Priority-based transmit power control

Certain aspects of the present disclosure provide techniques for priority-based transmit power control. A method that may be performed by a user equipment (UE) includes communicating with at least a second UE via a link, determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information, and outputting the information for transmission via the link in accordance with the determined transmission power.

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for priority-based transmit power control.

Description of Related Art

SUMMARY

Certain aspects provide a method for wireless communications by a first user equipment (UE). The method generally includes communicating with at least a second UE via a link, determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information, and outputting the information for transmission via the link in accordance with the determined transmission power.

Certain aspects provide an apparatus for wireless communications by a first user equipment (UE). The apparatus generally includes a processing system configured to communicate with at least a second UE via a link and determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information. Additionally, the apparatus generally includes an interface configured to output the information for transmission via the link in accordance with the determined transmission power.

Certain aspects provide an apparatus for wireless communications by a first user equipment (UE). The apparatus generally includes means for communicating with at least a second UE via a link, means for determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information, and means for outputting the information for transmission via the link in accordance with the determined transmission power.

Certain aspects provide a user equipment (UE) for wireless communications. The UE generally includes a processing system configured to communicate with at least a second UE via a link and determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information. Additionally, the UE generally includes a transmitter configured to output the information for transmission via the link in accordance with the determined transmission power.

Certain aspects provide a non-transitory computer-readable medium for wireless communications by a first user equipment (UE). The non-transitory computer-readable medium generally includes instructions that, when executed by at least one processor, cause the at least one processor to communicate with at least a second UE via a link, determine a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information, and output the information for transmission via the link in accordance with the determined transmission power.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for priority-based transmit power control. In some cases, the techniques presented herein may be applied to side-link communication links between user equipments (UEs) as well as other communication links, such as access links between a UE and a base station (BS).

FIG.1illustrates an example wireless communication network100in which aspects of the present disclosure may be performed. For example, the wireless communication network100may be an NR system (e.g., a 5G NR network).

According to certain aspects, the BSs110and UEs120may be configured for priority-based transmit power control. For example, as shown inFIG.1, the UE120aincludes a power control module122. The power control module122may be configured to communicate with at least a second UE via a link, determine a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information, and output the information for transmission via the link in accordance with the determined transmission power, in accordance with aspects of the present disclosure. In some examples, the power control module122may select a power control compensation factor based on the priority corresponding to the information and determine the transmission power using the selected power control compensation factor, as described below.

Wireless communication network100may also include relay stations (e.g., relay station110r), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS110aor a UE120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE120or a BS110), or that relays transmissions between UEs120, to facilitate communication between devices.

A network controller130may couple to a set of BSs110and provide coordination and control for these BSs110. The network controller130may communicate with the BSs110via a backhaul. The BSs110may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

FIG.2illustrates example components of BS110aand UE120a(e.g., in the wireless communication network100ofFIG.1), which may be used to implement aspects of the present disclosure.

At the BS110a, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. The processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor220may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor230may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)232a-232t. Each modulator232may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators232a-232tmay be transmitted via the antennas234a-234t, respectively.

The memories242and282may store data and program codes for BS110aand UE120a, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

The controller/processor280and/or other processors and modules at the UE120amay perform or direct the execution of processes for the techniques described herein. For example, as shown inFIG.2, the controller/processor280of the UE120amay include a power control module281that may be configured for priority-based transmit power control, according to aspects described herein. For example, in some cases, the power control module281may be configured to communicate with at least a second UE via a link, determine a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information, and output the information for transmission via the link in accordance with the determined transmission power Although shown at the Controller/Processor, other components of the UE120aand BS110amay be used performing the operations described herein.

Example Priority-Based Transmit Power Control

In certain wireless communication networks, such as the wireless communication network100, a user equipment (UE) may communicate with different nodes in the wireless communication network using various communication links. For example, in some cases, as illustrated inFIG.3, UE1may communicate one or more base stations305(e.g., gNBs) in the network using one or more access-links304. Additionally, in some cases, UE1may communicate (e.g., directly) with one or more other UEs (e.g., UE2) via one or more side-links306.

In some cases, when UEs transmit to each other on the side-link, these UEs may need to take in to consideration the interference that the sidelink transmissions can cause on the access links or other side-links in the wireless communication network. For example, as illustrated inFIG.3, UE1may communicate with UE2via side-link306using one or more transmission beams, such as main lobe308. However, as illustrated, during transmission other side lobes may radiate power in directions other than towards the UE2, potentially causing interference to other side-links and access-links in the wireless communication network. For example, as illustrated, during transmission on side-link306, side lobes310and312may radiate power in a direction other than towards UE2, causing interference to access link304and side-link314, respectively.

