Patent Description:
<NPL>, and <NPL>, disclose using a group common PDCCH to carry information of the slot structure. <CIT> discloses methods for reducing control channel resource usage in short Transmission Time Intervals (sTTIs) by configuring time section transmission resource structures via RRC signaling in wireless communication systems.

A method and apparatus are disclosed from the perspective of a UE (User Equipment) and a base station and apparatus are defined in the independent claims. The dependent claims define preferred embodiments thereof.

The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A or LTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra Mobile Broadband), WiMax, or some other modulation techniques.

In particular, the exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named "3rd Generation Partnership Project" referred to herein as <NPL>; <NPL>"; <NPL>"; <NPL>"; <NPL>"; RAN1# 86bis Chairman's note; and RAN1#<NUM> Chairman's note.

<FIG> shows a multiple access wireless communication system according to one embodiment of the invention. An access network <NUM> (AN) includes multiple antenna groups, one including <NUM> and <NUM>, another including <NUM> and <NUM>, and an additional including <NUM> and <NUM>. In <FIG>, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal <NUM> (AT) is in communication with antennas <NUM> and <NUM>, where antennas <NUM> and <NUM> transmit information to access terminal <NUM> over forward link <NUM> and receive information from access terminal <NUM> over reverse link <NUM>. Access terminal (AT) <NUM> is in communication with antennas <NUM> and <NUM>, where antennas <NUM> and <NUM> transmit information to access terminal (AT) <NUM> over forward link <NUM> and receive information from access terminal (AT) <NUM> over reverse link <NUM>. In a FDD system, communication links <NUM>, <NUM>, <NUM> and <NUM> may use different frequency for communication. For example, forward link <NUM> may use a different frequency then that used by reverse link <NUM>.

In communication over forward links <NUM> and <NUM>, the transmitting antennas of access network <NUM> may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals <NUM> and <NUM>. Also, an access network using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access network transmitting through a single antenna to all its access terminals.

An access network (AN) may be a fixed station or base station used for communicating with the terminals and may also be referred to as an access point, a Node B, a base station, an enhanced base station, an evolved Node B (eNB), or some other terminology. An access terminal (AT) may also be called user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.

<FIG> is a simplified block diagram of an embodiment of a transmitter system <NUM> (also known as the access network) and a receiver system <NUM> (also known as access terminal (AT) or user equipment (UE)) in a MIMO system <NUM>. At the transmitter system <NUM>, traffic data for a number of data streams is provided from a data source <NUM> to a transmit (TX) data processor <NUM>.

Preferably, each data stream is transmitted over a respective transmit antenna. TX data processor <NUM> formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by processor <NUM>.

At receiver system <NUM>, the transmitted modulated signals are received by NR antennas 252a through 252r and the received signal from each antenna <NUM> is provided to a respective receiver (RCVR) 254a through 254r. Each receiver <NUM> conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding "received" symbol stream.

Turning to <FIG>, this figure shows an alternative simplified functional block diagram of a communication device according to one embodiment of the invention. As shown in <FIG>, the communication device <NUM> in a wireless communication system can be utilized for realizing the UEs (or ATs) <NUM> and <NUM> in <FIG> or the base station (or AN) <NUM> in <FIG>, and the wireless communications system is preferably the LTE system. The communication device <NUM> may include an input device <NUM>, an output device <NUM>, a control circuit <NUM>, a central processing unit (CPU) <NUM>, a memory <NUM>, a program code <NUM>, and a transceiver <NUM>. The control circuit <NUM> executes the program code <NUM> in the memory <NUM> through the CPU <NUM>, thereby controlling an operation of the communications device <NUM>. The communications device <NUM> can receive signals input by a user through the input device <NUM>, such as a keyboard or keypad, and can output images and sounds through the output device <NUM>, such as a monitor or speakers. The transceiver <NUM> is used to receive and transmit wireless signals, delivering received signals to the control circuit <NUM>, and outputting signals generated by the control circuit <NUM> wirelessly. The communication device <NUM> in a wireless communication system can also be utilized for realizing the AN <NUM> in <FIG>.

<FIG> is a simplified block diagram of the program code <NUM> shown in <FIG> in accordance with one embodiment of the invention. In this embodiment, the program code <NUM> includes an application layer <NUM>, a Layer <NUM> portion <NUM>, and a Layer <NUM> portion <NUM>, and is coupled to a Layer <NUM> portion <NUM>. The Layer <NUM> portion <NUM> generally performs radio resource control. The Layer <NUM> portion <NUM> generally performs link control. The Layer <NUM> portion <NUM> generally performs physical connections.

Packet data latency is generally one of the important metrics for performance evaluation. Reducing packet data latency improves the system performance. In 3GPP RP-<NUM>, the study item "study on latency reduction techniques for LTE" aims to investigate and standardize some techniques of latency reduction.

According to 3GPP RP-<NUM>, the objective of the study item is to study enhancements to the E-UTRAN (Evolved Universal Terrestrial Radio Access Network) radio system in order to significantly reduce the packet data latency over the LTE Uu air interface for an active UE and significantly reduce the packet data transport round trip latency for UEs that have been inactive for a longer period (in connected state). The study area includes resource efficiency, including air interface capacity, battery lifetime, control channel resources, specification impact and technical feasibility. Both FDD (Frequency Division Duplex) and TDD (Time Division Duplex) duplex modes are considered.

According to 3GPP RP-<NUM>, two areas should be studied and documented as follows:.

For active UEs and UEs that have been inactive a longer time, but are kept in RRC Connected, focus should be on reducing user plane latency for the scheduled UL transmission and on getting a more resource efficient solution with protocol and signaling enhancements, compared to the pre-scheduling solutions allowed by the standard today, both with and without preserving the current TTI length and processing times.

Assess specification impact and study feasibility and performance of TTI lengths between <NUM> and one OFDM symbol, taking into account impact on reference signals and physical layer control signaling.

TTI shortening and processing time reduction can be considered as an effective solution for reducing latency, as the time unit for transmission can be reduced (e.g., from1ms (<NUM> OFDM) symbol to <NUM>~<NUM> OFDM symbols), and the delay caused by decoding can be reduced as well. Another benefit of shortening TTI length is to support a finer granularity of transport block (TB) size, so that unnecessary padding could be reduced. On the other hand, reducing the length of TTI may also have significant impact to current system design as the physical channels are developed based on <NUM> structure. A shortened TTI is also called an sTTI.

Frame structure used in New RAT (NR) for <NUM>, to accommodate various type of requirement (as discussed in 3GPP RP-<NUM>) for time and frequency resource, e.g. from ultra-low latency (~<NUM>) to delay-tolerant traffic for MTC (Machine Type Communication), from high peak rate for eMBB (Enhanced Mobile Broadband) to very low data rate for MTC. An important focus of this study is low latency aspect, e.g., short TTI, while other aspect of mixing or adapting different TTIs can also be considered in the study. In addition to diverse services and requirements, forward compatibility is an important consideration in initial NR frame structure design as not all features of NR would be included in the beginning phase or release.

