Method for power control of FDMA link in MF-TDMA / FDMA hybrid multiple access satellite communication network

Abstract

The application discloses a MF-TDMA / FDMA hybrid multi-address satellite communication network FDMA link power control method, and relates to power control technology in the field of satellite communication. The MF-TDMA general transmission layer is used to gather the FDMA link transceiver end state to the central station, the central station carries out centralized control on the whole network FDMA link power based on the link synchronization time and state aging time algorithm, the purpose of fast synchronization and stable maintenance of the FDMA link is achieved, and the problem of the FDMA link power control in the MF-TDMA / FDMA hybrid multi-address satellite communication network is solved. The application has the characteristics of accurate initial transmission power estimation and differentiated processing of different rate carriers, and is particularly suitable for the MF-TDMA / FDMA hybrid multi-address satellite communication network.

Description

Technical Field

[0001] This invention relates to power control technology in the field of satellite communication, and in particular to a power control method for FDMA links in an MF-TDMA / FDMA hybrid multiple access satellite communication network, applicable to MF-TDMA / FDMA hybrid multiple access satellite communication systems. Background Technology

[0002] The MF-TDMA and FDMA hybrid multiple access satellite communication network uses both multiple access methods simultaneously within a single network. It fully leverages the advantages of MF-TDMA's large network capacity and flexible resource allocation, as well as FDMA's high transmission efficiency. Based on MF-TDMA mesh, star, and hybrid star-network topologies, FDMA point-to-point and point-to-multipoint links can be added as needed, resulting in flexible networking methods.

[0003] Since FDMA demodulators can only guarantee reliable operation when the FDMA link reaches its threshold signal-to-noise ratio (SNR), and the SNR of the FDMA link is mainly determined by the transmitting power of the transmitting station, power control must be implemented in the FDMA link. Traditional FDMA systems often use manual calibration or central station detection feedback to achieve power control. Manual calibration requires manually adjusting the transmitting power at the transmitting end to achieve a higher SNR at the receiving end to combat external environmental changes such as rain attenuation, wasting on-board transponder power resources and lacking flexibility in activation. The central station detection feedback method is for FDMA star networks, where the central station receives all return links. When the central station detects that the SNR of a return link is lower than the SNR threshold, it feeds back to the transmitting end through the forward control channel to adjust its transmitting power. In satellite communication networks with hybrid MF-TDMA and FDMA multiple access, the FDMA multiple access method is not a star topology, and FDMA links can also be established between remote stations. Therefore, the central station detection feedback method is not applicable in this system. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of traditional FDMA power control methods in the aforementioned background art when applied to MF-TDMA / FDMA hybrid multiple access satellite communication networks, and to propose an FDMA link power control method for MF-TDMA / FDMA hybrid multiple access satellite communication networks. This method, based on link synchronization time and state aging time algorithms, centrally controls the power of all FDMA links in the network through a central station, thus solving the FDMA link power control problem in hybrid multiple access satellite communication networks and is applicable to FDMA link power control in MF-TDMA / FDMA hybrid multiple access satellite communication networks.

[0005] The objective of this invention is achieved as follows:

[0006] A method for FDMA link power control in an MF-TDMA / FDMA hybrid multiple access satellite communication network, wherein the satellite communication network includes a network management center, a central station, and multiple remote stations, the central station and remote stations are collectively referred to as earth stations, each earth station is configured with at least one MF-TDMA transmit channel and one MF-TDMA receive channel, and FDMA transmit and receive channels are configured as needed, each earth station in the satellite communication network uses MF-TDMA channels to build a general transmission layer, and FDMA dedicated links are established between earth stations as needed, each FDMA link consisting of one transmitting station and multiple receiving stations; the method includes the following steps:

[0007] (1) Based on theoretical calculations or actual measurements, the upper limit of the synchronization time of the FDMA link at different rates is obtained, and a synchronization schedule is generated and configured in the system as a system parameter.

[0008] (2) Based on the superframe period C sf The maximum number of FDMA transceiver channels N per station determines the FDMA link status reporting timeout T. timeout :

[0009] T timeout =C sf ×N

[0010] T timeout Configured in the system as a system parameter;

[0011] (3) Configure the maximum transmit power and maximum hold time for each FDMA transmit channel in the earth station, and configure the expected signal-to-noise ratio for each FDMA receive channel under each modulation and coding scheme, and configure them as earth station parameters in the earth station.

