BR112017007796B1 - CHANNEL STATUS INFORMATION PROCEDURE FOR ENHANCED COMPONENT CARRIERS - Google Patents

Abstract

CHANNEL STATUS INFORMATION PROCEDURE FOR ENHANCED COMPONENT CARRIERS. Techniques are provided for transmitting reference signals and CSI reports within a wireless communications system using variable-length downlink or uplink transmission time slots (TTIs). CSI reference signals and CSI reports can be transmitted at times that accommodate variable length TTIs. A UE may receive signaling that indicates when a CSI reference signal should be transmitted, and when a CSI report should be transmitted to a base station. CSI reporting may be performed periodically using a physical uplink control channel (PUCCH) on the designed uplink symbols, it may be aperiodic using a shared physical uplink channel (PUSCH), or a combination thereof. A UE may receive signaling indicating the periodic CSI report, the aperiodic CSI report, or both. Such signaling may be received, for example, through radio resource control (RRC) signaling or within a downlink or uplink lease.

Description

Cross References

[0001] The present patent application claims priority to U.S. patent application No. 14/883,487, by Damnjanovic et al., entitled "Channel State Information Procedure for Enhanced Component Carriers," filed on October 14, 2015; and U.S. Provisional Patent Application No. 62/064,953 to Damnjanovic et al., entitled "Channel State Information Procedure for Enhanced Component Carriers," filed October 16, 2014; each of which is assigned to the assignee of this application.

Fundamentals

[0002] The present description, for example, relates to wireless communication systems, and more particularly to the reporting of channel state information in a system employing variable length transmission time slots.

[0003] Wireless communication systems are widely developed to provide various types of communication content such as voice, video, packet data, message sending, broadcasting and so on. These systems may be multiple access systems capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and energy). Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and frequency division multiple access systems. orthogonal frequency control (OFDMA).

[0004] By way of example, a wireless multiple access communication system may include multiple base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UE). A base station can communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).

[0005] These multiple access technologies have been adopted into various telecommunications standards to provide a common protocol that allows different wireless devices to communicate on a city, national, regional, and even global level. An illustrative telecommunications standard is Long Term Evolution (LTE). LTE is designed to improve spectral efficiency, reduce costs, improve services, make use of new spectrum, and better integrate with other open standards. LTE can utilize OFDMA in downlink (DL), single-carrier frequency division multiple access (SC-FDMA) in uplink (UL), and multiple-input multiple-output (MIMO) antenna technology.

[0006] In some cases, one or more parameters used for wireless communications may be determined, at least in part, by the channel conditions associated with a particular communications channel being used by a UE and the base station for communications. wireless. Channel state information can be estimated, in some cases, by a UE receiving a reference signal from a base station. This channel state information (CSI) may be periodically transmitted in a CSI report from the UE to the base station. In situations where the uplink and downlink transmission status of a system may be dynamically modified, CSI reporting at set time intervals may result in conflicts between a scheduled CSI report transmission, which must be transmitted in an uplink transmission. from the UE to the base station, and a dynamically scheduled downlink transmission from the base station to the UE. Therefore, flexible transmissions of CSI reports can improve the efficiency of such systems.

summary

[0007] The described features generally refer to one or more improved systems, methods and/or devices for transmitting reference signals and CSI reports within a wireless communications system. In some examples, base stations and UEs within the wireless communications system may utilize variable-length downlink or uplink transmission time slots (TTIs). CSI reference signals and CSI reports can be transmitted at times that accommodate variable length TTIs. In some examples, a UE may receive signaling that indicates when a CSI reference signal should be transmitted by a base station and when a CSI report should be transmitted to a base station. CSI reporting can be performed periodically using a physical uplink control channel (PUCCH) on designated uplink symbols or can be aperiodic using a physical uplink shared channel (PUSCH). A UE may receive signaling indicating periodic CSI report, aperiodic CSI report, or both. Such signaling may be received, for example, through radio resource control (RRC) signaling or within a downlink or uplink lease.

[0008] According to a first set of illustrative examples, a method for wireless communication is described. In one example, the method may include receiving one or more downlink reference signals in a variable length downlink transmission time slot (TTI), estimating channel state information (CSI) for one or more of the downlink reference signals, and identifying at least a portion of the CSI estimated for transmission in a CSI report on a variable length uplink TTI.

[0009] According to the first set of examples, an apparatus for wireless communication is described. In one embodiment, the apparatus may include means for receiving one or more downlink reference signals on a variable-length downlink TTI, means for estimating the CSI for the one or more downlink reference signals, and means for identifying at least one part of the CSI estimated for transmission in a CSI report on a variable length uplink TTI.

[0010] According to the first set of examples, another apparatus for wireless communication is described. In one embodiment, the apparatus may include a processor; memory in electronic communication with the processor; and instructions stored in memory. Instructions may be executable by the processor to cause the apparatus to: receive one or more downlink reference signals on a variable-length downlink TTI, estimate the CSI for one or more of the downlink reference signals, and identify at least a portion of the CSI estimated for transmission in a CSI report on a variable length uplink TTI.

[0011] According to the first set of examples, a non-transitory computer-readable medium storing computer-executable code for wireless communication is described. In one embodiment, code may be executable to receive one or more downlink reference signals in a variable-length downlink TTI, estimate CSI for one or more downlink reference signals, and identify at least a portion of the estimated CSI for transmission in a CSI report on a variable length uplink TTI.

[0012] In some aspects of the method, apparatus and/or non-transitory computer readable medium of the first set of examples, the variable length downlink TTI may include a variable number of downlink symbols. Receiving downlink reference signals, in some examples, may also include receiving an uplink grant that includes a variable number of uplink symbols and an indication that the CSI report is to be transmitted on a shared physical uplink channel (PUSCH) on one or more of the uplink symbols. In other examples, receipt may also include receipt of signaling that includes a periodicity and an offset to be used to identify when the CSI report should be transmitted. Such signaling may include, for example, radio resource control (RRC) signaling. In some examples, a starting symbol for transmitting the CSI report may be configured as a downlink symbol, and where a subsequent uplink symbol for transmitting the CSI report may be determined as a first available uplink symbol following the starting symbol.

[0013] In some aspects of the method, apparatus and/or non-transitory computer readable medium of the first set of examples, it may be determined that an initial symbol for transmission of the CSI report is configured as a downlink symbol and the transmission of the CSI report can be skipped. In some cases, a subsequent symbol may be identified for transmission of a subsequent CSI report to a reference signal received on one or more subsequent downlink symbols. In some examples, the CSI report may be transmitted on one or more of a physical uplink control channel (PUCCH) or a PUSCH, where transmission on the PUCCH or PUSCH is determined based on one or more of the UE capability, configuration RRC of the UE, and whether the UE receives an Uplink grant, UL, to transmit PUSCH data during the uplink TTI.

[0014] In a second set of illustrative examples, a method for wireless communication is described. In one embodiment, the method may include identifying one or more downlink symbols for CSI transmission during a variable-length downlink TTI comprising a variable number of downlink symbols, signaling transmission indicating one or more identified downlink symbols. , transmitting a CSI reference signal via one or more identified downlink symbols, and receiving a CSI report based in part on the transmitted CSI reference signal.

[0015] According to the second set of examples, an apparatus for wireless communication is described. In one embodiment, the apparatus may include means for identifying one or more downlink symbols for CSI transmission during a variable-length downlink TTI comprising a variable number of downlink symbols, means for transmitting signaling indicating one or more downlink symbols. identified downlink, means for transmitting a CSI reference signal via one or more identified downlink symbols, and means for receiving a CSI report based at least in part on the transmitted CSI reference signal.

[0016] According to the second set of examples, an apparatus for wireless communication is described. In one configuration, the apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. Instructions may be executable by the processor to cause the apparatus to: identify one or more downlink symbols for transmission of the CSI during a variable-length downlink TTI comprising a variable number of downlink symbols, transmit signaling indicating one or more identified downlink symbols, transmit a CSI reference signal via one or more identified downlink symbols, and receive a CSI report based at least in part on the transmitted CSI reference signal.

