WO2017048324A1 - Low latency lte-a transmission using shortened tti and zero power csi-rs resources - Google Patents

Abstract

Latency for the wireless interface in a Long Term Evolution (LTE) system may be reduced by reducing the Transmission Time Interval (TTI) of communications. Zero Power (ZP) Channel State Information Reference Signals (CSI-RS) (ZP CSI-RS) may be scheduled for User Equipments (UE). UEs using the shortened TTI communications may use the ZP CSI-RS blocks to receive transmissions. That is, a base station may indicate to a UE, that is using a shortened TTI, to ignore the standard meaning of certain of the ZP CSI-RS blocks and to instead decode data during these resource elements.

Description

LOW LATENCY LTE-A TRANSMISSION USING

SHORTENED TTI AND ZERO POWER CSI-RS RESOURCES

RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Patent Application No. 62/218,708, which was filed on September 15, 2015, the contents of which are hereby incorporated by reference as though fully set forth herein.

BACKGROUND

Low latency is a key requirement in the development of Long Term Evolution (LTE) cellular systems. For instance, for some data transmission protocols, low latency over the wireless interface is critical to realizing higher data rates. Additionally, carrier-aggregation techniques, which involve aggregating data transmitted over multiple carriers, may benefit from low latency transmissions. In addition, lower latency over the wireless interface may enable support for new applications. For example, applications such as traffic safety/control and control of critical infrastructure and industry processes may require very low latency. Thus, it can be important to minimize or decrease latency over the wireless interface.

Examples of technologies considered, in the Third Generation Partnership Project (3GPP) LTE- Advanced (LTE-A) project, to reduce latency in the wireless interface, include instant uplink access, Transmission-Time Interval (TTI) shortening, and reduced processing time in terminals and base stations. TTI shortening, in particular, may refer to the technique in which the transmission time, for a particular unit of data (e.g., a frame), is decreased. By shortening the time required to transmit a frame over the wireless interface, latency may be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments described herein will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals may designate like structural elements. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

Fig. 1 is a diagram of an example environment in which systems and/or methods described herein may be implemented;

Fig. 2 is a diagram conceptually illustrating the multiplexing of shortened and non- shortened TTI transmissions;

Fig. 3 is a diagram conceptually illustrating a Physical Downlink Shared Channel (PDSCH) sub-frame, including potential Zero Power (ZP) Channel State Information Reference Signals (CSI-RS) (ZP CSI-RS) configurations; Fig. 4 is a flowchart illustrating a process for receiving data using shorter TTI transmissions;

Fig. 5 is a flowchart illustrating a process for transmitting data using shorter TTI transmissions;

Fig. 6 is a diagram conceptually illustrating a PDSCH sub-frame, including potential ZP CSI-RS configurations, consistent with one embodiment;

Fig. 7 is a flowchart illustrating a process for communicating indications of ZP CSI-RS blocks for shorter TTI transmissions;

Fig. 8 is a flowchart illustrating a process for determining the Transmit Block Size (TBS) when using shorter TTI communications; and

Fig. 9 illustrates example components of an electronic device.

DETAILED DESCRIPTION OF PREFERRED EMBODFMENTS

The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.

Techniques described herein relate to techniques for reducing the TTI in the Physical Downlink Shared Channel (PDSCH) of an LTE-A cellular system. One issue that may be encountered when reducing the TTI of a frame or sub-frame is that the TTI shortened transmission may still need to coexist with non-shortened transmissions (e.g., called "legacy" or "normal" transmissions herein). For instance, shortening the TTI of a resource element (RE) may require that additional frequency bandwidth be used for the transmission. The additional bandwidth may cause interference between the TTI shortened transmissions in the legacy transmissions, potentially leading to errors and/or suboptimal communication efficiency.

Consistent with aspects described herein, Zero Power (ZP) Channel State Information Reference Signals (CSI-RS) (ZP CSI-RS) REs may be scheduled for the User Equipments (UEs) in one or more cells. Legacy UEs may interpret the ZP CSI-RS resource elements as standard ZP CSI-RS resource elements that are not used for transmission or reception. Non-legacy UEs, however, may be further configured to use certain of the ZP CSI-RS resource elements to receive transmissions. That is, a base station may indicate to a UE, that is using TTI shortening, to ignore the standard meaning of certain of the ZP CSI-RS resource elements, and to instead receive, via PDSCH, data. Additionally, techniques for determining the TBS, when using TTI shortening, are also described herein.

Fig. 1 is a diagram of an example environment 100 in which systems and/or methods described herein may be implemented. As illustrated, environment 100 may include UE 110, which may obtain network connectivity from wireless network 120. Although a single UE 110 is shown, for simplicity, in Fig. 1, in practice, multiple UEs 110 may operate in the context of a wireless network. Wireless network 120 may provide access to one or more external networks, such as packet data network (PDN) 150. The wireless network may include radio access network (RAN) 130 and core network 140. RAN 130 may be an E-UTRA based radio access network or another type of radio access network. Some or all of RAN 130 may be associated with a network operator that controls or otherwise manages core network 140. Core network 140 may include an Internet Protocol (IP)-based network.

UE 110 may include a portable computing and communication device, such as a personal digital assistant (PDA), a smart phone, a cellular phone, a laptop computer with connectivity to a cellular wireless network, a tablet computer, etc. UE 110 may also include non-portable computing devices, such as desktop computers, consumer or business appliances, or other devices that have the ability to wirelessly connect to RAN 130.

RAN 130 may represent a 3 GPP access network that includes one or more RATs. RAN 130 may particularly include multiple base stations, referred to as eNBs 136. eNBs 136 may include eNBs that provide coverage to a relatively large (macro cell) area or a relatively small (small cell) area. Small cells may be deployed to increase system capacity by including a coverage area within a macro cell. Small cells may include, for example, picocells, femtocells, and/or home NodeBs. Small cells may, in some situations, be operated as Secondary Cells (SCells), in which the macro cell (called the Primary Cell (PCell)) may be used to exchange important control information and provide robust data coverage and the SCell may be used as a secondary communication channel, such as to offload downlink data transmissions. eNBs 136 can potentially include remote radio heads (RRHs). RRHs can extend the coverage of an eNB by distributing the antenna system of the eNB.

