CN106533526A - On-off analog beamforming system constrained by independent power - Google Patents

Abstract

The present invention provides a switch analog beamforming system subject to independent power constraints, including: a radio frequency chain at a transmitting end, a radio frequency switch component and a radio frequency chain at a receiving end, the radio frequency chain at the transmitting end is connected to the input end of the radio frequency switch component, the The output terminal of the radio frequency switch component is connected with the radio frequency chain of the receiving end; wherein, the radio frequency switch component includes N transmitting radio frequency switches and N transmitting radio frequency antennas, and the radio frequency switch component selects a radio frequency switch as a receiving radio frequency switch to Realize point-to-point transmission, and control the radio frequency switch state of the radio frequency switch component according to the channel information to maximize the receiving signal-to-noise ratio; the transmit power of each transmit radio frequency antenna of the radio frequency switch component is individually constrained by the transmit power of the transmitter. The present invention only uses an analog switch to realize switching analog beamforming gain, all selected radio frequency antennas are directly connected to a corresponding radio frequency chain, and can realize full multiplexing gain and full diversity gain.

Description

A Switching Analog Beamforming System Subject to Independent Power Constraints

technical field

The present invention relates to an analog beamforming system, in particular to a switching analog beamforming system subject to independent power constraints.

Background technique

Among the potential technologies for future 5G, massive multiple-input multiple-output (MIMO) has been shown to be able to increase the spectral efficiency of a system several times. A typical massive MIMO system is cellular communication, where a base station (BS) is equipped with a large number of antennas to serve mobile users. Furthermore, with the development of high-frequency communication (especially above 30 GHz), a large number of antennas is not only possible, but also has to compensate for the small array gain due to the compact antenna size.

Digital beamforming is a well-developed technology in MIMO systems, which has the advantages of flexibility, adaptability and performance optimization. However, digital beamforming is too expensive and power-hungry to be used in massive MIMO because each antenna is connected to an expensive RF (radio frequency) chain, usually consisting of power amplifiers, analog-to-digital or digital-to-analog converters, analog-to-analog devices and mixers etc.

With the development of high-frequency communication, especially the development of 60 GHz, due to the size of compact antennas, a large number of antennas is not only possible but must be used to compensate for the small array gain. In order to save the number of RF chains in digital beamforming (the cost and power consumption of RF chains are very high), the method of adopting phase shifters and power amplifiers in the RF domain to the beamforming operation in the analog domain has regained more attention . The design of analog RF architectures and beamforming algorithms has been thoroughly studied in several publications. These works show that the performance drawbacks of using analog beamforming are justified by reducing the hardware overhead cost compared to conventional architectures using digital beamforming. While analog beamforming has power and cost advantages, implementing it can be a huge challenge and reliability issue when designing RF hardware, especially for millimeter-wave (mm-wave) carrier signals. In the prior art, some simple analog beamforming structures have also been proposed to reduce the complexity of the hardware, but this is achieved at the cost of reducing performance. Like phase shifters, RF power amplifiers with variable gain are also necessary, making it challenging and expensive to implement analog beamforming.

Contents of the invention

The technical problem to be solved by the present invention is to provide a switching analog beamforming system with reasonable cost control, small size, fast speed, linear bandwidth and high frequency that is constrained by independent power.

In this regard, the present invention provides a switch analog beamforming system subject to independent power constraints, including: a radio frequency chain at a transmitting end, a radio frequency switch component and a radio frequency chain at a receiving end, and the radio frequency chain at the transmitting end is connected to the input end of the radio frequency switch component , the output end of the radio frequency switch assembly is connected to the radio frequency chain at the receiving end; wherein, the radio frequency switch assembly includes N transmit radio frequency switches and N transmit radio frequency antennas corresponding to the transmit radio frequency switches, N is the transmit radio frequency The number of antennas, N is a natural number; the radio frequency switch component selects a radio frequency switch as the receiving radio frequency switch to realize point-to-point transmission between the transmitting radio frequency switch and the receiving radio frequency switch, and between the transmitting radio frequency switch and the receiving radio frequency switch The channel of the channel has an independent distributed variable of Gaussian distribution, and the switch analog beamforming system controls the RF switch state of the RF switch assembly according to the channel information to maximize the receiving signal-to-noise ratio; the transmit power of each transmit RF antenna of the RF switch assembly Constrained solely by the transmit power of the transmitter.

A further improvement of the present invention is that the input terminals of the N transmitting radio frequency switches are all connected to the output terminals of the transmitting radio frequency chain, and the output terminals of each transmitting radio frequency switch are respectively connected to a transmitting terminal corresponding to one of them. radio frequency antenna.

A further improvement of the present invention is that the radio frequency switch assembly further includes a receiving radio frequency switch and a receiving radio frequency antenna corresponding to the receiving radio frequency switch, and the input end of the receiving radio frequency switch is connected to a receiving radio frequency antenna corresponding to one of them, so The output terminals of the receiving radio frequency switch are all connected to the input terminals of the radio frequency chain of the receiving terminal.

A further improvement of the present invention is that, in the radio frequency chain at the transmitting end, the transmitter is connected to the input end of the shunt through a power amplifier, and the output end of the shunt is connected to the transmitting radio frequency switch of the radio frequency switch assembly.

A further improvement of the present invention is that in the radio frequency chain at the receiving end, the receiver is connected to the output end of the combiner through the low noise amplifier, and the input end of the combiner is connected to the receiving radio frequency switch of the radio frequency switch assembly.

A further improvement of the present invention is that the baseband received signal system model of the receiver is The signal-to-noise ratio received by the receiver is Among them, P _o is the transmitting power of the transmitter; h _j is the channel coefficient between the jth transmitting radio frequency antenna and the receiving radio frequency antenna, and h _j , 0≤j≤N all obey the complex Gaussian distribution CN(0,1) The independent and identically distributed variables of ; x is the baseband signal of the transmitter; n～CN(0,σ ² ) represents the Gaussian white noise of the receiver; T is the set of transmitting radio frequency antennas; |∑ _j∈T h _j | ² is Receiver signal power.

A further improvement of the present invention is that each transmitting radio frequency antenna transmits a radio frequency signal with its maximum transmission power.

A further improvement of the present invention is that the switch analog beamforming system controls the RF switch state of the RF switch assembly according to channel information to maximize the receiving signal-to-noise ratio, including the following steps:

Step S1, according to the channel coefficients of the N transmitting radio frequency antennas, draw N orthogonal vertical lines for the N channel coefficients, and divide the complex plane composed of the N transmitting radio frequency antennas into a total of 2N sectors;

Step S2, for each sector, determine a corresponding set V _K ;

Step S3, for the first set V ₁ , calculate the sum of all channel coefficients in it

Step S4, calculate the sum of all the channel coefficients in turn for the following sets

k(k=2,...,2N);

Step S5, for all f _k , select the one with the largest absolute value; use the set V _K corresponding to the f _k with the largest absolute value as the set T of transmitting radio frequency antennas.

A further improvement of the present invention is that in the step S2, if the projection of the i-th channel coefficient h _i in the sector k is a positive number, then h _i ∈ V _k ; otherwise

A further improvement of the present invention is that in the step S1, two-dimensional complex planes of N channel coefficients h _j (j=1; 2; ...; N) are drawn, and the horizontal axis and the vertical axis correspond to the real part and the imaginary part respectively Department; then for each channel coefficient h _j draw its orthogonal line through the origin to get 2N sectors.

Compared with the prior art, the beneficial effect of the present invention is that: based on the channel state information, each of the multiple transmitting radio frequency antennas is switched on or off to implement beamforming, which can significantly reduce the number of times used in traditional analog beamforming systems. high cost, high power consumption and bulky analog phase shifter, the present invention only uses a simple analog switch to realize switching analog beamforming gain, and all selected radio frequency antennas are directly connected to a corresponding radio frequency chain without other radio frequency chains Or any preprocessing equipment such as a phase shifter, the effect of the switching analog beamforming system of the present invention is simply realized by selecting a part of the radio frequency antenna, and can realize full multiplexing gain and full diversity gain.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of an embodiment of the present invention;

Fig. 2 is a schematic diagram of the principle of a digital beamforming switch in the prior art;

FIG. 3 is a schematic diagram of the principle of an analog beamforming switch in the prior art;

FIG. 4 is a schematic diagram of the principle of antenna selection in the prior art;

Fig. 5 is a schematic diagram of a detailed system model of an embodiment of the present invention;

Fig. 6 is a schematic diagram of the principle of dividing the complex plane into 8 sectors by 4 channel coefficients in an embodiment of the present invention;

FIG. 7 is a schematic diagram of simulating the normalized signal-to-noise ratio of a receiver by increasing the number of antennas according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a simulation of obtaining the average achievable rate of the receiver by averaging the instantaneous rate achieved by each channel in an embodiment of the present invention;

Fig. 9 is a schematic diagram of a probability simulation of a receiver whose signal-to-noise ratio is smaller than a given threshold according to an embodiment of the present invention.

detailed description

The preferred embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, this example provides a switch analog beamforming system subject to independent power constraints, including: a transmitter radio frequency chain, a radio frequency switch component and a receiver radio frequency chain, the input of the transmitter radio frequency chain and the radio frequency switch component terminals, and the output end of the radio frequency switch component is connected to the receiving end radio frequency chain; wherein, the radio frequency switch component includes N transmitting radio frequency switches and N transmitting radio frequency antennas corresponding to the transmitting radio frequency switches, N For the number of transmitting radio frequency antennas, N is a natural number; the radio frequency switch component selects a radio frequency switch as the receiving radio frequency switch to realize point-to-point transmission between the transmitting radio frequency switch and the receiving radio frequency switch, and the transmitting radio frequency switch and the receiving radio frequency The channel between the switches has an independent distribution variable of Gaussian distribution, and the switch analog beamforming system controls the radio frequency switch state of the radio frequency switch assembly according to the channel information to maximize the receiving signal-to-noise ratio; each transmitting radio frequency antenna of the radio frequency switch assembly The transmit power of is constrained solely by the transmit power of the transmitter.

As shown in Figure 1, the input terminals of the N transmitting radio frequency switches are all connected to the output terminals of the transmitting terminal radio frequency chain, and the output terminals of each transmitting radio frequency switch are respectively connected to a corresponding transmitting radio frequency Antenna; the radio frequency switch assembly also includes a receiving radio frequency switch and a receiving radio frequency antenna corresponding to the receiving radio frequency switch, the input end of the receiving radio frequency switch is connected to a corresponding receiving radio frequency antenna, the receiving radio frequency switch The output terminals are all connected to the input terminals of the radio frequency chain at the receiving end.

Different from the traditional AF structure, this example proposes to use a simple analog switch such as a radio frequency switch to replace the bulky and expensive phase shifter to complete the realization of switch analog beamforming. This example is called OABF, which is the The on-off analog beamforming system based on front antenna power constraints is referred to as OABF, that is, On-off Analog Beamforming. In fact, RF switches in the market have been widely used in wireless transceivers, and they have very attractive properties, such as cheap, small size, fast speed, almost no power consumption, linear bandwidth, and high frequency. In particular, in this example, the received SNR is maximized by controlling the switch state of the radio frequency antenna according to the channel information, and SNR is a signal-to-noise ratio. Finding the optimal subset of RF antennas looks like a combinatorial optimization problem, also known as NP-hard (non-deterministic polynomial problem).

It is worth mentioning that this example utilizes a simultaneous quadrature matching pursuit strategy to solve a specific switched analog beamforming, the difficulty of which appears to grow exponentially with the number of antennas. But counterintuitively, we find that there are only linear complexity and polynomial complexity to determine the switching state of each RF antenna. More importantly, this example proves theoretically that the switch analog beamforming system (OABF) described in this example can achieve full multiplexing gain and full diversity gain, based on the switch analog beamforming system described in this example controls the radio frequency according to the channel information The step of switching the RF switching state of the components to maximize the received signal-to-noise ratio. The radio frequency antenna includes a transmitting radio frequency antenna and a receiving radio frequency antenna.

The switched analog beamforming described in this example is fundamentally different from the well-studied subset antenna selection scheme, where the best k antennas are selected from a total of N antennas. In traditional antenna selection, each selected antenna is connected by an RF chain (or an analog shifter) to achieve coherent combining. Therefore, k is usually determined by the number of RF chains available, and the beamforming effect comes from the signal processing of the RF chains (or phase shifters). Whereas in the switched analog beamforming system (OABF) described in this example, all selected RF antennas are directly connected to one RF chain without any pre-processing equipment, i.e. without any pre-processing equipment such as other RF chains and phase shifters, The switch simulates the effect of a beamforming system simply by selecting a portion of the RF antenna.

The structure of the OABF is introduced as follows: for comparison, three typical existing multi-antenna beamforming structures, digital beamforming, phase-aligned analog beamforming and antenna selection in the prior art are firstly reviewed.

In most wireless systems today, fully optimal beamforming is implemented in the digital domain, where each antenna is followed by an RF chain in order to convert it to a baseband digital signal, not only the amplitude but also the phase of the signal. The situation in the digital domain is adjusted accordingly, and its structure diagram is shown in Figure 2; in communications with high frequency and wide bandwidth, the cost of the radio frequency chain, especially the price and space cost, is much higher than that of the antenna.

For millimeter wave communication, the size of the antenna and the gain of the antenna are greatly reduced; when the antenna gain is to be maintained in the low-frequency system, the beamforming method requires a large number of antennas to transmit. However, a large number of antennas will definitely increase the cost of the RF chain in a digital beamforming system significantly. Therefore, other beamforming schemes have been proposed to save the RF chain and maintain multi-antenna gain.

A typical scheme is analog beamforming, which satisfies the operation of beamforming in the analog domain, as shown in Figure 3, in the analog beamforming, each antenna is connected with an analog phase shifter, so that in After the transmitting end is separated by the RF chain (or the RF chain can be satisfied before the receiving end is combined), the beamforming coefficient of the analog RF signal can be formed. Due to the constraints of the analog phase shifters, generally only the phase of each antenna signal is controlled.

Analog phase shifters, especially those with wide bandwidth and high frequency capability, are also very expensive and bulky; the less complex/cost solution is antenna selection, where only one antenna is connected to the RF chain , as shown in Figure 4, the antenna selection scheme can also obtain full diversity gain. However, its array gain is only Much smaller than the full array gain.

In the comparison of analog beamforming versus antenna selection, this example uses all RF antennas with phase-aligned signals, while RF antenna selection uses only one antenna without any further signal processing. In this example, a new low-complexity switching analog beamforming system structure between antenna selection and analog beamforming is adopted, and the selected transmit RF antenna subset for transmitting signals does not require any RF signal processing , while the other antennas are not connected, as shown in Figure 1. In this example, the radio frequency switch corresponding to the selected radio frequency antenna is always on and the others are off. Therefore, this example calls it a front antenna power-constrained switch analog beamforming system, or OABF for short.

In OABF, a subset with better channel conditions and similar phases among the N transmitting radio frequency antennas is selected to be connected to the radio frequency chain. If the subset of bases is restricted to 1, OABF degenerates into the antenna selection scheme shown in Figure 3. On the other hand, if the analog coefficients of a switched analog beamforming system are constrained to either 0 or 1, then it is an OABF as described in this example.

This example is equivalent to the baseband system model, and a simple system model and corresponding symbols are firstly introduced here. Without loss of generality, this example considers a point-to-point transmission system in which the transmitter has N transmitting radio frequency antennas and one receiving radio frequency antenna at the receiver. The extension to the case of multiple receive RF antennas is also straightforward. We assume that there is only one data flow, so there is one RF chain per side. The channel between the jth transmit antenna and the receive RF antenna is denoted h _j , which is fully predicted by the transmitter through some feedback scheme or reciprocity of the channel, and thus is completely known to the transmitter. We further assume that all h _j , 0≤j≤N are independent and identically distributed variables obeying the complex Gaussian distribution CN(0,1); the channel coefficients remain constant during a packet transmission and are independent between different packet transmissions Change. This channel model is validated and used for an indoor mm-wave communication scenario where a portable terminal with an omni-directional antenna moves at walking speed.

A more detailed OABF transmission structure is shown in Figure 5. In this example, _Pj is used to represent the transmit power of the jth antenna; at the transmitter, some transmit RF antennas form a set T and are used for transmission and transmission. Then, the baseband received signal y of the receiver is, st=1 if h _{i ∈} T, else I _i =0.

Among them, n～CN(0,σ ² ) represents the Gaussian white noise of the receiver; I _i is the indicator variable, and T is the set of transmitting radio frequency antennas, that is, the set {h ₁ ,h ₂ …h _N }; through experience, choose The optimal set T to optimize the receive SNR is a combinatorial optimization problem and has exponential complexity with respect to the number of antennas.

As shown in Figure 5, in the radio frequency chain of the transmitting end, the transmitter is connected to the input end of the shunt through a power amplifier, and the output end of the shunt is connected to the transmitting radio frequency switch of the radio frequency switch assembly; the receiving end In the radio frequency chain, the receiver is connected to the output terminal of the combiner through the low noise amplifier, and the input terminal of the combiner is connected to the receiving radio frequency switch of the radio frequency switch assembly.

In this example, each antenna at the transmitting end has an independent power constraint, that is, the transmit power of each transmitting RF antenna is determined by the individual power constraint of the transmitter ie, P _j ≤ P _o , In this formula, it means that for each transmitting radio frequency antenna j, its transmitting power is less than the given maximum power Po; for performance comparison, this example mainly analyzes two basic progressive gains to realize transmission beamforming: array gain and diversity gain. Array gain refers to the increase in the average output SNR over the input signal-to-noise ratio SNR for a total of N transmit RF antennas; diversity gain refers to the reduction ratio of the average value of the bit error rate before fading ; The increase of the input SNR with N transmit RF antennas with respect to the average output SNR is called the array gain, fading The average decay rate with respect to the bit error rate _Pe .

We consider the case where the transmit power of each transmit RF antenna is individually limited by the transmit power _Po of the transmitter, and there is no constraint on the total transmit power. This assumption results from the fact that each antenna in a practically realized transmitter is driven by a separate power amplifier, which only works properly when its transmit power is below a preset threshold. In current analog beamforming systems, separate transmit power constraints are sometimes more relevant than concatenated power constraints.

Then, each transmitting radio frequency antenna all transmits a radio frequency signal with its maximum transmission power, and the baseband receiving signal system model of the receiver is Therefore, the signal-to-noise ratio received by the receiver is Among them, P _o is the transmitting power of the transmitter; h _j is the channel coefficient between the jth transmitting radio frequency antenna and the receiving radio frequency antenna, and h _j , 0≤j≤N all obey the complex Gaussian distribution CN(0,1) The independent and identically distributed variables of ; x is the baseband signal of the transmitter; n～CN(0,σ ² ) represents the Gaussian white noise of the receiver; T is the set of transmitting radio frequency antennas; |∑ _j∈T h _j | ² is Receiver signal power.

In this example, an optimal and linear complexity algorithm OABF-s is first introduced to determine the set T in order to maximize the signal-to-noise SNR. Afterwards, we demonstrate the full-diversity gain and full-array gain of OABF-s by providing a suboptimal bridge algorithm; details are described below.

The switch analog beamforming system described in this example controls the RF switch state of the RF switch component according to the channel information to maximize the received signal-to-noise ratio, including the following steps:

Step S1, according to the channel coefficients of the N transmitting radio frequency antennas, draw N orthogonal vertical lines for the N channel coefficients, and divide the complex plane composed of the N transmitting radio frequency antennas into a total of 2N sectors;

Step S2, for each sector k, determine a corresponding set V _k , h _i ∈ V _k means if the projection of h _i in sector k is a positive number;

Step S3, for the first set V ₁ , calculate the sum of all channel coefficients in it

Step S4, calculate the sum of all the channel coefficients in turn for the following sets

k(k=2,...,2N);

Step S5, for all f _k , select the one with the largest absolute value; use the set V _K corresponding to the f _k with the largest absolute value as the set T of transmitting radio frequency antennas.

In step S2 described in this example, if the projection of the i-th channel coefficient h _i in sector k is a positive number, then h _i ∈ V _k ; otherwise As shown in Figure 6, in the step S1 described in this example, the two-dimensional complex plane of N channel coefficients h _j (j=1; 2; ...; N) is drawn, and its horizontal axis and vertical axis correspond to the real part and The imaginary part; then for each channel coefficient h _j draw its orthogonal line through the origin, resulting in 2N sectors.

Next, this example presents some simulated numerical results to show the performance of the proposed switching analog beamforming system. In the simulations, the noise variance at the receiver side is normalized to unity. With the transmit power of each transmit radio antenna constrained by the individual power of the transmitter, the transmit power of each transmit radio antenna is set to a fixed value P _o . Each channel coefficient is randomly generated complex Gaussian distribution n~CN(0,1). For consistency purposes, this example still refers to the equal-gain scheme as the best-of-the-art scheme.

As shown in Fig. 7, Benin simulates the normalized signal-to-noise ratio SNR at the receiver by increasing the number of antennas, which is defined as the receiving Divide by transmit power P _o |T| in order to show array gain for different schemes. As can be seen from Fig. 7, the normalized SNR of the switching module beamforming system (OABF) and the best scheme of the prior art in this example increases linearly with the number of antennas, that is, the full array gain is obtained; on the other hand, the antenna selection The normalized SNR of the regimens increases logarithmically. In Figure 7, the ordinate refers to Normalized Received SNR refers to the normalized signal-to-noise ratio; For example, the switching module beamforming system (OABF); Optimal Scheme refers to the optimal scheme of the prior art; AntennaSelection refers to antenna selection.

As shown in Figure 8, the average achievable rate at the receiver is obtained by averaging the instantaneous rate achieved for each channel; it can be seen that the rates of all three schemes increase with the number of antennas, while the There is a constant upper bound on the gap between the switch module beamforming system (OABF) described above and the state-of-the-art best solution. In Figure 8, the Achievable rate on the ordinate refers to the reachability rate; the Number of Antennas on the abscissa refers to the quantity in plural form, which is used to represent the increase in the number of antennas; OABF refers to the beamforming of the switch module described in this example System (OABF); OptimalScheme refers to the optimal scheme of the existing technology; Antenna Selection refers to antenna selection.

As shown in Figure 9, the outage probability is simulated, that is, the probability that the accurate reception SNR is less than a given threshold; in Figure 9, it can be clearly seen that the number of antennas is 1, 2, 3 when N=1, 2, 3 Diversity order. When N=1, the switching module beamforming system (OABF) described in this example has the same performance as the optimal solution; when N=2, there is a gap of about 2.5dB, and when N=3, the gap increases to 4dB. In Fig. 9, the Outage Pribability of the ordinate refers to the outage probability; the SNR (dB) of the abscissa refers to the signal-to-noise ratio; OABF, N=1 refers to that the switch module beamforming system (OABF) transmits radio frequency The outage probability simulation curve when the number of antennas N=1; Optimal Scheme, N=1 refers to the outage probability simulation curve of the best scheme of the prior art when the number of radio frequency antennas N=1; in the same way, OABF, N=2 refers to the outage probability simulation curve of the switch module beamforming system (OABF) when the number of transmitting radio frequency antennas is N=2; Optimal Scheme, N=2 refers to the optimal scheme of the prior art when transmitting The outage probability simulation curve when the number of radio frequency antennas N=2; OABF, N=3 refers to the outage probability simulation curve of the switch module beamforming system (OABF) when the number of radio frequency antennas N=3; Optimal Scheme , N=3 refers to the outage probability simulation curve of the best solution in the prior art when the number of transmitting radio frequency antennas is N=3,

That is, this example proposes a new switch analog beamforming system, On-Off Analog Beamforming (OABF), which uses only simple analog switches to achieve beamforming gain. In order to determine the state of each switch with given channel information, this example proposes an optimal algorithm that the switch analog beamforming system controls the RF switch state of the RF switch assembly according to the channel information to maximize the received signal-to-noise ratio to maximize the receive SNR under the individual power constraints of each transmit RF antenna. Using polynomial complexity, the switch-block beamforming system (OABF) described in this example can achieve full diversity gain and full array gain. More specifically, the achievable rate gap between the optimal solution (equal-gain beamforming) and the switch-block beamforming system (OABF) described in this example is constant at 3.3 bits/symbol, regardless of the number of RF antennas and SNR.

The switching analog beamforming system described in this example is not compatible with other analog beamforming schemes to form a new hybrid architecture. Other beamforming systems, such as radar, can also use the switch-on-block beamforming system (OABF) described in this example to reduce system cost.

In summary, this example, based on channel state information, each of the multiple transmit RF antennas is switched on or off to achieve beamforming, which can significantly reduce the costly, high power consumption and bulk of conventional analog beamforming systems. Bulky analog phase shifter, the invention only uses simple analog switches to switch analog beamforming gain, all selected RF antennas are directly connected to one corresponding RF chain without any preprocessing equipment such as other RF chains or phase shifters , the effect of the switching analog beamforming system in the present invention is realized simply by selecting a part of radio frequency antennas, and can realize complete multiplexing gain and full diversity gain.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (10)

1. A switch analog beamforming system subject to independent power constraints, characterized in that it comprises: a transmitter radio frequency chain, a radio frequency switch component and a receiver radio frequency chain, the transmitter radio frequency chain is connected to the input of the radio frequency switch component , the output end of the radio frequency switch assembly is connected to the radio frequency chain at the receiving end; wherein, the radio frequency switch assembly includes N transmit radio frequency switches and N transmit radio frequency antennas corresponding to the transmit radio frequency switches, N is the transmit radio frequency The number of antennas, N is a natural number; the radio frequency switch component selects a radio frequency switch as the receiving radio frequency switch to realize point-to-point transmission between the transmitting radio frequency switch and the receiving radio frequency switch, and between the transmitting radio frequency switch and the receiving radio frequency switch The channel of the channel has an independent distributed variable of Gaussian distribution, and the switch analog beamforming system controls the RF switch state of the RF switch assembly according to the channel information to maximize the receiving signal-to-noise ratio; the transmit power of each transmit RF antenna of the RF switch assembly Constrained solely by the transmit power of the transmitter. 2. The switch analog beamforming system subject to independent power constraints according to claim 1, wherein the input ends of the N transmitting radio frequency switches are all connected with the output ends of the transmitting end radio frequency chains, each The output ends of the transmitting radio frequency switches are respectively connected to one corresponding transmitting radio frequency antenna. 3. The switch analog beamforming system subject to independent power constraints according to claim 1 or 2, wherein the radio frequency switch component also includes a receiving radio frequency switch and a receiving radio frequency antenna corresponding to the receiving radio frequency switch, the The input ends of the receiving radio frequency switches are connected to the corresponding receiving radio frequency antennas, and the output ends of the receiving radio frequency switches are connected to the input ends of the receiving end radio frequency chains. 4. The switch analog beamforming system subject to independent power constraints according to claim 3, wherein, in the radio frequency chain at the transmitting end, the transmitter is connected to the input end of the shunt through a power amplifier, and the shunt's The output end is connected to the transmitting radio frequency switch of the radio frequency switch assembly. 5. The switch analog beamforming system subject to independent power constraints according to claim 4, wherein in the radio frequency chain at the receiving end, the receiver is connected to the output end of the combiner through a low-noise amplifier, and the combiner The input terminal of is connected to the receiving radio frequency switch of the radio frequency switch component. 6. The switch analog beamforming system subject to independent power constraints according to claim 5, wherein the baseband receiving signal system model of the receiver is The signal-to-noise ratio received by the receiver is Among them, P _o is the transmitting power of the transmitter; h _j is the channel coefficient between the jth transmitting radio frequency antenna and the receiving radio frequency antenna, and h _j , 0≤j≤N all obey the complex Gaussian distribution CN(0,1) The independent and identically distributed variables of ; x is the baseband signal of the transmitter; n～CN(0,σ ² ) represents the Gaussian white noise of the receiver; T is the set of transmitting radio frequency antennas; |∑ _j∈T h _j | ² is Receiver signal power. 7. The independently power-constrained switching analog beamforming system according to claim 6, wherein each transmit radio frequency antenna transmits radio frequency signals with its maximum transmit power. 8. The switch analog beamforming system subject to independent power constraints according to claim 6, wherein the switch analog beamforming system controls the radio frequency switch state of the radio frequency switch assembly according to channel information to maximize the receiving signal-to-noise ratio The following steps: Step S1, according to the channel coefficients of the N transmitting radio frequency antennas, draw N orthogonal vertical lines for the N channel coefficients, and divide the complex plane composed of the N transmitting radio frequency antennas into a total of 2N sectors; Step S2, for each sector, determine a corresponding set V _K ; Step S3, for the first set V ₁ , calculate the sum of all channel coefficients in it Step S4, calculate the sum of all the channel coefficients in turn for the following sets Step S5, for all f _k , select the one with the largest absolute value; use the set V _K corresponding to the f _k with the largest absolute value as the set T of transmitting radio frequency antennas. 9. The switching analog beamforming system subject to independent power constraints according to claim 8, characterized in that, in the step S2, if the projection of the ith channel coefficient h _i in sector k is a positive number, then h _i ∈V _k ; otherwise 10. The switch analog beamforming system subject to independent power constraints according to claim 8, characterized in that, in the step S1, the N channel coefficients h _j (j=1; 2; ...; N) are plotted Two-dimensional complex plane, its horizontal axis and vertical axis correspond to the real part and imaginary part respectively; then draw the orthogonal line passing the origin for each channel coefficient h _j to obtain 2N sectors.