CN110620592A

CN110620592A - Communication device, communication system and method for compensating for non-linearity of transmitter

Info

Publication number: CN110620592A
Application number: CN201910140295.5A
Authority: CN
Inventors: 崔弘旻; 金大暎; 都周铉; 赵莹翼
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2018-06-20
Filing date: 2019-02-26
Publication date: 2019-12-27
Anticipated expiration: 2039-02-26
Also published as: DE102019111124A1; CN110620592B; DE102019111124B4

Abstract

The invention provides a communication device, a communication system and a method for compensating nonlinearity of a transmitter. The communication apparatus includes: a transmitter to provide a first Radio Frequency (RF) signal to a first antenna such that the first antenna outputs a first RF signal; a second antenna for receiving the first RF signal from the first antenna to generate a second RF signal; a receiver for receiving a second RF signal from a second antenna, wherein the receiver generates a feedback signal from the second RF signal; and a controller configured to control the predistortion based on the feedback signal.

Description

Communication device, communication system and method for compensating for non-linearity of transmitter

Technical Field

The present inventive concept relates to wireless communication, and more particularly, to an apparatus and method for compensating for nonlinearity of a transmitter.

Background

The wireless communication device may include a transmitter that provides a Radio Frequency (RF) band signal to an antenna. The transmitter may include components (e.g., filters, power amplifiers, and mixers) that generate RF band signals from baseband signals. In processing the baseband signal, the RF band signal may be distorted due to characteristics of the transistor component. For example, a transmitter may have non-linearity between baseband and RF band signals, thereby distorting the RF band signal and causing interference in wireless communications. In particular, when the frequency (or carrier frequency) of the RF band signal is increased and a plurality of antennas (or antenna arrays) are employed, distortion of the RF band signal due to nonlinearity of the transmitter may be deteriorated. Therefore, the nonlinearity of the transmitter may not be effectively compensated.

Disclosure of Invention

According to an exemplary embodiment of the inventive concept, there is provided a communication apparatus including: a transmitter to provide a first Radio Frequency (RF) signal to a first antenna such that the first antenna outputs the first RF signal; a second antenna for receiving the first RF signal from the first antenna to generate a second RF signal; a receiver to receive the second RF signal from the second antenna, wherein the receiver generates a feedback signal from the second RF signal; and a controller configured to control the predistortion based on the feedback signal.

According to an exemplary embodiment of the inventive concept, there is provided a communication system including: a first apparatus comprising a transmitter to output a first RF signal through a first antenna; and a second apparatus comprising a second antenna for receiving the first RF signal to generate a second RF signal, a receiver for receiving the second RF signal from the second antenna, and a feedback generator for generating a feedback signal from the second RF signal, wherein the first apparatus further comprises a controller configured to control the pre-distortion in response to the feedback signal provided from the second apparatus.

According to an exemplary embodiment of the inventive concept, there is provided a method for compensating for nonlinearity of a transmitter, the method including: generating a baseband signal at a predistorter of a communication device; generating a first RF signal from the baseband signal at a transmitter of the communication device and transmitting the first RF signal through a first antenna of the communication device; receiving the first RF signal through a second antenna of the communication device to generate a second RF signal, and generating a feedback signal from the second RF signal at a receiver of the communication device; and compensating for non-linearity of the transmitter based on the feedback signal.

According to an exemplary embodiment of the inventive concept, there is provided a method for compensating for nonlinearity of a transmitter, the method including: generating a first baseband signal at a predistorter of a first apparatus; generating a first RF signal from the baseband signal at a transmitter of the first apparatus and transmitting the first RF signal through a first antenna of the first apparatus; receiving the first RF signal at a second antenna of a second apparatus to generate a second RF signal; generating a feedback signal at the second apparatus from the second RF signal; providing the feedback signal from the second device to the first device; and compensating for transmitter non-linearity based on the feedback signal.

According to an exemplary embodiment of the inventive concept, there is provided a communication apparatus including: a predistorter configured to generate a first baseband signal; a transmitter configured to generate a first RF signal from the first baseband signal; a first antenna configured to output the first RF signal; a second antenna configured to receive the first radio frequency signal and output a second radio frequency signal corresponding to the first radio frequency signal; a receiver configured to generate a feedback signal from the second RF signal; a controller configured to receive the feedback signal and estimate a nonlinearity of the transmitter based on the feedback signal.

Drawings

The above and other features of the present inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

fig. 1 is a block diagram of a wireless communication system including a wireless communication apparatus according to an exemplary embodiment of the inventive concept;

fig. 2 is a block diagram of an apparatus according to an exemplary embodiment of the inventive concept;

fig. 3 is a block diagram of an apparatus according to an exemplary embodiment of the inventive concept;

fig. 4A and 4B are graphs of data obtained by experiments on an antenna array and a transmitter including four antennas according to an exemplary embodiment of the inventive concept;

fig. 5 is a block diagram of an apparatus according to an exemplary embodiment of the inventive concept;

fig. 6 is a block diagram of an apparatus according to an exemplary embodiment of the inventive concept;

fig. 7 is a block diagram of an apparatus according to an exemplary embodiment of the inventive concept;

fig. 8 is a block diagram of an apparatus according to an exemplary embodiment of the inventive concept;

fig. 9 is a block diagram of a plurality of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept;

fig. 10 is a block diagram of a plurality of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept;

fig. 11 is a block diagram of a plurality of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept;

fig. 12 is a block diagram of a plurality of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept;

fig. 13 is a block diagram of a plurality of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept;

fig. 14 is a flowchart of a method of compensating for nonlinearity of a transmitter according to an exemplary embodiment of the inventive concept;

fig. 15A and 15B are flowcharts of a method of compensating for nonlinearity of a transmitter according to an exemplary embodiment of the inventive concept;

fig. 16 is a flowchart of a method of compensating for nonlinearity of a transmitter according to an exemplary embodiment of the inventive concept;

fig. 17 is a flowchart of operation S40 of fig. 14, according to an exemplary embodiment of the inventive concept; and the number of the first and second groups,

fig. 18 is a block diagram of a communication apparatus according to an exemplary embodiment of the inventive concept.

Detailed Description

Fig. 1 is a block diagram of a wireless communication system including a wireless communication device 10 according to an exemplary embodiment of the inventive concept. The wireless communication system 10 may be, but is not limited to, a wireless communication system using a cellular network (e.g., a 5 th generation (5G) wireless system, a Long Term Evolution (LTE) system, an LTE-advanced system, a Code Division Multiple Access (CDMA) system, or a global system for mobile communications (GSM) system), a Wireless Local Area Network (WLAN), wireless fidelity (WiFi), bluetooth, or any other wireless communication system. In the following, the wireless communication system 10 will be described mainly with reference to a wireless communication system using a cellular network, but it should be understood that the following exemplary embodiments are not limited thereto.

