Uplink power control for lte

ES 2 579 205 T3

DESCRIPTION

Uplink Power Control for LTE

I. Field

The following description generally refers to wireless communications and. more particularly, to the control of uplink power levels (UL) used by access terminals in a wireless communication system based on long-term evolution (LTE).

II. Background

Wireless communication systems are widely used to provide various types of communication; for example, voice and / or data can be provided through such wireless communication systems. A typical wireless communication system, or network, can provide multiple users with access to one or more shared resources (eg, bandwidth, transmission power, etc.). For example, a system may use a variety of 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 others. Furthermore, the system can conform to specifications such as Third Generation Partnership Project (3GPP), Long Term Evolution (LTE) of 3GPP, etc.

In general, multiple access wireless communication systems can simultaneously support communications for multiple access terminals. Each access terminal can communicate with one or more base stations through forward and reverse link transmissions. Forward link (or downlink) refers to the communication link from the base stations to the access terminals, and the reverse link (or uplink) refers to the communication link from the access terminals to the base stations. This communication link can be established through a single input-single output (SISO) system, multiple inputs-single output (MISO), single input-multiple outputs (SIMO), or a multiple input-multiple outputs (MIMO) system. ).

Wireless communication systems often employ one or more base stations and sectors therein that provide a coverage area. A typical sector may transmit multiple data streams for broadcast, multicast, and / or unicast services, where a data stream may be a data stream that may be of independent reception interest to an access terminal. An access terminal may be used within the coverage area of ​​said sector to receive one, more than one, or all of the data streams carried by the composite stream. Also, an access terminal can transmit data to the base station or another access terminal. With so many access terminals transmitting signal data in close proximity, control power is important to produce sufficient signal-to-noise ratios (SNRs) at different data rates and transmission bandwidths for uplink communications. It is desirable to keep the overhead incurred from transmitting the power settings to these access terminals as low as possible while achieving the goals mentioned above.

Document WO 2006/104208 discloses a transmit power control method for controlling a transmit power of an uplink control channel in a mobile station. A radio network controller is used to determine a transmission period and to notify the mobile station of the transmission period. The mobile station transmits an outer loop control signal through a data channel in the transmission period. The channel reception quality is determined by a radio base station, which allows the radio network controller to determine a transmission power imbalance of the data channel that is signaled to the mobile station. The mobile station then controls the transmit power for future data transmissions based on the received transmit power imbalance. Document US 2003/0003875 also refers to power control in a communication system, and in particular to power control when there is an interruption in communications. In this case, a signal independent of the communication data is used by the receiving station to detect power control instructions.

RESUME

The following is a simplified summary of one or more embodiments in order to provide a basic understanding of those embodiments. This summary is not a comprehensive overview of all contemplated embodiments and is not intended to identify key or critical elements of all embodiments or to delineate the scope of some or all of the embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified manner as a prelude to the more detailed description that will be presented later.

In accordance with one or more embodiments and the corresponding disclosure thereof, various aspects are described in relation to facilitating the use of aperiodic closed-loop power control corrections in

ES 2 579 205 T3 a wireless communication environment based on long-term evolution (LTE). An aperiodic power control command can be sent over a downlink to control and / or correct an uplink power level employed by an access terminal. The transmission of the aperiodic power control can be triggered by a measurement (for example, a received power that is outside a set range, etc.), or by the timing of transmission of control information from the sector to the access terminal at the downlink. The aperiodic power control command may include a single bit correction and / or a multi-bit correction. In addition, the access terminal can alter the uplink power level used for subsequent uplink transmissions based on the aperiodic power control command when it is received. Additionally, regardless of whether the aperiodic power control command is received at a particular time on the downlink, the access terminal can employ periodic power control commands and an open-loop power control mechanism to adjust the level of power. uplink power.

In accordance with related aspects, a method that facilitates the generation of power control commands in a wireless communication environment is described herein. The method may include receiving uplink transmissions from an access terminal. Furthermore, the method may comprise determining whether to adjust an uplink power level employed by the access terminal. Additionally, the method may include transmitting power control commands to the access terminal to alter the uplink power level using a layer 1 / layer 2 (L1 / L2) control information channel used for downlink assignments ( DL) and downlink grants (UL).

Another aspect relates to a wireless communication apparatus. The wireless communications apparatus may include a memory that holds instructions related to obtaining uplink transmissions sent from an access terminal at an uplink power level, decrypting whether to alter the uplink power level, evaluating an amount to adjust the uplink power level when making the alteration in the uplink power level, and sending power control commands to the access terminal to alter the uplink power level through a layer 1 / layer 2 (L1 / L2) control information channel used for downlink assignments (DL ) and downlink grants (UL). In addition, the wireless communications apparatus may include a processor, coupled to memory, configured to execute instructions stored in memory.

Still another aspect relates to a wireless communication apparatus that allows to produce power control commands for use by access terminals in a wireless communication environment. The wireless communications apparatus may include means for obtaining uplink transmissions sent from an access terminal at an uplink power level. Additionally, the wireless communications apparatus may comprise means for evaluating whether to alter the uplink power level employed by the access terminal. In addition, the wireless communications apparatus may include means for sending power control commands through a layer 1 / layer 2 (L1 / L2) control information channel used for downlink (DL) assignments and link grants. downlink (UL), power control commands adjust the uplink power level by a specified amount.

Still another aspect relates to a machine-readable medium having machine-executable instructions stored therein for obtaining uplink transmissions sent from an access terminal at an uplink power level; evaluating whether to alter the uplink power level employed by the access terminal; and send power control commands through a layer 1 / layer 2 (L1 / L2) control information channel used for downlink (DL) assignments and downlink (UL) grants, the control commands of power adjusts the uplink power level by a specified amount.

In accordance with another aspect, an apparatus in a wireless communication system may include a processor, wherein the processor may be configured to receive uplink transmissions from an access terminal. In addition, the processor can be configured to determine whether to adjust an uplink power level used by the access terminal. Additionally, the processor can be configured to transmit power control commands to the access terminal via a Layer 1 / Layer 2 (L1 / L2) control information channel used for downlink (DL) assignments and link grants. downlink (UL), power control commands alter the uplink power level when triggered by a measurement.

In accordance with other aspects, a method that facilitates the use of power control commands in a wireless communication environment is described herein. The method may include transmitting data on a power level uplink. Additionally, the procedure may include receiving a power control command via a Layer 1 / Layer 2 (L1 / L2) control information channel used for downlink (DL) assignments and downlink (UL) grants. . The method may also include altering the power level based on the power control command. Furthermore, the method may comprise transmitting data on the uplink at the altered power level.

ES 2 579 205 T3

Another additional aspect refers to a wireless communications apparatus that can include a memory that stores instructions related to sending data on an uplink at power level, obtaining a power control command through an information channel. Layer 1 / Layer 2 (L1 / L2) control system used for downlink assignments (DL) and downlink grants (UL), and adjusting the power level based on the power control command for a subsequent data transmission. In addition, the wireless communications apparatus may comprise a processor, coupled to memory, configured to execute instructions stored in memory.

Another aspect relates to a wireless communication apparatus that enables power control commands to be used in a wireless communication environment. The wireless communications apparatus may comprise means for avoiding data on a power level uplink. In addition, the wireless communications apparatus may include means for obtaining a power control command through a Layer 1 / Layer 2 (L1 / L2) control information channel used for downlink (DL) assignments and leases. downlink (UL). Furthermore, the wireless communication apparatus may include means for changing the power level for subsequent data transmission as a function of the power control command.

