WO2021093192A1

WO2021093192A1 - Tracking semi-persistent scheduling transmissions

Info

Publication number: WO2021093192A1
Application number: PCT/CN2020/074596
Authority: WO
Inventors: Wei Gou; Peng Hao; Xianghui HAN
Original assignee: Zte Corporation
Priority date: 2020-02-10
Filing date: 2020-02-10
Publication date: 2021-05-20
Also published as: CN114946245A

Abstract

Methods, apparatus, and systems for tracking the actual number of Semi-Persistent Scheduling (SPS) transmissions performed to reduce signaling overhead are disclosed. In one example aspect, a wireless communication method includes transmitting, by a base station, a configuration of SPS transmissions to a mobile device. The method also includes transmitting, by the base station to the mobile device, an indication of actual SPS transmissions performed based on the configuration.

Description

TRACKING SEMI-PERSISTENT SCHEDULING TRANSMISSIONS

TECHNICAL FIELD

This patent document is directed generally to wireless 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 that monitor and inform the user devices of the actual number of Semi-Persistent Scheduling (SPS) transmissions performed so as to reduce signaling overhead in Hybrid Automatic Repeat request (HARQ) acknowledgement (ACK) feedback.

In one example aspect, a wireless communication method includes transmitting, by a base station, a configuration of semi-persistent scheduling (SPS) transmissions to a mobile device; and transmitting, by the base station to the mobile device, an indication of actual SPS transmissions performed based on the configuration.

In another example aspect, a wireless communication method includes receiving, by a user device, a configuration of semi-persistent scheduling (SPS) transmissions from a base station; and receiving, by the user device from the base station, an indication of actual SPS transmissions performed based on the configuration.

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 set of Semi-Persistent Scheduling (SPS) configurations.

FIG. 2 is a flowchart representation of a wireless communication method in accordance with the disclosed technology.

FIG. 3 is a flowchart representation of another wireless communication method in accordance with the disclosed technology.

FIG. 4 illustrates an example of determining the actual number of SPS transmissions in accordance with the disclosed technology.

FIG. 5 illustrates another example of determining the actual number of SPS transmissions in accordance with the disclosed technology.

FIG. 6A illustrates an example of symbols used for transmitting the actual number of SPS transmissions in the physical layer in accordance with the disclosed technology.

FIG. 6B illustrates another example of symbols used for transmitting the actual number of SPS transmissions in the physical layer in accordance with the disclosed technology.

FIG. 6C illustrates another example of symbols used for transmitting the actual number of SPS transmissions in the physical layer in accordance with the disclosed technology.

FIG. 6D illustrates another example of symbols used for transmitting the actual number of SPS transmissions in the physical layer in accordance with the disclosed technology.

FIG. 6E illustrates another example of symbols used for transmitting the actual number of SPS transmissions in the physical layer in accordance with the disclosed technology.

FIG. 6F illustrates another example of symbols used for transmitting the actual number of SPS transmissions in the physical layer in accordance with the disclosed technology.

FIG. 7 illustrates an example of transmitting a total number of SPS transmissions in the last few SPS transmissions in accordance with the disclosed technology.

FIG. 8 illustrates an example scenario in which eight downlink slots are followed by two uplink slots that support sub-slots.

FIG. 9 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. 10 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. Certain features are described using the example of Fifth Generation (5G) wireless protocol. However, applicability of the disclosed techniques is not limited to only 5G wireless systems.

Currently in 5G communications, semi-persistent scheduling (SPS) transmissions on the Physical Downlink Shared Channel (PDSCH) are scheduled at various periods having a minimum length of one slot. A user equipment (UE) can be configured with up to eight sets of SPS transmissions. The Hybrid Automatic Repeat request (HARQ) acknowledgement (ACK) corresponding to a SPS transmission is currently generated according to the SPS configuration (s) . FIG. 1 illustrates an example set of SPS configurations. A UE is configured with two sets of SPS configurations for two carriers respectively: SPS0 and SPS1 are configured for Carrier0; SPS2 and SPS3 are configured for Carrier1. The HARQ-ACK codebooks of these SPS transmissions are structured as follows:

1. HARQ-ACK1 is formed for SPS transmission 101 of Carrier0 according to the corresponding downlink (DL) slot in which the SPS transmission 101 is located.

