Patent Description:
The present disclosure, for example, relates to wireless communication systems, and more particularly to joint channel and phase noise estimation.

Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems. <CIT>, relates to a hybrid multicarrier technique to facilitate communications within a network.

By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).

Phase noise (PN) is commonly present in wireless transmissions. PN can lead to errors in channel estimation, degrade signal quality, and increase intercarrier interference among subcarriers, among other problems. Some radios, such as millimeter wave (mmW) radios, have higher phase noise levels than other radios, such as those using frequencies below <NUM> gigahertz (GHZ). This may be due to a higher frequency ratio between a local oscillator and a temperature compensated crystal oscillator of the radio. Such radios may also have noisier voltage control oscillators. In a downlink or uplink transmission, a user equipment (UE) may contribute a majority of the PN.

Performing channel estimation may be necessary for coherent detection of wireless transmissions. However, the channel estimate and the PN may be unknown during the reception of a control symbol. The channel estimate and the estimated PN may be used to demodulate control and data symbols.

In accordance with the present invention, there are provided a method for wireless communication as recited by claim <NUM>, and an apparatus for wireless communication as recited by claim <NUM>; preferred features are set out in the dependent claims. Techniques, apparatus, and systems described herein may be used to estimate a channel and phase noise (PN) in control symbols. A wireless device may generate control symbols that include both control tones and pilot tones. The control tones and the pilot tones may be arranged in the control symbols in one of several ways. Example ways of arranging the control tones and the pilot tones includes arranging each according to one or more sequences, alternating the control tones and the pilot tones, offsetting the pilot tones from the control tones, and combinations thereof. A receiving wireless device may use the pilot tones to determine a joint estimation of channel and PN.

The method, apparatuses, and non-transitory computer-readable medium may include additional features. Some examples include determine control information from the control tone, wherein determining control information is based at least in part on channel and phase noise estimation. Performing the phase noise estimation and the channel estimation may further include compensating the control symbol based on the phase noise estimation and performing the channel estimation based on the compensated phase noise.

Each of the figures is provided for the purpose of illustration and description only, and not as a definition of the limits of the claims.

Channel and phase noise (PN) may be estimated from control symbols that include pilot tones as well as control tones. A wireless device, such as a base station, may generate a control symbol that includes both control tones and pilot tones. The control tones and the pilot tones may be arranged in the control symbols according to a first and second periodicity, respectively. In some examples, the first and second periodicities may be the same with an offset between the control tones and the pilot tones. A receiving wireless device, such as a user equipment (UE), may use the pilot tones to determine a joint estimation of channel and PN.

<FIG> illustrates an example of a wireless communications system <NUM> in accordance with various aspects of the disclosure. The wireless communications system <NUM> includes base stations <NUM>, user equipment (UEs) <NUM>, and a core network <NUM>. The base stations <NUM> interface with the core network <NUM> through backhaul links <NUM> (e.g., S1, etc.) and may perform radio configuration and scheduling for communication with the UEs <NUM>, or may operate under the control of a base station controller. In various examples, the base stations <NUM> may communicate, either directly or indirectly (e.g., through core network <NUM>), with each other over backhaul links <NUM> (e.g., X1, etc.), which may be wired or wireless communication links. In some examples, the wireless communications system <NUM> may have protocols similar to that of a Long Term Evolution (LTE)/LTE-advanced (LTE-a) wireless network or a millimeter-wave based wireless network. In some examples, the wireless communications system <NUM> may be a millimeter-wave based wireless network.

The base stations <NUM> may wirelessly communicate with the UEs <NUM> via one or more base station antennas. Each of the base station <NUM> sites may provide communication coverage for a respective geographic coverage area <NUM>. In some examples, base stations <NUM> may be referred to as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area <NUM> for a base station <NUM> may be divided into sectors making up only a portion of the coverage area. The wireless communications system <NUM> may include base stations <NUM> of different types (e.g., macro and/or small cell base stations). There may be overlapping geographic coverage areas <NUM> for different technologies.