Reducing latency of protocol is an important improvement between different generations or releases, which can improve efficiency as well as meeting new application requirements, e.g., real-time service. An effective method frequently adopted to reduce latency is to reduce the length of TTIs, from <NUM> in <NUM> to <NUM> in LTE. In the context of LTE-A Pro in REl-<NUM>, SI or WI was proposed to reduce the TTI to sub-ms level, e.g. <NUM>~<NUM>, by reducing the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols within a TTI, without changing any existing LTE numerology, i.e., in LTE there is only one numerology. The target of this improvement can be to solve the TCP (Transport Control Protocol) slow start issue, extremely low but frequent traffic, or to meet foreseen ultra-low latency in NR to some extent. Processing time reduction is another consideration to reduce the latency. It has not yet concluded that whether short TTI and short processing time always come together. The study suffers from some limitation, as the method adopted should preserve backward compatibility, e.g., the existence of legacy control region. A brief description of LTE numerology is given below (as discussed in 3GPP TR <NUM>):.

The smallest time-frequency unit for downlink transmission is denoted a resource element and is defined in clause <NUM>.

A subset of the downlink subframes in a radio frame on a carrier supporting PDSCH transmission can be configured as MBSFN subframes by higher layers. Each MBSFN subframe is divided into a non-MBSFN region and an MBSFN region.

For frame structure type <NUM>, MBSFN configuration shall not be applied to downlink subframes in which at least one OFDM symbol is not occupied or discovery signal is transmitted.

Unless otherwise specified, transmission in each downlink subframe shall use the same cyclic prefix length as used for downlink subframe #<NUM>.

A downlink physical channel corresponds to a set of resource elements carrying information originating from higher layers and is the interface defined between 3GPP TS <NUM> [<NUM>] and the present document 3GPP TS <NUM>.

The following downlink physical channels are defined:.

A downlink physical signal corresponds to a set of resource elements used by the physical layer but does not carry information originating from higher layers. The following downlink physical signals are defined:.

The transmitted signal in each slot is described by one or several resource grids of <MAT> subcarriers and <MAT> OFDM symbols. The resource grid structure is illustrated in Figure <NUM>. <NUM>-<NUM>. The quantity <MAT> depends on the downlink transmission bandwidth configured in the cell and shall fulfil <MAT> where <MAT> and <MAT> are the smallest and largest downlink bandwidths, respectively, supported by the current version of this specification.

The set of allowed values for <MAT> is given by 3GPP TS <NUM> [<NUM>]. The number of OFDM symbols in a slot depends on the cyclic prefix length and subcarrier spacing configured and is given in Table <NUM>. <NUM>-<NUM>.

An antenna port is defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed. For MBSFN reference signals, positioning reference signals, UE-specific reference signals associated with PDSCH and demodulation reference signals associated with EPDCCH, there are limits given below within which the channel can be inferred from one symbol to another symbol on the same antenna port. There is one resource grid per antenna port. The set of antenna ports supported depends on the reference signal configuration in the cell:.

Two antenna ports are said to be quasi co-located if the large-scale properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed. The large-scale properties include one or more of delay spread, Doppler spread, Doppler shift, average gain, and average delay.

Each element in the resource grid for antenna port p is called a resource element and is uniquely identified by the index pair (k,l) in a slot where <MAT> and <MAT> are the indices in the frequency and time domains, respectively. Resource element (k,l) on antenna port p corresponds to the complex value <MAT>.

When there is no risk for confusion, or no particular antenna port is specified, the index p may be dropped.

Resource blocks are used to describe the mapping of certain physical channels to resource elements. Physical and virtual resource blocks are defined.

A physical resource block is defined as <MAT> consecutive OFDM symbols in the time domain and <MAT> consecutive subcarriers in the frequency domain, where <MAT> and <MAT> are given by Table <NUM>. <NUM>-<NUM>. A physical resource block thus consists of <MAT> resource elements, corresponding to one slot in the time domain and <NUM> in the frequency domain.

Physical resource blocks are numbered from <NUM> to <MAT> in the frequency domain. The relation between the physical resource block number nPRB in the frequency domain and resource elements (k,l) in a slot is given by <MAT>.

A physical resource-block pair is defined as the two physical resource blocks in one subframe having the same physical resource-block number nPRB.

A virtual resource block is of the same size as a physical resource block. Two types of virtual resource blocks are defined:.

For each type of virtual resource blocks, a pair of virtual resource blocks over two slots in a subframe is assigned together by a single virtual resource block number, nVRB.

The physical control format indicator channel carries information about the number of OFDM symbols used for transmission of PDCCHs in a subframe. The set of OFDM symbols possible to use for PDCCH in a subframe is given by Table <NUM>-<NUM>.

The UE may assume the PCFICH is transmitted when the number of OFDM symbols for PDCCH is greater than zero unless stated otherwise in [<NUM>, clause <NUM>].

The block of bits b(<NUM>),. ,b(<NUM>) transmitted in one subframe shall be scrambled with a cell-specific sequence prior to modulation, resulting in a block of scrambled bits b̃(<NUM>),. ,b̃(<NUM>) according to <MAT> where the scrambling sequence c(i) is given by clause <NUM>. The scrambling sequence generator shall be initialised with <MAT> at the start of each subframe.

The block of scrambled bits b̃(<NUM>),. ,b̃(<NUM>) shall be modulated as described in clause <NUM>, resulting in a block of complex-valued modulation symbols d(<NUM>),. Table <NUM>. <NUM>-<NUM> specifies the modulation mappings applicable for the physical control format indicator channel.

The block of modulation symbols d(<NUM>),. ,d(<NUM>) shall be mapped to layers according to one of clauses <NUM>. <NUM> or <NUM>. <NUM> with <MAT> and precoded according to one of clauses <NUM>. <NUM> or <NUM>. <NUM>, resulting in a block of vectors y(i) = [y(<NUM>)(i). y(P-<NUM>)(i)]T , i = <NUM>,. ,<NUM>, where y(p)(i) represents the signal for antenna port p and where p = <NUM>,. ,P- 1and the number of antenna ports for cell-specific reference signals P ∈{<NUM>,<NUM>,<NUM>}. The PCFICH shall be transmitted on the same set of antenna ports as the PBCH.

The mapping to resource elements is defined in terms of quadruplets of complex-valued symbols. Let z(p)(i) = 〈y(p)(<NUM>i), y(p)(<NUM>i + <NUM>), y(p)(<NUM>i + <NUM>), y(p) (<NUM>i + <NUM>)〉 denote symbol quadruplet i for antenna port p. For each of the antenna ports, symbol quadruplets shall be mapped in increasing order of i to the four resource-element groups in the first OFDM symbol in a downlink subframe or DwPTS with the representative resource-element as defined in clause <NUM>. <NUM> given by.

where the additions are modulo <MAT>, <MAT> and <MAT> is the physical-layer cell identity as given by clause <NUM>.