2. HARQ-ACK2 is formed for SPS transmission 103 of Carrier0 according to the corresponding DL slot in which the SPS transmission 103 is located.

3. HARQ-ACK3 is formed for SPS transmission 105 of Carrier1 according to the corresponding DL slot in which the SPS transmission 105 is located.

4. SPS transmission 107 of Carrier1 is not performed. However, HARQ NACK is formed nonetheless based on the SPS configuration.

The remaining HARQ-ACKs are formed corresponding to the configured SPS transmissions. When a SPS transmission is not performed (e.g., SPS transmission 109 of Carrier0) , a NACK is formed nonetheless.

In the above HARQ-ACK processing, HARQ-ACK information is generated at each SPS transmission period regardless of whether the SPS transmission is actually performed. When an SPS transmission is not performed at one SPS transmission cycle, the UE does not receive the SPS transmission but still generates HARQ-ACK information as NACK. The HARQ ACKs/NACKs are then concatenated according to predefined rules and a HARQ-ACK codebook is determined accordingly. The NACKs generated for SPS transmissions that have not actually been transmitted thus result in an increase in the HARQ-ACK codebook overhead. When there are a large number of configured SPS transmissions and/or a small SPS transmission period, many NACKs can be generated for SPS transmissions that were not actually performed. Therefore, there remains a need to reduce the HARQ-ACK overhead so that ACKs/NACKs are only generated for the actual SPS transmissions performed. This patent documents discloses techniques that can be implemented in various embodiment to identify the number of SPS transmissions that have actually been performed so as to reduce the amount of HARQ-ACK information that needs to be generated in the HARQ-ACK codebook.

FIG. 2 is a flowchart representation of a wireless communication method 200 in accordance with the disclosed technology. The method 200 includes, at operation 210, transmitting, by a base station, a configuration of semi-persistent scheduling (SPS) transmissions. The method 200 also includes, at operation 220, transmitting, by the base station to the mobile device, an indication of actual SPS transmissions performed based on the configuration. In some embodiments, the indication indicates a number of the actual SPS transmissions that have been performed. In some embodiments, the indication and an actual SPS transmission are transmitted simultaneously. In some embodiments, the indication is transmitted as a Medium Access Control (MAC) control element. In some embodiments, the indication is transmitted as a physical layer indication. In some embodiments, the method includes repeatedly transmitting the indication in case the indication is associated with a last actual SPS transmission. In some embodiments, the indication is represented using L bits, L being a value greater than or equal to 2.

In some embodiments, the indication is transmitted as a Demodulation Reference Signal (DMRS) sequence. In some embodiments, the indication is associated with a sequence number of the DMRS sequence. In some embodiments, a number of actual SPS transmissions performed is M and the indication has a value in a range of 0 to N, M and N being integers greater than or equal to 0. The value of the indication is circularly repeated to represent M actual SPS transmissions. In some embodiments, the method also includes indicating, by the base station to the user device, a total number of the actual SPS transmissions performed.

FIG. 3 is a flowchart representation of a wireless communication method 300 in accordance with the disclosed technology. The method 300 includes, at operation 310, receiving, by a user device, a configuration of semi-persistent scheduling (SPS) transmissions from a base station. The method 300 also includes, at operation 320, receiving, by the user device from the base station, an indication of actual SPS transmissions performed based on the configuration.

