Multi-phase frequency modulation for reduced peak deviation

Abstract

Aspects of the present disclosure provide techniques and apparatus for multi-phase frequency modulation. An example method of multi-phase frequency modulation includes determining a phase of a transmit signal based on constellation points; determining a code for frequency modulation based on the phase; generating a plurality of oscillation signals having different phases; efficiently phase-modulating the plurality of oscillating signals having the different phases based on the encoding for the frequency modulation; and selecting one of the plurality of phase-modulated oscillating signals.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Greek Patent Application No. 20220100752 filed on September 14, 2022, which is hereby incorporated herein by reference. Background Art Technical Field

[0003] Certain aspects of the present disclosure relate generally to electronic circuits and, more particularly, to techniques and apparatus for frequency modulation.

[0004] Related technologies

[0005] Electronic devices include traditional computing devices, such as desktop computers, notebook computers, tablet computers, smart phones, wearable devices such as smart watches, Internet servers, etc. These various electronic devices provide information, entertainment, social interaction, security, safety, productivity, transportation, manufacturing and other services for human users. Many functions of these various electronic devices rely on wireless communication. Wireless communication systems and devices are widely deployed to provide various types of communication content such as voice, video, packet data, message transceiving, broadcasting, etc. Wireless communication devices can send and / or receive radio frequency (RF) signals via any of various suitable radio access technologies (RATs), including but not limited to the fifth generation (5G) new radio (NR), long term evolution (LTE), code division multiple access (CDMA), time division multiple access (TDMA), broadband CDMA (WCDMA), global system for mobile (GSM), Bluetooth, Bluetooth low energy (BLE), ZigBee, wireless local area network (WLAN) RAT (e.g., IEEE 802.11), etc. In some cases, the transmitter may be implemented as a polar transmitter, where an in-phase / quadrature (I / Q) signal is converted to the polar domain as the amplitude and phase components of the signal. The amplitude and phase components are then used to generate a signal for transmission via a power amplifier. Summary of the invention

[0006] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desired characteristics. Without limiting the scope of the present disclosure as expressed by the claims that follow, some features will now be briefly discussed. After considering these discussions, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide various advantages, including reduced frequency modulation noise and improved wireless communication performance.

[0007] Certain aspects of the present disclosure provide a transmitter circuit. The transmitter circuit generally includes: a voltage controlled oscillator (VCO) configured to generate an oscillation signal; a modulation digital-to-analog converter (MDAC) having an output coupled to a control input of the VCO and configured to effectively modulate the phase of the oscillation signal; a multi-phase generator having an input coupled to the output of the VCO and configured to generate a plurality of oscillation signals having different phases from the phase-modulated oscillation signal; and a phase modulator having an input coupled to the output of the multi-phase generator and configured to select and output one of the plurality of oscillation signals.

[0008] Certain aspects of the present disclosure provide a method of wireless communication. The method generally includes: determining a phase of a transmitted signal based on a constellation point; determining a code for frequency modulation based on the phase; generating a plurality of oscillating signals with different phases; effectively phase modulating the plurality of oscillating signals with the different phases based on the code for the frequency modulation; and selecting one of the plurality of phase-modulated oscillating signals.

[0009] Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes: a component for determining a phase of a transmitted signal based on a constellation point; a component for determining a code for frequency modulation based on the phase; a component for generating a plurality of oscillating signals with different phases; a component for effectively phase modulating the plurality of oscillating signals with the different phases based on the code for the frequency modulation; and a component for selecting one of the plurality of phase modulated oscillating signals.

[0010] To achieve the foregoing and related ends, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail some illustrative features of one or more aspects. However, these features are merely indicative of some of the various ways in which the principles of the various aspects may be employed, and this specification is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to be able to understand in detail the manner in which the above-mentioned features of the present disclosure are achieved, a more specific description briefly summarized above can be obtained by reference to various aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the specification may admit to other equally effective aspects.

[0012] Figure 1 is a diagram of an example polar transmitter.

[0013] Figure 2 is a diagram illustrating an example of a transmitter circuit using multi-phase frequency modulation.

[0014] Figure 3 is a graph illustrating an example of multiple constellation points associated with an oscillating signal generated using multi-phase frequency modulation.

[0015] Figure 4A is a graph illustrating an example of frequency modulation over time using a single frequency modulation.

[0016] Figure 4B is a graph illustrating an example of frequency modulation over time using multi-phase frequency modulation.

[0017] Figure 5 is a flow chart of example operations for wireless communication using multi-phase frequency modulation.

[0018] Figure 6 is an illustration of a wireless communication network including wireless communication devices configured to perform multi-phase frequency modulation.

[0019] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0020] Certain aspects of the present disclosure relate to methods and apparatus for multi-phase frequency modulation.

[0021] Some wireless communication devices (such as Bluetooth devices, IEEE 802.11 devices, and / or other or future radio access technologies) may use polar coordinate transmitters, where in-phase / quadrature (I / Q) signals are converted to the polar coordinate domain as the magnitude and phase components of the signal. Since the frequency is the inverse of the period, the phase shift can be achieved by changing the frequency of the signal, so frequency modulation can be used to control the phase component. Frequency modulation can be achieved via a voltage-controlled oscillator (VCO), where a digital-to-analog converter (DAC) can control the output frequency of the VCO. The DAC can control the frequency shift in the oscillating signal generated by the VCO and can actually create a phase shift of up to ±180 degrees on the transmitted signal. In some cases, frequency modulation may introduce noise into the phase component, for example, due to inaccuracies in the digital-to-analog conversion applied to the VCO and / or frequency shifts at the VCO (which may be caused, for example, by temperature drift). Frequency modulation noise may translate into degraded wireless communication performance, such as increased adjacent channel power (e.g., increased self-interference or co-channel interference), increased latency, and / or reduced data rates.

