WO2018064551A1 - Preamble channel state information reference signal - Google Patents

Abstract

Embodiments of the present disclosure describe methods and apparatuses for generating and using a preamble channel state information reference signal.

Description

PREAMBLE CHANNEL STATE INFORMATION REFERENCE SIGNAL

Related Application

This application claims priority to U.S. Provisional Application Number 62/402,348, filed September 30, 2016, which is hereby incorporated by reference in its entirety.

Field

Embodiments of the present disclosure generally relate to the field of networks, and more particularly, to apparatuses, systems, and methods for generation and use of preamble channel state information reference signal.

Background

The following detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of various embodiments. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the various embodiments may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the various embodiments with unnecessary detail.

Incorrect channel state information ("CSI") due to variability induced by beamforming has a significant detrimental impact on system performance, especially on outage in millimeterwave ("ramWave") dense 5G networks. Current approaches for CSI reference signal ("RS") design and estimation in current networks rely on statically configured resources for channel and interference measurement. Interference averaging may then be relied upon to reflect an achievable modulation and coding scheme ("MCS"). 5G beamformed systems may have highly variable interference, which can detrimentally affect system performance.

Brief Description of the Drawings

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

Figure 1 illustrates an architecture of a system of a network in accordance with some embodiments. Figure 2 illustrates a hybrid beamforming architecture according to various embodiments. Figure 3 illustrates resource allocations of two subframes in accordance with some embodiments.

Figure 4 illustrates localized and distributed mapping according to some embodiments. Figure 5 illustrates a procedure according to some embodiments.

Figure 6 illustrates an example operation flow/algorithmic structure of an access node according to some embodiments.

Figure 7 illustrates an example operation flow/algorithmic structure of a user equipment according to some embodiments.

Figure 8 illustrates a forward/backward training according to some embodiments.

Figure 9 illustrates a device according to some embodiments.

Figure 10 illustrates hardware resources in accordance with some embodiments.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments that may be practiced. 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.

Various operations are described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter. However, the order of description does not imply that these operations are order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed or described operations may be omitted in additional embodiments.

For the purposes of the present disclosure, the phrases "A or B," "A and/or B," and "A/B" mean (A), (B), or (A and B).

The description may use the phrases "in an embodiment," or "in embodiments," which may each refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," and the like, as used with respect to embodiments of the present disclosure, are synonymous.

Various embodiments describe CSI estimation and feedback that may be used with improved beamformer design for interference-limited wireless networks. Some embodiments describe a preamble CSI RS ("PCSI-RS") that is structured in a way to accurately capture channel and interference characteristics that are expected to be experienced by a data packet transmission. Additional embodiments describe interference- aware transmit and receive beamforming based on forward/backward training. Such embodiments may improve user throughput and decrease outages experienced by cell- edge users.

Figure 1 illustrates an architecture of a system 100 of a network in accordance with some embodiments. The system 100 is shown to include a UE 104, which may be a smartphone (for example, a handheld touchscreen mobile computing device connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, Internet of things ("IoT") devices, smart sensors, laptop computers, desktop computers, wireless handsets, or any computing device including a wireless communications interface.

In embodiments in which the UE 104 comprises an IoT device, it may also include a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as machine-to-machine ("M2M") or machine-type communication ("MTC") for exchanging data with an MTC server or device via a public land mobile network ("PLMN"), Proximity-Based Service ("ProSe") or device-to-device ("D2D") communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (for example, keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network.

The UE 104 may be configured to connect, for example, communicatively couple, with an access node ("AN") 108 of a radio access network ("RAN") 110 via a Uu interface. The UE 104 may include a CSI generator 102 coupled with a transmit/receive circuitry 106. The access node 108 may include a scheduler 111 coupled with transmit/receive circuitry 112. Briefly, the scheduler 111 may determine which time/frequency resources may be used for uplink and downlink transmissions with the UE 104 on a subframe level and generate content that may be sent to the UE 104 to communicate those determinations. CSI generator 102 may use the transmit/receive circuitry 106 to determine CSI by measuring a downlink channel and send the feedback information to the transmit/receive circuitry 112. CSI as used herein may include a pre-coding matrix indicator ("PMI"), a channel quality indicator ("CQI"), or rank indication ("RI"). The transmit/receive circuitry 106 may also send a buffer status report ("BSR") to inform the access node 108 that the UE 104 has data to send in an uplink communication.

The scheduler 111 may receive the CQI and BSR, via the transmit receive circuitry 112, and compute a modulation and coding scheme ("MCS") and physical resource block ("PRB") mapping information, which may be sent to the UE 104 through a downlink transmission.

The RAN 110 may be, for example, an Evolved Universal Terrestrial Radio Access Network ("E-UTRAN") in which case the access node 108 may be an evolved node B ("eNB"), a NextGen RAN ("NG RAN") in which case the access node 108 may be a next generation node B ("gNB"), or some other type of RAN. The UE 104 may utilize an air- interface protocol to enable communicative coupling over the Uu interface. The air- interface protocol can be consistent with cellular communications protocols such as a Global System for Mobile Communications ("GSM") protocol, a code-division multiple access ("CDMA") network protocol, a push-to-talk ("PTT") protocol, a PTT over cellular ("POC") protocol, a Universal Mobile Telecommunications System ("UMTS") protocol, a 3GPP Long Term Evolution ("LTE") protocol, a fifth generation ("5G") protocol, a New Radio ("NR") protocol, and the like.

The access node 108 can terminate the air-interface protocol and can be the first point of contact for the UE 104. In some embodiments, the access node 108 can fulfill various logical functions for the RAN 110 including, but not limited to, radio network controller ("RNC") functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

To establish a connection with the access node 108, the UE 104 may perform a number of operations. The first operation may include, for example, synchronizing with a frequency to identify an operator with which the UE 104 is to connect. After synchronizing, the UE 104 may be able to read and process information blocks such as, for example, master information block ("MIB") and system information blocks ("SIBs"), to obtain information used to access a cell provided by the access node 108. The UE 104 may then perform a random access procedure to request the access node 108 to provide the UE 104 temporary resources for initial communication. Following the random access procedure, the UE 104 may establish an radio resource control ("RRC") connection by sending an RRC connection request message, which may also be referred to as an RRC Msg 3; receiving an RRC connection setup message; and sending an RRC connection setup complete message, which may be referred to as an RRC Msg 5. The UE 104 may be in an RRC- CON ECTED state after sending the RRC connection setup complete message.

In some embodiments, the RRC connection request message may include a UE identity, which may include a temporary mobile subscriber identity ("TMSI") or a random value, and a connection establishment cause. In some embodiments, the RRC connection setup message may include a default configuration for a first signaling radio bearer (SRBl) and other configuration information related to, for example, physical uplink shared channel ("PUSCH"), physical uplink control channel ("PUCCH"), physical downlink shared channel ("PDSCH"), PCSI-RS, CSI report, sounding reference signal, antenna

configuration, scheduling request, etc. In some embodiments, the RRC connection setup complete message may include information about a selected PLMN and UE-specified non- access stratum ("NAS") layer information.

In accordance with some embodiments, the UE 104 can be configured to communicate using Orthogonal Frequency-Division Multiplexing ("OFDM") communication signals with other UEs or with the access node 108 over a multicarrier communication channel in accordance with various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access ("OFDMA") communication technique (for example, for downlink communications) or a Single Carrier Frequency Division Multiple Access ("SC-FDMA") communication technique (for example, for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers. In some embodiments, a downlink resource grid can be used for downlink transmissions from the access node 108 to the UE 104, while uplink transmissions can utilize similar techniques. The grid can be a time-frequency grid, called a resource grid or time- frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of PRBs, which describe the mapping of certain physical channels to resource elements. Each PRB (or simply "resource block") comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical channels that are conveyed using such resource blocks. These include the PUSCH and the PDSCH.

