CN113194484A - Large-scale access method based on inter-satellite cooperation - Google Patents
Large-scale access method based on inter-satellite cooperation Download PDFInfo
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Abstract
The invention discloses a large-scale access method based on inter-satellite cooperation. And a plurality of low-orbit satellites adopt a multi-beam technology at the same time, so that the whole system capacity is increased. Each satellite covers multiple regions, satellite users within each region share the same beam, and overlapping coverage areas may exist between adjacent satellites, thereby generating inter-satellite interference. Each satellite obtains the channel state information of each user by utilizing channel estimation, adjacent satellites share the channel state information of the users in the overlapped area through inter-satellite links, then the transmitted signal of each wave beam is subjected to superposition coding according to the channel information, and finally the signal subjected to superposition coding is transmitted out through an antenna. After receiving the signals, the users firstly decode the user signals with weak channel gain in the beam area, remove the signals of the users and finally decode the signals of the users. The invention provides an effective wireless access method for realizing space-based large-scale information network.
Description
Technical Field
The invention relates to the field of wireless communication, in particular to a large-scale access method based on inter-satellite cooperation.
Background
In recent years, fifth generation (5G) mobile communication networks are gradually popularized, 5G applications and technical innovations are continuously emerging, and the service capacity of the terrestrial communication networks reaches an unprecedented peak. However, there is a long movement away from the vision of "accessing a communication network anytime and anywhere", such as in many remote areas, such as deserts, mountains and oceans, where the communication network still does not have complete coverage, which allows many correspondents to shift their eyes from a ground-based communication network to a space-based communication network.
The service area of a terrestrial network typically does not achieve 100% coverage around the globe due to geographical location and economic cost, among other factors. In extreme areas, the difficulty and cost of deploying communication devices is enormous. Space-based communication networks based on low-orbit satellites can avoid these problems, and thus attract unprecedented attention. The low-orbit satellite has the characteristics of low cost and small time delay, and after a plurality of low-orbit satellites are jointly networked, user information in a certain area can be transmitted to any corner on the earth through an inter-satellite link, and a communication network covers the whole world and forms effective complementation with a ground network. Therefore, multi-satellite networks based on inter-satellite cooperation will be an essential part of future communication networks.
In addition, future wireless networks will need to support simultaneous access of a large number of internet of things devices. In the currently widely adopted orthogonal multiple access technology, such as Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA), one radio resource block can only be allocated to one mobile terminal, and the requirement for accessing a large amount of internet of things devices cannot be met. In this case, a non-orthogonal multiple access technology has been studied in a large amount. The non-orthogonal technology is generally divided into two categories of power domain and code domain, and the power domain non-orthogonal multiple access technology is convenient to realize, so that the power domain non-orthogonal multiple access technology is adopted in the text. The non-orthogonal multi-access technology mainly utilizes superposition coding of a transmitting end and serial interference cancellation of a receiving end to realize efficient multi-user access. Due to the limitation of serial interference performance, the bit error rate is greatly increased when the number of access users is too large. Therefore, it is necessary to divide the users into a plurality of clusters (i.e., different satellite beam coverage areas) and perform serial interference cancellation only in each cluster, thereby effectively reducing the computational complexity of the users. However, new inter-cluster interference may occur between different clusters, and inter-network interference may also occur between different satellite networks due to the same frequency band.
In order to further improve the performance of the non-orthogonal multiple access technology, various types of interference must be effectively suppressed, i.e. an effective beamforming technology needs to be adopted.
Disclosure of Invention
The invention aims to solve the problem that the coverage area of the existing ground communication network is limited, designs a multi-satellite communication network to provide an efficient access method for future wireless communication, and further provides a large-scale access method based on inter-satellite cooperation. The invention combines the non-orthogonal multiple access technology with the multi-satellite communication network to establish a large-scale space-based information network, and can effectively make up for the deficiency of the ground-based communication network, thereby further improving the capability of the current communication system and realizing the global coverage and supporting the access of mass equipment.
The invention adopts the following specific technical scheme:
a large-scale access method based on inter-satellite cooperation comprises the following steps:
1) a first satellite and a second satellite collaboratively serve a plurality of users, the satellite users belong to different satellite beam coverage areas according to the areas where the satellite users are located, the first satellite has M satellite beams, and the second satellite has L satellite beams; the first satellite and the second satellite have A wave beams covering an overlapping area, wherein B users in the overlapping area belong to the first satellite, the second satellite generates interference to signals of the B users in the overlapping area, and (A-B) users in the overlapping area belong to the second satellite, and the first satellite generates interference to signals of the (A-B) users in the overlapping area;
2) the ground gateway station sends the user channel state information to the first satellite or the second satellite through a feedback link, and the first satellite obtains the user channel state informationObtaining the nth satellite user UE in the mth satellite area1,m,nChannel state information h of1,m,nThe second satellite obtains the s satellite user UE in the l satellite area2,l,sChannel state information h of2,l,sAnd the user channel state information of the overlapping area is transmitted to the adjacent satellite through the inter-satellite link; m is an element of [0, M ]],l∈[0,L];
3) The first satellite is a satellite user UE1,m,nSignal x of1,m,nPower allocation factor alpha in allocation region1,m,nAnd a transmission beam w is designed for the mth satellite region1,mThe second satellite is a satellite user UE2,l,sSignal x of2,l,sPower allocation factor alpha in allocation region2,l,sAnd a transmission beam w is designed for the ith satellite region2,l;
4) According to the power division factor alpha1,m,,nThe first satellite performs superposition coding on the signals of all satellite users in the satellite area and then transmits a beam w1,mBeamforming the superposition coded signal to generate a broadcast signal x1(ii) a The second satellite performs superposition coding on the signals of all satellite users in the satellite area and then transmits a beam w2,lBeamforming the superposition coded signal to generate a broadcast signal x2(ii) a Then each satellite broadcasts the respective broadcast signal to the respective user through a downlink channel;
5) after receiving the signals transmitted by the satellite, each satellite user performs serial interference cancellation on the user signals in the same area, and then decodes the signals of the user.
Preferably, the beam design method in step 3) is:
a) initializing a transmit beam WhereinAndare all feasible points in the previous iteration, P1,maxIs the maximum transmission power, P, of the first satellite2,maxIs the maximum transmit power of the second satellite; power allocation factor in first satellite regionNmRepresenting the total number of users in the mth satellite area, i representing the ith user in the mth wave beam of the first satellite; power allocation factor in the second satellite regionSlRepresenting the total number of users in the ith satellite area, wherein i represents the ith user of the ith beam of the second satellite;
b) due to the rapid change of satellite channels, the channel state information acquired by each satellite has phase deviation with an actual channel; the actual user channel state information of the first satellite isThe second satellite actual user channel state information isInterference channel of first satellite to second satellite user in overlapping area The interference channel of the second satellite to the first satellite user in the overlapping region isWherein all superscripts j represent imaginary numbers;
for the users of the first satellite:
A1,m,n=real(Z1,m,n),B1,m,n=imag(Z1,m,n),E1,m,n=f1(A1,m,n),e1,m,n=f2(B1,m,n),A2,m,n=real(Z2,m,n),B2,m,n=imag(Z2,m,n),E2,m,n=f1(A2,m,n),e2,m,n=f2(B2,m,n),
for the users of the second satellite:
A2,l,s=real(Z2,l,s),B2,l,s=imag(Z2,l,s),E2,l,s=f1(A2,l,s),e2,l,s=f2(B2,l,s),A1,l,s=real(Z1,l,s),B1,l,s=imag(Z1,l,s),E1,l,s=f1(A1,l,s),e1,l,s=f2(B1,l,s),
for a certain satellite user, the subscript j represents the jth beam coverage area of the satellite, and i represents the ith user in a certain beam coverage area of the satellite;
wherein the subscript [1, m, n ]]Representing a first satellite user parameter, i.e., representing an nth user within an mth satellite beam region of the first satellite; subscript [2, l, s ]]Representing a second satellite user parameter, i.e., representing an s-th satellite user within an l-th satellite beam area of the second satellite; subscript [2, m, n ]]Representing a parameter acquired by a first satellite user in an overlapping area by a second satellite; subscript [1, l, s ]]Representing a parameter acquired by a first satellite to a second satellite user in an overlapping area; f. of1,m,n,f2,m,n,f1,l,sAnd f2,l,sAre all intermediate parameters;andrepresenting the noise variance of the first satellite user and the second satellite user respectively;andrespectively obtaining imperfect channel state information of a satellite channel of a first satellite user and imperfect channel state information of an interference channel of the first satellite to a second satellite user in an overlapping area;andrespectively obtaining imperfect channel state information of a satellite channel of a second satellite user and imperfect channel state information of an interference channel of the second satellite to a first satellite user in an overlapping area; theta1,m,nAnd theta1,l,sThe phase errors of a first satellite user satellite channel and a first satellite to a second satellite user interference channel in an overlapping area are respectively; theta2,l,sAnd theta2,m,nThe phase errors of a second satellite user satellite channel and a second satellite to a first satellite user interference channel in an overlapping area are respectively;andthe covariance matrix of the phase errors of the satellite channel of the first satellite user and the interference channel of the second satellite user in the overlapping area of the first satellite are respectively;andthe covariance matrix of the phase errors of the satellite channel of the first satellite user and the interference channel of the second satellite user in the overlapping area of the first satellite are respectively; w1,m=w1,mw1,m HIs a first satellite beam matrix, W2,l=w2,lw2,l HIs a second satellite beam matrix, P1,kAnd P2,kThe days of the first satellite and the second satellite respectivelyLine power limitation, first satellite having K1 antennas, second satellite having K2 antennas, Z[i,j]Represents the ith row and jth column element of matrix Z,the representative matrix T is a semi-positive definite matrix; eta1,m,nAnd η2,l,sThe residual interference coefficient, gamma, generated by imperfect decoding caused by successive interference cancellation technique when the first satellite user and the second satellite user decode respectively1,m,nAnd gamma2,l,sMinimum signal to interference plus noise ratio requirements, p, for the first satellite user and the second satellite user, respectively1,m,nAnd p2,l,sThe interruption probability that the first satellite user and the second satellite user can not meet the communication signal-to-interference-and-noise ratio requirement is respectively, a1,m,n,b1,m,nAnd a2,l,s,b2,l,sIs an auxiliary parameter, E1,m,n、Z1,m,n、T1,m,n、A1,m,n、B1,m,n、e1,m,n、e1,l,sAnd E2,m,n、Z2,l,s、T2,l,s、A2,l,s、B2,l,s、e2,m,n、e2,l,sAre all intermediate variables; tr (Z) is a trace of the matrix Z, H in the upper right corner of the variable represents a Hermite transpose, and 2 in the upper right corner of the variable represents a square; f. of1(A) And f2(B) Is two linear transformations, of whichK represents the number of columns of the matrix; δ (m, n) and δ (l, s) take values of 0 or 1, wherein 1 represents that the nth user in the mth beam of the first satellite is interfered by the second satellite or the mth user in the mth beam of the second satellite is interfered by the first satellite, and 0 represents that the user is not interfered; i isK1And IK2Is an identity matrix, with subscript K denoting the dimension;
solving the minimum value of each transmitting power by using an iterative method, wherein the minimum value is Each iteration obtains corresponding W1,mAnd W2,lUp to W1,mAnd W2,lWhen the rank approaches 1, a singular value decomposition method is utilized to obtain a final wave beam w1,mAnd w2,lAnd in each iteration process, an interior point method is adopted or a CVX tool package is directly called to solve.
Further, the step 4) specifically comprises: the total signal transmitted by the first satellite for all users isWherein is alpha1,m,nAllocating a factor, w, to the power in the beam region1,mIs the transmission beam of the m-th region, x1,m,nIs the signal of the nth user in the mth satellite beam area; the total signal transmitted by the second satellite for all users isWherein alpha is2,l,sIs the power allocation factor, w, within the beam region2,lIs a transmission beam in the l region, x2,l,sIs the signal of the s-th user in the area of the l-th satellite beam.
Further, the method for canceling the serial interference in step 5) includes: any satellite user firstly decodes the signals of users with weaker channel gain than the satellite user in the same area, subtracts the signals from the received signals, and finally decodes the satellite user's signal.
Compared with the prior art, the invention has the following beneficial effects:
the large-scale access method based on inter-satellite cooperation provided by the invention overcomes the defect that global coverage cannot be realized by a land Internet of things, makes global communication seamless connection possible, and has the advantages of high spectrum efficiency, capability of effectively inhibiting interference, actual and reliable scene and the like.
Drawings
FIG. 1 is a block diagram of the method of the present invention;
FIG. 2 is a graphical comparison of the minimum power required for the method of the present invention at different phase error magnitudes;
fig. 3 is a diagram showing a comparison of the minimum power required in the method of the present invention and the orthogonal access method (time division multiplexing).
Detailed Description
The invention will be further elucidated and described with reference to the drawings and the detailed description. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.
The system block diagram of the large-scale access method based on inter-satellite cooperation is shown in fig. 1, and a plurality of low-orbit satellites simultaneously adopt the multi-beam technology to increase the whole system capacity. Each satellite covers multiple regions, satellite users within each region share the same beam, and overlapping coverage areas may exist between adjacent satellites, thereby generating inter-satellite interference. Each satellite obtains the channel state information of each user by utilizing channel estimation, adjacent satellites share the channel state information of users in an overlapped area through inter-satellite links, then superposition coding is carried out on the transmitting signal of each wave beam according to the channel information, and finally the signal after superposition coding is transmitted out through a wave beam forming network. After receiving the signals, the users firstly decode the user signals with weak channel gain in the beam area, remove the signals of the users and finally decode the signals of the users.
Wherein, the satellite 1 has K1Root antenna, satellite 2 having K2And 1 antenna is configured for each satellite user. Users in different beam areas share one beam, so that successive interference cancellation is performed in respective areas, thereby reducing the complexity of successive interference cancellation. The satellite earth station receives the training sequence from the user to estimatePartial channel state information. Based on the obtained partial channel state information, each satellite designs a robust transmission beam for each user signal in each region. After receiving the signal, the user performs serial interference cancellation on the signal in the area to further reduce interference and improve the performance of the system.
The specific technical scheme adopted by the invention comprises the following steps:
1) a first satellite and a second satellite collaboratively serve a plurality of users, the satellite users belong to different satellite beam coverage areas according to the areas where the satellite users are located, the first satellite has M satellite beams, and the second satellite has L satellite beams; the first satellite and the second satellite have A wave beams covering an overlapping area, wherein B users in the overlapping area belong to the first satellite, the second satellite generates interference to signals of the B users in the overlapping area, and (A-B) users in the overlapping area belong to the second satellite, and the first satellite generates interference to signals of the (A-B) users in the overlapping area;
2) the ground gateway station sends the user channel state information to the first satellite or the second satellite through a feedback link, and the first satellite obtains the nth satellite user UE in the mth satellite area1,m,nChannel state information h of1,m,nThe second satellite obtains the s satellite user UE in the l satellite area2,l,sChannel state information h of2,l,sAnd the user channel state information of the overlapping area is transmitted to the adjacent satellite through the inter-satellite link; wherein M is [0, M ]],l∈[0,L];
3) The first satellite is a satellite user UE1,m,nSignal x of1,m,nPower allocation factor alpha in allocation region1,m,nAnd a transmission beam w is designed for the mth satellite region1,mThe second satellite is a satellite user UE2,l,sSignal x of2,l,sPower allocation factor alpha in allocation region2,l,sAnd a transmission beam w is designed for the ith satellite region2,l。
In practical application, the beam design method in step 3) may adopt the following method:
a) initializing a transmit beam WhereinAndare all feasible points in the previous iteration, P1,maxIs the maximum transmission power, P, of the first satellite2,maxIs the maximum transmit power of the second satellite; power allocation factor in first satellite regionNmRepresenting the total number of users in the mth satellite area, i representing the ith user in the mth wave beam of the first satellite; power allocation factor in the second satellite regionSlRepresenting the total number of users in the ith satellite area, wherein i represents the ith user of the ith beam of the second satellite;
b) due to the rapid change of satellite channels, the channel state information acquired by each satellite has phase deviation with an actual channel; the actual user channel state information of the first satellite isThe second satellite actual user channel state information isInterference channel of first satellite to second satellite user in overlapping area The interference channel of the second satellite to the first satellite user in the overlapping region isWherein all superscripts j represent imaginary numbers;
for the user of the first satellite, the following is specified:
A1,m,n=real(Z1,m,n),B1,m,n=imag(Z1,m,n),E1,m,n=f1(A1,m,n),e1,m,n=f2(B1,m,n),A2,m,n=real(Z2,m,n),B2,m,n=imag(Z2,m,n),E2,m,n=f1(A2,m,n),e2,m,n=f2(B2,m,n),
for the user of the second satellite, the following is specified:
A2,l,s=real(Z2,l,s),B2,l,s=imag(Z2,l,s),E2,l,s=f1(A2,l,s),e2,l,s=f2(B2,l,s),A1,l,s=real(Z1,l,s),B1,l,s=imag(Z1,l,s),E1,l,s=f1(A1,l,s),e1,l,s=f2(B1,l,s),
for a certain satellite user, the subscript j represents the jth beam coverage area of the satellite, and i represents the ith user in a certain beam coverage area of the satellite;
wherein the subscript [1, m, n ]]Representing a first satellite user parameter, i.e., representing an nth user within an mth satellite beam region of the first satellite; subscript [2, l, s ]]Representing a second satellite user parameter, i.e., representing an s-th satellite user within an l-th satellite beam area of the second satellite; subscript [2, m, n ]]Representing a parameter acquired by a first satellite user in an overlapping area by a second satellite; subscript [1, l, s ]]Representing a parameter acquired by a first satellite to a second satellite user in an overlapping area; f. of1,m,n,f2,m,n,f1,l,sAnd f2,l,sAre all intermediate parameters;andrepresenting the noise variance of the first satellite user and the second satellite user respectively;andrespectively obtaining imperfect channel state information of a satellite channel of a first satellite user and imperfect channel state information of an interference channel of the first satellite to a second satellite user in an overlapping area;andrespectively obtaining imperfect channel state information of a satellite channel of a second satellite user and imperfect channel state information of an interference channel of the second satellite to a first satellite user in an overlapping area; theta1,m,nAnd theta1,l,sThe phase errors of a first satellite user satellite channel and a first satellite to a second satellite user interference channel in an overlapping area are respectively; theta2,l,sAnd theta2,m,nThe phase errors of a second satellite user satellite channel and a second satellite to a first satellite user interference channel in an overlapping area are respectively;andthe covariance matrix of the phase errors of the satellite channel of the first satellite user and the interference channel of the second satellite user in the overlapping area of the first satellite are respectively;andare respectively the firstA covariance matrix of phase errors of a satellite user satellite channel and a second satellite user interference channel in the overlap region by the first satellite; w1,m=w1,mw1,m HIs a first satellite beam matrix, W2,l=w2,lw2,l HIs a second satellite beam matrix, P1,kAnd P2,kAntenna power limits for a first satellite having K1 antennas and a second satellite having K2 antennas, Z[i,j]Represents the ith row and jth column element of matrix Z,the representative matrix T is a semi-positive definite matrix; eta1,m,nAnd η2,l,sThe residual interference coefficient, gamma, generated by imperfect decoding caused by successive interference cancellation technique when the first satellite user and the second satellite user decode respectively1,m,nAnd gamma2,l,sMinimum signal to interference plus noise ratio requirements, p, for the first satellite user and the second satellite user, respectively1,m,nAnd p2,l,sThe interruption probability that the first satellite user and the second satellite user can not meet the communication signal-to-interference-and-noise ratio requirement is respectively, a1,m,n,b1,m,nAnd a2,l,s,b2,l,sIs an auxiliary parameter, E1,m,n、Z1,m,n、T1,m,n、A1,m,n、B1,m,n、e1,m,n、e1,l,sAnd E2,m,n、Z2,l,s、T2,l,s、A2,l,s、B2,l,s、e2,m,n、e2,l,sAre all intermediate variables; tr (Z) is a trace of the matrix Z, H in the upper right corner of the variable represents a Hermite transpose, and 2 in the upper right corner of the variable represents a square; f. of1(A) And f2(B) Is two linear transformations, whichInK represents the number of columns of the matrix; δ (m, n) and δ (l, s) take values of 0 or 1, wherein 1 represents that the nth user in the mth beam of the first satellite is interfered by the second satellite or the mth user in the mth beam of the second satellite is interfered by the first satellite, and 0 represents that the user is not interfered; i isK1And IK2Is an identity matrix, with subscript K denoting the dimension;
solving the minimum value of each transmitting power by using an iterative method, wherein the minimum value is Each iteration obtains corresponding W1,mAnd W2,lUp to W1,mAnd W2,lWhen the rank approaches 1, a singular value decomposition method is utilized to obtain a final wave beam w1,mAnd w2,lAnd in each iteration process, an interior point method is adopted or a CVX tool package is directly called to solve.
4) According to the power division factor alpha1,m,nThe first satellite performs superposition coding on the signals of all satellite users in the satellite area and then transmits a beam w1,mBeamforming the superposition coded signal to generate a broadcast signal x1(ii) a The second satellite performs superposition coding on the signals of all satellite users in the satellite area and then transmits a beam w2,lBeamforming the superposition coded signal to generate a broadcast signal x2(ii) a Each satellite then broadcasts a respective broadcast signal to a respective user via a downlink channel.
In practical application, the following method can be adopted in the step 4): the total signal transmitted by the first satellite for all users isWherein is alpha1,m,nAllocating a factor, w, to the power in the beam region1,mIs the transmission beam of the m-th region, x1,m,nIs the signal of the nth user in the mth satellite beam area; the total signal transmitted by the second satellite for all users isWherein alpha is2,l,sIs the power allocation factor, w, within the beam region2,lIs a transmission beam in the l region, x2,l,sIs the signal of the s-th user in the area of the l-th satellite beam.
5) After receiving the signals transmitted by the satellite, each satellite user performs serial interference cancellation on the user signals in the same area, and then decodes the signals of the user.
In practical application, the method for canceling the serial interference in step 5) may specifically adopt the following steps: any satellite user firstly decodes the signals of users with weaker channel gain than the satellite user in the same area, subtracts the signals from the received signals, and finally decodes the satellite user's signal.
Computer simulation shows that, as shown in fig. 2, the large-scale access method based on inter-satellite cooperation provided by the invention can effectively resist the interference caused by imperfect serial interference cancellation. In addition, fig. 3 shows that the method of the present invention is sensitive to the outage probability, and when the power required for the outage probability is much larger than the outage probability, a nonlinear relationship exists between the terminal probability and the power consumption. Therefore, the large-scale access method based on inter-satellite cooperation provided by the invention provides a feasible and effective large-scale user access method for a high-efficiency information network covering the whole world.
Claims (4)
1. A large-scale access method based on inter-satellite cooperation is characterized by comprising the following steps:
1) a first satellite and a second satellite collaboratively serve a plurality of users, the satellite users belong to different satellite beam coverage areas according to the areas where the satellite users are located, the first satellite has M satellite beams, and the second satellite has L satellite beams; the first satellite and the second satellite have A wave beams covering an overlapping area, wherein B users in the overlapping area belong to the first satellite, the second satellite generates interference to signals of the B users in the overlapping area, and (A-B) users in the overlapping area belong to the second satellite, and the first satellite generates interference to signals of the (A-B) users in the overlapping area;
2) the ground gateway station sends the user channel state information to the first satellite or the second satellite through a feedback link, and the first satellite obtains the nth satellite user UE in the mth satellite area1,m,nChannel state information h of1,m,nThe second satellite obtains the s satellite user UE in the l satellite area2,l,sChannel state information h of2,l,sAnd the user channel state information of the overlapping area is transmitted to the adjacent satellite through the inter-satellite link; m is an element of [0, M ]],l∈[0,L];
3) The first satellite is a satellite user UE1,m,nSignal x of1,m,nPower allocation factor alpha in allocation region1,m,nAnd a transmission beam w is designed for the mth satellite region1,mThe second satellite is a satellite user UE2,l,sSignal x of2,l,sPower allocation factor alpha in allocation region2,l,sAnd a transmission beam w is designed for the first satellite region2,l;
4) According to the power division factor alpha1,m,nThe first satellite performs superposition coding on the signals of all satellite users in the satellite area and then transmits a beam w1,mBeamforming the superposition coded signal to generate a broadcast signal x1(ii) a The second satellite performs superposition coding on the signals of all satellite users in the satellite area and then transmits a beam w2,lBeamforming the superposition coded signal to generate a broadcast signal x2(ii) a Then each satellite broadcasts the respective broadcast signal to the respective user through a downlink channel;
5) after receiving the signals transmitted by the satellite, each satellite user performs serial interference cancellation on the user signals in the same area, and then decodes the signals of the user.
2. The massive access method based on inter-satellite cooperation according to claim 1, wherein the beam design method in step 3) is:
a) initializing a transmit beam WhereinAndare all feasible points in the previous iteration, P1,maxIs the maximum transmission power, P, of the first satellite2,maxIs the maximum transmit power of the second satellite; power allocation factor in first satellite regionNmRepresenting the total number of users in the mth satellite area, i representing the ith user in the mth wave beam of the first satellite; power allocation factor in the second satellite regionSlRepresenting the total number of users in the ith satellite area, wherein i represents the ith user of the ith beam of the second satellite;
b) due to the rapid change of satellite channels, the channel state information acquired by each satellite has phase deviation with an actual channel; the actual user channel state information of the first satellite isThe second satellite actual user channel state information isInterference channel of first satellite to second satellite user in overlapping area The interference channel of the second satellite to the first satellite user in the overlapping region isWherein all superscripts j represent imaginary numbers;
for the users of the first satellite:
A1,m,n=real(Z1,m,n),B1,m,n=imag(Z1,m,n),E1,m,n=f1(A1,m,n),e1,m,n=f2(B1,m,n),A2,m,n=real(Z2,m,n),B2,m,n=imag(Z2,m,n),E2,m,n=f1(A2,m,n),e2,m,n=f2(B2,m,n),
for the users of the second satellite:
A2,l,s=real(Z2,l,s),B2,l,s=imag(Z2,l,s),E2,l,s=f1(A2,l,s),e2,l,s=f2(B2,l,s),A1,l,s=real(Z1,l,s),B1,l,s=imag(Z1,l,s),E1,l,s=f1(A1,l,s),e1,l,s=f2(B1,l,s),
b2,l,s≥0,W2,l≥,[∑lW2,l]k,k≤P2,k(ii) a For a certain satellite user, the subscript j represents the jth beam coverage area of the satellite, and i represents the ith usage in a certain beam coverage area of the satelliteA household;
wherein the subscript [1, m, n ]]Representing a first satellite user parameter, i.e., representing an nth user within an mth satellite beam region of the first satellite; subscript [2, l, s ]]Representing a second satellite user parameter, i.e., representing an s-th satellite user within an l-th satellite beam area of the second satellite; subscript [2, m, n ]]Representing a parameter acquired by a first satellite user in an overlapping area by a second satellite; subscript [1, l, s ]]Representing a parameter acquired by a first satellite to a second satellite user in an overlapping area; f. of1,m,n,f2,m,n,f1,l,sAnd f2,l,sAre all intermediate parameters;andrepresenting the noise variance of the first satellite user and the second satellite user respectively;andrespectively obtaining imperfect channel state information of a satellite channel of a first satellite user and imperfect channel state information of an interference channel of the first satellite to a second satellite user in an overlapping area;andrespectively obtaining imperfect channel state information of a satellite channel of a second satellite user and imperfect channel state information of an interference channel of the second satellite to a first satellite user in an overlapping area; theta1,m,nAnd theta1,l,sThe phase errors of a first satellite user satellite channel and a first satellite to a second satellite user interference channel in an overlapping area are respectively; theta2,l,sAnd theta2,m,nRespectively, a second satellite userPhase errors of the satellite channel and a second satellite to a first satellite user interference channel in the overlapping region;andthe covariance matrix of the phase errors of the satellite channel of the first satellite user and the interference channel of the second satellite user in the overlapping area of the first satellite are respectively;andthe covariance matrix of the phase errors of the satellite channel of the first satellite user and the interference channel of the second satellite user in the overlapping area of the first satellite are respectively; w1,m=w1,mw1,m HIs a first satellite beam matrix, W2,l=w2,lw2,l HIs a second satellite beam matrix, P1,kAnd P2,kAntenna power limits for a first satellite having K1 antennas and a second satellite having K2 antennas, Z[i,j]Represents the ith row and the jth column element of the matrix Z, and T is more than or equal to 0, and represents that the matrix T is a semi-positive definite matrix; eta1,m,nAnd η2,l,sThe residual interference coefficient, gamma, generated by imperfect decoding caused by successive interference cancellation technique when the first satellite user and the second satellite user decode respectively1,m,nAnd gamma2,l,sMinimum signal to interference plus noise ratio requirements, p, for the first satellite user and the second satellite user, respectively1,m,nAnd p2,l,sThe interruption probability that the first satellite user and the second satellite user can not meet the communication signal-to-interference-and-noise ratio requirement is respectively, a1,m,n,b1,m,nAnd a2,l,s,b2,l,sIs an auxiliary parameter, E1,m,n、Z1,m,n、T1,m,n、A1,m,n、B1,m,n、e1,m,n、e1,l,sAnd E2,m,n、Z2,l,s、T2,l,s、A2,l,s、B2,l,s、e2,m,n、e2,l,sAre all intermediate variables; tr (Z) is a trace of the matrix Z, H in the upper right corner of the variable represents a Hermite transpose, and 2 in the upper right corner of the variable represents a square; f. of1(A) And f2(B) Is two linear transformations, of whichK represents the number of columns of the matrix; δ (m, n) and δ (l, s) take values of 0 or 1, wherein 1 represents that the nth user in the mth beam of the first satellite is interfered by the second satellite or the mth user in the mth beam of the second satellite is interfered by the first satellite, and 0 represents that the user is not interfered; i isK1And IK2Is an identity matrix, with subscript K denoting the dimension;
solving the minimum value of each transmitting power by using an iterative method, wherein the minimum value is Each iteration obtains corresponding W1,mAnd W2,lUp to W1,mAnd W2,lWhen the rank approaches 1, a singular value decomposition method is utilized to obtain a final wave beam w1,mAnd w2,lAnd in each iteration process, an interior point method is adopted or a CVX tool package is directly called to solve.
3. The massive access method based on inter-satellite cooperation according to claim 2, wherein the step 4) is specifically: the total signal transmitted by the first satellite for all users isWherein is alpha1,m,nAllocating a factor, w, to the power in the beam region1,mIs the transmission beam of the m-th region, x1,m,nIs the signal of the nth user in the mth satellite beam area; the total signal transmitted by the second satellite for all users isWherein alpha is2,l,sIs the power allocation factor, w, within the beam region2,lIs a transmission beam in the l region, x2,l,sIs the signal of the s-th user in the area of the l-th satellite beam.
4. The massive access method based on inter-satellite cooperation according to claim 3, wherein the method for serial interference cancellation in step 5) is: any satellite user firstly decodes the signals of users with weaker channel gain than the satellite user in the same area, subtracts the signals from the received signals, and finally decodes the satellite user's signal.
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104320174A (en) * | 2014-09-16 | 2015-01-28 | 南昌航空大学 | Satellite multi-beam collaborative transmission method based on partial channel information |
CN107508659A (en) * | 2017-09-15 | 2017-12-22 | 哈尔滨工程大学 | The adaptive code modulation method passed towards satellite navigation system inter-satellite link number |
CN109995420A (en) * | 2019-01-23 | 2019-07-09 | 长沙天仪空间科技研究院有限公司 | A kind of inter-satellite space communication system and method |
EP3518437A1 (en) * | 2018-01-29 | 2019-07-31 | Ses S.A. | Satellite communications method and system with multi-beam precoding |
CN111464234A (en) * | 2020-06-10 | 2020-07-28 | 网络通信与安全紫金山实验室 | Low-orbit satellite communication performance enhancement method and system based on multi-satellite cooperation |
-
2021
- 2021-03-31 CN CN202110346423.9A patent/CN113194484B/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104320174A (en) * | 2014-09-16 | 2015-01-28 | 南昌航空大学 | Satellite multi-beam collaborative transmission method based on partial channel information |
CN107508659A (en) * | 2017-09-15 | 2017-12-22 | 哈尔滨工程大学 | The adaptive code modulation method passed towards satellite navigation system inter-satellite link number |
EP3518437A1 (en) * | 2018-01-29 | 2019-07-31 | Ses S.A. | Satellite communications method and system with multi-beam precoding |
CN109995420A (en) * | 2019-01-23 | 2019-07-09 | 长沙天仪空间科技研究院有限公司 | A kind of inter-satellite space communication system and method |
CN111464234A (en) * | 2020-06-10 | 2020-07-28 | 网络通信与安全紫金山实验室 | Low-orbit satellite communication performance enhancement method and system based on multi-satellite cooperation |
Non-Patent Citations (2)
Title |
---|
XU XIAOYI: "Design, analysis and optimization of random access inter-satellite ranging system", 《JOURNAL OF SYSTEMS ENGINEERING AND ELECTRONICS》 * |
刘奥: "卫星移动通信***多波束协作传输技术研究", 《中国优秀硕士学位论文全文数据库 信息科技辑》 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114337774A (en) * | 2021-12-13 | 2022-04-12 | 南京邮电大学 | Safe transmission method for double-satellite communication system |
CN114337774B (en) * | 2021-12-13 | 2023-10-10 | 南京邮电大学 | Safe transmission method for double-satellite communication system |
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