[0012] (4) Each earth station in the satellite communication network uses the MF-TDMA channel to build a general transmission layer. When an earth station joins the network, it obtains the current time from the network management center and synchronizes it to the local time. The earth stations that join the network maintain time synchronization.

[0013] (5) The network management center configures the FDMA link between earth stations through the general transport layer and sends the link parameters to the sending station and the receiving station. The sending station estimates the initial transmission power of the FDMA link based on the general transport layer reference carrier.

[0014] (6) The transmitting station of the FDMA link periodically reports the transmission status through the general transmission layer back to the network control channel, including the transmitting channel ID, current transmitting power, maximum transmitting power, maximum channel hold time and transmitting channel configuration time. The receiving station of the FDMA link periodically reports the receiving status through the general transmission layer back to the network control channel, including the receiving channel ID, lock status, receiving signal-to-noise ratio, threshold signal-to-noise ratio and receiving channel configuration time.

[0015] (7) The central station receives the FDMA link transmission status and reception status of each earth station, adds a timestamp to each status, identifies an FDMA link with the sending station address and transmission channel ID, and establishes a link status table;

[0016] (8) The central station periodically traverses the link status table, removes aging links and aging nodes in the links, and filters out the trustworthy links.

[0017] (9) The central station detects the status of all receiving stations on the confidence link, adjusts the link status of the confidence link, calculates the power adjustment value for the link that needs to be adjusted, sends power control signaling to the transmitting station, and adjusts the transmitting power of the transmitting station.

[0018] (10) After receiving the power control signaling, the earth station adjusts the transmission power of the FDMA link of the corresponding transmission channel.

[0019] Optionally, in step (5), the transmitting station estimates the initial transmit power of the FDMA link based on the general transport layer reference carrier, specifically as follows:

[0020]

[0021]

[0022] Where P is the initial transmit power of the FDMA link, P e P is the expected transmit power of the FDMA link. r S represents the current transmit power of the TDMA reference carrier. f S is the FDMA link symbol rate. r is the TDMA reference carrier symbol rate; T is the maximum transmit power of the transmit channel.

[0023] Optionally, step (8) specifically includes the following steps:

[0024] (801) Traverse each link in the link state table. If the timestamp of the sent state is more than T away from the current time... timeout If the link is identified as an aging link, it will be removed from the link status table.

[0025] (802) Traverse each receive state of each link in the link state table. If the timestamp of the receive state is more than T away from the current time... timeout If the receiving status is not cleared, the node is considered to be an aging node in the link and is removed from the link.

[0026] (803) Traverse each link in the link status table, determine the upper limit of the link synchronization time according to the synchronization time table and the link rate, and if the transmission and reception channel configuration time of the link is more than the upper limit of the synchronization time, then the link is considered a trustworthy link.

[0027] Optionally, step (9) specifically includes the following steps:

[0028] (901) Divide the state of the link into initial state, adjustment state, stable state and maintenance state, and the state of the newly established link is the initial state;

[0029] (902) Links in the initial state unconditionally jump to the adjustment state;

[0030] (903) If a link is in adjustment state and there is an unlocked receiving station, the transmission power of the link is increased by 3dBm each time, with the upper limit being the maximum transmission power of the transmitting station.

[0031] (904) If a link in the adjustment state has a current signal-to-noise ratio that does not reach the desired signal-to-noise ratio when all receiving stations are locked, the transmission power of the link is increased. The modulation value is the difference between the desired signal-to-noise ratio and the current signal-to-noise ratio, and the upper limit is the maximum transmission power of the transmitting station.

[0032] (905) If a link is in the adjustment state and all receiving stations are locked, and the current signal-to-noise ratio of a receiving station exceeds the expected signal-to-noise ratio and the difference is greater than 4dB, the transmission power of the link is reduced. The adjustment value is the current signal-to-noise ratio minus the expected signal-to-noise ratio plus 2dB.

[0033] (906) If all receiving stations are locked and the signal-to-noise ratio is greater than the expected signal-to-noise ratio and the difference between the expected signal-to-noise ratio and the expected signal-to-noise ratio does not exceed 4dB, the link enters a stable state.

[0034] (907) When a link in a stable state experiences a loss of lock at the receiving station, or when the current signal-to-noise ratio of the receiving station is less than the expected signal-to-noise ratio or the current signal-to-noise ratio exceeds the expected signal-to-noise ratio by 4dB, the link enters a hold state and no power adjustment is performed.

