Patent Description:
International patent application <CIT> discloses a method for wireless communication wherein a terminal device determines, according to N first ports used by a first channel or a first signal in a first time unit, M second ports used by a second channel or a second signal in the first time unit and sends, in the first time unit, the first channel or the first signal via the N first ports, and then sends, in the first time unit, the second channel or the second signal via the M second ports.

<NPL>" discloses reserving a guard period between PUSCH transmission and transmission of SRS if an indicated SRS Resource Indicator (SRI) of the PUSCH transmission is different from the following SRS in the SRS set for codebook.

<NPL>" teaches SRS antenna switching with carrier switching based on a predefined pattern.

The present disclosure provides a method of selecting an antenna configuration according to claim <NUM> and a user equipment according to claim <NUM>. Specific embodiments are subject of the dependent claims.

It is to 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.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for selectively scheduling guard periods for user equipments with multiple antennas.

For example, the wireless communication network <NUM> may be a New Radio (NR) or <NUM> network. In some examples, network <NUM> may be configured to implement methods as described below with respect to <FIG> and 9A-9B.

As illustrated in <FIG>, the wireless network <NUM> may include a number of base stations (BSs) <NUM> and other network entities. A BS may be a station that communicates with user equipments (UEs). Each BS <NUM> may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to a coverage area of a Node B (NB) and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and next generation NodeB (gNB), new radio base station (NR BS), <NUM> NB, access point (AP), or transmission reception point (TRP) may be interchangeable. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network <NUM> through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

<FIG> illustrates example components of BS <NUM> and UE <NUM> (as depicted in <FIG>), which may be used to implement aspects of the present disclosure. For example, antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE <NUM> and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS <NUM> may be used to perform the various techniques and methods described herein, such as described with respect to <FIG> and 9A-9B.

Modern user equipments (UEs) may include a plurality of antennas. One or more of the plurality of antennas may be used for transmitting (e.g., NTX = number of transmission antennas) data in a wireless network, such as described with respect to <FIG>, and likewise one or more of the plurality of antennas may be used for receiving (e.g., NRX = number of receiving antennas) data in the wireless network. In some cases, different sets of antennas are used for consecutive transmissions or receptions, which may generally be referred to as "antenna switching.

In a wireless communication network, such as an NR network, UEs may support sounding reference signal (SRS) transmissions with antenna switching. For example, in the case where NTX < NRX, SRS transmissions may be performed with antenna switching. In other words, a UE may transmit a first set of SRS resources using a first transmit antenna or set of antennas, and a second set of SRS resources using a second antenna, or set of antennas.

Different capabilities of UEs may be pre-defined, such as for use in standards defining capabilities of a wireless communication network like NR. For example, a UE may be configured to transmit on one of two antennas and to receive on both of the two antennas (referred to in shorthand as "1T2R"), or a UE may be configured to transmit on two of four antennas and to receive on all four of the antennas ("2T4R"), or a UE may be configured to transmit on one of four antennas and to receive on all four of the antennas ("1T4R"), and so on. Different combinations of transmit and receive capability for different numbers of antennas are possible. In some cases, the capabilities may be set for a UE by the network in downlink control information (DCI), for example using a "SRS-SetUse" resource indicator field.

A UE with multiple antennas can be configured with an SRS resource set that comprises one or more SRS resources for transmission from its multiple antennas. In some cases, a first resource of an SRS resource set may be configured for a first antenna configuration and a second resource of an SRS resource set may be configured for a second antenna configuration. Thus, SRS resource sets may support antenna switching in UEs.

UEs with multiple antennas may also be configured with multiple SRS resource sets. For example, a UE with two antennas may be configured with one SRS resource set (e.g., in a 1T2R configuration), whereas a UE with four antennas may be configured with more than one SRS resource set (e.g., in a 1T4R configuration).

SRS resources in a set are generally transmitted by a UE in the same slot, but separated by a guard period. During a guard period, the UE does not transmit any other signal, which allows for transition and settling time (e.g., between transmitting and receiving or between changing antenna configurations). For example, the guard period may include Y or at least Y intervening OFDM symbols that separate the SRS resource transmissions. By way of example, Y may be set to <NUM> for <NUM> subcarrier spacing (e.g., for above-<NUM> mmWave frequency ranges) and Y may be set to <NUM> for <NUM>, <NUM>, or <NUM> (e.g., in sub-<NUM> frequency ranges or in above-<NUM> mmWave frequency ranges where the subcarrier spacing is <NUM>). Other configurations are possible.