In some examples, the wireless communications system <NUM> is an LTE/LTE-A network. In LTE/LTE-A networks, the term evolved Node B (eNB) may be generally used to describe the base stations <NUM>, while the term UE may be generally used to describe the UEs <NUM>. The wireless communications system <NUM> may be a Heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographical regions. For example, each eNB or base station <NUM> may provide communication coverage for a macro cell, a small cell, and/or other types of cell. The term "cell" is a 3GPP term that can be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context.

Small cells may include pico cells, femto cells, and micro cells according to various examples A pico cell may cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell also may cover a relatively small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB or a home eNB.

The wireless communications system <NUM> may support synchronous or asynchronous operation.

The communication networks that may accommodate some of the various disclosed examples may be packet-based networks that operate according to a layered protocol stack. The MAC layer may also use Hybrid ARQ (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE <NUM> and the base stations <NUM> or core network <NUM> supporting radio bearers for the user plane data. At the Physical (PHY) layer, the transport channels may be mapped to Physical channels.

The UEs <NUM> are dispersed throughout the wireless communications system <NUM>, and each UE <NUM> may be stationary or mobile. A UE <NUM> may also include or be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. A UE may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, and the like.

The communication links <NUM> shown in wireless communications system <NUM> may include uplink (UL) transmissions from a UE <NUM> to a base station <NUM>, and/or downlink (DL) transmissions, from a base station <NUM> to a UE <NUM>. The downlink transmissions may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each communication link <NUM> may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies) modulated according to the various radio technologies described above. Each modulated signal may be sent on a different sub-carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links <NUM> may transmit bidirectional communications using FDD (e.g., using paired spectrum resources) or TDD operation (e.g., using unpaired spectrum resources). Frame structures for FDD (e.g., frame structure type <NUM>) and TDD (e.g., frame structure type <NUM>) may be defined.

In some embodiments of the wireless communications system <NUM>, base stations <NUM> and/or UEs <NUM> may include multiple antennas for employing antenna diversity schemes to improve communication quality and reliability between base stations <NUM> and UEs <NUM>. Additionally or alternatively, base stations <NUM> and/or UEs <NUM> may employ multiple-input, multiple-output (MIMO) techniques that may take advantage of multi-path environments to transmit multiple spatial layers carrying the same or different coded data.

Wireless communications system <NUM> may support operation on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), a layer, a channel, etc. A UE <NUM> may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation.

A base station, such as BS <NUM>-a, may include a BS control symbol component <NUM>. The BS control symbol component <NUM> may generate one or more control symbols for transmission according to techniques described herein. The BS control symbol component <NUM> may also estimate channel and phase noise from a received control symbol that includes pilot tones as well as control tones. Similarly, a wireless device, such as UE <NUM>-a, may include a UE control symbol component <NUM>. The UE control symbol component <NUM> may function similarly to the BS control symbol component <NUM>. However, for illustrative purposes, the examples included herein mainly describe a BS <NUM> generating the control symbols and the UE <NUM> estimating the channel and PN from the control symbols. However, it is to be understood that either the BS <NUM> or the UE <NUM> may generate or interpret control symbols.

Therefore, techniques described herein design a symbol that conveys control information which allows a receiver to estimate the channel profile in the presence of phase noise and additive channel noise. The symbol may be used for an airlink that uses a cyclic prefix (e.g., OFDM, single-carrier FDMA (SC-FDM), single-carrier cyclic prefix (SCCP), etc.).

<FIG> shows a flow diagram illustrating example channel and PN estimation in a wireless communications system <NUM>, in accordance with various aspects of the present disclosure. The wireless communications system <NUM> may include a UE <NUM>-b and BS <NUM>-b, which may be examples of a UE <NUM> and base station <NUM> described with reference to <FIG>.

Before the UE <NUM>-b performs channel and PN estimation, the BS <NUM>-b may send directional primary synchronization signals in different directions. The UEs within a cell of the BS <NUM>-b, for example the UE <NUM>-b, may feedback a best direction to the BS <NUM>-b. The BS <NUM>-b may then schedule a set of UEs that will receive downlink traffic.

