WO2017096544A1 - 一种基于步长阈值机制的最佳中继位置搜寻方法及系统 - Google Patents

一种基于步长阈值机制的最佳中继位置搜寻方法及系统 Download PDF

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WO2017096544A1
WO2017096544A1 PCT/CN2015/096741 CN2015096741W WO2017096544A1 WO 2017096544 A1 WO2017096544 A1 WO 2017096544A1 CN 2015096741 W CN2015096741 W CN 2015096741W WO 2017096544 A1 WO2017096544 A1 WO 2017096544A1
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relay
communication performance
received signal
optimal
mobile relay
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French (fr)
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谢宁
陈敬坤
王晖
林晓辉
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Shenzhen University
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Shenzhen University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
    • H04W40/22—Communication route or path selection, e.g. power-based or shortest path routing using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Definitions

  • the invention belongs to the technical field of wireless communications, and in particular relates to an optimal relay location searching method and system based on a step threshold mechanism.
  • the communication relay is used to forward information sent between different nodes, which expands the communication range and improves the performance of the communication system.
  • Terrestrial radio communications are easily obstructed and shielded by obstacles, and aircraft, satellites, and unmanned aerial vehicles (UAVs) can act as communication relays because airborne relays can effectively interact with each other in rugged mountains or urban areas. The two sides of the communication establish a connection.
  • UAVs unmanned aerial vehicles
  • the existing algorithms for mobile relay location search mainly include: as shown in FIG. 1a, the location information of the source end (S) and the destination end (D) is measured based on the GPS, and the mobile relay uses the information to search for the best medium. Following position; Pertremum Seeking Control (ESC) algorithm; as shown in Figure 1b, based on airborne multi-antenna algorithm.
  • ESC Pertremum Seeking Control
  • the existing mobile relay location search algorithm can make the mobile relay find the best relay location, but the applicable scope of these algorithms also has certain deficiencies and defects, which are mainly reflected in: (1) source end (S) and The destination (D) requires GPS to measure its position and inform the mobile relay of the location information, that is, in such a relay communication system, the source (S), the destination (D), and the mobile All three need to rely on GPS, and rely on GPS to be vulnerable to attack, may also suffer from GPS spoofing or interference and cause relay communication failure. More importantly, in many special cases, the communication parties have no GPS function or the GPS device is damaged. Damage to GPS equipment caused by natural disasters. (2) Estimating the signal arrival angle (DOA) using the airborne multi-antenna to search for the best relay position, which is prone to estimation errors. Poor, and increase the complexity and algorithm complexity of the UAV communication device.
  • DOA signal arrival angle
  • the technical problem to be solved by the present invention is to provide an optimal relay location searching method and system based on a step threshold mechanism, which aims to solve the problem that the existing mobile relay relies on GPS in the process of searching for the relay location, and the use of the airborne antenna is easy. The problem that caused the estimation error.
  • the present invention is implemented in this way, an optimal relay location searching method based on a step threshold mechanism, and the steps include:
  • Step A A single mobile relay receives a test signal sent from the source end and amplifies it at any position in a fixed height plane of the test site, and then forwards the amplified test signal to the destination end;
  • Step B The destination end calculates communication performance according to the received signal, and generates single-bit information feedback to the mobile relay according to the comparison result of the calculated communication performance and the saved known best received signal communication performance; the single bit The information includes information on whether the performance is improved, and the known best received signal communication performance is the best communication performance that has been tested;
  • Step C The mobile relay calculates the next time position according to the fed single bit information and moves to the next time position, and repeats steps A-C until the optimal relay position is found.
  • step A the mobile relay starts the test at any position in the fixed height plane of the test site, and the initial position is the initialization position, and the initialization position is recorded as the known optimal position and exists in its own memory. Then, the test signal sent from the source is received and amplified, and the amplified test signal is forwarded to the destination.
  • step B the destination end calculates communication performance according to the received signal, and then compares the communication performance with the communication performance of the known best received signal stored in its own memory, and updates the known stored in the memory according to the comparison result.
  • the communication performance of the received signal is optimally received, and single bit information is generated and fed back to the mobile relay.
  • step C specifically includes:
  • Step C1 the mobile relay calculates the next moment position according to the single-bit information fed back and moves to The next time position, then return to step A to continue the first stage position search until the first stage optimal relay position is determined and then the first stage position search is ended;
  • Step C2 after the first stage location search ends, the mobile relay starts the second stage location search starting from the first phase optimal relay location, until determining the second phase optimal relay location, the second The optimal relay position for the phase is the final global optimal relay position in the fixed height plane.
  • step C1 specifically includes:
  • Step C11 the mobile relay records its known optimal position, and sets a first disturbance step, the known optimal position is represented by R 1 (n), and n represents an nth time slot;
  • Step C12 the mobile relay calculates the next time position according to the first disturbance step and moves to the next time position, returns to step A, receives the test signal transmitted from the source end, and amplifies and forwards to the destination end;
  • Step C13 the destination end calculates the communication performance of the new received signal, and compares the calculated communication performance with the stored communication performance of the known best received signal, if the new communication performance is better than the communication of the known best received signal.
  • Performance the communication performance of the new received signal is saved as the communication performance of the known best received signal, and then the destination end feeds back single-bit information to the mobile relay; if the new communication performance is better than the known best reception If the communication performance of the signal is poor, the communication performance of the saved known best received signal is unchanged, and then the destination end feeds back single-bit information to the mobile relay;
  • Step C14 The mobile relay determines the single bit information.
  • Step C15 when it is determined that the performance of the received signal is improved, the continuous negative feedback counter is cleared, the saved known optimal relay position is updated, and it is determined whether the first stage position search is ended;
  • Step C16 when it is determined that the performance of the received signal is not improved, the mobile relay returns to the position of the previous time slot, and the continuous negative feedback counter is incremented by 1, and the first disturbance step is modified to be the inverse of the first disturbance step of the previous time slot. And determining whether the continuous negative feedback counter reaches a preset continuous negative feedback threshold; the continuous negative feedback threshold is set to 2;
  • Step C17 if it is determined that the continuous negative feedback counter in step C16 reaches the preset continuous negative feedback threshold, the continuous negative feedback counter is cleared and the first disturbance step is decreased, and then it is determined whether the first stage position search is ended;
  • Step C18 if the first disturbance step is less than or equal to the preset first disturbance step threshold, ending the first-stage position search, and using the saved known optimal relay position as the first-stage optimal relay position;
  • step C2 specifically includes:
  • Step C21 The mobile relay sets a second interference step according to the first stage optimal relay position as a starting point
  • Step C22 the mobile relay calculates the next time position according to the second disturbance step and moves to the next time position, continues to receive the test signal transmitted from the source end, and amplifies and forwards to the destination end;
  • Step C23 the destination end calculates the communication performance of the new received signal, and compares the calculated communication performance with the saved communication performance of the known best received signal, if the new communication performance is better than the communication of the known best received signal.
  • Performance the communication performance of the new received signal is saved as the communication performance of the known best received signal, and then the destination end feeds back single-bit information to the mobile relay; if the new communication performance is better than the known best reception If the communication performance of the signal is poor, the communication performance of the saved known best received signal is unchanged, and then the destination end feeds back single-bit information to the mobile relay;
  • Step C24 the mobile relay determines the single bit information.
