Patent Description:
Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency divisional multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, a national, a regional, and even a global level. An example of a telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, using new spectrum, and integrating with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology.

<CIT> relates to an apparatus and method for setting uplink transmission power in a wireless communication system.

<CIT> relates to a user terminal, a radio base station and a radio communication method in a next-generation mobile communication system.

There still exists a need for improving uplink performance.

A solution is provided according to the subject matter of the independent claims.

Wording such as "may" and "for example" used in the description in conjunction with features of the independent claims should not be interpreted to mean that those features are merely optional.

The detailed description includes specific details for providing a thorough understanding of the various concepts.

The techniques described herein may be used for one or more of various wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, or other types of networks. A CDMA network may implement a radio access technology (RAT) such as universal terrestrial radio access (UTRA), CDMA2000, and/or the like. UTRA may include wideband CDMA (WCDMA) and/or other variants of CDMA. CDMA2000 may include Interim Standard (IS)-<NUM>, IS-<NUM> and IS-<NUM> standards. IS-<NUM> may also be referred to as 1x radio transmission technology (1xRTT), CDMA2000 1X, and/or the like. A TDMA network may implement a RAT such as global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), or GSM/EDGE radio access network (GERAN). An OFDMA network may implement a RAT such as evolved UTRA (E-UTRA), ultra mobile broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM, and/or the like. UTRA and E-UTRA may be part of the universal mobile telecommunication system (UMTS). 3GPP long-term evolution (LTE) and LTE-Advanced (LTE-A) are example releases of UMTS that use E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. The techniques described herein may be used for the wireless networks and RATs mentioned above as well as other wireless networks and RATs.

<FIG> is a diagram illustrating an example deployment <NUM> in which multiple wireless networks have overlapping coverage, in accordance with various aspects of the present disclosure. However, wireless networks may not have overlapping coverage in aspects. As shown, example deployment <NUM> may include an evolved universal terrestrial radio access network (E-UTRAN) <NUM>, which may include one or more evolved Node Bs (eNBs) <NUM>, and which may communicate with other devices or networks via a serving gateway (SGW) <NUM> and/or a mobility management entity (MME) <NUM>. As further shown, example deployment <NUM> may include a radio access network (RAN) <NUM>, which may include one or more base stations <NUM>, and which may communicate with other devices or networks via a mobile switching center (MSC) <NUM> and/or an inter-working function (IWF) <NUM>. As further shown, example deployment <NUM> may include one or more user equipment (UEs) <NUM> capable of communicating via E-UTRAN <NUM> and/or RAN <NUM>.

E-UTRAN <NUM> may support, for example, LTE or another type of RAT. E-UTRAN <NUM> may include eNBs <NUM> and other network entities that can support wireless communication for UEs <NUM>. Each eNB <NUM> may provide communication coverage for a particular geographic area. The term "cell" may refer to a coverage area of eNB <NUM> and/or an eNB subsystem serving the coverage area on a specific frequency channel.

SGW <NUM> may communicate with E-UTRAN <NUM> and may perform various functions, such as packet routing and forwarding, mobility anchoring, packet buffering, initiation of network-triggered services, and/or the like. MME <NUM> may communicate with E-UTRAN <NUM> and SGW <NUM> and may perform various functions, such as mobility management, bearer management, distribution of paging messages, security control, authentication, gateway selection, and/or the like, for UEs <NUM> located within a geographic region served by MME <NUM> of E-UTRAN <NUM>. The network entities in LTE are described in 3GPP Technical Specification (TS) <NUM>, entitled "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description," which is publicly available.

RAN <NUM> may support, for example, GSM or another type of RAT. RAN <NUM> may include base stations <NUM> and other network entities that can support wireless communication for UEs <NUM>. MSC <NUM> may communicate with RAN <NUM> and may perform various functions, such as voice services, routing for circuit-switched calls, and mobility management for UEs <NUM> located within a geographic region served by MSC <NUM> of RAN <NUM>. In some aspects, IWF <NUM> may facilitate communication between MME <NUM> and MSC <NUM> (e.g., when E-UTRAN <NUM> and RAN <NUM> use different RATs). Additionally, or alternatively, MME <NUM> may communicate directly with an MME that interfaces with RAN <NUM>, for example, without IWF <NUM> (e.g., when E-UTRAN <NUM> and RAN <NUM> use a same RAT). In some aspects, E-UTRAN <NUM> and RAN <NUM> may use the same frequency and/or the same RAT to communicate with UE <NUM>. In some aspects, E-UTRAN <NUM> and RAN <NUM> may use different frequencies and/or RATs to communicate with UEs <NUM>. As used herein, the term base station is not tied to any particular RAT, and may refer to an eNB (e.g., of an LTE network) or another type of base station associated with a different type of RAT.

A RAT may also be referred to as a radio technology, an air interface, etc. A frequency or frequency ranges may also be referred to as a carrier, a frequency channel, and/or the like. Each frequency or frequency range may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs.

UE <NUM> may be stationary or mobile and may also be referred to as a mobile station, a terminal, an access terminal, a wireless communication device, a subscriber unit, a station, and/or the like. UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, etc..

Upon power up, UE <NUM> may search for wireless networks from which UE <NUM> can receive communication services. If UE <NUM> detects more than one wireless network, then a wireless network with the highest priority may be selected to serve UE <NUM> and may be referred to as the serving network. UE <NUM> may perform registration with the serving network, if necessary. UE <NUM> may then operate in a connected mode to actively communicate with the serving network. Alternatively, UE <NUM> may operate in an idle mode and camp on the serving network if active communication is not required by UE <NUM>.

