WO2014165711A1 - Mécanismes améliorés de coordination d'interférences pour un faible déploiement de cellules - Google Patents

Mécanismes améliorés de coordination d'interférences pour un faible déploiement de cellules Download PDF

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Publication number
WO2014165711A1
WO2014165711A1 PCT/US2014/032889 US2014032889W WO2014165711A1 WO 2014165711 A1 WO2014165711 A1 WO 2014165711A1 US 2014032889 W US2014032889 W US 2014032889W WO 2014165711 A1 WO2014165711 A1 WO 2014165711A1
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Prior art keywords
csi
wtru
cell
resources
interference
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PCT/US2014/032889
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English (en)
Inventor
J. Patrick Tooher
Paul Marinier
Diana Pani
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Interdigital Patent Holdings, Inc.
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Application filed by Interdigital Patent Holdings, Inc. filed Critical Interdigital Patent Holdings, Inc.
Publication of WO2014165711A1 publication Critical patent/WO2014165711A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports

Definitions

  • a wireless transmit/receive unit may make measurements for either physical layer feedback reporting of Channel State Information (CSI) or higher-layer reporting of Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ).
  • CSI Channel State Information
  • RSRP Reference Signal Received Power
  • RSRQ Reference Signal Received Quality
  • subset subframes were introduced that allowed a network to receive feedback reports as well as higher layer measurements for subsets of subframes.
  • certain types of patterns were introduced in R10: a subset of subframes to be assumed for serving cell RSRP measurement, a subset of subframes to be assumed for a neighbor cell's RSRP measurement, and two subsets of patterns to be used for CSI measurements.
  • a WTRU may filter out measurements on cell- specific reference signals (CRS) to obtain interference values that may be used in CQI determination.
  • CRS cell-specific reference signals
  • interference measurements were enhanced.
  • Interference measurement resources (CSI-IM) were specified as resources on which a WTRU may measure interference.
  • CSI-IM Interference measurement resources
  • a serving cell may use ZP CSI-RS on the same REs that it configures a WTRU with a CSI-IM. This ensures that any signal measured on such an RE is solely caused by interference and noise.
  • Each CSI process is configured with a single CSI-IM and a single CSI- RS. There is no further specification on how a WTRU should measure interference on such a CSI-IM.
  • Interference may be coordinated in a wireless network with small cell deployment.
  • a cell may perform state transitions during certain defined times, which may be fixed time instances and/or patterns of state transitions.
  • a wireless transmit/receive unit (WTRU) may be signaled regarding the defined times.
  • An interference measurement result may be reported.
  • a WTRU may be configured with patterns of different interference periods for both CSI feedback and RSRP/RSRQ measurements. These patterns may be configured with CSI-IMs and/or CSI Processes or may be used in conjunction with CSI-IM and/or CSI Processes.
  • a WTRU may be configured with multiple sets of CSI-IMs and/or CSI Processes.
  • the WTRU may receive a dynamic indication to determine which CSI-IM and/or CSI process set is relevant at any given moment. Interference measurements may be reported at RRC based on measuring energy or noise over a set of resources within a subband.
  • a subset of subframes may be configured for CSI measurement and reporting.
  • a time division duplexing (TDD) WTRU may be configured with two types of downlink subframes. Some subframes, which may be referred to as fixed downlink subframes, may always be considered downlink, while other subframes, which may be referred to as flexible downlink subframes, may sometimes be used for uplink transmissions and may sometimes be used for downlink transmissions.
  • TDD time division duplexing
  • a WTRU may be configured with channel state information (CSI) resources to perform measurements.
  • a WTRU may feedback CSI for fixed downlink, flexible downlink, or off subframes.
  • a WTRU may be configured to include measurements for a cell state assumption (e.g., a fixed downlink subframe state, a flexible downlink subframe state, and/or an off subframe state) in a periodic or aperiodic CSI feedback report.
  • a WTRU may be configured with different CSI Processes for measurements that may or may not include flexible downlink subframes.
  • a WTRU may be configured, e.g., dynamically, to include measurements taken in flexible downlink subframes in a CSI feedback report.
  • Feedback reporting may enable dynamic power backoff.
  • a WTRU may be indicated whether a subframe uses power backoff or not. This indication may be provided dynamically or semi-statically.
  • FIG. 1A is a system diagram of an example communications system in which one or more disclosed embodiments may be implemented
  • FIG. IB is a system diagram of an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A;
  • WTRU wireless transmit/receive unit
  • FIG. 1 C is a system diagram of an example radio access network and an example core network that may be used within the communications system illustrated in FIG. 1A;
  • FIG. ID is a system diagram of an another example radio access network and another example core network that may be used within the communications system illustrated in FIG.
  • FIG. IE is a system diagram of an another example radio access network and another example core network that may be used within the communications system illustrated in FIG. 1A;
  • FIG. 2 is a diagram illustrating examples of allowed patterns of state transitions in a cell in a wireless network.
  • FIG. 1A is a diagram of an example communications system 100 in which one or more disclosed embodiments may be implemented.
  • the communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users.
  • the communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth.
  • the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single- carrier FDMA (SC-FDMA), and the like.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal FDMA
  • SC-FDMA single- carrier FDMA
  • the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, and/or 102d (which generally or collectively may be referred to as WTRU 102), a radio access network (RAN) 103/104/105, a core network 106/107/109, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 1 12, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements.
  • Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment.
  • the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and/or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, consumer electronics, and the like.
  • UE user equipment
  • PDA personal digital assistant
  • smartphone a laptop
  • netbook a personal computer
  • a wireless sensor consumer electronics, and the like.
  • the communications systems 100 may also include a base station 1 14a and a base station 1 14b.
  • Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the core network 106/107/109, the Internet 1 10, and/or the networks 112.
  • the base stations 1 14a, 1 14b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 1 14a, 1 14b are each depicted as a single element, it will be appreciated that the base stations 1 14a, 1 14b may include any number of interconnected base stations and/or network elements.
  • the base station 1 14a may be part of the RAN 103/104/105, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc.
  • BSC base station controller
  • RNC radio network controller
  • the base station 1 14a and/or the base station 1 14b may be configured to transmit and/or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown).
  • the cell may further be divided into cell sectors.
  • the cell associated with the base station 1 14a may be divided into three sectors.
  • the base station 114a may include three transceivers, e.g., one for each sector of the cell.
  • the base station 114a may employ multiple-input multiple output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell.
  • MIMO multiple-input multiple output
  • the base stations 1 14a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 1 15/116/1 17, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.).
  • the air interface 1 15/116/1 17 may be established using any suitable radio access technology (RAT).
  • RAT radio access technology
  • the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like.
  • the base station 1 14a in the RAN 103/104/105 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 1 15/116/1 17 using wideband CDMA (WCDMA).
  • UMTS Universal Mobile Telecommunications System
  • UTRA Universal Mobile Telecommunications System Terrestrial Radio Access
  • WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+).
  • HSPA may include High-Speed Downlink Packet Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).
  • HSPA High-Speed Packet Access
  • HSDPA High-Speed Downlink Packet Access
  • HSUPA High-Speed Uplink Packet Access
  • the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 115/116/1 17 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE- A).
  • E-UTRA Evolved UMTS Terrestrial Radio Access
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • the base station 1 14a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.
  • IEEE 802.16 e.g., Worldwide Interoperability for Microwave Access (WiMAX)
  • CDMA2000, CDMA2000 IX, CDMA2000 EV-DO Code Division Multiple Access 2000
  • IS-95 Interim Standard 95
  • IS-856 Interim Standard 856
  • GSM Global System for Mobile communications
  • GSM Global System for Mobile communications
  • EDGE Enhanced Data rates for GSM Evolution
  • GERAN GSM EDGERAN
  • the base station 1 14b in FIG. 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, and the like.
  • the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.1 1 to establish a wireless local area network (WLAN).
  • the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN).
  • WLAN wireless local area network
  • WPAN wireless personal area network
  • the base station 114b and the WTRUs 102c, 102d may utilize a cellular- based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell.
  • a cellular- based RAT e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.
  • the base station 114b may have a direct connection to the Internet 1 10.
  • the base station 114b may not be required to access the Internet 1 10 via the core network 106/107/109.
  • the RAN 103/104/105 may be in communication with the core network 106/107/109, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d.
  • the core network 106/107/109 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication.
  • VoIP voice over internet protocol
  • the RAN 103/104/105 and/or the core network 106/107/109 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 103/104/105 or a different RAT.
