WO2016119232A1

WO2016119232A1 - Methods for determination of repetition number of physical data channel

Info

Publication number: WO2016119232A1
Application number: PCT/CN2015/071980
Authority: WO
Inventors: Min Wu; Tao Chen; Hua-min CHEN
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2015-01-30
Filing date: 2015-01-30
Publication date: 2016-08-04

Abstract

A method to determine a repetition number of a physical data channel for a device under coverage enhancement is disclosed, wherein comprising: determining a repetition number of a physical data channel based on a UE-specific high layer signaling and/or an indicator in downlink control information (DCI); transmitting or receiving the physical data channel based on the determined repetition number. And a method to dynamically adjust repetition number of PDSCH with a report of assisted information is disclosed, wherein comprising: configuring a first repetition number for a transport block; reporting an assisted information related to the decoding result of the transport block; and configuring a second repetition number for another transport block or retransmission of the transport block, wherein the second repetition number may be different from the first repetition number.

Description

METHODS FOR DETERMINATION OF REPETITION NUMBER OF PHYSICAL DATA CHANNEL

TECHNICAL FIELD

This disclosure relates generally to wireless communications and, more particularly, for a device to determine a repetition number of a physical data channel under coverage enhancement.

BACKGROUND

In 3GPP LTE Rel-13 machine type communication (MTC) working item description (WID) , there are three requirements which are respectively low complexity, coverage enhancement and power consumption. For coverage enhancement, a target Maximum Coupling Loss (MCL) of 155.7dBm is proposed for both Rel-13 low complexity MTC UE and other non-MTC UE operating delay tolerant MTC applications. For PUSCH with the bottle-neck of MCL among all physical channels, i.e. 140.7dBm MCL, the target MCL of 155.7dBm means maximum 15dB coverage enhancement. Considering compensation of some coverage loss caused by low complexity, e.g. 3dB transmission power reduction for uplink, it is required to achieve maximum 18dB coverage enhancement. In order to achieve the target of coverage enhancement, repetition is necessary for most physical channels/signals. And many technologies can be used to improve the efficiency of repetition, i.e. reduce the number of repetitions as far as possible, such as cross-subframe channel estimation, increasing DMRS density, uplink PSD boosting, frequency-hopping and so on.

SUMMARY

A method to determine a repetition number of a physical data channel for a device under coverage enhancement is disclosed, wherein comprising: determining a repetition number of a physical data channel based on a UE-specific high layer signaling and/or an indicator in downlink control information (DCI) ； transmitting or receiving the physical data channel based on the determined repetition number. In one embodiment, determining a repetition number of a physical data channel based on a UE-specific high layer signaling further comprising: configuring a set of repetition numbers by the UE-specific high layer signaling, wherein each one repetition number within the set of repetition numbers corresponds to a transport block size (TBS) of the physical data channel； receiving a DCI associated with the physical data channel； determining a TBS of the physical data channel based on the DCI； and determining a repetition number of the physical data channel based on the set of repetition numbers and the TBS. In one embodiment, determining a repetition number of a physical data channel based on an indicator in DCI further comprising: receiving a DCI associated with the physical data channel； and determining a repetition number of the physical data channel based on the value of Repetition Number (RN) field in the DCI. In one embodiment, determining a repetition number of a physical data channel based on a UE-specific high layer signaling and an indicator in DCI further comprising: configuring a set of repetition numbers by the UE-specific high layer signaling, wherein each one within the set of repetition numbers corresponds to a TBS of the physical data channel； receiving a DCI associated with the physical data channel； determining a TBS of the physical data channel based on the DCI； and determining a repetition number of the physical data channel based on the set of repetition numbers, the TBS and the value of repetition number offset (RNO) field in the DCI.

A method to dynamically adjust repetition number of PDSCH with a report of assisted information is disclosed, wherein comprising: configuring a first repetition number for a transport block； reporting an assisted information related to the decoding result of the transport block； and configuring a second repetition number for another transport block or retransmission of the transport block, wherein the second repetition number may be different from the first repetition number. In one example, the assisted information is the actual number of used repetitions for early decoding if the early decoding is successful. In one example, the assisted information is an estimated repetition number required for next retransmission by UE if the transport block is not successfully decoded, wherein the required repetition number is estimated based on a combined SINR of all repetitions of the transport block. In one example, the assisted information is reported jointly with ACK/NACK by PUCCH.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a block diagram illustrating a schematic diagram of a wireless communications system according to one embodiment of the present invention.

FIG. 2 shows an example of determining a repetition number of a physical data channel based on a UE-specific high layer signaling and a predefined table.

FIG. 3 shows an example of determining a repetition number of a physical data channel based on a UE-specific high layer signaling.

FIG. 4 shows an example of determining a repetition number of a physical data channel based on a dedicated DCI field.

FIG. 5 shows an example of determining a repetition number of a physical data channel based on a UE-specific high layer signaling, a predefined table and a dedicated DCI field.

