WO2014098523A1 - Procédés et appareil d'identification de petites cellules - Google Patents

Procédés et appareil d'identification de petites cellules Download PDF

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Publication number
WO2014098523A1
WO2014098523A1 PCT/KR2013/011961 KR2013011961W WO2014098523A1 WO 2014098523 A1 WO2014098523 A1 WO 2014098523A1 KR 2013011961 W KR2013011961 W KR 2013011961W WO 2014098523 A1 WO2014098523 A1 WO 2014098523A1
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WIPO (PCT)
Prior art keywords
ports
layers
drms
mapping
dmrss
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PCT/KR2013/011961
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English (en)
Inventor
Young-Han Nam
Boon Loong Ng
Krishna SAYANA
Jianzhong Zhang
Aris Papasakellariou
Original Assignee
Samsung Electronics Co., Ltd.
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Publication date
Priority claimed from US14/074,401 external-priority patent/US20140133395A1/en
Application filed by Samsung Electronics Co., Ltd. filed Critical Samsung Electronics Co., Ltd.
Publication of WO2014098523A1 publication Critical patent/WO2014098523A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0452—Multi-user MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0684—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission using different training sequences per antenna
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/26035—Maintenance of orthogonality, e.g. for signals exchanged between cells or users, or by using covering codes or sequences
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0026—Division using four or more dimensions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
    • H04L5/001—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT the frequencies being arranged in component carriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
    • H04L5/0035—Resource allocation in a cooperative multipoint environment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/14—Two-way operation using the same type of signal, i.e. duplex

Definitions

  • the present disclosure relates generally to coverage in wireless communications and, more specifically, to providing small cells having overlapping areas with other cells to improve coverage in a wireless communications system.
  • Coverage within a geographic area for a wireless communications network that is generally provided by a base station may be augmented using small cells, to increase the capacity of the wireless communications network in that area.
  • small cells For example, the service areas along roadways that are heavily traveled, or the interiors of shopping malls or sports arenas where large numbers of users may congregate, may benefit from additional capacity.
  • UE user equipment
  • Orthogonal multi-user, multiple input, multiple output (MU-MIMO) multiplexing capacity for demodulation reference signals (DMRSs) is increased without increasing the overhead in resource elements per physical resource block by using length-4 orthogonal cover codes (OCC-4).
  • a base station switches between legacy DMRS antenna port mappings and OCC-4 mapping based upon either a transmission mode or a channel station information process configuration field value.
  • a base station in a multi-user, multiple input multiple output (MU-MIMO) system comprising: a transmitter configured to transmit demodulation reference signals (DMRSs) according to a first DMRS antenna port (AP) mapping and according to a second DMRS AP mapping, wherein the base station is configured to switch between and selectively utilize one of the first and second DRMS AP mappings, the first DRMS AP mapping defined for a legacy Long Term Evolution (LTE) wireless communications standard, and the second DRMS AP mapping utilizing length 4 orthogonal cover codes (OCC-4) to multiplex orthogonal transmission of DMRSs for up to four user equipment (UEs).
  • DMRSs demodulation reference signals
  • AP DMRS antenna port
  • OCC-4 orthogonal cover codes
  • a method for transmitting demodulation reference signals (DMRSs) from a base station in a multi-user, multiple input multiple output (MU-MIMO) system comprising: transmitting DMRSs according to one of a first DMRS antenna port (AP) mapping and a second DMRS AP mapping, wherein the base station is configured to switch between and selectively utilize one of the first and second DRMS AP mappings, the first DRMS AP mapping defined for a legacy Long Term Evolution (LTE) wireless communications standard, and the second DRMS AP mapping utilizing length 4 orthogonal cover codes (OCC-4) to multiplex orthogonal transmission of DMRSs for up to four user equipment (UEs).
  • DMRSs demodulation reference signals
  • UEs user equipment
  • an user equipment (UE) in a multi-user, multiple input multiple output (MU-MIMO) system comprising: a receiver configured to receive demodulation reference signals (DMRSs) according to a first DMRS antenna port (AP) mapping and according to a second DMRS AP mapping, wherein the DMRSs are received from a base station configured to switch between and selectively utilize one of the first and second DRMS AP mappings, the first DRMS AP mapping defined for a legacy Long Term Evolution (LTE) wireless communications standard, and the second DRMS AP mapping utilizing length 4 orthogonal cover codes (OCC-4) to multiplex orthogonal transmission of DMRSs for up to four user equipment (UEs).
  • DMRSs demodulation reference signals
  • AP DMRS antenna port
  • OCC-4 orthogonal cover codes
  • a method for receiving demodulation reference signals (DMRSs) of an user equipment (UE) in a multi-user, multiple input multiple output (MU-MIMO) system comprising: a receiver configured to receive DMRSs according to a first DMRS antenna port (AP) mapping and according to a second DMRS AP mapping, wherein the DMRSs are received from a base station configured to switch between and selectively utilize one of the first and second DRMS AP mappings, the first DRMS AP mapping defined for a legacy Long Term Evolution (LTE) wireless communications standard, and the second DRMS AP mapping utilizing length 4 orthogonal cover codes (OCC-4) to multiplex orthogonal transmission of DMRSs for up to four user equipment (UEs).
  • DMRSs demodulation reference signals
  • UE user equipment
  • MU-MIMO multi-user, multiple input multiple output
  • FIGURE 1A is a high level diagram illustrating an exemplary wireless communication system within which small cell deployment may be implemented in accordance with various embodiments of the present disclosure
  • FIGURE IB is a high level block diagram of the functional components of the base station and small cells within the network of FIGURE 1 A;
  • FIGURE 1C is a front view of wireless user device employed the network of FIGURE 1A;
  • FIGURE ID is a high level block diagram of the functional components of the wireless user device of FIGURE 1C;
  • FIGURE 2 illustrates, at a high level, the initial access procedure necessary for compatibility with legacy LTE specifications
  • FIGURE 3 illustrates the primary synchronization signals (PSS)/secondary synchronization signals (SSS)/PBCH resource element (RE) mapping necessary for compatibility with legacy (Rel-8, 9, 10) LTE systems;
  • PSS primary synchronization signals
  • SSS secondary synchronization signals
  • RE resource element
  • FIGURE 4 is an illustration of the three options for implementation of new carriers types (NCTs);
  • FIGURES 5A and 5B illustrate two cases for an NCT cell to neighbor a backward compatible cell
  • FIGURES 6A and 6B illustrate signal diagrams for a quasi-cell in accordance with the present disclosure co-channel deployed with an NCT cell and with a backward compatible cell, respectively;
  • FIGURE 7 illustrates signal diagrams for a convertible-type cell in accordance with the present disclosure
  • FIGURES 8A, 8B and 8C illustrate network configuration snapshots for the small cells in order to achieve energy saving and to adapt the operation based upon the UE-type population in accordance with the present disclosure
  • FIGURE 9 illustrates the resource elements used for UE-specific reference signals for normal cyclic prefix for antenna ports 7, 8, 9 and 10 for one specification
  • FIGURE 10 illustrates mapping of UE-specific reference signals to resource elements of a resource block (with normal cyclic prefix) according to one embodiment of the present disclosure
  • FIGURES 11A through 1 ID illustrate UE-specific Reference Signal (UE-RS) power boosting aspects of employing reduced-overhead UE-specific reference signals according to one embodiment of the present disclosure
  • FIGURE 12 illustrates switching among different reduced-overhead UE-RS patterns when employing reduced-overhead UE-specific reference signals according to one embodiment of the present disclosure.
  • FIGURES 1 through 12 discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless communication system.
  • the following documents and standards descriptions are hereby incorporated into the present disclosure as if fully set forth herein:
  • 3GPP TR 36.932 [REF4] describes target scenarios of a small-cell study, indicating that small cell enhancement should target deployment both with and without macro coverage, both outdoor and indoor small cell deployments, and both ideal and non-ideal backhaul. In addition, both sparse and dense small cell deployments should be considered.
  • FIGURE 1 A is a high level diagram illustrating an exemplary network within which small cell deployment may be implemented in accordance with various embodiments of the present disclosure.
  • FIGURE 1 A illustrates small cell deployment with/without macro coverage, where Fl and F2 are the carrier frequencies for the macro layer and the local-node layer, respectively.
  • the network 100 of FIGURE 1 A includes a base station 101, also sometimes referred to as an access point or an evolved Node B ("eNodeB" or "eNB”), providing wireless communications with fixed or mobile user devices within a coverage area corresponding to macro cell regions 102a- 102c.
  • eNodeB evolved Node B
  • Three generally equally-sized macro cell regions or "sectors" 102a- 102c are depicted in FIGURE 1A, although the number and size of such coverage area regions may vary for different implementations.
  • additional wireless small cells 103a-103n may be established with coverage at least partially overlapping that of base station 101 or augmenting.
  • Each small cell 103a-103n has a structure functionally similar to that of base station 101 and operates in a similar manner.
  • the small cells 103a-103n operate in conjunction with base station 101 and with each other in the manner described in further detail below to improve wireless communications service for user equipment (UE) operating within the geographic coverage area of base station 101 or within an extended coverage area provided by small cells 103a-103n.
  • UE user equipment
  • One or more user device(s) (not shown in FIGURE 1A), which may also be referred to as user equipment (UE) or a mobile station (MS), are located within the coverage area of base station 101 and/or with the coverage areas of small cells 103a-103n.
  • the user device(s) may be either fixed or mobile, and accordingly may comprise a "smart" phone or tablet device capable of functions other than wireless voice or data communications or may be a laptop or desktop computer, a video receiver, or other wireless device.
