HK1167555B - Method and apparatus for uplink power control in a multicarrier wireless communication system - Google Patents

Description

Method and apparatus for uplink power control in a multi-carrier wireless communication system

Priority requirements according to 35U.S.C. § 119

This patent application claims priority from provisional application No.61/175,405 entitled "uplink power control in multi-carrier operation," filed on 4.5.2009 and assigned to the assignee of the present application and hereby expressly incorporated by reference.

Background

FIELD

The present disclosure relates generally to wireless communication systems. In particular, the present disclosure relates to methods and apparatus for uplink power control in a multi-carrier wireless communication system.

Introduction to

Wireless communication systems are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting multi-user communication by sharing the available system resources (e.g., bandwidth and transmit power). 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, 3GPP Long Term Evolution (LTE) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and single carrier FDMA (SC-FDMA) systems.

In a communication system where there are multiple uplink and downlink carriers, certain rules should be defined to specify power control for the multiple uplink carriers. Although in LTE release 8 there is only one uplink paired with one downlink and the uplink power control is configured to control the transmit power of each channel on this one uplink carrier, such a scheme is not applicable to multi-carrier systems with multiple configurations of uplink and downlink (e.g., LTE-advanced).

Accordingly, there is a need in the art for a method and apparatus for providing uplink control for multiple uplinks in a multi-carrier system.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

According to one aspect of the disclosure, a wireless communications apparatus may include a controller configured to determine a power required for at least one of a plurality of carriers and generate at least one of a plurality of power control commands for the at least one of the plurality of carriers based on the determination.

According to another aspect of the disclosure, a method for wireless communication may include determining a power required for at least one of a plurality of carriers and generating at least one of a plurality of power control commands for the at least one of the plurality of carriers based on the determination.

According to another aspect of the disclosure, an apparatus may include means for determining a power required for at least one of a plurality of carriers, and means for generating at least one of a plurality of power control commands for the at least one of the plurality of carriers based on the determination.

According to another aspect of the disclosure, a computer program product may include a computer-readable medium including code for determining a power required for at least one of a plurality of carriers, and code for generating at least one of a plurality of power control commands for the at least one of the plurality of carriers based on the determination.

According to yet another aspect of the disclosure, a wireless communications apparatus can include a controller configured to decode power control commands for at least one of a plurality of carriers and allocate power among the at least one of the plurality of carriers based on the power control commands.

According to yet another aspect of the disclosure, a method for wireless communication may include decoding power control commands for at least one of a plurality of carriers and allocating power among the at least one of the plurality of carriers based on the power control commands.

According to yet another aspect of the disclosure, an apparatus may include means for decoding power control commands for at least one of a plurality of carriers, and means for allocating power among the at least one of the plurality of carriers based on the power control commands.

According to yet another aspect of the disclosure, a computer program product may include a computer-readable medium including code for decoding power control commands for at least one of a plurality of carriers, and code for allocating power among the at least one of the plurality of carriers based on the power control commands.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed and the present description is intended to include all such aspects and their equivalents.

Brief Description of Drawings

The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which:

FIG. 1 illustrates aspects of a wireless communication system;

fig. 2 illustrates a communication system including an uplink and a downlink between a base station and an access terminal;

FIG. 3 illustrates some aspects of a protocol stack for a communication system;

fig. 4 illustrates a radio frame structure and a resource grid showing resource blocks and resource elements;

fig. 5 illustrates an example of a multi-carrier system that facilitates uplink power control in a wireless communication environment;

fig. 6 illustrates an example of an uplink/downlink paired with an anchor carrier;

fig. 7 illustrates an example of an access terminal that facilitates uplink power control in a multi-carrier communication system.

Fig. 8 is a block diagram of an example base station that facilitates uplink power control in a multi-carrier communication system;

fig. 9 is a flow chart illustrating an example of a process for uplink power control in a multi-carrier communication system from the perspective of an access terminal;

fig. 10 is a flowchart illustrating an example of a process of uplink power control in a multicarrier communication system from the perspective of a base station;

fig. 11 is an illustration of an example system that facilitates uplink power control in a multi-carrier communication system; and

fig. 12 is an illustration of an example system that facilitates uplink power control in a multi-carrier communication system.

Detailed Description

Aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It will be apparent, however, that such aspects may be practiced without these specific details.

As used in this application, the terms "component," "module," "system," and the like are intended to include a computer-related entity, such as but not limited to hardware, firmware, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components may reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the internet with other systems by way of the signal.

In addition, various aspects are described herein in connection with a terminal, which may be a wired terminal or a wireless terminal. A terminal can also be called a system, device, subscriber unit, subscriber station, mobile device, remote station, remote terminal, access terminal, user terminal, communication device, user agent, user device, or User Equipment (UE). A wireless terminal may be a cellular telephone, a satellite telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device having wireless connection capability, a computing device, or other processing device connected to a wireless modem. Moreover, various aspects are described herein in connection with a base station. A base station may be utilized for communicating with wireless terminal(s) and may also be referred to as an access point, node B, evolved node B (eNB), or some other terminology.