FIG. 6 shows an example of determining a repetition number of a physical data channel based on a UE-specific higher layer signaling and a dedicated DCI field.

FIG. 7 shows an example of determining a repetition number of a physical data channel with a pattern of accumulation.

FIG. 8 shows an example of adaptive repetition number for new data transmission of PDSCH with a report of assisted information.

FIG. 9 shows an example of adaptive repetition number for PDSCH retransmission with a report of assisted information.

FIG. 10 shows an example of adaptive repetition number for retransmission of a physical data channel with a compact DCI design.

DETAILED DESCRIPTION

Several exemplary embodiments of the present disclosure are described with reference to FIGs. 1 through 10. It is to be understood that the following disclosure provides various embodiments as examples for implementing different features of the present disclosure. Specific examples of components and arrangements are described in the following to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various described embodiments and/or configurations.

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. Note that the 3GPP specifications described herein are used to teach the spirit of the invention, and the invention is not limited thereto.

FIG. 1 is a block diagram illustrating a schematic diagram of a wireless communications system according to one embodiment of the present invention. The wireless communications system 100 includes one or more fixed

base infrastructure units

110 and 111, forming one or

more access networks

130 and 131 distributed over a geographical region. The

access network

130 and 131 may be a Universal Terrestrial Radio Access Network (UTRAN) in the WCDMA technology or an E-UTRAN in the Long Term Evolution (LTE) /LTE-Atechnology. The base unit may also be referred to an access point, base station, Node-B, eNode-B (eNB) , or other terminologies used in the art. In some systems, one or more base stations are communicably coupled to a controller forming an access network that is communicably coupled to one or more core networks.

In FIG. 1, one or more

mobile stations

120 and 121 are connected wirelessly to

base stations

110 and 111 for wireless service within a serving area, for example, a cell or within a cell sector. The mobile station may also be called user equipment (UE) , a wireless communication device, terminal or some other terminologies.

Mobile station

120 and 121 send uplink data to

base stations

110 and 111 via

uplink channel

140 and 141 in the time and/or frequency domain. The

serving base station

110 and 111 transmit downlink signals via a

downlink channel

150 and 151.

In one embodiment, the communication system utilizes Orthogonal Frequency Division Multiplexing Access (OFDMA) or a multi-carrier based architecture including Adaptive Modulation and Coding (AMC) on the downlink and next generation single-carrier (SC) based FDMA architecture for uplink transmissions. SC based FDMA architectures include Interleaved FDMA (IFDMA) , Localized FDMA (LFDMA) , DFT-spread OFDM (DFT-SOFDM) with IFDMA or LFDMA. In OFDMA based systems, remote units are served by assigning downlink or uplink radio resources that typically comprises a set of sub-carriers over one or more OFDM symbols. Exemplary OFDMA based protocols include the developing LTE/LTE-Aof the 3GPP standard and IEEE 802.16 standard. The architecture may also include the use of spreading techniques such as multi-carrier CDMA (MC-CDMA) , multi-carrier direct sequence CDMA (MC-DS-CDMA) , Orthogonal Frequency and Code Division Multiplexing (OFCDM) with one or two dimensional spreading, or may be based on simpler time and/or frequency division multiplexing/multiple access techniques, or a combination of these various techniques.

In alternate embodiments, communication system may utilize other cellular communication system protocols including, but not limited to, TDMA or direct sequence CDMA. The disclosure however is not intended to be limited to any particular wireless communication system.

In FIG. 1, the mobile communication network 100 is an OFDM/OFDMA system comprising a base station eNB 110 and eNB 111, and a plurality of mobile station 120 and mobile station 121. When there is a downlink data block to be sent from base station to mobile station, each mobile station gets a downlink resource assignment, e.g., a set of downlink radio resources indicated in downlink control information (DCI) which is transmitted with a physical downlink control channel (PDCCH or EPDCCH) . Thus, mobile stations receive corresponding Physical Downlink Shared Channel (PDSCH) in the set of downlink radio resources. When a UE needs to send an uplink data block to base station, the mobile station gets a grant from the base station that assigns a set of uplink radio resources, i.e. an uplink grant convey by a DCI. Thus, the UE transmits corresponding physical uplink shared channel (PUSCH) in the set of uplink radio resources.

In 3GPP LTE Rel-13 machine type communication (MTC) , there are three requirements which are respectively low complexity, coverage enhancement and power consumption. Coverage enhancement means a better coverage than normal coverage is provided. A target maximum coupling loss (MCL) of 155.7dBm is proposed for both Rel-13 low complexity MTC UE and other non-MTC UE operating delay tolerant MTC applications for both FDD and TDD. In FDD LTE system, MCL of PUSCH is the bottle-neck among all physical channels, i.e. 140.7dBm. Thus, the target MCL of 155.7dBm means (155.7-140.7) ＝ 15dB coverage enhancement for FDD PUSCH. Considering compensation of the coverage loss caused by low complexity, e.g. 3dB loss caused by uplink transmission power reduction, it is required to achieve maximum 18dB coverage enhancement. In order to achieve the target of coverage enhancement, repetition is necessary for most physical channels.

