HK1129267B

HK1129267B - Method and system for processing communication signals

Info

Publication number: HK1129267B
Application number: HK09106623.3A
Authority: HK
Inventors: 阿玛德雷兹．罗弗戈兰
Original assignee: 美国博通公司
Priority date: 2007-07-31
Filing date: 2009-07-21
Publication date: 2012-05-11

Description

Method and system for processing communication signal

Technical Field

More particularly, certain embodiments of the invention relate to a method and system for polar modulation with discontinuous phase for an RF transmitter with power control.

Background

The relationship between polar modulation and in-phase (I) and quadrature (Q) modulation is similar to the relationship between polar and cartesian coordinate systems. For polar modulation, the I and Q components of the RF signal, which are orthogonal to each other, are vector representations that are converted to include an amplitude component and a phase component. In this way, a composite I and Q signal can be generated with one phase change and one amplitude change, while separate I and Q modulations, especially for non-constant envelope modulation modes, require amplitude and phase modulation for each channel. In addition, the I and Q modulation schemes require high linearity of the power amplifier, which often results in power inefficient designs that are subject to parameter variations due to factors such as temperature. In contrast, polar modulation may use efficient and non-linear amplifier designs for non-constant envelope modulation modes.

Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.

Disclosure of Invention

A method and/or system for polar modulation with discontinuous phase for an RF transmitter with power control functionality, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.

According to an aspect of the present invention, there is provided a method of processing a communication signal, comprising:

amplifying a signal using a plurality of amplifiers such that a combined gain of the plurality of amplifiers includes a coarse amplitude gain (coarse amplitude gain), a power level gain (power level gain), and an amplitude offset gain (amplitude offset gain);

adjusting a gain of one or more of the plurality of amplifiers to set the coarse amplitude gain and the power level gain; and

adjusting a gain of one or more remaining amplifiers of the plurality of amplifiers to set the amplitude offset gain.

Preferably, the method comprises dynamically adjusting the settings of the coarse amplitude gain, power level gain and/or amplitude offset gain.

Preferably, the method comprises adaptively adjusting the settings of the coarse amplitude gain, power level gain and/or amplitude offset gain.

Preferably, the method comprises switching (switching) the gain of one or more of the plurality of amplifiers associated with the coarse amplitude gain between unity gain and an arbitrary fixed gain.

Preferably, the gain of the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain is variable and arbitrary.

Preferably, the gain of the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain is variable and discrete.

Preferably, the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain comprises one or more analog amplifiers.

Preferably, the method comprises phase modulating a radio frequency carrier to generate the signal.

Preferably, the method comprises controlling the combined gain of the plurality of amplifiers based on a desired amplitude modulation mode.

Preferably, the method comprises adjusting the power level gain by enabling one of a plurality of fixed gain power amplifiers.

According to yet another aspect of the present invention, there is provided a system for processing a communication signal, comprising:

one or more circuits comprising a plurality of amplifiers, the one or more circuits to:

Preferably, the one or more circuits dynamically adjust settings of the coarse amplitude gain, power level gain, and/or amplitude offset gain.

Preferably, the one or more circuits adaptively adjust settings of the coarse amplitude gain, power level gain, and/or amplitude offset gain.

Preferably, the one or more circuits switch (switching) the gain of one or more of the plurality of amplifiers associated with the coarse amplitude gain between unity gain and an arbitrary fixed gain.

Preferably, the one or more circuits phase modulate a radio frequency carrier to generate the signal.

Preferably, the one or more circuits control the combined gain of the plurality of amplifiers based on a desired amplitude modulation mode.

Preferably, the one or more circuits adjust the power level gain by enabling one of a plurality of fixed gain power amplifiers.

Various advantages, aspects and novel features of the invention, as well as details of an illustrated embodiment thereof, will be more fully described with reference to the following description and drawings.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

fig. 1 is a diagram of an exemplary wireless communication system in accordance with an embodiment of the present invention;

fig. 2 is a constellation diagram of an exemplary 16-QAM constellation in accordance with an embodiment of the present invention;

fig. 3 is an exemplary amplitude diagram of a constellation diagram in accordance with an embodiment of the present invention;

FIG. 4A is a schematic diagram of an exemplary polar amplitude modulation system in accordance with an embodiment of the present invention;

FIG. 4B is a time-amplitude plot of exemplary desired amplitudes (as a function of time) in accordance with one embodiment of the present invention;

fig. 5 is a flow diagram of an exemplary polar amplitude modulation process in accordance with an embodiment of the present invention.