The physical downlink control channel carries scheduling assignments and other control information. A physical control channel is transmitted on an aggregation of one or several consecutive control channel elements (CCEs), where a control channel element corresponds to <NUM> resource element groups. The number of resource-element groups not assigned to PCFICH or PHICH is NREG. The CCEs available in the system are numbered from <NUM> to NCCE - <NUM>, where <MAT>. The PDCCH supports multiple formats as listed in Table <NUM>. <NUM>-<NUM>. A PDCCH consisting of n consecutive CCEs may only start on a CCE fulfilling i mod n = <NUM>, where i is the CCE number.

Multiple PDCCHs can be transmitted in a subframe.

The block of bits <MAT> on each of the control channels to be transmitted in a subframe, where <MAT> is the number of bits in one subframe to be transmitted on physical downlink control channel number i, shall be multiplexed, resulting in a block of bits <MAT>, where nPDCCH is the number of PDCCHs transmitted in the subframe.

The block of bits <MAT> shall be scrambled with a cell-specific sequence prior to modulation, resulting in a block of scrambled bits b̃(<NUM>),. ,b̃(Mtot -<NUM>) according to <MAT> where the scrambling sequence c(i) is given by clause <NUM>. The scrambling sequence generator shall be initialised with <MAT> at the start of each subframe.

CCE number n corresponds to bits b(<NUM>n),b(<NUM>n +<NUM>),. ,b(<NUM>n +<NUM>). If necessary, <NIL> elements shall be inserted in the block of bits prior to scrambling to ensure that the PDCCHs starts at the CCE positions as described in 3GPP TS <NUM> [<NUM>] and to ensure that the length <MAT> of the scrambled block of bits matches the amount of resource-element groups not assigned to PCFICH or PHICH.

The block of scrambled bits b̃(<NUM>),. ,b̃(Mtot -<NUM>) shall be modulated as described in clause <NUM>, resulting in a block of complex-valued modulation symbols d(<NUM>),. ,d(Msymb -<NUM>). Table <NUM>. <NUM>-<NUM> specifies the modulation mappings applicable for the physical downlink control channel.

The block of modulation symbols d(<NUM>),. ,d(Msymb -<NUM>) shall be mapped to layers according to one of clauses <NUM>. <NUM> or <NUM>. <NUM> with <MAT> and precoded according to one of clauses <NUM>. <NUM> or <NUM>. <NUM>, resulting in a block of vectors y(i) = [y(<NUM>)(i). y(P-<NUM>)(i)]T , i = <NUM>,. , Msymb -<NUM> to be mapped onto resources on the antenna ports used for transmission, where y(p)(i) represents the signal for antenna port p. The PDCCH shall be transmitted on the same set of antenna ports as the PBCH.

The mapping to resource elements is defined by operations on quadruplets of complex-valued symbols. Let z(p)(i) = 〈y(p)(<NUM>i), y(p)(<NUM>i + <NUM>), y(p)(<NUM>i + <NUM>), y(p)(<NUM>i + <NUM>)〉 denote symbol quadruplet i for antenna portp.

The block of quadruplets z(p)(<NUM>),. , z(p)(Mquad -<NUM>), where Mquad = Msymb/<NUM>, shall be permuted resulting in w(p)(<NUM>),. , w(p)(Mquad -<NUM>). The permutation shall be according to the sub-block interleaver in clause <NUM>. <NUM> of 3GPP TS <NUM> [<NUM>] with the following exceptions:.

<NULL> elements at the output of the interleaver in 3GPP TS <NUM> [<NUM>] shall be removed when forming w(p)(<NUM>),. ,w(p)(Mquad -<NUM>). Note that the removal of <NULL> elements does not affect any <NIL> elements inserted in clause <NUM>.

The block of quadruplets w(p)(<NUM>),. ,w(p)(Mquad -<NUM>) shall be cyclically shifted, resulting in w(p)(<NUM>),. ,w(p)(Mquad -<NUM>) where <MAT>.

Mapping of the block of quadruplets w(p)(<NUM>),. ,w(p)(Mquad -<NUM>) is defined in terms of resource-element groups, specified in clause <NUM>. <NUM>, according to steps <NUM>-<NUM> below:.

The time-continuous signal <MAT> on antenna port p in OFDM symbol l in a downlink slot is defined by <MAT> for <NUM> ≤ t < (NCP,l + N)×Ts where <MAT> and <MAT>. The variable N equals <NUM> for Δf = <NUM> subcarrier spacing and <NUM> for Δf = <NUM> subcarrier spacing.

The OFDM symbols in a slot shall be transmitted in increasing order of l, starting with l = <NUM>, where OFDM symbol l > <NUM> starts at time <MAT> within the slot. In case the first OFDM symbol(s) in a slot use normal cyclic prefix and the remaining OFDM symbols use extended cyclic prefix, the starting position the OFDM symbols with extended cyclic prefix shall be identical to those in a slot where all OFDM symbols use extended cyclic prefix. Thus there will be a part of the time slot between the two cyclic prefix regions where the transmitted signal is not specified.

Table <NUM>-<NUM> lists the value of NCP,l that shall be used. Note that different OFDM symbols within a slot in some cases have different cyclic prefix lengths.

Modulation and upconversion to the carrier frequency of the complex-valued OFDM baseband signal for each antenna port is shown in Figure <NUM>-<NUM>. The filtering required prior to transmission is defined by the requirements in 3GPP TS <NUM> [<NUM>].

In LTE, there is only one DL (Downlink) numerology defined for initial access, which is <NUM> subcarrier spacing and the signal and channel to be acquired during initial access is based on <NUM> numerology. To access a cell, UE may need to acquire some fundamental information. For example, UE first acquires time or frequency synchronization of cell, which is done during cell search or cell selection or reselection. The time or frequency synchronization can be obtained by receiving synchronization signal, such as primary synchronization signal (PSS) or secondary synchronization signal (SSS). During synchronization, the center frequency of a cell is known, and the subframe or frame boundary is obtained. Cyclic prefix (CP) of the cell, e.g., normal CP or extended CP, duplex mode of the cell, e.g., FDD or TDD can be known as well when PSS/SSS are acquired. And then, a master information block (MIB) carried on physical broadcast channel (PBCH) is received, some fundamental system information, e.g., system frame number (SFN), system bandwidth, physical control channel related information. The UE would receive the DL control channel (e.g., PDCCH (Physical Downlink Control Channel) on proper resource elements and with proper payload size according to the system bandwidth and can acquire some more system information required to access the cell in system information block (SIB), such as whether the cell can be access, UL bandwidth and frequency, random access parameter, and so on. The UE then can perform random access and request the connection to the cell. After the connection set up is complete, the UE would enter connected mode and be able to perform data transmission to the cell or perform data reception from the cell. The resource allocation for data reception and transmission is done according to system bandwidth (e.g., <MAT> or <MAT> in the following quotation) signaled in MIB or SIB. More details can be found in 3GPP TR <NUM>, TS <NUM>, TS <NUM>, and TS <NUM> as follows:.

A DCI transports downlink, uplink or sidelink scheduling information, requests for aperiodic CQI reports, LAA common information, notifications of MCCH change [<NUM>] or uplink power control commands for one cell and one RNTI. The RNTI is implicitly encoded in the CRC.