[0017] According to the second set of examples, a non-transitory computer-readable medium storing computer-executable code for wireless communication is described. In one embodiment, the code may be executable to identify one or more downlink symbols for CSI transmission during a variable-length downlink TTI comprising a variable number of downlink symbols, transmit signaling indicating one or more identified downlink symbols, transmitting a CSI reference signal via one or more identified downlink symbols, and receiving a CSI report based at least in part on the transmitted CSI reference signal.

[0018] In some aspects of the method, apparatus and/or non-transitory computer-readable medium of the second set of examples, one or more identified downlink symbols may include one or more designated symbols. In some examples, the transmitted signaling may also include an indication of one or more symbols designated for at least one UE. The indication of one or more designated symbols may be transmitted, for example, in RRC signaling that includes a periodicity and an offset to be used to identify one or more designated symbols.

[0019] In some aspects of the method, apparatus and/or non-transitory computer readable medium of the second set of examples, it may be determined that an initial uplink symbol for transmission of the CSI report is configured as a downlink symbol, and an variable uplink symbol for transmitting the CSI report can be identified as a first available uplink symbol following the initial uplink symbol. In certain examples, signaling indicating one or more identified downlink symbols may include an uplink grant with an identified number of variable number of uplink symbols for transmission of uplink data, with one or more identified uplink symbols for transmission of the CSI report, and signaling may be transmitted, as part of the uplink grant, indicating one or more downlink symbols and one or more identified uplink symbols.

[0020] In some aspects of the method, apparatus and/or non-transitory computer readable medium of the second set of examples, the CSI report may be received on a physical uplink control channel (PUCCH). In certain examples, the CSI report may be multiplexed with data received on a physical uplink shared channel (PUSCH).

[0021] The above has broadly highlighted the characteristics and technical advantages of the examples in accordance with the description so that the detailed description that follows can be better understood. Additional features and benefits will be described later. The specific design and examples described can be readily used as a basis for modifying or designing other structures to accomplish the same purposes as the present description. Such equivalent constructions do not depart from the scope of the attached claims. The characteristics of the concepts described herein, both in terms of organization and in terms of method of operation, together with the associated advantages will be better understood from the following description when considered in relation to the attached figures. Each of the figures is provided for purposes of illustration and description only, and not as a definition of the limits of the claims.

Brief Description of the Drawings

[0022] A further understanding of the nature and advantages of the present invention can be achieved by reference to the attached drawings. In the attached figures, similar components or features may have the same reference label. Additionally, several components of the same type can be distinguished by following the reference label by a dash and a second label that distinguishes between similar components. If only the first reference label is used in the specification, the description is applicable to any of the similar components having the same first reference label independently of the second reference label.

[0023] Figure 1 illustrates a block diagram of a wireless communication system, in accordance with various aspects of the present description;

[0024] Figure 2 is a diagram illustrating an example of the primary cell and secondary cell frame structures that can be used in a communication system, in accordance with an aspect of the present description;

[0025] Figure 3 is a diagram illustrating an example of dynamic downlink and uplink grants and associated downlink and uplink transmission symbols of a wireless communication system, in accordance with an aspect of the present description;

[0026] Figure 4 is a diagram illustrating another example of dynamic downlink and uplink grants and associated downlink and uplink transmission symbols of a wireless communication system, in accordance with an aspect of the present description;

[0027] Figure 5 is a diagram illustrating an example of downlink symbols designed for transmitting CSI reference signals, uplink symbols designed for transmitting CSI reports, and alternative symbols for such transmissions, in accordance with an aspect of the present description;

[0028] Figure 6 is a diagram illustrating an example of semi-statically or dynamically configured downlink symbols for transmitting CSI reference signals and uplink symbols for transmitting CSI reports, in accordance with an aspect of the present description;

[0029] Figure 7 illustrates a block diagram of a device configured for use in wireless communication, in accordance with various aspects of the present description;

[0030] Figure 8 illustrates a block diagram of a device configured for use in wireless communication, in accordance with various aspects of the present description;

[0031] Figure 9 illustrates a block diagram of a wireless communication system, in accordance with various aspects of the present description;

[0032] Figure 10 illustrates a block diagram of an apparatus for use in wireless communication, in accordance with various aspects of the present description;

[0033] Figure 11 illustrates a block diagram of an apparatus for use in wireless communication, in accordance with various aspects of the present description;

[0034] Figure 12 illustrates a block diagram of a base station (for example, a base station forming part or all of an eNB) for use in wireless communication, in accordance with various aspects of the present description;

[0035] Figure 13 illustrates a block diagram of a multiple input/multiple output communication system, in accordance with various aspects of the present description;

[0036] Figure 14 is a flowchart illustrating an example of a method for wireless communication, in accordance with various aspects of the present description;

[0037] Figure 15 is a flowchart illustrating another example of a method for wireless communication, in accordance with various aspects of the present description;

[0038] Figure 16 is a flowchart illustrating another example of a method for wireless communication, in accordance with various aspects of the present description; It is

[0039] Figure 17 is a flowchart illustrating another example of a method for wireless communication, in accordance with various aspects of the present description.

Detailed Description

[0040] Techniques are described for transmitting channel state information (CSI) reference signals and CSI reports within a system that utilizes variable length transmission time slots (TTIs). CSI reference signals and CSI reports can be transmitted at times that accommodate variable length TTIs. In some examples, a UE may receive signaling that indicates when a CSI reference signal should be transmitted by a base station and when a CSI report should be transmitted to a base station. CSI reporting can be performed periodically using a physical uplink control channel (PUCCH) on designated uplink symbols, or it can be aperiodic using a physical uplink shared channel (PUSCH). A UE may receive signaling indicating periodic CSI reporting, aperiodic CSI reporting, or both. Such signaling may be received, for example, through radio resource control (RRC) signaling or within a downlink or uplink lease.

[0041] In some examples, a UE may receive one or more downlink reference signals on a variable-length downlink TTI, estimate CSI for one or more downlink reference signals, and identify at least a portion of the estimated CSI for transmission in a CSI report on a variable length uplink TTI. For example, a UE may receive a CSI reference signal on a downlink symbol from the base station and may receive an uplink grant having a variable number of uplink symbols and an indication that the CSI report should be transmitted on a PUSCH on one or more of the uplink symbols. In other examples, a UE may receive signaling (e.g., through RRC signaling) that includes a periodicity and an offset to be used for identifying when the CSI report should be transmitted.

[0042] The following description provides examples and does not limit the scope, applicability or examples presented in the claims. Changes can be made to the function and arrangement of discussed elements without departing from the scope of the description. Various examples may omit, replace, or add various procedures or components as appropriate. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined in other examples.

[0043] Figure 1 illustrates an example of a wireless communications system 100 in accordance with various aspects of the description. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access functions. , targeting or mobility. The base stations 104 interface with the core network 130 via return access channel links 132 (e.g., S1, etc.) and may perform radio configuration and programming for communication with the UEs 115, or may operate under the control from a base station controller (not illustrated). In various examples, base stations 105 may communicate, directly or indirectly (e.g., via core network 130), with each other via return access channel links 134 (e.g., X1, etc.), which These can be wired or wireless communication links.

[0044] The base stations 105 may communicate wirelessly with the UEs 115 via one or more base station antennas. Each of the base station locations 105 may provide communications coverage for a respective geographic coverage area 110. In some examples, the base stations 105 may be referred to as a base transceiver station, a radio base station, an access point , a radio transceiver, a Node B, eNodeB (eNB), home Node B, a home eNodeB, or some other suitable terminology. The geographic coverage area 110 for a base station 105 may be divided into sectors creating a portion of the coverage area (not illustrated). The wireless communications system 100 may include base stations 105 of different types (e.g., macro cell and/or small cell base stations). There may be overlapping geographic coverage areas 110 for different technologies.

