WO2018227478A1

WO2018227478A1 - Sps enhancement considering granularity of symbol-level intervals

Info

Publication number: WO2018227478A1
Application number: PCT/CN2017/088450
Authority: WO
Inventors: Naizheng ZHENG; Yuantao Zhang
Original assignee: Nokia Technologies Oy; Nokia Technologies (Beijing) Co., Ltd.
Priority date: 2017-06-15
Filing date: 2017-06-15
Publication date: 2018-12-20

Abstract

First signaling configures a UE for a semi-persistent scheduling of first resources. The first resources have a semi-persistent scheduling interval. Second signaling configures the UE for a semi-persistent scheduling of second resources. The second resources have a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval. Communication occurs between a network and the user equipment using the first resources and the second resources. Methods, apparatus, programs, and computer program products are disclosed.

Description

SPS ENHANCEMENT CONSIDERING GRANULARITY OF SYMBOL-LEVEL INTERVALS

TECHNICAL FIELD

This invention relates generally to scheduling of resources in a wireless network and， more specifically， relates to semi-persistent scheduling of resources in the wireless network.

BACKGROUND

This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued， but are not necessarily ones that have been previously conceived， implemented or described. Therefore， unless otherwise explicitly indicated herein， what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section. Abbreviations that may be found in the specification and/or the drawing figures are defined below， after the main part of the detailed description section.

Semi-persistent scheduling had been specified in LTE/LTE-Anetworks since early 3GPP evolution releases， with the main purpose of reducing control channel overhead for voice over IP (VoIP) -based services. VoIP traffic has the characteristic of periodically generated small sized packets， which are generated at short and regular intervals. This traffic has to be scheduled for both uplink and downlink.

The PDCCH carries all allocation information for both the downlink and uplink shared channels， PDSCH and PUSCH respectively. Each allocation is carried as Downlink Control Information (DCI) . Since the PDCCH is limited size， there is a limit as to how many DCIs can be carried in a subframe. This limits the number of UEs which can receive an allocation for that subframe when using dynamic scheduling， and therefore potentially limits the number of UEs having VoIP traffic.

In order to avoid a lot of downlink assignment and uplink grants to support， e.g.， VoIP， the SPS feature significantly reduces the heavy load on PDCCH by performing minimum downlink assignments and uplink grants. In short， SPS allocates radio resources for a long period of time to eNB-served SPS UEs. Therefore， UE is not required to request resources in each (s) TTI， where the transmission control overhead is saved/minimized. This allows for more UEs that have VoIP traffic or other traffic needing regular intervals. This scheduling is semi-persistent in the sense that an eNB can change the resource allocation type or location if required for link adaptation or other factors.

BRIEF SUMMARY

This section is intended to include examples and is not intended to be limiting.

In an exemplary embodiment， a method comprises： configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval； configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and communicating with the user equipment using the first resources and the second resources.

An additional example of an embodiment includes a computer program， comprising code for performing the method of the previous paragraph， when the computer program is run on a processor. The computer program according to this paragraph， wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.

In another exemplary embodiment， an apparatus comprises： means for configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval； means for configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and means for communicating with the user equipment using the first resources and the second resources.

An example of an apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to， with the one or more processors， cause the apparatus to perform at least the following： configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval； configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and communicating with the user equipment using the first resources and the second resources.

An example of a computer program product includes a computer-readable storage medium bearing computer program code embodied therein for use with a computer. The computer program code includes： code for configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval； code for configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and code for communicating with the user equipment using the first resources and the second resources.

In a further exemplary embodiment， a method comprises： receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval； receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and communicating by the user equipment with the wireless network using the first resources and using the second resources.

An example of an apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to， with the one or more processors， cause the apparatus to perform at least the following： receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval； receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and communicating by the user equipment with the wireless network using the first resources and using the second resources.

In a further exemplary embodiment， an apparatus comprises： means for receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval； means for receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and means for communicating by the user equipment with the wireless network using the first resources and using the second resources.

An example of a computer program product includes a computer-readable storage medium bearing computer program code embodied therein for use with a computer. The computer program code includes： code for receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval； code for receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and code for communicating by the user equipment with the wireless network using the first resources and using the second resources.

BRIEF DESCRIPTION OF THE DRAWINGS

In the attached Drawing Figures：

FIG. 1 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced；

FIG. 2A is an example illustrating RRC-configured SPS interval of lms for 2os (two OFDM symbols) sTTI operation for seven subframes；

FIG. 2B is an example illustrating RRC-configured SPS interval of every second sTTI for 2os (two OFDM symbols) sTTI operation for seven subframes；

FIG. 3 illustrates a scenario where the symbol-level SPS resources of FIG. 2B are not fully used and how this might be scheduled；

FIGS. 4-7 illustrate examples of using both RRC-configured SPS interval and symbol-level SPS intervals to schedule SPS resources， in accordance with exemplary embodiments；

FIG. 8 is a logic flow diagram performed by a base station for SPS enhancement considering granularity of symbol-level intervals， and illustrates the operation of an exemplary method or methods， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments；

FIG. 9 is an illustration of first resources for SPS scheduling and second resources that have a transmission pattern within the first resources and within and outside the first resources；

FIG. 10A is an illustration of SPS configuration on a subframe basis；

FIG. 10B is an illustration of SPS configuration on a slot basis； and

FIG. 11 is a logic flow diagram performed by a user equipment for SPS enhancement considering granularity of symbol-level intervals， and illustrates the operation of an exemplary method or methods， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

The word “exemplary” is used herein to mean “serving as an example， instance， or illustration. ” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

The exemplary embodiments herein describe techniques for SPS enhancement considering granularity of symbol-level intervals. Additional description of these techniques is presented after a system into which the exemplary embodiments may be used is described.

Turning to FIG. 1， this figure shows a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced. In FIG. 1， a user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless， typically mobile device that can access a wireless network. The UE 110 includes one or more processors 120， one or more memories 125， and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver， Rx， 132 and a transmitter， Tx， 133. The one or more buses 127 may be address， data， or control buses， and may include any interconnection mechanism， such as a series of lines on a motherboard or integrated circuit， fiber optics or other optical communication equipment， and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a SPS module 140， comprising one of or both parts 140-1 and/or 140-2， which may be implemented in a number of ways. The SPS module 140 may be implemented in hardware as SPS module 140-1， such as being implemented as part of the one or more processors 120. The SPS module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example， the SPS module 140 may be implemented as SPS module 140-2， which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance， the one or more memories 125 and the computer program code 123 may be configured to， with the one or more processors 120， cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with eNB 170 via a wireless link 111.

The eNB (evolved NodeB) 170 is a base station (e.g.， for LTE， long term evolution) that provides access by wireless devices such as the UE 110 to the wireless network 100. The eNB 170 includes one or more processors 152， one or more memories 155， one or more network interfaces (N/W I/F (s) ) 161， and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver， Rx，162 and a transmitter， Tx， 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The eNB 170 includes a SPS module 150， comprising one of or both parts 150-1 and/or 150-2， which may be implemented in a number of ways. The SPS module 150 may be implemented in hardware as SPS module 150-1， such as being implemented as part of the one or more processors 152. The SPS module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example， the SPS module 150 may be implemented as SPS module 150-2， which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance， the one or more memories 155 and the computer program code 153 are configured to， with the one or more processors 152， cause the eNB 170 to perform one or more of the operations as described herein. The one or more network interfaces 161 communicate over a network such as via the

links

176 and 131. Two or more eNBs 170 communicate using， e.g.， link 176. The link 176 may be wired or wireless or both and may implement， e.g.， an X2 interface.

