Wireless communication node autonomous collaborative networking method for lunar surface activity

Abstract

The invention discloses a wireless communication node autonomous cooperative networking method for lunar surface activity, which belongs to the field of spaceflight communication, constructs a lunar surface communication network overall architecture composed of an access network and a backbone network, comprehensively uses a TDM main and auxiliary node communication mode, TDD and TDMA uplink and downlink communication modes, and an OFDM physical layer transmission waveform, and provides a wireless communication node autonomous cooperative networking method for lunar surface activity. A lunar surface communication network communication system is formed, and cooperative networking and self-adaptive expansion of the lunar surface communication network are completed through mutual cooperation of five physical layer channel types; under the constraint of an air interface index, a modulation coding mode is autonomously allocated to each user node, so that the time slot proportion of each link is determined, the time slot resource of each user node is coordinated, and the modulation coding mode and the time slot proportion are dynamically adjusted in real time according to the channel estimation state of the current user node. According to the invention, the problem of lunar multi-node wireless networking is innovatively solved, and the balance between lunar limited resources and multi-node flexible allocation is realized.

Description

Technical Field

[0001] The present invention relates to the field of space communication, and in particular to a method for autonomous collaborative networking of wireless communication nodes for lunar surface activities. Background Art

[0002] During the manned lunar exploration process, in order to facilitate the exploration activities, it is necessary to build a communication system adapted to the lunar surface conditions, so that nodes such as spacecraft, astronauts, lunar rovers, scientific payloads, and robots can be interconnected through wireless mobile communication methods. The construction of the lunar surface communication system needs to overall consider the requirements of realistic engineering tasks and the long-term planning of future lunar scientific research and development stages, explore the construction of lunar scientific research test stations, carry out continuous lunar exploration and related technical test verification of the system, and gradually realize in-situ resource utilization on the lunar surface and lunar resource development. This goal of sustainability and compatibility puts extremely high requirements on the autonomy, flexibility, and scalability of the lunar surface communication system.

[0003] The lunar surface communication network has similarities with the terrestrial mobile communication network in the basic wireless communication technology for supporting mobile nodes. The lunar surface communication network can draw on the technical architecture of the terrestrial mobile communication network to a certain extent. However, lunar surface activities have characteristics such as high-speed transmission requirements for user nodes, limited energy, limited weight, tight frequency resources, and uneven node communication capabilities. Therefore, the lunar surface communication network cannot directly copy the terrestrial mobile communication network.

[0004] At present, the communication methods adopted in the deep space exploration projects implemented at home and abroad are all point-to-point communications for a certain task or a collection of multiple point-to-point communications, which do not meet the requirements of autonomous, flexible, and scalable networking communications required by the manned lunar exploration mission. The engineering implementation is relatively lagging as a whole, and there is no ready-made standard to follow for the project implementation. Therefore, there is an urgent need to invent a method for autonomous collaborative networking of wireless communication nodes that can be applied in actual engineering and adapt to the conditions of lunar surface activities. Summary of the Invention

[0005] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, providing a method for autonomous collaborative networking of wireless communication nodes for lunar surface activities, meeting the need for interconnection and communication of various nodes in lunar exploration activities, and being able to meet the needs of current engineering tasks and adapt to the long-term planning of future scientific research and development stages.

[0006] The technical solution of the present invention is: A method for autonomous collaborative networking of wireless communication nodes for lunar surface activities, including:

[0007] Constructing the overall architecture of the lunar surface communication network, including an access network and a backbone network. A unique master node and several expandable slave nodes are allocated in the backbone network. The access network is formed by networking one or more user nodes; a master node and each slave node are respectively provided with an access network;

[0008] The analysis clearly includes the master - slave node communication mode, the uplink and downlink communication modes, the physical layer transmission waveform, and the physical layer channel type, forming the communication system of the lunar communication network.

[0009] Obtain the air - interface metrics for user node access; under the constraint of air - interface metrics, autonomously allocate modulation and coding modes for each user node.

[0010] Based on the corresponding modulation and coding modes, determine the time - slot ratio of each link, coordinate the time - slot resources of each user node; according to the channel estimation status of the current user node, dynamically adjust the modulation and coding modes and the time - slot ratio in real - time.