The first apparatus 100 and the second apparatus 1 may each be any type of apparatus capable of transmitting and receiving signals by wireless communication. The first apparatus 100 and the second apparatus 1 may each be referred to as a communication apparatus or a wireless communication apparatus. In an exemplary embodiment of the inventive concept, the first device 100 may be a base station,

the second apparatus 1 may be a user equipment. In an exemplary embodiment of the inventive concept, the first apparatus 100 may be a user equipment and the second apparatus 1 may be a base station. A base station may be a fixed station configured to communicate with user equipment and/or other base stations. The base stations may communicate with user equipment and/or other base stations and exchange data and control information. For example, a base station may be referred to as a node B, evolved node B (enb), sector, site, Base Transceiver System (BTS), Access Point (AP), relay node, Remote Radio Head (RRH), Radio Unit (RU), or small cell (smallcell). The user equipment may be fixed or have mobility, and refers to various apparatuses capable of communicating with the base station and transceiving data and/or control information. For example, the user equipment may be a terminal equipment, a Mobile Station (MS), a Mobile Terminal (MT), a User Terminal (UT), a Subscriber Station (SS), a wireless device, or a handheld device. A wireless communication network between a user equipment and a base station may support multiple users communicating with each other by sharing available network resources. For example, in a wireless communication network, information may be transmitted using various multiple access methods, such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), single carrier frequency division multiple access (SC-FDMA), OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA.

Referring to fig. 1, the first device 100 may include a data processor 110, a transmitter 130, and an antenna 150. The data processor 110 may generate a first baseband signal BB1 and provide a first baseband signal BB1 to the transmitter 130. In an exemplary embodiment of the inventive concept, the baseband signal may be a training signal. The transmitter 130 may process the first baseband signal BB1, generate a first Radio Frequency (RF) signal RF1, and provide the first RF signal RF1 to the antenna 150. As used herein, the antenna 150 configured to transmit the first RF signal RF1 may be referred to as a first antenna. The second device 1 may receive the first signal 12 from the first device 100. The second device 1 may comprise an antenna and transmits the second signal 14 to the first device 100 through the antenna. The first apparatus 100 may further comprise a receiver configured to receive the second signal 14. In an exemplary embodiment of the inventive concept, the transmitter 130 and the receiver may be implemented as transceivers in one block.

The transmitter 130 may comprise means configured to process the first baseband signal BB 1. For example, as shown in fig. 1, transmitter 130 may include a mixer 132, a filter 134, a phase shifter 136, and a power amplifier 138. In an exemplary embodiment of the inventive concept, the transmitter 130 may include only some of the components of fig. 1. In exemplary embodiments of the inventive concept, the transmitter 130 may further include a non-existing transmitter

Additional components are shown in fig. 1. In exemplary embodiments of the inventive concept, the mixer 132, the filter 134, the phase shifter 136, and the power amplifier 138 may process the first baseband signal BB1 in a different order than shown in fig. 1.

The transmitter 130 may have non-linearity due to the characteristics of its components. For example, the power amplifier 138 may have a non-linear gain, and the non-linear gain of the power amplifier 138 may result in non-linearity of the transmitter 130. Predistortion may be used to compensate for non-linearity of transmitter 130. Predistortion may refer to a method of predistorting the input of transmitter 130 (e.g., first baseband signal BB1) based on a nonlinearity that is opposite to the nonlinearity of transmitter 130. Due to the pre-distortion, non-linearities of the transmitter 130 may be compensated and the desired first RF signal RF1 may be provided to the antenna 150. As described above, the non-linearity of the transmitter 130 may be determined by a number of components included in the transmitter 130. When the emitter 130 is an Integrated Circuit (IC), the nonlinearity of the emitter 130 may change due to process, voltage, and temperature (PVT) variations. Accordingly, in order to accurately compensate for the nonlinearity of the transmitter 130, predistortion may be performed based on feedback generated from the output of the transmitter 130.

To generate feedback from the output of the transmitter 130, a unit configured to obtain the output of the transmitter 130 (e.g., a coupler, port, or test point) may be positioned between the transmitter 130 and the antenna 150. However, the unit may be sensitive to short wave signals (e.g., millimeter waves). Therefore, by distorting the first RF signal RF1, the reliability of the wireless transmission may be reduced. As described below with reference to fig. 3, the first apparatus 100 may include a plurality of antennas or a plurality of first antennas to implement beamforming or Multiple Input Multiple Output (MIMO). The transmitter 130 may include components (e.g., a plurality of phase shifters and a plurality of power amplifiers) respectively corresponding to the plurality of antennas. Obtaining feedback from all of the multiple paths corresponding to the multiple antennas, nor individually pre-distorting each of the multiple paths, is effectively accomplished. However, as described below, according to an exemplary embodiment of the inventive concept, feedback may be generated based on a signal output by the antenna 150 in response to the first RF signal RF1 to easily and accurately perform predistortion.

The data processor 110 may include a predistorter 112, and the predistorter 112 may predistort the transmit signal TXS and generate a first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the transmission signal TXS may be a digital signal and the predistorter 112 may be a Digital Predistorter (DPD) which may generate a distorted digital signal from the transmission signal TXS. The data processor 110 may comprise a digital-to-analog converter (DAC) which may convert the digital signal output by the predistorter 112 and output a first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the transmission signal TXS may be an analog signal and the predistorter 112 may be an analog predistorter. Herein, it is assumed that the predistorter 112 is a digital predistorter, and for the sake of brevity, a description of a DAC included in the data processor 110 is omitted, and the predistorter 112 may generate the first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the predistorter 112 used as a digital predistorter may include at least one of a hardware block designed by logic synthesis (logic synthesis) and a software block including a series of instructions. In an exemplary embodiment of the inventive concept, the data processor 110 may be a modem.

The data processor 110 may receive a feedback FB based on the output of the transmitter 130 and perform predistortion based on the feedback FB. The feedback FB may be generated based on the first RF signal RF1 transmitted through the antenna 150. In an exemplary embodiment of the inventive concept, as described below with reference to fig. 2 to 8, the feedback FB may be generated based on an RF signal received through another antenna (e.g., 290 in fig. 2) included in the first apparatus 100. In an exemplary embodiment of the inventive concept, the feedback FB may be generated by an apparatus (e.g., 90 in fig. 9) other than the first apparatus 100, as described below with reference to fig. 9 to 12. Accordingly, the nonlinearity of the transmitter 130 can be accurately compensated and the reliability of wireless communication can be improved. The nonlinearity of the transmitter 130 can be accurately and effectively compensated even in wireless communication using an antenna array including a plurality of antennas. Further, a component configured to provide feedback for predistortion between the transmitter 130 and the antenna 150 may be omitted, so that distortion caused by feedback may be removed from wireless communication using short waves.

Fig. 2 is a block diagram of an apparatus 200 according to an exemplary embodiment of the inventive concept. For example, fig. 2 shows an apparatus 200 configured to generate feedback for predistortion based on an RF signal received through an antenna included therein. The second baseband signal BB2 of fig. 2 may be used as the feedback FB of fig. 1. As shown in fig. 2, the apparatus 200 may include a data processor 210, a transmitter 230, a first antenna 250, a receiver 270, and a second antenna 290.

