WO2017165450A1

WO2017165450A1 - Orthogonal multiplexing techniques for demodulation reference signals

Info

Publication number: WO2017165450A1
Application number: PCT/US2017/023456
Authority: WO
Inventors: Alexei Davydov; Gregory V. Morozov; Hyejung Jung; Victor SERGEEV; Yushu Zhang; Yuan Zhu; Wenting CHANG
Original assignee: Intel Corporation
Priority date: 2016-03-22
Filing date: 2017-03-21
Publication date: 2017-09-28
Also published as: EP3433965A1

Abstract

Techniques for orthogonal multiplexing Demodulation Reference Signals (DM-RS) can include transmitting the DM-RS based on a resource allocation and transmitting the data on a subset. Alternatively, the DM-RSs can be transmitted on a subset of subcarriers in the resource allocation. In addition, the DM-RSs of a given UE can be combined utilizing Frequency Division Multiplexing (FDM) with DM-RS of other UEs. The DM-RS of the given UE can also be combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with the DM-RSs of other UEs.

Description

ORTHOGONAL MULTIPLEXING TECHNIQUES FOR DEMODULATION

REFERENCE SIGNALS

BACKGROUND

[0001] Wireless communication technology uses various standards and protocols to transmit data between a node (e.g. a transmission station) and a wireless device (e.g., a mobile device). As wireless mobile communication technology continues to develop, greater bandwidth is needed for the increasing amount of data transmitted from an increasing number of devices. The types of devices using wireless

communication technology is increasing from traditional cell phones, tablet computers and laptop computers, to include devices such as smart meters, connected appliances, vehicular infotainment system, self-driving vehicles, wearable devices, remote sensing devices and the like. The devices can be mobile, or deployed in fixed locations, and can be operating from open spaces, inside offices and homes, deep in basements, and the like. To service the growing number of uses for wireless communication technology, there is a growing need for wireless communication technologies that provide for improved spectrum utilization.

[0002] In one aspect, an uplink Demodulation Reference Signal (DM-RS) is utilized in uplink channel estimation for determining accuracy, reliability and throughput of data communicated from a User Equipment (UE) to a Radio Access Network Nodes (RAN nodes). Currently, DM-RS support for multi-user multiple input multiple output (MU-MIMO) transmission on the physical uplink shared channel (PUSCH) is limited.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Features and advantages of the disclosure will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the disclosure; and, wherein:

FIG. 1 illustrates an architecture of a wireless network with various components of the network in accordance with some embodiments;

FIG. 2 illustrates an uplink radio frame structure in accordance with some embodiments; FIG. 3 illustrates the uplink data and DM-RS structure of the Physical Uplink Shared Channel (PUSCH) in accordance with some embodiments;

FIG. 4 illustrates the resource allocation for uplink data and DM-RS structure of the PUSCH in accordance with some embodiments;

FIG. 5 depicts a process for resource allocation for uplink and DM-RS of the PUSCH in accordance with some embodiments;

FIG. 6 illustrates the resource allocation for uplink data and DM-RS structure of the PUSCH in accordance with some embodiments;

FIG. 7 depicts a process for resource allocation for uplink and DM-RS of the PUSCH in accordance with some embodiments;

FIG. 8 illustrates one simulation results for the intra-cell interference to total interference plus noise ratio;

FIG. 9 illustrates a DM-RS pattem in one Resource Block (RB) in accordance with some embodiments;

FIG. 10 illustrates example components of a device in accordance with some

embodiments;

FIG. 11 illustrates example interfaces of baseband circuitry in accordance with some embodiments;

FIG. 12 is an illustration of a control plane protocol stack in accordance with some embodiments;

FIG. 13 is an illustration of a user plane protocol stack in accordance with some embodiments;

FIG. 14 illustrates components of a core network in accordance with some embodiments; FIG. 15 is a block diagram illustrating components, according to some example embodiments; and

FIG. 16 illustrates a diagram of example components of a UE in accordance with some embodiments.

[0004] Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the technology is thereby intended. DETAILED DESCRIPTION

[0005] Before the present technology is disclosed and described, it is to be understood that this technology is not limited to the particular structures, process actions, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular examples only and is not intended to be limiting. The same reference numerals in different drawings represent the same element. Numbers provided in flow charts and processes are provided for clarity in illustrating actions and operations and do not necessarily indicate a particular order or sequence.

DEFINITIONS

[0006] As used herein, the term "User Equipment (UE)" refers to a computing device capable of wireless digital communication such as a smart phone, a tablet computing device, a laptop computer, a multimedia device such as an iPod Touch^®, or other type computing device that provides data, text, or voice communication. The term "User Equipment (UE)" can also refer to a wireless device that is connectable to an electrical sensor, instrumentation, or another type of digital circuit, wherein the wireless device can communicate data from or receive data for the electrical sensor,

instrumentation, or digital circuit to another wireless device (i.e. machine to machine (M2M)) or a person. The term "User Equipment (UE)" may also be refer to as a "mobile device," "wireless device," of "wireless mobile device."

[0007] As used herein, the term "Radio Access Network node," "RAN node," "Evolved NodeB," "eNodeB," or "eNB," refers to a device or configured node of a mobile phone network that communicates wirelessly with UEs.

[0008] As used herein, the term "cellular telephone network' or "Long Term

Evolved (LTE)" refers to wireless technology developed by the Third Generation Partnership Project (3GPP).

EXAMPLE EMBODIMENTS

[0009] An initial overview of technology embodiments is provided below and then specific technology embodiments are described in further detail later. This initial summary is intended to aid readers in understanding the technology more quickly but is not intended to identify key features or essential features of the technology nor is it intended to limit the scope of the claimed subject matter.

[0010] In one aspect, a wireless system can include one or more UE devices and one or more RAN nodes. The UE can be configured by a RAN node to encode data and DM-RSs based on one or more allocation parameters. When configured, the UE can encode a DM-RS in one or more RBs in a PUSCH based on an allocation of RBs in one or more subframes for uplink transmission to a RAN node. The UE can also encode data in the PUSCH based on an allocation of a subset of the RBs for uplink transmission to the RAN node.

[0011] In another aspect, the UE can be configured by a RAN node to encode data and DM-RSs based on one or more allocation parameters. When configured, the UE can encode a DM-RS in each of the plurality of subsets of subcarriers in one or more RBs based on the allocation of RBs for uplink transmission to a RAN node. The UE can also encode data in the PUSCH based on an allocation of the RBs for uplink transmission to the RAN node.

[0012] In an additional aspect, the DM-RS of the UE can be combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS to reduce intra-cell interference. In addition, a resource index for a Physical Hybrid-automatic repeat request Indicator Channel (PHICH) can be based on a starting resource block index of the resource block, a cyclic shift (n_DMRS) and a starting subcarrier (x). In another aspect, the DM-RS of the UE can be combined utilizing FDM and a cross-subframe orthogonal cover code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

[0013] FIG. 1 illustrates an architecture of a wireless network with various components of the network in accordance with some embodiments. A system 100 is shown to include a UE 101 and a UE 102. The UEs 101 and 102 are illustrated as smartphones (i.e., handheld touchscreen mobile computing devices 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, laptop computers, desktop computers, wireless handsets, or any computing device including a wireless

communications interface. In some embodiments, any of the UEs 101 and 102 can comprise an Internet of Things (IoT) UE, which can comprise 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 communications (MTC) for (machine initiated) exchanging data with an MTC server and/or device via a public land mobile network (PLMN), Proximity -Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. An IoT network describes interconnecting uniquely identifiable embedded computing devices (within the internet infrastructure) having short-lived connections, in addition to background applications (e.g., keep-alive messages, status updates, etc.) executed by the IoT UE.

[0014] The UEs 101 and 102 are configured to access a RAN— in this embodiment, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) 110. The UEs 101 and 102 utilize connections 103 and 104, respectively, each of which comprises a physical

communications interface or layer (discussed in further detail below); in this example, the connections 103 and 104 are illustrated as an air interface to enable communicative coupling, and 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, and the like.

[0015] In this embodiment, the UEs 101 and 102 may further directly exchange communication data via a ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH).

[0016] The UE 102 is shown to be configured to access an access point (AP) 106 via connection 107. The connection 107 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP 106 would comprise a wireless fidelity (WiFi) router. [0017] The E-UTRAN 110 can include one or more access points that enable the connections 103 and 104. These access points can be referred to as access nodes, base stations (BSs), NodeBs, RAN nodes, RAN nodes, and so forth, and can comprise ground stations (i.e., terrestrial access points) or satellite access points providing coverage within a geographic area (i.e., a cell). The E-UTRAN 110 may include one or more RAN nodes 111 for providing macrocells and one or more RAN nodes 112 for providing femtocells or picocells (i.e., cells having smaller coverage areas, smaller user capacity, and/or higher bandwidth compared to macrocells).

[0018] Any of the RAN nodes 111 and 112 can terminate the air interface protocol and can be the first point of contact for the UEs 101 and 102. In some embodiments, any of the RAN nodes 111 and 112 can fulfill various logical functions for the E-UTRAN 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.