[0011] Furthermore, in the lunar communication network, user nodes within the same access network form a network for communication with their affiliated master node or slave node, and the master nodes and slave nodes of the backbone network form a network for communication with each other.

[0012] Furthermore, the master - slave node communication mode, the uplink and downlink communication modes, and the physical layer transmission waveform in the communication system of the lunar communication network are specifically as follows:

[0013] According to the backbone network communication cycle, within each communication cycle, a number of minimum time - slot units are divided at fixed intervals. Each minimum time - slot unit is used for broadcasting or by one user node; the physical layer wireless transmission waveform of each user node consists of A OFDM sub - carriers in frequency, and the interval between each sub - carrier is B kHz, and A×B kHz does not exceed the total available frequency bandwidth; the master node is responsible for the time - period management of the entire network, forming time - division multiplexing between the master and slave nodes. The master node and the slave node respectively manage their own communication cycles, allocate time - slots for the uplink and downlink and user nodes, forming time - division duplexing and time - division multiple access. At the same time, different communication antennas are allocated according to the antenna positions registered when the user nodes access, forming space - time - division multiple access.

[0014] Furthermore, taking 80 ms as a backbone network communication cycle, within each communication cycle, 80 minimum time - slot units are divided at intervals of 1 ms, and the interval between each sub - carrier is 15 kHz.

[0015] Furthermore, the physical layer channel type and composition are specifically as follows:

[0016] The five physical layer channel types, namely the downlink broadcast channel PBCH, the uplink random access channel PRACH, the downlink control channel PDCCH, the uplink shared channel PUSCH, and the downlink shared channel PDSCH, cooperate with each other to complete the collaborative networking and adaptive expansion of the lunar communication network. Among them, PBCH is used for the primary and secondary nodes to send broadcasts to user nodes and carry key system information; PRACH is used for user nodes to send initial access preambles to the primary and secondary nodes based on the key system information carried by PBCH to complete the initial network access application; PDCCH is used for the primary and secondary nodes to transmit the signaling and control information required for initial network access to user nodes; PDSCH is used for the primary and secondary nodes to transmit downlink data, downlink control information, and signaling to user nodes; PUSCH is used for user nodes to transmit uplink data, uplink control information, and signaling response messages to the primary and secondary nodes.

[0017] Furthermore, the autonomous allocation of modulation and coding modes for each user node includes:

[0018] According to the applicable frequency band range of the communication nodes, allocate frequency resources for each link and determine the communication bandwidth;

[0019] According to the communication distance range between communication nodes, calculate the space loss of each link; according to the transmit power and antenna gain of the communication nodes, combined with the space loss, considering the cable insertion loss and link design margin, calculate the received signal-to-noise ratio of each link; based on the communication bandwidth and the received signal-to-noise ratio, calculate the link peak information rate R bi ', where i takes values of 1, 2, 3... 2n, and n is the total number of user nodes in the lunar communication network;

[0020] Thus, according to the calculated link peak information rate R bi ', allocate the modulation and coding mode for each user node;

[0021] Each modulation and coding mode includes the corresponding modulation method, modulation order, LDPC code rate, number of RBs, and communication rate. Compare the link peak information rate R bi ' with the communication rate, and use the modulation and coding mode corresponding to the communication rate that exceeds and is closest to it as the modulation and coding mode of the user node.

[0022] Furthermore, the UHF communication frequency bands of 390 MHz - 405 MHz, 410 MHz - 420 MHz, and 435 MHz - 450 MHz are adopted between communication nodes, and there are three available total bandwidth modes: 15 MHz, 25 MHz, and 40 MHz.

[0023] Furthermore, based on the corresponding modulation and coding mode, determining the time slot ratio of each link and coordinating the allocation of time slot resources for each user node includes:

[0024] Establish an initial superframe;

[0025] Normalize the available time slot resources after removing the overhead, including uplink and downlink time slot resources;

[0026] Based on the modulation and coding mode, determine the time slot ratio of each link, and combine with the peak information rate of the link to obtain the actual information rate after the uplink and downlink time slot allocation of each user node;

[0027] According to the size of the uplink and downlink data volume of the user node and the actual information rate after the uplink and downlink time slot allocation of each link, dynamically divide the uplink and downlink time slots of the data, determine the proportion of the uplink and downlink time slots, and perform uplink and downlink time slot allocation; after the uplink and downlink time slot allocation of all user nodes in the whole network is successful, a complete superframe is formed on the basis of the initial superframe, and the length of the superframe is one backbone network communication cycle.