UE <NUM> may operate in the idle mode as follows. UE <NUM> may identify all frequencies/RATs on which it is able to find a "suitable" cell in a normal scenario or an "acceptable" cell in an emergency scenario, where "suitable" and "acceptable" are specified in the LTE standards. UE <NUM> may then camp on the frequency/RAT with the highest priority among all identified frequencies/RATs. UE <NUM> may remain camped on this frequency/RAT until either (i) the frequency/RAT is no longer available at a predetermined threshold or (ii) another frequency/RAT with a higher priority reaches this threshold. In some aspects, UE <NUM> may receive a neighbor list when operating in the idle mode, such as a neighbor list included in a system information block type <NUM> (SIB <NUM>) provided by an eNB of a RAT on which UE <NUM> is camped. Additionally, or alternatively, UE <NUM> may generate a neighbor list. A neighbor list may include information identifying one or more frequencies, at which one or more RATs may be accessed, priority information associated with the one or more RATs, and/or the like.

<FIG> is a diagram illustrating an example access network <NUM> in an LTE network architecture, in accordance with various aspects of the present disclosure. As shown, access network <NUM> may include one or more eNBs <NUM> (sometimes referred to as "base stations" herein) that serve a corresponding set of cellular regions (cells) <NUM>, one or more low power eNBs <NUM> that serve a corresponding set of cells <NUM>, and a set of UEs <NUM>.

Each eNB <NUM> may be assigned to a respective cell <NUM> and may be configured to provide an access point to a RAN. For example, eNB <NUM>, <NUM> may provide an access point for UE <NUM>, <NUM> to E-UTRAN <NUM> (e.g., eNB <NUM> may correspond to eNB <NUM>, shown in <FIG>) or may provide an access point for UE <NUM>, <NUM> to RAN <NUM> (e.g., eNB <NUM> may correspond to base station <NUM>, shown in <FIG>). In some cases, the terms base station and eNB may be used interchangeably, and a base station, as used herein, is not tied to any particular RAT. UE <NUM>, <NUM> may correspond to UE <NUM>, shown in <FIG>. <FIG> does not illustrate a centralized controller for example access network <NUM>, but access network <NUM> may use a centralized controller in some aspects. The eNBs <NUM> may perform radio related functions including radio bearer control, admission control, mobility control, scheduling, security, and network connectivity (e.g., to SGW <NUM>).

As shown in <FIG>, one or more low power eNBs <NUM> may serve respective cells <NUM>, which may overlap with one or more cells <NUM> served by eNBs <NUM>. The eNBs <NUM> may correspond to eNB <NUM> associated with E-UTRAN <NUM> and/or base station <NUM> associated with RAN <NUM>, shown in <FIG>. A low power eNB <NUM> may be referred to as a remote radio head (RRH). The low power eNB <NUM> may include a femto cell eNB (e.g., home eNB (HeNB)), a pico cell eNB, a micro cell eNB, and/or the like.

A modulation and multiple access scheme employed by access network <NUM> may vary depending on the particular telecommunications standard being deployed. In LTE applications, orthogonal frequency division multiplexing (OFDM) is used on the downlink (DL) and SC-FDMA is used on the uplink (UL) to support both frequency division duplexing (FDD) and time division duplexing (TDD). The various concepts presented herein are well suited for LTE applications. However, these concepts may be readily extended to other telecommunication standards employing other modulation and multiple access techniques. By way of example, these concepts may be extended to Evolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB). EV-DO and UMB are air interface standards promulgated by the 3rd Generation Partnership Project <NUM> (3GPP2) as part of the CDMA2000 family of standards and employs CDMA to provide broadband Internet access to mobile stations. As another example, these concepts may also be extended to UTRA employing WCDMA and other variants of CDMA (e.g., such as TD-SCDMA, GSM employing TDMA, E-UTRA, and/or the like), UMB, IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM employing OFDMA, and/or the like. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from the 3GPP organization. CDMA2000 and UMB are described in documents from the 3GPP2 organization. The actual wireless communication standard and the multiple access technology employed will depend on the specific application and the overall design constraints imposed on the system.

The eNBs <NUM> may have multiple antennas supporting MIMO technology. The use of MIMO technology enables eNBs <NUM> to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data simultaneously on the same frequency. The data streams may be transmitted to a single UE <NUM>, <NUM> to increase the data rate or to multiple UEs <NUM> to increase the overall system capacity. This may be achieved by spatially precoding each data stream (e.g., applying a scaling of an amplitude and a phase) and then transmitting each spatially precoded stream through multiple transmit antennas on the DL. The spatially precoded data streams arrive at the UE(s) <NUM> with different spatial signatures, which enables each of the UE(s) <NUM> to recover the one or more data streams destined for that UE <NUM>, <NUM>. On the UL, each UE <NUM>, <NUM> transmits a spatially precoded data stream, which enables eNBs <NUM> to identify the source of each spatially precoded data stream.

Spatial multiplexing is generally used when channel conditions are good. When channel conditions are less favorable, beamforming may be used to focus the transmission energy in one or more directions. This may be achieved by spatially precoding the data for transmission through multiple antennas. To achieve good coverage at the edges of the cell, a single stream beamforming transmission may be used in combination with transmit diversity.

In the detailed description that follows, various aspects of an access network will be described with reference to a MIMO system supporting OFDM on the DL. OFDM is a spread-spectrum technique that modulates data over a number of subcarriers within an OFDM symbol. The subcarriers are spaced apart at precise frequencies. The spacing provides "orthogonality" that enables a receiver to recover the data from the subcarriers. In the time domain, a guard interval (e.g., cyclic prefix) may be added to each OFDM symbol to combat inter-OFDM-symbol interference. The UL may use SC-FDMA in the form of a DFT-spread OFDM signal to compensate for high peak-to-average power ratio (PAPR).

