System And Selecting Method For Flexible Allocations Of Antenna Sub-Arrays In Multiple Input Multiple Output Systems

Abstract

The invention provides a selection circuit and method of multiple input/output ports and antenna sub-arrays for reconfigurable hybrid beamforming. The selection circuit includes a plurality of digital signal processing modules, each electrically connected to a respective input/output port, a plurality of analog front end (AFE) and radio frequency (RF) chains, each electrically connected to a respective digital signal processing module, a plurality of multiplexing circuits, each electrically connected to any number of the AFE and RF chains, and a plurality of antenna sub-arrays, each electrically connected to a respective multiplexing circuit, wherein the multiplexing circuits set any number of the antenna sub-arrays to transmit/receive any number of electrical signals of input/output ports transmitted by the AFE and RF chains. The invention further provides a signal processing and transmission/reception system and a combination selection method of multiple input/output ports and antenna sub-arrays based on the selection circuit.

Claims

1. A selection circuit of multiple input/output ports and antenna sub-arrays combination, comprising: a plurality of digital signal processing modules, each is electrically connected to one of a plurality of input/output ports; a plurality of analog front end (AFE) and radio frequency (RF) chains, each is electrically connected to one of the digital signal processing modules; a plurality of multiplexing circuits, each is electrically connected to any number of the AFE and RF chains; and a plurality of antenna sub-arrays, each is electrically connected to a one of the multiplexing circuits, and the multiplexing circuits set any number of the antenna sub-arrays to transmit/receive any number of input/output electrical signals of the AFE and RF chains, wherein antenna sub-arrays comprise: a plurality of phase shifters, each is electrically connected to one of the multiplexing circuits; a plurality of power amplifiers, each is electrically connected to one of the phase shifters; and a plurality of antenna ends, each is electrically connected to one of the power amplifiers.

2. The selection circuit of claim 1, wherein the antenna sub-arrays have different polarization direction combinations.

3. A signal processing and transmission/reception system, comprising: a transmission end, comprising: a precoder, for encoding a data signal by using a signal processing method to output a plurality of first electrical signals; and a first selection circuit of multiple input ports and antenna sub-arrays combination as claim 1, for inputting the plurality of first electrical signals into input ports, and transmitting a wireless signal by an antenna sub-array combination; and a reception end, comprising: a second selection circuit of multiple output ports and antenna sub-arrays combination as claim 1, for receiving the wireless signal by receiving antenna sub-array combination from a plurality of output ports, and generating a plurality of second electrical signals; and an equalizer, for combing the plurality of second electrical signals by using the signal processing method, and outputting the data signal.

4. A selection method of multiple input/output ports and antenna sub-arrays combination, is applied in a signal processing and transmission/reception system as claim 3, the method comprising: (a) the system starts up a first multiple input/output port and antenna sub-array combination, and transmitting a test signal via a transmission end, a reception end replies a channel state information (CSI) to the transmission end after receiving the test signal, wherein the channel state information corresponds to channel statistic information of spatial and frequency generated by the first multiple input/output port and antenna sub-array combination; (b) the transmission end designs a first procoder (w) according to the channel state information, and estimating a first reception channel capacity (C); (c) determining a relationship of configurations and polarizations between the first procoder (w) and the first antenna sub-array combination, and first reception channel capacity (C), providing a multiple input/output port and antenna sub-array combination; and (d) generating a plurality of first electrical signals corresponding to the antenna sub-array combination by encoding and arranging according to the provided multiple input/output port and the antenna sub-array combination.