Before performing repetition of a physical channel, the number of repetitions of the physical channel needs to be known by UE. One direct problem is how to determine the repetition number, e.g. semi-static signaling, dynamic signaling, or dynamic adjustment based on a semi-static configured repetition number. In this disclosure, some methods to determine a repetition number of a physical data channel for a UE under coverage enhancement are proposed. The UE may be a MTC UE or a non-MTC UE, and the coverage enhancement may be for a better coverage than a normal LTE coverage or compensation of coverage loss caused by low complexity to achieve a normal LTE overage.

The number of repetitions depends on at least one of coverage gain, physical channel type, transmission mode if the physical channel supports multiple transmission modes, and coding rate if the physical channel supports multiple coding rates. So, repetition number may be very diverse for different levels of coverage gain, different types of physical channel, different transmission modes and different coding rates.

Coverage gain refers to the gap between target MCL and normal MCL. For a given target of MCL, coverage gain depends on physical channel type. Table 1 shows the MCL for different types of physical channel in normal FDD and TDD system. For FDD LTE, a target MCL of 155.7dBm means (155.7-140.7) ＝ 15dB coverage gain for PUSCH and (155.7-145.4) ＝ 10.3dB coverage gain for PDSCH. Therefore, repetition number may be diverse for different types of physical channel.

Table 1. MCL for different types of physical channel (dBm)

Coding rate means the ratio of the number of coded bits to the number of information bits. The number of coded bits is determined by the number of available REs in the allocated resources within a TTI and modulation order, i.e. N_RE*Q_m. For a physical data channel, the information bits are a sum of transport block size (TBS) and CRC length, i.e. TBS+L_CRC. Thus, coding rate of a physical data channel is determined by TBS, modulation order and the number of allocated PRB (s) , i.e. (TBS+L_CRC) / (N_RE*Q_m) . For (E) PDCCH, coding rate is determined by aggregation level and DCI size. Coding rate determines the required SINR at 10％BLER and actual coverage gain which is the gap between the working SINR and the required SINR at 10％BLER. Therefore, repetition number may be diverse for different coding rates.

For a physical data channel under coverage enhancement, the number of allocated PRB (s) and modulation order may be predefined or semi-statically configured. One of the benefits is that the size of resource block assignment (RBA) field and the size of modulation and coding scheme (MCS) field can be reduced. Thus, a compact DCI design can be used to reduce repetition number of the associated physical control channel. For PDSCH repetitions, QPSK modulation and 6 PRBs may always be used to reduce the repetition number of PDSCH wherein 6 RPBs are the maximum allocated resources considering 1.4MHz bandwidth reduction for low complexity MTC UE. For PUSCH repetitions, QPSK modulation and 1 PRB may be used to reduce the repetition number of PUSCH, wherein narrow bandwidth allocation can achieve uplink PSD boosting gain. If the number of PRB (s) is fixed, coding rate is determined only by TBS which is determined only by MCS. Therefore, repetition number depends on TBS, i.e. repetition number may be diverse for different TBSs.

Coverage gain means the gap between actual working SINR and the required SINR at 10％BLER. Under ideal channel estimation, double repetitions can achieve 3dB coverage gain which is contributed by the accumulation of receiving SINR, i.e. energy combining. However, it is difficult to achieve 3dB gain in a practical system due to performance loss of realistic channel estimation. As an increased coverage gain, the repetition number may increase with a much faster speed than the exponential increase. Table 2 shows our simulation results on rough repetition number of PUSCH at 10％BLER under different coverage gains and different coding rates, wherein 1 PRB and QPSK modulation is assumed. Other simulation parameters are as following: 10MHz system bandwidth, 1 transmitter antenna, 2 receiver antennas, EPA 1Hz channel, 100Hz frequency offset and realistic channel estimation. In the simulation, one repetition means one TTI.

Table 2. Repetition number of PUSCH at 10％BLER

From the table, for the case of 32bits TBS, we can see repetition number is increased to 330 from 6 as coverage gain is increased to 15dB from 5dB. For a higher repetition level, more repetitions are required to achieve a given level of SINR gain. For example, to achieve 0.2dB gain at 10％BLER, 1 additional repetition may be required for the case of 32bits TBS and 5dB coverage gain, wherein repetition number is about 6. However, 50 additional repetitions may be required for the case of 32bits TBS and 15dB coverage gain, wherein repetition number is about 300. Therefore, a reasonable step of repetition number may rapidly increase as repetition number increasing, e.g. [1, 2, 3, …, 10] , [100, 110, 120, …, 200] , and [500, 550, 600, …, 1000] .

Under coverage enhancement, UE may be statically located in a non-normal environment with an extremely bad wireless channel condition, e.g. a basement or under water. In this case, the working SINR is mainly impacted by large-scale fading, and small-scale fading may not disturb the ultra-low working SINR. Thus, the coverage gain, i.e. the gap between the working SINR and the minimum required SINR at 10％BLER, may not frequently change. Therefore, repetition number of a physical data channel under a certain coding rate can be semi-statically configured. The semi-static configuration is similar to current PUCCH repetitions, wherein 2, 4 and 6 repetitions are supported for PUCCH in Rel-8 specification.