As described above with reference to fig. 1, the data processor 210 may provide the first baseband signal BB1 to the transmitter 230, and the transmitter 230 may generate the first RF signal RF1 from the first baseband signal BB1 and provide the first RF signal RF1 to the first antenna 250. The receiver 270 may receive the second RF signal RF2 caused by the first RF signal RF1 through the second antenna 290, generate a second baseband signal BB2 from the second RF signal RF2, and provide the second baseband signal BB2 to the data processor 210. In an exemplary embodiment of the inventive concept, the first antenna 250 may be a transmitting antenna and the second antenna 290 may be a receiving antenna of the same wireless communication system (e.g., 5G, LTE, etc.). In an exemplary embodiment of the inventive concept, the first antenna 250 may support a wireless communication system using a cellular network, and the second antenna 290 may support a different wireless communication system such as a WLAN. In an exemplary embodiment of the inventive concept, the second antenna 290 may be a dedicated reception antenna for predistortion.

The data processor 210 may include a predistorter 212 and a controller 214. Predistorter 212 may distort transmit signal TXS and generate first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the predistorter 212 may include at least one look-up table, and generate the first baseband signal BB1 based on an output of the at least one look-up table corresponding to the transmission signal TXS. In exemplary embodiments of the inventive concept, the predistorter 212 may comprise at least one calculator configured to calculate a polynomial comprising the transmission signal TXS and at least one coefficient, and the predistorter 212 may generate the first baseband signal BB1 based on an output of the at least one calculator. The predistorter 212 may perform predistortion using a variety of methods. For example, the predistorter 212 may perform predistortion according to indirect learning, which is described in "a new voltage predistorter based on the indirect learning architecture" published by c.eun and e.j.powers in IEEE trans.signaling processing 1997, volume 45, 223-. Predistorter 212 may also perform predistortion according to the techniques described in "a Robust digital baseband Predistorter Using Memory cryptography" published by ieee transactions on Communications, 2004, volume 52, month 1, volume 52, by d.lei, Zhou and Tong. The entire disclosures of these articles are incorporated herein by reference. When the samples of the transmission signal TXS (input to predistorter 212) are x (N) and the samples of the first baseband signal BB1 (output of predistorter 212) are y (N) (1 ≦ N ≦ N, N being a positive integer), predistorter 212 may be modeled by a polynomial as in equation 1:

wherein p represents the order of the polynomial. When N samples are provided, predistorter 212 may be modeled by:

a of equation 2 may be calculated using a least squares method, as in equation 3:

the controller 214 may control the predistorter 212 based on a second baseband signal BB2 received from the receiver 270. In an exemplary embodiment of the inventive concept, the controller 214 may control the predistorter 212 to generate a predefined first baseband signal BB1 regardless of the transmission signal TXS and estimate the nonlinearity of the transmitter 230 based on a second baseband signal BB2 corresponding to the first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the controller 214 may receive the first baseband signal BB1 and estimate the nonlinearity of the transmitter 230 based on the first baseband signal BB1 and the second baseband signal BB 2. Although fig. 3 and 5 to 8 show the case where the controller of the data processor receives only the second baseband signal BB2, it should be noted that the controller may receive the first baseband signal BB1 (as indicated by the dashed line in fig. 2). Although fig. 3 shows the case where the controller 314 receives the second baseband signal BB2 directly, the data processor 310 may comprise an analog-to-digital converter (ADC). In this case, when the second baseband signal BB2 in analog form is transmitted from the receiver 370, the ADC may convert the second baseband signal BB2 into a digital signal so that the controller 314 may receive the digital signal.

In the predistortion setting mode, the controller 214 may set the predistortion of the predistorter 212 based on the second baseband signal BB 2. In an exemplary embodiment of the inventive concept, the controller 214 may SET at least one parameter for defining an operation of the predistorter 212 based on the setting signal SET, and the predistorter 212 may perform predistortion based on the at least one parameter. For example, the controller 214 may obtain equation 3 based on the second baseband signal BB2And is based onThe SET signal SET is generated. When the controller 214 finishes setting the predistortion of the predistorter 212, the controller 214 may leave the predistortion setting mode. In the wireless communication mode, the predistorter 212 may distort the transmit signal TXS according to the settings of the controller 214 and generate a first baseband signal BB 1.

Fig. 3 is a block diagram of an apparatus 300 according to an exemplary embodiment of the inventive concept. For example, fig. 3 shows an apparatus 300 configured to transmit a signal through an antenna array. Similar to fig. 2, the second baseband signal BB2 of fig. 3 may be used as the feedback FB of fig. 1. As shown in fig. 3, the apparatus 300 may include a data processor 310, a transmitter 330, a plurality of first antennas 350_1 to 350_ m, a receiver 370, and a second antenna 390(m is an integer greater than 1).

The data processor 310 may provide the first baseband signal BB1 to the transmitter 330, and the transmitter 330 may generate a plurality of first RF signals RF11 to RF1m corresponding to the plurality of first antennas 350_1 to 350 — m in response to the first baseband signal BB 1. For example, the transmitter 330 may include m power amplifiers corresponding to the plurality of first RF signals RF11 through RF1 m. The plurality of first antennas 350_1 to 350_ m may be referred to as an antenna array and used for beamforming or MIMO. As shown in fig. 3, the compensation for the non-linearity of the transmitter 330 configured to generate the plurality of first RF signals RF11 through RF1m may include: instead of compensating each of the m paths corresponding to the plurality of first RF signals RF11 to RF1, the first baseband signal BB1 distorted using one predistorter 312 is generated. As described below with reference to fig. 4A and 4B, experimental data indicate that the use of a single predistorter 312 is effective in compensating for non-linearities of the transmitter 330 for the antenna array.

The receiver 370 may receive a second RF signal RF2 from the second antenna 390, the second RF signal RF2 being generated based on at least one of the plurality of first RF signals RF11 through RF1 m. The receiver 370 may generate a second baseband signal BB2 from the second RF signal RF2 and provide the second baseband signal BB2 to the data processor 310. The controller 314 of the data processor 310 may generate a SET signal SET based on the second baseband signal BB2 and SET at least one parameter of the predistorter 312 via the SET signal SET. The predistorter 312 may distort the transmit signal TXS based on at least one parameter and generate a first baseband signal BB 1.

Fig. 4A and 4B are graphs of data obtained by experiments on an antenna array and a transmitter including four antennas P0, P1, P2, and P3 according to an exemplary embodiment of the inventive concept. For example, fig. 4A shows the amplitude ratio between the input (e.g., BB1 in fig. 3) and the feedback (e.g., BB2 in fig. 3) of the transmitter, and fig. 4B shows the amplitude ratio between the input (e.g., TXS in fig. 3) and the output (e.g., BB1 in fig. 3) of the predistorter set based on the feedback. Hereinafter, fig. 4A and 4B will be described with reference to fig. 3.

Referring to fig. 4A, signals fed back from four antennas P0, P1, P2, and P3, respectively, may provide different amplitude ratios due to different antenna gains of the four antennas P0, P1, P2, and P3. However, referring to fig. 4B, predistortion characteristics obtained in consideration of a difference between antenna gains may be approximately equal. In other words, the plurality of first RF signals RF 11-RF 1m generated by the transmitter 330 for the antenna array may have approximately the same non-linearity as the transmitter 330. Accordingly, as described above with reference to fig. 3, non-linearities of the transmitter 330 configured to generate the first RF signals RF11 through RF1m may be effectively compensated for by using one predistorter 312.