Still another aspect refers to a machine-readable medium that has stored in it machine-executable instructions to send data in an uplink at power level, obtain a power control command through a channel of control information of Layer 1 / Layer 2 (L1 / L2) used for downlink assignments (DL) and downlink grants (UL), and changing the power level for a subsequent data transmission based on the power control command.

In accordance with another aspect, an apparatus in a wireless communication system may include a processor, wherein the processor may be configured to transmit data on a power level uplink. Additionally, the processor can be configured to receive a power control command through a Layer 1 / Layer 2 (L1 / L2) control information channel used for downlink assignments (DL) and downlink grants (UL ). In addition, the processor can be configured to alter the power level based on the power control command. Additionally, the processor can be configured to transmit data on the uplink at the altered power level.

To achieve the foregoing and related objectives, the one or more embodiments comprise the features described in greater detail below and set forth particularly in the claims. The following description and accompanying drawings describe in detail certain illustrative aspects of the one or more embodiments. However, these aspects only indicate some of the various ways in which the principles of various embodiments can be used, and the described embodiments are intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an illustration of a wireless communication system in accordance with various aspects discussed herein.

Figure 2 is an illustration of an exemplary system that controls the uplink power level (s) employed by an access terminal or terminals in an LTE-based wireless communication environment.

Figure 3 is an illustration of an exemplary system that periodically corrects an uplink power level employed by an access terminal.

Figure 4 is an illustration of an exemplary system that aperiodically transfers power control commands to access terminals in an LTE-based wireless communication environment.

Figure 5 is an illustration of an exemplary system grouping access terminals to send power control commands on a downlink.

Figure 6 is an illustration of exemplary transmission structures for communicating power control commands to groups of access terminals.

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

Figure 8 is an illustration of an exemplary timing diagram for an aperiodic uplink power control procedure for LTE.

Figure 9 is an illustration of an exemplary methodology that facilitates the generation of control commands for

ES 2 579 205 T3 power in a wireless communication environment.

Figure 10 is an illustration of an exemplary methodology that facilitates the use of power control commands in a wireless communication environment.

Figure 11 is an illustration of an exemplary access terminal that facilitates using aperiodic power control commands in an LTE-based wireless communication system.

Figure 12 is an illustration of an exemplary system that facilitates producing aperiodic power control commands in an LTE-based wireless communication environment.

Figure 13 is an illustration of an exemplary wireless network environment that can be used in conjunction with the various systems and procedures described herein.

Figure 14 is an illustration of an exemplary system that enables power control commands to be produced for use by access terminals in a wireless communication environment.

Figure 15 is an illustration of an exemplary system that allows power control commands to be used in a wireless communication environment.

DETAILED DESCRIPTION

Various embodiments will now be described with reference to the drawings, in which the same reference numerals are used to refer to the same elements throughout. In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of one or more embodiments. However, it may be apparent that such an embodiment or embodiments can be practiced without these specific details. In other cases, widely known structures and devices are shown in block diagram form in order to facilitate the description of one or more embodiments.

As used in this application, the terms component, module, system and the like refer to an entity related to computing, whether it is hardware, firmware, a combination of hardware and software, software, or running software. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable, a thread, 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 in a process and / or thread of execution, and a component can be located on one computer and / or be distributed between two or more computers. Furthermore, these components can be run from various computer-readable media that have various data structures stored on them. The components can communicate by local and / or remote processes according to a signal that presents one or more data packets (for example, data from a component that interacts with another component in a local system, distributed system, and / or through a network , such as the Internet, with other systems through the signal).

Furthermore, various embodiments in relation to an access terminal are described herein. An access terminal may also be called a system, subscriber unit, subscriber station, mobile station, mobile, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, user device or user equipment (EU). An access terminal can be a mobile phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop station (WLL), a personal digital assistant (PDA), a handheld device capable of wireless connection, a computing device, or other processing device connected to a wireless modem. Furthermore, various embodiments in relation to a base station are described herein. A base station can be used in communications with an access terminal or terminals and can also be referred to as an access point, a Node B, an eNode B (eNB) or using other terminology.

In addition, various aspects or features described herein may be implemented as a method, apparatus, or article of manufacture using standard engineering and / or programming techniques. The term article of manufacture used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to, magnetic storage devices (for example, a hard disk, a floppy disk, magnetic tapes, etc.), optical discs (for example, a compact disk (CD ), a digital versatile disc (DVD), etc.), smart cards and flash memory devices (for example, EPROMs, cards, USB storage drives, etc.) Furthermore, various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The machine-readable middle term can include, but is not limited to, wireless channels and various other media that can store, contain and / or transport instructions and / or data.

ES 2 579 205 T3

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 that may include multiple groups of antennas. For example, one group of antennas can include antennas 104 and 106, another group can comprise antennas 108 and 110, and a further group can include antennas 112 and 114. Two antennas are illustrated for each group of antennas; however, a larger or smaller number of antennas can be used in each group. Base station 102 may further include a chain of transmitters and a chain of receivers, each of which may in turn comprise a plurality of components associated with the transmission and reception of signals (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by those skilled in the art.

The corresponding sector 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 substantially any number of access terminals similar to access terminals 116 and 122. Access terminals 116 and 122 can be, for example, cell phones, smart phones, laptops, handheld communication devices, handheld computing devices, satellite radios, global positioning systems, PDAs, and / or any other device suitable for communication. communication via wireless communication system 100. As shown, the access terminal 116 communicates with the antennas 112 and 114, while the antennas 112 and 114 transmit information to the access terminal 116 through a direct link 118 and receive information from the access terminal 116 through of a reverse link 120. In addition, the access terminal 122 communicates with the antennas 104 and 106, while the antennas 104 and 106 transmit information to the access terminal 122 through a direct link 124 and receive information from the access terminal 122 through a reverse link 126. In a frequency division duplex (FDD) system, the forward link 118 may use a different frequency band than that used by the reverse link 120, and the forward link 124 may use a different frequency band than the one used by the link. reverse 126, for example. In addition, in a time division duplex (TDD) system, the forward link 118 and the reverse link 120 may use a common frequency band, and the forward link 124 and reverse link 126 may use a common frequency band.

Each group of antennas and / or the area in which they are designated to communicate may be referred to as a base station sector 102, or as a cell of an eNB. For example, the antenna groups can be designed for communication with access terminals in a sector of the areas covered by the base station 102. In communication over direct links 118 and 124, base station transmit antennas 102 can use beamforming to improve the signal-to-radio ratio of direct links 118 and 124 for access terminals 116 and 122 . In addition, when base station 102 uses beamforming for transmissions to access terminals 116 and 122 randomly spread across an associated coverage, access terminals from neighboring cells may be subject to less interference compared to a base station that transmits through a single antenna to all its access terminals.

System 100 may be a long-term evolution (LTE) -based system, for example. In such a system 100, corresponding sectors of base station 102 can control the uplink power levels used by access terminals 116 and 122. Therefore, the system 100 can provide uplink power control (UL) that produces compensation for path loss and screen effect (for example, path loss and screen effect may change slowly with the time) and compensation for time variation interference from adjacent cells (eg, since system 100 may be an LTE-based system using frequency reuse 1). In addition, system 100 can mitigate large variations in the receive power obtained at base station 102 across users (for example, since users can multiplex into a common band). In addition, system 100 can compensate for multipath fading variations at sufficiently low speeds. For example, the channel coherence time for 3 km / h at different carrier frequencies can be as follows: a 900 MHz carrier frequency can have a 400 ms coherence time, a 2 GHz carrier frequency can have a coherence time of 180 ms, and a 3 GHz carrier frequency can have a coherence time of 120 ms. Therefore, depending on the latency and periodicity of the adjustments, fast fading effects can be corrected with low Doppler frequencies.