[0045] In some examples, at least a portion of the wireless communications system 100 may be configured to operate using variable length TTIs, where downlink and uplink TTIs may be dynamically adjusted to provide flexibility to dynamically adapt to operating conditions. particular traffic at a particular time. Certain reference signal transmissions, such as CSI reference signals, may be transmitted at particular times or may be transmitted at varying times. Likewise, certain reports from a UE 115 to the base station 105 may designate certain periodic uplink and downlink resources for such reference signal transmission and reporting and transmission signaling (e.g., RRC signaling, signaling in an information block (SIB), or PDCCH signaling) to the UEs 115 to indicate the designated resources. Additionally or alternatively, a base station 105 may provide aperiodic reference signal transmission and reporting, such as an indication in a downlink grant to a UE 115 that a CSI report should be transmitted using particular uplink resources. A UE 115, in such examples, may receive a CSI reference signal, estimate channel state information based on the CSI reference signal, generate a CSI report, and transmit at least a portion of the CSI report using designated uplink resources. Such variable length TTIs and CSI reporting will be described in greater detail.

[0046] In some examples, the wireless communications system 100 is an LTE/LTE-A network. In LTE/LTE-A networks, the term Evolved Node B (eNB) may be generally used to describe the base stations 105, while the term UE may be generally used to describe the UEs 115. The wireless communications system 100 may be a Heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographic regions. For example, each eNB or base station 105 may provide communications coverage for a macro cell, a small cell, and/or other cell types. The term "cell" is a 3GPP term that may be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g. sector, etc.) of a carrier or station basis, depending on the context.

[0047] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell is a low-power base station, compared to a macro cell, which can operate in the same or other frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell can cover a relatively smaller geographic area and can allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also cover a relatively small geographic area (e.g., a residence) and may provide restricted access by UEs possessing an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users at home and similar). An eNB for a macro cell can be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or several (e.g., two, three, four, and the like) cells (e.g., component carriers).

[0048] The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, base stations can have similar frame timing, and transmissions from different base stations can be nearly aligned in time. For asynchronous operation, base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described here can be used for synchronized or asynchronous operations.

[0049] Communication networks that can accommodate some of the various examples described can be packet-based networks that operate according to a layered protocol stack. At the user plane, communications at the Packet Data Convergence Protocol (PDCP) support or layer can be IP-based. A Radio Link Control (RLC) layer can perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer can perform priority handling and multiplexing of logical channels into transport channels. The MAC layer can also use Hybrid ARQ (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide for the establishment, configuration and maintenance of an RRC connection between a UE 115 and the base stations 105 or core network 130 supporting the radio bearers for the user plan data. At the physical layer (PHY), transport channels can be mapped to Physical channels.

[0050] The UEs 115 are dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also include or may be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device , a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, an apparatus, a user agent, a mobile client, a client or some other suitable terminology. A UE 115 may be a cellular telephone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless telephone, a circuit station wireless location (WLL) or similar. A UE may be capable of communicating with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, and the like.

[0051] The communication links 125 illustrated in the wireless communications system 100 may include uplink transmissions (UL) from a UE 115 to a base station 105, and/or downlink transmissions (DL) from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions. Each communication link 125 may include one or more carriers, where each carrier may be a signal made up of multiple subcarriers (e.g., waveform signals of different frequencies) modulated in accordance with the various radio technologies described above. Each modulated signal can be sent on a different subcarrier and can carry control information (e.g. reference signals, control channels, etc.), overhead information, user data, etc. Communication links 125 may transmit bidirectional communications using FDD (e.g., utilizing paired spectrum resources) or TDD operation (e.g., utilizing unpaired spectrum resources). Frame structures for FDD (e.g. frame structure type 1) and TDD (e.g. frame structure type 2) can be defined.

[0052] In some embodiments of the wireless communications system 100, the base stations 105 and/or UEs 115 may include multiple antennas to employ antenna diversity schemes to improve the quality and reliability of communication between the base stations 105 and the UEs 115. Additionally or alternatively, the base stations 105 and/or UEs 115 may employ multiple input multiple output (MIMO) techniques that can take advantage of multipath environments to transmit multiple spatial layers carrying the same or different coded data.

[0053] The wireless communications system 100 may support operation on multiple cells or carriers, a feature that may be referred to as carrier aggregation (CA) or multiple carrier operation. A carrier may also be referred to as a component carrier (CC), a layer, a channel, etc. The terms "carrier", "component carrier", "cell" and "channel" may be used interchangeably here. A UE 115 may be configured with multiple downlink CCs and one or more uplink CCs for bearer aggregation. Carrier aggregation can be used with both FDD and TDD component carriers.

[0054] As discussed above, several examples provide communications in a wireless communications system, such as the wireless communications system 100 of Figure 1 that utilizes variable TTIs. Figure 2 is a block diagram 200 conceptually illustrating an example of different radio frames and subframes that can be transmitted using different cells of a wireless communication system, such as the wireless communications system 100 of Figure 1. in accordance with aspects of this description. The radio frames of Figure 2 may be transmitted using parts of the wireless communications system 100 described with reference to Figure 1 between one or more base stations 105 and one or more UEs 115, for example. In this example, a legacy primary cell (PCell) transmission 210 may include a TDD frame that includes ten 1 ms subframes that include downlink subframes 225, special subframes 230, and uplink subframes 235. The downlink subframes 225, the Specials 230 and uplink subframes 235 may include a subframe structure defined in accordance with established LTE standards, which may include 14 symbols 266 within each 1 ms subframe. In some examples, downlink subframes 225 may include downlink orthogonal frequency division multiplexing (OFDM) symbols, uplink subframes may include single carrier frequency division multiplexing (SC-FDM) symbols, and special subframes 230 may include both uplink SC-FDM symbols and downlink OFDM symbols.

[0055] In the example of Figure 2, the secondary cell (SCell) transmissions 220 may include low latency or burst mode transmissions that may replace the legacy frame structure with a TDD-based frame structure that allows switching dynamics between downlink and uplink symbols and variable TTI lengths. While the example in Figure 2 illustrates low latency or burst mode transmissions in a SCell, it will be understood that such transmission structures, in addition to various techniques and principles described herein, can be implemented in other transmissions, such as within a or plus burst mode subframes of a legacy LTE frame, and other PCell transmissions, in licensed or unlicensed spectrum, etc. In the example of Figure 2, SCell transmissions 220, which may be referred to as enhanced component carrier transmissions (eCC), may include designated downlink symbols 240, designated uplink symbols 260, and flexible symbols 245 that may be allocated as uplink symbols. or downlink based on particular traffic conditions.

[0056] Designated downlink symbols 240 and designated uplink symbols 260 may be provided to enable various measurements of radio resource management (RRM), synchronization, CSI feedback, random access channel (RACH), and request communications. programming (SR), for example. The designated downlink symbols 240 and designated uplink symbols 260 may be configured by a base station, such as base stations 105 of Figure 1, and may be communicated to one or more UEs, such as UEs 115 of Figure 1, through a or more of RRC signaling, a system information block (SIB), or PDCCH signaling. As mentioned, flexible symbols 245 may be switched to be uplink and downlink symbols, and indication of such configurations may be provided by a base station in an uplink or downlink resource allocation that is provided to a UE. Based on such allocation, the UE may determine that a specified number of symbols 240, 245, 260 may be allocated for communications between the UE and the base station.

[0057] With such dynamic symbol switching, a base station and UE can be freed from looking ahead in terms of a number of uplink or downlink subframes for the entire radio frame, and can instead determine the allocations of particular resources in a dynamic and flexible way. The number of resources allocated to a particular UE may be determined, for example, by an amount of data to be transmitted between the UE and the base station, a latency setting, or quality of service (QoS) threshold associated with the data. In some examples, each of symbols 240, 245, and 260 may have a reduced symbol duration relative to legacy OFDM or SC-FDM symbols (e.g., symbols 266), and in some examples, have a symbol duration of 11.35 µs per symbol, including a useful symbol duration of 8.33 µs and a cyclic prefix duration of 2.03 µs. Symbols 240, 245, and 260 may have increased tone spacing for subcarriers relative to legacy symbols, and, in some examples, have a tone spacing of 120 kHz, and utilize a relatively wide bandwidth (e.g., 80 MHz).