In some embodiments, the indication indicates a number of the actual SPS transmissions that have been performed. In some embodiments, the indication and an actual SPS transmission are transmitted simultaneously. In some embodiments, the indication is received as a Medium Access Control (MAC) control element. In some embodiments, the indication is received as a physical layer indication. In some embodiments, the method includes repeatedly receiving the indication in case the indication is associated with a last actual SPS transmission. In some embodiments, the indication is represented using L bits, L being a value greater than or equal to 2.

In some embodiments, the indication is received as a Demodulation Reference Signal (DMRS) sequence. In some embodiments, the indication is associated with a sequence number of the DMRS sequence. In some embodiments, a number of actual SPS transmissions performed is M and the indication has a value in a range of 0 to N, M and N being integers greater than or equal to 0. The value of the indication is circularly repeated to represent M actual SPS transmissions. In some embodiments, the method also includes receiving, the user device from the base station, a total number of the actual SPS transmissions performed.

As further described in the present document, the above-described methods provide means to track the actual number of SPS transmission performed to reduce the number of NACKs generated for HARQ-ACK information, thereby reducing signaling overhead. Some examples of the disclosed techniques are described in the following example embodiments.

Embodiment 1

In some embodiments, the base station sends an indicator indicating the actual number of SPS transmission to the UE. The indication of the actual number of SPS transmissions performed can be transmitted as a MAC CE.

Assuming that a UE is configured with one or more sets of SPS transmissions. For each SPS transmission, a counter can be introduced as the indicator to track the number of actual SPS transmission (s) performed. In some embodiments, when an SPS transmission is to be performed, the counter indicating the number of SPS transmissions that have been performed can be transmitted together with the SPS transmission in a MAC CE. That is, a counter is included in each of the SPS transmission that is performed. This way, after the UE receives the SPS transmission and decodes it, the UE can determine the number of SPS transmissions that have been performed so far based on the MAC CE. When no actual transmission occurs at a particular SPS period, the UE does not receive the MAC CE that includes the count. The UE then can determine whether HARQ ACK/NACK needs to be generated for the SPS transmission (s) to avoid excessive invalid NACKs in the HARQ-ACK codebook.

In some embodiments, the counter can be represented by one or more bits. FIG. 4 illustrates an example of determining the actual number of SPS transmissions in accordance with the disclosed technology. In this example, two bits in a MAC CE can be used to represent the counter. The value of the counter is in a range of [0, 3] and can be circularly repeated to represent a larger number of SPS transmissions. For example, values of 0 to 3 can represent 1st to 4th SPS transmissions (e.g., counter 0: SPS transmission 1, counter 1: SPS transmission 2, …counter 3: SPS transmission 4) . The same values can be circularly repeated to represent 5th to 8th SPS transmissions (e.g., counter 0: SPS transmission 5, …counter 3: SPS transmission 8) . In some embodiments, more bits (e.g., 4 bits) can be used for the counter when the number of configured SPS transmissions in a period is large.

In the example shown in FIG. 4, each SPS configuration of the carrier is given a separate counter. For SPS0, a counter value of ‘00’ is transmitted as a MAC CE with the SPS transmission 401 to indicate that one SPS transmission (the current SPS transmission 401) has been performed at that point. The counter is then incremented to be ‘01’ for SPS transmission 402. SPS transmission 403 is skipped even though it is configured. For SPS transmission 404, the counter is incremented again to indicate that so far three

SPS transmissions

401, 402, 404 have been actually performed. Similarly, for SPS1, a counter value of ‘00’ is transmitted as a MAC CE with SPS transmission 411. SPS transmission 412 is skipped, so a counter value of ‘01’ is transmitted as a MAC CE with SPS transmission 413 to indicate that two

SPS transmissions

411, 413 have been actually performed.