  • Step C25 When it is determined that the performance of the received signal is improved, the continuous negative feedback counter is cleared, the saved known optimal relay position is updated, and it is determined whether the second stage position search is ended.
  • Step C26 when it is determined that the performance of the received signal is not improved, the mobile relay returns to the position of the previous time slot, and the continuous negative feedback counter is incremented by 1, and the second disturbance step is modified to be the opposite of the second disturbance step of the previous time slot. And determining whether the continuous negative feedback counter reaches a preset continuous negative feedback threshold;
  • the continuous negative feedback threshold is set to 2;
  • Step C27 if it is determined that the continuous negative feedback counter in step C26 reaches the preset continuous negative feedback threshold, the continuous negative feedback counter is cleared and the second disturbance step is decreased, and then it is determined whether to end the second stage position search;
  • Step C28 if the second disturbance step is less than or equal to the preset second disturbance step threshold, the second stage position search is ended, and the saved known optimal relay position is used as the optimal relay position of the second stage.
  • the optimal relay position of the second stage is the final global optimal relay position in the fixed height plane;
  • the present invention also provides an optimal relay location searching system based on a step threshold mechanism, including a source end, a single mobile relay, and a destination end;
  • the source end is configured to send a test signal to the mobile relay
  • the mobile relay is configured to receive a test signal sent from the source end and perform amplification at any position of the test site, and then forward the amplified test signal to the destination end;
  • the destination end is configured to calculate communication performance according to the received signal, and generate single-bit information feedback to the mobile relay according to the comparison result of the calculated communication performance and the saved known best received signal communication performance;
  • the single bit information includes information on whether the performance is improved, the known best received signal communication performance is the best communication performance tested; the mobile relay calculates the next time position based on the feedback single bit information and moves to the next At a momentary position, the test signal transmitted from the source is continuously amplified and forwarded to the destination until the optimal relay position is found.
  • the mobile relay starts the test at any position in the fixed height plane of the test site, the initial position is the initialization position, the initialization position is recorded as the known optimal position and exists in its own memory, and then received from The test signal sent by the source is amplified and the amplified test signal is forwarded to the destination.
  • the destination end calculates communication performance according to the received signal, and then compares the communication performance with the communication performance of the known best received signal stored in its own memory, and updates according to the comparison result.
  • the communication performance of the known best received signal stored in the memory is generated and single bit information is generated and fed back to the mobile relay.
  • search system is specifically used to:
  • the mobile relay performs calculation according to the single-bit information of the feedback, moves to the next relay position according to the calculation result, and then performs the first-stage location search until determining the optimal relay position in the first phase and then ending the first phase.
  • the mobile relay starts the second phase location search starting from the first phase optimal relay location, until the second phase optimal relay location is determined, the second phase The optimal relay position is the final global optimal relay position in the fixed height plane.
  • the present invention has the beneficial effects that the present invention does not need to know the location information of the source end and the destination end, that is, the source end and the destination end do not need to have the GPS function, and only rely on the positioning function of the mobile relay itself to be global. Finding the best relay location in the range, compared with the source, destination and mobile relay of the existing algorithm, the GPS function is required, the limitation is reduced, and the applicable scenario is expanded.
  • FIG. 2 is a flowchart of an optimal relay location searching method based on a step threshold mechanism according to an embodiment of the present invention.
  • FIG. 3 is a schematic structural diagram of an optimal relay location searching system based on a step threshold mechanism for using a drone as a mobile relay according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of an end-to-end signal to noise ratio corresponding to a relay position according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of a time slot and a signal to noise ratio of a search process using a drone as an optimal location for a mobile relay according to an embodiment of the present invention.
  • the shortcomings and defects of the optimal relay location search algorithm for existing mobile relays are: (1) The source (S) and destination (D) need to use their own GPS function to measure their location information and send the information. For mobile relay, relying on GPS function is vulnerable to attack and interference, resulting in location search failure; (2) For communication devices without GPS function or GPS damage, some existing algorithms are unusable; (3) more onboard Antennas increase the complexity of mobile relays compared to single antennas, and inevitably have angle estimation errors, which also increases the complexity of the algorithm. The new algorithm does not need to know the location information of the source (S) and the destination (D), that is, the source (S) and the destination (D) do not need GPS function, and only rely on the positioning function of the mobile relay itself can be global.
  • the UAV relay technology uses the adaptive variable step size algorithm to control the UAV to automatically search for the optimal relay position, which can effectively improve the performance of the communication system.
  • the present invention provides an optimal relay location searching method based on a step threshold mechanism as shown in FIG. 2, and the steps include:
  • a single mobile relay receives a test signal sent from the source and amplifies it at any position in a fixed height plane of the test site, and then forwards the amplified test signal to the destination.
  • the mobile relay starts the test at any position in the fixed height plane of the test site, and the start position is the initialization position, the initialization position is recorded as the known optimal position and exists in its own memory, and then The test signal sent from the source is received and amplified, and the amplified test signal is forwarded to the destination.
  • the destination end calculates communication performance according to the received signal, and generates single-bit information feedback to the mobile relay according to the comparison result of the calculated communication performance and the saved known best received signal communication performance; the single-bit information Including information on whether the performance is improved, the known best received signal communication performance is the best communication performance that has been tested.
  • the destination calculates communication based on the received signal. And then comparing the communication performance with the communication performance of the known best received signal stored in its own memory, updating the communication performance of the known best received signal stored in the memory according to the comparison result, and generating single bit information feedback to The mobile relay.
  • the mobile relay calculates a next time position according to the fed single bit information and moves to the next time position, and repeats steps S1-S3 until an optimal relay position is found.
  • step S3 specifically includes:
  • the mobile relay calculates a next time position according to the single bit information of the feedback and moves to the next time position, and then returns to step S1 to continue the first stage position search until the first stage optimal relay position is determined. Then ending the first stage location search;
  • the mobile relay starts the second phase location search starting from the first phase optimal relay location, until the second phase optimal relay location is determined, and the second phase The optimal relay position is the final global optimal relay position in the fixed height plane.
  • step S31 specifically includes:
  • the mobile relay records its known optimal position, and sets a first disturbance step, the known optimal position is represented by R 1 (n), and n represents an nth time slot;
  • the mobile relay calculates the next time position according to the first disturbance step and moves to the next time position, returns to step S1, receives the test signal transmitted from the source end, and amplifies and forwards to the destination end;
  • the mobile relay calculates the next time position according to the first disturbance step, and sets the first disturbance step threshold.
  • the destination end calculates the communication performance of the new received signal, and compares the calculated communication performance with the saved communication performance of the known best received signal, if the new communication performance is better than the communication performance of the known best received signal. And storing the communication performance of the new received signal as the communication performance of the known best received signal, and then the destination end feeds back the single bit information to the mobile relay; if the new communication performance is better than the known best received signal Poor communication performance, the communication performance of the known best received signal is not saved Changing, then the destination end feeds back single-bit information to the mobile relay;
  • the mobile relay determines the single bit information.
