Method and apparatus for downlink control physical structure

Abstract

The present disclosure relates to methods and apparatus for downlink control physical structure. A method and apparatus for signaling of higher layer messages can be provided. A higher layer message can be received by a device from a base station, the higher layer message for monitoring a control channel candidate in at least one shortened transmission time interval in a subframe and monitoring a set of resource blocks corresponding to the control channel candidate in the at least one shortened transmission time interval; it can be determined whether at least one resource block in the set of resource blocks at least partially overlaps with a broadcast control channel or signal; based on the determination of whether at least one resource block in the set of resource blocks at least partially overlaps with a broadcast control channel or signal, a control resource element for transmission of the control channel candidate can be determined; and the control channel candidate can be attempted to be decoded in the at least one shortened transmission time interval according to the determined control resource element.

Description

[0001] This application is a divisional of application PCT / US2018 / 037405, entered into the Chinese national phase on December 5, 2019, having an international filing date of June 13, 2018, Chinese application number 201880037338.0, and titled “Methods and Apparatus for Downlink Control Physical Structure.” TECHNICAL FIELD

[0002] The present disclosure relates to a method and apparatus for signaling on a wireless network. More specifically, the present disclosure relates to a method and apparatus for downlink control physical structure in reduced latency operation. BACKGROUND

[0003] Currently, 5th Generation (5G) New Radio (NR) wireless systems (abbreviated as 5G NR) provide improved wireless network technology. 5G NR includes technology for millimeter wave bands such as 26 GHz, 28 GHz, 38 GHz, and 60 GHz, and can provide a theoretical throughput of up to 20 gigabits per second with a median bandwidth of approximately 3.5 gigabits. 5G NR can utilize multiple-input multiple-output (MIMO) (e.g., 64 to 256 antennas) to provide up to ten times the performance of 4th Generation (4G) networks. In current 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), time-frequency resources can be partitioned into subframes, where each 1 ms subframe can include two 0.5 ms slots, and each slot (such as with normal cyclic prefix (CP) duration) can include 7 single-carrier frequency-division multiple access (SC-FDMA) symbols in the time domain for uplink (UL) and 7 orthogonal frequency-division multiplexing (OFDM) symbols in the time domain for downlink (DL). In the frequency domain, resources within a slot can be partitioned into physical resource blocks (PRBs), where each resource block can span twelve contiguous subcarriers. BRIEF DESCRIPTION OF DRAWINGS

[0004] In order to describe the manner in which the advantages and features of the disclosure can be obtained, a description of the disclosure will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only example embodiments of the disclosure and are therefore not to be considered limiting of its scope. The drawings can have been simplified and are not necessarily drawn to scale nor to precise proportions. Identical or similar elements are denoted by the same reference numerals throughout the several views.

[0005] Figure 1 is an example block diagram of a system according to possible embodiments;

[0006] Figure 2 illustrates a downlink (DL) short transmission time interval (sTTI) pattern according to example agreements;

[0007] Figure 3 FIGURE illustrates an example sTTI DL pattern according to a possible embodiment;

[0008] Figure 4 FIGURE illustrates another example sTTI DL pattern according to a possible embodiment;

[0009] Figure 5 FIGURE illustrates an example short resource block group (sRBG) according to a possible embodiment;

[0010] Figure 6 FIGURE illustrates another example sRBG according to a possible embodiment;

[0011] Figure 7 FIGURE illustrates yet another example sRBG according to a possible embodiment;

[0012] Figure 8 FIGURE illustrates an example illustration of a 1 symbol length based cell-specific reference signal (CRS) short physical downlink control channel (sPDCCH) according to a possible embodiment;

[0013] Figure 9 FIGURE illustrates an example 3 symbol sTTI according to a possible embodiment;

[0014] Figure 10 FIGURE illustrates an example illustration showing a demodulation reference signal (DMRS) sharing example between a DMRS based sPDCCH and a short physical downlink shared channel (sPDSCH) according to a possible embodiment;

[0015] Figure 11 FIGURE illustrates another DMRS sharing example between a DMRS based sPDCCH and a sPDSCH according to a possible embodiment;

[0016] Figure 12 FIGURE illustrates an example sCCE structure according to a possible embodiment;

[0017] Figure 13 FIGURE illustrates another example sCCE structure according to a possible embodiment;

[0018] Figure 14 FIGURE illustrates an example sRBG where two sRBGs can overlap with physical broadcast channel (PBCH) resources according to a possible embodiment;

[0019] Figure 15 FIGURE illustrates an example of different control resource mappings according to a possible embodiment;

[0020] Figure 16 FIGURE illustrates an example sTTI DL pattern according to a possible embodiment; Figure 15Examples similar to those shown in the middle but with examples of a single sRBG of twelve (12) RBs;

[0021] Figure 17 illustrates an example flow diagram illustrating operations of a device, such as a user equipment, according to possible embodiments;

[0022] Figure 18 illustrates another example flow diagram illustrating operations of a device, such as a user equipment, according to possible embodiments;

[0023] Figure 19 illustrates an example flow diagram illustrating operations of a device, such as a network entity, according to possible embodiments;

[0024] Figure 20 illustrates another example flow diagram illustrating operations of a device, such as a network entity, according to possible embodiments; and

[0025] Figure 21 illustrates an example block diagram of a device according to possible embodiments. DETAILED DESCRIPTION

[0026] Embodiments provide a method and apparatus for downlink signaling of higher layer messages. According to possible embodiments, a higher layer message from a base station can be received, the higher layer message indicating to monitor a control channel using demodulation reference signals in a shortened transmission time interval in a subframe, wherein the higher layer can be higher than a physical layer, and wherein the shortened transmission time interval can be shorter than a subframe length transmission time interval. A first control channel candidate in the shortened transmission time interval can be attempted to be decoded, wherein the first control channel candidate can include a first shortened control channel element that can span a first set of shortened resource element groups in a frequency domain using a first demodulation reference signal on a first antenna port, wherein a first precoder can be applied to all demodulation reference signal resource elements in the first set of shortened resource element groups, wherein the shortened control channel element can correspond to the shortened transmission time interval. A second control channel candidate in the shortened transmission time interval can be attempted to be decoded, wherein the second control channel candidate can include a second shortened control channel element that can span a second set of shortened resource element groups in the frequency domain using a second demodulation reference signal on a second antenna port, wherein a second precoder can be applied to all demodulation reference signal resource elements in the second set of shortened resource element groups. A first shortened resource element group in the first set of shortened resource element groups can occupy a first set of resource elements in a given resource block in a first orthogonal frequency division multiplexing symbol of the shortened transmission time interval, and a second shortened resource element group in the second set of shortened resource element groups can occupy a second set of resource elements in the given resource block in a second orthogonal frequency division multiplexing symbol of the shortened transmission time interval, wherein the first orthogonal frequency division multiplexing symbol can be different from the second orthogonal frequency division multiplexing symbol.

[0027] Embodiments provide another method and another apparatus for downlink signaling of higher layer messages. According to possible embodiments, a higher layer message can be transmitted by an apparatus, the higher layer message indicating to monitor a control channel using demodulation reference signals in a shortened transmission time interval within a subframe, wherein the higher layer can be higher than a physical layer, and wherein the shortened transmission time interval can be shorter than a subframe length transmission time interval. A first control channel candidate within the shortened transmission time interval can be transmitted, wherein the first control channel candidate can include a first shortened control channel element that can span a first set of shortened resource element groups in a frequency domain using a first demodulation reference signal on a first antenna port, wherein a first precoder can be applied to all demodulation reference signal resource elements in the first set of shortened resource element groups, wherein the shortened control channel element can correspond to the shortened transmission time interval. A second control channel candidate within the shortened transmission time interval can be transmitted, wherein the second control channel candidate can include a second shortened control channel element that can span a second set of shortened resource element groups in the frequency domain using a second demodulation reference signal on a second antenna port, wherein a second precoder can be applied to all demodulation reference signal resource elements in the second set of shortened resource element groups. A first shortened resource element group in the first set of shortened resource element groups can occupy a first set of resource elements in a given resource block in a first orthogonal frequency division multiplexing symbol of the shortened transmission time interval, and a second shortened resource element group in the second set of shortened resource element groups can occupy a second set of resource elements in the given resource block in a second orthogonal frequency division multiplexing symbol of the shortened transmission time interval, wherein the first orthogonal frequency division multiplexing symbol can be different from the second orthogonal frequency division multiplexing symbol.

[0028] Embodiments provide another method and another apparatus for downlink signaling of higher layer messages. According to possible embodiments, a higher layer message can be received from a base station, the higher layer message for monitoring a control channel candidate within at least one shortened transmission time interval within a subframe and monitoring a set of resource blocks corresponding to the control channel candidate within the at least one shortened transmission time interval, wherein the higher layer can be higher than a physical layer, and wherein the shortened transmission time interval can be shorter than a subframe length transmission time interval. A determination can be made as to whether at least one resource block in the set of resource blocks at least partially overlaps with a broadcast control channel or signal. Control resource elements for transmission of the control channel candidate can be based on the determination as to whether the at least one resource block in the set of resource blocks at least partially overlaps with the broadcast control channel or signal. An attempt can be made to decode the control channel candidate within the at least one shortened transmission time interval according to the determined control resource elements, wherein the control channel candidate includes a shortened control channel element that spans a set of shortened resource element groups in a frequency domain.

[0029] Embodiments provide another method and another apparatus for downlink signaling of higher layer messages. According to possible embodiments, a higher layer message can be transmitted, the higher layer message for monitoring a control channel candidate in at least one shortened transmission time interval in a subframe and monitoring a set of resource blocks corresponding to the control channel candidate in the at least one shortened transmission time interval. The higher layer can be higher than a physical layer. The shortened transmission time interval can be shorter than a subframe length transmission time interval. At least one resource block in the set of resource blocks can at least partially overlap with a broadcast control channel or signal. A control resource element for transmitting the control channel candidate can be determined, the control resource element at least partially overlapping in frequency with the broadcast control channel or signal based on the at least one resource block in the set of resource blocks. A control channel candidate in the at least one shortened transmission time interval according to the determined control resource element can be transmitted. The control channel candidate can include a shortened control channel element across a set of shortened resource element groups in a frequency domain.

[0030] Figure 1 An example block diagram of a system 100 is illustrated in accordance with possible embodiments. The system 100 can include a user equipment (UE) 110, at least one of network entities 120 and 125 (such as base stations), and a network 130. The UE 110 can be a wireless wide area network apparatus, a user apparatus, a wireless terminal, a portable wireless communication apparatus, a smart phone, a cellular phone, a flip phone, a personal digital assistant, a personal computer, a selective call receiver, an Internet of Things (IoT) apparatus, a tablet computer, a laptop computer, or any other user apparatus capable of sending and receiving communication signals over a wireless network. At least one of the network entities 120 and 125 can be a wireless wide area network base station, can be a NodeB, can be an enhanced NodeB (eNB), can be a New Radio NodeB (gNB) (such as a 5G NodeB), can be an unlicensed network base station, can be an access point, can be a base station controller, can be a network controller, can be a transmission / reception point (TRP), can be base stations of different types from each other, and / or can be any other network entity that can provide wireless access between the UE and the network. Higher layer messages 140 can include various signals transmitted from the network entity 120 and various signals received by the UE 110 described herein.