[0022] Certain aspects of the present disclosure provide methods and apparatus for multi-phase frequency modulation (e.g., for a polar transmitter). A wireless communication device (e.g., a Bluetooth device and / or an IEEE 802.11 device) may include, for example, a polar transmitter in a transceiver (also referred to as a radio frequency front end (RFFE) circuit or an RF transceiver circuit) for transmitting and / or receiving RF signals. In some cases, the polar transmitter may use multiple phase shift stages to generate phase components. For example, a VCO may be controlled to output a signal at a frequency corresponding to a fine phase shift (e.g., ±45 degrees), and the output signal may be phase modulated to generate multiple signals at phases corresponding to different coarse phase shifts (e.g., 0 degrees, 90 degrees, 180 degrees, and / or 270 degrees) relative to the output signal, as described herein. Figures 1 to 3 Further description.

[0023] The methods and apparatus described herein for multiphase frequency modulation may provide various advantages. The methods and apparatus described herein may improve the wireless communication performance of a polar transmitter, thereby achieving reduced adjacent channel power (e.g., reduced interference), reduced latency, and / or increased data rates. The methods and apparatus described herein may reduce frequency modulation noise by reducing the maximum value of the frequency modulation adjusted using a DAC. In some cases, for example, the frequency modulation noise is reduced by 12 decibels, and the reduction in frequency modulation noise may improve the wireless communication performance of a polar transmitter.

[0024] Example RF Polar Transceiver

[0025] Figure 1 is an example polar coordinate transmitter 100, which may be implemented in a transceiver front end, such as described herein with respect to Figure 6 The wireless transceiver 622 is further described. The transceiver may use a baseband module to generate a baseband signal having an in-phase (I) and a quadrature (Q) component (I+jQ). The baseband signal may be provided to a polar coordinate processor 102, which may convert the baseband signal to a polar coordinate domain as a radius component 104 and a phase component 106, as illustrated. For example, assuming that the baseband signal is a complex signal (I+jQ), the polar coordinate components may be determined as follows:

[0026]

[0027] θ=arctan(Q / I) (1b)

[0028] Where r is the radius component and θ is the angular (phase) component. The radius component may correspond to the amplitude of the RF signal and the angular component may correspond to the phase of the RF signal, where the phase may be converted to an instantaneous frequency. The RF signal may be formed as the product of the radius signal and an oscillating signal (e.g., cos(t)) as follows:

[0029] s(t)=r(t)cos(2π·f c ·t+θ(t)) (2)

[0030] where s(t) is the transmitted RF signal, r(t) is the radius signal representing the radius component over time, and f c is the carrier frequency of the RF signal, and θ(t) is the phase of the RF signal and represents the angular component over time. The radius signal can be formed as a series of amplitudes corresponding to the radius component in expression (1a). In a frequency modulation embodiment, the phase signal can be formed as a series of frequency modulations, where each instantaneous frequency can correspond to a phase representing the angular component in expression (1b).

[0031] The radius component 104 (also referred to as the magnitude component) may be provided to an amplitude modulator 108. The amplitude modulator 108 generates a gain signal 110 (e.g., r(t)) and provides the gain signal 110 to a power amplifier (PA) 112. The gain signal 110 indicates the gain applied to the input signal (e.g., cos(2π·f c The gain signal 110 may represent the instantaneous amplitude corresponding to the radius component 104 .

[0032] Phase component 106 is provided to a phase modulator, which in some cases may be implemented as a frequency modulator 114. Frequency modulator 114 generates a phase signal 116 at an instantaneous frequency corresponding to the phase associated with phase component 106. Figure 2 Further described, frequency modulator 114 can use multiple stages of frequency modulation to generate phase signal 116, which can reduce noise generated by frequency modulation and improve wireless communication performance, such as improved data rate. Phase signal 116 is effectively multiplied by gain signal 110 using PA 112 to generate a radio frequency signal (e.g., s(t)) at the output of PA 112, which can be coupled to antenna 118 that transmits the radio frequency signal.

[0033] Although Figure 1 A polar transmitter in which certain aspects of the present disclosure may be implemented is provided as an example application to facilitate understanding, but certain aspects related to multi-phase frequency modulation described herein may be utilized in a variety of other suitable electronic systems.

[0034] Example of Multiphase Frequency Modulation

[0035] Figure 2is a diagram of an example of a transmitter circuit 200 using multi-phase frequency modulation. In this example, the transmitter circuit 200 may be a polar transmitter (e.g., polar transmitter 100) having an amplitude modulation circuit (e.g., amplitude modulator 108) and a multi-phase modulation circuit (e.g., frequency modulator 114).