Fig. 5 is a block diagram of an apparatus 500 according to an exemplary embodiment of the inventive concept. For example, fig. 5 shows an apparatus 500 configured to transmit a signal through an antenna array configured to form a beam. Similar to fig. 2, the second baseband signal BB2 of fig. 5 may be used as the feedback FB of fig. 1. Such as

As shown in fig. 5, the apparatus 500 may include a data processor 510, a transmitter 530, a plurality of first antennas 550_1 to 550_ m, a receiver 570, and a second antenna 590.

The data processor 510 may provide the first baseband signal BB1 to the transmitter 530, and the transmitter 530 may generate a plurality of first RF signals RF11 to RF1m corresponding to the plurality of first antennas 550_1 to 550_ m in response to the first baseband signal BB 1. The transmitter 530 may include a plurality of phase shifters PS1 to PSm and a plurality of power amplifiers PA1 to PAm corresponding to the plurality of first RF signals RF11 to RF1 m. The plurality of first RF signals RF11 through RF1m may have phases shifted by the plurality of phase shifters PS1 through PSm. Accordingly, the plurality of first antennas 550_1 to 550_ m may form the beam 4.

In the predistortion setting mode, the controller 514 may control the plurality of phase shifters PS1 through PSm such that the beam 4 formed by the plurality of first antennas 550_1 through 550_ m is directed toward the second antenna 590. For example, as shown in fig. 5, the controller 514 may provide a first control signal C1 for controlling the plurality of phase shifters PS1 through PSm to the transmitter 530. In the ith RF signal (1 ≦ i ≦ m), the gain of the ith antenna is assumed to be G_iThe phase shift caused by the ith phase shifter is shifter_iA path including an internal path of the transmitter 530, a path between the transmitter 530 and the plurality of first antennas 550_1 to 550_ m, a wireless channel, and the likeThe induced phase shift is path_iThe non-linear function of the ith power amplifier is PA_iThe nonlinear function caused by predistorter 512 is PD. When ignoring the effect of the second antenna 590 and the receiver 570, the second baseband signal BB2 may be expressed as equation 4:

in an exemplary embodiment of the inventive concept, (shifter) in equation 4 for all values of i (1 ≦ i ≦ m) when the controller 514 controls the plurality of phase shifters PS1 through PSm to form the beam 4 toward the second antenna 590_i+path_i) May be approximately equal. Therefore, in the predistortion setting mode, the controller 514 may SET the predistortion of the predistorter 512 by the setting signal SET based on the second baseband signal BB2, the second baseband signal BB2 being generated from the second RF signal RF2 caused by simultaneously transmitting the plurality of first RF signals RF11 to RF1 m.

Fig. 6 is a block diagram of an apparatus 600 according to an exemplary embodiment of the inventive concept. For example, fig. 6 shows an apparatus 600 configured to sequentially transmit a plurality of first RF signals RF11 through RF1m in a predistortion setting mode. Similar to fig. 2, the second baseband signal BB2 of fig. 6 may be used as the feedback FB of fig. 1. As shown in fig. 6, the apparatus 600 may include a data processor 610, a transmitter 630, a plurality of switches 640_1 to 640_ m, a plurality of first antennas 650_1 to 650_ m, a receiver 670, and a second antenna 690.

The data processor 610 may provide the first baseband signal BB1 to the transmitter 630, and the transmitter 630 may generate a plurality of first RF signals RF11 to RF1m corresponding to the plurality of first antennas 650_1 to 650_ m from the first baseband signal BB 1. The plurality of switches 640_1 to 640_ m may allow or prevent the plurality of first RF signals RF11 to RF1m from being transmitted to the plurality of first antennas 650_1 to 650_ m, respectively, by control of the controller 614. In an exemplary embodiment of the inventive concept, the controller 614 may control the plurality of switches 640_1 to 640_ m to sequentially transmit the plurality of first RF signals RF11 to RF1m to the plurality of first antennas 650_1 to 650_ m.

In an exemplary embodiment of the inventive concept, a plurality of switches 640_1 to 640_ m may be included in the transmitter 630, different from that shown in fig. 6. In an exemplary embodiment of the inventive concept, the controller 614 may sequentially transmit the plurality of first RF signals RF11 through RF1m to the plurality of first antennas 650_1 through 650_ m by sequentially powering on and off a plurality of components (e.g., a plurality of power amplifiers) included in the transmitter 630.

The receiver 670 may repeatedly receive the second RF signal RF2 corresponding to each of the plurality of first RF signals RF11 through RF1m and sequentially generate a plurality of second baseband signals BB 2. In the predistortion setting mode, the controller 614 may collect the plurality of second baseband signals BB2 and set the predistortion of the predistorter 612 based on the plurality of second baseband signals BB 2. In an exemplary embodiment of the inventive concept, the controller 614 may set the predistortion of the predistorter 612 based on an average value of the plurality of second baseband signals BB 2.

Fig. 7 is a block diagram of an apparatus 700 according to an exemplary embodiment of the inventive concept. For example, fig. 7 shows an apparatus 700 configured to transmit and receive signals over the same antenna array. Similar to the one shown in figure 2, the first,

the second baseband signal BB2 of fig. 7 may be used as the feedback FB of fig. 1. As shown in fig. 7, the apparatus 700 may include a data processor 710, a transmitter 730, a plurality of switches 740_1 to 740_ m, a plurality of antennas 750_1 to 750_ m, and a receiver 770.

The data processor 710 may provide the first baseband signal BB1 to the transmitter 730, and the transmitter may generate at least one first RF signal RF1 from the first baseband signal BB 1. The plurality of switches 740_1 to 740_ m may connect the antenna array (e.g., the plurality of antennas 750_1 to 750_ m) to the transmitter 730 or the receiver 770 according to a transmission mode or a reception mode.

The controller 714 of the data processor 710 may control the plurality of switches 740_1 to 740_ m such that at least one first RF signal RF1 may be transmitted through at least one of the plurality of antennas 750_1 to 750_ m included in the antenna array and a second RF signal RF2 caused by the at least one first RF signal RF1 may be received through at least one of the plurality of antennas 750_1 to 750_ m. For example, as shown in fig. 7, the controller 714 may control the first switch 740_1 such that the first RF signal RF1 may be transmitted through the first antenna 750_ 1. Accordingly, due to the mutual coupling between the first antenna 750_1 and the second antenna 750_2, a signal caused by the first RF signal RF1 may be induced on the second antenna 750_ 2. As shown in fig. 7, the controller 714 may control the second switch 740_2 such that the second RF signal RF2 caused by the first RF signal RF1 may be received through the second antenna 750_ 2.

The receiver 770 may generate a second baseband signal BB2 from the second RF signal RF2 and provide the second baseband signal BB2 to the data processor 710. In the predistortion setting mode, the controller 714 may set the predistortion of the predistorter 712 of the data processor 710 based on the second baseband signal BB 2.

Fig. 8 is a block diagram of an apparatus 800 according to an exemplary embodiment of the inventive concept. For example, fig. 8 shows an apparatus 800 that includes an isolator 820 positioned between a first antenna 850 and a second antenna 890. Similar to fig. 2, the second baseband signal BB2 of fig. 8 may be used as the feedback FB of fig. 1. As shown in fig. 8, the apparatus 800 may include a data processor 810, a transmitter 830, a first antenna 850, a receiver 870, a second antenna 890, and an isolator 820.