The number and arrangement of devices and cells shown in <FIG> are provided as an example. In practice, there may be additional devices and/or cells, fewer devices and/or cells, different devices and/or cells, or differently arranged devices and/or cells than those shown in <FIG>.

<FIG> is a diagram illustrating an example <NUM> of a downlink (DL) frame structure in LTE, in accordance with various aspects of the present disclosure. A frame (e.g., of <NUM>) may be divided into <NUM> equally sized sub-frames with indices of <NUM> through <NUM>. Each sub-frame may include two consecutive time slots. A resource grid may be used to represent two time slots, each time slot including a resource block (RB). The resource grid is divided into multiple resource elements. In LTE, a resource block includes <NUM> consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each OFDM symbol, <NUM> consecutive OFDM symbols in the time domain, or <NUM> resource elements. For an extended cyclic prefix, a resource block includes <NUM> consecutive OFDM symbols in the time domain and has <NUM> resource elements. Some of the resource elements, as indicated as R <NUM> and R <NUM>, include DL reference signals (DL-RS). The DL-RS include Cell-specific RS (CRS) (also sometimes called common RS) <NUM> and UE-specific RS (UE-RS) <NUM>. UE-RS <NUM> are transmitted only on the resource blocks upon which the corresponding physical DL shared channel (PDSCH) is mapped. The number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks that a UE receives and the higher the modulation scheme, the higher the data rate for the UE.

In LTE, an eNB may send a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) for each cell in the eNB. The primary and secondary synchronization signals may be sent in symbol periods <NUM> and <NUM>, respectively, in each of subframes <NUM> and <NUM> of each radio frame with the normal cyclic prefix (CP). The synchronization signals may be used by UEs for cell detection and acquisition. The eNB may send a Physical Broadcast Channel (PBCH) in symbol periods <NUM> to <NUM> in slot <NUM> of subframe <NUM>. The PBCH may carry certain system information.

The eNB may send a Physical Control Format Indicator Channel (PCFICH) in the first symbol period of each subframe. The PCFICH may convey the number of symbol periods (M) used for control channels, where M may be equal to <NUM>, <NUM> or <NUM> and may change from subframe to subframe. M may also be equal to <NUM> for a small system bandwidth, e.g., with less than <NUM> resource blocks. The eNB may send a Physical hybrid automatic repeat request (HARQ) Indicator Channel (PHICH) and a Physical Downlink Control Channel (PDCCH) in the first M symbol periods of each subframe. The PHICH may carry information to support hybrid automatic repeat request (HARQ). The PDCCH may carry information on resource allocation for UEs and control information for downlink channels. The eNB may send a Physical Downlink Shared Channel (PDSCH) in the remaining symbol periods of each subframe. The PDSCH may carry data for UEs scheduled for data transmission on the downlink.

The eNB may send the PSS, SSS, and PBCH in the center <NUM> of the system bandwidth used by the eNB. The eNB may send the PCFICH and PHICH across the entire system bandwidth in each symbol period in which these channels are sent. The eNB may send the PDCCH to groups of UEs in certain portions of the system bandwidth. The eNB may send the PDSCH to specific UEs in specific portions of the system bandwidth. The eNB may send the PSS, SSS, PBCH, PCFICH, and PHICH in a broadcast manner to all UEs, may send the PDCCH in a unicast manner to specific UEs, and may also send the PDSCH in a unicast manner to specific UEs.

A number of resource elements may be available in each symbol period. Each resource element (RE) may cover one subcarrier in one symbol period and may be used to send one modulation symbol, which may be a real or complex value. Resource elements not used for a reference signal in each symbol period may be arranged into resource element groups (REGs). Each REG may include four resource elements in one symbol period. The PCFICH may occupy four REGs, which may be spaced approximately equally across frequency, in symbol period <NUM>. The PHICH may occupy three REGs, which may be spread across frequency, in one or more configurable symbol periods. For example, the three REGs for the PHICH may all belong in symbol period <NUM> or may be spread in symbol periods <NUM>, <NUM>, and <NUM>. The PDCCH may occupy <NUM>, <NUM>, <NUM>, or <NUM> REGs, which may be selected from the available REGs, in the first M symbol periods, for example. Only certain combinations of REGs may be allowed for the PDCCH.

A UE may know the specific REGs used for the PHICH and the PCFICH. The UE may search different combinations of REGs for the PDCCH. The number of combinations to search is typically less than the number of allowed combinations for the PDCCH. An eNB may send the PDCCH to the UE in any of the combinations that the UE will search.

Other examples are possible and may differ from what was described above in connection with <FIG>.

<FIG> is a diagram illustrating an example <NUM> of an uplink (UL) frame structure in LTE, in accordance with various aspects of the present disclosure. The available resource blocks for the UL may be partitioned into a data section and a control section. The control section may be formed at the two edges of the system bandwidth and may have a configurable size. The resource blocks in the control section may be assigned to UEs for transmission of control information. The data section may include all resource blocks not included in the control section. The UL frame structure results in the data section including contiguous subcarriers, which may allow a single UE to be assigned all of the contiguous subcarriers in the data section.

A UE may be assigned resource blocks 410a, 410b in the control section to transmit control information to an eNB. The UE may also be assigned resource blocks 420a, 420b in the data section to transmit data to the eNB. The UE may transmit control information in a physical UL control channel (PUCCH) on the assigned resource blocks in the control section. The UE may transmit only data or both data and control information in a physical UL shared channel (PUSCH) on the assigned resource blocks in the data section. A UL transmission may span both slots of a subframe and may hop across frequencies.