Figure <NUM>. <NUM>-<NUM> shows the processing structure for one DCI. The following coding steps can be identified:.

The coding steps for DCI are shown in the figure below.

The fields defined in the DCI formats below are mapped to the information bits a<NUM> to aA-<NUM> as follows.

Each field is mapped in the order in which it appears in the description, including the zero-padding bit(s), if any, with the first field mapped to the lowest order information bit a<NUM> and each successive field mapped to higher order information bits. The most significant bit of each field is mapped to the lowest order information bit for that field, e.g. the most significant bit of the first field is mapped to a<NUM>.

DCI format <NUM> is used for the scheduling of PUSCH in one UL cell.

The following information is transmitted by means of the DCI format <NUM>:.

If the number of information bits in format <NUM> mapped onto a given search space is less than the payload size of format 1A for scheduling the same serving cell and mapped onto the same search space (including any padding bits appended to format 1A), zeros shall be appended to format <NUM> until the payload size equals that of format 1A.

If the UE is configured with a SCG, the UE shall apply the procedures described in this clause for both MCG and SCG.

For a non-BL/CE UE, and for FDD and transmission mode <NUM>, there shall be <NUM> uplink HARQ processes per serving cell for non-subframe bundling operation, i.e. normal HARQ operation, and <NUM> uplink HARQ processes for subframe bundling operation when parameter e-HARQ-Pattern-r12 is set to TRUE and <NUM> uplink HARQ processes for subframe bundling operation otherwise. For a non-BL/CE UE, and for FDD and transmission mode <NUM>, there shall be <NUM> uplink HARQ processes per serving cell for non-subframe bundling operation and there are two HARQ processes associated with a given subframe as described in [<NUM>]. The subframe bundling operation is configured by the parameter ttiBundling provided by higher layers.

For FDD and a BL/CE UE configured with CEModeA, there shall be at most <NUM> uplink HARQ processes per serving cell.

For FDD and a BL/CE UE configured with CEModeB, there shall be at most <NUM> uplink HARQ processes per serving cell.

In case higher layers configure the use of subframe bundling for FDD and TDD, the subframe bundling operation is only applied to UL-SCH, such that four consecutive uplink subframes are used.

A BL/CE UE is not expected to be configured with simultaneous PUSCH and PUCCH transmission.

The term "UL/DL configuration" in this subclause refers to the higher layer parameter subframeAssignment unless specified otherwise.

For FDD and normal HARQ operation, the UE shall upon detection on a given serving cell of a PDCCH/EPDCCH with DCI format <NUM>/<NUM> and/or a PHICH transmission in subframe n intended for the UE, adjust the corresponding PUSCH transmission in subframe n+<NUM> according to the PDCCH/EPDCCH and PHICH information.

For FDD-TDD and normal HARQ operation and a PUSCH for serving cell c with frame structure type <NUM>, the UE shall upon detection of a PDCCH/EPDCCH with DCI format <NUM>/<NUM> and/or a PHICH transmission in subframe n intended for the UE, adjust the corresponding PUSCH transmission for serving cell c in subframe n+<NUM> according to the PDCCH/EPDCCH and PHICH information.

For normal HARQ operation, if the UE detects a PHICH transmission and if the most recent PUSCH transmission for the same transport block was using spatial multiplexing according to subclause <NUM>. <NUM> and the UE does not detect a PDCCH/EPDCCH with DCI format <NUM> in subframe n intended for the UE, the UE shall adjust the corresponding PUSCH retransmission in the associated subframe according to the PHICH information, and using the number of transmission layers and precoding matrix according to the most recent PDCCH/EPDCCH, if the number of negatively acknowledged transport blocks is equal to the number of transport blocks indicated in the most recent PDCCH/EPDCCH associated with the corresponding PUSCH.

For normal HARQ operation, if the UE detects a PHICH transmission and if the most recent PUSCH transmission for the same transport block was using spatial multiplexing according to subclause <NUM>. <NUM> and the UE does not detect a PDCCH/EPDCCH with DCI format <NUM> in subframe n intended for the UE, and if the number of negatively acknowledged transport blocks is not equal to the number of transport blocks indicated in the most recent PDCCH/EPDCCH associated with the corresponding PUSCH then the UE shall adjust the corresponding PUSCH retransmission in the associated subframe according to the PHICH information, using the precoding matrix with codebook index <NUM> and the number of transmission layers equal to number of layers corresponding to the negatively acknowledged transport block from the most recent PDCCH/EPDCCH. In this case, the UL DMRS resources are calculated according to the cyclic shift field for DMRS [<NUM>] in the most recent PDCCH/EPDCCH with DCI format <NUM> associated with the corresponding PUSCH transmission and number of layers corresponding to the negatively acknowledged transport block.

If a UE is configured with the carrier indicator field for a given serving cell, the UE shall use the carrier indicator field value from the detected PDCCH/EPDCCH with uplink DCI format to determine the serving cell for the corresponding PUSCH transmission.

For FDD and normal HARQ operation, if a PDCCH/EPDCCH with CSI request field set to trigger an aperiodic CSI report, as described in subclause <NUM>. <NUM>, is detected by a UE on subframe n, then on subframe n+<NUM> UCI is mapped on the corresponding PUSCH transmission, when simultaneous PUSCH and PUCCH transmission is not configured for the UE.

When a UE is configured with higher layer parameter ttiBundling and configured with higher layer parameter e-HARQ-Pattern-r12 set to FALSE or not configured, for FDD and subframe bundling operation, the UE shall upon detection of a PDCCH/EPDCCH with DCI format <NUM> in subframe n intended for the UE, and/or a PHICH transmission in subframe n-<NUM> intended for the UE, adjust the corresponding first PUSCH transmission in the bundle in subframe n+<NUM> according to the PDCCH/EPDCCH and PHICH information.

When a UE is configured with higher layer parameter ttiBundling and configured with higher layer parameter e-HARQ-Pattern-r12 set to TRUE, for FDD and subframe bundling operation, the UE shall upon detection of a PDCCH/EPDCCH with DCI format <NUM> in subframe n intended for the UE, and/or a PHICH transmission in subframe n-<NUM> intended for the UE, adjust the corresponding first PUSCH transmission in the bundle in subframe n+<NUM> according to the PDCCH/EPDCCH and PHICH information.

For both FDD and TDD serving cells, the NDI as signalled on PDCCH/EPDCCH, the RV as determined in subclause <NUM>. <NUM>, and the TBS as determined in subclause <NUM>. <NUM>, shall be delivered to higher layers.

For a non-BL/CE UE, for TDD and transmission mode <NUM>, the number of HARQ processes per serving cell shall be determined by the UL/DL configuration (Table <NUM>-<NUM> of [<NUM>]), as indicated in Table <NUM>-<NUM>. For TDD and transmission mode <NUM>, the number of HARQ processes per serving cell for non-subframe bundling operation shall be twice the number determined by the UL/DL configuration (Table <NUM>-<NUM> of [<NUM>]) as indicated in Table <NUM>-<NUM> and there are two HARQ processes associated with a given subframe as described in [<NUM>]. For TDD and both transmission mode <NUM> and transmission mode <NUM>, the "TDD UL/DL configuration" in Table <NUM>-<NUM> refers to the UL-reference UL/DL configuration for the serving cell if UL-reference UL/DL configuration is defined for the serving cell and refers to the serving cell UL/DL configuration otherwise.

