HK1137575B - Uplink power control for lte - Google Patents

Description

Uplink power control for LTE

Cross referencing

The present application claims benefit of U.S. provisional patent application No.60/889,931 entitled "A METHOD AND PROPPARTUS FOR POWER CONTROL USE A POWER CONTROL ON 14.2.2007. The above application is incorporated herein by reference in its entirety.

Technical Field

The following description relates generally to wireless communications, and more particularly to controlling Uplink (UL) power levels used by access terminals in a Long Term Evolution (LTE) based wireless communication system.

Background

Wireless communication systems are widely deployed to provide various types of communication such as voice and/or data that may be provided via such wireless communication systems. A typical wireless communication system or network may provide multi-user access to one or more shared resources (e.g., bandwidth, transmit power, etc.). For example, a system may use various multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing (OFDM), single carrier frequency division multiplexing (SC-FDM), and so on. Additionally, the system may conform to specifications such as third generation partnership project (3GPP), 3GPP Long Term Evolution (LTE), and the like.

In general, a wireless multiple-access communication system can simultaneously support communication for multiple access terminals. Each access terminal may communicate with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to access terminals, and the reverse link (or uplink) refers to the communication link from access terminals to base stations. The communication link may be established via a single-input single-output (SISO), multiple-input single-output (MISO), single-input multiple-output (SIMO), or multiple-input multiple-output (MIMO) system.

Wireless communication systems typically employ one or more base stations and sectors that provide coverage areas at the base stations. A typical sector can transmit multiple data streams for broadcast, multicast, and/or unicast services, wherein a data stream can be a stream of data that can be of independent interest to an access terminal. An access terminal within the sector coverage area can be employed to receive one, more than one, or all of the data streams carried by the composite stream. Likewise, an access terminal can transmit data to a base station or another access terminal. In situations where many access terminals transmitting signal data are close to each other, power control is important for communications on the uplink in order to produce sufficient signal-to-noise ratio (SNR) at different data rates and transmission bandwidths. When achieving the above goals, it is desirable to keep the overhead due to transmissions made for power adjustments to these access terminals as low as possible.

Disclosure of Invention

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

In accordance with one or more embodiments and corresponding disclosure thereof, various aspects are described in connection with facilitating use of aperiodic closed loop power control correction in a Long Term Evolution (LTE) based wireless communication environment. Aperiodic power control commands can be transmitted over the downlink to control and/or correct the uplink power level utilized by the access terminal. Transmission of aperiodic power control can be triggered by measurements (e.g., received power outside set limits.. or..) or by the opportunity to transmit control information from a sector to an access terminal on the downlink. The aperiodic power control command can include a single bit and/or a multi-bit correction. Further, upon receiving the aperiodic power control command, the access terminal can change an uplink power level for a subsequent uplink transmission based on the aperiodic power control command. In addition, the access terminal can adjust the uplink power level using periodic power control commands and an open loop power control mechanism regardless of whether aperiodic power control commands are received on the downlink at a given time.

According to related aspects, methodologies are described herein that facilitate generating power control commands in a wireless communication environment. The method can include receiving an uplink transmission from an access terminal. Further, the method can include determining whether to adjust an uplink power level used by the access terminal. In addition, the method can include transmitting power control commands to the access terminal using a layer 1/layer 2(L1/L2) control information channel for Downlink (DL) allocation and Uplink (UL) grants to change the uplink power level.

Another aspect relates to a wireless communications apparatus. The wireless communications apparatus can include a memory that retains instructions for: obtaining an uplink transmission sent from an access terminal at an uplink power level; interpreting whether to change the uplink power level; estimating an amount of adjustment to the uplink power level when the uplink power level is changed; and transmits power control commands to the access terminal via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants to change the uplink power level. Further, the wireless communications apparatus can include a processor coupled to the memory and configured to execute the instructions retained in the memory.

Another aspect relates to a wireless communications apparatus that enables generating power control commands for use by a wireless terminal in a wireless communication environment. The wireless communications apparatus can include means for obtaining an uplink transmission transmitted from an access terminal at an uplink power level. Further, the wireless communications apparatus can include means for estimating whether to change an uplink power level utilized by the access terminal. Further, the wireless communications apparatus can include means for transmitting a power control command via a layer 1/layer 2(L1/L2) control information channel utilized for Downlink (DL) allocation and Uplink (UL) grants, the power control command adjusting an uplink power level by a particular amount.

Another aspect relates to a machine-readable medium having stored thereon machine-executable instructions for: obtaining an uplink transmission sent from an access terminal at an uplink power level; estimating whether to change an uplink power level used by an access terminal; and transmits power control commands, which adjust the uplink power level by a certain amount, via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grant.

According to another aspect, an apparatus in a wireless communication system can include a processor, where the processor can be configured to receive an uplink transmission from an access terminal. Further, the processor can be configured to determine whether to adjust an uplink power level used by the access terminal. Further, the processor can be configured to transmit a power control command to the access terminal via a layer 1/layer 2(L1/L2) control information channel utilized for Downlink (DL) allocation and Uplink (UL) grants, the power control command changing an uplink power level when triggered by the measurement.

According to other aspects, methodologies are described herein that facilitate employing power control commands in a wireless communication environment. The method may include transmitting data on an uplink at a power level. Further, the method may include receiving the power control command via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants. The method may also include changing the power level based on the power control command. Further, the method may include transmitting data on the uplink at the altered power level.

Another aspect relates to a wireless communications apparatus that can include a memory that retains instructions for: transmitting data on an uplink at a power level; obtaining power control commands via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants; and adjusting the power level for subsequent data transmissions based on the power control command. Further, the wireless communications apparatus can include a processor coupled to the memory and configured to execute the instructions retained in the memory.

Another aspect relates to a wireless communications apparatus that enables employing power control commands in a wireless communication environment. The wireless communications apparatus can include means for transmitting data on an uplink at a power level. Further, the wireless communications apparatus can include means for obtaining power control commands via a layer 1/layer 2(L1/L2) control information channel utilized for Downlink (DL) allocation and Uplink (UL) grants. Further, the wireless communications apparatus can include means for varying a power level of a subsequent data transmission as a function of the power control command.

Another aspect relates to a machine-readable medium having stored thereon machine-executable instructions for: transmitting data on an uplink at a power level; obtaining power control commands via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants; and changes the power level for subsequent data transmissions in accordance with the power control commands.

According to another aspect, an apparatus in a wireless communication system can include a processor, where the processor can be configured to transmit data on an uplink at a power level. Further, the processor may be configured to receive power control commands via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants. Further, the processor may be configured to vary the power level based on the power control command. In addition, the processor may be configured to transmit data on the uplink at the altered power level.

To the accomplishment of the foregoing and related ends, the one or more embodiments 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 aspects of the one or more embodiments. These aspects are indicative, however, of but a few of the various ways in which the principles of various embodiments may be employed and the described embodiments are intended to include all such aspects and their equivalents.

Drawings

Fig. 1 is an illustration of a wireless communication system in accordance with various aspects set forth herein;

FIG. 2 is an illustration of an example system that controls uplink power levels utilized by access terminals in an LTE based wireless communication environment;

FIG. 3 is an illustration of an exemplary system that periodically corrects for uplink power levels used by an access terminal;

fig. 4 is an illustration of an example system that facilitates aperiodically communicating power control commands to access terminals in an LTE based wireless communication environment;

fig. 5 is an illustration of an exemplary system that groups access terminals for transmitting power control commands on the downlink;

fig. 6 is an illustration of an exemplary transmission structure for transmitting power control commands to a group of access terminals;

fig. 7 is an exemplary timing diagram of a periodic uplink power control procedure for LTE;

fig. 8 is an exemplary timing diagram of an aperiodic uplink power control procedure for LTE;

FIG. 9 is an illustration of an example methodology that facilitates generating power control commands in a wireless communication environment;

FIG. 10 is an illustration of an example methodology that facilitates employing power control commands in a wireless communication environment;

fig. 11 is an illustration of an example access terminal that facilitates utilizing aperiodic power control commands in an LTE based wireless communication system;

FIG. 12 is an illustration of an example system that facilitates generating aperiodic power control command in an LTE based wireless communication system;

FIG. 13 is an illustration of an exemplary wireless network environment that can be employed in conjunction with the various systems and methods described herein;

FIG. 14 is an illustration of an exemplary system that enables generating power control commands utilized by access terminals in a wireless communication environment;

fig. 15 is an illustration of an example system that enables utilizing power control commands in a wireless communication environment.

Detailed Description

Various embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. 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 embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.

As used in this application, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either 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 can reside within a process and/or thread of execution and a component can 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. For example, in accordance with a signal having one or more data packets (e.g., 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 via the signal), the components may communicate by way of local and/or remote processes.

Moreover, various embodiments are described herein in connection with an access terminal. An access terminal can be called a system, subscriber unit, subscriber station, mobile station, handset, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent, user device, or User Equipment (UE). An access terminal may be a cellular 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 embodiments may be described herein in connection with a base station. A base station may be utilized for communicating with access terminal(s) and may also be referred to as an access point, node B, e, node b (enb), or some other terminology.