[0019] In accordance with some embodiments, the UEs 101 and 102 can be configured to communicate using Orthogonal Frequency -Division Multiplexing (OFDM) communication signals with each other or with any of the RAN nodes 111 and 112 over a multicarrier communication channel in accordance various communication techniques, such as an Orthogonal Frequency -Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., 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.

[0020] In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 111 and 112 to the UEs 101 and 102, 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 resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this represents the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks.

[0021] The physical downlink shared channel (PDSCH) carries user data and higher-layer signaling to the UEs 101 and 102. The physical downlink control channel (PDCCH) carries information about the transport format and resource allocations related to the PDSCH channel, among other things. It also informs the UEs 101 and 102 about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE 102 within a cell) is performed at any of the RAN nodes 111 and 112 based on channel quality information fed back from any of the UEs 101 and 102, and then the downlink resource assignment information is sent on the PDCCH used for (i.e., assigned to) each of the UEs 101 and 102.

[0022] The PDCCH uses control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex- valued symbols are first organized into quadruplets, which are then permuted using a sub- block inter-leaver for rate matching. Each PDCCH is transmitted using one or more of these CCEs, where each CCE corresponds to nine sets of four physical resource elements known as resource element groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols are mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=l, 2, 4, or 8).

[0023] The E-UTRAN 110 is shown to be communicatively coupled to a core network— in this embodiment, an Evolved Packet Core (EPC) network 120 via an SI interface 113. In this embodiment, the SI interface 113 is split into two parts: the Sl-U interface 114, which carries traffic data between the RAN nodes 111 and 112 and the serving gateway (S-GW) 122, and the Sl-MME interface 115, which is a signaling interface between the RAN nodes 111 and 112 and the mobility management entities (MMEs) 121.

[0024] In this embodiment, the EPC network 120 comprises the MMEs 121, the S-GW 122, the Packet Data Network (PDN) Gateway (P-GW) 123, and a home subscriber server (HSS) 124. The MMEs 121 are similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 121 manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 124 comprises a database for network users, including subscription-related information to support the network entities' handling of

communication sessions. The EPC network 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 124 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

[0025] The S-GW 122 terminates the SI interface 113 towards the E-UTRAN

110, and routes data packets between the E-UTRAN 110 and the EPC network 120. In addition, the S-GW 122 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other

responsibilities may include lawful intercept, charging, and some policy enforcement.

[0026] The P-GW 123 terminates an SGi interface toward a PDN. The P-GW

123 routes data packets between the EPC network 123 and external networks such as a network including the application server 130 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 125. Generally, the application server 130 is an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this embodiment, the P-GW 123 is shown to be communicatively coupled to an application server 130 via an IP communications interface 125. The application server 130 can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 101 and 102 via the EPC network 120.

[0027] The P-GW 123 may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF) 126 is the policy and charging control element of the EPC network 120. In a non-roaming scenario, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a User Equipment's (UE) Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 126 may be communicatively coupled to the application server 130 via the P-GW 123. The application server 130 may signal the PCRF 126 to indicate a new service flow and selecting the appropriate Quality of Service (QoS) and charging parameters. The PCRF 126 may provision this rule into a Policy and Charging

Enforcement Function (PCEF) (not shown) with the appropriate traffic flow template (TFT) and QoS class of identifier (QCI), which commences the QoS and charging as specified by the application server.

[0028] FIG. 2 illustrates an uplink radio frame structure in accordance with some embodiments. In the example, a radio frame 200 of a signal used to transmit control information or data can be configured to have a duration, Tf, of 10 milliseconds (ms). Each radio frame can be segmented or divided into ten subframes 210i that are each 1 ms long. Each subframe can be further subdivided into two slots 220a and 220b, each with a duration, Tsiot, of 0.5 ms. Each slot for a component carrier (CC) used by the wireless device and the node can include multiple resource blocks (RBs) 230a, 230b, 230i, 230m, and 230n based on the CC frequency bandwidth. Each RB (physical RB or PRB) 230i can include 12 - 15 kHz subcarriers 236 (on the frequency axis) and 6 or 7 SC-FDMA symbols 232 (on the time axis) per subcarrier. The RB can use seven SC-FDMA symbols if a short or normal cyclic prefix is employed. The RB can use six SC-FDMA symbols if an extended cyclic prefix is used. The resource block can be mapped to 84 resource elements (REs) 240i using short or normal cyclic prefixing, or the resource block can be mapped to 72 REs (not shown) using extended cyclic prefixing. The RE can be a unit of one SC-FDMA symbol 242 by one subcarrier (i.e., 15kHz) 246. Each RE can transmit two bits 250a and 250b of information in the case of quadrature phase-shift keying (QPSK) modulation. Other types of modulation may be used, such as 16 quadrature amplitude modulation (QAM) or 64 QAM to transmit a greater number of bits in each RE, or bi-phase shift keying (BPSK) modulation to transmit a lesser number of bits (a single bit) in each RE. The RB can be configured for an uplink transmission from the wireless device to the node.

[0029] In one aspect, reference signals (RS) can be transmitted by SC-FDMA symbols via resource elements in the resource blocks. Reference signals (or pilot signals or tones) can be a known signal used for various reasons, such as to synchronize timing, estimate a channel, and/or reduce noise in the channel. Reference signals can be received and transmitted by wireless devices and nodes. Different types of reference signals (RS) can be used in a RB. For example, in LTE systems, uplink reference signal types can include a sounding reference signal (SRS) and a UE-specific reference signal (UE- specific RS or UE-RS) or a DM-RS .

[0030] In one aspect, uplink subframes can include 14 SC-FDMA symbols, wherein 2 symbols can be allocated for transmission of DM-RS and the remaining 12 symbols for data transmission on the PUSCH. In some instances, the last SC-FDMA symbol of the uplink subframe can also be used for transmission of Sounding Reference Signals (SRS).

[0031] The PUSCHs for Long Term Evolved (LTE) communication can be based on SC-FDMA, where each symbol can be Discrete Fourier Transform (DFT) pre- coded in the frequency domain prior to subcarrier modulation. The DM-RSs can be used to facilitate channel estimation at the serving cell RAN node 111, 112. The uplink DM- RSs in LTE can be transmitted in the middle of each slot (i.e., on SC-FDMA symbols with index 3 and 11) and modulated using Zadoff-Chu sequence (e.g., base sequence) except for the small resource allocation sizes of 1 or 2 RBs.

[0032] DM-RSs associated with the PUSCH can be used by the RAN node 111, 112 to perform channel estimation and allow for coherent demodulation of the received signal. The DM-RSs can be time-multiplexed with data, whereas in the downlink there is both time and frequency division multiplexing. The multiplexing can be performed to maintain the single-carrier nature of the SC-FDMA signal, which ensures that data carriers are contiguous.

[0033] The DM-RSs can be generated using a base sequence denoted by More specifically can be used to denote the PUSCH DM-RS sequence

and can be defined by Equation 1,

It is desired that the DM-RS sequences have small power variations in time and frequency, resulting in high power amplifier efficiency and comparable channel estimation quality for all frequency components. Zadoff-Chu sequences are good candidates because they exhibit constant power in time and frequency. However, there are a limited number of Zadoff-Chu sequences, and therefore, they are not suitable on their own.

[0034] The DM-RS can be defined by a cyclic shift, a, of a base sequence, r. The base sequence, 4, can be expressed in Equation 2,

Wherein n

and M_RSSC is the length of the reference signal sequence, wherein 9 is the base sequence group number, and wherein V = 0, 1 is the

sequence number within the group and applies to reference signals of length greater than 6 RB.

[0035] A phase rotation in the frequency domain (pre-Inverse Fast Fourier

Transform (IFFT) in the OFDM modulation) is equivalent to a cyclic shift in the time domain (post-IFFT in the OFDM) modulation). For frequency non-selective channels over the 12 subcarriers of a RB, it is possible to achieve orthogonality between DM-RS generated from the same base sequence if a = m*pi/6 for m = 0, 1, ... , 1 1, and assuming the DM-RSs are synchronized in time.

[0036] The orthogonality can be exploited to transmit DM-RS at the same time, using the same frequency resources without mutual interference. Generally, the DM-RS generated from different base sequences will not be orthogonal; however, they will present low cross-correlation properties. To maximize the number of available Zadoff- Chu sequences, a prime length sequence is used. The minimum sequence length in the uplink can be 12, the number of subcarriers in a RB, which is not a prime number.