  • the core network in addition to being connected to the RAN 103/104/105, which may be utilizing an E-UTRA radio technology, the core network
  • 106/107/109 may also be in communication with another RAN (not shown) employing a GSM radio technology.
  • the core network 106/107/109 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 1 10, and/or other networks 112.
  • the PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS).
  • POTS plain old telephone service
  • the Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and the internet protocol (IP) in the TCP/IP internet protocol suite.
  • the networks 1 12 may include wired or wireless communications networks owned and/or operated by other service providers.
  • the networks 112 may include another core network connected to one or more RANs, which may employ the same RAT as the RAN 103/104/105 or a different RAT.
  • Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities, e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.
  • the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 1 14b, which may employ an IEEE 802 radio technology.
  • FIG. IB is a system diagram of an example WTRU 102.
  • the WTRU 102 may include a processor 1 18, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and other peripherals 138.
  • GPS global positioning system
  • the base stations 114a and 114b, and/or the nodes that base stations 114a and 114b may represent, such as but not limited to transceiver station (BTS), a Node-B, a site controller, an access point (AP), a home node-B, an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a home evolved node-B gateway, and proxy nodes, among others, may include some or all of the elements depicted in FIG. IB and described herein.
  • BTS transceiver station
  • Node-B a Node-B
  • AP access point
  • eNodeB evolved home node-B
  • HeNB home evolved node-B gateway
  • proxy nodes among others, may include some or all of the elements depicted in FIG. IB and described herein.
  • the processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller,
  • DSP digital signal processor
  • the processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment.
  • the processor 1 18 may be coupled to the transceiver 120, which may be coupled to the
  • FIG. IB depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.
  • a processor such as the processor 118, may include integrated memory (e.g., WTRU 102 may include a chipset that includes a processor and associated memory).
  • Memory may refer to memory that is integrated with a processor (e.g., processor 1 18) or memory that is otherwise associated with a device (e.g., WTRU 102).
  • the memory may be non-transitory.
  • the memory may include (e.g., store) instructions that may be executed by the processor (e.g., software and/or firmware instructions).
  • the memory may include instructions that when executed may cause the processor to implement one or more of the implementations described herein.
  • the transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 1 14a) over the air interface 1 15/116/1 17.
  • a base station e.g., the base station 1 14a
  • the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals.
  • the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example.
  • the transmit/receive element 122 may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.
  • the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 115/1 16/1 17.
  • the transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, for example.
  • the processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit).
  • the processor 1 18 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128.
  • the processor 1 18 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130, the removable memory 132, and/or memory integrated with the processor 118.
  • the non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device.
  • the removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like.
  • SIM subscriber identity module
  • SD secure digital
  • the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).
  • the processor 1 18 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102.
  • the power source 134 may be any suitable device for powering the WTRU 102.
  • the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.
  • the processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102.
  • location information e.g., longitude and latitude
  • the WTRU 102 may receive location information over the air interface 1 15/116/1 17 from a base station (e.g., base stations 1 14a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.
  • the processor 1 18 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity.
  • the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like.
  • the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player
  • FIG. 1C is a system diagram of the RAN 103 and the core network 106 according to an embodiment.
  • the RAN 103 may employ a UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 1 15.
  • the RAN 103 may also be in communication with the core network 106.
  • the RAN 103 may include Node-Bs 140a, 140b, 140c, which may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 115.
  • the Node-Bs 140a, 140b, 140c may each be associated with a particular cell (not shown) within the RAN 103.
  • the RAN 103 may also include RNCs 142a, 142b. It will be appreciated that the RAN 103 may include any number of Node-Bs and RNCs while remaining consistent with an embodiment.
  • the Node-Bs 140a, 140b may be in communication with the RNC 142a. Additionally, the Node-B 140c may be in communication with the RNC142b.
  • the Node-Bs 140a, 140b, 140c may communicate with the respective RNCs 142a, 142b via an Iub interface.
  • the RNCs 142a, 142b may be in communication with one another via an Iur interface.
  • Each of the RNCs 142a, 142b may be configured to control the respective Node-Bs 140a, 140b, 140c to which it is connected.
  • each of the RNCs 142a, 142b may be configured to carry out or support other functionality, such as outer loop power control, load control, admission control, packet scheduling, handover control, macrodiversity, security functions, data encryption, and the like.
  • the core network 106 shown in FIG. 1C may include a media gateway (MGW) 144, a mobile switching center (MSC) 146, a serving GPRS support node (SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. While each of the foregoing elements are depicted as part of the core network 106, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator.
  • MGW media gateway
  • MSC mobile switching center
  • SGSN serving GPRS support node
  • GGSN gateway GPRS support node
  • the RNC 142a in the RAN 103 may be connected to the MSC 146 in the core network 106 via an IuCS interface.
  • the MSC 146 may be connected to the MGW 144.
  • the MSC 146 and the MGW 144 may provide the WTRUs 102a, 102b, 102c with access to circuit- switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices.
  • the RNC 142a in the RAN 103 may also be connected to the SGSN 148 in the core network 106 via an IuPS interface.
  • the SGSN 148 may be connected to the GGSN 150.
  • the SGSN 148 and the GGSN 150 may provide the WTRUs 102a, 102b, 102c with access to packet- switched networks, such as the Internet 110, to facilitate communications between and the WTRUs 102a, 102b, 102c and IP-enabled devices.
  • packet- switched networks such as the Internet 110
  • the core network 106 may also be connected to the networks 112, which may include other wired or wireless networks that are owned and/or operated by other service providers.
  • FIG. ID is a system diagram of the RAN 104 and the core network 107 according to an embodiment.
  • the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 1 16.
  • the RAN 104 may also be in communication with the core network 107.
  • the RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment.
  • the eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one
  • the eNode-Bs 160a, 160b, 160c may implement MIMO technology.
  • the eNode-B 160a for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.
  • Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown in FIG. ID, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.
  • the core network 107 shown in FIG. ID may include a mobility management gateway (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway 166. While each of the foregoing elements are depicted as part of the core network 107, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator.
  • MME mobility management gateway
  • PDN packet data network
  • the MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an SI interface and may serve as a control node.
  • the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer
  • the MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.
  • the serving gateway 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via the SI interface.
  • the serving gateway 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c.
  • the serving gateway 164 may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.
  • the serving gateway 164 may also be connected to the PDN gateway 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.
  • the PDN gateway 166 may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.
  • the core network 107 may facilitate communications with other networks.
  • the core network 107 may provide the WTRUs 102a, 102b, 102c with access to circuit- switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices.
  • the core network 107 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the core network 107 and the PSTN 108.
  • IMS IP multimedia subsystem
  • the core network 107 may provide the WTRUs 102a, 102b, 102c with access to the networks 112, which may include other wired or wireless networks that are owned and/or operated by other service providers.
  • FIG. IE is a system diagram of the RAN 105 and the core network 109 according to an embodiment.
  • the RAN 105 may be an access service network (ASN) that employs IEEE 802.16 radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 117.
  • ASN access service network
  • the communication links between the different functional entities of the WTRUs 102a, 102b, 102c, the RAN 105, and the core network 109 may be defined as reference points.
  • the RAN 105 may include base stations 180a, 180b, 180c, and an ASN gateway 182, though it will be appreciated that the RAN 105 may include any number of base stations and ASN gateways while remaining consistent with an embodiment.
  • the base stations 180a, 180b, 180c may each be associated with a particular cell (not shown) in the RAN 105 and may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 1 17.
  • the base stations 180a, 180b, 180c may implement MIMO technology.
  • the base station 180a for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.
  • the base stations 180a, 180b, 180c may also provide mobility management functions, such as handoff triggering, tunnel establishment, radio resource management, traffic classification, quality of service (QoS) policy enforcement, and the like.
  • the ASN gateway 182 may serve as a traffic aggregation point and may be responsible for paging, caching of subscriber profiles, routing to the core network 109, and the like.
  • the air interface 1 17 between the WTRUs 102a, 102b, 102c and the RAN 105 may be defined as an Rl reference point that implements the IEEE 802.16 specification.
  • each of the WTRUs 102a, 102b, 102c may establish a logical interface (not shown) with the core network 109.
  • the logical interface between the WTRUs 102a, 102b, 102c and the core network 109 may be defined as an R2 reference point, which may be used for authentication,
  • the communication link between each of the base stations 180a, 180b, 180c may be defined as an R8 reference point that includes protocols for facilitating WTRU handovers and the transfer of data between base stations.