A set of resource blocks may be used to perform initial system access and achieve UL synchronization in a physical random access channel (PRACH) <NUM>. The PRACH <NUM> carries a random sequence and cannot carry any UL data/signaling. Each random access preamble occupies a bandwidth corresponding to six consecutive resource blocks. The starting frequency is specified by the network. That is, the transmission of the random access preamble is restricted to certain time and frequency resources. There is no frequency hopping for the PRACH. The PRACH attempt is carried in a single subframe (e.g., of <NUM>) or in a sequence of few contiguous subframes and a UE can make only a single PRACH attempt per frame (e.g., of <NUM>).

<FIG> is a diagram illustrating an example <NUM> of a radio protocol architecture for a user plane and a control plane in LTE, in accordance with various aspects of the present disclosure. The radio protocol architecture for the UE and the eNB is shown with three layers: Layer <NUM>, Layer <NUM>, and Layer <NUM>. Layer <NUM> (L1 layer) is the lowest layer and implements various physical layer signal processing functions. The L1 layer will be referred to herein as the physical layer <NUM>. Layer <NUM> (L2 layer) <NUM> is above the physical layer <NUM> and is responsible for the link between the UE and eNB over the physical layer <NUM>.

In the user plane, the L2 layer <NUM> includes, for example, a media access control (MAC) sublayer <NUM>, a radio link control (RLC) sublayer <NUM>, and a packet data convergence protocol (PDCP) sublayer <NUM>, which are terminated at the eNB on the network side. Although not shown, the UE may have several upper layers above the L2 layer <NUM> including a network layer (e.g., IP layer) that is terminated at a packet data network (PDN) gateway on the network side, and an application layer that is terminated at the other end of the connection (e.g., far end UE, server, etc.).

The PDCP sublayer <NUM> provides retransmission of lost data in handover. The PDCP sublayer <NUM> also provides header compression for upper layer data packets to reduce radio transmission overhead, security by ciphering the data packets, and handover support for UEs between eNBs. The RLC sublayer <NUM> provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to hybrid automatic repeat request (HARQ). The MAC sublayer <NUM> provides multiplexing between logical and transport channels. The MAC sublayer <NUM> is also responsible for allocating the various radio resources (e.g., resource blocks) in one cell among the UEs. The MAC sublayer <NUM> is also responsible for HARQ operations.

In the control plane, the radio protocol architecture for the UE and eNB is substantially the same for the physical layer <NUM> and the L2 layer <NUM> with the exception that there is no header compression function for the control plane. The control plane also includes a radio resource control (RRC) sublayer <NUM> in Layer <NUM> (L3 layer). The RRC sublayer <NUM> is responsible for obtaining radio resources (i.e., radio bearers) and for configuring the lower layers using RRC signaling between the eNB and the UE.

<FIG> is a diagram illustrating example components <NUM> of eNB <NUM>, <NUM>, <NUM> and UE <NUM>, <NUM> in an access network, in accordance with various aspects of the present disclosure. As shown in <FIG>, eNB <NUM>, <NUM>, <NUM> may include a controller/processor <NUM>, a TX processor <NUM>, a channel estimator <NUM>, an antenna <NUM>, a transmitter 625TX, a receiver 625RX, an RX processor <NUM>, and a memory <NUM>. As further shown in <FIG>, UE <NUM>, <NUM> may include a receiver RX, for example, of a transceiver TX/RX <NUM>, a transmitter TX, for example, of a transceiver TX/RX <NUM>, an antenna <NUM>, an RX processor <NUM>, a channel estimator <NUM>, a controller/processor <NUM>, a memory <NUM>, a data sink <NUM>, a data source <NUM>, and a TX processor <NUM>.

In the DL, upper layer packets from the core network are provided to controller/processor <NUM>. The controller/processor <NUM> implements the functionality of the L2 layer. In the DL, the controller/processor <NUM> provides header compression, ciphering, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocations to the UE <NUM>, <NUM> based, at least in part, on various priority metrics. The controller/processor <NUM> is also responsible for HARQ operations, retransmission of lost packets, and signaling to the UE <NUM>, <NUM>.

The TX processor <NUM> implements various signal processing functions for the L1 layer (e.g., physical layer). The signal processing functions includes coding and interleaving to facilitate forward error correction (FEC) at the UE <NUM>, <NUM> and mapping to signal constellations based, at least in part, on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols are then split into parallel streams. Each stream is then mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE <NUM>, <NUM>. Each spatial stream is then provided to a different antenna <NUM> via a separate transmitter TX, for example, of transceiver TX/RX <NUM>. Each such transmitter TX modulates a radio frequency (RF) carrier with a respective spatial stream for transmission.

At the UE <NUM>, <NUM>, each receiver RX, for example, of a transceiver TX/RX <NUM> receives a signal through its respective antenna <NUM>. Each such receiver RX recovers information modulated onto an RF carrier and provides the information to the receiver (RX) processor <NUM>. The RX processor <NUM> implements various signal processing functions of the L1 layer. The RX processor <NUM> performs spatial processing on the information to recover any spatial streams destined for the UE <NUM>, <NUM>. If multiple spatial streams are destined for the UE <NUM>, <NUM>, the spatial streams may be combined by the RX processor <NUM> into a single OFDM symbol stream. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the eNB <NUM>, <NUM>, <NUM>. These soft decisions may be based, at least in part, on channel estimates computed by the channel estimator <NUM>. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNB <NUM>, <NUM>, <NUM> on the physical channel. The data and control signals are then provided to the controller/processor <NUM>.

