Patent Description:
<NPL>, relates to digital pre-distortion (DPD) training for an equipment which is enabled with simultaneous transmission in two networks, for example WCDMA and LTE (dual band architecture).

Advantageous embodiments are subject to the dependent claims.

In the following, each of the described methods, apparatuses, systems, examples and aspects, which does not fully correspond to the invention as defined in the appended claims, is thus not according to the invention and is, as well as the whole following description, present for illustration purposes only or to highlight specific aspects or features of the appended claims.

Characteristics of concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures.

It should be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

A BS is an entity that communicates with user equipments (UEs) and may also be referred to as a base station, a NR BS, a Node B, a gNB, a <NUM> node B (NB), an access point, a transmit receive point (TRP), and/or the like. In some aspects, the network <NUM> may be a licensed network. For example, the network <NUM> may require a license or subscription to permit a UE <NUM> to communicate with BS <NUM>.

UE <NUM> may include a modem. For example, one or more components of UE <NUM> (e.g., of antenna <NUM>, modulator <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, and/or the like) may form or be included within a modem of the UE <NUM> that is used to transmit a signal to BS <NUM>. In some aspects, UE <NUM> may include a mixer that enables UE <NUM> (e.g., the modem) to transmit and/or receive signals at different frequencies or to switch between bands of communication (e.g., between a <NUM> band and a Wi-Fi band). Accordingly, the UE <NUM> and/or a modem of the UE <NUM> may facilitate communication between UE <NUM> and multiple networks that use different bands.

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with performing digital pre-distortion (DPD) training using a secondary network, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG> and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively.

In some aspects, UE <NUM> may include means for determining that a DPD training is to be performed by a modem, wherein the modem is configured to facilitate communication between the UE and a primary network associated with the UE; means for configuring the modem to perform the DPD training using a secondary network associated with the UE; and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>.

In many instances, a UE includes a transmitter path with one or more non-linear components, such as an amplifier (e.g., a high power amplifier (HPA)), with limited dynamic range (DR), that distorts the transmitted signal due to a high peak to average power ratio (PAPR). For example, one or more of antenna <NUM>, modulator <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, and/or the like may include an HPA that distorts the transmitted signal. A power back-off (BO) may be implemented to address the distortions; however, use of a power BO may result in less power efficiency of the UE as the greater the power BO that is applied, the less power that is transmitted to the channel. In some instances, the one or more components along the transmitter path of the UE may perform digital pre-distortion (DPD) to address the distortion of the transmitted signal. Using the DPD, non-linearity in the transmitted signal is addressed and the need for a power BO is reduced.

In some instances, distortion or non-linearity of the transmitted signal can vary based at least in part on the temperature (or temperature changes) of the UE. As a consequence, DPD training may be performed while the UE is online (e.g., in communication with wireless network <NUM>) when a temperature change occurs and/or when the UE is scheduled to properly configure the DPD to address the non-linearity of the transmitted signal. During the DPD training, a modem of the UE transmits a signal at high power and loops back the transmitted signal (e.g., over the air, using an internal leakage mechanism, and/or the like) to determine the differences between the transmitted signal and the loopback signal. Based on the differences between the transmitted signal and the loopback signal, the UE may configure a DPD to address the non-linearities along the transmission path.

The UE, when performing the DPD training while online or in communication with a BS, may be limited to using resources associated with an allocated grant from the BS (e.g., BS <NUM>). In some instances, the BS may not allocate uplink resources or information in a desired amount of time to enable the UE to perform the DPD training and/or may not allocate sufficient bandwidth for the UE to perform the DPD training effectively. Furthermore, in some instances, the signal transmitted during the DPD training may be affected by a poor error vector magnitude (EVM) caused by HPA non-linearities being unaddressed, which leads to likely retransmission and loss of spectral efficiency.

Some aspects described herein provide DPD training that uses a secondary network (e.g., an unlicensed network) to enable the UE (or a user associated with the UE) to select transmission timing and/or a transmission waveform for the DPD training. Accordingly, in some aspects described herein, the UE is not limited to using a configuration as determined by a BS, but rather, the configuration can be set by the UE. Accordingly, some aspects described herein may provide enhanced DPD training by ensuring that the DPD training can be timely and accurately performed. Therefore, some aspects of the present disclosure may conserve resources (e.g., network resources, processing resources, and/or the like) associated with performing DPD training. For example, network resources may be conserved by avoiding the need to perform one or more subsequent DPD trainings due to insufficient bandwidth. Furthermore, network resources may be conserved by avoiding the need to retransmit signals because the DPD was not properly adjusted in a timely manner (e.g., due to the BS not communicating a grant for the DPD training in time and thus the DPD training not being performed). Moreover, some aspects described herein conserve processing resources associated with performing the one or more subsequent DPD trainings and/or retransmitting signals.

