WO2025065599A1

WO2025065599A1 - Sounding reference signal collision handling and associated data transmission

Info

Publication number: WO2025065599A1
Application number: PCT/CN2023/122834
Authority: WO
Inventors: Guangyu JIANG; Bo Gao; Ke YAO
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2023-09-28
Filing date: 2023-09-28
Publication date: 2025-04-03
Anticipated expiration: 2026-03-28

Abstract

Methods, apparatus, and systems that relate to handling of Sounding Reference Signal (SRS) dropping and handling of data transmission (s) after SRS dropping are disclosed. In one example aspect, a method for wireless communication includes dropping, by a wireless communication device in response to a collision between an SRS to a network device and a signal to the network device, at least part of the SRS according to a rule. The rule is at least associated with a time duration within which two or more SRSs are expected to be coherent. The method includes receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped; and performing, by the wireless communication device, a data transmission to the network device based on the control information.

Description

SOUNDING REFERENCE SIGNAL COLLISION HANDLING AND ASSOCIATED DATA TRANSMISSION

TECHNICAL FIELD

This patent document is directed to digital communications.

BACKGROUND

Mobile communication technologies are moving the world toward an increasingly connected and networked society. The rapid growth of mobile communications and advances in technology have led to greater demand for capacity and connectivity. Other aspects, such as energy consumption, device cost, spectral efficiency, and latency are also important to meeting the needs of various communication scenarios. Various techniques, including new ways to provide higher quality of service, longer battery life, and improved performance are being discussed.

SUMMARY

This patent document describes, among other things, techniques related to the handling of Sounding Reference Signal (SRS) dropping and the handling of data transmission (s) after SRS dropping.

In one example aspect, a method for wireless communication includes dropping, by a wireless communication device in response to a collision between a Sounding Reference Signal (SRS) to a network device and a signal to the network device, at least part of the SRS according to a rule. The rule is at least associated with a time duration within which two or more SRSs that are expected to be coherent. The method includes receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped; and performing, by the wireless communication device, a data transmission to the network device based on the control information.

In another example aspect, a method for wireless communication includes transmitting, by a network device, control information to a wireless communication device corresponding to at least part of an SRS being dropped in response to a collision between the SRS from the wireless communication device and a signal from the wireless communication device. The dropping of the SRS is based on a rule that is at least associated with a time duration within which two or more SRSs that are expected to be coherent. The method includes receiving, by the network device, a data transmission from the wireless communication device based on the control information.

In another example aspect, a method for wireless communication includes dropping, by a wireless communication device in response to a collision between a Sounding Reference Signal (SRS) to a network device and a signal to the network device, at least part of the SRS. The method includes receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped; and performing, by the wireless communication device in response to the dropping of the at least part of the SRS, a data transmission to the network device based on at least a time duration within which an SRS and a data transmission to the network device are expected to be coherent.

In another example aspect, a method for wireless communication includes transmitting, by a network device, control information to a wireless communication device corresponding to at least part of a Sounding Reference Signal (SRS) being dropped in response to a collision between the SRS from the wireless communication device and a signal from the wireless communication device. The method also includes a data transmission from the wireless communication device based on at least a time duration within which an SRS and a data transmission from the wireless communication device are expected to be coherent.

In another example aspect, a method for wireless communication includes determining, by a wireless communication device or a network device, a time duration within which two or more SRSs to the network device that are expected to be coherent.

In another example aspect, a method for wireless communication includes determining, by a wireless communication device or a network device, a time duration within which an SRS to the network device and a data transmission to the network device are expected to be coherent.

In another example aspect, a communication apparatus is disclosed. The apparatus includes a processor that is configured to implement an above-described method.

In yet another example aspect, a computer-program storage medium is disclosed. The computer-program storage medium includes code stored thereon. The code, when executed by a processor, causes the processor to implement a described method.

These, and other, aspects are described in the present document.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example Time Division Multiplexing (TDM) scheme for SRS transmissions.

FIG. 2A is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology.

FIG. 2B is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology.

FIG. 3 illustrates an example partial dropping based on a rule in accordance with one or more embodiments of the present technology.

FIG. 4 illustrates an example full dropping based on a rule in accordance with one or more embodiments of the present technology.

FIG. 5 illustrates an example timeline restriction in accordance with one or more embodiments of the present technology.

FIG. 6A is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology.

FIG. 6B is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology.

FIG. 7 illustrates an example data transmission after a full SRS dropping in accordance with one or more embodiments of the present technology.

FIG. 8 illustrates an example data transmission after a partial SRS dropping in accordance with one or more embodiments of the present technology.

FIG. 9A is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology.

FIG. 9B is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology.

FIG. 10 illustrates an example SRS coherent time in accordance with one or more embodiments of the present technology.