The controller/processor <NUM> implements the L2 layer. The memory <NUM> may include a non-transitory computer-readable medium. In the UL, the controller/processor <NUM> provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover upper layer packets from the core network. The upper layer packets are then provided to a data sink <NUM>, which represents all the protocol layers above the L2 layer. Various control signals may also be provided to the data sink <NUM> for L3 processing. The controller/processor <NUM> is also responsible for error detection using an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support HARQ operations.

In the UL, a data source <NUM> is used to provide upper layer packets to the controller/processor <NUM>. The data source <NUM> represents all protocol layers above the L2 layer. Similar to the functionality described in connection with the DL transmission by the eNB <NUM>, <NUM>, <NUM>, the controller/processor <NUM> implements the L2 layer for the user plane and the control plane by providing header compression, ciphering, packet segmentation and reordering, and multiplexing between logical and transport channels based, at least in part, on radio resource allocations by the eNB <NUM>, <NUM>, <NUM>. The controller/processor <NUM> is also responsible for HARQ operations, retransmission of lost packets, and signaling to the eNB <NUM>, <NUM>, <NUM>.

Channel estimates derived by a channel estimator <NUM> from a reference signal or feedback transmitted by the eNB <NUM>, <NUM>, <NUM> may be used by the TX processor <NUM> to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor <NUM> are provided to different antenna <NUM> via separate transmitters TX, for example, of transceivers TX/RX <NUM>. Each transmitter TX, for example, of transceiver TX/RX <NUM> modulates an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the eNB <NUM>, <NUM>, <NUM> in a manner similar to that described in connection with the receiver function at the UE <NUM>, <NUM>. Each receiver RX, for example, of transceiver TX/RX <NUM> receives a signal through its respective antenna <NUM>. Each receiver RX, for example, of transceiver TX/RX <NUM> recovers information modulated onto an RF carrier and provides the information to a RX processor <NUM>. The RX processor <NUM> may implement the L1 layer.

The controller/processor <NUM> implements the L2 layer. The controller/processor <NUM> can be associated with a memory <NUM> that stores program code and data. In the UL, the control/processor <NUM> provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover upper layer packets from the UE <NUM>, <NUM>. Upper layer packets from the controller/processor <NUM> may be provided to the core network.

One or more components of UE <NUM>, <NUM> may be configured to perform adjusting transmit power for power-limited uplink carrier aggregation scenarios, as described in more detail elsewhere herein. For example, the controller/processor <NUM> and/or other processors and modules of UE <NUM>, <NUM> may perform or direct operations of, for example, example process <NUM> of <FIG>, and/or other processes as described herein. In some aspects, one or more of the components shown in <FIG> may be employed to perform example process <NUM>, and/or other processes for the techniques described herein.

In some aspects, UE <NUM>, <NUM> may include means for decreasing a first value of a transmission power of a first component carrier relative to a second value of a transmission power of a second component carrier based at least in part on the second component carrier carrying control information; means for increasing the transmission power of the second component carrier to a third value based at least in part on a second maximum power reduction value identified for single carrier; means for identifying the first maximum power reduction value for carrier aggregation; means for identifying the second maximum power reduction value for single carrier after decreasing the first value of the transmission power of the first component carrier; means for dropping the first component carrier due to priority being given to the second component carrier; means for decreasing the first value of the transmission power of the first component carrier to substantially zero, and/or the like. In some aspects, such means may include one or more components of UE <NUM>, <NUM> described in connection with <FIG>.

<FIG> are illustrations of examples <NUM> of carrier aggregation types, in accordance with various aspects of the present disclosure.

In some aspects, UE <NUM>, <NUM> may use spectrum of up to <NUM> bandwidths allocated in a carrier aggregation of up to a total of <NUM> (e.g., <NUM> component carriers) used for transmission and reception. For an LTE-Advanced enabled wireless communication system, two types of carrier aggregation (CA) methods may be used, contiguous CA and non-contiguous CA, which are illustrated in <FIG>, respectively. Contiguous CA occurs when multiple available component carriers are adjacent to each other (e.g., as illustrated in <FIG>). On the other hand, non-contiguous CA occurs when multiple non-adjacent available component carriers are separated along the frequency band (e.g., as illustrated in <FIG>) and/or are included in different frequency bands.

Both non-contiguous and contiguous CA may aggregate multiple component carriers to serve a single unit of LTE-Advanced UEs <NUM>, <NUM>. In various examples, UE <NUM>, <NUM> operating in a multicarrier system (e.g., also referred to as carrier aggregation) is configured to aggregate certain functions of multiple carriers, such as control and feedback functions, on the same carrier, which may be referred to as a primary carrier. The remaining carriers that depend on the primary carrier for support may be referred to as secondary carriers. For example, UE <NUM>, <NUM> may aggregate control functions such as those provided by the optional dedicated channel (DCH), the nonscheduled grants, a physical uplink control channel (PUCCH), and/or a physical downlink control channel (PDCCH).

Other examples are possible and may differ from what was described in connection with <FIG>.

A UE (e.g., UE <NUM>, <NUM>) may configure a transmission power of an uplink signal based at least in part on feedback from a base station such as an eNB (e.g., eNB <NUM>, <NUM>, <NUM>), channel conditions, a modulation scheme of the UE, and/or the like. For example, the UE may receive feedback from the eNB indicating to increase or decrease transmission power based at least in part on whether reception or decoding of previous signals, transmitted by the UE, is successful. The UE may increase transmission power when reception or decoding of the previous signals is poor or unsuccessful, and may decrease transmission power when reception or decoding of the previous signals is successful.