Moreover, various aspects or features described herein may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques. The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., Compact Disk (CD), Digital Versatile Disk (DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card, stick, key drive, etc.). In addition, various storage media described herein can represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" can include, without being limited to, wireless channels and various other media capable of storing, containing, and/or carrying instruction(s) and/or data.

Referring now to fig. 1, a wireless communication system 100 is illustrated in accordance with various embodiments presented herein. System 100 comprises a base station 102, which base station 102 can comprise multiple antenna groups. For example, one antenna group can include antennas 104 and 106, another group can include antennas 108 and 110, and an additional group can include antennas 112 and 114. Two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each group. Additionally, base station 102 can comprise a transmitter chain and a receiver chain, each of which can in turn comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by one skilled in the art.

The respective sectors of base station 102 can communicate with one or more access terminals, such as access terminal 116 and access terminal 122, however, it will be appreciated that base station 102 can communicate with virtually any number of access terminals similar to access terminals 116 and 122. For example, the access terminals 116 and 122 can be cellular phones, smart phones, laptops, handheld communication devices, handheld computing devices, satellite radios, global positioning systems, PDAs, and/or any other suitable device for communicating over the wireless communication system 100. As depicted, access terminal 116 is in communication with antennas 112 and 114, where antennas 112 and 114 transmit information to access terminal 116 over forward link 118 and receive information from access terminal 116 over reverse link 120. In addition, access terminal 122 is in communication with antennas 104 and 106, where antennas 104 and 106 transmit information to access terminal 122 over forward link 124 and receive information from access terminal 122 over reverse link 126. In a Frequency Division Duplex (FDD) system, forward link 118 can utilize a different frequency band than that used by reverse link 120, and forward link 124 can employ a different frequency band than that employed by reverse link 126, for example. Further, in a Time Division Duplex (TDD) system, forward link 118 and reverse link 120 can utilize a common frequency band and forward link 124 and reverse link 126 can utilize a common frequency band.

Each group of antennas and/or the area in which each group of antennas is designated to communicate can be referred to as a sector of base station 102 or a cell of an eNB. For example, antenna groups can be designed to communicate to access terminals in a sector of the areas covered by base station 102. In communication over forward links 118 and 124, the transmitting antennas of base station 102 can utilize beamforming in order to improve signal-to-noise ratio of forward links 118 and 124 for access terminals 116 and 122. Also, when base station 102 utilizes beamforming to transmit to access terminals 116 and 122 scattered randomly through an associated coverage, access terminals in neighboring cells can be subject to less interference as compared to a base station transmitting through a single antenna to all its access terminals.

For example, system 100 may be a Long Term Evolution (LTE) based system. In such a system 100, respective sectors of a base station 102 can control the uplink power levels used by access terminals 116 and 122. Thus, system 100 may provide Uplink (UL) power control that results in compensation for path loss and shadowing (e.g., path loss and shadowing may change slowly over time), as well as compensation for time-varying interference from neighboring cells (e.g., since system 100 may be an LTE-based system that employs frequency reuse rate 1). Moreover, system 100 can mitigate large variations (variations) in received power obtained at base station 102 among multiple users (e.g., because multiple users can be multiplexed within a common frequency band). In addition, system 100 can compensate for multipath fading variation at sufficiently low speeds. For example, for 3km/h, the channel coherence time at different carrier frequencies may be as follows: a 900MHz carrier frequency may have a coherence time of 400ms, a 2GHz carrier frequency may have a coherence time of 180ms, and a 3GHz carrier frequency may have a coherence time of 120 ms. Thus, depending on the reaction time and periodicity of the adjustment, fast fading effects can be corrected with low doppler frequencies.

System 100 may use uplink power control that combines an open-loop power control mechanism and a closed-loop power control mechanism. According to an example, each access terminal 116, 122 can utilize open loop power control to set a power level for a first preamble of a Random Access Channel (RACH) communication. For the first preamble of the RACH, each access terminal 116, 122 may have Downlink (DL) communication obtained from base station 102, and the open-loop mechanism may enable each access terminal 116, 122 to select an uplink transmit power level that is inversely proportional to a receive power level for the obtained downlink communication. In this way, the access terminals 116, 122 can utilize knowledge of the downlink for uplink transmissions. By means of instantaneous power adjustment, the open loop mechanism may allow a very fast adaptation to drastic changes in radio conditions (e.g. depending on the received power filtering). Furthermore, the open loop mechanism may continue to operate outside of the RACH processing, as compared to conventional techniques that are commonly used. Once the random access procedure is successful, the system 100 may utilize a closed-loop mechanism. For example, closed loop techniques can be used when periodic uplink resources have been allocated to the access terminals 116, 122 (e.g., the periodic uplink resources can be Physical Uplink Control Channel (PUCCH) or Sounding Reference Signal (SRS) resources). Further, respective sectors in the base station 102 (and/or network) can control uplink transmit power used by the access terminals 116, 122 based on closed loop control.

The closed loop mechanism used by the system 100 may be periodic, aperiodic, or a combination of both. The periodic closed loop correction can be periodically transmitted by the respective sector in the base station 102 to the access terminals 116, 122 (e.g., once every 0.5ms, 1ms, 2ms, 4ms … …). For example, the periodicity may depend on the periodicity of the uplink transmission. Further, the periodic corrections may be single bit corrections (e.g., up/down, ± 1dB, … …) and/or multi-bit corrections (e.g., ± 1dB, ± 2dB, ± 3dB, ± 4dB, … …). In this way, the power control step size and periodicity of the corrections can determine the maximum rate of uplink power change that a corresponding sector within base station 102 (and/or the network) can control. According to another example, aperiodic corrections can be sent from respective sectors in base station 102 to respective access terminals 116, 122 as needed. According to this example, these corrections can be sent aperiodically when triggered by network measurements (e.g., Received (RX) power outside set limits, opportunity to send control information to a given access terminal, … …). Further, the aperiodic corrections can be single-bit and/or multi-bit (e.g., corrections can be multi-bit since a significant portion of the overhead associated with the aperiodic corrections can relate to correction scheduling rather than correction size). According to another example, respective sectors within base station 102 can transmit aperiodic corrections to access terminals 116, 122 in addition to periodic corrections to minimize overhead incurred by transmission of such power adjustments.

Turning now to fig. 2, illustrated is a system 200 that controls uplink power levels utilized by access terminals in an LTE based wireless communication environment. System 200 includes sectors within a base station 202 that can communicate with substantially any number of access terminals (not shown). Further, a sector within base station 202 can include a received power monitor 204 that estimates a power level associated with an uplink signal obtained from an access terminal. Further, a sector within base station 202 can include an Uplink (UL) power adjuster 206 that utilizes the analyzed power level to generate commands to vary access terminal power levels.

Various Physical (PHY) channels 208 may be leveraged for communication between base station 202 and access terminals; these physical channels 208 may include downlink physical channels and uplink physical channels. Examples of the downlink physical channel include a Physical Downlink Control Channel (PDCCH), a Physical Downlink Shared Channel (PDSCH), and a Common Power Control Channel (CPCCH). The PDCCH is a DL layer 1/layer 2(L1/L2) control channel (e.g., allocating PHY layer resources for DL or UL transmissions) that has a capacity of approximately 30-60 bits and is protected by a Cyclic Redundancy Check (CRC). The PDCCH may carry uplink grants (grant) and downlink allocations. PDSCH is DL shared data channel; the PDSCH may be a DL data channel shared among different users. The CPCCH is transmitted on the DL for UL power control for multiple access terminals. The corrections sent on the CPCCH may be single-bit or multi-bit. Furthermore, the CPCCH may be a specific instance of the PDCCH. Examples of the uplink physical channel include a Physical Uplink Control Channel (PUCCH), a Physical Uplink Shared Channel (PUSCH), a Sounding Reference Signal (SRS), and a Random Access Channel (RACH). The PUCCH includes reports of Channel Quality Indicator (CQI) channels, ACK channels, and UL requests. PUSCH is a UL shared data channel. The SRS may have no information and may enable sounding of the channel on the UL to allow sampling of the channel over part or all of the system bandwidth. It is to be appreciated that the claimed subject matter is not limited to these exemplary physical channels 208.

Receive power monitor 204 and UL power adjuster 206 can provide closed loop power control for uplink transmissions by the access terminal. Operation on an LTE system may require transmission over a bandwidth that may be significantly less than the overall bandwidth of system 200 at a given time. Each access terminal may transmit over a small portion of the overall bandwidth of system 200 at a given time. In addition, the access terminal may use frequency hopping; thus, difficulties can be encountered when a corresponding sector within base station 202 attempts to estimate an adjustment to be made to the uplink power level of an access terminal. Thus, the proper closed-loop power control mechanism provided by received power monitor 204 and UL power adjuster 206 constructs a wideband received power estimate from transmissions over possibly multiple instants and over possibly multiple UL PHY channels, which can provide proper correction for path loss and shadowing effects at any time regardless of access terminal transmission bandwidth.