The one or more buses 157 may be address， data， or control buses， and may include any interconnection mechanism， such as a series of lines on a motherboard or integrated circuit， fiber optics or other optical communication equipment， wireless channels， and the like. For example， the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195， with the other elements of the eNB 170 being physically in a different location from the RRH， and the one or more buses 157 could be implemented in part as fiber optic cable to connect the other elements of the eNB 170 to the RRH 195.

The wireless network 100 may include a network control element (NCE) 190 that may include MME (Mobility Management Entity) /SGW (Serving Gateway) functionality， and which provides connectivity with a further network， such as a telephone network and/or a data communications network (e.g.， the Internet) . The eNB 170 is coupled via a link 131 to the NCE 190. The link 131 may be implemented as， e.g.， an S1 interface. The NCE 190 includes one or more processors 175， one or more memories 171， and one or more network interfaces (N/W I/F (s) ) 180， interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to， with the one or more processors 175， cause the NCE 190 to perform one or more operations.

The wireless network 100 may implement network virtualization， which is the process of combining hardware and software network resources and network functionality into a single， software-based administrative entity， a virtual network. Network virtualization involves platform virtualization， often combined with resource virtualization. Network virtualization is categorized as either external， combining many networks， or parts of networks， into a virtual unit， or internal， providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented， at some level， using hardware such as

processors

152 or 175 and

memories

155 and 171， and also such virtualized entities create technical effects.

The computer

readable memories

125， 155， and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology， such as semiconductor based memory devices， flash memory， magnetic memory devices and systems， optical memory devices and systems， fixed memory and removable memory. The computer

readable memories

125， 155， and 171 may be means for performing storage functions. The

processors

120， 152， and 175 may be of any type suitable to the local technical environment， and may include one or more of general purpose computers， special purpose computers， microprocessors， digital signal processors (DSPs) and processors based on a multi-core processor architecture， as non-limiting examples. The

processors

120， 152， and 175 may be means for performing functions， such as controlling the UE 110， eNB 170， and other functions as described herein.

In general， the various embodiments of the user equipment 110 can include， but are not limited to， cellular telephones such as smart phones， tablets， personal digital assistants (PDAs) having wireless communication capabilities， portable computers having wireless communication capabilities， image capture devices such as digital cameras having wireless communication capabilities， gaming devices having wireless communication capabilities， music storage and playback appliances having wireless communication capabilities， Internet appliances permitting wireless Internet access and browsing， tablets with wireless communication capabilities， as well as portable units or terminals that incorporate combinations of such functions.

Having thus introduced one suitable but non-limiting technical context for the practice of the exemplary embodiments of this invention， it is helpful before describing the exemplary embodiments with greater specificity to provide an overview of current SPS techniques.

In legacy SPS， a UE is pre-configured by the eNB with the SPS-C-RNTI (besides the regular C-RNTI) and a periodicity. Once configured， the UE receives/transmits the DL/UL data at the configured periodicity. For example， if a UE is configured with SPS-C-RNTI and periodicity of 20 subfiames， then the UE receives the data every 20ms with SPS-C-RNTI and receives normal DL data in other subframes. During SPS， RB allocations， modulation and coding schemes remain fixed for the current SPS configuration. If any radio link condition changes， the new SPS configurations are sent on PDCCH (e.g.， thus the scheduling is “semi-persistent” and not persistent) . Any HARQ re-transmission will be separately scheduled using normal dynamic scheduling. When a downlink DCI masked by C-RNTI is received in the subframe marked for SPS data transmission， the UE follows the dynamic scheduling at that subframe and does not use the radio resource configured by SPS. The radio resource for SPS is overridden by dynamic scheduling.

The semi-persistent scheduling transmission has four steps， outlined below.

The first step is configuration of semi-persistent parameters. The eNB can configure the UE with SPS at any time， but typically this is done at the time of dedicated bearer establishment for the VolP service. SPS can be configured/re-configured by RRC at any time using SPS-Config. This SPS-Config includes the configuration for semiPersistSchedC-RNTI (SPS-C-RNTI) ， SPS-ConfigDL and SPS-ConfigUL. SPS can be configured only in the uplink (sps-ConfigUL) ， or in the downlink (sps-ConfigDL) or in both directions. The SPS parameter is configured to the UE by an RRC connection setup message， some of which is as follows (as described in more detail in 3GPP TS 36.331， see 3GPP TS 36.331 V14.2.2 (2017-04)) ：

1) semiPersistSchedC-RNTI.

2) semiPersistSchedIntervalUL， which may include the following： ENUMERATED {10ms， 20ms， 32ms， 40ms， 64ms， 80ms， 160ms， 320ms， 640ms } ； impliciReleaseAfter ENUMERATED {e2， e3， e4， e8 } ； and twoIntervalsConfig ENUMERATED {true} .

3) semiPersistSchedIntervalDL， which may include the following： ENUMERATED {10ms， 20ms， 32ms， 40ms， 64ms， 80ms， 160ms， 320ms， 640ms } ； and numberOfConfSPS-Processes INTEGER (1 ... 8) .

Note that， in LTE Rel-13， the minimum supported SPS interval is down to 1ms.

A second step is activation of semi-persistent scheduling. SPS configuration and activation are two different things. Configuration of SPS does not mean that the UE can start using SPS grants/assignments. Instead， the eNB first configures the UE with SPS and then activates the same. Soon after the UE is configured with SPS-C-RNTI， the UE is configured by higher layers to decode PDCCH with CRC scrambled by the SPS-C-RNTI. A UE shall monitor PDCCH with CRC scrambled by the SPS-C-RNTI in every subframe， as the eNB can activate/re-activate/release SPS at any time using downlink control information (DCI) .

DCI Format 0 (zero) is used to activate/release SPS in UL； DCI Formats 1/1A/2/2A/2B/2C are used to activate SPS in DL. In order to release SPS in DL， only DCI Format 1A can be used. The received DCI format on SPS-C-RNTI can be a grant/assignment for a retransmission or for activation/re-activation/release of SPS. 3GPP TS 36.213 (e.g.， see 3GPP TS 36.213 V14.2.0 (2017-03) ) has tabulated the validation procedure for activation/re-activation/release of SPS. A UE shall validate an SPS assignment PDCCH only if all the following conditions are met：

a) CRC parity bits obtained for the PDCCH payload are scrambled with the SPS C-RNTI； and

b) The new data indicator field is set to ‘0’ (zero) .

In case of DCI formats 2， 2A， 2B and 2C， the new data indicator field refers to the one for the enabled transport block.