[0035] (908) When a link in the hold state has been in the hold state for longer than the maximum hold time of the transmission channel, it enters the adjustment state.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1. This invention uses a method where the transceiver station periodically reports the FDMA link status to support power control of mesh / star topology FDMA links;

[0038] 2. This invention uses a link synchronization time algorithm to perform fine-grained control over different rates, effectively shortening the link establishment time of high-speed carriers. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of status reporting and power adjustment in an embodiment of the present invention.

[0040] Figure 2 This is a link state transition diagram in an embodiment of the present invention.

[0041] Figure 3 This is a power control flowchart in an embodiment of the present invention. Detailed Implementation

[0042] A power control method for FDMA links in an MF-TDMA / FDMA hybrid multiple access satellite communication network is disclosed. The satellite communication network includes a network management center, a central station, and multiple remote stations. The central station and remote stations are collectively referred to as earth stations. Each earth station is configured with at least one MF-TDMA transmit channel and one MF-TDMA receive channel, and FDMA transmit and receive channels are configured as needed. The satellite communication network uses MF-TDMA channels to build a general transmission layer. Dedicated FDMA links are established between earth stations as needed. Each FDMA link consists of one transmitting station and multiple receiving stations.

[0043] The method includes the following steps:

[0044] (1) Based on theoretical calculations or actual measurements, the upper limit of the synchronization time of the FDMA link at different rates is obtained, and a synchronization schedule is generated and configured in the system as a system parameter.

[0045] (2) Based on the superframe period C sf The maximum number of FDMA transceiver channels N per station determines the FDMA link status reporting timeout T. timeout :

[0046] T timeout =C sf ×N

[0047] T timeout Configured in the system as a system parameter;

[0048] (3) Each FDMA transmit channel in the earth station is configured with its maximum transmit power and maximum hold time, and each FDMA receive channel is configured with the expected signal-to-noise ratio under each modulation and coding scheme. These are configured as earth station parameters in the earth station.

[0049] (4) Each earth station in the network uses the MF-TDMA channel to build a general transmission layer. When an earth station joins the network, it obtains the current time from the network management center and synchronizes it locally. The earth stations that join the network maintain time synchronization.

[0050] (5) The network management center configures the FDMA link between earth stations through the general transport layer and sends the link parameters to the sending station and the receiving station. The sending station estimates the initial transmission power of the FDMA link based on the general transport layer reference carrier.

[0051] (6) The transmitting station of the FDMA link periodically reports the transmission status through the general transmission layer back to the network control channel, including the transmitting channel ID, current transmitting power, maximum transmitting power, maximum channel hold time and transmitting channel configuration time. The receiving station of the FDMA link periodically reports the receiving status through the general transmission layer back to the network control channel, including the receiving channel ID, lock status, receiving signal-to-noise ratio, threshold signal-to-noise ratio and receiving channel configuration time.

[0052] Status reporting diagram as follows Figure 1 As shown;

[0053] (7) The central station receives the FDMA link transmission status and reception status of each earth station, adds a timestamp to each status, identifies an FDMA link with the sending station address and transmission channel ID, and establishes a link status table;

[0054] (8) The central station periodically traverses the link status table, removes aging links and aging nodes in the links, and filters out the trustworthy links.

[0055] (9) The central station detects the status of all receiving stations on the confidence link, adjusts the link status of the confidence link, calculates the power adjustment value for the link that needs to be adjusted, sends power control signaling to the transmitting station, and adjusts the transmitting power of the transmitting station.

[0056] Link state transition diagram as follows Figure 2 As shown, the power control process is as follows: Figure 3 As shown;

[0057] (10) After receiving the power control signaling, the earth station adjusts the transmission power of the FDMA link of the corresponding transmission channel.

[0058] Furthermore, the specific method of step (5) is as follows:

[0059]

[0060]

[0061] Where P is the initial transmit power of the FDMA link, P e P is the expected transmit power of the FDMA link. r S represents the current transmit power of the TDMA reference carrier. f S is the FDMA link symbol rate. r T is the TDMA reference carrier symbol rate; T is the maximum transmit power of the transmit channel;

[0062] Furthermore, the specific method of step (8) is as follows:

[0063] (801) Traverse each link in the link state table. If the timestamp of the sent state is more than T away from the current time... timeoutThe link is identified as an aging link and removed from the link status table.