Detailed Description

Some embodiments of the invention relate to methods and systems for polar modulation with discontinuous phase for an RF transmitter with power control. Including amplifying a signal using a plurality of amplifiers such that a combined gain of the plurality of amplifiers includes a coarse amplitude gain, a power level gain, and an amplitude offset gain. The gain of one or more of the plurality of amplifiers is adjusted to set the coarse amplitude gain and the power level gain. The gain of the remaining one or more of the plurality of amplifiers is adjusted to set the amplitude offset gain.

The settings for the coarse amplitude gain, power level gain, and/or amplitude offset gain may be dynamically adjusted and/or adaptively adjusted. The gain of one or more of the plurality of amplifiers associated with the coarse amplitude gain may be switched (switching) between unity gain and an arbitrary fixed gain, and the gain of the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain may be variable and arbitrary or discrete. The remaining one or more of the plurality of amplifiers associated with the amplitude offset gain comprise one or more analog amplifiers. The signal may be generated by phase modulating a radio frequency carrier. The combined gain of the multiple amplifiers may be controlled based on a desired amplitude modulation mode. The power level gain may be adjusted by enabling one of a plurality of fixed gain power amplifiers.

Fig. 1 is a diagram of an exemplary wireless communication system in accordance with an embodiment of the present invention. Referring to fig. 1, there is shown an access point 112b, a computer 110a, a headset 114a, a router 130, the internet 132, and a Web server 134. Computer or host device 110a may include a radio 111a, a short-range radio 111b, a main processor 111c, and a main memory 111 d. The figure also shows a wireless connection between the radio 111a and the access point 112b, a short-range wireless connection between the short-range radio 111b and the headset 114 a.

Generally, computing and communication devices include hardware and software for communicating using a variety of wireless communication standards. For example, the wireless transceiver 111a may comply with a mobile communication standard. It may happen that the radio 111a and the short-range radio 111b are active at the same time. For example, a user of a computer or host device 110a may desire to access the internet 132 in order to consume streaming content from a Web server 134. Accordingly, the user may establish a wireless connection between the computer 110a and the access point 112 b. Once the connection is established, the computer or host device 110a may receive and consume the streaming content from the Web server 134 via the router 130, the access point 112b, and the wireless connection.

The user of computer 110a may also desire to listen to the audio portion of the streaming content on headset 114 a. Accordingly, a user of the computer 110a may establish a short-range wireless connection with the headset 114 a. Once the short-range wireless connection is established, and the appropriate configuration on the computer is initiated, the audio portion of the streaming content can be consumed through the headset 114 a. In the case where such advanced communication systems are integrated or provided within the master device 110a, the generation of Radio Frequencies (RF) may support fast switching enabling support of multiple communication standards and/or advanced broadband systems such as Ultra Wideband (UWB) radios. Other applications of short-range communication may be wireless high definition television (W-HDTV), e.g. from set-top boxes to video displays, which requires high data rates, which may be achieved by very high bandwidth communication techniques, e.g. using UWB and/or 60-GHz communication. High rate data communications by computer 110a (within both radios 111a, short-range radios 111 b) will require high-order physical layer modulation. For example, Quadrature Amplitude Modulation (QAM) may be used, such as a 16-point constellation (16-QAM), a 64-point constellation (64-QAM), or higher order QAMs. Such higher order modulation modes may provide high spectral efficiency when the signal-to-noise ratio between the computer 110a and/or the access point 112b is sufficiently high. The master device 110a may, for example, use polar modulation for the radio 111a and/or the short-range radio 111b according to embodiments of the present invention, as will be described later.

Fig. 2 is a constellation diagram of an exemplary 16-QAM constellation in accordance with an embodiment of the present invention. Referring to fig. 2, real and imaginary axes extending in the complex plane are shown. The amplitude axis is also shown. Each block point represents a given location on the complex plane that can be used for higher order modulation. The block points are called constellation points. In this case, there are 16 regularly arranged constellation points. In various other constellations, there may be any number of constellation points. Each constellation point may be defined by an amplitude and a phase angle from the origin of the recovery plane. In a regularly arranged constellation, such as that shown in fig. 2, a small set of amplitudes and angles is sufficient to represent the entire set of constellation points. For example, all 16 constellation points may be associated with three different amplitudes, e.g., amplitude a, as illustrated by three dashed concentric circles centered on the origin of the complex plane₁、A₂And A₃. In many cases, the number of different amplitudes required is much less than the number of constellation points.