FIG. 11 illustrates an example SRS-Physical Uplink Shared Channel (PUSCH) coherent time in accordance with one or more embodiments of the present technology.

FIG. 12 shows an example of a wireless communication system where techniques in accordance with one or more embodiments of the present technology can be applied.

FIG. 13 is a block diagram representation of a portion of a radio station in accordance with one or more embodiments of the present technology can be applied.

DETAILED DESCRIPTION

Section headings are used in the present document only to improve readability and do not limit scope of the disclosed embodiments and techniques in each section to only that section. Furthermore, some embodiments are described with reference to Third Generation Partnership Project (3GPP) Fifth Generation (5G) New Radio (NR) or Sixth Generation (6G) standard for ease of understanding and the described technology may be implemented in different wireless system that implement protocols other than the NR or 6G protocol.

In wireless communication systems, a wireless communication device (also referred to as User Equipment (UE) , a user device, a terminal, etc. ) transmits one or more Sounding Reference Signals (SRSs) to a network device (also referred to as a base station (BS) , a network node, etc. ) so that the network device can determine the channel quality of the uplink path (s) from the UE to the network and adjust parameters for data transmissions to achieve better transmission quality. The general procedure of codebook-based data transmission on the Physical Uplink Shared Channel (PUSCH) is as follows:

Step 1: The UE transmits a Sounding Reference Signal (SRS) to the BS.

Step 2: The BS transmits a signaling message, such as a Downlink Control Information (DCI) signaling, to indicate data transmission parameter (s) . For example, the DCI signaling can include the Transmitted Precoder Indicator (TPMI) and/or SRS Resource Indicator (SRI) to indicate parameters associated with the PUSCH transmission.

Step 3: The UE performs the data transmission (e.g., PUSCH transmission) based on the parameter (s) in the signaling message.

The SRS can fully or partially overlap with other signals with a higher priority (e.g., transmissions on the Physical Uplink Control Channel, PUCCH) . In those cases, the SRS is dropped to enable the transmission of higher-priority signals. Before Release 18 of the Third-Generation Partnership Project (3GPP) Technical Specifications, SRS transmission is implemented using a time-domain granularity of symbols. In other words, the SRS is carried in an Orthogonal Frequency-Division Multiplexing (OFDM) symbol. If the SRS collides with higher-priority uplink signal (s) , UE drops the SRS on the collided symbol. In Release 18, Time Division Multiplexing (TDM) scheme is supported for 8-port SRS. FIG. 1 illustrates an example TDM scheme for SRS. As shown in FIG. 1, given the TDM scheme, the configured SRS ports distribute over multiple symbols (e.g., two symbols in this example) . In this case, the collision of the SRS with the higher-priority uplink signal (s) may occur over only part of the symbols. The UE then has two options for SRS dropping:

Option 1: Partial dropping. Using this option, the UE only drops the collided symbol that is mapped to the SRS.

Option 2: Full dropping. Using this option, the UE drops all symbols mapped to the SRS.

Currently, it is unclear under what circumstances UE should adopt full or partial SRS dropping. Furthermore, when the UE drops the SRS either partially or fully, the BS cannot obtain a full or valid channel estimate to determine the channel conditions. Correspondingly, the UE cannot receive meaning configuration information for the uplink data transmission. How the UE should perform the transmission without proper configuration information from the BS remains to be a problem.

This patent document discloses techniques that can be implemented in various embodiments to enable the UE to determine whether partial dropping or full dropping of the SRS symbols should be adopted. The disclosed techniques can also be implemented to enable the UE to determine transmission behavior when SRS dropping occurs.

Details regarding the above techniques are further discussed in the embodiments below.

Embodiment 1

This embodiment is related rules for determining whether full dropping or partial dropping of the SRS should be performed.

FIG. 2A is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. The method 200 includes, at operation 210, dropping, by a wireless communication device in response to a collision between a Sounding Reference Signal (SRS) to a network device and a signal to the network device, at least part of the SRS according to a rule. The rule is at least associated with a time duration within which two or more SRSs that are expected to be coherent. The method 200 includes, at operation 220, receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped. The method 200 includes, at operation 230, performing, by the wireless communication device, a data transmission to the network device based on the control information.

FIG. 2B is a flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. The method 250 includes, at operation 260, transmitting, by a network device, control information to a wireless communication device corresponding to at least part of an SRS being dropped in response to a collision between the SRS from the wireless communication device and a signal from the wireless communication device. The dropping of the SRS is based on a rule that is at least associated with a time duration within which two or more SRSs that are expected to be coherent. The method 250 includes, at operation 270, receiving, by the network device, a data transmission from the wireless communication device based on the control information.