The PDSCH may carry user data and higher-layer signaling to the UE 104. The PUSCH may be used to carry RRC signaling messages, uplink control information, and application data to the AN 108.

The UE 104 and AN 108 may communicate control signals over one or more control channels including, for example, a physical downlink control channel ("PDCCH") and the PUCCH.

The PDCCH may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UE 104 about the transport format, resource allocation, and HARQ information related to the uplink shared channel. Downlink scheduling (assigning control and shared channel resource blocks to the UE 104 within a cell) may be performed at the access node 108 based on CSI fed back from the UE 104. The downlink resource assignment information may be sent on the PDCCH used for (for example, assigned to) the UE 104.

The RAN 110 may be communicatively coupled to a core network ("CN") 116 through an SI interface. The CN 116 may provide various connectivity and management operations to provide for the routing of network traffic between the RAN 110 and external networks. Figure 2 illustrates a hybrid beamforming architecture 200 in accordance with some embodiments. The hybrid beamforming architecture 200 (hereinafter "architecture 200") may include both analog and digital beamforming components. The architecture 200 may be deployed in Tx/Rx circuitry of either the UE 104 or the access node 108.

The architecture 200 may include baseband precoder 204 and baseband precoder 206 to receive signals from higher-layer components and to generate precoded symbols that are distributed across No spatial streams. In particular, baseband precoding 204 may receive synchronization and common control signals, while baseband precoder 206 may receive user-specific control and data.

The baseband precoders 204 and 206 may provide the precoded symbols to ND digital ports, which may gate the precoded symbols to an OFDM multiplexer ("MUX") 208. The OFDM MUX 208 may output the streams to No digital-to-analog converters (DACs) 212. Upon converting the streams to the analog domain, the DACs 212 may provide the analog streams to a corresponding number of radio frequency ("RF") chains 216 and

beamformers ("BFs") 220. The beamformers 220 may each receive control signals from beam controller 224 and output beamformed streams NA having desired phase and amplitude characteristics. The beamformed streams NA may be provided to a combiner 228 that combines the streams and provides the combined streams to an antenna array 232. The antenna array 232 may be a linear antenna array having equally spaced antenna elements.

In situations in which the architecture 200 is employed in the access node 108, the architecture 200 may include a fully active array that is capable of, for example, 16-32 RF chains for a sub-6 GHz system, and 128 to 256 antenna elements. For a sub-6 GHz system, the UE 104 may include a plurality of antenna elements, for example, 2, 4, or 8. For a mmWave system, the UE 104 may employ analog beamforming with 2-4 RF chains and 16-32 antenna elements in a subarray structure.

In sub-6 GHz systems, a typical deployment scenario may be a dense deployment of small cells, serving a high user density in urban areas. Ensuring high bit rate services with quality of service ("QoS") guarantees for each user/application with the high density of users may be achieved by utilizing the spatial domain for multi-user multiplexing, along with advanced interference suppression/cancellation or mitigation. The architecture 200 may be used to support such high-order multi-user, multiple input multiple output ("MU- MIMO") systems. However, a challenge in achieving QoS guarantees and sustainable high bit rates comes from the variability in interference. This impacts the reliability of CSI available at the transmitters. Intra-cell interference arises out of other MU-MIMO co- scheduled users. Inter-cell interference comes from beamformed MU-MIMO

transmissions in other cells. Thus, embodiments describe a system design in sub-6GHz that address methods for the system to predict and mitigate both intra-cell and inter-cell interference. A majority of deployments in sub-6GHz may be time-division-duplex (TDD) and, therefore, reciprocity-based beamforming for digital precoding/beamformer design may be utilized.

Poor propagation conditions in mmWave systems may be the result of links being power limited, due to which high gain beamforming both at the transmitter and receiver may be desired to close the link. Typical deployments, especially with indoor UEs, would necessarily have to consider small inter-site distances ("ISDs") in the range of 50-100 meters to ensure reasonable pathloss to cell-edge UEs. Intercell interference may beome a domination factor for many UEs (on the downlink ("DL")) at these transmitter densities. Due to the highly spatially-selective beams, inter-cell interference may be highly variable (the so-called "torch-light" effect) and may depend on the changing set of users scheduled in neighboring cells. Due to the factors outlined above, it can be seen that both sub-6 GHz and mmWave systems may have to contend with highly variable CSI that may be difficult to predict. Typical CSI feedback design in LTE advanced ("LTE-A") relies on a channel quality indicator ("CQI") computation that assumes interference stability (such as in non- beamformed systems), or interference averaging/randomization. Outer-loop link adaptation ("OLLA") mechanisms, either at the UE or at the eNB scheduler, can attempt to make the link robust to ensure a certain QoS in the face of highly varying CSI feedback. However, system performance will be far from optimal since the OLLA loop will result in allocating conservative MCSs to ensure a certain average target frame error rate ("FER") is met.

Interference in beamformed systems is inherently unpredictable due to the fact that user scheduling can change from one subframe to another. Since each user is beamformed, this results in interference fluctuating significantly from the time of CSI measurement to the time of scheduling. The following embodiments describe accurate CSI computation and feedback to enable the eNB 108 to provide desired system performance in terms of outage and capacity metrics.

In enhanced mobile broadband (eMBB) applications, which is a target application of 5G systems, user data may arrive as a large collection of packets, which typically takes many multiple subframes to flush. In this scenario, the scheduler 111 of the eNB 108 can do look-ahead scheduling to allocate time/frequency resources to the UE 104 at least a few subframes ahead of time. In some embodiments, the eNB 108 may configure CSI generator 102 of the UE 104 to measure and report CSI corresponding to the exact schedule of beams that is to be expected in the following packet data transmission.

Following this, the scheduler 111 can accurately determine the MCS achievable for the corresponding data transmission.

In some embodiments, a PCSI-RS may be sent by all transmitters of the eNB 108 (or cell) synchronously. A PCSI-RS in subframe n may have the same (analog and digital) beams and multi-user resource block allocation as the following PDSCH in subframe n+k (for example, k=\, 2). The downlink ("DL") CSI based on the PCSI-RS may, therefore, be used to determine a truly achievable MCS for each user in the network for subframe n+k. The measurement of PCSI-RS may result in a computation of the actual signal to interference and noise ratio ("SINR") reflecting both intra-cell (MU-MIMO) and inter-cell interference. Further, it subsumes scenarios of multi-site (for example, coordinated multipoint ("CoMP") plus MU-MIMO) transmissions, since the UE 104 only measures its SINR over a known set of PRBs that the PDSCH would be transmitted on using transmit beams from one or multiple transmission points. Following reception of the PCSI-RS by the transmit/receive circuitry 106, the CSI generator 102 of the UE 102 may compute a CSI. The transmit/receive circuitry 106 may feed the computed CSI back to the access node 108 in the same subframe as the PCSI-RS transmission. In some embodiments, the computed CSI may be fed back in the last symbol of the subframe. The CSI feedback may occur on an uplink symbol, which may be in PUCCH. This allows the scheduler 111 time to allocate MCS and send the control and data transmission for the UE 104 in subframe n+k.