System 100 may employ uplink power control that combines open loop and closed loop power control mechanisms. According to one example, open loop power control can be used by each access terminal 116, 122 to establish power levels of a first preamble of a random access channel (RACH) communication. For the first preamble of a RACH, each access terminal 116, 122 may have obtained a downlink (DL) communication or communications from the base station 102, or the open loop mechanism may allow each access terminal 116, 122 select an uplink transmit power level that is inversely proportional to a receive power level related to the downlink communication (s) obtained. Therefore, downlink knowledge can be used by access terminals 116, 122 for uplink transmissions. The open loop mechanism can allow very fast adaptation to severe changes in radio conditions (eg depending on receive power filtering) by means of instantaneous power adjustments. In addition, the open loop mechanism can continue to operate more

ES 2 579 205 T3 beyond RACH processing as opposed to frequently employed conventional techniques. The closed loop mechanism can be used by system 100 once the random access procedure has been achieved. For example, closed-loop techniques may be employed when periodic uplink resources have been allocated to access terminals 116, 122 (for example, periodic uplink resources may be physical uplink control channel (PUCCH) resources or Sounding Reference Signal (SRS)). Furthermore, corresponding sectors in base station 102 (and / or a network) can control the uplink transmit power used by access terminals 116, 122 based on closed loop control.

The closed loop mechanism employed by system 100 can be periodic, aperiodic, or a combination of the two. Periodic closed-loop corrections can be periodically transmitted by the corresponding sector in base station 102 to access terminals 116, 122 (eg, once every 0.5 ms, 1 ms, 2 ms, 4 ms, ... ). For example, the periodicity may depend on the periodicity of the uplink transmissions. In addition, periodic corrections can be single-bit corrections (for example, up / down, ± 1 dB, ...) and / or multi-bit corrections (for example, ± 1 dB, ± 2 dB, ± 3 dB , ± 4 dB, ...). Therefore, the power control stage and the periodicity of the corrections can determine a maximum rate of change of the uplink power that the corresponding sector in the base station 102 (and / or the network) can control. According to another example, aperiodic corrections can be sent from the corresponding sector in the base station 102 to the corresponding access terminals 116, 122 as needed. Following this example, these corrections can be transmitted aperiodic when triggered by a network measurement (eg, receive power (RX) out of a set range, opportunity to send control information to a given access terminal, etc.). Additionally, aperiodic corrections can be single-bit and / or multi-bit (for example, corrections can be multi-bit since a significant portion of overhead associated with aperiodic corrections can be related to a correction schedule rather than a size). of correction). According to yet another example, aperiodic corrections can be transmitted by the corresponding sector at base station 102 to access terminals 116, 122 in addition to periodic corrections to minimize the overhead incurred in transmitting these power settings.

Turning now to FIG. 2, a system 200 is illustrated that controls the uplink power level (s) employed by the access terminal (s) in an LTE-based wireless communication environment. System 200 includes a sector in a base station 202 that can communicate with substantially any number of access terminals (not shown). In addition, the sector at base station 202 may include a received power monitor 204 that evaluates the power level (s) associated with an uplink signal (s) obtained from an access terminal (s). In addition, the sector at base station 202 may comprise an uplink power adjuster (UL) 206 that uses the analyzed power level (s) to generate the command (s) to alter the access terminal power levels.

Various physical channels (PHY) 208 can be used for communication between base station 202 and the access terminal (s); these physical channels 208 may include downlink physical channels and uplink physical channels. Examples of downlink physical channels include the physical downlink control channel (PDCCH), the physical downlink shared channel (PDSCH), and the common power control channel (CPCCH). PDCCH is a DL layer 1 / layer 2 (L1 / L2) control channel (e.g. PHY layer resource allocation for a DL or UL transmission) that has a capacity of about 30-60 bits and is protected by cyclic redundancy check (CRC). The PDCCH can carry uplink grants and downlink assignments. The PDSCH is a DL shared data channel; PDSCH can be a DL data channel shared between different users. The CPCCH is transmitted on the DL for multiple access terminals that control UL power. Corrections sent on the CPCCH can be single-bit or multi-bit. Furthermore, the CPCCH may be a particular exemplification of the PDCCH. Examples of uplink physical channels include the physical uplink control channel (PUCCH), the physical uplink shared channel (PUSCH), the probe reference signal (SRS), and the random access channel (RACH ). The PUCCH includes the Channel Quality Indicator (CQI) channel report, ACK channel, and UL requests. The PUSCH is a UL shared data channel. The SRS may be devoid of information and may allow channel polling in the UL to allow the channel to be sampled over part or all of the system bandwidth. It will be appreciated that the claimed subject matter is not limited to these exemplary physical channels 208.

The received power monitor 204 and the UL power adjuster 206 can provide closed loop power control for the uplink transmissions made by the access terminal (s). Operation in the LTE system can involve transmissions at one point in time over bandwidths that can be significantly less than the entire bandwidth of the system 200. Each access terminal can transmit over a small portion of the entire bandwidth of system 200 at any one time. Furthermore, frequency hopping may be employed by the access terminals; therefore, the corresponding sector in base station 202 may face difficulties when trying to evaluate adjustments to make the uplink power levels of the access terminals. Therefore, a suitable closed-loop power control mechanism provided by received power monitor 204 and UL power adjuster 206

ES 2 579 205 T3 builds a broadband reception power estimate from transmissions over multiple possible instants and on multiple possible PHY UL channels that allow adequate correction of path loss and screen effects regardless of bandwidth transmission band of the access terminal at any time.

The received power monitor 204 constructs the wideband receive power estimate from the channel sampling based on the access terminal transmissions in a variety of ways. For example, the received power monitor 204 may use the PUSCH for sampling. Following this example, the PUSCH transmission band is located in a certain interval. Diverse frequency scheduling can apply a pseudo-random hopping pattern to the transmission band at slot boundaries and possibly over retransmissions to fully exploit frequency diversity. PUSCH transmissions that exploit frequency selective programming will not apply a frequency hopping pattern on the transmission data and therefore may require more time to sample the channel or all frequencies (or most of it). Additionally, frequency selective programming can take advantage of the transmission of an SRS or a PUCCH. Frequency selective programming is a programming strategy that exploits channel selectivity; for example, frequency selective scheduling attempts to confine transmissions to the best subbands. This scheduling strategy may be relevant for low mobility access terminals. Furthermore, these transmissions are normally exclusive to frequency hopping techniques. Frequency diverse scheduling is an uneven scheduling strategy that uses the entire system bandwidth (eg, modulates the minimum transmission bandwidth capacity, etc.) to naturally obtain frequency diversity. Transmissions associated with diverse frequency programming can be associated with frequency hopping. Furthermore, frequency hopping may include changing the transmit frequency of a waveform in a pseudo-random manner to exploit frequency diversity from a channel point of view, as well as interference.

According to another example, the received power monitor 204 may use the PUCCH to sample the UL channel and therefore construct the wideband receive power estimate. The transmission band of the PUCCH can also be located in a given interval with hopping in the interval boundary in each transmission time interval (TTI). A busy band 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 over the PUCCH can be transmitted in-band with the rest of the data transmission (for example, to preserve the unique carrier property of the UL waveform) about the PUSCH. When the PUSCH is not transmitted on a particular TTI, the PUCCH can be transmitted on a localized band reserved for the transmission of the PUCCH at the edges of the system band.

According to another illustration, the SRS transmissions can be used by the received power monitor 204 to sample the channel and construct the wideband receive power estimate. The transmission band (in time) of the sRs can be substantially equal to the entire system band (or the minimum access terminal transmission bandwidth capacity). In a given SC-FDMA symbol (for example, the SC-FDMA symbol is a minimum unit of transmission in the UL of LTE), the transmission can be localized (for example, spanning a set of consecutive subcarriers that jumps in time) or distributed (for example, covering the entire band of the system or a portion of it, which may or may not jump, ...).