  • the communication link between the base stations 180a, 180b, 180c and the ASN gateway 182 may be defined as an R6 reference point.
  • the R6 reference point may include protocols for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.
  • the RAN 105 may be connected to the core network 109.
  • the communication link between the RAN 105 and the core network 109 may defined as an R3 reference point that includes protocols for facilitating data transfer and mobility management capabilities, for example.
  • the core network 109 may include a mobile IP home agent (MIP-HA) 184, an authentication, authorization, accounting (AAA) server 186, and a gateway 188. While each of the foregoing elements are depicted as part of the core network 109, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator.
  • MIP-HA mobile IP home agent
  • AAA authentication, authorization, accounting
  • the MIP-HA may be responsible for IP address management, and may enable the WTRUs 102a, 102b, 102c to roam between different ASNs and/or different core networks.
  • the MIP-HA 184 may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.
  • the AAA server 186 may be responsible for user authentication and for supporting user services.
  • the gateway 188 may facilitate interworking with other networks.
  • the gateway 188 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices.
  • the gateway 188 may provide the WTRUs 102a, 102b, 102c with access to the networks 1 12, which may include other wired or wireless networks that are owned and/or operated by other service providers.
  • the RAN 105 may be connected to other ASNs and the core network 109 may be connected to other core networks.
  • the communication link between the RAN 105 the other ASNs may be defined as an R4 reference point, which may include protocols for coordinating the mobility of the WTRUs 102a, 102b, 102c between the RAN 105 and the other ASNs.
  • the communication link between the core network 109 and the other core networks may be defined as an R5 reference, which may include protocols for facilitating interworking between home core networks and visited core networks.
  • Dense cell deployments may increase throughput gains by increasing cell splitting. However, such gains may be negated by an increase in overall inter-cell interference.
  • cell behavior may be dynamic; for example, a cell may switch from active to dormant state, may coordinate with other cells for the usage of resources, or it may switch time division duplexing (TDD) configurations dynamically.
  • TDD time division duplexing
  • the interference landscape may change rapidly.
  • a WTRU may filter interference measurements over multiple subframes. However, if a WTRU is unaware of the change in possible interference from neighbor cells, its filtering may be suboptimal and may decrease the possible throughput.
  • a cell may not be able to apply efficient link adaptation given that it may not be able to know what assumptions a WTRU uses to obtain its feedback reports.
  • IMRs may be configured by RRC signaling, so reconfiguration may be too slow to adapt to the interference landscape changes.
  • Densely deployed cells may use subsets of resources (e.g., subsets of subframes, PRBs, and/or transmission beams) to mitigate inter-cell interference. In such cases, it may be unclear how the WTRU should adapt its feedback to better represent the channel characteristics of applicable subsets of resources.
  • subsets of resources e.g., subsets of subframes, PRBs, and/or transmission beams
  • Densely deployed cells may operate in different states. For example, some cells may be active while others may be dormant. It may be beneficial to have a WTRU be served by a cell other than its best cell, to allow certain cells to be turned off and limit overall interference. To achieve such operation, load shifting may be used. A WTRU's serving cell and neighbor cell measurements may lead to incorrect triggering of reports if a WTRU is unaware of the state of neighbor cells. Methods and conditions to limit unnecessary triggering of reports may be implemented on different cells.
  • WTRUs may be statically or dynamically indicated such time instances to help them make appropriate Channel State Information (CSI) feedback.
  • CSI Channel State Information
  • patterns of state transitions may ensure that specific state transitions take place at predetermined times.
  • WTRUs may be configured with patterns of different interference periods for both CSI feedback and RSRP/RSRQ measurements. These patterns may be configured with CSI-IMs and/or CSI Processes or may be used in conjunction with CSI-IM and/or CSI Processes.
  • a WTRU may be configured with multiple sets of CSI-IMs and/or CSI Processes.
  • the WTRU may receive a dynamic indication to determine which CSI-IM and/or CSI process set is relevant at any given moment.
  • a WTRU may be configured to expect reception on a possibly dynamically changing subset of resources.
  • the WTRU may adapt its measurements to apply solely to the subset of resources. For example, wideband measurements may apply only to a subset of resources.
  • Cell biases for RSRP/RSRQ measurements may be dynamically signaled.
  • Measurement reporting may be triggered when a set of cells has a new element to report. Such reports may include the RSRP of all elements of the set.
  • New interference measurements may be reported at RRC based on measuring energy or noise over a set of resources within a subband. Triggering may be based on detecting that interference in a subband becomes better or worse than in another subband.
  • a trigger or triggers may be defined for higher layer reporting of interference.
  • SINR Signal to Interference Plus Noise Ratio
  • Channel State Information (CSI) reports for a subset or subsets of resources may enable reporting of different wideband values, possibly dependent, for multiple subsets of resources.
  • CSI Channel State Information
  • Feedback reporting may enable adaptive downlink (DL) power control.
  • a WTRU may send feedback reports that may allow small cells to configure, e.g., optimize their transmissions to reduce interference. Small cells may exchange traffic loads for enhanced small cell association.
  • a state transition for a cell may refer to a change of any parameter or defined characteristic of the cell.
  • state transitions may involve any of a variety of changes in state of a cell or cells.
  • a state transition may involve a cell or cells switching from a dormant mode to an active mode or vice versa.
  • a state transition may involve a cell or cells changing a time division duplexing (TDD) configuration.
  • TDD time division duplexing
  • a state transition may involve a cell or cells changing from one set of possible transmission or reception resources to another set or changing carrier type.
  • a state transition may involve any other change in downlink or uplink transmission that may impact the performance of a neighboring cell. When a state transition occurs in a nearby cell, channel measurements of a WTRU may be impacted.
  • a network may configure small cells with the ability to perform state transitions only at specific times (e.g., system frame number, SFN).
  • a small cell need not perform state transitions at such times if a state transition is not necessary.
  • each cell may assume that its neighbor cells share the same set of possible state transition times.
  • a cell may also be configured with a neighbor cell's set of possible state transition times.
  • a cluster of cells may be defined, and each cell within a cluster may be configured to share the same set of possible state transition times.
  • Configuration of cells with an appropriate set or sets of possible state transition times may happen, for example, via the X2 interface and may originate from a macro cell, a cluster controller entity, or a neighbor cell.
  • the configuration from a neighbor cell may be a mandate or a recommendation, which may allow the target cell the ability to accept or reject the proposed set of possible state transition times.
  • WTRUs served by cells that may have been configured with a set of possible state transition times may themselves be configured with the set or any other set that the serving cell or network deems necessary for proper operation of the WTRU.
  • a WTRU may be configured with neighbor cells' sets of possible state transition times. Such configuration may be done via higher layers, such as RRC.
  • WTRUs that are configured with sets of possible state transition times may assume that any measurements accumulated until a possible state transition time may have little or no correlation with any future measurements. These measurements may include, for example, RSRP, RSRQ, RI, CQI, and/or PMI.
  • the sets of possible state transition times that may be received either by another cell or by a WTRU may be configured as a bitmap indicating subframes or frames where such transitions may occur.
  • the sets of possible state transition times may be signaled as binary representations of actual SFN and/or subframe or subframes where transitions may occur.
  • the set of possible state transition times may be determined implicitly. For example, the set of possible state transition times may be obtained as a function of the PCI of the serving cell or a preconfigured cluster ID.
  • the set of possible transition times may be obtained as a function of an RNTI configured for a WTRU.
  • the sets of possible transition times may cover a definite period of time and may be updated at the conclusion of such a period of time. For example, after a full cycle of SFNs, a new set of possible state transition times may be configured. If a cell or a WTRU is not configured with a new set at such a time, the cell or WTRU may assume that state transitions are no longer assumed to occur. The cell or WTRU that is not configured with new sets at the end of a cycle may assume that the previous configuration should be reused, e.g., continues to be valid. Sets may be assumed to be valid until another configuration either removes any such assumptions or provides a cell or WTRU with a new set of state transition times.
  • a WTRU may be informed of upcoming possible state transition times dynamically.
  • a WTRU may assume that the possible state transition actually occurs at subframe n+k, where k may be preconfigured.
  • Such a dynamic indication may be transmitted via an information element in a Downlink Control Information (DCI) format or in MAC signaling.
  • DCI Downlink Control Information
  • a DCI format may be used with cell or cluster-specific scrambling, indicating that a possible state transition time will occur.
  • Some or all WTRUs served by a cell or by an entire cluster may be configured with the scrambling to enable them to determine the possible state transition times from a broadcast type message.