Furthermore, the term "or" is intended to mean the same "or" rather than a different "or". That is, unless specified otherwise, or clear from context, the phrase "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, the phrase "X employs a or B" results in satisfaction of any of the following examples: x is A; x is B; or X employs both A and B. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form.

The techniques described herein may be used for various wireless communication 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 Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes wideband CDMA (W-CDMA) and other CDMA variants. In addition, cdma2000 covers IS-2000, IS-95 and IS-856 standards. TDMA systems may implement radio technologies such as global system for mobile communications (GSM). The OFDMA system may implement radio technologies such as evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11(Wi-Fi), IEEE802.16(WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM are described in literature from an organization named "third Generation partnership project (3 GPP)". In addition, cdma2000 and UMB are described in documents from an organization named "third generation partnership project 2" (3GPP 2). In addition, these wireless communication systems may also include peer-to-peer (e.g., mobile-to-mobile) ad hoc (ad hoc) network systems that often use unpaired unlicensed spectrum, 802.xx wireless LANs, bluetooth, and any other short-or long-range wireless communication technologies.

Various aspects or features will be presented in terms of systems that may include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc. and/or may not fully include the devices, components, modules etc. discussed in connection with the figures. Combinations of these approaches may also be used.

Additionally, in the subject description, the word "exemplary" is used to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion.

Fig. 1 shows a wireless communication system 100, which may be a 3gpp lte-UTRA system. System 100 may include base station 110 and other network entities as described by 3 GPP. A base station may be a fixed station that communicates with the access terminals. Each base station 110 may provide communication coverage for a particular geographic area. To increase network capacity, the overall coverage area of a base station may be divided into multiple (e.g., three) smaller areas. Each smaller area may be served by a respective base station subsystem. In 3GPP, the term "cell" can refer to a smaller coverage area of a base station and/or a base station subsystem serving that coverage area.

System controller 130 may include a Mobility Management Entity (MME) and a serving gateway (S-GW), and may couple to and provide coordination and control for a set of base stations. The S-GW may support data services such as packet data, voice over IP (VoIP), video, messaging, etc. The MME may be responsible for path switching between the source and target base stations at the time of handover. System controller 130 may be coupled to a core and/or a data network (e.g., the internet) and may communicate with other entities (e.g., remote servers and terminals) coupled to the core/data network.

Terminals 120 may be dispersed throughout the network, and each access terminal may be stationary or mobile. An access terminal may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base stations to the access terminals, and the uplink (or reverse link) refers to the communication link from the access terminals to the base stations. In fig. 1, a solid line with double arrows indicates active communication between a base station and an access terminal.

Fig. 2 illustrates a system 200 that includes an uplink 212 and a downlink 214 between a base station 204 and an access terminal 208. Base station 204 and access terminal 208 can correspond to base station 110 and access terminal 120 shown in fig. 1 uplink 212 refers to transmissions from access terminal 208 to base station 204; downlink 214 refers to transmissions from base station 204 to access terminal 208.

Fig. 3 illustrates some aspects of a protocol stack for a communication system. Both base station 204 and access terminal 208 can include the protocol stack 300 illustrated in fig. 3. The protocol stack may include a physical layer (PHY)316, a Medium Access Control (MAC)318, and higher layers 320.

The MAC layer 318 may receive data from higher layers 320 via one or more logical channels 322. The MAC layer 318 may then perform various functions such as mapping between logical channels 322 and transport channels 324, multiplexing/demultiplexing individual PDUs of logical channels 322 into/from transport blocks of transport channels 324, error correction, traffic volume measurement reporting, priority handling between individual logical channels 322 of access terminals, priority handling between individual access terminals via dynamic scheduling, transport format selection, padding, and so forth.

The physical layer 316 may be configured to provide a plurality of physical control channels 326. The access terminal 204 may be configured to monitor the set of control channels. The physical layer 316 may also provide data transfer services via physical channels 326. Some of the physical channels used for downlink signaling may be a Physical Downlink Control Channel (PDCCH), a physical hybrid ARQ indicator channel (PHICH), and a Physical Downlink Shared Channel (PDSCH). Some physical channels used for uplink signal transmission may be a Physical Uplink Control Channel (PUCCH), a Physical Uplink Shared Channel (PUSCH), and a Physical Random Access Channel (PRACH).

System 100 may use orthogonal OFDMA for the downlink and SC-FDMA for the uplink. The basic idea behind OFDM is to divide the available spectrum into several sub-carriers. To obtain high spectral efficiency, the frequency responses of the subcarriers are overlapping and orthogonal. In system 100, OFDMA downlink transmissions and uplink transmissions may be organized into radio frames having a duration of 10 ms. The frame structure is applicable to both Frequency Division Duplexing (FDD) (frequency division multiplexing is applied to separate outgoing and return signals) and Time Division Duplexing (TDD) (time division multiplexing is applied to separate outgoing and return signals). As shown in fig. 4, each radio frame is 10ms long and consists of 20 slots of 0.5ms, numbered 0 to 19. A subframe is defined as two consecutive slots, where subframe i consists of slots 2i and 2i + 1. A subframe may be referred to as a Transmission Time Interval (TTI). For FDD, 10 subframes are available for downlink transmission and 10 subframes are available for uplink transmission in each 10ms interval. The uplink and downlink transmissions are separated in the frequency domain. For TDD, subframes are allocated either to downlink transmissions or to uplink transmissions. Subframe 0 and subframe 5 may always be allocated for downlink transmission.

