WO2013169394A2 - Carrier aggregation capable mobile operation over single frequency - Google Patents

Carrier aggregation capable mobile operation over single frequency Download PDF

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Publication number
WO2013169394A2
WO2013169394A2 PCT/US2013/032557 US2013032557W WO2013169394A2 WO 2013169394 A2 WO2013169394 A2 WO 2013169394A2 US 2013032557 W US2013032557 W US 2013032557W WO 2013169394 A2 WO2013169394 A2 WO 2013169394A2
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WO
WIPO (PCT)
Prior art keywords
target cell
primary serving
serving cell
cell
target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/US2013/032557
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English (en)
French (fr)
Other versions
WO2013169394A3 (en
Inventor
Tingfang Ji
Durga Prasad Malladi
Yongbin Wei
Wanshi Chen
Rajat Prakash
Peter Gaal
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Qualcomm Inc
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Qualcomm Inc
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Publication date
Application filed by Qualcomm Inc filed Critical Qualcomm Inc
Priority to CN201380024253.6A priority Critical patent/CN104272835A/zh
Priority to EP13715813.5A priority patent/EP2848060A2/en
Priority to JP2015511468A priority patent/JP2015516777A/ja
Publication of WO2013169394A2 publication Critical patent/WO2013169394A2/en
Publication of WO2013169394A3 publication Critical patent/WO2013169394A3/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A) or DMT
    • H04L5/001—Time-frequency the frequencies being orthogonal, e.g. OFDM(A) or DMT the frequencies being arranged in component carriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
    • H04W36/0085—Hand-off measurements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/309—Measuring or estimating channel quality parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/382—Monitoring; Testing of propagation channels for resource allocation, admission control or handover
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0091—Signalling for the administration of the divided path, e.g. signalling of configuration information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0058—Transmission of hand-off measurement information, e.g. measurement reports
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0069—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink
    • H04W36/00692—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signalling, i.e. of overhead other than pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signalling, i.e. of overhead other than pilot signals
    • H04L5/0057—Physical resource allocation for CQI

Definitions

  • the present disclosure relates generally to communication systems, and more particularly, to managing mobility of a mobile terminal configured for carrier aggregation over two cells on a same frequency.
  • Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts.
  • Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power).
  • multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD- SCDMA) systems.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD- SCDMA time division synchronous code division multiple access
  • LTE Long Term Evolution
  • UMTS Universal Mobile Telecommunications System
  • 3 GPP Third Generation Partnership Project
  • UMTS Universal Mobile Telecommunications System
  • DL downlink
  • UL uplink
  • MIMO multiple-input multiple-output
  • carrier aggregation may not offer a performance gain.
  • Carrier aggregation may be disabled when spectrum or infrastructure for a supported carrier aggregation band combination is not available. As such, alternative ways of implementing a carrier aggregation scheme are needed to realize performance benefits.
  • the UE when the UE is configured for carrier aggregation over two cells on a same frequency, and the UE communicates with each cell via a respective radio tuned to the same frequency, the UE may utilize the two radios to enhance performance.
  • the UE may utilize the two radios of the carrier aggregation scheme to implement a coordinated multipoint (CoMP) scheme if base stations of a corresponding network have a fast or high throughput backhaul topology.
  • the UE may utilize the two radios of the carrier aggregation scheme to enhance mobility from one cell to another.
  • CoMP coordinated multipoint
  • a method, an apparatus, and a computer program product for wireless communication communicates with a primary serving cell via a first radio, detects a presence of a target cell, sends a first message to the primary serving cell indicating the detected presence of the target cell, receives a command from the primary serving cell to add the target cell as a secondary serving cell, and communicates with at least one of the primary serving cell or the target cell via a second radio to facilitate a handover to the target cell, wherein the first radio and the second radio operate on a same frequency, a downlink control channel of the primary serving cell is not used to schedule a target cell downlink transmission, an uplink control channel to the primary serving cell is not used to provide an acknowledgment of the target cell downlink transmission, and the uplink control channel to the primary serving cell is not used to provide channel side information for the target cell downlink transmission.
  • the apparatus communicates with a user equipment (UE) via a first radio at a primary serving cell, communicates with the UE via a second radio at a target cell, receives, at the primary serving cell, a first message from the UE indicating a detected presence of the target cell, and sends a second message from the primary serving cell to the UE, the second message including a command to add the target cell as a secondary serving cell, wherein a downlink control channel of the primary serving cell is not used to schedule a target cell downlink transmission, an uplink control channel to the primary serving cell is not used to provide an acknowledgment of the target cell downlink transmission, and the uplink control channel to the primary serving cell is not used to provide channel side information for the target cell downlink transmission.
  • UE user equipment
  • the apparatus sends a capability message to at least one of a primary serving cell or a secondary serving cell, the capability message indicating a capability of communicating via a first component carrier and a second component carrier operating on a same frequency, communicates with the primary serving cell via the first component carrier, communicates with the secondary serving cell via the second component carrier, and receives data samples from both the primary serving cell and the secondary serving cell.
  • the apparatus communicates with a primary serving cell via a single radio, and communicates with a target cell via the single radio to facilitate a handover to the target cell, wherein the communication with the primary serving cell is time-division multiplexed with the communication with the target cell, a downlink control channel of the primary serving cell is not used to schedule a target cell downlink transmission, an uplink control channel to the primary serving cell is not used to provide an acknowledgment of the target cell downlink transmission, and the uplink control channel to the primary serving cell is not used to provide channel side information for the target cell downlink transmission.
  • the apparatus communicates with a user equipment (UE) via a single radio at a primary serving cell, communicates with the UE via the single radio at a target cell, receives, at the primary serving cell, a first message from the UE indicating a detected presence of the target cell, and sends a second message from the primary serving cell to the UE, the second message including a request to report channel quality information (CQI) related to the primary serving cell and the target cell, wherein the communication with the UE at the primary serving cell is time-division multiplexed with the communication with the UE at the target cell.
  • CQI channel quality information
  • FIG. 1 is a diagram illustrating an example of a network architecture.
  • FIG. 2 is a diagram illustrating an example of an access network.
  • FIG. 3 is a diagram illustrating an example of a DL frame structure in LTE.
  • FIG. 4 is a diagram illustrating an example of an UL frame structure in LTE.
  • FIG. 5 is a diagram illustrating an example of a radio protocol architecture for the user and control planes.
  • FIG. 6 is a diagram illustrating an example of an evolved Node B and user equipment in an access network.
  • FIG. 7 is a diagram illustrating a range expanded cellular region in a heterogeneous network.
  • FIG. 8 is a diagram illustrating a UE mobility procedure.
  • FIG. 9 is a diagram illustrating a UE mobility procedure incorporating a carrier aggregation scheme.
  • FIG. 10 is a diagram illustrating a UE mobility procedure incorporating a carrier aggregation scheme.
  • FIG. 11 is a diagram illustrating a UE mobility procedure incorporating a carrier aggregation scheme.
  • FIG. 12 is a diagram illustrating a UE mobility procedure incorporating a carrier aggregation scheme.
  • FIG. 13 is a flow chart of a method of wireless communication.
  • FIG. 14 illustrates flow charts of methods of wireless communication.
  • FIG. 15 is a flow chart of a method of wireless communication.
  • FIG. 16 illustrates flow charts of methods of wireless communication.
  • FIG. 17 is a flow chart of a method of wireless communication.
  • FIG. 18 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus.
  • FIG. 19 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus.
  • FIG. 20 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.
  • FIG. 21 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.
  • 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 functionality described throughout this disclosure.
  • DSPs digital signal processors
  • FPGAs field programmable gate arrays
  • PLDs programmable logic devices
  • state machines gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality 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 functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium.
  • Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer.
  • such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
  • Disk and disc includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), and floppy disk where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
  • FIG. 1 is a diagram illustrating an LTE network architecture 100.
  • the LTE network architecture 100 may be referred to as an Evolved Packet System (EPS) 100.
  • the EPS 100 may include one or more user equipment (UE) 102, an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) 104, an Evolved Packet Core (EPC) 110, a Home Subscriber Server (HSS) 120, and an Operator's Internet Protocol (IP) Services 122.