The received power monitor 204 builds the wideband receive power estimate from the channel sampling across the entire bandwidth of the system. However, depending on the way in which the system is sampled and / or if frequency hopping is applied to the transmissions, the time period to construct the wideband receive power estimate from the UL channel sampling by the received power monitor 204 may vary.

PUCCH transmissions when there is no UL data, take place at the edges of the system band. The transmission of the PUCCH when there is UL data can be localized in-band with the transmission of data over the PUSCH. Additionally, PUSCH transmissions may not change the transmit frequency or may not be hopping at all to exploit UL frequency selective programming; however, to allow frequency selective programming, SRS transmissions can be leveraged by FDD / TDD systems. Also, when the PUSCH uses frequency miscellaneous programming, a frequency hopping is applied to the transmissions.

Additionally, based on channel sampling performed by received power monitor 204, UL power adjuster 206 can generate a command that can alter the UL power level employed by a particular access terminal. The command can be a single bit correction (for example, up / down, ± 1 dB, ...) and / or a multi-bit correction (for example, ± 1 dB, ± 2 dB, ± 3 dB, ± 4 dB ,.). In addition, the UL power adjuster 206 (and / or the sector in the corresponding base station 202) can transmit the generated command to the access terminal for which the command is intended.

Furthermore, the access terminal or terminals can each be associated with a particular state at a particular time. Examples of access terminal states include LTE_IDLE, LTE_ACTIVE, and

ES 2 579 205 T3

LTE_ACTIVE_CPC. However, it will be appreciated 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. While in the LTE_IDLE state, the access terminal may lack a connection to the base station 202. Furthermore, the transition to the LTE_ACTIVE state from LTE_IDLe can be accomplished through the use of RACH.

LTE_ACTIVE is an access terminal state where the access terminal has a unique cell ID. Furthermore, when in the LTE_ACTIVE state, the access terminal can actively transfer data via the uplink and / or the downlink. Access terminals in this state have dedicated UL resources (eg cQi, SRS that are transmitted periodically, etc.). According to one example, the access terminals in the LTE_ACTIVE state may employ discontinuous transmission reception / discontinuous reception (DTX / DRX) procedures with a cycle that is not expected to be much greater than about 20 ms or 40 ms. Access terminals in this state initiate PUSCH transmissions directly in response to DL activity (eg, with the possibility of an in-band UL grant with DL data or via the PDCCH) or by sending a UL request on the PUCCH. Furthermore, the users in this state can be access terminals with active UL / DL data exchange taking place or access terminals running a high grade of service (GoS) application (for example, voice over internet protocol ( VoIP), ...).

LTE_ACTIVE_CPC (continuous packet connectivity) is a sub-state of LTE_ACTIVE where the access terminals retain their unique cell ID but where the dedicated UL resources have been released. Using LTE_ACTIVE_CPC allows you to extend the battery life. Access terminals in this sub-state initiate transmissions in response to DL activity (eg, possibly with an in-band UL grant with DL data or via the PDCCH, etc.) or by sending a UL request on the RACH. The initial transmit power can be based on an open loop mechanism (eg response to DL activity) or a last successful preamble (eg RACH).

Referring to FIG. 3, a system 300 is illustrated that periodically corrects an uplink power level employed by an access terminal. System 300 includes base station 202 that communicates with access terminal 302 (and / or any number of mismatched access terminals (not shown)). Access terminal 302 comprises a UL 304 power manager, further including a UL 306 power initiator. In addition, access terminal 302 includes a UL 308 periodic transmitter. Base station 202 further includes received power monitor 204 and UL power adjuster 206; the received power monitor 204 further comprises a periodic corrector 310.

Periodic corrector 310 generates periodic power control commands (eg, periodic transmit power control (TPC) commands, periodic corrections, etc.) to be transferred to access terminal 302. In addition, the periodic corrector 310 can transmit the periodic power control commands to the access terminal 302 (and / or any different access terminal or terminals) with any periodicity (eg, 0.5 ms, 1 ms, 2, ms , 4 ms, etc.); however, it is contemplated that the UL power adjuster 206 and / or the base station 202 may transmit such periodic power control commands. In addition, the periodic corrector 310 can produce a single-bit correction (eg, up / down, ± 1 dB, ...) and / or a multi-bit correction (eg, ± 1 dB, ± 2 dB, ± 3 dB, ± 4 dB ,.). For example, if the periodic corrections are sent from the periodic corrector 310 at a higher frequency, then it is more likely that single-bit corrections can 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 alter the uplink power level used for a transmission based on the commands obtained. According to another illustration, the UL 306 power initiator can establish an initial uplink transmit power. The UL 306 power initiator may employ an open loop mechanism to determine the initial uplink transmit power based on downlink activity, for example. Additionally, or alternatively, the UL 306 power initiator may map the initial uplink power level to a power level associated with a previous successful preamble (eg, immediately before, etc.) (eg, RACH).

The UL periodic transmitter 308 may send periodic transmissions on the uplink to the base station 202. For example, the UL periodic transmitter 308 may operate while the access terminal 302 is in the LTE_ACTIVE state. In addition, the periodic transmissions transferred by the UL 308 periodic transmitter may be a set of SRS transmissions; however, it will be appreciated that the claimed subject matter is not limited in this way, as any type of periodic uplink transmission may be employed (eg, periodic CQI transmissions, periodic PUCCH transmissions, etc.). Therefore, the UL periodic transmitter 308 can send SRS transmissions on the uplink to poll the channel across the entire bandwidth of the system, since SRS transmissions can be poll signals; therefore, while allowing selective uplink frequency programming, the polling signal can be used to calculate closed-loop corrections for UL power control. Transmissions sent by the periodic transmitter

ES 2 579 205 T3

UL 308 can be received and / or used by the received power monitor 204 of the base station 202 in connection with channel sampling. In addition, the UL power adjuster 206 and / or the periodic corrector 310 can generate commands corresponding to such samples.

According to an illustration, the periodicity of the UL transmissions sent by the UL periodic transmitter 308 from the access terminal 302 can be linked to the transmission cycle of the DL TPC command used by the periodic corrector 310 for the access terminal 302; therefore, access terminals with different UL transmission periodicity can send TPC DL commands with different transmission cycles. Furthermore, the periodicity of the UL transmissions can be related to various bits allocated for the access terminal power settings produced by the periodic corrector 310 employed for a particular access terminal (e.g., the access terminal 302, ...) . For example, an allocation may be predetermined between the number of bits allocated for uplink power control correction and an uplink periodic rate (eg, SRS rate, PUCCH rate ,.). Following this example, a 200 Hz uplink periodic transmission rate can be assigned in 1 bit, a 100 Hz rate can be assigned in 1 bit, a 50 Hz rate can be assigned in 2 bits, a 25 Hz rate can be assigned in in 2 bits, and a rate of 0 Hz can assign in x> 2 bits. According to the example mentioned above, the number of bits allocated for power settings in the access terminal becomes larger as the uplink periodic transmission rate decreases. At the limit for a 0 Hz uplink periodic transmission rate (for example, zero transmission of the SRS, PUCCH ,.), the power setting can be x> 2 bits, which can be the case for loop transmissions. open with closed loop adjustments as needed.