  • the mobile relay when it is determined that the performance of the received signal is not improved, the mobile relay returns to the position of the previous time slot, and the continuous negative feedback counter is incremented by 1, and the first disturbance step is modified to be the inverse of the first disturbance step of the previous time slot. And determining whether the continuous negative feedback counter reaches a preset continuous negative feedback threshold; the continuous negative feedback threshold is set to 2;
  • step S316 If it is determined that the continuous negative feedback counter in step S316 reaches a preset continuous negative feedback threshold, the continuous negative feedback counter is cleared and the first disturbance step is decreased, and then it is determined whether the first stage position search is ended.
  • step S32 specifically includes:
  • the mobile relay calculates a next time position according to the second disturbance step and moves to the next time position, continues to receive the test signal transmitted from the source end, and amplifies and forwards to the destination end;
  • R 2 (n) represents the known best relay position
  • ⁇ y represents the second disturbance step
  • the known optimal position is continuously updated with the first stage optimal relay position as the starting point, that is, the first known best position for positional movement, and then the subsequent positional movement.
  • the destination calculates the communication performance of the new received signal, and compares the calculated communication performance with the saved communication performance of the known best received signal, if the new communication performance is better than the communication performance of the known best received signal And storing the communication performance of the new received signal as the communication performance of the known best received signal, and then the destination end feeds back the single bit information to the mobile relay; if the new communication performance is better than the known best received signal Poor communication performance, the communication performance of the saved known best received signal is unchanged, and then the destination end feeds back single-bit information to the mobile relay;
  • the mobile relay determines the single bit information.
  • the mobile relay when it is determined that the performance of the received signal is not improved, the mobile relay returns to the position of the previous time slot, and the continuous negative feedback counter is incremented by 1, and the second disturbance step is modified to be the opposite of the second disturbance step of the previous time slot. And determining whether the continuous negative feedback counter reaches a preset continuous negative feedback threshold; the continuous negative feedback threshold is set to 2;
  • step S327 if it is determined that the continuous negative feedback counter in step S326 reaches a preset continuous negative feedback threshold, the continuous negative feedback counter is cleared and the second disturbance step is decreased, and then it is determined whether to end the second stage position search;
  • the second stage position search is ended, and the saved known optimal relay position is used as the optimal relay position of the second stage.
  • the optimal relay position of the second stage is the final global optimal relay position in the fixed height plane;
  • the mobile relay may be a drone, a satellite, a hot air balloon, etc.
  • a drone is used as a mobile relay.
  • the present invention will be further described in conjunction with FIGS. 3 to 5:
  • an optimal relay location searching system based on a step threshold mechanism based on a step threshold mechanism for mobile relay including a source end, a single mobile relay, and a destination end. ;
  • the source end is configured to send a test signal to the mobile relay
  • the mobile relay is configured to receive a test signal sent from the source end and perform amplification at any position of the test site, and then forward the amplified test signal to the destination end;
  • the destination end is configured to calculate communication performance according to the received signal, and generate single-bit information feedback to the mobile relay according to the comparison result of the calculated communication performance and the saved known best received signal communication performance;
  • the single bit information includes information on whether the performance is improved, the known best received signal communication performance is the best communication performance tested; the mobile relay calculates the next time position based on the feedback single bit information and moves to the next At a momentary position, the test signal transmitted from the source is continuously amplified and forwarded to the destination until the optimal relay position is found.
  • the source end and the destination end can perform functional switching, that is, in the implementation process, the source end and the destination end simultaneously have the functions of sending training timing and performing signal processing.
  • S(x s , y s , z s ) represents the position coordinates of the source end
  • R(x, y, z) represents the position coordinates of the drone
  • D(x d , y d , z d ) represents the position coordinates of the destination.
  • the communication distances of the drone R(x, y, z) from the source end S(x s , y s , z s ) and the destination end R (x, y, z) are:
  • First hop communication the source (S) transmits a signal to the drone (R),
  • y R represents the signal received by the drone
  • x represents the signal transmitted by S
  • P S represents the transmission power of S
  • n 1 is additive white Gaussian noise satisfying E[
  • 2 ] N 01 . Is the free space path loss of the first hop channel.
  • Second hop communication The drone (R) amplifies the received signal to the destination (D)
  • y D represents the signal received by the destination
  • G represents the relay gain
  • n 2 is additive white Gaussian noise satisfying E[
  • 2 ] N 02 . Is the free space path loss of the second hop channel.
  • the gain G is as follows:
  • ⁇ 1 and ⁇ 2 are as follows:
  • the optimal relay location search method based on the step threshold mechanism is specifically searched in two stages:
  • the drone records its best known position R 1 (n) in memory, expressed as coordinates
  • ⁇ x is the initial disturbance step size of the first stage of the algorithm, and n represents the time slot;
  • the destination end records the communication performance (signal-to-noise ratio, bit error rate, data rate, etc.) corresponding to the best known position in the memory;
  • D measures the communication performance Q(n) of the new received signal and updates the best received signal communication performance in its memory.
  • the destination then feeds back a single bit of information (assuming that the bit is error-free during transmission) to the drone to indicate whether the communication performance is improved.
  • R 1 (n+1) R 1 (n)+ ⁇ x ;
  • R 1 (n+1) R 1 (n);
  • ⁇ x - ⁇ x ;
  • ⁇ x ⁇ x ⁇ R D ;
  • the drone determines whether to stop the first stage search and initiate the second stage search. If the first disturbance disturbance step size ⁇ x is less than or equal to the predetermined first disturbance step threshold ⁇ thx , the first stage position search is stopped. And recording the best known position of the first stage position search, the position is the first relay position, and then starting the second stage search; if the first disturbance step size ⁇ x is greater than the predetermined threshold ⁇ thx , returning to step 1) , continue the first stage of the search.
  • ⁇ y is the initial perturbation step size of the second stage of the algorithm.
  • the drone calculates its next position And move to that location.
  • the destination measures the communication performance Q(n) of the new received signal and updates the best received signal communication performance in its memory.
  • R 2 (n+1) R 2 (n)+ ⁇ y
  • R 2 (n+1) R 2 (n)
  • ⁇ y ⁇ y ⁇ R D ;
  • the drone determines whether to stop the second-stage search. If the second disturbance step ⁇ y is less than or equal to the predetermined threshold ⁇ thy , the second-stage search is stopped, and the entire search process ends, and the last position of the drone is The optimal relay position found; if the disturbance step size ⁇ y is greater than the predetermined threshold ⁇ thy , then return to step 6) to continue the second stage of searching.
  • the height of the drone is fixed: 30m;
  • the X axis represents the abscissa
  • the Y axis represents the ordinate
  • the Z axis represents the signal to noise ratio ⁇ end corresponding to the coordinate point.
  • the horizontal axis represents the number of time slots spent by the drone in searching for the best position
  • the vertical axis represents the end-to-end signal-to-noise ratio ⁇ end
  • the letter of the drone at the starting position R(1) can be seen.
  • the noise ratio is -0.7352dB
  • the signal-to-noise ratio of the 12th time slot ie, R(12) position
  • the first stage of the search is stopped and the second stage search is started in the 20th time slot.
  • the signal-to-noise ratio at the 37th time slot (ie, R(37) position) is 2.187dB, and the maximum point in Figure 4 is found, that is, the optimal relay position is found, in the 40th time slot. End the second stage of the search.