For a BL/CE UE configured with CEModeA and for TDD, the maximum number of HARQ processes per serving cell shall be determined by the UL/DL configuration (Table <NUM>-<NUM> of [<NUM>]) according to the normal HARQ operation in Table <NUM>-<NUM>. For TDD a BL/CE UE configured with CEModeB is not expected to support more than <NUM> uplink HARQ processes per serving cell.

A UE is semi-statically configured via higher layer signalling to transmit PUSCH transmissions signalled via PDCCH/EPDCCH according to one of two uplink transmission modes, denoted mode <NUM> - <NUM>.

If a UE is configured by higher layers to decode PDCCHs with the CRC scrambled by the C-RNTI, the UE shall decode the PDCCH according to the combination defined in Table <NUM>-<NUM> and transmit the corresponding PUSCH. The scrambling initialization of this PUSCH corresponding to these PDCCHs and the PUSCH retransmission for the same transport block is by C-RNTI.

If a UE is configured by higher layers to decode EPDCCHs with the CRC scrambled by the C-RNTI, the UE shall decode the EPDCCH according to the combination defined in Table <NUM>-3A and transmit the corresponding PUSCH. The scrambling initialization of this PUSCH corresponding to these EPDCCHs and the PUSCH retransmission for the same transport block is by C-RNTI.

If a UE is configured by higher layers to decode MPDCCHs with the CRC scrambled by the C-RNTI, the UE shall decode the MPDCCH according to the combination defined in Table <NUM>-3B and transmit the corresponding PUSCH. The scrambling initialization of this PUSCH corresponding to these MPDCCHs and the PUSCH retransmission for the same transport block is by C-RNTI.

Transmission mode <NUM> is the default uplink transmission mode for a UE until the UE is assigned an uplink transmission mode by higher layer signalling.

When a UE configured in transmission mode <NUM> receives a DCI Format <NUM> uplink scheduling grant, it shall assume that the PUSCH transmission is associated with transport block <NUM> and that transport block <NUM> is disabled.

If a UE is configured by higher layers to decode PDCCHs with the CRC scrambled by the C-RNTI and is also configured to receive random access procedures initiated by "PDCCH orders", the UE shall decode the PDCCH according to the combination defined in Table <NUM>-<NUM>.

If a UE is configured by higher layers to decode EPDCCHs with the CRC scrambled by the C-RNTI and is also configured to receive random access procedures initiated by "PDCCH orders", the UE shall decode the EPDCCH according to the combination defined in Table <NUM>-4A.

If a UE is configured by higher layers to decode MPDCCHs with the CRC scrambled by the C-RNTI and is also configured to receive random access procedures initiated by "PDCCH orders", the UE shall decode the MPDCCH according to the combination defined in Table <NUM>-4B.

If a UE is configured by higher layers to decode PDCCHs with the CRC scrambled by the SPS C-RNTI, the UE shall decode the PDCCH according to the combination defined in Table <NUM>-<NUM> and transmit the corresponding PUSCH.

The scrambling initialization of this PUSCH corresponding to these PDCCHs and PUSCH retransmission for the same transport block is by SPS C-RNTI. The scrambling initialization of initial transmission of this PUSCH without a corresponding PDCCH and the PUSCH retransmission for the same transport block is by SPS C-RNTI.

If a UE is configured by higher layers to decode EPDCCHs with the CRC scrambled by the SPS C-RNTI, the UE shall decode the EPDCCH according to the combination defined in Table <NUM>-5A and transmit the corresponding PUSCH.

The scrambling initialization of this PUSCH corresponding to these EPDCCHs and PUSCH retransmission for the same transport block is by SPS C-RNTI. The scrambling initialization of initial transmission of this PUSCH without a corresponding EPDCCH and the PUSCH retransmission for the same transport block is by SPS C-RNTI.

If a UE is configured by higher layers to decode MPDCCHs with the CRC scrambled by the SPS C-RNTI, the UE shall decode the MPDCCH according to the combination defined in Table <NUM>-5B and transmit the corresponding PUSCH.

The scrambling initialization of this PUSCH corresponding to these MPDCCHs and PUSCH retransmission for the same transport block is by SPS C-RNTI. The scrambling initialization of initial transmission of this PUSCH without a corresponding MPDCCH and the PUSCH retransmission for the same transport block is by SPS C-RNTI.

If a UE is configured by higher layers to decode PDCCHs with the CRC scrambled by the Temporary C-RNTI regardless of whether UE is configured or not configured to decode PDCCHs with the CRC scrambled by the C-RNTI, the UE shall decode the PDCCH according to the combination defined in Table <NUM>-<NUM> and transmit the corresponding PUSCH. The scrambling initialization of PUSCH corresponding to these PDCCH is by Temporary C-RNTI.

Two resource allocation schemes Type <NUM> and Type <NUM> are supported for PDCCH/EPDCCH with uplink DCI format.

Resource allocation scheme Type <NUM> or Type <NUM> are supported for MPDCCH with uplink DCI format.

If the resource allocation type bit is not present in the uplink DCI format, only resource allocation type <NUM> is supported.

If the resource allocation type bit is present in the uplink DCI format, the selected resource allocation type for a decoded PDCCH/EPDCCH is indicated by a resource allocation type bit where type <NUM> is indicated by <NUM> value and type <NUM> is indicated otherwise. The UE shall interpret the resource allocation field depending on the resource allocation type bit in the PDCCH/EPDCCH with uplink DCI format detected.

The resource allocation information for uplink resource allocation type <NUM> indicates to a scheduled UE a set of contiguously allocated virtual resource block indices denoted by nVRB. A resource allocation field in the scheduling grant consists of a resource indication value (RIV) corresponding to a starting resource block ( RBSTART ) and a length in terms of contiguously allocated resource blocks ( LCRBs ≥ <NUM>). For a BL/CE UE, uplink resource allocation type <NUM> is only applicable for UE configured with CEModeA and <MAT> in this subclause. The resource indication value is defined by
<IMG>.

The resource allocation information for uplink resource allocation type <NUM> indicates to a scheduled UE two sets of resource blocks with each set including one or more consecutive resource block groups of size P as given in table <NUM>. <NUM>-<NUM> assuming <MAT> as the system bandwidth. A combinatorial index r consists of <MAT> bits. The bits from the resource allocation field in the scheduling grant represent r unless the number of bits in the resource allocation field in the scheduling grant is.

The combinatorial index r corresponds to a starting and ending RBG index of resource block set <NUM>, s<NUM> and s<NUM> -<NUM>, and resource block set <NUM>, s<NUM> and s<NUM> -<NUM> respectively, where r is given by equation <MAT> defined in subclause <NUM>. <NUM> with M=<NUM> and <MAT>. subclause <NUM>. <NUM> also defines ordering properties and range of values that si (RBG indices) map to. Only a single RBG is allocated for a set at the starting RBG index if the corresponding ending RBG index equals the starting RBG index.