The periodic checker 310 may send corrections on a periodic basis to substantially all users in the LTE_ACTIVE state associated with the base station 202. According to one example, the users to whom the periodic checker 310 sends commands can be grouped based on, for example, on GoS requirements, DRX / DTX cycle and imbalance, etc. Transmission of the power control commands for the group of users can be done by the periodic corrector 310 in a particular instance of the PDCCH which can be represented by CPCCH or TPC-PDCCH. According to another illustration, the periodic editor 310 can use in-band signaling for a group of users, where the group size can be greater than or equal to 1. The overhead associated with the periodic correction may be based on a number of bits that the correction requires and the associated control (if any) required that carries the information to the relevant access terminals.

For the transfer of transmit power control commands (TPC) over the PDCCH via the periodic corrector 310, a 32-bit payload and an 8-bit CRC can be employed. For example, single 32-bit TPC commands can be used in a 1 ms interval for a PDCCH time. Therefore, 320 users can be supported in the LTE_ACTIVE state at 100 Hz using a single PDCCH in each TTI assuming FDD is used. Consequently, single-bit corrections can be provided every 10 ms, which can allow corrections of 100 dB / s. According to another example, double 16-bit TPC commands can be used in a 1 ms interval. Therefore, 320 users can be supported in the LTE_ACTIVE state with 50 Hz using a single PDCCH in each TTI assuming FDD is used. Therefore, double bit corrections every 20 ms allow corrections of 100 dB / s.

Turning now to FIG. 4, a system 400 is illustrated that aperiodically transfers power control commands to user terminals in an LTE-based wireless communication environment. System 400 includes base station 202 that communicates with access terminal 302 (and / or any number of different access terminals (not shown)). The base station 202 includes the received power monitor 204 and the UL power adjuster 206, which additionally comprises an aperiodic corrector 402. In addition, the access terminal 302 includes the Ul 304 power manager, which additionally includes an aperiodic command receiver 404.

The aperiodic corrector 402 can generate a power control command directed to the access terminal 302 as needed. For example, aperiodic corrector 402 may transmit aperiodic when triggered by a measurement (eg, measurement of a recognized condition using data from received power monitor 204, such as received power that is outside of a set range, etc.). The aperiodic corrector 402 can determine that an uplink power level of the access terminal 302 deviates from a target at a particular time; therefore, aperiodic corrector 402 may send a command to adjust this power level in response. In addition, the aperiodic corrector 402 can produce a single bit correction (eg, up / down, ± 1 dB, ...) and / or a multi-bit correction (eg, ± 1 dB, ± 2 dB, ± 3 dB, ± 4 dB ,.).

The aperiodic command receiver 404 can obtain the corrections sent by the aperiodic corrector 402 (and / or the UL power adjuster 206 and / or the corresponding sector in the base station 202 in general). For example, aperiodic command receiver 404 can decipher that a particular correction sent by the corresponding sector at base station 202 is destined for access terminal 302. Furthermore, based on the corrections obtained, the aperiodic command receiver 404 and / or the UL power manager 304 can alter an uplink power level employed by the access terminal 302.

The aperiodic corrections of the uplink power levels that are employed by the terminal of

ES 2 579 205 T3 access 302 and are produced by aperiodic corrector 402 can be based on the activator. Therefore, aperiodic corrections can be associated with higher overhead compared to periodic corrections due to the unicast nature of aperiodic corrections. Additionally, according to an example where multi-bit aperiodic corrections are employed, these corrections can be assigned in a particular instance of the PDCCH (for example, in which case the power correction can be transmitted as part of the DL assignment or UL grant) or a PDCCH / PDSCH pair (eg, in which case the power correction can be transmitted independently or in band with another data transmission).

Referring now to FIG. 5, a system 500 is illustrated that groups access terminals to send power control commands on a downlink. System 500 includes base station 202 that communicates with access terminal 1 502, access terminal 2 504, ..., and access terminal N 506, where N can be any integer. Each access terminal 502-506 may additionally include a respective UL power manager (for example, access terminal 1 502 includes a UL power manager 1 508, access terminal 2 504 includes a UL power manager 2 510, ., access terminal N 506 includes a UL power manager N 512). In addition, the corresponding sector in base station 202 may comprise received power monitor 204, UL power adjuster 206, and an access terminal (AT) grouper 514 that combines a subset of access terminals 502-506 into a group. to transmit power control commands on the downlink.

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

According to an illustration, the access terminal 1 502 can use a 200 Hz transmission rate for SRS transmission, the access terminal 2 504 can use a 50 Hz transmission rate for SRS transmission, and a Access N 506 can use a transmission rate of 100 Hz for an SRS transmission. The AT grouper 514 can recognize these respective transmission rates (eg, using signals obtained through the received power monitor 204 ,.). Subsequently, the AT grouper 514 can assign the access terminal 1 502 and the access terminal N 506 to a group A (along with any other access terminals that employ transmission rates of 100 Hz or 200 Hz). The AT bundler 514 may also assign the access terminal 2 504 (and any different access terminal employing 25 Hz or 50 Hz transmission rates) to a group B. However, it will be appreciated that the claimed subject matter is not limited to the illustration mentioned above. In addition, the AT grouper 514 may assign group IDs to each of the groups (eg, for use on the PDCCH or CPCCH). After the access terminals 502-506 have been assigned to the respective groups, the commands sent by the UL power adjuster 206 may employ downlink resources corresponding to a particular group associated with an intended receiver access terminal. For example, the AT grouper 514 and the UL power adjuster 206 can operate together to send TPC commands to multiple access terminals 502-506 on each PDCCH transmission. In addition, each UL 508-512 power manager may recognize an appropriate PDCCH transmission (s) to listen to to obtain the TPC command (s) directed thereto (eg, based on corresponding group IDs, etc.).

Returning to Figure 6, exemplary transmission structures are illustrated for communicating power control commands to groups of access terminals. For example, the transmission structures can be used for PDCCH transmissions. Two exemplary transmission structures are depicted (eg, transmission structure 600 and transmission structure 602); however, it is contemplated that the claimed subject matter is not limited to these examples. Transmission structures 600 and 602 can reduce overhead by grouping power control commands for multiple users on each PDCCH transmission. As illustrated, transmission structure 600 groups power control commands for users in group A in a first PDCCH transmission and power control commands for users in group B in a second PDCCH transmission. In addition, both the first and second PDCCH transmission include a cyclic redundancy check (CRC). In addition, the transmission structure 602 combines power control commands for users in groups A and B in a common PDCCH transmission. By way of illustration, for transmission structure 602, power control commands for users in group A can be included in a first segment of the common PDCCH transmission and power control commands for users in group B they can be included in a second segment of the common PDCCH transmission.

Referring to FIG. 7, an exemplary timing diagram 700 is illustrated for a periodic uplink power control procedure for LTE. At 702, power control procedures are illustrated for an access terminal in the LTE_ACTIVE state. In this state, the access terminal sends

ES 2 579 205 T3 periodic SRS transmissions to a base station, and the base station responds to periodic SRS transmissions with periodic TPC commands. As shown in the illustrated example, the transmission power of the access terminal is corrected for a single TPC bit transmitted periodically on the downlink. It will be appreciated that periodic SRS transmissions can be replaced by periodic CQI transmissions, periodic PUCCH transmissions, and the like. Periodic CQI transmissions or periodic PUCCH transmissions may be less efficient from a channel polling point of view since these transmissions may not span the entire system band; however, such transmissions can be leveraged for closed-loop corrections based on UL measurements at the base station.

At 704, an idle period is represented for the access terminal. After the inactivity period (eg, default use of a threshold period), the access terminal transmits to a LTE_ACTIVE_CPC sub-state. In this sub-state, the UL PHY resources are deallocated from the access terminal; therefore, it may not be possible to use closed-loop power control when UL transmissions are restarted.