In order for the UE <NUM>-b to jointly estimate channel and PN, the BS <NUM>-b may generate a control symbol (<NUM>). The BS <NUM>-b may include pilot tones and control tones in the control symbol. The BS <NUM>-b may also generate multiple control symbols.

The BS <NUM>-b may transmit the control symbol <NUM> to the UE <NUM>-b. Upon receiving the control symbol <NUM>, the UE <NUM>-b may estimate the channel and PN from the control symbol <NUM> (<NUM>). The BS <NUM>-b may transmit data <NUM> to the UE <NUM>-b. The BS <NUM>-b may use OFDMA or SC-FDMA, for example. The UE <NUM>-b may use the estimated channel and PN for coherent detection of the data <NUM>.

<FIG> illustrates an example sub-frame <NUM> structure that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. The sub-frame <NUM> may include a control symbol <NUM>-a, which may be examples of the control symbol <NUM> described with reference to <FIG>. The sub-frame <NUM> may also include one or more data symbols, such as data symbols <NUM>-a, <NUM>-b, and <NUM>-c which may be examples of the data symbol <NUM> described with reference to <FIG>.

In some examples, the sub-frame <NUM> may have <NUM> symbols and a <NUM> microsecond (µs) duration. The sub-frame <NUM> illustrates only a single UE allocation per sub-frame, but in other examples, two or more UEs may be multiplexed in a time domain.

The first symbol may be the control symbol <NUM>-a which transmits control information (e.g., scheduling, modulation and coding scheme (MCS) information, etc.). The control symbol <NUM>-a may include control tones that contain the control information. The control information may be pre-coded (e.g., with a discrete Fourier transform) and corresponding control tones may be inserted in the control symbol with a periodicity. In one example, the periodicity is every <NUM>th tone in the frequency domain. The control symbol may also include pilot tones for joint channel and PN estimation. The pilot tones may be encoded into the control symbol with a second periodicity, which may be the same or different than the periodicity of the control tones. In some examples, the periodicity of the pilot tones may be an integer multiple of the periodicity of the control tones. In examples where the chosen periodicities cause the pilot tones and the control tones to collide, the control tone sequence may be punctured (e.g., colliding control tones may not be used). The control tones and the pilot tones may be offset from each other.

As phase noise may vary quickly in time, PN mitigation pilot tones may be included in every symbol. Also, two or more channel estimation symbols may be included among the <NUM> symbols of the sub-frame <NUM>. Thus, the data <NUM>-a may include pilot tones for PN estimation. The data <NUM>-b may include a control symbol that has pilot tones and control tones for joint channel and PN estimation. The data <NUM>-c may include pilot tones for PN estimation.

<FIG> illustrates an example control symbol <NUM> structure in accordance with various aspects of the present disclosure. The illustration of the control symbol <NUM> represents tones in a frequency domain. The control symbol <NUM> may be an example of the control symbol <NUM> described with reference to <FIG> and <FIG>.

The control symbol <NUM> includes control tones <NUM>. The control tones <NUM> contain control information. To enable the control symbol <NUM> to be used for joint channel and PN estimation, the control symbol <NUM> also includes pilot tones <NUM>. The control symbol <NUM> may have null tones (i.e., no tone or information) between the control tones <NUM> and the pilot tones <NUM>. A receiver of the control symbol <NUM> may use the pilot tones <NUM> to jointly estimate channel and PN. Any occupied subcarrier in the control symbol <NUM> contains either a control tone or a pilot tone.

In the example of <FIG>, the control tones <NUM> are located at every eighth tone in the frequency domain. Thus the periodicity of inserting the control tones <NUM> may be one in every eight tones. The pilot tones <NUM> may also be located in the control symbol <NUM> with a periodicity, which in this example is also one in every eighth tone. The pilot tones <NUM> may be separated by the control tones <NUM> by an offset <NUM>. In this example, the offset <NUM> is four tones. The offset <NUM> may depend on a phase noise level, a channel delay spread, or combinations thereof. The example of <FIG> may handle a <NUM> nanosecond delay spread.