[0036] The transmitting circuit 200 may include a modulator-demodulator (MODEM) 202 that modulates information into a complex signal (e.g., I(t)+jQ(t)), for example, into a series of complex symbols (e.g., I+jQ) that may correspond to constellation points, as described herein with respect to Figure 3 As further described. MODEM 202 may provide the complex signal to a coordinate rotation digital computer (CORDIC) 204, which converts the complex signal into a radius component and an angular component in the polar coordinate domain, for example, according to expressions (1a) and (1b). CORDIC 204 may provide the radius component and the angular component to an amplitude-modulation phase-modulation (AMPM) module 206. In some cases, CORDIC 204 may provide the radius component to the amplitude modulator 108. AMPM module 206 may determine the phase of the RF signal based on the corresponding angular component and the radius component, for example, so as to adjust the angular component to compensate for the AMPM distortion presented at PA 112. For example, AMPM module 206 may determine the instantaneous phase of the RF signal using a lookup table of pairs of radius components and angular components associated with corresponding phases. In some cases, the lookup table may provide a phase distortion at a specific magnitude, and AMPM module 206 may use the lookup table to determine a phase correction to compensate for the corresponding AMPM distortion. AMPM module 206 may provide the phase to differentiator 208.

[0037] Differentiator 208 may convert the phase into an instantaneous frequency having a period corresponding to the time delay of the phase. For example, differentiator 208 may receive a phase encoding and convert the phase encoding into a frequency encoding based on the phase encoding using differentiation. Differentiator 208 may provide the encoding for frequency modulation to bit splitter 210 (e.g., a frequency decoder). Differentiator 208 may have an output coupled to an input of bit splitter 210.

[0038] The bit splitter 210 may include a frequency decoder that converts a frequency code into a plurality of frequency modulation components, such as a fine frequency modulation code 212 and a coarse frequency modulation code 214. The bit splitter 210 may provide the fine frequency modulation code 212 to a modulation digital-to-analog converter (MDAC) 216 and provide the coarse frequency modulation code 214 to a phase modulator 224. The bit splitter 210 may have a first output coupled to an input of the MDAC 216 and a second output coupled to a control input of the phase modulator 224.

[0039] The frequency modulator 114 may perform phase modulation in a plurality of cascaded stages. In a first phase modulation stage, the frequency modulator 114 may, for example, use a voltage controlled oscillator (VCO) 218 ​​to effectively perform fine phase modulation, which generates an oscillation signal within a fine phase range (e.g., ±45 degrees). In a second phase modulation stage, the frequency modulator 114 may effectively perform coarse phase modulation, which generates a plurality of oscillation signals at different phases (e.g., 0 degrees, 90 degrees, 180 degrees, and 270 degrees) from the oscillation signal output at the first phase modulation stage, and the frequency modulator 114 may select one of the oscillation signals having coarse phase modulation. For example, the frequency modulator 114 may perform coarse phase modulation using a multiphase generator 220 that generates a plurality of oscillation signals at different phases and a phase modulator 224 that selects one of the oscillation signals, as further described herein.

[0040] The VCO 218 may generate an oscillating signal in response to a control signal output by the MDAC 216, which may have an output coupled to a control input of the VCO 218. In some cases, the VCO 218 may be part of a phase-locked loop (PLL) circuit (such as a delta-sigma fractional-N phase-locked loop) for controlling a tuning voltage of the VCO to control the frequency of the oscillating signal relative to a reference clock. The MDAC 216 may effectively modulate the phase (e.g., ±45 degrees) of the oscillating signal output by the VCO 218 based on a control signal representing a frequency modulation associated with the fine frequency modulation code 212. In some cases, the MDAC 216 may output a control signal at a specific voltage that adjusts the output frequency of the VCO 218. In some cases, the VCO 218 may be implemented as a resonator, such as an inductor-capacitor (LC) resonator, and the MDAC 216 may adjust the capacitance of the LC resonator to change the output frequency of the VCO 218.

[0041] Assuming that the multi-phase generator 220 generates a number (N) of oscillation signals having different phases, the MDAC 216 may control the VCO 218 to effectively modulate the phase of the oscillation signal by (±180 / N)°. For example, the MDAC 216 may output a control signal at a specific voltage that causes the VCO 218 to output an oscillation signal at a frequency corresponding to the phase associated with the fine frequency modulation code 212. The VCO 218 may provide the modulated oscillation signal to the multi-phase generator 220. For example, the VCO 218 may have an output portion coupled to the multi-phase generator 220.

[0042] The multiphase generator 220 may generate a plurality of oscillating signals 222 having different phases than the effectively phase-modulated oscillating signals generated by the VCO 218. The multiphase generator 220 may have an input coupled to an output of the VCO 218, and the multiphase generator 220 may provide the oscillating signals to the phase modulator 224. The multiphase generator 220 may generate a plurality (N) of oscillating signals having different phases, wherein the different phases are incremented by (360 / N)°, and the VCO 218 may be controlled to effectively modulate the phases of the oscillating signals by (±180 / N)°. For example, the multiphase generator 220 may generate four oscillating signals 222 (e.g., 0 degrees, 90 degrees, 180 degrees, and 270 degrees) having a phase increment of 90°, wherein a first oscillating signal corresponds to 0 degrees, a second oscillating signal corresponds to 90 degrees, a third oscillating signal corresponds to 180 degrees, and a fourth oscillating signal corresponds to 270 degrees. In such cases, MDAC 216 may control VCO 218 to effectively modulate the phase of the oscillating signal by ±45°.