At 706, the access terminal restarts the uplink transmissions. RACH is used to restart uplink transmissions using open loop estimation. According to an example, the open-loop estimate can be modified according to a last transmit power with some forgetting factor if it is considered beneficial. In response to the RACH sent by the access terminal, the base station may transmit an in-band power setting for the access terminal (eg, x-bit power setting, where x can be substantially any integer).

At 708, an identity of the access terminal can be verified through the RACH procedure. Also, the PHY UL resource reallocation can be done (eg in conjunction with SRS configuration) at 708.

At 710, the access terminal is in the LTE_ACTIVE state. Therefore, the access terminal restarts periodic SRS transmissions. As depicted, the periodicity of the periodic SRS transmissions at 710 differs from the periodicity of the periodic SRS transmissions at 702; however, the claimed subject matter is not limited in this way. In response to periodic SRS transmissions, the base station sends TPC commands that in this case represent 2 bits (eg, ± 1 dB, ± 2 dB). Also, although not illustrated, access terminal transmissions may continue to use open loop corrections determined from the receive power level at the access terminal. Therefore, the closed-loop corrections can be exclusive and / or greater than the open-loop corrections determined from changes in the reception power at the access terminal.

Now returning to FIG. 8, an exemplary timing diagram 800 is illustrated for an aperiodic uplink power control procedure for LTE. Power control procedures are illustrated for an access terminal in the LTE_ACTIVE state. Timing diagram 800 may lack periodic uplink transmissions. Furthermore, power corrections can be sent from a base station to the access terminal based on the power received by the PUSCH. The base station evaluates the PUSCH transmissions to determine whether to perform a power adjustment. Aperiodic power adjustments can be based on when the base station sends a message (e.g. TPC command in UL grant) to the access terminal if a power adjustment by the base station is deemed necessary after evaluating a particular PUSCH transmission. . When the base station determines that said power adjustment is not necessary at a particular time for a given PUSCH transmission, the base station does not need to transmit a TPC command at that time in response to the given PUSCH transmission (e.g. instead, an ACK may be transmitted in response to the determined PUSCH transmission, etc.). Furthermore, regardless of whether a TPC command is obtained by the access terminal at a certain time, the access terminal can constantly rely on corrections based on an open loop mechanism. Furthermore, the corrections sent by the base station can be single-bit corrections and / or multi-bit corrections.

It will be appreciated that a similar scheme can be employed with periodic UL transmissions when corrections can be sent on the DL as needed. Therefore, the access terminal can periodically send SRS transmissions on the uplink, which can be evaluated by the base station to determine the power settings to be made. Subsequently, after determining that a power adjustment is required at a particular time, the base station can send a TPC command over the downlink to the access terminal (e.g., an aperiodic downlink transmission of power control commands ).

The uplink power control procedures depicted in Figures 7 and 8 include commonalities. Specifically, the notion of APSD (Delta Power Spectral Density) used for UL data transmissions can be used for both periodic and aperiodic uplink power control. The APSD can provide a maximum transmit power that is allowed for a given user in order to minimize an impact on adjacent cells. The APSD can evolve over time depending on, for example, the load indicator of the adjacent cells, the channel conditions, etc. In addition, the APSD can inform the access terminal (eg, in-band) when possible. In LTE systems, the network can select which MCS / Max data-to-pilot ratio the access terminal is allowed to transmit. Without

However, the initial APSD may be based on the MCS in the UL grant (eg the relationship between the UL grant and the initial APSD may be formula based). Also, much of what has been mentioned above relates to inter-cell power control. Other mechanisms for inter-cell power control (eg, load control) may be complementary to the mechanisms described herein.

According to another illustration, the periodic and aperiodic uplink power control procedures can operate in combination. Following this illustration, periodic updates can be used on top of nonperiodic updates. If there are scheduled PUSCH transmissions, they may require corresponding PDCCH transmissions with the UL grant, and therefore power control commands can be transmitted on the PDCCHs with the UL grants. If the PDCCH is not available, for example, for persistent UL transmissions (for example, without requiring the UL grants since the pHy resources are configured by higher layers), then power control commands can be transmitted on the TPCPDDCH1. Also, if there is a PDSCH programmed in the DL, then the power control of the PUCCH (eg CQI and ACK / NAK) can be made more critical. In such a case, the power control commands for PUCCH can communicate on the PDCCHs with the DL assignments. For DL ​​transmissions without associated control or in the case of null DL data activity, periodic transmissions on TPC-DPCCH2 can be used to control PUCCH power. Consequently, power control commands can be transmitted when needed (e.g. aperiodic) while taking advantage of available resources (e.g. PDCCH with UL grants for PUSCH, PDCCH with DL assignments for PUCCH, periodic TPC commands in TPC-PDCCH which may be relevant for persistently scheduled PUCCH and PUSCH, etc.).

Referring to Figures 9-10, methodologies relating to uplink power control employing corrections in a wireless communication environment are illustrated. Although, in order to simplify the explanation, the methodologies are shown and described in a series of actions, it will be understood and appreciated that the methodologies are not limited by the order of actions, since certain actions may, according to one or more embodiments, occur in different orders and / or concurrently with other actions as shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology may alternatively be represented as a series of interrelated states or events, such as in a state diagram. Furthermore, not all the illustrated actions may be required to implement a methodology according to one or more embodiments.

Referring to FIG. 9, a methodology 900 is illustrated that facilitates the generation of power control commands in a wireless communication environment. At 902, uplink transmissions can be received from an access terminal. The uplink transmissions can be physical uplink shared channel (PUSCH) transmissions, for example. According to another illustration, the uplink transmissions may come from a set of periodic uplink transmissions sent by the access terminal; as such, periodic uplink transmissions can be polling reference signal (SRS) transmissions, channel quality indicator (CQI) transmissions, physical uplink channel (PUCCH) transmissions, and so on. At 904, a determination can be made as to whether to adjust an uplink power level employed by the access terminal. The uplink power level being analyzed is related to the uplink transmissions received. According to an example, the uplink power level can be compared to a target, and if the difference exceeds a threshold, then the adjustment can be activated; otherwise, if the difference is less than the threshold, then the adjustment does not need to be done at that time. In addition, an adjustment amount can be determined to the uplink power level of the access terminal. According to another illustration, a quality metric can be used to determine whether to adjust the uplink power level based on the construction of a bandwidth receive power or an estimate of the signal-to-noise ratio (SNR). from the collection of received uplink transmissions sent on the uplink by the access terminal (for example, the collection of received uplink transmissions may include periodically transmitted signals such as PUCCH, SRS, and the like, aperiodically transmitted signals such as PUSCH, etc.). If it is determined that adjustment with respect to the uplink power level is not necessary at 904, then the methodology 900 ends. If it is determined that the uplink power level should be set at 904, then the 900 methodology continues at 906. At 906, power control commands can be transmitted to the access terminal to alter the uplink power level using a layer 1 / layer 2 (L1 / L2) control information channel used for downlink (DL) assignments. and downlink grants (UL). For example, the transmission of power control commands can be triggered by a measurement (for example, measurement of the received power level that is outside a set range, etc.) or by the opportunity to transmit a power control command. (for example, by the transmission of a UL grant). Based on the determination at 904, power control commands can be sent as needed. Therefore, power control commands can be transmitted when needed and on an available channel (instead of a fixed preset location and channel). For example, power control commands can be sent on the PDCCH with DL assignments or UL grants a subset of times when available, and at other times, power control commands can be transferred on the TPC-PDCCH when is it availabe. Each power control command can be a single bit correction (for example, up / down, ± 1 dB, ...) and / or a multi-bit correction (for example, 0 dB, ± 1 dB,

ES 2 579 205 T3 ± 2 dB, ± 3 dB, ± 4 dB, ...). Furthermore, the power control command may be assigned in a particular instantiation of a physical downlink control channel (PDCCH) or a PDCCH / PDSCH (physical downlink shared channel) pair. In addition, the power control command can be transmitted independently or in band with other data transmissions. Additionally, for example, the power control command can be sent through a unicast transmission.