Received power monitor 204 constructs a wideband received power estimate from the channel samples based on the access terminal transmissions in various ways. For example, received power monitor 204 may use PUSCH for sampling. According to this example, the transmission bandwidth of PUSCH is located on a given slot. Frequency diversity scheduling may apply a pseudo-random frequency hopping pattern to the transmission bandwidth at the slot boundaries and possibly to retransmissions in order to exploit frequency diversity. PUSCH transmissions with frequency selective scheduling do not apply a frequency hopping pattern to the transmitted data and, therefore, may require a longer time to sample the channels on all (or most) frequencies. Furthermore, frequency selective scheduling may balance the transmission of SRS or PUCCH. Frequency selective scheduling is a scheduling strategy that utilizes channel selectivity; for example, frequency selective scheduling attempts to limit transmissions to the best subbands. The scheduling policy is related to low mobility access terminals. Furthermore, these transmissions typically do not include frequency hopping techniques. Frequency diversity scheduling is a completely different scheduling strategy that uses the entire system bandwidth (e.g., modulo … … the minimum transmit bandwidth capacity) to naturally achieve frequency diversity. The transmissions associated with frequency diversity scheduling may be associated with frequency hopping. Furthermore, frequency hopping may include changing the transmit frequency of the waveform in a pseudo-random manner to take advantage of frequency diversity from a channel as well as interference perspective.

According to another example, received power monitor 204 may sample the UL channel using PUCCH and, therefore, construct a wideband received power estimate. The transmission bandwidth of the PUCCH can also be located over a given slot, hopping over the slot boundaries of each Transmission Time Interval (TTI). The occupied bandwidth may depend on whether there is a PUSCH transmission on a particular TTI. When the PUSCH is transmitted over a given TTI, the control information to be transmitted on the PUCCH may be transmitted in-band with the remainder of the data transmission on the PUSCH (e.g., to preserve the single carrier properties of the UL waveform). When PUSCH is not transmitted over a particular TTI, PUCCH may be transmitted on the partial band set aside for PUCCH transmission at the edge of the system bandwidth.

According to another illustration, received power monitor 204 can utilize SRS transmissions to sample a channel and construct a wideband received power estimate. The transmission band of the SRS may be (in time) substantially equal to the entire system band (or minimum access terminal transmission bandwidth capacity). At a given SC-FDMA symbol (e.g., an SC-FDMA symbol is the smallest unit of transmission on the UL of LTE), the transmission may be localized (e.g., across a contiguous set of subcarriers that hop in time) or distributed (e.g., across the entire system bandwidth or a portion of the entire system bandwidth, which may or may not hop … …).

Received power monitor 204 constructs a wideband received power estimate from samples of the channel over the entire system bandwidth. However, the time interval at which receive power monitor 204 constructs a wideband receive power estimate from the UL channel samples may vary depending on the manner in which the channel is sampled and/or whether frequency hopping is applied to the transmission.

PUCCH transmission when no UL data is present occurs at the edge of the system band. PUCCH transmission in the presence of UL data may be located within the same frequency band as data transmission on PUSCH. Furthermore, in order to utilize UL frequency selective scheduling, PUSCH transmission may not change transmission frequency or hop at all, however, to enable frequency selective scheduling, SRS may be balanced for FDD/TDD systems. Further, frequency hopping is applied to transmission when the PUSCH uses frequency diversity scheduling.

Further, based on the channel sampling accomplished by received power monitor 204, UL power adjuster 206 can generate commands that can change the UL power level used by a particular access terminal. The command may be a single bit correction (e.g., up/down, ± 1dB, … …) and/or a multi-bit correction (e.g., ± 1dB, ± 2dB, ± 3dB, ± 4dB, … …). Further, UL power adjuster 206 (and/or a sector within respective base station 202) can transmit the generated command to an access terminal for which the command is intended.

Further, each access terminal may be associated with a particular state at a given time. Examples of access terminal states include LTE _ IDLE, LTE _ ACTIVE, and LTE _ ACTIVE _ CPC. It is to be appreciated, however, that the claimed subject matter is not limited to these illustrative states.

LTE _ IDLE is an access terminal state where the access terminal does not have a unique cell ID. When in the LTE _ IDLE state, the access terminal may have no connection to the base station 202. Further, the transition from LTE _ IDLE state to LTE _ ACTIVE state may be accomplished via using RACH.

LTE ACTIVE is an access terminal state where the access terminal has a unique cell ID. Further, while in the LTE ACTIVE state, the access terminal may actively transmit data via the uplink and/or downlink. The access terminal in this state has UL dedicated resources (e.g., periodically transmitted CQI, SRS … …). According to one example, an access terminal in LTE ACTIVE state can employ a discontinuous transmission/discontinuous reception (DTX/DRX) procedure with a periodicity that is not expected to be much longer than approximately 20ms or 40 ms. An access terminal in this state starts PUSCH transmission either as a direct response to DL behavior (e.g., UL grant in-band with DL data or possibly available through PDCCH) or by sending a UL request on PUCCH. Further, the user in this state may be an access terminal with active exchange of UL/DL data taking place, or an access terminal running a high service level (GoS) application, such as voice over internet protocol (VoIP) … ….

LTE _ ACTIVE _ CPC (continuous packet connectivity) is a sub-state of LTE _ ACTIVE, where access terminals retain their unique cell ID, but have released UL dedicated resources. Utilizing LTE _ ACTIVE _ CPC enables extended battery life. An access terminal in this sub-state begins transmission in response to DL behavior (e.g., UL grant, possibly available in-band with DL data or through PDCCH), or by sending a UL request on RACH. The initial transmit power may be based on an open loop mechanism (e.g., as a response to DL behavior) or may be based on the last successful preamble (e.g., RACH).

Referring to fig. 3, illustrated is a system 300 that periodically corrects for uplink power levels used by an access terminal. System 300 includes a base station 202 that communicates with an access terminal 302 (and/or any number of disparate access terminals (not shown)). Access terminal 302 includes UL power manager 304, UL power manager 304 further including UL power initializer 306. In addition, access terminal 302 includes a UL periodic transmitter 308. Base station 202 also includes a received power monitor 204 and an UL power adjuster 206; UL power adjuster 206 also includes a periodicity corrector 310.

Periodicity corrector 310 generates periodic power control commands (e.g., periodic Transmit Power Control (TPC) commands, periodicity correction, … …) to be transmitted to access terminal 302. Moreover, periodicity corrector 310 can send periodic power control commands to access terminal 302 (and/or any disparate access terminal) at any periodicity (e.g., 0.5ms, 1ms, 2ms, 4ms … …); however, it is contemplated that UL power adjuster 206 and/or base station 202 can transmit such periodic power control commands. Furthermore, periodic corrector 310 may produce single bit corrections (e.g., up/down, ± 1dB … …) and/or multi-bit corrections (e.g., ± 1dB, ± 2dB, ± 3dB, ± 4dB … …). For example, if periodic corrections are sent from periodic corrector 310 at a higher frequency, then single-bit corrections are more likely to be used, and vice versa.

UL power manager 304 controls the uplink power level used by access terminal 302 for uplink transmissions. UL power manager 304 can receive periodic power control commands from base station 202 and change the uplink power level used for transmission based on the obtained commands. According to another illustration, UL power initializer 306 can set an initial uplink transmit power. For example, UL power initializer 306 may use an open loop mechanism to determine the initial uplink transmit power based on downlink behavior. Additionally or alternatively, UL power initializer 306 can allocate an initial uplink power level to a power level associated with a previous (e.g., previous … …) successful preamble (e.g., RACH).

UL periodic transmitter 308 may send periodic transmissions on the uplink to base station 202. For example, UL periodic transmitter 308 can operate when access terminal 302 is in LTE ACTIVE state. Further, the periodic transmission transmitted by UL periodic transmitter 308 can be a set of SRS transmissions; however, it is to be appreciated that the claimed subject matter is not so limited and any type of periodic uplink transmission (e.g., periodic CQI transmission, periodic PUCCH transmission … …) may be used. As such, since the SRS transmission may be a sounding signal, UL periodic transmitter 308 may transmit the SRS transmission on the uplink to sound the channel over the entire system bandwidth; thus, at the same time as uplink frequency selective scheduling is performed, sounding signals can be used to calculate closed loop corrections for UL power control. In conjunction with sampling the channel, the received power monitor 204 of the base station 202 can receive and/or use the transmission sent by the UL periodic transmitter 308. Further, UL power adjuster 206 and/or periodicity corrector 310 may generate a command corresponding to the sample.