In the 3 GPP network architecture, core network 140 may include an Evolved Packet Core (EPC). As illustrated, core network 140 may include serving gateway (SGW) 142, Mobility Management Entity (MME) 144, and packet data network gateway (PGW) 146.

Although certain network devices are illustrated in environment 100 as being part of RAN 130 and core network 140, whether a network device is labeled as being in the "RAN" or the "core network" of environment 100 may be an arbitrary decision that may not affect the operation of wireless network 120. SGW 142 may include one or more network devices that aggregate traffic received from one or more e Bs 136. SGW 142 may generally handle user (data) plane traffic. MME 144 may include one or more computation and communication devices that perform operations to register UE 110 with core network 140, establish bearer channels associated with a session with UE 110, hand off UE 110 from one eNB to another, and/or perform other operations. MME 144 may generally handle control plane traffic.

PGW 146 may include one or more devices that act as the point of interconnect between core network 140 and external IP networks, such as PDN 150, and/or operator IP services. PGW 146 may route packets to and from the access networks, and the external IP networks.

PDN 150 may include one or more packet-based networks. PDN 150 may include one or more external networks, such as a public network (e.g., the Internet) or proprietary networks that provide services that are provided by the operator of core network 140 (e.g., IP multimedia (FMS)-based services, transparent end-to-end packet-switched streaming services (PSSs), or other services).

A number of interfaces are illustrated in Fig. 1. An interface may refer to a physical or logical connection between devices in environment 100. The illustrated interfaces may be 3GPP standardized interfaces. For example, as illustrated, eNBs 136 may communicate with SGW 142 and MME 144 using the SI interface (e.g., as defined by the 3 GPP standards). eNBs 136 may communicate with one another via the X2 interface.

The quantity of devices and/or networks, illustrated in Fig. 1, is provided for explanatory purposes only. In practice, there may be additional devices and/or networks; fewer devices and/or networks; different devices and/or networks; or differently arranged devices and/or networks than illustrated in Fig. 1. Alternatively, or additionally, one or more of the devices of environment 100 may perform one or more functions described as being performed by another one or more of the devices of environment 100. Furthermore, while "direct" connections are shown in Fig. 1, these connections should be interpreted as logical communication pathways, and in practice, one or more intervening devices (e.g., routers, gateways, modems, switches, hubs, etc.) may be present.

As previously mentioned, in order to reduce latency in the wireless interface (i.e., the interface between eNBs 136 and UE 110), TTI shortening may be used. For example, the number of symbols used in a sub-frame may be shortened to 7, 2, or even 1 symbol (e.g., from

14 legacy symbols). Multiplexing of the conventional (non-shortened TTI) resource allocation and the resource allocation with shortened TTI may be used to enable both shortened and legacy

UE operation in the wireless interface.

Fig. 2 is a diagram conceptually illustrating the multiplexing of shortened and non- shortened (legacy) TTI transmissions. The conventional approach of supporting such coexistence relies on the puncturing of the legacy PDSCH or FDM multiplexing.

As shown in Fig. 2, data may be transmitted in legacy TTI resource blocks 205 and shortened TTI resource blocks 210. The resource blocks 210 may use a shorter transmission period to thus decrease latency relative to the use of resource blocks 205. In some situations, however, in order to operate in the shorter time periods, resource blocks 210 may be

implemented to use additional system bandwidth. As shown in Fig. 2, each resource block 210 may use more bandwidth than each resource block 205. This can be particularly troublesome for coexistence of resource blocks 205 and 210, as resource blocks 210 can cause interference (frequency-wise) with resource blocks 205 by "puncturing" the frequency spectrum of resource blocks 205.

In Release 10 of the 3GPP standard, ZP CSI-RS resources were introduced. CSI-RS signals may be used to allow UEs to measure properties of the radio channel. ZP CSI-RS resources may be used avoid interference on the non -zero-power (NZP) CSI-RS resources of neighboring cells. In other words, conventionally, ZP CSI-RS resources prevent the PDSCH from being mapped to a set of REs. Thus, ZP CSI-RS may be used to mute REs within a cell to improve the operation of neighboring cells.

The ZP CSI-RS configuration (i.e., which REs are mapped to ZP CSI-RS) may be provided to UEs using higher layer signaling. For example, information describing the ZP CSI- RS configuration may be exchanged, between UE 110 and e B 136, using Radio Resource Control (RRC) protocol sublayer signaling. The RRC layer is defined, in the 3 GPP standards, as part of the LTE control plane for the air interface.

Information describing the ZP CSI-RS configuration (e.g., received at the UE via higher layer signaling) may include information describing the periodicity of the ZP CSI-RS blocks

(e.g. every 5, 10, etc. sub-frames), information describing sub-frame offset value(s) (e.g., zero

... periodicity in sub-frame-1), and a resource bitmap indicating the activated ZP CSI-RS resources (i.e., the particular REs that are to be used for a given configuration). For a given ZP

CSI-RS configuration, UEs perform PDSCH reception assuming no transmission of the PDSCH on the corresponding ZP CSI-RS resource elements. In Release 11 of the 3GPP standard, the ZP

CSI-RS resource elements were further enhanced to provide up to four different potential ZP

CSI-RS configurations. The potential different ZP CSI-RS blocks may be configured, at UE

110, through higher layer signaling (e.g., RRC layer signaling) with eNB 136. Each potential

ZP CSI-RS configuration may also be associated with one or more PDSCH resource element mapping sets (e.g., via a resource bit) which may also be configured, at the UE, using higher layer (e.g., RRC layer) control signaling. The actual PDSCH resource element mapping set to use may be indicated using a bit, from a bit-field mapping, in the Downlink Control Information (DCI) signal.