Each circle representing an amplitude level, e.g. amplitude a₁、A₂And A₃It can be projected onto the amplitude axis and marked thereon. For any number of constellation points and any constellation arrangement, the amplitude levels can be projected onto the amplitude axis, as shown in fig. 2.

For example, the modulated transmission signal s (t) may be given by the following relation:

s(t)＝A(t)cos(w_ct+φ(t))＝I(t)cos(w_ct)+Q(t)sin(w_ct)(1)

where A (t) is amplitude and phi (t) is modulated on the carrier cos (w)_ct) angle. A first form of equation (1) can be written in terms of an in-phase component i (t) and a quadrature component q (t). The individual signal components may be given by the following relation:

I(t)＝A(t)cos(φ(t))

Q(t)＝A(t)sin(φ(t))

φ(t)＝tan^-1(Q(t)/I(t))

as shown in fig. 2, the amplitude a (t) and phase phi (t) may be assumed to be a set of discrete values.

Fig. 3 is an exemplary amplitude diagram of a constellation diagram according to an embodiment of the invention. Referring to fig. 3, a constellation amplitude level axis and a quantized constellation amplitude level axis are shown. The constellation amplitude level axis is similar to the amplitude axis shown in fig. 2 and may be derived from, for example, the constellation shown in fig. 2. In the general case, there may be M different amplitude levels for a certain constellation. As shown in fig. 3, the constellation amplitude level axis is marked with a plurality of amplitude levels: a. the₁、A₂、A₃、A₄……A_M-2、A_M-1、A_M。

For a given constellation, as the amplitude level increases, N < M fixed amplitude levels in combination with, for example, analog and continuous amplitude offsets may be more efficiently implemented in some cases. In these cases, the set of amplitudes { A }₁、A₂……A_MCan be mapped to a smaller set of amplitudes { A'₁、A’₂……A’_N}. In addition, each amplitude may be associated with an offset value d_kAssociated, the offset value is for A 'from a given level'_nDefining an amplitude level A_k. Thus, the amplitude can be determined as follows:

A_k＝A′_n+d_k；n∈1，...，N；N＜K

therefore, amplitude A'_nCan be regarded as an amplitude level A_kApproximation of quantization with quantization error d₃. An exemplary quantization process is shown in fig. 3. For example, amplitude level A_kMay be quantized to or associated with the nearest level a 'on the quantized constellation amplitude level axis'_n. For example, amplitude level A₁And A₂Can be quantized to A'₁As shown in fig. 3. Similarly, amplitude level A_M-1And A_MCan be quantized to A'_N，A_M-2Can be quantized to A'_N-1And the like.

For example, amplitude level A₃Can be quantized to a quantized amplitude level A'₂. Amplitude level A₃Also associated with an amplitude offset d₃。

Fig. 4A is a schematic diagram of an exemplary polar amplitude modulation system in accordance with an embodiment of the present invention. Referring to fig. 4A, a polar amplitude modulation system 400 is shown including multipliers 402 and 404, adder 406, amplitude control module 408, a plurality of amplifiers (shown as amplifiers 410, 412, 414, 416, 420, 422, and 424), switching device 426, and coarse amplitude selection module 418. Also shown are the normalized in-phase signal I '(t), the normalized quadrature signal Q' (t), the in-phase carrier cos (w)_ct), orthogonal carrier sin (w)_ct), quantized amplitude A ', quantized constellation amplitude level A'₁、A’₂And A'_NAmplitude deviation d_AAnd transmitting the signals(t)。

The normalized in-phase signal may be determined by the formula I '(t) ═ I (t)/a (t) ═ cos (Φ), and similarly, the normalized quadrature signal may be determined by the formula Q' (t) ═ Q (t)/a (t) ═ sin (Φ). The normalized in-phase signal I' (t) is combined with the in-phase carrier cos (w) in multiplier 402_ct) are multiplied. The normalized quadrature signal Q' (t) is multiplied in multiplier 404 with the quadrature carrier sin (w)_ct) are multiplied. In adder 406, the signals are added to generate an output signal, which is represented by:

I’(t)cos(w_ct)-Q’(t)sin(w_ct)＝cos(w_ct+φ)(2)

in this case, the output signal of the adder 406 is a normalized version of the transmit signal s (t), and in this regard, it can be derived by comparing equation (1) with equation (2).