In one embodiment, a set of repetition numbers of (E) PDCCH are semi-statically configured for each aggregation level and each DCI size, e.g., using a UE-specific high layer signaling to indicate the set of repetition numbers, or an index of repetition level combining with a predefined table wherein a repetition number is specified for each repetition level, each aggregation level and each DCI size. Under coverage enhancement, single DCI size and maximum aggregation level may be used to reduce the number of (E) PDCCH blind decoding, and using the maximum aggregation level can also reduce the number of (E) PDCCH repetitions . In this case, one repetition number corresponding to the single DCI size and the maximum aggregation level is semi-statically configured for PDCCH repetitions.

However, dynamic adjustment of repetition number may be helpful for a physical data channel. At eNB side, the repetition number of PUSCH is selected based on UL measurement, and the repetition number of PDSCH is selected based on report of DL measurement. Under an ultra-low working SINR, the measurement result may not be precise due to serious measurement error, especially for UE side. An actually required repetition number may have a large difference from the selected repetition number based on measurement results. To reduce the difference caused by measurement and a suddenly changed channel quality, a dedicated DCI field related to repetition number can be used to dynamically adjust the repetition number. With the dynamic adjustment, the selected repetition number could be step by step close to the actually required value. Accordingly the system efficiency can be improved since some unnecessary repetitions can be saved. Therefore, it is very helpful to introduce a dedicated indicator in DCI under coverage enhancement. In addition, introducing a dedicated DCI field related to repetition number may be a simple and direct method since repetition number is very diverse for different types of physical channel, different levels of coverage gain, different transmission modes and different coding rates.

For PDSCH repetition, eNB could dynamically configure a matched repetition number for a certain TBS and a certain coverage gain with a dedicated DCI field. Furthermore, eNB could dynamically adjust the repetition number with the dedicated DCI field. And some report of assisted information may be helpful for the dynamic adjustment of repetition number. One type of assisted information is an estimated required repetition number for next retransmission if a transport block is not successfully decoded. Based on the assisted information, the repetition number of next retransmission of the transport block could be dynamically adjusted. The required repetition number could be estimated based on the gap between a combined SINR of all existing repetitions and the required SINR at the point of 10％BLER. Another type of assisted information is an actual number of used repetitions for early decoding if the early decoding is successful. Based on the assisted information, repetition number of next transport block could be dynamically adjusted. Here, early decoding means UE may try decoding before receiving the complete repetitions. If early decoding is successful, remaining repetitions needn’ t to be received, i.e., early termination of PDSCH receiving. Furthermore, an ACK can be immediately reported as long as early decoding is successful, and eNB can terminate transmitting remaining repetitions after receiving the ACK report, i.e. early termination of PDSCH transmission. And the implied information by the occurrence of ACK report, i.e. the actual number of used repetitions for successful decoding can be referenced by eNB to dynamically adjust the repetition number of next transport block.

Similarly, for PUSCH repetition, eNB could dynamically adjust the repetition number based on previous receiving result. Different from the dynamic adjustment of PDSCH repetition number, some report of assisted information is not needed since PUSCH receiving and scheduling are on the same side, i.e. eNB side. So, it may be more easily to implement the dynamic adjustment of PUSCH repetition number. In addition, early termination of PUSCH transmission is very helpful to save the UE power consumption.

In one embodiment, determining a repetition number of a physical data channel based on a UE-specific high layer signaling further comprising: configuring a set of repetition numbers by the UE-specific high layer signaling, wherein each one within the set of repetition numbers corresponds to a transport block size (TBS) of the physical data channel； receiving a DCI associated with the physical data channel； determining a TBS of the physical data channel based on the DCI； and determining a repetition number of the physical data channel based on the set of repetition numbers and the TBS. In one example, the set of repetition numbers is explicitly indicated by the UE-specific high layer signaling. In one example, the set of repetition numbers is determined based on an index of repetition level indicated by the UE-specific high layer signaling and a predefined table specifying a repetition number for each TBS and each repetition level. In one example, the index of repetition level indicated by the UE-specific high layer signaling is dedicated for the physical data channel. In one example, wherein the index of repetition level indicated by the UE-specific high layer signaling is shared by other physical channel with the same transmission direction of the physical data channel, wherein the predefined table also specifies a repetition number of other physical channel for each repetition level.

In one embodiment, determining a repetition number of a physical data channel based on an indicator in DCI further comprising: receiving a DCI associated with the physical data channel； and determining a repetition number of the physical data channel based on the value of repetition number (RN) field in the DCI.