[0031] The network 130 can include any type of network capable of transmitting and receiving wireless communication signals. For example, the network 130 can include a wireless communication network, a cellular telephone network, a time division multiple access (TDMA) based network, a code division multiple access (CDMA) based network, an orthogonal frequency division multiple access (OFDMA) based network, a long term evolution (LTE) network, a 3rd Generation Partnership Project (3 GPP) based network, a satellite communication network, a high altitude platform network, the Internet, and / or other communication networks. In possible embodiments, the network entity 120 and the UE 110 can be included in a cell 135, the network entity 125 can be included in another cell 155, and the network entities 120 and 125 can be coupled via the network 130.

[0032] In operation, the UE 110 can communicate with the network 130 via the network entity 120. For example, the UE 110 can transmit and receive control signals on a control channel and user data signals on a data channel.

[0033] In current LTE systems, resources can be allocated using a minimum transmission time interval (TTI) of 1 ms when data is available, which is referred to as dynamic scheduling. Within each scheduled TTI, in the UL, the UE 110 can transmit data to the UE 110 scheduling the data transmission in PRB pairs indicated by an uplink grant on a physical uplink shared channel (PUSCH). In the DL, the network entity 120 can transmit data in PRB pairs indicated by a DL grant / allocation on a PDSCH. The UL grant and / or DL allocation information can be provided to the UE 110 in a physical channel, which is referred to as a PDCCH or an enhanced PDCCH (EPDCCH). The (E)PDCCH channel can carry control information about data being transmitted on the current subframe as well as information about resources that the UE 110 needs to use for uplink data.

[0034] There can be two types of downlink physical layer control signaling for the purpose of dynamic scheduling. One type of downlink physical layer control signaling for the purpose of dynamic scheduling can be a PDCCH, where control signaling from the network entity 120 can be received by the UE 110 in the first, first two, or first three, or first four symbols in a subframe, which are hereinafter referred to as control symbols. The remaining symbols in the subframe after the control symbols can generally be used for receiving user data. The user data can be received by the UE 110 on a PDSCH and in selected resource blocks (RBs) of the PDSCH, which can occupy the entire carrier bandwidth or a portion thereof.

[0035] A set of PDCCH candidates to be monitored is defined according to a search space, wherein the search space at an aggregation level L e {1, 2, 4, 8} can be defined by a set of PDCCH candidates For each serving cell at which PDCCH can be monitored, a control channel element (CCE) corresponding to a PDCCH candidate of the search space may be derived by a formula that employs a parameter including a total number of CCEs in a control region of a subframe, such as derived from a reduction of physical control format indicator channel (PCFICH) and physical channel hybrid-ARQ indicator channel (PHICH) resources, an aggregation level, a number of PDCCH candidates to be monitored in a given search space, and a slot number within a radio frame.

[0036] A physical control channel can be transmitted on an aggregation of one or several consecutive CCEs, wherein a control channel element can correspond to a group of 9 resource elements. Each CCE can be equivalent to 36 resource elements (REs). One CCE can be a minimum PDCCH allocation unit.

[0037] A number of resource element groups not allocated to PCFICH or PHICH can be N REG CCEs available in the system 100 can be numbered from 0 to N CCE - 1, wherein A PDCCH can consist of n consecutive CCEs and can only start on a CCE satisfying i mod n = 0, wherein i can be a CCE number.

[0038] Another type of downlink physical layer control signaling for the purpose of dynamic scheduling can be an EPDCCH. For each serving cell, a higher layer signaling including a higher layer message 140 can configure a UE 110 with one or two EPDCCH-PRB sets for EPDCCH monitoring. A PRB pair corresponding to an EPDCCH-PRB set can be indicated by a higher layer. Each EPDCCH-PRB set can consist of a set of enhanced control channel elements (ECCEs) numbered from 0 to N ECCE，p，k - 1, wherein N ECCE，p，k may be a number of ECCEs in an EPDCCH-PRB set p of a subframe k. Each EPDCCH-PRB set can be configured for localized EPDCCH transmission or distributed EPDCCH transmission.

[0039] For each serving cell, the subframes in which the UE 110 monitors the EPDCCH UE-specific search space can be configured by higher layers. The UE 110 can monitor a set of (E)PDCCH candidates for control information, where monitoring can imply attempting to decode each (E)PDCCH decoding candidate in the set according to the monitored downlink control information (DCI) format. The set of (E)PDCCH candidates to monitor can be defined according to the (E)PDCCH search space.

[0040] To reduce communication latency in LTE, various schemes are being investigated. For example, methods envisioned for future LTE systems can include using shorter minimum TTIs in UL / DL, such as shorter than 1 ms. Using sTTIs, such as minimum sTTIs, can allow the UE 110 to transmit / receive data with reduced latency compared to the current LTE system. In addition, acknowledging each sTTI (or group containing several sTTIs) makes the speed faster compared to using a 1 ms TTI, and acknowledging data during the slow start phase can help some applications, such as the transmission control protocol (TCP), for users in good channel conditions. For example, in the TCP slow start phase for DL communication, the network 130-UE 110 link capacity for a UE 110 in good channel conditions can support more data, but the network 130 can transmit a smaller amount of data because the network 130 can be waiting to receive an acknowledgement for previously transmitted data due to the TCP slow start phase. Therefore, faster acknowledgements, such as a result of using shorter TTI lengths, can enable the network 130 to better utilize the available network 130-UE 110 link capacity.

[0041] The currently supported sTTI configurations within a subframe can be (A) a combination of 6 sTTIs, each consisting of two or three symbols (such as OFDM symbols in DL, or SC-FDMA symbols in UL), respectively; or (B) two sTTIs of 0.5 ms length. For example, scheduling UE 110 transmissions within a 0.5 ms sTTI length (such as using PUSCH scheduled across 0.5 ms PRBs in a 1 ms subframe) or scheduling UE 110 transmissions within a sTTI length of about 140 us (such as using PUSCH scheduled across two SC-FDMA symbols in a shortened PRB within a slot in a subframe) not only reduces the time taken to start / complete a transmission data packet, but also potentially reduces the round trip time for possible hybrid automatic repeat request (HARQ) retransmissions related to that data packet.

[0042] The PDCCH channel can carry control information about the data being transmitted on the current subframe and information about the resources that the UE 110 needs to use for uplink data. If the UE 110 wishes to transmit some data or receive certain information, it can decode it. To reduce latency, a shortened physical downlink control channel (sPDCCH) can be defined to play a similar role in sTTIs or groups of sTTIs. For PDCCH, resource allocation can be in terms of CCEs, which can be equivalent to 36 REs. One CCE can be the minimum PDCCH allocation unit.

[0043] As the sTTI length can become shorter, control overhead can increase, which in turn can increase complexity and thus processing delay, and can have a negative impact on the latency reduction provided by low latency operation. To reduce control signal overhead, multiple sTTIs can be scheduled via a single grant, such as sent via sPDCCH or (E)PDCCH order, which can be referred to as multi-sTTI scheduling. In another embodiment, to reduce control signal overhead, control information can be sent in a hierarchical manner, such as in more than one step. For example, a first step can provide a subset of control information common to a set of sTTIs at a first time instance, and a second step can provide supplemental control information related to each sTTI at a second time instance. Yet another approach can include sending control information within each scheduled sTTI, but with some DCI bit field reduction compared to DCI for legacy 1 ms-TTI. For example, for 2 / 3 symbol sTTI, the resource block group (RBG) size, which can be referred to as shortened RBG (sRBG) for sTTI, can be 2 to 6 times larger than the resource block group size used for legacy 1 ms-TTI, for example.

[0044] Figure 2 A DL sTTI pattern 200 is illustrated that shows an example agreement. According to possible 3GPP agreements, for 2-symbol DL TTI, the sTTI pattern 200 shows the OFDM symbols per subframe that a 2 / 3 OFDM symbol sTTI configuration can support. For control channels (CCs) configured with 2-symbol sTTI operation, for cross-carrier scheduled CCs, the starting symbol index of the first potential shortened PDSCH (sPDSCH) can be configured by radio resource control (RRC). For self-carrier scheduled CCs, the starting symbol index of the first potential sPDSCH can be equal to the control format indicator (CFI) value indicated by PCFICH.

[0045] The UE 110 can determine the sTTI pattern according to Table 1.

[0046] Starting symbol index of first potential sPDSCH 2-symbol DL sTTI pattern 1,3 1 2 2

[0047] Table 1

[0048] Figure 3 An example sTTI DL pattern 300 is illustrated. Figure 4 Another example sTTI DL pattern 400 is illustrated. As shown in Table 1, CRS can be used in Figure 3 and Figure 4 each of the two example sTTI DL patterns 300 and 400 illustrated in Table 1. The illustrated DL sTTI patterns assume two-port CRS, as CRS symbols shown in Figure 3 and Figure 4 , respectively, as CRS symbols 301-304 and 401-404. The sPDCCH design principles already adopted by 3GPP can be supported, including both CRS-based and DMRS-based sPDCCH. Radio access network layer 1 (RAN1) will not pursue a DMRS pattern for sPDCCH based on code division multiplexing in frequency direction (CMD-F). Legacy PDCCH can be used to transmit shortened DCI (sDCI), such as DCI for sPDSCH and / or shortened PUSCH. Quadrature phase shift keying (QPSK) can be used for sPDCCH. Tail-biting convolutional coding can be used for sPDCCH. For CRS-based sPDCCH, in time domain, sPDCCH can be transmitted starting from the first OFDM symbol within sTTI and sPDCCH that is not mapped to PDCCH region, and the frequency resources for sPDCCH can be informed by network entity 120.

[0049] Different sPDCCH principles can be used. One or two RB sets can be configured for sPDCCH frequency resources of the UE 110 by a higher layer message 140 within higher layer signaling, where any number of RBs per set can be used. A shortened resource element group (sREG) can consist of 1 RB within 1 OFDM symbol, which includes REs for CRS and / or DMRS applied for sPDCCH based on DMRS. A sREG can consist of 1 RB within 1 OFDM symbol, which includes REs for CRS and / or DMRS applied for sPDCCH based on DMRS. For sTTI, a sREG can be equal to 1 RB within 1 OFDM symbol, which includes REs for CRS and / or DMRS applied for sPDCCH based on CRS. sPDCCH RB sets based on CRS can be configured to the UE 110 by higher layer signaling in a distributed mapping or a localized mapping of shortened CCEs (sCCEs) to sREGs. The UE 110 can be configured to monitor sPDCCH RB sets, such as up to two sPDCCH RB sets containing sTTI user safety settings (USS) within sTTI, where one sPDCCH candidate can be contained within one RB set. The UE 110 can be configured to monitor up to two sPDCCH RB sets containing sTTI user safety settings (USS) within sTTI, where one sPDCCH candidate can be contained within one RB set. For sPDCCH based on CRS, for 2 / 3 symbol sTTI, the number of OFDM symbols per RB set can be 1 or 2, which can be configured by higher layers. The number of OFDM symbols per RB set for sPDCCH based on CRS can be 1, 2, and possibly 3 symbols within a 1-slot sTTI, and can be configured by higher layers. For sPDCCH based on DMRS, for 2 / 3 symbol sTTI, the number of OFDM symbols per RB set can be, such as 2 for 2 symbol sTTI #1, 2, 3, 4, 3 for 3 symbol sTTI #1 and #5, sTTI #0, and / or 2 for 1-slot sTTI: 2, and 2 for 1-slot sTTI: 2. Space frequency block coding (SFBC) can be supported for sPDCCH based on CRS, where any number of antenna ports can be used. sPDCCH demodulation based on single port DMRS can be supported, where any size of bundling size can be used. In an example, sPDCCH demodulation based on dual port DMRS can be used, including a bundling size.