The data processor 810 may provide the first baseband signal BB1 to the transmitter 830, and the transmitter 830 may generate the first RF signal RF1 from the first baseband signal BB1 and provide the first RF signal RF1 to the first antenna 850. In the predistortion setting mode, the receiver 870 may receive the second RF signal RF2 caused by the first RF signal RF1 through the second antenna 890, generate the second baseband signal BB2, and provide the second baseband signal BB2 to the data processor 810. In the wireless communication mode, the first antenna 850 may function as a transmitting antenna and the second antenna 890 may function as a receiving antenna.

The isolator 820 may provide variable coupling (or interference) between the first antenna 850 and the second antenna 890 through control of the controller 814 of the data processor 810. For example, in the predistortion setting mode, the controller 814 may provide the second control signal C2 to the isolator 820 such that the isolator 820 may provide a relatively high coupling between the first antenna 850 and the second antenna 890 such that the second antenna 890 is able to receive the second RF signal RF2 caused by the first RF signal RF 1. Further, in the wireless communication mode, the controller 814 may provide the second control signal C2 to the isolator 820 such that the isolator 820 may provide a relatively low coupling between the first antenna 850 and the second antenna 890 to reduce the effect of signals transmitted by the first antenna 850 and received by the second antenna 890. In an exemplary embodiment of the inventive concept, the isolator 820 may include a material that changes a phase in response to the second control signal C2. In an exemplary embodiment of the inventive concept, the isolator 820 may include a capacitor having a variable capacitance in response to the second control signal C2. In an exemplary embodiment of the inventive concept, the isolator 820 may include a shield (shield) including a conductor and moving in response to the second control signal C2.

Fig. 9 is a block diagram of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept. For example, fig. 9 shows an example where a first apparatus 900 receives feedback FB from a second apparatus 90 located outside the first apparatus 900 to compensate for non-linearities of a transmitter 930 included in the first apparatus 900. In an exemplary embodiment of the inventive concept, the type of the second apparatus 90 may be the same as the type of the first apparatus 900. In an exemplary embodiment of the inventive concept, the second apparatus 90 may be a dedicated apparatus (e.g., a measurement device) configured to provide the feedback FB to the first apparatus 900.

Referring to fig. 9, the first apparatus 900 may include a data processor 910, a transmitter 930, and a first antenna 950. The data processor 910 may provide the first baseband signal BB1 to the transmitter 930, and the transmitter 930 may generate the first RF signal RF1 from the first baseband signal BB 1. The first RF signal RF1 may be transmitted through the first antenna 950. Although the first apparatus 900 is illustrated in fig. 9 as including one first antenna 950, in an exemplary embodiment of the inventive concept, the first apparatus 900 may transmit the first RF signal RF1 through an antenna array including a plurality of antennas.

The second device 90 may include a second antenna 92, a receiver 94, and a feedback generator 96. The receiver 94 may receive the second RF signal RF2 caused by the first RF signal RF1 through the second antenna 92 and generate a second baseband signal BB2 from the second RF signal RF 2. The feedback generator 96 may generate a feedback FB based on the second baseband signal BB2 and provide the feedback FB to the first apparatus 900. As described below, the feedback FB may be provided to the data processor 910 included in the first apparatus 900 in various ways.

The data processor 910 of the first apparatus 900 may include a predistorter 912 and a controller 914. In the predistortion setting mode, the controller 914 may generate a setting signal SET for setting the predistortion of the predistorter 912 based on the feedback FB or based on the feedback FB and the first baseband signal BB 1. The predistorter 912 may distort the transmission signal TXS based on predistortion SET by the setting signal SET and generate a first baseband signal BB 1. Although fig. 11 to 13 show the case where the controller of the data processor receives only the feedback FB, it should be noted that the controller may receive the first baseband signal BB 1.

Fig. 10 is a block diagram of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept. For example, fig. 10 shows a first apparatus 900a including an interface circuit 980 configured to receive feedback and a second apparatus 90a configured to provide feedback.

Referring to fig. 10, the first apparatus 900a may include a data processor 910a, a transmitter 930a, a first antenna 950a, and an interface circuit 980. The transmitter 930a may generate a first RF signal RF1 from the first baseband signal BB1 received from the data processor 910a and provide the first RF signal RF1 to the first antenna 950 a. The second device 90a may include a second antenna 92a, a receiver 94a, and a feedback generator 96 a. The receiver 94a may generate a second baseband signal BB2 from the second RF signal RF2 and provide the second baseband signal BB2 to the feedback generator 96 a.

The second device 90a may provide feedback to the first device 900a over a communication channel that is different from the wireless communication channel used to transmit the first RF signal RF 1. For example, the second device 90a may transmit the encoded signal ENC as feedback through a wired communication channel (e.g., Universal Serial Bus (USB) and Peripheral Component Interconnect (PCI)). Alternatively, the second device 90a may transmit the encoded signal ENC as feedback over a wireless communication channel (e.g., WiFi and bluetooth). The interface circuit 980 of the first device 900a may receive the encoded signal ENC from the second device 90a according to a protocol, decode the encoded signal ENC according to the protocol, and provide the decoded signal DEC to the data processor 910 a. In the predistortion setting mode, the controller 914a of the data processor 910a may receive the decoded signal DEC as feedback, generate the setting signal SET based on the decoded signal DEC, and SET the predistortion of the predistorter 912a by the setting signal SET. In the wireless communication mode, predistorter 912a of data processor 910a may distort transmit signal TXS based on the set predistortion and generate first baseband signal BB 1.

Fig. 11 is a block diagram of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept. For example, fig. 11 shows an example of transmitting the first RF signal RF1 and the feedback over the same wireless channel.

Referring to fig. 11, the first device 900b may include a data processor 910b, a transceiver 930b, and a first antenna 950 b. The transceiver 930b may generate a first RF signal RF1 from the first baseband signal BB1 received from the data processor 910b and transmit the first RF signal RF1 to the second device 90b through the first antenna 950 b.

The second device 90b may include a second antenna 92b, a transceiver 94b, and a feedback generator 96 b. The second antenna 92b may receive the first RF signal RF1, and the transceiver 94b may generate the second baseband signal BB2 and provide the second baseband signal BB2 to the feedback generator 96 b. The feedback generator 96b may generate the first feedback signal FB1 based on the second baseband signal BB 2. As shown in fig. 11, the feedback generator 96b may include a modulator 96b _ 1. To provide feedback over the same wireless channel as used to transmit the first RF signal RF1, the modulator 96b _1 may modulate the second baseband signal BB2 or a signal generated from the second baseband signal BB2 and generate the first feedback signal FB 1. The transceiver 94b may generate a second feedback signal FB2 (which is an RF band signal) from the first feedback signal FB1 (which is a baseband signal) and provide the second feedback signal FB2 to the first apparatus 900b through the second antenna 92 b. The transceiver 930b of the first apparatus 900b may receive the second feedback signal FB2 through the first antenna 950b and generate a third feedback signal FB3 (which is a baseband signal) from the second feedback signal FB2 (which is an RF band signal). The third feedback signal FB3 may be provided to the data processor 910 b.