Figure 3 illustrates a resource allocation 300 of subframe n 304 and subframe n+k 308 utilizing PCSI-RS in accordance with some embodiments. User allocations may be performed in a granularity of No PRBs, which may be referred to as a PRB group. The granularity size may be chosen by taking into account eMBB applications, for example. Options may include NG={ 12, 25, 50} PRBs in one PRB group, which would result in a total of {8, 4, 2} PRB groups in a 100 MHz component carrier (CC). A PRB group for data transmission may map to a unique set of resources of PCSI-RS. These resources can be identical to the PRB group as shown in Figure 3 or could be a set of distributed resource elements ("REs"). Figure 4 illustrates a localized mapping scheme 404, which generally relates to Figure 2, and a distributed mapping scheme 408 in accordance with some embodiments. The localized mapping 404 may be desirable in some situations as it has an advantage of not only accurately capturing the interference pattern but also the desired channel that will be experienced by the PDSCH packet.

For each PRB group, the PCSI-RS (referred to as "PRS" in Figure 3) may be provided as a configured sequence spanning a PRB group worth of REs, occupying the middle symbol in a subframe. The scheduler 111 may pre-determine a number of PRBs (and possibly a coarse MCS) in subframe n for transmission of PDSCH in subframe n+k in order to enable a PCSI-RS transmission in subframe n for the set of scheduled UEs in subframe n+k. For example, the scheduler 111 may determine that in subframe n, UE2 data is to be transmitted in first PRB group 312 and second PRB group 316. This may be

communicated to UE2 using the PDCCH of the first PRB group 312 and the second PRB group 316, respectively, in subframe n 304. The scheduler 111 may also determine that in subframe n, UE1 data is to be transmitted in third PRB group 320 and fourth PRB group 324. This may be communicated to UE1 using the PDCCH of the third PRB group 320 and fourth PRB group 324, respectively. The scheduler 111 may also know that, in subframe n+k 308, UE2 data is to be transmitted in the first PRB group 312 while UE1 data is to be transmitted in the other three PRB groups. Therefore, the scheduler 111 may schedule transmission of PCSI-RS in subframe n 304 that matches the distribution of the data transmissions of subframe n+k 308. That is, PCSI-RS for UE2 may be transmitted in the first PRB group 312, while

PCSI-RS for UE1 may be transmitted in the second PRB group 316, the third PRB group 320, and the fourth PRB group 324.

UE2 may receive and measure the PCSI-RS transmitted in the first PRB group 312 in subframe « 304 and generate corresponding CSI. UE2 may then transmit C SI in an uplink transmission in a CSI feedback ("CSI-FB") allocation in the last symbol of PRB group 312 in subframe n 304.

UE1 may receive and measure the PCSI-RS transmitted in PRB groups 316, 320, and 324 in subframe n 304 and generate corresponding CSI. UE1 may then transmit CSI in uplink transmissions in CSI-FB allocations in the last symbol of PRB groups 316, 320, and 324 in subframe n 304.

In some embodiments, the PCSI-RS sequence may be derived from UE-specific virtual cell identifier ("VCID") (similar to demodulation reference signal ("DMRS")). In this case, all UEs configured with the same VCID may potentially listen to the same PCSI-RS. In some embodiments, the PCSI-RS sequence may be derived from a UE-specific sequence. A UE can do a sequence correlation over every PRB group to determine if its PCSI-RS is transmitted or not in that group. In this manner, for example, UE1 may determine that the PCSI-RS of the second PRB group 316 in subframe n 304 is to be used as a basis for CSI measurement and reporting by UE1.

In some embodiments, when UE-specific sequence is used to derive a PCSI-RS (and possibly when UE-specific VCID is used), a common search space PDCCH can be transmitted in subframe n 304 to indicate PRB boundaries for allocation in subframe n+k 308. This may reduce the number of search options for PCSI-RS. The number of search options may be indicated as a

bitmap message, which NmaxRB is the maximum number of resource blocks.

Different embodiments may employ different PCSI-RS and PDSCH allocation mechanisms. For example, some embodiments may include a fully dynamic allocation of PCSI-RS/PDSCH. In these embodiments, the PCSI-RS sequence may be based on a UE- specific allocation and may require blind detection at the UE. Code-multiplexed PCSI-RS may be sent based on a number of layers supported by the UE. The PUCCH allocation for transmitting the CSI feedback on the uplink may be per PRB group. If a UE detects its PCSI-RS sequence on a set of PRB groups, it will transmit the CSI on the corresponding PRB groups allocated to PUCCH on the uplink. For example, by detecting its PCSI-RS sequence in the second PRB group 316 of subframe n 304, UE1 may know to transmit corresponding CSI feedback on the last symbol of the second PRB group 316 of subframe n 304. The mapping between PCSI-RS regions and corresponding PUCCH regions may be a logical or physical mapping.

In some embodiments, the PCSI-RS and PDSCH allocation may be based on a quasi-semi persistent allocation mechanism. In these embodiments, the access node 108 may indicate semi-persistent PRB group and subframe allocation to users via semi-persistent scheduling ("SPS") PDCCH grants. This may not require any blind detection at the UEs. The MCS and MIMO configuration may be signaled dynamically per subframe upon reception of the CSI feedback. This information may be signaled by using a reduced-payload UE-specific PDCCH or by a common PDCCH message intended for all UEs that are scheduled in subframe n+k 308.

Quasi-semi-persistent allocation may also provide for pre-allocation of the CSI-FB on PUCCH corresponding to the semi-static PRB allocation on the downlink.

It may be noted that in some embodiments, not every data transmission will need to be accompanied by a previous PCSI-RS. Rather, the CSI fed back for a particular PCSI-RS may be used for more than one data transmission. This may lead to savings in control signaling overhead.

Upon receiving the PCSI-RS, the CSI generator 102 of UE 104 may compute an achievable signal to interference and noise ratio ("SINR") per PRB group and final effective SINR/CQI over allocated PRB groups. In some embodiments, the UE 104 may be configured to combine different PRB groups and send multiple reports. For example, the UE may be instructed to not combine over all allocated PRB groups, but rather send one CQI per subset of PRB groups. In this case, the UE may compute two CQIs, for example, for two subbands within the allocation and send a CQI report for each using those corresponding subbands.

An interference covariance estimation on a given PRB group may be performed by subtracting the channel estimates from the received PCSI-RS signal. In this manner, no separate interference measurement resources may need to be used.

In some embodiments, DMRS processes may be bootstrapped to PCSI-RS. For example, PCSI-RS-based channel and interference covariance estimates, transmitted in subframe n, may also be used for data demodulation in subframe n+k. Any relevant allocation region of PCSI-RS in subframe n for a particular UE can be used to boot-strap DMRS in subframe n for that UE. For example, if the PCSI-RS is transmitted in subframe n using PRB group 1, but it also has data scheduled on PRB group 1 in subframe n, then the UE can use the channel estimates from the PCSI-RS in subframe n (over PRB group 1) to potentially help in the channel estimation and demodulation of its PDSCH in subframe n (over PRB group 1), since the frequency regions overlap.

Figure 500 illustrates a PCSI-RS procedure 500 in accordance with some embodiments. At 504, the procedure 500 may include the access node 108 transmitting, and the UE 104 receiving, a PCSI-RS in subframe n.

Upon receiving the PCSI-RS, the UE 104 may perform CSI measurements including, for example, SINR/CQI measurements and generate CSI-FB at 508.

The procedure 500 may further include, at 512, the UE 104 transmitting and the access node 108 receiving the CSI feedback in subframe n. The CSI-FB may be transmitted in the PUCCH.