The signal in each time slot can be composed of N_SC ^RBA number of subcarriers and N_SYMBA resource grid of symbols, N_SYMBThe symbols may be OFDM symbols for downlink or SC-FDMA symbols for uplink. In the case of multi-antenna transmission from the base station 110, each antenna port may define a resource grid. The antenna port may be defined by a downlink reference signal (DLRS), which is unique within the cell. Each element in the resource grid of antenna port p may be referred to as a resource element and is uniquely identified by an index pair (k, l), where k and l are indices in the frequency and time domains, respectively. One, two, four or more antenna ports may be supported. A physical resource block may be defined as N in the time domain_SYMBOne consecutive symbol and N in the frequency domain_SC ^RBOne (e.g., 12) consecutive subcarriers. Resource block is thus composed of N_SYMBxN_SC ^RBA resource element.

Data transmitted over the system 100 may be categorized as either non-real time (NRT) data or Real Time (RT) data. Examples of NRT data include data communicated during web browsing by or text messaging to an access terminal, while examples of RT data are voice communications between access terminals.

Data packets (both NRT and RT) are transmitted from the base station to the access terminal in the PDSCH. Various Modulation and Coding Schemes (MCSs) are supported on the PDSCH. Modulation schemes include Quadrature Phase Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM), such as 16-QAM and 64-QAM. Various code rates for error correction may be used. The combination of modulation scheme and code rate may result in a large number (e.g., 30) of possible MCSs.

In LTE based systems (e.g., 3GPP release 8), uplink power control may be a combination of open-loop and closed-loop power control. Using open loop power control, the access terminal estimates the downlink path loss to facilitate power control. With closed loop, the base station may explicitly control the uplink transmit power via power control commands. Transmission and power control signaling without uplink data may occur on the PUCCH; while control signaling in the presence of uplink data may occur on the PUSCH.

Fig. 5 is an example of a multi-carrier system that facilitates uplink power control in a wireless communication environment. As shown in fig. 5, the multi-carrier system 500 may include uplink carriers ULC1506, ULC2508 and downlink carriers DLC1510, DLC2512, DLC3514 between the base station 502 and the access terminal 504. Base station 502 and access terminal 504 may correspond to base station 110 and access terminal 120 shown in fig. 1. The system 500 is shown as being asymmetric in the sense that the number of uplink carriers 506, 508 is not equal to the number of downlink carriers 510, 512, 514. Although only two uplink carriers and three downlink carriers are shown, system 500 may be configured to include any number of uplink and downlink carriers. System 500 can also be a symmetric system with an equal number of uplink and downlink carriers.

System 500 is also configured to support carrier pairing between uplink and downlink carriers. The pairing may be between one or more downlink carriers and one or more uplink carriers. In one configuration, at least one downlink carrier is paired with a plurality of uplink carriers or a plurality of downlink carriers is paired with at least one uplink carrier such that a paired set of downlink and uplink carriers includes at least three carriers.

System 500 can include any number of disparate base stations similar to base station 502 and/or any number of disparate access terminals similar to access terminal 504. According to an illustration, system 500 can be an LTE-a based system; however, claimed subject matter is not so limited.

To facilitate multi-carrier operation, system 500 can provide power control on a per-carrier basis. Power control per carrier enables flexibility in operating on separate frequency bands and for the purpose of interference management.

In an aspect, the access terminal 504 may decide the transmit power of the data transmission on the PUSCH. According to an example, the transmit power P of the multiple carriers indicated by the carrier index k in the subframe i can be determined by the following equation 1_PUSCH(i, k) (in dBm):

P_PUSCH(i，k)＝min{P_MAX，10log₁₀(M_PUSCH(i，k))+P_{O_PUSCH}(j，k)+α(j，k)·PL(k)+Δ_TF(i，k)+f(i，k)}

in accordance with the present description, all components are defined per uplink carrier as specified by carrier index k. In formula 1, P_MAXIs the maximum allowed transmit power as configured in higher layers, e.g., in System Information Blocks (SIBs). M_PUSCH(i, k) is the bandwidth of the PUSCH resource assignment expressed in number of resource blocks valid for subframe i. P_{O_PUSCH}(j, k) is a parameter configured by the sum of an 8-bit cell-specific nominal component and a 4-bit access terminal-specific component, and is provided by higher layers for both j 0 and j 1.α (j, k) is a 3-bit cell-specific parameter provided by higher layers that weights the effect of path loss estimation in power control decisionsThe calculated downlink path loss estimate. In one example, the path loss estimate is based on the difference between the reference signal power as provided by the higher layers and the higher layer filtered reference signal received power. Delta_TF(i, k) is a power offset specific to a particular information transmission format and/or a particular modulation and coding scheme. Delta_TF(i, k) can be varied from 10log₁₀(2^(MPR)(Ks)-1) Providing, wherein K_SGiven by deltaMCS-Enabled, which is an access terminal-specific parameter provided by each higher layer, and where MPR TBS/N_RETBS is transport block size, and N_REIs the number of resource elements. The parameter f (i, k) is the power control adjustment status as provided by the base station and is determined by_PUSCHIt is determined that,_PUSCHis an access terminal correction value called a Transmit Power Control (TPC) command._PUSCHIs TPC information transmitted from the base station to the access terminal via the PDCCH or PDSCH.