For an SRS (e.g., an SRS resource configured with usage “codebook” and TDM scheme) , if the SRS collides with a higher-priority uplink signal (s) over part of the symbols, UE decides whether partial or full dropping of the symbols mapped to the SRS based on a rule that is associated with an SRS coherent time T_coh, SRS. In some embodiments, the SRS coherent time T_coh, SRS can be defined as the maximum allowed time-domain distance between two SRSs that are expected to be coherent. For example, T_coh, SRS can be represented using J time units, where J is a positive integer, and a time unit comprises a frame, a subframe, a slot, a symbol, or a millisecond.

In some embodiments, the SRS coherent time T_coh, SRS can be configured via Radio Resource Configuration (RRC) signaling, reported by UE, or be a predefined value. The SRS coherent time T_coh, SRS can be 1 symbol or N_s symbol, where N_s is the number of symbols of the SRS resource. The SRS coherent time T_coh, SRS can be determined by at least one of: the subcarrier spacing for the uplink channel, a reported UE capability. The SRS coherent time T_coh, _SRS can be determined according to T_coh, SRS = M·X·2^μ, where M is a predefined value, X is a value denoting UE capability, and μ is a value associated with subcarrier spacing for the uplink channel.

In some embodiments, the rule specifies that, if the UE determines that the portion of the SRS symbols that is not in collision can be combined with another SRS located within T_coh, _SRS before or after the portion to construct an SRS transmission with complete port information, the UE performs partial dropping to drop the collided SRS symbols. Otherwise, UE performs a full dropping to drop all the symbols mapped to the SRS. In some embodiments, the two SRSs that can be combined to construct an SRS transmission with complete port information can be two parts of a SRS resource, and the two SRSs are mapped onto two groups of adjacent symbols, where every group of adjacent symbols are TDMed.

In some embodiment, the rule specifies that, in case a SRS resource with nrofSRS-Ports set as ‘n8’ and [tdm] is scheduled on N_s adjacent OFDM symbols in a slot, and the SRS resource is associated with a PUSCH transmission with codebookType set to ‘codebook1, ’ antenna ports {1000, 1001, 1004, 1005} of the SRS resource are mapped onto half of the Ns adjacent OFDM symbols, antenna ports {1002, 1003, 1006, 1007} of the SRS resource are mapped onto the other half of the Ns OFDM symbols according to clause 6.4.1.4.2 of [4, TS 38.211] , for each two adjacent OFDM symbols of the Ns OFDM symbols which are TDMed, if only one of the two adjacent OFDM symbols is configured with higher-priority up-link signal, UE shall drop the SRS symbol overlapping with the higher-priority uplink signal, and if the other SRS symbol from the two adjacent OFDM symbols carries antenna ports {1000, 1001, 1004, 1005} of the SRS resource, and antenna ports {1002, 1003, 1006, 1007} cannot be transmitted on another SRS symbol of the SRS resource no earlier than [J] symbols before, or no later than [J] symbols after the other SRS symbol, UE shall drop the other SRS symbol, if the other SRS symbol from the two adjacent OFDM symbols carries antenna ports {1002, 1003, 1006, 1007} of the SRS resource, and antenna ports {1000, 1001, 1004, 1005} cannot be transmitted on another SRS symbol of the SRS resource no earlier than [J] symbols before, or no later than [J] symbols after the other SRS symbol, UE shall drop the other SRS symbol, Otherwise, UE shall transmit the other SRS symbol from the two adjacent OFDM symbols. The higher-priority uplink signal refers to aperiodic SRS for semi-persistent/periodic SRS, and refers to aperiodic/semi-persistent SRS for periodic SRS.

FIG. 3 illustrates an example partial dropping based on a rule in accordance with one or more embodiments of the present technology. In this example, an 8-port SRS is mapped onto two TDM symbols. The UE is scheduled to transmit SRS 310, 320 before the subsequent data transmission on PUSCH. For SRS 310, symbol 313 collides with a higher-priority uplink signal. The UE then determines whether partial dropping or full dropping of the SRS 310 should be performed based on a rule that is associated with the SRS coherent time T_coh, SRS.

The SRS coherent time T_coh, SRS can be determined based on a predefined value, a reported UE capability information, or configuration information (e.g., subcarrier spacing for the uplink channel) . In this case, the UE finds that symbol 311, which does not collide with the higher-priority uplink signal, can be combined with SRS 320 that is located within T_coh, SRS after symbol 311 to construct a full 8-port SRS transmission. In this case, the UE performs partial dropping and only drops symbol 313.

FIG. 4 illustrates an example full dropping based on a rule in accordance with one or more embodiments of the present technology. In this example, an 8-port SRS is mapped onto two TDM symbols. The UE is scheduled to transmit one SRS 410 before the subsequent data transmission on PUSCH. For SRS 410, symbol 413 collides with a higher-priority uplink signal. The UE then determines whether partial dropping or full dropping of the SRS 410 should be performed based on a rule that is associated with the SRS coherent time T_coh, SRS.