5. The selection method of claim 4, wherein the step (c) further comprises: (c1) determining whether a rank of the first procoder (w) is greater than or equal to a first predetermined value, if yes, providing a second multiple input/output port and antenna sub-array combination, and performing the step (c2), if no, determining the polarization of the antenna sub-array corresponding to the maximum eigenvalue of the first procoder (w) ww.sup.H, providing a third multiple input/output port and antenna sub-array combination, and performing the step (d); (c2) repeating the step (a) and step (b), starting up the second multiple input/output port and antenna sub-array combination, designing a second procoder according to the channel state information, and estimating a second reception channel capacity (Ĉ), determining whether the second reception channel capacity (Ĉ) is greater than the first reception channel capacity (C), if no, providing the first multiple input/output port and antenna sub-array combination and performing the step (d), if yes, further determining whether the rank of the second procoder (w) is smaller than or equal to a second predetermined value, if no, determining the polarization of the antenna sub-array corresponding to the maximum eigenvalue of the second procoder (w) ww.sup.H, providing a fourth multiple input/output port and antenna sub-array combination and performing the step (c3), if yes, performing the step (c4); (c3) repeating the step (a) and step (b), starting up the fourth multiple input/output port and antenna sub-array combination, estimating a fourth reception channel capacity (Ĉ), determining whether the fourth reception channel capacity (Ĉ) is smaller than the second reception channel capacity (C), if yes, providing the second multiple input/output port and antenna sub-array combination, and performing the step (d), if no, providing the fourth multiple input/output port and antenna sub-array combination, and performing the step (d); (c4) determining whether polarizations of the antenna sub-arrays corresponding to nonzero eigenvalues of the second procoder (w) ww.sup.H are identical, if no, providing a fifth multiple input/output port and antenna sub-array combination, and performing the step (c5), if yes, setting the second multiple input/output port and antenna sub-array combination as a predetermined input/output mode, and performing the step (c6); (c5) repeating the step (a) and step (b), starting up the fifth multiple input/output port and antenna sub-array combination, and estimating a fifth reception channel capacity (Ĉ), determining whether the fifth reception channel capacity (Ĉ) is smaller than the second first reception channel capacity (C), if yes, providing the second multiple input/output port and antenna sub-array combination and performing the step (d), if no, setting the fifth multiple input/output port and antenna sub-array combination as the predetermined input/output mode, and performing the step (c6) to design a fifth procoder; and (c6) determining the polarization of the antenna sub-array corresponding to the maximum eigenvalue of a procoder(w) ww.sup.H of predetermined input/output mode, providing a sixth multiple input/output port and antenna sub-array combination, and performing the step (c7); and (c7) repeating the step (a) and step (b), starting up the sixth multiple input/output port and antenna sub-array combination, and estimating a sixth reception channel capacity (Ĉ), determining whether the sixth reception channel capacity (Ĉ) is greater than or equal to a reception channel capacity (C) of a predetermined input/output mode, if yes, providing the six multiple input/output port and antenna sub-array combination, and performing the step (d), if no, providing the antenna sub-array combination of the predetermined input/output mode, and performing the step (d).

6. The combination selection method of claim 4, wherein the channel state information comprises a statistic value T of channel correlation matrix between multiple input ports of a transmission end in frequency domain, a statistic value R of channel correlation matrix between multiple output ports of a reception end in frequency domain, a statistic value of channel coefficients between multiple input output ports of a transmission end and multiple output ports of a reception end in frequency domain, and a signal-to-noise ratio (SNR).

7. The combination selection method of claim 6, wherein the reception channel capacities are the averages of channel capacities of respective used channels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1a is the schematic diagram of a conventional partially connected hybrid beamforming architecture.

[0019] FIG. 1b is the schematic diagram of a conventional fully connected hybrid beamforming architecture.

[0020] FIG. 2 is a schematic diagram of a selection circuit between AFE and RF chains and antenna sub-arrays according to an embodiment of the present invention.

[0021] FIGS. 3a and 3b are schematic diagrams of a signal processing and transmission/reception system according to an embodiment of the present invention.

[0022] FIG. 4a to FIG. 4c are schematic diagrams of antenna sub-array combination of transmission end according to embodiments of the present invention.

[0023] FIG. 5 is a schematic diagram illustrating a wireless transmission environment equipped with a signal transmission/reception system according to an embodiment of the present invention.

[0024] FIG. 6 is a schematic diagram illustrating antenna sub-array combination of transmission end and reception end according to an embodiment of the present invention.

[0025] FIG. 7a to FIG. 7c are schematic diagrams illustrating a combination selection method according to embodiments of the present invention.

[0026] FIG. 8 is a schematic diagram of a channel capacity versus the transmit power of a first wireless transmission environment according to embodiments of the present invention.

[0027] FIG. 9 is a schematic diagram of a channel capacity versus the transmit power of a second wireless transmission environment according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention relates to a multiple-input multiple-output (MIMO) technology. The MIMO technology adopts multiple antennas at the transmitting end or the receiving end for improving transmission efficiency.

[0029] The MIMO technology may increase system throughput and transmission reliability without increasing the required bandwidth and output power. In a MIMO system, the transmission energy can be distributed to different antennas for transmission signal, it can enhance the spectrum efficiency (bits per second per hertz). Moreover, the same signal can be received via different channels simultaneously in the MIMO system, thus reducing the channel fading effect.