Uplink resource allocation type <NUM> is only applicable for BL/CE UE configured with CEModeB. The resource allocation information for uplink resource allocation type <NUM> indicates to a scheduled UE a set of contiguously allocated resource blocks within a narrowband as given in Table <NUM>. <NUM>-<NUM>.

The control region of each serving cell consists of a set of CCEs, numbered from <NUM> to NCCE,k -<NUM> according to subclause <NUM>. <NUM> in [<NUM>], where NCCE,k is the total number of CCEs in the control region of subframe k.

The UE shall monitor a set of PDCCH candidates on one or more activated serving cells as configured by higher layer signalling for control information, where monitoring implies attempting to decode each of the PDCCHs in the set according to all the monitored DCI formats.

A BL/CE UE is not required to monitor PDCCH.

The set of PDCCH candidates to monitor are defined in terms of search spaces, where a search space <MAT> at aggregation level L ∈ {<NUM>,<NUM>,<NUM>,<NUM>} is defined by a set of PDCCH candidates. For each serving cell on which PDCCH is monitored, the CCEs corresponding to PDCCH candidate m of the search space <MAT> are given by <MAT> where Yk is defined below, i = <NUM>,···,L-<NUM>. For the common search space m' = m. For the PDCCH UE specific search space, for the serving cell on which PDCCH is monitored, if the monitoring UE is configured with carrier indicator field then m' = m + M(L) · nCI where nCI is the carrier indicator field value, else if the monitoring UE is not configured with carrier indicator field then m' = m, where m =<NUM>,···,M(L) -<NUM>. M(L) is the number of PDCCH candidates to monitor in the given search space.

If a UE is configured with higher layer parameter cif-InSchedulingCell-r13, the carrier indicator field value corresponds to cif-InSchedulingCell-r13, otherwise, the carrier indicator field value is the same as ServCellIndex given in [<NUM>].

The UE shall monitor one common search space in every non-DRX subframe at each of the aggregation levels <NUM> and <NUM> on the primary cell.

A UE shall monitor common search space on a cell to decode the PDCCHs necessary to receive MBMS on that cell when configured by higher layers.

If a UE is not configured for EPDCCH monitoring, and if the UE is not configured with a carrier indicator field, then the UE shall monitor one PDCCH UE-specific search space at each of the aggregation levels <NUM>, <NUM>, <NUM>, <NUM> on each activated serving cell in every non-DRX subframe.

If a UE is not configured for EPDCCH monitoring, and if the UE is configured with a carrier indicator field, then the UE shall monitor one or more UE-specific search spaces at each of the aggregation levels <NUM>, <NUM>, <NUM>, <NUM> on one or more activated serving cells as configured by higher layer signalling in every non-DRX subframe.

If a UE is configured for EPDCCH monitoring on a serving cell, and if that serving cell is activated, and if the UE is not configured with a carrier indicator field, then the UE shall monitor one PDCCH UE-specific search space at each of the aggregation levels <NUM>, <NUM>, <NUM>, <NUM> on that serving cell in all non-DRX subframes where EPDCCH is not monitored on that serving cell.

If a UE is configured for EPDCCH monitoring on a serving cell, and if that serving cell is activated, and if the UE is configured with a carrier indicator field, then the UE shall monitor one or more PDCCH UE-specific search spaces at each of the aggregation levels <NUM>, <NUM>, <NUM>, <NUM> on that serving cell as configured by higher layer signalling in all non-DRX subframes where EPDCCH is not monitored on that serving cell.

The common and PDCCH UE-specific search spaces on the primary cell may overlap.

A UE configured with the carrier indicator field associated with monitoring PDCCH on serving cell c shall monitor PDCCH configured with carrier indicator field and with CRC scrambled by C-RNTI in the PDCCH UE specific search space of serving cell c.

A UE configured with the carrier indicator field associated with monitoring PDCCH on the primary cell shall monitor PDCCH configured with carrier indicator field and with CRC scrambled by SPS C-RNTI in the PDCCH UE specific search space of the primary cell.

The UE shall monitor the common search space for PDCCH without carrier indicator field.

For the serving cell on which PDCCH is monitored, if the UE is not configured with a carrier indicator field, it shall monitor the PDCCH UE specific search space for PDCCH without carrier indicator field, if the UE is configured with a carrier indicator field it shall monitor the PDCCH UE specific search space for PDCCH with carrier indicator field.

If the UE is not configured with a LAA Scell, the UE is not expected to monitor the PDCCH of a secondary cell if it is configured to monitor PDCCH with carrier indicator field corresponding to that secondary cell in another serving cell.

If the UE is configured with a LAA Scell, the UE is not expected to monitor the PDCCH UE specific space of the LAA SCell if it is configured to monitor PDCCH with carrier indicator field corresponding to that LAA Scell in another serving cell,.

For the serving cell on which PDCCH is monitored, the UE shall monitor PDCCH candidates at least for the same serving cell.

A UE configured to monitor PDCCH candidates with CRC scrambled by C-RNTI or SPS C-RNTI with a common payload size and with the same first CCE index nCCE (as described in subclause <NUM>) but with different sets of DCI information fields as defined in [<NUM>] in the.

A UE configured to monitor PDCCH candidates in a given serving cell with a given DCI format size with CIF, and CRC scrambled by C- RNTI, where the PDCCH candidates may have one or more possible values of CIF for the given DCI format size, shall assume that a PDCCH candidate with the given DCI format size may be transmitted in the given serving cell in any PDCCH UE specific search space corresponding to any of the possible values of CIF for the given DCI format size.

If a serving cell is a LAA Scell, and if the higher layer parameter subframeStartPosition for the Scell indicates 's07',.

If a serving cell is a LAA Scell, the UE may receive PDCCH with DCI CRC scrambled by CC-RNTI as described in subclause 13A on the LAA Scell.

The DCI formats that the UE shall monitor depend on the configured transmission mode per each serving cell as defined in subclause <NUM>.

If a UE is configured with higher layer parameter skipMonitoringDCI-format0-1A for a serving cell, the UE is not required to monitor the PDCCH with DCI Format <NUM>/1A in the UE specific search space for that serving cell.

If a UE is configured with higher layer parameter pdcch-candidateReductions for a UE specific search space at aggregation level L for a serving cell, the corresponding number of PDCCH candidates is given by <MAT>, where the value of a is determined according to Table <NUM>. <NUM>-<NUM> and <MAT> is determined according to Table <NUM>. <NUM>-<NUM> by replacing M(L) with <MAT>.

For the common search spaces, Yk is set to <NUM> for the two aggregation levels L = <NUM> and L = <NUM>.

For the UE-specific search space <MAT> at aggregation level L, the variable Yk is defined by <MAT> where Y-<NUM> = nRNTI ≠ <NUM>, A = <NUM>, D = <NUM> and <MAT>, ns is the slot number within a radio frame.

The RNTI value used for nRNTI is defined in subclause <NUM> in downlink and subclause <NUM> in uplink.