[0043] The multiphase generator 220 may include one or more frequency dividers that output oscillating signals 222 at different phases. For example, the multiphase generator 220 may have a frequency divider circuit that outputs an oscillating signal at 0 degrees (e.g., no phase shift to the oscillating signal output by the VCO 218), outputs an oscillating signal at 90 degrees, outputs an oscillating signal at 180 degrees, and outputs an oscillating signal at 270 degrees. As an example, a divide-by-two frequency divider may generate an I component and a Q component and an inverted I component and Q component such that the frequency divider outputs four phases (e.g., 0 degrees, 90 degrees, 180 degrees, and 270 degrees). It will be understood that the frequency divider is merely an example, and other circuits may be used to generate oscillating signals at different phases, such as a time delay circuit.

[0044] The phase modulator 224 may select and output one of the plurality of oscillating signals 222 received from the multiphase generator 220. The coarse frequency modulation code 214 may control the selection of one of the plurality of oscillating signals 222 by the phase modulator. For example, the coarse frequency modulation code 214 may indicate to the phase modulator 224 which one of the oscillating signals 222 to select and output. In some cases, the phase modulator 224 may include a multiplexer that selects an oscillation among the oscillating signals 222 for output. The phase modulator 224 may have an input coupled to the output of the multiphase generator 220. The phase modulator 224 may provide the selected oscillating signal to an amplifier, such as the PA 112.

[0045] PA 112 may amplify the selected oscillating signal for transmission via antenna 118. PA 112 may have an input coupled to the output of the phase modulator and an output coupled to antenna 118.

[0046] In some cases, the transmitter circuit 200 may include digital circuits and / or analog circuits. For example, the MODEM 202, CORDIC 204, AMPM module 206, differentiator 208, and bit splitter 210 may be implemented as digital circuits, such as a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), discrete gate or transistor logic, etc. The VCO 218 and the multi-phase generator 220 may be implemented as analog circuits.

[0047] Figure 3 3 is a graph illustrating an example of a plurality of constellation points 302a-302d (collectively referred to as constellation points 302) associated with an oscillating signal generated using multi-phase frequency modulation as described herein. As used herein, a constellation point may represent the symbol of a signal as a complex component (e.g., I+jQ) in a polar domain, where an angular component may correspond to the phase of the signal and a radial component may correspond to the amplitude of the signal. Constellation point 302 represents one of N constellation points that may be output using multi-phase frequency modulation and amplitude modulation of a polar transmitter, such as transmitter circuit 200. For example, the radial component of constellation point 302 is an example of an RF signal after amplitude modulation is performed at PA 112. Each of constellation points 302 may have a corresponding radial component 304a-304d and a corresponding angular component 306a-306d. A first constellation point 302a may have a first radial component 304a and a first angular component 306a. The second constellation point 302b may have a second radial component 304b and a second angular component 306b; and so on for the other constellation points 302c, 302d.

[0048] In this example, since one of the coarse phase modulations may apply a zero degree phase, the first constellation point 302a may effectively represent the fine phase modulation applied using the VCO 218, and the other constellation points 302b-302d may represent the coarse phase modulation applied using the multiphase generator 220. For example, the first angular component 306a may be 30 degrees, and the other angular components 304b-304d may be incremented from 30 degrees by 90 degrees (e.g., 120 degrees, 210 degrees, and 300 degrees, respectively). The phase modulator 224 may select one of the oscillating signals to output one of the constellation points 302 associated with the corresponding phase component of the complex signal for transmission, for example, determined at the CORDIC 204 and / or the AMPM module 206. In this way, using both fine and coarse frequency modulation, the phase component of any desired constellation point for the complex signal for transmission may be achieved. It will be understood that four constellation points are merely examples, and that the multi-phase frequency modulation described herein may generate two or more oscillating signals at different phases corresponding to two or more constellation points (eg, >4 constellation points).

[0049] Figure 4A 4 is a graph illustrating an example of frequency modulation over time using a single frequency modulation. In this example, the frequency modulation generates an effective phase modulation across a phase range 402 including 0 degrees to 360 degrees (e.g., from 0 degrees ±180 degrees). For example, due to the inaccuracy of the control signal of the VCO representing the correct phase of the angular component associated with the constellation point, performing phase modulation across the phase range 402 may generate noise in the transmitted RF signal. In addition, such a large phase modulation of ±180 degrees may result in a more complex MDAC design, which may have a larger footprint.

[0050] Figure 4B 4 is a graph illustrating an example of frequency modulation over time using multi-phase frequency modulation. In this example, the frequency modulation uses fine phase modulation across a phase range 404 (e.g., ±180 / N degrees) and coarse phase modulation using a multi-phase generator to generate an effective phase modulation, as described herein with respect to Figure 2 In such cases, Figure 4A The control signal for the VCO may represent a smaller phase range 404 than the phase modulation performed at the VCO, and thus, the multi-phase frequency modulation may reduce the noise generated from the frequency modulation. For example, the control signal may be able to more accurately represent the angular component associated with the desired constellation point for transmission, where fine tuning of the effective phase modulation is performed at the VCO. In addition, such smaller phase modulation may allow for a simpler MDAC design, which may have a smaller footprint.

[0051] Figure 5 5 is a flow chart of example operations 500 for wireless communication. Operations 500 may be performed by a transmitter (such as transmitter circuit 200). Operations 500 may be implemented as a processor (e.g., Figure 6 The software components (e.g., computer executable code or instructions) executed and run on the processor 608 or the signal processor 618 of ... Figure 1 In some aspects, the transmission of the signal by the transmitter can be implemented via a bus interface of a circuit (eg, a radio frequency integrated circuit) that obtains and / or outputs the signal.