Thus, as noted above, when transmitting on a side-link, a UE may take into consideration the interference that the sidelink transmissions can cause on the access links or other side-links. In some cases, to reduce interference that side-link transmissions can cause on the access links or other side-links, a UE may be configured to perform open loop power control to adjust the transmission power of the side-link transmissions, taking into account a priority associated with the information to be transmitted via the side link. For example, for certain types of information/traffic (e.g., high priority information) transmitted on the side-link it may be permissible to cause interference to other communication links in the wireless communication network as opposed to other types of information (e.g., low priority information).

Thus, aspects of the present disclosure provide techniques for mitigating interference caused by side-link transmissions while also taking into account the priority associated with the information to be transmitted via the side-link. More specifically, aspects of the present disclosure provide techniques for priority-based transmit power control.

FIG.4is a flow diagram illustrating example operations400for wireless communication, in accordance with certain aspects of the present disclosure. The operations400may be performed, for example, by a first UE (e.g., such as a UE120ain the wireless communication network100). Operations400may be implemented as software components that are executed and run on a processing system, including one or more processors (e.g., controller/processor280ofFIG.2). Further, the transmission and reception of signals by the UE in operations400may be enabled, for example, by one or more antennas (e.g., antennas252ofFIG.2). In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller/processor280) obtaining and/or outputting signals.

The operations400may begin, at402, by communicating with at least a second UE via a link. In some cases, the link may comprise a side-link between the first UE and the second UE. In some cases, communicating with at least the second UE via the link may include establishing the link with the second UE. Additionally, in some cases, the UE may also communicate with one or more base stations via at least one access-link.

At404, the UE determines a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information.

At406, the UE outputs the information for transmission via the link in accordance with the determined transmission power. Additionally, while not illustrated, operations400may also include transmitting the information via the link in accordance with the determined transmission power.

As noted above, aspects of the present disclosure provide techniques for priority-based transmit power control. In certain cases, a UE may already be configured to perform power control on an access link shared between a base station and itself.

For example,FIG.5illustrates an exemplary access-link power control formula used to determine a transmission power for transmitting information on the access-link. As illustrated, the transmission power for the access link may take into account a plurality of parameters, such as a maximum UE power (e.g., PCMAX), a number of resource blocks associated with an uplink channel transmitted on the access link (e.g., 10 log10(MPUSCH(i))), a target receive power at the base station (e.g., PO_PUSCH), a path loss associated with the access link (e.g., PL), a power control compensation factor associated with the path loss (e.g., α(j)), a transmission formation/modulation and coding scheme (e.g., ΔTF(i)), and closed loop power control (e.g., f(i)). In some cases, the power control compensation factor, alpha (α), is introduced to compensate for PL observed on the access-link and may be a value between 0 and 1. For example, in some cases, alpha may be set low if the transmission by the UE cause significant interference to other receivers; otherwise, alpha may be set high to fully compensate for PL.

According to aspects, side-link data packets may have different proximity service (Prose) priority. For example, in some cases, certain data like public safety data have high priority, while other data have low priority. Additionally, in some cases, high priority transmissions like for public safety tend to benefit more users and, thus, may be transmitted at higher power to reach more UEs. According to aspects, the benefit of transmitting a high priority packet at a higher power may be worth the potential increase in interference to other connection links in a wireless communication network. Further, other types of data, such as low-priority data may be transmitted at a lower power so as to reduce interference to other connection links in the wireless communication network.

Thus, as noted above, aspects of the present disclosure provide techniques for determining a transmission power for side-link connections, for example, based, at least in part, on a priority corresponding to information to be transmitted on the side-link connection.

For example, as noted above, a first UE may communicate with at least a second UE via a link, such as a side-link connection. For example, in some cases, the first UE may communicate with the second UE to establish the side-link connection

The UE may then determine a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information. According to aspects, the UE may then output the information for transmission on the link according to the determined transmission power.

In some cases, the priority corresponding to the information may be based on a type of the information. For example, in some cases, the type of the information comprises at least one of emergency services information or public safety information (or the like). In this case, the priority corresponding to the information may be “high.” Further, in some cases, the type of the information comprises at least one of navigation information, group-cast information, or traffic flow management information (or the like). In this case, the priority corresponding to the information may be “medium.” Additionally, in some cases, the type of the information comprises at least one of gaming information, media content sharing information, or advertisement information (or the like). In this cases, the priority corresponding to the information may be “low.”FIG.6illustrates an exemplary table showing different information types and corresponding priorities. Additionally,FIG.6shows a power control compensation factor corresponding to the various information types, which is explained in greater detail below.