Power control commands can communicate in multiple places. Power control commands can be sent over a PDCCH with DL assignments or UL grants, for example. For example, power control commands can be sent over a PDCCH with DL assignments, which can be relevant to a PUCCh. In addition, power control commands can be transmitted over a PDCCH with UL grants, which can be relevant for a PUSCH. According to another illustration, power control commands can be sent over a PDCCH with power control commands for multiple access terminals (e.g., transmit power control-physical downlink control channel (TPC-PDCCH) ). As such, PDCCH can be the L1 / L2 control information channel (eg for LTE, ...). Therefore, a first TPC-PDCCH can be associated with a PUCCH and a second tPCPDCCH can be associated with a PUSCH (for example, which may be especially relevant for a persistently programmed PUSCH). As a further example, periodic uplink power level updates may be sent on periodic adjustments.

Returning to FIG. 10, a methodology 1000 is illustrated that facilitates the use of power control commands in a wireless communication environment. At 1002, data can be transmitted on a power level uplink. The data can be sent over a PUSCH, for example; therefore, the data can be transmitted periodically. According to a further example, the data transmission may be transmitted periodically (eg in relation to a set of periodic transmissions such as, for example, SRS transmissions, CQI transmissions, PUCCH transmissions, etc.). At 1004, a power control command may be received through a layer 1 / layer 2 (L1 / L2) control information channel used for downlink (DL) assignments and downlink (UL) grants. The power control command can be sent on a downlink upon the occurrence of a trigger condition or upon the opportunity to transmit a power control command (eg, due to the transmission of a UL grant). For example, the power control command can be transferred over the downlink when necessary and over an available channel as opposed to techniques where a fixed preset location and channel are used to communicate a power control command. Following this example, the power control command can be obtained on a PDCCH with DL assignments or UL grants first, while at a different time, the power control command can be received on a TPC-PDCCH. Furthermore, the power control command sent on the L1 / L2 control information channel can be generated in an eNode B receiver based on a construction of a wideband receive power or an estimate of the signal-to-noise ratio ( SNR) from a collection of signals transmitted on the uplink (eg data transmitted on the uplink at 1002). The power control command can be a single bit command and / or a multi-bit command. Furthermore, the power control command can be obtained through a PDCCH or a PDCCH / PDSCH pair. Additionally, the power control command can be received as a standalone or in-band transmission with other data transmitted from a base station. By way of further illustration, the power control command can be received at multiple locations; specifically, the power control command can be obtained on the PDCCH with DL assignments or UL grants and / or on the PDCCH with power control commands for multiple access terminals (eg, TPC-PDCCH). By virtue of this illustration, a power control command obtained through a PDCCH with DL assignments may be relevant to the PUCCH, and a power control command received through a PDCCH with UL grants may be relevant to the PUSCH. . According to another example, two TPC-PDCCH can be used: a first TPC-PDCCH can be used to provide PUCCh-relevant power control commands and a second TPC-PDCCH can be used to communicate PUSCH-relevant power control commands (e.g. example, which may be especially relevant for a persistently programmed PUSCH). In 1006, the power level can be altered based on the power control command. Furthermore, at a time when a power control command is not obtained, such alterations in the power level need not be made. According to another example, whether or not the power control command is received and used to adjust the power level, open loop power control mechanisms can be employed to alter the power level. At 1008, data can be transmitted on the uplink at the altered power level. In addition, data can be transmitted at a particular time and a first power level without receiving a power control command in response, and a next data transmission on the uplink can use the first power level. As a further example, periodic updates regarding the uplink power level may be received on aperiodic adjustments.

It will be appreciated that, in accordance with one or more aspects described herein, inferences can be made regarding the use of aperiodic power control commands. As used in this document, the term infer or inference generally refers to the reasoning process or the inference states of the system, environment and / or user from a set of observations made through events and / or data. Inference can be used to identify a specific context or action, or it can generate a probability distribution over states, for example. The inference can be probabilistic, that is,

ES 2 579 205 T3 the calculation of a probability distribution on states of interest based on a consideration of data and events. Inference can also refer to techniques used to create top-level events from a set of events and / or data. Such inference results in the generation of new events or actions from a set of observed events and / or stored event data, whether the events are correlated in close temporal proximity or not, and whether the events and data come from one or more data and event sources.

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

FIG. 11 is an illustration of an access terminal 1100 that facilitates the use of aperiodic power control commands in an LTE-based wireless communication system. Access terminal 1100 comprises a receiver 1102 that receives a signal from, for example, a receiving antenna (not shown), performs typical actions (eg, filters, amplifies, down-converts, etc.) on the received signal. 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 the received symbols and provide them to a processor 1106 for channel estimation. Processor 1106 may be a processor dedicated to analyzing the information received by receiver 1102 and / or generating information for transmission by a transmitter 1116, a processor that controls one or more components of the access terminal 1100, and / or a processor that analyzes information received by receiver 1102, generates information for transmission by transmitter 1116, and controls one or more components of access terminal 1100.

The access terminal 1100 may further comprise a memory 1108 that is operatively coupled to the processor 1106 and that can store data to be transmitted, received data, an identifier or identifiers assigned to the access terminal 1100, information related to aperiodic power control commands. obtained, and any other appropriate information to select whether to implement the aperiodic power control commands. Memory 1108 may additionally store protocols and / or algorithms associated with decryption if an aperiodic power control command is directed to access terminal 1100.

It should be appreciated that the data storage (eg, memory 1108) described herein may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. By way of illustration, and not by way of limitation, non-volatile 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 an external cache. By way of illustration, and not by way of 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 present systems and methods comprises, without being limited to, these and other suitable types of memory.

Additionally, receiver 1102 is operatively coupled to a UL power manager 1110 that controls a power level used by access terminal 1100 for transmission over an uplink. The UL 1110 power manager can adjust the uplink power level to transmit data, control signals, etc., over any type of uplink channel. The UL power manager 1110 may employ open loop mechanisms to select the uplink power level. Additionally, receiver 1102 and UL power manager 1110 can be coupled to aperiodic command receiver 1112 that evaluates aperiodic power control commands obtained by receiver 1102. Aperiodic command receiver 1112 deciphers when to listen to aperiodic power control commands directed towards access terminal 1100. In addition, the aperiodic command receiver 1112 determines that a particular aperiodic power control command is to be decoded, used, etc. In addition, the aperiodic command receiver 1112 (and / or the UL power manager 1110) alters the uplink power level used by the access terminal 1100 based on the aperiodic power control command. The access terminal 1100 still further comprises a modulator 1114 and a transmitter 1116 that transmits the signal to, for example, a base station, another access terminal, etc. Although the processor 1106 has been shown separately, it will be appreciated that the UL power manager 1110; an aperiodic command receiver 1112 and / or modulator 1114 may be part of processor 1106 or multiple processors (not shown).