The SRS coherent time T_coh, SRS can be determined based on a predefined value, a reported UE capability information, or configuration information (e.g., subcarrier spacing for the uplink channel) . In this case, the UE finds that symbol 411 cannot be combined with any SRS located within T_coh, SRS before or after symbol 411 to construct a full 8-port SRS transmission, as there is no other SRS within T_coh, SRS before or after symbol 411. In this case, the UE performs full dropping and drops both symbols 411 and 413.

In some embodiments, whether UE adopts the above dropping rule is additionally based on whether it is informed of the collision in time within a timeline restriction. FIG. 5 illustrates an example timeline restriction in accordance with one or more embodiments of the present technology. As shown in FIG. 5, in some embodiments, the UE expects to be informed of the collision information no later than K time units before the collision occurs, and a time unit comprises a frame, a subframe, a slot, a symbol, or a millisecond. For example, if the UE is informed of the collision information no later than K time units before the collision occurs, the UE adopts the above SRS dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, if the higher-priority uplink signal is triggered by a DCI signaling, the UE expects to receive the DCI signaling no later than K time units before the collision occurs. If the UE receives the DCI signaling no later than K time units before the collision occurs, the UE adopts the above SRS dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, if the SRS is aperiodic, the UE expects to receive a DCI signaling that triggers the SRS no later than K time units before the collision occurs. If the UE receives the DCI signaling triggering the SRS no later than K time units before the collision happens, the UE adopts the above SRS dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, if the SRS is semi-persistent, UE expects to receive a Medium Access Control (MAC) Control Element (CE) activating the SRS no later than K time units before the collision occurs. If the UE receives the MAC CE activating the SRS no later than K time units before the collision happens, the UE adopts the above SRS dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In the embodiments above, the value of K is a positive integer, and can be configured via RRC signaling, reported by UE, or a predefined value. K can also be determined by at least one of: a predefined value, a UE capability, or the subcarrier spacing for uplink channel.

In some embodiments, whether the UE adopts the SRS dropping rule is additionally determined by a higher layer parameter codebookSubset that is carried in RRC PUSCH configuration information, indicating subset of Precoding Matrix Indicators (PMIs) addressed by the Transmit Precoder Matrix Indicator (TPMI) . The value of the parameter codebookSubset can be “fullyAndPartialAndNonCoherent” , “partialAndNonCoherent” , or “nonCoherent. ” Details regarding parameter codebookSubset can be found in 3GPP TS 38.331.

In some embodiments, if the higher layer parameter codebookSubset is set to “fullyAndPartialAndNonCoherent” , UE adopts the above dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, if the higher layer parameter codebookSubset is set to “partialAndNonCoherent” or “fullyAndPartialAndNonCoherent” , UE adopts the above dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, whether the UE adopts the above dropping rule is additionally determined by the coherent antenna group number Ng. For example, referring back to the example shown in FIG. 5, for an 8-port SRS, the ports are not expected to have coherency when Ng=8 (having eight antenna groups) . On the other hand, if Ng < 8, at least some of the ports are considered to be coherent. Correspondingly, when Ng < 8, the UE adopts the above dropping rule. Otherwise, the UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, whether the UE adopts the above dropping rule is additionally determined by the higher layer parameter codebookType. The value of the parameter codebookType can be “codebook1, ” “codebook2, ” “codebook3, ” or “codebook4. ” Details regarding parameter codebookType can be found in 3GPP TS 38.2111.

In some embodiments, if the higher layer parameter codebookType is set to “codebook1, ” UE adopts the above dropping rule. Otherwise, UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

In some embodiments, if the higher layer parameter codebookType is set to “codebook1, ” “codebook2, ” or “codebook3, ” UE adopts the above dropping rule. Otherwise, UE uses a default approach (either option 1 for partial dropping or option 2 for full dropping) for SRS dropping.

Embodiment 2

This embodiment is related rules for performing uplink data transmission when SRS dropping occurs.

FIG. 6A is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. The method 600 includes, at operation 610, dropping, by a wireless communication device in response to a collision between a Sounding Reference Signal (SRS) to a network device and a signal to the network device, at least part of the SRS. The method 600 includes, at operation 620, receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped. The method 600 includes, at operation 630, performing, by the wireless communication device in response to the dropping of the at least part of the SRS, a data transmission to the network device based on at least a time duration within which an SRS and a data transmission to the network device are expected to be coherent.