[0050] An sPDCCH RB set can be configured with at least one RR set, where re-use of EPDCCH PRB allocation can be possible, transmission schemes such as CRS-based or DMRS-based can be used, centralized sCCE or distributed sCCE to sREG mapping can be used (such as at least for CRS), and if supported DMRS-based sPDCCH can be used (where centralized or distributed sPDCCH candidate to sCCE mapping is possible), several sPDCCH candidates / aggregation levels of RB set can be used, where the same or different sPDCCH candidates for different sTTI indices are possible, several symbols within sPDCCH duration can be used at least in case of CRS-based transmission, a reference signal (RS) scrambling sequence such as a virtual cell identifier (VCID) and other information required can be used in case of DMRS-based transmission.

[0051] An sPRG size for 2 / 3 symbol sPDSCH can be N, such as an sPRG of N RBs, where N can be the same or can be system BW specific for all system BWs, and N can be down-selected from [2, 3, 4, and 6]. For up to 2-layer sPDSCH within one sTTI, each layer can be mapped to a different DL DMRS port, and each DMRS port can have an orthogonal cover code (OCC)-2 in time domain to support code division multiplexing. A DL DMRS pattern can be fixed for 2-layer 2 / 3 symbol sPDSCH, where down-selection between 3 options can be used: Option 1: X = 3, N = 1; Option 2: X = 2, N = 1; and Option 3: N > 1, X = 2N + 1 or X = 2N. N can be the number of RBs, and X can be the subcarriers per N RBs. DL DMRS can be shared between 2 consecutive sTTIs for 2 / 3 symbol sPDSCH for the same UE 110, but cross-subframe sharing can not be supported, cross-slot sharing can be used, and 3 consecutive sTTIs can be used. DL DMRS RE shifting in frequency domain can be supported when collision with CRS RE occurs.

[0052] The number of required RBs for an example sPDCCH with sCCE size of 36 and different sPDCCH ALs and symbol lengths that can exist are shown in Table 2. Table 2 further illustrates the number of required RBs for sPDCCH for different ALs and number of sPDCCH symbols assuming an example 36 RE sCCE that can be similar to a CCE used for sTTI operation can exist.

[0053]

[0054]

[0055] Table 2

[0056] Similarly, for the case of example CCE size of 48, the content shown in Table 3 illustrates the number of required RBs that can exist. Table 3 illustrates the number of RBs taken up by sPDCCH for different ALs and number of sPDCCH symbols assuming an example forty-eight (48) RE sCCE.

[0057]

[0058] Table 3

[0059] For control channel design for LTE sPDCCH, embodiments provide a scheme for determining, by the UE 110, the number of sREGs per sCCE of the UE 110, the time and frequency locations of the sREGs within the time and frequency resources available for control reception, and the control of the time and frequency resources carried within the sREGs of control.

[0060] Due to the varying number of overhead (such as due to the presence of CRS in sTTI and / or DMRS), it can be possible that a variable number of REs are available for control transmission in the control resources, even though each sCCE has a fixed number of sREGs. In possible embodiments, the number of sREGs per sCCE can be fixed, such as 3 sREGs or 4 sREGs. Imposing certain scheduling restrictions can make the number of REs available for control transmission greater than a certain threshold. Examples of these restrictions can include: not allowing DMRS-based sPDCCH within sTTIs that include CRS or within sTTIs where the control symbols of the DMRS-based sPDCCH overlap with the containing symbols of the CRS. In possible embodiments, the UE 110 can be excluded from performing (such as would not perform) monitoring of DMRS-based sPDCCH when four antenna port CRS is applied or can monitor DMRS-based sPDCCH based on a configuration sent by the network entity 120. In possible embodiments, the UE 110 can be excluded from monitoring DMRS-based sPDCCH within sTTI 3 (such as within sTTIs where two control symbols overlap with two CRS containing symbols) when four antenna port CRS is applied. The network 130 can configure the UE 110 according to whether DMRS-based sPDCCH is possible within sTTIs that include CRS or within sTTIs where the control symbols of the DMRS-based sPDCCH overlap with the containing symbols of the CRS, and thus, the UE 110 can monitor DMRS-based sPDCCH within those sTTIs if the UE 110 is configured to do so.

[0061] The DMRS-based sPDCCH can occur within the sTTI "n" including CRS or within the sTTI where the control symbols for the DMRS-based sPDCCH overlap with the CRS containing symbols only when the DMRS is shared between sTTI "n-1" and sTTI "n" and is present in sTTI "n-1". In an example, the UE 110 can assume no DMRS is transmitted for sPDCCH candidates within sTTI n and can use the DMRS REs from sTTI n-1 for demodulation of sPDCCH candidates within sTTI n, the sPDCCH candidate RE mapping within sTTI n can be such that there is no rate matching around the DMRS REs. In an example, the UE 110 can use the same subcarriers for DMRS within sTTI n-1 to attempt to decode sPDCCH within sTTI n as if the DMRS is transmitted on sTTI n. In a possible embodiment, the UE 110 can be excluded from monitoring the DMRS-based sPDCCH within sTTI 3 such as within the sTTI where two control symbols overlap with two CRS containing symbols when four antenna port CRS can be applied. In a possible example, the UE 110 can assume no DMRS is transmitted for sPDCCH candidates within sTTI n and can use the DMRS REs from sTTI n-1 for demodulation of sPDCCH candidates within sTTI n. In an example, the UE 110 can use the DMRS from sTTI n-1 that at least overlaps in frequency with the sREGs associated with sPDCCH within sTTI n. In case of PRB bundling, the DMRS REs in the bundled PRB within sTTI n-1 that have at least one PRB in the bundled PRB that overlaps in frequency with the sREGs associated with sPDCCH within sTTI n can be used for demodulation and decoding of sPDCCH within sTTI n. Assuming DMRS is shared between the previous sTTI and the current sTTI, the UE 110 can monitor the DMRS-based sPDCCH within the sTTI containing CRS or within the sTTI where the control symbols overlap with the CRS containing symbols if the UE 110 is configured to monitor the DMRS-based sPDCCH. In this case, the aggregation level (AL) or location of the control can be different between the sTTIs sharing the DMRS, but the control resources of the second sTTI can fully overlap with the control and data of the first sTTI containing the DMRS.

[0062] In an embodiment, the UE 110 can determine the number of sREGs per sCCE based on some parameters or a combination thereof. For example, for sRBG size, the CRS-based sPDCCH can be configured with 1 OFDM symbol length for at least the localized sREG to sCCE mapping. From a multiplexing perspective, multiplexing data and control or multiplexing two controls, an integer number of sCCEs can fit into the sRBG.

[0063] Figures 5 to 7 Example diagrams 500, 600, and 700 illustrating example sRBGs according to possible embodiments are shown. For example, as shown in diagram 700, two sCCEs each having 3 sREGs can fit into the sRBG size of 6 RBs 710, 712, 714, 716, 718, 722, and 722, while as illustrated in the sRBG of diagram 500, only 1 sCCE having 4 sREGs 510, 512, 514, and 516 can fit completely into the sRBG. With 4 REGs per sCCE as illustrated in diagrams 500 and 600, to multiplex a UL grant with 1 sCCE with a DL assignment with 1 sCCE, 2 sRBGs can be needed, and if not possible, reusing the unused resources in the second sRBG for DL data transmission can also be complicated. In the example shown in diagrams 500 and 600, to at least better use the resources in the second symbol of the first RBG (such as those allocated by sCCEs 610, 612, 614, and 616) for DL data transmission, the network entity 120 can configure the UE 110 to associate with sCCEs 510, 512, 514, and 516 to rate match around the DMRS in the first symbol. In other words, the network entity 120 can transmit a DMRS in RBs 510, 512, 514, and 516 in diagram 500 for another UE. In another embodiment, the network entity 120 can transmit a DMRS for DL data for the same UE 110, such as in the case that sCCEs 510, 512, 514, and 516 are a DL assignment in the first sRBG, although the DL assignment can be a CRS-based sPDCCH. In this case, if configured, the UE 110 can rate match around the DMRS in the first symbol to decode the control. In diagrams 500 and 600, in the sRBG of 6 RBs, sCCEs can contain 4 sREGs 510, 512, 514, and 516 in the first sRBG and 4 sREGs 610, 612, 614, and 616 in the second sRBG, while in Figure 7In particular embodiments, 2 CCEs (one CCE illustrated as RBs 710, 712, and 714, and the second CCE illustrated as RBs 718, 720, and 722) can each consist of 3 sREGs. Each sREG can consist of 1 RB. Assuming that sCCEs such as RBs 510, 512, 514, and 516 are used for UL grants, and RBs 610, 612, 614, and 616 are used for DL assignments, re-use of sREGs for sPDCCH can be used. Figure 5 and Figure 6 It can be difficult to use RBs in the first symbol in the first sRBG for DL data transmission in

[0064] In example embodiments, for 2-symbol CRS-based sPDCCH with DMRS-based sPDSCH, it can be easy to design using 4 sREGs per sCCE. However, this can cause significant control overhead, especially for larger ALs. To overcome this deficiency, for AL = 1 or odd AL, 4 sREGs can be used. For other even ALs, 3 sREGs / sCCE can be used, but there can be an even number of sCCEs within a sRBG. In example embodiments, a hybrid scheme of elements of solutions with respect to those discussed previously is possible, where the number of sREGs per sCCE can be selected from a finite set, but certain scheduling restrictions similar to those explained can ensure that the number of available REs for control can be greater than the minimum required.

[0065] Figure 8 An example illustration 800 of 1 -symbol length CRS-based sPDCCH is illustrated. When monitoring control candidates, network entity 120 can configure UE 110 to rate match around data DMRSes present in the control resources. In 1 -symbol CRS-based sPDCCH, UE 110 can determine control resources in sREGs in first RBs 801-803 of the first symbol by assuming rate matching around DL data DMRS REs. Data RBs are illustrated in other blocks 804-812 of CRS-based sPDCCH 800, where “D” denotes DL data DMRS. DMRSes are illustrated symbolically, and DMRSes can or can not occupy the center resources of a given RB.

[0066] In another embodiment, UE 110 may determine whether to perform rate matching around DMRS for control monitoring based at least on whether a DMRS-based sPDCCH is configured. For example, this could be useful for 1-symbol CRS-based sPDCCHs with centralized and distributed sREG-to-sCCE mappings. If DMRS is shared between two consecutive sTTIs (e.g., sTTI "n-1" and sTTI "n"), UE 110 may assume that the DMRS location is punched in the control area within sTTI "n", where the DMRS is assumed to exist within sTTI "n-1", because UE 110 does not know whether DMRS is shared between sTTI "n-1" and "n" before decoding the sPDCCH within sTTI "n". In a possible embodiment, for a DMRS-based sPDCCH, assuming that no DMRS exists within sTTI n, UE 110 can know from sTTI "n-1" that UE 110 can decode the sPDCCH. In another embodiment, if UE 110 is configured to rate match around a DMRS for sPDCCH (such as a CRS-based sPDCCH), then UE 110 can rate match around the DMRS. UE 110 can assume that a non-UE-specific precoder can be used for the DMRS in the control resources within sTTI n-1, or that a non-UE-specific precoder can be associated with the DMRS in the control resources within sTTI n-1. The sPDCCH within sTTI “n” can use the DMRS RE from sTTI “n-1” on the RB corresponding to the sPDCCH. The antenna port (AP) of the sPDCCH can be based on candidates that can be monitored within sTTI “n”. In a 3-symbol sTTI, the last two symbols in the sTTI can have DL data DMRS, and assuming no DMRS exists, control for the containing symbol (such as the first symbol in the sTTI) can be decoded. If DMRS-based sPDSCH is used in the last two symbols of a 3-symbol sTTI, then the DMRS distribution pattern in the last two symbols can be determined based on the position of sREG in the first symbol.