In some aspects, the UE may be associated with a maximum output power. The maximum output power may identify a maximum transmission power at which the UE is permitted to transmit signals. For example, a UE operating in a 3GPP frequency band (e.g., an LTE UE) may, for example, be a Power class <NUM> UE, and the maximum output power associated with such a UE may be approximately <NUM> decibel-milliwatts (dBm) within a particular tolerance that is determined according to the 3GPP frequency band in which the UE operates. When uplink performance or channel conditions of the UE are sufficiently poor, the transmission power of the UE may approach or reach the maximum output power as a result of, for example, the eNB feedback process. A scenario in which the transmission power approaches or reaches the maximum output power may be referred to as a power-limited uplink scenario.

In some aspects, the UE may adjust the transmission power value specified by the eNB based at least in part on a maximum power reduction (MPR) value to determine a transmission power of the UE. For example, due to the flexibility of bandwidth and modulation of the LTE air interface, the UE may adjust the transmission power value that is actually used by the UE to a value below the value indicated by the eNB. The MPR value used to decrease the transmission power value may be determined using one or more criteria, such as whether the uplink signal is associated with single carrier or carrier aggregation, as well as other criteria described in more detail below. For example, the UE may use a higher MPR value, and therefore a lower transmission power value, for signals associated with carrier aggregation than for signals associated with a single carrier. By decreasing the transmission power value, the UE may improve uplink performance and reduce interference on the LTE air interface.

In some aspects, the UE may configure a primary component carrier (PCC) and a secondary component carrier (SCC) for uplink and/or downlink traffic of the UE in accordance with CA. The UE may transmit uplink signals associated with the PCC and/or the SCC at particular transmission powers. In some aspects, the UE may adjust the transmission powers associated with the PCC and/or the SCC according to priority of the PCC and/or the SCC. For example, consider a situation where uplink performance or channel conditions are sufficiently poor to cause both the PCC and the SCC to be configured to transmit at a maximum output power for a serving cell associated with the PCC. Assume that uplink control information (UCI) of the PCC and/or the SCC is carried by the PCC. In such a case, the UE may give priority to the PCC, which carries the UCI, over the SCC. Accordingly, the UE may reduce the transmission power of the SCC to a lower value (e.g., to zero, to substantially zero, and/or the like) to ensure that the UE can provide sufficient power for the PCC. This process may be referred to as priority-based power scaling.

When determining transmission strengths of a PCC and an SCC, in a case where the transmission power of the SCC has been reduced (e.g., to zero, to substantially zero, and/or the like) due to priority-based power scaling, the UE may employ an MPR value for the PCC that is determined using a carrier aggregation approach, even though the PCC is effectively being used as a single carrier (e.g., since the SCC's transmission power is zero or substantially zero). As stated above, the MPR value for carrier aggregation may be greater than the MPR value for single carrier, which may lead to greater reduction or diminution of transmission power than using an MPR value for single carrier. This may degrade uplink performance of the UE and/or impact decoding of uplink transmissions of the UE, which may be problematic in situations where uplink performance or channel conditions are sufficiently poor to cause the UE to transmit the PCC at substantially the maximum output power.

Techniques and apparatuses according to the invention, described herein, relate to a situation (e.g., in a carrier aggregation scenario) where transmission power of the SCC has been reduced (e.g., to zero, to substantially zero, and/or the like) due to priority based power scaling. In such a case, the UE may accordingly determine the transmission strength of the PCC using the MPR value for single carrier (e.g., rather than the carrier aggregation MPR value). In this way, transmission strength of the PCC imay be increased in such a case, thereby improving uplink performance of the UE. This may lead to better reliability in decoding the PCC during power-limited uplink carrier aggregation scenarios (e.g., when the UE is at a cell edge of the eNB, during peak uplink throughput, etc.). Furthermore, by adjusting the MPR value determination after identifying the priority-based power scaling condition, key performance indicators on the UE and/or the network side may be improved in channel conditions similar to those associated with the priority based power scaling.

<FIG> and <FIG> are diagrams illustrating examples <NUM> of adjusting transmit power for power-limited uplink carrier aggregation scenarios, in accordance with various aspects of the present disclosure.

As shown in <FIG>, and by reference number <NUM>, a UE <NUM>, <NUM> may configure uplink carrier aggregation with regard to component carriers provided by an eNB <NUM>, <NUM>, <NUM>. As shown by reference number <NUM>, a PCC of the UE <NUM>, <NUM> may be associated with a <NUM> bandwidth, corresponding to <NUM> resource blocks. As further shown, an SCC of the UE <NUM>, <NUM> may also be associated with <NUM> bandwidth corresponding to <NUM> resource blocks. As further shown, the PCC and the SCC are both associated with QPSK modulation schemes.

As shown by reference number <NUM>, the UE <NUM>, <NUM> may receive scheduling and control information from the eNB <NUM>, <NUM><NUM>. As shown by reference number <NUM>, the scheduling and control information may include uplink scheduling information indicating that <NUM> resource blocks are allotted for the uplink (e.g., of <NUM> total resource blocks associated with the PCC and the SCC).

As further shown, the UE <NUM>, <NUM> may determine transmission power values of <NUM> dBm for the PCC and the SCC based at least in part on the scheduling and control information. For example, as shown by reference number <NUM>, the eNB <NUM>, <NUM>, <NUM> may provide transmission power control (TPC) information identifying a transmission power value of <NUM> dBm (e.g., equal to the maximum output power of an LTE UE <NUM>, <NUM>) at which the UE <NUM>, <NUM> is to transmit the PCC and the SCC. In some aspects, the eNB <NUM>, <NUM>, <NUM> may specify the transmission power value based at least in part on poor channel conditions and/or uplink performance of the PCC and the SCC.