Data processor 910b may include a predistorter 912b, a controller 914b, and a demodulator 916. The demodulator 916 may demodulate the third feedback signal FB3 using a demodulation scheme corresponding to the modulation scheme of the modulator 96b _1 of the second apparatus 90b, generate a demodulated signal DM, and provide the demodulated signal DM to the controller 914 b. In the predistortion setting mode, the controller 914b may generate the setting signal SET based on the demodulation signal DM. In the wireless communication mode, the predistorter 912b may distort the transmission signal TXS according to the set predistortion and generate a first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the first apparatus 900b and the second apparatus 90b may be the same type of apparatus, for example, the first apparatus 900b and the second apparatus 90b may be terminals of the same wireless communication system.

Fig. 12 is a block diagram of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept. For example, fig. 12 shows a first apparatus 900c configured to transmit a signal through an antenna array (configured to form a beam 11), and a second apparatus 90c configured to provide feedback FB to the first apparatus 900 c.

As described above with reference to fig. 5, the first device 900c may form a beam 11 towards the second antenna 92c of the second device 90 c. For example, the controller 914C of the data processor 910C may control the plurality of phase shifters PS1 to PSm of the transmitter 930C by the third control signal C3. The controller 914C of the data processor 910C may generate the third control signal C3 such that the plurality of first RF signals RF11 to RF1m output through the plurality of power amplifiers PA1 to PAm may form the beam 11.

The second apparatus 90c may receive the beam 11 through the second antenna 92c and the feedback generator 96c may provide the feedback FB to the first apparatus 900c based on the second baseband signal BB2 generated by the receiver 94c from the second RF signal RF 2. For example, in an exemplary embodiment of the inventive concept, the feedback FB may be provided to the first apparatus 900c through other communication channels as described above with reference to fig. 10. In an exemplary embodiment of the inventive concept, the feedback FB may be provided through the same wireless channel as the beam 11, as described above with reference to fig. 11. In the predistortion setting mode, the controller 914c of the first apparatus 900c may generate the setting signal SET based on the feedback FB. In the wireless communication mode, the predistorter 912c may distort the transmission signal TXS based on the set predistortion and generate a first baseband signal BB 1.

Fig. 13 is a block diagram of apparatuses configured to communicate with each other according to an exemplary embodiment of the inventive concept. For example, fig. 13 shows a first apparatus 900d configured to sequentially transmit a plurality of first RF signals RF11 through RF1m in a predistortion setting mode, and a second apparatus 90d configured to provide a feedback FB to the first apparatus 900 d.

The first apparatus 900d may sequentially transmit the plurality of first RF signals RF11 through RF1m generated by the transmitter 930d as described above with reference to fig. 6. For example, the first apparatus 900d may include a plurality of switches 940d _1 to 940d _ m. In the predistortion setting mode, the controller 914d of the data processor 910d may sequentially turn on and/or off the plurality of switches 940d _1 to 940d _ m. The second device 90d may sequentially receive the plurality of first RF signals RF11 through RF1m through the second antenna 92 d. A plurality of first RF signals RF11 through RF1m may be output through the plurality of first antennas 950d _1 through 950d _ m. The receiver 94d of the second device 90d may repeatedly generate the second baseband signal BB2 from the repeatedly received second RF signal RF 2.

The feedback generator 96d of the second apparatus 90d may provide the feedback FB to the first apparatus 900d based on the repeatedly generated second baseband signal BB2 (i.e., the plurality of second baseband signals BB 2). In an exemplary embodiment of the inventive concept, the feedback generator 96d may provide the feedback FB to the first apparatus 900d each time the second baseband signal BB2 is received. In an exemplary embodiment of the inventive concept, the feedback generator 96d may provide one feedback FB to the first device 900d based on the plurality of second baseband signals BB 2. In the predistortion setting mode, the controller 914d of the first apparatus 900d may generate the setting signal SET based on the feedback FB. In the wireless communication mode, the predistorter 912d may distort the transmission signal TXS based on the set predistortion and generate a first baseband signal BB 1.

Fig. 14 is a method of compensating for nonlinearity of a transmitter according to an exemplary embodiment of the inventive concept. For example, the method of fig. 14 may be performed by the first apparatus 100 of fig. 1, which will be described with reference to fig. 1.

In operation S20, an operation of generating the first baseband signal BB1 may be performed. For example, the predistorter 112 of the data processor may generate a first baseband signal BB 1. In an exemplary embodiment of the inventive concept, the first baseband signal BB1 generated in the predistortion setting mode may be a predefined signal, or in an exemplary embodiment of the inventive concept, the first baseband signal BB1 generated in the predistortion setting mode may be a signal generated from the transmission signal TXS.

In operation S40, an operation of transmitting the first RF signal RF1 may be performed. For example, the transmitter 130 may generate a first RF signal RF1 from the first baseband signal BB1 and transmit the first RF signal RF1 through the antenna 150.

In operation S60, an operation of obtaining the feedback FB based on the first RF signal RF1 may be performed. Accordingly, the feedback FB can be generated based on the signal transmitted through the antenna 150, thereby easily and accurately compensating for the distortion.

In operation S80, an operation of compensating for the nonlinearity of the transmitter 130 based on the feedback FB may be performed. For example, in the predistortion setting mode, the predistortion of the predistorter 112 may be set based on the feedback FB. In the wireless communication mode, the predistorter 112 may perform the set predistortion and generate a first baseband signal BB 1.

Fig. 15A and 15B are flowcharts of a method of compensating for nonlinearity of a transmitter according to an exemplary embodiment of the inventive concept. For example, fig. 15A illustrates a method of generating feedback for predistortion based on an RF signal received through an antenna included in a device having a transmitter. Fig. 15B illustrates a method of receiving feedback from a device external to the device including the transmitter. For example, the method of fig. 15A may be performed by apparatus 200 of fig. 2, and the method of fig. 15B may be performed by apparatus 900 of fig. 9. Hereinafter, fig. 15A will be described with reference to fig. 2, and fig. 15B will be described with reference to fig. 9. Further, the same description as fig. 14 may be omitted.

Referring to fig. 15A, in operation S20a, an operation of generating a first baseband signal BB1 may be performed. Next, in operation S40a, an operation of transmitting the first RF signal RF1 through the first antenna 250 may be performed.

In operation S60a, an operation of obtaining feedback may be performed. As shown in fig. 15A, operation S60a may include operation S62a and operation S64 a. In operation S62a, an operation of obtaining a second RF signal RF2 through the second antenna 290 may be performed. For example, the receiver 270 may receive a second RF signal RF2 from a second antenna 290. In operation S64a, an operation of generating a second baseband signal BB2 from the second RF signal RF2 may be performed. For example, the receiver 270 may generate a second baseband signal BB2 from the second RF signal RF2 and provide the second baseband signal BB2 to the data processor 210.

Next, in operation S80a, an operation of compensating for the nonlinearity of the transmitter 230 based on the second baseband signal BB2 may be performed.

Referring to fig. 15B, the second device 22 may generate feedback to compensate for non-linearity of a transmitter included in the first device 21. In fig. 15B, it is assumed that the first device 21 includes the components of the first device 900 of fig. 9.