Therefore, Zadoff-Chu sequences are not suitable by themselves. There are effectively two types of base reference sequences. First, those with a sequence length greater than or equal to 36 (e.g., spanning 3 or more RBs), which use a cyclic extension of Zadoff-Chu sequences. Second, those with a sequence length of less than or equal to 36 (spanning 2 RBs), which use a special QPSK sequence. [0037] There can be a total of 30 sequence groups, u£ {0, 1, ... , 29}, each containing one sequence for length less than or equal to 60. This corresponds to transmission bandwidth of 1, 2, 3, 4 and 5 resource blocks. Additionally, there can be two sequences (one for v = 0 or 1) for length greater than or equal to 72, corresponding to transmission bandwidths of 6 RB or more. Note that not all values of m are allowed, where m is the number of RBs used for transmission. The values for m that are the product of a power of 2, 3 and 5 are valid, as shown in Equation 3,

The reason for this restriction is that the DFT sizes of the SC-FDMA precoding operation are limited to values which are the product of powers of 2, 3 and 5. The DFT operation can span more than one RB, and because each RB has 12 subcarriers, the total number of subcarriers fed to the DFT will be 12m. Because the result of 12m has to be the product of power of 2, 3 and 5, it is implied that the number of RBs themselves be the product of power of 2, 3 and 5. Therefore, values of m such as 7, 11, 14, 19, ... are not valid.

[0038] For a given time slot, the uplink reference signal sequences to use within a cell can be taken from one specific sequence group. The same group used for all slots may be known as a fixed assignment. On the other hand, if the group number u varies for all slots within a cell, it may be known as group hopping.

[0039] The PUSCH DM-RS can be mapped to the 4^th SC-FDMA symbol of the slot during normal cyclic prefix and to every 3^rd SC-FDMA symbol during extended prefix. The SC-FDMA symbols for DM-RS can be shared by multiple UE to support Multi-User Multiple Input Multiple Output (MU-MIMO). To minimize interference between DM-RSs of different UEs, different cyclic shifts of the base sequence can be used, which is equivalent to applying DFT orthogonal complimentary codes on top of Zadoff-Chu sequence. It should be noted that orthogonal multiplexing of DM-RS is possible when the DM-RS sequences have the same lengths, or the resource allocation sizes of the UEs are the same, and fully overlaps with each other. Support of orthogonal DM-RS multiplexing for PUSCH without aligned resource allocations, is provided by using time domain orthogonal complimentary code (OCC), which is applied across two DM-RS symbols of one UL subframe. Because the number of DM-RSs in the UL subframe is limited to 2 symbols, the maximum number of orthogonal DM-RSs with unequal allocation does not exceed 2.

[0040] FIG. 3 illustrates the uplink data and DM-RS structure of the PUSCH in accordance with some embodiments. The SC-FDMA symbols for DM-RS can be shared by multiple UE 310, 320, 330, for example to support MU-MIMO. To minimize interference between DM-RSs of different UEs, different cyclic shifts of the base sequence can be used, which is equivalent to applying DFT orthogonal complimentary codes on top of the Zadoff-Chu sequence. It should be noted that orthogonal

multiplexing of DM-RSs is possible when the DM-RS sequences have the same length, or the resource allocations sizes of UEs are the same, and fully overlap with each other. Support of orthogonal DM-RS multiplexing for PUSCH with non-aligned resource allocations, is provided by using a time domain cover code, which is applied across two DM-RS symbols of one uplink subframe. Because the number of DM-RSs in the uplink subframe are limited to 2 symbols, the maximum number of orthogonal DM-RSs with unequal resource allocated does not exceed 2. For example, for the resource allocation in FIG. 3, the orthogonal DM-RS port multiplexing would not be possible.

[0041] For Full Dimension Multiple Input and Multiple Output (FD-MIMO) scenarios, support of the high order MU-MIMO for the uplink with partial overlapping resource allocations of the co-scheduled US provides increased flexibility of the uplink scheduling. The uplink DM-RS in accordance with FIG. 3 does not provide such capability.

[0042] FIG. 4 illustrates the resource allocation for uplink data and DM-RS structure of the PUSCH in accordance with some embodiments. The resource allocation for the data can be a subset of the resource allocation for DM-RS transmission on the PUSCH. The RAN node can advantageously align resource allocation of different UEs for DM-RS. Different cyclic shift or Orthogonal complimentary code (OCC) can then be used to achieve orthogonality between DM-RS. An additional resource allocation field for DM-RS may be introduced. The indicated resource allocation of DM-RS 410, 420, 430 should fully cover the resource allocation of the data 440, 450, 460 on the PUSCH.

[0043] FIG. 5 depicts a process for resource allocation for uplink data and DM-

RS transmission on the PUSCH in accordance with some embodiments. The process can be performed by an apparatus of the UE including memory and one or more processor configured to support channel estimation for communicating data to a RAN node. In one aspect, one or more parameters received from a RAN node can be decoded by a User Equipment (UE). The one or more parameters can include an allocation to encode DM- RSs in one or more RBs and an allocation to encode data in a subset of the RBs 510. In one instance, the one or more parameters including the allocation to encode the DM-RS in the one or more RBs and the allocation to encode the data in the subset of the RBs can be included in an additional resource allocation field of a radio resource control (RRC) signaling received by the UE from the RAN node. For example, the parameters can include the RBs for DM-RS transmission, the cyclic shift, and the OCC. In one instance, a starting subcarrier (x) of the DM-RS in the RB can be configured by DCI or higher layer signaling. In one aspect, the encoding of RBs by the UE can be configured based on the one or more parameters including the allocation to encode the DM-RSs in the one or more RBs and the allocation to encode the data in the subset of the RBs 520.

[0044] In one aspect, a DM-RS can be encoded in one or more RBs based on an allocation of RBs in one or more subframes for the uplink transmission to a RAN node 530. In one aspect, data in the PUSCH can be encoded based on the allocation of a subset of the RBs for uplink transmission to the RAN node 540. In one instance, the allocation to encode the DM-RSs in the one or more resource blocks by the UE is aligned with allocations to encode DM-RSs on the one or more resource blocks by a plurality of other UEs. In one instance, different orthogonal complimentary codes are used to encode the DM-RS in the one or more resource blocks by the UE and DM-RSs in the one or more resource blocks by the plurality of other UEs. In one instance, different cyclic shifts are used to encode the DM-RS in the one or more resource blocks by the UE and DM-RSs in the one or more resource blocks by the plurality of other UEs.

[0045] FIG. 6 illustrates the resource allocation for uplink data and DM-RS structure of the PUSCH in accordance with some embodiments. In one aspect, the DM- RS can be mapped to each Xth subcarrier (e.g., X=4). The orthogonality between DM- RS for the partially overlapping resource allocations can be achieved by using a different subcarrier shift. The subcarrier mapping step X can be signaled by Radio Resource Control (RRC) and the subcarrier shift 0, ... , X-l can be dynamically signaled in the Downlink Control Information (DCI). [0046] In a given uplink subframe the transmission communication channels can be determined according to Equation 4,

where the is indicated in the DCI, c(2n_s) is a pseudo-random

sequence, which can be initialized using RRC signaling every N-th subframe, wherein N can be 20 or 40, n_s can be the slot index and RFP can be the maximum number of communication channels supported by DM-RS (e.g., 2). In another example, the communication channel index can be determined for each slot by replacing 2n_s in Equation 4 with

[0047] FIG. 7 depicts a process for resource allocation for uplink data and DM- RS transmission on the PUSCH in accordance with some embodiments. The process can be performed by an apparatus of the UE including memory and one or more processor configured to support channel estimation for communicating data to a RAN node. In one aspect, one or more parameters received from a RAN node can be decoded by a User Equipment (UE). The one or more parameters can include an allocation to encode DM- RSs in each of a plurality of subsets of subcarriers in one or more RBs 710. In one instance, the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks can be included in an additional resource allocation field of a RRC signaling received by the UE from the RAN node. For example, the parameters can include the RBs for DM-RS transmission, the cyclic shift, and the OCC. In one instance, a starting subcarrier (x) of the DM-RS in the resource block can be configured by downlink control information (DCI) or higher layer signaling. In one aspect, the encoding of RBs by the UE can be configured based on the one or more parameters including the allocation to encode the DM-RS in the one or more RBs and the allocation to encode the data in the subset of the RBs 720.

[0048] In one aspect, a DM-RS can be encoded in each of the plurality of subsets of subcarriers in the one or more RBs in the physical uplink shared channel (PUSCH) based on the allocation of resource blocks for uplink transmission to the RAN node 730. In one aspect, data in the PUSCH can be encoded based on the allocation of the RBs for uplink transmission to the RAN node 740. In one instance, encoding the DM-RS in each of the plurality of subset of subcarriers in one or more RBs can be based on a frequency shift, a decimation factor, cyclic shift and an OCC. In one instance, the decimator factor can include 2 or 4 and can indicate that the DM-RS is transmitted in each of the plurality of subsets of subcarriers within the allocation of the resource blocks. In one instance, the cyclic frequency shift can be in a range of 0, 1, ... , X-l and can include the set of the decimated subcarriers for encoding the DM-RS. In one instance, a subcarrier mapping is signaled by RRC and the subcarrier shift, 0, ... , X-l, is dynamically signaled in a DCI.

[0049] In one instance, a comb can be based on Equation 4. In another instance, the comb can be based on Equation 5,

where the is indicated in the DCI, c(n_s) is a pseudo-random

sequence, which can be initialized using RRC signaling every N-th subframe, wherein N can be 20 or 40, n_s can be the slot index and RFP can be the maximum number of communication channels supported by DM-RS.