In one embodiment, determining a repetition number of a physical data channel based on a UE-specific high layer signaling and an indicator in DCI further comprising: configuring a set of repetition numbers by the UE-specific high layer signaling, wherein each one within the set of repetition numbers corresponds to a TBS of the physical data channel； receiving a DCI associated with the physical data channel； determining a TBS of the physical data channel based on the DCI； and determining a repetition number of the physical data channel based on the set of repetition numbers, the TBS and the value of repetition number offset (RNO) field in the DCI. In one example, interpreting the value of RNO field depends on the set of repetition numbers configured by the UE-specific high layer signaling and the TBS of the physical data channel.

In one embodiment: configuring a first repetition number for a transport block； reporting an assisted information related to the decoding result of the transport block； and configuring a second repetition number for another transport block or retransmission of the transport block, wherein the second repetition number may be different from the first repetition number. In one example, the assisted information is the actual number of used repetitions for early decoding if the early decoding is successful. In one example, the assisted information is an estimated repetition number required for next retransmission by UE if the transport block is not successfully decoded, wherein the required repetition number is estimated based on a combined SINR of all repetitions of the transport block. In one example, the assisted information is reported jointly with ACK/NACK by PUCCH.

FIG. 2 shows an example of semi-static configuration of repetition number of a physical data channel. In one embodiment, receiving an index of repetition level which is indicated by a UE-specific high layer signaling； receiving a DCI associated with a physical data channel and determining an index of TBS of the physical data channel based on the DCI； determining a repetition number of the physical data channel based on the index of repetition level, the index of TBS and a predefined table wherein each TBS and each repetition level correspond to a repetition number in the predefined table； transmitting or receiving the physical data channel based on the determined repetition number.

In the embodiment in FIG. 2, the predefined table specifies multiple repetition levels corresponding to different levels of coverage gains. Since repetition number depends on TBS, the predefined table specifies a repetition number for each TBS under each repetition level. In other words, one dimension of the predefined table is repetition level, and another dimension is TBS. Using the predefined table, the signaling overhead for configuration of repetition number can be remarkably saved, i.e. just signaling an index of repetition level instead of signaling a set of repetition numbers for all supported TBSs. In one example, under a certain repetition level, the repetition number of a physical data channel may be larger than 1 for a large TBS and equal to 1 for a small TBS, wherein ‘1’ means no repetition.

In one example, the UE-specific high layer signaling and the predefined table in FGI. 2 are dedicated for the physical data channel. In another example, the UE-specific high layer signaling and the predefined table are shared by multiple types of physical channel with the same transmission direction. This is because, under a target MCL, coverage gain can be converted between a physical channel and other physical channel if they are of the same transmission direction. Therefore, the index of repetition level needs to be configured respectively for DL and UL. The configuration of repetition level for DL is based on the report of DL measurements at UE side. And the configuration of repetition level for UL is based on the UL measurements at eNB side.

In one example, a predefined table specifies multiple repetition levels for both physical data channel and physical control channel. A physical control channel and a physical data channel can share the same index of repetition level to determine corresponding repetition number. Thus, the overall signaling overhead for configuration of repetition number can be further reduced. In addition, the number of repetition levels of a physical control channel may be different from that of a physical data channel. This is because maximum coverage gain may be different for different types of physical channel. For example, there are 15 repetition levels for PUSCH and 8 repetition levels for PUCCH considering a MCL target of 155.7dBm and a step of 1dB coverage gain. Under a certain target MCL, PUSCH is repeated meanwhile PUCCH is not repeated since the MCLs supported by the two physical channels are different. In one example, under a certain repetition level, the repetition number may be larger than 1 for a physical data channel and equal to 1 for a physical control channel, wherein ‘1’ means no repetition.

FIG. 3 shows another example of semi-static configuration of repetition number of a physical data channel. In one embodiment, receiving a set of repetition numbers of a physical channel which is indicated by a UE-specific high layer signaling, and each one within the set of repetition numbers corresponds to a TBS of the physical data channel； receiving a DCI associated with the physical data channel and determining a TBS of the physical data channel based on the DCI； determining a repetition number of the physical data channel based on the set of repetition numbers and the TBS； transmitting or receiving the physical data channel based on the determined repetition number.

In the embodiment in FIG. 3, the number of elements within the set of repetition numbers is equal to the number of TBSs supported by the physical data channel, i.e. configuring corresponding repetition number for all TBSs. In one example, if the physical data channel just supports single TBS, the UE-specific high layer signaling indicates one repetition number for the physical data channel. In one example, the configured repetition number of a physical data channel may be larger than 1 for a large TBS and equal to 1 for a small TBS, wherein ‘1’ means no repetition, i.e. normal transmission.

FIG. 4 shows an example of dynamic configuration of repetition number of a physical data channel. In one embodiment, receiving a DCI associated with a physical data channel； determining a repetition number of the physical data channel based on a Repetition Number (RN) field in the DCI； transmitting or receiving the physical data channel based on the determined repetition number.