In an aspect, the access terminal 504 may also determine a transmit power for data transmission on the PUCCH. According to an example, the transmit power P of a signal transmitted in subframe i for multiple carriers (as indicated by carrier index k) through PUCCH via uplink may be decided by the following equation 2_PUCCH(i，k)：

P_PUCCH(i，k)＝min{P_MAX，P_{0_PUCCH，k}+PL(k)+h(n_CQI，n_HARQ，k)+Δ_{F_PUCCH}(TF, k) + g (i, k) } according to the present description, all components are defined per unit carrier as specified by the carrier index k. Delta for each PUCCH Transport Format (TF)_{F_PUCCH}(TF, k) is provided by RRC. P_{0_PUCCH，k}Is a parameter configured by the sum of the 5-bit cell-specific parameter provided by each higher layer and the access terminal-specific component given by the RRC. g (i, k) is represented by_PUCCHThe factor of the decision is taken to be,_PUCCHalso TPC commands._PUCCHIs TPC information transmitted from the base station to the access terminal via the PDCCH or PDSCH.

Power control commands (e.g., TPC) may be generated and signaled by the base station 502. Power control commands for the PUSCH may be included in the uplink grant, while power control commands for the PUCCH may be communicated in the downlink grant. Further, base station 502 can be directed to utilizing Downlink Control Information (DCI) to communicate power control commands for a set of access terminals. DCI formats 3 and 3A may be used for PUCCH and PUSCH with power adjustment of 2 bits or 1 bit for each carrier, respectively. In the multi-carrier system 500, multi-carrier uplink and/or downlink grants may carry access terminal TPC commands for all configured access terminals and may be transmitted by the base station 502 on any downlink carrier. The access terminal 504 may monitor one or a large number of downlink carriers (e.g., anchor carriers) of the multi-carrier grant. The base station 502 may use Radio Resource Control (RRC) signaling to inform the access terminal 504 on which downlink carriers to monitor for possible grants.

Fig. 6 shows a block diagram illustrating an example of downlink/uplink carrier pairing for system 500. As shown in fig. 6, ULC1506 may be paired with DLC1510 (shown with solid arrows 602), while ULC2508 may be paired with DLC2512 and DLC3514 (shown with solid arrows 604, 606). ULC1506 may receive uplink control information for DLC1510, while ULC2508 may receive uplink control information for DLC2512 and DLC 3514. The uplink control information may include downlink hybrid automatic repeat request (HARQ) feedback and Channel Quality Indicator (CQI) feedback. Similarly, DLC1 may receive downlink control information for ULC1506, while DLC2512 and DLC3514 may receive downlink control information for ULC 2508. The downlink control information may include uplink grants, downlink grants, and uplink HARQ feedback.

The carrier pairing may be semi-static or dynamic, as determined by the base station 502. For semi-static pairing, the base station 502 can inform all access terminals 504, 120 of the pairing by broadcasting system information in the SIB. Alternatively, the base station 502 can inform each access terminal 504, 120 of the pairing in an RRC connection setup message with dedicated signaling through RRC signaling. For dynamic pairing, the base station 110 may inform the access terminal 120 of the pairing through MAC signaling included in the grant message.

Which carrier the control information is sent on may also depend on whether there are any designated anchor carriers. If an anchor carrier exists in the system, control information for one or more corresponding carriers can be sent on the anchor carrier even if the carriers are outside of the pairing. For example, if DLC1510 may be designated as an anchor carrier for downlink carriers 510, 512, 514, and ULC1506 may be designated as an anchor carrier for uplink carriers 506, 508, ULC1506 will receive control information for downlink carriers 510, 512, 514, and DLC1510 will receive control information for uplink carriers 506, 508.

One or more anchor carriers may be defined for each of the respective uplink and downlink carriers. The base station 502 can inform the access terminals 504, 120 of the anchor carrier in a SIB or through dedicated signaling such as RRC signaling. The base station 502 notifies the access terminals 504, 120 of the uplink/downlink pairing and any anchor carriers in the SIB. The SIB may include carrier location (i.e., carrier center frequency), carrier bandwidth, carrier designation (uplink/downlink), carrier pairing, and anchor carrier information, as well as uplink/downlink grants on which particular carrier and on which particular resources TPC commands are expected to be carried. In one configuration, some control information may be sent over the anchor carrier, while other control information may be sent over the paired carrier. For example, the base station 110 may indicate by broadcast or RRC signaling whether the uplink TPC command is to be sent on the paired downlink carrier or the designated downlink anchor carrier.

The base station 502 can also analyze the power headroom report provided by the access terminal 504. The power headroom report indicates the difference between the maximum transmit power available to the access terminal 504 and the transmit power to be used for the carrier (or the entirety of all carriers). In this manner, base station 502 can estimate the power limit of access terminal 504. Base station 502 may also facilitate generating power control commands and/or facilitate scheduling decisions. For example, base station 502 can identify a situation when an access terminal 504 cannot support multiple carriers on which the access terminal 504 should not be scheduled.

In another aspect, the base station 502 can employ an overload indicator. The overload per carrier indicator provides better control in situations when the carriers are not uniformly negatively charged and shared. For example, in the case of an asymmetric carrier configuration, as shown in system 500, whether one or more downlink carriers may carry an overload indicator depends on the type of carrier asymmetry. If the number of uplink carriers is greater than the number of downlink carriers, only one downlink carrier will carry an overload indicator for the corresponding uplink based on the uplink/downlink carrier pairing. On the other hand, if the number of uplink carriers is less than the number of downlink carriers, more than one downlink carrier may carry an overload indicator for the corresponding uplink based on the uplink/downlink carrier pairing. The overload indicator can also be transmitted on the anchor carrier regardless of the uplink/downlink pairing.

In another aspect, the access terminal 504 can facilitate configuration of uplink transmit power for each uplink carrier. In one example, access terminal 504 may allocate power over multiple carriers. For example, the access terminal 504 may prioritize the carriers to provide the required power according to the importance of the carriers. In one example, the anchor carrier may have a higher priority than other carriers, and thus may receive the required power first. In another example, the uplink carrier carrying the highest priority data may have a higher priority than the other carriers, and thus may receive the required power first. Alternatively, a prioritized list indicating carrier priorities may be communicated by the base station 502 to the access terminal 504. The access terminal 504 may also scale power uniformly across carriers. Further, the base station 502 and/or the access terminal 504 may be configured to meet PUCCH power requirements prior to PUSCH power requirements on any given carrier. However, if control information or upper layer signaling is transmitted on a PUSCH of a high priority carrier, the base station 502 and/or access terminal 504 will accommodate such PUSCH power requirements on the high priority carrier before PUCCH power requirements of a carrier with a lower priority.

Fig. 7 is an illustration of an access terminal that facilitates uplink power control in a multi-carrier communication system. The access terminal 700 may correspond to one of the access terminals 120 shown in fig. 1. As shown in fig. 7, an access terminal 700 can comprise a receiver 702 that receives a plurality of signals from, for instance, one or more receive antennas (not shown), performs typical actions on (e.g., filters, amplifies, downconverts, etc.) the received signals, and digitizes the conditioned signals to obtain samples. Receiver 702 can comprise a plurality of demodulators 704 that can demodulate received symbols from each signal and provide them to a processor 706 for channel estimation, as described herein. Processor 706 can be a processor dedicated to analyzing information received by receiver 702 and/or generating information for transmission by a transmitter 716, a processor that controls one or more components of access terminal 700, and/or a processor that both analyzes information received by receiver 702, generates information for transmission by transmitter 716, and controls one or more components of access terminal 700.

Access terminal 700 can additionally comprise memory 708, memory 708 being operatively coupled to processor 706 and that can store data to be transmitted (e.g., high priority data), received data, information related to available channels, data associated with analyzed signal and/or interference strength, information related to an assigned channel, power, rate, or the like, and any other information suitable for estimating a channel and communicating via the channel. Memory 708 can additionally store protocols and/or algorithms associated with estimating and/or utilizing a channel (e.g., performance based, capacity based, etc.).

It will be appreciated that the data store (e.g., memory 708) described herein can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. By way of illustration, and not limitation, nonvolatile memory can include Read Only Memory (ROM), programmable ROM (prom), electrically programmable ROM (eprom), electrically erasable prom (eeprom), or flash memory. Volatile memory can include Random Access Memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as Synchronous RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct memory bus RAM (DRRAM). The memory 708 of the subject systems and methods is intended to comprise, without being limited to, these and any other suitable types of memory.

Receiver 702 can be further operatively coupled to a controller 710, controller 710 can control uplink power for a plurality of uplink carriers by decoding power control commands for the plurality of uplink carriers and allocating power among the plurality of carriers based on the power control commands. The controller may further control acquisition and storage of power control commands in memory 708 and direct communication with the base station via processor 706 by interfacing with transmitter 714, as discussed with reference to fig. 1. Access terminal 700 also comprises a modulator 712 that modulates and transmits signals via a transmitter 714 to, for example, a base station, a web/internet Access Point Name (APN), and another access terminal, etc. Although depicted as being separate from the processor 706, it is to be appreciated that the controller 710, demodulator 704, and/or modulator 712 can be part of the processor 706 or multiple processors (not shown). Further, the various functions of the controller 710 may be integrated into an application layer, data stack, HTTP stack at the Operating System (OS) level, in an Internet browser application, or in an Application Specific Integrated Circuit (ASIC).