In other examples, other periodicities may be used for the pilot tones <NUM> and/or control tones <NUM>. Over one period length (e.g., eight tones in the example of <FIG>), the channel may not vary much. However, if the channel varies faster, the period length of the pilot tones <NUM> may be shortened. On the other hand, the PN may spill spectral power from the pilot tones and control tones to their respective neighboring tones. To keep this mutual interference small, in some examples the offset <NUM> may not be shortened below a selected limit. Some periodicities may be one in every seven or nine tones, for example, while other periodicities may be used in other examples. In some examples, the periodicity may be dependent on a power spectrum of the phase noise.

The phase of the pilot tones <NUM> may be modulated according to a known sequence. The sequence may be a Zadoff-Chu sequence, a gold sequence, or any other suitable sequence. This sequence may be a reference sequence of pilot tones. With r(m) denoting the transmitted sequence with m denoting the index, r(m) may map to a complex valued modulation symbol ak, used as a pilot tone, according to Equation <NUM>. <MAT> The variable k, referring to the tone location in an OFDM symbol, may be given as in Equation <NUM> and the variable m as in Equation <NUM>. <MAT> <MAT> Here, <MAT> may denote a number of resource blocks in the downlink. <MAT> may denote the number of subcarriers per resource block.

The location of the control tones may be defined. The variable bk denotes the transmitted tones that contain control information, the control tones may be located according to Equations <NUM> and <NUM>.

In this example, the control or pilot tones are transmitted after every four subcarriers. The overall sequence may generate time domain periodicity with a period length of <NUM> divided by four, which is <NUM> samples. The receiver (e.g., UE <NUM>) may get four periods of a time domain sequence where each period is multiplied with different phase noise. The UE <NUM> may measure an average phase difference between those received periods. This may yield a coarse estimation of the phase noise trajectory with a time resolution of <NUM> samples. If the power of the control tones is kept small relative to the power of the pilot tones, the UE <NUM> may estimate phase noise with a resolution of <NUM> samples based on this example periodicity. Lower resolutions may be achieved with algorithms of higher computational complexity. The UE <NUM> may estimate the channel after compensating for the phase noise.

A frequency of joint channel and PN estimation symbols in the time domain may vary in different examples. A number of control symbols per subframe may depend on a velocity of the receiving wireless device, a frequency of channel change, or combinations thereof. In one example, a symbol containing joint channel and PN estimation pilot is inserted every <NUM> for each UE. The relationship between the channel correlation and UE speed may be approximated by Clarke's model. Some examples handle approximately a speed of <NUM> kilometers per hour (km/hr).

The transmit power may be split between data and pilot tones. Phase noise may leak the contents of one town into a neighboring tone. If control tones have too much power, they may corrupt the content of one or more pilot tones due to the phase noise. On the other hand, control tones need to have sufficient power so that the receiver may demodulate them. Thus, the transmitter may allocate power among the control tones and the pilot tones to reduce this problem.

Further, a pilot sequence may have identification information embedded in it. For example, cell identification (ID) may be embedded in the pilot sequence so that the receiving wireless device can measure the interference from neighboring base stations. Alternatively, a beam ID may be embedded in the pilot sequence so that the receiving wireless device can decipher the beam ID that an interfering BS is using. In some examples, the pilot sequence includes the cell ID and the beam ID.

<FIG> illustrates another example control symbol <NUM> structure in accordance with various aspects of the present disclosure. The illustration of the control symbol <NUM> represents tones in a frequency domain. The control symbol <NUM> may be an example of the control symbol <NUM> described with reference to <FIG> and <FIG>.

The control symbol <NUM> may include pilot tones <NUM>. The pilot tones <NUM> may have a periodicity of five tones. A control symbol such as the control symbol <NUM> that only contains pilot tones may be occasionally transmitted. The frequency of transmitting such control symbols <NUM> may depend on a velocity of the wireless device and a frequency of channel change, or combinations thereof.

<FIG> shows a block diagram <NUM> of an example wireless device <NUM> that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a base station <NUM> described with reference to <FIG> and <FIG>. Wireless device <NUM> may include a BS receiver <NUM>, a BS control symbol component <NUM>-a, or a BS transmitter <NUM>. Wireless device <NUM> may also include a processor. Each of these components may be in communication with each other.

