrated as  217  and  227 . Transceivers  216  and  226  may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit device that is configured both for transmission and reception. 
     Processors  214  and  224  may be embodied by any computational or data processing device, such as a central processing unit (CPU), application specific integrated circuit (ASIC), or comparable device. The processor may be implemented as a single controller, or a plurality of controllers or processors. 
     Memories  215  and  225  may be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate from the one or more processors. Furthermore, the computer program instructions stored in the memory and which may be processed by the processors may be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. 
     The memory and computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as eNB  210  and UE  220 , to perform any of the processes described herein (see, for example,  FIG. 3 ). Therefore, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions that, when executed in hardware, perform a process such as one of the processes described herein. Alternatively, certain embodiments of the invention may be performed entirely in hardware. 
     Furthermore, although  FIG. 2  illustrates a system including an eNB  210  and UE  220 , embodiments of the invention may be applicable to other configurations, and configurations involving additional elements. For example, not shown, additional UEs and/or eNBs may be present. 
       FIG. 3  illustrates a method according to certain embodiments. As shown in  FIG. 3 , a method may include, at  310 , preparing the information. The information may be related to a carrier and/or cell operating on a non-licensed spectrum. The method may also include at  320 , providing, from a network element operating on a licensed spectrum to a user equipment, the information related to the carrier and/or cell operating on the non-licensed spectrum. In certain embodiments, the network element may include an eNB, base station or access point. 
       FIG. 3  also illustrates a method that may include, at  330 , receiving, at a user equipment, information from a network element. The network element may be operating on a licensed spectrum. The method may also include at  340 , processing the information. In certain embodiments, the information may be related to a carrier and/or cell operating on a non-licensed spectrum. 
     It will be readily understood that the components of the invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the above detailed description of the embodiments of systems, methods, apparatuses, and computer program products for network sharing for LTE-U/LAA cells operating on unlicensed spectrum, as represented in the attached figures, is not intended to limit the scope of the invention, but is merely representative of selected embodiments of the invention. 
     The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases “certain embodiments,” “some embodiments,” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearances of the phrases “in certain embodiments,” “in some embodiments,” “in other embodiments,” or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     Additionally, if desired, the different functions discussed above may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the described functions may be optional or may be combined. As such, the above description should be considered as merely illustrative of the principles, teachings and embodiments of this invention, and not in limitation thereof. 
     One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims. 
     Glossary 
     3GPP Third Generation Partnership Project 
     ASIC Application Specific Integrated Circuit 
     CGI Cell Global Identity 
     CPU Central Processing Unit 
     CRS Common Reference Signal 
     DL Downlink 
     eNB Evolved Node B 
     EPC Evolved Packet Core 
     eSIB Enhanced Signal Information Block 
     E-UTRAN Evolved Universal Terrestrial Radio Access Network 
     FDD Frequency Division Duplex 
     HDD Hard Disk Drive 
     ID Identification 
     IMT International Mobile Telecommunications 
     LAA Licensed Assisted Access 
     LAU Location Area Update 
     LBT Listen Before Talk 
     LTE Long Term Evolution (a.k.a., E-UTRA) 
     LTE-U LTE on Unlicensed Band 
     MBMS Multimedia Broadcast Multicast Services 
     MBSFN Multicast-Broadcast Single-Frequency Network 
     Pcell Primary Cell 
     PDA Personal Digital Assistant 
     PCI Physical Cell Identity 
     PLMN Public Land Mobile Network 
     PSS Primary Synchronization Channel 
     RAM Random Access Memory 
     RAN Radio Access Network 
     RAT Radio Access Technology 
     RAU Routing Area Update 
     Scell Secondary Cell 
     SFN System Frame Number 
     SIB System Information Block 
     SSS Secondary Synchronization Channel 
     TAU Tracking Area Update 
     TDD Time Division Duplex 
     UE User Equipment 
     UL Uplink 
     WLAN Wireless Local Area Network