[0052] Operations 500 may optionally begin at block 502, where the transmitter circuit may determine a phase of a transmit signal based on a constellation point (e.g., constellation point 302a). For example, the transmitter circuit may determine an angular component associated with the constellation point (e.g., angular component 306a) and apply the angular component as the phase of the transmit signal, as described herein with respect to expression (1b).

[0053] At block 504, the transmitter circuit may determine a code for frequency modulation based on the phase. For example, to determine the code for frequency modulation, the transmitter circuit may generate a fine frequency modulation code (e.g., fine frequency modulation code 212) for input to an MDAC (e.g., MDAC 216) or to control effective phase modulation, and the transmitter circuit may generate a coarse frequency modulation code (e.g., coarse frequency modulation code 214) for controlling a phase modulator (e.g., phase modulator 224) or selecting an oscillating signal among a plurality of oscillating signals with different phases. In some aspects, to determine the code for frequency modulation, the transmitter circuit may differentiate the phase of the transmit signal, for example, to convert the phase to an instantaneous frequency.

[0054] At block 506, the transmitter circuit may generate a plurality of oscillating signals having different phases. The transmitter circuit may generate a plurality (N) of oscillating signals having different phases, wherein the different phases are in increments of (360 / N) degrees, for example, as described herein with respect to Figure 2 and Figure 3 To generate an oscillation signal, the transmitter circuit may perform multi-level phase modulation. For example, the transmitter circuit may control a VCO (eg, VCO 218) to generate an oscillation signal, and the transmitter circuit may divide the oscillation signal to generate several (N) oscillation signals having different phases.

[0055] At block 508, the transmitter circuit may effectively phase modulate multiple oscillating signals having different phases based on the code for frequency modulation. The transmitter circuit may effectively phase modulate the multiple oscillating signals by (±180 / N)°. To effectively phase modulate the oscillating signals, the transmitter circuit may maintain a phase separation of (360 / N)° between the oscillating signals having different phases. In certain aspects, the transmitter circuit may use an MDAC to control a VCO to effectively modulate the phase of the oscillating signal by (±180 / N)°. The fine frequency modulation code may control the effective phase modulation. For example, the fine frequency modulation code may indicate an instantaneous frequency to be output using the VCO, and the frequency may be converted into a control voltage applied to a control input of the VCO.

[0056] At block 510, the transmitter circuit may select one of the plurality of phase modulated oscillating signals, for example using a phase modulator. In certain aspects, the coarse frequency modulation encoding may indicate the selection of the oscillating signal among the phase modulated oscillating signals. The transmitter circuit may select one of the plurality of phase modulated oscillating signals having a modulated phase that is closest to a constellation point.

[0057] In some aspects, the transmitter circuit can perform multi-level phase modulation, for example, as described herein with respect to Figure 2As an example, in a first phase modulation stage, the transmitter circuit may effectively phase modulate the oscillating signal by ±45°, and in a second phase modulation stage, the transmitter circuit may generate four oscillating signals having a phase increment of 90° relative to the oscillating signal.

[0058] For certain aspects, the transmitter circuit may amplify a selected one of a plurality of phase modulated oscillating signals, process the amplified signal (e.g., amplitude modulate, filter, and / or perform impedance matching on the amplified signal), and transmit the processed signal as a transmit signal, e.g., via antenna 118.

[0059] Example Wireless Communication Network

[0060] In certain aspects, apparatus and methods for multi-phase frequency modulation may be used in certain wireless communication devices in a wireless network. Figure 6 is a diagram of a wireless communication network 600 including a wireless communication device 602 having a wireless transceiver 622, which may include Figure 2 In some aspects, the wireless transceiver 622 can be configured to perform multi-phase frequency modulation, for example, as described herein with respect to Figures 2 to 5 as described.

[0061] In the wireless communication network 600, the wireless communication device 602 can communicate with other wireless communication devices 604a-604d (e.g., base station 604a, access point 604b, wireless headset 604c, or cellular phone 604d) via one or more wireless links 606. As shown, the wireless communication device 602 is depicted as a smart phone. However, the wireless communication device 602 can be implemented as any suitable computing or other electronic device, such as a cellular base station, a broadband router, an access point, a cellular or mobile phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a server computer, a network attached storage (NAS) device, a smart appliance, a communication system based on a vehicle, an Internet of Things (IoT) device, a sensor or security device, an asset tracker, etc. In some cases, the transmitter circuit 200 can be implemented in other wireless communication devices 604a-604d.

[0062] As an example, the base station 604a communicates with the wireless communication device 602 via a wireless link 606, which can be implemented as any suitable type of wireless link. Although depicted as a base station tower of a cellular radio network, the base station 604a can represent or be implemented as another device, such as any of other wireless communication devices 604b-604d, a satellite, a terrestrial broadcast tower, an access point (e.g., access point 604b), a peer device (e.g., a wireless headset 604c or a cellular phone 604d), a mesh network node, a fiber optic line, another electronic device substantially as described above, etc. Thus, the wireless communication device 602 can communicate with the base station 604a or another device (e.g., any of the other wireless communication devices 604b-604d) via a wired connection, a wireless connection, or a combination thereof. The wireless link 606 can include a downlink of data or control information communicated from the base station 604a to the wireless communication device 602, and an uplink of other data or control information communicated from the wireless communication device 602 to the base station 604a. Wireless link 606 may use any suitable communication protocol or standard (such as 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), 3GPP New Radio 5th Generation (NR 5G), IEEE 802.11 (WiFi), IEEE 802.16 (WiMAX), Bluetooth TM etc.) to achieve this.