[0064] (802) Traverse each receive state of each link in the link state table. If the timestamp of the receive state is more than T away from the current time... timeout If the receiving state is identified as an aging node in the link, it will be removed from the link.

[0065] (803) Traverse each link in the link status table, determine the upper limit of the synchronization time of the link according to the synchronization schedule and the link rate, and if the transmission and reception channel configuration time of the link is more than the upper limit of the synchronization time from the current time, the link is identified as a trusted link.

[0066] Furthermore, the specific method of step (9) is as follows:

[0067] (901) Divide the state of the link into initial state, adjustment state, stable state and maintenance state, and the state of the newly established link is the initial state;

[0068] (902) Links in the initial state unconditionally jump to the adjustment state;

[0069] (903) If a link is in the adjustment state and a receiving station is not locked, increase the transmission power of the link by 3dBm each time, with the upper limit being the maximum transmission power of the transmitting station.

[0070] (904) If a link in the adjustment state has a current signal-to-noise ratio that does not reach the desired signal-to-noise ratio when all receiving stations are locked, the transmission power of the link is increased. The modulation value is the difference between the desired signal-to-noise ratio and the current signal-to-noise ratio, and the upper limit is the maximum transmission power of the transmitting station.

[0071] (905) If a link is in the adjustment state and all receiving stations are locked, and the current signal-to-noise ratio of a receiving station exceeds the expected signal-to-noise ratio and the difference is greater than 4dB, the transmission power of the link is reduced. The adjustment value is the current signal-to-noise ratio minus the expected signal-to-noise ratio plus 2dB.

[0072] (906) If all receiving stations are locked and the signal-to-noise ratio is greater than the expected signal-to-noise ratio and the difference between the expected signal-to-noise ratio and the expected signal-to-noise ratio does not exceed 4dB, the link enters a stable state.

[0073] (907) When a link in a stable state experiences a loss of lock at the receiving station, or when the current signal-to-noise ratio of the receiving station is less than the expected signal-to-noise ratio or the current signal-to-noise ratio exceeds the expected signal-to-noise ratio by 4dB, the link enters a hold state and no power adjustment is performed.

[0074] (908) When a link in the hold state has been in the hold state for longer than the maximum hold time of the transmission channel, it enters the adjustment state.

[0075] Steps (903) to (906) are repeated to continuously adjust the link status and the transmitting power of the transmitting station.

[0076] In summary, this invention uses an MF-TDMA universal transport layer to aggregate the states of FDMA link transceivers to a central station. The central station centrally controls the power of all FDMA links in the network based on link synchronization time and state aging time algorithms, achieving rapid and stable FDMA link synchronization and solving the FDMA link power control problem in MF-TDMA / FDMA hybrid multiple access satellite communication networks. This invention features accurate initial transmit power estimation and differentiated processing for carriers of different rates, making it particularly suitable for MF-TDMA / FDMA hybrid multiple access satellite communication networks.

Claims

1. A method for controlling the power of an FDMA link in an MF-TDMA / FDMA hybrid multiple access satellite communication network, characterized in that, The satellite communication network includes a network management center, a central station, and multiple remote stations. The central station and remote stations are collectively referred to as earth stations. Each earth station is configured with at least one MF-TDMA transmit channel and one MF-TDMA receive channel, and FDMA transmit / receive channels are configured as needed. Earth stations within the satellite communication network use MF-TDMA channels to form a general transmission layer. Dedicated FDMA links are established between earth stations as needed. Each FDMA link consists of one transmitting station and multiple receiving stations. The network includes the following steps: (1) Based on theoretical calculations or actual measurements, the upper limit of the synchronization time of the FDMA link at different rates is obtained, and a synchronization schedule is generated and configured in the system as a system parameter. (2) Based on the superframe period C sf The maximum number of FDMA transceiver channels N per station determines the FDMA link status reporting timeout T. timeout : T timeout =C sf ×N T timeout Configured in the system as a system parameter; (3) Configure the maximum transmit power and maximum hold time for each FDMA transmit channel in the earth station, and configure the expected signal-to-noise ratio for each FDMA receive channel under each modulation and coding scheme, and configure them as earth station parameters in the earth station. (4) Each earth station in the satellite communication network uses the MF-TDMA channel to build a general transmission layer. When an earth station joins the network, it obtains the current time from the network management center and synchronizes it to the local time. The earth stations that join the network maintain time synchronization. (5) The network management center configures the FDMA link between earth stations through the general transport layer and sends the link parameters to the sending station and the receiving station. The sending station estimates the initial transmission power of the FDMA link based on the general transport layer reference carrier. (6) The transmitting station of the FDMA link periodically reports the transmission status through the general transmission layer back to the network control channel, including the transmitting channel ID, current transmitting power, maximum transmitting power, maximum channel hold time and transmitting channel configuration time. The receiving station of the FDMA link periodically reports the receiving status through the general transmission layer back to the network control channel, including the receiving channel ID, lock status, receiving signal-to-noise ratio, threshold signal-to-noise ratio and receiving channel configuration time. (7) The central station receives the FDMA link transmission status and reception status of each earth station, adds a timestamp to each status, identifies an FDMA link with the sending station address and transmission channel ID, and establishes a link status table; (8) The central station periodically traverses the link status table, removes aging links and aging nodes in the links, and filters out the trustworthy links. (9) The central station detects the status of all receiving stations on the confidence link, adjusts the link status of the confidence link, calculates the power adjustment value for the link that needs to be adjusted, sends power control signaling to the transmitting station, and adjusts the transmitting power of the transmitting station. (10) After receiving the power control signaling, the earth station adjusts the transmission power of the FDMA link of the corresponding transmission channel.