  • the mobile user devices may move within the coverage area of base station 101 and within or between the coverage areas of small cells 103a-103n.
  • Coverage area regions 102a- 102c in FIGURE 1A are depicted as coverage using "macro" layers operating using frequency Fl while small cells 103a-103n are depicted as "local-node” layers operating using frequency F2.
  • the coverage area regions 102a- 102c are positioned and operate with substantially contiguous (i.e., only slightly overlapping) coverage areas while small cells 103a-103n are positioned and operate with coverage areas either completely non-overlapping with the coverage area regions 102a- 102c, partially overlapping with such coverage area regions, or fully overlapping such coverage area regions.
  • the coverage area regions 102a-102c and coverage areas of small cells 103a and 103g-103n may be completely or partially within a building, depicted as wire frame rectangular boxes in FIGURE 1A.
  • FIGURE IB is a high level block diagram of the functional components of the base station and small cells from the network of FIGURE 1A
  • FIGURE 1C is a front view of wireless user device (or user equipment) that may be employed within the network of FIGURE 1A
  • FIGURE ID is a high level block diagram of the functional components of that wireless user device.
  • Base station 101 and each small cell 103a-103n includes one or more processor(s) 1 10 coupled to a network connection 1 1 1 over which signals may be received and selectively transmitted - that is, a connection to a backhaul network and/or to the Internet.
  • the base station 101 and each small cell 103a-103n also includes memory 1 12 containing an instruction sequence for processing communications in the manner described below, and data used in the processing of communications.
  • the base station 101 and each small cell 103a-103n each further include a transceiver 113 and associated antenna(a) 114 for wireless communications with user equipment.
  • the transceiver 113 may further include a transmitter and a receiver.
  • User device(s) (or user equipment) 105 is a mobile phone with wireless data communications capabilities in an exemplary embodiment and includes a display 120 on which user controls may be displayed.
  • a processor 121 coupled to the display 120 controls operation of the user device.
  • the processor 121 controls operation of a transceiver 124 according to embodiments for user equipments in the specification.
  • the transceiver 124 may further include a transmitter and a receiver.
  • the processor 121 and other components within the user device 105 are either powered by a battery (not shown), which may be recharged by an external power source (also not shown), or alternatively by the external power source.
  • a memory 122 coupled to the processor 121 may store or buffer instructions and content for wireless communications with any of base station 101 and small cells 103a-103n.
  • User controls e.g., buttons or touch screen controls displayed on the display 120
  • buttons or touch screen controls displayed on the display 120 are employed by the user to control the operation of mobile device 105 in accordance with known techniques.
  • small cell enhancement should target deployment in which small cell nodes 103a-103n are deployed under the coverage of one or more than one overlaid Evolved Universal Terrestrial Radio Access Network (E-UTRAN) macro-cell layer(s) 102a- 102c in order to boost the capacity of already deployed cellular network.
  • E-UTRAN Evolved Universal Terrestrial Radio Access Network
  • the UE is in coverage of both the macro cell and the small cell simultaneously;
  • the UE is not in coverage of both the macro cell and the small cell simultaneously (e.g., in the coverage area of the macro cell only).
  • FIGURE 1A also shows the scenario where small cell nodes 103a and 103k-103n are not deployed even partially under the coverage of one or more overlaid E-UTRAN macro-cell layer(s) 102a- 102c. This scenario is also the target of the small cell enhancement. SPARSE AND DENSE
  • Small cell enhancement should consider sparse and dense small cell deployments.
  • some scenarios e.g., hotspot indoor/outdoor places, etc.
  • only a single or a few small cell node(s) are sparsely deployed, for example to cover the traffic hotspot(s).
  • dense urban residential areas, a large shopping mall, etc. a lot of small cell nodes are densely deployed to support huge traffic over a relatively wide area covered by the small cell nodes.
  • smooth future extension/scalability e.g.,: from sparse to dense, from small-area dense to large-area dense, or from normal-dense to super-dense
  • dense deployments should be prioritized compared to sparse deployments.
  • both sparse and dense deployments should be considered with equal priority.
  • Both synchronized and un-synchronized scenarios should be considered between small cells as well as between small cell and macro layers.
  • small cell enhancement can benefit from synchronized deployments with respect to small cell search/measurements and interference/resource management. Therefore time synchronized deployments of small cell clusters are preferably prioritized and new means to achieve such synchronization should be considered.
  • Small cell enhancement should address the deployment scenario in which different frequency bands are separately assigned to macro layer and small cell layer, respectively, where Fl and F2 correspond to different carriers in different frequency bands as described above.
  • Small cell enhancement should be applicable to all existing and as well as future cellular bands, with special focus on higher frequency bands, e.g., the 3.5 giga-Hertz (GHz) band, to enjoy the more available spectrum and wider bandwidth.
  • higher frequency bands e.g., the 3.5 giga-Hertz (GHz) band
  • Small cell enhancement should also take into account the possibility for frequency bands that, at least locally, are only used for small cell deployments. Co-channel deployment scenarios between macro layer and small cell layer should be considered as well. The duplication of activities with existing and coming standards items should be avoided.
  • One potential co-channel deployment scenario is dense outdoor co-channel small cells deployment, considering low mobility UEs and non-ideal backhaul, where all small cells are under the macro coverage.
  • Small cell enhancement should be supported irrespective of duplex schemes ⁇ frequency division duplex (FDD) or time division duplex (“TDD”) — for the frequency bands for macro layer and small cell layer.
  • FDD frequency division duplex
  • TDD time division duplex
  • Air interface and solutions for small cell enhancement should be band-independent, and aggregated bandwidth per small cell should be no more than 100 mega- Hertz (MHz), at least for Rel-12.
  • FIGURE 2 illustrates, at a high level, the initial access procedure necessary for compatibility with legacy LTE specifications in accordance with embodiments of the present disclosure.
  • the process 200 begins with UE power up (step 201), frequency and time synchronization, then downlink synchronization and acquisition of the physical layer (PHY) cell identification (ID) (step 202).
  • PHY physical layer
  • ID cell identification
  • Legacy UEs acquire system information block 1 (SIB1) and system information block 2 (SIB2) (step 205), which are in the Physical Downlink Shared CHannel (PDSCH), after decoding the Physical Broadcast CHannel (PBCH), acquiring control information using the Physical Control Format Indicator CHannel (PCFICH) (step 203), and acquiring shared channel resources based on the Physical Downlink Control CHannel (PDCCH) (step 204).
  • SIB1 includes information on operator identification (ID), cell barring, etc.
  • SIB2 includes information on the random access configuration.
  • FIGURE 3 illustrates the primary synchronization signals (PSS)/secondary synchronization signals (SSS)/PBCH resource element (RE) mapping necessary for compatibility with legacy (Rel-8, 9, 10) LTE systems.
  • Each (vertical) group of resource blocks (RBs) depicts the middle six RBs from a subframe within which PSS/SSS are transmitted, with the topmost and bottommost RBs in FIGURE 3 being part of the remainder of the RBs within the respective subframe.
  • the leftmost group is an FDD configuration (subframe 0); the center group is a TDD configuration (subframe 1) used for configuration 1, 2 6 or 7; and the rightmost group is another TDD configuration (subframe 0).
  • the location of resource elements (REs) allocated to the PBCH, PSS, SSS and CRS Port 0 are shown for the respective configurations.
  • RP-121186 proposes introduction of dormant cells in the following manner:
  • NCT new carriers types
  • Option 1 Reduced common reference signal (CRS) (Rel-11 NCT), (useful mainly in macro cells);
  • FIGURE 4 is an illustration of the three options described above. A high level comparison of the three schemes described above is provided in TABLE I below:
  • Tx circuitry is switched On/Off on a per-subframe basis rather than on a per-symbol basis.
  • MBSFN Multicast-Broadcast Single-Frequency Network
  • DM-RS DeModulation Reference Signals
  • Rl- 124931 two cases were identified for an NCT cell to neighbor a backward compatible cell (e.g., Rl 1 compatible cell), as shown in FIGURES 5A and 5B.
  • a backward compatible cell e.g., Rl 1 compatible cell
  • FIGURES 5A and 5B two cases were identified for an NCT cell to neighbor a backward compatible cell (e.g., Rl 1 compatible cell), as shown in FIGURES 5A and 5B.
  • Pcell primary cell
  • Fl carrier frequency f cl
  • F2 secondary cell
  • FIGURES 6A and 6B illustrate signal diagrams for a quasi-cell in accordance with the present disclosure co-channel deployed with an NCT cell and with a backward compatible cell, respectively.
  • a backward compatible type (BCT) cell/sub frame refers to a subframe/cell complying with the legacy specification (i.e., at least one of 3GPP LTE Release 8, 9, 10, 11).
  • FIGURES 6A and 6B illustrating signaling for a quasi-cell (e.g., a small cell 103a-103n) that is co-channel deployed on a carrier (or a carrier frequency) together with a cell (e.g., base station 101); the quasi-cell and the cell may have been placed in two geographically separated locations.
  • a quasi-cell is identified by a quasi-cell specific discovery signal (and discovery ID), depicted as the bottom signal sequences including periodic subframes with a discovery signal, for example transmitted without PSS/SSS and PCI, transmitted on a different frequency band than used for the PDSCH of legacy UEs with overlapping coverage, and/or transmitted with a coding not recognized by legacy UEs.
  • An advanced UE can identify a quasi-cell by detecting a quasi-cell specific discovery signal, while a legacy UE cannot identify the quasi-cell.
  • the network can make use of the quasi-cell to transmit PDSCH to both the legacy UE and the advanced UE.
  • the advanced UE may then be aware that the advanced UE receives the PDSCH from the quasi-cell.