  • the EPS can interconnect with other access networks, but for simplicity those entities/interfaces are not shown.
  • the EPS provides packet-switched services, however, as those skilled in the art will readily appreciate, the various concepts presented throughout this disclosure may be extended to networks providing circuit-switched services.
  • the E-UTRAN includes the evolved Node B (eNB) 106 and other eNBs 108.
  • eNB evolved Node B
  • the eNB 106 provides user and control planes protocol terminations toward the UE 102.
  • the eNB 106 may be connected to the other eNBs 108 via a backhaul (e.g., an X2 interface).
  • the eNB 106 may also be referred to as a base station, a Node B, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), or some other suitable terminology.
  • the eNB 106 provides an access point to the EPC 110 for a UE 102.
  • Examples of UEs 102 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, or any other similar functioning device.
  • SIP session initiation protocol
  • PDA personal digital assistant
  • satellite radio a global positioning system
  • multimedia device e.g., a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, or any other similar functioning device.
  • MP3 player digital audio player
  • the UE 102 may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.
  • the eNB 106 is connected to the EPC 110.
  • the EPC 1 10 includes a Mobility
  • MME Management Entity
  • MBMS Multimedia Broadcast Multicast Service
  • BM-SC Broadcast Multicast Service Center
  • PDN Packet Data Network Gateway 118.
  • the MME 112 is the control node that processes the signaling between the UE 102 and the EPC 1 10. Generally, the MME 112 provides bearer and connection management. All user IP packets are transferred through the Serving Gateway 1 16, which itself is connected to the PDN Gateway 1 18.
  • the PDN Gateway 1 18 provides UE IP address allocation as well as other functions.
  • the PDN Gateway 118 is connected to the Operator's IP Services 122.
  • the Operator's IP Services 122 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), and a PS Streaming Service (PSS).
  • the BM-SC 126 may provide functions for MBMS user service provisioning and delivery.
  • the BM-SC 126 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a PLMN, and may be used to schedule and deliver MBMS transmissions.
  • the MBMS Gateway 124 may be used to distribute MBMS traffic to the eNBs (e.g., 106, 108) belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.
  • MMSFN Multicast Broadcast Single Frequency Network
  • FIG. 2 is a diagram illustrating an example of an access network 200 in an LTE network architecture.
  • the access network 200 is divided into a number of cellular regions (cells) 202.
  • One or more lower power class eNBs 208 may have cellular regions 210 that overlap with one or more of the cells 202.
  • the lower power class eNB 208 may be a femto cell (e.g., home eNB (HeNB)), pico cell, micro cell, or remote radio head (RRH).
  • HeNB home eNB
  • RRH remote radio head
  • the macro eNBs 204 are each assigned to a respective cell 202 and are configured to provide an access point to the EPC 110 for all the UEs 206 in the cells 202.
  • the eNBs 204 are responsible for all radio related functions including radio bearer control, admission control, mobility control, scheduling, security, and connectivity to the serving gateway 116.
  • An eNB may support one or multiple (e.g., three) cells (also referred to as a sector).
  • the term "cell” can refer to the smallest coverage area of an eNB and/or an eNB subsystem serving are particular coverage area. Further, the terms “eNB,” “base station,” and “cell” may be used interchangeably herein.
  • OFDM frequency division duplex
  • TDD time division duplex
  • EV-DO Evolution-Data Optimized
  • UMB Ultra Mobile Broadband
  • EV-DO and UMB are air interface standards promulgated by the 3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and employs CDMA to provide broadband Internet access to mobile stations. These concepts may also be extended to Universal Terrestrial Radio Access (UTRA) employing Wideband- CDMA (W-CDMA) and other variants of CDMA, such as TD-SCDMA; Global System for Mobile Communications (GSM) employing TDMA; and Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash- OFDM employing OFDMA.
  • UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from the 3 GPP organization.
  • CDMA2000 and UMB are described in documents from the 3GPP2 organization. The actual wireless communication standard and the multiple access technology employed will depend on the specific application and the overall design constraints imposed on the system.
  • the eNBs 204 may have multiple antennas supporting MIMO technology.
  • MIMO technology enables the eNBs 204 to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity.
  • Spatial multiplexing may be used to transmit different streams of data simultaneously on the same frequency.
  • the data streams may be transmitted to a single UE 206 to increase the data rate or to multiple UEs 206 to increase the overall system capacity. This is achieved by spatially precoding each data stream (i.e., applying a scaling of an amplitude and a phase) and then transmitting each spatially precoded stream through multiple transmit antennas on the DL.
  • the spatially precoded data streams arrive at the UE(s) 206 with different spatial signatures, which enables each of the UE(s) 206 to recover the one or more data streams destined for that UE 206.
  • each UE 206 transmits a spatially precoded data stream, which enables the eNB 204 to identify the source of each spatially precoded data stream.
  • Spatial multiplexing is generally used when channel conditions are good. When channel conditions are less favorable, beamforming may be used to focus the transmission energy in one or more directions. This may be achieved by spatially precoding the data for transmission through multiple antennas. To achieve good coverage at the edges of the cell, a single stream beamforming transmission may be used in combination with transmit diversity. [0045] In the detailed description that follows, various aspects of an access network will be described with reference to a MIMO system supporting OFDM on the DL.
  • OFDM is a spread-spectrum technique that modulates data over a number of subcarriers within an OFDM symbol. The subcarriers are spaced apart at precise frequencies. The spacing provides "orthogonality" that enables a receiver to recover the data from the subcarriers.
  • a guard interval (e.g., cyclic prefix) may be added to each OFDM symbol to combat inter-OFDM-symbol interference.
  • the UL may use SC-FDMA in the form of a DFT-spread OFDM signal to compensate for high peak-to-average power ratio (PAPR).
  • PAPR peak-to-average power ratio
  • FIG. 3 is a diagram 300 illustrating an example of a DL frame structure in LTE.
  • a frame (10 ms) may be divided into 10 equally sized subframes. Each subframe may include two consecutive time slots.
  • a resource grid may be used to represent two time slots, each time slot including a resource block.
  • the resource grid is divided into multiple resource elements.
  • a resource block contains 12 consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each OFDM symbol, 7 consecutive OFDM symbols in the time domain, or 84 resource elements.
  • For an extended cyclic prefix a resource block contains 6 consecutive OFDM symbols in the time domain and has 72 resource elements.
  • Some of the resource elements, indicated as R 302, 304, include DL reference signals (DL-RS).
  • the DL-RS include Cell-specific RS (CRS) (also sometimes called common RS) 302 and UE-specific RS (UE-RS) 304.
  • UE-RS 304 are transmitted only on the resource blocks upon which the corresponding physical DL shared channel (PDSCH) is mapped.
  • PDSCH physical DL shared channel
  • the number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks that a UE receives and the higher the modulation scheme, the higher the data rate for the UE.
  • FIG. 4 is a diagram 400 illustrating an example of an UL frame structure in
  • the available resource blocks for the UL may be partitioned into a data section and a control section.
  • the control section may be formed at the two edges of the system bandwidth and may have a configurable size.
  • the resource blocks in the control section may be assigned to UEs for transmission of control information.
  • the data section may include all resource blocks not included in the control section.
  • the UL frame structure results in the data section including contiguous subcarriers, which may allow a single UE to be assigned all of the contiguous subcarriers in the data section.
  • a UE may be assigned resource blocks 410a, 410b in the control section to transmit control information to an eNB.
  • the UE may also be assigned resource blocks 420a, 420b in the data section to transmit data to the eNB.
  • the UE may transmit control information in a physical UL control channel (PUCCH) on the assigned resource blocks in the control section.
  • the UE may transmit only data or both data and control information in a physical UL shared channel (PUSCH) on the assigned resource blocks in the data section.
  • a UL transmission may span both slots of a subframe and may hop across frequency.
  • a set of resource blocks may be used to perform initial system access and achieve UL synchronization in a physical random access channel (PRACH) 430.
  • the PRACH 430 carries a random sequence and cannot carry any UL data/signaling.
  • Each random access preamble occupies a bandwidth corresponding to six consecutive resource blocks.