Validation is achieved if all the fields for the respective used DCI format are set according to Table 9.2-1 or Table 9.2-1A in 3GPP TS 36.213 (see， e.g.， 3GPP TS 36.213 V14.2.0 (2017-03) ) . If validation is achieved， the UE shall consider the received DCI information accordingly as a valid SPS activation or release. If validation is not achieved， the received DCI format shall be considered by the UE as having been received with a non-matching CRC.

The third step is transmission of semi-persistent scheduling on uplink and downlink. After configuring SPS in the UL direction， the eNB can send DCI Format 0 on SPS-C-RNTI to activate the SPS in UL direction. After receiving an activation command， the UE should consider that the uplink grant has been configured and should consider sequentially that the Nth grant occurs in the subframe for which the below condition satisfies the following： (10 *SFN + subframe) ＝ [ (10 *SFN_start time + subframe_start time) + N *semiPersistSchedIntervalUL] modulo 10240， where SFN_start time and subframe_start time are the SFN and subframe， respectively， at the time the configured uplink grants were (re-) initialized.

So， the UE shall use the grant provided in the SPS activation DCI Format 0 once every semiPersistSchedIntervalUL subframes and shall transmit PUSCH using this grant. If there is no data to be transmitted， a multiplexing and assembly entity shall provide MAC PDU containing zero MAC SDU to be transmitted on Semi-Persistent Scheduling resource. The UE shall clear the configured uplink grant immediately after implicitReleaseAfter number of consecutive new MAC PDUs， each containing zero MAC SDUs， on the Semi-Persistent Scheduling resource. This is referred as an implicit release of the UL SPS configured grant. After this， the UE shall not use this configured grant for new transmissions at the occasions satisfying the above equation. Note that retransmissions for Semi-Persistent Scheduling can continue after clearing the configured uplink grant. The eNB can also explicitly send DCI Format 0 to indicate SPS release. Upon receiving DCI Format 0 which indicates SPS release， the UE should clear the configured uplink grant.

After configuring SPS in the DL direction， the eNB can send DCI Format 1/1A/2/2A/2B/2C on SPS-C-RNTI to activate the SPS in the DL direction. From this point on， the UE should consider that the downlink assignment has been configured and should consider sequentially that the Nth assignment occurs in the subframe for which the below condition satisfies the following： (10 *SFN + subframe) ＝ [ (10 *SFN_start time + subframe_start time) + N *semiPersistSchedIntervalDL] modulo 10240， where SFN_start time and subframe_start time are the SFN and subframe， respectively， at the time the configured downlink assignments were (re-) initialized.

The UE shall use this configured assignment once in every semiPersistSchedlntervalDL subframes and decode PDSCH (no corresponding PDCCH) .

In order to transmit HARQ response (Ack/Nack) on PUCCH， the UE would need to calculate frequency resources. In the dynamic scheduling case， a PDCCH (DCI) is present， so the UE calculates Ack/Nack resources based on the CCE index carrying the PDCCH. For the SPS case， from the DCI format indicating DL SPS activation， the TPC command for PUCCH field shall be used as an index to one of the four PUCCH resource values (nlPUCCH-AN-PersistentList) configured by RRC. If the eNB wants to release configured assignment without releasing RRC configuration， it would explicitly send DCI Format 1A to indicate SPS release. Upon receiving DCI Format 1A which indicates SPS release， the UE should clear the configured downlink assignment.

Another important aspect is the HARQ process ID calculation. In case of dynamic scheduling， the corresponding DCI format indicates the HARQ process ID， whereas in the case of SPS， there is no PDCCH corresponding to PDSCH. The HARQ process ID needs to be calculated based on the following equation： HARQ Process ID ＝ [floor (CURRENT_TTI/semiPersistSchedIntervalDL) ] modulo numberOfConfSPS-Processes， where CURRENT_TTI ＝ [ (SFN *10) + subframe number] . Current TTI is the TTI in which PDSCH has been received on the configured assignment

Step four is the release of semi-persistent scheduling. The eNB can explicitly release SPS without releasing SPS RRC configuration.

The following notes are also to be observed：

1) When semi-persistent scheduling for uplink or downlink is disabled by RRC， the corresponding configured grant or configured assignment shall be discarded；

2) Semi-persistent scheduling is supported on the PCell only；

3) The UE should clear any configured downlink assignments and uplink grants when timeAlignmentTimer expires or during MAC reset or when UE has transmitted the scheduling request for a maximum number of times (dsr-TransMax) ； and

4) Except for handover or releasing SPS， E-UTRAN does not reconfigure sps-Config (RRC) when there is a configured downlink assignment or a configured uplink grant.

In the ongoing LTE/LTE-A network evolution， latency reduction had been approved in RAN-plenary#67. See Ericsson， Huawei， “New SI proposal： Study on Latency reduction techniques for LTE” ， RP-150465， 3GPP TSG RAN Meeting #67， Shanghai， China， March. 9 -12， 2015. From the PHY-layer aspect， an SI of shorter TTI (sTTI) and reduced processing time was approved. In RAN1 Rel-13， SI discussions started from RAN1#83 and concluded in RAN1#85. The conclusions of the SI phase were captured in 3GPP TR 36.881 (e.g.， see 3GPP TR 36.881 V14.0.0 (2016-06) ) and it suggested that processing time and TTI length reduction are necessary in order to improve the latency of physical layer radio in LTE networks. Following as expected and agreed in RAN#72 that the WI discussions of sTTI have started from RAN1#86 in Rel-14 targeted for both FDD LTE and TD-LTE. See Ericsson， “New Work Item on shortened TTI and processing time for LTE” ， RP-161299， 3GPP TSG RAN Meeting #72， Busan， Korea， June 13 -16， 2016. The corresponding WI studies of sTTI are ongoing in 3GPP RAN1， further and continuing sTTI study will be conducted in Rel-15 standardization work.

As noted in above， currently supported minimum SPS interval is 1ms as specified in LTE/LTE-A Rel-13， and now with the ongoing shorter TTI study in Rel-15， one question involves how to support and specify the symbol-level SPS operation， which is still an open issue.

The main motivation for SPS enhancements with sTTI operation is for the purpose of saving transmission overhead， where large transmission overhead impacts the sTTI performance that has been identified in the SI phase of the sTTI study. With symbol-level SPS interval or triggering of multi-sTTI scheduling for consecutive sTTIs， symbol-level SPS could very much help of overall transmission overhead reduction for sTTI operation.

In the exemplary embodiments herein， solutions are provided on， e.g.， how to provide symbol-level SPS operation. The examples are not limited to LTE/LTE-A sTTI and， e.g.， a similar or the same proposal may be applied to the mini-slot in 5G NR， or general grant-free transmission in 3GPP standards.

The inventors have realized that a legacy SPS procedure could be applied to symbol-level SPS with sTTI operation. Assume， for instance， symbol-level SPS with sTTI is operated based on a legacy SPS procedure. See FIG. 2A and FIG. 2B， with an example of 2-os (two OFDM symbols) sTTI， where FIG. 2A assumes the RRC-configured SPS interval of 1ms for 2os sTTI operation， and separately FIG. 2B assumes RRC-configured SPS interval of every second sTTI for 2os sTTI operation. Each of these figures shows seven subframes 250， K (subframe 250-k) through K+6 (subframe 250- (k+6) ) ， of 1ms duration each in the time domain.

In more detail， it is assumed in these figures that the 2os sTTI pattern of {3， 2， 2， 2， 2， 3} is used， therefore there are six sTTIs (1， 2， 3， 4， 5， and 6) per 1ms plotted. That is， the sTTI numbered as 1 has three OFDM symbols； each of the sTTIs numbered 2 through 5 has two OFDM symbols； and the sTTI numbered as 6 has three OFDM symbols. This is a total of 14 OFDM symbols， which is typical for a 1ms subframe 250. It should be noted that， in a more general case， if one assumes a 2os sTTI pattern of {2， 2， 2， 2， 2， 2， 2} ， there will be seven sTTIs per 1ms. The exemplary embodiments herein are not limited by the assumed 2os sTTI pattern assumption of {3， 2， 2， 2， 2， 3} and either {3， 2， 2， 2， 2， 3} or {2， 2， 2， 2， 2， 2， 2} (or even something different) may be applied.

In the example of FIG. 2A， the assumed RRC-configured SPS interval of 1ms for 2os sTTI operation means that symbol-level SPS-dedicated monitoring/reception is performed at all configured SPS resources of the first sTTI in each of the subframes 250. That is， for the RRC-configured SPS interval 230 of 1ms， the legacy SPS can be operated (reference 210) for sTTI operation in each first 2os TTI (e.g.， labeled as 2os sTTI numbered 1 in subframe 250-k and is the same for the other subframes 250- (k+1) through 250- (k+6) ) .

For FIG. 2B， the starting point for assumes that the RRC-configured SPS interval can be operated in symbol-level granularity. From a 3GPP standardization perspective， it requires further work in 3GPP RAN2 to agree on finer granularity (below 1ms) of the RRC-configured SPS interval. Thus， the RRC-configured SPS interval 240 is illustrated as being 1ms， but as illustrated by reference 220， the legacy SPS is operated for sTTI operation at an effective rate of every other 2os sTTI (e.g.， labeled as 2os sTTI numbered as 1， 3 and 5 in subframe 250-k and is the same for the other subframes 250- (k+1) through 250- (k+6) ) .

If symbol-level SPS is conducted via RRC-configuration as shown in FIG. 2B， then the UE 110 will perform symbol-level SPS-dedicated monitoring/reception at all configured SPS resources as previously described. Practically， if the dense configured symbol-level SPS resources are not fully used， the legacy specified DCI with SPS activation/re-activation/release could require handling the ‘turning-on’ or ‘turning-off’ of configured SPS resources as shown in FIG. 3. As illustrated by FIG. 3， in reference 310， the SPS for sTTI operation are every other 2os sTTI as in FIG. 2B. However， the SPS release command 320， in sTTI 1 of subframe 250- (k+1) ， releases

sTTIs

3 and 5 in subframe 250- (k+1) and sTTI 1 in subframe 250- (k+2) . That is， those sTTIs are not used for SPS. The SPS release command 330， in sTTI 6 of subframe 250- (k+2) ， releases

sTTIs

1， 3， and 5 from subframe 250- (k+3) .

One issue that is not mentioned in legacy SPS is multi-sTTI scheduling via dynamic DCI. With one straightforward alternative， the multi-scheduling grant can be sent at any sTTI (i.e.， either SPS sTTI or normal sTTI) . Further， scheduling of the following consecutive sTTIs can be performed with a single multi-scheduling assignment/grant， as shown in FIG. 3. Specifically， the multi-sTTI scheduling 340， occurring in sTTI 3 of subframe 250- (k+3) ， schedules SPS for

sTTIs

4， 5， and 6 in subframe 250- (k+4) and

sTTIs

1， 2， and 3 in subframe 250- (k+5) . The multi-sTTI scheduling 350， occurring in sTTI 6 of subframe 250- (k+5) ， schedules SPS for sTTIs 1 through 6 in subframe 250- (k+6) . If the indicated multi-scheduling assignment/

grant

340， 350 overlaps with the SPS resources， then the overlapped SPS resources are simply ‘overwritten’ by the multi-scheduling assignment/

grant

340， 350.

Moreover， for symbol-level SPS operation via FIG. 2A and FIG. 3， sometimes this operation may easily create the issue of dedicated SPS resource wasting if not all SPS resources are fully utilized. Furthermore， frequent SPS resource activation/release via DCI may require large transmission control overhead. As a different approach， proposals in the exemplary embodiments below can be conducted for more spectrum efficient and flexible symbol-level SPS operation.

Assume the RRC-configured SPS interval is kept to operate in the legacy granularity interval of minimum 1ms as shown in FIG. 2A， and symbol-level SPS interval could be configured only when needed， i.e.， via dynamic DCI or in activation DCI. Dynamic DCI is meant to mean use of existing DCI， but with added new indication bits. Activation DCI is meant to mean a new kind of DCI format for the purpose of symbol-level SPS activation/deactivation. It should be noted that it is not required to specify a new RRC-configuration for symbol-level SPS interval in RAN2.

New indication bits in DCI may be used for the symbol-level SPS interval indication. For example， with two indication bits， the indications might be as follows：

1) The bits 00 indicate a normal sTTI operation (that is， perform regular dynamic sTTI scheduling) ；

2) The bits 01 indicate an SPS interval of every 3rd sTTI；

3) The bits 10 indicate an SPS interval of every 2nd sTTI； and

4) This bits 11 indicate multi-sTTI scheduling of the following consecutive sTTIs.

The use of two indication bits is merely one example， as are the choice of bit combinations used to indicate the corresponding sTTI scheduling.

An example is shown in FIG. 4， where symbol-level SPS interval of every second sTTI is enabled at some of the RRC-configured 1ms SPS interval via DCI. Seven subframes 250-k through 250- (k+6) are shown. In this example， the legend illustrates that different patterns are used to illustrate different resources： the pattern for reference 440 indicates RRC-configured SPS resources； the pattern for reference 450 indicates normal TTI resources； the pattern for reference 460 indicates DCI-indicated symbol-level SPS resources； and reference 470 indicates an overlapped SPS resource between an RRC-controlled resource and a DCI-indicated resource.

The RRC-configured SPS resources are in the first sTTI (numbered 1) in each of the subframes 250-k through 250- (k+6) . Normal TTI resources 450 are indicated by a variety of sTTIs in each subframe 250. For instance， subframe 250-k has normal TTI resources 450 in sTTIs numbered 2， 4， and 6， and subframes 250- (k+1) and 250- (k+3) have normal TTI resources 450 in sTTIs numbered 2-6. In fact， reference 420 indicates that no symbol-level SPS occurs within RRC-configured 1ms SPS interval for subframes 250- (k+1) and 250- (k+3) . Reference 410 indicates symbol-level SPS interval occurs within the RRC-configured 1ms SPS interval. That is， the DCI-indicated symbol-level SPS resources 460 occur through the following. A DCI indication 480-1 has been sent by the eNB 170 in sTTI numbered 1 of subframe 250-k， and this indicates the subsequent DCI-indicated symbol-level SPS resources 460 are located in sTTIs numbered 3 and 5 in subframe 250-k. A DCI indication 480-2 has been sent by the eNB 170 in sTTI numbered 1 of subframe 250- (k+2) ， and this indicates the subsequent DCI-indicated symbol-level SPS resources 460 are located in sTTIs numbered 3 and 5 in subframe 250- (k+2) . It should also be noted that a DCI indication 480-3 has been sent by the eNB 170 in sTTI numbered 1 of subframe 250- (k+4) ， and this indicates the subsequent DCI-indicated symbol-level SPS resources 460 are located in sTTIs numbered 3 and 5 in subframes 250- (k+4) and 250- (k+5) . In this example， there is one overlapped SPS resource (see reference 430) between an RRC-controlled resource and a DCI-indicated resource， and is shown occurring at the sTTI numbered 1 in subframe 250- (k+4) .

In FIG. 5， an example of symbol-level multi-sTTI scheduling is enabled at some of the RRC-configured 1ms SPS intervals via DCI. In this example， in reference 510， (symbol-level) multi-sTTI scheduling within RRC-configured 1ms SPS interval for both subframes 250-and 250- (k+2) . That is， a DCI indication 580-1 has been sent by the eNB 170 in the sTTI numbered 1 of the subframe 250-k， and the DCI indication 580-1 indicates that sTTIs 2 through 6 are DCI-indicated symbol-level SPS resources 460 in the subframe 250-k. Similarly， a DCI indication 580-2 has been sent by the eNB 170 in the sTTI numbered 1 of the subframe 250- (k+2) ， and the DCI indication 580-2 indicates that sTTIs 2 through 6 are DCI-indicated symbol-level SPS resources 460 in the subframe 250- (k+2) . This also occurs for a DCI indication 580-3， sent by the eNB 170 in the sTTI numbered 1 of the subframe 250- (k+4) ， and the DCI indication 580-3 indicates that sTTIs 2 through 6 are DCI-indicated symbol-level SPS resources 460 in the subframes 250- (k+4) and 250- (k+5) . This example also has an overlapped SPS resource (see reference 430) between RRC-configured and DCI-indicated resources in the sTTI numbered 1 in the subframe 250- (k+5) . Note that the DCI indications 580-1 and 580-2 inform the UE of multi-sTTI scheduling for one subframe. However， the DCI indication 580-3 informs the UE of multi-sTTI scheduling for two subframe. The one or two (or perhaps more) subframes may be communicated to the UE， e.g.， in DCI via a number of mechanisms， such as a repetition transmission factor.

In FIG. 6， this figure shows a mixed scenario of triggered symbol-level SPS interval of every second sTTI and triggered multi-sTTI scheduling at different RRC-configured 1ms SPS intervals. Reference 610 indicates (symbol-level) multi-sTTI scheduling within RRC-configured 1ms SPS interval is used to create DCI-indicated symbol-level SPS resources 460 in sTTIs 2 through 6 for subframes 250-k and 250- (k+2) . Note the same (symbol-level) multi-sTTI scheduling within RRC-configured hns SPS interval is used to create DCI-indicated symbol-level SPS resources 460 in sTTIs 2 through 6 for subframes 250- (k+4) and 250- (k+5) . Meanwhile， as indicated by reference 620， the symbol-level SPS interval within RRC-configured 1ms SPS interval are used to create DCI-indicated symbol-level SPS resources 460 in sTTIs numbered 3 and 5 in subframes 250- (k+3) and 250- (k+6) .

Moreover， in FIGS 4， 5 and 6， it is generally assumed that the configuration duration of symbol-level SPS via DCI indication is within the RRC-configuration SPS interval of 1ms. For more dynamic symbol-level configuration， the configuration duration of symbol-level SPS can be also provided via DCI messages 480 and 580 as shown in FIGS. 4 and 5， respectively. For the overlapped SPS resources 470 between RRC-configured and DCI-indicated resources， it is simply assumed that the RRC-configured SPS resource is ‘overwritten’ by the DCI-indicated resource configuration.

Furthermore， one general question is the following： which DCI format should carry these new indication bits for symbol-level SPS operation？ The straightforward solution is to add on top of all or some of existing DCI formats for sTTI operations. This solution might bring larger transmission overhead， which might impact sTTI operation. As an alternative， a new DCI format with smaller size could also be considered and introduced for the purpose of symbol-level SPS operation.

Moreover， for UE monitoring of this dynamic DCI， which carries the new indication bits for symbol-level SPS operation， generally this dynamic DCI can be transmitted on all/every sTTIs， i.e.， both SPS sTTI and normal sTTI. However， such dynamic solution could practically bring a quite large transmission overhead for symbol-level SPS interval indications. As an alternative， a UE may be configured (e.g.， either via RRC or in the activation DCI) with a pattern interval， where this configured pattern interval is mainly used for the purpose of UE monitoring for symbol-level SPS activation/deactivation or multi-sTTI scheduling triggering.

An example is shown in FIG. 7， where the RRC-configured SPS resource interval (see reference 710) is 1ms， and a new separate pattern can also be configured to the UE for the purpose of symbol-level SPS activation/deactivation and multi-sTTI scheduling triggering. This new separate pattern 780 is indicated by reference 720， where an RRC-configured interval is shown for symbol-level SPS triggering and/or multi-sTTI scheduling. The legend also indicates that the new pattern 780 configured to the UE for symbol-level SPS DCI-indication monitoring is highlighted with thick bars around the applicable sTTIs. Note that the applicable sTTIs can be any of the

resources

440， 450， or 460 (or also 470， though no sTTIs have an overlapped SPS resource in this example) . In this case， the new introduced pattern 780 may provide finer activation/deactivation interval for symbol-level SPS or multi-sTTI scheduling triggering.

Turning to FIG. 8， this figure is a logic flow diagram performed by a base station for SPS enhancement considering granularity of symbol-level intervals. This figure illustrates the operation of an exemplary method or methods， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments. The blocks in this figure are assumed to be performed by a base station (or other network element) such as the eNB 170 under control at least in part by the SPS module 150. For ease of reference， the eNB 170 will be used.

FIG. 8 assumes there is only one SPS process which includes two signalings， one for first resources and the other one for second resources. The first and second signalings are used to let the UE 110 know the (time domain) first and second resources for this SPS process.

In block 810， the eNB 170 configures via first signaling a user equipment 110 for a semi-persistent scheduling of first resources. The first resources have a semi-persistent scheduling interval.

The eNB 170 in block 820 configures via second signaling the user equipment for a semi-persistent scheduling of second resources. The second resources have a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval. As illustrated by block 825， the second resources may have a transmission pattern of the second resources within the first resources， outside the first resources， or both within the first resources and outside the first resources. Examples of this are illustrated by FIG. 9. The eNB 170 in block 830 communicates with the user equipment using the first resources and the second resources.

Referring to FIG. 9， this figure is an illustration of first resources for SPS scheduling and second resources that have a transmission pattern within the first resources and within and outside the first resources. Reference may also be made to FIG. 8. The SPS interval in FIG. 9 is the RRC-configured SPS interval 930， of which three such intervals 930-1， 930-2， and 930-3 are shown. That is， the RRC-configured SPS interval 930 is one interval that repeats three times in this example. The first resources (see reference 940) contain the subframes 250-1， 250-2， and 250-3， which are based on the configured RRC-configured SPS interval 930 (e.g.， 930-1， 930-2， and 930-3， respectively) and are the first subframe 250 in each interval 930.

In block 820 of FIG. 8， second signaling is used for semi-persistent scheduling of second resources. In one example of FIG. 9， the second resources have (see reference 950) a transmission pattern 980-1 of every second sTTI in the first resources， see

sTTIs

1， 3， and 5 in subframes 250-1 and 250-2. The second resources are scheduled within the RRC-configured SPS interval 930 (see block 820 of FIG. 8) ， although they are also within the first resources (subframes 250-1 and 250-2) . This is an illustration of the second resources having (see reference 910 of FIG. 9) a transmission pattern 980-1 within the first resources (see also block 825 of FIG. 8) .

FIG. 9 illustrates another example， where the second resources have (see reference 920 of FIG. 9) a transmission pattern 980 not only in the first resources. See also block 825 of FIG. 8， where the second resources (sTTIs) have a transmission pattern both within the first resources and outside the first resources. In FIG. 9， it can be seen that the second resources (sTTI) have (see block 950) a transmission pattern 980-1 of every second sTTI in the first resources， see

sTTIs

1， 3， and 5 in subframe 250-3. However， the second resources (sTTIs) have (see block 960) a transmission pattern 980-2 of resources other than in the first resources， as every second sTTI in subframe 250-4 (which is not part of the first resources and is therefore outside the first resources but in the RRC-configured SPS interval 930-3) is part of a transmission pattern 980-2.

As an example that may be added to the examples of FIGS. 8 and 9， the semi-persistent scheduling interval is based on a long transmission time unit and the transmission pattern is based on a short transmission time unit. The short transmission time unit is shorter in time than a time of the long transmission time unit. For instance， the long transmission time unit may be the RRC-configured SPS interval 930， and the short transmission time unit may be an sTTI.

As a further example， the configuring via second signaling a user equipment for a semi-persistent scheduling of second resources is performed using radio resource control signaling in the first resources. The second signaling performs one of activation of use of the transmission pattern of the second resources within the first resources， deactivation of the transmission pattern of the second resources within the first resources， or triggering of a transmission pattern comprising multiple short transmission time units.

As another example， one of the following may be true： the long transmission time unit is a subframe and the short transmission time unit is a part of a subframe， the part shorter than the subframe in the first transmission time limit； or the long transmission time unit is a slot and the short transmission time unit is a mini-slot or a symbol.

FIGS. 10A and 10B illustrate such possibilities. Specifically， FIG. 10A is an illustration of SPS configuration on a subframe basis. In this example， the RRC-configured SPS interval 930 is 20ms (see reference 1010， wherein the configured first resources with the subframe are 1ms of every 20ms) . The RRC-configured SPS interval 930 is repeated as intervals 930-1， 930-2， and 930-3. The first resources (see reference 940) contain the subframes 250-1， 250-2， and 250-3 based on the configured SPS interval 930. That is， only the first subframe 250 in the configured SPS interval 930 is used for the first resources. The subframes 250-1， 250-2 and 250-3 are the long transmission time units. The second resources (see reference 1050) are a single sTTI in the first resources. The single sTTIs in the subframes 250-1， 250-2 and 250-3 are the short transmission time units.

FIG. 10B is an illustration of SPS configuration on a slot basis. In this example， as per reference 1020， the configured first resources are on a slot basis， with 0.5ms of every 20ms dedicated to the first resources. The slots 1030-1， 1030-2， and 1030-3 are the first slots in the subframes 250-1， 250-2 and 250-3 and are 0.5 ms in duration. The slots 1030-1， 1030-2， and 1030-3 in the subframes 250-1， 250-2 and 250-3 are the long transmission time units. The second resources (see reference 1050) are a single sTTI in the first resources. The single sTTIs in the slots 1030-1， 1030-2， and 1030-3 are the short transmission time units.

As a further example， the transmission pattern may have a form of one of the following：

a selected one of the short transmission time units；

a set of consecutive short transmission time units；

a set of periodic short transmission time units； or

a set of non-periodic short transmission time units.

Another example is an example suitable for use with any of the examples above. In this example， the first signaling comprises radio resource control signaling， and the second signaling comprises radio resource control signaling comprising an indication of the transmission pattern. This example also comprises transmitting on a current short transmission time interval in at least the second resources one or both of the following： an indication triggering the semi-persistent scheduling of the second resources for the current short transmission time interval； and an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow the current short transmission time interval.

Another example that may be used with any of the above is where the first signaling comprises radio resource control signaling and where the second signaling comprises a downlink control information message on a physical downlink control channel. Additionally， the downlink control information message may be signaled in a dynamic downlink control information message or in an activation downlink control information message.

Another example that may be used with the examples in the previous paragraph is where the downlink control information message comprises an indication of both the symbol-level interval and an indication of activation of the semi-persistent scheduling of the second resources， and where configuring via second signaling the user equipment for the semi-persistent scheduling of second resources comprises signaling the downlink control information message every current semi-persistent scheduling interval with an indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval.

A further example that may be used with the example in the previous paragraph includes where the indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval comprises one of the following：

an indication of a normal short transmission time interval operation；

an indication of a semi-persistent scheduling interval of every third short transmission time interval；

an indication of semi-persistent scheduling interval of every second short transmission time interval； or

an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow a short transmission time interval in which the downlink control information message occurs.

Another example suitable for use for any of the above is where a first resource and a second resource overlap for a selected symbol-level interval and wherein the communicating further comprises overwriting the first resource for the selected symbol-level interval with the second resource.

Turning to FIG. 11， this figure is a logic flow diagram performed by a user equipment for SPS enhancement considering granularity of symbol-level intervals， and illustrates the operation of an exemplary method or methods， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments. The blocks in FIG. 11 are assumed to be performed by the UE 110 under control of the SPS module 140， at least in part.

In block 1110， the UE 110 receives， from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval. In block 1120， the UE 110 receives， from the wireless network， second signaling for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval. Block 1125 indicates the second resources may have a transmission pattern of the second resources within the first resources， outside the first resources， or both within the first resources and outside the first resources. In block 1130， the UE 110 communicates with the wireless network using the first resources and the second resources.

FIG. 11 is referred to in the additional examples below as Example 13. Example 13. A method， comprising： receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval； receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and communicating by the user equipment with the wireless network using the first resources and using the second resources.

Example 14. The method of example 13， wherein the second resources have a transmission pattern， in the semi-persistent scheduling interval， within the first resources， outside the first resources， or both within the first resources and outside the first resources.

Example 15. The method of examples 13 or 14， wherein the semi-persistent scheduling interval is based on a long transmission time unit and the transmission pattern is based on a short transmission time unit， wherein the short transmission time unit is shorter in time than a time of the long transmission time unit.

Example 16. The method of example 15， wherein：

the receiving second signaling for a semi-persistent scheduling of second resources comprises receiving radio resource control signaling in the first resources， and the second signaling indicates one of activation of use of the transmission pattern of the second resources within the first resources， deactivation of the transmission pattern of the second resources within the first resources， or triggering of a transmission pattern comprising multiple short transmission time units.

Example 17. The method of example 15， wherein one of the following is true： the long transmission time unit is a subframe and the short transmission time unit is a part of a subframe， the part shorter than the subframe in the first transmission time limit； or the long transmission time unit is a slot and the short transmission time unit is a mini-slot or a symbol.

Example 18. The method of any one of examples 15 to 17， wherein the transmission pattern has a form of one of the following： a selected one of the short transmission time units； a set of consecutive short transmission time units； a set of periodic short transmission time units； or a set of non-periodic short transmission time units.

Example 19. The method of any one of examples 13 to 18， wherein：

the first signaling comprises radio resource control signaling；

the second signaling comprises radio resource control signaling comprising an indication of the transmission pattern； and

the method further comprises receiving on a current short transmission time interval in at least the second resources one or both of the following：

an indication triggering the semi-persistent scheduling of the second resources for the current short transmission time interval； and

an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow the current short transmission time interval.

Example 20. The method of any one of examples 13 to 19， wherein：

the first signaling comprises radio resource control signaling； and

the second signaling comprises a downlink control information message on a physical downlink control channel.

Example 21. The method of example 20， wherein the downlink control information message is signaled in a dynamic downlink control information message or in an activation downlink control information message.

Example 22. The method of any one of examples 20 or 21， wherein：

the downlink control information message comprises an indication of both the symbol-level interval and an indication of activation of the semi-persistent scheduling of the second resources； and

receiving via second signaling the user equipment for the semi-persistent scheduling of second resources comprises receiving the downlink control information message every current semi-persistent scheduling interval with an indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval.

Example 23. The method of example 22， wherein the indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval comprises one of the following：

an indication of a normal short transmission time interval operation；

Example 24. The method of any one of examples 13 to 23， wherein a first resource and a second resource overlap for a selected symbol-level interval and wherein the first resource for the selected symbol-level interval has been overwritten with the second resource.

A further example is an apparatus comprising：

means for configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval；

means for configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

means for communicating with the user equipment using the first resources and the second resources.

Another example is the apparatus of the previous paragraph， further comprising means for performing any of the methods described above for the base station. A further example is a base station comprising the apparatus of this or the previous paragraph.

An additional example is an apparatus comprising：

means for receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval；

means for receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

means for communicating by the user equipment with the wireless network using the first resources and using the second resources.

A further example is the apparatus of the previous paragraph， further comprising means for performing any of the methods for the user equipment described above. An additional example is a user equipment comprising the apparatus of this or the previous paragraph.

An additional example is a communication system comprising an apparatus according to any of the base stations and user equipment described above.

Another example is a computer program comprising program code for executing the method according to any of the examples above. The computer program according to this paragraph is another example， wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.

A further example is an apparatus comprising：

at least one processor； and

at least one memory including computer program code，

the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to perform at least the following：

configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval；

configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

communicating with the user equipment using the first resources and the second resources.

In another example， an apparatus comprises：

at least one processor； and

at least one memory including computer program code，

receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval；

receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

communicating by the user equipment with the wireless network using the first resources and using the second resources.

Without in any way limiting the scope， interpretation， or application of the claims appearing below， a technical effect of one or more of the example embodiments disclosed herein is more flexibility for operation of symbol-level SPS. For instance， the SPS interval of 1 ms via current specified RRC-configuration can be re-used， and the symbol-level SPS may be only enabled when needed. By doing so， the over-booking of symbol-level SPS can be minimized， and this could also provide flexibility with enabling of either symbol-level SPS transmission or multi-sTTI scheduling transmission. Furthermore， the standardization effort in RAN2 can also be avoided to define new RRC-configuration SPS interval.

Embodiments herein may be implemented in software (executed by one or more processors) ， hardware (e.g.， an application specific integrated circuit) ， or a combination of software and hardware. In an example embodiment， the software (e.g.， application logic， an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document， a “computer-readable medium” may be any media or means that can contain， store， communicate， propagate or transport the instructions for use by or in connection with an instruction execution system， apparatus， or device， such as a computer， with one example of a computer described and depicted， e.g.， in FIG. 1. A computer-readable medium may comprise a computer-readable storage medium (e.g.，

memories

125， 155， 171 or other device) that may be any media or means that can contain， store， and/or transport the instructions for use by or in connection with an instruction execution system， apparatus， or device， such as a computer. A computer-readable storage medium does not comprise propagating signals.

If desired， the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore， if desired， one or more of the above-described functions may be optional or may be combined.

Although various aspects of the invention are set out in the independent claims， other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims， and not solely the combinations explicitly set out in the claims.

It is also noted herein that while the above describes example embodiments of the invention， these descriptions should not be viewed in a limiting sense. Rather， there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows：

3GPP third generation partnership program

ACK or Ack acknowledgement

A/N acknowledgement /negative acknowledgement

RB resource block

CCE control channel element

CRC cyclic redundancy check

C-RNTI cell radio network temporary identifier

DCI downlink control information

DL downlink

DMRS demodulation reference signal

eNB (or eNodeB) evolved Node B (e.g.， an LTE base station)

E-UTRAN evolved universal terrestrial radio access network

FDD frequency division duplexing

HARQ hybrid automatic retransmission request

ID identification

I/F interface

IP Internet protocol

LTE long term evolution

LTE-A LTE advanced

MAC medium access control

MME mobility management entity

ms milliseconds

NACK or Nack non-acknowledge

NCE network control element

NR new radio

N/W network

OFDM orthogonal frequency division multiplexing

OS or os OFDM symbol

pcell or PCell primary cell

PDCCH physical downlink control channel

PDSCH physical downlink shared channel

PDU protocol data unit

PHY physical (layer)

PRB physical resource block

PUSCH physical uplink control channel

PUSCH physical uplink shared channel

RAN radio access network

RAN1 RAN WG1 (Radio layer 1) is responsible for the

specification of the physical layer of the radio Interface

for UE， UTRAN， Evolved UTRAN， and beyond

RAN2 RAN WG2 is in charge of the Radio Interface

architecture and protocols (MAC， RLC， PDCP) ， the

specification of the Radio Resource Control protocol， the

strategies of Radio Resource Management and the

services provided by the physical layer to the upper

layers

Rel release

RRC radio resource control

RRH remote radio head

RS reference signal

RV redundancy version

Rx receiver

scell or SCell secondary cell

SC-FDMA single carrier frequency division multiple access

SFN subframe number

SGW serving gateway

SI study item

sPDSCH short PDSCH

SPS semi-persistent scheduling

sPUCCH short PUCCH

sPUSCH short PUSCH

TPC transmitter power control

sTTI short TTI

TSG technical specification group

TTI transmission time interval

Tx transmitter

UCI uplink control information

UE user equipment (e.g.， a wireless， typically mobile device)

VoIP voice over IP

WG working group

WI work item

Claims

A method， comprising：

configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval；

configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

communicating with the user equipment using the first resources and the second resources.
The method of claim 1， wherein the second resources have a transmission pattern， in the semi-persistent scheduling interval， within the first resources， outside the first resources， or both within the first resources and outside the first resources.
The method of claims 1 or 2， wherein the semi-persistent scheduling interval is based on a long transmission time unit and the transmission pattern is based on a short transmission time unit， wherein the short transmission time unit is shorter in time than a time of the long transmission time unit.
The method of claim 3， wherein：

the configuring via second signaling a user equipment for a semi-persistent scheduling of second resources is performed using radio resource control signaling in the first resources， and the second signaling performs one of activation of use of the transmission pattern of the second resources within the first resources， deactivation of the transmission pattern of the second resources within the first resources， or triggering of a transmission pattern comprising multiple short transmission time units.
The method of claim 3， wherein one of the following is true：

the long transmission time unit is a subframe and the short transmission time unit is a part of a subframe， the part shorter than the subframe in the first transmission time limit； or

the long transmission time unit is a slot and the short transmission time unit is a mini-slot or a symbol.
The method of any one of claims 3 to 5， wherein the transmission pattern has a form of one of the following：

a selected one of the short transmission time units；

a set of consecutive short transmission time units；

a set of periodic short transmission time units； or

a set of non-periodic short transmission time units.
The method of any one of claims 1 to 6， wherein：

the first signaling comprises radio resource control signaling；

the second signaling comprises radio resource control signaling comprising an indication of the transmission pattern； and

the method further comprises transmitting on a current short transmission time interval in at least the second resources one or both of the following：

an indication triggering the semi-persistent scheduling of the second resources for the current short transmission time interval； and

an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow the current short transmission time interval.
The method of any one of claims 1 to 7， wherein：

the first signaling comprises radio resource control signaling； and

the second signaling comprises a downlink control information message on a physical downlink control channel.
The method of claim 8， wherein the downlink control information message is signaled in a dynamic downlink control information message or in an activation downlink control information message.
The method of any one of claims 8 or 9， wherein：

the downlink control information message comprises an indication of both the symbol-level interval and an indication of activation of the semi-persistent scheduling of the second resources； and

configuring via second signaling the user equipment for the semi-persistent scheduling of second resources comprises signaling the downlink control information message every current semi-persistent scheduling interval with an indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval.
The method of claim 10， wherein the indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval comprises one of the following：

an indication of a normal short transmission time interval operation；

an indication of a semi-persistent scheduling interval of every third short transmission time interval；

an indication of semi-persistent scheduling interval of every second short transmission time interval； or

an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow a short transmission time interval in which the downlink control information message occurs.
The method of any one of claims 1 to 11， wherein a first resource and a second resource overlap for a selected symbol-level interval and wherein the communicating further comprises overwriting the first resource for the selected symbol-level interval with the second resource.
A method， comprising：

receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval；

receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

communicating by the user equipment with the wireless network using the first resources and using the second resources.
The method of claim 13， wherein the second resources have a transmission pattern， in the semi-persistent scheduling interval， within the first resources， outside the first resources， or both within the first resources and outside the first resources.
The method of claims 13 or 14， wherein the semi-persistent scheduling interval is based on a long transmission time unit and the transmission pattern is based on a short transmission time unit， wherein the short transmission time unit is shorter in time than a time of the long transmission time unit.
The method of claim 15， wherein：

the receiving second signaling for a semi-persistent scheduling of second resources comprises receiving radio resource control signaling in the first resources， and the second signaling indicates one of activation of use of the transmission pattern of the second resources within the first resources， deactivation of the transmission pattern of the second resources within the first resources， or triggering of a transmission pattern comprising multiple short transmission time units.
The method of claim 15， wherein one of the following is true：

the long transmission time unit is a subframe and the short transmission time unit is a part of a subframe， the part shorter than the subframe in the first transmission time limit； or

the long transmission time unit is a slot and the short transmission time unit is a mini-slot or a symbol.
The method of any one of claims 15 to 17， wherein the transmission pattern has a form of one of the following：

a selected one of the short transmission time units；

a set of consecutive short transmission time units；

a set of periodic short transmission time units； or

a set of non-periodic short transmission time units.
The method of any one of claims 13 to 18， wherein：

the first signaling comprises radio resource control signaling；

the second signaling comprises radio resource control signaling comprising an indication of the transmission pattern； and

the method further comprises receiving on a current short transmission time interval in

at least the second resources one or both of the following：

an indication triggering the semi-persistent scheduling of the second resources for the current short transmission time interval； and

an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow the current short transmission time interval.
The method of any one of claims 13 to 19， wherein：

the first signaling comprises radio resource control signaling； and

the second signaling comprises a downlink control information message on a physical downlink control channel.
The method of claim 20， wherein the downlink control information message is signaled in a dynamic downlink control information message or in an activation downlink control information message.
The method of any one of claims 20 or 21， wherein：

the downlink control information message comprises an indication of both the symbol-level interval and an indication of activation of the semi-persistent scheduling of the second resources； and

receiving via second signaling the user equipment for the semi-persistent scheduling of second resources comprises receiving the downlink control information message every current semi-persistent scheduling interval with an indication of the symbol-level interval to use for at least the current semi-persistent scheduling interval.
The method of claim 22， wherein the indication of the symbol-level interval to use for

at least the current semi-persistent scheduling interval comprises one of the following：

an indication of a normal short transmission time interval operation；

an indication of a semi-persistent scheduling interval of every third short transmission time interval；

an indication of semi-persistent scheduling interval of every second short transmission time interval； or

an indication of short transmission time interval scheduling of consecutive short transmission time intervals that follow a short transmission time interval in which the downlink control information message occurs.
The method of any one of claims 13 to 23， wherein a first resource and a second resource overlap for a selected symbol-level interval and wherein the first resource for the selected symbol-level interval has been overwritten with the second resource.
An apparatus comprises：

means for configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a senti-persistent scheduling interval；

means for configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

means for communicating with the user equipment using the first resources and the second resources.
The apparatus of claim 25， further comprising means for performing any of the methods of claims 2 to 12.
A base station comprising the apparatus of claims 25 or 26.
An apparatus comprises：

means for receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval；

means for receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

means for communicating by the user equipment with the wireless network using the first resources and using the second resources.
The apparatus of claim 28， further comprising means for performing any of the methods of claims 14 to 24.
A user equipment comprising the apparatus of claims 26 or 27.
A communication system comprising an apparatus according to any of claims 25 or 26 and an apparatus according to any of claims 26 or 27.
A computer program comprising program code for executing the method according to any of claims 1 to 24.
The computer program according to claim 32， wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.
An apparatus comprising：

at least one processor； and

at least one memory including computer program code，

the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to perform at least the following：

configuring via first signaling a user equipment for a semi-persistent scheduling of first resources， the first resources having a semi-persistent scheduling interval；

configuring via second signaling the user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

communicating with the user equipment using the first resources and the second resources.
An apparatus comprising：

at least one processor； and

at least one memory including computer program code，

the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to perform at least the following：

receiving， by a user equipment and from a wireless network， first signaling configuring the user equipment for a first semi-persistent scheduling of first resources， the first semi-persistent scheduling having a semi-persistent scheduling interval；

receiving， by a user equipment and from the wireless network， second signaling a user equipment for a semi-persistent scheduling of second resources， the second resources having a transmission pattern of the second resources within resources to be transmitted within the semi-persistent scheduling interval； and

communicating by the user equipment with the wireless network using the first resources and using the second resources.