  • the quasi-cell operation is transparent to the legacy UE, and the legacy UE does not recognize or know of the existence of the quasi-cell as the legacy UE operates according to the legacy specification where no specific protocols are defined for the quasi-cells. It is noted that the quasi-cell is not a traditional cell, as the quasi-cell does not carry PSS/SSS to be used for identifying the cell and physical cell ID (PCI).
  • PCI physical cell ID
  • the advanced UE When the cell is configured to an advanced UE as an Scell, the advanced UE synchronizes to the Scell (and to the quasi-cell when the quasi-cell is close to the Scell) relying on PSS/SSS, and may receive other configurations with respect to the Scell from the Pcell.
  • the advanced UE can be configured to receive PDSCH and other downlink (DL) physical signals from either the cell or the quasi-cell or both.
  • the advanced UE can be configured with two virtual cell IDs (VCIDs), one (VCID1) for the cell and the other (VCID2) for the quasi-cell.
  • VCID1 is used for PDSCH and/or UE-RS scrambling for the PDSCH.
  • VCID2 is used for PDSCH and/or UE-RS scrambling for the PDSCH.
  • the configuration of the DL physical signal origin can change either dynamically or semi-statically.
  • a one-bit field can included in a DL scheduling assignment DCI format (e.g., DCI formats 1 A, 2B, 2C, 2D and any extension of these DCI formats) to indicate the DL physical signal origin, i.e., whether the DL physical signal is from the cell (in which case VCID1) or the quasi-cell (in which case VCID2).
  • a DL scheduling assignment DCI format e.g., DCI formats 1 A, 2B, 2C, 2D and any extension of these DCI formats
  • quasi-cells are co-channel deployed on a first carrier with a cell that is an NCT cell carrying PSS/SSS/Timing Reference Signal (TRS).
  • a serving cell on the first carrier can be configured as an Scell for the advanced UEs.
  • a BCT serving cell on a second carrier can be a Pcell for the legacy UEs and the advanced UEs and that BCT serving cell provides the basic coverage.
  • the legacy UEs can only access the cell on the second carrier, while the advanced UEs can access both the first and the second carriers.
  • quasi-cells are co-channel deployed on a first carrier with a cell that is a BCT (e.g., Rl 1) cell.
  • a serving cell on the first carrier can be configured as an Scell or a Pcell for both the advanced UEs and the legacy UEs.
  • a BCT serving cell on a second carrier can be a Pcell for both the legacy UEs and the advanced UEs and provide the basic coverage.
  • the deployment scenario shown in FIGURE 6A can provide cleaner and more performance-optimal designs for the NCT.
  • the deployment scenario shown in FIGURE 6B has a benefit of being backward compatible, so that legacy UEs can also access the carrier frequency where the quasi-cells are co-channel deployed.
  • the quasi-cell carries PSS/SSS, where the PSS/SSS sequences are identical to those of the legacy LTE carrier (or Rel-8 compliant during the initial access), but the time location—that is, the Orthogonal Frequency Division Modulation (OFDM) symbol numbers to carry PSS/SSS— could be different from those for the legacy LTE carrier.
  • the macro layer(s) can be deployed as either a legacy (one of 3GPP LTE Rel-8, Rel-9, Rel-10 and Rel-11) LTE cell (FIGURE 6B) or a new-carrier-type (NCT) cell (FIGURE 6A).
  • the quasi-cell may not carry PSS/SSS, but may instead carry a discovery signal for helping advanced UEs discovering the quasi-cells.
  • an advanced UE can acquire synchronization to the quasi-cell relying on PSS/SSS (and TRS or CRS) transmitted by the quasi-cell.
  • PSS/SSS and TRS or CRS
  • the advanced UE obtains a physical cell ID (PCI) and cyclic prefix (CP) length (e.g., whether the CP length is normal-CP or extended-CP).
  • PCI physical cell ID
  • CP cyclic prefix
  • the advanced UE relies on the discovery signal transmitted by the quasi-cell. Once the UE discovers a quasi-cell relying on the discovery signal, the UE obtains a discovery ID.
  • a discovery ID is used to generate at least one of a set of time-frequency locations where a discovery channel is transmitted and the (scrambling) sequence for the discovery signal.
  • the UE can identify the existence of a quasi-cell having the discovery ID (using the sequence).
  • the discovery ID detected from the discovery signals would be able to have wider range of values than otherwise available.
  • the value range for the discovery ID is chosen as [0, MSCI], where MSCI is the maximum possible value for the discovery ID, which is greater than 503, e.g., 2006.
  • the value range for the discovery ID is chosen as [504, MSCI], where MSCI is the maximum possible value for the discovery ID.
  • the advanced UE may acquire synchronization by listening to the PSS/SSS/TRS transmitted by the macro, but at the same time the advanced UE may receive/transmit physical signals (e.g., PDSCH, PUSCH, ePDCCH, SRS, etc.) from/to a nearby quasi-cell.
  • the advanced UEs can be configured with a number of virtual cell IDs according to one of the following alternative methods:
  • a virtual cell ID (VCID) to replace physical cell IDs in at least one of the following occasions is determined by a function of the discovery ID and the PCI.
  • a virtual cell ID (VCID) to replace physical cell IDs in at least one of the following occasions is explicitly radio resource control (RRC) configured.
  • RRC radio resource control
  • Scrambling initialization of the physical DL/UL signals enhanced Packet Data Control CHannel or "ePDCCH,” Physical Downlink Shared CHannel or “PDSCH,” Physical Uplink Shared CHannel or "PUSCH”).
  • UL uplink
  • RS reference signal
  • group hopping (for UL DMRS, sounding reference signals (SRS) and Physical Uplink Control CHannel (PUCCH)).
  • VCID PCI + (discovery ID), where the range of discovery ID is [504,
  • VCID PCI + (discovery ID) » 29, where the range of discovery ID is [0,
  • FIGURE 7 illustrates that a new type of cell called "convertible-type cell,” in which a small cell can switch cell (subframe) types between NCT and BCT for periods of time.
  • This change in cell types allows a cell to opportunistically operate in a backward compatible manner only when necessary, thereby reducing the network's energy consumption and the inter-cell interference.
  • PSS/SSS/TRS on the NCT can be transmitted in the identical way as the PSS/SSS/CRS are transmitted on the backward compatible cell. In this case, the RSRP measurement should be based upon TRS (or reduced CRS).
  • the subframe can be either an MBSFN subframe or a non-MBSFN subframe.
  • CRSs are transmitted only in the first two OFDM symbols of the subframe
  • non-MBSFN subframe full CRSs are transmitted according to the CRS pattern for Antenna Ports (APs) 0-NAP, where NAP is the number of configured CRS APs.
  • APs Antenna Ports
  • NAP is the number of configured CRS APs.
  • PDCCH, PCFICH and Physical Hybrid-Automatic Repeat request (ARQ) Indicator CHannel (PHICH) are transmitted in the first a few OFDM symbols of the subframe.
  • the subframe type is NCT and when the subframe does not carry PSS/SSS, no CRSs are mapped in the subframe.
  • no CRSs are mapped in the subframe.
  • none of PDCCH, PCFICH and PHICH are transmitted, and hence PDSCH can be transmitted from the first OFDM symbol.
  • the legacy UE relies on the legacy mechanism of performing RSRP measurement on the NCT small cell.
  • the legacy UE may be able to perform the RSRP measurement, even though the legacy UE may assume that the small cell is actually a backward compatible cell and may try to measure RSRP in those subframes where CRS is not transmitted.
  • the RSRP measured by the legacy UE is likely to be distorted (in fact, to be degraded), and some of the legacy UE's RSRP reporting triggering conditions may not be satisfied even if the NCT cell is nearby.
  • the network can determine that the legacy UE is proximate to the NCT small cell. To allow for the legacy UEs to receive/transmit from/to the small cell when the legacy UE is nearby, the network can convert the cell type of the small cell from the NCT to BCT (backward-compatible small cell), or use a subset of subframes for the backward compatible transmissions (partially backward-compatible small cell).
  • BCT backward-compatible small cell
  • legacy CRS(s) may be transmitted to support the legacy PDCCH transmission and legacy TMs relying on legacy CRS.
  • the legacy rate matching of the PDSCH (around the CRS REs) for the legacy UEs can be applied, even if the legacy CRS is not transmitted.
  • the network can configure an Scell for an advanced UE that is a convertible-type cell.
  • the type of Scell can be either explicitly indicated by an information element conveyed by an RRC signal configuring the Scell or implicitly indicated by the OFDM symbol location of PSS/SSS (in case the OFDM symbol location of PSS/SSS in the convertible-type cell is different from the BCT cells).
  • the information element can be of the ENUMERATION type, and the possible information element values would be codes for ⁇ BCT, NCT, CT ⁇ , where CT implies convertible-type.
  • the advanced UEs are aware that the small cell is a convertible type cell.
  • the system protocol may therefore be designed so that the advanced UEs take advantage of the knowledge of the cell type.
  • the advanced UE knows the cell (or subframe) type, the advanced UEs can:
  • Method Y Perform PDSCH rate matching differently depending upon the cell (or subframe) type (Method Y).
  • CQI channel quality information
  • the subframe type can be indicated to the advanced UE so that the advanced UE can apply the proper method.
  • the indication of the subframe type can be done in a UE-specific RRC configuration containing a 40-bit bitmap field, the z ' -th bit of which indicates whether the z ' -th subframe of a super-frame of N sup er (e-g-> 40) subframes is BCT or NCT. For example, if the z ' -th bit is 1, the z ' -th subframe is NCT; if the z ' -th bit is 0, the z ' -th subframe is BCT.