Embodiment 2

In some embodiments, transmissions of the Demodulation Reference Signal (DMRS) can be used as an indicator to indicate the counter. For example, N DMRS sequences are used for the transmissions of the DMRS for each SPS configuration, where N > 0. Each sequence is assigned a sequence number having a value between 0 to N-1. The sequence number corresponds to the counter value (0 to N-1) to indicate the number of SPS transmissions that have been performed (1 to N) . Each SPS configuration of the carrier is given a separate counter.

FIG. 5 illustrates an example of determining the actual number of SPS transmissions in accordance with the disclosed technology. Assuming that there are four defined DMRS sequences (N=4) . Each SPS transmission is associated with a DMRS transmission. For example, a DMRS sequence having a sequence number of 0 is associated with SPS transmission 501. A DMRS sequence having a sequence number of 1 is associated with SPS transmission 502. SPS transmission 503 is skipped, so no DMRS transmission is performed. For SPS transmission 504, a DMRS sequence having a sequence number of 2 is transmitted. When the number of SPS transmissions performed is greater than N, the sequence numbers can be circularly repeated. For example, for SPS transmission 505, a sequence number of 0 is used to indicate that the number of SPS transmissions performed is 5

Embodiment 3

In some embodiments, the counter can also be transmitted as a physical layer indicator. For example, the N bits (N>=1) used to represent the counter can be repeated and modulated to N1 units of resources to be transmitted using part of the physical channel resources for SPS transmissions. The base station and the UE can determine the N1 units of resources according to one of the following ways:

1. In some embodiments, as illustrated in FIG. 6A, the N1 units of resources start at the first symbol 601 after the first DMRS symbol in the resources configured for the SPS transmission. When there are multiple consecutive DMRS symbols, the N1 units of resources start at the first symbol 611 after the last DMRS symbol as illustrated in FIG. 6B. In some embodiments, resource units occupied by DMRS in the frequency domain (e.g., in symbols starting from

symbol

601 or 611 as shown in FIGS. 6A-B) are skipped.

2. In some embodiments, as illustrated in FIG. 6C, the N1 units of resources start at the first DMRS symbol in the resources configured for the SPS transmission. When there are multiple consecutive DMRS symbols, the N1 units of resources start at the last of the consecutive DMRS symbols as shown in FIG. 6D. In some embodiments, resource units occupied by DMRS in the frequency domain are skipped.

3. In some embodiments, the N1 units of resources start at the symbol 621 before the first DMRS symbol of the SPS transmission resources as illustrated in FIG. 6E. When there are multiple consecutive DMRS symbols, the N1 units of resources start at the symbol 631 before the last DMRS as illustrated in FIG. 6F. In some embodiments, resource units occupied DMRS in the frequency domain (e.g., in symbols starting from

symbol

621 or 631 as shown in FIGS. 6E-F) are skipped.

In order to ensure that the counter associated with the last SPS transmission in an SPS period is reliably transmitted and received to determine the HARQ-ACK codebook, the counter can be repeated (e.g., using a repetition factor) to improve reliability.

Embodiment 4

In some embodiments, the HARQ-ACK codebook of multiple SPS transmissions can be constructed differently. To minimize codebook overhead, a counter that tracks the number of actual SPS transmissions for all carriers can be provided.

For example, multiple SPS transmissions of different carriers are organized in sequence according to the chronological order of DL slots. If DL slots of multiple SPS transmissions align in the time domain, the transmissions are organized in order based on the carrier indices. If the carrier indices are the same (e.g., the transmissions are associated with the same carrier) , the transmissions are ordered based on the transmission indices. The counter can track the number of actual SPS transmissions for all carriers. The counter can be transmitted as a MAC CE, as a physical layer indicator, or be associated with a DMRS sequence for each SPS transmission as described in Embodiments 1-3. A HARQ-ACK codebook is then determined based on the all the SPS transmissions for all carriers. In some embodiments, the counter indicates the total number of SPS transmissions transmitted according to different SPS configurations associated with different carriers.