  • the resources on which such a DCI may be received by the WTRU may be preconfigured as, for example, cell-specific search-spaces.
  • the periodicity of such resources may be multiple subframes, reducing WTRU decoding complexity.
  • the resources where such a DCI may be included may be preconfigured via higher layer signaling.
  • the resources where such a DCI may be included may be determined as a function of a cell ID and/or a cluster ID.
  • a dynamic indication of a possible state transition time may be obtained from CSI request timing and may be applicable to a corresponding aperiodic CSI report. This dynamic indication may also be applicable for future aperiodic or periodic CSI report instances.
  • a WTRU may confirm reception of a state transition indication by use of a bit flag in a subsequent, e.g., its next, periodic, or aperiodic report instance.
  • a WTRU may independently determine a change in interference when making its configured measurements. For example, a WTRU may measure instantaneous interference per appropriate subframe and upon a change greater than a threshold, in possibly consecutive instantaneous interference measurements, the WTRU may independently determine that a state transition time has occurred.
  • a WTRU may be configured with a threshold value. The threshold values may be configured by higher layers (e.g., RRC) or dynamically by physical layer signaling.
  • RRC Radio Resource Control
  • a WTRU may determine sets of subframes or frames where different interference levels are seen, for example, if the difference is greater than a preconfigured threshold.
  • the WTRU may report the sets of subframes or frames to the network.
  • the WTRU may be configured to adapt its aperiodic reports to include two or more sets of CSI feedback if it determines that two or more sets of subframes or frames have different interference levels.
  • the WTRU may perform a measurement on an interference measurement resource or a set of interference measurement resources configured by higher layers and report measurement results at higher layers such as RRC. Such measurement reports may be used by the network to assist in the coordination of the use of resources between cells.
  • the measurement may include a measurement of the received power (or energy) in at least one resource element (RE) of at least one subframe and at least one resource block (PRB) or PRB pair.
  • the value may be an average over the at least one RE, subframe, and PRB, in logarithmic or linear units (e.g., dBm or mW).
  • the measurement may include an estimate of the power of noise added to a known signal.
  • the measurement may include an estimate of the signal-to-noise ratio for a known signal.
  • the measurement may replace RSSI in an RSRQ measurement in which RSRP measurement may be performed on a discovery signal, for example, instead of a cell-specific reference signal.
  • the set of REs from which a measurement is obtained may be defined as a specific set of REs within a PRB, a specific set of subframes, and/or a specific set of PRBs.
  • the set of REs within a PRB may be represented by a CSI-RS resource configuration, for instance.
  • the set of subframes may be represented by a CSI-RS subframe configuration.
  • the set of subframes may be constrained within a time period, such as a period beginning at the last state transition time if known by the WTRU, or beginning after reception of MAC or physical layer signaling indicating a change of resources to use for interference measurement.
  • the set of PRBs may be defined as a contiguous or noncontiguous set of PRBs within the carrier. For instance, a set of PRBs may coincide with a set of PRBs corresponding to a subband in CSI reporting.
  • the set of PRBs may be configured explicitly using a bitmap, for example.
  • the set of PRBs may include PRBs (e.g., all PRBs) of the carrier.
  • the sets of resources on which the interference measurements may be performed may be configured by higher layers using the configurations disclosed herein.
  • a configuration used for CSI reporting may implicitly define a set of interference measurements.
  • a set of interference measurements may implicitly be defined for a configuration of a set of subframes and REs.
  • An interference measurement may be defined for a subband out of a set of pre-defined subbands, such as the subbands used in CSI reporting.
  • a wideband measurement may be defined for the carrier. If the measurement includes an estimate of the noise added to a known signal, the WTRU may be configured with information determining the known signal, such as a non-zero-power CSI-RS configuration.
  • the WTRU may be preconfigured with multiple sets of resources for interference measurements.
  • the WTRU may be indicated from MAC or physical layer signaling (e.g., downlink control information) a specific set of interference measurements to start using, out of the preconfigured sets.
  • the WTRU may maintain at least one set of subbands for at least the purpose of event reporting. For instance, a set of high-quality subbands may be maintained, and/or a set of low- quality subbands may be maintained. These sets may be configured from higher layers or may be updated autonomously by the WTRU upon triggering of certain reports. The sets may correspond to resources within which the WTRU may report CSI.
  • the WTRU may trigger reporting of interference measurement results for a set of interference measurements at least when one of a number of events occurs.
  • the WTRU may trigger reporting of interference measurement results after expiration of a timer started at the last time a report was triggered.
  • the WTRU may trigger reporting of interference measurement results at preconfigured times, e.g., indicated from higher-layer signaling.
  • the WTRU may trigger reporting of interference measurement results after a fixed delay following the beginning of a state transition, if known by the WTRU.
  • the WTRU may trigger reporting of interference measurement results after a fixed delay following reception of MAC or physical layer signaling indicating a state transition, or a change of resources.
  • the WTRU may trigger reporting of interference measurement results upon detecting that the interference level exceeds a threshold for one subband, or over multiple subbands, e.g., all subbands. This trigger may occur if (e.g., only if) the subband is part of a set of subbands (e.g., high-quality subbands) or if (e.g., only if) the subband is not part of a set of subbands (e.g., low-quality subbands). The WTRU may then remove the subband from the set of high-quality subbands or add the subband to the set of low- quality subbands.
  • a threshold for one subband e.g., all subbands. This trigger may occur if (e.g., only if) the subband is part of a set of subbands (e.g., high-quality subbands) or if (e.g., only if) the subband is not part of a set of subbands (
  • the WTRU may trigger reporting of interference measurement results upon detecting that the interference level falls below a threshold for one subband or over multiple subbands, e.g., all subbands. This trigger may occur if (e.g., only if) the subband is part of a set of subbands (e.g., low-quality subbands), or if the subband is not part of a set of subbands (e.g., high-quality subbands). The WTRU may then remove the subband from the set of low-quality subbands or add the subband to the set of high-quality subbands.
  • a threshold for one subband or over multiple subbands e.g., all subbands. This trigger may occur if (e.g., only if) the subband is part of a set of subbands (e.g., low-quality subbands), or if the subband is not part of a set of subbands (e.g., high-quality subbands).
  • the WTRU may trigger reporting of interference measurement results upon detecting that the interference level of a first subband becomes higher than the interference level of a second subband, plus an offset. This trigger may occur if (e.g., only if) the first subband is part of a set of high-quality subbands and the second subband is not part of a set of high-quality subbands, or if (e.g., only if) the first subband is not part of a set of low-quality subbands and the second subband is part of a set of low-quality subbands.
  • the WTRU may then remove the first subband from the set of high-quality subbands and may add the second subband to the set of high-quality subbands, or may add the first subband to the set of low-quality subbands and remove the second subband from the set of low-quality subbands. This may occur if (e.g., only if) the second subband was previously the subband with the highest interference level. This may occur if (e.g., only if) the first subband was previously the subband with the lowest interference level.
  • the WTRU may trigger reporting of interference measurement reports upon detecting that the interference measured on a first set of resources exceeds the interference measured on a second set of resources, plus an offset. This trigger may occur if (e.g., only if) the measurement on the second set of resources was originally the largest and/or smallest interference
  • the trigger may occur if (e.g., only if) the measurement on the second set of resources was previously reported as being the largest and/or smallest interference measurement. This trigger may occur if (e.g., only if) the measurement on the second set of resources was originally part of a set of measurement reports and the measurement on the first set of resources was not part of the set of measurement reports. The trigger may occur if (e.g., only if) both of the measurements on the first and second sets of resources were previously reported by the WTRU.
  • a measurement report triggered according to one of the conditions disclosed herein may include interference measurement results for a set of subbands or over all subbands (e.g., wideband).
  • the set may be defined as the whole set of subbands for which a measurement is defined, or could include only the subbands concerned by the trigger.
  • the measurement report may instead or also include interference measurement results for a set of interference measurement resources, each of which may be wideband or subband measurements.
  • the set may be configured by higher layer signaling or may be configured by dynamic signaling on physical resources.
  • the set may be determined by the WTRU as the measurements that satisfy certain preconfigured criteria. For example, a WTRU may report interference measurement results for any resource that falls within a threshold from the largest or smallest interference measurement.
  • a WTRU may report interference measurement results for the best or worst x resources, where x may be preconfigured.
  • the measurement report may instead or also include RSRP measurement results for at least the same frequency (e.g., measurement object) as the resources used for the interference measurements.
