CN108494458A - Signal transmitting apparatus and method based on sub-wave length analog beam former - Google Patents
Signal transmitting apparatus and method based on sub-wave length analog beam former Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
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- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
- H04B7/0842—Weighted combining
- H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
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Abstract
The invention discloses a kind of signal transmitting apparatus and method based on sub-wave length analog beam former, the method includes：Signal p is obtained into transmitting terminal time domain samples sequence after deserializer, Fourier inversion device plus cyclic prefix device and parallel-to-serial converter successivelyIt willPass through N parallel simultaneouslytA signal transmitting filter realizes the forming of sub-wave length analog beam；By the output of every road signal transmitting filter respectively by NtA signal transmission antenna is transmitted wirelessly.Symbol level ABF performances caused by the case where sub-wave length ABF may be implemented using the present invention, avoid factor intercarrier correlation weak, differ greatly decline.
Description
Technical Field
The present invention relates to the field of wireless carrier technology, and in particular, to a signal transmission device and method based on a subcarrier-level analog beamformer.
Background
In recent years, in order to meet the demand of the fifth generation mobile communication system for significant improvement of capacity and spectral efficiency, a large-scale antenna array has become a research hotspot. The large-scale antenna array can bring larger diversity gain and multiplexing gain, thereby greatly improving the spectrum efficiency of the system. Due to complexity, power consumption, cost, and other considerations, large-scale antenna array implementations typically employ a hybrid beamformer architecture.
The hybrid beamformer consists of a digital beamformer at baseband and an analog beamformer at the rf end, and a typical hybrid beamformer structure is shown in fig. 1. At the base station side, NsThe data stream is input to a Digital precoder (DBF), and output is passed throughAfter a radio frequency link, pass through a phase shifter and NtThe antennas are connected, and the phase shifter network forms an analog beam former; on the user side, NrAn antenna passing through a phase shifter andconnected by RF links and output N via digital combinersA data stream.
As an example of the behavior, to transmit multiple data streams,let s denote NsX 1 vector of transmitted symbols, FBBTo representDigital precoder of, FRFTo representThe sampled transmission signal may be represented as x ═ FRFFBBs, wherein
The conventional hybrid beamformer structure assumes a narrowband block fading channel model, so the user reception signal can be expressed as y ═ HFRFFBBs + N, wherein y represents NrX 1, H represents Nr×NtN represents additive white gaussian noise. The signal received by the user is obtained by combining the analog combiner and the digital combinerWherein wRFTo representAnalog combiner of wBBTo representR represents NsA received symbol vector of x 1.
The design of hybrid beamformers typically uses a "two-step-through" approach, i.e., the originating analog beamformer F is first designed based on the actual channel HRFAnd receive end analog combiner wRFThen according to the equivalent channelDesign originating digital beamformer FBBAnd receive digital combiner wBB. The design of the analog beamformer is usually implemented by using a codebook-based beam searching method. The simplest methods are the beam shaper andthe combiner separately traverses the beamforming codebook and selects the best beamforming vector and the best combining vector that maximize spectral efficiency.
It should be noted that the hybrid beamforming scheme is only for a narrowband communication system, i.e., a single carrier modulation system. Practical broadband communication systems typically employ Multi-carrier modulation, such as OFDM (orthogonal frequency division multiplexing), which is actually one of MCMs (Multi carrier modulation). In OFDM systems, the baseband processing is done mainly in the frequency domain, while the rf processing is done for time domain OFDM symbols after IFFT (inverse fourier transform). Therefore, after introducing the hybrid beamforming technique in the OFDM system, a structure in which the frequency domain DBF and the time domain ABF are mixed is naturally formed.
OFDM systems employ multi-carrier modulation as opposed to single carrier for narrowband communication systems. The specific implementation scheme of hybrid beamforming in the OFDM system is to calculate an equivalent channel according to the channels experienced by a plurality of carriers, design a symbol level ABF the same as that of a single carrier system, and then design a subcarrier level DBF. FIG. 2 shows a hybrid beamforming structure for an OFDM system, with N on each carriersAfter digital pre-coding, the individual streams are subjected to K-point inverse Fourier transform (IFFT), then a Cyclic Prefix (CP) is added, and the individual streams are connected with an antenna through a radio frequency link and a phase shift network. And a plurality of receiving antennas at the user side are connected with the radio frequency link through a phase shifter network, then CP is removed, and after K-point FFT, subsequent baseband processing is carried out. The baseband signal to be processed on the k-th carrier of the user can thus be represented as
That is, the above-described OFDM symbol-level ABF is equivalent to performing analog beamforming with the same vector for all subcarriers, and if the correlation between different subcarriers is weak, the symbol-level ABF processing will generate a significant capacity loss. Especially for the OFDMA system, a plurality of simultaneously scheduled users occupy different subcarriers, the difference between the subcarriers is significant, and the performance degradation of the symbol-level ABF will be more significant.
Disclosure of Invention
In view of this, the present invention provides a signal transmission apparatus and method based on a subcarrier-level analog beamformer, which implement subcarrier-level ABF and avoid performance degradation of symbol-level ABF caused by weak correlation and large difference between factor carriers.
The present invention provides a signal transmission method based on subcarrier level analog beam-former based on the above object, including:
the signal p is sequentially subjected to a serial-to-parallel converter, a Fourier inverse converter, a cyclic prefix adding device and a parallel-to-serial converter to obtain a time domain sampling point sequence of a sending end
Will be provided withPassing N simultaneously in paralleltA signal transmission filter for realizing subcarrier-level analog beam forming;
the output of each signal transmission filter is respectively divided into NtThe signal transmitting antennas perform wireless transmission.
Further, the method further comprises:
by NrA signal receiving antenna receives the signal and converts NrThe signals received by the antennas respectively pass through NrAfter receiving the filter, the signals are superposed and combined into a signal r;
and sequentially passing the signal r through a serial-to-parallel converter, a Fourier converter, a cyclic prefix remover and a parallel-to-serial converter to obtain a receiving end frequency domain sampling point sequence p'.
Wherein the signal transmit filter is determined from beamforming vectors selected for each subcarrier according to its respective channel characteristic:
determining the optimal beam forming vector of a transmitting end aiming at the subcarrier transmitted by the signal transmitting antenna connected with each signal transmitting filter;
and determining a time domain beamforming filter as the signal sending filter according to the optimal beamforming vector of the sending end.
Wherein the signal reception filter is determined from the beam combining vector selected for each subcarrier according to its respective channel characteristic:
determining the optimal beam combination vector of a receiving end aiming at the sub-carrier received by the signal receiving antenna connected with each signal receiving filter;
and determining a time domain beam combination filter as the signal receiving filter according to the optimal beam combination vector of the receiving end.
The invention also provides a signal transmission device based on the subcarrier level analog beam former, which comprises: a signal transmitting device located at the base station side; wherein the signal transmission device includes:
a serial-to-parallel converter, an inverse Fourier converter, a cyclic prefix adding device and a parallel-to-serial converter which are connected in series in sequence and used for converting the signal p into a time domain sampling point sequence of a sending end
NtA signal transmitting filter connected with the output end of the parallel-serial converter for transmitting the signalsPerforming N simultaneously in paralleltFiltering the wave to realize analog beam forming;
Ntsignal transmitting antennas respectively connected to NtA signal transmissionAnd the filters are used for respectively transmitting the output signals of the signal transmission filters in a wireless way.
The invention also provides a signal transmission device based on the subcarrier level analog beam former, which comprises: a signal receiving device located at a user side; wherein the signal transmission device includes:
Nra signal receiving antenna for receiving a wireless signal;
Nra signal receiving filter, the input end of each signal receiving filter is respectively connected with an antenna, and the output ends of the signal receiving filters are mutually connected and used for connecting NrThe signals received by the antennas respectively pass through NrFiltering the signal by a signal receiving filter, and then superposing and combining the signal into a signal r;
the device comprises a serial-to-parallel converter, a Fourier converter, a cyclic prefix remover and a parallel-to-serial converter which are sequentially connected in series and used for converting a signal r into a receiving end frequency domain sampling point sequence p'.
In the technical scheme of the embodiment of the invention, the signal is transmitted through NtBefore the signal transmitting antenna carries out wireless transmission, the signals firstly pass through N in paralleltThe signal transmitting filter performs subcarrier-level analog beamforming, so that symbol-level ABF performance of subcarriers of different channels can be guaranteed, and spectral efficiency of a system is effectively improved.
The signal transmission filter is determined according to the beamforming vector selected for each subcarrier by the respective channel characteristic, that is, the signal transmission filter designed after selecting the optimal ABF vector for each subcarrier by the respective channel characteristic can ensure the ABF performance of different subcarrier channels to the maximum extent.
Drawings
FIG. 1 is a prior art narrowband hybrid beamformer architecture;
FIG. 2 is a diagram of a hybrid beamformer structure of an OFDM system in the prior art;
fig. 3 is a conceptual diagram of a subcarrier level ABF according to an embodiment of the present invention;
fig. 4 is a structural diagram of a signal transmitting apparatus located at a base station side in a signal transmission apparatus based on a subcarrier-level analog beamformer according to an embodiment of the present invention;
fig. 5 is a structural diagram of a signal receiving apparatus located at a user side in a signal transmitting apparatus based on a subcarrier-level analog beamformer according to an embodiment of the present invention;
fig. 6 is a flowchart of a signal transmission method based on a subcarrier-level analog beamformer according to an embodiment of the present invention;
fig. 7 is a flowchart of a method for determining a signal transmission filter according to an embodiment of the present invention;
fig. 8 is a flowchart of a method for determining a signal receiving filter according to an embodiment of the present invention;
fig. 9 is a graph comparing the spectral efficiency of the ABF at subcarrier level and the ABF at symbol level in the rayleigh fading channel according to the embodiment of the present invention;
fig. 10 is a graph comparing spectral efficiencies of a subcarrier-level ABF and a symbol-level ABF in a millimeter-wave channel according to an embodiment of the present invention;
fig. 11 is a graph comparing the spectral efficiency of the subcarrier-level ABF and the symbol-level ABF in the millimeter-wave channel OFDMA system according to the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.
It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are used for distinguishing two entities with the same name but different names or different parameters, and it should be noted that "first" and "second" are merely for convenience of description and should not be construed as limitations of the embodiments of the present invention, and they are not described in any more detail in the following embodiments.
The inventor of the present invention considers that, because the channels experienced by signals on different subcarriers are different, the ABF scheme in the prior art is equivalent to performing analog beamforming by using the same vector for all subcarriers, so that the performance of the signal ABF is significantly reduced when analog beamforming is performed by using the same vector on some subcarriers. Therefore, in the technical solution of the present invention, ABFs, i.e., subcarrier levels ABFs, are respectively made for different subcarriers, and corresponding DBFs are also respectively designed for different carriers. That is, the best ABF vector is selected for each subcarrier for its respective channel characteristics; therefore, the performance degradation of symbol-level ABF caused by weak correlation and large difference among factor carriers is avoided, and the spectrum efficiency of an MIMO (Multiple-Input Multiple-Output) -OFDM system can be effectively improved.
The technical solution of the embodiments of the present invention is described in detail below with reference to the accompanying drawings.
As shown in fig. 3, a conceptual diagram of subcarrier-level ABF is considered, i.e., ABF is implemented separately for data symbols on each subcarrier before IFFT. Note the bookWhereinΒkIs the best codebook, i.e. the best beamforming vector, on the k-th subcarrier.
In codebook-based beam search, given a codebook set C ═ { C ═ C1,C2,...,CMWherein M is a codebook dimension, BETAkE.g. C, selecting the codebook which can maximize the channel capacity of the subcarrier from the codebook set as the optimal codebook.
For simplicity of explanation, only the output signal p to one radio link after digital precoding is considered ═ p1,p2,...,pKAnd (after digital precoding, processing each output signal is as follows). If frequency domain subcarrier level ABF is performed on the path of signal, the following expression one is given:
wherein,is B1～BKSet of (A), Bn＝[B1n,B2n,…,BKn]，n＝1,2,...,Nt. Then, taking IFFT by rows as the following expression two:
wherein,q＝F-1(p)，representing a cyclic convolution, F-1An IFFT is represented.
Since the OFDM system adds cyclic prefix after IFFT to the signal, the signal qTAnd bkMaking a circular convolution is equivalent to a signal qTSignals obtained after adding a cyclic prefix deviceAnd bkPerforming linear convolution, namely as shown in expression three:
based on the above analysis, the signal transmission apparatus based on subcarrier-level analog beamformer provided in the embodiment of the present invention may include a signal transmitting apparatus located at the base station side, and further may include a signal receiving apparatus located at the user side.
As shown in fig. 4, the signal transmission device includes: n is a radical oftA signal transmission filter 405 and NtA signal transmitting antenna 406, and a serial-to-parallel converter 401, an inverse fourier transformer 402, a cyclic prefix adder 403, and a parallel-to-serial converter 404 connected in series in this order.
Wherein, the serial-to-parallel converter 401, the inverse fourier transformer 402, the cyclic prefix adder 403 and the parallel-to-serial converter 404, which are connected in series in sequence, are used for converting the signal p into the time domain sampling point sequence at the transmitting end
NtThe input terminals of the signal transmission filters 405 are connected to the output terminal of the parallel-to-serial converter 404 for connectingPerforming N simultaneously in paralleltFiltering the channel to realize analog beam forming of the subcarrier; wherein N istIs a natural number greater than 0.
NtThe signal transmitting antennas 406 are respectively connected to NtThe output end of each signal transmission filter 405 is used for wirelessly transmitting the output signal of each signal transmission filter 405.
As shown in fig. 5, the signal receiving apparatus includes: serial-to-parallel converter 503, fourier transformer 504, cyclic prefix remover 505, and parallel-to-serial converter 506, connected in series in this order, and NrA signal receiving antenna 501, NrA signal receiving filter 502; further, a baseband processing unit (not shown) may be included.
Wherein N isrA signal receiving antenna 501 for receiving a wireless signal; n is a radical ofrIs a natural number greater than 0.
The input end of each signal receiving filter 502 is connected with a signal receiving antenna 501, and the output ends of the signal receiving filters 502 are connected with each other for connecting NrThe signals received by the signal receiving antenna 501 respectively pass through NrFiltering the signal by a signal receiving filter, and then superposing and combining the signal into a signal r;
the device comprises a serial-to-parallel converter 502, a Fourier converter 504, a cyclic prefix remover 505 and a parallel-to-serial converter 506 which are sequentially connected in series and used for converting a signal r into a receiving end frequency domain sampling point sequence p;
the baseband processing unit is used for carrying out other baseband processing on the p to obtain a required signal.
Based on the signal transmission device based on the subcarrier-level analog beamformer, the signal transmission method based on the subcarrier-level analog beamformer provided by the embodiment of the present invention has a flow as shown in fig. 6, and includes the following steps:
s601: the signal p is sequentially subjected to a serial-to-parallel converter, a Fourier inverse converter, a cyclic prefix adding device and a parallel-to-serial converter to obtain a time domain sampling point sequence of a sending end
Specifically, the signal p vector corresponds to K data symbols on K subcarriers, and after the serial-parallel converter 401, the inverse fourier converter 402, and the cyclic prefix adder 403 which are connected in series in sequence are used to complete K-point IFFT and add cyclic prefixes (assuming that the number of cyclic prefix points is KP), the (K + KP) symbols are parallel in form in the signal sending apparatus at the base station side; it is converted into a serial (K + KP) point time domain symbol sequence by a parallel-to-serial converter 404
S602: will be provided withPassing N simultaneously in paralleltAnd the signal transmitting filter realizes subcarrier-level analog beam forming.
Specifically, the (K + KP) point time domain symbol sequence output by the parallel-to-serial converter 404Passing N simultaneously in paralleltA signal transmit filter 405 to implement subcarrier level analog beamforming.
S603: will NtThe outputs of the signal transmission filters 405 are respectively composed of NtThe signal transmitting antennas 406 perform wireless transmission.
After the signal transmitted by the signal transmitting antenna 406 is transmitted in space, it can be received and processed by the signal receiving apparatus through the following steps:
s604: by passingNrA signal receiving antenna receives the signal and converts NrThe signals received by the antennas respectively pass through NrAfter receiving the filter, the signals are superposed and combined into a signal r;
in particular, on the user side, by N of the signal receiving meansrA signal receiving antenna 501 receives the signal and converts NrThe signals received by the signal receiving antenna 501 respectively pass through NrThe individual signals are received by filters 502 and combined into a signal r.
S605: sequentially passing the signal r through a serial-to-parallel converter, a Fourier converter, a cyclic prefix remover and a parallel-to-serial converter to obtain a receiving end frequency domain sampling point sequence p';
specifically, the signal r sequentially passes through a serial-to-parallel converter 503, a fourier converter 504, a cyclic prefix remover 505, and a parallel-to-serial converter 506 of the signal receiving apparatus to obtain a receiving-end frequency domain sample point sequence p'.
S606: and performing other baseband processing on the p'.
Specifically, p' is subjected to other baseband processing by the baseband processing unit 507 of the signal receiving apparatus.
N is as defined abovetThe individual signal transmit filters 405 are determined for the beamforming vectors selected for each subcarrier based on its respective channel characteristics, and the specific flow is shown in fig. 7 and includes the following steps:
s701: the optimal beamforming vector at the transmitting end is determined for the sub-carriers transmitted by the signal transmission antenna 406 to which each signal transmission filter 405 is connected.
In this step, a beam search is performed for the subcarriers transmitted by the signal transmitting antenna 406 connected to each signal filter, and an optimal beamforming vector at the transmitting end is found for each subcarrier.
In particular, in codebook-based beam search, given codebook set C ═ C1,C2,...,CMWhere M is the codebook dimension; for the k sub-carrierThe codebook that maximizes the channel capacity of the sub-carrier can be selected from the codebook set as the optimal codebook, i.e., the optimal beamforming vector BETA of the k-th sub-carrier at the transmitting endkE.c, K1, 2. And K is the number of subcarriers.
S702: and determining a time domain beam forming filter as the signal sending filter according to the optimal beam forming vector.
Specifically, the optimal beamforming vector for each subcarrier is arranged as shown in the following expression four:
further, the IFFT is then taken by rows, as shown in expression five:
wherein BETAkK is the best beamforming vector on the kth subcarrier, K being 1, 2. K is the number of subcarriers, F-1Representing an IFFT; to obtain NtA time domain beam forming filter ofAs the signal transmission filter.
N is as defined aboverThe signal receiving antenna 501 may be designed according to the following method, the flow of which is shown in fig. 8, and includes the following steps:
s801: the optimal beam combining vector at the receiving end is determined for the sub-carriers received by the signal receiving antenna 501 to which each signal receiving filter is connected.
In particular, in codebook-based beam search, a given codebook set E ═ { E ═ E1,E2,...,ENWhere N is the codebook dimension; for theThe kth sub-carrier may select a codebook that maximizes the channel capacity of the sub-carrier from the codebook set as an optimal codebook, i.e. the optimal beam combining vector D of the kth sub-carrier at the receiving endkE, K is 1, 2. And K is the number of subcarriers.
S802: and determining a time domain beam combination filter as the signal receiving filter according to the optimal beam combination vector.
Specifically, the optimal beam combining vector for each subcarrier is arranged as shown in the following expression six:
further, the IFFT is then taken by rows, as shown in expression seven:
in the expression six and the expression seven,is D1～DKSet of (2), DkCombining vectors for the best beam on the kth sub-carrier, K being 1, 2. K is the number of subcarriers, F-1Representing an IFFT; to obtain NrA time domain beam combining filter respectivelyAs the signal receiving filter.
The following is simulation performed for the technical scheme of the embodiment of the present invention, the simulation performance index is the spectrum efficiency, and the parameter configuration is shown in the following table:
watch 1
The rayleigh fading channel simulation result is shown in fig. 9, and the millimeter wave channel simulation result is shown in fig. 10. It can be seen that, under rayleigh fading channel, when the signal-to-noise ratio is 0dB, the spectral efficiency of the subcarrier-level ABF is improved by 2.4 times than that of the conventional symbol-level ABF; under the millimeter wave channel, when the signal-to-noise ratio is 0dB, the spectral efficiency of the subcarrier-level ABF is improved by 7% compared with that of the traditional symbol-level ABF. It can be seen that the spectral efficiency under the rayleigh channel is greatly improved, while the spectral efficiency under the millimeter wave channel is not obviously improved, mainly because the channel correlation on different subcarriers is stronger under the millimeter wave channel.
In the OFDMA system, different resource blocks are required to be allocated to different users, and at this time, channels on different resource blocks are independent of each other, and a simulated spectrum efficiency curve under the millimeter wave channel is shown in fig. 11. It can be seen that in the millimeter wave channel, the OFDMA system distributes 1200 subcarriers to 10 users on average, and when the signal-to-noise ratio is 0dB, the spectral efficiency of the subcarrier-level ABF is improved by 2.2 times compared with the conventional symbol-level ABF.
Therefore, the subcarrier-level ABF structure and the scheme provided by the invention can greatly improve the spectrum efficiency compared with the traditional symbol-level ABF no matter the Rayleigh fading channel or the millimeter wave channel.
Therefore, in the technical scheme of the embodiment of the invention, the signal passes through NtBefore the signal transmitting antenna carries out wireless transmission, the signals firstly pass through N in paralleltThe signal transmitting filter performs subcarrier level analog beam forming, so that the ABF performance of different subcarrier channels can be ensured, and the spectral efficiency of the system is effectively improved.
The signal transmission filter is determined according to the beamforming vector selected for each subcarrier by the respective channel characteristic, that is, the signal transmission filter designed after selecting the optimal ABF vector for each subcarrier by the respective channel characteristic can ensure the ABF performance of different subcarrier channels to the maximum extent.
Those skilled in the art will appreciate that the present invention includes apparatus directed to performing one or more of the operations described in the present application. These devices may be specially designed and manufactured for the required purposes, or they may comprise known devices in general-purpose computers. These devices have stored therein computer programs that are selectively activated or reconfigured. Such a computer program may be stored in a device (e.g., computer) readable medium, including, but not limited to, any type of disk including floppy disks, hard disks, optical disks, CD-ROMs, and magnetic-optical disks, ROMs (Read-Only memories), RAMs (Random Access memories), EPROMs (Erasable programmable Read-Only memories), EEPROMs (Electrically Erasable programmable Read-Only memories), flash memories, magnetic cards, or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a bus. That is, a readable medium includes any medium that stores or transmits information in a form readable by a device (e.g., a computer).
It will be understood by those within the art that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. Those skilled in the art will appreciate that the computer program instructions may be implemented by a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the features specified in the block or blocks of the block diagrams and/or flowchart illustrations of the present disclosure.
Those of skill in the art will appreciate that various operations, methods, steps in the processes, acts, or solutions discussed in the present application may be alternated, modified, combined, or deleted. Further, various operations, methods, steps in the flows, which have been discussed in the present application, may be interchanged, modified, rearranged, decomposed, combined, or eliminated. Further, steps, measures, schemes in the various operations, methods, procedures disclosed in the prior art and the present invention can also be alternated, changed, rearranged, decomposed, combined, or deleted.
Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the invention, also features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, substitutions, improvements and the like that may be made without departing from the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A signal transmission method based on a subcarrier-level analog beamformer, comprising:
the signal p is sequentially subjected to a serial-to-parallel converter, a Fourier inverse converter, a cyclic prefix adding device and a parallel-to-serial converter to obtain a time domain sampling point sequence of a sending end
Will be provided withPassing N simultaneously in paralleltA signal transmission filter for realizing subcarrier-level analog beam forming;
the output of each signal transmission filter is respectively divided into NtThe signal transmitting antennas perform wireless transmission.
2. The method of claim 1, further comprising:
by NrA signal receiving antenna receives the signal and converts NrThe signals received by the antennas respectively pass through NrAfter receiving the filter, the signals are superposed and combined into a signal r;
and sequentially passing the signal r through a serial-to-parallel converter, a Fourier converter, a cyclic prefix remover and a parallel-to-serial converter to obtain a receiving end frequency domain sampling point sequence p'.
3. The method according to claim 1 or 2, wherein the signal transmission filter is determined from the beamforming vector selected for each subcarrier according to its respective channel characteristic:
determining the optimal beam forming vector of a transmitting end aiming at the subcarrier transmitted by the signal transmitting antenna connected with each signal transmitting filter;
and determining a time domain beamforming filter as the signal sending filter according to the optimal beamforming vector of the sending end.
4. The method according to claim 3, wherein the determining a time-domain beamforming filter according to the optimal beamforming vector at the transmitting end specifically comprises:
obtaining N according to the following expressions of four and fivetA time domain beam forming filter of
Wherein BETAkK is the best beamforming vector on the kth subcarrier, K being 1, 2. K is the number of subcarriers, F-1An IFFT is represented.
5. The method according to claim 1 or 2, wherein the signal reception filter is determined from the beamforming combining vector selected for each subcarrier according to its respective channel characteristic:
determining the optimal beam combination vector of a receiving end aiming at the sub-carrier received by the signal receiving antenna connected with each signal receiving filter;
and determining a time domain beam combination filter as the signal receiving filter according to the optimal beam combination vector of the receiving end.
6. The method according to claim 5, wherein the determining a time-domain beam combination filter according to the optimal beam combination vector of the receiving end specifically comprises:
obtaining N according to the following expressions six and sevenrA time domain beam forming filter of
Wherein D iskCombining vectors for the best beam on the kth sub-carrier, K being 1, 2.K is the number of subcarriers, F-1An IFFT is represented.
7. A signal transmission apparatus based on a subcarrier-level analog beamformer, comprising: a signal transmitting device located at the base station side; wherein the signal transmission device includes:
a serial-to-parallel converter, an inverse Fourier converter, a cyclic prefix adding device and a parallel-to-serial converter which are connected in series in sequence and used for converting the signal p into a time domain sampling point sequence of a sending end
NtA signal transmitting filter connected with the output end of the parallel-serial converter for transmitting the signalsPerforming N simultaneously in paralleltFiltering the wave to realize analog beam forming;
Ntsignal transmitting antennas respectively connected to NtAnd signal transmission filters for wirelessly transmitting the output signals of the signal transmission filters.
8. The apparatus of claim 7, wherein N istEach signal receiving filter isThe method is obtained according to the following expressions four and five:
wherein BETAkK is the best beamforming vector on the kth subcarrier, K being 1, 2. K isNumber of subcarriers, F-1An IFFT is represented.
9. A signal transmission apparatus based on a subcarrier-level analog beamformer, comprising: a signal receiving device located at a user side; wherein the signal transmission device includes:
Nra signal receiving antenna for receiving a wireless signal;
Nra signal receiving filter, the input end of each signal receiving filter is respectively connected with an antenna, and the output ends of the signal receiving filters are mutually connected and used for connecting NrThe signals received by the antennas respectively pass through NrFiltering the signal by a signal receiving filter, and then superposing and combining the signal into a signal r;
the device comprises a serial-to-parallel converter, a Fourier converter, a cyclic prefix remover and a parallel-to-serial converter which are sequentially connected in series and used for converting a signal r into a receiving end frequency domain sampling point sequence p'.
10. The apparatus of claim 9, wherein N isrA signal receiving filter ofThe method is obtained according to the following expressions six and seven:
wherein D iskCombining vectors for the best beam on the kth sub-carrier, K being 1, 2. K is the number of subcarriers, F-1An IFFT is represented.
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