The BS receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to joint channel and phase noise estimation, etc.). Information may be passed on to the BS control symbol component <NUM>-a, and to other components of the wireless device <NUM>.

The BS control symbol component <NUM>-a may generate one or more control symbols that enable joint channel and phase noise estimation. The BS control symbol component <NUM>-a may insert a control tone at a first periodicity in a first subcarrier of a control symbol and insert a pilot tone at a second periodicity in a second subcarrier of the control symbol, the pilot tone being offset from the control tone in the control symbol. The BS control symbol component <NUM>-a may provide the generated control symbol to the BS transmitter <NUM>.

The BS transmitter <NUM> may transmit signals received from other components of the wireless device <NUM>. For example, the BS transmitter <NUM> may transmit control symbols. In some examples, the BS transmitter <NUM> may be collocated with the BS receiver <NUM> in a transceiver module. The BS transmitter <NUM> may include a single antenna, or it may include a plurality of antennas.

<FIG> shows a block diagram of another example wireless device <NUM>-a that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. The wireless device <NUM>-a may be an example of aspects of a wireless device <NUM> or a BS <NUM> described with reference to <FIG>, <FIG>, and <FIG>. The wireless device <NUM>-a may include a BS receiver <NUM>-a, a BS control symbol component <NUM>-b, or a BS transmitter <NUM>-a. The wireless device <NUM>-a may also include a processor. Each of these components may be in communication with each other. The BS control symbol component <NUM>-b may also include a BS control tone module <NUM>, a BS pilot tone module <NUM>, and a power component <NUM>.

The BS receiver <NUM>-a may receive information which may be passed on to BS control symbol component <NUM>-b, and to other components of wireless device <NUM>-a. The BS control symbol component <NUM>-b may perform the operations described with reference to <FIG>. The BS transmitter <NUM>-a may transmit signals received from other components of the wireless device <NUM>-a.

The BS control tone module <NUM> may insert a control tone at a first periodicity in a first subcarrier of a control symbol as described with reference to <FIG>. The BS control tone module <NUM> may also precode control information for the control tone with a discrete Fourier transform.

The BS pilot tone module <NUM> may insert a pilot tone at a second periodicity in a second subcarrier of the control symbol, the pilot tone being offset from the control tone in the control symbol as described with reference to <FIG>. In some examples, inserting the pilot tone at the second periodicity further includes inserting the pilot tone every nth subcarrier. In some examples, n is a value greater than one. In some examples, the at least two control symbols includes one symbol that consists of only pilot tones and null tones. The BS pilot tone module <NUM> may also determine a phase of a series of pilot tones based at least in part on a pseudo-noise sequence or a Zadoff-Chu sequence. The BS pilot tone module <NUM> may also determine a phase of a series of pilot tones based at least in part on a UE ID and a beam ID.

The power component <NUM> may transmit the control tone at a lower power than the pilot tone as described with reference to <FIG>.

The BS transmitter <NUM>-a may transmit the control symbol as described with reference to <FIG>. The BS transmitter <NUM>-a may also transmit at least two control symbols in a sub-frame, wherein the frequency of transmitting the at least two control symbols is based at least in part on a velocity of a wireless device and a frequency of channel change. The BS transmitter <NUM>-a may also transmit the control symbol within a millimeter wave (mmW) radio spectrum frequency. In some examples, the BS transmitter <NUM>-a is a mmW device.

<FIG> illustrates a block diagram of a system <NUM> including a BS <NUM>-b that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. System <NUM> may include BS <NUM>-b, which may be an example of a wireless device <NUM> or a base station <NUM> described with reference to <FIG>, <FIG>, and <FIG>. The BS <NUM>-b may include a BS control symbol component <NUM>-c, which may be an example of a BS control symbol component <NUM> described with reference to <FIG> and <FIG>. The BS <NUM>-b may also include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. For example, BS <NUM>-b may communicate bi-directionally with UE <NUM>-c or UE <NUM>-d.