Embodiment 5

In some cases, the last few SPS transmissions are skipped in the SPS period, resulting in incorrect tracking of the number of SPS transmission performed and inaccurate determination of the HARQ-ACK codebook, particularly when multiple SPS configurations are configured for the UE. To address this problem, the base station can transmit a second counter indicating the total number of SPS transmissions (e.g., Count_total) for all SPS configurations in a few SPS transmissions. For example, the base station can transmit Count_total in the last M SPS transmission corresponding to a HARQ-ACK codebook. FIG. 7 illustrates an example of transmitting a total number of SPS transmissions in the last few SPS transmissions in accordance with the disclosed technology. In this example, M=4. The base station transmits Count_total in the last four SPS transmissions 701-704 within the SPS period. The transmission of Count_total can be performed similar to the counter tracking the actual number of SPS transmissions described in Embodiments 1-3.

In some embodiments, the SPS transmissions that carry Count_total are determined based on a time-domain offset B from the beginning of HARQ-ACK transmission on the Physical Uplink Control Channel (PUCCH) . As shown in FIG. 7, the beginning of HARQ-ACK 705 on PUCCH is at time-domain position C. The M (e.g., M=4) number of SPS transmissions (e.g., 701-704) that are prior to the time-domain location (C-B) are used to carry the Count_total. The SPS transmission (s) (e.g., 706) after the time-domain location (C-B) are not used to carry Count_total. The offset value B can be determined based on two values B1 and/or B2. B1 can be one of the following values: T _proc, 1 as defined in 3GPP TS38.214, N, N1, N2, N3, Z, Z’, T _proc, 2 or T _proc, CSI as defined in 3GPP TS38.213, or other predefined values. B2 can be an optional value that is either 0, 1, or 2 symbols according to UE capabilities.

Embodiment 6

When multiple SPS configurations are configured, the base station can determine an SPS transmission pattern (e.g., a bitmap) for the UE to provide HARQ-ACK feedback accordingly. The base station can configure an SPS pattern for the required HARQ-ACK feedback according to the actual service requirement. In some embodiments, priority can be given to periodic services. For example, the SPS pattern is configured according to the service period such that there is no or fewer skipped SPS transmissions. After receiving the SPS pattern, the UE only needs to provide HARQ feedback according to the pattern.

For example, a UE is configured with multiple SPS configurations. The SPS pattern can indicate that some SPS transmissions are skipped due to service periodicity. That is, the SPS pattern indicates the actual number of SPS transmissions to be performed (e.g., according to the service periodicity) . When the UE receives the SPS pattern from the base station, the UE generates corresponding HARQ-ACK feedback according to the pattern to determine the HARQ-ACK codebook, thereby avoiding unnecessary HARQ-ACK information when no transmission actually occurs.

Embodiment 7

Currently the base station transmits a Downlink Control Information (DCI) message to the UE indicating the time-domain location of the HARQ-ACK information. For example, the DCI message includes a value k1 indicating the number of slots between the reception of data on Physical Downlink Shared Channel (PDSCH) and the HARQ-ACK transmission. In particular, the initial slot corresponding to k1=0 is defined to be the slot (can be downlink or uplink slot) on HARQ-ACK carrier that corresponds to the end of PDSCH transmission. Because PDSCH and HARQ-ACK can have different subcarrier spacings and different slot lengths, the number of slots is counted based on slots on the carrier for HARQ-ACK information.

However, the SPS transmission period can be small. The minimum SPS transmission period is currently set at one slot and can potentially become smaller than one slot. As an example, uplink transmissions now support sub-slots. An uplink (UL) slot can be divided into 2 or 7 sub-slots. Each sub-slot can be used to transmit HARQ-ACK information. The value of k1 can be adjusted to be based on sub-slots. For example, an uplink slot is configured to include 7 sub-slots. The value of k1 is sub-slot based. That is, each slot (uplink and/or downlink) is counted as 7 sub-slots even though downlink slots do not support sub-slots.