[0058] Such shortened symbol duration and dynamic switching between downlink and uplink communications can allow for reduced acknowledgment/negative acknowledgment (ACK/NACK) round trip time, and can thereby provide transmissions relatively low latency data. In some examples, delay-sensitive data may be transmitted using SCell 220 transmissions, while other data that is not delay-sensitive may be transmitted using PCell 210 transmissions. In some examples, a number of symbols 240, 245, and 260 may be allocated to a first UE for a first time period (T1) 265, and may be allocated to the first UE or one or more other UEs during a second time period (T2) 270 and third time period (T3) 275. The length of such time periods 265, 270, 275 may be determined according to one or more of a variety of factors such as, for example, an amount of data to be transmitted, a QoS associated with the data, a configuration of data delay, the number of other UEs present, or channel conditions, to name just a few.

[0059] Referring now to Figure 3, a block diagram 300 conceptually illustrating an example of enhanced component carrier transmissions (eCC) is discussed. In the example of Figure 3, eCC transmissions 320 may include multiple symbols allocated as uplink or downlink symbols. Such eCC transmissions 320 may be transmitted using different cells of a wireless communication system, such as the wireless communication system 100 of Figure 1, in accordance with aspects of the present description. In some examples, eCC transmissions 320 are transmitted on a SCell as discussed above with respect to Figure 2. In the example of Figure 3, a first time period (T1) 340 may include a nine-symbol downlink grant 330. In this For example, an initial downlink symbol 330 may include control information 335, which may be dynamic, and may indicate resource allocations for an input time period (e.g., T1 340).

[0060] In some examples, control information 335 may include a downlink grant of resources to a UE that includes subsequent symbols 330. In this example, a subsequent transmission of control information 350 may include an uplink grant of eight symbols of uplink symbol 345. A blank symbol 355 may be included between a downlink symbol 330 and an uplink symbol 345 to allow time for switching in a UE. In some examples, beams of symbols 330 and symbols 345 may be allocated to a UE by a base station, with a length of such beams being controlled by dynamic control information 335 and control information 350. A relatively large number of symbols may be allocated to provide improved efficiency in some instances that are somehow less sensitive to delay.

[0061] In other examples, if data transmissions are relatively delay sensitive, dynamic grants to a particular UE may be relatively short in order to provide reduced ACK/NACK round trip times. Figure 4 illustrates an example 400 of relatively short grants. In this example, eCC transmissions 420 may include one- or two-symbol resource allocations. The eCC transmissions 420 of Figure 4 may be transmitted using a wireless communication system, such as the wireless communication system 100 of Figure 1, in accordance with aspects of the present description. In some examples, eCC transmissions 420 are transmitted on a SCell such as that discussed above with respect to Figures 2 and 3. In this example, control information 435 in initial downlink symbol 425 may include a downlink grant of a symbol ( that is, TTI = 1 symbol) and an uplink grant of one symbol (that is, TTI = 1 symbol). The uplink grant, in various examples, may be performed on a minimum of two receiving control information symbols 435 in order to accommodate the blank symbol 430 and allow switching in the UE to transmit the uplink symbol 440. In this example , eCC transmissions 420 include a transmission of second control information 450 which, in this example, is a downlink grant for two symbols (e.g., TTI = 2 symbols), with the third control information 455 providing a subsequent uplink grant which may have a TTI of one or more uplink symbols 440.

[0062] As mentioned above, several examples provide that CSI can be estimated by a UE and transmitted to a base station based on a CSI reference signal that is transmitted from the base station to the UE. Referring now to Figure 5, an example 500 of CSI reference signal transmission and CSI report transmissions within eCC transmissions 520 is discussed. The eCC transmissions 520 of Figure 5 may be transmitted using a wireless communication system, such as the wireless communications system 100 of Figure 1, in accordance with aspects of the present description. In some examples, eCC transmissions 520 are transmitted on a SCell as discussed above with respect to one or more of Figures 2, 3 or 4.

[0063] In the example of Figure 5, CSI reference signals (RS) may be transmitted in designated CSI RS symbols 505. In some examples, designated downlink symbols 505 may be provided to the UEs through, for example, signaling RRC. In some examples, such RRC signaling may indicate that CSI RS will be transmitted during a particular downlink symbol in a downlink grant (e.g., first downlink symbol) referred to as a branch, and also to indicate a periodicity for the CSI RS transmissions. (e.g. every 6 downlink symbols). The periodicity and offset can be defined with respect to a common timing reference that is independent of the timing of the start of a variable-length TTI, and the periodicity and offset can be used to determine which uplink variable-length TTI the CSI report will actually be transmitted. While RRC signaling is used in certain examples, it will be understood that other types of signaling may be used to provide information in designated symbols, such as SIB or PDCCH signaling, for example.

[0064] In response to receiving a CSI RS, a UE may estimate the CSI and generate a CSI report. In some examples, the CSI report may be transmitted to a base station in one or more designated CSI report symbols 510. The designated CSI report symbols 510 may be provided to the UEs in accordance with any of the techniques discussed above. for signaling symbols designated CSI RS 505. If a symbol for periodic CSI reporting is a downlink symbol 530, a UE may skip the report, according to some examples, or may transmit the CSI report at a first transmission opportunity PUCCH following the designated CSI report symbol 510. In the example of Figure 5, a CSI RS may be transmitted on the first downlink symbol 525, which may also include a downlink grant 535 that allocates nine downlink symbols 530 to the UE.

[0065] In this example, the designated symbol of the CSI report 510 is a downlink symbol 530, and thus the UE can transmit the CSI report at the first available PUCCH transmission opportunity on an uplink symbol 545. In the example 5, an uplink grant 540 may be provided to the UE, following which the uplink symbols and the CSI report may be transmitted. In some examples, the CSI report may be transmitted on a PUCCH or PUSCH transmission, as may be defined in RRC signaling. Whether a UE transmits the report on PUCCH or PUSCH can be determined based on one or more factors, such as the amount of data to be transmitted, the availability of a PUCCH or PUSCH transmission, the UE capability (e.g., UE supporting /being configured for simultaneous PUSCH+PUCCH transmission), and existence of PUSCH in that TTI UL (that is, if the UE is programmed for PUSCH transmission), to name just a few examples.

[0066] In other examples, CSI reporting can be performed aperiodically using a PUSCH. Referring now to Figure 6, another example 600 of CSI reference signal transmission and CSI report transmissions within eCC transmissions 620 is discussed. The eCC transmissions 620 of Figure 6 may be transmitted using a wireless communication system, such as the wireless communication system 100 of Figure 1, in accordance with aspects of the present description. In some examples, eCC transmissions 620 are transmitted as an eCC in a SCell as discussed above with respect to one or more of Figures 2, 3, 4 or 5. eCC transmissions 620 may contain downlink symbols 630 and uplink symbols. 645 during which data can be transmitted. A first downlink symbol 625 may contain a downlink grant 635.

[0067] In the example of Figure 6, CSI reference signals may be transmitted on configured CSI RS symbols 605. In some examples, configured CSI RS symbols 605 may be provided to UEs via a downlink grant 635. Additionally, in the 6, CSI reports may be transmitted in configured CSI report symbols 610, which may be provided to UEs in an uplink grant 640. In some examples, a combination of configured symbols 605, 610 and designated symbols 505, 510 can be used for CSI RS and report transmissions. Similarly, as discussed above, in response to receiving a CSI RS, a UE may estimate the CSI and generate a CSI report, which may be transmitted in a configured CSI report symbol 610 which may be included as a or more symbols and uplink 645 allocated to the UE in uplink grant 640.

[0068] Figure 7 illustrates a block diagram 700 of a device 705 for use in wireless communication, in accordance with various aspects of the present description. The device 705 may be an example of one or more aspects of a UE 115 described with reference to FIG. 1. The device 705 may include a receiver module 710, a CSI UE module 715 and/or a transmitter module 720. The device 705 also may be, or include, a processor (not illustrated). Each of these modules can be in communication with the other.