In some cases, the BS <NUM>-b may have one or more wired backhaul links. The BS <NUM>-b may have a wired backhaul link (e.g., S1 interface, etc.) to the core network <NUM>. The BS <NUM>-b may also communicate with other BSs <NUM>, such as BS <NUM>-c and base station <NUM>-d via inter-base station backhaul links (e.g., an X2 interface). Each of the BSs <NUM> may communicate with UEs <NUM> using the same or different wireless communications technologies. In some cases, BS <NUM>-b may communicate with other base stations such as <NUM>-c or <NUM>-d utilizing base station communications module <NUM>. In some examples, base station communications module <NUM> may provide an X2 interface similar to that of a Long Term Evolution (LTE)/LTE-A wireless communication network technology to provide communication between some of the base stations <NUM>. In some examples, the BS <NUM>-b may communicate with other BSs <NUM> through the core network <NUM>. In some cases, the BS <NUM>-b may communicate with the core network <NUM> through network communications module <NUM>.

The BS <NUM>-b may include a processor <NUM>, memory <NUM> (including software (SW) <NUM>), transceiver <NUM>, and antenna(s) <NUM>, which each may be in communication, directly or indirectly, with one another (e.g., over bus system <NUM>). The transceivers <NUM> may be configured to communicate bi-directionally, via the antenna(s) <NUM>, with the UEs <NUM>, which may be multi-mode devices. The transceiver <NUM> (or other components of the BS <NUM>-b) may also be configured to communicate bi-directionally, via the antennas <NUM>, with one or more other BSs. The transceiver <NUM> may include a modem configured to modulate the packets and provide the modulated packets to the antennas <NUM> for transmission, and to demodulate packets received from the antennas <NUM>. The BS <NUM>-b may include multiple transceivers <NUM>, each with one or more associated antennas <NUM>. The transceiver <NUM> may be an example of a combined receiver <NUM> and transmitter <NUM> of <FIG> and <FIG>.

The memory <NUM> may include RAM and ROM. The memory <NUM> may also store computer-readable, computer-executable software code <NUM> containing instructions that are configured to, when executed, cause the processor <NUM> to perform various functions described herein (e.g., joint channel and phase noise estimation, selecting coverage enhancement techniques, call processing, database management, message routing, etc.). Alternatively, the software <NUM> may not be directly executable by the processor <NUM> but be configured to cause the computer (e.g., when compiled and executed) to perform functions described herein. The processor <NUM> may include an intelligent hardware device, e.g., a CPU, a microcontroller, an ASIC, and the like. The processor <NUM> may include various special purpose processors such as encoders, queue processing modules, base band processors, radio head controllers, digital signal processor (DSPs), and the like.

The BS communications module <NUM> may manage communications with other BSs <NUM>. In some cases, a communications management module may include a controller or scheduler for controlling communications with UEs <NUM> in cooperation with other base stations <NUM>. For example, the base station communications module <NUM> may coordinate scheduling for transmissions to UEs <NUM> for various interference mitigation techniques such as beamforming or joint transmission.

<FIG> shows a block diagram <NUM> of an example wireless device <NUM> that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. The wireless device <NUM> may be an example of aspects of a UE <NUM> described with reference to <FIG> and <FIG>. The wireless device <NUM> may include a UE receiver <NUM>, a control symbol component <NUM>-a, or a transmitter <NUM>. Wireless device <NUM> may also include a processor. Each of these components may be in communication with each other.

The UE receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to joint channel and phase noise estimation, etc.). Information may be passed on to the UE control symbol component <NUM>-a, and to other components of the wireless device <NUM>.

The UE control symbol component <NUM>-a may receive a control symbol comprising a control tone at a first periodicity, and a pilot tone at a second periodicity, the pilot tone being offset from the control tone in the control symbol. The UE control symbol component <NUM>-a may also perform a phase noise estimation and a channel estimation from the pilot tone.

The UE transmitter <NUM> may transmit signals received from other components of wireless device <NUM>. In some examples, the UE transmitter <NUM> may be collocated with the UE receiver <NUM> in a transceiver module. The UE transmitter <NUM> may include a single antenna, or it may include a plurality of antennas.