  • the starting frequency is specified by the network. That is, the transmission of the random access preamble is restricted to certain time and frequency resources. There is no frequency hopping for the PRACH.
  • the PRACH attempt is carried in a single subframe (1 ms) or in a sequence of few contiguous subframes and a UE can make only a single PRACH attempt per frame (10 ms).
  • FIG. 5 is a diagram 500 illustrating an example of a radio protocol architecture for the user and control planes in LTE.
  • the radio protocol architecture for the UE and the eNB is shown with three layers: Layer 1, Layer 2, and Layer 3.
  • Layer 1 (LI layer) is the lowest layer and implements various physical layer signal processing functions.
  • the LI layer will be referred to herein as the physical layer 506.
  • Layer 2 (L2 layer) 508 is above the physical layer 506 and is responsible for the link between the UE and eNB over the physical layer 506.
  • the L2 layer 508 includes a media access control (MAC) sublayer 510, a radio link control (RLC) sublayer 512, and a packet data convergence protocol (PDCP) 514 sublayer, which are terminated at the eNB on the network side.
  • MAC media access control
  • RLC radio link control
  • PDCP packet data convergence protocol
  • the UE may have several upper layers above the L2 layer 508 including a network layer (e.g., IP layer) that is terminated at the PDN gateway 1 18 on the network side, and an application layer that is terminated at the other end of the connection (e.g., far end UE, server, etc.).
  • the PDCP sublayer 514 provides multiplexing between different radio bearers and logical channels.
  • the PDCP sublayer 514 also provides header compression for upper layer data packets to reduce radio transmission overhead, security by ciphering the data packets, and handover support for UEs between eNBs.
  • the RLC sublayer 512 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to hybrid automatic repeat request (HARQ).
  • HARQ hybrid automatic repeat request
  • the MAC sublayer 510 provides multiplexing between logical and transport channels. The MAC sublayer 510 is also responsible for allocating the various radio resources (e.g., resource blocks) in one cell among the UEs. The MAC sublayer 510 is also responsible for HARQ operations.
  • the radio protocol architecture for the UE and eNB is substantially the same for the physical layer 506 and the L2 layer 508 with the exception that there is no header compression function for the control plane.
  • the control plane also includes a radio resource control (RRC) sublayer 516 in Layer 3 (L3 layer).
  • RRC sublayer 516 is responsible for obtaining radio resources (e.g., radio bearers) and for configuring the lower layers using RRC signaling between the eNB and the UE.
  • FIG. 6 is a block diagram of an eNB 610 in communication with a UE 650 in an access network.
  • upper layer packets from the core network are provided to a controller/processor 675.
  • the controller/processor 675 implements the functionality of the L2 layer.
  • the controller/processor 675 provides header compression, ciphering, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocations to the UE 650 based on various priority metrics.
  • the controller/processor 675 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the UE 650.
  • the transmit (TX) processor 616 implements various signal processing functions for the LI layer (i.e., physical layer).
  • the signal processing functions include coding and interleaving to facilitate forward error correction (FEC) at the UE 650 and mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase- shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)).
  • FEC forward error correction
  • BPSK binary phase-shift keying
  • QPSK quadrature phase-shift keying
  • M-PSK M-phase- shift keying
  • M-QAM M-quadrature amplitude modulation
  • Each stream is then mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream.
  • the OFDM stream is spatially precoded to produce multiple spatial streams.
  • Channel estimates from a channel estimator 674 may be used to determine the coding and modulation scheme, as well as for spatial processing.
  • the channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 650.
  • Each spatial stream may then be provided to a different antenna 620 via a separate transmitter 618TX.
  • Each transmitter 618TX may modulate an RF carrier with a respective spatial stream for transmission.
  • each receiver 654RX receives a signal through its respective antenna 652. Each receiver 654RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 656.
  • the RX processor 656 implements various signal processing functions of the LI layer. The RX processor 656 may perform spatial processing on the information to recover any spatial streams destined for the UE 650. If multiple spatial streams are destined for the UE 650, they may be combined by the RX processor 656 into a single OFDM symbol stream. The RX processor 656 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT).
  • FFT Fast Fourier Transform
  • the frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal.
  • the symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the eNB 610. These soft decisions may be based on channel estimates computed by the channel estimator 658.
  • the soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNB 610 on the physical channel.
  • the data and control signals are then provided to the controller/processor 659.
  • the controller/processor 659 implements the L2 layer.
  • the controller/processor can be associated with a memory 660 that stores program codes and data.
  • the memory 660 may be referred to as a computer-readable medium.
  • the controller/processor 659 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover upper layer packets from the core network.
  • the upper layer packets are then provided to a data sink 662, which represents all the protocol layers above the L2 layer.
  • Various control signals may also be provided to the data sink 662 for L3 processing.
  • the controller/processor 659 is also responsible for error detection using an acknowledgement (ACK) and/or negative acknowledgement (ACK) protocol to support HARQ operations.
  • ACK acknowledgement
  • ACK negative acknowledgement
  • a data source 667 is used to provide upper layer packets to the controller/processor 659.
  • the data source 667 represents all protocol layers above the L2 layer.
  • the controller/processor 659 implements the L2 layer for the user plane and the control plane by providing header compression, ciphering, packet segmentation and reordering, and multiplexing between logical and transport channels based on radio resource allocations by the eNB 610.
  • the controller/processor 659 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the eNB 610.
  • Channel estimates derived by a channel estimator 658 from a reference signal or feedback transmitted by the eNB 610 may be used by the TX processor 668 to select the appropriate coding and modulation schemes, and to facilitate spatial processing.
  • the spatial streams generated by the TX processor 668 may be provided to different antenna 652 via separate transmitters 654TX. Each transmitter 654TX may modulate an RF carrier with a respective spatial stream for transmission.
  • the UL transmission is processed at the eNB 610 in a manner similar to that described in connection with the receiver function at the UE 650.
  • Each receiver 618RX receives a signal through its respective antenna 620.
  • Each receiver 618RX recovers information modulated onto an RF carrier and provides the information to a RX processor 670.
  • the RX processor 670 may implement the LI layer.
  • the controller/processor 675 implements the L2 layer.
  • the controller/processor 675 can be associated with a memory 676 that stores program codes and data.
  • the memory 676 may be referred to as a computer-readable medium.
  • the control/processor 675 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover upper layer packets from the UE 650.
  • Upper layer packets from the controller/processor 675 may be provided to the core network.
  • the controller/processor 675 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.
  • FIG. 7 is a diagram 700 illustrating a range expanded cellular region in a heterogeneous network.
  • a lower power class eNB such as the RRH 710b may have a range expanded cellular region 703 that is expanded from the cellular region 702 through enhanced inter-cell interference coordination between the RRH 710b and the macro eNB 710a and through interference cancelation performed by the UE 720.
  • the RRH 710b receives information from the macro eNB 710a regarding an interference condition of the UE 720.
  • the information allows the RRH 710b to serve the UE 720 in the range expanded cellular region 703 and to accept a handoff of the UE 720 from the macro eNB 710a as the UE 720 enters the range expanded cellular region 703.
  • Carrier aggregation is a popular feature among network operators with fragmented spectrum to achieve a higher peak data rate.
  • Coordinated multipoint may provide better network spectral efficiency through the use of inter- node coordination, especially for remote radio head (RRH) deployments.
  • Enhanced inter-cell interference coordination elCIC
  • elCIC enables interference mitigation between macro and pico/RRH, which leads to cell range expansion and more robust mobility performance. Accordingly, a UE may benefit from combining various features of the above-described schemes.
  • a configured set of serving cells for a UE comprises one primary serving cell (PCell) and one or more secondary serving cells (SCells).
  • PCell may be defined as a cell that is initially configured during connection establishment.
  • SCell is a cell that may be configured after connection establishment, such as to provide additional radio resources.
  • the usage of uplink resources by the UE in addition to the downlink resources is configurable.
  • the number of downlink secondary component carriers (SCCs) configured may be larger than or equal to the number of uplink SCCs, and no SCell may be configured for usage of uplink resources only. From a UE viewpoint, each uplink resource belongs to one serving cell.
  • SCCs downlink secondary component carriers
  • the number of serving cells that can be configured may depend on aggregation capability of the UE.