According to one illustrative example, the periodicity of the UL transmission sent by UL periodic transmitter 308 of access terminal 302 can be correlated to the DLTPC command transmission period used by periodicity corrector 310 for access terminal 302; thus, DL TPC commands may be sent with disparate transmission periods for access terminals with different UL transmission periodicities. Further, the periodicity of the UL transmission can be related to the number of bits allocated for access terminal power adjustments generated by periodicity corrector 310 for a particular access terminal (e.g., access terminal 302 … …). For example, a mapping between the number of bits allocated for uplink power control correction and the uplink periodic transmission rate (e.g., SRS transmission rate, PUCCH transmission rate … …) may be predetermined. According to this example, an uplink periodic transmission rate of 200Hz may be mapped to 1 bit, a rate of 100Hz may be mapped to 1 bit, a rate of 50Hz may be mapped to 2 bits, a rate of 25Hz may be mapped to 2 bits, and a rate of 0Hz may be mapped to x > 2 bits. According to the foregoing example, the number of bits allocated to power adjustments at the access terminal becomes larger as the uplink periodic transmission rate decreases. At the limit of the 0Hz uplink periodic transmission rate (e.g., no transmission of SRS, PUCCH … …), the power adjustment may be x > 2 bits, which may be the case for open loop transmission with closed loop adjustment as needed.

Periodic corrector 310 can send corrections on a periodic basis to substantially all users associated with base station 202 in the LTE ACTIVE state. Pursuant to an example, users to which the periodicity corrector 310 sends commands can be grouped based on, for example, GoS requirements, DRX/DTX cycles and offsets, and so forth. The periodicity corrector 310 may transmit power control commands for a user group on a specific instance of the PDCCH, which may be denoted as CPCCH or TPC-PDCCH. According to another illustration, the periodicity corrector 310 may use in-band signaling for a group of users, where the size of the group of users may be greater than or equal to 1. The overhead associated with periodic correction can be based on the number of bits required for correction and the associated control (if any) required to convey information to the associated access terminal.

For the periodic corrector 310 to Transmit Power Control (TPC) commands on the PDCCH, a 32-bit payload and an 8-bit CRC may be used. For example, 32 single bit TPC commands in a 1ms time interval may be used for 1 PDCCH occasion. Thus, assuming FDD is used, 320 users in LTE _ ACTIVE state can be supported at 100Hz using a single PDCCH per TTI. Thus, a single bit correction can be provided every 10ms, which can allow a correction of 100 dB/s. According to another example, 16 two-bit TPC commands may be used within a 1ms time interval. Thus, assuming FDD is used, 320 users in LTE _ ACTIVE state can be supported at 50Hz using a single PDCCH per TTI. Thus, a two-bit correction every 20ms allows a correction of 100 dB/s.

Turning now to fig. 4, illustrated is a system 400 that facilitates communicating power control commands aperiodically to access terminals in an LTE based wireless communication environment. System 400 includes a base station 202 that communicates with an access terminal 302 (and/or any number of disparate access terminals (not shown)). Base station 202 includes a received power monitor 204 and an UL power adjuster 206, and UL power adjuster 206 further includes an aperiodic corrector 402. In addition, access terminal 302 includes UL power manager 304, UL power manager 304 further including aperiodic command receiver 404.

Aperiodic corrector 402 can generate power control commands directed to access terminal 302 as needed. For example, aperiodic corrector 402 can occasionally transmit when triggered by a measurement (e.g., a measurement of a condition identified with data from received power monitor 204, such as received power outside a set boundary). Aperiodic corrector 402 can determine that the uplink power level of access terminal 302 deviates from a target at a particular time; thus, in response, aperiodic corrector 402 can send a command to adjust the power level. Further, aperiodic corrector 402 can produce single-bit corrections (e.g., up/down, ± 1dB … …) and/or multi-bit corrections (e.g., ± 1dB, ± 2dB, ± 3dB, ± 4dB … …).

Aperiodic command receiver 404 can obtain corrections transmitted by aperiodic corrector 402 (and/or UL power adjuster 206 and/or, in general, a corresponding sector within base station 202). For example, the aperiodic command receiver 404 can interpret that a particular correction sent by a corresponding sector in the base station 202 is intended for the access terminal 302. Further, based on the obtained correction, aperiodic command receiver 404 and/or UL power manager 304 can change the uplink power level utilized by access terminal 302.

The aperiodic correction for the uplink power level for access terminal 302 generated by aperiodic corrector 402 can be trigger-based. Thus, aperiodic corrections can be associated with greater overhead than periodic corrections due to their unicast nature. In addition, according to one example using multi-bit aperiodic corrections, these corrections can be mapped to specific instances of PDCCH (e.g., in which case the power correction can be transmitted as part of a DL assignment or UL grant) or PDCCH/PDSCH pair (e.g., in which case the power correction can be transmitted independently or in-band with other data transmissions).

Referring now to fig. 5, illustrated is a system 500 that groups a plurality of access terminals for transmitting power control commands on the downlink. System 500 includes a base station 202 in communication with an access terminal 1502, access terminals 2504, … …, and an access terminal N506, where N can be any integer. Each access terminal 502-506 may further include a respective UL power manager (e.g., access terminal 1502 includes UL power manager 1508, access terminal 2504 includes UL power managers 2510, … …, and access terminal N506 includes UL power manager N512). Further, the respective sectors in base station 202 can include received power monitor 204, UL power adjuster 206, and access terminal grouper 514, access terminal grouper 514 grouping subsets of access terminals 502 and 506 for transmitting power control commands on the downlink.

AT grouper 514 can group access terminals 502 and 506 based on various factors. For example, AT grouper 514 can assign one or more access terminals 502 and 506 to a group based on DRX cycle and phase. Pursuant to another illustration, AT grouper 514 can assign access terminals 502-506 to groups based upon uplink periodic transmission rates (e.g., SRS transmission rate, PUCCH transmission time interval … …) utilized by access terminals 502-506. By combining the various subsets of access terminals 502-506 into different groups, UL power adjuster 206 can more efficiently transmit power control commands on the DL over the PDCCH (or CPCCH) (e.g., by sending power control commands in a common message for multiple access terminals grouped together). By way of example, AT grouper 514 may form a group for use with periodic uplink power control; however, claimed subject matter is not so limited.

According to one illustration, access terminal 1502 can employ a transmission rate of 200Hz for SRS transmission, access terminal 2504 can employ a transmission rate of 50Hz for SRS transmission, and access terminal N506 can employ a transmission rate of 100Hz for SRS transmission. AT grouper 514 may identify these various transmission rates (e.g., using signals obtained via received power monitor 204, etc.). AT grouper 514 can then assign access terminal 1502 and access terminal N506 (along with any other access terminals using 100Hz or 200Hz transmission rates) to group a. AT grouper 514 can also assign access terminal 2504 (and any disparate access terminals using 25Hz or 50Hz transmission rates) to group B. It will be appreciated, however, that the claimed subject matter is not limited to the foregoing illustrative examples. Further, AT grouper 514 can assign a group ID to each group (e.g., for use on the PDCCH or CPCCH). Once access terminals 502 and 506 are assigned to the various groups, the commands sent by UL power adjuster 206 may use downlink resources corresponding to the particular group associated with the intended receiving access terminal. For example, AT grouper 514 and UL power adjuster 206 can operate cooperatively to transmit TPC commands to multiple access terminals 502 in each PDCCH transmission 506. In addition, each UL power manager 508 and 512 can identify appropriate PDCCH transmissions for listening to obtain TPC commands directed thereto (e.g., based on the corresponding group ID … …).

Turning to fig. 6, illustrated is an exemplary transmission structure for transmitting power control commands to a group of access terminals. For example, the transmission structure may be used for PDCCH transmission. Two exemplary transport structures (e.g., transport structure 600 and transport structure 602) are described; however, it is contemplated that claimed subject matter is not limited to these examples. Transmission structures 600 and 602 may reduce overhead by grouping power control commands for multiple users into each PDCCH transmission. As illustrated, transmission structure 600 groups power control commands for users in group a onto a first PDCCH transmission and groups power control commands for users in group B onto a second PDCCH transmission. In addition, both the first and second PDCCH transmissions include a Cyclic Redundancy Check (CRC). In addition, transmission structure 602 incorporates power control commands for users in groups a and B on a common PDCCH transmission. By way of illustration, for transmission structure 602, power control commands for users in group a may be included in a first segment of a common PDCCH transmission and power control commands for users in group B may be included in a second segment of the common PDCCH transmission.

Referring to fig. 7, illustrated is an exemplary timing diagram 700 for a periodic uplink power control procedure for LTE. At 702, a power control procedure for an access terminal in an LTE ACTIVE state is illustrated. In this state, the access terminal sends periodic SRS transmissions to the base station, and the base station replies to the periodic SRS transmissions with periodic TPC commands. As shown in the illustrated example, the transmit power of the access terminal is corrected by a single TPC bit sent periodically on the downlink. It will be noted that periodic SRS transmission may be replaced by periodic CQI transmission, periodic PUCCH transmission, or the like. Since periodic CQI transmissions or periodic PUCCH transmissions may not span the entire system bandwidth, these transmissions may be inefficient from a channel sounding standpoint; however, for closed loop correction, these transmissions may be balanced based on UL measurements at the base station.