[0063] The wireless communication device 602 includes a processor 608 and a memory 610. The memory 610 may be part of or form part of a computer-readable storage medium. The processor 608 may include any type of processor configured to execute processor-executable instructions (e.g., code) stored by the memory 610, such as an application processor or a multi-core processor. The memory 610 is configured to store instructions (e.g., computer-executable code or instructions) that, when executed by the processor 608, cause the processor 608 to perform operations for multi-phase frequency modulation (such as relative to Figure 5 The memory 610 may include any suitable type of data storage medium, such as volatile memory (e.g., random access memory (RAM)), non-volatile memory (e.g., flash memory), optical media, magnetic media (e.g., disk or tape), etc. In the context of the present disclosure, the memory 610 is implemented to store instructions 612, data 614, and other information for the wireless communication device 602, and thus when configured as a computer-readable storage medium or a portion thereof, the memory 610 does not include transient propagating signals or carrier waves. The memory 610 may include non-transitory computer-readable media (e.g., tangible media).

[0064] The wireless communication device 602 may also include input / output ports 616. The I / O ports 616 enable data exchange or interaction with other devices, networks, or users, or between components of the device.

[0065] The wireless communication device 602 may also include a signal processor (SPC) 618, such as, for example, a digital signal processor (DSP). The signal processor 618 may function similarly to the processor 608 and may be capable of executing instructions and / or processing information in conjunction with the memory 610.

[0066] For communication purposes, the wireless communication device 602 also includes a modem 620, a wireless transceiver 622, and an antenna (not shown). The wireless transceiver 622 uses radio frequency (RF) wireless signals to provide connectivity to a corresponding network and other wireless communication devices connected thereto. The wireless transceiver 622 may include the Figure 2 Circuits for multiphase frequency modulation are described, such as transmitter circuit 200. Wireless transceiver 622 may facilitate communications over any suitable type of wireless network, such as a wireless local area network (WLAN), a peer-to-peer (P2P) network, a mesh network, a cellular network, a wireless wide area network (WWAN), a navigation network (e.g., a Global Positioning System (GPS) or another Global Navigation Satellite System (GNSS) for North America), and / or a wireless personal area network (WPAN).

[0067] The various operations of the above methods may be performed by any suitable component capable of performing the corresponding functions. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. For example, the component for determining may include a modem (e.g., modem 202), a processor (e.g., polar coordinate processor 102, CORDIC 204, processor 608, and / or signal processor 618), a memory (e.g., memory 610), an AMPM module (e.g., AMPM module 206), a differentiator (e.g., differentiator 208), and / or a bit splitter (e.g., bit splitter 210). The component for generating, phase modulating, selecting, and / or amplifying the oscillating signal may include an MDAC (e.g., MDAC 216), a VCO (e.g., VCO 218), a multiphase generator (e.g., multiphase generator 220), a phase modulator (e.g., phase modulator 224), and / or an amplifier (e.g., PA 112).

[0068] Based on the present disclosure, it should be understood that the apparatus and method for multiphase frequency modulation described herein provide various advantages. The method and apparatus described herein can improve the wireless communication performance of a polar coordinate transmitter, thereby achieving reduced adjacent channel power, reduced latency, and / or increased data rate. The method and apparatus described herein can reduce the maximum value of the frequency modulation adjusted by the DAC, and in some cases, the frequency modulation noise can be reduced by 12 decibels. The reduction in frequency modulation noise can improve the wireless communication performance of a polar coordinate transmitter.

[0069] Example aspects

[0070] In addition to the above-mentioned various aspects, specific combinations of the various aspects are also within the scope of the present disclosure, and the details of some of the specific combinations are as follows:

[0071] Aspect 1: A transmitter circuit for wireless communication, the transmitter circuit comprising: a voltage controlled oscillator (VCO), the voltage controlled oscillator (VCO) being configured to generate an oscillation signal; a modulation digital-to-analog converter (MDAC), the modulation digital-to-analog converter (MDAC) having an output coupled to a control input of the VCO and being configured to effectively modulate the phase of the oscillation signal; a multi-phase generator, the multi-phase generator having an input coupled to the output of the VCO and being configured to generate a plurality of oscillation signals with different phases from a phase-modulated oscillation signal; and a phase modulator, the phase modulator having an input coupled to the output of the multi-phase generator and being configured to select and output one of the plurality of oscillation signals.

[0072] Aspect 2: The transmitter circuit according to aspect 1, wherein the multi-phase generator is configured to generate a number (N) of the oscillation signals having the different phases, and wherein the different phases are in increments of (360 / N)°.

[0073] Aspect 3: The transmitter circuit according to aspect 2, wherein the MDAC is configured to control the VCO to effectively modulate the phase of the oscillation signal by (±180 / N)°.

[0074] Aspect 4: A transmitter circuit according to any one of Aspects 1 to 3, wherein the multi-phase generator is configured to generate four oscillation signals with a phase increment of 90°, and wherein the MDAC is configured to control the VCO to effectively modulate the phase of the oscillation signal by ±45°.

[0075] Aspect 5: A transmitter circuit according to any one of Aspects 1 to 4, wherein the transmitter circuit also includes a bit splitter having a first output coupled to an input of the MDAC and a second output coupled to a control input of the phase modulator, wherein the bit splitter is configured to receive a code for frequency modulation and generate a fine frequency modulation code for the MDAC and a coarse frequency modulation code for the phase modulator.