It may be desirable to place a guard period between any transmissions from a UE where there is an antenna switching event. Conventional guard periods may be scheduled between each individual SRS resource in an SRS resource sets (e.g., in UEs with multiple-antenna configurations), but these conventional guard periods may not account for antenna switching events before transmitting the first resource in the resource set and after transmitting the last resource in the resource set. Thus, additional or supplemental guard periods may be scheduled before the first SRS resource in a resource set, and after the last SRS resource in the resource set. For example, a guard period may be set before a first SRS resource in a resource set when there is an uplink transmission (e.g., PUSCH) from the same UE before the first SRS resource transmission and the first SRS resource transmission uses a different antenna configuration (i.e., an antenna switch) from the uplink transmission. As another example, a guard period may be set after the last SRS resource in a resource set when switching from an uplink (UL) transmission mode to a downlink (DL) reception mode. In some configurations, the additional guard periods may all be the same number of OFDM symbols (Y) in length.

There are several options for implementing the additional guard periods. One or more of these options may be implemented within an existing telecommunication standard or within a new telecommunication standard. A first option is by schedule restriction. In other words, a base station (BS) (such as described above with respect to <FIG> and <FIG>) may not schedule or configure a UE with any other UL transmissions, such as PUCCH and PUSCH transmissions, within Y symbols before the first SRS resource transmission in an SRS resource set or after the last SRS resource transmission in the SRS resource set.

A second option for providing the additional guard periods is by way of configuration of the SRS resource set itself. For example, the configuration of an SRS resource set for antenna switching may include zero-power ("dummy") SRS resources before and after the first and the last non-zero-power SRS resources in the set. The zero-power SRS resources emulate guard periods because the UE will not actually transmit any data (owing to the zero power) during that period.

While adding additional guard periods may be implemented in baseline or standard cases, there may be special or specific cases where additional guard periods can be avoided in order to reduce network overhead. In such cases, instead of additional guard periods, additional data symbols may be transmitted. In this way, the overall system may flexibly implement additional guard periods for antenna switching when necessary, but may forgo such additional guard periods when unnecessary in order to increase network utilization.

<FIG> depicts a portion of a network resource block <NUM> spanning two slots (N and N+<NUM>), which includes additional guard periods. Across the bottom of <FIG> is a symbol index, which indicates the symbol of the particular slot (in this case N or N+<NUM>). Note that while in this example each slot has <NUM> symbols (in index spots <NUM>-<NUM>), in other embodiments there may be different numbers of symbols in a slot.

In <FIG>, there is a conventional guard period at symbol index <NUM> between SRS resources SRS <NUM> and SRS <NUM>, which are part of an SRS resource set. This conventional guard period may provide time for a UE (such as those described with reference to the figures above) to switch from one antenna configuration to another antenna configuration. Additional guard periods are placed or scheduled at symbol indexes <NUM> and <NUM>. In particular, the guard period at symbol index <NUM> may be referred to as a forward or front guard period, which precedes the first SRS resource in an SRS resource set (here, SRS <NUM>). The front guard period may correspond to the case that the base station wants to give the UE a chance to try different antenna combinations between the PUSCH transmission and the SRS <NUM> transmission. Or, for example, in 2T4R configuration case, the PUSCH may be scheduled with one transmission antenna while the SRS <NUM> is configured with <NUM> transmission antennas. As discussed above, because in the latter case the numbers of antennas are different, there is an "antenna switching" event that requires a guard period.

The guard period at symbol index <NUM> in <FIG> may be referred to as a back or rear guard period, which follows the last SRS resource in the SRS resource set (here, SRS <NUM>).

For example, the front guard period at symbol index <NUM> may allow for time to switch an antenna configuration from the PUSCH transmission at symbol indexes <NUM> and <NUM> and the SRS resource (SRS <NUM>) transmission at symbol index <NUM>. As another example, the rear guard period at symbol index <NUM> may allow for time to switch to another antenna configuration from the SRS resource (SRS <NUM>) transmission at symbol index <NUM> and the downlink (DL) reception at symbol indexes <NUM> and <NUM> of Slot N+<NUM>.