In the embodiment in FIG. 4, repetition number is dynamically configured by a RN field in the DCI. In one example, the value of RN field is a continuous integer, e.g. 5bits indicates a range of [1, 2, 3, …, 32] repetitions. In one example, the value of RN field is a discrete integer and the interval of two adjacent values rapidly increases as repetition number increasing, e.g. 5bits indicates a range of [1, 2, 3, …, 10, 12, 14, 16, …, 30, 34, 38, 42, …, 70, 80, 90] repetitions. In one example, the value of RN field is a discrete integer and the interval is the constant, e.g. 5bits indicates a range of [4, 8, 12, …, 128] . In the case, the repetition number is of a multiple of 4, wherein each 4 adjacent repetitions use a predefined RV sequence, e.g. 0 2 3 1.

FIG. 5 shows an example of dynamic adjustment of repetition number based on a semi-static configured repetition number. In one embodiment, receiving an index of repetition level which is indicated in a UE-specific high layer signaling； receiving a DCI associated with a physical data channel and determining an index of TBS of physical data channel based on the DCI； determining a rough number of the physical data channel based on the index of repetition level, the index of TBS and a predefined table, wherein each TBS and each repetition level correspond to a repetition number in the predefined table； determining an exact repetition number of the physical data channel based on the rough repetition number and a Repetition Number Offset (RNO) field in the DCI, wherein interpreting the value of RNO field depends on the rough repetition number； transmitting or receiving the physical data channel based on the determined exact repetition number.

FIG. 6 shows another example of dynamic adjustment of repetition number based on a semi-static configured repetition number. In one embodiment, receiving a set of repetition numbers of a physical data channel which is indicated in a UE-specific high layer signaling, and each one within the set of repetition numbers corresponds to a TBS of the physical data channel； receiving a DCI associated with the physical data channel and determining TBS of the physical data channel based on the DCI； determining a rough repetition number of the physical data channel based on the set of repetition numbers and the TBS； determining an exact repetition number of the physical data channel based on the rough repetition number and a Repetition Number Offset (RNO) field in the DCI, wherein interpreting the value of RNO field depends on the rough repetition number； transmitting or receiving the physical data channel based on the determined exact repetition number.

In the embodiments in FIG. 5 and FIG. 6, the repetition number is the sum of the value of RNO field and the rough repetition number. And the value indicated by the RNO field is relatively large for a large TBS or a high repetition level, e.g., the value of RNO field may be [-10, 0, 10, 20] for a large TBS and [-2, 0, 2, 4] for a small TBS under a certain repetition level. In one example, the value of RNO field is [-2*N, -1*N, 0, 2*N] , wherein ‘N’ could be called as step size or repetition granularity. And the value of ‘N’ depends on the rough repetition number. In other words, the value of ‘N’ depends on repetition level and TBS since the rough repetition number is determined by repetition level and TBS. In one example, the value of ‘N’ is configured by a UE-specific high layer signaling. In one example, the value of ‘N’ is implied by the rough repetition number with a predefined rule. For example, if the rough repetition level is within the range [1～20] , the value of ‘N’ is equal to 1. If the rough repetition level is within the range [20～200] , the value of ‘N’ is equal to 4. If the rough repetition level is within the range [200～500] , the value of ‘N’ is equal to 10. In one example, the value of ‘N’ is implied with a predefined table, wherein the predefined table specifies the step size for each repetition level and each TBS.

In one example, the RN field in FIG. 4 or the RNO field in FIG. 5 and FIG. 6 exists just for first transmission and repetition number of retransmission reuses that of first transmission, i.e. non-adaptive repetition number for retransmission. In one example, the RN or RNO field exists for both first transmission and retransmission, i.e. adaptive repetition number for retransmission.

FIG. 7 shows an example of accumulated repetition number of a physical data channel. In one embodiment, determining a set of repetition numbers of a physical data channel which is configured by a UE-specific high layer signaling and each one within the set of repetition numbers corresponds to a TBS of the physical data channel； receiving a RNO field in a DCI associated with the physical data channel, wherein interpreting the value of RNO field depends on the TBS of the physical data channel； receiving a RNO field in a DCI associated with the physical data channel, wherein interpreting the value of RNO field depends on a TBS of the physical data channel which is determined based on the DCI； determining whether the transmission of the physical data channel is the start of an accumulation loop or not； if the transmission is the start of an accumulation loop, determining an exact repetition number for the transmission based on the value of RNO field and a rough repetition number which is determined based on the set of repetition numbers and the TBS of the transmission, otherwise, determining an exact repetition number for the transmission based on the value of RNO field and the repetition number used by previous transmission of the physical data channel with the same TBS of current transmission； transmitting or receiving the physical data channel based on the determined exact repetition number.

In the embodiment in FIG. 7, the accumulation of repetition number is performed within a predefined or semi-statically configured duration, e.g. 10 seconds. The duration may be related to the UE mobility. If the duration expires, another accumulation loop needs to be started. For the start of an accumulation loop, repetition number is determined using the methods in FIG. 5 and FIG. 6, i.e. dynamic adjustment based on a semi-statically configured rough repetition number.