[0030] Precoding is one of the practical techniques for the MIMO system. Precoding is a multi-stream beamforming technique. Beamforming is a signal processing technique, which processes signals with matrix operation before transmitting or receiving by the less noisy channels. In other words, precoding technique is a way to enhance signal intensity and to reduce the multipath channel fading. The precoding technique requires channel state information (CSI) associated with reception channel capacity. The channel state information can be obtained by using channel estimation method. For example, it can send pilot symbols for the reception end to estimate the channel state information and send it to a transmission end via a feedback method, and generates the beamforming matrix. Another example is estimating the channel between the transmission end to the reception end by the transmission end according to reverse channel information from the transmission end to the reception end. Based on the MIMO and precoding techniques, the invention provides a selection circuit 200 of multiple input/output ports and antenna sub-arrays for reconfigurable hybrid beamforming. Please refer to FIG. 2, which is a schematic diagram of a selection circuit 200 according to an embodiment of the present invention. The selection circuit 200 includes a plurality of digital signal processing modules, a plurality of analog front end (AFE) and radio frequency (RF) chains 210, a plurality of multiplexing circuits 220 and a plurality of antenna sub-arrays 230.

[0031] Each AFE and RF chain 210 is electrically connected to one of the digital signal processing module. Each digital signal processing module is electrically connected to a one of a plurality of input/output ports. Each multiplexing circuit 220 is electrically connected to any number of the AFE and RF chains 210. Each antenna sub-array 230 is electrically connected to one of the multiplexing circuits 220, and the multiplexing circuits 220 can set any number of the antenna sub-arrays 230 to transmit/receive any number of input/output electrical signals of the AFE and RF chains 210.

[0032] Wherein each antenna sub-array 230 includes a plurality of phase shifters 231, a plurality of power amplifiers 232 and a plurality of antenna ends 233.

[0033] Each phase shifter 231 is electrically connected to one of the multiplexing circuit 231. Each power amplifier 232 is electrically connected to one of the phase shifter 231. Each antenna end 233 is electrically connected to power amplifier 232. Preferably, the antenna sub-arrays have different polarization direction combinations.

[0034] Please refer to FIG. 3a and FIG. 3b, the invention further provides a signal processing and transmission/reception system. The signal processing and transmission/reception system includes a transmission end and a reception end. The transmission end includes a precoder 311 and an above-mentioned first selection circuit 310 of multiple input ports and antenna sub-arrays combination. The precoder 311 is used to encode a data signal by using a signal processing method to output a plurality of first electrical signals.

[0035] In the first selection circuit 310, a unit including a plurality of multiplexing circuits 312 can be connected to the corresponding AFE and RF chain 313. The plurality of first electrical signals can be inputted via a digital signal processing (DSP) module 314. An antenna sub-array combination 315 can be arranged by the multiplexing circuits 312 for transmitting a wireless signal.

[0036] Similar to the transmission end, the reception end includes an above-mentioned second selection circuit 320 of multiple input ports and antenna sub-arrays, and an equalizer 321.

[0037] In the second selection circuit 320, an antenna sub-array combination 325 can be arranged by a unit including a plurality of multiplexing circuits 322 for receiving the wireless signal. The unit including a plurality of multiplexing circuits 322 can be connected to the corresponding AFE and RF chain combination 323. Therefore, a plurality of second electrical signals can be generated by a digital signal processing module 324 and outputted to the equalizer 321. The equalizer 321 is utilized for combing the plurality of second electrical signals by using a signal processing method, and outputting the data signal.

[0038] Please refer to FIG. 4a to FIG. 4c, which show the antenna sub-arrays of the transmission end. In an embodiment, the transmission end has eight antenna sub-arrays. Each number represents an antenna sub-array, the same/different number represents the same/different antenna sub-array combination. As shown in FIG. 4a, the eight antenna sub-arrays are arranged to eight antenna sub-array combinations (denoted by 1 to 8) for transmitting a wireless signal. As shown in FIG. 4b, every two antenna sub-arrays from one antenna sub-array combination. Therefore, there are four antenna sub-array combinations (denoted by 1 to 4) for transmitting the wireless signal. As shown in FIG. 4c, every four antenna sub-arrays from one antenna sub-array combination. Thus, there are two antenna sub-array combinations (denoted by 1 to 2) for transmitting the wireless signal. Each antenna sub-array combination corresponds to a respective AFE and RF chains 210, a respective digital signal processing module, connected input/output ports. And this is not a limitation of the present invention.