In operation S20b, the first device 21 may generate a first baseband signal BB 1. Next, in operation S40b, the first device 21 may transmit a first RF signal RF1 to the second device 22. For example, the first device 21 may include a first antenna 950 and transmit the first RF signal RF through the first antenna 950.

In operation S60b, an operation of generating and obtaining feedback may be performed. As shown in fig. 15B, operation S60B may include a plurality of operations S62B, S64B, and S66B. In operation S62b, the second device 22 may obtain a second RF signal RF 2. For example, the second device 22 may include a second antenna 92 and receive the second RF signal RF2 through the second antenna 92. In operation S64b, an operation of generating feedback may be performed. For example, the second baseband signal BB2 may be generated from the second RF signal RF2 and the feedback may be generated based on the second baseband signal BB 2. In operation S66b, the second device 22 may provide feedback to the first device 21. For example, the second device 22 may provide feedback to the first device 21 over the same wireless channel over which the first RF signal RF1 was transmitted. Alternatively, the second device 22 may provide feedback to the first device 21 over a communication channel different from the wireless channel over which the first RF signal RF1 is transmitted.

Next, in operation S80b, the first device 21 may perform an operation of compensating for the nonlinearity of the transmitter 930 based on the feedback.

Fig. 16 is a flowchart of a method of compensating for nonlinearity of a transmitter according to an exemplary embodiment of the inventive concept. For example, fig. 16 illustrates a method of compensating for non-linearities of a transmitter configured to provide a plurality of first RF signals to an antenna array. The method of fig. 16 may be performed, for example, by the apparatus 600 of fig. 6 or the first apparatus 900d of fig. 13. Hereinafter, the method of fig. 16 will be described with reference to fig. 6. In fig. 16, the same description as fig. 14 may be omitted.

In operation S20', an operation of generating the first baseband signal BB1 may be performed. In operation S40', an operation of sequentially transmitting the plurality of first RF signals RF11 through RF1m may be performed. For example, the controller 614 may control the plurality of switches 640_1 to 640_ m and sequentially transmit the plurality of first RF signals RF11 to RF1 m. In operation S60', an operation of obtaining a plurality of feedbacks may be performed. For example, the receiver 670 may sequentially receive a plurality of second RF signals corresponding to the plurality of first RF signals RF11 through RF1m through the second antenna 690 and generate a plurality of second baseband signals corresponding to the plurality of second RF signals.

In operation S80', an operation based on the nonlinearity of the feedback compensation transmitter 630 may be performed. Such as

As shown in fig. 16, operation S80' may include a plurality of operations S82, S84, and S86. In operation S82, an operation of estimating a plurality of phase shifts may be performed. For example, referring to equation 4, controller 614 may calculateAveraging and estimating (shifter) of m feedbacks over a predetermined period of time_i+path_i) (1. ltoreq. i. ltoreq.m). In operation S84, an operation of normalizing the plurality of feedbacks may be performed. For example, the normalized second baseband signal BB _ norm_iCan be expressed by equation 5 (1. ltoreq. i.ltoreq.m):

BB2_norm_i＝BB2·exp(-j·(shifter_i+path_i)) (5)。

in operation S86, an operation of setting at least one parameter may be performed. For example, the controller 614 may calculate an average value of the m normalized second baseband signals, provide the setting signal SET to the predistorter 612, and SET at least one parameter for defining predistortion based on the average value.

Fig. 17 is a flowchart of an example of operation S40 and operation S60 of fig. 14, according to an exemplary embodiment of the inventive concept. For example, fig. 17 shows an example of antenna array forming beams to generate feedback. As described above with reference to fig. 14, the operation of transmitting the first RF signal RF1 may be performed in operation S40 ″ of fig. 17, and the operation of obtaining feedback based on the first RF signal RF1 may be performed in operation S60 ″ of fig. 17. For example, operations S40 "and S60" of fig. 17 may be performed by the apparatus 500 of fig. 5 or the first apparatus 900c of fig. 12. Hereinafter, fig. 17 will be described with reference to fig. 5.

Referring to fig. 17, operation S40 ″ may include operation S42 and operation S44. In operation S42, an operation of controlling the phase shifters PS1 to PSm may be performed such that the beam 4 is directed toward the second antenna 590. For example, the controller 514 may generate the first control signal C1 and provide the first control signal C1 to the transmitter 530 such that the plurality of first RF signals RF 11-RF 1m form the beam 4 toward the second antenna 590. The plurality of phase shifters PS1 to PSm may shift the phase of the plurality of first RF signals RF11 to RF1m in response to the first control signal C1.

In operation S44, an operation of providing the plurality of first RF signals RF11 to RF1m to the plurality of first antennas 550_1 to 550_ m may be performed. For example, the transmitter 530 may provide the plurality of first RF signals RF11 to RF1m shifted in phase by the plurality of phase shifters PS1 to PSm to the plurality of first antennas 550_1 to 550 — m.

Referring to fig. 17, operation S60 ″ may include operation S62 and operation S64. In operation S62, an operation of obtaining a second RF signal RF2 through the second antenna 590 may be performed. For example, the receiver 570 may receive a second RF signal RF2 from a second antenna 590.

In operation S64, an operation of generating a second baseband signal BB2 from the second RF signal RF2 may be performed. For example, the receiver 570 may generate a second baseband signal BB2 from the second RF signal RF2 and provide the second baseband signal BB2 to the data processor 510. The beam 4 formed in operation S40 ″ may be received to generate the second baseband signal BB 2. Unlike the example of obtaining multiple feedbacks described with reference to fig. 16, in an exemplary embodiment of the inventive concept, a single feedback may be obtained and the nonlinearity of the transmitter 530 may be compensated based on the single feedback.

Fig. 18 is a block diagram of a communication apparatus 50 according to an exemplary embodiment of the inventive concept. As shown in fig. 18, the communication device 50 may include an Application Specific Integrated Circuit (ASIC)51, an application specific instruction set processor (ASIP)53, a memory 55, a main processor 57, and a main memory 59. At least two of the ASIC 51, ASIP 53, and main processor 57 may communicate with each other. Further, at least one of the ASIC 51, the ASIP 53, the memory 55, the main processor 57, and the main memory 59 may be embedded in one chip.

ASIP 53 may be an IC customized for a particular purpose. ASIP 53 may support a dedicated instruction set for a particular application and may execute instructions included in the instruction set. The memory 55 may be in communication with the ASIP 53. The memory 55 may be a non-transitory storage device configured to store a plurality of instructions for execution by the ASIP 53. For example, memory 55 may include, but is not limited to, any type of memory accessible by ASIP 53, such as Random Access Memory (RAM), Read Only Memory (ROM), magnetic tape, magnetic disk, optical disk, volatile memory, non-volatile memory, and combinations thereof.

Main processor 57 may execute a number of instructions and control communication device 50. For example, the main processor 57 may control the ASIC 51 and the ASIP 53 and process data received through the MIMO channel or process user input to the communication apparatus 50. The main memory 59 may communicate with the main processor 57. The main memory 59 may be a non-transitory storage device configured to store a plurality of instructions for execution by the main processor 57. For example, the main memory 59 may include, but is not limited to, any type of memory accessible by the main processor 57, such as RAM, ROM, magnetic tape, magnetic disk, optical disk, volatile memory, non-volatile memory, and combinations thereof.