FIG. 6B is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. The method 650 includes, at operation 660, transmitting, by a network device, control information to a wireless communication device corresponding to at least part of a Sounding Reference Signal (SRS) being dropped in response to a collision between the SRS from the wireless communication device and a signal from the wireless communication device. The method 650 includes, at operation 670, receiving, by the network device, a data transmission from the wireless communication device based on at least a time duration within which an SRS and a data transmission from the wireless communication device are expected to be coherent.

In some embodiments, when SRS dropping occurs, if no SRS is transmitted within an SRS-PUSCH coherent time T_{coh, SRS-PUSCH} before the first symbol of a data transmission (e.g., a PUSCH transmission) , the UE can ignore the control information from the BS (e.g., TPMI indicated by the DCI) and use a default transmit precoding matrix to perform the data transmission. In some embodiments, the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be defined as the maximum allowed time-domain distance between an SRS and a PUSCH transmission that are expected to be coherent. For example, T_{coh, SRS-PUSCH} can be represented using L time units, where L is a positive integer, and a time unit comprises a frame, a subframe, a slot, a symbol, or a millisecond.

In some embodiments, the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be configured via Radio Resource Configuration (RRC) signaling, reported by UE, or a predefined value. In some embodiments, the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be one of {10, 11, ..., 100} symbols. In some embodiments, the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be determined by at least one of: the subcarrier spacing for the uplink channel, a reported UE capability. In some embodiments, the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be determined according to T_{coh, SRS-PUSCH} = N·Y·2^μ, where N is a predefined value, Y is a value denoting UE capability, and μ is a value associated with subcarrier spacing for the uplink channel.

FIG. 7 illustrates an example data transmission after a full SRS dropping in accordance with one or more embodiments of the present technology. In this example, an 8-port SRS configured with TDM scheme is mapped onto two OFDM symbols. Both the OFDM symbols collide with a higher-priority uplink signal, and all symbols mapped to the SRS are dropped. As shown in FIG. 7, because no SRS is transmitted within T_{coh, SRS-PUSCH} before the first symbol of a PUSCH transmission, the UE can ignore the TPMI indicated by the DCI and use a default precoding matrix to perform the PUSCH transmission.

In some embodiments, the default precoding matrix can be one of candidate precoding matrices corresponding to: codebookType = “codebook4, ” Ng = 8, or, codebookSubset = “noncoherent. ” In some embodiments, the number of layers corresponding to the default precoding matrix can be limited as 1.

In some embodiments, when SRS dropping occurs, if no SRS is transmitted within an SRS-PUSCH coherent time T_{coh, SRS-PUSCH} before the first symbol of a data transmission (e.g., a PUSCH transmission) , the UE can expect that the control information from the BS includes certain information. In some embodiments, SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be defined as the maximum allowed time-domain distance between an SRS and a PUSCH transmission that are expected to be coherent.

In some embodiments, the UE can expect that the precoding matrix indicated by the TPMI is one of candidate precoding matrices corresponding to at least one of: codebookType = “codebook4, ” Ng = 8, or codebookSubset = “noncoherent. ” In some embodiments, the UE can interpret the bit field “Precoding information and number of layers” in the DCI as at least one of codebookType = “codebook4, ” Ng = 8, or codebookSubset = “nonCoherent” even when the DCI indicates otherwise (e.g., codebookType ≠ “codebook4” and Ng ≠ 8, or codebookSubset ≠ “noncoherent” ) . In some embodiments, the UE can expect that the number of layers corresponding to the precoding matrix indicated by the TPMI is no larger than a threshold (e.g., Rthreshold) . In some embodiments, the threshold Rthreshold can be equal to 1.

In some embodiments, when SRS dropping occurs, if only part of the SRS is transmitted within the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} before the first symbol of a data transmission (e.g., a PUSCH transmission) , the UE can ignore the control information from the BS (e.g., TPMI indicated by the DCI) and use a default precoding matrix to perform the data transmission. In some embodiments, SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be defined as the maximum allowed time-domain distance between an SRS and a PUSCH transmission that are expected to be coherent. FIG. 8 illustrates an example data transmission after a partial SRS dropping in accordance with one or more embodiments of the present technology. In this example, an 8-port SRS configured with TDM scheme is mapped onto two OFDM symbols. The second OFDM symbol collides with a higher-priority uplink signal and is dropped. As shown in FIG. 8, because only part of the SRS ports (e.g., {1000, 1001, 1004, 1005} ) is transmitted within T_{coh, SRS-PUSCH} before the first symbol of a PUSCH transmission, the UE can ignore the TPMI indicated by the DCI and use a default precoding matrix to perform the PUSCH transmission.

In some embodiments, the default precoding matrix can be one of the precoding matrices for codebookType = “codebook4” , Ng = 8. or codebookSubset = “nonCoherent” . In some embodiments, the number of layers corresponding to the default precoding matrix can be limited as 1.