[0050] In one aspect, in Full Dimension Multiple Input and Multiple Output (FD-MIMO), in which a two-dimension (2D) antenna array may be used, the number of transmitting resource units (TXRU) may be increased to support the non-precoded Channel State Information Reference Signal (CSI-RS). Meanwhile, the number of receiving resource units (RXRU) may also get increased, so that it is possible to support a higher uplink MU-MIMO dimension. As the MU-MIMO dimension becomes large, the intra-cell interference may become more severe. FIG. 8 illustrates one simulation results for the intra-cell interference to total interference plus noise ratio, from which it can be observed that the intra-cell interference could become dominant in high MU-MIMO dimension case. To reduce the intra-cell interference, generally an orthogonal DM-RS pattern can be used. Based on current DM-RS structure, the DM-RS for MU-MIMO UEs may not be orthogonal if different size of RBs are allocated to different UEs. Hence it can be necessary to design more orthogonal DM-RS sequences. [0051] In one aspect, the DM-RSs for different UEs in a MU-MIMO operation are generated with different cyclic shifts, and different OCC may be used. In one aspect, there are a total of 12 cyclic shifts, from which 8 cyclic shifts can be used in one subframe, as well as second order OCCs that are defined. The DM-RS sequence may not be orthogonal if different RB assignments are used for the MU-MIMO UEs. Therefore, to produce more orthogonal DM-RS, there can be two options: one is to utilize a

Frequency Division Multiplex (FDM) based DM-RS, for example, comb based DM-RS pattern; the other is to utilize a higher OCC degree.

[0052] In one aspect, for a comb based DM-RS pattern, the DM-RS can be mapped to every T subcarriers within the granted RBs in symbol 3 for normal Cyclic

Prefix (CP) and symbol 2 for extended CP in one slot, where T can be pre-defined by the system, or indicated by the uplink grant or higher layer signaling, e.g. 7=2. The starting subcarriers x (x £ [0, T — 1]) can be indicated by the uplink grant or higher layer signaling. [0053] The sequence of the DM-RS can be defined by Equation 6,

wherein and wherein T denotes the subcarrier, x denotes

the starting subcarrier, μ denotes a layer index, indicates a number of subcarriers in

the resource blocks, refers to an orthogonal complimentary code, and

represent a Zadoff-Chu sequence.

[0054] FIG. 9 illustrates one example for the DM-RS pattern in one RB, where UE 1 and 2 can be granted different comb patterns. Then the mutual-interference for DM- RS can be reduced so that the channel estimation performance could be increased.

[0055] In another aspect, the resource index for PHICH may be determined by the starting RB index, cyclic shifts and the starting subcarrier x. For example, a PHICH resource can be indicated by group index The

group index can be calculated according to Equation 7,

The sequence index can be calculated according to Equation 8,

wherein, is ^a function of a transport block (TB) index and a first physical resource

block (PRB) index for PUSCH, n_DMRS is a function of a cyclic shift and an OCC index defined in a DCI, x denotes the starting subcarrier, is a spreading factor size used

for modulation,

1 at subframe 4 or 9 for TDD uplink/downlink configuration 0, and is 0 otherwise, and represents a total number of PHICH groups.

[0056] In another aspect, a high degree OCC can be applied to the DM-RS. The OCC with length N may be used for DM-RS generation, where N can be predefined by the system or indicated by the DCI or higher layer signaling. As there are only 2 symbols for DM-RS, to utilize an OCC-N (N > 2), a cross-subframe OCC may be used. Therefore an uplink TTI bundling or an aggregated subframe scheduling may be used.

[0057] In one aspect, the DMRS sequence ( generation can be defined

according to Equation 9,

wherein m and wherein T denotes the subcarrier, x denotes

the starting subcarrier, μ denotes a layer index, M^c indicates a number of subcarriers in the resource blocks, refers to an orthogonal complimentary code,

represent a Zadoff-Chu sequence, mdy indicates the index within one TTI bundling group, for example, for the second subframe in the TTI bundling, y can be 1.

[0058] In another aspect, both the comb based DMRS pattern and higher OCC based DM-RS pattern can be used. Then the DMRS sequence generation can be defined according to Equation 10,

[0059] FIG. 10 illustrates example components of a device in accordance with some embodiments. In some embodiments, the device 1000 may include application circuitry 1002, baseband circuitry 1004, Radio Frequency (RF) circuitry 1006, front-end module (FEM) circuitry 1008, and one or more antennas 1010, coupled together at least as shown. The components of the illustrated device 1000 may be included a UE or a RAN node. In some embodiments, the device 1000 may include less elements (e.g., a RAN node may not utilize application circuitry 1002, and instead include a

processor/controller to process IP data received from an EPC). In some embodiments, the device 1000 may include additional elements such as, for example, memory /storage, display, camera, sensor, and/or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C-RAN) implementations).

[0060] The application circuitry 1002 may include one or more application processors. For example, the application circuitry 1002 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. In some embodiments, processors of application circuitry 1002 may process IP data packets received from an EPC.

[0061] The baseband circuitry 1004 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 1004 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 1006 and to generate baseband signals for a transmit signal path of the RF circuitry 1006. Baseband processing circuity 1004 may interface with the application circuitry 1002 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 1006. For example, in some embodiments, the baseband circuitry 1004 may include a second generation (2G) baseband processor 1004a, third generation (3G) baseband processor 1004b, fourth generation (4G) baseband processor 1004c, and/or other baseband processor(s) 1004d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 1004 (e.g., one or more of baseband processors 1004a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 1006. In other embodiments, some or all of the functionality of baseband processors 1004a-d may be included in modules stored in the memory 1004g and executed via a Central Processing Unit (CPU) 1004e. The radio control

functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments,

modulation/demodulation circuitry of the baseband circuitry 1004 may include Fast- Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 1004 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.

[0062] In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 1004f. The audio DSP(s) 1004f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. 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 1004 and the application circuitry 1002 may be implemented together such as, for example, on a system on a chip (SOC).

[0063] In some embodiments, the baseband circuitry 1004 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 1004 may support communication with an

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 1004 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[0064] RF circuitry 1006 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 1006 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 1006 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 1008 and provide baseband signals to the baseband circuitry 1004. RF circuitry 1006 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 1004 and provide RF output signals to the FEM circuitry 1008 for transmission.

[0065] In some embodiments, the RF circuitry 1006 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 1006 may include mixer circuitry 1006a, amplifier circuitry 1006b and filter circuitry 1006c. The transmit signal path of the RF circuitry 1006 may include filter circuitry 1006c and mixer circuitry 1006a. RF circuitry 1006 may also include synthesizer circuitry 1006d for synthesizing a frequency for use by the mixer circuitry 1006a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 1006a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 1008 based on the synthesized frequency provided by synthesizer circuitry 1006d. The amplifier circuitry 1006b may be configured to amplify the down-converted signals and the filter circuitry 1006c 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 1004 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 1006a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0066] In some embodiments, the mixer circuitry 1006a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 1006d to generate RF output signals for the FEM circuitry 1008. The baseband signals may be provided by the baseband circuitry 1004 and may be filtered by filter circuitry 1006c. The filter circuitry 1006c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[0067] In some embodiments, the mixer circuitry 1006a of the receive signal path and the mixer circuitry 1006a 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 1006a of the receive signal path and the mixer circuitry 1006a 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 1006a of the receive signal path and the mixer circuitry 1006a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 1006a of the receive signal path and the mixer circuitry 1006a of the transmit signal path may be configured for superheterodyne operation.

[0068] 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 1006 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 1004 may include a digital baseband interface to communicate with the RF circuitry 1006.

[0069] 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.

[0070] In some embodiments, the synthesizer circuitry 1006d 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 1006d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[0071] The synthesizer circuitry 1006d may be configured to synthesize an output frequency for use by the mixer circuitry 1006a of the RF circuitry 1006 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 1006d may be a fractional N/N+l synthesizer.

[0072] 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 1004 or the applications processor 1002 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 1002.

[0073] Synthesizer circuitry 1006d of the RF circuitry 1006 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 (DPA). 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.

[0074] In some embodiments, synthesizer circuitry 1006d 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 1006 may include an IQ/polar converter.

[0075] FEM circuitry 1008 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 1010, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 1006 for further processing. FEM circuitry 1008 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 1006 for transmission by one or more of the one or more antennas 1010.

[0076] In some embodiments, the FEM circuitry 1008 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 1006). The transmit signal path of the FEM circuitry 1008 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 1006), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 1010.

[0077] In some embodiments, the device 1000 comprises a plurality of power saving mechanisms. If the device 1000 is in an RRC_Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device may power down for brief intervals of time and thus save power.

[0078] If there is no data traffic activity for an extended period of time, then the device 1000 may transition off to an RRC Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device 1000 goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device cannot receive data in this state, in order to receive data, it transitions back to

RRC Connected state.

[0079] An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable.