When it comes to NR, the story becomes somehow different, as backward compatibility is not a must. Numerology can be adjusted so that reducing symbol number of a TTI would not be the only tool to change TTI length. Using LTE numerology as an example, it comprises <NUM> OFDM symbol in <NUM> and a subcarrier spacing of <NUM>. When the subcarrier spacing goes to <NUM>, under the assumption of same FFT size and same CP structure, there would be <NUM> OFDM symbols in <NUM>, equivalently the TTI become <NUM> if the number of OFDM symbol in a TTI is kept the same. This implies the design between different TTI lengths can be kept common, with good scalability performed on the subcarrier spacing. Of course, there would always be trade-off for the subcarrier spacing selection, e.g., FFT size, definition/number of PRB, the design of CP, supportable system bandwidth,. While as NR considers larger system bandwidth, and larger coherence bandwidth, inclusion of a larger sub carrier spacing is a nature choice.

As discussed above, it is very difficult to fulfill all diverse requirements with a single numerology. Therefore, it is agreed in the very first meeting that more than one numerology would be adopted. And considering the standardization effort, implementation efforts, as well as multiplexing capability among different numerologies, it would be beneficial to have some relationship between different numerologies, such as integral multiple relationship. Several numerology families, were raised, one of them is based on LTE <NUM>, and some other numerologies (Alt2~<NUM> below) which allows power N of <NUM> symbols in <NUM>:.

Also, whether there would be restriction on the multiplier of a given numerology family is also discussed, power of <NUM> (Alt <NUM> below) drew some interests as it can multiplex different numerology easier without introducing much overhead when different numerologies is multiplexed in time domain:.

Usually, RAN1 works as band agnostic manner, i.e. a scheme/feature would be assumed to be applicable for all frequency bands and in the following RAN4 would derive relevant test case considering if some combination is unrealistic or deployment can be done reasonably. This rule would still be assumed in NR, while some companies do see there would be restriction for sure as the frequency range of NR is quite high:.

URLLC (Ultra-Reliable and Low Latency Communication) is a service type that has a very tight timing requirement, comparing with most of regular traffic, e.g., eMBB (Enhanced Mobile Broadband) service. To fulfill the latency requirement, the transmission interval/scheduling interval would need to be short. One way to shorten the transmission interval/scheduling interval is to increase the subcarrier spacing so as to reduce the OFDM symbol length in the time domain. For example, when subcarrier spacing is <NUM>, <NUM> OFDM symbols transmission interval would occupy <NUM> while when subcarrier spacing is <NUM>, 7OFDDM symbols transmission interval would occupy <NUM>, which can fulfil the stringent timing requirement easier.

Another way is to reduce the number of OFDM symbols within a transmission interval. For example, if the subcarrier spacing is kept as <NUM>, when the number of OFDM symbol within a transmission interval is reduced from <NUM> to <NUM>, the transmission time interval would be changed from <NUM> to about <NUM>, which result in similar effect of reducing subcarrier spacing.

The two ways of course can be used jointly. On the other hand, eMBB service might also use a reduced transmission interval while not necessarily always to do so as it would come with some potential side effect, e.g., larger control signaling overhead per amount of data traffic, shorter or more frequent control channel reception interval (may increase power consumption), shorter processing time (more complexity). Therefore, it is expected the communication system would be operated with different transmission intervals for different services or UEs. And multiplexing different transmission time interval within a system would be a challenge. There are some ongoing discussions on this aspect from RAN1 #86bis Chairman's Note as follows:.

Also, RAN1 #86bis Chairman's Note and RAN1 #<NUM> Chairman's Note describe how to define transmission interval as scheduling unit, such as slot or min-slot (shortened version of slot) with y is the number of OFDM symbol within a slot, as follows:.

Also, control channel in NR (e.g., NR-PDCCH) needs to be designed for adapting different services requirements/scenarios. When to monitor the occasion and number of symbols use to carry the corresponding data would be varying for different services. The composition of a slot may also be different, e.g., which portion of a slot would be DL or which portion of a slot would be uplink could depends on traffic property. For example, pure downlink slot, pure uplink slot, or a slot with DL portion and uplink portion (associated with potential gap portion considering processing or timing advance for direction change) could be a minimum set of slot structure to be considered. It is further considered to use a group common control channel to indicate slot structure as follows:.

The content of group common PDCCH and how to reveal the slot structure information is unclear. One key factor is how to group the UE. One example of grouping is to group UE with similar service requirements (e.g., the same numerology, the same RTT or timing relationship), or the same length of data duration (e.g., the same length of mini-slot). If the property of UE grouped together is more similar, the slot structure is more regular and the information amount related to slot structure could be less.

For example, if all UE has a same mini slot length, the number of mini-slot with in a slot could be known by dividing the slot length with a mini-slot length, so as to allow UE realize which symbol is DL or UL or which symbol is control or data. Taking <NUM> symbol mini slots as an example. If the number of symbol can be used to carry mini slot is <NUM> and UE is indicated a mini-slot length of <NUM> symbols, the UE knows that symbols <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may contain control information which requires PDCCH monitoring, while <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> do not contain control information which does not require PDCCH monitoring. Note that in the example, mini slots include the symbol for control information, while even if mini slot does not include control channel, similar situation can be observed.

Another example is the number of DL symbol or UL symbol. For example, if all UEs in a group has a same ratio of DL symbol and UL symbol (e.g., after every <NUM> DL symbols there is one UL symbol), the UE may know that symbols <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are downlink symbols and symbols <NUM>, <NUM>, and <NUM> are uplink symbols, if a ratio (or the total number of symbols as well) are indicated in the group common PDCCH for the UEs. (Note that potential gap symbols are not considered in the above example, while similar situation can be observed if gap symbol exist. The above example can be considered as "regular" slot structure.

On the other hand, if the slot structure is not regular (e.g., some UE(s) may use <NUM> symbol mini slots while some other UE(s) may use <NUM> symbol mini-slots), more detailed information is required for UE to know which symbol is control/data, and which symbol is UL/DL comparing with knowing the structure with one or a few factor(s) for regular structure case. A worst case could be using a bitmap for indicating the slot structure revealing the role (DL or UL control, or data) of each symbol which could be a quite significant overhead.

It is observed that if the structure is more regular, the overhead of each group common PDCCH can be reduced, while the number of group common PDCCH would increase as the number of group increase accordingly (UEs in a group have to be quite similar). On the other hand, if the structure is more irregular, the overhead of each group common PDCCH would be increased, while he number of group common PDCCH is reduced as the number of group is reduced (UEs in a group don't have to be that similar). Which direction leads to less overall control signaling overhead may depend on situation, so that proper tradeoff/adaptation between two sides may need to be considered.

A first concept of this invention is, in general, the UEs can be indicated with two modes to realize the slot structure. One mode leads to regular slot structure where the slot structure comprises several minimum function blocks. The minimum function blocks are identical from at least from the UE side in a same slot. Identical from UE side means every X symbol UE would expect a symbol with a same functionality (e.g., UL or DL control or data). More specifically, group common PDCCH may indicate the value of X, and/or information to allow UE deriving X, and/or information to allow UE the functionality of each symbol within minimum function blocks (symbol <NUM>~symbol X). Another mode leads to allowing irregular slot structure where the slot structure can be known on a per symbol basis, e.g., using a bit map to indicate the functionality of each symbol where a least one bit corresponding to one symbol within a slot.