[0076] Aspect 6: The transmitter circuit according to aspect 5, wherein the coarse frequency modulation encoding is configured to control selection of the one of the plurality of oscillating signals by the phase modulator.

[0077] Aspect 7: According to the transmitter circuit of Aspect 5 or 6, the transmitter circuit also includes a differentiator having an output portion coupled to the input portion of the bit splitter and configured to receive a phase code and use differentiation based on the phase code to generate the code for the frequency modulation.

[0078] Aspect 8: According to any one of Aspects 1 to 7, the transmitter circuit also includes an amplifier having an input portion coupled to the output portion of the phase modulator and configured to amplify the one of the multiple oscillation signals selected and output by the phase modulator for transmission.

[0079] Aspect 9: The transmitter circuit according to any one of aspects 1 to 9, wherein the multi-phase generator includes a frequency divider.

[0080] Aspect 10: A method of wireless communication, the method comprising: determining a phase of a transmitted signal based on a constellation point; determining a code for frequency modulation based on the phase; generating a plurality of oscillation signals with different phases; effectively phase modulating the plurality of oscillation signals with the different phases based on the code for the frequency modulation; and selecting one of a plurality of phase-modulated oscillation signals.

[0081] Aspect 11: The method according to aspect 10, wherein the generating comprises generating a number (N) of the oscillation signals having the different phases, and wherein the different phases are in increments of (360 / N)°.

[0082] Aspect 12: The method according to aspect 11, wherein the effective phase modulation comprises effectively phase modulating the plurality of oscillation signals by (±180 / N)°.

[0083] Aspect 13: The method according to aspect 11 or 12, wherein the effective phase modulation includes maintaining a phase separation of (360 / N)° between the oscillating signals having the different phases.

[0084] Aspect 14: The method according to any one of aspects 10 to 13, wherein the generating comprises generating four oscillating signals with a phase increment of 90°, and wherein the effective phase modulation comprises effectively phase modulating the plurality of oscillating signals by ±45°.

[0085] Aspect 15: A method according to any one of Aspects 10 to 14, wherein the generating comprises: controlling a voltage-controlled oscillator (VCO) to generate an oscillation signal; and dividing the frequency of the oscillation signal to generate a plurality (N) of the oscillation signals having the different phases.

[0086] Aspect 16: The method according to aspect 15, wherein the effective phase modulation includes using a modulation digital-to-analog converter (MDAC) to control the VCO to effectively modulate the phase of the oscillation signal by (±180 / N)°.

[0087] Aspect 17: A method according to Aspect 16, wherein determining the code for the frequency modulation includes: generating a fine frequency modulation code for input to the MDAC; and generating a coarse frequency modulation code for controlling a phase modulator, wherein the selection includes using the phase modulator to select the one of the multiple oscillation signals.

[0088] Aspect 18: The method according to any one of Aspects 10 to 16, wherein determining the code for the frequency modulation comprises: generating a fine frequency modulation code for controlling the effective phase modulation; and generating a coarse frequency modulation code for controlling the selection.

[0089] Aspect 19: The method according to any one of aspects 10 to 18, wherein determining the code for the frequency modulation comprises differentiating the phase of the transmit signal.

[0090] Aspect 20: According to the method of any one of Aspects 10 to 19, the method further includes: amplifying the selected one of the plurality of phase-modulated oscillation signals; processing the amplified signal; and transmitting the processed signal as the transmission signal.

[0091] Aspect 21: The method according to any one of aspects 10 to 20, wherein the selecting comprises selecting the one of the plurality of phase-modulated oscillating signals having a modulated phase that is closest to the constellation point.

[0092] Aspect 22: An apparatus for wireless communication, the apparatus comprising: a component for determining a phase of a transmitted signal based on a constellation point; a component for determining a code for frequency modulation based on the phase; a component for generating a plurality of oscillation signals with different phases; a component for effectively phase-modulating the plurality of oscillation signals with the different phases based on the code for the frequency modulation; and a component for selecting one of a plurality of phase-modulated oscillation signals.

[0093] Aspect 23: A device comprising: a memory comprising computer-executable instructions; and one or more processors configured to execute the computer-executable instructions and cause the device to perform a method according to any one of Aspects 10 to 21.

[0094] Aspect 24: An apparatus, comprising: a circuit, the circuit being configured to perform the method according to any one of aspects 10 to 21.

[0095] Aspect 25: An apparatus comprising means for performing the method according to any one of aspects 10 to 21.

[0096] Aspect 26: A non-transitory computer-readable medium comprising computer-executable instructions, which, when executed by one or more processors of a processing system, cause the processing system to perform the method according to any one of aspects 10 to 21.

[0097] Aspect 27: A computer program product embodied on a computer-readable storage medium, the computer program product comprising code for executing the method according to any one of aspects 10 to 21.

[0098] Additional considerations

[0099] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limited to the scope, applicability or aspects set forth in the claims. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various procedures or components as appropriate. For example, the described methods may be performed in an order different from the order described, and various actions may be added, omitted or combined. In addition, the features described for some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionality or structures and functionality that are supplementary or alternative to the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the present claims.

[0100] The various illustrative logic blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or performed using a general purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC), or any other such configuration.

[0101] As used herein, a signal may refer to a detectable physical quantity or pulse (such as voltage, current, or magnetic field strength over time) through which a message or information may be transmitted. A signal may carry information that can be used for observation.