[0067] Figure 9 The illustration shows the symbol sTTI 900 in Example 3, such as, Figure 2 The sTTI 5 in the first symbol. The DMRS pattern of the sPDSCH can be determined based on the position of the sREG in the first symbol, as shown in the first four RBs 901 to 904 of the first symbol, where the remaining RBs 905 to 918 do not include the REG. The 3-symbol sTTI 900 includes a bundle size of 3 RBs and X = 2N+1, where each 3 RBs has 7 DMRS.

[0068] If the bundling size or DMRS distribution pattern can be different for sPDSCH and DMRS-based sPDCCH, they can share DMRS within a sRBG. In a possible embodiment, the sPDSCH bundling pattern can be prioritized. In another embodiment, both sPDCCH and sPDSCH bundling patterns can be aligned. For 3GPP protocol, in a possible embodiment, single-port DMRS based sPDCCH demodulation can be supported. In another embodiment, dual-port DMRS based sPDCCH demodulation can be supported.

[0069] Figure 10 is an example diagram 1000 illustrating an example of DMRS sharing between DMRS-based sPDCCH and sPDSCH. Figure 11 is an example diagram 1100 illustrating another example of DMRS sharing between DMRS-based sPDCCH and sPDSCH. For example, each sCCE in a 2-symbol sTTI (such as with 2-symbol sPDCCH) can use 3 sREGs, such as shown in sREGs 1001 and 1002 of the 1st symbol and sREG 1007 of the 2nd symbol in diagram 1000, or each sCCE in a 3-symbol sTTI with 3-symbol sPDCCH can use 4 sREGs, such as shown in the first two sREGs 1101 and 1102 of the 1st symbol, the 1st sREG 1107 of the 2nd symbol, and the 1st sREG 1113 of the 3rd symbol in the 1st sRBG 1020 in diagram 1100. Figure 11 The data portion of sREGs 1103 to 1106, 1108 to 1112, and 1114-1118 in diagram 1100 or the data portion of sREGs 1003 to 1006, and 1008 to 1012 in diagram 1000 including 2-symbol sTTI can respectively contain DMRS resources in RBs that do not belong to the control portion including sREGs 1101, 1102, 1107, and 1113 of the 3-symbol sTTI in diagram 1100 or do not belong to the control portion including sREGs 1001, 1002, and 1007 of the 2-symbol sTTI in diagram 1000. UE 110 can determine the DMRS pattern within the RB (such as in sREG 1008 in diagram 1000 and sREG 1102 in diagram 1100) that DMRS can be shared between data and control, such as based on the DMRS pattern for data, based on the DMRS pattern for control, and / or based on both.

[0070] Figure 12An example sCCE structure 1200 for DMRS-based sPDCCH is illustrated, where each sCCE has 3 sREGs. The RBs that make up the RB bundle, such as the control RBs, can be different for different CCE indices. For example, sCCE 0 can use a first AP and sCCE 1 can use a second AP. The AP can be based on a radio network temporary identifier (RNTI) for the UE 110 and / or the sCCE index, such as the lowest sCCE index forming the sPDCCH candidate. For example, assuming 3 sREGs (each sREG consisting of 1 RB), the example sCCE structure 1200 is possible within a 2-symbol sTTI for DMRS-based sPDCCH. "D" illustrated can represent a DMRS. The RBs in the sREGs corresponding to the 1st sCCE and the 2nd sCCE are illustrated in RBs 1202, 1204, and 1206, and 1208, 1210, and 1212, respectively. A first RB bundle and a second RB bundle are illustrated by rectangles 1214 and 1216, respectively. Figure 12 The RB bundle examples illustrated in FIGS. 1 12 and 1 13 can be used for AL = 1 candidates, such as when the control contains only 1 sCCE. In another embodiment, a higher AL, such as AL = 2, can have a different RB bundle size than the RB bundle size illustrated in FIGS. 1 12 and 1 13. Figure 12 The RB bundle size illustrated in FIG. 1 14 can be used for a higher AL, such as AL = 2, which can have a different RB bundle size than the RB bundle size illustrated in FIGS. 1 12 and 1 13.

[0071] Figure 13 Another example sCCE structure 1300 is illustrated. In possible embodiments, the example sCCE structure 1300 can be used for DMRS-based sPDCCH with 3 sREGs per sCCE (such as 1301), and a higher AL, such as AL = 2, can have a different RB bundle size and can consist of two sCCEs. "D" represents a DMRS. The RB bundle size in frequency can be 3.

[0072] The UE 1 10 can determine the location of a 1 -symbol sPDCCH within a 2 / 3- symbol sTTI or a 2-symbol sPDCCH within a 3-symbol sTTI based on one or more of the configured length of the sPDCCH, the sTTI index, and the overhead, such as reference symbol overhead. This approach can help avoid CRS overhead to reduce the number of available REs in the RBs for control resources, such as in sREGs. For example, a sPDCCH with a 2-symbol length can start in the first symbol in sTTI 1, such as in sREG 0, and a sPDCCH with a 3-symbol length can start in the 2nd symbol in sTTI 2, such as in sREG 3. Figure 3 And Figure 4 The DL sTTI patterns 300 and 400 illustrated in FIGS. 1 12 and 1 13, respectively, while for sTTI 5, a 2-symbol sPDCCH can start in the 2nd symbol in sTTI.

[0073] The PBCH in LTE can carry essential information, referred to as a Master Information Block (MIB). The PBCH can be transmitted in the first 4 OFDM symbols of the 2nd time slot of subframe 0 of a radio frame, over 6 RBs (72 subcarriers) centered around the direct current (DC) subcarrier, and each radio frame for LTE can be 10 ms and each time slot is 5 ms. The DC subcarrier can be a subcarrier whose frequency can be equal to the RF center frequency of the transmitting station.

[0074] In possible embodiments, for sTTI operation, the RBs containing the PBCH are not included in the mapping of control resources in sTTI 3 and sTTI 4. The mapping of control resources can be "sREG to sCCE mapping" and / or "sCCE to sPDCCH aggregation mapping." Figure 14 An example sRBG 1400 is illustrated, where two sRBGs 1410 and 1420 can overlap with PBCH resources 1430. The UE 110 can determine the mapping of control resources based on the presence of the PBCH. Figure 15 An example sTTI 3 and sTTI 4 1510 in a subframe that can overlap with the PBCH is illustrated. The mapping of control resources can be different from the mapping used in sTTIs that do not overlap with the PBCH. For example, if a CRS / DMRS based sPDCCH with AL = 4 can be used in sTTI 4 within two symbols, then 36 REs / sCCE are assumed, instead of having a cross- Figure 15 The sPDCCH decoding candidates of the entire example sRBG illustrated on the left in FIG. 15, for example, this can be the case for some other sTTI in the subframe / or other subframes, the candidates can span the entire resources, excluding the PBCH RBs in the left and right sRBGs.

[0075] In Figure 15 Another example illustrated in FIG. 15, an example distributed CRS based / DMRS based sPDCCH candidate 1520 can employ RBs in the central 6 RBs within sTTI 3 or sTTI 4 in subframes that do not contain the PBCH, or within other sTTIs (if the subframe contains the PBCH), a different set of RBs can be employed within the sTTI that overlaps with the PBCH, in addition to the PBCH RBs. The PBCH can span the 1st sRBG and the 2nd sRBG. Figure 15Examples of different control resource mapping are illustrated, where AL = 2 and has 4 sREG / sCCE for sTTIs in sTTI 3 and sTTI 4 that overlap in time with PBCH 1510 and for another sTTI that does not overlap with PBCH candidate 1510. In an example, as illustrated, PBCH candidate 1510 can span 1st sRBG 1512 and 2nd sRBG 1514, and sPDCCH candidate 1520 can span 1st sRBG 1522 and 2nd sRBG 1524.

[0076] Figure 16 Examples similar to those shown in Figure 15 but with a single sRBG of twelve (12) RBs are illustrated. In contrast to the examples shown in Figure 15

[0077] In another embodiment, in case sRBG can be larger than 6 RBs, sRBGs containing PBCH / overlapping with PBCH can be excluded from mapping / monitoring control information, such as, in an example, sTTI 3 and 4 have different sREG to sCCE mapping, in such sRBGs each sCCE has a different number of sREG, in such case have different monitoring rules, or have different sRBG definition in those sTTIs. These principles can be similarly applied to primary or secondary synchronization signals. If an ECCE corresponding to an EPDCCH candidate can be mapped to a PRB pair that can overlap in frequency with a transmission of PBCH or primary or secondary synchronization signal in the same subframe, then the UE 110 can be excluded from being expected to monitor that EPDCCH candidate.

[0078] ​A minimum resource allocation unit (referred to as sRBG) for resource allocation type for sTTI operation can be set, and the size can be set such that multiple systems or bandwidths (BW) related to sTTI can have the same sRBG size. The sRBG can be an integer of the RBG size that is a function of system BW. For example, for a 50 RB system BW, the RBG size is 3 RB, and for a 75 RB system BW and a 100 RB system BW, the RBG size is 4 RBs. The sRBG for a 50 RB BW can consist of 4 RBGs that generate 12 REs, and the sRBG for a 75 RB BW or a 100 RB BW can consist of 3 RBGs that generate 12 REs.

[0079] In another example, for a general design perspective across sTTI, a fixed number of sREGs per sCCE can be used. For example, the sREG can include 1 RB within 1 OFDM symbol. The legacy / regular REG can include 4 REs. The legacy / regular RB can be a unit of 84 REs, such as 21 REGs, which is 12 subcarriers times 7 symbols. Using an extended cyclic prefix, the number of symbols within a subframe can be changed to 6, and a single RB can be a unit of 72 REs, such as 18 REGs. 4 sREGs per sCCE can be considered as a conservative approach. Alternatively, 3 sREGs per sCCE can be considered, but in the case of high overhead, a higher aggregation level, or AL=1 candidate can be required, or the AL=1 candidate can be limited to a specific location. Considering that the resource allocation bits for sTTI are reduced compared to 1 ms DCI, the sPDCCH payload can be smaller than the payload of PDCCH, and fewer REs / CCEs can be used. In another embodiment, under localized sREG-to-sCCE mapping on consecutive RBs belonging to an sRBG, the sREGs forming a sCCE can be mapped to RBs in the RB set, such as when time-first mapping sCCEs does not cross the sRBG boundary.

[0080] In another embodiment, regarding how to map decoding candidates of each aggregation level to available resources in case the number of symbols per RB set can be greater than 1, each decoding candidate (such as PDCCH decoding candidate) of each aggregation level can be mapped to available resources using a frequency first mapping in which lower ALs are mapped within the first symbol and higher ALs are distributed among the symbols. This method can be used when higher ALs can not fit within the given sPDCCH resources in a single symbol. This method can also be used when UEs 110 need higher ALs that are typically not in good channel conditions and they typically cannot gain more benefit in terms of latency reduction even using a single HARQ timeline. The decoding candidate can be the number of CCE indices searched by the UE 110 in a subframe for a particular search space.

[0081] Each decoding candidate of each aggregation level can be mapped to available resources based on the RB set size within two symbols, such as less than a given number "K" of RBs in the RB set. Otherwise, decoding candidates can be mapped by a single symbol, one of the two possible symbols for a single symbol can be radio resource control (RRC) or based on UE ID and subframe / slot / sTTI index. In another embodiment, generally, DMRS based sPDCCH can be used to obtain beamforming gain, in which case, a localized sREG to sCCE mapping can be used, but in multicast broadcast single frequency network (MBSFN) subframes or in normal subframes but in sTTIs without CRS, DMRS based sPDCCH can be used to obtain frequency diversity. If configured by the network 130, UEs 110 in those sTTIs / subframes can assume DMRS based sPDCCH with localized mapping.