  • the invention belongs to the field of wireless communication technologies and can be applied to search for a global optimal relay position in a three-dimensional space and improve the performance of relay communication.
  • Potential application scenarios include the construction of temporary communication systems and communication connections at disaster sites.

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Abstract

本发明适用于无线通信技术领域，提供了基于步长阈值机制的最佳中继位置搜寻方法，步骤包括：A，移动中继在测试场所的固定高度平面内的任意位置，接收来自源端的测试信号并放大转发至目的端；B，目的端根据接收到的信号计算通信性能，根据与已知最佳接收信号通信性能的比较结果生成单比特信息反馈至移动中继；C，移动中继根据单比特信息计算下一时刻位置并移动，重复A-C，直至找到最佳中继位置。本发明无需知道源端和目的端的位置信息，仅仅依靠移动中继自身的定位功能和目的端反馈单比特信息就能够在全局范围内找到最佳的中继位置，相比于现有算法的源端、目的端和移动中继都需要具备GPS功能来说，所受到的限制减少了，适用场景扩大。

Description

一种基于步长阈值机制的最佳中继位置搜寻方法及系统 技术领域
本发明属于无线通信技术领域，尤其涉及一种基于步长阈值机制的最佳中继位置搜寻方法及系统。
背景技术
通信中继用来转发不同的节点之间发出的信息，扩大了通信范围，提高了通信系统的性能。陆地无线电通信很容易被障碍物遮挡和屏蔽，飞机、卫星及无人机(Unmanned Aerial Vehicles，UAVs)可以充当通信中继，因为机载中继可以在崎岖的山区或市区有效地为需要相互通信的双方建立起连接。近年来，使用无人机作为通信中继的问题已吸引不少学者的关注和研究，同时其应用也十分广泛。
现有的应用于移动中继位置搜寻的算法主要有：如图1a，基于GPS去测量源端(S)和目的端(D)的位置信息，移动中继再利用该信息去搜寻最佳中继位置；基于扰动的极值搜索控制(Extremum Seeking Control，ESC)算法；如图1b，基于机载多天线的算法。现有的移动中继位置搜寻算法都可以使移动中继找到最佳的中继位置，但是这些算法的适用范围也存在一定的不足和缺陷，主要体现在：(1)源端(S)和目的端(D)都需要GPS来测量自身的位置并将该位置信息告知移动中继，也就是说，在这样的中继通信系统中，源端(S)、目的端(D)和移动中继三者都需要依赖GPS，而依赖于GPS容易受到攻击，也可能遭受GPS欺骗或干扰而导致中继通信失败，更重要的是，在很多特殊情况下通信双方没有GPS功能或者GPS设备已损坏，如自然灾害导致GPS设备损坏。(2)使用机载多天线对信号到达角(DOA)进行估计来搜寻最佳中继位置，容易出现估计误 差，且增加了无人机通信设备的复杂度和算法复杂度。
发明内容
本发明所要解决的技术问题在于提供一种基于步长阈值机制的最佳中继位置搜寻方法及系统，旨在解决现有移动中继在中继位置寻找过程中依赖GPS，使用机载天线容易导致估计误差的问题。
本发明是这样实现的，一种基于步长阈值机制的最佳中继位置搜寻方法，步骤包括：
步骤A，单个移动中继在测试场所的固定高度平面内的任意位置，接收来自源端发送的测试信号并进行放大，然后将放大的测试信号转发至目的端；
步骤B，目的端根据接收到的信号计算通信性能，并根据计算的通信性能与保存的已知最佳接收信号通信性能的比较结果生成单比特信息反馈至所述移动中继；所述单比特信息包括性能是否提高的信息，所述已知最佳接收信号通信性能为已测试的最好通信性能；
步骤C，所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，重复步骤A-C，直至找到最佳中继位置。
进一步地，步骤A中，移动中继位于测试场所的固定高度平面内的任意位置开始测试，以起始位置为初始化位置，将所述初始化位置记录为已知最佳位置并存在自身的内存中，然后接收来自源端发送的测试信号并进行放大，将放大的测试信号转发至目的端。
进一步地，步骤B中，目的端根据接收的信号计算通信性能，然后将所述通信性能与自身内存保存的已知最佳接收信号的通信性能进行比较，根据比较结果更新内存中保存的已知最佳接收信号的通信性能，并生成单比特信息反馈至所述移动中继。
进一步地，步骤C具体包括：
步骤C1，所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至 该下一时刻位置，然后返回步骤A，继续进行第一阶段位置搜寻，直至确定第一阶段最佳中继位置然后结束第一阶段位置搜寻；
步骤C2，第一阶段位置搜寻结束之后，移动中继以所述第一阶段最佳中继位置为起点开始进行第二阶段位置搜寻，直至确定第二阶段最佳中继位置，所述第二阶段最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置。
进一步地，步骤C1具体包括：
步骤C11，所述移动中继记录其已知最佳位置，并设置第一扰动步长，所述已知最佳位置用R1(n)表示，n表示第n个时隙；
步骤C12，所述移动中继根据第一扰动步长计算下一时刻位置并移动到该下一时刻位置，返回步骤A，接收来自源端发射的测试信号并放大转发至目的端；
以
Figure PCTCN2015096741-appb-000001
表示所述下一时刻位置，以Δx表示所述第一扰动步长，则：
Figure PCTCN2015096741-appb-000002
所述第一扰动步长的初始值预设为Δx＝(x0，0，0)；
步骤C13，目的端计算新的接收信号的通信性能，根据计算出的通信性能与保存的已知最佳接收信号的通信性能进行比较，若新的通信性能优于已知最佳接收信号的通信性能，则将所述新的接收信号的通信性能保存为已知最佳接收信号的通信性能，然后目的端反馈单比特信息给所述移动中继；若新的通信性能比已知最佳接收信号的通信性能差，则保存的已知最佳接收信号的通信性能不变，然后目的端反馈单比特信息给所述移动中继；
步骤C14，所述移动中继对所述单比特信息进行判断；
步骤C15，在判断为接收信号性能提升时，将连续负反馈计数器清零，更新保存的已知最佳中继位置，并判断是否结束第一阶段位置搜寻；
步骤C16，在判断为接收信号性能未提升时，移动中继返回上一时隙的位置，同时连续负反馈计数器加1，第一扰动步长修改为上一时隙的第一扰动步长的相反数，并判断连续负反馈计数器是否达到预设的连续负反馈阈值；所述连续负反馈阈值设定为2；
步骤C17，若判断步骤C16中的连续负反馈计数器达到预设的连续负反馈阈值，则连续负反馈计数器清零并减小第一扰动步长，然后判断是否结束第一阶段位置搜寻；