A second concept is generally a base station groups UE(s) with different properties in a group common PDCCH while different UEs expect a regular structure with different minimum function blocks. The UEs receiving group common PDCCH may interpret or determines the slot structure with different minimum function blocks according to some pre-configurations. Furthermore, the difference of deriving the slot configuration may suffer from some constraint. One example of the difference is a length of the minimum function block of a first UE is an integer multiple of a length of the minimum function block of a second UE. For example, the first UE may expect every <NUM>*X symbol there is a symbol with a same functionality. On the other hand, the second UE may expect every X symbol there is a symbol with a same functionality.

Another example of the difference is that different UEs have a same length of minimum function block while have different understanding regarding functionality of each symbol within a minimum function block. For example, a first UE expects the first symbol of every X symbol containing control information (e.g., not other symbols) and a second UE expects the first two symbols of every X symbol containing control information (e.g., not other symbols).

Preferably, a UE is informed/configured a mode for determine a slot structure according to a group common PDCCH by a base station. Preferably, there are two modes for determining slot structure for a slot according to a group common PDCCH associated with the slot.

A first mode could be a regular slot structure mode in which UE determines the same functionality for an OFDM symbol every X OFDM symbol (e.g., <NUM>, <NUM>, and <NUM> would have a same functionality if X=<NUM>). Preferably, the functionality comprises all or some or combinations of DL, UL, data, control symbol. In the first mode, the base station could indicate the length of minimum function block in a group common PDCCH. The functionality could comprise all or some or combinations of DL, UL, data, control symbol.

Preferably in the first mode, the base station would indicate the length of minimum function block in a pre-configuration or RRC (Radio Resource Control) message. The base station could indicate the functionalities of each symbol within a minimum function block in a group common PDCCH. According to the invention, the base station indicates the functionalities of each symbol within a minimum function block in a RRC message. In a related art, the base station could also indicate the functionalities of each symbol with a minimum function block in a pre-configuration.

A second mode could be an irregular slot structure mode in which UE cannot derive the slot structure with one minimum function block. Preferably in the second mode, the UE could be configured with more than one minimum function blocks. The UE could be informed which minimum function block is included in which portion of a slot via a group common DCI associated with the slot. The UE could also be informed of a presence and/or a sequence of configured minimum function blocks.

The UE can be configured with certain restriction for transmission or reception for the minimum function block by a base station. For example, the restriction could be the UE would receive or transmit for one type of minimum function block while skip a second type of minimum function block in a slot. Preferably, the type of minimum function block could be characterized by a length of minimum function block. The type of minimum function block could also be characterized by the composition of the minimum function block, such as functionality of each symbol in the minimum function block.

Preferably in the second mode, the UE could be provided with functionality of each symbol in a slot via a group common PDCCH associated with the slot by a base station. The UE could be configured with certain restriction to skip some portion of a slot by the base station, e.g., if the DL portion is too short/too long according to the bitmap.

According to the invention, a base station configures UE with different type of minimum function blocks to receive a same group common PDCCH. A UE is configured with a type of minimum function block, and interprets or determines the slot structure of a slot according to the configured minimum function block type as well as the group common PDCCH associated with the slot. Preferably, the type of minimum function block could be characterized by a length of minimum function block. More specifically, the UEs receiving a same group common PDCCH would have different lengths of minimum function block, while one length among the different lengths is an integer multiple of length among the different lengths. The type of minimum function block is characterized by functionality of each symbol in the minimum function block, preferably by the composition of the minimum function block. More specifically, the UEs receiving a same group common PDCCH would have the same length of minimum function block.

With a correct understanding of slot structure, the UE could receive or transmit each symbol accordingly, e.g., for control or data reception or transmission.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a UE. In step <NUM>, the UE receives a configuration which indicates functionalities of each symbol within a minimum function block. In step <NUM>, the UE determines a slot structure for a slot according to a group common PDCCH associated with the slot and the configuration.

Preferably, the UE cannot derive a slot format according to the group common PDCCH without the configuration.

The configuration is signaled by a RRC (Radio Resource Control) message, and could be specifically for the UE. Furthermore, the configuration indicates different functionalities of each symbol within different minimum function blocks. The UE could receive information regarding which configured set of symbols is present.

Preferably, the minimum function block could be a basic unit for a group common PDCCH to provide information.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a UE, the device <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the UE (i) to receive a configuration which indicates functionalities of each symbol within a set of symbols, and (ii) to determine a slot structure for a slot according to a group common PDCCH associated with the slot and the configuration. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

<FIG> is a flow chart <NUM> according to one exemplary embodiment from the perspective of a base station. In step <NUM>, the base station signals a first configuration to a first UE which indicates functionalities of each symbol within a minimum function block. In step <NUM>, the base station determines for the first UE the slot structure for a slot according to a group common PDCCH associated with the slot and the first configuration.

Preferably, the base station could signal a second configuration to a second UE which indicates functionalities of each symbol within a minimum function block. The base station could determine for the second UE the slot structure for the slot according to the group common PDCCH associated with the slot and the second configuration. The base station could configure the first UE and the second UE to receive a same group common PDCCH. Preferably, the first UE and the second UE could have different understandings regarding slot structure of a same slot according to the same group common PDCCH.

The base station configures the UE (e.g., the first UE and/or the second UE) different functionalities of each symbol within different minimum function blocks. Preferably, the base station could also inform the UE which configured set of symbols is present.

Referring back to <FIG> and <FIG>, in one exemplary embodiment of a base station, the device <NUM> includes a program code <NUM> stored in the memory <NUM>. The CPU <NUM> could execute program code <NUM> to enable the base station (i) to signal a first configuration to a first UE which indicates functionalities of each symbol within a set of symbols, and (ii) to determine for the first UE the slot structure for a slot according to a group common PDCCH associated with the slot and the first configuration. Furthermore, the CPU <NUM> can execute the program code <NUM> to perform all of the above-described actions and steps or others described herein.

Various aspects of the disclosure have been described above. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. As an example of some of the above concepts, in some aspects concurrent channels may be established based on pulse repetition frequencies. In some aspects concurrent channels may be established based on pulse position or offsets. In some aspects concurrent channels may be established based on time hopping sequences. In some aspects concurrent channels may be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.

Those of skill would 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.

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.

Claim 1:
A method of a User Equipment, in the following also referred to as UE, comprising:
the UE receives a configuration which indicates a type of a minimum function block, wherein the type of a minimum function block means functionalities of each symbol within the minimum function block (<NUM>); and
the UE determines a slot structure for a slot according to a group common Physical Downlink Control Channel, in the following also referred to as PDCCH, associated with the slot and the configuration (<NUM>),
the configuration is signaled by a Radio Resource Control, in the following also referred to as RRC, message, and
the configuration indicates different types of different minimum function blocks.