However, currently the range of k1 value is small (e.g., between 0 to 15) . Changing the value of k1 to be sub-slot based can lead to HARQ-ACK transmission issues when multiple downlink slots are followed by a few uplink sub-slots. FIG. 8 illustrates an example scenario in which eight downlink slots 801-808 are followed by two uplink slots 809-810 supporting sub-slots. The HARQ-ACK is scheduled in sub-slot 6 of uplink slot 810. However, the maximum value of k1 is limited to 15, which corresponds to a downlink slot rather than an uplink slot for HARQ-ACK transmission.

To improve how HARQ-ACK transmission location is determined, in some embodiments, the initial slot corresponding to k1=0 can be defined to be the first uplink slot or special slot on the HARQ-ACK carrier after the end of PDSCH transmission. A special slot here is a slot that includes both uplink and downlink symbols.

The value of k1 can indicate the number of slots after the initial slots. In some embodiments, the number of slots can include downlink, uplink, and/or special slots. In some embodiments, the number of slots can include uplink and/or special slots.

If sub-slots are supported, the value of k1 can indicate the number of sub-slots after the initial slots. In some embodiments, the number of sub-slots can include downlink, uplink, and/or special slots (each slot is counted as 2 or 7 sub-slots) . In some embodiments, the number of sub-slots can include uplink and/or special slots (each slot is counted as 2 or 7 sub-slots) .

Changing the initial slot corresponding to k1=0 to be the first uplink after the end of PDSCH transmission ensures correct indication of HARQ-ACK transmission in an uplink slot even when the value of k1 is restricted to a small range.

Embodiment 8

As discussed in Embodiment 7, the base station transmits to the UE a DCI message that includes a single value k1 indicating the time-domain location of the HARQ-ACK information. That is, HARQ-ACK information corresponding to all PDSCH transmissions is fed back to the base station in a single uplink slot according to k1, potentially leading to performance issues in the PUCCH.

In addition to the k1 value, the base station can configure a correspondence between downlink slot (s) of PDSCH and the uplink slot for HARQ-ACK feedback. For example, referring back to FIG. 8, the first four downlink slots 801-804 correspond to uplink slot 809, and the next four downlink slots 805-808 correspond to uplink slot 810. The base station can indicate the correspondence via a Radio Resource Control (RRC) signaling message. In some embodiments, configuring such correspondence removes the need of having a DCI message indicating k1 --the UE can transmit HARQ-ACK information in slot 809 after receiving data in downlink slots 801-804 and in slot 810 after receiving data in downlink slots 805-808. In some embodiments, the correspondence can be used in conjunction with the DCI indication. When the correspondence is indicated in the RRC signaling message, the UE can ignore k1 value in the DCI signaling (e.g., the k1 value can be invalid, or the DCI signaling may not include the k1 value) . When the correspondence is missing in the RRC signaling message, the UE can continue to use the DCI signaling to determine HARQ-ACK transmissions based on with slots or sub-slots as discussed in Embodiment 7.

FIG. 9 shows an example of a wireless communication system 900 where techniques in accordance with one or more embodiments of the present technology can be applied. A wireless communication system 900 can include one or more base stations (BSs) 905a, 905b, one or

more wireless devices

910a, 910b, 910c, 910d, and a core network 925. A

base station

905a, 905b can provide wireless service to

wireless devices

910a, 910b, 910c and 910d in one or more wireless sectors. In some implementations, a

base station

905a, 905b includes directional antennas to produce two or more directional beams to provide wireless coverage in different sectors.