  • the TRS in the NCT is transmitted on the resource elements (REs) where the legacy CRS for AP 0 is transmitted.
  • the number of CRS ports should not vary over subframes.
  • the number of CRS APs in the BCT cell (or subframe) should be constant, which is 1.
  • the cell-type switching can happen only in an Scell on a first carrier, and a UE maintains a basic connection with the network in a Pcell on a second carrier.
  • the eNB 100 configures an SCell that is a convertible type (between NCT and backward-compatible-type) for the advanced UE, the number of CRS APs in BCT subframes in the convertible-type cell is constant, i.e., one.
  • Method X When the cell type is either NCT or convertible-type, the advanced UEs should perform RSRP measurement only in those subframes where PSS/SSS/TRS are transmitted, and rely on TRS (or reduced CRS); on the other hand, when the cell type is BCT, the advanced UEs can rely on the legacy mechanism to perform RSRP measurement without any subframe restriction. A few alternatives to inform the advanced UEs of the cell type are considered below.
  • the subframes where PSS/SSS/TRS are transmitted are subframes #0 and #5.
  • the following pseudo-code is captured for the E-UTRA measurement object, i.e., MeasObjectEUTRA information element (IE):
  • MeasObjectEUTRA SEQUENCE ⁇
  • PresenceAntennaPort 1 PresenceAntennaPort 1
  • CellsToAddModList :: SEQUENCE (SIZE (L.maxCellMeas)) OF CellsToAddMod
  • CellsToAddMod may be modified to include the cell type of each neighbor cell.
  • NCTIndicator is TRUE if the cell is NCT or convertible-type, FALSE if the cell is BCT.
  • cellType is NCT if the cell is NCT or convertible-type, backwardCompatible if the cell is BCT.
  • the type of the neighbor cell is implicitly indicated by the time location of PSS/SSS.
  • the UE detects PSS/SSS according to the legacy specification (or according to FIGURE 3)
  • the UE determines that the cell is BCT.
  • the UE detects PSS/SSS in a different pair of OFDM symbols than the pair of OFDM symbols allocated for PSS/SSS in the legacy specification (or according to FIGURE 3)
  • the UE determines the cell is NCT.
  • Method Y When the cell (or subframe) type is NCT, the advanced UE should read PDSCH symbols from the first OFDM symbol (OFDM symbol 0 in the first time slot) within the assigned Physical Resource Blocks (PRBs); furthermore, in those subframes where TRS is not transmitted, the advanced UE does not apply rate matching around CRS.
  • the cell (or subframe) type is BCT, the advanced UE should read PDSCH symbols from the configured OFDM symbol number within the assigned PRBs with rate matching around the PDCCH region and CRS REs (according to the MBSFN subframe configuration).
  • the configured OFDM symbol number is indicated to the advanced UE by at least one of the following alternatives:
  • the advanced UE decodes PCFICH, which indicates the starting OFDM symbol number for the PDSCH.
  • the advanced UE is signaled by an RRC configuration which indicates the starting OFDM symbol number for the PDSCH.
  • the advanced UE When an advanced UE is configured with Transmission Mode 10 (TM10), the advanced UE receives a 2-bit field indicating rate matching pattern. Considering the operation in the convertible-type cell, it makes sense that the advanced UE's behavior changes depending upon the subframe type.
  • the subframe-type is BCT
  • the UE follows Rel-11 specification for the rate matching (i.e., PDSCH symbols are rate matched around PDCCH region); on the other hand, when the subframe-type is NCT, the UE reads the PDSCH symbols from the first OFDM symbol in the first time slot; furthermore, in those subframes where TRS is not transmitted, the advanced UE does not apply rate matching around CRS.
  • Method Z Depending on the cell (or subframe) type, the advanced UE calculate CQI differently. In BCT subframes (or cells), when deriving the CQI index, some of the UE assumptions for the CSI resource are:
  • the ratio of PDSCH Energy Per Resource Element (EPRE) to Channel State Information Reference Signal (CSI-RS) EPRE is as given in Section 7.2.5 of 3GPP TS 36.213;
  • CRS REs are the same as those in non-MBSFN subframes.
  • NCT subframes or cells
  • the UE assumptions above for the CSI reference resource are modified for the NCT subframes (cells) as follows: Zero OFDM symbols are occupied by control signaling (since conventional PDCCH is not transmitted).
  • CP length is that of the non-MBSFN subframes.
  • Redundancy Version 0 is employed.
  • the ratio of PDSCH EPRE to CSI-RS EPRE is given by P c .
  • P c is the assumed ratio of PDSCH EPRE to CSI-RS EPRE when UE derives CSI feedback and takes values in the range of [-8, 15] dB with 1 dB step size, for all the OFDM symbols in the subframe.
  • Transmission Mode 8 (TM8) is supported, for CSI reporting, no CRS REs are assumed in the CSI reference resource (since no CRS may exist in the extension carrier).
  • the UE-specific reference signal overhead is consistent with the most recent reported rank; and PDSCH signals on antenna ports ⁇ 7 . . .6 + v ⁇ for v layers would result in signals equivalent to corresponding symbols transmitted on antenna ports ⁇ 15 . . .
  • x(Q ⁇ ⁇ ( ⁇ -1) ( ⁇ )]
  • ⁇ is a vector of symbols from the layer mapping in section 6.3.3.2 of 3GPP TS 36.21 1
  • P 6 ⁇ 1,2,4,8 ⁇ is the number of CSI-RS ports configured, and if only one CSI-RS port is configured, W (t) is 1 but otherwise W(i) is the precoding matrix corresponding to the reported PMI applicable to x(i).
  • the corresponding PDSCH signals transmitted on antenna ports ⁇ 15 . . . 14 + P ⁇ would have a ratio of EPRE to CSI-RS EPRE equal to the ratio given in section 7.2.5 of 3GPP TS 36.21 1.
  • the PDSCH transmission scheme (TS) assumed for CSI reference resource for TM8 or TM9 is given in Table 2 of 3GPP TS 36.211.
  • the basic DM-RS transmission scheme (TS) for CSI-feedback can be: Option 1 : Fixed and predefined, e.g. single antenna port transmission scheme using DM RS port 7, or Transmit diversity scheme based on DM RS port(s), e.g. port 7 and port 8.
  • Option 2 configurable by higher layer signaling (see Table 3).
  • Option 3 Same as the basic DM-RS TS configured/defined for PDSCH demodulation as described in Embodiment 1 (see Table 4).
  • the basic DM-RS TS for CSI feedback is Basic DM-RS TS 1 , i.e., the single-antenna port transmission scheme using DM-RS port 7, the CSI is derived as if only one CSI-RS port is configured, relying only on antenna port 15.
  • the basic DM-RS TS for CSI feedback is Basic DM-RS TS 2, i.e., the transmit diversity transmission scheme using DM-RS ports 7 and 8, the CSI is derived under the following two assumptions:
  • Channels estimated on CSI-RS port 15 are the same as channels estimated on DM-RS port 7;
  • Channels estimated on CSI-RS port 16 are the same as channels estimated on DM-RS port 8.
  • PDSCH signals on antenna ports ⁇ 7,8 ⁇ for 2 layers would result in signals equivalent to corresponding symbols transmitted on antenna ports ⁇ 15,16 ⁇ , as given by
  • this embodiment also extends to other TMs supported in the extension carrier.
  • Basic DM-RS TS 1, e.g. single antenna port transmission
  • Basic DM-RS TS 2 e.g. transmit diversity scheme based on
  • DM RS port(s) e.g. port 7 and port 8
  • the transmission scheme of PDSCH uses DM RS ports (7-8 for TM8 and 7-14 for TM9) when the PDCCH uses downlink control information (DCI) format 2B and 2C, respectively.
  • DCI format 1A the transmission scheme in Rel-10 may use CRS ports (see Table 7.1-5 in 3GPP TS 36.213).
  • TM8 and/or TM9 are supported in the extension carrier, in order to support PDSCH transmission using DCI format 1A in the NCT cell (or subframe), for TM8 and/or 9, a transmission scheme that uses DM RS ports is always used for PDSCH transmission using DCI format 1A, hereafter referred to as the basic DM-RS transmission scheme (TS). Note that this proposal extends to any transmission modes that are supported in the NCT cell (or subframe).
  • Base DM-RS TS 1 Single antenna port transmission scheme using DM RS port 7 is used for PDSCH transmission scheduled using DCI format 1 A.
  • One example for the single antenna port transmission scheme is precoding cycling for each resource blocks where, e.g., the precoder applied (on DM RS port and the data) can be different for different resource blocks (in frequency).
  • the UE may not assume PRB (physical resource block) bundling when receiving the PDSCH using the basic DM-RS TS, regardless of whether PMI/RI feedback is configured (relevant for transmission mode 9 as there is no support for PRB bundling for transmission mode 8).
  • the condition for UE to assume PRB bundling is applied as described in Sec 7.1.6.5 of Sec 36.213 is modified as follows:
  • the UE may assume that precoding granularity is multiple resource blocks in the frequency domain when PMI/RI feedback is configured and if the transmission scheme is not Basic DM-RS TS 1, which can be implied by the type of DCI format used for PDSCH scheduling, e.g. DCI format 1A can indicate that the transmission scheme is Basic DM-RS TS 1.
  • the single antenna port transmission scheme is precoding cycling for each resource element (RE).
  • precoding may not be applied on the DM RS and is applied only on the data.
  • the precoding applied to the data for every RE can be predefined and known at both the eNB and the UE.
  • Base DM-RS TS 2 Transmit diversity scheme based on DM RS port(s), e.g. port 7 and port 8.