  • a PCell may be changed via a handover procedure (i.e., with a security key change and RACH procedure).
  • the PCell may be used for transmitting PUCCH.
  • a PCell may not be deactivated. Re-establishment may be triggered when the PCell communication link experiences radio link failure (RLF), not when SCell links experience RLF.
  • RLF radio link failure
  • NAS Non-access stratum
  • the reconfiguration, addition, and removal of SCells may be performed by RRC.
  • RRC can also add, remove, or reconfigure SCells for usage with the target PCell.
  • dedicated RRC signaling may be used for sending system information of the SCell. For example, while in connected mode, a UE need not acquire broadcasted system information from the SCells.
  • LTE Rel-8/9 DRX may apply whenever a UE is configured with only one serving cell (e.g., a PCell). In other cases, the same DRX operation applies to all configured and activated serving cells (e.g., identical active time for PDCCH monitoring).
  • PDCCH or PDSCH may not transmit on the corresponding uplink, nor is the UE required to perform CQI measurements.
  • the UE may receive PDSCH and PDCCH (if the UE is configured to monitor PDCCH from the SCell), and is expected to perform CQI measurements.
  • the activation/deactivation mechanism may be based on a combination of a MAC control element and deactivation timers.
  • the MAC control element may carry a bitmap for the activation and deactivation of SCells: a bit in the bitmap set to 1 may denote activation of the corresponding SCell, while a bit in the bitmap set to 0 may denote deactivation of the corresponding SCell.
  • SCells can be activated and deactivated individually, and a single activation/deactivation command can activate/deactivate all or a subset of the SCells.
  • One deactivation timer may be maintained per SCell but one common activation/deactivation command value is configured per UE by RRC.
  • the UE may apply system information acquisition and change monitoring procedures for the PCell.
  • E-UTRAN For an SCell, E-UTRAN provides, via dedicated signaling, system information relevant for UE operation in an RRC_CO ECTED state when adding the SCell. Upon change of the relevant system information of a configured SCell, E-UTRAN releases the SCell and subsequently adds the configured SCell to the set of serving cells, which may be done with a single RRCConnectionReconfiguration message.
  • the network may control UE mobility, e.g., the network decides when the UE connects to which E-UTRA cell(s), or inter-RAT cell.
  • the current serving PCell can be changed using an RRCConnectionReconfiguration message including a mobilityControlInfo message (handover), whereas the current SCell(s) can be changed using the RRCConnectionReconfiguration message either with or without the mobilityControlInfo message.
  • the network may trigger the handover procedure, e.g., based on radio conditions or load.
  • the network may configure the UE to perform measurement reporting (possibly including the configuration of measurement gaps).
  • the network may also initiate handover blindly, e.g., without having received measurement reports from the UE.
  • carrier aggregation of multiple component carriers may be implemented to achieve high-bandwidth transmission.
  • operators with fragmented spectrum may use carrier aggregation to reach higher peak data rates.
  • carrier aggregation allows a UE to receive and transmit on two carrier frequencies.
  • UE capabilities may include: 1) connected mode only; 2) primary cell and secondary cell management (configuration, activation); 3) measurement and reporting (radio resource management (RRM), channel quality information (CQI), etc.); and 4) simultaneous decoding of PDCCH and PDSCH in the baseband.
  • UE capabilities may include: 1) intra-band radio frequency (RF) requirements (e.g., capabilities for aggregating carriers within a frequency band); and 2) inter-band RF requirements (e.g., capabilities for aggregating carriers across different frequency bands).
  • RF radio frequency
  • carrier aggregation when a network is loaded, e.g., when a peak data rate is not limited by UE capability, carrier aggregation may not offer a performance gain. Moreover, carrier aggregation may be disabled when spectrum or infrastructure for a supported carrier aggregation band combination is not available. As such, performance benefits of carrier aggregation may be limited to: 1) a peak data rate increase in lightly loaded networks at locations where carrier aggregation capable eNBs and supported carrier aggregation band combinations are available; and 2) a supplementary data carrier for opportunistic access.
  • carrier aggregation may be modified to make use of baseband capability of carrier aggregation capable UEs in all bands. Consequently, UEs not capable of carrier aggregation may find value in implementing signaling support of a modified carrier aggregation scheme.
  • UEs capable of carrier aggregation may connect to two cells on the same frequency.
  • UEs may aggregate four receive antennas to a single frequency.
  • a UE capable of carrier aggregation via two carriers may have two receive antennas configured for each carrier (a total of four receive antennas).
  • the UE may utilize all four receive antennas to receive the same frequency.
  • the UE When the UE is configured for carrier aggregation over two cells on the same frequency, the UE may also be configured for inter-band carrier aggregation and/or intra-band carrier aggregation.
  • the UE may disable simultaneous transmission via a first component carrier and a second component carrier operating on the same frequency (e.g., disable simultaneous transmission of PUSCH/PUCCH) to avoid self- interference.
  • the UE when the UE implements a single radio scheme, the UE may be capable of receiving data samples simultaneously from both a primary cell (via a first component carrier) and a secondary cell (via a second component carrier).
  • certain parameters e.g., local oscillator (LO), fast Fourier transform (FFT), etc.
  • LO local oscillator
  • FFT fast Fourier transform
  • the UE may signal such capability to the network. For example, the UE may send a capability message to the primary cell or the secondary cell indicating whether the UE is capable of communicating via the first component carrier and the second component carrier operating on the same frequency. If the UE does not have the baseband power to simultaneously receive data samples via the first component carrier and the second component carrier (e.g., simultaneous reception of PDSCH/PDCCH), the capability message may indicate that a baseband receiver is incapable of simultaneously receiving via both the first component carrier and the second component carrier.
  • the capability message may indicate that a baseband receiver is incapable of simultaneously receiving via both the first component carrier and the second component carrier.
  • the baseband receiver may be incapable of simultaneous reception via both component carriers, the UE may still receive the data samples in a non-simultaneous manner via the first component carrier and second component carrier when the data samples from the primary cell and the secondary cell are time-division multiplexed. Because the transmissions from the primary cell and the secondary cell do not overlap, the UE with a single radio can decode each cell, one at a time.
  • a time-division multiplexing (TDM) pattern may be defined between the primary cell and the secondary cell.
  • the UE when the UE is configured for carrier aggregation over two cells on the same frequency, and the UE communicates with each cell via a respective radio tuned to the same frequency, the UE may utilize the two radios to enhance performance.
  • the UE may utilize the two radios in the carrier aggregation scheme to implement a coordinated multipoint (CoMP) scheme if base stations of a corresponding network have a fast or high throughput backhaul topology.
  • the UE may utilize the two radios in the carrier aggregation scheme to enhance mobility from one cell to another.
  • CoMP coordinated multipoint
  • FIG. 8 is a diagram 800 illustrating a UE mobility procedure. Referring to FIG. 8
  • channel strength of a source cell may decrease while channel strength of a target cell (or secondary serving cell) increases as the UE moves.
  • the UE may detect a presence of the target cell.
  • an event A3 may be detected for triggering a handover operation.
  • the event A3 may be defined as the channel strength of the target cell exceeding the channel strength of the source cell by a certain amount.
  • the UE may provide a reference signal receive power (RSRP) measurement to the source cell indicating that the channel strength of the target cell exceeds the channel strength of the source cell.
  • RSRP reference signal receive power
  • the source cell may consider a handover of the UE from the source cell to the target cell, which may include a handover negotiation between the source cell and the target cell.
  • the source cell may send a handover command to the UE.
  • the UE may perform a RACH procedure with the target cell in order to establish a connection with the target cell.
  • the source cell may be considered as a secondary serving cell, or removed from a set of serving cells, while the target cell may be considered as the new primary serving cell.
  • FIG. 9 is a diagram 900 illustrating a UE mobility procedure for use with a carrier aggregation scheme.
  • the UE mobility procedure of FIG. 9 may operate with a legacy secondary serving cell (SCell).
  • SCell legacy secondary serving cell
  • the UE may communicate with the source cell (e.g., primary serving cell) via a first radio and communicate with the target cell (e.g., secondary serving cell) via a second radio, wherein the first radio and the second radio may operate on a same frequency.