[0028] Furthermore, the real-time dynamic adjustment of the modulation and coding mode and the time slot ratio includes:

[0029] According to the channel estimation state of the user node, judge in real time whether the user node can further increase the peak information rate R bi ' of the link to meet k i ·R bi ' exceeds and is closest to R bi as a condition, dynamically adjust the modulation and coding mode and the time slot ratio of each link, and optimize the allocation of network resources; where k i is the time slot ratio of link i, R bi ' is the peak information rate of link i, R bi is the actual information rate after the time slot allocation of link i, and i takes 1, 2, 3... 2n, where n is the total number of user nodes in the lunar communication network.

[0030] Furthermore, preset the modulation and coding modes under different frequency resources and different modulation methods for selection when allocating or adjusting the modulation and coding mode. The preset modulation and coding modes are shown in the following table:

[0031] MCS Modulation Method Modulation Order LDPC Code Rate Number of RBs Communication Rate (Mbps) 1 BPSK 1 100 / 1024 8 0.08 2 QPSK 2 193 / 1024 8 0.32 3 QPSK 2 308 / 1024 8 0.528 4 QPSK 2 308 / 1024 16 1.032 5 QPSK 2 526 / 1024 16 1.8 6 QPSK 2 526 / 1024 32 3.624 7 16QAM 4 378 / 1024 32 5.12 8 QPSK 2 526 / 1024 64 7.04 9 16QAM 4 378 / 1024 64 10.248 10 QPSK 2 526 / 1024 128 14.088 11 16QAM 4 378 / 1024 128 20.496 12 16QAM 4 658 / 1024 128 35.856 13 16QAM 4 873 / 1024 128 47.112 14 16QAM 4 873 / 1024 192 71.688 15 QPSK 2 193 / 1024 4 0.16 。

[0032] The advantages of the present invention compared with the prior art are as follows:

[0033] (1) Propose a flexible and adaptive collaborative networking overall architecture. The overall architecture of lunar surface wireless communication with access network + backbone network proposed by the present invention innovatively solves the problem of lunar surface multi-node wireless networking, realizes the balance between limited lunar surface resources and flexible allocation of multi-nodes, has high adaptability, can not only flexibly adapt to the needs of small-scale scenarios of initial lunar exploration missions, but also has strong scalability, supports the expansion of the networking scale, can cover the scale requirements within a certain time span during the construction stage, and has the ability to support the continuous evolution process, which is conducive to realizing the support for more different participants in future lunar surface activities.

[0034] (2) Improve the utilization efficiency and self-usage ability of physical layer resources. The frequency resources on the lunar surface are scarce. With the increase of lunar surface activity nodes, it is necessary to seek higher-efficiency bandwidth utilization technologies. The present design of the invention comprehensively applies communication technology elements such as TDD, TDMA, and OFDM to realize lunar surface wireless communication, and solves the problems of lunar surface network capacity and transmission efficiency from aspects such as spectrum resource utilization and multi-user access according to user capabilities and channel environment estimation, which conforms to the inevitable trend of the development of lunar surface wireless communication networks.

[0035] (3) Realize the collaborative networking communication of lunar surface multi-nodes. Compared with the simple point-to-point communication method of traditional lunar surface activities, this solution can establish a wireless lunar surface communication network for information networking exchange. By establishing a specific information exchange mechanism between the master node and users, multi-node collaborative networking is realized, and communication resources are reasonably allocated to multiple users, which can meet the current and future lunar surface wireless networking communication needs for a certain period. With the increase of the lunar surface activity detection task volume, it can also be applied to subsequent different lunar surface activity tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the flowchart of the method of the present invention;

[0037] Figure 2 It is the schematic diagram of the lunar surface communication network architecture of the present invention;

[0038] Figure 3 It is the schematic diagram of the communication system of the lunar surface communication network of the present invention;

[0039] Figure 4 It is the schematic diagram of the physical layer channel composition of the lunar surface communication network of the present invention;

[0040] Figure 5 It is the schematic diagram of the UHF communication frequency band of the lunar surface communication network of the present invention;

[0041] Figure 6 It is the schematic diagram of the superframe structure of the lunar surface communication network of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0042] To better understand the technical solution of the present invention, the following specifically elaborates on the specific implementation manners of the present invention in conjunction with the accompanying drawings.