<FIG> depicts a portion of a network resource block <NUM> spanning two slots (N and N+<NUM>), which includes an additional guard period. However, unlike the example in <FIG> depicts a special case where the front guard period is omitted. In particular, in this case the PUSCH is scheduled at symbol indexes <NUM>-<NUM> (one more than in <FIG>) because the front guard period (at symbol index <NUM> in <FIG>) is eliminated. In such a case, the UE may determine that because no guard period is scheduled between the PUSCH transmission (at symbol indexes <NUM>-<NUM>) and the first SRS resource (SRS <NUM>) transmission (at symbol index <NUM>), that the UE should use the same antenna configuration for both the PUSCH transmission and the SRS <NUM> transmission. So, for example, in the case of an UE configured for 1T2R and 1T4R, the same antenna should be used, or in the case of 2T4R, the same pair of antenna should be used. In some cases, the UE may infer this because, without the guard period, the UE would not have sufficient time to switch antenna configurations.

As depicted in <FIG>, the UE may infer an antenna configuration from the lack of the front guard period where the baseline or standard case would call for a front guard period (i.e., between the PUSCH and the SRS <NUM> transmissions, as in <FIG>). By contrast, in a case such as depicted in <FIG>, where there is a front guard period (at symbol index <NUM>), the UE could not infer that the same transmit antennas for the PUSCH transmission and the SRS <NUM> transmission could be used. Note that while in this example the PUSCH precedes the SRS <NUM> transmission, any other sort of transmission could precede the SRS <NUM> transmission, such as a PUCCH transmission.

Further, as explained above, there are two options for placing an effective guard period before a transmission. The example explained above follows the first option of scheduling the guard period. The second option, configuring the SRS resource set without a zero-power SRS resource preceding the SRS <NUM> transmission, is equally applicable. In other words, the existence or non-existence of the guard period may be implemented through many means.

<FIG> depicts a portion of a network resource block <NUM> spanning two slots (N and N+<NUM>), which includes an additional guard period. However, unlike the example in <FIG> depicts a special case where the rear guard period is omitted. Here again, the PUSCH is scheduled at symbol indexes <NUM>-<NUM> (one more than in <FIG>) because the rear guard period (at symbol index <NUM> in <FIG>) is eliminated.

The rear guard period may be omitted or removed under a variety of special cases. For example, if the UE has sufficient time between the uplink transmission and the downlink reception, for example because of a large propagation delay between the base station and the UE, the rear guard period may be removed. As another example, if the UE is not required to receive any downlink signal in the first downlink symbol (e.g., if the UE is not set for PDCCH monitoring or there is no PDSCH), then the rear guard period may be removed. As yet another example, the UE may indicate to the base station that no rear guard period is necessary through uplink signaling, such as RRC or MAC-CE.

As above there are at least two options for implementing the removal of the rear guard period. First, the UE may be informed by, for example, downlink control information (DCI) that the rear guard period should not be used; thus the removal of the rear guard period may be based on a scheduling instruction. Second, the SRS resource set may be configured without a rear zero-power SRS resource; thus the removal of the rear guard period may also be configuration-based.

<FIG> depicts a method <NUM> of selecting an antenna configuration for transmitting in a wireless communication network not claimed in the appended claims.

The method begins at step <NUM> with determining that a front guard period is not scheduled between a scheduled uplink transmission and a scheduled sounding reference signal (SRS) transmission. For example, as depicted in <FIG>, there is no front guard period before the first SRS resource (SRS <NUM>) at symbol index <NUM>.

The method then proceeds to step <NUM> where, based on the determination, the scheduled SRS transmission is transmitted using a first antenna configuration after (e.g., in the next OFDM symbol) transmitting the scheduled uplink transmission using the first antenna configuration (i.e., the same antenna configuration is used for the scheduled uplink transmission and the scheduled SRS transmission). For example, as depicted in <FIG>, the SRS <NUM> transmission at symbol index <NUM> is transmitted after the PUSCH uplink transmission ending at symbol index <NUM>.

Though not depicted in <FIG>, method <NUM> may further include changing the antenna configuration during a middle guard period following the transmission of the scheduled SRS transmission. For example, as depicted in <FIG>, the antenna configuration may be changed during the guard period at symbol index <NUM>.