  • the source cell e.g., primary serving cell
  • target cell e.g., secondary serving cell
  • FIG. 9 provides a procedure for using channel quality information (CQI) reported from the UE to improve a handover decision made at the source cell.
  • CQI channel quality information
  • FIG. 9 after the target cell is detected at time Tl (902), an event A3 may be detected (904).
  • the event A3 of FIG. 9 may be different from the event A3 of FIG. 8.
  • the event A3 may be defined as the target cell being detectable and/or measurable.
  • the event A3 of FIG. 9 may be detected not to trigger handover, but to trigger management of component carriers (e.g., primary cell/secondary cell management) in the carrier aggregation scheme.
  • component carriers e.g., primary cell/secondary cell management
  • the UE may provide a reference signal receive power (RSRP) measurement to the source cell indicating the detection of the target cell.
  • RSRP reference signal receive power
  • the source cell may send a CQI request message (e.g., Secondary cell (SCell) Add CQI config message) to the UE requesting the UE to report channel quality information (CQI) related to the source cell and CQI information related to the target cell (may be referred to herein as CQI reporting), in order for the source cell to determine downlink channel conditions.
  • CQI request message e.g., Secondary cell (SCell) Add CQI config message
  • CQI channel quality information
  • CQI reporting channel quality information
  • the UE activates the second radio to communicate with, and measure the CQI related to, the target cell.
  • the UE may send one or more CQI reports related to both the source cell and the target cell (dual CQI) allowing the source cell to determine the downlink channel conditions of both the source cell and the target cell.
  • the CQI reports related to both the source cell and the target cell may be used by the source cell to make an informed decision regarding handover of the UE from the source cell to the target cell.
  • the source cell negotiates the handover with the target cell. After the handover is agreed upon between the source cell and the target cell, the source cell may send a handover command to the UE.
  • the UE may perform a RACH procedure with the target cell to establish a connection with the target cell.
  • the source cell may be considered as a secondary serving cell, or removed from a set of serving cells, while the target cell may be considered as the new primary serving cell.
  • the handover negotiation may be started sooner to minimize failure due to the source cell link (e.g., radio link failure, poor channel quality, poor reception quality, etc.).
  • the handover negotiation may be started sooner to minimize failure at the target cell, or to minimize the chances of failure at either the source cell or the target cell.
  • FIG. 10 is a diagram 1000 illustrating another UE mobility procedure for use with a carrier aggregation scheme.
  • the UE mobility procedure of FIG. 10 provides better handover command robustness.
  • the UE may communicate with the source cell (e.g., primary serving cell) via a first radio and communicate with the target cell (e.g., secondary serving cell) via a second radio, wherein the first radio and the second radio may operate on a same frequency.
  • the procedure of FIG. 10 is similar to the procedure described above with respect to FIG. 9 except that the handover command (1002) may be sent from both the source cell and the target cell, or the target cell alone.
  • handover negotiation may start between the source cell and the target cell. Once the target cell acquires enough information, the handover may be completed by the target cell even when the source cell link fails. For example, referring to FIG. 10, at time T3 (1004), there may be a high chance of the source cell link failing, e.g., because the SNR of the link is too low. Thus, sending the handover command from the target cell (e.g., forward handover) may be desired as the target cell's increased channel strength provides a lower chance of handover failure. Sending the handover command from both the source cell and the target cell, or the target cell alone, increases the chance of the UE receiving handover information when the source cell link is prone to failure.
  • sending the handover command from the target cell e.g., forward handover
  • Sending the handover command from both the source cell and the target cell, or the target cell alone increases the chance of the UE receiving handover information when the source cell link is prone to failure.
  • FIG. 11 is a diagram 1100 illustrating another UE mobility procedure for use with a carrier aggregation scheme.
  • the UE mobility procedure of FIG. 11 improves uplink monitoring by the source cell (e.g., primary serving cell) and the target cell (e.g., secondary serving cell), thus improving a handover decision made at the source cell and/or the target cell.
  • the UE may communicate with the source cell via a first radio and communicate with the target cell via a second radio.
  • the first radio and the second radio may operate on a same frequency.
  • a UE mobility procedure is further enhanced by allowing the source cell and the target cell to actively exchange UE information, e.g., via an X2 backhaul.
  • the source cell may begin coordinating with the target cell (secondary cell (SCell)) to exchange UE information via X2 (e.g., SCell coordination).
  • SCell secondary cell
  • the source cell and target cell may exchange information to address uplink issues. For example, handover failure may be due to uplink failure (e.g., uplink communication at the target cell is poor but downlink communication at the target cell is sufficient).
  • the source cell may send a sounding reference signal (SRS) request message (e.g., SCell SRS config message) to the UE requesting the UE to send SRS to the target cell in order for the target cell to determine an uplink channel condition.
  • SRS sounding reference signal
  • SCell SRS config message e.g., SCell SRS config message
  • the source cell receives one or more CQI reports related to both the source cell and the target cell (dual CQI) allowing the source cell to determine the downlink channel conditions at the UE for both the source cell and the target cell.
  • the target cell's knowledge of the uplink channel condition, and the source cell's knowledge of the downlink channel conditions may be exchanged between the source cell and the target cell via the X2. This allows the source cell and/or the target cell to make an informed decision regarding handover of the UE from the source cell to the target cell.
  • the source cell and/or target cell may trigger the handover based on the dual CQI (downlink channel condition) and the SRS (uplink channel condition) prompting the source cell and the target cell to negotiate the handover.
  • the source cell and/or the target cell may send a handover command to the UE.
  • the UE may perform a RACH procedure with the target cell to establish a connection with the target cell. This approach may be advantageous when there may be a high chance of the source cell link or the target cell link failing during handover, e.g., because the SNR of either link is too low.
  • sending the handover command from both the source cell and the target cell may be desired to achieve transmit diversity, which increases the chance of the UE receiving handover information when the source cell link or the target cell link is prone to failure.
  • the source cell may be considered as a secondary serving cell, or removed from a set of serving cells, while the target cell may be considered as the new primary serving cell.
  • FIG. 12 is a diagram 1200 illustrating yet another UE mobility procedure for use with a carrier aggregation scheme.
  • the UE mobility procedure of FIG. 12 allows handover to be more independent of the source cell (e.g., primary serving cell).
  • the target cell e.g., secondary serving cell
  • the UE may communicate with the source cell via a first radio and communicate with the target cell via a second radio.
  • the first radio and the second radio may operate on a same frequency.
  • a UE mobility procedure is further enhanced by allowing the target cell to receive CQI reports related to both the source cell and the target cell (dual CQI). Hence, both the source cell and the target cell may receive the dual CQI.
  • the target cell may send an aperiodic CQI request to the UE requesting the UE to send to the target cell CQI reports related to both the source cell and the target cell (dual CQI).
  • aperiodic CQI request to the UE requesting the UE to send to the target cell CQI reports related to both the source cell and the target cell (dual CQI).
  • dual CQI This allows the target cell to determine a downlink channel condition for both the source cell link and the target cell link. All periodic CQIs may be sent to the source cell (primary cell (PCell)).
  • PCell primary cell
  • the source cell and the target cell do not need to utilize the X2 backhaul to exchange information regarding the dual CQI.
  • the target cell may make an informed decision regarding handover of the UE from the source cell to the target cell.
  • the dual CQI is not lost because the target cell may independently receive the dual CQI from the UE after sending the aperiodic CQI request to the UE.
  • the source cell and/or target cell may trigger the handover based on the dual CQI (downlink channel condition) prompting the source cell and the target cell to negotiate the handover.
  • the source cell and/or the target cell may send a handover command to the UE.
  • the UE may perform a RACH procedure with the target cell to establish a connection with the target cell.
  • This approach may be advantageous when there may be a high chance of the source cell link or the target cell link failing during handover, e.g., because the SNR of either link is too low.
  • sending the handover command from both the source cell and the target cell may be desired to achieve transmit diversity, which increases the chance of the UE receiving handover information when the source cell link or the target cell link is prone to failure.
  • the source cell When the handover to the target cell is complete, the source cell may be considered as a secondary serving cell, or removed from a set of serving cells, while the target cell may be considered as the new primary serving cell.