The procedure 500 may further include, at 516, the access node 108 determining an MCS that is to be used for a PDSCH transmission to the UE 104. The MCS determination may be based on the CSI feedback and provide accurate information about the state of the particular resources that are anticipated to be used by the PDSCH transmission in a following subframe.

The procedure 500 may further include, at 520, the access node 108 transmitting and the UE 104 receiving a PDCCH transmission in subframe n+k. The PDCCH transmission may include information about the schedule of the PDSCH of the same subframe including, for example, the MCS that will be used to transmit the PDSCH.

The procedure 500 may further include, at 524, the access node 108 transmitting and the UE 104 receiving the PDSCH transmission in subframe n+k.

Figure 6 illustrates an example operation flow/algorithmic structure 600 of a transmission process of the access node 108 according to some embodiments.

The flow/structure 600 may include, at 604, prescheduling a PDSCH transmission. The prescheduling of the PDSCH transmission may be facilitated by the access node 108 having a large block of data to be transmitted to the UE 104 over multiple subframes. The prescheduling may be performed by the access node 108 during subframe n and relate to the PDSCH transmission anticipated to be transmitted in subframe n+k. To preschedule the PDSCH transmission, the access node 108 may determine an anticipated resource allocation in subframe n+k for the PDSCH transmission. For example, the scheduler 111 may determine that a particular set of PRBs are likely to be used to transmit PDSCH transmission. In some embodiments, the scheduler 111 may also determine an initial MCS that may possibly be used to transmit the PDSCH as part of the prescheduling.

The flow/structure 600 may further include, at 608, scheduling a PCSI-RS in subframe n. The PCSI-RS may be scheduled on the same resources that are prescheduled for the PDSCH transmission. The scheduling of the PCSI-RS may include transmitting resource allocation information of the PCSI-RS in DCI for the UE. The resource allocation information may identify the resources that are to be used to transmit the PCSI-RS. In some embodiments, the resource allocation information may also identify resources that are to be used to transmit the CSI feedback that corresponds to the PCSI-RS.

The flow/structure 600 may further include, at 612, receiving CSI. The CSI, which may be received in a PUCCH transmission that occurs in the same subframe in which the PCSI- RS was sent, may be an indication of the state of the channel on the resources that are intended to be used for a subsequent PDSCH transmission. In some embodiments, the CSI may be transmitted in the last symbol of the subframe.

The flow/structure 600 may further include, at 616, scheduling a PDSCH transmission. The PDSCH transmission for the UE 104 may be scheduled for one or more subframes after the subframe in which the PCSI-RS and CSI is sent.

The scheduling of the PDSCH transmission may include determining, based on the CSI, the desired transmission parameters (for example, MCS, rank, precoding, or one or more subbands) that are to be used for the PDSCH tranmission. The scheduling may also include providing resource information, in the PDCCH, to identify the resources that are to be used to transmit the scheduled PDSCH transmission and the transmission parameters determined from the fed back CSI.

The PDSCH may be transmitted after the indication of the scheduling is transmitted in the PDCCH.

Figure 7 illustrates an example operation flow/algorithmic structure 700 of a transmission process of the UE 104 according to some embodiments.

The flow/structure 700 may include, at 704, processing a PCSI-RS. The PCSI-RS may be transmitted by a transmit/receive point ("TRP") on a first set of resources in a first subframe. The TRP may be part of or otherwise controlled by the access node 108. The processing of the PCSI-RS may include the UE 104 determining a resource allocation information of the PCSI-RS in DCI and demodulating and decoding the PCSI-RS based on the resource allocation information. In some embodiments, the processing of the PCSI-RS may be performed by the UE 104 identifying a predetermined resource allocation list (including, for example, a set of PRB groups) and blindly decoding transmissions on resources of the predetermined resource allocation list until successfully decoding the PCSI-RS. The decoding of the PCSI-RS sequence may be based on a VCID configured at the UE 104 or on a UE-specific sequence.

The flow/structure 700 may further include, at 708, measuring CSI from the PCSI-RS received and processed at 704. The measuring of the CSI may include the CSI generator 102 estimating a desired channel from the PCSI-RS after demodulation and decoding performed by the transmit/receive circuitry 106. The CSI generator 102 may further estimate interference based on the estimation of the desired channel. The CSI generator 102 may then determine transmission parameters for subsequent PDSCH transmission. The transmission parameters may include, but are not limited to, CQI, rank, precoding, or one or more subbands to be used for the PDSCH transmission.

The flow/structure 700 may further include, at 712, reporting the CSI. The CSI feedback may include the transmission parameters determined at 708. In some embodiments, the CSI may be reported in the PUCCH of the same subframe in which the PCSI-RS was transmitted.

The flow/structure 700 may further include, at 716, processing a PDSCH transmission. The processing of the PDSCH transmission may include determining the scheduling of the PDSCH transmission by referencing PDCCH of a subframe in which the PDSCH transmission is transmitted. The PDCCH may include DCI that the UE 104 uses to identify the resource allocation information/transmission parameters. The transmit/receive circuitry 106 may then demodulate and decode the scheduled PDSCH transmission

The above concepts relating to PCSI-RS may be used to increase accuracy of beamformer training that in dense networks. Joint estimation of network-wide optimal transmit and receive beams in dense networks provides a variety of challenges. These challenges arise because a receive beam for a user may need to be tuned based on desired and interfering transmit beams from its serving and interfering cells. On the other hand, the transmit beams may need to be optimized taking into account the effective channel to the desired and interfering users, which in turn depends on the receive beams that those UEs will use. Since an interference-limited wireless network has these interactions extending throughout the network, it is not feasible to design a centralized solution to the problem.

To address these challenges, forward/backward (F/B) training has been proposed as an iterative method that achieves jointly close-to-optimal transmit/receive beams in an interference network, using multiple over-the-air beam updates. An alternate approach would be to feed back channel estimates from a subset of UEs to compute Tx/Rx beams using alternating optimization, but this entails significant information exchange requirements between access nodes.

F/B training may assume the UE 104 is a customer-provided equipment ("CPE") type UE that has multiple (>=4) receive antennas and can be phase calibrated between transmit and receive. F/B training may also be based on the assumption that the TDD network is tightly synchronized. The basic procedure of F/B training includes a transmitter ("node 1") transmitting a first training signal with an initial transmit ("Tx") beam to a receiver ("node 2"). Node 2 may compute a minimum mean squared error ("MMSE") receive ("Rx") beam based on the training signal. Node 2 may then transmit a second training signal with a Tx beam equal to the previous Rx beam. Node 1 may receive the second training signal using an MMSE Rx beam. Node 1 may then transmit a third training signal with the Tx beam being equal to the previous Rx beam. One or more additional iterations may be performed.

Figure 8 illustrates F/B network beamformer training 800 according to some

embodiments. The training 800 utilizes the PCSI-RS and CSI-FB mechanisms described herein.

At 804, the access node 108 may transmit the PCSI-RS with an initial set of beams, wi, for scheduled users (including the UE 104). The initial transmit beam may be set to the latest beam for a particular user obtained from previous beam training instances or may be set in other manners.

The beams may travel through a channel, H. The UEs (including the UE 104) may compute a desired Rx filter, vi. The desired Rx filter may be computed using an MMSE filter that estimates CSI achievable with a particular Rx beam. The filter that is associated with the highest achievable CSI may be considered the desired Rx filter.