步骤C18，若第一扰动步长小于等于预设的第一扰动步长阈值，则结束第一阶段位置搜寻，并将保存的已知最佳中继位置作为第一阶段最佳中继位置；
若扰动步长大于预设的第一扰动步长阈值，则返回步骤C12。
进一步地，步骤C2具体包括：
步骤C21，移动中继根据所述第一阶段最佳中继位置为起点，设置第二扰动步长；
步骤C22，所述移动中继根据第二扰动步长计算下一时刻位置并移动到该下一时刻位置，继续接收来自源端发射的测试信号并放大转发至目的端；
以
Figure PCTCN2015096741-appb-000003
表示下一时刻位置，以R2(n)表示已知最佳中继位置，以Δy表示所述第二扰动步长，则：
Figure PCTCN2015096741-appb-000004
所述第二扰动步长的初始值预设为则Δy＝(0，y0，0)；
步骤C23，目的端计算新的接收信号的通信性能，根据计算出的通信性能与保存的已知最佳接收信号的通信性能进行比较，若新的通信性能优于已知最佳接收信号的通信性能，则将所述新的接收信号的通信性能保存为已知最佳接收信号的通信性能，然后目的端反馈单比特信息给所述移动中继；若新的通信性能比已知最佳接收信号的通信性能差，则保存的已知最佳接收信号的通信性能不变，然后目的端反馈单比特信息给所述移动中继；
步骤C24，所述移动中继对所述单比特信息进行判断；
步骤C25，在判断为接收信号性能提升时，将连续负反馈计数器清零，更新保存的已知最佳中继位置，并判断是否结束第二阶段位置搜寻；
步骤C26，在判断为接收信号性能未提升时，移动中继返回上一时隙的位置，同时连续负反馈计数器加1，第二扰动步长修改为上一时隙的第二扰动步长的相反数，并判断连续负反馈计数器是否达到预设的连续负反馈阈值；所述 连续负反馈阈值设定为2；
步骤C27，若判断步骤C26中的连续负反馈计数器达到预设的连续负反馈阈值，则连续负反馈计数器清零并减小第二扰动步长，然后判断是否结束第二阶段位置搜寻；
步骤C28，若第二扰动步长小于等于预设的第二扰动步长阈值，则结束第二阶段位置搜寻，并将保存的已知最佳中继位置作为第二阶段的最佳中继位置，所述第二阶段的最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置；
若扰动步长大于预设的第二扰动步长阈值，则返回步骤C22。
本发明还提供了一种基于步长阈值机制的最佳中继位置搜寻系统，包括源端、单个移动中继和目的端；
所述源端，用于发送测试信号至所述移动中继；
所述移动中继，用于在测试场所的任意位置，接收来自源端发送的测试信号并进行放大，然后将放大测试信号转发至所述目的端；
所述目的端，用于根据接收到的信号计算通信性能，并根据计算的通信性能与保存的已知最佳接收信号通信性能的比较结果生成单比特信息反馈至所述移动中继；所述单比特信息包括性能是否提高的信息，所述已知最佳接收信号通信性能为已测试的最好通信性能；所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，继续将源端传输的测试信号进行放大后转发至所述目的端，直至找到最佳中继位置。
进一步地，移动中继位于测试场所的固定高度平面内的任意位置开始测试，以起始位置为初始化位置，将所述初始化位置记录为已知最佳位置并存在自身的内存中，然后接收来自源端发送的测试信号并进行放大，将放大的测试信号转发至目的端。
进一步地，目的端根据接收到的信号计算通信性能，然后将所述通信性能与自身内存保存的已知最佳接收信号的通信性能进行比较，根据比较结果更新 内存中保存的已知最佳接收信号的通信性能，并生成单比特信息反馈至所述移动中继。
进一步地，所述搜寻系统具体还用于：
首先，所述移动中继根据反馈的单比特信息进行计算，根据计算结果移动至下一中继位置，然后进行第一阶段位置搜寻，直至确定第一阶段最佳中继位置然后结束第一阶段位置搜寻；
最后，第一阶段位置搜寻结束之后，移动中继以所述第一阶段最佳中继位置为起点开始进行第二阶段位置搜寻，直至确定第二阶段最佳中继位置，所述第二阶段最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置。
本发明与现有技术相比，有益效果在于：本发明无需知道源端和目的端的位置信息，即源端和目的端不需要具备GPS功能，仅仅依靠移动中继自身的定位功能就能够在全局范围内找到最佳的中继位置，相比于现有算法的源端、目的端和移动中继都需要具备GPS功能来说，所受到的限制减少了，适用场景扩大。
附图说明
图1是现有技术提供的最佳中继位置搜寻算法的流程图。
图2是本发明实施例提供的一种基于步长阈值机制的最佳中继位置搜寻方法的流程图。
图3是本发明实施例提供的一种基于步长阈值机制的以无人机为移动中继的最佳中继位置搜寻系统的结构示意图。
图4是本发明实施例提供的中继位置对应的端到端的信噪比示意图。
图5是本发明实施例提供的使用无人机作为移动中继最佳位置的搜寻过程所花时隙与达到信噪比的示意图。
具体实施方式
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
针对现有移动中继最佳中继位置搜寻算法的不足和缺陷，即：(1)源端(S)和目的端(D)需要利用自身的GPS功能测量自己的位置信息并把该信息发送给移动中继，依赖GPS功能容易受到攻击和干扰而导致位置搜寻失败；(2)对于没有GPS功能或者GPS已损坏的通信设备，现有的一些算法是无法使用的；(3)机载多天线相比于单天线增加了移动中继的复杂性，且不可避免的会有角度估计误差，同时也增加了算法的复杂性。新算法无需知道源端(S)和目的端(D)的位置信息，即源端(S)和目的端(D)不需要具备GPS功能，仅仅依靠移动中继自身的定位功能就能够在全局范围内找到最佳的中继位置，相比于现有算法的源端(S)、目的端(D)和移动中继都需要具备GPS功能来说，所受到的限制减少了，适用场景扩大。无人机中继技术，利用自适应变步长算法去控制无人机自动搜寻最佳中继位置，能有效地提升通信系统性能。
基于上述理论，本发明提供了如图2所示的一种基于步长阈值机制的最佳中继位置搜寻方法，步骤包括：
S1，单个移动中继在测试场所的固定高度平面内的任意位置，接收来自源端发送的测试信号并进行放大，然后将放大的测试信号转发至目的端。在本步骤中，移动中继位于测试场所的固定高度平面内的任意位置开始测试，以起始位置为初始化位置，将所述初始化位置记录为已知最佳位置并存在自身的内存中，然后接收来自源端发送的测试信号并进行放大，将放大的测试信号转发至目的端。
S2，目的端根据接收到的信号计算通信性能，并根据计算的通信性能与保存的已知最佳接收信号通信性能的比较结果生成单比特信息反馈至所述移动中继；所述单比特信息包括性能是否提高的信息，所述已知最佳接收信号通信性能为已测试的最好通信性能。在本步骤中，目的端根据接收的信号计算通信性 能，然后将所述通信性能与自身内存保存的已知最佳接收信号的通信性能进行比较，根据比较结果更新内存中保存的已知最佳接收信号的通信性能，并生成单比特信息反馈至所述移动中继。
S3，所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，重复步骤S1-S3，直至找到最佳中继位置。
进一步地，上述步骤S3具体包括：