Also not depicted in <FIG>, method <NUM> may also include receiving a network resource allocation from a network. In some examples, the network resource allocation comprises an SRS resource set, and in some examples a first SRS resource of the SRS resource set is separated from a second SRS resource of the SRS resource set by a middle guard period. For example, as depicted in <FIG>, the first SRS (SRS <NUM>) resource at symbol index <NUM> is separated from the second SRS resource (SRS <NUM>) at symbol index <NUM> by the guard period at symbol index <NUM>. In some examples, the second SRS resource of the SRS resource set is followed (e.g., in the next OFDM symbol) by a rear guard period. For example, as depicted in <FIG>, the second SRS resource (SRS <NUM>) at symbol index <NUM> is followed by the rear guard period at symbol index <NUM>. In some examples of method <NUM>, the rear guard period comprises a zero-power SRS resource, as discussed above.

In some examples, method <NUM> is performed by a UE within an NR wireless communication network.

<FIG> depicts a method <NUM> of selecting an antenna configuration for transmitting in a wireless communication network according to the present invention. The method <NUM> begins at step <NUM> with determining that a rear guard period is not needed between a scheduled sounding reference signal (SRS) transmission and a scheduled downlink transmission.

Method <NUM> then proceeds to step <NUM> where the scheduled SRS transmission is transmitted using a first antenna configuration. For example, as depicted in <FIG>, the SRS resource (SRS <NUM>) at symbol index <NUM> may be transmitted using a first antenna configuration for transmission.

Method <NUM> then proceeds to step <NUM>, where the first antenna configuration is changed to a second antenna configuration. For example, a different antenna may be selected where a device, such as a user equipment, has multiple antennas that can be used for transmission and reception.

Method <NUM> then proceeds to step <NUM> where the scheduled downlink transmission is received using the second antenna configuration without observing an intervening guard period. For example, as depicted in <FIG>, downlink data at symbols <NUM> and <NUM> of slot N+<NUM> may be received after (e.g., in the next OFDM symbol) transmitting SRS resource (SRS <NUM>) at symbol index <NUM> in slot N. Notably, while the SRS <NUM> transmission and downlink (DL) reception are in adjacent symbol periods in <FIG>, there may nevertheless be a time interval (e.g., gap) between the transmission and the reception from the perspective of the UE because of the roundtrip time between the UE and the base station (which is twice the propagation delay).

In some examples of method <NUM>, determining that the rear guard period is not needed includes determining a propagation delay between a base station and a user equipment (UE) is sufficient to allow for changing between the first antenna configuration and the second antenna configuration without the rear guard period.

In other examples of method <NUM>, determining that the rear guard period is not needed comprises receiving downlink control information (DCI) from a base station indicating that the rear guard period is not needed.

In yet other examples of method <NUM>, determining that the rear guard period is not needed comprises determining that it is not necessary to receive the first symbol of the scheduled downlink transmission.

Though not depicted in <FIG>, method <NUM> may also include receiving a network resource allocation from a network. In some examples, the network resource allocation comprises an SRS resource set, wherein a first SRS resource of the SRS resource set is separated from a second SRS resource of the SRS resource set by a middle guard period. For example, as depicted in <FIG>, a first SRS resource (SRS <NUM>) at symbol index <NUM> is separated from a second SRS resource (SRS <NUM>) at symbol index <NUM> by a middle guard period at symbol index <NUM>. Further, in some examples, the first SRS resource of the SRS resource set is preceded by a front guard period. For example, as depicted in <FIG>, the first SRS resource (SRS <NUM>) at symbol index <NUM> is preceded by a front guard period at symbol index <NUM>. In some examples, the front guard period comprises a zero-power SRS resource.

<FIG> depicts a method <NUM> of scheduling networking resources in a wireless communication network. The method <NUM> begins at step <NUM> with transmitting a network resource allocation to a user equipment (UE). For example, the network allocation may comprise resource blocks or other forms of scheduling data, such as depicted in <FIG>.

In some examples of method <NUM>, the network resource allocation comprises an SRS resource set. In some examples, the SRS resource set may include multiple SRS reference signals configured for different antenna configurations of a UE. For example, <FIG> depict resource sets including SRS <NUM> and SRS <NUM>, which may be individually configured for different antenna configurations.

In some examples of method <NUM>, a first SRS resource of the SRS resource set is separated from a second SRS resource of the SRS resource set by a middle guard period (such as described above with respect to <FIG>).

In some examples of method <NUM>, the second SRS resource of the SRS resource set is followed by a rear guard period (such as described above with respect to <FIG>). In some examples, the rear guard period comprises a zero-power SRS resource.

Though not depicted in <FIG>, method <NUM> may further include receiving the scheduled SRS transmission from the UE after receiving the scheduled uplink from the UE. For example, as depicted in <FIG>, the SRS <NUM> transmission at symbol index <NUM> may be received after receiving the PUSCH uplink transmission ending at symbol index <NUM>.