The UE 104 may calculate a CSI (as described herein) and determine a channel for transmitting the CSI feedback. The CSI-FB channel (for example, the PUCCH) may be allocated as a 1-1 mapping to the PRB allocation as the DL data channel used to transmit the PCSI-RS on the downlink. At 808, the UE 104 may transmit the CSI-FB (with DMRS) using a transmit filter, vi, set to be equal to the receive filter that was used by the UE 104 for receiving the PCSI-RS. The CSI-FB uplink may travel through a channel, H^T, which may be a transpose of the downlink channel.

A receiver of the access node 108 may compute a desired Rx filter, W2, using an MMSE filter as discussed above, for receiving the CSI-FB channel.

The access node 108 may compute an MCS achievable using the CSI information as detailed herein.

At 812, the access node 108 may transmit PDSCH using the allocated MCS and a Tx filter, W2, equal to the desired Rx filter computed at 808 for receiving the CSI-FB channel. The PDSCH DL may be transmitted through channel H.

As a result, the training 800 achieves two iterations of the F/B algorithm, which may be sufficient to obtain most of the performance benefit. However, other embodiments may use other number of iterations.

Embodiments described herein may be implemented into a system using any suitably configured hardware or software. Figure 9 illustrates, for one embodiment, example components of an electronic device 900. In embodiments, the electronic device 900 may be, implement, be incorporated into, or otherwise be a part of UE 104, AN 108, or some other device.

In some embodiments, the electronic device 900 may include application circuitry 902, baseband circuitry 904, RF circuitry 906, front-end module (FEM) circuitry 908 and one or more antennas 910, coupled together at least as shown. In embodiments where the electronic device 900 is implemented in or by an AN 108, the electronic device 900 may also include network interface circuitry (not shown) for communicating over a wired interface (for example, an X2 interface, an S I interface, and the like).

As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, 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. The 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 902a. The processor(s) 902a may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors 902a may be coupled with or may include computer-readable media 902b (also referred to as "CRM 902b," "memory 902b," "storage 902b," or "memory /storage 902b") and may be configured to execute instructions stored in the CRM 902b to enable various applications or operating systems to run on the system.

The 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 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 circuity 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, 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, and the like. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 904 may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 904 may include convolution, tail-biting convolution, turbo, Viterbi, 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 (E-UTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), 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 or RRC layers. In some embodiments, the CPU 904e may provide frequency hopping configuration by identifying frequency hopping information and determining a frequency hopping pattern that may be used by the encoding/decoding circuitry.

In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 904f. The audio DSP(s) 904f may include elements for

compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. The baseband circuitry 904 may further include computer-readable media 904g (also referred to as "CRM 904g", "memory 904g", "storage 904g", or "CRM 904g"). The CRM 904g may be used to load and store data or instructions for operations performed by the processors of the baseband circuitry 904.

CRM 904g for one embodiment may include any combination of suitable volatile memory or non-volatile memory. The CRM 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 CRM 904g may be shared among the various processors or dedicated to particular processors. Components of the baseband circuitry 904 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 E-UTRAN 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 that 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 that 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, 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 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 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 of the transmit signal path may be arranged for direct downconversion 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 integrated 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+l 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+l 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 application circuitry 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 application circuitry 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+l (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 that may include circuitry configured to operate on RF signals received from one or more antennas 910, 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 that 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 910. 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 908 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 910).

In some embodiments, the electronic device 900 may include additional elements such as, for example, a display, a camera, one or more sensors, or interface circuitry (for example, input/output (I/O) interfaces or buses) (not shown). In embodiments where the electronic device is implemented in or by an AN, the electronic device 900 may include network interface circuitry. The network interface circuitry may be one or more computer hardware components that connect electronic device 900 to one or more network elements, such as one or more servers within a core network or one or more other eNBs via a wired connection. To this end, the network interface circuitry may include one or more dedicated processors or field programmable gate arrays (FPGAs) to communicate using one or more network communications protocols such as X2 application protocol (AP), SI AP, Stream Control Transmission Protocol (SCTP), Ethernet, Point-to-Point (PPP), Fiber Distributed Data Interface (FDDI), or any other suitable network communications protocols.

In some embodiments, the electronic device 900 may be configured to perform one or more processes, techniques, or methods as described herein, or portions thereof. For example, the electronic device 900 may implement the generation and use of PCSI-RS as described herein including, for example, the flows/structures of Figures 6 or 7 or the training 800 of Figure 8.

Figure 10 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (for example, a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, Figure 10 shows a diagrammatic representation of hardware resources 1000 including one or more processors (or processor cores) 1010, one or more memory /storage devices 1020, and one or more communication resources 1030, each of which may be communicatively coupled via a bus 1040. For embodiments where node virtualization (for example, network function virtualization ("NFV")) is utilized, a hypervisor 1002 may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources 1000.

The processors 1010 (for example, a CPU, a reduced instruction set computing ("RISC") processor, a complex instruction set computing ("CISC") processor, a graphics processing unit ("GPU"), a digital signal processor ("DSP") such as a baseband processor, an application specific integrated circuit ("ASIC"), a radio-frequency integrated circuit ("RFIC"), another processor, or any suitable combination thereof) may include, for example, a processor 1012 and a processor 1014. The processors may correspond to any processors of baseband circuitry 904 of Figure 9.

The memory /storage devices 1020 may include main memory, disk storage, or any suitable combination thereof. The memory /storage devices 1020 may include, but are not limited to, any type of volatile or non-volatile memory such as dynamic random access memory ("DRAM"), static random-access memory ("SRAM"), erasable programmable read-only memory ("EPROM"), electrically erasable programmable read-only memory ("EEPROM"), Flash memory, solid-state storage, etc. The memory /storage devices 1020 may correspond to any processors of baseband circuitry 904 of Figure 9.

The communication resources 1030 may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices 1004 or one or more databases 1006 via a network 1008. For example, the communication resources 1030 may include wired communication components (for example, for coupling via a Universal Serial Bus ("USB")), cellular communication components, near-field communication ("NFC") components, Bluetooth® components (for example, Bluetooth® Low Energy), Wi-Fi® components, and other communication components.

Instructions 1050 may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors 1010 to perform any one or more of the methodologies regarding the PCSI-RS discussed herein.

The instructions 1050 may cause the processors 1010 to perform the operation flow/algorithmic structure 600, 700, training 800, or other operations of a UE or AN described herein.

The instructions 1050 may reside, completely or partially, within at least one of the processors 1010 (for example, within the processor's cache memory), the memory /storage devices 1020, or any suitable combination thereof. Furthermore, any portion of the instructions 1050 may be transferred to the hardware resources 1000 from any combination of the peripheral devices 1004 or the databases 1006. Accordingly, the memory of processors 1010, the memory /storage devices 1020, the peripheral devices 1004, and the databases 1006 are examples of computer-readable and machine-readable media.

The resources described in Figure 10 may also be referred to as circuitry. For example, communication resources 1030 may also be referred to as communication circuitry 1030. Some non-limiting examples are provided below.

Example 1 includes an apparatus having circuitry to: preschedule a physical data shared channel ("PDSCH") data transmission for a user equipment ("UE"); schedule a preamble channel state information-reference signal ("PCSI-RS") for the UE; receive channel state information ("CSI") associated with the PCSI-RS from the UE; and schedule the PDSCH transmission for the UE based on the CSI. Example 2 includes the apparatus of example 1, wherein to preschedule the PDSCH transmission the apparatus is to determine a resource allocation for the PDSCH transmission for the UE.