  • the measurement report may instead or also include RSRQ-like measurement results for at least the same frequency (e.g., measurement object) as the resources used for the interference measurements.
  • the interference measurements may be reused as an RSSI-like measurement.
  • the measurement report may instead or also include Signal to Interference Plus Noise Ratio (SINR) measurement results for all or a subset of configured resources.
  • SINR may be obtained as one or more of a number of values.
  • the SINR may be obtained as a combination of RSRP and interference measurements.
  • the combination of resources to use for RSRP and interference measurement may be preconfigured.
  • a WTRU may be configured with a list of resources on which to make RSRP measurements or, equivalently, a desired signal power, and another list of resources on which to make interference measurements.
  • the WTRU may be configured with a measurement report indicating the combinations of RSRP or, equivalently, a desired signal power, and interference required to obtain the desired SINR measurements.
  • a WTRU may be configured with a list of SINR resources. An element of the list may include a set of resources on which to measure RSRP or, equivalently, desired signal power, and a set of resources on which to measure interference.
  • the measurement report may instead or also include a value obtained from a single resource.
  • a WTRU may obtain RSRP or, equivalently, a desired signal power, and interference values on the same set of resources and may obtain an SINR measurement for each measurement resource.
  • the measurement report may instead or also include a ratio of the desired signal power to the sum of the interference power plus an offset term.
  • the offset term in the denominator of the SINR may represent a measurement of the out-of-macro-cell-area interference and noise.
  • the measurement report may instead or also include a combination of RSRP values used for desired signal and RSRP values used as an interfering signal.
  • a WTRU may be configured to take RSRP measurements on a plurality of resources.
  • the WTRU may be configured with SINR feedback. Such configuration may indicate to the WTRU, for each SINR measurement, the RSRP to assume as the desired signal and a list of RSRP values to use as an interfering signal.
  • Another power measurement may be used instead of or in addition to RSRP measurements. Such a power measurement may be taken on a bandwidth part of the entire bandwidth.
  • a cell may not be allowed to switch states more than once per a predetermined number of frames.
  • Specific patterns of state transitions may be configured. The number of state transition patterns may be limited. A pattern may force a cell to switch states at the appropriate times. For example, if a cell may be allowed to switch between state A and state B, it may be able to do so in a limited number of patterns as shown in FIG. 2. This may limit the number of state transition instances in the overall network, and may also enable different cells to better configure their WTRUs for measurement reporting. Furthermore, by ensuring that cells switch states at preconfigured times, this approach may reduce the uncertainty that may be involved in allowing each cell to independently decide on its state in a fully dynamic manner, whether such switching is at preconfigured times or not.
  • a neighboring cell may share its state transition patterns with its neighbors.
  • the cells may transmit (e.g., via the X2 interface) the pattern to its neighbors.
  • Cells may also recommend patterns to neighbor cells, for example, to limit any negative effect on its WTRU's operation.
  • a WTRU may be configured with one or more patterns of different interference periods.
  • the pattern may be chosen at the serving cell based on, for example, a combination of state transition patterns for neighbor cells. In this example, state transitions occur at
  • appropriate interference period patterns may be configured (e.g., optimized) for a WTRU if the serving cell is made aware of the WTRU's main interferers.
  • the WTRU may indicate its main interferers to its serving cell using either explicit feedback, such as a list of interferers, or it may indicate them implicitly, such as by a list of neighbor cell RSRP.
  • the serving cell may use this information to enable it to configure appropriate CSI- IMs and/or CSI Processes.
  • a WTRU with different CSI-IMs and/or CSI Processes may be assigned such that a CSI-IM/CSI Process is defined to occur only in subframes/frames where similar interference levels are expected.
  • a WTRU may have a limited number of possible CSI-IM configurations.
  • a CSI-IM and/or CSI Process may be configured with its own pattern of interference periods. Such configuration can be done via a higher layer and may be a new information element of current CSI-IM and/or CSI Process configuration. Furthermore, CSI-IMs and/or CSI Processes may be reconfigured with patterns of interference periods. Such reconfigurations may not involve a complete reconfiguration of the CSI-IM and/or CSI Process.
  • CSI-IMs and/or CSI Processes may be configured with the same pattern of interference periods. This pattern, or measurement mask, may be used to enable the WTRU to determine what type of filter to use on measurements taken for interference for all CSI Processes.
  • the WTRU may also be configured with an explicit relation between an interference period and a periodic and/or aperiodic reporting instance. For example, if one interference period ends at subframe n, periodic or aperiodic reporting instances at subframes n+k or beyond may assume the new interference period.
  • An interference period for some or all CSI-IM and/or CSI Process may be
  • Such a dynamic indication may have a list of CSI-IM and/or CSI Processes (e.g., by using a CSI Process index) for which the WTRU may assume a new interference period has begun.
  • the dynamic indication may be performed as an implicit relationship with another configuration. For example, a WTRU may be configured with a new state of the cell. Each state of the cell may be associated with a different interference assumption. An indication of a state of a cell may implicitly configure the WTRU with an interference period for CSI-IM and/or CSI Processes.
  • the timing of a WTRU's feedback report may determine what previous measurement resources it may consider. For example, a feedback report in subframe n may be based on a CSI reference resource in subframe n-kj. Furthermore, measurements applicable to CSI reference resource in subframe n-ki may additionally depend only on any measurements taken in subframes n-k4...,n-k j .
  • the values for A3 ⁇ 4, ⁇ 3 ⁇ 4, ..kj can be configured for a WTRU and may depend on the value of n or n-kj. These values may be dynamically changed, for example, in a CSI request for aperiodic feedback.
  • a cell may be operating with a specific state transition pattern. Given that such states may include dormant mode operation, in some cases, it may not be desirable to have WTRUs filter higher layer measurements on all resources equally.
  • a WTRU may be configured with patterns of frames and/or sub frames for which it may assume different cell states and/or interference. In this case, a state/interference assumption may be for multiple frames.
  • a WTRU may assume that the measurements have little correlation to any measurements taken up until that point.
  • a WTRU may not assume that a cell is necessarily switching between only two states or that any of its neighbors are switching between only two states.
  • Such patterns may be indicated in broadcast information for each appropriate cell.
  • a WTRU may be provided with the appropriate patterns by its serving cell.
  • a WTRU may be configured with multiple sets of one or multiple CSI-IMs and/or CSI Processes each. At any given moment, one or more sets may be assumed for CSI feedback.
  • a set may be configured via higher layers (e.g., RRC configuration). For example, a
  • a configuration may include a set index as well as a list of CSI-IM and/or CSI Processes applicable to the set.
  • a configuration may include a list of CSI-IM and/or CSI Processes each with a list of indices indicating the set or sets to which each CSI-IM and/or CSI Process belongs.
  • a WTRU may be reconfigured via higher layer to add or remove a CSI-IM and/or CSI Process, e.g., with a list of sets to which the CSI-IM and/or CSI Process belongs or a set of CSI-IMs and/or CSI Processes.
  • a reconfiguration (e.g., every reconfiguration) may replace an old set of CSI-IMs and/or CSI Processes with a new set.
  • a cell may dynamically indicate to a WTRU which set of CSI-IM and/or CSI Processes it should assume for future periodic or aperiodic feedback. For example, there may be a one-to-one mapping between previous CSI Processes and new CSI Processes. In such an example, the new CSI Processes may reuse the periodic feedback configuration.
  • a CSI Process within a set may be configured with its own periodic feedback configurations (e.g., reporting mode, periodicity, and offset of reports).
  • a WTRU may feedback an indication that it has changed its set of CSI-IMs and/or CSI Processes.
  • a reporting type may be created (e.g., an acknowledgement of a switch of CSI-IM and/or CSI Process set).
  • the reporting type may be transmitted by itself in an appropriate subframe, and the new set of CSI-IMs and/or CSI
  • Processes may only be applicable to report types that occur on or after the subframe where such acknowledgement is transmitted.
  • the acknowledgement may be reported along with the RI. This may be done by creating a combination report type.
  • the cell may use an information element in a pre-existing DCI format or may use a DCI format (e.g., format 5).
  • a set of CSI-IMs and/or CSI Processes may be configured with an index, and in the DCI format, the cell may include the index of the new set of CSI-IMs and/or CSI Processes to use.
  • a WTRU may be configured with a bitmap of CSI-IM and/or CSI Processes or a set of CSI-IM and/or CSI Process. In each appropriate DCI, the bitmap may indicate the relevant CSI-IM and/or CSI Process or set of CSI-IM and/or CSI Process.