<FIG> shows a block diagram <NUM> of another example wireless device <NUM>-a that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. Wireless device <NUM>-a may be an example of aspects of a wireless device <NUM> or a UE <NUM> described with reference to <FIG>, <FIG>, and <FIG>. The wireless device <NUM>-a may include a UE receiver <NUM>-a, a UE control symbol component <NUM>-b, or a UE transmitter <NUM>-a. The wireless device <NUM>-a may also include a processor. Each of these components may be in communication with each other. The UE control symbol component <NUM>-b may also include a UE control tone module <NUM>, a UE pilot tone module <NUM>, and an estimation component <NUM>. In some examples, the wireless device comprises a millimeter wave (mmW) radio.

The UE receiver <NUM>-a may receive information which may be passed on to UE control symbol component <NUM>-b, and to other components of the wireless device <NUM>-a. The UE control symbol component <NUM>-b may perform the operations described with reference to <FIG>. The UE transmitter <NUM>-a may transmit signals received from other components of the wireless device <NUM>-a.

The UE control tone module <NUM> may interpret control tones included in a received control symbol such as the control symbol as described with reference to <FIG>. That is, the UE control tone module <NUM> may determine control information from the control tones. The UE pilot tone module <NUM> may interpret pilot tones included in a received control symbol as described with reference to <FIG>. The UE pilot tone module <NUM> may also determine a phase of a series of pilot tones based at least in part on a UE identification (ID) and a beam ID.

The estimation component <NUM> may estimate the phase noise from received control symbols as described with reference to <FIG>. After the phase noise compensation, the estimation component <NUM> may also perform the channel estimation. The estimation component <NUM> then determines the control information.

<FIG> illustrates a block diagram of a system <NUM> including a UE <NUM>-e that supports joint channel and phase noise estimation in accordance with various aspects of the present disclosure. The system <NUM> may include UE <NUM>-e, which may be an example of a wireless device <NUM> or a UE <NUM> described with reference to <FIG>, <FIG>, <FIG>, and <FIG>. The UE <NUM>-e may include a UE control symbol component <NUM>-c, which may be an example of a control symbol component <NUM> described with reference to <FIG>, <FIG>, and <FIG>. The UE <NUM>-e may also include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. For example, UE <NUM>-E may communicate bi-directionally with UE <NUM>-f or BS <NUM>-e.

UE <NUM>-E may also include a processor <NUM>, and memory <NUM> (including software (SW)) <NUM>, a transceiver <NUM>, and one or more antenna(s) <NUM>, each of which may communicate, directly or indirectly, with one another (e.g., via buses <NUM>). The transceiver <NUM> may communicate bi-directionally, via the antenna(s) <NUM> or wired or wireless links, with one or more networks, as described above. For example, the transceiver <NUM> may communicate bi-directionally with a base station <NUM> or another UE <NUM>. The transceiver <NUM> may include a modem to modulate the packets and provide the modulated packets to the antenna(s) <NUM> for transmission, and to demodulate packets received from the antenna(s) <NUM>. While UE <NUM>-e may include a single antenna <NUM>, the UE <NUM>-e may also have multiple antennas <NUM> capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory <NUM> may include random access memory (RAM) and read only memory (ROM). The memory <NUM> may store computer-readable, computer-executable software/firmware code <NUM> including instructions that, when executed, cause the processor <NUM> to perform various functions described herein (e.g., joint channel and phase noise estimation, etc.). Alternatively, the software/firmware code <NUM> may not be directly executable by the processor <NUM> but cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor <NUM> may include an intelligent hardware device, (e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc.).

<FIG> illustrates an example method <NUM> for joint channel and phase noise estimation in accordance with various aspects of the present disclosure. The operations of method <NUM> may be implemented by a BS <NUM>, a UE <NUM>, or their components as described with reference to <FIG>. For example, the operations of method <NUM> may be performed by the BS control symbol component <NUM> as described with reference to <FIG>, and <FIG>. In some examples, the BS <NUM> may execute a set of codes to control the functional elements of the BS <NUM> to perform the functions described below. Additionally or alternatively, the BS <NUM> may perform aspects the functions described below using special-purpose hardware.