Example 3 includes the apparatus of example 1 or 2, wherein to schedule the PCSI-RS the apparatus is to transmit resource allocation information of the PCSI-RS in downlink control information ("DO") for the UE, wherein the circuitry is to transmit the PCSI-RS according to the resource allocation information of the PCSI-RS.

Example 4 includes the apparatus of example 3, wherein the resource allocation information further identifies resources that are to be used to transmit CSI feedback that corresponds to the PC SI-RS .

Example 5 includes the apparatus of example 1 or 2, wherein to schedule the PCSI-RS the apparatus is to transmit the PCSI-RS according to pre-determined resource allocation list for the UE, wherein the pre-determined resource allocation list includes a plurality of resource allocation options for the UE.

Example 6 includes the apparatus of example 1 or 2, wherein to schedule the PDSCH transmission the apparatus is to determine a modulation and coding scheme ("MCS"), a rank, a precoding, or one or more sub-bands for the PDSCH transmission to the UE based on the CSI.

Example 7 includes the apparatus of example 6, wherein the circuitry is further to:

transmit the PDSCH transmission to the UE based on the determined MCS, rank, precoding, or one or more sub-bands.

Example 8 includes an apparatus having circuitry to: process a preamble channel state information-reference signal ("PCSI-RS") received on a first set of resources in a first subframe; measure CSI from the PCSI-RS; report the CSI in the first subframe; and process a physical downlink shared channel ("PDSCH") data transmission received on the first set of resources in a second subframe.

Example 9 includes the apparatus of example 8, wherein to process the PCSI-RS the apparatus is to: determine resource allocation information of the PCSI-RS in downlink control information ("DO"); and demodulate and decode the PCSI-RS based on the resource allocation information.

Example 10 includes the apparatus of example 8 or 9, wherein to process the PCSI-RS the apparatus is to: identify a pre-determined resource allocation list; and blindly decode transmissions on resources of the pre-determined resource allocation list until successful decoding the PCSI-RS. Example 11 includes the apparatus of example 8 or 9, wherein to measure the CSI from the PCSI-RS the apparatus is to: estimate a desired channel from PCSI-RS after demodulation and decoding; and estimate interference based on the estimation of the desired channel.

Example 12 includes the apparatus of example 11, wherein to measure the CSI from the PCSI-RS the apparatus is to: determine a channel quality indicator ("CQI"), rank, precoding, or one or more subbands based on the estimation of the desired channel and the estimation of the interference.

Example 13 includes the apparatus of example 8 or 9, wherein the CSI includes a channel quality indicator ("CQI"), rank, precoding matrix indicator ("PMI"), or one or more sub- bands.

Example 14 includes the apparatus of example 8 or 9, wherein the instructions, when executed, further cause the apparatus to: identify resource allocation information of the PDSCH based on downlink control information ("DCI"); identify MCS of the PDSCH based on the DCI; and process the PDSCH based on the resource allocation information and the MCS.

Example 15 includes an apparatus having circuitry to: transmit a preamble channel state information-reference signal ("PCSI-RS") in a first subframe; receive channel state information ("CSI") feedback associated with the PCSI-RS in the first subframe; and transmit a physical downlink shared channel ("PDSCH") transmission in a second subframe based on the CSI feedback.

Example 16 includes the apparatus of example 15, wherein to receive the CSI feedback, the apparatus is to determine a desired receive filter, using a minimum mean square error filter, to receive the CSI feedback.

Example 17 includes the apparatus of example 16, wherein to transmit the PDSCH transmission, the apparatus is to set a transmit filter equal to the desired receive filter and to transmit the PDSCH transmission using the transmit filter.

Example 18 includes an apparatus having circuitry to: receive a preamble channel state information-reference signal ("PCSI-RS") in a first subframe; measure channel state information ("CSI") based on the PCSI-RS; and transmit the CSI in the first subframe. Example 19 includes the apparatus of example 18, wherein to receive the PCSI-RS, the apparatus is further to: determine a desired receive filter, using a minimum mean square error filter, to receive the PCSI-RS. Example 20 includes the apparatus of example 19, wherein to transmit the CSI in the first subframe, the apparatus is further to set a transmit filter equal to the desired receive filter and to transmit the CSI using the transmit filter.

Example 21 includes an apparatus comprising: means to preschedule a physical data shared channel ("PDSCH") data transmission for a user equipment ("UE"); means to schedule a preamble channel state information-reference signal ("PCSI-RS") for the UE; means to receive channel state information ("CSI") associated with the PCSI-RS from the UE; and means to schedule the PDSCH transmission for the UE based on the CSI.

Example 22 includes the apparatus of example 21, wherein means to preschedule the PDSCH transmission is to determine a resource allocation for the PDSCH transmission for the UE.

Example 23 includes the apparatus of example 21 or 22, wherein means to schedule the PCSI-RS the apparatus is to transmit resource allocation information of the PCSI-RS in downlink control information ("DCI") for the UE, and apparatus further comprises: means to transmit the PCSI-RS according to the resource allocation information of the PCSI-RS. Example 24 includes the apparatus of example 23, wherein the resource allocation information further identifies resources that are to be used to transmit CSI feedback that corresponds to the PCSI-RS.

Example 25 include the apparatus of example 21 or 22, wherein means to schedule the PCSI-RS is to transmit the PCSI-RS according to pre-determined resource allocation list for the UE, wherein the pre-determined resource allocation list includes a plurality of resource allocation options for the UE.

Example 26 includes an apparatus comprising: scheduler circuitry to schedule a first subframe to include preamble channel state information-reference signal ("PCSI-RS"); transmit/receive circuitry to transmit the PCSI-RS in a first subframe based on the schedule of the first subframe; and receive channel state information ("CSI") feedback associated with the PCSI-RS in the first subframe; wherein the scheduler circuitry is to schedule a second subframe to include a physical downlink shared channel ("PDSCH") transmission based on the CSI feedback, and the transmit/receive circuitry is to transmit the PDSCH transmission in the second subframe based on the schedule of the second subframe.

Example 27 includes the apparatus of example 26, wherein the transmit/receive circuitry is to determine a desired receive filter, using a minimum mean square error filter, to receive the CSI feedback. Example 28 includes the apparatus of example 26, wherein the transmit/receive circuitry is to set a transmit filter equal to the desired receive filter and to transmit the PDSCH transmission using the transmit filter.

Example 29 includes one or more computer-readable media having instructions that, when executed, cause a device to: preschedule a physical data shared channel ("PDSCH") data transmission for a user equipment ("UE"); schedule a preamble channel state information- reference signal ("PCSI-RS") for the UE; receive channel state information ("CSI") associated with the PCSI-RS from the UE; and schedule the PDSCH transmission for the UE based on the CSI.

Example 30 includes the one or more computer-readable media of example 29, wherein to preschedule the PDSCH transmission the device is to determine a resource allocation for the PDSCH transmission for the UE.

Example 31 includes the one or more computer-readable media of example 29 or 30, wherein to schedule the PCSI-RS the device is to transmit resource allocation information of the PCSI-RS in downlink control information ("DO") for the UE, wherein the instructions, when executed, further cause the device to transmit the PCSI-RS according to the resource allocation information of the PCSI-RS.

Example 32 includes the one or more computer-readable media of example 31, wherein the resource allocation information further identifies resources that are to be used to transmit CSI feedback that corresponds to the PCSI-RS.