  • FIG. 13 is a flow chart 1300 of a method of wireless communication.
  • the method may be performed by a UE facilitating a handover from a source cell (e.g., primary serving cell) to a target cell (e.g., secondary serving cell).
  • the UE may communicate with the source cell via a first radio.
  • Channel strength of the source cell may be decreasing while channel strength of the target cell may be increasing.
  • the UE may detect a presence of the target cell. Thereafter, at step 1306, the UE may send a message to the source cell to indicate the detected presence of the target cell. At step 1307, the UE may receive a command from the source cell (primary serving cell) to add the target cell as a secondary serving cell.
  • the UE may receive a message from the source cell requesting the UE to report channel quality information (CQI) related to the source cell and/or the target cell.
  • CQI channel quality information
  • the UE may activate a second radio to communicate with the target cell.
  • the UE communicates with the target cell and/or the source cell via the second radio to facilitate the handover to the target cell.
  • the first radio and the second radio may operate on a same frequency.
  • the UE may communicate with the source cell and the target cell via a single radio to facilitate the handover to the target cell.
  • the UE communication with the source cell may be time-division multiplexed with the UE communication with the target cell.
  • a downlink control channel of the source cell may not be used to schedule a target cell downlink transmission.
  • an uplink control channel to the source cell may not be used to provide an acknowledgment of the target cell downlink transmission.
  • the uplink control channel to the source cell may not be used to provide channel side information for the target cell downlink transmission.
  • Channel side information may include CQI, rank indicator (RI), precoding matrix indicator (PMI).
  • a scheduler may use CSI to decide a modulation and coding scheme (MCS), rank, and power of the transmission.
  • the UE may measure the CQI related to the target cell via the second radio. Alternatively, if only a single radio is used, then the UE measures the CQI related to the target cell via the single radio.
  • the UE may report, to the source cell, the CQI related to the source cell and the target cell. The source cell may use the reported CQI to make a handover decision. When the source cell decides to handover the UE to the target cell, the source cell negotiates the handover with the target cell. Thereafter, at step 1318, the UE may receive a handover command from at least one of the source cell or the target cell.
  • the method may proceed to either step 1402 or step 1450 of FIG. 14.
  • FIG. 14 illustrates flow charts 1400 and 1450 of methods of wireless communication.
  • the methods depicted in the flow charts 1400 and 1450 are alternative continuations to the path stemming from step 1316 of FIG. 13.
  • the UE may receive a message from the source cell requesting the UE to send a sounding reference signal (SRS) to the target cell.
  • the UE may send the SRS to the target cell.
  • the target cell may use the SRS to make a handover decision.
  • the UE may receive a handover command from at least one of the source cell or the target cell based on at least one of the SRS sent to the target cell or the CQI related to the source cell and the target cell reported to the source cell.
  • the UE may receive a message from the target cell requesting the UE to report to the target cell the CQI related to the source cell and the target cell.
  • the UE reports, to the target cell, the CQI related to the source cell and the target cell.
  • the target cell may use the reported CQI to make a handover decision.
  • the UE may receive a handover command from at least one of the source cell or the target cell based on at least one of the CQI related to the source cell and the target cell reported to the source cell or the CQI related to the source cell and the target cell reported to the target cell.
  • the UE may receive a message from the source cell requesting the UE to send a sounding reference signal (SRS) to the target cell.
  • SRS sounding reference signal
  • the UE sends the SRS to the target cell.
  • the target cell may further use the SRS to make the handover decision.
  • the UE may receive a handover command from at least one of the source cell or the target cell based on at least one of the SRS sent to the target cell, the CQI related to the source cell and the target cell reported to the source cell, or the CQI related to the source cell and the target cell reported to the target cell.
  • FIG. 15 is a flow chart 1500 of a method of wireless communication.
  • the method may be performed by a source cell (e.g., primary serving cell) and/or a target cell (e.g., secondary serving cell) communicating with a UE.
  • the source cell may communicate with the UE via a first radio.
  • the target cell may communicate with the UE via a second radio.
  • the first radio and the second radio may operate on a same frequency.
  • channel strength of the source cell may be decreasing while channel strength of the target cell may be increasing.
  • the source cell may receive a message from the UE indicating a detected presence of the target cell.
  • the source cell sends a message to the UE commanding the UE to add the target cell as a secondary serving cell.
  • the source cell may send a message to the UE requesting the UE to report channel quality information (CQI) related to the source cell and the target cell.
  • CQI channel quality information
  • the source cell may use the reported CQI to make a handover decision.
  • the source cell and the target cell may communicate with the UE via a single radio. In such a case, the communication with the UE at the source cell is time-division multiplexed with the communication with the UE at the target cell.
  • a downlink control channel of the source cell may not be used to schedule a target cell downlink transmission.
  • an uplink control channel to the source cell may not be used to provide an acknowledgment of the target cell downlink transmission.
  • the uplink control channel to the source cell may not be used to provide channel side information for the target cell downlink transmission.
  • Channel side information may include CQI, rank indicator (RI), and precoding matrix indicator (PMI).
  • a scheduler may use CSI to decide a modulation and coding scheme (MCS), rank, and power of the transmission.
  • the source cell receives a report from the UE reporting the CQI related to the source cell and the target cell.
  • the source cell may determine a handover to the target cell based on the received report.
  • the source cell and the target cell may negotiate the handover.
  • the target cell may send a handover command to the UE.
  • the source cell may also send the handover command to the UE separately from the handover command sent from the target cell.
  • the method may proceed to either step 1602 or step 1650 of FIG. 16.
  • FIG. 16 illustrates flow charts 1600 and 1650 of methods of wireless communication.
  • the methods depicted in the flow charts 1600 and 1650 are alternative continuations to the path stemming from step 1510 of FIG. 15.
  • the source cell may send a message to the UE requesting the UE to send a sounding reference signal (SRS) to the target cell.
  • the target cell receives the SRS from the UE.
  • handover to the target cell is determined based on at least one of the report received at the source cell reporting the CQI related to the source cell and the target cell or the SRS received at the target cell.
  • a handover command is sent to the UE from at least one of the source cell or the target cell based on at least one of the report received at the source cell reporting the CQI related to the source cell and the target cell or the SRS received at the target cell.
  • the target cell sends a message to the UE requesting the UE to report to the target cell the CQI related to the source cell and the target cell.
  • the target cell receives the report from the UE reporting the CQI related to the source cell and the target cell.
  • handover to the target cell is determined based on at least one of the report received at the source cell reporting the CQI related to the source cell and the target cell or the report received at the target cell reporting the CQI related to the source cell and the target cell.
  • a handover command is sent to the UE from at least one of the source cell or the target cell based on at least one of the report received at the source cell reporting the CQI related to the source cell and the target cell or the report received at the target cell reporting the CQI related to the source cell and the target cell.
  • the source cell may send a message to the UE requesting the UE to send a sounding reference signal (SRS) to the target cell.
  • the target cell receives the SRS from the UE.
  • the target cell may determine the handover further based on the received SRS.
  • a handover command from at least one of the source cell or the target cell may be sent to the UE based on at least one of the report received at the source cell reporting the CQI related to the source cell and the target cell, the report received at the target cell reporting the CQI related to the source cell and the target cell, or the SRS received at the target cell.
  • FIG. 17 is a flow chart 1700 of a method of wireless communication.
  • the method may be performed by a UE for receiving data from a primary serving cell and a secondary serving cell.
  • the UE sends a capability message to at least one of the primary cell or the secondary cell.
  • the capability message may indicate a capability of communicating via a first component carrier corresponding to the primary serving cell and a second component carrier corresponding to the secondary serving cell, wherein the first component carrier and the second component carrier operate on the same frequency.
  • the UE communicates with the primary serving cell via the first component carrier.
  • the UE communicates with the secondary serving cell via the second component carrier.
  • the UE receives data samples from both the primary serving cell and the secondary serving cell.
  • the data samples are received simultaneously from both the primary serving cell and the secondary serving cell when the data samples are simultaneously received via a baseband receiver capable of simultaneously receiving via both the first component carrier and the second component carrier.