[0069] The components of device 705 may, individually or collectively, be implemented using one or more application-specific integrated circuits (ASICs) adapted to perform some or all of the applicable hardware functions. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits (ICs). In other examples, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Assemblies (FPGAs), and other semi-custom ICs), which may be programmed in any manner known in the art. The functions of each module can also be implemented, in whole or in part, with instructions embodied in a memory, formatted to be executed by one or more general or application-specific processors.

[0070] The receiver module 710 may receive information such as packets, user data and/or control information associated with various information channels (e.g., control channels, data channels, etc.). The receiver module 710 may be configured to receive CSI reference signals and other signals that may indicate a location of a CSI reference signal. The information may be passed to the UE CSI module 715 and to other components of the device 705. The receiver module 710 may illustrate aspects of the transceiver module 935 described with reference to FIG. 9.

[0071] The UE CSI module 715 may be configured to determine CSI report information and symbols assigned or configured for CSI RS and report transmissions, as discussed above with respect to Figures 2 through 6. In some examples, the UE CSI module 715 may illustrate aspects of the processor module 905 described with reference to FIG. 9. The transmitter module 720 may transmit one or more signals received from other components of the device 705. The transmitter module 720 may transmit uplink data and CSI reports, for example. In some examples, the transmitter module 720 may have the same location as the receiver module 710 in a transceiver module. The transmitter module 720 can illustrate aspects of the transceiver module 935 described with reference to Figure 9.

[0072] Figure 8 illustrates a block diagram 800 of a device 705-a for use in wireless communication according to various examples. Device 705-a may be an example of one or more aspects of a UE 115 described with reference to Figure 1. It may also be an example of a device 705 described with reference to Figure 7. Device 705-a may include a module receiver 710-a, a UE CSI module 715-a, and/or a transmitter module 720-a, which may be examples of corresponding modules of device 705. Device 705-a may also include a processor (not illustrated). Each of these components can be in communication with the other. The UE CSI module 715-a may include a reference signal module 805, a CSI estimation module 810, and a CSI reporting module 815. The receiver module 710-a and the transmitter module 720-a may perform the functions of the module receiver 710 and transmitter module 720 of figure 7, respectively.

[0073] The reference signal module 805 can determine a downlink symbol that includes a CSI reference signal, as discussed above with respect to figures 2 through 6. The CSI estimation module 810 can receive information from the signal CSI reference signal and can estimate the CSI based on the reference signal in a manner similar to that discussed above with respect to Figures 2 through 6. The CSI reporting module 815 can transmit a CSI report on an uplink symbol and may determine when such a CSI report should be transmitted, in a manner similar to that discussed above with respect to figures 2 through 6.

[0074] Figure 9 illustrates a system 900 for use in wireless communication according to several examples. The system 900 may include a UE 115-a, which may be an example of the UEs 115 of Figure 1. The UE 115-a may also be an example of one or more aspects of the devices 705 of Figures 7 and 8.

[0075] The UE 115-a may generally include components for two-way voice and data communications including components for transmitting communications and components for receiving communications. The UE 115-a may include antennas 940, a transceiver module 935, a processor module 905, and a memory 915 (including software (SW) 920), each of which may communicate, directly or indirectly, with the other (e.g., via of one or more buses 945). The transceiver module 935 may be configured to communicate bidirectionally, via the antennas 940 and/or one or more wired or wireless links, with one or more networks, as described above. For example, transceiver module 935 may be configured to communicate bidirectionally with base stations 105 with reference to FIG. 1. Transceiver module 935 may include a modem configured to modulate packets and deliver the modulated packets to antennas 940 for transmission. , and to demodulate packets received from the antennas 940. While the UE 115-a may include a single antenna 940, the UE 115-a may have multiple antennas 940 capable of simultaneously transmitting and/or receiving multiple wireless transmissions. The transceiver module 935 may be capable of communicating simultaneously with one or more base stations 105 via multiple component carriers.

[0076] The UE 115-a may include a UE CSI module 715-b, which may perform the functions described above for the UE CSI modules 715 of the device 705 of Figures 7 and 8. The UE 115-a may also include a module reference signal receiving module 925, which can receive CSI or other reference signals that can then be provided to the UE CSI module 715-b. In the example of Figure 9, the UE 115-a also includes the CSI report transmission module 930, which can receive a CSI report from the UE CSI module 715-b and transmit the CSI report on an uplink symbol identified by the UE module. CSI 715-b, in a manner similar to that discussed above with respect to figures 2 to 6.

[0077] Memory 915 may include random access memory (RAM) and read-only memory (ROM). Memory 915 may store computer-readable, computer-executable software/firmware code 920 containing instructions that are configured to, when executed, cause processor module 905 to perform various functions described herein (e.g., determining symbols for CSI reference signals and reports, CSI estimation, report transmission and CSI, etc.). Alternatively, the computer-readable, computer-executable software/firmware code 920 may not be directly executable by the processor module 905, but may be configured to cause a computer (e.g., when compiled and executed) to perform the functions described herein. . The processor module 905 may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), etc.

[0078] Figure 10 illustrates a block diagram 1000 of an apparatus 1005 for use in wireless communication, in accordance with various aspects of the present description. In some examples, the apparatus 1005 may exemplify aspects of one or more of the base stations 105 described with reference to Figure 1. In some examples, the apparatus 1005 may be part of or include an LTE/LTE-A eNB and/or an LTE/LTE-A base station. Apparatus 1005 may also be a processor. Apparatus 1005 may include a receiver module 1010, a base station CSI module 1015, and/or a transmitter module 1020. Each of these modules may be in communication with the other.

[0079] The components of the apparatus 1005 may, individually or collectively, be implemented using one or more ASICs adapted to perform some or all of the applicable hardware functions. Alternatively, the functions may be performed by one or more other processing units (or cores) on one or more integrated circuits. In other examples, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, FPGAs, and other semi-custom ICs), which may be programmed in any manner known in the art. The functions of each component can also be implemented, in whole or in part, with instructions embodied in memory and formatted to be executed by one or more general or application-specific processors.

[0080] In some examples, the receiver module 1010 may include at least one radio frequency (RF) receiver, such as an RF receiver operable to receive CSI reports. The receiver module 1010 may be used to receive various types of data and/or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links of the wireless communications system 100 described with reference to Figure 1. The receiver module 1010 may illustrate aspects of the base station transceiver module 1250 described with reference to Figure 12.

[0081] In some examples, transmitter module 1020 may include at least one RF transmitter, such as at least one RF transmitter operable to transmit CSI reference signals, uplink and downlink grants, and other signaling to UEs. The transmitter module 1020 may be used to transmit various types of data and/or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links of the wireless communications system 100 described with reference to Figure 1. The transmitter module 1020 may illustrate aspects of the base station transceiver module 1250 described with reference to Figure 12.

[0082] In some examples, the base station CSI module 1015 may be configured to determine CSI reporting information, determine symbols designated or configured for CSI RS and report transmissions, transmit control signaling indicating CSI RS symbols, and transmitting the uplink or downlink grants, as discussed above with respect to Figures 2 through 6. In some examples, the base station CSI module 1015 may illustrate aspects of the base station processor module 1210 described with reference to Figure 12. .

[0083] Figure 11 illustrates a block diagram 1100 of an apparatus 1005-a for use in wireless communication, in accordance with various aspects of the present description. In some examples, the apparatus 1005-a may be an example of aspects of one or more of the base stations 105 described with reference to Figure 1 and/or an example of aspects of the apparatus 1005 described with reference to Figure 10. In some examples, The apparatus 1005-a may be part of or include an LTE/LTE-A eNB and/or an LTE/LTE-A base station configured to transmit an eCC. Apparatus 1005-a may also be a processor. The apparatus 1005-a may include a receiver module 1010-a, a base station CSI module 1015-a, and/or a transmitter module 1020-a. Each of these modules can be in communication with another.