Example 33 includes the one or more computer-readable media of any one of examples 29-32, wherein to schedule the PCSI-RS the device is to transmit the PCSI-RS according to pre-determined resource allocation list for the UE, wherein the pre-determined resource allocation list includes a plurality of resource allocation options for the UE.

Example 34 includes the one or more computer-readable media of any one of examples 29-33, wherein to schedule the PDSCH transmission the device is to determine a modulation and coding scheme ("MCS"), a rank, a precoding, or one or more sub-bands for the PDSCH transmission to the UE based on the CSI.

Example 35 includes the one or more computer-readable media of example 34, wherein the instructions, when executed, further cause the device to: transmit the PDSCH transmission to the UE based on the determined MCS, rank, precoding, or one or more sub-bands.

Example 36 includes one or more computer-readable media having instructions that, when executed, cause the device to: process a preamble channel state information-reference signal ("PCSI-RS") received on a first set of resources in a first subframe; measure CSI from the PCSI-RS; report the CSI in the first subframe; process a physical downlink shared channel ("PDSCH") data transmission received on the first set of resources in a second subframe.

Example 37 includes the one or more computer-readable media of example 36, wherein to process the PCSI-RS the device is to: determine resource allocation information of the PCSI-RS in downlink control information ("DCI"); and demodulate and decode the PCSI- RS based on the resource allocation information.

Example 38 includes the one or more computer-readable media of example 36 or 37, wherein to process the PCSI-RS the device is to: identify a pre-determined resource allocation list; and blindly decode transmissions on resources of the pre-determined resource allocation list until successful decoding the PCSI-RS.

Example 39 includes the one or more computer-readable media of any one of examples 36-38, wherein to measure the CSI from the PCSI-RS the device is to: estimate a desired channel from PCSI-RS after demodulation and decoding; and estimate interference based on the estimation of the desired channel.

Example 40 includes the one or more computer-readable media of example 39, wherein to measure the CSI from the PCSI-RS the device is to: determine a channel quality indicator ("CQI"), rank, precoding, or one or more subbands based on the estimation of the desired channel and the estimation of the interference.

Example 41 includes the one or more computer-readable media of any one of examples 36-38, wherein the CSI includes a channel quality indicator ("CQI"), rank, precoding matrix indicator ("PMI"), or one or more sub-bands.

Example 42 includes the one or more computer-readable media of any one of examples 36-41, wherein the instructions, when executed, further cause the device to: identify resource allocation information of the PDSCH based on downlink control information ("DCI"); identify MCS of the PDSCH based on the DCI; and process the PDSCH based on the resource allocation information and the MCS.

Example 43 includes one or more computer-readable media having instructions that, when executed, cause a device to: transmit a preamble channel state information-reference signal ("PCSI-RS") in a first subframe; receive channel state information ("CSI") feedback associated with the PCSI-RS in the first subframe; and transmit a physical downlink shared channel ("PDSCH") transmission in a second subframe based on the CSI feedback. Example 44 includes the one or more computer-readable media of example 43, wherein to receive the CSI feedback, the device is to determine a desired receive filter, using a minimum mean square error filter, to receive the CSI feedback.

Example 45 includes the one or more computer-readable media of example 43, wherein to transmit the PDSCH transmission, the device is to set a transmit filter equal to the desired receive filter and to transmit the PDSCH transmission using the transmit filter.

Example 46 includes one or more computer-readable media having instructions that, when executed, cause a device to: receive a preamble channel state information-reference signal ("PCSI-RS") in a first subframe; measure channel state information ("CSI") based on the PCSI-RS; and transmit the CSI in the first subframe.

Example 47 includes the one or more computer-readable media of example 46, wherein to receive the PCSI-RS, the device is further to: determine a desired receive filter, using a minimum mean square error filter, to receive the PCSI-RS.

Example 48 includes the one or more computer-readable media of example 47, wherein to transmit the CSI in the first subframe, the device is further to set a transmit filter equal to the desired receive filter and to transmit the CSI using the transmitter filter.

Example 49 includes a method comprising: prescheduling a physical data shared channel ("PDSCH") data transmission for a user equipment ("UE"); scheduling a preamble channel state information-reference signal ("PCSI-RS") for the UE; receiving channel state information ("CSI") associated with the PCSI-RS from the UE; and scheduling the PDSCH transmission for the UE based on the CSI.

Example 50 includes the method of example 49, wherein prescheduling the PDSCH transmission comprises determining a resource allocation for the PDSCH transmission for the UE.

Example 51 includes the method of example 49 or 50, wherein scheduling the PCSI-RS comprises transmitting resource allocation information of the PCSI-RS in downlink control information ("DCI") for the UE, the method further comprises transmitting the PCSI-RS according to the resource allocation information of the PCSI-RS.

Example 52 includes the method of example 51, wherein the resource allocation information further identifies resources that are to be used to transmit CSI feedback that corresponds to the PCSI-RS.

Example 53 includes the method of any one of examples 49-52, wherein scheduling the PCSI-RS comprises transmitting the PCSI-RS according to pre-determined resource allocation list for the UE, wherein the pre-determined resource allocation list includes a plurality of resource allocation options for the UE.

Example 54 includes the method of any one of examples 49-55, wherein scheduling the PDSCH transmission comprises determining a modulation and coding scheme ("MCS"), a rank, a precoding, or one or more sub-bands for the PDSCH transmission to the UE based on the CSI.

Example 55 includes the method of example 54, further comprising transmitting the PDSCH transmission to the UE based on the determined MCS, rank, precoding, or one or more sub-bands.

Example 56 includes a method comprising: processing a preamble channel state information-reference signal ("PCSI-RS") received on a first set of resources in a first subframe; measuring CSI from the PCSI-RS; reporting the CSI in the first subframe; and processing a physical downlink shared channel ("PDSCH") data transmission received on the first set of resources in a second subframe.

Example 57 includes the method of example 56, wherein processing the PCSI-RS comprises: determining resource allocation information of the PCSI-RS in downlink control information ("DO"); and demodulating and decode the PCSI-RS based on the resource allocation information.

Example 58 includes the method of example 56 or 57, wherein processing the PCSI-RS comprises: identifying a pre-determined resource allocation list; and blindly decoding transmissions on resources of the pre-determined resource allocation list until successful decoding the PCSI-RS.

Example 59 includes the method of any one of examples 56-58, wherein measuring the CSI from the PCSI-RS comprises: estimating a desired channel from PCSI-RS after demodulation and decoding; and estimating interference based on the estimation of the desired channel.

Example 60 includes the method of example 59, wherein measuring the CSI from the PCSI-RS comprises: determining a channel quality indicator ("CQI"), rank, precoding, or one or more subbands based on the estimation of the desired channel and the estimation of the interference.

Example 61 includes the method of any one of examples 56-58, wherein the CSI includes a channel quality indicator ("CQI"), rank, precoding matrix indicator ("PMI"), or one or more sub-bands. Example 62 includes the method of any one of examples 56-61, wherein the instructions, when executed, further cause the device to: identify resource allocation information of the PDSCH based on downlink control information ("DCI"); identify MCS of the PDSCH based on the DCI; and process the PDSCH based on the resource allocation information and the MCS.

Example 63 includes a method comprising: transmitting a preamble channel state information-reference signal ("PCSI-RS") in a first subframe; receiving channel state information ("CSI") feedback associated with the PCSI-RS in the first subframe; and transmitting a physical downlink shared channel ("PDSCH") transmission in a second subframe based on the CSI feedback.

Example 66 includes the method of example 63, wherein to receive the CSI feedback, the device is to determine a desired receive filter, using a minimum mean square error filter, to receive the CSI feedback.