  • Each individual CSI-IM and/or CSI Process may be dynamically added or removed by indicating the CSI-IM and/or CSI Process index in the appropriate DCI.
  • Each set of CSI-IMs and/or CSI Processes may be configured with a list of interferers or conditions.
  • set 1 may be configured with interferers or conditions A, B and C
  • set 2 may be configured with interferers or conditions B and D.
  • a cell may indicate to the WTRU the set of interferers or conditions upon whose reception a WTRU may determine which set of CSI-IMs and/or CSI Processes it should use.
  • the cell may indicate the set (e.g., the entire set) of interferers or conditions in a single dynamic configuration, thus deleting any previously configured set of interferers or conditions.
  • the cell may indicate interferers or conditions A, B, and C.
  • the WTRU may, until further indication, use set 1 in its future CSI feedback reports.
  • the cell may indicate interferers or conditions B and D. Therefore, the WTRU may, until further indication, use set 2 in its future CSI feedback reports.
  • a set may be configured with a list of interferers or conditions, and a cell may use a dynamic configuration instance to add or remove interferers or conditions.
  • the WTRU may receive a second DCI indicating addition of interferer or condition D and removal of interferers or conditions A and C. After reception of such a configuration, the WTRU may, until further indication, use set 2 in its future CSI feedback reports.
  • a codepoint may exist in the DCI to instruct the WTRU that it may continue using the same CSI-IMs and/or CSI Processes. However, it may assume that any measurements made until that point may have little correlation with future measurements.
  • the dynamic indication of sets of CSI-IMs and/or CSI Processes may reuse the CSI Request bits in pre-existing DCI formats.
  • some codepoints may be configured to represent certain sets of CSI-IMs and/or CSI Processes, while one codepoint may be used to instruct the WTRU that it may continue the same CSI-IMs and/or CSI Processes; however, it may assume that any measurements made until that point may have little correlation with future measurements.
  • the dynamic indication of sets of CSI-IMs and/or CSI Processes and/or CSI-RS may be preconfigured to be tied to a dynamically configurable parameter.
  • a WTRU may be dynamically configured with a state of a cell.
  • a state of the cell may be preconfigured with a set of CSI-IMs, CSI-RSs and/or CSI Processes.
  • the WTRU may implicitly be indicated a set of CSI-IMs, CSI-RSs and/or CSI Processes.
  • the DCI may include a filtering mask to be used on one or more, e.g., all CSI-IMs and/or CSI Processes for future CSI feedback.
  • a CSI Process may be configured with a CSI-IM that occurs every fifth subframe.
  • the dynamic indication may also include a filtering mask to be used for serving cell and/or neighbor cell RSRP/RSRQ measurements.
  • a subset of subframes may be configured for CSI measurement and reporting.
  • a time division duplexing (TDD) WTRU may be configured with two types of downlink subframes. Some subframes may always be considered downlink and may be referred to as fixed downlink subframes. Other subframes, which may be referred to as flexible downlink subframes, may sometimes be used for uplink transmissions and may sometimes be used for downlink transmissions.
  • TDD time division duplexing
  • a WTRU may feedback CSI for fixed or flexible subframes.
  • a WTRU may feedback CSI for subframes where the cell may be on or off.
  • a WTRU may be connected to a cell, and in a given subframe, the cell may be downlink, uplink, or off.
  • a WTRU may be able to take CSI measurements for a cell in the off state. Such measurements may enable the eNB to (e.g., immediately) schedule a WTRU upon turning back on.
  • the WTRU may be configured with dynamic indication of the state (e.g., on or off) of the cell.
  • the WTRU may be provided a pattern of subframes where a subframe may be treated as on, off, fixed downlink, or flexible downlink.
  • a WTRU may be configured to include measurements taken in at least one of fixed downlink and/or flexible downlink or off subframes in a periodic or aperiodic CSI feedback report.
  • a WTRU may be configured with different CSI Processes for measurements that may or may not include flexible downlink subframes and/or off subframes.
  • a WTRU may be configured, e.g., dynamically, to include measurements taken in flexible downlink subframes and/or off subframes in a CSI feedback report.
  • a WTRU may be configured with a CSI Process that may include fixed downlink, flexible downlink, and/or off subframes.
  • a CSI Process may include a CSI-RS and/or CSI-IM that may cover fixed downlink, flexible downlink, and/or off subframes.
  • a CSI Process may be configured with multiple CSI-RSs and/or CSI-IMs, each of which may cover different combinations of types of subframes.
  • a WTRU may be configured with a set of CSI Processes, each with CSI-RS or CSI-IM covering different combinations of types of subframes.
  • a WTRU may be configured with a set of blanking patterns.
  • a blanking pattern may effectively remove certain subframes from consideration when a WTRU makes measurements for CSI feedback. This may be provided, for example, as a subframe restriction set or as a subframe puncturing map.
  • a blanking pattern may be configured for one or many CSI Processes, CSI-RS and/or CSI- IM
  • a CSI-IM and/or CSI-RS configuration may be applied.
  • a configuration may depend on the uplink or downlink configuration of the WTRU or may depend on an on or off state of the serving cell used by the WTRU.
  • a configuration may be ruled applicable in a certain (e.g., configured) subset of subframes that may be determined by the type of subframe.
  • the set of applicable subframes may be explicitly provided in a configuration to a WTRU, e.g., at the same time as a new uplink or downlink configuration or on or off state and/or pattern.
  • the set of applicable subframes may be determined from a combination of such a configuration and the TDD or on or off configuration provided for the WTRU.
  • a CSI-IM and/or CSI-RS configuration may imply that the CSI-IM and/or CSI-RS may be located in different types of subframes.
  • the configuration may also include an indication of any restrictions on the applicability of the CSI-IM and/or CSI-RS in certain types of subframes. For example, a CSI-IM located every fifth subframe may occur in flexible subframes.
  • the configuration may include an indication such that the WTRU knows that it will not be located in flexible subframes.
  • the indication may include a list of fixed downlink, flexible downlink, and/or off subframes where the CSI-IM and/or CSI-RS may be applicable.
  • the applicability of a CSI-IM and/or CSI-RS and/or CSI Process in different types of subframes may be configured, e.g., dynamically by an indication included in an uplink or downlink TDD configuration or reconfiguration or on or off state reconfiguration.
  • the applicability of a CSI-IM and/or CSI-RS and/or CSI Process in different types of subframes may be configured by an indication in a DCI.
  • a DCI triggering aperiodic CSI reporting may include an indication informing the WTRU of the applicability of the CSI Process and/or CSI-IM and/or CSI-RS for different types of subframes.
  • This indication may be applicable for the current aperiodic feedback report or may be applicable for future periodic and/or aperiodic feedback reports.
  • the applicability of a CSI-IM and/or CSI-RS and/or CSI Process in different types of subframes may be configured by the resources used for the PDCCH with the aperiodic trigger (e.g., whether it is a WTRU-specific search space or common search space, whether it is in PDCCH or EPDCCH, the EPDCCH resources used, and/or the DCI format used).
  • the applicability of a CSI-IM and/or CSI-RS and/or CSI Process in different types of subframes may be configured by an explicit indication of the applicable subframe type and/or subframe number or numbers for a feedback report included in a CSI feedback request.
  • the indication may include a list of subframes where CSI-IM and/or CSI-RS and/or CSI Processes may be applicable or inapplicable.
  • the indication may be provided by toggling on or off the applicability of measurements on different types of subframes, such as fixed downlink, flexible downlink, and/or off subframes.
  • the set of subframes where CSI-IM and/or CSI-RS and/or CSI Process may be applicable may be semi-statically configured via higher layer signaling.
  • an RRC message that is used to configure or reconfigure uplink or downlink patterns in the WTRU or to toggle a cell on or off or to configure or reconfigure an on/off pattern may include an indication on the applicability of measurements on different types of subframes.
  • the applicability of CSI-IM and/or CSI-RS and/or CSI Process on a set of subframes may be determined implicitly by the type of subframe where a CSI request was received. For example, if a CSI request was received in a flexible downlink or off subframe, the measurements may be performed on CSI-IM and/or CSI-RS and/or CSI Processes located in flexible downlink or off subframes.
  • the applicability of CSI-IM and/or CSI-RS and/or CSI Process on a set of subframes may be determined implicitly by the type of subframe where a CSI feedback report is included.