  • SFBC Space Frequency Block Coding
  • FIGURES 8A, 8B and 8C illustrate network configuration snapshots for the small cells in order to achieve energy saving and to adapt the operation based upon the UE-type population.
  • UEs maintain basic mobility on a Pcell that is BCT, and receive/transmit data mainly on the Scell that is convertible-type (CT).
  • CT convertible-type
  • FIGURE 8A depicts a network configuration during the busy hours, where the network turns on all the small cell eNBs SI, S2, S3 and S4 to serve the large UE population.
  • the small cell eNBs can be configured as CT, so that some legacy UEs can be served in the small cells as well as the advanced UEs.
  • FIGURE 8B depicts the network configuration during the off-peak hours, where the network turns off some small cells SI, S3 for energy saving.
  • FIGURE 8C depicts a network configuration of the CT small cells during the off-peak hours, where the network configures one Scell S2 to be BCT and another Scell S4 to be NCT, depending on the UE population that each small cell covers.
  • S4 serves only the advanced UEs
  • S4 is operating as NCT
  • S2 is operating as BCT at least in a subset of subframes.
  • the network may make decision to convert the network configuration from FIGURE 8 A to FIGURE 8B based upon the network detecting that the number of UEs connected to each cell is smaller than a threshold.
  • the coverage of each turned-on cell i.e., S2 and S4
  • the coverage of each turned-on cell may increase as inter-cell interference decreases. This is true especially when the cells S2 and S4 do not change transmission power according to the network configuration.
  • the network may make a decision to convert the network configuration from FIGURE 8B to FIGURE 8A when the network detects that the number of UEs connected to each cell is larger than a threshold.
  • the network may re-configure the Scell for the UE, from SI to S2, so that the UE receives/transmits data mainly to S2.
  • a part of the reference signal sequence r(m) shall be mapped to complex-valued modulation symbols a ⁇ in a subframe according to
  • FIGURE 9 illustrates the resource elements used for UE-specific reference signals for normal cyclic prefix for antenna ports 7, 8, 9 and 10.
  • downlink bandwidth is less than or equal to 10 PRBs, there is no resource allocation header and resource allocation type 0 is assumed.
  • Nl RB bits provide the resource allocation
  • n SCID is the scrambling identity for antenna ports 7 and 8 defined in section 6.10.3.1 of [REF1]
  • transport block 1 is mapped to codeword 0; and transport block 2 is mapped to codeword 1.
  • the transport block to codeword mapping is specified according to Table 5.3.3.1.5 2.
  • Value 4, 5, 6 in TABLE VI below are only supported for retransmission of the corresponding transport block if that transport block has previously been transmitted using two, three or four layers, respectively.
  • the following information is transmitted by means of the DCI format 2D: . . . (Same field descriptions as in Format 2C until redundancy version for transport block 2)
  • transport block 1 is mapped to codeword 0; and transport block 2 is mapped to codeword 1.
  • the transport block to codeword mapping is specified according to Table 5.3.3.1.5 2.
  • Value 4, 5, 6 in Table 2 are only supported for retransmission of the corresponding transport block if that transport block has previously been transmitted using two, three or four layers, respectively.
  • a UE configured in transmission mode 10 for a given serving cell can be configured with up to 4 parameter sets by higher layer signaling to decode PDSCH according to a detected PDCCH/EPDCCH with DCI format 2D intended for the UE and the given serving cell.
  • the UE shall use the parameter set according to the value of the 'PDSCH RE Mapping and Quasi-Co-Location indicator' field (mapping defined in TABLE VII below) in the detected PDCCH/EPDCCH with DCI format 2D for determining the PDSCH RE mapping (defined in Section 6.3.5 of [REFl]) and PDSCH antenna port quasi co-location (defined in Section 7.1.10).
  • the UE shall use the parameter set indicated in the PDCCH/EPDCCH with DCI format 2D corresponding to the associated SPS activation for determining the PDSCH RE mapping (defined in Section 6.3,5 of [REFl]) and PDSCH antenna port quasi co-location (defined in Section 7.1.10).
  • the following parameters for determining PDSCH RE mapping and PDSCH antenna port quasi co-location are configured via higher layer signaling for each parameter set:
  • a UE configured in transmission mode 10 for a given serving cell can be configured with a parameter set selected from the four parameter sets in TABLE VII by higher layer signaling for determining the PDSCH RE mapping (defined in Section 6.3.5 of [REFl]) and PDSCH antenna port quasi co-location (defined in Section 7.1.10) to decode PDSCH according to a detected PDCCH/EPDCCH with DCI format 1A intended for the UE and the given serving cell.
  • the PDSCH RE mapping defined in Section 6.3.5 of [REFl]
  • PDSCH antenna port quasi co-location defined in Section 7.1.
  • the UE shall use the configured parameter set, determining the PDSCH RE mapping (defined in Section 6.3.5 of [REF1]) and PDSCH antenna port quasi co-location (defined in Section 7.1.10) for decoding PDSCH corresponding to detected PDCCH/EPDCCH with DCI format 1A and PDSCH without a corresponding PDCCH associated with SPS activation indicated in PDCCH/EPDCCH with DCI format 1 A.
  • a UE configured in transmission mode 1-10 may assume the antenna ports 0 - 3 of a serving cell are quasi co-located (as defined in [REF1]) with respect to delay spread, Doppler spread, Doppler shift, average gain, and average delay.
  • a UE configured in transmission mode 8-10 may assume the antenna ports 7 - 14 of a serving cell are quasi co-located (as defined in [REF1]) for a given subframe with respect to delay spread, Doppler spread, Doppler shift, average gain, and average delay.
  • a UE configured in transmission mode 1-9 may assume the antenna ports 0 - 3, 5, 7 - 22 of a serving cell are quasi co-located (as defined in [REF1]) with respect to Doppler shift, Doppler spread, average delay, and delay spread.
  • a UE configured in transmission mode 10 is configured with one of two quasi co-location types by higher layer signaling to decode PDSCH according to transmission scheme associated with antenna ports 7-14:
  • Type A The UE may assume the antenna ports 0 - 3, 7 - 22 of a serving cell are quasi co-located (as defined in [REF1]) with respect to delay spread, Doppler spread, Doppler shift, and average delay
  • Type B The UE may assume the antenna ports 15 - 22 corresponding to the CSI-RS resource configuration identified by 'CSI-RS resource configuration identity for PDSCH RE mapping' in Section 7.1.9 and the antenna ports 7 - 14 associated with the PDSCH are quasi co-located (as defined in [REF1]) with respect to Doppler shift, Doppler spread, average delay, and delay spread.
  • Two antenna ports are said to be quasi co-located if the large-scale properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed.
  • the large-scale properties include one or more of delay spread, Doppler spread, Doppler shift, average gain, and average delay.
  • a demodulation reference signal associated with EPDCCH is not transmitted in resource elements ( , I) in which one of the physical channels or physical signals other than the demodulation reference signals defined in 6.1 are transmitted using resource elements with the same index pair (k, V) regardless of their antenna port p.
  • the reference-signal sequence r(m) is defined by
  • the pseudo-random sequence c(i) is defined in Section 7.2.
  • the pseudo-random sequence generator shall be initialized with
  • the EPDCCH set to which the EPDCCH associated with the demodulation reference signal belong is denoted t e ⁇ 0,1 ⁇ .
  • a part of the reference signal sequence r(m) shall be mapped to complex-valued modulation symbols a in a subframe according to
  • Replacing antenna port numbers 7 - 10 by 107 - 110 in FIGURE 9 provides an illustration of the resource elements used for demodulation reference signals associated with EPDCCH for normal cyclic prefix.
  • the UE For a given serving cell, if the UE is configured via higher layer signalling to receive PDSCH data transmissions according to transmission mode 10, and if the UE is configured to monitor EPDCCH, for each EPDCCH-PRB-set, the UE shall use the parameter set indicated by the higher layer parameter re-MappingQCLConfigListld-rl 1 for determining the EPDCCH RE mapping (defined in Section 6.8A.5 of [REF1]) and EPDCCH antenna port quasi co-location.
  • the following parameters for determining EPDCCH RE mapping and EPDCCH antenna port quasi co-location are included in the parameter set:
  • MCS modulation and coding scheme
  • FIGURE 9 and TABLE V respectively describe UE-RS (or DMRS) patterns and orthogonal cover codes (OCCs) for APs 7 to 14 in Rel-10 3 GPP LTE standards.
  • TABLE VI explains a field in DCI formats 2C and 2D, which indicates antenna port(s), scrambling identity (SCID) and number of layers.
  • SCID scrambling identity
  • the interpretation of the 3 -bit field is different depending upon how many codewords (CWs) are enabled.
  • the 3-bit field can indicate one of 7 possibilities comprising one-layer, two-layer, three-layer and four-layer transmissions.
  • the 7 states four of those states indicate one-layer transmissions, on (AP 7, SCID 0), (AP 7, SCID 1), (AP 8, SCID 0) and (AP 8, SCID 1).
  • the other three states indicate two-layer, three-layer and four-layer transmissions that are used only for retransmission of a single CW, out of two initially transmitted CWs in a previous subframe.
  • the 3 -bit field can indicate one of 8 possibilities comprising 2-8 layer transmissions.
  • two of those states indicate two-layer transmissions, on (AP 7-8, SCID 0) and (AP 7-8, SCID 1).
  • the other six states indicate 3-8 layer transmissions.
  • the 3 GPP LTE Rel-10 supports multi-user multiple input, multiple output (MU-MIMO) transmissions. Up to four layers can be multiplexed in a MU-MIMO transmission, relying on APs 7-8 and SCIDs 0-1.