In some embodiments, when SRS dropping occurs, if only part of the SRS is transmitted within the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} before the first symbol of a data transmission (e.g., a PUSCH transmission) , the UE can expect that the control information from the BS includes certain information. In some embodiments, SRS-PUSCH coherent time T_coh, SRS- _PUSCH can be defined as the maximum allowed time-domain distance between an SRS and a PUSCH transmission that are expected to be coherent.

In some embodiments, the UE can expect that the precoding matrix indicated by the TPMI is for at least one of: codebookType = “codebook4” , Ng = 8, or codebookSubset = “nonCoherent” . In some embodiments, the UE expects that the entries corresponding to the collided/dropped SRS ports in the precoding matrix are set to 0 in the control information (e.g., the DCI signaling) .

In some embodiments, UE can interpret the bit field “Precoding information and number of layers” in the DCI as codebookType = “codebook4” and Ng = 8, or codebookSubset =“noncoherent” even when the DCI indicates otherwise (e.g., codebookType ≠ “codebook4” and Ng ≠ 8, or codebookSubset ≠ “noncoherent” ) . In some embodiments, the UE can expect that the number of layers corresponding to the precoding matrix indicated by the TPMI is no larger than a threshold (e.g., Rthreshold) . In some embodiments, the threshold Rthreshold can be equal to 1. In some embodiments, the UE can expect that the number of layers corresponding to the precoding matrix indicated by the TPMI is no larger than a threshold (e.g., Rthreshold) . In some embodiments, the threshold Rthreshold can be equal to 1.

In some embodiments, if codebookType = “codebook2” and Ng = 2, or codebookSubset = “partialAndNonCoherent” , the UE can expect that the entries corresponding to the collided/dropped SRS ports in the precoding matrix indicated by the TPMI are 0. In some embodiments, if codebookType = “codebook3” and Ng = 4, or codebookSubset = “partialAndNonCoherent” , the UE can expect that the entries corresponding to the collided/dropped SRS ports in the precoding matrix indicated by the TPMI are 0.

Embodiment 3

This embodiment is related to the determination of the SRS coherent time and the SRS-PUSCH coherent time.

FIG. 9A is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. The method 900 includes, at operation 910, determining, by a wireless communication device or a network device, a time duration within which two or more SRSs to the network device that are expected to be coherent.

FIG. 9B is flowchart representation of a method for wireless communication in accordance with one or more embodiments of the present technology. The method 950 includes, at operation 960, determining, by a wireless communication device or a network device, a time duration within which an SRS to the network device and a data transmission to the network device are expected to be coherent.

FIG. 10 illustrates an example SRS coherent time in accordance with one or more embodiments of the present technology. As shown in FIG. 10, the SRS coherent time T_coh, SRS can be defined as maximum allowed time-domain distance between two SRSs that are expected to be coherent. The UE expects that the time distance between a first SRS and a second, coherent SRS is smaller than or equal to T_coh, SRS, wherein the first and the second SRSs are used to determine at least one of: DCI, or SRS Resource Indicator (SRI) for a PUSCH.

FIG. 11 illustrates an example SRS-PUSCH coherent time in accordance with one or more embodiments of the present technology. As shown in FIG. 11, the SRS-PUSCH coherent time T_{coh, SRS-PUSCH} can be defined as the maximum allowed time-domain distance between an SRS and a PUSCH transmission that are expected to be coherent. The UE expects that the time distance between an SRS and the first symbol of the PUSCH that is coherent with the SRS is smaller than or equal to T_{coh, SRS-PUSCH} , where the SRS is used to determine at least one of: DCI, TPMI, or SRI for a PUSCH.

FIG. 12 shows an example of a wireless communication system 1200 where techniques in accordance with one or more embodiments of the present technology can be applied. A wireless communication system 1200 can include one or more base stations (BSs) 1205a, 1205b, one or more wireless devices (or UEs) 1210a, 1210b, 1210c, 1210d, and a core network 1225. A base station 1205a, 1205b can provide wireless service to user devices 1210a, 1210b, 1210c and 1210d in one or more wireless sectors. In some implementations, a base station 1205a, 1205b includes directional antennas to produce two or more directional beams to provide wireless coverage in different sectors. The core network 1225 can communicate with one or more base stations 1205a, 1205b. The core network 1225 provides connectivity with other wireless communication systems and wired communication systems. The core network may include one or more service subscription databases to store information related to the subscribed user devices 1210a, 1210b, 1210c, and 1210d. A first base station 1205a can provide wireless service based on a first radio access technology, whereas a second base station 1205b can provide wireless service based on a second radio access technology. The base stations 1205a and 1205b may be co-located or may be separately installed in the field according to the deployment scenario. The user devices 1210a, 1210b, 1210c, and 1210d can support multiple different radio access technologies. The techniques and embodiments described in the present document may be implemented by the base stations of wireless devices described in the present document.