The DCI signal may be transmitted, to UE 110, as part of the Physical Downlink Control Channel (PDCCH). The DCI signal may generally provide a mapping indicating, to UE 110, how the UE is to decode and obtain the data, for the UE, in the PDSCH in the same sub- frame. Thus, the DCI signal, transmitted in the PDCCH, may act as a map through which the UE may find and decode the UE's data from the PDSCH. The DCI signal may include information such as the number of resource blocks, resource allocation type, modulation scheme, transport block, redundancy version, coding rate etc. Upon reception of the DCI signal, UE 110 may demodulate the PDSCH in accordance to the indicated PDSCH REs mapping set.

Fig. 3 is a diagram conceptually illustrating a PDSCH sub-frame, including potential ZP CSI-RS configurations. As shown in Fig. 3, a sub-frame 300, which may correspond to a 1ms transmission interval, may include 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols (labeled as 0 through 13, on the horizontal axis). Each OFDM symbol may correspond to a RE and may represent the smallest discrete part of a frame/sub-frame. In various LTE implementations, a symbol may represent 2, 4, 6, or 8 bits per symbol. The vertical axis of sub- frame 300 may be divided into a number of OFDM sub-carriers. For example, each sub-carrier may have a bandwidth of 15 kHz or 7.5 kHz. Twelve sub-carriers of one resource block are shown in Fig. 3.

Various REs in sub-frame 300 may be allocated to different control and data signals. For instance, as shown, certain REs are Cell-specific Reference Signals (CRS) REs, control region REs, Demodulation Reference Signal (DMRS) REs, or PDSCH data REs. Additionally, some of the REs may potentially be REs used for ZP CSI-RS blocks. Eight potentially independently addressable ZP CSI-RS blocks are illustrated in sub-frame 300 and are labeled as ZP CSI-RS-0 through ZP CSI-RS-9. Each potential ZP CSI-RS block occupies two consecutive REs (i.e., two OFDM symbols). For a given sub-frame 300, which of the potential ZP CSI-RS blocks that are actually allocated may be signaled, by e B 136, via the bitmap that is transmitted using higher layer (e.g., RRC layer) control signaling. For example, in the example of Fig. 3, because ten different possible ZP CSI-RS blocks are defined, the bitmap may be a ten bit bitmap, in which the first bit may correspond to ZP CSI-RS-0, the second bit may correspond to ZP CSI-RS-1, and the last bit may correspond to ZP CSI-RS-9. Thus, for example, if the first bit and the last bit are set, only the ZP CSI-RS-0 and ZP CSI-RS-9 may be configured to be active. The other ZP CSI-RS blocks that are illustrated in sub-frame 300 may instead be used for, for example, PDSCH data. In this manner, eNB 136 can flexibly control which REs are used as the ZP CSI- RS blocks. Fig. 4 is a flowchart illustrating a process 400 for receiving data using shorter TTI transmissions. Process 400 may be performed by, for example, a UE 110 that is configured to receive shorter TTI transmissions.

Process 400 may include receiving/decoding, via RRC signaling with an eNB, potential ZP CSI-RS configurations (block 410). As mentioned, UE 110 may receive, via higher layer signaling (e.g., RRC signaling), information relating to possible ZP CSI-RS configurations. Information describing each ZP CSI-RS configuration may include, for example, information describing the periodicity of ZP CSI-RS transmission (e.g. every 5, 10, etc. sub-frames), information describing sub-frame offset value(s) (e.g., zero ... periodicity in sub-frame-1), and/or a resource bitmap indicating the activated ZP CSI-RS resources. The potential ZP CSI- RS configuration information, as received in block 410, may occur relatively infrequently (e.g., at initial attachment of the UE a cell, etc.). In some implementations, the decoding of the ZP CSI RS configurations may be performed via baseband circuitry at the UE.

Process 400 may further include obtaining, from the DCI signal (e.g., transmitted as part of the PDCCH), the actual ZP CSI-RS configuration that is to be used (block 420). For example, part of the DCI, for a UE, may contain a bitmap that indicates which of the REs, of a sub-frame, are ZP CSI-RS blocks. For example, with reference to Fig. 3, the DCI bitmap may indicate that ZP CSI-RS blocks ZP CSI-RS-0 and ZP CSI-RS-1 are active. UE 110 may thus process the bitmap to decode the actual ZP CSI-RS configuration.

The operations performed in blocks 410 and 420 may apply to all UEs 110 in a cell. That is, UEs that are performing only legacy TTI communications (e.g., UEs that are not capable or not configured to handing the shorter TTI transmissions) may also receive the ZP CSI-RS block information. For these UEs, the ZP CSI-RS blocks will function as conventional ZP CSI- RS blocks.

Process 400 may further include obtaining (e.g., decoding), from the DCI signal, the indication of the shorter TTI transmissions, in the PDSCH, that apply to the particular UE (block 430). As previously mentioned, the DCI may act as a map for UEs to decode the particular symbols, that apply to the UE, from the PDSCH. For a particular UE capable of shorter TTI transmissions, at least some of the REs, indicated in the DCI, may be REs that correspond to ZP CSI-RS REs. In one implementation, the shorter TTI transmissions may be fully scheduled to overlap with ZP CSI-RS blocks.

Process 400 may further include receiving/decoding data, from the PDSCH, using the shorter TTI transmissions (block 440). That is, based on the DCI signal, the UE may decode the shorter TTI PDSCH resource elements that are relevant to the UE. For example, a shorter TTI communication may correspond to a sub-frame that is only two symbols long. In some implementations, the RE for a shorter TTI communication may use differently defined sub- carriers. For example, each symbol may be transmitted with a larger bandwidth than a corresponding legacy transmission. Consistent with aspects described herein, the shorter TTI transmissions may be partially or wholly scheduled, by eNB 136, to overlap with ZP CSI-RS blocks. Because substantive data transmissions, for legacy TTI transmissions, are not made in the ZP CSI-RS blocks, overlap between the shorter TTI transmissions in the legacy TTI transmission may be minimized. ENB 136, by scheduling ZP CSI-RS blocks to be coincident with the shorter TTI transmissions, may minimize interference between the shorter TTI transmissions and legacy TTI transmissions.