<FIG> is a diagram illustrating an example <NUM> of performing digital pre-distortion (DPD) training using a secondary network, in accordance with various aspects of the present disclosure. Example <NUM> of <FIG> includes a UE <NUM>, a cellular network <NUM> (which may be referred to herein as a "primary network" or a "licensed network"), such as an NR network (e.g., <NUM> network), an LTE network, and/or the like, and a Wi-Fi network <NUM> (which may be referred to herein as a "secondary network" or an "unlicensed network"). Using previous techniques, when performing a DPD training, UE <NUM> may be limited to a configuration provided by a BS <NUM> of cellular network <NUM>, which is a licensed network of UE <NUM>. Some aspects described herein enable UE <NUM> to configure DPD training settings (e.g., transmission timing, transmission bandwidth, and/or the like) using the Wi-Fi network, which may be an unlicensed network.

As shown in <FIG>, and by reference number <NUM>, UE <NUM> establishes a communication session with cellular network <NUM>. For example, UE <NUM> may establish a communication session with a BS <NUM> of cellular network <NUM>. In some aspects, the communication session is a licensed communication session that is authorized by a subscription and/or agreement that UE <NUM> is capable of communicating with cellular network <NUM> and/or via cellular network <NUM>. Accordingly, in some aspects, cellular network <NUM> may be considered a primary network that UE <NUM> uses for communication.

As further shown in <FIG>, and by reference number <NUM>, UE <NUM> determines that DPD training is to be performed and configures a modem of UE <NUM> to perform the DPD training using Wi-Fi network <NUM>. In some aspects, UE <NUM> may determine that DPD training is to be performed based on a schedule and/or an event indicating that the DPD training is to be performed. For example, DPD training may be scheduled to be performed periodically (e.g., every minute, every five minutes, and/or the like). Additionally, or alternatively, UE <NUM> may be configured to monitor one or more characteristics of UE <NUM> and/or events associated with UE <NUM> to determine whether to perform DPD training. For example, UE <NUM> may monitor a temperature associated with UE <NUM> (e.g., an internal temperature, a temperature of one or more components of UE <NUM>, an external temperature, and/or the like). In such cases, when UE <NUM> determines that the temperature changes a threshold amount (e.g., one degree, five degrees, and/or the like), the UE <NUM> may determine that DPD training is to be performed based on the temperature change. Additionally, or alternatively, UE <NUM> may monitor other characteristics (e.g., transmitter power, battery power, and/or the like) and determine that DPD training is to be performed based on the other characteristics or a threshold change to the other characteristics.

UE <NUM> configures a modem to perform the DPD training via Wi-Fi network <NUM> by switching a mixer of the UE <NUM> from a band of cellular network <NUM> (e.g., an LTE band, a <NUM> band, and/or the like) to a band of Wi-Fi network <NUM>. When configuring the modem to perform the DPD training, UE <NUM> selects a transmission timing (e.g., when the DPD training signal is to be transmitted and/or looped back) and, in some cases, also a transmission waveform (e.g., bandwidth, transmission power, and/or the like) for the DPD training using the Wi-Fi network. For example, UE <NUM> may select the transmission timing and/or transmission waveform based at least in part on a user input, based at least in part on a specification of UE <NUM> and/or Wi-Fi network <NUM>, based at least in part on one or more characteristics of UE <NUM> (e.g., temperature, transmission power capabilities, remaining battery power, and/or the like) of the UE <NUM>, and/or the like. Accordingly, UE <NUM> may select the transmission timing for the DPD training and switch the mixer to a band of Wi-Fi network <NUM> to perform the DPD training. In some aspects, UE <NUM> may include a single modem that may be used to access cellular network <NUM> and Wi-Fi network <NUM> or a plurality of separate modems to access cellular network <NUM> and Wi-Fi network <NUM>. For example, a first one of the plurality of modems may be used to access cellular network <NUM> and a second one of the plurality of modems may be used to access Wi-Fi network <NUM>.