[0080] Processors of the application circuitry 1002 and processors of the baseband circuitry 1004 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry 1004, alone or in combination, may be used execute Layer 3, Layer 2, and/or Layer 1 functionality, while processors of the application circuitry 1004 may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., transmission

communication protocol (TCP) and user datagram protocol (UDP) layers). As referred to herein, Layer 3 may comprise a radio resource control (RRC) layer, described in further detail below. As referred to herein, Layer 2 may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 may comprise a physical (PHY) layer of a UE/RAN node, described in further detail below.

[0081] FIG. 11 illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry 1004 of FIG. 10 may comprise processors 1004A-1004E and a memory 1004G utilized by said processors. Each of the processors 1004A-1004E may include a memory interface, 1104A-1104E, respectively, to send/receive data to/from the memory 1004G.

[0082] The baseband circuitry 1004 may further include one or more interfaces to communicatively couple to other circuitries/devices, such as a memory interface 1112 (e.g., an interface to send/receive data to/from memory external to the baseband circuitry 1004), an application circuitry interface 1114 (e.g., an interface to send/receive data to/from the application circuitry 1002 of FIG. 10), an RF circuitry interface 1116 (e.g., an interface to send/receive data to/from RF circuitry 1006 of FIG. 10), and a wireless hardware connectivity interface 1118 (e.g., an interface to send/receive data to/from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components).

[0083] FIG. 12 is an illustration of a control plane protocol stack in accordance with some embodiments. In this embodiment, a control plane 1200 is shown as a communications protocol stack between the UE XT01 (or alternatively, the UE XT02), the RAN node XT11 (or alternatively, the RAN node XT12) and the MME XT21.

[0084] The PHY layer 1201 transmits and/or receives information used by the MAC layer 1202 over one or more air interfaces. The PHY layer 1201 may further perform link adaptation or adaptive modulation and coding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes) and other measurements used by higher layers, such as the RRC layer 1205, error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, modulation/demodulation of physical channels, interleaving, rate matching, mapping onto physical channels, and Multiple Input Multiple Output (MIMO) antenna processing.

[0085] The MAC layer 1202 performs mapping between logical channels and transport channels, multiplexing of MAC service data units (SDUs) from one or more logical channels onto transport blocks (TB) to be delivered to PHY via transport channels, de-multiplexing MAC SDUs to one or more logical channels from transport blocks (TB) delivered from the PHY via transport channels, multiplexing MAC SDUs onto TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), and logical channel prioritization.

[0086] The RLC layer 1203 may operate in a plurality of modes of operation, including: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC layer 1203 may execute transfer of upper layer protocol data units (PDUs), error correction through automatic repeat request (ARQ) for AM data transfers, and concatenation, segmentation and reassembly of RLC SDUs for UM and AM data transfers. The RLC layer 1203 may also execute re-segmentation of RLC data PDUs for AM data transfers, reorder RLC data PDUs for UM and AM data transfers, detect duplicate data for UM and AM data transfers, discard RLC SDUs for UM and AM data transfers, detect protocol errors for AM data transfers, and perform RLC re-establishment.

[0087] The PDCP layer 1204 may execute header compression and

decompression of IP data, maintain PDCP Sequence Numbers (SNs), perform in- sequence delivery of upper layer PDUs at re-establishment of lower layers, eliminate duplicates of lower layer SDUs at re-establishment of lower layers for radio bearers mapped on RLC AM, ciphering and deciphering of control plane data, integrity protection and integrity verification of control plane data, timer based discard of data, and security (e.g., ciphering, deciphering, integrity protection, integrity verification, etc.).

[0088] The main services and functions of the RRC layer 1205 may include broadcast of system information (e.g., included in Master Information Blocks (MIBs) or System Information Blocks (SIBs) related to the non-access stratum (NAS)), broadcast of system information related to the access stratum (AS), paging, establishment,

maintenance and release of an RRC connection between the UE and E-UTRAN (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance and release of point to point Radio Bearers, security functions including key management, inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting. Said MIBs and SIBs may comprise one or more information elements (IEs), which may each comprise individual data fields or data structures. [0089] The UE XTOl and the RAN node XTl 1 may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data via a protocol stack comprising the PHY layer 1201, the MAC layer 1202, the RLC layer 1203, the PDCP layer 1204, and the RRC layer 1205.

[0090] The non-access stratum (NAS) protocols 1206 form the highest stratum of the control plane between the UE XTOl and the MME XT21. The NAS protocols 1206 support the mobility of the UE XTOl and the session management procedures to establish and maintain IP connectivity between the UE XTOl and the P-GW XT23.

[0091] The SI Application Protocol (S l-AP) layer 1215 supports the functions of the SI interface and comprises Elementary Procedures (EPs). An EP is a unit of interaction between the RAN node XTl 1 and the EPC XT20. The S 1-AP layer services comprise two groups: UE-associated services and non UE-associated services. These services perform functions including, but are not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transport, RAN Information Management (RIM), and configuration transfer.

[0092] The Stream Control Transmission Protocol (SCTP) layer (alternatively referred to as the SCTP/IP layer) 1214 ensures reliable delivery of signaling messages between the RAN node XTl 1 and the MME XT21 based, in part, on the IP protocol, supported by the IP layer 1213. The L2 layer 1212 and the LI layer 1211 refers to communication links (e.g., wired or wireless) used by the RAN node and the MME to exchange information.

[0093] The RAN node XTl 1 and the MME XT21 may utilize an SI -MME interface to exchange control plane data via a protocol stack comprising the LI layer 1211, the L2 layer 1212, the IP layer 1213, the SCTP layer 1214, and the S l-AP layer 1215.

[0094] FIG. 13 is an illustration of a user plane protocol stack in accordance with some embodiments. In this embodiment, a user plane 1300 is shown as a communications protocol stack between the UE XTOl (or alternatively, the UE XT02), the RAN node XTl 1 (or alternatively, the RAN node XT12), the S-GW XT22, and the P- GW XT23. The user plane 1300 may utilize at least some of the same protocol layers as the control plane 1200. For example, the UE XTOl and the RAN node XTl 1 may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange user plane data via a protocol stack comprising the PHY layer 1201, the MAC layer 1202, the RLC layer 1203, the PDCP layer 1204.

[0095] The General Packet Radio Service (GPRS) Tunneling Protocol for the user plane (GTP-U) layer 1304 may be used for carrying user data within the GPRS core network and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats. The UDP and IP security (UDP/IP) layer 1303 may provide checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication on the selected data flows. The RAN node XT11 and the S-GW XT22 may utilize an Sl-U interface to exchange user plane data via a protocol stack comprising the LI layer 1211, the L2 layer 1212, the UDP/IP layer 1303, and the GTP-U layer 1304. The S-GW XT22 and the P-GW XT23 may utilize an S5/S8a interface to exchange user plane data via a protocol stack comprising the LI layer 1211, the L2 layer 1212, the UDP/IP layer 1303, and the GTP-U layer 1304. As discussed above with respect to FIG. 12, NAS protocols support the mobility of the UE XT01 and the session management procedures to establish and maintain IP connectivity between the UE XT01 and the P- GW XT23.

[0096] FIG. 14 illustrates components of a core network in accordance with some embodiments. The components of the EPC XT20 may be implemented in one physical node or separate physical nodes including components to read and execute instructions from a machine-readable or computer-readable medium (e.g., a non- transitory machine-readable storage medium). In some embodiments, Network Functions Virtualization (NFV) is utilized to virtualize any or all of the above described network node functions via executable instructions stored in one or more computer readable storage mediums (described in further detail below). A logical instantiation of the EPC network XT20 may be referred to as a network slice 1401. A logical instantiation of a portion of the EPC network XT20 may be referred to as a network sub-slice Y02 (e.g., the network sub-slice Y02 is shown to include the PGW XT23 and the PCRF XT26).

[0097] FIG. 15 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer- readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, FIG. 15 shows a diagrammatic representation of hardware resources 1500 including one or more processors (or processor cores) 1510, one or more memory /storage devices 1520, and one or more communication resources 1530, each of which are communicatively coupled via a bus 1540. For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor 1502 may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources 1500

[0098] The processors 1510 (e.g., a central processing unit (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 1512 and a processor 1514. The memory /storage devices 1520 may include main memory, disk storage, or any suitable combination thereof.

[0099] The communication resources 1530 may include interconnection and/or network interface components or other suitable devices to communicate with one or more peripheral devices 1504 and/or one or more databases 1506 via a network 1508. For example, the communication resources 1530 may include wired communication components (e.g., for coupling via a Universal Serial Bus (USB)), cellular

communication components, NFC components, Bluetooth® components (e.g.,

Bluetooth® Low Energy), Wi-Fi® components, and other communication components.