Coarse amplitude modulation may be achieved by enabling the desired combination of amplifiers, such as amplifiers 410, 412, and 414. The amplitude control module 408 may comprise suitable logic, circuitry, and/or code that may enable generation and quantization of the coarse amplitude level A' (t) and the amplitude offset d_A(as a function of the desired amplitude level) of the corresponding output signal. The quantized amplitude level may be communicatively coupled (communicated) to the coarse amplitude selection module 418. The coarse amplitude selection block 418 may comprise suitable logic, circuitry, and/or code that may enable selection of the gains of the amplifiers 410, 412, and 414 to produce the desired amplitude levels. In one embodiment of the present invention, the gains of amplifiers 410, 412, and 414 may be fixed (toggle), for example, between unity amplification and a suitable gain. In this case, for example, when A'₁＜A’₂＜……＜A’_NAmplitude level A 'after quantization'₁May be determined by setting the gain of amplifier 410 to A'₁And all other amplifiers are kept at unity gain. Gain A'₂For example, by setting the gain of amplifier 410 to A'₁The gain of the amplifier 2 is A'₂-A’₁While other amplifiers maintain unity gain. Similarly, any of N quantized amplitude levelsEach may be achieved by setting a desired amplification gain in a plurality of amplifiers, such as amplifiers 410,412, and 414. In addition, the amplitude control module 408 may also control the gain on the amplifier 416. The amplifier 416 may comprise suitable logic, circuitry, and/or code that may be operable to set the gain dA as a function of the input provided by the amplitude controller 408.

In an embodiment of the invention, the signal power levels are combined into full amplitude, so that a (t) ═ P_k(A’(t)+d_A) That is, at a given time, the amplitude may include a coarse quantized amplitude A' (t) and an amplitude offset d_AWhich may be represented by a factor P_kTo amplify by an amplification factor P_kAssociated with a given transmit power. The transmit power may be selected from a group of power amplifiers. This set of power amplifiers may comprise a set of, for example, K parallel power amplifiers, such as amplifiers 420, 422, and 424 as shown. Amplifiers 420, 422, and 424 may be set to a fixed power setting. This may ensure the efficiency of the amplifier implementation and the desired characteristics such as good linearity. The switching device 426 may comprise suitable logic, circuitry, and/or code that may enable the switching device 426 to directly switch an input signal to a desired power amplifier path.

Fig. 4B is a time-amplitude plot of an exemplary desired amplitude (as a function of time) in accordance with one embodiment of the present invention. Referring to fig. 4B, a horizontal time axis and a vertical amplitude axis are shown. Time increases from left to right and shows a first time interval T₁And a second time interval T₂. Also shown is the time interval T from each₁Associated first power level P₁And a second time interval T₂Associated second power level P₂. And also shows the time interval T₁Associated amplitude level A₁(T₁)、A₂(T₁)、A₃(T₁) And time interval T₂Associated amplitude level A₁(T₂)、A₂(T₂)、A₃(T₂). A (t) shows the desired amplitude sequence over time. Shown in FIG. 4BIn an exemplary embodiment, 3 levels may be mapped into two coarse levels, as given by the following relationship:

A(t)＝P_tA_t where P_t∈{P₁，P₂，...P_K}，A_t∈{A₁＝A′₁-d₁，A₂＝A′₁+d₂，A₃＝A′₂}

e.g. at t₁At the moment, the required amplitude level is represented by amplitude level A₁Multiplied by the appropriate current power level P₁But is given. Similarly, the figure also shows at time t₀、t₂And t₃How to construct the desired amplitude. For example, 3 power levels as shown in fig. 4B may be associated with a 16-QAM system.

Fig. 5 is a flow diagram of an exemplary polar amplitude modulation process in accordance with an embodiment of the present invention. Given the required amplitude level a, the amplitude quantization process according to an embodiment of the invention starts in step 502. In step 503, the desired power level is selected, for example, set accordingly using the switching device 426. In step 504, the amplitude level A' and the amplitude offset d are quantized according to the coarse quantization_ACalculating the required amplitude level: a ═ a' + d_A. Based on quantized amplitude level A' epsilon { A₁、……、A_NWhich may be selected from a set of amplitudes, a set of amplifiers (e.g., amplifiers 410-414) are set to achieve coarse amplitude polar modulation in step 506. At step 508, an amplitude offset is generated using another amplifier, such as amplifier 416. In step 510, an amplitude adjustment cycle is completed, in accordance with an embodiment of the present invention.