According to aspects, based on the priority corresponding to the information to be transmitted on the side link, the UE may also select a power control compensation factor (e.g., alpha) and use the power control compensation factor to determine the transmission power (e.g., in some cases, using a transmission power formula similar toFIG.5). For example, in some cases, the UE may determine that information needs to be transmitted over the side link and may determine a type of the information. Thereafter, based on the determined type of information, the UE may determine the priority corresponding to the information.

Additionally, based on the determined priority, the select an appropriate power control compensation factor to be used when determining the transmission power for transmitting the information via the link. As noted,FIG.6illustrates power scaling factors corresponding to different types of information with different priorities. According to aspects, as illustrated, the higher the priority corresponding to the information is the higher the selected power control compensation factor is. For example, as illustrated, high priority information may correspond to a higher power control compensation factor of 1 while low priority information may correspond to a lower power control compensation factor of 0.25. It should be understood that these exact power scaling values are not meant to be restrictive and are meant only for illustrative purposes.

In some cases, selection of the power control compensation factor may also be based on an operating mode of the UE, such as in coverage mode or out of coverage mode. For example, in some cases, when alpha<1, a modulation and coding scheme (MCS) may be reduced so that the information is transmitted correctly, thus the MCS-related offset in the power-control equation illustrated inFIG.5may be ‘turned off’. In case of sidelink, if the UE is operating in in coverage mode and gNB controls the side-link MCS then the same can apply (e.g., the MCS-related offset may be “turned off”). However, if the UE is operating in out of coverage mode where the UE controls the sidelink MCS then “turning off” the MCS-related offset may not be needed. Thus, in certain cases, a transmission power cap (e.g., similar txpower effect) could be effectively achieved by using either alpha=1 with much reduced MCS or with alpha<1 with a somewhat reduced MCS. Thus, in certain cases, the selection of the power control compensation factor, alpha, may be based on an operating mode of the UE. Additionally, in some cases, the UE may be further configured to determine a modulation and coding scheme (MCS) based on the operating mode of the UE and the selected power scaling factor. The determined MCS may then also be used for transmitting the information on the link.

Additionally, alpha<1 may imply more and more “deficit in Txpower” (to be made up by reducing MCS) as UE goes towards cell-edge (and is thus more likely to interfere with neighbor cell). However, for the side-link, this increase in “Txpower deficit” happens as the side-link transmitter and receiver get further from each other, which in general is not the same as side-link transmitter getting nearer to cell-edge. So, the fractional alpha scheme may also result in unnecessarily low transmit power if the intent was to reduce the neighbor-cell interference. Thus, the use of the alpha*PL term (e.g., as illustrated inFIG.5) may also depend on PLs measured to other potential targets (like serving gNB or other sidelink UEs that do not need to receive this side-link transmitter's transmission). Thus, in some cases, selection of the power control compensation factor may be based on/associated with path loss measurements, such as path loss measurements associated with one or more other UEs and one or more base stations, for example, such as illustrated inFIG.3.

FIG.7illustrates a communications device700that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated inFIG.4. The communications device700includes a processing system702coupled to a transceiver708. The transceiver708is configured to transmit and receive signals for the communications device700via an antenna710, such as the various signals as described herein. The processing system702may be configured to perform processing functions for the communications device700, including processing signals received and/or to be transmitted by the communications device700.

The processing system702includes a processor704coupled to a computer-readable medium/memory712via a bus706. In certain aspects, the computer-readable medium/memory712is configured to store instructions (e.g., computer-executable code) that when executed by the processor704, cause the processor704to perform the operations illustrated inFIG.4, or other operations for performing the various techniques discussed herein for priority-based transmit power control. In certain aspects, computer-readable medium/memory712stores code714for communicating with at least a second UE via a link; code716for determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information; code717for outputting the information for transmission via the link in accordance with the determined transmission power; code718for selecting a power control compensation factor based on the priority corresponding to the information; and code719for determining a modulation and coding scheme (MCS) based on the operating mode of the UE and the power control compensation factor. Additionally, while not illustrated, computer-readable medium/memory712may also store code for performing other operations related to priority-based transmit power control described herein. In certain aspects, the processor704includes circuitry configured to implement the code stored in the computer-readable medium/memory712. For example, processor704includes circuitry720for communicating with at least a second UE via a link; circuitry722for determining a transmission power for transmitting information via the link based, at least in part, on a priority corresponding to the information; circuitry724for outputting the information for transmission via the link in accordance with the determined transmission power; circuitry726for selecting a power control compensation factor based on the priority corresponding to the information; and circuity728for determining a modulation and coding scheme (MCS) based on the operating mode of the UE and the power control compensation factor. Additionally, while not illustrated, processor704may also include circuitry for performing other operations related to priority-based transmit power control described herein.

The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, . . . slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. In some examples, MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. In some examples, multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.