  • eNB may configure (AP 7, SCID 0), (AP 7, SCID 1), (AP 8, SCID 0) and (AP 8, SCID 1) to the 4 UEs, relying on the indication mechanism of TABLE VI.
  • a UE configured with (AP 7, SCID 0) may see intra-cell interference on the DMRS REs, corresponding to (AP 7, SCID 1), (AP 8, SCID 0) and (AP 8, SCID 1).
  • the interference caused by DMRS of (AP 8, SCID 0) is likely to be orthogonal to the DMRS of (AP 7, SCID 0) thanks to the OCCs used for APs 7 and 8.
  • the interference caused by DMRS of (AP 7, SCID 1) and (AP 8, SCID 1) is not orthogonal because of the different scrambling sequence generated by SCID 1.
  • [REF5] introduces a field jointly indicating the number of layers (antenna ports), the pilot resource allocation (AP numbers), and SU/MU MIMO. However, [REF5] did not disclose which codepoints to use in a DCI to indicate the information.
  • SU-MIMO and MU-MIMO are non-transparently indicated here (for example, state 0 is identical to state 8 except for MU-MIMO and SU-MIMO difference), which reduces scheduling flexibility.
  • state 0 is identical to state 8 except for MU-MIMO and SU-MIMO difference
  • Rel-10 support MU-MIMO multiplexing of up to 4 layers it may not be practically feasible for a UE to deal with the non-orthogonal interference in case the UE is co-scheduled with other UEs configured with the a scrambling ID.
  • [REF5] proposed to apply length-4 Walsh cover to the 4 REs on the same subcarrier, and support MU-MIMO multiplexing of up to 4 layers with corresponding 4 orthogonal DMRS.
  • the 4 DMRS REs on the same subcarrier are partitioned into two groups of two time-consecutive REs, and the two groups are separated by a few OFDM symbols. Because of this time separation of the two groups, the DMRS orthogonality when four UEs are co-scheduled may be broken, especially in the case some UEs are moving in high-speed. However, when all the four UEs are low speed, the four DMRS REs are more likely orthogonal, and the length-4 Walsh cover can be considered when only low speed UEs are considered for MU-MIMO multiplexing.
  • length-4 Walsh covers can be considered for keeping DMRS overhead low while at the same time achieving the orthogonal DMRS for the 3 or 4 layers.
  • This disclosure describes methods for an eNB to indicate information to UEs involved in the SU-MIMO and MU-MIMO transmissions with the 4 orthogonal DMRS on the set of 12 REs for AP 7.
  • the 4 orthogonal DMRS are associated with AP 7, AP 8, AP 11 and AP 13.
  • Embodiment 1 Enhancement for MU-MIMO
  • n3 ⁇ 4 MRS can dynamically change, depending upon the value of nSCID, as in the following (Section 6.10.3.1 in [REFl]):
  • the pseudo-random sequence generator shall be initialised with
  • Cinit Q n V 2 J + !) ⁇ ( 2n l ( D SC,D) + ⁇ * + "SCID at the start of each subframe.
  • -n p N j D 11 if no value for n ⁇ MRS ' 1 is provided by higher layers or if DCI format 1A, 2B or 2C is used for the DCI associated with the PDSCH transmission, and
  • n SCID is zero unless specified otherwise.
  • Alt 1 No dynamic switching of VCIDs when four orthogonal DMRS is configured for MU-MIMO
  • a first alternative (Alt 1) is proposed: that for the UE configured with the four orthogonal DMRS for MU-MIMO, a single value of DMRS VCID, ⁇ i ) MRS , is configured, and the UE generates scrambling initialization as in the following:
  • Cinit ( ⁇ 2 ] + ! ) * + * 2
  • n ID N j 1 if no value for is provided by higher layers or if DCI format
  • n lD nTM* otherwise.
  • the UE when 1 or 2 layer transmission is signaled to a UE, the UE should assume DMRS overhead of 12 REs for PDSCH rate matching, demodulation and CQI estimation; and the UE should assume traffic-to-pilot ratio of 0 dB.
  • Alt 2 we propose to introduce a new way to dynamically indicate nj3 ⁇ 4 MRS , by including or re-interpreting a one-bit field in a new DCI format for scheduling PDSCH coupled with the four orthogonal DMRS.
  • Alt 2-1 The DI of disabled TB (a one-bit field) indicates n, D D MRS .
  • Alt 2-2 A new explicit one-bit field is included in the new DCI format for scheduling PDSCH, to indicate nP D MRS .
  • number of layers and antenna port(s) can be indicated as in the new signaling table design in TABLE X.
  • Embodiment 2 Enhancement for SU-MIMO
  • length-4 Walsh cover for SU-MIMO is for overhead reduction.
  • Embodiment 3 Enhancement for SU-MIMO and MU-MIMO
  • a new signaling table can be defined to support length-4 Walsh cover transmissions for MU-MIMO and SU-MIMO with rank 3 and 4, as in TABLE XII below:
  • AP_Layer_Config_R12 An explicit one-bit field to indicate which table to use.
  • PQI may include table index, to facilitate dynamic switching between two tables, i.e. the information on which table to use by the UE is jointly coded with the other existing PQI information.
  • Benefit 1 (Scheduling flexibility) Use legacy table for MU-MIMO multiplexing with legacy UEs; Use new table for MU-MIMO multiplexing between R12 UEs.
  • Embodiment 4 Configuration details (TM definition, CSI-RS, CSI process, PQI, etc.)
  • a new TM can be defined to support the use of a transmission scheme relying on length-4 Walsh covers for SU MU-MIMO (e.g., transmission schemes associated with Embodiment 1, 2 and 3).
  • Which table out of two tables, i.e., the legacy table (TABLE VI) and a new table (one of TABLE X, TABLE XI and TABLE XII), should be used for determining number of layers, antenna port(s), and scrambling ID, may be indicated by a configured transmission mode. For example, when TM 9 or 10 is configured for a UE, the UE should use TABLE VI; on the other hand when TM A is configured, the UE should use the new table.
  • the DMRS overhead assumption associated with 3 or 4 layers changes upon which of the two tables is used.
  • the last reported rank is 3 or 4.
  • the DMRS overhead is 24 REs; on the other hand, when the new table is used, the DMRS overhead is 12 REs.
  • a first alternative to configure the DMRS overhead assumption would be to couple the assumption with the configured TM.
  • the UE should assume the new table for the DMRS overhead assumption in the CSI (CQI) derivation for all the configured CSI processes; while when the UE is configured with TM 9 or 10, the UE should assume TABLE VI for the DMRS overhead assumption in the CSI (CQI) derivation for all the configured CSI processes.
  • the CSI process information element includes a field to indicate which table to assume to account for the DMRS overhead for rank 3 and rank 4.
  • the new CSI process is defined as in the following:
  • p-C-AndAntennalnfoDedList-rl 1 SEQUENCE (SIZE (1..2)) OF P-C-AndAntennalnfoDed-rl 1,
  • the Rel-11 CSI process can be extended as in the following.
  • the new field can be conditioned on the configuration of TM A.
  • p-C-AndAntennalnfoDedList-rl 1 SEQUENCE (SIZE (1..2)) OF P-C-AndAntennalnfoDed-r 11 ,
  • the state of the field cqi-OverheadRank3Rank4 indicates whether to assume 12 RE overhead (re 12) or 24 RE overhead (re24) for the configured CSI process when report CQI associated with rank 3 or rank 4 PMI.
  • the new CSI process is defined as in the following:
  • the Rel-1 1 CSI process can also be extended as follows.
  • the new field can be conditioned on the configuration of TM A.
  • CSI-Process-rl l SEQUENCE ⁇ csi-ProcessIdentity-rl 1 CSI-ProcessIdentity-rl 1, cqi-ReportAperiodicPS-rl 1 CQI-ReportAperiodicPS-rl 1 OPTIONAL, Need OR
  • the state of the field antennaPortTable indicates whether to use TABLE VI or the new table to take the DMRS overhead into account in deriving CQI associated with rank 3 or rank 4 PMI.
  • cqi-OverheadRank3Rank4 or antennaPortTable is included as a field in PDSCH-RE-MappingQCL-Config, as shown below:
  • crs-PortsCount-rl 1 ENUMERATED ⁇ nl, n2, n4, sparel ⁇ , crs-FreqShift-rl 1 INTEGER (0..5),
  • crs-PortsCount-r 1 1 ENUMERATED ⁇ n 1 , n2, n4, spare 1 ⁇ , crs-FreqShift-rl 1 INTEGER (0..5),
  • PDSCH-RE-MappingQCL-Config-rl 1 SEQUENCE ⁇ pdsch-RE-MappingQCL-Configld-rl 1
  • PDSCH-RE-MappingQCL-Config corresponds to a parameter set in TABLE VII, and hence a UE can be configured with up to four separate PDSCH-RE-MappingQCL-Config information elements. Then, the selection of table can be dynamically indicated by PQI carried as a field in a DL grant (DCI format 2D).
  • DCI format 2D DL grant
  • One benefit of configuring antennaPortTable field in PDSCH-RE-MappingQCL-Config is better scheduling flexibility. With this, eNB can dynamically change user pairing, either by using legacy table for MU-MIMO multiplexing with legacy UEs, or by using the new table for MU-MIMO multiplexing among R12 UEs.
  • TM A the antenna port allocation is done according to one of TABLE X, TABLE XI and TABLE XII. In that case, the indicated numbers of antenna ports may not be consecutive, especially when 3 or 4 layers are scheduled.
  • the precoding method is dependent upon the configured TM.
  • precoding For transmission on a single antenna port, precoding is defined by
  • Precoding for spatial multiplexing using antenna ports with cell-specific reference signals Precoding for spatial multiplexing using antenna ports with UE-specific reference signals is only used in combination with layer mapping for spatial multiplexing as described in Section 6.3.3.2 of [REF1].