  • the capability message may indicate whether the baseband receiver is capable of simultaneously receiving via both the first component carrier and the second component carrier.
  • the UE may receive the data samples from the primary serving cell and the secondary serving cell in a non-simultaneous manner when the data samples from the primary serving cell and the secondary serving cell are time- division multiplexed.
  • the UE may disable simultaneous transmission via the first component carrier and the second component carrier operating on the same frequency.
  • Communicating with the primary serving cell and the secondary serving cell may be implemented via a single radio or a plurality of radios.
  • FIG. 18 is a conceptual data flow diagram 1800 illustrating the data flow between different modules/means/components in an exemplary apparatus 1802.
  • the apparatus may be a UE.
  • the apparatus includes a receiving module 1804, a cell communication module 1806, a cell presence detection module 1808, a channel quality information (CQI) module 1810, a handover processing module 1812, a sounding reference signal (SRS) module 1814, and a transmission module 1814.
  • a base station 1850 may represent a source cell or a target cell.
  • the cell communication module 1806 may communicate with the source cell (e.g., primary serving cell) via a first radio.
  • Channel strength of the source cell may be decreasing while channel strength of the target cell (e.g., secondary serving cell) may be increasing. Accordingly, as the channel strength of the target cell increases, the cell presence detection module 1808 may detect a presence of the target cell. Thereafter, the cell presence detection module 1808 may send a message to the source cell via the transmission module 1814 to indicate the detected presence of the target cell.
  • the cell communication module 1806 may receive a command from the source cell (primary serving cell) to add the target cell as a secondary serving cell.
  • the CQI module 1810 may receive a message from the source cell requesting the apparatus 1802 to report channel quality information (CQI) related to the source cell and/or the target cell.
  • the cell communication module 1806 may activate a second radio to communicate with the target cell.
  • the cell communication module 1806 communicates with the target cell and/or the source cell via the second radio to facilitate a handover to the target cell.
  • the first radio and the second radio may operate on a same frequency.
  • the apparatus 1802 may communicate with the source cell and the target cell via a single radio to facilitate the handover to the target cell.
  • the communication with the source cell may be time-division multiplexed with the communication with the target cell.
  • a downlink control channel of the source cell may not be used to schedule a target cell downlink transmission.
  • an uplink control channel to the source cell may not be used to provide an acknowledgment of the target cell downlink transmission.
  • the uplink control channel to the source cell may not be used to provide channel side information for the target cell downlink transmission.
  • Channel side information may include CQI, rank indicator (RI), precoding matrix indicator (PMI).
  • a scheduler may use CSI to decide a modulation and coding scheme (MCS), rank, and power of the transmission.
  • the CQI module 1810 may measure the CQI related to the target cell via the second radio.
  • the CQI module 1810 may report, to the source cell, the CQI related to the source cell and the target cell.
  • the source cell may use the reported CQI to make a handover decision.
  • the source cell decides to handover the UE to the target cell, the source cell negotiates the handover with the target cell.
  • the handover processing module 1812 may receive a handover command from at least one of the source cell or the target cell.
  • the SRS module 1814 may receive a message from the source cell requesting the apparatus 1802 to send a sounding reference signal (SRS) to the target cell.
  • the SRS module 1814 may send the SRS to the target cell.
  • the target cell may use the SRS to make a handover decision.
  • the handover processing module 1812 may receive a handover command from at least one of the source cell or the target cell based on at least one of the SRS sent to the target cell or the CQI related to the source cell and the target cell reported to the source cell.
  • the CQI module 1810 may receive a message from the target cell requesting the UE to report to the target cell the CQI related to the source cell and the target cell.
  • the CQI module 1810 reports, to the target cell, the CQI related to the source cell and the target cell.
  • the target cell may use the reported CQI to make a handover decision.
  • the handover processing module 1812 may receive a handover command from at least one of the source cell or the target cell based on at least one of the CQI related to the source cell and the target cell reported to the source cell or the CQI related to the source cell and the target cell reported to the target cell.
  • the SRS module 1814 may receive a message from the source cell requesting the apparatus 1802 to send a sounding reference signal (SRS) to the target cell.
  • the SRS module 1814 sends the SRS to the target cell.
  • the target cell may further use the SRS to make the handover decision.
  • the handover processing module 1812 may receive a handover command from at least one of the source cell or the target cell based on at least one of the SRS sent to the target cell, the CQI related to the source cell and the target cell reported to the source cell, or the CQI related to the source cell and the target cell reported to the target cell.
  • the cell communication module 1806 sends a capability message to at least one of a primary cell or a secondary cell.
  • the capability message may indicate a capability of communicating via a first component carrier corresponding to the primary cell and a second component carrier corresponding to the secondary cell, wherein the first component carrier and the second component carrier operate on the same frequency.
  • the cell communication module 1806 communicates with the primary cell via the first component carrier and with the secondary cell via the second component carrier.
  • the receiving module 1804 receives data samples from both the primary cell and the secondary cell.
  • the data samples are received simultaneously from both the primary cell and the secondary cell when the data samples are simultaneously received via a baseband receiver capable of simultaneously receiving via both the first component carrier and the second component carrier.
  • the capability message may indicate whether the baseband receiver is capable of simultaneously receiving via both the first component carrier and the second component carrier.
  • the receiving module 1806 may receive the data samples from the primary cell and the secondary cell in a non-simultaneous manner when the data samples from the primary cell and the secondary cell are time-division multiplexed.
  • the transmission module 1816 may disable simultaneous transmission via the first component carrier and the second component carrier operating on the same frequency. Communicating with the primary cell and the secondary cell may be implemented via a single radio or a plurality of radios.
  • FIG. 19 is a conceptual data flow diagram 1900 illustrating the data flow between different modules/means/components in an exemplary apparatus 1902.
  • the apparatus may be a source eNB (e.g., primary serving cell) and/or a target eNB (e.g., secondary serving cell).
  • the apparatus includes a receiving module 1904, a UE communication module 1906, a cell presence processing module 1908, a channel quality information (CQI) module, a handover processing module 1912, a sounding reference signal (SRS) module 1914, and a transmission module 1916.
  • CQI channel quality information
  • SRS sounding reference signal
  • the UE communication module 1906 of the source eNB may communicate with a UE 1950 via a first radio.
  • the UE communication module 1906 of the target eNB may communicate with the UE via a second radio.
  • the first radio and the second radio may operate on a same frequency.
  • channel strength of the source eNB may be decreasing while channel strength of the target eNB may be increasing.
  • the cell presence processing module 1908 of the source eNB may receive a message from the UE 1950 indicating a detected presence of the target eNB.
  • the UE communication module 1906 of the source eNB may send a message to the UE 1950 commanding the UE 1950 to add the target eNB as a secondary serving cell.
  • the CQI module 1910 of the source eNB may send a message to the UE 1950 requesting the UE 1950 to report channel quality information (CQI) related to the source eNB and the target eNB.
  • CQI channel quality information
  • the handover processing module 1912 of the source eNB may use the reported CQI to make a handover decision.
  • the UE communication module 1906 of the source eNB and the UE communication module 1906 of the target eNB may communicate with the UE 1950 via a single radio.
  • the communication with the UE 1950 at the source eNB is time-division multiplexed with the communication with the UE at the target eNB.
  • a downlink control channel of the source eNB may not be used to schedule a target eNB downlink transmission.
  • an uplink control channel to the source eNB may not be used to provide an acknowledgment of the target eNB downlink transmission.
  • the uplink control channel to the source eNB may not be used to provide channel side information for the target eNB downlink transmission.
  • Channel side information may include CQI, rank indicator (RI), precoding matrix indicator (PMI).
  • a scheduler may use CSI to decide a modulation and coding scheme (MCS), rank, and power of the transmission.
  • the CQI module 1910 of the source eNB receives a report from the UE 1950 reporting the CQI related to the source eNB and the target eNB.
  • the handover processing module 1912 of the source eNB may determine a handover to the target eNB based on the received report. When the handover is determined, the source eNB and the target eNB may negotiate the handover.
  • the handover processing module 1912 of the target eNB may send a handover command to the UE 1950.
  • the handover processing module 1912 of the source eNB may also send the handover command to the UE 1950 separately from the handover command sent from the target eNB.