[00100] Instructions 1550 may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors 1510 to perform any one or more of the methodologies discussed herein. The instructions 1550 may reside, completely or partially, within at least one of the processors 1510 (e.g., within the processor's cache memory), the memory /storage devices 1520, or any suitable combination thereof. Furthermore, any portion of the instructions 1550 may be transferred to the hardware resources 1500 from any combination of the peripheral devices 1504 and/or the databases 1506. Accordingly, the memory of processors 1510, the memory /storage devices 1520, the peripheral devices 1504, and the databases 1506 are examples of computer-readable and machine-readable media. [00101] FIG. 16 illustrates a diagram of a UE 1600, in accordance with an example. The UE may be a mobile station (MS), a mobile wireless device, a mobile communication device, a tablet, a handset, or other type of wireless device. In one aspect, the UE 1600 can include at least one of an antenna 1605, a touch sensitive display screen 1610, a speaker 1615, a microphone 1620, a graphics processor 1625, a baseband processor 1630, an application processor 1635, intemal memory 1640, a keyboard 1645, a non-volatile memory port 1650, and combinations thereof.

[00102] The UE can include one or more antennas configured to communicate with a node or transmission station, such as a base station (BS), an evolved Node B (eNB), a baseband unit (BBU), a remote radio head (RRH), a remote radio equipment

(RRE), a relay station (RS), a radio equipment (RE), a remote radio unit (RRU), a central processing module (CPM), or other type of wireless wide area network (WWAN) access point. The wireless device can be configured to communicate using at least one wireless communication standard including 3GPP LTE, WiMAX, High Speed Packet Access (HSPA), Bluetooth, and WiFi. The wireless device can communicate using separate antennas for each wireless communication standard or shared antennas for multiple wireless communication standards. The wireless device can communicate in a wireless local area network (WLAN), a wireless personal area network (WPAN), and/or a WWAN. The mobile device can include a storage medium. In one aspect, the storage medium can be associated with and/or communicate with the application processor, the graphics processor, the display, the non-volatile memory port, and/or intemal memory. In one aspect, the application processor and graphics processor are storage mediums.

EXAMPLES

[00103] The following examples pertain to specific technology embodiments and point out specific features, elements, or steps that may be used or otherwise combined in achieving such embodiments.

[00104] Embodiment 1 includes an apparatus of a User Equipment (UE) operable to support channel estimation for communicating data comprising: one or more processors configured to: encode a demodulation reference signal (DM-RS) in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of RBs in one or more subframes for an uplink transmission to a Radio Access Network Node (RAN node), wherein the allocation to encode the DM-RS in the one or more RBs by the UE is aligned with allocations to encode DM-RSs on the one or more RBs by a plurality of other UEs; and encode data in the PUSCH based on an allocation of a subset of the RBs for the uplink transmission to the RAN node; and a memory interface configured to interface a memory device with the one or more processors to access the data for encoding in the PUSCH stored in the memory device.

[00105] Embodiment 2 includes the apparatus of embodiment 1 , wherein different orthogonal complimentary codes are used to encode the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

[00106] Embodiment 3 includes the apparatus of embodiment 1 , wherein different cyclic shifts are used to encode the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

[00107] Embodiment 4 includes the apparatus of embodiment 1 , wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS for intra-cell interference reduction.

[00108] Embodiment 5 includes the apparatus of embodiment 4, wherein combining the DM-RS of the UE with other DM-RS utilizing Frequency Division Multiplexing (FDM) includes a comb based DM-RS pattern. [00109] Embodiment 6 includes the apparatus of embodiment 4, wherein the encoded DM-RS is mapped to each of one or a plurality (T) of subcarriers within the resource blocks in a predetermined time slot.

[00110] Embodiment 7 includes the apparatus of embodiment 6, wherein a sequence of the DM-RS includes

wherein

and wherein T denotes the subcarrier, x denotes the starting subcarrier, μ denotes a layer index, indicates a number of subcarriers in

the resource blocks,

refers to an orthogonal complimentary code, and

represent a Zadoff-Chu sequence. [00111] Embodiment 8 includes the apparatus of embodiment 4, wherein a resource index for a physical hybrid-automatic repeat request indicator channel (PHICH) is based on a starting resource block index of the resource block, a cyclic shift (n_DMRS) and a starting subcarrier (x).

wherein, is a function of a transport block (TB) index and a first physical resource

block (PRB) index for PUSCH, is ^a function of a cyclic shift and an orthogonal

complimentary code (OCC) index defined in a downlink control information (DO), x denotes the starting subcarrier, is a spreading factor size used for modulation,

is 1 at subframe 4 or 9 for time division duplex (TDD) uplink/downlink

configuration 0, and is 0 otherwise, and represents a total number of PHICH

groups.

[00113] Embodiment 10 includes the apparatus of embodiment 1 , wherein the DM-RS of the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

[00114] Embodiment 11 includes the apparatus of embodiment 10, wherein a sequence of the DM-RS is defined as

wherein and wherein T denotes the subcarrier, x denotes

the resource blocks, refers to an orthogonal complimentary code,

represent a Zadoff-Chu sequence, and y indicates the index within one TTI bundling group. [00115] Embodiment 12 includes the apparatus of embodiment 1 , wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) and a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

[00116] Embodiment 13 includes the apparatus of embodiment 12, wherein a sequence of the DM-RS is defined as

wherein

, and wherein T denotes the subcarrier, x denotes the starting subcarrier, μ denotes a layer index,

indicates a number of subcarriers in the resource blocks, refers to an orthogonal complimentary code,

represent a Zadoff-Chu sequence, and j indicates the index within one TTI bundling group.

[00117] Embodiment 14 includes the apparatus of embodiments 1, 4, 10 or 12, wherein the one or more processors are further configured to: decode one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in the one or more resource blocks and the allocation to encode the data in the subset of the resource blocks; and configure the encoding of resource blocks by UE based on the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks.

[00118] Embodiment 15 includes the apparatus of embodiment 14, wherein the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks is included in an additional resource allocation field of a radio resource control (RRC) signaling received from the RAN node.

[00119] Embodiment 16 includes the apparatus of embodiment 14, wherein a starting subcarrier (x) of the DM-RS in the resource block can be configured by downlink control information (DCI) or higher layer signaling.

[00120] Embodiment 17 includes an apparatus of a User Equipment (UE) operable to support channel estimation for communicating data comprising: one or more processors configured to: encode a demodulation reference signal (DM-RS) in each of a plurality of subsets of subcarriers in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of resource blocks for an uplink transmission to Radio Access Network Node (RAN node); and encode data in the PUSCH based on the allocation of the resource blocks for the uplink transmission to the RAN node; and a memory interface configured to interface a memory device with the one or more processors to access the data for encoding in the PUSCH stored in the memory device.

[00121] Embodiment 18 includes the apparatus of embodiment 17, wherein encoding the DM-RS in each of the plurality of subset of subcarriers in one or more RBs is based on a frequency shift, a decimation factor, cyclic shift and an Orthogonal Complimentary Code (OCC).

[00122] Embodiment 19 includes the apparatus of embodiment 18, wherein the decimator factor includes 2 or 4 and indicates that the DM-RS is transmitted in each of the plurality of subsets of subcarriers within the allocation of the resource blocks.

[00123] Embodiment 20 includes the apparatus of embodiment 18, wherein the cyclic frequency shift comprises a range of 0, 1, ... , X-l and includes the set of the decimated subcarriers for encoding the DM-RS.

[00124] Embodiment 21 includes the apparatus of embodiment 18, wherein a comb is based on

wherein the is indicated in the DCI, c(2n_s) is a pseudo-random

[00125] Embodiment 22 includes the apparatus of embodiment 18, wherein a comb is based on,

where the d_DCI = (0, ... , RFP— 1} is indicated in the DCI, c(n_s) is a pseudo-random sequence, which can be initialized using RRC signaling every N-th subframe, wherein N can be 20 or 40, n_s can be the slot index and RFP can be the maximum number of communication channels supported by DM-RS.

[00126] Embodiment 23 includes the apparatus of embodiment 18, wherein a subcarrier mapping is signaled by RRC and the subcarrier shift, 0, ... , X-l , is dynamically signaled in a DCI.

[00127] Embodiment 24 includes the apparatus of embodiment 17, wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS for intra-cell interference reduction.

[00128] Embodiment 25 includes the apparatus of embodiment 24, wherein combining the DM-RS of the UE with other DM-RS utilizing Frequency Division Multiplexing (FDM) includes a comb based DM-RS pattern.

[00129] Embodiment 26 includes the apparatus of embodiment 24, wherein the encoded DM-RS is mapped to each of one or a plurality (T) of subcarriers within the resource blocks in a predetermined time slot.

[00130] Embodiment 27 includes the apparatus of embodiment 26, wherein a sequence of the DM-Rs includes:

wherein , and wherein T denotes the subcarrier, x denotes

the resource blocks, refers to an orthogonal complimentary code, and

represent a Zadoff-Chu sequence.

[00131] Embodiment 28 includes the apparatus of embodiment 24, wherein a resource index for a physical hybrid-automatic repeat request indicator channel (PHICH) is based on a starting resource block index of the resource block, a cyclic shift

and a starting subcarrier (x).

[00132] Embodiment 29 includes the apparatus of embodiment 28, wherein the resource index of the PHICH includes,

block (PRB) index for PUSCH, is a function of a cyclic shift and an orthogonal

IpHicH is 1 at subframe 4 or 9 for time division duplex (TDD) uplink/downlink configuration 0, and is 0 otherwise, and represents a total number of PHICH

groups.