Fig. 8 is an illustration of a system 800 that controls feedback in an asymmetric multicarrier communication system. System 800 includes a base station 802 (e.g., an access point, a femtocell, etc.) that has a receiver 810 that receives signal(s) from one or more access terminals 804 via a plurality of receive antennas 806, and a transmitter 824 that transmits to the one or more access terminals 804 via a transmit antenna 808. Receiver 810 can receive information from receive antennas 806 and is operatively associated with a demodulator 812 that demodulates received information. The demodulated symbols are analyzed by a processor 814, the processor 814 can perform some or all of the functions described above with respect to fig. 1 for base station 808, and is coupled to a memory 816, the memory 816 stores information related to estimating signal (e.g., pilot) strength and/or interference strength, data to be transmitted to or received from mobile device 804 (or a disparate base station (not shown)), and/or any other suitable information related to performing the various acts and functions set forth herein. Processor 814 is further coupled to a controller 818 that can control uplink power on multiple uplink carriers by determining power required for the multiple uplink carriers and generating power control commands for the multiple carriers based on the determination. Although depicted as being separate from the processor 814, it is to be appreciated that the controller 818, demodulator 812, and/or modulator 820 can be part of the processor 814 or processors (not shown).

Fig. 9 is a flowchart illustrating an example of a procedure for uplink power control in a multi-carrier communication system. The process may be implemented in the access terminal 120 of the system 100. As shown in fig. 9, in block 902, a power control command for at least one carrier of a plurality of carriers may be decoded and the process may proceed to block 904. For example, access terminal 120 can receive power control commands from base station 110 on a single downlink carrier and decode the power control commands.

In block 904, power may be allocated among the at least one of the plurality of carriers based on the power control commands, and the process may end. For example, access terminal 120 can allocate and/or adjust power among the multiple carriers based on power control commands received from base station 110.

Fig. 10 is a flowchart illustrating an example of a procedure for uplink power control in a multi-carrier communication system. The process may be implemented in the base station 110 of the system 100. As shown in fig. 10, in block 1002, a power required for at least one carrier of a plurality of carriers may be determined, and the process may proceed to block 1004. For example, base station 110 can receive a power headroom report from access terminal 120 and determine the power required for the plurality of uplink carriers based on the headroom report.

In block 1004, at least one of a plurality of power control commands may be generated for at least one of the plurality of carriers based on the determination, and the process may end. For example, base station 110 may generate and transmit power control commands to access terminal 120 for the multiple uplink carriers based on the power requirements of access terminal 120.

Fig. 11 is an illustration of an example system 1100 that facilitates uplink power control in a multi-carrier communication system. For example, system 1100 can reside at least partially within an access terminal, etc. It is to be appreciated that system 1100 is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). System 1100 includes a logical grouping 1102 of devices that can function cooperatively. For example, logical grouping 1102 may include: means 1104 for decoding a power control command for at least one carrier of the plurality of carriers; and means 1106 for allocating power among the at least one of the plurality of carriers based on the power control commands. Additionally, system 1100 may include a memory 1108 that retains instructions for executing functions associated with devices 1104 to 1106. While shown as being external to memory 1108, it is to be understood that one or more of devices 1104 to 1106 can exist within memory 1108.

Fig. 12 is an illustration of an example system 1200 that facilitates uplink power control in a multi-carrier communication system. For example, system 1200 can reside at least partially within a base station, etc. It is to be appreciated that system 1200 is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). System 1200 includes a logical grouping 1202 of devices that can function cooperatively. For example, logical grouping 1202 may include: means 1204 for determining a power required for at least one of the plurality of carriers; and means 1206 for generating at least one of a plurality of power control commands for at least one of the plurality of carriers based on the determination. Additionally, system 1200 may include a memory 1208 that retains instructions for executing functions associated with devices 1204-1206. While shown as being external to memory 1208, it is to be understood that one or more of devices 1204-1206 can exist within memory 1208.

The various illustrative logics, logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (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, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Further, at least one processor may comprise one or more modules operable to perform one or more of the steps and/or actions described above.

Further, the steps and/or actions of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium may be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. In addition, in some aspects, the processor and the storage medium may reside in an ASIC. Additionally, the ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal. Additionally, in some aspects, the steps and/or actions of a method or algorithm may reside as one or any combination or set of codes and/or instructions on a machine readable medium and/or computer readable medium, which may be incorporated into a computer program product.

In one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is also known as a computer-readable medium. For example, if the software is transmitted from a web 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 the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks (disks) usually reproduce data magnetically, while discs (discs) usually reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

While the foregoing disclosure discusses illustrative aspects and/or embodiments, it should be noted that various changes and modifications could be made herein without departing from the scope of the described aspects and/or embodiments as defined by the appended claims. Furthermore, although elements of the described aspects and/or embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with all or a portion of any other aspect and/or embodiment, unless stated otherwise.