The core network 925 can communicate with one or

more base stations

905a, 905b. The core network 925 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

wireless devices

910a, 910b, 910c, and 910d. A first base station 905a can provide wireless service based on a first radio access technology, whereas a second base station 905b can provide wireless service based on a second radio access technology. The

base stations

905a and 905b may be co-located or may be separately installed in the field according to the deployment scenario. The

wireless devices

910a, 910b, 910c, and 910d 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. 10 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 1005 such as a base station or a wireless device (or UE) can include processor electronics 1010 such as a microprocessor that implements one or more of the wireless techniques presented in this document. The radio station 805 can include transceiver electronics 1015 to send and/or receive wireless signals over one or more communication interfaces such as antenna 1020. The radio station 1005 can include other communication interfaces for transmitting and receiving data. Radio station 1005 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 1010 can include at least a portion of the transceiver electronics 1015. In some embodiments, at least some of the disclosed techniques, modules or functions are implemented using the radio station 1005. In some embodiments, the radio station 1005 may be configured to perform the methods described herein.

It will be appreciated that the present document discloses techniques that can be embodied in various embodiments to reduce HARQ-ACK signaling overhead on the uplink control channel based on the actual number of SPS transmissions performed. 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 of wireless communication, comprising:

transmitting, by a base station, a configuration of semi-persistent scheduling (SPS) transmissions to a mobile device; and

transmitting, by the base station to the mobile device, an indication of actual SPS transmissions performed based on the configuration.
The method of claim 1, wherein the indication indicates a number of the actual SPS transmissions that have been performed.
The method of claim 1 or 2, wherein the indication and an actual SPS transmission are transmitted simultaneously.
The method of claim 3, wherein the indication is transmitted as a Medium Access Control (MAC) control element.
The method of claim 3, wherein the indication is transmitted as a physical layer indication.
The method of any one or more of claims 1 to 5, comprising:

repeatedly transmitting the indication in case the indication is associated with a last actual SPS transmission.
The method of any one or more of claims 1 to 5, wherein the indication is represented using L bits, L being a value greater than or equal to 2.
The method of claim 1 or 2, wherein the indication is transmitted as a Demodulation Reference Signal (DMRS) sequence.
The method of claim 8, wherein the indication is associated with a sequence number of the DMRS sequence.
The method of any one or more of claims 1 to 9, wherein a number of actual SPS transmissions performed is M and the indication has a value in a range of 0 to N, M and N being integers greater than or equal to 0, and wherein the value of the indication is circularly repeated to represent M actual SPS transmissions.
The method of any one or more of claims 1 to 10, comprising:

indicating, by the base station to the user device, a total number of the actual SPS transmissions performed.
A method for wireless communication, comprising:

receiving, by a user device, a configuration of semi-persistent scheduling (SPS) transmissions from a base station; and

receiving, by the user device from the base station, an indication of actual SPS transmissions performed based on the configuration.
The method of claim 12, wherein the indication indicates a number of the actual SPS transmissions that have been performed.
The method of claim 12 or 13, wherein the indication and an actual SPS transmission are transmitted simultaneously.
The method of claim 14, wherein the indication is received as a Medium Access Control (MAC) control element.
The method of claim 14, wherein the indication is received as a physical layer indication.
The method of any one or more of claims 12 to 16, comprising:

repeatedly receiving the indication in case the indication is associated with a last actual SPS transmission.
The method of any one or more of claims 12 to 17, wherein the indication is represented using L bits, L being a value greater than or equal to 2.
The method of claim 12 or 13, wherein the indication is received as a Demodulation Reference Signal (DMRS) sequence.
The method of claim 19, wherein the indication is associated with a sequence number of the DMRS sequence.
The method of any one or more of claims 1 to 20, wherein a number of actual SPS transmissions performed is M and the indication has a value in a range of 0 to N, M and N being integers greater than or equal to 0, and wherein the value of the indication is circularly repeated to represent M actual SPS transmissions.
The method of any one or more of claims 1 to 21, comprising:

receiving, the user device from the base station, a total number of the actual SPS transmissions performed.
A communication apparatus, comprising a processor configured to implement a method recited in any one or more of claims 1 to 22.
A computer program product having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited in any one or more of claims 1 to 22.