At 704, inactivity periods for the access terminal are described. After an inactivity period (e.g., predetermined or using a threshold period), the access terminal transitions to the LTE _ ACTIVE _ CPC sub-state. In this sub-state, the PHY UL resources are deallocated from the access terminal; therefore, when recovering UL transmission, it is not possible to use closed loop power control.

At 706, the access terminal resumes uplink transmission. The RACH is utilized to recover the uplink transmission using an open loop estimate. According to an example, the open loop estimate can be modified by a forgetting factor based on the last transmission power, if deemed beneficial. In response to the RACH transmitted by the access terminal, the base station may transmit an in-band power adjustment (e.g., an x-bit power adjustment, where x may be substantially any integer) for the access terminal.

At 708, the identity of the access terminal may be verified through a RACH procedure. Further, PHY UL resource reallocation may be done at 708 (e.g., along with SRS configuration).

At 710, the access terminal is in LTE _ ACTIVE state. Thus, the access terminal resumes periodic transmission of the SRS. As noted, the periodicity of the periodic SRS transmission at 710 is different from the periodicity of the periodic SRS transmission at 702; however, claimed subject matter is not so limited. In response to the periodic SRS transmission, the base station transmits a TPC command, in which case the TPC command occupies 2 bits (e.g., ± 1dB, ± 2 dB). Further, although not illustrated, the access terminal transmission may continue with open loop correction determined from the received power level at the access terminal. Thus, closed loop correction may not be included and/or may be on top of an open loop correction determined from a change in received power at the access terminal.

Turning now to fig. 8, illustrated is an exemplary timing diagram 780 of an aperiodic uplink power control procedure for LTE. Illustrated is a power control procedure for an access terminal in an LTE ACTIVE state. The timing diagram 800 may have no periodic uplink transmissions. Further, a power correction can be transmitted from the base station to the access terminal based on the power received on the PUSCH. The base station evaluates the PUSCH transmission to determine whether to power adjust. If the base station deems a power adjustment is needed by evaluating a particular PUSCH transmission, the aperiodic power adjustment can depend on where the base station sends the message (e.g., TPC command on UL grant) to the access terminal. When the base station determines that such power adjustment is not necessary for a given PUSCH transmission at a particular time, then the base station need not send TPC commands in response to the given PUSCH transmission at that time (rather, an ACK … … may be sent, for example, in response to the given PUSCH transmission). Furthermore, regardless of whether the access terminal gets TPC commands at a given time, the access terminal can always rely on open loop mechanism based correction. Furthermore, the corrections sent by the base station may be single bit corrections and/or multi-bit corrections.

It will be appreciated that a similar scheme may be used with periodic UL transmissions, where corrections may be sent on the DL as needed. In this way, the access terminal can periodically transmit an SRS transmission on the uplink, which can be estimated by the base station to determine the power adjustment to be performed. Thereafter, upon determining that power adjustment is needed at a particular time, the base station can send TPC commands to the access terminal on the downlink (e.g., aperiodic downlink transmission of power control commands).

The uplink power control procedure described in fig. 7 and 8 includes a number of common aspects. That is, the concept of delta PSD (delta power spectral density) for UL data transmission can be used for periodic and aperiodic uplink power control. The delta PSD may provide the maximum transmit power allowed for a given user in order to minimize the impact on neighboring cells. The delta PSD may evolve over time with, for example, load indicators from neighboring cells, channel conditions, etc. Further, when possible, the Δ PSD can be reported to the access terminal (e.g., in-band). In an LTE system, the network may select which MCS/Max data-to-pilot power ratio the access terminal is allowed to transmit using. However, the initial Δ PSD may be based on the MCS in the UL grant (e.g., the relationship between the UL grant and the initial Δ PSD may be formula-based). Furthermore, most of the foregoing relates to intra-cellular power control. Other mechanisms for intra-cell power control (e.g., load control) may be complementary to those described herein.

According to another illustration, the periodic and aperiodic uplink power control procedures can operate in combination. According to this illustrative example, periodic updates may also be used on an aperiodic update basis. If there are scheduled PUSCH transmissions, these PUSCH transmissions may require corresponding PDCCH transmissions with UL grants, and therefore, power control commands may be sent with the UL grant in the PDCCH. For example, if PDCCH is not available for persistent UL transmission (e.g., no UL grant is needed due to the PHY resources being configured by higher layers), then power control commands may be sent on TPC-PDDCH 1. Meanwhile, if there is a scheduled PDSCH on the DL, power control of the PUCCH (e.g., CQI and ACK/NAK) may become more important. In this case, a power control command for the PUCCH may be transmitted on the PDCCH together with the DL assignment. For DL transmissions with no associated control or for the case of no DL data behavior, the PUCCH may be power controlled using periodic transmissions on TPC-DPCCH 2. Thus, power control commands may be transmitted when needed (e.g., aperiodically) while using available resources (e.g., using PDCCH with UL grant for PUSCH, PDCCH with DL assignment for PUCCH, periodic TPC commands on TPC-PDCCH, which may be related to PUCCH and persistently scheduled PUSCH, … …).

Referring to fig. 9-10, methodologies relating to controlling uplink power using corrections in a wireless communication environment are illustrated. While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with one or more embodiments.

Referring to fig. 9, illustrated is a methodology 900 that facilitates generating power control commands in a wireless communication environment. At 902, an uplink transmission can be received from an access terminal. For example, the uplink transmission may be a Physical Uplink Shared Channel (PUSCH) transmission. According to another illustration, the uplink transmission can be from a set of periodic uplink transmissions sent by the access terminal; likewise, the periodic uplink transmission may be a Sounding Reference Signal (SRS) transmission, a quality channel indicator (CQI) transmission, a Physical Uplink Control Channel (PUCCH) transmission, or the like. At 904, a determination can be made whether to adjust an uplink power level used by the access terminal. The uplink power level being analyzed is related to the received uplink transmission. According to an example, the uplink power level may be compared to a target value and if the difference exceeds a threshold, an adjustment may be triggered; otherwise, if the difference is less than the threshold, then no adjustment is needed at this time. In addition, an amount of adjustment to the access terminal uplink power level can be determined. In accordance with another illustration, the quality metric can be used to determine whether to adjust the uplink power level based on a constructed wideband received power or signal-to-noise ratio (SNR) estimate constructed from a set of received uplink transmissions transmitted on the uplink by the access terminal (e.g., the set of received uplink transmissions can include periodically transmitted signals such as PUCCH, SRS, aperiodically transmitted signals such as PUSCH, etc.). If it is determined at 904 that no adjustment to the uplink power level is required, methodology 900 ends. If it is determined at 904 that an adjustment should be made to the uplink power level, methodology 900 continues at 906. At 906, power control commands can be sent to the access terminal using a layer 1/layer 2(L1/L2) control information channel for Downlink (DL) allocation and Uplink (UL) grants to change the uplink power level. For example, transmission of the power control command may be triggered by a measurement (e.g., a measurement of a received power level outside a set boundary) or an opportunity to send the power control command (e.g., because of transmission of a UL grant). Based on the determination at 904, power control commands can be sent as needed. In this way, power control commands can be sent on available channels (as opposed to fixed preset locations and channels) when needed. For example, power control commands may be sent on a subset of time, on PDCCH (when available) with DL allocations or UL grants; and may transmit power control commands on the TPC-PDCCH (when available) at other times. Each power control command may be a single bit correction (e.g., up/down, ± 1dB … …) and/or a multi-bit correction (e.g., 0dB, ± 1dB, ± 2dB, ± 3dB, ± 4dB … …). Furthermore, the power control commands may be mapped to specific instances of a Physical Downlink Control Channel (PDCCH) or PDCCH/PDSCH (physical downlink shared channel) pair. Further, power control commands may be sent independently or in-band with other data transmissions. In addition, the power control commands may be transmitted via unicast transmission, for example.

The power control commands may be transmitted in multiple locations. For example, the power control command may be transmitted on the PDCCH together with a DL assignment or UL grant. For example, the power control command may be transmitted via the PDCCH together with a DL assignment, which may be related to the PUCCH. Further, the power control command may be transmitted via the PDCCH together with a UL grant, which may be related to the PUSCH. According to another illustration, the power control commands can be transmitted on the PDCCH along with a plurality of power control commands for a plurality of access terminals (e.g., transmit power control-physical downlink control channel (TPC-PDCCH)). Likewise, the PDCCH may be an L1/L2 control information channel (e.g., for LTE … …). As such, the first TPC-PDCCH may be related to the PUCCH and the second TPC-PDCCH may be related to the PUSCH (e.g., which may be particularly related to a persistently scheduled PUSCH). By way of another example, periodic updates of the uplink power level may also be sent on an aperiodic basis.