S31，所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，然后返回步骤S1，继续进行第一阶段位置搜寻，直至确定第一阶段最佳中继位置然后结束第一阶段位置搜寻；
S32，第一阶段位置搜寻结束之后，移动中继以所述第一阶段最佳中继位置为起点开始进行第二阶段位置搜寻，直至确定第二阶段最佳中继位置，所述第二阶段最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置。
进一步地，步骤S31具体包括：
S311，所述移动中继记录其已知最佳位置，并设置第一扰动步长，所述已知最佳位置用R1(n)表示，n表示第n个时隙；
S312，所述移动中继根据第一扰动步长计算下一时刻位置并移动到该下一时刻位置，返回步骤S1，接收来自源端发射的测试信号并放大转发至目的端；
以
Figure PCTCN2015096741-appb-000005
表示所述下一时刻位置，以Δx表示所述第一扰动步长，则：
Figure PCTCN2015096741-appb-000006
所述第一扰动步长的初始值预设为Δx＝(x0，0，0)。在本步骤中，移动中继根据第一扰动步长计算下一时刻位置，同时设置第一扰动步长阈值。
S313，目的端计算新的接收信号的通信性能，根据计算出的通信性能与保存的已知最佳接收信号的通信性能进行比较，若新的通信性能优于已知最佳接收信号的通信性能，则将所述新的接收信号的通信性能保存为已知最佳接收信号的通信性能，然后目的端反馈单比特信息给所述移动中继；若新的通信性能比已知最佳接收信号的通信性能差，则保存的已知最佳接收信号的通信性能不 变，然后目的端反馈单比特信息给所述移动中继；
S314，所述移动中继对所述单比特信息进行判断；
S315，在判断为接收信号性能提升时，将连续负反馈计数器清零，更新保存的已知最佳中继位置，并判断是否结束第一阶段位置搜寻；
S316，在判断为接收信号性能未提升时，移动中继返回上一时隙的位置，同时连续负反馈计数器加1，第一扰动步长修改为上一时隙的第一扰动步长的相反数，并判断连续负反馈计数器是否达到预设的连续负反馈阈值；所述连续负反馈阈值设定为2；
S317，若判断步骤S316中的连续负反馈计数器达到预设的连续负反馈阈值，则连续负反馈计数器清零并减小第一扰动步长，然后判断是否结束第一阶段位置搜寻；
S318，若第一扰动步长小于等于预设的第一扰动步长阈值，则结束第一阶段位置搜寻，并将保存的已知最佳中继位置作为第一阶段最佳中继位置；
若扰动步长大于预设的第一扰动步长阈值，则返回步骤S312。
进一步地，步骤S32具体包括：
S321，移动中继根据所述第一阶段最佳中继位置为起点，设置第二扰动步长；以Δy表示所述第二扰动步长，所述第二扰动步长的初始值预设为则Δy＝(0，y0，0)。在本步骤中，在增加第二扰动步长的同时，设置第二扰动步长的阈值。
S322，所述移动中继根据第二扰动步长计算下一时刻位置并移动到该下一时刻位置，继续接收来自源端发射的测试信号并放大转发至目的端；
以
Figure PCTCN2015096741-appb-000007
表示下一时刻位置，以R2(n)表示已知最佳中继位置，以Δy表示所述第二扰动步长，则：
Figure PCTCN2015096741-appb-000008
所述第二扰动步长的初始值预设为则Δy＝(0，y0，0)。在本步骤中。以所述第一阶段最佳中继位置为起点，即最初的已知最佳位置进行位置移动，后再后续的位置移动中，不断更新已知最佳位置。
S323，目的端计算新的接收信号的通信性能，根据计算出的通信性能与保存的已知最佳接收信号的通信性能进行比较，若新的通信性能优于已知最佳接收信号的通信性能，则将所述新的接收信号的通信性能保存为已知最佳接收信号的通信性能，然后目的端反馈单比特信息给所述移动中继；若新的通信性能比已知最佳接收信号的通信性能差，则保存的已知最佳接收信号的通信性能不变，然后目的端反馈单比特信息给所述移动中继；
S324，所述移动中继对所述单比特信息进行判断；
S325，在判断为接收信号性能提升时，将连续负反馈计数器清零，更新保存的已知最佳中继位置，并判断是否结束第二阶段位置搜寻；
S326，在判断为接收信号性能未提升时，移动中继返回上一时隙的位置，同时连续负反馈计数器加1，第二扰动步长修改为上一时隙的第二扰动步长的相反数，并判断连续负反馈计数器是否达到预设的连续负反馈阈值；所述连续负反馈阈值设定为2；
S327，若判断步骤S326中的连续负反馈计数器达到预设的连续负反馈阈值，则连续负反馈计数器清零并减小第二扰动步长，然后判断是否结束第二阶段位置搜寻；
S328，若第二扰动步长小于等于预设的第二扰动步长阈值，则结束第二阶段位置搜寻，并将保存的已知最佳中继位置作为第二阶段的最佳中继位置，所述第二阶段的最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置；
若扰动步长大于预设的第二扰动步长阈值，则返回步骤S322。
在实际应用中，移动中继可以是无人机、卫星、热气球等，在本实施例中，使用无人机作为移动中继。下面，结合图3至图5对本发明进行进一步的阐述：
如图3所示，为本发明实施例提供了一种基于基于步长阈值机制的以无人机为移动中继的最佳中继位置搜寻系统，包括源端、单个移动中继和目的端；
所述源端，用于发送测试信号至所述移动中继；
所述移动中继，用于在测试场所的任意位置，接收来自源端发送的测试信号并进行放大，然后将放大测试信号转发至所述目的端；
所述目的端，用于根据接收到的信号计算通信性能，并根据计算的通信性能与保存的已知最佳接收信号通信性能的比较结果生成单比特信息反馈至所述移动中继；所述单比特信息包括性能是否提高的信息，所述已知最佳接收信号通信性能为已测试的最好通信性能；所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，继续将源端传输的测试信号进行放大后转发至所述目的端，直至找到最佳中继位置。
在实际应用过程中，源端和目的端可以进行功能上的相互切换，即：在实施过程中，源端和目的端同时具备发送训练时序和进行信号处理等功能。
具体的，在图3的空间直角坐标系所示，S(xs，ys，zs)表示源端的位置坐标，R(x，y，z)表示无人机的位置坐标，D(xd，yd，zd)表示目的端的位置坐标。则无人机R(x，y，z)离源端S(xs，ys，zs)与目的端R(x，y，z)的通信距离分别是：
Figure PCTCN2015096741-appb-000009
移动中继通信过程：
第一跳通信：源端(S)发射信号给无人机(R)，
Figure PCTCN2015096741-appb-000010
yR表示无人机接收到的信号，x表示S发射的信号，PS表示S的发射功率，n1是满足E[|n1|2]＝N01的加性高斯白噪声。
Figure PCTCN2015096741-appb-000011
是第一跳信道的自由空间路径损耗。
第二跳通信：无人机(R)将接受到的信号放大转发给目的端(D)
Figure PCTCN2015096741-appb-000012
yD表示目的端接收到的信号，G表示中继增益，n2是满足E[|n2|2]＝N02的加 性高斯白噪声。