UEs configured for shorter TTI communications may also perform legacy TTI communications. Process 400 may further include receiving/decoding, via DCI signaling, the indications of PDSCH transmissions, using legacy TTI, that apply to the UE (block 450). Based on the DCI signaling, the UE may thus receive data, in the PDSCH, using the legacy TTI (block 460).

Fig. 5 is a flowchart illustrating a process 500 for transmitting data using shorter TTI transmissions. Process 500 may be performed by, for example, eNB 136.

Process 500 may include determining and transmitting, via RRC signaling with UEs 110, potential ZP CSI-RS configurations (block 510). The potential ZP CSI-RS configurations may be statically configured at the eNB (e.g., during initial setup of the eNB by an technician) or dynamically determined by eNB 136.

Process 500 may further include generating and transmitting, via the DCI, the actual ZP CSI-RS configuration that is to be used by the UEs (block 520). In some implementations, eNB 136 may generate the particular ZP CSI-RS configuration to use based on one or more factors, such as, the current load of a cell, the portion of UEs in the cell that are capable of receiving shorter TTI communications, or other factors. The actual ZP CSI-RS configuration may be transmitted, to the UEs, as a bitmap.

Process 500 may further include generating and transmitting, via the DCI, the indications of the shorter TTI transmissions, in the PDSCH, that apply to particular UEs (block 530). That is, eNB 136 may construct the DCI to inform each UE how to obtain data (decode) from the PDSCH. For UEs capable of shorter TTI transmission, the UEs may be instructed to decode the PDSCH at resource elements that were previously indicated as corresponding to ZP CSI-RS blocks.

Process 500 may further include transmitting data, via PDSCH and to the UEs, using the shorter TTI transmissions (block 540). As previously mentioned, the shorter TTI transmissions may be partially or wholly scheduled, by eNB 136, to overlap with ZP CSI-RS blocks. Because substantive data transmissions, for legacy TTI transmissions, are not made in the ZP CSI-RS blocks, interference between the shorter TTI transmissions in the legacy TTI transmission may therefore be minimized.

E Bs 136 may also communicate with UEs 110 using legacy TTI communications. Process 500 may further include generating and transmitting, via the DCI, the indications of PDSCH transmissions, using legacy TTI, that apply to the UEs (block 550). Based on the DCI signaling, the UEs may thus receive data, in the PDSCH, using the legacy TTI. E B 136 may correspondingly transmit data to the UEs using the legacy TTI transmissions (block 560).

In the above discussion, the ZP CSI-RS blocks were described as ZP CSI-RS blocks that were located in the sub-frame at positions defined based on the 3 GPP Release 10 and 11 standard. Alternatively, in some implementations, additional potential ZP CSI-RS locations may be defined in a sub-frame. The additional ZP CSI-RS locations may give the e B additional flexibility in scheduling shorter TTI communications.

Fig. 6 is a diagram conceptually illustrating a PDSCH sub-frame, including potential ZP CSI-RS configurations, consistent with one embodiment. Sub-frame 600, shown in Fig. 6, may be constructed similarly to sub-frame 300, but may include additional potential resource elements that may be assigned as ZP CSI-RS blocks. In particular, 12 potential ZP CSI-RS blocks are illustrated in sub-frame 600 and are labeled as ZP CSI-RS-0 through ZP CSI-RS-11. Each potential ZP CSI-RS block occupies two consecutive REs (i.e., two symbols). For a given sub-frame 600, which of the potential ZP CSI-RS that are actually allocated may be signaled, by eNB 136, via the bitmap that is transmitted using higher layer (e.g., RRC layer) control signaling. For example, in the example of Fig. 6, because 12 different possible ZP CSI-RS blocks are defined, the bitmap may be a 12 bit bitmap, in which the first bit may correspond to ZP CSI-RS-0, the second bit may correspond to ZP CSI-RS-1, and the last bit may correspond to ZP CSI-RS-11. Thus, for example, if the first bit and the last bit are set, only ZP CSI-RS-0 and ZP CSI-RS-11 may be configured to be active. The other ZP CSI-RS blocks that are illustrated in sub-frame 600 may instead be used for, for example, PDSCH data. In this manner, eNB 136 can flexibly control which REs are used as the ZP CSI-RS blocks.

Relative to sub-frame 300, in sub-frame 600, additional ZP CSI-RS resources are introduced in the third and fourth (indexes 2 and 3 in Fig. 3) OFDM symbols of the sub-frame, and also in the sixth and seventh (indexes 5 and 6) and the 13^th and 14^th (indexes 12 and 13) OFDM symbols.

In some implementations, for LTE Transmission Mode 10, the mapping of the PDSCH

REs for UEs may be enhanced by configuring ZP CSI-RS blocks for each PDSCH RE mapping and Quasi-Co-Location (QCL) parameter (QCL) set. In this case, the time domain presence of the ZP CSI-RS blocks may be indicated using DCI scheduling of the PDSCH (e.g., on one or more corresponding sub-frames on the PDSCH) instead of sub-frame periodicity and offset configuration of the corresponding ZP CSI-RS. In this implementation, eNB 136 may indicate, via aperiodic indication using DCI signaling, ZP CSI-RS blocks for UEs using legacy TTI to achieve co-existence and orthogonal multiplexing with UEs scheduled for PDSCH

communications using shortened TTI.

Fig. 7 is a flowchart illustrating a process 700 for communicating indications of ZP CSI- RS blocks for shorter TTI transmissions. Process 700 may be performed by, for example, eNB 136.

Process 700 may include determining ZP CSI-RS blocks for each PDSCH RE mapping and QCL parameter set (block 710). The ZP CSI-RS blocks may be used for shorter TTI transmissions. For example, for LTE Transmission Mode 10, eNB 136 may determine a number of ZP CSI-RS blocks, to use for shorter TTI transmissions, for a sub-frame.

Process 700 may further include transmitting indications of the determined ZP CSI-RS blocks, to the UEs, using DCI signaling in the PDSCH sub-frames (block 720). The UEs may extract the ZP CSI-RS block indications, and hence the REs to use for the shorter TTI transmissions, from the DCI signaling.

In LTE, the PDSCH carries data Transport Blocks (TBs) which correspond to a Media Access Control (MAC) Packet Data Unit (PDU). The size of the transport block may be variable and chosen based on several physical layer parameters such as modulation and coding schemes, and the resource allocation size. The procedure to determine the transport block size (TBS) may be based on the type of scheduling for the Radio Network Temporary Identifier (RNTI) (e.g. Cell-RNTI (C-RNTI), System Information-RNTI (SI-RNTI), etc.), type of the sub- frame, number of Multiple Input Multiple Output (MFMO) layers, etc. Conventionally, determining the size of the transport block may include providing the modulation and coding scheme and resource allocation size (NPRB) to the UE using DCI. Based on this information, the transport block size (TBS) index (ITBS) may be derived, by the UE, from a look-up operation, such as a look-up operation performed based on the tables given in the 3GPP Technical

Specification (TS) TS 36.213, section 7.1.7.1 (for downlink) or section 8.6.1 (for uplink). After determining ITBS and NPRB, another look-up operation may be performed, based on 3 GPP TS 36.213, section 7.1.7.2.1, which will determine the transport block size for the current sub- frame.

The TBS table in section 7.1.7.2.1 of 3GPP TS 36.213 was designed assuming 120 REs for PDSCH transmission. In some cases, the number of available resource elements may be different. In some embodiments, when using shortened TTIs, the TBS may be determined based on the actual number of available PDSCH REs within the allocation, denoted as NRE, instead of the resource allocation size, NPRB. In this situation, the effective resource allocation size NPRB' may be calculated as:

max(ceil {^ ) , l). (1)

Here, ceil indicates the ceiling function (i.e., the smallest integer not less than the argument), and max indicates the maximum function (i.e., the largest value of the arguments).

NPRB' may be used, when calculating the TBS pursuant to section 7.1.7.2.1 of 3GPP TS 36.213, in place of NPRB. Alternatively, the effective resource allocation size NPRB' can be calculated as:

max(cei ("^⁷") , 1); or (2) max(c_e// (^n) , l), (3) where TTI is the number of OFDM symbols in the shortened TTI.

Fig. 8 is a flowchart illustrating a process 800 for determining the TBS when using shorter TTI communications. Process 800 may be performed by, for example, UE 110.

Process 800 may include receiving an indication of a modulation coding scheme and resource allocation information (block 810). The modulation coding scheme and resource allocation information may be received, from eNB 136, via DCI signaling. As mentioned previously, the resource allocation information may be the actual number of available PDSCH REs within the allocation (NRE).

Process 800 may further include calculating the effective resource allocation size (block 820). The effective resource allocation size NPRB', may be calculated using, for example, expressions (1), (2), or (3), given above.

Process 800 may further include determining the transport blocks size based on the modulation and coding scheme and the effective resource allocation size (block 830). In one implementation, the transport block size may be determined based on a look-up operation based on section 7.1.7.1 (for downlink) or section 8.6.1 (for uplink) of 3GPP TS 36.213, in which NPRB' is used in place of NPRB.

As used herein, the term "circuitry" or "processing circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor

(shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware.

Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. Fig. 9 illustrates, for one embodiment, example components of an electronic device 900. In embodiments, the electronic device 900 may be a user equipment UE, an e B, a transmission point, or some other appropriate electronic device. In some embodiments, the electronic device 900 may include application circuitry 902, baseband circuitry 904, Radio Frequency (RF) circuitry 906, front-end module (FEM) circuitry 908 and one or more antennas 960, coupled together at least as shown. In other embodiments, any of said circuitries can be included in different devices.

Application circuitry 902 may include one or more application processors. For example, the application circuitry 902 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general- purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system. The memory/storage may include, for example, computer-readable medium 903, which may be a non-transitory computer-readable medium. Application circuitry 902 may, in some embodiments, connect to or include one or more sensors, such as environmental sensors, cameras, etc.

Baseband circuitry 904 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 904 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 906 and to generate baseband signals for a transmit signal path of the RF circuitry 906. Baseband processing circuitry 904 may interface with the application circuitry 902 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 906. For example, in some embodiments, the baseband circuitry

904 may include a second generation (2G) baseband processor 904a, third generation (3G) baseband processor 904b, fourth generation (4G) baseband processor 904c, and/or other baseband processor(s) 904d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 9G, etc.). The baseband circuitry 904 (e.g., one or more of baseband processors 904a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 906. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some implementations, the functionality of baseband circuitry 904 may be wholly or partially implemented by memory/storage devices configured to execute instructions stored in the memory/storage. The memory/storage may include, for example, a non-transitory computer-readable medium 904h.

In some embodiments, modulation/demodulation circuitry of the baseband circuitry 904 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 904 may include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments. In some embodiments, the baseband circuitry 904 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 904e of the baseband circuitry 904 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 904f. The audio DSP(s) 904f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments.

In some embodiments, the baseband circuitry 904 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 904e of the baseband circuitry 904 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 904f. The audio DSP(s) 104f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments.

Baseband circuitry 904 may further include memory/storage 904g. The memory/storage 904g may be used to load and store data and/or instructions for operations performed by the processors of the baseband circuitry 904. Memory/storage 904g may particularly include a non- transitory memory. Memory/storage for one embodiment may include any combination of suitable volatile memory and/or non-volatile memory. The memory/storage 904g may include any combination of various levels of memory/storage including, but not limited to, read-only memory (ROM) having embedded software instructions (e.g., firmware), random access memory (e.g., dynamic random access memory (DRAM)), cache, buffers, etc. The

memory/storage 904g may be shared among the various processors or dedicated to particular processors.

Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some

embodiments, some or all of the constituent components of the baseband circuitry 904 and the application circuitry 902 may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 904 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 904 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 904 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 906 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 906 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 906 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 908 and provide baseband signals to the baseband circuitry 904. RF circuitry 906 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 904 and provide RF output signals to the FEM circuitry 908 for transmission.

In some embodiments, the RF circuitry 906 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 906 may include mixer circuitry 906a, amplifier circuitry 906b and filter circuitry 906c. The transmit signal path of the RF circuitry 906 may include filter circuitry 906c and mixer circuitry 906a. RF circuitry 906 may also include synthesizer circuitry 906d for synthesizing a frequency for use by the mixer circuitry 906a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 906a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 908 based on the synthesized frequency provided by synthesizer circuitry 906d. The amplifier circuitry 906b may be configured to amplify the down-converted signals and the filter circuitry 906c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals.

Output baseband signals may be provided to the baseband circuitry 904 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 906a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In various embodiments, when the electronic device 900 is implemented as part of a user equipment (UE), the baseband circuitry 904 may be configured to determine based on communication with an evolved node B (eNB), a higher layer configuration of physical downlink control channel (PDSCH) resources with shortened time transmission interval (TTI), where in the PDSCH resources are subset of the ZP CSI-RS resources; and determine an indication of a PDSCH transmission with shortened TTI using the configured resources using the DCI. In such embodiments, RF circuitry 906 may provide for the communication with the eNB.

In other embodiments, when the electronic device 900 is implemented as part of a user equipment (UE), the radio frequency (RF) circuitry may be configured to receive an indication of a modulation and coding scheme (MCS) and a resource allocation from an eNB; and baseband circuitry 904 may be configured to calculate a number of available resources (NRE) within the resource allocation; and determine a TBS indication based on the MCS and the NRE within the resource allocation.

In other embodiments, when the electronic device 900 is implemented as part of a user equipment (UE), the baseband circuitry 904 may be configured to determine, based on a communication from an eNB, a configuration of ZP CSI-RS resources for a physical downlink shared channel (PDSCH) resource element (RE) mapping and quasi co-location (QCL) set without sub-frame and periodic ZP CSI-RS resource configuration; and determine an indication of the ZP CSI-RS presence using downlink control information (DCI) scheduling on one or more corresponding sub-frames on the PDSCH. In such embodiments, RF circuitry 906 may provide for the communication with the eNB.

In various embodiments, when the electronic device 900 is implemented as part of an eNB the baseband circuitry 904 may be configured to schedule ZP CSI-RS resources for a physical downlink shared channel (PDSCH) resource element (RE) mapping and quasi co- location (QCL) set without sub-frame and periodic ZP CSI-RS resource configuration; and generate a downlink control information (DCI) indication to indicate the ZP CSI-RS on one or more corresponding sub-frames on the PDSCH; and the RF circuitry 906 may provide the DCI message to a user equipment (UE).

In some embodiments, the mixer circuitry 906a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 906d to generate RF output signals for the FEM circuitry 908. The baseband signals may be provided by the baseband circuitry 904 and may be filtered by filter circuitry 906c. The filter circuitry 906c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 906a of the receive signal path and the mixer circuitry 906a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 906a of the receive signal path and the mixer circuitry 906a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 906a of the receive signal path and the mixer circuitry 906a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 906a of the receive signal path and the mixer circuitry 906a of the transmit signal path may be configured for super-heterodyne operation.

In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 906 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 904 may include a digital baseband interface to communicate with the RF circuitry 906.

In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry 906d may be a fractional-N synthesizer or a fractional N/N+6 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 906d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry 906d may be configured to synthesize an output frequency for use by the mixer circuitry 906a of the RF circuitry 906 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 906d may be a fractional N/N+6 synthesizer.

In some embodiments, frequency input may be provided by a voltage-controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 904 or the applications processor 902 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 902.

Synthesizer circuitry 906d of the RF circuitry 906 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+6 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry 906d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 906 may include an IQ/polar converter.

FEM circuitry 908 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 960, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 906 for further processing. FEM circuitry 908 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 906 for transmission by one or more of the one or more antennas 960.

In some embodiments, the FEM circuitry 908 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received

RF signals as an output (e.g., to the RF circuitry 906). The transmit signal path of the FEM circuitry 908 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 906), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 960.

In some embodiments, the electronic device 900 may include additional elements such as, for example, memory/storage, display, camera, sensors, and/or input/output (I/O) interface. In some embodiments, the electronic device of Fig. 9 may be configured to perform one or more methods, processes, and/or techniques such as those described herein.

A number of examples, relating to implementations of the techniques described above, will next be given.

In a first example, an apparatus for a baseband processor of a UE may include circuitry to: decode, based on information received via RRC signaling, configuration information for ZP CSI-RS blocks in PDSCH resources; decode, based on information received via DCI, an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks in the PDSCH resources; and decode data, for the UE, from the indicated ZP CSI-RS blocks. In example 2, the subject matter of example 1, or any of examples herein, may further include one or more antennas, wherein the DCI is transmitted as part of the PDCCH using the one or more antennas.

In example 3, the subject matter of example 1, or any of the examples herein, may further include wherein the configuration information includes a plurality of potential ZP CSI-RS configurations, and wherein the circuitry is further to: receive, via the DCI, an indication of one of the potential ZP CSI-RS configurations to use.

In a fourth example, an apparatus of for a baseband processor of an e B comprising circuitry to: generate, for transmission via RRC signaling to UE, configuration information for ZP CSI-RS blocks in PDSCH resources; generate, for transmission to the UE via DCI, an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks; and causing transmission of data, to the UE, using the indicated ZP CSI-RS blocks in the PDSCH.

In example 5, the subject matter of example 1 or 4 , or any of the examples herein, wherein the data transmissions in the ZP CSI-RS blocks are performed using a first TTI, and wherein the UE is capable of communicating using a second TTI that is longer than the first TTI, data for the second TTI being communicated, to the UE, using resource elements that do not overlap with the ZP CSI-RS blocks.

In example 6, the subject matter of example 5, or any of the examples herein, wherein the first TTI consists of two OFDM symbols. In example 7, the subject matter of example 5, or any of examples herein, wherein all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

In example 8, the subject matter of example 5, or any of the examples herein, wherein less than all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

In a ninth example, a computer readable medium containing program instructions for causing one or more processors, associated with UE, to: decode, based on information received via RRC signaling, configuration information for ZP CSI-RS blocks in PDSCH resources; decode, based on information received via DCI, an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks in the PDSCH resources; and decode data, for the UE, from the indicated ZP CSI-RS blocks.

In example 10, the subject matter of example 9, or any of the examples herein, wherein the DCI is transmitted as part of the PDCCH.

In example 11, the subject matter of example 9, or any of the examples herein, wherein the configuration information includes a plurality of potential ZP CSI-RS configurations, and wherein the computer readable medium further includes program instructions for causing the one or more processors to: receive, via the DCI, an indication of one of the potential ZP CSI-RS configurations to use.

In example 12, the subject matter of example 9, or any of the examples herein, wherein the data transmissions in the ZP CSI-RS blocks are performed using a first TTI, and wherein the UE is capable of communicating using a second TTI that is longer than the first TTI, data for the second TTI being communicated, to the UE, using resource elements that do not overlap with the ZP CSI-RS blocks.

In example 13, the subject matter of example 12, or any of the examples herein, wherein the first TTI consists of two OFDM symbols.

In example 14, the subject matter of example 12, or any of the examples herein, wherein all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

In example 15, the subject matter of example 12, or any of the examples herein wherein less than all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

In a 16^th example, a UE may comprise means for receiving, via RRC signaling, configuration information for ZP CSI-RS blocks in PDSCH resources; means for receiving, via DCI, an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks in the PDSCH resources; and means for decoding data, for the UE, from the indicated ZP CSI-RS blocks.

In example 17, the subject matter of claim 16, or any of the examples herein, wherein the DCI is transmitted as part of the PDCCH.

In example 18, the subject matter of example 16, or any of the examples herein, wherein the configuration information includes a plurality of potential ZP CSI-RS configurations, the UE further comprising: means for receiving, via the DCI, an indication of one of the potential ZP CSI- RS configurations to use.

In example 19, the subject matter of example 16, or any of the examples herein, wherein the data transmissions in the ZP CSI-RS blocks are performed using a first TTI, and wherein the UE is capable of communicating using a second TTI that is longer than the first TTI, data for the second TTI being communicated, to the UE, using resource elements that do not overlap with the ZP CSI-RS blocks.

In example 20, the subject matter of example 19, or any of the examples herein, wherein the first TTI consists of two OFDM symbols.

In example 21, the subject matter of example 19, or any of examples herein, wherein all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

In a 22^nd example, a UE may include circuitry to: receive an indication of a modulation and coding scheme that is to be used when wirelessly transmitting data using PDSCH resources; receive resource allocation information; calculate, based on the resource allocation information, an effective resource allocation size; determine a transport block size (TBS) for PDSCH data transmissions based on the indication of the modulation and encoding scheme and based on the effective resource allocation size; and receive data, for the UE, using the determined TBS, wherein receiving the data includes: decoding the data from resource elements associated with ZP CSI-RS blocks within the PDSCH.

In example 23, the subject matter of examples 22, or any of the examples herein, wherein the resource allocation information includes an actual number of available PDSCH resource elements.

In example 24, the subject matter of example 23, or any of the examples herein, wherein the circuitry is to calculate the effective resource allocation size as:

where ceil indicates the ceiling function, max indicates the maximum function, and NRE indicates the actual number of available PDSCH resource elements.

In example 25, the subject matter of example 22, or any of the examples herein, wherein the circuitry is to calculate the effective resource allocation size as:

max(ceil ("^⁵/") , 1),

where ceil indicates the ceiling function, max indicates the maximum function, TTI is a number of Orthogonal Frequency Division Multiplexing (OFDM) symbols used with the PDSCH, and NPRB represents the resource allocation information.

In example 26, the subject matter of example 22, or any of the examples herein, wherein the circuitry is to calculate the effective resource allocation size as:

max ceil (——— 1 , 1),

where ceil indicates the ceiling function, max indicates the maximum function, TTI is a number of OFDM symbols used with the PDSCH, and NPRB represents the resource allocation information.

In the preceding specification, various embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.

For example, while series of signals and/or operations have been described with regard to Figs. 4, 5, 7, and 8, the order of the signals may be modified in other implementations. Further, non-dependent signals may be performed in parallel.

It will be apparent that example aspects, as described above, may be implemented in many different forms of software, firmware, and hardware in the implementations illustrated in the figures. The actual software code or specialized control hardware used to implement these aspects should not be construed as limiting. Thus, the operation and behavior of the aspects were described without reference to the specific software code— it being understood that software and control hardware could be designed to implement the aspects based on the description herein.

Further, certain portions may be implemented as "logic" that performs one or more functions. This logic may include hardware, such as an application-specific integrated circuit ("ASIC") or a field programmable gate array ("FPGA"), or a combination of hardware and software.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to be limiting. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification.

No element, act, or instruction used in the present application should be construed as critical or essential unless explicitly described as such. An instance of the use of the term "and," as used herein, does not necessarily preclude the interpretation that the phrase "and/or" was intended in that instance. Similarly, an instance of the use of the term "or," as used herein, does not necessarily preclude the interpretation that the phrase "and/or" was intended in that instance. Also, as used herein, the article "a" is intended to include one or more items, and may be used interchangeably with the phrase "one or more." Where only one item is intended, the terms "one," "single," "only," or similar language is used.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for a baseband processor of User Equipment (UE) comprising circuitry to:

decode, based on information received via Radio Resource Control (RRC) signaling, configuration information for Zero Power Channel State Information Reference Signal (ZP CSI- RS) blocks in Physical Data Shared Channel (PDSCH) resources;

decode, based on information received via Downlink Control Information (DCI), an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks in the PDSCH resources; and

decode data, for the UE, from the indicated ZP CSI-RS blocks.

2. The apparatus of claim 1, wherein the circuitry includes:

one or more antennas, wherein the DCI is transmitted as part of the Physical Data Control Channel (PDCCH) using the one or more antennas.

3. The apparatus of claim 1, wherein the configuration information includes a plurality of potential ZP CSI-RS configurations, and wherein the circuitry is further to:

receive, via the DCI, an indication of one of the potential ZP CSI-RS configurations to use.

4. An apparatus of for a baseband processor of an evolved NodeB (eNB) comprising circuitry to:

generate, for transmission via Radio Resource Control (RRC) signaling to User

Equipment (UE), configuration information for Zero Power Channel State Information

Reference Signals (ZP CSI-RS) blocks in Physical Data Shared Channel (PDSCH) resources; generate, for transmission to the UE via Downlink Control Information (DCI), an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks; and causing transmission of data, to the UE, using the indicated ZP CSI-RS blocks in the

PDSCH.

5. The apparatus of claim 1 or 4, wherein the data transmissions in the ZP CSI-RS blocks are performed using a first transmission time interval (TTI), and wherein the UE is capable of communicating using a second TTI that is longer than the first TTI, data for the second TTI being communicated, to the UE, using resource elements that do not overlap with the ZP CSI-RS blocks.

6. The apparatus of claim 5, wherein the first TTI consists of two Orthogonal Frequency Division Multiplexing (OFDM) symbols.

7. The apparatus of claim 5,wherein all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

8. The apparatus of claim 5, wherein less than all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

9. A computer readable medium containing program instructions for causing one or more processors, associated with a User Equipment (UE), to:

decode, based on information received via Radio Resource Control (RRC) signaling, configuration information for Zero Power Channel State Information Reference Signal (ZP CSI- RS) blocks in Physical Data Shared Channel (PDSCH) resources; decode, based on information received via Downlink Control Information (DCI), an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks in the

PDSCH resources; and

decode data, for the UE, from the indicated ZP CSI-RS blocks.

10. The computer readable medium of claim 9, wherein the DCI is transmitted as part of the Physical Data Control Channel (PDCCH).

11. The computer readable medium of claim 9, where the configuration information includes a plurality of potential ZP CSI-RS configurations, and wherein the computer readable medium further includes program instructions for causing the one or more processors to:

receive, via the DCI, an indication of one of the potential ZP CSI-RS configurations to use.

12. The computer readable medium of claim 9, wherein the data transmissions in the ZP CSI-RS blocks are performed using a first transmission time interval (TTI), and wherein the UE is capable of communicating using a second TTI that is longer than the first TTI, data for the second TTI being communicated, to the UE, using resource elements that do not overlap with the ZP CSI-RS blocks.

13. The computer readable medium of claim of claim 12, wherein the first TTI consists of two Orthogonal Frequency Division Multiplexing (OFDM) symbols.

14. The computer readable medium of claim 12, wherein all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI- RS blocks.

15. The computer readable medium of claim of claim 12, wherein less than all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

16. User Equipment (UE) comprising:

means for receiving, via Radio Resource Control (RRC) signaling, configuration information for Zero Power Channel State Information Reference Signal (ZP CSI-RS) blocks in Physical Data Shared Channel (PDSCH) resources;

means for receiving, via Downlink Control Information (DCI), an indication of PDSCH data transmissions for the UE, at least some of the PDSCH data transmissions being performed using resources corresponding to the ZP CSI-RS blocks in the PDSCH resources; and

means for decoding data, for the UE, from the indicated ZP CSI-RS blocks.

17. The UE of claim 16, wherein the DCI is transmitted as part of the Physical Data Control Channel (PDCCH).

18. The UE of claim 16, wherein the configuration information includes a plurality of potential ZP CSI-RS configurations, the UE further comprising:

means for receiving, via the DCI, an indication of one of the potential ZP CSI-RS configurations to use.

19. The UE of claim 16, wherein the data transmissions in the ZP CSI-RS blocks are performed using a first transmission time interval (TTI), and wherein the UE is capable of communicating using a second TTI that is longer than the first TTI, data for the second TTI being communicated, to the UE, using resource elements that do not overlap with the ZP CSI- RS blocks.

20. The UE of claim 19, wherein the first TTI consists of two Orthogonal Frequency Division Multiplexing (OFDM) symbols.

21. The UE of claim 19, wherein all of the PDSCH data transmissions, using the first TTI, are performed using resources corresponding to the ZP CSI-RS blocks.

22. User Equipment (UE) comprising circuitry to:

receive an indication of a modulation and coding scheme that is to be used when wirelessly transmitting data using Physical Data Shared Channel Resources (PDSCH) resources; receive resource allocation information;

calculate, based on the resource allocation information, an effective resource allocation size;

determine a transport block size (TBS) for PDSCH data transmissions based on the indication of the modulation and encoding scheme and based on the effective resource allocation size; and

receive data, for the UE, using the determined TBS, wherein receiving the data includes: decoding the data from resource elements associated with Zero Power Channel State Information Reference Signals (ZP CSI-RS) blocks within the PDSCH.

23. The UE of claim 22, wherein the resource allocation information includes an actual number of available PDSCH resource elements.

24. The UE of claim 23, wherein the circuitry is to calculate the effective resource allocation size as:

where ceil indicates the ceiling function, max indicates the maximum function, and NRE indicates the actual number of available PDSCH resource elements.

25. The UE of claim 22, wherein the circuitry is to calculate the effective resource allocation size as:

max(ceil ("^⁵/") , 1),

where ceil indicates the ceiling function, max indicates the maximum function, TTI is a number of Orthogonal Frequency Division Multiplexing (OFDM) symbols used with the PDSCH, and NPRB represents the resource allocation information.