In accordance with embodiments of the present invention, methods and systems for polar modulation with discontinuous phase for an RF transmitter with power control functionality. Including amplifying a signal (e.g., the output signal of summer 406) using a plurality of amplifiers (e.g., amplifiers 410, 412, 414) such that the combined gain of the plurality of amplifiers includes a coarse amplitude gain a', a power level gain P, and an amplitude offset gain d_A. The gain a' of one or more of the plurality of amplifiers is adjusted to set the coarse amplitude gain and the power level gain P. Adjusting the gain of one or more of the remaining plurality of amplifiers to set the amplitude offset gain d_A。

The settings for the coarse amplitude gain, the power level gain, and/or the amplitude offset gain may be dynamically adjusted and/or adaptively adjusted, such as by the coarse amplitude selection module 418, a set of amplifiers 420-424, and/or the amplitude control module 408. The gain of one or more of the plurality of amplifiers associated with the coarse amplitude gain may be switched (switching) between unity gain and an arbitrary fixed gain, and the gain of the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain may be variable and arbitrary or discrete, as shown in fig. 4A. The remaining one or more of the plurality of amplifiers associated with the amplitude offset gain, such as amplifier 416, comprises one or more analog amplifiers. The signal may be generated by phase modulating a radio frequency carrier. The combined gain of the multiple amplifiers may be controlled based on the desired amplitude modulation mode, as shown in fig. 4A. The power level gain may be adjusted by enabling a plurality of fixed gain power amplifiers, such as one of the amplifiers 420, 422, 424, as shown in fig. 4A.

Another embodiment of the invention is directed to a machine-readable storage, having stored thereon, a computer program having at least one code executable by a machine, the at least one code when executed by the machine causing the machine to perform the steps described herein for polar modulation using discontinuous phase for an RF transmitter with power control functionality.

Accordingly, the present invention can be realized in hardware, software, or a combination of hardware and software. The present invention can be realized in a centralized fashion in at least one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods of the present invention is suited. A typical combination of hardware and software could be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.

Embodiments of the present invention may be implemented as a board level product (board level product), such as a single chip, an Application Specific Integrated Circuit (ASIC), or as separate components integrated with other portions of the system on a single chip with varying degrees of integration. The degree of integration of the system depends primarily on speed and cost considerations. Modern processors are so diverse that processors currently found on the market can be employed. Additionally, if the processor is available as an ASIC core or logic module, the processors currently found on the market may be part of an ASIC device with firmware for various functions.

The present invention may also be implemented by a computer program product, comprising all the features enabling the implementation of the methods of the invention, when loaded in a computer system. The computer program in this document refers to: any expression, in any programming language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to other languages, codes or symbols; b) reproduced in a different format.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A method for processing a communication signal, comprising:

amplifying a signal using a plurality of amplifiers such that a combined gain of the plurality of amplifiers comprises a coarse amplitude gain, a power level gain, and an amplitude offset gain;

generating and quantizing a coarse amplitude level A' (t) and an amplitude offset d by an amplitude control module_AA corresponding output signal;

combining the signal power levels into full amplitude such that A (t) is P_k(A’(t)+d_A) In the course of feedingAt fixed time, the amplitude includes a coarsely quantized amplitude A' (t) and an amplitude offset d_ABy an amplification factor P_kTo amplify by an amplification factor P_kAssociated with a given transmit power;

2. The method of claim 1, comprising dynamically adjusting settings for the coarse amplitude gain, power level gain, and/or amplitude offset gain.

3. The method according to claim 1, characterized in that the method comprises adaptively adjusting the settings of the coarse amplitude gain, power level gain and/or amplitude offset gain.

4. The method of claim 1, comprising switching the gain of one or more of the plurality of amplifiers associated with the coarse amplitude gain between unity gain and an arbitrary fixed gain.

5. The method of claim 1, wherein the gain of the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain is variable and arbitrary.

6. The method of claim 1, wherein the gain of the remaining one or more of the plurality of amplifiers associated with the amplitude offset gain is variable and discrete.

7. A system for processing a communication signal, comprising:

one or more circuits comprising a plurality of amplifiers and an amplitude control module, the one or more circuits to:

combining the signal power levels into full amplitude such that A (t) is P_k(A’(t)+d_A) At a given time, the amplitude includes a coarse quantized amplitude A' (t) and an amplitude offset d_ABy an amplification factor P_kTo amplify by an amplification factor P_kAssociated with a given transmit power;

8. The system according to claim 7, wherein said one or more circuits dynamically adjust settings of said coarse amplitude gain, power level gain, and/or amplitude offset gain.

9. The system according to claim 7, wherein said one or more circuits adaptively adjust settings for said coarse amplitude gain, power level gain, and/or amplitude offset gain.

10. The system according to claim 7, wherein said one or more circuits switch the gain of one or more of said plurality of amplifiers associated with the coarse amplitude gain between unity gain and an arbitrary fixed gain.