Figure PCTCN2015096741-appb-000013
是第二跳信道的自由空间路径损耗。
其中增益G如下：
Figure PCTCN2015096741-appb-000014
由公式(2)得到端到端的信噪比为：
Figure PCTCN2015096741-appb-000015
其中γ1、γ2如下：
Figure PCTCN2015096741-appb-000016
基于步长阈值机制的最佳中继位置搜寻方法，步骤具体分两个阶段搜寻：
第一阶段搜寻：
1)无人机在内存中记录其最佳已知位置R1(n)，用坐标表示为
Figure PCTCN2015096741-appb-000017
在每个迭代时隙增加一个第一扰动步长Δx，并设置第一扰动步长阈值Δthx，用坐标表示为Δx＝(x0，0，0)。Δx为本算法第一阶段的初始扰动步长，n表示时隙；目的端在内存中记录与最佳已知位置相应的通信性能(信噪比、误码率、数据速率等)；无人机的起始位置作为初始化位置，并将该初始化位置R(1)记录为最佳已知位置，相应地，目的端将与该初始化位置对应的通信性能Q(1)记录为最佳已知位置的通信性能Qbest(1)＝Q(1)。
2)无人机计算它的下一个位置
Figure PCTCN2015096741-appb-000018
并移动到该位置。
3)D测量新的接收信号的通信性能Q(n)，并且更新其内存中的最佳接收信号通信性能，更新规则为Qbest(n+1)＝max(Qbest(n)，Q(n))。随后目的端反馈一单比 特信息(假设该比特在传输过程中无误码)给无人机，以表明此次通信性能是否提高。
4)无人机根据反馈回来的单比特信息，更新自己的最佳已知位置R1(n)，更新规则如下：(CN表示连续负反馈计数器，连续负反馈计数器阈值CT＝2；扰动步长下降因子RD，取经验值。)
if Q(n)＞Qbest(n)
R1(n+1)＝R1(n)+Δx；
CN＝0；
else
R1(n+1)＝R1(n)；
CN＝CN+1；
Δx＝-Δx；
if CN≥CT
Δx＝Δx·RD；
CN＝0；
end
end
5)无人机判断是否停止第一阶段的搜寻并启动第二阶段搜寻，若第一扰动扰动步长Δx小于等于预定的第一扰动步长阈值Δthx，则则停止第一阶段位置搜寻并记录第一阶段位置搜寻的最佳已知位置，以该位置为第一中继位置，然后启动第二阶段搜寻；若第一扰动步长Δx大于预定阈值Δthx，则返回步骤1)，继续第一阶段的搜寻。
第二阶段搜寻：
(第一阶段结束，表示找到了X轴上的最优位置，接下来将在该X轴最优位置的基础上，即以该X轴最优位置为起点，开始寻找Y轴上的最优位置，一旦找到了Y轴上的最优位置，则该位置就是整个X-Y平面的最优位置。)
6)无人机在每个迭代时隙增加一个第二扰动步长Δy，并设置第二扰动步长阈值Δthy，用坐标表示为Δy＝(0，y0，0)。Δy为本算法第二阶段的初始扰动步长。
7)无人机计算它的下一个位置
Figure PCTCN2015096741-appb-000019
并移动到该位置。
8)目的端测量新的接收信号的通信性能Q(n)，并且更新其内存中的最佳接收信号通信性能，更新规则为Qbest(n+1)＝max(Qbest(n)，Q(n))。随后目的端反馈一比特信息(假设该比特在传输过程中无误码)给无人机，以表明此次通信性能是否提高。
9)无人机根据反馈回来的一比特信息，更新自己的最佳已知位置R2(n)，更新规则如下：(CN表示连续负反馈计数器，连续负反馈计数器阈值CT＝2；扰动步长下降因子RD，取经验值。)
if Q(n)＞Qbest(n)
R2(n+1)＝R2(n)+Δy
CN＝0；
else
R2(n+1)＝R2(n)
CN＝CN+1；
Δy＝-Δy；
if CN≥CT
Δy＝Δy·RD；
CN＝0；
end
end
10)无人机判断是否停止第二阶段搜寻，若第二扰动步长Δy小于等于预定阈值Δthy，则停止第二阶段搜寻，整个搜寻过程结束，无人机最后所处的位置即为所找到的最优中继位置；若扰动步长Δy大于预定阈值Δthy，则返回步骤6)，继续第二阶段的搜寻。
无人机最佳中继位置搜寻仿真如图4所示：
初始步长x0＝50，y0＝50；连续负反馈计数器阈值CT＝2；扰动步长下降因子 RD＝0.5；第一扰动步长阈值Δthx＝0.0001；第二扰动步长阈值Δthy＝0.0001。
(1)以信噪比为基准表示通信性能的好坏，也就是公式(4)
源端(S)的位置坐标：(xs，ys，zs)＝(100，-100，1)；
目的端(D)的位置坐标：(xd，yd，zd)＝(-100，100，1)；
无人机的高度固定：30m；
图4中，X轴表示横坐标，Y轴表示纵坐标，Z轴表示与坐标点相对应的信噪比γend。
(2)以信噪比为基准表示通信性能的好坏，也就是公式(4)
源端(S)的位置坐标：(xs，ys，zs)＝(100，-100，1)；
目的端(D)的位置坐标：(xd，yd，zd)＝(-100，100，1)；
无人机的起始位置坐标(高度固定在30m)：R(1)＝(x1，y1，z1)＝(-100，-100，30)
图5中横轴表示无人机搜寻最佳位置过程中花费的时隙数，纵轴表示端到端信噪比γend，可以看到无人机在起始位置R(1)时的信噪比为-0.7352dB，搜寻到第12个时隙(即R(12)位置)时的信噪比为0.4831dB，在第20个时隙停止第一阶段的搜寻并启动第二阶段搜寻，在第37个时隙(即R(37)位置)时的信噪比为2.187dB，找到了图4中的极大值点，也即找到了最佳中继位置，在第40个时隙结束第二阶段搜寻。
本发明属于无线通信技术领域，可以被应用来搜寻三维空间的全局最优中继位置，提高中继通信的性能。潜在的应用场景有：临时通信系统的搭建、灾害现场的通信连接等。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种基于步长阈值机制的最佳中继位置搜寻方法，其特征在于，所述最佳中继位置搜寻方法的步骤包括：
    步骤A，单个移动中继在测试场所的固定高度平面内的任意位置，接收来自源端发送的测试信号并进行放大，然后将放大的测试信号转发至目的端；
    步骤B，目的端根据接收到的信号计算通信性能，并根据计算的通信性能与保存的已知最佳接收信号通信性能的比较结果生成单比特信息反馈至所述移动中继；所述单比特信息包括性能是否提高的信息，所述已知最佳接收信号通信性能为已测试的最好通信性能；
    步骤C，所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，重复步骤A-C，直至找到最佳中继位置。
  2. 如权利要求1所述的最佳中继位置搜寻方法，其特征在于，步骤A中，移动中继位于测试场所的固定高度平面内的任意位置开始测试，以起始位置为初始化位置，将所述初始化位置记录为已知最佳位置并存在自身的内存中，然后接收来自源端发送的测试信号并进行放大，将放大的测试信号转发至目的端。
  3. 如权利要求2所述的最佳中继位置搜寻方法，其特征在于，步骤B中，目的端根据接收的信号计算通信性能，然后将所述通信性能与自身内存保存的已知最佳接收信号的通信性能进行比较，根据比较结果更新内存中保存的已知最佳接收信号的通信性能，并生成单比特信息反馈至所述移动中继。