2. The FDMA link power control method in an MF-TDMA / FDMA hybrid multiple access satellite communication network according to claim 1, characterized in that, In step (5), the transmitting station estimates the initial transmit power of the FDMA link based on the general transport layer reference carrier, specifically as follows: Where P is the initial transmit power of the FDMA link, P e P is the expected transmit power of the FDMA link. r S represents the current transmit power of the TDMA reference carrier. f S is the FDMA link symbol rate. r is the TDMA reference carrier symbol rate; T is the maximum transmit power of the transmit channel.

3. The FDMA link power control method in an MF-TDMA / FDMA hybrid multiple access satellite communication network according to claim 1, characterized in that, Step (8) specifically includes the following steps: (801) Traverse each link in the link state table. If the timestamp of the sent state is more than T away from the current time... timeout If the link is identified as an aging link, it will be removed from the link status table. (802) Traverse each receive state of each link in the link state table. If the timestamp of the receive state is more than T away from the current time... timeout If the receiving status is not cleared, the node is considered to be an aging node in the link and is removed from the link. (803) Traverse each link in the link status table, determine the upper limit of the link synchronization time according to the synchronization time table and the link rate, and if the transmission and reception channel configuration time of the link is more than the upper limit of the synchronization time, then the link is considered a trustworthy link.

4. The FDMA link power control method in an MF-TDMA / FDMA hybrid multiple access satellite communication network according to claim 1, characterized in that, Step (9) specifically includes the following steps: (901) Divide the state of the link into initial state, adjustment state, stable state and maintenance state, and the state of the newly established link is the initial state; (902) Links in the initial state unconditionally jump to the adjustment state; (903) If a link is in adjustment state and there is an unlocked receiving station, the transmission power of the link is increased by 3dBm each time, with the upper limit being the maximum transmission power of the transmitting station. (904) If a link in the adjustment state has a current signal-to-noise ratio that does not reach the desired signal-to-noise ratio when all receiving stations are locked, the transmission power of the link is increased. The modulation value is the difference between the desired signal-to-noise ratio and the current signal-to-noise ratio, and the upper limit is the maximum transmission power of the transmitting station. (905) If a link is in the adjustment state and all receiving stations are locked, and the current signal-to-noise ratio of a receiving station exceeds the expected signal-to-noise ratio and the difference is greater than 4dB, the transmission power of the link is reduced. The adjustment value is the current signal-to-noise ratio minus the expected signal-to-noise ratio plus 2dB. (906) If all receiving stations are locked and the signal-to-noise ratio is greater than the expected signal-to-noise ratio and the difference between the expected signal-to-noise ratio and the expected signal-to-noise ratio does not exceed 4dB, the link enters a stable state. (907) When a link in a stable state experiences a loss of lock at the receiving station, or when the current signal-to-noise ratio of the receiving station is less than the expected signal-to-noise ratio or the current signal-to-noise ratio exceeds the expected signal-to-noise ratio by 4dB, the link enters a hold state and no power adjustment is performed. (908) When a link in the hold state has been in the hold state for longer than the maximum hold time of the transmission channel, it enters the adjustment state.

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