Claims (61)

1. A method for wireless communication, comprising:

determining a power required for a User Equipment (UE) to transmit on at least one of a plurality of uplink carriers, wherein each of the plurality of uplink carriers is paired with a downlink carrier of the UE;

generating at least one of a plurality of power control commands for at least one of the plurality of uplink carriers based on the determination;

communicate an indication to the UE that an uplink grant or a downlink grant is to be transmitted on a paired downlink carrier or anchor carrier; and

communicating at least one of the plurality of power control commands for at least one of the plurality of uplink carriers as part of the uplink grant or the downlink grant.

2. The method of claim 1, wherein each power control command is for each of the plurality of uplink carriers, respectively.

3. The method of claim 1, wherein one of the power control commands is for the plurality of uplink carriers.

4. The method of claim 1, wherein the power control command is generated for transmission on one carrier.

5. The method of claim 4, wherein the one carrier is a downlink carrier.

6. The method of claim 1, further comprising generating an overload indicator indicating an overload of an uplink carrier and transmitting the overload indicator on a downlink carrier paired with the uplink carrier.

7. The method of claim 1, further comprising generating an overload indicator indicating an overload of an uplink carrier and transmitting the overload indicator on the anchor carrier regardless of carrier pairing.

8. The method of claim 1, further comprising prioritizing power allocation among the plurality of uplink carriers based on a carrier priority of each of the plurality of uplink carriers.

9. The method of claim 8, wherein an uplink anchor carrier has a higher carrier priority than other carriers in the plurality of uplink carriers.

10. The method of claim 8, wherein the carrier priority of each of the plurality of uplink carriers corresponds to a priority of data transmitted on each of the plurality of uplink carriers.

11. The method of claim 1, further comprising prioritizing power allocation among the plurality of uplink carriers based on a channel priority of each of the plurality of uplink carriers.

12. The method of claim 11, wherein the channel priority for each of the plurality of uplink carriers is determined based on whether control data is transmitted across a channel of a corresponding one of the plurality of uplink carriers.

13. The method of claim 1, further comprising determining power allocations for the plurality of uplink carriers based on power limitations of a plurality of access terminals corresponding to the plurality of uplink carriers, respectively.

14. The method of claim 1, further comprising determining a power allocation schedule for the plurality of uplink carriers based on a report from an access terminal.

15. The method of claim 14, wherein the report is a power headroom report for the access terminal.

16. The method of claim 1, further comprising determining at least one of a plurality of parameters of a transmit power and a measurement of a physical uplink shared channel for each of the plurality of uplink carriers when generating the power control command.

17. The method of claim 1, further comprising determining at least one of a plurality of parameters of a transmit power and a measurement of a physical uplink control channel for each of the plurality of uplink carriers when generating the power control command.

18. An apparatus for wireless communication, comprising:

means for determining a power required for a user equipment, UE, to transmit on at least one of a plurality of uplink carriers, wherein each of the plurality of uplink carriers is paired with a downlink carrier of the UE;

means for generating at least one of a plurality of power control commands for at least one of the plurality of uplink carriers based on the determination;

means for communicating an indication to the UE that an uplink grant or a downlink grant is to be transmitted on a paired downlink carrier or anchor carrier; and

means for communicating at least one of the plurality of power control commands for at least one of the plurality of uplink carriers as part of the uplink grant or the downlink grant.

19. The apparatus of claim 18, wherein each of the power control commands is for each of the plurality of uplink carriers, respectively.

20. The apparatus of claim 18, wherein one of the power control commands is for the plurality of uplink carriers.

21. The apparatus of claim 18, wherein the plurality of power control commands are generated for transmission on one carrier.

22. The apparatus of claim 21, wherein the one carrier is a downlink carrier.

23. The apparatus of claim 18, further comprising means for generating an overload indicator indicating an overload of an uplink carrier, and means for transmitting the overload indicator on a downlink carrier paired with the uplink carrier.

24. The apparatus of claim 18, further comprising means for generating an overload indicator indicating an overload of an uplink carrier, and means for transmitting the overload indicator on the anchor carrier regardless of carrier pairing.

25. The apparatus of claim 18, further comprising means for prioritizing power allocation among the plurality of uplink carriers based on a carrier priority of each of the plurality of uplink carriers.

26. The apparatus of claim 25, wherein an uplink anchor carrier has a higher carrier priority than other carriers of the plurality of uplink carriers.

27. The apparatus of claim 26, wherein the carrier priority of each of the plurality of uplink carriers corresponds to a priority of data transmitted on each of the plurality of uplink carriers.

28. The apparatus of claim 18, further comprising means for prioritizing power allocation among the plurality of uplink carriers based on a channel priority of each of the plurality of uplink carriers.

29. The apparatus of claim 28, wherein the channel priority for each of the plurality of uplink carriers is determined based on whether control data is transmitted across a channel of a corresponding one of the plurality of uplink carriers.

30. The apparatus of claim 18, further comprising means for determining power allocations for the plurality of uplink carriers based on power limits for a plurality of access terminals corresponding to the plurality of uplink carriers, respectively.