The above-described method of compensating for the nonlinearity of the transmitter according to an exemplary embodiment of the inventive concept may be performed by at least one component included in the communication apparatus 50 of fig. 18. For example, the data processor(s) described above may include at least one of an ASIC 51, an ASIP 53, a memory 55, a main processor 57, and a main memory 59. In an exemplary embodiment of the inventive concept, at least one of the above-described operations of the method of compensating for the nonlinearity of the transmitter may be implemented as a plurality of instructions stored in the memory 55. In an exemplary embodiment of the inventive concept, the ASIP 53 may execute a plurality of instructions stored in the memory 55 and perform at least one of operations of the method of compensating for the nonlinearity of the transmitter. In an exemplary embodiment of the inventive concept, at least one of the operations of the method of compensating for the nonlinearity of the transmitter may be implemented as a hardware block designed by logic synthesis and included in the ASIC 51. In an exemplary embodiment of the inventive concept, at least one of the operations of the method of compensating for the nonlinearity of the transmitter may be implemented as a plurality of instructions stored in the main memory 59. The main processor 57 may execute a plurality of instructions stored in the main memory 59 and may perform at least one of the operations of the method of compensating for the nonlinearity of the transmitter.

While the present inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

Claims

1. A communication device, comprising:

a transmitter for providing a first radio frequency signal to a first antenna such that the first antenna outputs the first radio frequency signal;

a second antenna for receiving the first radio frequency signal from the first antenna to generate a second radio frequency signal;

a receiver configured to receive the second radio frequency signal from the second antenna, wherein the receiver generates a feedback signal according to the second radio frequency signal; and the number of the first and second groups,

a controller configured to control predistortion based on the feedback signal.

2. The communication device of claim 1, further comprising a predistorter, wherein the controller controls the predistorter to perform the predistortion based on the feedback signal.

3. The communication apparatus of claim 2, wherein the predistorter generates a baseband signal by performing the predistortion based on the feedback signal and provides the baseband signal to the transmitter.

4. The communication device of claim 1, wherein the first antenna comprises an antenna array, the first radio frequency signal comprises a plurality of radio frequency signals, and the second radio frequency signal is based on at least one of the plurality of radio frequency signals.

5. The communication device of claim 1, wherein the first antenna comprises an antenna array, the first radio frequency signal comprises a plurality of radio frequency signals, the antenna array outputs the plurality of radio frequency signals to form a beam, and the second radio frequency signal is based on the beam.

6. The communication apparatus of claim 5, wherein the transmitter comprises a plurality of phase shifters, and the controller is configured to control the plurality of phase shifters to direct the beam toward the second antenna.

7. The communication device of claim 1, wherein the first antenna comprises a plurality of antennas and the first radio frequency signal comprises a plurality of radio frequency signals, the communication device further comprising a plurality of switches, each switch of the plurality of switches connected between the transmitter and a corresponding antenna of the plurality of antennas, the controller configured to control the plurality of switches to transmit the plurality of radio frequency signals to the plurality of antennas, respectively, and the receiver configured to generate the feedback signal based on the plurality of radio frequency signals output from the plurality of antennas, respectively.

8. The communication apparatus of claim 7, wherein the receiver is configured to generate the feedback signal by averaging the plurality of radio frequency signals.

9. The communication device of claim 1, wherein the first antenna is one antenna of an antenna array, the second antenna is another antenna of the antenna array, and the communication device further comprises a plurality of switches for connecting the antenna array to the transmitter or the receiver.

10. The communication apparatus of claim 9, wherein the controller is configured to control a first switch of the plurality of switches such that the first radio frequency signal is transmitted through the first antenna, and wherein the controller is further configured to control a second switch of the plurality of switches such that the receiver receives the second radio frequency signal from the second antenna.

11. The communication device of claim 1, further comprising an isolator between the first antenna and the second antenna.

12. The communication device of claim 11, wherein the isolator is configured to provide a variable coupling between the first antenna and the second antenna.

13. A communication system, comprising:

a first apparatus comprising a transmitter to output a first radio frequency signal through a first antenna; and a second apparatus comprising a second antenna for receiving the first radio frequency signal to generate a second radio frequency signal, a receiver for receiving the second radio frequency signal from the second antenna, and a feedback generator for generating a feedback signal from the second radio frequency signal,

wherein the first apparatus further comprises a controller configured to control predistortion in response to a feedback signal provided from the second apparatus.

14. The communication system of claim 13, wherein the feedback signal is provided from the second device to the first device over a wired signal path.

15. The communication system of claim 13, wherein the first device further comprises an interface circuit to receive an encoded signal from the second device as the feedback signal and to decode the encoded signal according to a protocol.

16. The communication system of claim 13, wherein the feedback generator of the second apparatus comprises a modulator to provide the feedback signal to the first apparatus over a wireless channel.

17. The communication system of claim 16, wherein the first radio frequency signal and the feedback signal are transmitted over the same wireless channel.

18. The communication system of claim 13, wherein the first antenna comprises an antenna array, the first radio frequency signal comprises a plurality of radio frequency signals, the antenna array outputs the plurality of radio frequency signals to form a beam, and the second radio frequency signal is based on the beam.

19. The communication system of claim 13, wherein the first antenna comprises a plurality of antennas and the first radio frequency signal comprises a plurality of radio frequency signals, the first device further comprising a plurality of switches, each switch of the plurality of switches connected between the transmitter and a respective antenna of the plurality of antennas,

wherein the controller is configured to control the plurality of switches to sequentially transmit the plurality of radio frequency signals to the plurality of antennas,

wherein the receiver is configured to generate a plurality of baseband signals based on the plurality of radio frequency signals output from the plurality of antennas, and,

wherein the feedback generator is configured to generate the feedback signal based on the plurality of baseband signals.

20. A method of compensating for transmitter non-linearity, comprising:

generating a baseband signal at a predistorter of a communication device;

generating a first radio frequency signal from the baseband signal at a transmitter of the communication device and transmitting the first radio frequency signal through a first antenna of the communication device;

receiving the first radio frequency signal through a second antenna of the communication device to generate a second radio frequency signal, and generating a feedback signal at a receiver of the communication device from the second radio frequency signal; and

compensating for non-linearity of the transmitter based on the feedback signal.

21. The method of claim 20, wherein the baseband signal is a training signal.

22. The method of claim 20, wherein the baseband signal is generated from a transmission signal received by the predistorter.

23. The method of claim 20, wherein the predistortion of the predistorter is set based on the feedback signal.

24. The method of claim 20, wherein the feedback signal is a baseband signal.

25. A communication device, comprising:

a predistorter configured to generate a first baseband signal;

a transmitter configured to generate a first radio frequency signal from the first baseband signal;

a first antenna configured to output the first radio frequency signal;

a second antenna configured to receive the first radio frequency signal and output a second radio frequency signal corresponding to the first radio frequency signal;

a receiver configured to generate a feedback signal from the second radio frequency signal; and

a controller configured to receive the feedback signal and estimate a nonlinearity of the transmitter based on the reflected signal.