[0082] In another embodiment, regarding how many symbols can be considered in each RB set of DMRS based sPDCCH within 3 symbol sTTI, from a generality perspective of having two symbol sTTI, two symbols can be used in each RB set of DMRS based sPDCCH within 3 symbol sTTI. This can also avoid CRS containing symbols overlapping with control resources in sTTI 1 and 5.

[0083] According to different scenarios, different APs can be allocated for DMRS of a standalone symbol in a 3-symbol sTTI, the same AP for the same UE of sPDSCH, or can be used for CRS-based sPDSCH. The network 130 can configure one or more of the three scenarios implicitly or explicitly based on a configuration or specification, and the UE 110 can assume one or more of those scenarios. In another embodiment, in case of carrier aggregation, some component carriers (CCs) can use CRS-based sPDCCH and some CCs can use DMRS-based sPDCCH for scheduling, such as per-CC configuration. Cross-carrier scheduling from one CC of another CC can allow DMRS-based sPDCCH to schedule CRS-based sPDSCH. In another embodiment, a fallback mode can be utilized. The UE 110 can be configured to monitor DMRS-based sPDCCH, but in some subframes, if one or more of the fallback cases occur, then as a fallback, CRS-based sPDCCH can be monitored.

[0084] Figure 17 An example flowchart 1700 illustrating operations of a device, such as the UE 110, is illustrated in accordance with a possible embodiment. In 1710, a higher layer message 140 from a network entity 120, such as a base station, can be received, the higher layer message indicating to monitor a control channel using DMRS within a sTTI in a subframe, where the higher layer can be a layer higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI.

[0085] In 1720, a first control channel candidate within the sTTI can be attempted to be decoded, e.g., by the UE 110. The first control channel candidate can include a first sCCE (sCCE1) using a first DMRS across a first set of sREGs in a frequency domain on a first AP. A first precoder can be applied to all DMRS REs in the first set of sREGs, where the sCCE corresponds to the sTTI. For the sTTI, 1 sREG can be equal to 1 RB within one symbol. For example, referring to Figure 12 The first set of sREGs (sCCE1) can occupy REs, sym 0, in RB1, and the second set of sREGs (sCCE2) can occupy REs, sym 1, in RB1.

[0086] In 1730, a second control channel candidate within the sTTI can be decoded, e.g., by UE 110. The second control channel candidate can include a second sCCE that spans a second set of sREGs in the frequency domain using a second DMRS on a second AP. A second precoder can be applied to all DMRS REs in the second set of sREGs. A first sREG in the first set of sREGs can occupy a first set of REs in a given RB in a first OFDM symbol of the sTTI, and a second sREG in the second set of sREGs (sCCE2) can occupy a second set of REs in the given RB in a second OFDM symbol of the sTTI, where the first OFDM symbol can be different from the second OFDM symbol.

[0087] According to possible embodiments, some sREGs in the first set of sREGs (sCCE1) occupy the same RB in both the first OFDM symbol and the second OFDM symbol, and another sREG in the first set of sREGs (sCCE1) for a given RB occupies only one OFDM symbol. For example, referring to Figure 12 , the first set of sREGs (sCCE1) can occupy REs, sym0, in RB1, and the second set of sREGs (sCCE2) can occupy REs, sym1, in RB1. According to possible embodiments, a control candidate can include one or more CCEs. According to possible embodiments, the number of PRBs in a sCCE can be the same for each sCCE. According to possible embodiments, the control channel can be sPDCCH, and the flowchart can be performed by UE 110.

[0088] According to possible embodiments, the precoding granularity of the precoder for the first sCCE can include a number of resource blocks in the frequency domain that is equal to the number of resource blocks in the first OFDM symbol. The precoding granularity can be based on a precoder resource block group (PRG) bundling. As understood by one of ordinary skill in the art, a precoder granularity of several PRBs can mean that the same precoder can be provided for several PRBs.

[0089] According to possible embodiments, the first control channel candidate and the second control channel candidate can each comprise a single sCCE. For example, this can be used for aggregation level 1. The number of sCCEs in a control channel candidate can also be based on an sCCE aggregation level. An sCCE can comprise 3 sREGs, such as 3 RBs. According to possible embodiments, the first AP can be for an even number of control channel (sPDCCH) candidates of the size of one sCCE, and the second AP can be for an odd number of control channel (sPDCCH) candidates of the size of one CCE. According to possible embodiments, the first AP can be further based on a UE identifier (ID). For example, the UE ID can be equivalent to a user equipment identifier, such as a cell RNTI (C-RNTI). According to possible embodiments, the first AP can be further based on an index of the first sCCE.

[0090] In possible embodiments, the higher layer message can be a first higher layer message, the sTTI can be a first sTTI, and the subframe can be a first subframe, the flowchart 1700 can further include receiving a downlink signal from the base station, determining a number of CRS APs based on the received downlink signal, receiving a second higher layer message to monitor a third control channel candidate using a DMRS within at least one sTTI in a second subframe, where the second higher layer can be higher than a physical layer. The flowchart 1700 can further include, in response to receiving the second higher layer message, determining whether to monitor the third control channel candidate using the DMRS within a second sTTI of the at least one sTTI based on the determined number of CRS APs, and attempting to decode the third control channel candidate using the third DMRS within the second sTTI if it can be determined to monitor the control channel candidate using the DMRS within the second sTTI.

[0091] In possible embodiments, a control symbol in the sTTI can overlap with a CRS containing symbol. The flowchart 1700 can further include determining to exclude monitoring the sPDCCH using a given DMRS within a sTTI of the sTTI when the determined number of CRS APs can be greater than a threshold number of APs.

[0092] Figure 18 FIGURE 17 illustrates another example flowchart 1700 illustrating operations of a device, such as the UE 110, according to possible embodiments. In 1710, a higher layer message from a base station can be received, the higher layer message for monitoring a control channel candidate within at least one sTTI in a subframe and monitoring a set of RBs corresponding to the control channel candidate within the at least one sTTI, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI.

[0093] In 1820, a determination can be made as to whether at least one RB of the RB set at least partially overlaps in frequency with a broadcast control channel or signal. In 1830, a control resource RE for transmission of a control channel candidate can be determined, the control resource RE being based on the determination of whether at least one RB of the RB set at least partially overlaps in frequency with a broadcast control channel or signal.

[0094] In 1830, a control channel candidate can be decoded within the at least one sTTI according to the determined control resource RE, where the control channel candidate can include an sCCE spanning a set of sREGs in a frequency domain.

[0095] According to possible embodiments, the flowchart 1800 can further include mapping control information to the control resource RE for transmission of the control channel candidate using a first mapping if at least one RB of the RB set at least partially overlaps in frequency with a broadcast control channel or signal, and mapping control information to the control resource RE for transmission of the control channel candidate using a second mapping if none of the RB set at least partially overlaps in frequency with a broadcast control channel or signal, where the first mapping and the second mapping are different.

[0096] In an example, control information can be excluded from being mapped to at least one RB of the RB set that at least partially overlaps in frequency with a broadcast control channel or signal. In an example, if at least one RB of the RB set that at least partially overlaps in frequency with a broadcast control channel or signal belongs to a second RB set, control information can be excluded from being mapped to the second RB set, where the second RB set can be a subset of the RB set. In an example, the second RB set can form a resource block group (RBG), where the RBG can be a unit of scheduling a downlink data transmission. In an example, the RBG size can be greater than 6 resource blocks.

[0097] According to possible embodiments, if at least one RB of the RB set at least partially overlaps in frequency with a broadcast control channel or signal, the set of sREGs of the sCCE can be a first set of sREGs. According to possible embodiments, if none of the RB set at least partially overlaps in frequency with a broadcast control channel or signal, the set of sREGs of the sCCE can be a second set of sREGs. In an example, the first set of sREGs and the second set of sREGs can be different. In an example, the first set of sREGs can be a subset of the second set of sREGs.

[0098] According to possible embodiments, the control channel candidate can include a set of sCCEs, and the set of sCCEs can be a first set of sCCEs if at least one RB of the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, and the set of sCCEs can be a second set of sCCEs if none of the set of RBs overlap in frequency with the broadcast control channel or signal. In an example, the first set of sCCEs and the second set of sCCEs can be different. According to possible embodiments, the flowchart 1800 can further include monitoring the control channel using the DMRS within at least the sTTI, such as by the UE 110. In an example, at least a subset of the set of sREGs can use the DMRS on the AP, where a single layer precoder is applied to all DMRS REs in the at least the subset of the set of sREGs. In possible embodiments, the at least one sTTI can include one of the first two sTTIs in the second slot of the subframe. In possible embodiments, at least one of the set of RBs can include a synchronization signal, and REs in the at least one of the set of RBs are not used to determine control resource elements of the control channel candidate within the at least one sTTI that overlap with the synchronization signal in the time domain.

[0099] Figure 19 An example flowchart 1900 illustrating the operation of an apparatus, such as the network entity 120, is illustrated in accordance with possible embodiments. In 1910, a higher layer message can be transmitted indicating to monitor a control channel using a DMRS within an STTI in a subframe. The higher layer can be higher than a physical layer, and the STTI can be shorter than a subframe length TTI.

[0100] In 1920, a first control channel candidate within a short transmission time interval can be transmitted, such as by the network entity 120. The first control channel candidate can include a first SCCE (sCCE1) that spans a first set of SREGs in a frequency domain using a first DMRS on a first AP. A first precoder can be applied to all DMRS REs in the first set of sREGs, where the sCCE corresponds to the sTTI. For the sTTI, 1 sREG can equal 1 RB within one symbol. For example, referring to Figure 12 , the first set of sREGs (sCCE1) can occupy REs, sym 0, in RB1, and the second set of sREGs (sCCE2) can occupy REs, sym 1, in RB1.

[0101] In 1930, a second control channel candidate within the sTTI can be transmitted, e.g., by the network entity 120. The second control channel candidate can include a second sCCE that spans a second set of sREGs in the frequency domain using a second DMRS on a second AP. A second precoder can be applied to all DMRS REs in the second set of sREGs. A first sREG in the first set of sREGs can occupy a first set of REs in a given RB in a first OFDM symbol of the sTTI, and a second sREG in the second set of sREGs (sCCE2) can occupy a second set of REs in the given RB in a second OFDM symbol of the sTTI, where the first OFDM symbol can be different from the second OFDM symbol.

[0102] According to possible embodiments, some sREGs in the first set of sREGs (sCCE1) occupy the same RB in both the first OFDM symbol and the second OFDM symbol, and another sREG in the first set of sREGs (sCCE1) for a given RB occupies only one OFDM symbol. For example, referring to Figure 12 , the first set of sREGs (sCCE1) can occupy REs, sym0, in RB1, and the second set of sREGs (sCCE2) can occupy REs, sym1, in RB1. According to possible embodiments, a control candidate can include one or more CCEs. According to possible embodiments, the number of PRBs in an sCCE can be the same for each sCCE. According to possible embodiments, the control channel can be an sPDCCH, and the flowchart can be performed by the UE 110.

[0103] According to possible embodiments, the precoding granularity of the precoder for the first sCCE can include a number of resource blocks in the frequency domain that is equal to the number of resource blocks in the first OFDM symbol. The precoding granularity can be based on a precoder resource block group (PRG) bundling. As understood by one of ordinary skill in the art, a precoder granularity of several PRBs can mean that the same precoder can be provided for several PRBs.