  • the applicability of CSI-IM and/or CSI-RS and/or CSI Process on a set of subframes may be determined implicitly by the type of feedback. For example, whether feedback is periodic or aperiodic may determine whether or not the measurement may apply to fixed downlink, flexible downlink, and/or off subframes.
  • the applicability of CSI-IM and/or CSI-RS and/or CSI Process on a set of subframes may be determined implicitly by an autonomous decision by the WTRU. For example, if measurements in flexible downlink or off subframes are within a threshold value of those in fixed downlink subframes, they may be considered jointly for feedback reports. On the other hand, if measurements in flexible downlink or off subframes are different by a threshold value from fixed downlink subframe measurements, the WTRU may autonomously decide to report two types of feedback. Depending on a priority rule or on the value of the measurement, the WTRU may report a single one of the two types of measurements.
  • some eNBs may use power backoff. Some eNBs may reduce the power of their transmission to limit errors due to physical limitations of the transmitters and/or receivers. An eNB may choose to use power backoff for WTRUs that are configured to receive HOM. An eNB may use power backoff for transmissions using HOM. The power backoff may be applied to a subset of the physical channels transmitted. For example, an eNB may use dynamic power backoff for PDSCH transmissions that use HOM.
  • HOM Higher Order Modulation
  • the eNB may use full power for other channels and/or signals in the same subframe, such as CRS, CSI-RS, (E)PDCCH, PCFICH, and/or PHICH.
  • Dynamic use of power backoff may cause demodulation of backed-off channels when estimating the channel on non-backed-off signals. Dynamic use of power backoff may affect assumptions for CSI calculations. Dynamic use of power backoff may affect
  • a WTRU may be configured with whether power backoff is used at any given moment. Such configuration may be performed by providing a WTRU with different values of P A, P_B, and/or P C for different subframes. For example, a first set of P A, P_B, and/or P C may be used for a subframe using power backoff, while a second set of P_A, P_B, and/or P_C may be used for a subframe not using power backoff.
  • the configuration may be done concurrently to being configured with possible HOM transmissions, or may be configured independently. For example, a WTRU may be indicated whether a subframe uses power backoff or not.
  • This indication may be provided dynamically (e.g., on a per frame or per subframe basis).
  • This indication may be provided using physical layer signaling indicating the status of a subframe.
  • This indication may be provided using different parameters (e.g., RE mapping or sequence generator or OCC) for reference symbols located within different types of subframes.
  • a CRS or CSI-RS may use a first sequence when power backoff is used and a second sequence when no power backoff is used.
  • the RE location of a CSI-IM may indicate whether power backoff is used or not.
  • the indication of whether a subframe uses power backoff may be provided using the existence of a certain type of signal, such as CRS, CSI-RS, and/or CSI-IM.
  • the presence of a CSI-RS may indicate to the WTRU whether power backoff is used or not.
  • the indication of whether a subframe uses power backoff may be provided implicitly by reusing a value or values of a DCI assigning PDSCH transmissions.
  • some MCS values or carrier indicator values, resource block assignment values, redundancy versions, and/or precoding information values may be tied to transmissions using or not using power backoff.
  • the configuration of the use of power backoff may be provided semi-statically.
  • a WTRU may be provided with a set of subframes where power backoff is used and another set of subframes where power backoff is not used.
  • a WTRU may be configured with a single assumption or assumptions to be used for CSI feedback to facilitate proper assumption for CSI calculation.
  • the network may adjust the CSI according to its desired transmission type.
  • a WTRU may feedback CSI values for both types of transmissions.
  • the WTRU may have different feedback report instances for each power backoff assumption.
  • the WTRU may feedback for both power backoff assumptions in a feedback report instance.
  • a CSI Process and/or CSI-RS and/or CSI-IM may be configured with a specific power backoff assumption.
  • the configuration for power backoff assumption used for demodulation may be reused for power backoff assumption for current feedback reports.
  • a WTRU may be explicitly indicated in the CSI request what power backoff assumption to use. For example, different CSI request values may be mapped to different power backoff assumptions.
  • a CSI Process may be configured with multiple CSI-IMs such that different CSI- IMs may have different neighboring cell power backoff assumptions.
  • a WTRU may be configured with different interference estimation averaging windows.
  • a window may be tied to a different power backoff from a neighboring cell.
  • Measurements may be modified for subsets of resources. Neighboring cells with high levels of inter-cell interference may coordinate their resources to limit such interference. For example, each cell may be assigned a subset of subframes and/or subcarriers/PRB/subbands and/or transmission beams, herein referred to as a subset of resources. Cells may coordinate to optimize the selection of appropriate subsets of resources. Such a coordination may be done, for example, over the X2 interface. In another example, a cell may sense its neighbors' configuration and may independently select an appropriate subset of resources, e.g., based on expected interference and cell traffic. In another example, the subset of resources of a cell may be implicitly determined as a function of the cell's PCI or of a configured virtual cell ID (VCID).
  • VCID virtual cell ID
  • the subset of resources used by a small cell may be included in a broadcast message, such as a SIB.
  • the serving small cell may configure a WTRU with higher layer signaling, the resources it may use for downlink and/or uplink traffic.
  • a serving cell may indicate via higher layer signaling a subset of subbands that may be used for downlink operation.
  • a WTRU may be configured with a bitmap parameter that links to a set of possible resources. For example, if a cell uses a subset of PRBs, such a bitmap parameter may be a PRBSubsetRestriction.
  • the cell may dynamically configure the WTRU with the appropriate subset by use of the bitmap parameter, where a ' ⁇ may indicate the sub-resource is applicable and a '0' may indicate that it is not.
  • a WTRU may be configured via higher layers with a limited list of n possible subsets of resources.
  • the cell may indicate the appropriate subset of resources using
  • a cell may configure a WTRU with multiple subsets of resources that may be considered simultaneously.
  • each CSI-IM and/or CSI Process may be configured with an appropriate subset of resources.
  • each subset of resources may be configured with its own set of CSI-IMs and/or CSI Processes.
  • some or all CSI-IMs and/or CSI Processes may be applicable to multiple subsets of resources.
  • Another example may involve feedback reporting with subsets of resources. For example, when a WTRU is configured with a subset of resources, it may perform its
  • a WTRU may assume that such a subset of resources may be considered its entire bandwidth when calculating feedback reports.
  • a WTRU may be configured with the first 20 PRBs of a carrier. In such a
  • the WTRU may assume for feedback reports that wideband measurements may be applicable only to the first 20 PRBs.
  • the WTRU may be further configured with subbands that are subsets of the 20 PRBs.
  • the RI and wideband CQI/PMI may be measured only on the configured 20 PRBs and not on the overall carrier's bandwidth. This may also be applicable for RSRP/RSRQ measurements.
  • a WTRU may be able to perform measurements on a combination of susbets. For example, a WTRU may be able to report a wideband RI that assumes the combination of multiple subsets, each of n PRBs.
  • a WTRU may be configured with multiple subsets of resources, e.g., multiple subsets of subbands.
  • a subset of resources need not include adjacent resources.
  • a subset of resources may have its own feedback mode associated with it.
  • a WTRU may report feedback values, e.g., values for RI, CQI, and/or PMI, for each subset of resources.
  • a subset of resources may have wideband feedback reports, e.g., encompassing the entire subset of resources, as well as subband reports, e.g., for a subset of subbands of the subset of resources.
  • the WTRU may also be configured to feedback reports for combinations of subsets of resources.
  • a WTRU may be configured with a first subset of resources that comprises PRBs 0, 1, 2, and 4 and a second subset of resources that comprises PRBs 3, 5, 6, and 7.
  • the WTRU may feedback independent RI values for both subsets and an RI value for the combination of the two subsets.
  • a WTRU may be configured with dependence of reports for two subsets of resources. For example, the RI value reported for a first subset of resources may depend on the RI value reported for a second subset of resources.
  • a WTRU that is configured with multiple subsets of resources may indicate to the eNB its preferred and/or least preferred subset of resources. Such an indication may be provided explicitly by feeding back a preconfigured index.
  • Some reporting instances may be configured for the preferred subset of resources.
  • the reporting instances may not always be for the same subset.
  • the WTRU may provide an indication of the appropriate subset of resources.
  • the WTRU may select a set of subsets of resources for which the WTRU will provide feedback. In such a WTRU-selected set of subsets of resources, the WTRU may include a bitmap indicating the subset of resources for which a feedback report is.