In one example, the accumulation in FIG. 7 could be disabled by a UE-specific high layer signaling, and then determination of repetition number is switched to the method in FIG. 5 or FIG. 6 from the method in FIG. 7, wherein interpreting the value of RNO field may be different under enabled accumulation and disabled accumulation.

FIG. 8 shows an example of adaptive repetition number for DL new data transmission. In one embodiment, receiving a repeated transmission of a first transport block based on a first repetition number； reporting an information on a actual number of used repetitions for early decoding if the early decoding of the first transport block is successful； receiving a DCI associated with a new data transmission of a second transport block, wherein the TBS of the second transport block is the same to the first transport block； determining a second repetition number based on a dedicated indicator in the DCI and it is different from the first repetition number； receiving the repeated transmission of the second transport block based on the second repetition number.

In the embodiment in FIG. 8, repetition number is dynamically adjusted for new data transmission based on the reported assisted information. The adjusted repetition number is determined based on a dedicated DCI field using the methods in FIG. 4, FIG. 5 or FIG. 6. In one example, the TBS of next transport block may be different from the first transport block. The reported assisted information could also be referred to adjust the repetition number for next transport block. The adaptive repetition number for new data transmission could also be used for UL, wherein step 820 for assisted report is needless.

In the embodiment in FIG. 8, UE could try early decoding before receiving the complete repetitions, and the possible number of used repetitions for early decoding is predefined, e.g. one third of repetitions and second thirds of repetitions. If the early decoding is successful, the information on actual number of used repetitions for early decoding is reported. In one example, the assisted information is explicitly reported by a physical signaling carried by PUCCH, e.g. one type of information including ACK/NACK and the number of actual used repetitions for successful decoding is reported. For example, 2bits information is reported by PUCCH, ‘00’ indicates ACK and one third of the first repetition number as the actual repetition number used for the successful decoding, ‘01’ indicates NACK and two thirds of the first repetition number as the actual repetition number used for the successful decoding, ‘10’ indicates NACK and the first repetition number as the actual repetition number used for the successful decoding, and ‘11’ indicates NACK. In one example, the assisted information is implied, e.g. an ACK could be immediately reported as long as early decoding is successful, and the actual number of used repetitions for early decoding could be implied by the occurrence of ACK report. And, additional PUCCH resource needs to be reserved for the potential ACK report for early decoding.

In the embodiment in FIG. 8, the transmission of the first transport block with the first repetition number may be first transmission or retransmission. In one example, the transmission is first transmission of the transport block, a relatively small repetition number may be used for next transport block with the same TBS, i.e. the second repetition number is smaller than the first repetition number, and the second repetition number is close to the reported actual number of used repetitions for early decoding. In another example, the transmission is retransmission of the transport block, the reported actual number of used repetitions for early decoding refers to the repetitions within the retransmission and doesn’t include previous repetitions of the transport block, even though the previous repetitions are used to combine with the retransmission for early decoding. Thus, a relatively large repetition number may be used for next transport block with the same TBS, i.e. the second repetition number is larger than the first repetition number, and the second repetition number is close to the sum of the reported actual number of used repetitions within the retransmission and the number of previous repetitions.

FIG. 9 shows an example of adaptive repetition number for DL retransmission. In one embodiment, receiving a repeated transmission of a transport block based on a first repetition number； reporting an information on an estimated repetition number for next retransmission of the transport block if the transport block is not successfully decoded； receiving a DCI associated with a retransmission of the transport block； determining a second repetition number based on a dedicated indicator in the DCI and it may be different from the first repetition number； receiving the repeated retransmission of the transport block based on the second repetition number.

In the embodiment in FIG. 9, repetition number is dynamically adjusted for retransmission based on the reported assisted information. The adjusted repetition number is determined based on a dedicated DCI field using the methods in FIG. 4, FIG. 5 or FIG. 6. And the transmission based on the first repetition number may be first transmission or retransmission. In one example, the second repetition number is different from the reported estimated repetition number considering eNB implementation. In one example, the second repetition number is the same to the first repetition number. The adaptive repetition number for retransmission could also be used for UL, wherein step 920 for assisted report is needless.

In the embodiment in FIG. 9, UE could estimate a required repetition number for retransmission based on a measurement result if the transport block is not successfully decoded, e.g. a combined SINR of all repetitions, wherein previous repetitions are included if the transmission is retransmission of a transport block. According to the gap between the combined SINR and the required SINR at 10％BLER, a required repetition number could be estimated and reported for next retransmission. In one example, the estimated repetition number jointly with ACK/NACK is reported by PUCCH, e.g., 2bits information, ‘00’ indicates ACK, ‘01’ indicates NACK and one third of the first repetition number as the required repetition number for next retransmission, ‘10’ indicates NACK and half of the first repetition number as the required repetition number for next retransmission, and ‘11’ indicates NACK and the first repetition number as the required repetition number for next retransmission. In one example, the UE may report one type of information of a combined SINR of all repetitions if a transport block is not successfully decoded. And eNB could adjust the repetition number for next retransmission based on the information of the combined SINR.