[0104] According to possible embodiments, the first control channel candidate and the second control channel candidate can each comprise a single sCCE. For example, this can be used for aggregation level 1. The number of sCCEs in a control channel candidate can also be based on the sCCE aggregation level. A sCCE can comprise 3 sREGs, such as 3 RBs. According to possible embodiments, the first AP can be for an even number of control channel (sPDCCH) candidates of the size of one sCCE, and the second AP can be for an odd number of control channel (sPDCCH) candidates of the size of one CCE. According to possible embodiments, the first AP can be further based on a UE identifier (ID). For example, the UE ID can be equivalent to a user equipment identifier, such as a cell RNTI (C-RNTI). According to possible embodiments, the first AP can be further based on an index of the first sCCE.

[0105] Figure 20 An example flowchart 2000 illustrating operations of a device, such as the network entity 120, is illustrated in accordance with possible embodiments. In 2010, a higher layer message can be transmitted, the higher layer message for monitoring a control channel candidate within at least one sTTI in a subframe and monitoring a set of RBs corresponding to the control channel candidate within the at least one sTTI. The higher layer can be higher than a physical layer. The sTTI can be shorter than a subframe length TTI. At least one RB in the set of RBs can at least partially overlap with a broadcast control channel or signal.

[0106] In 2020, it can be determined whether at least one RB in the subset of RBs at least partially overlaps in frequency with the broadcast control channel or signal.

[0107] In 2030, a control RE for transmission of the control channel candidate can be determined, the control RE based on the determination of whether at least one RB in the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal.

[0108] In 2040, a control channel candidate within the at least one sTTI in accordance with the determined control RE can be transmitted, wherein the control channel candidate comprises a sCCE that spans a set of sREGs in a frequency domain.

[0109] According to possible embodiments, the flowchart 2000 can further comprise mapping control information to control resource REs for transmission of the control channel candidate using a first mapping if at least one RB in the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, and mapping control information to control resource REs for transmission of the control channel candidate using a second mapping if none of the RBs in the set of RBs overlap in frequency with the broadcast control channel or signal, wherein the first mapping and the second mapping are different.

[0110] In an example, the control information can be excluded from being mapped to at least one RB of the RB set that at least partially overlaps in frequency with the broadcast control channel or signal. In an example, if the at least one RB of the RB set that at least partially overlaps in frequency with the broadcast control channel or signal belongs to a second RB set, the control information can be excluded from being mapped to the second RB set, where the second RB set can be a subset of the RB set. In an example, the second RB set can form a resource block group (RBG), where the RBG can be a unit of scheduling a downlink data transmission. In an example, the RBG size can be greater than 6 resource blocks.

[0111] According to a possible embodiment, the set of sREGs of the sCCE can be a first set of sREGs if at least one RB of the RB set at least partially overlaps in frequency with the broadcast control channel or signal. According to a possible embodiment, the set of sREGs of the sCCE can be a second set of sREGs if none of the RBs of the RB set overlap in frequency with the broadcast control channel or signal. In an example, the first set of sREGs and the second set of sREGs can be different. In an example, the first set of sREGs can be a subset of the second set of sREGs.

[0112] According to a possible embodiment, the control channel candidate can comprise a set of sCCEs, and the set of sCCEs can be a first set of sCCEs if at least one RB of the RB set at least partially overlaps in frequency with the broadcast control channel or signal, and the set of sCCEs can be a second set of sCCEs if none of the RBs of the RB set overlap in frequency with the broadcast control channel or signal. In an example, the first set of sCCEs and the second set of sCCEs can be different. In a possible embodiment, the at least one sTTI can comprise one of the first two sTTIs in the second slot of the subframe. In a possible embodiment, within an sTTI that overlaps with a synchronization signal in time domain, the RBs containing the synchronization signal can be excluded from being included in the mapping of the control resource.

[0113] Figure 21Example block diagrams of device 2100 according to possible embodiments are illustrated, such as UE 110, network entity 120, network entity 125, any entity within network 130, and / or any other wireless or non-wireless communication devices disclosed herein. Device 2100 may include housing 2110, controller 2120 coupled to housing 2110, audio input and output circuitry 2130 coupled to controller 2120, display 2140 coupled to controller 2120, transceiver 2170 coupled to controller 2120, at least one antenna 2175 coupled to transceiver 2170, user interface 2160 coupled to controller 2120, memory 2150 coupled to controller 2120, and network interface 2180 coupled to controller 2120. Device 2100 may not necessarily include all illustrated elements used in the different embodiments of this disclosure. Device 2100 may perform the methods described in all embodiments.

[0114] Display 2140 may be a viewfinder, liquid crystal display (LCD), light-emitting diode (LED) display, organic light-emitting diode (OLED) display, plasma display, projection display, touchscreen, or any other device for displaying information. Transceiver 2170 may be one or more transceivers that may include a transmitter and / or a receiver. Audio input and output circuitry 2130 may include a microphone, speaker, transducer, or any other audio input and output circuitry. User interface 2160 may include a keypad, keyboard, buttons, touchpad, joystick, touchscreen display, another additional display, or any other device that can be used to provide an interface between a user and an electronic device. Network interface 2180 may be a universal serial bus (USB) interface, Ethernet port, infrared transmitter / receiver, IEEE 1394 port, wireless transceiver, WLAN transceiver, or any other interface that can connect the device to a network, device, and / or computer and can transmit and receive data communication signals. The memory 2150 may include random access memory (RAM), read-only memory (ROM), optical memory, solid-state memory, flash memory, removable memory, hard disk drive, cache, or any other memory that can be coupled to the device.

[0115] Device 2100 or controller 2120 can run any operating system, such as Microsoft. or Android TM Or any other operating system. For example, device operating software can be written using any programming language (such as C, C++, Java, or Visual Basic). Device software can also be written within application frameworks (such as, for example, frame, The software and / or the operating system can be stored in the memory 2150 or in other locations of the device 2100. The device 2100 or controller 2120 can also employ hardware to implement the disclosed operations. For example, the controller 2120 can be any programmable processor. The disclosed embodiments can also be implemented on a general-purpose computer or special purpose computer, a programmed microprocessor or microprocessor, peripheral integrated circuit elements, an application-specific integrated circuit or other integrated circuits, a hardware / software codesets, or combinations of any of the above. Typically, the controller 2120 can be any controller or processor device or devices capable of operating a device and implementing the disclosed embodiments. Some or all of the additional elements of the device 2100 can also perform some or all of the operations of the disclosed embodiments.

[0116] In operation as the UE 110, the transceiver 2170 can transmit and receive various signals described above. In a possible embodiment, for example, the transceiver 2170 can receive, from a network entity 120 (such as a base station), a higher layer message 140 indicating to monitor a control channel using a DMRS within an sTTI in a subframe, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI. In a possible embodiment, for example, the controller 2120 can attempt to decode a first control channel candidate within the sTTI. The first control channel candidate can include a first sCCE using a first DMRS on a first AP across a first set of sREGs in a frequency domain. A first precoder can be applied to all DMRS REs in the first set of sREGs, where the sCCE corresponds to the sTTI.

[0117] In a possible embodiment, for example, the controller 2120 can attempt to decode a second control channel candidate within the sTTI. The second control channel candidate can include a second sCCE using a second DMRS on a second AP across a second set of sREGs in the frequency domain. A second precoder can be applied to all DMRS REs in the second set of sREGs, where a first sREG in the first set of sREGs can occupy a first set of REs in a given RB in a first OFDM symbol, and a second sREG in the second set of sREGs can occupy a second set of REs in the given RB in a second OFDM symbol, where the first OFDM symbol can be different from the second OFDM symbol.

[0118] In addition, other possible embodiments can include a device and method that can include a transceiver 2170 to receive a downlink signal from a base station and determine a number of CRS APs based on the received downlink signal. The device and method can also include the transceiver 2170 to receive a higher layer message for monitoring control channel (sPDCCH) candidates using DMRS within at least one sTTI in a subframe, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI, and in response to receiving the higher layer message, determine whether to monitor control channel candidates using DMRS within a first sTTI of the at least one sTTI based on the determined number of CRS APs. The device and method can also include a controller 2120 to attempt to decode control channel candidates using DMRS within the first sTTI if it can be determined that control channel candidates are to be monitored using DMRS within the first sTTI. The device can be a UE 110 and the method can be performed by the UE 110. In an example, the higher layer can be higher than the physical layer because the higher layer message can be received on a layer higher than the physical layer. Control symbols within the first sTTI can overlap with CRS containing symbols, and the device and method can even further include determining not to monitor sPDCCH using DMRS within the first sTTI of the one or more sTTIs when the determined number of CRS APs can be greater than a threshold number of APs. For example, the threshold can be two APs. In a possible embodiment, when four AP CRS can be applied, the UE 110 should not monitor DMRS based sPDCCH within sTTI 3, such as within a sTTI where two control symbols overlap with two CRS containing symbols.

[0119] Another possible embodiment can include a device and method that can include a transceiver 2170 that can receive a higher layer message from a base station for monitoring control channel candidates within at least one sTTI in a subframe and monitoring a set of RBs corresponding to the control channel candidates within the at least one sTTI, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI. A controller 2120 can determine whether at least one RB of the set of RBs at least partially overlaps with a broadcast control channel or signal, and determine control REs for transmission of the control channel candidates based on the determination of whether at least one RB of the set of RBs at least partially overlaps with the broadcast control channel or signal. The controller 2120 can also attempt to decode the control channel candidates within the at least one sTTI according to the determined control REs, where the control channel candidates include sCCEs that span a set of sREGs in a frequency domain, the set of sREGs including the determined control REs.

[0120] In a possible embodiment, the controller 2120 can map the control information to the control REs used to transmit the control channel candidate using a first mapping if at least one of the RBs in the RB set at least partially overlaps in frequency with the broadcast control channel or signal, and using a second mapping if none of the RBs in the RB set overlap in frequency with the broadcast control channel or signal, where the first mapping and the second mapping are different. The control information can be excluded from being mapped to at least one of the RBs in the RB set that at least partially overlaps in frequency with the broadcast control channel or signal.

[0121] The RB set can be a first set of resource blocks, where the control information can be excluded from being mapped to a second set of resource blocks if at least one of the RBs in the first set of RBs that can at least partially overlap in frequency with the broadcast control channel or signal belongs to the second set of RBs, where the second set of RBs is a subset of the first set of RBs. The second set of RBs can form a RB group, where the RB group can be a unit of scheduling a downlink data transmission. The RB group size can be greater than 6 RBs.

[0122] The set of shortened RE groups of sCCEs can be a first set of sREGs if at least one of the RBs in the RB set at least partially overlaps in frequency with the broadcast control channel or signal, and a second set of shortened resource element groups if none of the RBs in the RB set overlap in frequency with the broadcast control channel or signal, where the first set of sREGs and the second set of sREGs can be different. The first set of sREGs can be a subset of the second set of shortened resource element groups. The control channel candidate includes a set of sCCEs, and the set of sCCEs can be a first set of sCCEs if at least one of the RBs in the RB set at least partially overlaps in frequency with the broadcast control channel or signal, and a second set of sCCEs if none of the RBs in the RB set overlap in frequency with the broadcast control channel or signal, where the first set of sCCEs and the second set of sCCEs can be different. The first set of sREGs can be a subset of the second set of sREGs. The control channel candidate can include a set of sCCEs, and the set of sCCEs can be a first set of sCCEs if at least one of the RBs in the RB set can at least partially overlap in frequency with the broadcast control channel or signal, and a second set of sCCEs if none of the RBs in the RB set can overlap in frequency with the broadcast control channel or signal, where the first set of sCCEs and the second set of sCCEs are different.