[0039] Please refer to FIG. 5, which illustrates a wireless transmission environment equipped with a signal transmission/reception system. A transmission end or a reception end 520 can be a mobile device, a computer, an antenna station, etc. The reception end 520 is equipped with a selection circuit of multiple input/output ports and antenna sub-array. In an embodiment, the transmission end has eight antenna sub-arrays and the reception end has four antenna sub-arrays. The combination selection method can arrange various antenna sub-arrays combinations and estimate the link qualities of different channels so as to find the best signal transmission method.

[0040] Please refer to FIG. 6, which illustrating antenna sub-array combination of transmission end and reception end according to an embodiment of the present invention. As shown in FIG. 6, various antenna sub-arrays are arranged to form multiple input multiple output modes (MIMO modes) by using the combination selection method of multiple input/output ports and antenna sub-arrays. In the above-mentioned embodiments, if the input end arranges four output antenna sub-array (TX array) combinations. Each antenna sub-array combination corresponds to an AFE and RF chain, a digital signal processing module and connected input ports. And, the reception end arranges four output antenna sub-array (RX array) combinations. Each antenna sub-array combination corresponds to an AFE and RF chain, a digital signal processing module and connected output ports. In such a situation, the multiple input multiple output combination mode can be represented by 4×4 (mode 2).

[0041] In another embodiment, if the input end arranges one output antenna sub-array combination, and the reception end arranges two reception antenna sub-array combinations. In such a situation, the multiple input multiple output combination mode can be represented by 1×2 (mode 9). And this is not a limitation of the present invention, The combination selection method of multiple input/output port and antenna sub-array of the present invention can arrange various antenna sub-arrays combinations and estimate the link quality of different channels so as to find the best signal transmission method.

[0042] Please refer to FIG. 7a to FIG. 7c. The invention provides a combination selection method of multiple input/output ports and antenna sub-arrays combination, which is applied in a signal processing and transmission/reception system maintained above. The combination selection method includes the following steps: in FIG. 7a, (a) (Step S710) the system enables starts up a first multiple input/output port and antenna sub-array combination and controls a transmission end to transmit a test signal. After receiving the test signal, a reception end replies channel state information (CSI) to the transmission end. The channel state information corresponds to channel statistic information of spatial and frequency generated by the first multiple input/output port and antenna sub-array combination. Preferably, the channel state information includes a statistic value T of channel correlation matrix between multiple input ports of a transmission end in frequency domain, a statistic value R of channel correlation matrix between multiple output ports of a reception end in frequency domain, a statistic value of channel coefficients between multiple input ports of a transmission end and multiple output ports of a reception end in frequency domain, and a signal-to-noise ratio (SNR, p/ρw2).

[0043] (b) the transmission end designs a first procoder(w) according to the channel state information and estimating a first reception channel capacity (C) (Step S720). Preferably, the reception channel capacities are averages of channel capacities of respective use channels.

[0044] (c) determining a relationship of configurations and polarizations between eigenvalues of the first procoder(w) and configurations and polarizations of the first antenna sub-array combination, and first reception channel capacity (C), providing a multiple input/output port and antenna sub-array combination (Step S730). Preferably, in FIG. 7b and FIG. 7c, the step (c) further includes the following steps. (c1) determining whether the rank of the first procoder (w) is greater than or equal to a first predetermined value (Step S731). If yes, providing a second multiple input/output port and antenna sub-array combination and performing the step (c2). If no, determining the polarization of the antenna sub-array corresponding to the maximum eigenvalue of the first procoder(w) ww.sup.H providing the third multiple input/output port and antenna sub-array combination, wherein ww.sup.H represents the product of the encoding characteristic matrices (Step S731 a) and performing the step (d).

[0045] (c2) repeating the step (a) and step (b), starting up the second multiple input/output port and antenna sub-array combination, designing a second procoder according to the channel state information, estimating a second reception channel capacity (Ĉ), and determining whether the second reception channel capacity (Ĉ) is greater than the first reception channel capacity (C) (Step S732). If not, providing the first multiple input/output port and antenna sub-array combination (Step S732a), and performing the step (d). If yes, further determining whether a rank of the second procoder (w) is smaller than or equal to a second predetermined value (Step S733); if no, determining the polarization of the antenna sub-array corresponding to the maximum eigenvalue of the second procoder(w) ww.sup.H providing the fourth multiple input/output port and antenna sub-array combination and performing the step (c3) (Step S734); if so, performing the step (c4) (Step S735).