Figure 12 is an illustration of a system 1200 that facilitates producing aperiodic power control commands in an LTE-based wireless communication environment. System 1200 comprises a base station 1202 (eg, access point, ...) with a receiver 1210 that receives a signal or signals from one or more

ES 2 579 205 T3 access terminals 1204 through a plurality of reference antennas 1206, and a transmitter 1222 transmitting to the one or more access terminals 1204 through a transmitting antenna 1208. Receiver 1210 can receive information from receiving antennas 1206 and is operatively associated with a demodulator 1212 that demodulates received information. The demodulated symbols are analyzed by a processor 1214 which may be similar to the processor previously described with respect to Figure 11, and which is coupled to a memory 1216 that stores information related to the access terminal identifiers (eg, MACIDs, etc.), data to be transmitted to or received from the access terminal (s) 1204 (or a different base station (not shown)) (for example, an aperiodic power control command or commands, etc.), and / or any other appropriate information related to the execution of the various actions and functions that are set forth in this document. Processor 1214 is further coupled to a received power monitor 1218 that evaluates the uplink power levels employed by an access terminal or terminals 1204 based on signals obtained at base station 1202. For example, received power monitor 1218 may analyze an uplink power level from a PUSCH transmission. According to another illustration, the received power monitor 1218 can evaluate an uplink power level of a periodic uplink transmission.

The received power monitor 1218 may be operatively coupled to an aperiodic corrector 1220 that alters the evaluated uplink power level (s) as needed. Adjustments made by aperiodic corrector 1220 can be triggered based on the occurrence of a predetermined condition, which can be identified based on a measurement. In addition, the aperiodic corrector 1220 can determine how much adjustment to make to the uplink power level (s) when such adjustments are deemed necessary. In addition, the aperiodic corrector 1220 can generate aperiodic power control commands that can subsequently be sent to the intended corresponding access terminal (s) 1204. The aperiodic corrector 1220 can additionally be operatively coupled to a modulator 1222. Modulator 1222 can multiplex aperiodic power control commands for transmission by transmitter 1226 through antenna 1208 to access terminal (s) 1204. Although separately illustrated to processor 1214, it should be appreciated that power monitor received 1218, aperiodic corrector 1220 and / or modulator 1222 may be part of processor 1214 or a plurality of processors (not shown).

Figure 13 shows an exemplary wireless communication system 1300. The wireless communication system 1300 represents a base station 1310 and an access terminal 1350 for the sake of brevity. However, it will be appreciated that the system 1300 may include more than one base station and / or more than one access terminal, wherein the additional base stations and / or access terminals may be substantially similar to or different from the base station. Exemplary access terminal 1310 and 1350 described below. Furthermore, it will be appreciated that base station 1310 and / or access terminal 1350 may employ the systems (Figures 1-5, 11-12, and 14-15) and / or procedures (Figures 9-10) described herein. document to facilitate wireless communication between them.

At base station 1310, traffic data for a plurality of data streams is provided from a data source 1312 to a transmitting data processor (TX) 1314. According to one example, each data stream may be transmitted through a respective antenna. The TX data processor 1314 formats, encodes, and interleaves the traffic data stream based on a particular encoding scheme selected for that data stream to provide encoded data.

The encoded 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 (FDM), 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 that can be used at the access terminal 1350 to estimate channel responses. The multiplexed pilot data and encoded data for each data stream can be modulated (eg, mapped with symbols) based on a particular modulation scheme (eg, binary phase shift keying (BPSK), phase shift keying quadrature (QPSK), M-ary phase shift keying (M-PSK), M-ary quadrature amplitude modulation (M-QAM), etc.) selected for that data stream to provide modulation symbols. The data transfer rate, encoding, and modulation for each data stream can be determined by instructions carried out or provided by a processor 1330.

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

Each 1322 transmitter 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 channel. MIME.

ES 2 579 205 T3

Furthermore, Nt modulated signals from transmitters 1322a to 1322t are transmitted from Nt antennas 1324a to 1324t, respectively.

At the access terminal 1350, the transmitted modulated signals are received by Nr antennas 1352a to 1352r and the received signal from each antenna 1352 is provided to a respective receiver (RCVR) 1354a to 1354r. Each receiver 1354 conditions (eg, 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 symbol streams received from Nr receivers 1354 based on a particular receiver processing technique to provide Nt detected symbol streams. The RX 1360 data processor can demodulate, deinterlace and decode each detected symbol stream to recover the traffic data for the data stream. The RX 1360 data processor processing is complementary to that performed by the TX 1320 MIMO processor and the TX 1314 data processor in the base station 1310.

A 1370 processor can periodically determine what available technology to use as discussed above. Additionally, processor 1370 may formulate a reverse link message that comprises an array index portion and a range value portion.

The reverse link message may comprise various types of information related to the communication link and / or the received data flow. The reverse link message can be processed by a TX data processor 1338, which also receives traffic data for a plurality of data streams from a data source 1336, modulated by a modulator 1380, conditioned by transmitters 1354a to 1354r, and sent to base station 1310.

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

Processors 1330 and 1370 can direct (eg, control, coordinate, manage, etc.) the operation of base station 1310 and access terminal 1350, respectively. The respective processors 1330 and 1370 may be associated with memories 1332 and 1372, which store codes and program data. Processors 1330 and 1370 can also perform calculations to obtain frequency and pulse response estimates for the uplink and downlink, respectively.

It should be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For a hardware implementation, the processing units can be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, 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 may be stored on a machine-readable medium, such as a storage component. A code segment can represent a procedure, function, subprogram, program, routine, subroutine, module, software package, class, or any combination of instructions, data structures, or program statements. A code segment can be coupled to another code segment or to a hardware circuit by passing and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc., can 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 can be implemented with modules (eg, procedures, functions, etc.) that carry out the functions described herein. Software codes can be stored in memory units and executed by processors. The memory unit can be implemented in the processor or external to the processor, in which case it can be communicatively coupled to the processor through various means, as is known in the art.

Referring to FIG. 14, a system 1400 is illustrated that allows power control commands to be produced for use by access terminals in a wireless communication environment. For example, the system 1400 can reside at least partially in a base station. It should be appreciated that the system 1400 is represented as including functional blocks that may be functional blocks that represent functions implemented by

ES 2 579 205 T3 a processor, software or a combination thereof (eg firmware). System 1400 includes a logical grouping 1402 of electrical components that can act together. For example, logical array 1402 may include an electrical component to obtain uplink transmissions sent from an access terminal at uplink power level 1404. In addition, logical grouping 1402 may comprise an electrical component to evaluate whether to alter the uplink power level employed by access terminal 1406. In addition, logical grouping 1402 may include an electrical component for sending power control commands through an L1 / L2 control information channel used for downlink (DL) assignments and downlink (UL) grants, where the Power control commands adjust the uplink power level by a specified amount 1408. For example, power control commands can be generated and transmitted as needed. In addition, system 1400 may include memory 1410 that stores instructions to perform functions associated with electrical components 1404, 1406, and 1408. Although displayed external to memory 1410, it should be understood that one or more of electrical components 1404, 1406 and 1408 may exist within memory 1410.

Returning to FIG. 15, a system 1500 is illustrated that enables power control commands to be produced in a wireless communication environment. System 1500 can reside in an access terminal, for example. As depicted, the system 1500 includes functional blocks that may represent functions implemented by a processor, software, or a combination thereof (eg, firmware). System 1500 includes a logical grouping 1502 of electrical components that can act together. Logical grouping 1502 may include an electrical component to send data on an uplink at a power level 1504. Additionally, logical grouping 1502 may include an electrical component to obtain a power control command through an L1 / L2 control information channel used for downlink (DL) assignments and downlink (UL) grants 1506. Additionally, logical array 1502 may include an electrical component to change the power level for subsequent data transmission based on power control command 1508. According to another illustration, the power level can be changed, additionally or alternatively, for subsequent data transmission based on an open loop power control mechanism. Additionally, system 1500 may include memory 1510 that stores instructions to perform functions associated with electrical components 1504, 1506, and 1508. Although shown external to memory 1510, it should be understood that electrical components 1504, 1506, and 1508 may exist within memory 1510.