The UE <NUM>, <NUM> may determine an MPR value for adjusting the transmission power specified by the eNB <NUM>, <NUM>, <NUM>, to determine the transmission power value to be employed by the UE <NUM>, <NUM>. For example, the UE <NUM>, <NUM> may use one or more LTE specifications (e.g., 3GPP specification <NUM> starting at section <NUM>. <NUM>, 3GPP specification <NUM>, etc.) to determine one or more MPR values, for example, for carrier aggregation based at least in part on the resource block allocation, the modulation scheme, and the uplink bandwidth. As shown here, the UE <NUM>, <NUM> may determine an MPR value of <NUM> dB. When the MPR value of <NUM> dB is applied to the transmission power value of <NUM> dBm specified by the eNB <NUM>, <NUM>, <NUM>, the UE <NUM>, <NUM> may determine a transmission power value of <NUM> dBm, as shown in <FIG>.

In some aspects, and for example, the UE <NUM>, <NUM> may determine the MPR value for carrier aggregation according to Table <NUM>. 3A-<NUM> of 3GPP specification <NUM>, as shown below:.

Here, the UE <NUM>, <NUM> may identify the MPR value of <NUM> dB according to the lower QPSK row of Table <NUM>. For example, the PCC and the SCC are each associated with a QPSK modulation scheme, respective bandwidths of <NUM> RB (e.g., <NUM> RB + <NUM> RB), and a cumulative resource block allocation of <NUM> RBs (e.g., > <NUM>). Therefore, the UE <NUM>, <NUM> selects the MPR value of ≤ <NUM> dB, and uses <NUM> dB as the MPR value.

The MPR value of <NUM> dB for carrier aggregation, determined in connection with <FIG>, may be different than if the UE <NUM>, <NUM> determined an MPR value for a single carrier. For example, the UE <NUM>, <NUM> may determine an MPR value of <NUM> dB for single carrier, which may lead to a transmission power value of <NUM> dBm, as described in more detail below. This higher transmission power (e.g., determined using the single carrier approach) may lead to improved network performance with regard to the UE <NUM>, <NUM> when only one component carrier (e.g., the PCC) is transmitted at such a transmission power value, thus improving performance of the UE <NUM>, <NUM> in a power-limited uplink carrier aggregation scenario.

As shown by reference number <NUM>, the scheduling and control information (at reference number <NUM>) may identify downlink scheduling information indicating that the PCC is scheduled to carry uplink control information for the PCC and the SCC.

As shown by reference number <NUM>, the UE <NUM>, <NUM> may identify a priority-based power scaling condition based at least in part on the transmission power values of the PCC and the SCC. For example, the UE <NUM>, <NUM> may identify the priority-based power scaling condition when the transmission power values satisfy a threshold (e.g., when the PCC and the SCC are each to be transmitted at <NUM> percent of the maximum output power of the UE <NUM>, <NUM>, at <NUM> percent of the maximum output power of the UE <NUM>, <NUM>, at <NUM> percent of the maximum output power of the UE <NUM>, <NUM>, and/or the like). In some aspects, the UE <NUM>, <NUM> may identify the priority-based power scaling condition during a power-limited uplink carrier aggregation scenario, such as a scenario when the UE <NUM>, <NUM> is transmitting uplink carrier aggregation traffic at a peak uplink throughput, when the UE <NUM>, <NUM> is isolated from the eNB <NUM>, <NUM>, <NUM>, when the UE <NUM>, <NUM> is located at a cell edge of the eNB <NUM>, <NUM>, <NUM>, and/or the like.

As further shown, the UE <NUM>, <NUM> may decrease the SCC transmission power value, for example, to zero based at least in part on identifying the priority-based power scaling condition and based at least in part on the PCC carrying the UCI to be transmitted on the uplink. However, the MPR value for the PCC may be equal to <NUM> dB when the MPR value is computed for carrier aggregation, which leads to a transmission power (e.g., configured by the UE <NUM>, <NUM>) of the PCC of <NUM> dBm, as shown by reference number <NUM>. Therefore, the UE <NUM>, <NUM> may transmit the PCC at diminished power as compared to a single carrier case (e.g., with an MPR value of <NUM> dB). Transmitting the PCC at diminished power may lead to diminished reception of the PCC at the eNB <NUM>, <NUM>, <NUM> in a power-limited uplink carrier aggregation scenario. Thus, as described in connection with <FIG>, below, it may be beneficial to use a single carrier MPR value to compute the transmission power.

As shown in <FIG>, and by reference number <NUM>, the UE <NUM>, <NUM> may identify an MPR value computed for single carrier based at least in part on decreasing the transmission power of the SCC due to identifying the priority-based power scaling condition. For example, the MPR value computed for single carrier may be <NUM> dB. In some aspects, and for example, the UE may determine the MPR value for single carrier according to Table <NUM>. <NUM>-<NUM> of 3GPP specification <NUM>, as shown below:.

Here, the UE <NUM>, <NUM> may identify the MPR value of <NUM> dB according to the QPSK row of Table <NUM>. <NUM>-<NUM>. For example, the PCC is associated with a QPSK modulation scheme and a bandwidth of <NUM> RB (e.g., <NUM>). Assume that the PCC is associated with a resource block allocation of <NUM> RB of the <NUM> RB of the PCC and the SCC (e.g., NRB > <NUM>). Therefore, the UE <NUM>, <NUM> selects the MPR value of ≤ <NUM> dB, and uses <NUM> dB as the MPR value.