[0046] (c3) repeating the step (a) and step (b), enabling the fourth multiple input/output port and antenna sub-array combination, estimating a fourth reception channel capacity (Ĉ), determining whether the fourth reception channel capacity (Ĉ) is smaller than the second reception channel capacity (C); if yes, providing the second multiple input/output port and antenna sub-array combination (Step S734a) and performing the step (d); if no, providing the fourth multiple input/output port and antenna sub-array combination (Step S734b) and performing the step (d).

[0047] (c4) determining whether the polarizations of the antenna sub-array corresponding to nonzero eigenvalues of wwH of the second procoder(w) are identical (Step S735); if no, providing a fifth multiple input/output port and antenna sub-array combination and performing the step (c5) (Step S736); if yes, setting the second multiple input/output port and antenna sub-array combination as a predetermined input output mode and performing the step (c6) (Step S737).

[0048] (c5) repeating the step (a) and step (b), enabling the fifth multiple input/output port and antenna sub-array combination and estimating a fifth reception channel capacity (Ĉ), determining whether the fifth reception channel capacity (Ĉ) is smaller than the second reception channel capacity (C); if so, providing the second multiple input/output port and antenna sub-array combination (Step S736a) and performing the step (d); if not, setting the fifth multiple input/output port and antenna sub-array combination as a predetermined input output mode (Step S736b) and performing the step (c6) to design a fifth procoder.

[0049] (c6) determining the polarization of the antenna sub-array corresponding to the maximum eigenvalue of the procoder (w) ww.sup.H of a predetermined input output mode, providing a sixth multiple input/output port and antenna sub-array combination (Step S737a) and performing the step (c7).

[0050] (c7) repeating the step (a) and step (b), starting up the sixth multiple input/output port and antenna sub-array combination and estimating a sixth reception channel capacity (Ĉ), determining whether the sixth reception channel capacity (Ĉ) is greater than or equal to the reception channel capacity (C) of predetermined input output mode (Step S738); if yes, providing the six multiple input/output port and antenna sub-array combination (Step S738a) and performing the step (d); if no, providing the antenna sub-array combination of predetermined input output mode (Step S738b) and performing the step (d).

[0051] (d) generating a plurality of first electrical signals corresponding to the output antenna sub-array combination by encoding and arranging according to the provided multiple input/output port and the antenna sub-array combination (Step S740).

[0052] Please refer to FIG. 8, which is a schematic diagram illustrating a channel capacity versus the selection transmission power of in a first wireless transmission environment. Referring to the section 810 shown in the upper left of FIG. 8, the transmission end and the reception end are located in the same horizontal plane in FIG. 5. A beam is emitted by the output antenna sub-array and reflected once by the wall. After being reflected once by a wall, the beam reaches the receiving antenna sub-array. In such a situation, the x-polarized antenna has a larger antenna gain than the y-polarized antenna in the reflection path. Referring to the section 820 shown in the bottom left of FIG. 8 and the section 920 shown in the bottom left of FIG. 9, the section 820 shows a cylindrical coordinate diagram of the electric field intensity of the respective x-polarized antenna, and the section 920 shows a cylindrical coordinate diagram of the electric field intensity of the respective y-polarized antenna. In comparison, there is a better beam width of antenna in the x direction shown in the section 820 of FIG. 8, since the antenna current is driven along the x direction and both of the transmission end and the reception end are located in the same horizontal plane of FIG. 5, and the signal is mainly transmitted via reflection in the x direction.

[0053] Furthermore, comparing the signal transmission power of different multiple input multiple output modes, please further refer to FIG. 8. Referring to the section 830 shown in the right hand side of FIG. 8, when the noise ratio of signal is extremely low, the channel selection method chooses the mode 8 to arrange input/output port and the antenna sub-array combination for maximizing the antenna sub-array and optimizing the channel capacity.

[0054] If the signal to noise ratio gradually increases, the channel selection method chooses the mode 6 to arrange the input/output port and the antenna sub-array combination, so as to exploit the spatial diversity for capacity enhancement. In such a situation, although the array gain of each antenna is reduced by half, the increased spatial diversity improves the channel capacity.