  • the precoding operation is defined by
  • the precoding operation is defined by
  • the length-4 Walsh covers can be considered for multiplexing four ePDCCH DMRS in the set of DMRS REs for AP 107, for reducing ePDCCH DMRS overhead.
  • whether to use the length-4 Walsh covers or to use the legacy APs should be able to be UE-specifically configured for each ePDCCH set (or EPDCCH-PRB-set) according to a parameter signaled in the RRC layer.
  • FIGURE 9 provides an illustration of the resource elements used for demodulation reference signals associated with EPDCCH for normal cyclic prefix.
  • APs 107 and 108 are used.
  • a field ap-mapping-ePDCCH can be configured in the RRC layer, which is ENUMERATED ⁇ ap-107-108- 109-110 or ap-107-108-111-113 ⁇ , where ap-107-108-109-110 implies that antenna ports 107-110 are used for EPDCCH, and ap-107-108-1 1 1-1 13 implies that antenna ports 107, 108, 111, 1 13 are used for EPDCCH.
  • the UE should assume that the DMRS overhead is 24 REs, according to the DMRS RE mapping associated with APs 107-1 10.
  • the UE should assume that the DMRS overhead is 12 REs, according to the DMRS RE mapping associated with APs 107,108,111 and 113.
  • [REF6] shows that demodulation performance of PDSCH relying on a reduced-overhead UE-RS outperforms the performance relying on a legacy UE-RS generated according to Rel-10 3GPP LTE standards, especially for PDSCH with higher MCS and higher rank. Based upon this observation, it may be useful to introduce reduced-overhead UE-RS for small cells where higher SNR can be obtained.
  • This disclosure describes proposals for introducing reduced-overhead UE-RS for small cells in the 3 GPP LTE standards.
  • reduced-overhead UE-RS can be configured to an advanced UE capable of receiving/transmitting signals according to 3GPP LTE standards.
  • number of REs per PRB pair used for the reduced-overhead UE-RS is smaller than that of legacy UE-RS REs.
  • FIGURE 10 illustrates mapping of UE-specific reference signals to resource elements of a resource block (with normal cyclic prefix) according to one embodiment of the present disclosure.
  • One example reduced-overhead UE-RS mapping is shown in FIGURE 10, where the first four APs for reduced overhead UE-RS are denoted by a, b, c, d.
  • the eight APs for the reduced-overhead UE-RS are denoted by a, b, c, d, e,f, g, and h.
  • a first set of REs used for UE-RS APs a, b are also used for APs e, g.
  • a second set of REs used for UE-RS APs c, d are also used for APs h.
  • the Walsh cover applied for each antenna port is captured in TABLE XIII below:
  • a UE can be configured with a new one-bit message conveyed in the higher-layer (e.g., RRC layer), wherein if the new one-bit message is a first state (e.g., 0), the UE is configured to receive PDSCH with the legacy UE-RS and if the new one-bit message is a second state (e.g., 1), the UE is configured to receive PDSCH with the reduced-overhead UE-RS.
  • the higher-layer e.g., RRC layer
  • a UE can be configured with a new transmission mode (TM), say TM X, which supports transmission schemes relying on a reduced-overhead UE-RS.
  • TM transmission mode
  • Two alternatives are considered below, for the PDSCH reception of a UE configured with TM X: Alt 1) When a UE is configured with TM X, the UE receives PDSCH with reduced-overhead UE-RS.
  • the UE-RS indication when the second condition is met, the UE-RS indication is done according to the legacy specification (i.e., according to TABLE VI); when the first condition is met, the UE-RS indication is done according to TABLE XV below:
  • the reduced-overhead UE-RS When the reduced-overhead UE-RS is used for rank 1 and 2, the reduced UE-RS can be used for MU-MIMO as well as single user MIMO (SU-MIMO).
  • SU-MIMO single user MIMO
  • the reduced-overhead UE-RS may significantly degrade channel estimation performance when UE-RS are multiplexed with different scrambling IDs, because the interference randomization relying on scrambling may not be effective with the small number of UE-RS REs.
  • removal of scrambling ID indication may be considered when reduced-overhead UE-RS is used.
  • nscw 0 is always assumed for scrambling initialization, and the antenna port indication can be performed according to either TABLE XVI or XVII below instead of TABLE XV, when reduced-overhead UE-RS is configured.
  • n VCID is introduced for indicating a virtual cell ID (VCID) out of two higher-configured VCIDs.
  • the pseudo-random sequence generator for the UE-RS sequence shall be initialised with
  • Alt 2 is motivated by the fact that reduced-overhead UE-RS is advantageous when signal-to-interference-plus-noise ratio (SINR) is high, and/or MCS is high, and/or rank is high; at the same time the reduced-overhead UE-RS may hurt the performance otherwise. According to these motivations, it may make sense to switch UE-RS patterns according to Method 1 as in the following.
  • SINR signal-to-interference-plus-noise ratio
  • Method 1 The switching conditions for the UE-RS patterns depend on at least one of MCS and rank.
  • the first and the second conditions are defined as at least one of threshold numbers associated with MCS and rank.
  • Example J When a UE is configured with TM X, the UE receives PDSCH with reduced-overhead UE-RS if the MCS configured in the PDCCH scheduling the PDSCH is greater than or equal to M; with legacy UE-RS if the MCS is less than M.
  • the UE is indicated to use antenna ports according to the legacy table (i.e., TABLE VI) if the MCS is less than M, and according to the new table (i.e., one of TABLE XII, TABLE XIII and TABLE XIV) if the MCS is greater than or equal to M.
  • the legacy table i.e., TABLE VI
  • the new table i.e., one of TABLE XII, TABLE XIII and TABLE XIV
  • Example 2 When a UE is configured with TM X, the UE receives PDSCH with reduced-overhead UE-RS if the rank configured in the PDCCH scheduling the PDSCH is greater than or equal to R; with legacy UE-RS if the rank is less than R.
  • R 3.
  • APs 7 and 8 are used; the 8 APs for reduced overhead UE-RS are denoted by a, b, c, d, e,f, g, h and are used only when the rank is greater than or equal to 3.
  • the legacy antenna port indication table of TABLE VI can be revised into a new table as shown in TABLE XVIII below:
  • Example 3 When a UE is configured with TM X, the UE receives PDSCH with reduced-overhead UE-RS if the rank configured in the PDCCH scheduling the PDSCH is equal to R and the MCS is greater than or equal to or if the rank is greater than R; with legacy UE-RS if the rank is less than R or if the rank is equal to R and the MCS is less than M.
  • the UE is indicated to use antenna ports according to the legacy table (i.e., TABLE VI) if the rank is less than R or if the rank is equal to R and the MCS is less than M, and according to the new table (i.e., one of TABLE XV, TABLE XVI and TABLE XVIII) if the rank is equal to R and the MCS is greater than or equal to or if the rank is greater than R.
  • the legacy table i.e., TABLE VI
  • the new table i.e., one of TABLE XV, TABLE XVI and TABLE XVIII
  • Example 4 The UE receives PDSCH with reduced-overhead UE-RS if both codewords are enabled and both MCS indices (I M cs) f° r me two CWs are greater than or equal to M, where is an integer; with legacy UE-RS otherwise.
  • M is chosen such that 64 quadrature amplitude modulation (64QAM) is transmitted.
  • M 28, which is the maximum MCS index associated with 64QAM. This option is motivated from observation that reduced overhead DMRS achieves a better throughput than the legacy DMRS when the rank is high and 64QAM are chosen for both CWs.
  • Method 2 The switching conditions for the UE-RS patterns depend on whether a UE is indicated to use antenna ports that support MU-MIMO or not.
  • the MU-MIMO codepoints i.e., Values 0-3 for one-CW enabled case, and Values 0-1 for two-CW enabled case, are kept the same as the legacy table, i.e., TABLE VI.
  • n SCID 1 3 4 layers, ports a, b, c, d
  • Method 3 For ensuring the best flexibility of eNodeB operation, a new one-bit field can be introduced in the DCI format scheduling the PDSCH (i.e., DCI format 2B/2C/2D and any DCI formats derived from these formats) for indicating a UE-RS out of the two.
  • the indication of UE-RS is performed according to the following table.
  • Method 4 Alternatively, for ensuring some flexibility of eNodeB operation and at the same time to reduce the PHY-layer signaling overhead, the UE-RS pattern information (TABLE XI) can be carried along with quasi co-location (QCL) information, which is included in the PDSCH RE Mapping and Quasi-Co-Location indicator (PQI) field in the DCI format 2D.
  • QCL quasi co-location
  • PQI Quasi-Co-Location indicator
  • the following parameters for determining PDSCH RE mapping and PDSCH antenna port quasi co-location are configured via higher layer signaling for each parameter set:
  • the 'UE-RS pattern information' can indicate one of multiple configured UE-RS patterns.
  • the multiple configured UE-RS patterns are the legacy UE-RS and a reduced-overhead UE-RS.
  • the multiple configured UE-RS patterns are the legacy UE-RS and the NCT UE-RS.
  • the multiple configured UE-RS patterns are the legacy UE-RS, a reduced-overhead UE-RS and the NCT UE-RS.
  • the multiple configured UE-RS patterns are the legacy UE-RS, a first reduced-overhead UE-RS and a second redued-overhead UE-RS.
  • the multiple configured UE-RS patterns are at least two of Patterns 1, 2, 3 and 4 in TABLE XXI or TABLE XXII below.