As shown by reference number <NUM>, the UE <NUM>, <NUM> may increase the transmission power value of the PCC based at least in part on the MPR value for single carrier. For example, as shown by reference number <NUM>, the UE <NUM>, <NUM> may increase the transmission power value from a value of <NUM> dBm, shown in <FIG>, to <NUM> dBm, shown in <FIG>. In some aspects, the UE <NUM>, <NUM> may configure the transmission power value according to the MPR value for single carrier. For example, rather than increasing the transmission power from <NUM> dBm to <NUM> dBm, the UE <NUM>, <NUM> may simply use a transmission power of <NUM> dBm. In this way, the UE <NUM>, <NUM> configures transmission power of the PCC for single carrier in a situation where transmission power of the SCC has been dropped or diminished (e.g., for power-limited uplink carrier aggregation scenarios). Thus, uplink performance of the UE <NUM>, <NUM> is improved.

Other examples are possible and may differ from what was described with respect to <FIG> and <FIG>.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a user equipment, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a user equipment (e.g., UE <NUM>, <NUM>) performs adjusting of transmit power for power-limited uplink carrier aggregation scenarios.

As shown in <FIG>, in some aspects, process <NUM> may include decreasing a first value of a transmission power of a first component carrier relative to a second value of a transmission power of a second component carrier based at least in part on the second component carrier carrying control information, wherein the second value of the transmission power of the second component carrier is based at least in part on a first MPR value identified for carrier aggregation (block <NUM>). For example, the user equipment may decrease a first value of a transmission power of a first component carrier (e.g., an SCC) relative to a second value of a transmission power of a second component carrier (e.g., a PCC) based at least in part on the second component carrier carrying control information. The second value of the transmission power (e.g., configured by the UE) of the second component carrier may be based at least in part on a first MPR value identified for carrier aggregation.

As shown in <FIG>, in some aspects, process <NUM> may include increasing the transmission power of the second component carrier to a third value based at least in part on a second MPR value identified for single carrier (block <NUM>). For example, the user equipment may increase the transmission power of the second component carrier (e.g., the PCC) to a third value based at least in part on a second MPR value identified for single carrier.

In some aspects, the user equipment may identify the first MPR value for carrier aggregation. In some aspects, the user equipment may identify the second MPR value for single carrier after decreasing the first value of the transmission power of the first component carrier, wherein decreasing the first value of the transmission power of the first component carrier includes dropping the first component carrier due to priority being given to the second component carrier.

In some aspects, the user equipment may decrease the first value of the transmission power of the first component carrier relative to the second value of the transmission power of the second component carrier based at least in part on a total transmission power of the first component carrier and the second component carrier satisfying a threshold.

In some aspects, the second component carrier may carry uplink control information of at least one of the first component carrier or the second component carrier.

In some aspects, the user equipment may decrease the first value of the transmission power of the first component carrier to substantially zero.

In some aspects, the first component carrier may include a secondary component carrier and the second component carrier may include a primary component carrier.

In some aspects, at least the second value of the transmission power of the second component carrier may be determined based at least in part on at least one of: a resource block allocation of the first component carrier and the second component carrier; an uplink bandwidth of the first component carrier and the second component carrier; or modulation types of the first component carrier and the second component carrier.

In some aspects, at least the third value of the transmission power of the second component carrier may be determined based at least in part on at least one of an uplink bandwidth of the second component carrier, or a modulation type of the second component carrier.

In some aspects, the second value of the transmission power of the second component carrier may be a first configured maximum output power for a serving cell associated with the second component carrier, the first configured maximum output power (e.g., configured by the UE) may be based at least in part on the first MPR value. The third value of the transmission power of the second component carrier may be a second configured maximum output power for a serving cell associated with the second component carrier, the second configured maximum output power (e.g., configured by the UE) may be based at least in part on the second MPR value.

In aspects, an MPR value may refer to at least one of a regular MPR value, an A-MPR (Additional Maximum Power Reduction) value, or a P-MPR (Power Management Maximum Power Reduction) value.

Claim 1:
A method of wireless communication, the method being performed by a user equipment (<NUM>, <NUM>) and comprising:
configuring a primary component carrier, PCC, and a secondary component carrier, SCC;
determining to prioritize the primary component carrier over the secondary component carrier;
transmitting an uplink signal to a base station (<NUM>, <NUM>);
configuring a transmission power of a subsequent uplink signal based at least in part on feedback received from the base station (<NUM>, <NUM>) in response to the uplink signal, wherein the feedback indicates to increase or to decrease transmission power based at least in part on whether reception or decoding of the uplink signal is successful, wherein configuring the transmission power comprises:
decreasing a first value of a transmission power of the secondary component carrier relative to a second value of a transmission power of the primary component carrier based at least in part on the primary component carrier carrying control information for the user equipment (<NUM>, <NUM>),
wherein the second value of the transmission power of the primary component carrier is based at least in part on a first maximum power reduction value for carrier aggregation, and
wherein decreasing the first value of the transmission power of the secondary component carrier relative to the second value of the transmission power of the primary component carrier comprises:
decreasing the first value of the transmission power of the secondary component carrier to substantially zero;
determining, based on the transmission power of the secondary component carrier being decreased to substantially zero, to determine the transmission strength of the primary component carrier by using a second maximum power reduction value, the second maximum power reduction value being associated with single carrier instead of carrier aggregation; and
increasing the transmission power of the primary component carrier to a third value based at least in part on the second maximum power reduction value for single carrier.