Turning to fig. 10, illustrated is a methodology 1000 that facilitates employing power control commands in a wireless communication environment. At 1002, data may be transmitted on an uplink at a power level. For example, data may be transmitted on PUSCH; thus, data can be transmitted aperiodically. Pursuant to another example, the data transmission can be sent periodically (e.g., in connection with a set of periodic transmissions such as SRS transmissions, CQI transmissions, PUCCH transmissions, and so forth). At 1004, the power control command may be received via a layer 1/layer 2(L1/L2) control information channel for Downlink (DL) allocation and Uplink (UL) grants. The power control command may be sent on the downlink upon the occurrence of a trigger condition or by the opportunity for sending the power control command (e.g., because of transmission of a UL grant). For example, in contrast to techniques that use fixed, preset locations and channels to transmit power control commands, power control commands may be transmitted over the downlink on available channels when needed. According to this example, power control commands may be obtained on the PDCCH along with DL assignments or UL grants at a first time, while power control commands may be received on the TPC-PDCCH at a different time. Further, power control commands transmitted on the L1/L2 control information channel may be generated at the eNode B receiver based on a wideband received power or signal-to-noise ratio (SNR) estimate constructed from a set of signals transmitted on the uplink (e.g., data transmitted on the uplink at 1002). The power control commands may be single bit commands and/or multi-bit commands. Further, the power control commands may be obtained via PDCCH or PDCCH/PDSCH pairs. In addition, the power control commands may be received as a separate transmission or in-band with other data transmitted from the base station. By way of another illustration, power control commands can be received at multiple locations, that is, can be obtained on the PDCCH along with DL assignments or UL grants and/or along with power control commands for multiple access terminals (e.g., TPC-PDCCH). In accordance with this illustrative example, power control commands obtained via PDCCH with DL allocations may relate to PUCCH, and power control commands received via PDCCH with UL grants may relate to PUSCH. According to another example, two TPC-PDCCHs may be used: a first TPC-PDCCH may be used to provide power control commands related to PUCCH and a second TPC-PDCCH may be used to transmit power control commands related to PUSCH (e.g., which may be particularly relevant to persistently scheduled PUSCH). At 1006, the power level may be changed based on the power control command. Furthermore, such a change to the power level need not be made when no power control command is obtained. According to another example, the power level may be changed using an open loop power control mechanism, whether or not power control commands are received and used to adjust the power level. At 1008, data may be transmitted on the uplink at the changed power level. Further, data may be transmitted at a first power level at a particular time without receiving a power control command in response, and the first power level may be used for a next data transmission on the uplink. By way of another example, periodic updates to the uplink power level may also be received on an aperiodic adjustment basis.

In accordance with one or more aspects described herein, it will be appreciated that inferences can be made regarding utilizing aperiodic power control commands. As used herein, the term to "infer" or "inference" refers generally to the process of reasoning about or inferring states of the system, environment, and/or user from a set of observations as captured via events and/or data. Inference can be employed to identify a specific context or action, or can generate a probability distribution over states, for example. The inference can be probabilistic-that is, the computation of a probability distribution over states of interest based on a consideration of data and events. Inference can also refer to techniques employed for composing higher-level events from a set of events and/or data. Such inference results in the construction of new events or actions from a set of observed events and/or stored event data, whether or not the events are correlated in close proximity in time, and whether the events and data come from one or several event and data sources.

According to an example, one or more methods presented above can include making inferences pertaining to determining whether to send a power control command based on a transmission received at a base station. By way of further illustration, inferences can be made regarding determining when to listen for power control commands being transmitted on the downlink. It will be appreciated that the foregoing examples are illustrative in nature and are not intended to limit the number of inferences that can be made in conjunction with the various embodiments and/or methods described herein and the manner in which such inferences are made.

Fig. 11 is an illustration of an access terminal 1100 that facilitates utilizing aperiodic power control commands in an LTE based wireless communication system. Access terminal 1100 includes a receiver 1102 that receives a signal from a receive antenna (not shown), performs typical operations on the received signal (e.g., filters, methods, downconverts, etc.) and digitizes the conditioned signal to obtain samples. Receiver 1102 can be, for example, an MMSE receiver, and can comprise a demodulator 1104 that can demodulate received symbols and provide them to a processor 1106 for channel estimation. Processor 1106 can be a processor dedicated to analyzing information received by receiver 1102 and/or generating information for transmission by a transmitter 1106, a processor that controls one or more components of access terminal 1100, and/or a processor that both analyzes information received by receiver 1102, generates information for transmission by a transmitter 1116, and controls one or more components of access terminal 1100.

Additionally, access terminal 1100 can comprise memory that is operatively coupled to processor 1106 and that can store data to be transmitted, received data, an identifier assigned to access terminal 1100, information related to obtained aperiodic power control command, and any other suitable information for selecting whether to execute an aperiodic power control command. Additionally, memory 1108 can store protocols and/or algorithms related to interpreting whether aperiodic power control command is directed to access terminal 1100.

It will be appreciated that the data store (e.g., memory 1108) 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 (DDR SDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), and Direct Rambus RAM (DRRAM). The memory 1108 of the subject systems and methods is intended to comprise, without being limited to, these and any other suitable types of memory.

Receiver 1102 can also be operatively connected to an UL power manager 1110 that controls a power level used by access terminal 1100 for transmitting via the uplink. UL power manager 1110 can set an uplink power level for transmitting data, control signals, etc., via any type of uplink channel. UL power manager 1110 may use an open loop mechanism for selecting the uplink power level. In addition, receiver 1102 and UL power manager 1110 can be coupled to aperiodic command receiver 1112, which can evaluate aperiodic power control commands obtained through receiver 1102. Aperiodic command receiver 1112 interprets when an aperiodic power control command directed to access terminal 1100 is sensed. In addition, aperiodic command receiver 1112 determines that a particular aperiodic power control command should be decoded, used, etc. In addition, aperiodic command receiver 1112 (and/or UL power manager 1110) can vary an uplink power level utilized by access terminal 1110 in accordance with the aperiodic power control command. Access terminal 1100 also comprises a modulator 1114 and a transmitter 1116, e.g., transmitter 1116 transmits the signal to a base station, another access terminal, etc. Although depicted as being separate from the processor 1106, it is to be appreciated that the UL power manager 1110, the aperiodic command receiver 11112, and/or the modulator 1114 can be part of the processor 1106 or multiple processors (not shown).

Fig. 12 is an illustration of a system 1200 that facilitates generating aperiodic power control commands in an LTE based wireless communication environment. System 1200 includes a base station 1202 (e.g., an access point) having a receiver 1210 and a transmitter 1224, receiver 1210 can receive signal(s) from one or more access terminals 1204 via a plurality of receive antennas 1206, and transmitter 1222 can transmit to the one or more access terminals 1204 via a transmit antenna 1208. Receiver 1210 can receive information from receive antennas 1206 and is operatively associated with a demodulator 1212 that demodulates received information. Demodulated symbols can be analyzed by a processor 1214, which processor 1214 can be similar to that described above with respect to fig. 11, and can be coupled to a memory 1216 that stores information related to an access terminal identifier (e.g., MACID … …), data to be transmitted to or received from access terminal 1204 (or a disparate base station (not shown)) (e.g., aperiodic power control command … …), and/or any other suitable information related to performing the various operations and functions presented herein. Processor 1214 is also connected to a received power monitor 1218 that accesses an uplink power level utilized by access terminal 1204 based on signals obtained at base station 1202. For example, received power monitor 1218 may analyze the uplink power level from the PUSCH transmission. According to another illustration, received power monitor 1218 can estimate an uplink power level from the periodic uplink transmission.

Received power monitor 1218 may be operably connected to aperiodic corrector 1220 that varies the estimated uplink power level as needed. The adjustment by aperiodic corrector 1220 may be triggered based on the occurrence of a predetermined condition, which may be identified based on the measurement. Further, aperiodic corrector 1220 may determine how much adjustment to make to the uplink power level when such adjustments are deemed necessary. Further, aperiodic corrector 1220 can generate aperiodic power control commands, which can then be transmitted to an intended corresponding access terminal 1204. In addition, aperiodic corrector 1220 can be operably coupled to modulator 1222. A modulator 1222 can multiplex the aperiodic power control command for transmission by a transmitter 1226 through antenna 1208 to access terminal 1204. Although depicted as being separate from the processor 1214, it is to be appreciated that received power monitor 1218, aperiodic corrector 1220, and/or modulator 1222 can be part of processor 1214 or a number of processors (not shown).

Fig. 13 illustrates an exemplary wireless communication system 1300. For simplicity, wireless communication system 1300 depicts one base station 1310 and one access terminal 1350. However, it is to be appreciated that system 1300 can include more than one base station and/or more than one access terminal, wherein additional base stations and/or access terminals can be substantially similar or different from example base station 1310 and access terminal 1350 described below. In addition, it is to be appreciated that base station 1310 and/or access terminal 1350 can employ the systems (fig. 1-5, 11-12, and 14-15) and/or methods (fig. 9-10) described herein to facilitate wireless communication there between.

At base station 1310, traffic data for a number of data streams is provided from a data source 1312 to a Transmit (TX) data processor 1314. According to one example, each data stream can be transmitted over a respective antenna. TX data processor 1314 formats, codes, and interleaves the traffic data stream based on a particular coding scheme selected for that data stream to provide coded data.