  • Method 5 The channel estimation performance of reduced- overhead UE-RS can be improved when PRB bundling is applied. Hence, it is proposed that PRB bundling is always assumed when reduced-overhead UE-RS is configured. When PRB bundling is configured precoding granularity is multiple resource blocks in the frequency domain.
  • a serving cell of a first or a second type can be configured to an advanced UE capable of receiving/transmitting signals according to 3 GPP LTE standards.
  • the first type is the legacy carrier type (LCT) serving cell
  • the second type is the NCT serving cell.
  • the advanced UE can be configured with reduced-overhead UE-RS.
  • the advanced UE should support potentially four UE-RS patterns, i.e., Patterns 1, 2, 3 and 4 as shown in TABLE XVIII. Depending on the combination of the configurations, the UE support one out of the four patterns. For example, if the UE is configured with a serving cell of LCT, and the UE is configured with reduced overhead, the UE should assume Pattern 2 for PDSCH demodulation. It is noted that the UE-RS overhead configuration (or configuration of whether to use legacy or reduced-overhead UE-RS) can be performed according to some of the examples considered in embodiment 1.
  • Pattern 1 is the same as the Rel-10 UE-RS pattern, depicted in FIGURE 9.
  • An example of Pattern 2 is depicted in FIGURE 10.
  • Patterns 3 and 4 should be designed such that the UE-RS do not collide with PSS/SSS.
  • Pattern 2 is designed such that it also does not collide with PSS/SSS
  • Pattern 4 can be the same as Pattern 2.
  • UE-RS pattern configuration for the advanced UEs would look like TABLE XIX. .
  • FIGURES 1 1 A through 1 ID explain UE-RS power boosting aspects of employing reduced-overhead UE-specific reference signals according to one embodiment of the present disclosure.
  • the number of REs per OFDM symbol per PRB pair is 12.
  • the total available power in each OFDM symbol in a PRB pair is 12P.
  • each UE-RS RE and each PDSCH RE are assigned with the same power, i.e., P. This relation is illustrated in FIGURE 11 A.
  • the total available power in each OFDM symbol in a PRB pair is 12P.
  • each UE RS RE has power 2P
  • each PDSCH RE has power P
  • 3x2P + 6xP 12P. This relation is illustrated in FIGURE 1 IB.
  • the UE may assume the ratio of PDSCH EPRE to UE-specific RS EPRE within each OFDM symbol containing UE-specific RSs is 0 dB.
  • the UE may assume the ratio of PDSCH EPRE to UE-specific RS EPRE within each OFDM symbol containing UE-specific RS is 0 dB for number of transmission layers less than or equal to two and -3 dB otherwise.
  • power boosting may be applied to the reduced-overhead UE-RS as illustrated in FIGURE 11D, e.g., so that the same total power as in the legacy UE-RS can be kept in the OFDM symbol. Then, especially in relatively frequency-flat and time-flat channels, almost the same channel estimation performance may be achieved with the reduced-overhead UE-RS as the legacy UE-RS. At the same time, total power allocated to the PDSCH is maintained the same as the case of legacy UE-RS, but the number of REs allocated for the PDSCH increases. The increased number of REs for PDSCH may give us further coding gain, which may increase performance overall, regardless of high-SNR or not.
  • An advanced UE can be configured with traffic-to-pilot power ratio (or PDSCH EPRE to UE-RS EPRE power ratio) in the higher-layer signaling (RRC signaling), which indicates x decibels (dB) to assume for the traffic-to-pilot power ratio.
  • RRC signaling indicates x decibels (dB) to assume for the traffic-to-pilot power ratio.
  • the advanced UE assumes the configured power ratio when a reduced-overhead UE-RS is used; the advanced UE assumes the legacy power ratio when the legacy UE-RS is used.
  • the indication of reduced-overhead UE-RS can be performed according to the methods in embodiments 1 and 2.
  • the RRC signaling message can indicate one dB value out of two values, e.g., ⁇ 3dB, 6dB ⁇ .
  • Method 7 The advanced UE assumes x dB power traffic-to-pilot power ratio when a reduced-overhead UE-RS is used, where x is (Alt 1) a constant or (Alt 2) determined as a function of the rank; the advanced UE assumes the legacy power ratio when the legacy UE-RS is used.
  • the indication of reduced-overhead UE-RS can be performed according to the methods in embodiments 1 and 2.
  • This example ensures that the UE-RS in the reduced-overhead UE-RS pattern has the same total power as the UE-RS in the legacy pattern.
  • EVM inter-modulation/error vector magnitude
  • a UE-specific reduced-overhead UE-RS pattern may be allocated.
  • Method 8 An advanced UE can be instructed to use a reduced-overhead UE-RS pattern out of a number of candidate reduced-overhead UE-RS patterns.
  • Example 1 The UE can be instructed to use one out of three candidate reduced-overhead UE-RS patterns.
  • FIGURE 12 illustrates the three patterns in this example. The figure illustrates 12 REs in each OFDM with UE-RS within a PRB pair. When configured with a reduced-overhead UE-RS pattern, all the four OFDM symbols with UE-RS will be generated according to the reduced overhead UE-RS mapping pattern.
  • Alt 1 RRC configuration message (information element or information field).
  • Alt 4 The pattern is configured as one parameter for each PQI parameter set (as in Method 4).

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Abstract

La présente invention concerne l'augmentation d'une capacité de multiplexage orthogonal multi-utilisateurs à entrées multiples et sorties multiples (MU-MIMO) pour des signaux de référence de démodulation (DMRS) sans augmenter la surcharge en éléments de ressources pour chaque bloc de ressource physique, au moyen de codes de couverture orthogonale de longueur 4 (OCC-4). Selon l'invention, une station de base commute entre des mappages de ports d'antenne DMRS existants sur la base soit d'un mode de transmission, soit d'une valeur de champ de configuration de processus d'information de station de canal.
PCT/KR2013/011961 2012-12-21 2013-12-20 Procédés et appareil d'identification de petites cellules WO2014098523A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016048074A1 (fr) * 2014-09-24 2016-03-31 엘지전자 주식회사 Procédé d'émission et de réception de signal de référence dans un système de communications sans fil, et appareil associé
WO2017049646A1 (fr) * 2015-09-25 2017-03-30 华为技术有限公司 Procédé et appareil de mappage de ressource
WO2018059461A1 (fr) * 2016-09-29 2018-04-05 中兴通讯股份有限公司 Procédé et appareil de transmission d'informations
WO2019007159A1 (fr) * 2017-07-07 2019-01-10 华为技术有限公司 Procédé de transmission de données, dispositif d'émission et dispositif de réception
US10447363B2 (en) 2015-12-03 2019-10-15 Huawei Technologies Co., Ltd. Multi-antenna transmission method in co-cell network, and base station

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110176517A1 (en) * 2010-01-20 2011-07-21 Telefonaktiebolaget Lm Ericsson (Publ) Antenna Port Mapping for Demodulation Reference Signals
EP2369776A2 (fr) * 2010-02-11 2011-09-28 Samsung Electronics Co., Ltd. Procédé pour indiquer un port d'antenne DM-RS dans un système de communication sans fil
EP2464076A2 (fr) * 2009-10-16 2012-06-13 LG Electronics Inc. Procédé et appareil d'émission de signal de référence mimo multi-utilisateurs dans un système de communication sans fil pour assistance à un relais
EP2528244A2 (fr) * 2010-01-22 2012-11-28 LG Electronics Inc. Procédé et appareil de fourniture d'informations de commande de liaison descendante dans un système de communication sans fil mimo
US20120300728A1 (en) * 2010-01-19 2012-11-29 Moon Il Lee Method and base station for transmitting downstream link data, and method and user device for receiving downstream link data

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2464076A2 (fr) * 2009-10-16 2012-06-13 LG Electronics Inc. Procédé et appareil d'émission de signal de référence mimo multi-utilisateurs dans un système de communication sans fil pour assistance à un relais
US20120300728A1 (en) * 2010-01-19 2012-11-29 Moon Il Lee Method and base station for transmitting downstream link data, and method and user device for receiving downstream link data
US20110176517A1 (en) * 2010-01-20 2011-07-21 Telefonaktiebolaget Lm Ericsson (Publ) Antenna Port Mapping for Demodulation Reference Signals
EP2528244A2 (fr) * 2010-01-22 2012-11-28 LG Electronics Inc. Procédé et appareil de fourniture d'informations de commande de liaison descendante dans un système de communication sans fil mimo
EP2369776A2 (fr) * 2010-02-11 2011-09-28 Samsung Electronics Co., Ltd. Procédé pour indiquer un port d'antenne DM-RS dans un système de communication sans fil

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016048074A1 (fr) * 2014-09-24 2016-03-31 엘지전자 주식회사 Procédé d'émission et de réception de signal de référence dans un système de communications sans fil, et appareil associé
US10250366B2 (en) 2014-09-24 2019-04-02 Lg Electronics Inc. Method for transmitting and receiving reference signal in wireless communication system and apparatus therefor
WO2017049646A1 (fr) * 2015-09-25 2017-03-30 华为技术有限公司 Procédé et appareil de mappage de ressource
US10447363B2 (en) 2015-12-03 2019-10-15 Huawei Technologies Co., Ltd. Multi-antenna transmission method in co-cell network, and base station
WO2018059461A1 (fr) * 2016-09-29 2018-04-05 中兴通讯股份有限公司 Procédé et appareil de transmission d'informations
WO2019007159A1 (fr) * 2017-07-07 2019-01-10 华为技术有限公司 Procédé de transmission de données, dispositif d'émission et dispositif de réception
US11343056B2 (en) 2017-07-07 2022-05-24 Huawei Technologies Co., Ltd. Data transmission method, sending device, and receiving device

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