At block <NUM>, the BS <NUM> may insert a control tone at a first periodicity in a first subcarrier of a control symbol as described with reference to <FIG>. In certain examples, the operations of block <NUM> may be performed by the BS control tone module <NUM> as described with reference to <FIG>.

At block <NUM>, the BS <NUM> may insert a pilot tone at a second periodicity in a second subcarrier of the control symbol, the pilot tone being offset from the control tone in the control symbol as described with reference to <FIG>. In certain examples, the operations of block <NUM> may be performed by the BS pilot tone module <NUM> as described with reference to <FIG>.

At block <NUM>, the BS <NUM> may transmit the control symbol as described with reference to <FIG>. In certain examples, the operations of block <NUM> may be performed by the BS transmitter <NUM> as described with reference to <FIG>.

<FIG> illustrates an example method <NUM> for joint channel and phase noise estimation in accordance with various aspects of the present disclosure. The operations of method <NUM> may be implemented by a UE <NUM> or its components as described with reference to <FIG>. For example, the operations of method <NUM> may be performed by the UE control symbol component <NUM> as described with reference to <FIG> and <FIG>. In some examples, a UE <NUM> may execute a set of codes to control the functional elements of the UE <NUM> to perform the functions described below. Additionally or alternatively, the UE <NUM> may perform aspects the functions described below using special-purpose hardware. The method <NUM> may also incorporate aspects of method <NUM> of <FIG>.

At block <NUM>, the UE <NUM> may receive a control symbol comprising a control tone at a first periodicity, and a pilot tone at a second periodicity, the pilot tone being offset from the control tone in the control symbol. In certain examples, the operations of block <NUM> may be performed by the UE receiver <NUM> as described with reference to <FIG>.

At block <NUM>, the UE <NUM> may perform performing a phase noise estimation and a channel estimation from the pilot tone as described with reference to <FIG>. In certain examples, the operations of block <NUM> may be performed by the estimation component <NUM> as described with reference to <FIG>.

Thus, methods <NUM> and <NUM> may provide for joint channel and phase noise estimation. It should be noted that methods <NUM> and <NUM> describe possible implementation, and that the operations and the steps may be rearranged or otherwise modified such that other implementations are possible. In some examples, aspects from two or more of the methods <NUM> and <NUM> may be combined.

The description herein provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims.

Techniques described herein may be used for various wireless communications systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. IS-<NUM> Releases <NUM> and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-<NUM> (TIA-<NUM>) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE <NUM> (WiFi), IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM™, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over an unlicensed and/or shared bandwidth. The description above, however, describes an LTE/LTE-A system for purposes of example, and LTE terminology is used in much of the description above, although the techniques are applicable beyond LTE/LTE-A applications.

The detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The terms "example" and "exemplary," when used in this description, mean "serving as an example, instance, or illustration," and not "preferred" or "advantageous over other examples.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

Also, as used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of" or "one or more of") indicates a disjunctive list such that, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

Claim 1:
A method (<NUM>) for wireless communication, comprising:
inserting (<NUM>) control tones (<NUM>) in a first plurality of subcarriers of a control symbol (<NUM>, <NUM>) at a first periodicity;
inserting (<NUM>) pilot tones (<NUM>) in a second plurality of subcarriers of the control symbol (<NUM>, <NUM>) at a second periodicity, the pilot tones (<NUM>) being offset from the control tones (<NUM>) in the control symbol (<NUM>, <NUM>), wherein the control symbol (<NUM>, <NUM>) includes alternating control tones (<NUM>) and pilot tones (<NUM>) separated by unoccupied subcarriers such that any occupied subcarrier in the control symbol (<NUM>, <NUM>) contains either a control tone (<NUM>) or a pilot tone (<NUM>); and
transmitting (<NUM>) the control symbol (<NUM>, <NUM>), wherein the control tones (<NUM>) are transmitted at a low power relative to the pilot tones (<NUM>).