FIG. 13 is a block diagram representation of a portion of a radio station in accordance with one or more embodiments of the present technology can be applied. A radio station 1305 such as a network node, a base station, or a wireless device (or a user device, UE) can include processor electronics 1310 such as a microprocessor that implements one or more of the wireless techniques presented in this document. The radio station 1305 can include transceiver electronics 1315 to send and/or receive wireless signals over one or more communication interfaces such as antenna 1320. The radio station 1305 can include other communication interfaces for transmitting and receiving data. Radio station 1305 can include one or more memories (not explicitly shown) configured to store information such as data and/or instructions. In some implementations, the processor electronics 1310 can include at least a portion of the transceiver electronics 1315. In some embodiments, at least some of the disclosed techniques, modules or functions are implemented using the radio station 1305. In some embodiments, the radio station 1305 may be configured to perform the methods described herein.

The disclosed and other embodiments, modules and the functional operations described in this document can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or in combinations of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more them. The term “data processing apparatus” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document) , in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code) . A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this document can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit) . Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random-access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

While this patent document contains many specifics, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this patent document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

Only a few implementations and examples are described, and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.

Claims

A method for wireless communication, comprising:

dropping, by a wireless communication device in response to a collision between a Sounding Reference Signal (SRS) to a network device and a signal to the network device, at least part of the SRS according to a rule,

wherein the rule is at least associated with a time duration within which two or more SRSs that are expected to be coherent;

receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped; and

performing, by the wireless communication device, a data transmission to the network device based on the control information.
A method for wireless communication, comprising:

transmitting, by a network device, control information to a wireless communication device corresponding to at least part of a SRS being dropped in response to a collision between the SRS from the wireless communication device and a signal from the wireless communication device,

wherein the dropping of the SRS is based on a rule that is at least associated with a time duration within which two or more SRSs that are expected to be coherent, and

receiving, by the network device, a data transmission from the wireless communication device based on the control information.
The method of claim 1 or 2, wherein the time duration comprises a maximum allowed distance in time between two SRSs that are expected to be coherent.
The method of any of claims 1 to 3, wherein the time duration comprises a predefined value.
The method of any of claims 1 to 4, wherein the time duration is determined based on at least one of: a subcarrier space, or a capability of the wireless communication device.
The method of any of claims 1 to 5, wherein the SRS is mapped onto one or more groups of symbols, wherein each one of the one or more groups of symbols comprises multiple symbols, wherein a first part of the multiple symbols of one of the one or more groups of symbols collides with the signal to the network device, and wherein a remaining part of the multiple symbols of one of the one or more groups of symbols does not collide with the signal to the network device.
The method of claim 6, wherein the rule specifies that only the first part of the multiple symbols of one of the one or more groups of symbols is dropped upon determining that the remaining part of the multiple symbols of one of the one or more groups of symbols is combinable with other one or more symbols carrying SRS located within the time duration before or after the remaining part of the multiple symbols of one of the one or more groups of symbols.
The method of claim 6 or 7, wherein the rule specifies that all of the multiple symbols of one of the one or more groups of symbols are dropped upon determining that the remaining part of the multiple symbols of one of the one or more groups of symbols is not combinable with other one or more symbols carrying SRS located within the time duration before or after the remaining part of the multiple symbols.
The method of any of claims 7 or 8, wherein the other one or more symbols carrying SRS is part of multiple symbols of another one of the one or more groups of symbols.
The method of any of claims 1 to 9, wherein whether the wireless communication device adopts the rule is further based on a time point at which information indicating the collision is received by the wireless communication device.
The method of claim 10, wherein the information indicating the collision comprises at least one of: a Downlink Control Information (DCI) triggering the SRS, a Medium Access Control (MAC) Control Element (CE) triggering the SRS, a DCI triggering the signal to the network device, or a MAC CE triggering the signal to the network device.
The method of claim 10 or 11, wherein the wireless communication device adopts the rule upon determining that the information indicating the collision is received no later than K time units before the collision, wherein K is a positive integer.
The method of any of claims 10 to 12, wherein the wireless communication device adopts a default approach of either dropping all of the multiple symbols of one of the one or more groups of symbols or dropping at least part the multiple symbols of one of the one or more groups of symbols upon determining that the information indicating the collision is received later than K time units before the collision, wherein K is a positive integer.
The method of claim 12 or 13, wherein K is a predefined value.
The method of any of claims 12 to 14, wherein K is determined based on at least one of: a subcarrier spacing, or a capability of the wireless communication device.
The method of any of claims 1 to 15, wherein whether the wireless communication device adopts the rule is further based on a parameter codebookSubset carried in a Radio Resource Configuration (RRC) signaling.
The method of claim 16, wherein the wireless communication device adopts the rule upon determining that the parameter codebookSubset is set to fullyAndPartialAndNonCoherent, and otherwise the wireless communication device adopts a default approach of either dropping all of the multiple symbols of one of the one or more groups of symbols or dropping at least part the multiple symbols of one of the one or more groups of symbols.
The method of claim 16, wherein the wireless communication device adopts the rule upon determining that the parameter codebookSubset is set to fullyAndPartialAndNonCoherent or partialAndNonCoherent, and otherwise the wireless communication device adopts a default approach of either dropping all of the multiple symbols of one of the one or more groups of symbols or dropping at least part the multiple symbols of one of the one or more groups of symbols.
The method of any of claims 1 to 18, wherein whether the wireless communication device adopts the rule is further based on a number of coherent groups.
The method of claim 19, wherein the wireless communication device adopts the rule upon determining that the number of coherent groups is less than 8, and otherwise the wireless communication device adopts a default approach of either dropping all of the multiple symbols of one of the one or more groups of symbols or dropping at least part the multiple symbols of one of the one or more groups of symbols.
The method of any of claims 1 to 20, wherein whether the wireless communication device adopts the rule is further based on a parameter codebookType carried in a Radio Resource Configuration (RRC) signaling.
The method of claim 21, wherein the wireless communication device adopts the rule upon determining that the parameter codebookType is set to codebook1, and otherwise the wireless communication device adopts a default approach of either carried in a Radio Resource Configuration (RRC) signaling.
Th method of claim 21, wherein the wireless communication device adopts the rule upon determining that the parameter codebookType is set to codebook1, codebook2, or codebook3, and otherwise the wireless communication device adopts a default approach of either either dropping all of the multiple symbols of one of the one or more groups of symbols or dropping at least part the multiple symbols of one of the one or more groups of symbols.
A method for wireless communication, comprising:

dropping, by a wireless communication device in response to a collision between a Sounding Reference Signal (SRS) to a network device and a signal to the network device, at least part of the SRS;

receiving, by the wireless communication device, control information from the network device corresponding to the at least part of the SRS being dropped; and

performing, by the wireless communication device in response to the dropping of the at least part of the SRS, a data transmission to the network device based on at least a time duration within which an SRS and a data transmission to the network device are expected to be coherent.
A method for wireless communication,

transmitting, by a network device, control information to a wireless communication device corresponding to at least part of a Sounding Reference Signal (SRS) being dropped in response to a collision between the SRS from the wireless communication device and a signal from the wireless communication device; and

receiving, by the network device, a data transmission from the wireless communication device based on at least a time duration within which an SRS and a data transmission from the wireless communication device are expected to be coherent.
The method of claim 24 or 25, wherein the time duration comprises a maximum allowed distance in time domain between an SRS and a data transmission that are expected to be coherent.
The method of any of claims 24 to 26, wherein the time duration comprises a predefined value.
The method of any of claims 24 to 27, wherein the time duration is determined based on at least one of: a subcarrier space, or a capability of the wireless communication device.
The method of any of claims 24 to 28, wherein the control information is ignored and a default precoding matrix is used for performing the data transmission upon determining that there exists only part of an SRS or no SRS within the time duration before a first symbol of the data transmission.
The method of claim 29, wherein the default precoding matrix comprises one of candidate precoding matrices corresponding to a parameter codebookSubset carried in RRC signaling that is set to nonCoherent, a number of coherent groups being equal to 8, or a parameter codebookType that is set to codebook4.
The method of claim 29 or 30, wherein a number of layers of the default precoding matrix is equal to 1.
The method of any of claims 24 to 28, wherein the control information comprises information determined based on at least one of: a parameter codebookSubset, a number of coherent antenna groups, or a parameter codebookType, upon determining that there exists only part of an SRS or no SRS within the time duration before a first symbol of the data transmission.
The method of claim 32, wherein the wireless communication device expects a precoding matrix indicated by the control information is one of candidate precoding matrices corresponding to a parameter codebookSubset that is set to nonCoherent, a number of coherent group being equal to 8, or a parameter codebookType that is set to codebook4.
The method of claim 32 or 33, wherein the control information indicates that a number of layers corresponding to a precoding matrix is no larger than a threshold.
A method for wireless communication, comprising:

determining, by a wireless communication device or a network device, a time duration within which two or more SRSs to the network device that are expected to be coherent.
A method for wireless communication, comprising:

determining, by a wireless communication device or a network device, a time duration within which an SRS to the network device and a data transmission to the network device are expected to be coherent.
A communication apparatus, comprising at least one processor configured to implement a method recited in any one or more of claims 1 to 36.
A computer program product having code stored thereon, the code, when executed by at least one processor, causing the at least one processor to implement a method recited in any one or more of claims 1 to 36.