[0123] The second set of sCCEs can be a subset of the first set of sCCEs. The controller 2120 can monitor the control channel using DMRS within at least the sTTI. At least a subset of the set of sREGs can use DMRS on the AP, where a single layer precoder can be applied to all DMRS REs in the at least a subset of the set of sREGs.

[0124] The at least one sTTI can include one of the first two sTTIs in the second slot of the subframe. Within the at least one sTTI overlapping a synchronization signal in the time domain, the RB containing the synchronization signal can be excluded from being included in the mapping of the control resources. At least one RB of the set of RBs includes the synchronization signal, REs in the at least one RB of the set of RBs can be excluded from being used to determine control REs of a control channel candidate within the at least one sTTI overlapping the synchronization signal in the time domain.

[0125] In yet another possible embodiment, the transceiver 2170 can transmit a higher layer message indicating to monitor a control channel using DMRS within an sTTI of a subframe, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI. The transceiver 2170 can also transmit a first control channel candidate within the sTTI, where the first control channel candidate can include a first sCCE spanning a first set of sREGs in a frequency domain using a first DMRS on a first AP. A first precoder can be applied to all DMRS REs in the first set of sREGs, where the sREGs correspond to the sTTI. The transceiver 2170 can also transmit a second control channel candidate within the sTTI, where the second control channel candidate can include a second sCCE spanning a second set of sREGs in the frequency domain using a second DMRS on a second AP, where a second precoder can be applied to all DMRS REs in the second set of sREGs, where a first sREG in the first set of sREGs can occupy a first set of REs in a given RB in a first OFDM symbol, and a second sREG in the second set of sREGs can occupy a second set of REs in the given RB in a second OFDM symbol. The first OFDM symbol can be different from the second OFDM symbol.

[0126] According to a possible embodiment, some sREGs in the first set of sREGs (sCCE1) occupy the same RB in both the first and second OFDM symbols, and another sREG in the first set of sREGs (sCCE1) for a given RB occupies only one OFDM symbol. For example, with reference to Figure 12A first set of sREGs (sCCE1) can occupy REs, symO, in RB1 and a second set of sREGs (sCCE2) can occupy REs, syml, in RB1. According to possible embodiments, a control candidate can comprise one or more CCEs. According to possible embodiments, the number of PRBs in an sCCE can be the same for each sCCE. According to possible embodiments, the control channel can be an sPDCCH and the flowchart can be performed by a UE 110.

[0127] According to possible embodiments, a precoding granularity of a precoder for a first sCCE can comprise a number of RBs in the frequency domain equal to a number of resource blocks in a first OFDM symbol. The precoding granularity can be based on a precoder resource block group (PRG) bundling. As understood by one of ordinary skill in the art, a precoder granularity of several PRBs can mean that the same precoder can be provided for several PRBs.

[0128] According to possible embodiments, a first control channel candidate and a second control channel candidate can each comprise a single sCCE. This can be used for aggregation level 1, for example. A number of sCCEs in a control channel candidate can also be based on an sCCE aggregation level. An sCCE can comprise 3 sREGs, such as 3 RBs. According to possible embodiments, a first AP can be for an even number of control channel (sPDCCH) candidates of a size of one sCCE and a second AP can be for an odd number of control channel (sPDCCH) candidates of a size of one sCCE. According to possible embodiments, the first AP can be further based on a UE identifier (ID). The UE ID can be equivalent to a user equipment identifier, such as a cell RNTI (C-RNTI), for example. According to possible embodiments, the first AP can be further based on an index of the first sCCE.

[0129] In possible embodiments, the higher layer message can be a first higher layer message, the sTTI can be a first sTTI, and the subframe can be a first subframe, 1700 can further include receiving a downlink signal from the base station; determining a number of CRS APs based on the received downlink signal; receiving a second higher layer message to monitor a third control channel candidate using a DMRS within at least one sTTI in a second subframe, where the second higher layer can be higher than a physical layer. 1700 can further include, in response to receiving the second higher layer message, determining whether to monitor the third control channel candidate using the DMRS within a second sTTI of the at least one sTTI based on the determined number of CRS APs; and attempting to decode the third control channel candidate using a third DMRS within the second sTTI if it can be determined to monitor the control channel candidate using the DMRS within the second sTTI.

[0130] In a possible embodiment, the control symbol in the sTTI can overlap with the CRS containing symbol. 1700 can further include determining to exclude using a given DMRS within an sTTI of the sTTI to monitor for sPDCCH when the determined number of CRS APs can be greater than a threshold number of APs.

[0131] In a possible embodiment, the transceiver 2170 can receive a higher layer message from a base station for monitoring a control channel candidate within at least one sTTI in a subframe, and can receive a set of RBs corresponding to the control channel candidate within the at least one sTTI, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI. The controller 2120 can determine whether at least one RB in the set of RBs at least partially overlaps with a broadcast control channel or signal. The controller 2120 can attempt to decode the control channel candidate within the at least one sTTI according to the determined control resource REs, where the control channel candidate can include an sCCE spanning a set of sREGs in a frequency domain.

[0132] According to a possible embodiment, if at least one RB in the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, the controller 2120 can map control information to the control resource REs used to transmit the control channel candidate using a first mapping; and if none of the set of RBs overlap in frequency with the broadcast control channel or signal, the controller can map control information to the control resource REs used to transmit the control channel candidate using a second mapping, where the first mapping and the second mapping are different.

[0133] In an example, the controller 2120 can exclude mapping control information to at least one RB in the set of RBs that at least partially overlaps with the broadcast control channel or signal. In an example, if at least one RB in the set of RBs that at least partially overlaps with the broadcast control channel or signal belongs to a second set of RBs, the control information can be excluded from being mapped to the second set of RBs, where the second set of RBs can be a subset of the set of RBs. In an example, the second set of RBs can form a resource block group (RBG), where the RBG can be a unit of scheduling downlink data transmission. In an example, the RBG size can be greater than 6 RBs.

[0134] According to possible embodiments, the set of sREGs of the sCCE can be a first set of sREGs if at least one of the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, and the set of sREGs of the sCCE can be a second set of sREGs if none of the set of RBs overlap in frequency with the broadcast control channel or signal. In an example, the first set of sREGs and the second set of sREGs can be different. In an example, the first set of sREGs can be a subset of the second set of sREGs.

[0135] According to possible embodiments, the control channel candidate can comprise a set of sCCEs, and the set of sCCEs can be a first set of sCCEs if at least one of the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, and the set of sCCEs can be a second set of sCCEs if none of the set of RBs overlap in frequency with the broadcast control channel or signal. In an example, the first set of sCCEs and the second set of sCCEs can be different. In possible embodiments, the at least one sTTI can comprise one of the first two sTTIs in the second slot of the subframe. In possible embodiments, within an sTTI overlapping with a synchronization signal in time domain, the RBs containing the synchronization signal can be excluded from being included in the mapping of the control resources.

[0136] Further, another possible embodiment can include an apparatus and a method that can include a transceiver 2170 for receiving a higher layer message from a base station, the higher layer message for monitoring a sPDCCH control channel using DMRS within a plurality of sTTIs in a subframe, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI; and attempting to decode the sPDCCH using DMRS within a first sTTI, where at least one control symbol within the first sTTI can be excluded from overlapping with a CRS containing symbol. The apparatus and method can also include a controller 2120 for attempting to decode the sPDCCH using DMRS within a second sTTI using DM-RS REs present within the first sTTI, where at least one control symbol within the second sTTI can at least partially overlap with a CRS containing symbol, and the second sTTI can be adjacent to the first sTTI. The apparatus can be a UE 110 and the method can be performed by the UE 110. In an example, a DMRS based sPDCCH can occur within a sTTI "n" that includes a CRS or within a sTTI where a control symbol overlaps with a CRS containing symbol based on DMRS only if the DMRS can be shared between sTTI "n-1" and sTTI "n" and is present in sTTI "n-1". In an example, the UE 110 can assume that no DM-RS can be transmitted for a sPDCCH candidate within sTTI n and can use DM-RS REs from sTTI n-1 for demodulation of a sPDCCH candidate within sTTI n. In an example, the UE 110 can use the same subcarriers for DM-RS within sTTI n-1 to attempt to decode the sPDCCH within sTTI n as if the DM-RS was transmitted on sTTI n. In an example, the DM-RS from sTTI n-1 can at least overlap in frequency with sREGs associated with the sPDCCH within sTTI n. If the UE 110 can be configured to monitor a DMRS based sPDCCH via the controller 2120, then the UE 110 can monitor the DMRS based sPDCCH within a sTTI that includes a CRS or within a sTTI where a control symbol overlaps with a CRS containing symbol, where it is assumed that the DMRS can be shared between a previous sTTI and a current sTTI. In this case, the AL or location of control can still be different between sTTIs that share the DMRS, but the control resources of the second sTTI can fully overlap with the control and data of the first sTTI that contains the DMRS. In an example, the second sTTI can follow the first sTTI.

[0137] In a possible embodiment, for example, the transceiver 2170 can receive, from a base station, a higher layer message for monitoring a control channel candidate within at least one sTTI in a subframe and monitoring a set of RBs corresponding to the control channel candidate within the at least one sTTI, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI. The controller 2120 can determine, from the base station, a higher layer message for monitoring a control channel candidate within at least one sTTI in a subframe and monitoring a set of RBs corresponding to the control channel candidate within the at least one sTTI, where the higher layer can be higher than a physical layer, and where the sTTI can be shorter than a subframe length TTI; and determine control resource REs for transmission of the control channel candidate based on determining whether at least one RB in the set of RBs at least partially overlaps in frequency with a broadcast control channel or signal. The controller 2120 can attempt to decode the control channel candidate within the at least one sTTI according to the determined control resource REs, where the control channel candidate comprises an sCCE that spans a set of sREGs in a frequency domain, and the set of shortened resource element groups comprises the determined control resource elements.

[0138] According to a possible embodiment, the controller 2170 can map control information to the control resource REs for transmission of the control channel candidate using a first mapping if at least one RB in the set of RBs at least partially overlaps in frequency with a broadcast control channel or signal; and map control information to the control resource REs for transmission of the control channel candidate using a second mapping if none of the RBs in the set of RBs overlap in frequency with a broadcast control channel or signal, where the first mapping and the second mapping can be different. A second set of sCCEs can be a subset of a first set of sCCEs.

[0139] In an example, the controller 2170 can exclude control information from being mapped to at least one RB in the set of RBs that at least partially overlaps in frequency with a broadcast control channel or signal. In an example, if the at least one RB in the set of RBs that at least partially overlaps in frequency with a broadcast control channel or signal belongs to a second set of RBs, the control information can be excluded from being mapped to the second set of RBs, where the second set of RBs can be a subset of the set of RBs. In an example, the second set of RBs can form a resource block group (RBG), where the RBG can be a unit of scheduling a downlink data transmission. In an example, the RBG size can be greater than 6 RBs.

[0140] According to possible embodiments, the set of sREGs of the sCCE can be a first set of sREGs if at least one of the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, and the set of sREGs of the sCCE can be a second set of sREGs if none of the set of RBs overlap in frequency with the broadcast control channel or signal. In an example, the first set of sREGs and the second set of sREGs can be different. In an example, the first set of sREGs can be a subset of the second set of sREGs.