In some examples, method <NUM> is performed by a base station in an NR wireless communication network.

<FIG> depicts another method <NUM> of scheduling network resources in a wireless communication network.

Method <NUM> begins at step <NUM> with determining that a rear guard period is not needed between a scheduled sounding reference signal (SRS) transmission and a scheduled downlink transmission.

Method <NUM> then proceeds to step <NUM> where the scheduled SRS transmission is received, for example, from a user equipment (UE).

Method <NUM> then proceeds to step <NUM> where the scheduled downlink transmission is transmitted, for example, from a base station, after receiving the scheduled SRS transmission without observing an intervening guard period. For example, as depicted in <FIG>, the downlink transmission at symbols <NUM> and <NUM> of Slot N+<NUM> are transmitted after receiving the SRS resource (SRS <NUM>) at symbol index <NUM> of Slot N.

In some examples of method <NUM>, determining that the rear guard period is not needed comprises determining a propagation delay between a base station and a UE is sufficient to allow the UE to change between a first antenna configuration for transmitting and a second antenna configuration for receiving without the rear guard period.

Though not depicted in <FIG>, method <NUM> may also include transmitting downlink control information (DCI) from the base station to the UE indicating that the rear guard period is not needed.

In some examples of method <NUM>, determining that the rear guard period is not needed comprises determining that it is not necessary to transmit the first symbol of the scheduled downlink transmission to the UE. For example, with respect to <FIG>, it may be determined that the first symbol of the downlink transmission at symbol index <NUM> of Slot N+<NUM> need not be transmitted.

Though not depicted in <FIG>, method <NUM> may also include transmitting a network resource allocation to the UE. In some examples, the network resource allocation comprises an SRS resource set, wherein a first SRS resource of the SRS resource set is separated from a second SRS resource of the SRS resource set by a middle guard period, and wherein the first SRS resource of the SRS resource set is preceded by a front guard period. For example, as depicted in <FIG>, the resource set including SRS <NUM> and SRS <NUM> is separated by a middle guard period at symbol index <NUM>, and SRS <NUM> at symbol index <NUM> is preceded by the front guard period at symbol index <NUM>. In some examples, the front guard period comprises a zero-power SRS resource.

<FIG> illustrates a communications device <NUM> that 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 in <FIG> and 9A-9B. The transceiver <NUM> is configured to transmit and receive signals for the communications device <NUM> via an antenna <NUM>, such as the various signal described herein.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions that when executed by processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG> and 9A-9B, or other operations for performing the various techniques discussed herein.

In certain aspects, the processing system <NUM> further includes a determining component <NUM> for performing the operations illustrated in <FIG> and 9A-9B. Additionally, the processing system <NUM> includes a transmitting component <NUM> for performing the operations illustrated in <FIG> and 9A-9B. Additionally, the processing system <NUM> includes a receiving component <NUM> for performing the operations illustrated in <FIG> and 9A-9B. The determining component <NUM>, transmitting component <NUM>, and receiving component <NUM> may be coupled to the processor <NUM> via bus <NUM>. In certain aspects, the determining component <NUM>, transmitting component <NUM>, and receiving component <NUM> may be hardware circuits. In certain aspects, the determining component <NUM>, transmitting component <NUM>, and receiving component <NUM> may be software components that are executed and run on processor <NUM>.

For example, instructions for performing the operations described herein and illustrated in <FIG> and 9A-9B.

Claim 1:
A method of selecting an antenna configuration for communicating in a wireless communication network by a user equipment, UE (<NUM>), comprising:
determining (<NUM>) that a rear guard period for changing from a first antenna configuration to a second antenna configuration is not needed between a scheduled sounding reference signal, SRS, transmission and a scheduled downlink transmission;
transmitting (<NUM>) the scheduled SRS transmission using the first antenna configuration;
changing (<NUM>) from the first antenna configuration to the second antenna configuration; and
receiving (<NUM>) the scheduled downlink transmission using the second antenna configuration without observing the rear guard period,
wherein determining that the rear guard period is not needed comprises:
determining a propagation delay between a base station (<NUM>) and a user equipment (<NUM>) is sufficient to allow for changing between the first antenna configuration and the second antenna configuration without the rear guard period; or
determining that it is not necessary to receive a first symbol of the scheduled downlink transmission.