[0084] The components of apparatus 1005-a may, individually or collectively, be implemented using one or more ASICs adapted to perform some or all of the applicable hardware functions. Alternatively, the functions may be performed by one or more other processing units (or cores) on one or more integrated circuits. In other examples, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, FPGAs, and other semi-custom ICs), which may be programmed in any manner known in the art. The functions of each component can also be implemented, in whole or in part, with instructions embodied in a memory and formatted to be executed by one or more general or application-specific processors.

[0085] In some examples, the receiver module 1010-a may be an example of one or more aspects of the receiver module 1010 described with reference to Figure 10. In some examples, the receiver module 1010-a may include at least one receiver module. radio frequency (RF), such as at least one RF receiver operable to receive CSI reports and other data transmitted on uplink symbols of an eCC. The receiver module 1010-a may be used to receive various types of data and/or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links. communication of the wireless communications system 100 described with reference to Figure 1.

[0086] In some examples, the transmitter module 1020-a may be an example of one or more aspects of the transmitter module 1020 described with reference to Figure 10. In some examples, the transmitter module 1020-a may include at least one transmitter of RF, such as at least one RF transmitter operable to transmit CSI reference signals, uplink or downlink grants, and control information (e.g., RRC, SIB, or PDCCH signaling, etc.). Transmitter module 1020-a may be used to transmit various types of data and/or control signals (i.e., transmissions) over one or more communication links of a wireless communications system, such as one or more communication links. communication of the wireless communications system 100 described with reference to Figure 1.

[0087] The base station CSI module 1015-a may include a downlink symbol identification module 1105, a reference signal generation module 1110, and a CSI report processing module 1115. The receiver module 1010- a and the transmitter module 1020-a can perform the functions of the receiver module 1010 and the transmitter module 1020 of Figure 10, respectively.

[0088] The downlink symbol identification module 1105 may determine a downlink symbol that should include a CSI reference signal, as discussed above with respect to figures 2 through 6. The reference signal generation module 1110 may generate a CSI reference signal that can be used for CSI estimation, in a manner similar to that discussed above with respect to Figures 2 through 6. The CSI reporting module 815 can receive a CSI report on an uplink symbol and may determine one or more parameters associated with the channel characteristics of the UE, in a manner similar to that discussed above with respect to figures 2 to 6.

[0089] Figure 12 illustrates a block diagram 1200 of a base station 105-a (e.g., a base station forming part or all of an eNB) for use in wireless communication, in accordance with various aspects of the present description. In some examples, the base station 105-a may be an example of aspects of one or more of the base stations 105 described with reference to Figure 1 and/or aspects of one or more of the apparatus 1005 when configured as a base station, as described with reference to Figures 10 and/or 11. Base station 105-a may be configured to implement or facilitate at least some of the base station and/or apparatus features and functions described with reference to Figures 2 to 6.

[0090] Base station 105-a may include a base station processor module 1210, a base station memory module 1220, at least one base station transceiver module (represented by base station transceiver modules 1250), at least one base station antenna (represented by base station antennas 1255), and/or a base station CSI module 1015-b. The base station 105-a may also include one or more of a base station communications module 1230 and/or a network communications module 1240. Each of these modules may be in communication with another, directly or indirectly, through a or more 1235 buses.

[0091] Base station memory module 1220 may include random access memory (RAM) and/or read-only memory (ROM). The base station memory module 1220 may store computer-readable and computer-executable software/firmware code 1225 containing instructions that are configured to, when executed, cause the base station processor module 1210 to perform various functions described herein. with wireless communication (e.g., CSI reference signal downlink symbol location, CSI report symbol location, control signal generation, CSI report reception, determination and signaling of uplink and downlink grants, etc.). Alternatively, the computer-readable and computer-executable software/firmware code 1225 may not be directly executable by the base station processor module 1210, but be configured to cause the base station 105-a to (e.g., compiled and executed) perform many of the functions described here.

[0092] The base station processor module 1210 may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an ASIC, etc. The base station processor module 1210 may process information received through the base station transceiver modules 1250, the base station communications module 1230, and/or the network communications module 1240. The base station processor module 1210 may also process information to be sent to the transceiver modules 1250 for transmission via the antennas 1255, to the base station communications module 1230 for transmission to one or more other base stations 105-b and 105-c, and/or to the base station communications module 1230 for transmission to the network 1240 for transmission to a core network 1245, which may be an example of one or more aspects of the core network 130 described with reference to FIG. 1. The base station processor module 1210 may handle, alone or in relation to the station CSI module base 1015b, various aspects of variable length TTI management and CSI reference signal and report management as discussed here.

[0093] Base station transceiver modules 1250 may include a modem configured to modulate packets and provide the modulated packets to base station antennas 1255 for transmission and to demodulate packets received from base station antennas 1255. base station 1250 may, in some examples, be implemented as one or more base station transmitter modules and one or more base station receiver modules. Base station transceiver modules 1250 may support communications in a first radio frequency spectrum band and/or a second radio frequency spectrum band. The base station transceiver modules 1250 may be configured to communicate bidirectionally, via the antennas 1255, with one or more UEs or apparatus, such as one or more of the UEs 115 described with reference to FIGS. 1 and/or 9. base station 105-a may, for example, include multiple base station antennas 1255 (e.g., an antenna array). The base station 105-a can communicate with the core network 1245 through the network communications module 1240. The base station 105-a can also communicate with other base stations, such as the base stations 105-b and 105-c, using the 1230 base station communications module.

[0094] Base station CSI module 1015-b may be configured to perform and/or control some or all of the features and/or functions described with reference to Figures 2 to 6 relating to variable length TTI and CSI reference signal and reporting to management. The base station CSI module 1015-b, or portions of the base station CSI module 1015-b, may include a processor, and/or some or all of the functions of the base station CSI module 1015-b may be performed by the processor module. of base station 1210 and/or with respect to base station processor module 1210. In some examples, base station CSI module 1015-b may be an example of base station CSI module 1015 and/or 1015-a described with reference to figures 10 and/or 11.

[0095] Figure 13 is a block diagram of a multiple-input/multiple-output (MIMO) communications system 1300 including a base station 105-d and a UE 115-b. The MIMO communications system 1300 may illustrate aspects of the wireless communications system 100 illustrated in FIG. 1. The base station 105-d may be equipped with antennas 1334-a to 1334-x, and the UE 115-b may be equipped with antennas 1352-a to 1352-n. In the MIMO communications system 1300, the base station 105-d may be capable of sending data over multiple communications links at the same time. Each communication link can be called a "layer" and the "classification" of the communication link can indicate the number of layers used for communication. For example, in a 2x2 MIMO communications system where the base station 105-d transmits two "layers", the rating of the communication link between the base station 105-d and the UE 115-b is equal to two.

[0096] At base station 105-d, a transmission processor 1320 may receive data from a data source. The transmission processor 1320 can process the data. The transmission processor 1320 may also generate control symbols and/or reference symbols. A transmit MIMO processor 1330 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, and/or reference symbols, if applicable, and may provide output symbol sequences to the modulators/ 1332-a to 1332-x transmission demodulators. Each modulator/demodulator 1332 may process a respective output symbol sequence (e.g., for OFDM, etc.) to obtain a sequence of output samples. Each modulator/demodulator 1332 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample sequence to obtain a DL signal. In one example, DL signals from modulators/demodulators 1332-a to 1332-x can be transmitted through antennas 1334-a to 1334-x, respectively. The transmit processor 1320, the transmit MIMO processor 1330, transmit modulators/demodulators 1332, or antennas 1334, or some combination of these components, may illustrate aspects of the base station transceiver module 1250 and base station antennas 1255 described with reference to figure 12.

[0097] In the UE 115-b, the UE antennas 1352-a to 1352-n can receive the DL signals from the base station 105-d and can provide the received signals to the demodulators 1354-a to 1354-n, respectively. Each demodulator 1354 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 1354 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 1356 may obtain received symbols from all demodulators 1354-a through 1354-n, perform MIMO detection on the received symbols, if applicable, and output the detected symbols. A receiving processor 1358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data to the UE 115-b for a data output, and providing decoded control information to a processor 1380, or memory 1382 The receiving processor 1358, the MIMO detector 1356, demodulators 1354, or antennas 1352, or some combination of these components, may illustrate aspects of the transceiver module 935 and antennas 940 described with reference to FIG. 9.