  • a dynamic indication of a subset of resources may trigger a WTRU to modify its measurements. For periodic reporting, it may not be feasible or may be impossible for a WTRU to modify its measurements for a next reporting instance. Therefore, a change in subset of resources obtained in subframe n may be applicable for all future periodic feedback reports in sub frame n+k, where k may be hard coded or may be configured via higher layer signaling. Similarly, such complexities may arise for aperiodic reporting.
  • the WTRU may be expected to provided CSI feedback in subframe n+k, where k may be greater than 4 and may be hardcoded or may be preconfigured via higher layers.
  • the subset of resources included in an aperiodic trigger may be applicable solely for that one aperiodic feedback report or may be applicable to all future aperiodic feedback reports and/or periodic feedback reports.
  • a subset of resources included in a DCI independent of an aperiodic trigger may be applicable to all future periodic and/or aperiodic feedback reports.
  • Feedback reporting may be employed to enable or facilitate downlink power control. It may be beneficial for small cells to employ adaptive power control. Each small cell may adaptively determine an appropriate value of downlink power for each transmission message. The appropriate value of downlink power may be a function of the signal strength requirements for the WTRUs served by a small cell, as well as possible interference effects on WTRUs that are not served by that small cell.
  • a WTRU may feedback values of tolerable interference for a set of neighboring points, which may be preconfigured. This may enable or facilitate adaptive downlink power control. For example, a WTRU may feedback values of STNR applicable to multiple neighboring cells, possibly with a cell identifier, to its serving cell. A WTRU may feedback a set of neighboring cells from which it is receiving levels of interference above a threshold. This threshold may be preconfigured or may be determined at the WTRU to be values that may negatively impact the reception capabilities of the WTRU.
  • the WTRU may include additional information.
  • This additional information may comprise, for example, an index for each interfering cell.
  • the additional information may comprise the interference currently affecting the WTRU.
  • This interference may comprise an absolute interference value, a SINR term, and/or a CQI term that is reinterpreted by the eNB to indicate the signal quality of the interference.
  • the additional information that may be included by the WTRU may comprise a best and/or worst partner RI, CQI, and/or PMI. This may indicate the transmission parameters that an interfering neighbor cell may use to minimize the interference to the WTRU. As another example, this may indicate the transmission parameters that most interfere with the WTRU.
  • the additional information that may be included by the WTRU may comprise a pathloss value for each interfering cell.
  • the pathloss value may be determined if the WTRU is provided with a list of transmission powers for each cell. Given that the cells may use adaptive downlink power control, the WTRU may need to be regularly updated with each cell's neighboring transmission power. The cells may use constant power on some channels and/or reference signals. This may allow a WTRU to better determine the pathloss to each cell.
  • the additional information that may be included by the WTRU may comprise a value that indicates the received interference power, the RSRP, and/or the SINR of each neighboring cell.
  • a WTRU may feedback any of these interference parameters upon feeding back RI, QCI, and/or PMI for the serving cell.
  • RI, QCI, and/or PMI There may be a dependence of the interfering parameters with the desired serving cell transmission parameters.
  • a WTRU may indicate a desired PMI for its serving cell and may couple that report with non-desired PMI values for its neighbor cells.
  • a WTRU may feedback multiple values of RI, CQI, and/or PMI. Each set of feedback values may depend on a specific measurement of interference from one or multiple neighboring cells.
  • a WTRU may be forced to connect to a cell that may not correspond to its best cell.
  • a WTRU may be configured with measurement biases.
  • a WTRU may be configured with a positive bias for its serving cell. This may limit the possibility that a WTRU may determine that a neighboring cell has a higher RSRP, thus likely forcing a WTRU to assume its current serving cell is the best.
  • a WTRU may be configured with a negative bias for a neighboring cell. This may limit the possibility that a WTRU may find such a neighbor cell to have a higher RSRP than its current serving cell.
  • a WTRU may be semi-statically or dynamically indicated cell biases for its serving cell as well as any applicable neighbor cells.
  • a WTRU may be configured with a list of biases when the network triggers measurement reports.
  • a WTRU may be configured via higher layer signaling with semi-static sets of biases to be used for future measurements and WTRU triggered reports.
  • Each WTRU may be dynamically indicated a new set of biases via DCI.
  • the biases may be completely new figures or may be a cumulative function to be used with pre-configured biases.
  • a DCI format using a set of RNTIs may be configured. Some or all WTRUs within a serving cell may be configured to monitor the DCI format using the appropriate RNTI or RNTIs.
  • Each RNTI may indicate a specific cell on which to apply the new bias (or bias delta value) included in the DCI.
  • WTRUs may be dynamically indicated whether neighbor cells are active or dormant or in any other state. Depending on the state of a neighbor cell, WTRUs may use different preconfigured biases on the measurements. The set of biases applicable to all the states of a neighbor cell may be dynamically updated.
  • a WTRU may be triggered to report measurements for a set of cells. For example, whenever a WTRU is triggered for measurement reporting, it may report measurements for its x best cells (where x may be 3, for example). Measurements reporting may be triggered, for example, when a change in the members of the set of x best cells occurs.
  • a cell to be included in the set of x best cells it may be part of a pre-configured cluster.
  • cells A, B, and C may be the three best cells of a WTRU. If a fourth cell, e.g., D, becomes offset greater than any of the cells (e.g., C), a WTRU may report measurements for cells A, B, and D only if D is also part of a preconfigured cluster.
  • Cells may provide each other with indications of traffic load. This indication may be provided, for example, via an X2 interface. For example, a first cell may indicate to a second cell that it may be able to, or may be unable to, take on more WTRUs. A cell may indicate to its neighbor the total number of WTRUs that are connected to that cell. A cell may indicate to its neighbor the number of WTRUs with active file downloads or uploads.
  • ROM read only memory
  • RAM random access memory
  • register cache memory
  • semiconductor memory devices magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs).
  • a processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

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Abstract

L'invention concerne des systèmes, des procédés et des instruments pour coordonner l'interférence dans un réseau sans fil caractérisé par un faible déploiement de cellules. Une cellule peut effectuer des transitions d'état pendant certaines périodes définies qui peuvent être des instances de temps fixes et/ou des motifs de transitions d'état. Une unité d'émission/réception sans fil (WTRU) peut être signalée en rapport avec les périodes définies. Un sous-ensemble de sous-trames peut être configuré pour établir des mesures et des rapports CSI. Une unité WTRU à duplexage par répartition dans le temps (TDD) peut être configurée avec des sous-trames de liaison descendante fixes, et des sous-trames de liaison descendante souples qui peuvent être utilisées pour des transmissions montantes ou des transmissions descendantes. Une WTRU peut assurer la rétroaction CSI pour ces sous-trames de liaison descendante souples. Ces rapports de rétroaction peuvent permettre la réduction de puissance dynamique.
PCT/US2014/032889 2013-04-03 2014-04-03 Mécanismes améliorés de coordination d'interférences pour un faible déploiement de cellules WO2014165711A1 (fr)

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US201361863082P 2013-08-07 2013-08-07
US61/863,082 2013-08-07
US201461933101P 2014-01-29 2014-01-29
US61/933,101 2014-01-29
US201461955628P 2014-03-19 2014-03-19
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CN106165474A (zh) * 2014-12-30 2016-11-23 华为技术有限公司 一种测量方法和设备
WO2017034461A1 (fr) * 2015-08-24 2017-03-02 Telefonaktiebolaget Lm Ericsson (Publ) Indication de décalage de puissance de mesure spécifique d'une modulation dans des systèmes d'accès sous licence lte
WO2017085534A1 (fr) * 2015-11-20 2017-05-26 Telefonaktiebolaget Lm Ericsson (Publ) Attribution de puissance de liaison descendante dynamique pour prise en charge d'une modulation d'ordre supérieur
CN107079324A (zh) * 2014-11-06 2017-08-18 夏普株式会社 基站装置、终端装置及通信方法
WO2018126988A1 (fr) * 2017-01-09 2018-07-12 中兴通讯股份有限公司 Procédés de rétroaction et de détermination d'informations d'état de canal, et dispositif
CN109075850A (zh) * 2016-05-12 2018-12-21 株式会社Ntt都科摩 用户装置及测量方法
CN109155928A (zh) * 2016-05-12 2019-01-04 株式会社Ntt都科摩 用户装置以及测量方法
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WO2019237043A3 (fr) * 2018-06-08 2020-01-16 Qualcomm Incorporated Rétroaction à l'aide de csi à large bande
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CN112103618A (zh) * 2020-09-09 2020-12-18 上海诺行信息技术有限公司 室外天线放置方法及系统

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