[0141] According to possible embodiments, the control channel candidate can include a set of sCCEs, and the set of sCCEs can be a first set of sCCEs if at least one of the set of RBs at least partially overlaps in frequency with the broadcast control channel or signal, and the set of sCCEs can be a second set of sCCEs if none of the set of RBs overlap in frequency with the broadcast control channel or signal. In an example, the first set of sCCEs and the second set of sCCEs can be different. According to possible embodiments, the controller 2170 can also monitor the control channel using DMRS within at least the sTTI. In an example, the set of sREGs can use DMRS on the AP, where a precoder is applied to all DMRS REs in the set of sREGs. In possible embodiments, the at least one sTTI can include one of the first two sTTIs in the second slot of the subframe. In possible embodiments, the controller 2170 can exclude RBs containing a synchronization signal from being included in the mapping of control resources within sTTIs that overlap with the synchronization signal in time domain.

[0142] Further, another possible embodiment can include an apparatus and method that can include receiving a first higher layer message for monitoring a control channel candidate using CRS within at least one sTTI in a subframe, where the higher layer can be higher than a physical layer; and receiving a second higher layer message indicating whether the control channel candidate within the at least one sTTI can be mapped to a first set of DMRS REs in a control resource of the control channel candidate. The apparatus and method can also include attempting to decode the control channel candidate within the at least one sTTI using CRS based on the received second higher layer message when the control candidate is monitored. The apparatus can be a UE 110 and the method can be performed by the UE 110. For example, an sPDCCH within the at least one sTTI can be rate matched around data DMRS REs in sPDCCH control resources. In an example, the first set of DMRS REs can be associated with a downlink data transmission mode configured for the UE 110. In an example, the apparatus and method can also include receiving a third higher layer message indicating a number of control symbols for the control channel candidate using CRS and indicating a location of at least one control symbol within the at least one sTTI. In an example, the at least one sTTI includes one or more symbols containing CRS, and a location of control symbols of the sPDCCH within the at least one sTTI can be different from a location of the at least one symbol containing CRS. In an example, a third sREG in the first set of sREGs (sCCE1) occupies a third set of REs in a given RB in a first OFDM symbol, such as REs in RB1, sym 0, illustrated in FIG. 13, and the first control candidate can be excluded from occupying REs in the given RB in a second OFDM symbol except for DMRS REs associated with the third sREG. In an example, the first OFDM symbol and the DMRS REs in the second OFDM symbol associated with the third sREG can be determined based at least on frequency locations of DMRS REs corresponding to a downlink data transmission of the downlink data transmission mode. Figure 12

[0143] The methods of the present disclosure can be implemented on a programmed processor. However, the controller, flow charts, and modules can also be implemented on a general purpose computer, a special purpose computer, a programmed microprocessor, or microprocessor and peripheral integrated circuit elements, an integrated circuit, a hard-wired electronic, or logic circuit such as a discrete element circuit, a Programmable Logic Device or the like. In general, a machine that can be programmed to operate in accordance with the methods described herein is also considered a processor. Typically, a processor will receive instructions from a memory or like device, read the instructions, decompress the instructions as needed, and execute them in order to operate in accordance with the resulting program. Clearly, a processor that has subcomponents such as a central processing unit (CPU) 130 and memory 132 is a machine because it is capable of being programmed. Specifically, the CPU 130 is the typical processor used in a computer or similar device that executes instructions from programs that are stored, either permanently or temporarily, in a storage area such as memory 132, a disk drive (not shown), or similar device.

[0144] ​While the present disclosure has been described with respect to specific examples, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. For example, in other embodiments, various elements of the embodiments can be interchanged, added, or removed. Also, all elements of each schematic diagram are not necessarily essential to the operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure with the mere addition of elements from the independent claims. Accordingly, the embodiments of the present disclosure as set forth herein are intended to be illustrative, not limiting. Various changes can be made without departing from the spirit and scope of the present disclosure.

[0145] In this document, relational terms such as“first,”“second,” and the like can be used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The phrase“and / or” is defined as including at least one of the listed elements, options, or combinations thereof, but not necessarily all of the elements or options. The terms“comprises,”“comprising,”“including,” or“including” or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by“a” or“an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Furthermore, the term“another” is defined as at least a second or more. The terms“including,”“having,” and the like as used herein are defined as“comprising.” Furthermore, the Background section is written as inventor’s understanding of the background of some embodiments at the time of filing and includes inventor’s own recognition of problems in the prior art and / or problems encountered by the inventor in his work.

Claims

1. An apparatus, the apparatus comprising: A transceiver is configured to receive higher-layer messages from a base station, the higher-layer messages being configured to monitor control channel candidates within at least one shortened transmission time interval in a subframe and to monitor a set of resource blocks corresponding to the control channel candidates within the at least one shortened transmission time interval, wherein the higher layer is higher than the physical layer, and wherein the shortened transmission time interval is shorter than the subframe length transmission time interval. A controller is configured to determine whether at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal; based on the determination that the at least one resource block in the resource block set at least partially overlaps with the broadcast control channel or signal, determine control resource elements for transmitting control channel candidates; and attempt to decode the control channel candidates within the at least one shortened transmission time interval according to the determined control resource elements. The control channel candidate includes shortened control channel elements, and the shortened control channel element comprises a set of shortened resource element groups across the frequency domain. The set of shortened resource element groups includes the determined control resource elements. in: If at least one resource block in the resource block set at least partially overlaps in frequency with a broadcast control channel or signal, the controller uses a first mapping to map control information to control resource elements for transmitting the control channel candidate; and If no resource block in the set of resource blocks overlaps with a broadcast control channel or signal in frequency, the controller uses a second mapping to map control information to control resource elements for transmitting the control channel candidate. The first mapping and the second mapping are different.

2. The device according to claim 1, wherein, The control information is not mapped to at least one resource block in the resource block set that at least partially overlaps with the broadcast control channel or signal.

3. The device according to claim 1, wherein, The resource block set is a first resource block set, wherein if at least one resource block in the first resource block set that at least partially overlaps with the broadcast control channel or signal belongs to a second resource block set, the control information is not mapped to the second resource block set, wherein the second resource block set is a subset of the first resource block set.

4. The device according to claim 3, wherein, The second set of resource blocks forms a resource block group, wherein the resource block group is a unit for scheduling downlink data transmission, and optionally, the size of the resource block group is greater than 6 resource blocks.

5. The device according to claim 1, wherein, If at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal in frequency, then the set of shortened resource element groups of the shortened control channel element is a first set of shortened resource element groups; and if no resource block in the resource block set overlaps with a broadcast control channel or signal in frequency, then the set of shortened resource element groups of the shortened control channel element is a second set of shortened resource element groups, wherein the first set of shortened resource element groups and the second set of shortened resource element groups are different, and optionally wherein the first set of shortened resource element groups is a subset of the second set of shortened resource element groups.

6. The device according to claim 1, wherein, The control channel candidate includes a set of shortened control channel elements, and if at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal in frequency, the set of shortened control channel elements is a first set of shortened control channel elements, and if no resource block in the resource block set overlaps with a broadcast control channel or signal in frequency, the set of shortened control channel elements is a second set of shortened control channel elements, wherein the first set of shortened control channel elements and the second set of shortened control channel elements are different.

7. The device according to claim 6, wherein, The second set of shortened control channel elements is a subset of the first set of shortened control channel elements.

8. The device according to claim 1, wherein: The controller further uses a demodulation reference signal to monitor the control channel during the at least one shortened transmission time interval; as well as Wherein, at least a subset of the set of shortened resource element groups uses demodulation reference signals on the antenna port, wherein a single-layer precoder is applied to all demodulation reference signal resource elements in the at least subset of the set of shortened resource element groups.

9. The device according to claim 1, wherein, The at least one shortened transmission time interval includes one of the first two shortened transmission time intervals in the second time slot of the subframe.

10. The device according to claim 1, wherein, During a shortened transmission time interval that overlaps with a synchronization signal in the time domain, resource blocks containing the synchronization signal are not included in the mapping of control resources.

11. The device according to claim 1, wherein, At least one resource block in the resource block set includes a synchronization signal, and the resource element in the at least one resource block in the resource block set is not used to determine the control resource element of the control channel candidate within the at least one shortened transmission time interval that overlaps with the synchronization signal in the time domain.

12. A method, the method comprising: Receives higher-layer messages from a base station, the higher-layer messages being used to monitor control channel candidates within at least one shortened transmission time interval in a subframe and to monitor resource block sets corresponding to control channel candidates within the at least one shortened transmission time interval, wherein the higher layer is higher than the physical layer, and wherein the shortened transmission time interval is shorter than the subframe length transmission time interval. Determine whether at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal; Based on determining whether at least one resource block in the resource block set at least partially overlaps with the broadcast control channel or signal, control resource elements for transmitting control channel candidates are determined; and An attempt is made to decode the control channel candidate within the at least one shortened transmission time interval based on the determined control resource elements. The control channel candidate includes shortened control channel elements, and the shortened control channel element comprises a set of shortened resource element groups across the frequency domain. The set of shortened resource element groups includes the determined control resource elements. in: If at least one resource block in the resource block set at least partially overlaps in frequency with a broadcast control channel or signal, then a first mapping is used to map control information to control resource elements for transmitting the control channel candidate; and If no resource block in the set of resource blocks overlaps with a broadcast control channel or signal in frequency, then a second mapping is used to map the control information to control resource elements for transmitting the control channel candidate. The first mapping and the second mapping are different.

13. An apparatus, said apparatus comprising: A transceiver, configured to transmit higher-layer messages from a base station, the higher-layer messages being configured to monitor control channel candidates and resource block sets corresponding to control channel candidates within at least one shortened transmission time interval in a subframe, wherein the higher layer is above the physical layer, and wherein the shortened transmission time interval is shorter than a subframe-length transmission time interval; and A controller is configured to determine whether at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal, and based on the determination that at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal in frequency, determine control resource elements for candidates for a transmission control channel. The transceiver further transmits the control channel candidate within the at least one shortened transmission time interval according to the determined control resources, wherein the control channel candidate comprises shortened control channel elements comprising a set of shortened resource element groups across the frequency domain. in: If at least one resource block in the resource block set at least partially overlaps in frequency with a broadcast control channel or signal, the controller uses a first mapping to map control information to control resource elements for transmitting the control channel candidate; and If no resource block in the set of resource blocks overlaps with a broadcast control channel or signal in frequency, the controller uses a second mapping to map control information to control resource elements for transmitting the control channel candidate. The first mapping and the second mapping are different.

14. A method comprising: Higher-layer messages are transmitted from the base station for monitoring control channel candidates and resource block sets corresponding to control channel candidates within at least one shortened transmission time interval in a subframe, wherein the higher layer is higher than the physical layer, and wherein the shortened transmission time interval is shorter than the subframe length transmission time interval. Determine whether at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal; Based on determining whether at least one resource block in the resource block set at least partially overlaps with a broadcast control channel or signal in frequency, control resource elements for candidate transmission control channels are determined; and The control channel candidate is transmitted within the at least one shortened transmission time interval according to the determined control resources, wherein the control channel candidate comprises shortened control channel elements comprising a set of shortened resource element groups across the frequency domain. in: If at least one resource block in the resource block set at least partially overlaps in frequency with a broadcast control channel or signal, then a first mapping is used to map control information to control resource elements for transmitting the control channel candidate; and If no resource block in the set of resource blocks overlaps with a broadcast control channel or signal in frequency, then a second mapping is used to map the control information to control resource elements for transmitting the control channel candidate. The first mapping and the second mapping are different.

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