31. The apparatus of claim 18, further comprising means for determining a power allocation schedule for the plurality of uplink carriers based on a report from an access terminal.

32. The apparatus of claim 31, wherein the report is a power headroom report for the access terminal.

33. The apparatus of claim 18, further comprising means for determining at least one of a plurality of parameters of a transmit power and a measurement of a physical uplink shared channel for each of the plurality of uplink carriers when generating the power control command.

34. The apparatus of claim 18, further comprising means for determining at least one of a plurality of parameters of a transmit power and a measurement of a physical uplink control channel for each of the plurality of uplink carriers when generating the power control command.

35. A method for wireless communication, wherein each of a plurality of uplink carriers is paired with a downlink carrier of a user equipment, comprising:

receiving an indication that an uplink grant or a downlink grant is to be received on a paired downlink carrier or anchor carrier;

receiving a power control command for at least one of the plurality of uplink carriers as part of the uplink grant or the downlink grant;

decoding a power control command for at least one of the plurality of uplink carriers; and

allocating power among at least one of the plurality of uplink carriers based on the power control command.

36. The method of claim 35, wherein one of the power control commands is for one of the plurality of uplink carriers, respectively.

37. The method of claim 35, wherein one of the power control commands is for the plurality of uplink carriers.

38. The method of claim 35, wherein the power control command is generated for transmission on one carrier.

39. The method of claim 38, wherein the one carrier is a downlink carrier.

40. The method of claim 35, further comprising receiving an overload indicator on a downlink carrier paired with an uplink carrier indicating overload of the uplink carrier, decoding the overload indicator, and reducing transmit power according to the decoded overload indicator.

41. The method of claim 35, further comprising receiving an overload indicator on the anchor carrier indicating overload of an uplink carrier regardless of carrier pairing, decoding the overload indicator, and reducing transmit power according to the decoded overload indicator.

42. The method of claim 35, further comprising prioritizing power allocation among the plurality of uplink carriers based on a carrier priority of each of the plurality of uplink carriers.

43. The method of claim 42, wherein an uplink anchor carrier has a higher carrier priority than other carriers in the plurality of uplink carriers.

44. The method of claim 42, wherein the carrier priority of each of the plurality of uplink carriers corresponds to a priority of data transmitted on each of the plurality of uplink carriers.

45. The method of claim 35, further comprising prioritizing power allocation among the plurality of uplink carriers based on a channel priority of each of the plurality of uplink carriers.

46. The method of claim 42, further comprising autonomously prioritizing power allocation among the plurality of uplink carriers.

47. The method of claim 42, further comprising prioritizing power allocation among the plurality of uplink carriers based on information received from a base station.

48. An apparatus for wireless communication, wherein each of a plurality of uplink carriers is paired with a downlink carrier of a user equipment, comprising:

means for receiving an indication that an uplink grant or a downlink grant is to be received on a paired downlink carrier or anchor carrier;

means for receiving a power control command for at least one of the plurality of uplink carriers as part of the uplink grant or the downlink grant;

means for decoding a power control command for at least one of the plurality of uplink carriers; and

means for allocating power among at least one of the plurality of uplink carriers based on the power control command.

49. The apparatus of claim 48, wherein one of the power control commands is for one of the plurality of uplink carriers, respectively.

50. The apparatus of claim 48, wherein one of the power control commands is for the plurality of uplink carriers.

51. The apparatus of claim 48, wherein the power control command is generated for transmission on one carrier.

52. The apparatus of claim 51, wherein the one carrier is a downlink carrier.

53. The apparatus of claim 48, further comprising means for receiving an overload indicator indicating an overload of an uplink carrier on a downlink carrier paired with the uplink carrier, means for decoding the overload indicator, and means for reducing transmit power according to the decoded overload indicator.

54. The apparatus of claim 48, further comprising means for receiving an overload indicator on the anchor carrier indicating overload of an uplink carrier regardless of carrier pairing, means for decoding the overload indicator, and means for reducing transmit power according to the decoded overload indicator.

55. The apparatus of claim 48, further comprising means for prioritizing power allocation among the plurality of uplink carriers based on a carrier priority of each of the plurality of uplink carriers.

56. The apparatus of claim 55, wherein an uplink anchor carrier has a higher carrier priority than other carriers in the plurality of uplink carriers.

57. The apparatus of claim 55, wherein the carrier priority of each of the plurality of uplink carriers corresponds to a priority of data transmitted on each of the plurality of uplink carriers.

58. The apparatus of claim 48, further comprising means for prioritizing power allocation among the plurality of uplink carriers based on a channel priority of each of the plurality of uplink carriers.

59. The apparatus of claim 58, further comprising means for autonomously prioritizing power allocation among the plurality of uplink carriers.

60. The apparatus of claim 58, wherein the channel priority for each of the plurality of uplink carriers is determined based on whether control data is transmitted across a channel of a corresponding one of the plurality of uplink carriers.

61. The apparatus of claim 55, further comprising means for prioritizing power allocation among the plurality of uplink carriers based on information received from a base station.