The coded data for each data stream can be multiplexed with pilot data using Orthogonal Frequency Division Multiplexing (OFDM) techniques. Additionally or alternatively, the pilot symbols may be frequency division multiplexed (FDD), Time Division Multiplexed (TDM), or Code Division Multiplexed (CDM). The pilot data is typically a known data pattern that is processed in a known manner and can be used at access terminal 1350 to estimate channel response. The multiplexed pilot and coded data for each data stream can be modulated (e.g., symbol mapped) based on a particular modulation scheme (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM), etc.) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream can be determined by instructions performed or provided by processor 1330.

The modulation symbols for the data streams can be provided to a TX MIMO processor 1320, which can further process the modulation symbols (e.g., for OFDM). TX MIMO processor 1320 then provides NT modulation symbol streams to NT transmitters (TMTR)1322a through 1322 t. In various embodiments, TX MIMO processor 1320 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter 1322 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. Further, NT modulated signals from transmitters 1322a through 1322t are transmitted from NT antennas 1324a through 1324t, respectively.

At access terminal 1350, the transmitted modulated signals are received by NR antennas 1352a through 1352r and the received signal from each antenna 1352 is provided to a respective receiver (RCVR)1354a through 1354 r. Each receiver 1354 conditions (e.g., filters, amplifies, and downconverts) a respective signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding "received" symbol stream.

An RX data processor 1360 can receive and process the NR received symbol streams from NR receivers 1354 based on a particular receiver processing technique to provide NT "detected" symbol streams. RX data processor 1360 can demodulate, deinterleave, and decode each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor 1360 is complementary to that performed by TX MIMO processor 1320 and TX data processor 1314 at base station 1310.

Processor 1370 may periodically determine which available technology to use as discussed above. Further, processor 1370 can generate a reverse link message including a matrix index portion and a rank value portion.

The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message may be processed by a TX data processor 1338, modulated by a modulator 1380, conditioned by transmitters 1354a through 1354r, and transmitted back to base station 1310; TX data processor 1338 can also receive traffic data for a number of data streams from a data source 1336.

At base station 1310, the modulated signals from access terminal 1350 are received by antennas 1324, conditioned by receivers 1322, demodulated by a demodulator 1340, and processed by a RX data processor 1342 to extract the reverse link message transmitted by access terminal 1350. Further, processor 1330 can process the extracted message to determine which precoding matrix to use for determining the beamforming weights.

Processors 1330 and 1370 can direct (e.g., control, regulate, manage, etc.) operation at base station 1310 and access terminal 1350, respectively. Respective processors 1330 and 1370 can be associated with memory 1332 and 1372 that store program codes and data. Processors 1330 and 1370 can also perform computations to derive frequency and impulse response estimates for the uplink and downlink, respectively.

It is to be understood that the embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For a hardware implementation, the processing units may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof.

When the embodiments are implemented in software, firmware, middleware or microcode, program code or code segments, they can be stored in a machine-readable medium, such as a storage component. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program declarations. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, network transmission, etc.

For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in memory units and executed by processors. The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

Referring to fig. 14, illustrated is a system 1400 that enables generating power control commands for use by access terminals in a wireless communication environment. For example, system 1400 can reside at least partially within a base station. It is to be appreciated that system 1400 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 1400 includes a logical grouping 1402 of electrical components that can act in conjunction. For instance, logical grouping 1402 can include an electrical component for obtaining uplink transmissions sent from an access terminal at an uplink power level 1404. Moreover, logical grouping 1402 can include an electrical component for evaluating whether to change an uplink power level utilized by the access terminal 1406. Moreover, logical grouping 1402 can include an electrical component for transmitting a power control command via an L1/L2 control information channel for Downlink (DL) allocation and Uplink (UL) grant 1408 wherein the power control command is for adjusting an uplink power level by a particular amount. For example, power control commands may be generated and transmitted as needed. Additionally, system 1400 can include a memory 1410 that retains instructions for executing functions associated with electrical components 1404, 1406, and 1408. While shown as being external to memory 1410, it is to be understood that one or more of electrical components 1404, 1406, and 1408 can exist within memory 1410.

Turning to fig. 15, illustrated is a system 1500 that enables employing power control commands in a wireless communication environment. System 1500 can reside within an access terminal, for instance. As depicted, system 1500 includes functional blocks that can represent functions implemented by a processor, software, or combination thereof (e.g., firmware). System 1500 includes a logical grouping 1502 of electrical components that can act in conjunction. Logical grouping 1502 may include an electrical component for transmitting data on the uplink at a power level 1504. Moreover, logical grouping 1502 can include an electrical component for obtaining a power control command via an L1/L2 control information channel for Downlink (DL) allocation and Uplink (UL) grants 1506. Moreover, logical grouping 1502 can include an electrical component for changing a power level for a subsequent data transmission as a function of the power control command 1508. According to another illustration, additionally or alternatively, the power level for subsequent data transmissions may be changed based on an open loop power control mechanism. Additionally, system 1500 can include a memory 1510 that retains instructions for executing functions associated with electrical components 1504, 1506, and 1508. While shown as being external to memory 1510, it is to be understood that electrical components 1504, 1506, and 1508 can exist within memory 1510.

What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim.

Claims (82)

1. A method that facilitates generating power control commands in a wireless communication environment, comprising:

receiving an uplink transmission from an access terminal;

determining whether to adjust an uplink power level used by the access terminal; and

transmitting power control commands to the access terminal to change the uplink power level using a layer 1/layer 2(L1/L2) control information channel for Downlink (DL) allocation and Uplink (UL) grants.

2. The method of claim 1, wherein the uplink transmission is a Physical Uplink Shared Channel (PUSCH) transmission.

3. The method of claim 1, wherein the uplink transmission is from a set of periodic uplink transmissions sent by the access terminal.

4. The method of claim 1, further comprising:

comparing the uplink power level to a target; and

an adjustment is triggered when a difference between the uplink power level and the target exceeds a threshold.

5. The method of claim 1, further comprising determining an amount of adjustment to the uplink power level, the amount included in the power control command.

6. The method of claim 1, further comprising transmitting the power control commands on an as-needed basis.

7. The method of claim 1, the power control command is a single bit correction to the uplink power level.

8. The method of claim 1, the power control command is a multi-bit correction to the uplink power level.

9. The method of claim 1, further comprising mapping the power control commands to specific instances of at least one of a Physical Downlink Control Channel (PDCCH) or a physical downlink control channel/physical downlink shared channel (PDCCH/PDSCH) pair.

10. The method of claim 1, further comprising transmitting the power control command as a separate transmission.

11. The method of claim 1, further comprising sending the power control command in-band with a different data transmission.

12. The method of claim 1, further comprising sending the power control commands on the layer 1/layer 2(L1/L2) control information channel available at transmission and when necessary.

13. The method of claim 1, further comprising:

constructing at least one of a wideband received power estimate or a signal-to-noise ratio estimate from the received uplink transmission; and

determining whether to adjust the uplink power level based on the at least one of the wideband received power estimate or the signal-to-noise ratio estimate.

14. The method of claim 1, further comprising transmitting the power control command via a Physical Downlink Control Channel (PDCCH) with a downlink assignment, the power control command being related to a Physical Uplink Control Channel (PUCCH).

15. The method of claim 1, further comprising transmitting the power control command via a Physical Downlink Control Channel (PDCCH) with an uplink grant, the power control command being related to a Physical Uplink Shared Channel (PUSCH).

16. The method of claim 1, further comprising sending the power control commands with power control commands for at least one disparate access terminal via at least one transmit power control-physical downlink control channel (TPC-PDCCH).

17. The method of claim 1, further comprising transmitting a periodic update to the uplink power level on an aperiodic adjustment basis.

18. A wireless communications apparatus, comprising:

a receive power monitor to obtain uplink transmissions sent from an access terminal at an uplink power level; and

an uplink power adjuster to: interpreting whether to change the uplink power level; estimating an amount by which to adjust the uplink power level when changing the uplink power level; and transmitting power control commands to the access terminal via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants to change the uplink power level.

19. The wireless communications apparatus of claim 18, wherein the uplink transmission is a Physical Uplink Shared Channel (PUSCH) transmission.

20. The wireless communications apparatus of claim 18, wherein the uplink transmission is from a set of periodic uplink transmissions transmitted by the access terminal.

21. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to compare the uplink power level to a target power level and trigger adjustment when a difference between the uplink power level and the target power level exceeds a threshold.

22. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit the power control commands on an as-needed basis.

23. The wireless communications apparatus of claim 18, wherein the power control command includes a single bit correction to the uplink power level.

24. The wireless communications apparatus of claim 18, wherein the power control command includes a multi-bit correction to the uplink power level.

25. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to map the power control commands to specific instances of at least one of a Physical Downlink Control Channel (PDCCH) or a physical downlink control channel/physical downlink shared channel (PDCCH/PDSCH) pair.

26. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit the power control command in at least one of: sent as a separate transmission or sent in-band with different data transmissions.

27. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit the power control commands when necessary and on the layer 1/layer 2(L1/L2) control information channel available at transmission.

28. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to construct at least one of a wideband received power estimate or a signal-to-noise ratio estimate from the obtained uplink transmission and interpret whether to change the uplink power level based on the at least one of the wideband received power estimate or the signal-to-noise ratio estimate.

29. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit the power control command via a Physical Downlink Control Channel (PDCCH) with a downlink assignment, the power control command related to a Physical Uplink Control Channel (PUCCH).

30. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit the power control command via a Physical Downlink Control Channel (PDCCH) with an uplink grant, the power control command related to a Physical Uplink Shared Channel (PUSCH).

31. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit the power control commands with power control commands for at least one disparate access terminal via at least one transmit power control-physical downlink control channel (TPC-PDCCH).

32. The wireless communications apparatus of claim 18, wherein the uplink power adjuster is further configured to transmit periodic updates to the uplink power level on an aperiodic adjustment basis.

33. A wireless communications apparatus that enables generating power control commands for use by an access terminal in a wireless communication environment, comprising:

means for obtaining an uplink transmission sent from an access terminal at an uplink power level;

means for evaluating whether to change the uplink power level used by the access terminal; and

means for sending a power control command via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants, the power control command adjusting the uplink power level by a particular amount.

34. The wireless communications apparatus of claim 33, wherein the uplink transmission is at least one of: a Physical Uplink Shared Channel (PUSCH) transmission, or a transmission from a set of periodic uplink transmissions sent by the access terminal.

35. The wireless communications apparatus of claim 33, further comprising:

means for comparing the uplink power level to a target; and

means for triggering an adjustment when a difference between the uplink power level and the target exceeds a preset value.

36. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control commands on an as-needed basis.

37. The wireless communications apparatus of claim 33, wherein the power control command includes a single bit correction to the uplink power level.

38. The wireless communications apparatus of claim 33, wherein the power control command includes a multi-bit correction to the uplink power level.

39. The wireless communications apparatus of claim 33, further comprising means for mapping the power control commands to specific instances of at least one of a Physical Downlink Control Channel (PDCCH) or a physical downlink control channel/physical downlink shared channel (PDCCH/PDSCH) pair.

40. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control command in at least one of: sent as a separate transmission or sent in-band with different data transmissions.

41. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control commands when necessary and on the layer 1/layer 2(L1/L2) control information channel available at time of transmission.

42. The wireless communications apparatus of claim 33, further comprising means for constructing at least one of a wideband received power estimate or a signal-to-noise ratio estimate from the obtained uplink transmission for use in estimating whether to alter the uplink power level.

43. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control command via a Physical Downlink Control Channel (PDCCH) with a downlink assignment, the power control command related to a Physical Uplink Control Channel (PUCCH).

44. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control command via a Physical Downlink Control Channel (PDCCH) with an uplink grant, the power control command being related to a Physical Uplink Shared Channel (PUSCH).

45. The wireless communications apparatus of claim 33, further comprising means for transmitting the power control commands with power control commands for at least one disparate access terminal via at least one transmit power control-physical downlink control channel (TPC-PDCCH).

46. The wireless communications apparatus of claim 33, further comprising means for transmitting periodic updates to the uplink power level on an aperiodic adjustment basis.

47. A method that facilitates employing power control commands in a wireless communication environment, comprising:

transmitting data on an uplink at a power level;

receiving power control commands via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants;

changing the power level based on the power control command; and

transmitting data on the uplink at the changed power level.

48. The method of claim 47, wherein the data is transmitted on a Physical Uplink Shared Channel (PUSCH).

49. The method of claim 47, wherein the power control command is a single bit command.

50. The method of claim 47, wherein the power control command is a multi-bit command.

51. The method of claim 47, wherein the power control command is transmitted on the layer 1/layer 2(L1/L2) control information channel when a trigger condition occurs.

52. The method of claim 47, further comprising receiving the power control command via at least one of a Physical Downlink Control Channel (PDCCH) or a physical downlink control channel/physical downlink shared channel (PDCCH/PDSCH) pair.

53. The method of claim 47, further comprising receiving the power control command in at least one of the following ways: received as a separate transmission or received in-band with a different data transmission.

54. The method of claim 47, further comprising using a constant power level when the power control command is not received.

55. The method of claim 47, further comprising adjusting the power level by using an open loop power control mechanism regardless of whether the power control command is received.

56. The method of claim 47, further comprising receiving the power control commands when necessary on the layer 1/layer 2(L1/L2) control information channel available at transmission.

57. The method of claim 47, further comprising receiving the power control command via a Physical Downlink Control Channel (PDCCH) with a downlink assignment, the power control command related to transmitting data on a Physical Uplink Control Channel (PUCCH).

58. The method of claim 47, further comprising receiving the power control command via a Physical Downlink Control Channel (PDCCH) with an uplink grant, the power control command related to transmitting data on a Physical Uplink Shared Channel (PUSCH).

59. The method of claim 47, further comprising receiving power control commands for at least one disparate access terminal via at least one transmit power control-physical downlink control channel (TPC-PDCCH).

60. The method of claim 47, further comprising receiving periodic updates to the power level based on aperiodic adjustments.

61. A wireless communications apparatus, comprising:

a transmitter for transmitting data on an uplink at a power level; and

an uplink power manager to: obtaining power control commands via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants; and adjusting the power level for subsequent data transmissions based on the power control command.

62. The wireless communications apparatus of claim 61, wherein the data is transmitted on a Physical Uplink Shared Channel (PUSCH).

63. The wireless communications apparatus of claim 61, wherein the power control command is transmitted on the layer 1/layer 2(L1/L2) control information channel when a trigger condition occurs.

64. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to obtain the power control commands via at least one of a Physical Downlink Control Channel (PDCCH) or a physical downlink control channel/physical downlink shared channel (PDCCH/PDSCH) pair.

65. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to obtain the power control command in at least one of: obtained as a separate transmission or obtained in-band with different data transmissions.

66. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to adjust the power level using an open loop power control mechanism regardless of whether the power control command is received.

67. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to obtain the power control commands when necessary over the layer 1/layer 2(L1/L2) control information channel available at the time of transmission.

68. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to obtain the power control command via a Physical Downlink Control Channel (PDCCH) with a downlink assignment, the power control command relates to a subsequent data transmission on a Physical Uplink Control Channel (PUCCH).

69. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to obtain the power control command via a Physical Downlink Control Channel (PDCCH) with an uplink grant, the power control command relating to a subsequent data transmission on a Physical Uplink Shared Channel (PUSCH).

70. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to obtain the power control commands via at least one transmit power control-physical downlink control channel (TPC-PDCCH) with power control commands for at least one disparate access terminal.

71. The wireless communications apparatus of claim 61, wherein the uplink power manager is further configured to receive periodic updates to the power level based on aperiodic adjustments.

72. A wireless communications apparatus that enables employing power control commands in a wireless communication environment, comprising:

means for transmitting data on an uplink at a power level;

means for obtaining power control commands via a layer 1/layer 2(L1/L2) control information channel used for Downlink (DL) allocation and Uplink (UL) grants; and

means for changing the power level for a subsequent data transmission in accordance with the power control command.

73. The wireless communications apparatus of claim 72, further comprising means for transmitting the data on a Physical Uplink Shared Channel (PUSCH).

74. The wireless communications apparatus of claim 72, wherein the power control command is transmitted on the layer 1/layer 2(L1/L2) control information channel when a trigger condition occurs.

75. The wireless communications apparatus of claim 72, further comprising means for obtaining the power control command via at least one of a Physical Downlink Control Channel (PDCCH) or a physical downlink control channel/physical downlink shared channel (PDCCH/PDSCH) pair.

76. The wireless communications apparatus of claim 72, further comprising means for obtaining the power control command in at least one of: obtained as a separate transmission or obtained in-band with different data transmissions.

77. The wireless communications apparatus of claim 72, further comprising means for varying the power level using an open loop power control mechanism regardless of whether the power control command is obtained at a given time.

78. The wireless communications apparatus of claim 72, further comprising means for obtaining the power control commands when necessary over the layer 1/layer 2(L1/L2) control information channel available at a time of transmission.

79. The wireless communications apparatus of claim 72, further comprising means for obtaining the power control command via a Physical Downlink Control Channel (PDCCH) along with a downlink assignment, the power control command related to a subsequent data transmission on a Physical Uplink Control Channel (PUCCH).

80. The wireless communications apparatus of claim 72, further comprising means for obtaining the power control command via a Physical Downlink Control Channel (PDCCH) with an uplink grant, the power control command relating to a subsequent data transmission on a Physical Uplink Shared Channel (PUSCH).

81. The wireless communications apparatus of claim 72, further comprising means for obtaining power control commands for at least one disparate access terminal via at least one transmit power control-physical downlink control channel (TPC-PDCCH).

82. The wireless communications apparatus of claim 72, further comprising means for further obtaining periodic updates to the power level based on aperiodic adjustments.