[0055] If the signal to noise ratio continues to increase, the system chooses the mode 3 to arrange the input/output port and the antenna sub-array combination. As shown in the section 920 of FIG. 9, although the beam width of the vertically polarized (y-polarized) antenna is narrower than the beam width of the horizontally polarized (x-polarized) antenna, there is a higher orthogonality relationship between the horizontal polarization radiation pattern and the vertical polarization radiation pattern, and the correlation of the channel coefficient between each other may be lower, it is better than the channel coefficient of two antenna sub-arrays having the same polarization in the mode 6. Moreover, the corresponding antenna sub-arrays have higher array gain. Therefore, the mode 3 configuration brings higher channel capacity.

[0056] If the signal to noise ratio further increases, the system chooses the mode 4 configuration to use four antenna sub-arrays for the arrangement of the input/output port and the antenna sub-array combination, so as to exploit the spatial diversity for capacity enhancement. Similarly, if the noise ratio of signal further increases, the system chooses the mode 2 configuration to arrange of the input/output port and the antenna sub-array combination, so as to exploit the spatial diversity for capacity enhancement.

[0057] Compared to the conventional hybrid beamforming using eight antenna sub-arrays, the transmission rate of the reconfigurable hybrid beamforming of the invention can be increased by 500%-35% (e.g., the transmission rate may reach 5-25 (bit/sec/channel)) when the output power is between 0 dBm-30 dBm. On the other hand, when the transmission rate is between 2-32 (bit/sec/channel), the reconfigurable hybrid beamforming of the invention has 15 dB-3 dB gain greater than the conventional hybrid beamforming using eight antenna sub-arrays.

[0058] Please refer to FIG. 9, which is a schematic diagram illustrating a channel capacity versus the transmission power of a second wireless transmission environment. Referring to the section 910 shown in the upper left of FIG. 9, the transmission end and the reception end are located in the same vertical planes. A beam is emitted by the output antenna sub-array and reflected once in FIG. 5. The beam reaches the receiving antenna sub-array after being reflected once in FIG. 5. In such a situation, the y-polarized antenna has a larger antenna gain than the x-polarized antenna in the reflection path. Referring to the section 920 shown in the bottom left of FIG. 9 and the section 820 shown in the bottom left of FIG. 8, the section 920 shows a cylindrical coordinate diagram of the electric field intensity of respective y-polarized antenna and the section 820 shows a cylindrical coordinate diagram of the electric field intensity of respective x-polarized antenna. In comparison, there is a better beam width of antenna in the y direction shown in the section 920 of FIG. 9 since the antenna current is driven along the y direction and both of the transmission end and the reception end are located in the same vertical plane, and the signal is mainly transmitted via reflection in the y direction.

[0059] Furthermore, comparing the signal transmission power of different multiple input multiple output modes, please further refer to FIG. 9. Referring to the section 930 shown in the right side of FIG. 9, when the noise ratio of signal is extremely low, the channel selection method chooses the mode 9 to arrange the input/output port and antenna sub-array combination for maximizing the antenna sub-array gain and optimizing the channel capacity.

[0060] Similar to the operation in the first wireless transmission environment, when the signal to noise ratio gradually increases, the channel selection method chooses the mode 7, the mode 3 and the mode 5 in sequence to arrange the input/output port and antenna sub-array combination for the channel capacity optimization. Comparing to the conventional hybrid beamforming using eight antenna sub-arrays, the transmission rate of the reconfigurable hybrid beamforming of the invention can be increased by 500%-44% (e.g., the transmission rate may reach 1-13 (bit/sec/channel)) when the output power is between 0 dBm-30 dBm. On the other hand, when the transmission rate is between 2-26 bit/sec/channel, the reconfigurable hybrid beamforming of the invention has 12 dB-3 dB gain greater than the conventional hybrid beamforming using eight antenna sub-arrays.

[0061] According to the simulation results of the FIG. 8 and FIG. 9, the invention can estimate channel situation and arrange the number and polarization of antenna sub-arrays corresponding to multiple input/output ports via a learning and configuration selection method. In the low signal to noise ratio situation, the selection circuit can effectively increase the channel capacity with array gains, in the high signal to noise ratio situation, the selection circuit can effectively increase the channel capacity with array gains, spatial diversity and polarization diversity, as well as the system by using power allocation and precoding technique.

[0062] Although the present disclosure has been described in considerable detail with reference of embodiments maintained, other embodiments are still possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims.