WO2019095247A1

WO2019095247A1 - Unmanned aerial vehicle, and power control method thereof

Info

Publication number: WO2019095247A1
Application number: PCT/CN2017/111512
Authority: WO
Inventors: 赵岩; 孙欢
Original assignee: 上海诺基亚贝尔股份有限公司
Priority date: 2017-11-17
Filing date: 2017-11-17
Publication date: 2019-05-23
Also published as: CN111386658A; CN111386658B

Abstract

Embodiments of the disclosure provide an unmanned aerial vehicle, and a power control method thereof. The method comprises: determining a first transmission power of an unmanned aerial vehicle, and a transmission beamforming gain between the unmanned aerial vehicle and a serving base station; decreasing the first transmission power on the basis of the transmission beamforming gain to obtain a second transmission power; and utilizing a beam associated with the transmission beamforming gain to transmit a signal to the serving base station at the second transmission power. The embodiments of the disclosure reduce interference caused by an unmanned aerial vehicle without degrading the performance of the unmanned aerial vehicle and a ground terminal apparatus.

Description

Unmanned aerial vehicle and method for power control thereof

Technical field

Embodiments of the present disclosure generally relate to wireless communication systems including unmanned aerial vehicles, and more particularly, to methods for unmanned aerial vehicles and their power control.

Background technique

In the current 3GPP protocol, new research projects on enhanced support for unmanned aerial vehicles have been approved. The purpose of the research project is to study the capabilities of unmanned aerial vehicles using terrestrial LTE networks. Due to the nature of the propagation channel, as long as the UAV is flying at a low altitude relative to the height of the network device antenna, it behaves like a conventional land terminal device. However, once the UAV is flying above the height of the network device antenna, it will become more visible to multiple network devices due to line-of-sight propagation, so it is more susceptible to interference in the downlink and simultaneously on the uplink. More interference is generated in the link. Such strong interference unmanned aerial vehicles are often referred to as "extremely interfering unmanned aerial vehicles." However, since the support of unmanned aerial vehicles in wireless communication networks is still in the research stage, there is no effective solution to solve the interference problems related to unmanned aerial vehicles.

Summary of the invention

Embodiments of the present disclosure provide an unmanned aerial vehicle, a power control method thereof, and a computer program.

In a first aspect of the present disclosure, a method for power control of an unmanned aerial vehicle is provided. The method includes: determining a first transmit power of the UAV and a transmit beamforming gain of the UAV to the serving base station; reducing the first transmit power to obtain a second transmit power based on the transmit beamforming gain; and utilizing and transmitting The beam associated with the beamforming gain transmits a signal to the serving base station at a second transmit power.

In some embodiments, the method can further include receiving a message from the serving base station indicating the desired received power of the serving base station for the unmanned aerial vehicle; and adjusting the second transmit power based on the expected received power.

In some embodiments, transmitting the signal to the serving base station at the second transmit power using the beam associated with the transmit beamforming gain may include determining that the UAV is the extreme of interference that would produce a greater than a predetermined interference threshold in the uplink. Interfering with the unmanned aerial vehicle; and in response to determining that the unmanned aerial vehicle is an extreme interference unmanned aerial vehicle, transmitting a signal to the serving base station with the second transmit power using a beam associated with the transmit beamforming gain.

In some embodiments, determining that the UAV is an extreme interference unmanned aerial vehicle may include determining that the UAV is in an excessive interference state of the downlink by detecting interference in a downlink of the serving base station and the UAV; The UAV is determined to be an extreme interference with the UAV based on determining that the UAV is in an excessively interfering state of the downlink.

In some embodiments, determining the first transmit power of the UAV may include determining the first transmit power based on a nominal transmit power of the UAV and a path loss of the UAV to the serving base station.

In some embodiments, determining the transmit beamforming gain of the UAV to the serving base station can include determining a transmit beamforming gain based on a receive beamforming gain for the serving base station.

In some embodiments, the method may further comprise: determining a first signal to interference and noise ratio received from the serving base station using receive beamforming for the serving base station; determining a second to receive from the serving base station without using receive beamforming a signal to interference and noise ratio; and determining a receive beamforming gain based on the first signal to interference and noise ratio and the second signal to interference and noise ratio.

In some embodiments, obtaining the second transmit power may include determining the second transmit power such that: at the serving base station, the unmanned aircraft uses the second transmit power and the receive power in the case of the beam The change between the received power in the case where the aircraft uses the first transmit power is lower than a predetermined threshold, and at the non-serving base station, the interference power in the case where the unmanned aircraft uses the second transmit power and the beam is smaller than in the unmanned The interference power in the case where the aircraft uses the first transmission power.

In some embodiments, obtaining the second transmit power can include: receiving a scaling factor from the serving base station; scaling the transmit beamforming gain with a scaling factor; and deriving the scaled transmit beamforming gain using the first transmit power minus Second transmit power.

In some embodiments, the scaling factor may be determined by the higher layer based on the adjustment of the transmit beamforming gain and the difference between the uplink transmit beam and the downlink receive beam.

In a second aspect of the present disclosure, an unmanned aerial vehicle is provided. The UAV includes at least one processor and at least one memory including computer program instructions. At least one memory and computer program instructions are configured, with the at least one processor, to cause the unmanned aircraft to: determine a first transmit power of the unmanned aerial vehicle and a transmit beamforming gain of the unmanned aircraft to the serving base station; Shape gain to reduce the first transmit power to obtain a second transmit power; and transmit a signal to the serving base station at a second transmit power using a beam associated with the transmit beamforming gain.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: receive a message from the serving base station indicating the desired received power of the serving base station for the UAV And adjusting the second transmit power based on the expected received power.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: determine that the UAV is to generate interference that is greater than a predetermined interference threshold in the uplink. Extremely interfering with the unmanned aerial vehicle; and in response to determining that the unmanned aerial vehicle is an extreme interference unmanned aerial vehicle, transmitting a signal to the serving base station at a second transmit power using a beam associated with the transmit beamforming gain.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: determine by detecting interference in the downlink of the serving base station and the UAV The human aircraft is in an excessively disturbing state of the downlink; and the unmanned aerial vehicle is determined to be an extreme interference with the unmanned aerial vehicle based on determining that the unmanned aerial vehicle is in an excessively disturbing state of the downlink.

In some embodiments, the at least one memory and computer program instructions can be further configured to, with the at least one processor, cause the UAV to: based on the nominal transmit power of the UAV and the path loss of the UAV to the serving base station To determine the first transmit power.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: determine a transmit beamforming gain based on a receive beamforming gain for the serving base station.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: determine to use the first signal received from the serving base station using a receive beamforming for the serving base station a noise to noise ratio; determining a second signal to interference and noise ratio that is received from the serving base station without using receive beamforming; and determining a received beamforming gain based on the first signal to interference and noise ratio and the second signal to interference and noise ratio.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: determine the second transmit power such that: at the serving base station, in the UAV The change between the second transmit power and the received power in the case of the beam and the received power in the case where the unmanned aircraft use the first transmit power is below a predetermined threshold, and at the non-serving base station, in the unmanned aerial vehicle The second transmit power and the interference power in the case of the beam are less than the interference power in the case where the unmanned aircraft uses the first transmit power.

In some embodiments, the at least one memory and computer program instructions can be further configured, with the at least one processor, to cause the UAV to: receive a scaling factor from the serving base station; scale the transmit beamforming gain with a scaling factor; The second transmit power is derived using the first transmit power minus the scaled transmit beamforming gain.

In a third aspect of the present disclosure, a computer program product is provided. The computer program product is tangibly stored on a non-transitory computer readable medium and includes machine executable instructions. The machine executable instructions, when executed, cause the machine to perform the steps of the method according to the first aspect.

DRAWINGS

The above and other objects, features and advantages of the embodiments of the present invention will become <RTIgt; In the figures, several embodiments of the present disclosure are shown by way of illustration and not limitation

1 illustrates a wireless communication system including an unmanned aerial vehicle in which an unmanned aerial vehicle does not use beamforming transmit signals, in accordance with an embodiment of the present disclosure.

2 illustrates a wireless communication system including an unmanned aerial vehicle in which an unmanned aerial vehicle uses beamforming to transmit signals, in accordance with an embodiment of the present disclosure.

3 illustrates a wireless communication system including an unmanned aerial vehicle in which an unmanned aerial vehicle reduces transmit power based on a transmit beamforming gain, in accordance with an embodiment of the present disclosure.

FIG. 4 illustrates a method for power control of an unmanned aerial vehicle in accordance with an embodiment of the present disclosure.

FIG. 5 shows a system simulation diagram for verifying the effectiveness of an embodiment of the present disclosure.

Figure 6 shows a block diagram of a device suitable for implementing an embodiment of the present disclosure.

Throughout the drawings, the same or similar reference numerals are used to refer to the same or similar components.

Detailed ways

The principles and spirit of the present disclosure are described below with reference to a few exemplary embodiments illustrated in the drawings. It is to be understood that the specific embodiments are described herein, and are not intended to limit the scope of the disclosure.

As used herein, the term "terminal device" or "terminal" refers to any device having wireless communication capabilities, including but not limited to, a mobile phone, a cellular phone, a smart phone, an unmanned aerial vehicle, a personal digital assistant (PDA), Portable computers, image capture devices such as digital cameras, gaming devices, music storage and playback devices, any portable unit or terminal with wireless communication capabilities, or Internet devices that enable wireless Internet access and browsing, and the like.

Moreover, in the context of the present disclosure, for the sake of simplicity of discussion, the term "terminal device" And "user equipment" can be used interchangeably. Examples of terminal devices in a communication system include, but are not limited to, a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a mobile station (MS), an unmanned aerial vehicle, or an access terminal (AT).

As used herein, the terms "base station (BS)", "network device" and "network node" are used interchangeably and refer to a device capable of providing or hosting a cell, one or more terminals being connectable Enter the community. Examples of BS include, but are not limited to, Node B (NodeB or NB), evolved Node B (eNodeB or eNB), Remote Radio Unit (RRU), Radio Head (RH), Remote Radio Head (RRH), Medium Successive, low power nodes, such as micro base stations, pico base stations, and femto base stations, and the like.

As mentioned above, since the support of unmanned aerial vehicles in wireless communication networks is still in the research stage, there is currently no effective solution to solve the interference problems associated with unmanned aerial vehicles. One possible approach is to limit the maximum transmit power of the UAV, which can be based on parameters such as reference signal received power and path loss threshold. Another possible approach is to force the UAV to reduce its transmit power with a cell-specific power offset. However, these methods have their own shortcomings and deficiencies, and cannot meet the performance requirements of wireless communication systems in many scenarios.

In view of the above or other problems with existing methods for power control of unmanned aerial vehicles, embodiments of the present disclosure provide a power control method and apparatus for an unmanned aerial vehicle that fully utilizes power in the field of wireless communication technology The control mechanism and the beamforming mechanism alleviate the interference problem caused by the introduction of the UAV in the wireless communication system. The basic principles and concepts of the power control method of the embodiment of the present disclosure are first described below with reference to FIGS.

FIG. 1 illustrates a wireless communication system 100 including an unmanned aerial vehicle 130 in which the unmanned aerial vehicle 130 does not use beamforming transmit signals, in accordance with an embodiment of the present disclosure. As shown in FIG. 1, wireless communication system 100 includes network devices 110 and 120 (e.g., eNBs), unmanned aerial vehicles 130, and terminal devices (e.g., user equipment UEs) 140. In the scenario illustrated in FIG. 1, network 110 is a serving base station for UAV 130, and network device 120 is a non-serving base station for UAV 130. The network device 120 is a serving base station of the terminal device 140, and the network device 110 is a non-serving base station for the terminal device 140.

As depicted in FIG. 1, network device 110 has a service range 111 and network device 120 has a service range 121. The unmanned aerial vehicle 130 has a desired signal emission intensity 131 (abbreviation: emission range 131) after being converted by a desired received power. Further, the terminal device 140 has a signal transmission intensity 141. It should be understood that FIG. 1 is not drawn to scale, but for UAV 130 and terminal device 140, to aid understanding, its transmit power can be schematically described using the transmit range.

In addition, a transmission path 150 between the network device 110 and the UAV 130 is also depicted in FIG. 1. The intersection 170 of the transmission path 150 and the transmission range 131 of the UAV 130 may schematically represent the UAV 130 to the serving base station. The transmit power of 110 is 170. Similarly, an interference path 151 between the network device 120 and the unmanned aerial vehicle 130 is depicted in FIG. 1, and the intersection 180 of the interference path 151 and the transmission range 131 of the UAV 130 may schematically represent the unmanned aircraft 130 for non-serving The interference power 180 of the base station 120. As described above, as the flying height of the unmanned aerial vehicle 130 increases, the interference path 151 of the unmanned aerial vehicle 130 and the non-serving base station 120 is likely to be unobstructed, resulting in a large interference power 180.

It is to be understood that the scope of the various embodiments and the scope of Moreover, although it is schematically illustrated in FIG. 1 that the wireless communication system 100 includes only two

network devices

110 and 120, one unmanned aerial vehicle 130, and one terminal device 140, in particular practice, the wireless communication system 100 can include Any number of network devices, terminal devices, and unmanned aerial vehicles.

2 illustrates a wireless communication system 200 including an unmanned aerial vehicle 130 in which an unmanned aerial vehicle 130 uses beamforming to transmit signals, in accordance with an embodiment of the present disclosure. The apparatus and scope that have been described with reference to FIG. 1 are depicted in FIG. 2 with the same reference numerals and will not be described again.

As shown in FIG. 2, in the case where beamforming is used, the UAV 130 no longer has an omnidirectional transmission range 131, but has a directional transmit beam 210 for the serving base station 110. The intersection 270 of the directional transmit beam 210 and the transmission path 150 may schematically represent the transmit power 270 of the unmanned aerial vehicle 130 to the serving base station 110 using beamforming. Similarly, unmanned aerial vehicle 130 typically also has a leak beam 220, It generally has the opposite direction to the directional transmit beam 210. The intersection 280 of the leak beam 220 with the interference path 151 may schematically represent the interference power 280 of the unmanned aerial vehicle 130 to the non-serving base station 120 using beamforming.

As can be seen from FIG. 2, in the case where transmit beamforming is used, the transmit power 170 of the UAV 130 for the serving base station 110 can be increased to the transmit power 270 due to the presence of the transmit beamforming gain. Moreover, since the leak beam 220 is also a directional beam, as the sidelobe beam 220, which typically does not point to the non-serving base station 120, the interference power 180 of the unmanned aerial vehicle 130 to the non-serving base station 120 can be reduced to the interference power 280. Even if the sidelobe beam 220 is accidentally directed to the serving base station 120, it will not exceed the main lobe beam 270.

It is to be understood that the scope of the various embodiments and the scope of the present disclosure are intended to Moreover, although FIG. 2 schematically illustrates that the wireless communication system 200 includes only two

network devices

110 and 120, one unmanned aerial vehicle 130, and one terminal device 140, in particular practice, the wireless communication system 200 can include Any number of network devices, terminal devices, and unmanned aerial vehicles.

Moreover, embodiments of the present disclosure note that it would be advantageous to reduce the transmit power of the UAV 130 to a certain extent based on the use of beamforming by the UAV 130. In this case, although the unmanned aerial vehicle 130 uses the reduced transmit power, since the unmanned aerial vehicle 130 has the gain due to beamforming, the transmit power of the unmanned aerial vehicle 130 for the serving base station 110 can be substantially maintained. The level of beamforming is not used, ie the transmit power 170. On the other hand, in this case, the interference power 280 of the UAV 130 to the non-serving base station 120 can be further reduced, which would be advantageous. This case will be described in detail below in conjunction with FIG.

3 illustrates a wireless communication system 300 including an unmanned aerial vehicle 130 in which the unmanned aerial vehicle 130 reduces transmit power based on the transmit beamforming gain, in accordance with an embodiment of the present disclosure. The devices and ranges that have been described with reference to FIGS. 1 and 2 are depicted in FIG. 3 with the same reference numerals and will not be described again.

As shown in FIG. 3, in the case where beamforming is used and the transmission power is reduced (eg, from the transmission power 131 to the transmission power 330), the unmanned aerial vehicle 130 has The directional transmit beam 310 is directed to the serving base station 110. The intersection 370 of the directional transmit beam 310 and the transmission path 150 may schematically represent the transmit power 370 of the unmanned aerial vehicle 130 to the serving base station 110 in the case of using beamforming and reducing transmit power. Similarly, UAV 130 has a leak beam 320 that generally has an opposite direction to directional transmit beam 310. The intersection 380 of the leak beam 320 with the interference path 151 may schematically represent the interference power 380 of the unmanned aerial vehicle 120 in the case of using the beamforming and reducing the transmit power.

As can be seen from FIG. 3, in the case where the transmit beamforming is used and the transmit power is reduced, the transmit power 370 for the serving base station 110 is smaller than the transmit power 270, although it is less than the transmit power 270 due to the presence of the transmit beamforming gain. The transmit power 170 is substantially the same as in the case where beamforming is not used. Furthermore, since the transmit power of the unmanned aerial vehicle 130 is reduced, the leakage beam 320 becomes smaller than the leak beam 220, and it does not point to the non-serving base station 120, so the interference power 380 of the unmanned aerial vehicle 130 to the non-serving base station 120 can be interfered. The power 280 is further reduced on the basis of.

Furthermore, as can be seen from FIG. 3, embodiments of the present disclosure can ensure that the maximum interference of the UAV 130 to the non-serving base station 120 is no greater than that using the conventional LTE uplink power control method. That is, the beam 320 in FIG. 3 is covered by the range 131. Even though the UAV 130 is only configured with a relatively small number of antennas, embodiments of the present disclosure can greatly reduce the interference ratio or interference area as compared to conventional methods.

It is to be understood that the scope of the various embodiments and the scope of the present disclosure are intended to Moreover, although it is schematically illustrated in FIG. 3 that the wireless communication system 200 includes only two

network devices

110 and 120, one unmanned aerial vehicle 130, and one terminal device 140, in particular practice, the wireless communication system 300 can include Any number of network devices, terminal devices, and unmanned aerial vehicles.

The basic principles and concepts of the embodiments of the present disclosure have been described above in connection with FIGS. 1-3. On this basis, embodiments of the present disclosure propose a method for power control of unmanned aerial vehicle 130. This method is described in detail below in conjunction with FIG.

FIG. 4 illustrates a method 400 for power control of an unmanned aerial vehicle 130 in accordance with an embodiment of the present disclosure. In some embodiments, method 400 can be depicted by Figures 1-3 The unmanned aerial vehicle 130 is executed.

As shown in FIG. 4, at 405, UAV 130 determines its first transmit power 131 and the transmit beamforming gain of UAV 130 to serving base station 110. In some embodiments, UAV 130 may determine first transmit power 131 based on an uplink power control method similar to that in an LTE system. For example, UAV 130 may determine first transmit power 131 based on its nominal transmit power P_0 and its path loss PL_s to serving base station 110.

More specifically, in LTE uplink power control, the setting of the terminal device transmission power P_tx for uplink transmission in a given subframe can be defined by the following formula [1]:

P_tx(i)=min(P_max, P_0+10log10(M(i))+a*PL_s+Delta(i)+f(i), [1] where PL_s represents the uplink path loss of the terminal equipment to the serving base station , can be calculated by subtracting the reference signal received power of the high-level filtering from the reference signal power; a represents an adjustable scaling factor.

In addition, in the formula [1], the items Delta(i) and the item f(i) are related to the closed-loop power control of the terminal device, and the embodiments of the present disclosure mainly focus on the open-loop power control in the LTE standardized power control scheme, Therefore, the above items are not within the scope of the embodiments of the present disclosure. After ignoring the above closed-loop term, the multiple physical resource block allocations represented by the item 10log10(M(i)) are ignored, and the expression used by the terminal device to allocate power to each physical resource block PRB can be simplified to the following formula [ 2]:

PSD_tx=P_0+a*PL_s,[2]

That is, the first transmit power 131 (PSD_tx) of the UAV 130 may be equal to the nominal transmit power P_0 plus the path loss PL_s of the UAV 130 to the serving base station 110 multiplied by the scaling factor a.

In this case, for network device i, the power density it receives can be expressed as the following formula [3]:

PSD_rx_i=PSD_tx-PL_i=P_0+a*PL_s-PL_i,[3]

Where PL_i represents the path loss from the unmanned aerial vehicle 130 to the network device i. If the network device i is the non-serving base station 120, the PSD_rx_i is actually the non-serving base station 120. Interference power. Furthermore, since the terminal device typically uses an omnidirectional antenna in LTE, the beam of the UAV 130 at this time is depicted as a circle 131 in FIGS. 1-3.

Moreover, in some embodiments, UAV 130 may determine a transmit beamforming gain based on a receive beamforming gain for serving base station 110. Specifically, the UAV 130 may calculate the downlink signal to interference and noise ratio (DL) by using a downlink non-beamforming/beamforming decoder by receiving a downlink reference signal (eg, a cell reference signal CRS). SINR). Therefore, the unmanned aerial vehicle 130 can obtain the SINR (ie, SINR_NBF) that does not utilize the beamforming receiver and the SINR (ie, SINR_BF) that utilizes the beamforming receiver.

Due to the line-of-sight propagation characteristics that UAV 130 has as an extreme interference with unmanned aerial vehicles, its uplink transmit beam direction is generally similar to its downlink receive beam direction. Thus, the uplink transmit beamforming gain of UAV 130 can be derived from its downlink receive beamforming gain (ie, the difference between SINR_BF and SINR_NBF).

With continued reference to FIG. 4, at 410, the unmanned aerial vehicle 130 reduces the first transmit power 131 based on the transmit beamforming gain to obtain the second transmit power 330. As discussed above, due to the presence of transmit beamforming gain and directionality using beam 310, UAV 130 is likely to reduce non-serving while maintaining substantially constant transmit power to serving base station 110. The interference power of the base station 120.

Accordingly, the UAV 130 may determine the second transmit power 330 such that at the serving base station 110, the received power 370 in the case of the UAV 130 using the second transmit power 330 and the beam 310 is used with the UAV 130 The change between the received powers 170 in the case of the first transmit power 131 is below a predetermined threshold. In some embodiments, the predetermined threshold may be pre-set based on specific system requirements and technical scenarios. In some embodiments, the received power 370 can be made substantially the same as the received power 170.

Moreover, the unmanned aerial vehicle 130 can determine the second transmit power 330 such that at the non-serving base station 120, the interference power 380 in the case where the unmanned aerial vehicle 130 uses the second transmit power 330 and the beam 310 is less than in the unmanned aerial vehicle 130 The interference power 180 in the case where the first transmission power 131 is used.

In other words, LTE uplink power control can be enhanced in conjunction with beamforming techniques. Since FD-MIMO technology has been widely used, accurate beamforming can be used on both the network device side and the terminal device side. In the case where the transmit beamforming gain from the unmanned aerial vehicle 130 to the serving base station 110 is considered, the above formula [2] can be written as:

PSD_tx_new=P_0+a*PL_s-b*BF_gain_s,[4]

Where BF_gain_s represents the transmit beamforming gain from beamforming and b is an adjustable scaling factor. As indicated above, Equation [4] actually represents a reduction in the first transmit power 131 (PSD_tx) of the UAV 130 based on the compensation of the transmit beamforming gain from the UAV 130 to the serving base station 110. The second transmit power 330 (PSD_tx_new).

In some embodiments, the UAV 130 may receive the scaling factor b from the serving base station 110, scale the transmit beamforming gain BF_gain_s with a scaling factor b, and subtract the scaled transmit beam with the first transmit power 131 (PSD_tx). The shaping gain b*BF_gain_s is derived to derive a second transmit power 330 (PSD_tx_new). In some embodiments, the scaling factor b may be determined by the higher layer based on the adjustment of the transmit beamforming gain and the difference between the uplink transmit beam and the downlink receive beam.

In this case, for network device i, the power density it receives can be expressed as the following formula [5]:

PSD_rx_i_new=PSD_tx_new+BF_gain(azimuth_angle_i)-PL_i;

=P_0+a*PL_s-b*BF_gain_s+BF_gain(azimuth_angle_i)-PL_i;

=P_0+a*PL_s-PL_i-b*BF_gain_s+BF_gain(azimuth_angle_i);

=PSD_rx_i+(BF_gain(azimuth_angle_i)-b*BF_gain_s),[5]

Where BF_gain represents the transmit beamforming gain in different directions under the current beam 310 directed to the serving cell 110.

It can be seen from the formula [5] that if i is equal to s, there is BF_gain(azimuth_angle_s)=BF_gain_s, otherwise BF_gain(azimuth_angle_i)<=BF_gain_s. This means that using the scaling factor b and the beam direction based beamforming gain, it is ensured that the interference power of the non-serving cell 120 is greatly reduced, while the receiving power of the serving base station 110 is reduced. The rate is basically unchanged. That is, if i is not equal to s, then PSD_rx_i_new<<PSD_rx_i, if i is equal to s, PSD_rx_i_new is close to PSD_rx_i.

With continued reference to FIG. 4, at 415, UAV 130 transmits a signal to serving base station 110 at a second transmit power 330 using beam 310 associated with the transmit beamforming gain. In this manner, the UAV 130 can reduce the interference power 180 to the non-serving base station 120 to the interference power 380 while the transmit power 170 to the serving base station 110 is substantially maintained at substantially the same transmit power 370.

In some embodiments, UAV 130 may use beam 310 to transmit a signal at second transmit power 330 in the event that it is determined that it is an "extremely interfering unmanned aerial vehicle" that will generate interference greater than a predetermined interference threshold in the uplink. Otherwise, the first transmit power 131 can be used for transmission. It should be understood that the predetermined interference threshold herein may be preset according to specific design requirements and technical scenarios. In other embodiments, UAV 130 may also perform block 450, block 410, and block 415 in method 400 in sequence after determining that it is "extremely interfering with the unmanned aerial vehicle."

In some embodiments, considering that UAV 130 typically has the characteristics of uplink and downlink extreme interference coexistence, UAV 130 may determine that it is in an excessively interfering state by interference detection in the downlink, such as It is determined that the downlink received signal to noise ratio is below a predetermined threshold. Once the UAV 130 is in an excessively interfering state, it can actively use the uplink interference mitigation method provided by the embodiments of the present disclosure.

Thus, in these embodiments, UAV 130 may determine that UAV 130 is in an excessively interfering state of the downlink by detecting interference in the downlink of serving base station 110 and UAV 130, and based on determining no one The aircraft 130 is in an excessively interfering state of the downlink to determine that the UAV 130 is an extreme interference with the UAV. It should be understood that embodiments of the present disclosure may also employ any other method to determine that the UAV 130 is an "extremely interfering unmanned aerial vehicle."

Moreover, in some embodiments, UAV 130 may also receive a message from serving base station 110 indicating the desired received power of serving base station 110 for UAV 130, and UAV 130 may adjust based on the expected received power. Second Transmit power 330.

In such an embodiment, the uplink open loop power control of the UAV 130 is enhanced by considering the desired received power on the serving base station 110 side. As mentioned above, in prior methods, it is generally of interest to set a cell-specific threshold for the UAV 130 or to apply the same power offset to all UAVs in the cell, ie for all unmanned The aircraft reduces the same transmit power. These methods do not take into account the different interference intensities of each UAV.

To further control the interference of the unmanned aerial vehicle 130 to neighboring cells, in an embodiment of the present disclosure, the serving base station 110 may configure the unmanned aerial vehicle 130 with the desired received power instead of applying the same power offset to all of the unmanned aerial vehicles. Thus, in an embodiment of the present disclosure, UAV 130 may calculate its own uplink second transmit power 330, in addition to considering transmit beamforming gain, nominal transmit power P_0, and path from beam 310. In addition to the loss PL_s, the expected received power of the serving base station 110 is also considered, thereby further improving the interference performance of the wireless communication system 300.

FIG. 5 shows a system simulation diagram for verifying the effectiveness of an embodiment of the present disclosure. In this simulation, considering the complexity of deploying an antenna at an unmanned aerial vehicle, it is assumed that there are four uniformly distributed dual-polarized linear transmit antennas at the unmanned aerial vehicle and two dual-polarized at the network equipment side. Receive antenna. In addition, consider the following two scenarios. The first scenario includes only terrestrial terminal devices (eg, an average of 15 terrestrial terminal devices per cell), referred to herein as a C1 configuration. The second scenario includes terrestrial terminal equipment (eg, an average of 10 terrestrial terminal devices per cell) and an unmanned aerial vehicle (eg, an average of 5 unmanned aerial vehicles per cell), referred to herein as a C5 configuration. Using the first scenario as the baseline scenario, the second scenario is used to estimate the effects of UAV uplink interference and interference mitigation.

Referring to FIG. 5, there is shown performance of an uplink power control method that utilizes transmit beamforming gain to compensate for reduced transmit power, in accordance with an embodiment of the present disclosure. Line 510 (ie, terrestrial terminal device C1 utilizing a conventional ULPC) is a UL SINR cumulative distribution function (CDF) distribution of a terrestrial terminal device based on a conventional ULPC in a C1 configuration. Line 550 (ie, land terminal device C5 using conventional ULPC) is based in the C5 configuration UL SINR CDF distribution for terrestrial terminal equipment of conventional ULPC. Line 530 (ie, Extreme Interference UAV C5 utilizing conventional ULPC) is the UL SINR CDF distribution of a conventional ULPC based unmanned aerial vehicle in a C5 configuration.

As can be seen from Figure 5, the performance of the terrestrial terminal device is rapidly reduced from line 510 to line 550 due to the intervention of the UAV (i.e., line 530). After employing embodiments of the present disclosure (i.e., the UAV employs an enhanced ULPC), the performance of the terrestrial terminal equipment improves from line 550 to line 520 due to extreme interference with unmanned aerial vehicle UL interference mitigation. Therefore, due to the extreme interference with UAV UL interference mitigation, the loss of both land terminal equipment performance and UAV performance becomes acceptable, ie the terrestrial terminal equipment changes from line 510 to line 520, unmanned aircraft from line 530 Change to line 540.

FIG. 6 shows a block diagram of an apparatus 600 suitable for implementing embodiments of the present disclosure. Apparatus 600 can be used, for example, to implement components in unmanned aerial vehicle 130 or unmanned aerial vehicle 130 itself.

As shown in FIG. 6, device 600 includes a controller 610. Controller 610 controls the operation and functionality of device 600. For example, in some embodiments, controller 610 can perform various operations with instructions 630 stored in memory 620 coupled thereto. Memory 620 can be of any suitable type suitable for use in a local technology environment and can be implemented using any suitable data storage technology, including but not limited to semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices, and systems. Although only one memory cell is shown in FIG. 6, there may be multiple physically distinct memory cells in device 600.

Controller 610 can be of any suitable type suitable for use in a local technology environment and can include, but is not limited to, general purpose computers, special purpose computers, microcontrollers, digital signal controllers (DSPs), and controller-based multi-core controller architectures. One or more multiple. Device 600 can also include a plurality of controllers 610. Controller 610 is coupled to transceiver 640, which can receive and transmit information by means of one or more antennas 650 and/or other components.

In some embodiments, when the device 600 acts as an unmanned aerial vehicle 130 or a component therein, the controller 610 and the transceiver 640 can operate in conjunction to implement the above with reference to FIG. The method 400 is described. All of the features described above with reference to Figures 1-4 are applicable to device 600 and will not be described again herein.

As used herein, the term "include" and its analogous terms are to be understood as an open-ended, ie, "including but not limited to". The term "based on" should be understood to mean "based at least in part." The term "one embodiment" or "an embodiment" should be taken to mean "at least one embodiment." As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" can include computing, computing, processing, deriving, investigating, looking up (eg, looking up in a table, database, or another data structure), ascertaining, and the like. Further, "determining" can include receiving (eg, receiving information), accessing (eg, accessing data in memory), and the like. Further, "determining" may include parsing, selecting, selecting, establishing, and the like.

It should be noted that embodiments of the present disclosure may be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art will appreciate that the apparatus and methods described above can be implemented using computer-executable instructions and/or embodied in processor control code, such as in a programmable memory or data carrier such as an optical or electronic signal carrier. Such code.

In addition, although the operations of the methods of the present disclosure are described in a particular order in the drawings, this is not a requirement or implied that the operations must be performed in the particular order, or all of the illustrated operations must be performed to achieve the desired results. Instead, the steps depicted in the flowcharts can change the order of execution. Additionally or alternatively, certain steps may be omitted, the multiple steps being combined into one step, and/or one step being broken into multiple steps. It should also be noted that features and functions of two or more devices in accordance with the present disclosure may be embodied in one device. Conversely, the features and functions of one of the devices described above can be further divided into multiple devices.

While the disclosure has been described with reference to a particular embodiment, it is understood that the disclosure is not limited to the specific embodiments disclosed. The present disclosure is intended to cover various modifications and equivalents

Claims

A method for power control of an unmanned aerial vehicle, comprising:

Determining a first transmit power of the UAV and a transmit beamforming gain of the UAV to a serving base station;

Reducing the first transmit power to obtain a second transmit power based on the transmit beamforming gain;

A signal associated with the transmit beamforming gain is used to transmit a signal to the serving base station at the second transmit power.
The method of claim 1 further comprising:

Receiving, from the serving base station, a message indicating a desired received power of the serving base station for the UAV;

The second transmit power is adjusted based on the expected received power.
The method of claim 1 wherein transmitting a signal to the serving base station at the second transmit power using a beam associated with the transmit beamforming gain comprises:

Determining that the UAV is an extreme interference unmanned aerial vehicle that will generate interference greater than a predetermined interference threshold in the uplink;

In response to determining that the UAV is an extreme interference unmanned aerial vehicle, a signal associated with the transmit beamforming gain is used to transmit a signal to the serving base station at the second transmit power.
The method of claim 3 wherein determining that the UAV is an extreme interference unmanned aerial vehicle comprises:

Determining that the UAV is in an excessive interference state of the downlink by detecting interference in the downlink of the serving base station and the UAV;

The UAV is determined to be an extreme interference unmanned aerial vehicle based on determining that the UAV is in an excessively disturbing state of the downlink.
The method of claim 1 wherein determining the first transmit power of the UAV comprises:

The first transmit power is determined based on a nominal transmit power of the UAV and a path loss of the UAV to the serving base station.
The method of claim 1 wherein determining a transmit beamforming gain of the UAV to the serving base station comprises:

The transmit beamforming gain is determined based on a receive beamforming gain for the serving base station.
The method of claim 6 further comprising:

Determining a first signal to interference and noise ratio received from the serving base station using receive beamforming for the serving base station;

Determining a second signal to interference and noise ratio that is received from the serving base station without using the receive beamforming; and

The receive beamforming gain is determined based on the first signal to interference and noise ratio and the second signal to interference and noise ratio.
The method of claim 1 wherein obtaining the second transmit power comprises:

Determining the second transmit power to:

At the serving base station, between the received power in the case where the UAV uses the second transmit power and the beam and the received power in the case where the UAV uses the first transmit power Change is below a predetermined threshold, and

At the non-serving base station, the interference power in the case where the unmanned aerial vehicle uses the second transmission power and the beam is less than the interference power in the case where the unmanned aerial vehicle uses the first transmission power.
The method of claim 1 wherein obtaining the second transmit power comprises:

Receiving a scaling factor from the serving base station;

Using the scaling factor to scale the transmit beamforming gain;

The second transmit power is derived using the first transmit power minus the scaled transmit beamforming gain.
The method of claim 9 wherein said scaling factor is by a higher layer The determination is based on the adjustment of the beamforming gain and the difference between the uplink transmit beam and the downlink receive beam.
An unmanned aerial vehicle comprising:

At least one processor;

At least one memory including computer program instructions, the at least one memory and the computer program instructions being configured, with the at least one processor, to cause the unmanned aerial vehicle to:

Determining a first transmit power of the UAV and a transmit beamforming gain of the UAV to a serving base station;

Decreasing the first transmit power to obtain a second transmit power based on the beamforming gain;

A signal associated with the transmit beamforming gain is used to transmit a signal to the serving base station at the second transmit power.
The UAV of claim 11 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

Receiving, from the serving base station, a message indicating a desired received power of the serving base station for the UAV;

The second transmit power is adjusted based on the expected received power.
The UAV of claim 11 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

Determining that the UAV is an extreme interference unmanned aerial vehicle that will generate interference greater than a predetermined interference threshold in the uplink;

In response to determining that the UAV is an extreme interference unmanned aerial vehicle, a signal associated with the transmit beamforming gain is used to transmit a signal to the serving base station at the second transmit power.
The UAV of claim 13 wherein said at least one memory and said computer program instructions are further configured to interact with said at least one Together, the unmanned aerial vehicle is made:

Determining that the UAV is in an excessive interference state of the downlink by detecting interference in the downlink of the serving base station and the UAV;

The UAV is determined to be an extreme interference unmanned aerial vehicle based on determining that the UAV is in an excessively disturbing state of the downlink.
The UAV of claim 11 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

The first transmit power is determined based on a nominal transmit power of the UAV and a path loss of the UAV to the serving base station.
The UAV of claim 11 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

The transmit beamforming gain is determined based on a receive beamforming gain for the serving base station.
The UAV of claim 16 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

Determining a first signal to interference and noise ratio received from the serving base station using receive beamforming for the serving base station;

Determining a second signal to interference and noise ratio that is received from the serving base station without using the receive beamforming; and

The receive beamforming gain is determined based on the first signal to interference and noise ratio and the second signal to interference and noise ratio.
The UAV of claim 11 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

Determining the second transmit power to:

At the serving base station, using the second launch at the UAV The change between the power and the received power in the case of the beam and the received power in the case where the UAV uses the first transmit power is below a predetermined threshold, and

At the non-serving base station, the interference power in the case where the unmanned aerial vehicle uses the second transmission power and the beam is less than the interference power in the case where the unmanned aerial vehicle uses the first transmission power.
The UAV of claim 11 wherein said at least one memory and said computer program instructions are further configured to, with said at least one processor, cause said UAV to:

Receiving a scaling factor from the serving base station;

Using the scaling factor to scale the transmit beamforming gain;

The second transmit power is derived using the first transmit power minus the scaled transmit beamforming gain.
The UAV according to claim 19, wherein said scaling factor is determined by a higher layer based on an adjustment of said transmit beamforming gain and a difference between an uplink transmit beam and a downlink receive beam.
A computer program product tangibly stored on a non-transitory computer readable medium and comprising machine executable instructions that, when executed, cause the machine to perform according to claim 1 The method of any of the methods of any of 10.