FIG. 10 shows an example of a compact DCI design with dynamic adjustment of repetition number just for retransmission of a transport block. In one embodiment, receiving a DCI associated with a physical data channel； determining whether the transmission is retransmission or not based on the value of new data indicator (NDI) field in the DCI； if the transmission is first transmission of a transport block, interpreting a DCI field as modulation and coding scheme (MCS) field, and determining the TBS based on the value of MCS field, and then determining the repetition number of the first transmission based on the TBS and a set of repetition numbers which is configured by a UE-specific high layer signaling for the physical data channel, wherein each one within the set of repetition numbers corresponds to a TBS； if the transmission is a retransmission of the transport block, interpreting the DCI field as RNO which is interpreted as MCS under first transmission, and then determining a repetition number of the retransmission based on the value of RNO field and the repetition number used by the first transmission of the transport block； transmitting or receiving the physical data channel based on the determined repetition number.

In the embodiment in FIG. 10, the repetition number of a first transmission is semi-statically configured by a UE-specific high layer signaling, e.g. using the methods in FIG. 2 or FIG. 3. However, the repetition number of a retransmission can be dynamically adjusted by a RNO field in a DCI, e.g. using the methods in FIG. 5 or FIG. 6. For DL repetition, some report of assisted information may be helpful to adjust repetition number for retransmission, e.g. using the methods in FIG. 9. And, the RNO field under retransmission reuses the MCS field under first transmission for a compact DCI design, i.e. interpreting the meaning of a DCI field depends on the value of NDI in the DCI. In one example, the RNO field under retransmission reuses other field which exists just under first transmission, e.g. resource block assignment (RBA) field. In the case, retransmission doesn’t support adaptive resource allocation, i.e. using the same resource allocation of first transmission or a predefined frequency hopping pattern based on the resource allocation of first transmission.

While the present disclosure and the best modes thereof have been described in a manner establishing possession and enabling those of ordinary skill to make and use the same, it will be understood and appreciated that there are equivalents to the exemplary embodiments disclosed herein and that modifications and variations may be made thereto without departing from the scope and spirit of the inventions, which are to be limited not by the exemplary embodiments but by the appended claims.

Those with skill in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those with skill in the art will further appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique) , various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as “software” or a “software module” ) , or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

In addition, the various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit ( “IC” ) , an access terminal, or an access point. The IC may comprise a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

It is understood that any specific order or hierarchy of steps in any disclosed process is an example of a sample approach. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module (e.g., including executable instructions and related data) and other data may reside in a data memory such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium known in the art. A sample storage medium may be coupled to a machine such as, for example, a computer/processor (which may be referred to herein, for convenience, as a “processor” ) such that the processor can read information (e.g., code) from and write information to the storage medium. A sample storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in user equipment. In the alternative, the processor and the storage medium may reside as discrete components in user equipment. Moreover, in some aspects any suitable computer-program product may comprise a computer-readable medium comprising codes relating to one or more of the aspects of the disclosure. In some aspects a computer program product may comprise packaging materials.

While the invention has been described in connection with various aspects, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains.

Claims

A method to determine a repetition number of a physical data channel for a user equipment (UE) , comprising:

determining a repetition number of a physical data channel based on a UE-specific high layer signaling and/or an indicator in downlink control information (DCI) ； and

transmitting or receiving the physical data channel based on the determined repetition number.
The method of claim 1, wherein determining a repetition number of a physical data channel based on a UE-specific high layer signaling further comprising:

configuring a set of repetition numbers by the UE-specific high layer signaling, wherein each one within the set of repetition numbers corresponds to a transport block size (TBS) of the physical data channel；

receiving a DCI associated with the physical data channel；

determining a TBS of the physical data channel based on the DCI； and

determining a repetition number of the physical data channel based on the set of repetition numbers and the TBS.
The method of claim 2, wherein the set of repetition numbers is determined based on an index of repetition level indicated by the UE-specific high layer signaling and a predefined table specifying a repetition number for each TBS and each repetition level.
The method of claim 2, wherein the index of repetition level indicated by the UE-specific high layer signaling is shared by other physical channel with the same transmission direction of the physical data channel.
The method of claim 4, wherein the predefined table also specifies a repetition number of other physical channel for each repetition level.
A method to dynamically adjust repetition number of PDSCH with a report of assisted information for a UE, comprising:

configuring a first repetition number for a transport block；

reporting an assisted information related to the decoding result of the transport block； and

configuring a second repetition number for another transport block or retransmission of the transport block, wherein the second repetition number is different from the first repetition number.
The method of claim 6, wherein the assisted information is the actual number of used repetitions for early decoding if the early decoding is successful.
The method of claim 6, wherein the assisted information is an estimated repetition number required for next retransmission by UE if the transport block is not successfully decoded.
The method of claim 8, wherein the required repetition number is estimated based on a combined SINR of all repetitions of the transport block.
The method of claim 6, wherein the assisted information is reported jointly with ACK/NACK by PUCCH.