[0098] Processor 1380 may, in some cases, execute stored instructions to initiate one or more of a UE CSI 715-c module. The UE CSI module 715-c may be an example of aspects of the UE CSI module 715 described with reference to figures 7, 8 and/or 9.

[0099] In uplink (UL), in the UE 115-b, a transmission processor 1364 can receive and process data from a data source. The transmit processor 1364 may also generate reference symbols for a reference signal. The symbols from the transmit processor 1364 may be pre-coded by a MIMO transmit processor 1366 if applicable, further processed by demodulators 1354-a to 1354-n (e.g., for SC-FDMA, etc.), and transmitted to the station base station 105-d according to the transmission parameters received from the base station 105-d. Transmission processor 1364 or MIMO transmission processor 1366, or both, may illustrate aspects of the transceiver module 935 described with reference to FIG. 9.

[0100] At base station 105-d, UL signals from UE 115-b may be received by antennas 1334, processed by modulators/demodulators 1332, detected by a MIMO detector 1336 if applicable, and further processed by a receive processor 1338 The receiving processor 1338 may provide decoded data to a data output and to the processor 1340 and/or memory 1342. The processor 1340 may, in some cases, execute the stored instructions to initiate one or more of the base station CSI modules. 1015-c. The base station CSI module 1015-c may be an example of aspects of the base station CSI module 1015 described with reference to FIGS. 10, 11 and/or 12. The receiving processor 1338 or MIMO detector 1336, or both, may illustrate aspects of the base station transceiver module 1250 described with reference to Figure 12.

[0101] The components of the UE 115-b may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable hardware functions. Each of the noted modules may be a means for performing one or more functions related to the operation of the MIMO communications system 1300. Similarly, the components of the base station 105-c may, individually or collectively, be implemented with one or more ASICs adapted to perform all or some of the functions applicable in hardware. Each of the noted components may be a means of carrying out one or more functions related to the operation of the MIMO 1300 communications system.

[0102] Figure 14 is a flowchart illustrating an example of a method 1400 for wireless communication, in accordance with various aspects of the present description. For reasons of clarity, method 1400 is described below with reference to aspects of one or more of the UEs 115 described with reference to Figures 1, 9 and/or 13, and/or aspects of one or more of devices 705 described with reference to Figures 7 and/or 8. In some examples, a UE may execute one or more sets of codes to control functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may perform one or more functions described below using special purpose hardware.

[0103] In block 1405, method 1400 may include receiving one or more downlink reference signals on a variable length downlink TTI. The variable length downlink TTI may comprise a variable number of downlink symbols. Operations in block 1405 may be performed using the UE CSI module 715 described with reference to FIGS. 7 to 9 and/or 13. In some examples, operations in block 1405 may be performed using antennas 940 and transceiver module 935 described with reference to figure 9.

[0104] In block 1410, method 1400 may include estimating channel state information (CSI) for one or more of the downlink reference signals. Operations in block 1410 may be performed using the UE CSI module 715 described with reference to FIGS. 7 to 9 and/or 13. In other examples, operations in block 1410 may be performed using memory 915 and the processor module 905 described. with reference to figure 9.

[0105] In block 1415, method 1400 may include identifying at least a portion of the CSI estimated for transmission in a CSI report on a variable length uplink TTI. Operations in block 1415 can be performed using the UE CSI module 715 described with reference to figures 7 to 9 and/or 13. In some examples, operations in block 1415 can be performed using memory 915 and the processor module 905 described with reference to Figure 9.

[0106] In this way, method 1400 can provide wireless communication. It should be noted that method 1400 is only one implementation and that operations of method 1400 may be rearranged or may otherwise be modified so that other implementations are possible.

[0107] Figure 15 is a flowchart illustrating an example of a method 1500 for wireless communication, in accordance with various aspects of the present description. For reasons of clarity, method 1500 is described below with reference to aspects of one or more of the UEs 115 described with reference to Figures 1, 9 and/or 13, and/or aspects of one or more of the devices 705 described with reference to 7 and/or 8. In some examples, a UE may execute one or more sets of codes to control functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may perform one or more of the functions described below using special purpose hardware.

[0108] In block 1505, method 1500 may include receiving signaling that includes a periodicity and an offset to be used for identifying when the CSI report should be transmitted during the variable length uplink TTI. Operations in block 1505 can be performed using the UE CSI module 715 described with reference to figures 7 to 9 and/or 13. In some examples, operations in block 1505 can be performed using antennas 940 and the transceiver module 935 described with reference to Figure 9.

[0109] In block 1510, method 1500 may include determining that a starting symbol for transmitting the CSI report is configured as a downlink symbol. Operations in block 1510 can be performed using the UE CSI module 715 described with reference to figures 7 to 9 and/or 13. In some examples, operations in block 1510 can be performed using memory 915 and the processor module 905 described with reference to Figure 9.

[0110] In block 1515, method 1500 may include identifying a subsequent uplink symbol for transmission of the CSI report as a first available uplink symbol following the initial symbol. Operations in block 1515 can be performed using the UE CSI module 715 described with reference to figures 7 to 9 and/or 13. In some examples, operations in block 1515 can be performed using memory 915 and the processor module 905 described with reference to figure 9.

[0111] In this way, method 1500 can provide wireless communication. It should be noted that method 1500 is only one implementation and that operations of method 1500 may be rearranged or may otherwise be modified so that other implementations are possible.

[0112] Figure 16 is a flowchart illustrating an example of a method 1600 for wireless communication, in accordance with various aspects of the present description. For the sake of clarity, method 1600 is described below with reference to aspects of one or more of the base stations 105 described with reference to Figures 1, 12 and/or 13, and/or aspects of one or more of the apparatus 1005 described with reference to Figures 10 and/or 11. In some examples, a UE may execute one or more sets of codes to control functional elements of the base station to perform the functions described below. Additionally, or alternatively, the base station may perform one or more of the functions described below using special purpose hardware.

[0113] In block 1605, method 1600 may include identifying one or more downlink symbols for CSI transmission during a variable-length downlink TTI comprising a variable number of downlink symbols. Operations in block 1605 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 to 13. In some examples, operations in block 1605 may be performed using the base station memory module 1220 and the base station processor module 1210 as described with reference to Figure 12.

[0114] In block 1610, method 1600 may include transmitting signaling indicating one or more identified downlink symbols. Operations in block 1610 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 through 13. In some examples, operations in block 1610 may be performed using the base station transceiver module. 1250 and the base station antennas 1255 as described with reference to Figure 12.

[0115] In block 1615, method 1600 may include transmitting a CSI reference signal via one or more identified downlink symbols. Operations in block 1615 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 through 13. In some examples, operations in block 1615 may be performed using the base station transceiver module. 1250 and the base station antennas 1255 as described with reference to Figure 12.

[0116] In block 1620, method 1600 may include receiving a CSI report based at least in part on the transmitted CSI reference signal. Operations in block 1620 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 to 13. In some examples, operations in block 1620 may be performed using base station antennas 1255 and the module base station transceiver 1250 as described with reference to Figure 12.

[0117] In this way, method 1600 can provide wireless communication. It should be noted that method 1600 is only one implementation and that operations of method 1600 may be rearranged or may otherwise be modified so that other implementations are possible.

[0018] Figure 7 is a flowchart illustrating an example of a method 1700 for wireless communication, in accordance with various aspects of the present description. For the sake of clarity, method 1700 is described below with reference to aspects of one or more of the base stations 105 described with reference to Figures 1, 12 and/or 13, and/or aspects of one or more of the apparatus 1005 described with reference to Figures 10 and/or 11. In some examples, a UE may execute one or more sets of codes to control functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may perform one or more of the functions described below using special purpose hardware.