[00133] Embodiment 30 includes the apparatus of embodiment 17, wherein the DM-RS of the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

[00134] Embodiment 31 includes the apparatus of embodiment 30, wherein a sequence of the DM-RS is defined as,

wherein and wherein T denotes the subcarrier, x denotes

the resource blocks, refers to an orthogonal complimentary code

represent a Zadoff-Chu sequence, andj indicates the index within one TTI bundling group.

[00135] Embodiment 32 includes the apparatus of embodiment 19, wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) and a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

[00136] Embodiment 33 includes the apparatus of embodiment 32, wherein a sequence of the DM-RS is defined as,

wherein — 1, and wherein T denotes the subcarrier, x denotes

the starting subcarrier, μ denotes a layer index,

[00137] Embodiment 34 includes the apparatus of embodiments 17, 24, 30 or 32, wherein the one or more processors are further configured to: decode one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB); and configure the encoding of resource block based on the one or more parameters including the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB) and the allocation to encode the data in the allocation of the resource blocks.

[00138] Embodiment 35 includes the apparatus of embodiment 34, wherein the one or more parameters indicating the resource allocation for DM-RS include a cyclic frequency shift, a decimator factor and an orthogonal complimentary code.

[00139] Embodiment 36 includes at least one machine readable storage medium having instructions embodied thereon for channel estimation in a wireless communication system, the instructions when executed perform the following: encoding, by a User Equipment (UE), a demodulation reference signal (DM-RS) in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of RBs in one or more subframes for an uplink transmission to a Radio Access Network Node (RAN node), wherein the allocation to encode the DM-RS in the one or more RBs is aligned with allocations to encode DM-RS s on the one or more RBs by a plurality of other UEs; and encoding, by the UE, data in the PUSCH based on an allocation of a subset of the RBs for the uplink transmission to the RAN node.

[00140] Embodiment 37 includes the apparatus of embodiment 36, wherein different orthogonal complimentary codes are used for encoding the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

[00141] Embodiment 38 includes the apparatus of embodiment 36, wherein different cyclic shifts are used for encoding the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

[00142] Embodiment 39 includes the apparatus of embodiment 36, wherein the DM-RS encoded by the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS.

[00143] Embodiment 40 includes the apparatus of embodiment 36, wherein the

DM-RS encoded by the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS.

[00144] Embodiment 41 includes the apparatus of embodiment 36, further comprising: decoding, by the UE, one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in the one or more resource blocks and the allocation to encode the data in the subset of the resource blocks; and configuring, by the UE, the encoding of resource blocks based on the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks.

[00145] Embodiment 42 includes at least one machine readable storage medium having instructions embodied thereon for channel estimation in a wireless communication system, the instructions when executed perform the following: encoding, by a User Equipment (UE), a demodulation reference signal (DM-RS) in each of a plurality of subsets of subcarriers in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of resource blocks for an uplink transmission to Radio Access Network Node (RAN node); and encoding, by the UE, data in the PUSCH based on the allocation of the resource blocks for the uplink transmission to the RAN node.

[00146] Embodiment 43 includes the apparatus of embodiment 42, wherein the DM-RS encoded by the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS. [00147] Embodiment 44 includes the apparatus of embodiment claim 42, wherein the DM-RS encoded by the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS.

[00148] Embodiment 45 includes the apparatus of embodiment 42, further comprising: decoding, by the UE, one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB); and configuring, by the UE, the encoding of resource block based on the one or more parameters including the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB) and the allocation to encode the data in the allocation of the resource blocks.

[00149] Embodiment 46 includes an apparatus of a User Equipment (UE) operable to support channel estimation for communicating data comprising: a means for encoding, by a User Equipment (UE), a demodulation reference signal (DM-RS) in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of RBs in one or more subframes for an uplink transmission to a Radio Access Network Node (RAN node), wherein the allocation to encode the DM-RS in the one or more RBs is aligned with allocations to encode DM-RSs on the one or more RBs by a plurality of other UEs; and a means for encoding, by the UE, data in the PUSCH based on an allocation of a subset of the RBs for the uplink transmission to the RAN node.

[00150] Embodiment 47 includes the apparatus of embodiment 46, wherein different orthogonal complimentary codes are used for encoding the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

[00151] Embodiment 48 includes the apparatus of embodiment 46, wherein different cyclic shifts are used for encoding the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

[00152] Embodiment 49 includes the apparatus of embodiment 46, wherein the DM-RS encoded by the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS. [00153] Embodiment 50 includes the apparatus of embodiment 46, wherein the DM-RS encoded by the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS.

[00154] Embodiment 51 includes the apparatus of embodiment 46, further comprising: a means for decoding, by the UE, one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in the one or more resource blocks and the allocation to encode the data in the subset of the resource blocks; and means for configuring, by the UE, the encoding of resource blocks based on the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks.

[00155] Embodiment 52 includes an apparatus of a User Equipment (UE) operable to support channel estimation for communicating data comprising: a means for encoding, by a User Equipment (UE), a demodulation reference signal (DM-RS) in each of a plurality of subsets of subcarriers in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of resource blocks for an uplink transmission to Radio Access Network Node (RAN node); and a means for encoding, by the UE, data in the PUSCH based on the allocation of the resource blocks for the uplink transmission to the RAN node.

[00156] Embodiment 53 includes the apparatus of embodiment 52, wherein the

DM-RS encoded by the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS.

[00157] Embodiment 54 includes the apparatus of embodiment claim 52, wherein the DM-RS encoded by the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS.

[00158] Embodiment 55 includes the apparatus of embodiment 52, further comprising: a means for decoding, by the UE, one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB); and a means for configuring, by the UE, the encoding of resource block based on the one or more parameters including the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB) and the allocation to encode the data in the allocation of the resource blocks.

[00159] 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), 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 aspects, 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 aspects, circuitry may include logic, at least partially operable in hardware.

[00160] Various techniques, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, compact disc-read-only memory (CD-ROMs), hard drives, transitory or non- transitory computer readable storage medium, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the various techniques. Circuitry may include hardware, firmware, program code, executable code, computer instructions, and/or software. A non-transitory computer readable storage medium may be a computer readable storage medium that does not include signal. In the case of program code execution on programmable computers, the computing device may include a processor, a storage medium readable by the processor (including volatile and nonvolatile memory and/or storage elements), at least one input device, and at least one output device. The volatile and non-volatile memory and/or storage elements may be a random-access memory (RAM), erasable programmable read only memory (EPROM), flash drive, optical drive, magnetic hard drive, solid state drive, or other medium for storing electronic data. The node and wireless device may also include a transceiver module (i.e., transceiver), a counter module (i.e., counter), a processing module (i.e., processor), and/or a clock module (i.e., clock) or timer module (i.e., timer). One or more programs that may implement or utilize the various techniques described herein may use an application programming interface (API), reusable controls, and the like. Such programs may be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) may be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations.

[00161] As used herein, the term processor may include general purpose processors, specialized processors such as VLSI, FPGAs, or other types of specialized processors, as well as base band processors used in transceivers to send, receive, and process wireless communications.

[00162] It should be understood that many of the functional units described in this specification have been labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[00163] Modules may also be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module cannot be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.

[00164] Indeed, a module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network. The modules may be passive or active, including agents operable to perform desired functions. [00165] Reference throughout this specification to "an example" or "exemplary" means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present technology. Thus, appearances of the phrases "in an example" or the word "exemplary" in various places throughout this specification are not necessarily all referring to the same embodiment.

[00166] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present technology may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and altematives are not to be construed as defacto equivalents of one another, but are to be considered as separate and autonomous representations of the present technology.

[00167] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of layouts, distances, network examples, etc., to provide a thorough understanding of embodiments of the technology. One skilled in the relevant art will recognize, however, that the technology may be practiced without one or more of the specific details, or with other methods, components, layouts, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the technology.

[00168] While the forgoing examples are illustrative of the principles of the present technology in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation may be made without the exercise of inventive faculty, and without departing from the principles and concepts of the technology. Accordingly, it is not intended that the technology be limited, except as by the claims set forth below.

Claims

CLAIMS What is claimed is:

1. An apparatus of a User Equipment (UE) operable to support channel estimation for communicating data comprising:

one or more processors configured to:

encode a demodulation reference signal (DM-RS) in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of RBs in one or more subframes for an uplink transmission to a Radio Access Network Node (RAN node), wherein the allocation to encode the DM-RS in the one or more RBs by the UE is aligned with allocations to encode DM-RSs on the one or more RBs by a plurality of other UEs; and

encode data in the PUSCH based on an allocation of a subset of the RBs for the uplink transmission to the RAN node; and

a memory interface configured to interface a memory device with the one or more processors to access the data for encoding in the PUSCH stored in the memory device.

2. The apparatus of claim 1, wherein different orthogonal complimentary codes are used to encode the DM-RS in the one or more resource blocks by the UE and the DM- RSs in the one or more resource blocks by the plurality of other UEs.