The band of Wi-Fi network <NUM> may have sufficient bandwidth to enable UE <NUM> to perform the DPD training using Wi-Fi network <NUM>. For example, to perform a sub-<NUM><NUM> DPD training (e.g., an NR DPD training where the used spectrum is below <NUM>), Wi-Fi network <NUM> may have up to a threshold bandwidth (e.g., <NUM>) to perform the sub-<NUM><NUM> DPD training.

As further shown in <FIG>, and by reference number <NUM>, UE <NUM> performs the DPD training using Wi-Fi network <NUM>. UE <NUM> may use any suitable technique to perform the DPD training. For example, UE <NUM> may transmit a signal via a band of Wi-Fi network <NUM> and loop back the signal (e.g., over the air and/or through an internal leakage mechanism). Accordingly, the DPD training can be performed using Wi-Fi network <NUM> and/or any other secondary or unlicensed network available to UE <NUM>. The DPD training is used to address non-linearities within transmitted signals from UE <NUM>.

As further shown in <FIG>, and by reference number <NUM>, UE <NUM> resumes (or continues) the communication session with cellular network <NUM>. In some aspects, the communication session and/or communications between UE <NUM> and cellular network <NUM> are paused, discontinued, and/or the like while the UE <NUM> performs the DPD training. In some aspects, the communication session between UE <NUM> and cellular network <NUM> is not paused or discontinued while the DPD training is performed via Wi-Fi network <NUM>. Accordingly, UE <NUM> may perform the DPD training using Wi-Fi network <NUM> during the communication session with cellular network <NUM>. UE <NUM> is configured to determine that UE <NUM> is not scheduled to transmit a communication via cellular network <NUM> (e.g., via a licensed band) and switch to a band of Wi-Fi network <NUM> to perform the DPD training. In such cases, the communication session between UE <NUM> and cellular network <NUM> may not be broken. In some aspects, after performing the DPD training using Wi-Fi network <NUM> is complete, to resume the communication session, UE <NUM> (and/or a modem of UE <NUM>) switches a mixer from a band of Wi-Fi network <NUM> back to a band of cellular network <NUM>. In some aspects, if UE <NUM> determines that DPD training is to be performed and is scheduled to communicate with cellular network <NUM>, UE <NUM> may perform the DPD training during the scheduled communication with cellular network <NUM>.

Accordingly, UE <NUM> may have adjusted a DPD of UE to address non-linearities or distortions in the transmitted signals. As a result, UE <NUM> may conserve processing resources, network resources, and/or power resources associated with transmitting signals.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a UE (e.g., UE <NUM>) performs DPD training using a secondary network.

As shown in <FIG>, process <NUM> includes determining that a digital pre-distortion (DPD) training is to be performed by a modem, wherein the modem is configured to facilitate communication between the UE and a primary network associated with the UE (block <NUM>). For example, UE <NUM> (e.g., using transmit processor <NUM>, TX MIMO processor <NUM>, controller/processor <NUM>, and/or the like) may determine that the DPD training is to be performed. In some aspects, UE <NUM> may determine that the DPD training is to be performed based at least in part on monitoring one or more characteristics of UE <NUM>, based on a schedule to perform DPD training, and/or the like.

As further shown in <FIG>, process <NUM> includes configuring the modem to perform the DPD training using a secondary network associated with the UE (block <NUM>). For example, UE <NUM> (e.g., using transmit processor <NUM>, TX MIMO processor <NUM>, controller/processor <NUM>, and/or the like) may configure the modem of UE <NUM> to perform the DPD training via Wi-Fi network <NUM>. In some aspects, UE <NUM> may configure the modem to perform the DPD training based at least in part on determining that the modem is to perform the DPD training. The modem is configured to select a transmission timing for the DPD training, switch a mixer of the modem to a band of the secondary network, perform the DPD training, and switch the mixer of the modem back to a band of the primary network.

Claim 1:
A method of wireless communication performed by a user equipment, UE, comprising:
determining (<NUM>) that a digital pre-distortion, DPD, training is to be performed by a modem, wherein the modem is configured for communication between the UE and a primary network associated with the UE; and
configuring (<NUM>) the modem to perform the DPD training using a secondary network associated with the UE, wherein the modem is configured to select a transmission timing for the DPD training, to switch a mixer of the modem to a band of the secondary network, and to perform the DPD training, and
configuring the modem to switch the mixer of the modem back to a band of the primary network to resume communication between the UE and the primary network using the DPD training to address non-linearities within transmissions by the UE.