  • the SRS module 1914 of the source eNB may send a message to the UE 1950 requesting the UE 1950 to send a sounding reference signal (SRS) to the target eNB.
  • the SRS module 1914 of the target eNB receives the SRS from the UE 1950.
  • Handover to the target eNB is determined by the handover processing module 1912 based on at least one of the report received at the source eNB reporting the CQI related to the source eNB and the target eNB or the SRS received at the target eNB.
  • the handover processing module 1912 sends a handover command to the UE from at least one of the source eNB or the target eNB based on at least one of the report received at the source eNB reporting the CQI related to the source eNB and the target eNB or the SRS received at the target eNB. [00137] In another alternative, after the CQI module 1910 of the source eNB receives the CQI module 1910 of the source eNB.
  • the CQI module 1910 of the target eNB sends a message to the UE 1950 requesting the UE 1950 to report to the target eNB the CQI related to the source eNB and the target eNB.
  • the CQI module 1910 of the target eNB receives the report from the UE 1950 reporting the CQI related to the source eNB and the target eNB.
  • Handover to the target eNB is determined by the handover processing module 1912 based on at least one of the report received at the source eNB reporting the CQI related to the source eNB and the target eNB or the report received at the target eNB reporting the CQI related to the source eNB and the target eNB.
  • the handover processing module 1912 sends a handover command to the UE 1950 from at least one of the source eNB or the target eNB based on at least one of the report received at the source eNB reporting the CQI related to the source eNB and the target eNB or the report received at the target eNB reporting the CQI related to the source eNB and the target eNB.
  • the SRS module 1914 of the source eNB may alternatively send a message to the UE 1950 requesting the UE 1950 to send a sounding reference signal (SRS) to the target eNB.
  • the SRS module 1914 of the target eNB receives the SRS from the UE 1950.
  • the handover processing module 1912 of the target eNB may determine the handover further based on the received SRS.
  • the handover processing module 1912 may send a handover command to the UE 1950 from at least one of the source eNB or the target eNB based on at least one of the report received at the source eNB reporting the CQI related to the source eNB and the target eNB, the report received at the target eNB reporting the CQI related to the source eNB and the target eNB, or the SRS received at the target eNB.
  • the apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow charts of FIGs. 13-17. As such, each step in the aforementioned flow charts of FIGs. 13-17 may be performed by a module and the apparatus may include one or more of those modules.
  • the modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.
  • FIG. 20 is a diagram 2000 illustrating an example of a hardware implementation for an apparatus 1802' employing a processing system 2014.
  • the processing system 2014 may be implemented with a bus architecture, represented generally by the bus 2024.
  • the bus 2024 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 2014 and the overall design constraints.
  • the bus 2024 links together various circuits including one or more processors and/or hardware modules, represented by the processor 2004, the modules 1804, 1806, 1808, 1810, 1812, 1814, 1816, and the computer-readable medium 2006.
  • the bus 2024 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.
  • the processing system 2014 may be coupled to a transceiver 2010.
  • the transceiver 2010 is coupled to one or more antennas 2020.
  • the transceiver 2010 provides a means for communicating with various other apparatus over a transmission medium.
  • the processing system 2014 includes a processor 2004 coupled to a computer-readable medium 2006.
  • the processor 2004 is responsible for general processing, including the execution of software stored on the computer- readable medium 2006.
  • the software when executed by the processor 2004, causes the processing system 2014 to perform the various functions described supra for any particular apparatus.
  • the computer-readable medium 2006 may also be used for storing data that is manipulated by the processor 2004 when executing software.
  • the processing system further includes at least one of the modules 1804, 1806, 1808, 1810, 1812, 1814, and 1816.
  • the modules may be software modules running in the processor 2004, resident/stored in the computer readable medium 2006, one or more hardware modules coupled to the processor 2004, or some combination thereof.
  • the processing system 2014 may be a component of the UE 650 and may include the memory 660 and/or at least one of the TX processor 668, the RX processor 656, and the controller/processor 659.
  • the apparatus 1802/1802' for wireless communication includes means for communicating with a source cell via a first radio, means for communicating with at least one of the source cell or a target cell via a second radio to facilitate a handover to the target cell, the first radio and the second radio operating on a same frequency, means for detecting a presence of the target cell, means for sending a first message to the source cell indicating the detected presence of the target cell, means for receiving a command from the source cell to add the target cell as a secondary serving cell, means for receiving a second message from the source cell, the second message including a request to report channel quality information (CQI) related to the source cell and the target cell, means for activating the second radio to communicate with the target cell, means for measuring the CQI related to the target cell via the second radio, means for reporting, to the source cell, the CQI related to the source cell and the target cell, means for receiving a handover command from at least one of the source cell or the target cell, means for measuring the CQI
  • CQI channel quality
  • the aforementioned means may be one or more of the aforementioned modules of the apparatus 1802 and/or the processing system 2014 of the apparatus 1802' configured to perform the functions recited by the aforementioned means.
  • the processing system 2014 may include the TX Processor 668, the RX Processor 656, and the controller/processor 659.
  • the aforementioned means may be the TX Processor 668, the RX Processor 656, and the controller/processor 659 configured to perform the functions recited by the aforementioned means.
  • FIG. 21 is a diagram 2100 illustrating an example of a hardware implementation for an apparatus 1902' employing a processing system 2114.
  • the processing system 21 14 may be implemented with a bus architecture, represented generally by the bus 2124.
  • the bus 2124 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 21 14 and the overall design constraints.
  • the bus 2124 links together various circuits including one or more processors and/or hardware modules, represented by the processor 2104, the modules 1904, 1906, 1908, 1910, 1912, 1914, 1916, and the computer-readable medium 2106.
  • the bus 2124 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.
  • the processing system 21 14 may be coupled to a transceiver 21 10.
  • the transceiver 21 10 is coupled to one or more antennas 2120.
  • the transceiver 2110 provides a means for communicating with various other apparatus over a transmission medium.
  • the processing system 2114 includes a processor 2104 coupled to a computer-readable medium 2106.
  • the processor 2104 is responsible for general processing, including the execution of software stored on the computer- readable medium 2106.
  • the software when executed by the processor 2104, causes the processing system 2114 to perform the various functions described supra for any particular apparatus.
  • the computer-readable medium 2106 may also be used for storing data that is manipulated by the processor 2104 when executing software.
  • the processing system further includes at least one of the modules 1904, 1906, 1908, 1910, 1912, 1914, and 1916.
  • the modules may be software modules running in the processor 2104, resident/stored in the computer readable medium 2106, one or more hardware modules coupled to the processor 2104, or some combination thereof.
  • the processing system 21 14 may be a component of the eNB 610 and may include the memory 676 and/or at least one of the TX processor 616, the RX processor 670, and the controller/processor 675.
  • the apparatus 1902/1902' for wireless communication includes means for communicating with a user equipment (UE) via a first radio at a source cell, means for communicating with the UE via a second radio at a target cell, means for receiving, at the source cell, a first message from the UE indicating a detected presence of the target cell, means for sending a second message from the source cell to the UE, the second message including a command to add the target cell as a secondary serving cell, means for sending from the source cell to the UE a request to report channel quality information (CQI) related to the source cell and the target cell, means for receiving, at the source cell, a report from the UE reporting the CQI related to the source cell and the target cell, means for determining, at the source cell, a handover to the target cell based on the received report, means for negotiating the handover between the source cell and the target cell, means for sending, to the UE, a handover command from the target cell upon negotiating the handover, means for
  • CQI channel quality
  • the aforementioned means may be one or more of the aforementioned modules of the apparatus 1902 and/or the processing system 2114 of the apparatus 1902' configured to perform the functions recited by the aforementioned means.
  • the processing system 21 14 may include the TX Processor 616, the RX Processor 670, and the controller/processor 675.
  • the aforementioned means may be the TX Processor 616, the RX Processor 670, and the controller/processor 675 configured to perform the functions recited by the aforementioned means.
  • Combinations such as "at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B, C, or any combination thereof include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C.
  • combinations such as “at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B, C, or any combination thereof may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C.

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JP2015516777A (ja) 2015-06-11
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