3. The apparatus of claim 1, wherein different cyclic shifts are used to encode the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

4. The apparatus according to claim 1, wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS for intra- cell interference reduction.

5. The apparatus according to claim 4, wherein combining the DM-RS of the UE with other DM-RS utilizing Frequency Division Multiplexing (FDM) includes a comb based DM-RS pattern.

6. The apparatus according to claim 4, wherein the encoded DM-RS is mapped to each of one or a plurality (T) of subcarriers within the resource blocks in a predetermined time slot.

7. The apparatus according to claim 6, wherein a sequence of the DM-RS

the resource blocks,

refers to an orthogonal complimentary code, and

represent a Zadoff-Chu sequence.

8. The apparatus according to claim 4, wherein a resource index for a physical hybrid-automatic repeat request indicator channel (PHICH) is based on a starting resource block index of the resource block, a cyclic shift and a starting subcarrier (x).

9. The apparatus according to claim 8, wherein the resource index of the PHICH includes,

block (PRB) index for PUSCH, n_DMRS is a function of a cyclic shift and an orthogonal complimentary code (OCC) index defined in a downlink control information (DCI), x denotes the starting subcarrier, is a spreading factor size used for modulation,

groups.

10. The apparatus according to claim 1, wherein the DM-RS of the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third higher order with other DM-RS for intra-cell interference reduction.

1 1. The apparatus according to claim 10, wherein a sequence of the DM-RS is defined as

wherein m and wherein T denotes the subcarrier, x denotes

the resource blocks, w ^μ (m) refers to an orthogonal complimentary code,

represent a Zadoff-Chu sequence, and y indicates the index within one TTI bundling group.

12. The apparatus of claim 1 , wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) and a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

13. The apparatus of claim 12, wherein a sequence of the DM-RS is defined as

wherein and wherein T denotes the subcarrier, x denotes

the resource blocks, refers to an orthogonal complimentary code,

14. The apparatus of claims 1, 4, 10 or 12, wherein the one or more processors are further configured to:

decode one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in the one or more resource blocks and the allocation to encode the data in the subset of the resource blocks; and configure the encoding of resource blocks by UE based on the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks.

15. The apparatus of claim 14, wherein the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks is included in an additional resource allocation field of a radio resource control (RRC) signaling received from the RAN node.

16. The apparatus according to claims 14, wherein a starting subcarrier (x) of the DM-RS in the resource block can be configured by downlink control information (DCI) or higher layer signaling.

17. An apparatus of a User Equipment (UE) operable to support channel estimation for communicating data comprising:

one or more processors configured to:

encode a demodulation reference signal (DM-RS) in each of a plurality of subsets of subcarriers in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of resource blocks for an uplink transmission to Radio Access Network Node (RAN node); and

encode data in the PUSCH based on the allocation of the resource blocks for the uplink transmission to the RAN node; and a memory interface configured to interface a memory device with the one or more processors to access the data for encoding in the PUSCH stored in the memory device.

18. The apparatus of claim 17, wherein encoding the DM-RS in each of the plurality of subset of subcarriers in one or more RBs is based on a frequency shift, a decimation factor, cyclic shift and an Orthogonal Complimentary Code (OCC).

19. The apparatus of clam 18, wherein the decimator factor includes 2 or 4 and indicates that the DM-RS is transmitted in each of the plurality of subsets of subcarriers within the allocation of the resource blocks.

20. The apparatus of claim 18, wherein the cyclic frequency shift comprises a range of 0, 1 , ... , X-l and includes the set of the decimated subcarriers for encoding the DM-RS.

21. The apparatus of claim 18, wherein a comb is based on

wherein is indicated in the DCI, c(2n_s) is a pseudo-random

22. The apparatus of claim 18, wherein a comb is based on,

where the } is indicated in the DCI, ) is a pseudo-random

23. The apparatus of claim 18, wherein a subcarrier mapping is signaled by RRC and the subcarrier shift, 0, ... , X-l, is dynamically signaled in a DCI.

24. The apparatus according to claim 17, wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS for intra- cell interference reduction.

25. The apparatus according to claim 24, wherein combining the DM-RS of the UE with other DM-RS utilizing Frequency Division Multiplexing (FDM) includes a comb based DM-RS pattern.

26. The apparatus according to claim 24, wherein the encoded DM-RS is mapped to each of one or a plurality (T) of subcarriers within the resource blocks in a

predetermined time slot.

27. The apparatus according to claim 26, wherein a sequence of the DM-Rs includes:

wherein and wherein T denotes the subcarrier, x denotes

the resource blocks,

refers to an orthogonal complimentary code, and

represent a Zadoff-Chu sequence.

28. The apparatus according to claim 24, wherein a resource index for a physical hybrid-automatic repeat request indicator channel (PHICH) is based on a starting resource block index of the resource block, a cyclic shift (n_DMRS) and a starting subcarrier (x).

29. The apparatus according to claim 28, wherein the resource index of the PHICH includes,

block (PRB) index for PUSCH, is ^a function of a cyclic shift and an orthogonal

complimentary code (OCC) index defined in a downlink control information (DO), x denotes the starting subcarrier,

is a spreading factor size used for modulation, is 1 at subframe 4 or 9 for time division duplex (TDD) uplink/downlink

configuration 0, and is 0 otherwise, and represents a total number of PHICH

groups.

30. The apparatus according to claim 17, wherein the DM-RS of the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third higher order with other DM-RS for intra-cell interference reduction.

31. The apparatus according to claim 30, wherein a sequence of the DM-RS is defined as,

and wherein T denotes the subcarrier, x denotes

the resource blocks, refers to an orthogonal complimentary code,

represent a Zadoff-Chu sequence, andy indicates the index within one TTI bundling group.

32. The apparatus of claim 19, wherein the DM-RS of the UE is combined utilizing Frequency Division Multiplexing (FDM) and a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS for intra-cell interference reduction.

33. The apparatus of claim 32, wherein a sequence of the DM-RS is defined as,

wherein and wherein T denotes the subcarrier, x denotes

34. The apparatus of claims 17, 24, 30 or 32, wherein the one or more processors are further configured to:

decode one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB); and

configure the encoding of resource block based on the one or more parameters including the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB) and the allocation to encode the data in the allocation of the resource blocks.

35. The apparatus of claim 34, wherein the one or more parameters indicating the resource allocation for DM-RS include a cyclic frequency shift, a decimator factor and an orthogonal complimentary code.

36. At least one machine readable storage medium having instructions embodied thereon for channel estimation in a wireless communication system, the instructions when executed perform the following:

encoding, by a User Equipment (UE), a demodulation reference signal (DM-RS) in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of RBs in one or more subframes for an uplink transmission to a Radio Access Network Node (RAN node), wherein the allocation to encode the DM-RS in the one or more RBs is aligned with allocations to encode DM-RSs on the one or more RBs by a plurality of other UEs; and

encoding, by the UE, data in the PUSCH based on an allocation of a subset of the RBs for the uplink transmission to the RAN node.

37. The at least one machine readable storage medium of claim 36, wherein different orthogonal complimentary codes are used for encoding the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

38. The at least one machine readable storage medium of claim 36, wherein different cyclic shifts are used for encoding the DM-RS in the one or more resource blocks by the UE and the DM-RSs in the one or more resource blocks by the plurality of other UEs.

39. The at least one machine readable storage medium of claim 36, wherein the DM-RS encoded by the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS.

40. The at least one machine readable storage medium of claim 36, wherein the DM-RS encoded by the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS.

41. The at least one machine readable storage medium of claim 36, further comprising:

decoding, by the UE, one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in the one or more resource blocks and the allocation to encode the data in the subset of the resource blocks; and

configuring, by the UE, the encoding of resource blocks based on the one or more parameters including the allocation to encode the DM-RS in the one or more resource block and the allocation to encode the data in the subset of the resource blocks.

42. At least one machine readable storage medium having instructions embodied thereon for channel estimation in a wireless communication system, the instructions when executed perform the following:

encoding, by a User Equipment (UE), a demodulation reference signal (DM-RS) in each of a plurality of subsets of subcarriers in one or more resource blocks (RB) in a physical uplink shared channel (PUSCH) based on an allocation of resource blocks for an uplink transmission to Radio Access Network Node (RAN node); and

encoding, by the UE, data in the PUSCH based on the allocation of the resource blocks for the uplink transmission to the RAN node.

43. The at least one machine readable storage medium of claim 42, wherein the DM-RS encoded by the UE is combined utilizing Frequency Division Multiplexing (FDM) with other DM-RS.

44. The at least one machine readable storage medium of claim 42, wherein the DM-RS encoded by the UE is combined utilizing a cross-subframe orthogonal complimentary code (OCC) of a third or higher order with other DM-RS.

45. The at least one machine readable storage medium of claim 42, further comprising: decoding, by the UE, one or more parameters from the RAN node, wherein the one or more parameters include the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB); and

configuring, by the UE, the encoding of resource block based on the one or more parameters including the allocation to encode the DM-RS in each of the plurality of subsets of subcarriers in one or more resource blocks (RB) and the allocation to encode the data in the allocation of the resource blocks.