[0119] In block 1705, method 1700 may include determining an uplink grant comprising a variable number of uplink symbols for transmitting uplink data. Operations in block 1705 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 through 13. In some examples, operations in block 1705 may be performed using the base station memory module 1220 and the base station processor module 1210 as described with reference to Figure 12.

[0120] In block 1710, method 1700 may include identifying one or more uplink symbols of the uplink grant for transmitting the CSI report. Operations in block 1710 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 to 13. In some examples, operations in block 1710 may be performed using the base station memory module 1220 and the base station processor module 1210 as described with reference to Figure 12.

[0121] In block 1715, method 1700 may include transmitting, as part of the uplink grant, signaling indicating one or more identified downlink symbols and one or more identified uplink symbols. Operations in block 1715 may be performed using the base station CSI module 1015 described with reference to FIGS. 10 through 13. In some examples, operations in block 1715 may be performed using the base station transceiver module. 1250 and the base station antennas 1255 as described with reference to Figure 12.

[0122] In this way, method 1700 can provide wireless communication. It should be noted that method 1700 is only one implementation and that operations of method 1700 may be rearranged or may otherwise be modified so that other implementations are possible.

[0123] In some examples, aspects of two or more of methods 1400, 1500, 1600 or 1700 may be combined. It should be noted that methods 1400, 1500, 1600, 1700 are illustrative implementations only, and that operations of methods 1400-1700 may be rearranged or may otherwise be modified so that other implementations are possible.

[0124] The techniques described here can be used for various wireless communications systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95 and IS-856 standards. IS-2000 Versions 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Broadband CDMA (WCDMA) and other variations of CDMA. A TDMA system can implement a radio technology such as the Global System for Mobile Communications (GSM). An OFDMA system can implement radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (WiFi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization called the "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization called the "3rd Generation Partnership Project 2" (3GPP2). The techniques described here can be used for radio systems and technologies mentioned above in addition to other radio systems and technologies, including cellular communications (e.g., LTE) over unlicensed and/or shared bandwidth. The above description, however, describes an LTE/LTE-A system for example purposes, and the LTE terminology is used in much of the above description, although the techniques are applicable beyond LTE/LTE-A applications.

[0125] The detailed description presented above with respect to the attached drawings describes the examples and does not represent the only examples that can be implemented or that are within the scope of the claims. The terms "example" and "illustrative", when used in this description, mean "serving as an example, case or illustration", and not "preferred" or "advantaged over other examples". The detailed description includes specific details for the purpose of providing an understanding of the techniques described. These techniques, however, can be practiced without these specific details. In some cases, well-known structures and apparatus are illustrated in block diagram form to avoid obscuring the concepts of the examples described.

[0126] Information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic particles or fields, optical particles or fields, or any combination thereof.

[0127] The various illustrative blocks and components described in connection with the description presented here may be implemented or realized with a general purpose processor, a digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other similar configuration.

[0128] The functions described here can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, functions may be stored in or transmitted as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope and spirit of the attached description and claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, wiring, or combinations thereof. Features implementing functions may also be physically located in various positions, including distributed such that parts of the functions are implemented in distinct physical locations. As used herein, including in the claims, the term "and/or", when used in a list of two or more items, means that any one of the listed items may be employed alone, or any combination of two or more of the listed items may be used. be employed. For example, if a composition is described as containing components A, B and/or C, the composition may contain only A; just B; just C; A and B in combination; A and C in combination; B and C in combination; or A, B and C in combination. Furthermore, as used herein, including in the claims, "or" as used in a list of items (e.g., a list of items introduced by a phrase such as "at least one of" or "one or more of") indicates a separate list so that, for example, a list of "at least one of A, B, or C, or any combination thereof" means A or B or C or AB or AC or BC or ABC (that is, A and B and C).

[0129] Computer-readable medium includes both computer storage medium and communication medium including any medium that facilitates the transfer of a computer program from one place to another. A storage medium can be any available medium that can be accessed by a general or special purpose computer. By way of example, and not limitation, the computer-readable medium may comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general or special purpose computer, or a general or special purpose processor. Furthermore, any connection is properly called a computer-readable medium. For example, if the software is transmitted from a network site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared , radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Floppy disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc where floppy disks typically reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included in the scope of computer-readable medium.

[0130] The foregoing description is provided to enable those skilled in the art to create or make use of the description. Various modifications to this description will be readily apparent to those skilled in the art, and the generic principles defined here may be applied to other variations without departing from the scope of the description. Accordingly, the description is not limited to the examples and drawings described here, but the broadest scope consistent with the principles and novelty characteristics described here must be agreed upon.

Claims (12)

1. Method for wireless communication carried out by a user equipment (UE) (115), characterized by the fact that it comprises: receiving (1405) one or more downlink reference signals in a downlink transmission time interval (TTI) variable length, wherein the variable length downlink TTI comprises a variable number of downlink symbols; receiving signaling that includes a periodicity and an offset to be used to identify when a channel state information (CSI) report should be transmitted; estimating (1410) channel state information (CSI) for at least one of the one or more downlink reference signals; and identifying (1415) at least a portion of the CSI estimated for transmission in the CSI report on a variable length uplink TTI; and determining that an initial symbol for transmitting the CSI report is configured as a downlink symbol, wherein the identification further comprises identifying a subsequent uplink symbol for transmitting the CSI report as a first uplink symbol available after the initial symbol. 2. The method of claim 1, wherein receiving (1405) the one or more downlink reference signals further comprises: receiving an uplink grant comprising a variable number of uplink symbols and an indication that the CSI report must be transmitted on a physical uplink shared channel (PUSCH) on one or more of the uplink symbols. 3. Method according to claim 1, characterized by the fact that the signaling comprises radio resource control (RRC) signaling. 4. The method of claim 1, further comprising: skipping transmission of the CSI report. 5. The method of claim 4, wherein the identification (1415) further comprises identifying a subsequent symbol for transmission of a subsequent CSI report for a reference signal received in one or more subsequent downlink symbols. 6. The method of claim 1, further comprising: transmitting the CSI report on one or more of a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH), where transmission on the PUCCH or PUSCH is determined based on at least one of a user equipment (UE) capability, a radio resource control (RRC) configuration of the UE, or whether the UE receives an uplink lease ( UL) to transmit the PUSCH data during the variable length uplink TTI, or a combination thereof. 7. Apparatus for wireless communication, characterized in that it comprises: means for receiving (710) one or more downlink reference signals in a downlink transmission time interval (TTI) of variable length, wherein the TTI of variable length downlink comprises a variable number of downlink symbols; means for receiving signaling that includes a periodicity and an offset to be used to identify when a channel state information (CSI) report should be transmitted; means for estimating (715) channel state information (CSI) for at least one of the one or more downlink reference signals; means for identifying (715) at least a portion of the CSI estimated for transmission in the CSI report on a variable length uplink TTI; and means for determining that an initial symbol for transmission of the CSI report is configured as a downlink symbol, wherein the means for identification is operable to identify a subsequent uplink symbol for transmission of the CSI report as a first available uplink symbol after the initial symbol. 8. The apparatus of claim 7, wherein the means for receiving (710) the one or more downlink reference signals is operable to receive an uplink grant comprising a variable number of uplink symbols and a indication that the CSI report is to be transmitted on a physical uplink shared channel (PUSCH) on one or more of the uplink symbols. 9. The apparatus of claim 7, wherein the signaling comprises radio resource control (RRC) signaling. 10. The apparatus of claim 7, further comprising: means for skipping transmission of the CSI report. 11. The apparatus of claim 7, further comprising: means for transmitting the CSI report on one or more of a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH ), where transmission on the PUCCH or PUSCH is determined based on at least one of a user equipment (UE) capability, a radio resource control (RRC) configuration of the UE, or whether the UE receives a grant of uplink (UL) to transmit PUSCH data during variable length uplink TTI, or a combination thereof. 12. Computer-readable memory, characterized by the fact that it comprises instructions stored therein which, when executed by a computer, perform the method as defined in any one of claims 1 to 6.