[0102] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items (including single members). For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0103] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or other data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Furthermore, "determining" may include resolving, selecting, choosing, establishing, etc.

[0104] The method disclosed herein includes one or more actions for implementing the method. The method actions may be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and / or use of specific actions may be modified without departing from the scope of the claims. In addition, the various operations of the method described above may be performed by any appropriate component capable of performing the corresponding function. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors.

[0105] The following claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language of the claims. Within the claims, unless otherwise specified, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. Any claim element is not interpreted according to the provisions of 35 U.S.C. § 112 (f) unless the element is explicitly stated using the phrase "parts for...". All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure that are known or will be known later to a person of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims.

Claims

1. A transmitter circuit for wireless communication, the transmitter circuit comprising: a voltage controlled oscillator (VCO) configured to generate an oscillation signal; a modulated digital-to-analog converter (MDAC) having an output coupled to a control input of the VCO and configured to effectively modulate a phase of the oscillating signal; a multi-phase generator having an input coupled to an output of the VCO and configured to generate a plurality of oscillation signals having different phases from the phase-modulated oscillation signal; and A phase modulator has an input coupled to the output of the multi-phase generator and is configured to select and output one of the plurality of oscillation signals.

2. The transmitter circuit of claim 1, wherein the multiphase generator is configured to generate a number (N) of the oscillation signals having the different phases, and wherein the different phases are in increments of (360 / N)°. 3 . The transmitter circuit of claim 2 , wherein the MDAC is configured to control the VCO to effectively modulate the phase of the oscillating signal by (±180 / N)°.

4. The transmitter circuit of claim 1 , wherein the multiphase generator is configured to generate four oscillating signals with phase increments of 90°, and wherein the MDAC is configured to control the VCO to effectively modulate the phases of the oscillating signals by ±45°.

5. The transmitter circuit of claim 1 , further comprising a bit splitter having a first output coupled to an input of the MDAC and a second output coupled to a control input of the phase modulator, wherein the bit splitter is configured to receive a code for frequency modulation and generate a fine frequency modulation code for the MDAC and a coarse frequency modulation code for the phase modulator.

6. The transmitter circuit of claim 5, wherein the coarse frequency modulation encoding is configured to control selection of the one of the plurality of oscillating signals by the phase modulator.

7. The transmitter circuit of claim 5, further comprising a differentiator having an output coupled to an input of the bit splitter and configured to receive a phase encoding and generate the encoding for the frequency modulation using differentiation based on the phase encoding.

8. The transmitter circuit of claim 1 , further comprising an amplifier having an input coupled to an output of the phase modulator and configured to amplify the one of the plurality of oscillation signals selected and output by the phase modulator for transmission.

9. The transmitter circuit of claim 1, wherein the multiphase generator comprises a frequency divider.

10. A method of wireless communication, the method comprising: determining a phase of a transmitted signal based on the constellation point; determining a code for frequency modulation based on the phase; generating a plurality of oscillation signals having different phases; effectively phase modulating the plurality of oscillating signals having the different phases based on the encoding for the frequency modulation; as well as One of a plurality of phase modulated oscillating signals is selected.

11. The method of claim 10, wherein the generating comprises generating a number (N) of the oscillation signals having the different phases, and wherein the different phases are in increments of (360 / N)°.

12. The method of claim 11, wherein effectively phase modulating comprises effectively phase modulating the plurality of oscillating signals by (±180 / N)°.

13. The method of claim 11, wherein the effective phase modulation comprises maintaining a phase separation of (360 / N)° between the oscillating signals having the different phases.

14. The method of claim 10, wherein the generating comprises generating four oscillating signals having a phase increment of 90°, and wherein the effective phase modulation comprises effectively phase modulating the plurality of oscillating signals by ±45°.

15. The method of claim 10, wherein said generating comprises: controlling a voltage controlled oscillator (VCO) to generate an oscillation signal; as well as The oscillation signal is frequency-divided to generate a plurality (N) of the oscillation signals having the different phases.

16. The method of claim 15, wherein the effective phase modulation comprises using a modulation digital-to-analog converter (MDAC) to control the VCO to effectively modulate the phase of the oscillating signal by (±180 / N)°.

17. The method of claim 16, wherein determining the code for the frequency modulation comprises: generating a fine frequency modulation code for input to the MDAC; as well as A coarse frequency modulation code is generated for controlling a phase modulator, wherein the selecting comprises selecting the one of the plurality of oscillating signals using the phase modulator.

18. The method of claim 10, wherein determining the code for the frequency modulation comprises: generating a fine frequency modulation code for controlling the effective phase modulation; as well as A coarse frequency modulation code is generated for controlling the selection.

19. The method of claim 10, wherein determining the code for the frequency modulation comprises differentiating the phase of the transmit signal.

20. The method according to claim 10, further comprising: amplifying a selected one of the plurality of phase modulated oscillating signals; processing the amplified signal; as well as The processed signal is transmitted as the transmission signal.

21. The method of claim 10, wherein the selecting comprises selecting the one of the plurality of phase-modulated oscillating signals having a modulated phase that is closest to the constellation point.

22. An apparatus for wireless communication, the apparatus comprising: means for determining a phase of a transmit signal based on a constellation point; means for determining a code for frequency modulation based on said phase; means for generating a plurality of oscillating signals having different phases; means for effectively phase modulating said plurality of oscillating signals having said different phases based on said encoding for said frequency modulation; and Means for selecting one of a plurality of phase modulated oscillating signals.

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