  4. 如权利要求3所述的最佳中继位置搜寻方法，其特征在于，步骤C具体包括：
    步骤C1，所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，然后返回步骤A，继续进行第一阶段位置搜寻，直至确定第一阶段最佳中继位置然后结束第一阶段位置搜寻；
    步骤C2，第一阶段位置搜寻结束之后，移动中继以所述第一阶段最佳中继位置为起点开始进行第二阶段位置搜寻，直至确定第二阶段最佳中继位置，所 述第二阶段最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置。
  5. 如权利要求4所述的最佳中继位置搜寻方法，其特征在于，步骤C1具体包括：
    步骤C11，所述移动中继记录其已知最佳位置，并设置第一扰动步长，所述已知最佳位置用R1(n)表示，n表示第n个时隙；
    步骤C12，所述移动中继根据第一扰动步长计算下一时刻位置并移动到该下一时刻位置，返回步骤A，接收来自源端发射的测试信号并放大转发至目的端；
    以
    Figure PCTCN2015096741-appb-100001
    表示所述下一时刻位置，以Δx表示所述第一扰动步长，则：
    Figure PCTCN2015096741-appb-100002
    所述第一扰动步长的初始值预设为Δx＝(x0，0，0)；
    步骤C13，目的端计算新的接收信号的通信性能，根据计算出的通信性能与保存的已知最佳接收信号的通信性能进行比较，若新的通信性能优于已知最佳接收信号的通信性能，则将所述新的接收信号的通信性能保存为已知最佳接收信号的通信性能，然后目的端反馈单比特信息给所述移动中继；若新的通信性能比已知最佳接收信号的通信性能差，则保存的已知最佳接收信号的通信性能不变，然后目的端反馈单比特信息给所述移动中继；
    步骤C14，所述移动中继对所述单比特信息进行判断；
    步骤C15，在判断为接收信号性能提升时，将连续负反馈计数器清零，更新保存的已知最佳中继位置，并判断是否结束第一阶段位置搜寻；
    步骤C16，在判断为接收信号性能未提升时，移动中继返回上一时隙的位置，同时连续负反馈计数器加1，第一扰动步长修改为上一时隙的第一扰动步长的相反数，并判断连续负反馈计数器是否达到预设的连续负反馈阈值；所述连续负反馈阈值设定为2；
    步骤C17，若判断步骤C16中的连续负反馈计数器达到预设的连续负反馈阈值，则连续负反馈计数器清零并减小第一扰动步长，然后判断是否结束第一阶段位置搜寻；
    步骤C18，若第一扰动步长小于等于预设的第一扰动步长阈值，则结束第一阶段位置搜寻，并将保存的已知最佳中继位置作为第一阶段最佳中继位置；
    若扰动步长大于预设的第一扰动步长阈值，则返回步骤C12。
  6. 如权利要求4所述的最佳中继位置搜寻方法，其特征在于，步骤C2具体包括：
    步骤C21，移动中继根据所述第一阶段最佳中继位置为起点，设置第二扰动步长；
    步骤C22，所述移动中继根据第二扰动步长计算下一时刻位置并移动到该下一时刻位置，继续接收来自源端发射的测试信号并放大转发至目的端；
    以
    Figure PCTCN2015096741-appb-100003
    表示下一时刻位置，以R2(n)表示已知最佳中继位置，以Δy表示所述第二扰动步长，则：
    Figure PCTCN2015096741-appb-100004
    所述第二扰动步长的初始值预设为则Δy＝(0，y0，0)；
    步骤C23，目的端计算新的接收信号的通信性能，根据计算出的通信性能与保存的已知最佳接收信号的通信性能进行比较，若新的通信性能优于已知最佳接收信号的通信性能，则将所述新的接收信号的通信性能保存为已知最佳接收信号的通信性能，然后目的端反馈单比特信息给所述移动中继；若新的通信性能比已知最佳接收信号的通信性能差，则保存的已知最佳接收信号的通信性能不变，然后目的端反馈单比特信息给所述移动中继；
    步骤C24，所述移动中继对所述单比特信息进行判断；
    步骤C25，在判断为接收信号性能提升时，将连续负反馈计数器清零，更新保存的已知最佳中继位置，并判断是否结束第二阶段位置搜寻；
    步骤C26，在判断为接收信号性能未提升时，移动中继返回上一时隙的位置，同时连续负反馈计数器加1，第二扰动步长修改为上一时隙的第二扰动步长的相反数，并判断连续负反馈计数器是否达到预设的连续负反馈阈值；所述连续负反馈阈值设定为2；
    步骤C27，若判断步骤C26中的连续负反馈计数器达到预设的连续负反馈 阈值，则连续负反馈计数器清零并减小第二扰动步长，然后判断是否结束第二阶段位置搜寻；
    步骤C28，若第二扰动步长小于等于预设的第二扰动步长阈值，则结束第二阶段位置搜寻，并将保存的已知最佳中继位置作为第二阶段的最佳中继位置，所述第二阶段的最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置；
    若扰动步长大于预设的第二扰动步长阈值，则返回步骤C22。
  7. 一种基于步长阈值机制的最佳中继位置搜寻系统，其特征在于，所述最佳中继位置搜寻系统包括源端、单个移动中继和目的端；
    所述源端，用于发送测试信号至所述移动中继；
    所述移动中继，用于在测试场所的任意位置，接收来自源端发送的测试信号并进行放大，然后将放大测试信号转发至所述目的端；
    所述目的端，用于根据接收到的信号计算通信性能，并根据计算的通信性能与保存的已知最佳接收信号通信性能的比较结果生成单比特信息反馈至所述移动中继；所述单比特信息包括性能是否提高的信息，所述已知最佳接收信号通信性能为已测试的最好通信性能；所述移动中继根据反馈的单比特信息计算下一时刻位置并移动至该下一时刻位置，继续将源端传输的测试信号进行放大后转发至所述目的端，直至找到最佳中继位置。
  8. 如权利要求7所述的最佳中继位置搜寻系统，其特征在于，移动中继位于测试场所的固定高度平面内的任意位置开始测试，以起始位置为初始化位置，将所述初始化位置记录为已知最佳位置并存在自身的内存中，然后接收来自源端发送的测试信号并进行放大，将放大的测试信号转发至目的端。
  9. 如权利要求8所述的最佳中继位置搜寻系统，其特征在于，目的端根据接收到的信号计算通信性能，然后将所述通信性能与自身内存保存的已知最佳接收信号的通信性能进行比较，根据比较结果更新内存中保存的已知最佳接收信号的通信性能，并生成单比特信息反馈至所述移动中继。
  10. 如权利要求9所述的最佳中继位置搜寻系统，其特征在于，所述搜寻系统具体还用于：
    首先，所述移动中继根据反馈的单比特信息进行计算，根据计算结果移动至下一中继位置，然后进行第一阶段位置搜寻，直至确定第一阶段最佳中继位置然后结束第一阶段位置搜寻；
    最后，第一阶段位置搜寻结束之后，移动中继以所述第一阶段最佳中继位置为起点开始进行第二阶段位置搜寻，直至确定第二阶段最佳中继位置，所述第二阶段最佳中继位置即为最终的在固定高度平面内的全局最佳中继位置。
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