Example 65 includes the method of example 63, wherein to transmit the PDSCH transmission, the device is to set a transmit filter equal to the desired receive filter and to transmit the PDSCH transmission using the transmit filter.

Example 66 includes a method comprising: receiving a preamble channel state information-reference signal ("PCSI-RS") in a first subframe; measuring channel state information ("CSI") based on the PCSI-RS; and transmitting the CSI in the first subframe. Example 67 includes the method of example 66, wherein receiving the PCSI-RS comprises: determining a desired receive filter, using a minimum mean square error filter, to receive the PCSI-RS.

Example 68 includes the method of example 67, wherein transmitting the CSI in the first subframe comprises: setting a transmit filter equal to the desired receive filter and transmitting the CSI using the transmitter filter.

Example 69 includes an apparatus comprising means to perform one or more elements of a method described in or related to any of examples 49-69, or any other method or process described herein.

Example 70 includes one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of a method described in or related to any of examples 49-69, or any other method or process described herein. Example 71 includes an apparatus comprising logic, modules, or circuitry to perform one or more elements of a method described in or related to any of examples 49-69, or any other method or process described herein.

Example 72 includes an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform a method described in or related to any of examples 49-69, or portions thereof.

Claims

CLAIMS What is claimed is:

1. One or more computer-readable media having instructions that, when executed, cause a device to:

preschedule a physical data shared channel ("PDSCH") data transmission for a user equipment ("UE");

schedule a preamble channel state information-reference signal ("PCSI-RS") for the UE; receive channel state information ("CSI") associated with the PCSI-RS from the UE; and schedule the PDSCH transmission for the UE based on the CSI.

2. The one or more computer-readable media of claim 1, wherein to preschedule the PDSCH transmission the device is to determine a resource allocation for the PDSCH transmission for the UE.

3. The one or more computer-readable media of claim 1 or 2, wherein to schedule the PCSI-RS the device is to transmit resource allocation information of the PCSI-RS in downlink control information ("DO") for the UE, wherein the instructions, when executed, further cause the device to transmit the PCSI-RS according to the resource allocation information of the PCSI-RS.

4. The one or more computer-readable media of claim 3, wherein the resource allocation information further identifies resources that are to be used to transmit CSI feedback that corresponds to the PCSI-RS.

5. The one or more computer-readable media of claim 1 or 2, wherein to schedule the PCSI-RS the device is to transmit the PCSI-RS according to a pre-determined resource allocation list for the UE, wherein the pre-determined resource allocation list includes a plurality of resource allocation options for the UE.

6. The one or more computer-readable media of claim 1 or 2, wherein to schedule the PDSCH transmission the device is to determine a modulation and coding scheme ("MCS"), a rank, a precoding, or one or more sub-bands for the PDSCH transmission to the UE based on the CSI.

7. The one or more computer-readable media of claim 6, wherein the instructions, when executed, further cause the device to: transmit the PDSCH transmission to the UE based on the determined MCS, rank, precoding, or one or more sub-bands.

8. One or more computer-readable media having instructions that, when executed, cause a device to:

process a preamble channel state information-reference signal ("PCSI-RS") received on a first set of resources in a first subframe;

measure CSI from the PCSI-RS;

report the CSI in the first subframe;

process a physical downlink shared channel ("PDSCH") data transmission received on the first set of resources in a second subframe.

9. The one or more computer-readable media of claim 8, wherein to process the PCSI-RS the device is to:

determine resource allocation information of the PCSI-RS in downlink control information ("DCI"); and

demodulate and decode the PCSI-RS based on the resource allocation information.

10. The one or more computer-readable media of claim 8 or 9, wherein to process the PCSI-RS the device is to:

identify a pre-determined resource allocation list; and

blindly decode transmissions on resources of the pre-determined resource allocation list until successful decoding of the PCSI-RS.

11. The one or more computer-readable media of claim 8 or 9, wherein to measure the CSI from the PCSI-RS the device is to:

estimate a desired channel from PCSI-RS after demodulation and decoding; and estimate interference based on the estimation of the desired channel.

12. The one or more computer-readable media of claim 11, wherein to measure the CSI from the PCSI-RS the device is to: determine a channel quality indicator ("CQI"), rank, precoding, or one or more subbands based on the estimation of the desired channel and the estimation of the interference.

13. The one or more computer-readable media of claim 8 or 9, wherein the CSI includes a channel quality indicator ("CQI"), rank, precoding matrix indicator ("PMI"), or one or more sub-bands.

14. The one or more computer-readable media of claim 8 or 9, wherein the instructions, when executed, further cause the device to:

identify resource allocation information of the PDSCH based on downlink control information ("DCI");

identify MCS of the PDSCH based on the DCI; and

process the PDSCH based on the resource allocation information and the MCS.

15. An apparatus compri sing :

scheduler circuitry to schedule a first subframe to include preamble channel state information-reference signal ("PCSI-RS");

transmit/receive circuitry to transmit the PCSI-RS in a first subframe based on the schedule of the first subframe; and receive channel state information ("CSI") feedback associated with the PCSI-RS in the first subframe;

wherein the scheduler circuitry is to schedule a second subframe to include a physical downlink shared channel ("PDSCH") transmission based on the CSI feedback, and the transmit/receive circuitry is to transmit the PDSCH transmission in the second subframe based on the schedule of the second subframe.

16. The apparatus of claim 15, wherein the transmit/receive circuitry is to determine a desired receive filter, using a minimum mean square error filter, to receive the CSI feedback.

17. The apparatus of claim 16, wherein the transmit/receive circuitry is to set a transmit filter equal to the desired receive filter and to transmit the PDSCH transmission using the transmit filter.

18. One or more computer-readable media having instructions that, when executed, cause a device to:

receive a preamble channel state information-reference signal ("PCSI-RS") in a first subframe;

measure channel state information ("CSI") based on the PCSI-RS; and

transmit the CSI in the first subframe.

19. The one or more computer-readable media of claim 18, wherein to receive the PCSI- RS, the device is further to:

determine a desired receive filter, using a minimum mean square error filter, to receive the PCSI-RS.

20. The one or more computer-readable media of claim 19, wherein to transmit the CSI in the first subframe, the device is further to

set a transmit filter equal to the desired receive filter and to transmit the CSI using the transmit filter.

21. An apparatus comprising:

means to preschedule a physical data shared channel ("PDSCH") data transmission for a user equipment ("UE");

means to schedule a preamble channel state information-reference signal ("PCSI-RS") for the UE;

means to receive channel state information ("CSI") associated with the PCSI-RS from the UE; and

means to schedule the PDSCH transmission for the UE based on the CSI.

22. The apparatus of claim 21, wherein means to preschedule the PDSCH transmission is to determine a resource allocation for the PDSCH transmission for the UE.

23. The apparatus of claim 21 or 22, wherein means to schedule the PCSI-RS the apparatus is to transmit resource allocation information of the PCSI-RS in downlink control information ("DO") for the UE, and apparatus further comprises:

means to transmit the PCSI-RS according to the resource allocation information of the

PCSI-RS.

24. The apparatus of claim 23, wherein the resource allocation information further identifies resources that are to be used to transmit CSI feedback that corresponds to the PCSI-RS.

25. The apparatus of claim 21 or 22, wherein means to schedule the PCSI-RS is to transmit the PCSI-RS according to pre-determined resource allocation list for the UE, wherein the pre-determined resource allocation list includes a plurality of resource allocation options for the UE.