[0043] Here, the nouns in the present invention are first uniformly described: the lunar surface communication network is the general term for the backbone network and the access network; the communication node represents any node in the lunar surface communication network, that is, it may be the main node, the secondary node, or the user node; the main node and the secondary node are the communication nodes in the backbone network and are also called the central hubs; the user node is the final communication node in the access network and is also called the terminal. The link sent by the user node and received by the main / secondary node is the uplink, and the link sent by the main / secondary node and received by the user node is the downlink.

[0044] The wireless communication node autonomous collaborative networking method for lunar surface activities proposed by the present invention, as Figure 1 shown, includes the following steps:

[0045] Step 1: Construct the overall architecture of the lunar surface communication network.

[0046] In order to not only meet the needs of collaborative networking communication under the constraints of weight, power consumption, environment, etc. in the current engineering tasks, but also adapt to the long-term flexible scalability requirements in the future scientific research and development stages, according to the requirements of lunar surface activities for the lunar surface wireless communication network, the overall architecture of the lunar surface communication network is designed as a two-layer architecture of access network + backbone network. The access network realizes short-distance (0m - 1km) user collaborative networking, and the backbone network realizes medium- and long-distance (1km - 5km) extended networking.

[0047] The overall architecture is as Figure 2 shown. A unique main node and several expandable secondary nodes are allocated in the backbone network. The main node and each secondary node respectively subordinate an access network, and the access network is formed by networking multiple user nodes. The main node serves as the management central hub of the whole network, responsible for the management of communication resources and users of the whole network. The secondary node cooperates with the main node to manage the access network composed of its subordinate user nodes.

[0048] The user nodes within the same access network communicate with the main node or secondary node to which they belong through networking. The main node and the secondary node in the backbone network communicate with each other through networking. After the user node is powered on, it receives the broadcast signal of its own main / secondary node, and then sends an access request to the main / secondary node. The main / secondary node authenticates the user node and allocates resources, and the user node completes access according to the allocated resources. Different user nodes accessed under the same main / secondary node form an access network and conduct networking communication through direct connection to the access network; user nodes accessed under different main / secondary nodes conduct networking communication through the access network + backbone network.

[0049] When the main node drops offline or leaves, according to the preset priority, a secondary node is selected to be upgraded to a new main node.

[0050] Step 2: Form the communication regime of the lunar communication network.

[0051] Analyze and clarify the communication elements including the communication mode between the primary and secondary nodes, the uplink and downlink communication modes, the physical layer transmission waveform, and the composition of the physical layer channels.

[0052] In this solution, the physical layer is designed to use the OFDM wireless transmission waveform. The TDM time division multiplexing mode is adopted between the primary and secondary nodes. TDD time division duplexing and TDMA time division multiple access are used between the uplink and downlink. The user nodes adopt the STDMA space-time division multiple access method.

[0053] Specifically, as Figure 3 shown, the lunar communication network takes 80 ms as a backbone network communication cycle. Within each communication cycle, 80 smallest time slot units are divided at intervals of 1 ms. Each smallest time slot unit is used for broadcasting or a certain user node. The physical layer wireless transmission waveform of each user node consists of A OFDM subcarriers in frequency. The interval between each subcarrier is 15 kHz, and A×15 kHz does not exceed the total available frequency bandwidth. The primary node is responsible for the time cycle management of the entire network and forms the time division multiplexing (TDM) between the primary and secondary nodes. The primary / secondary nodes respectively manage their own 80 ms cycles, allocate time slots for the uplink / downlink and different users, form time division duplexing (TDD) and time division multiple access (TDMA), and at the same time allocate different communication antennas according to the antenna positions registered during user access to form space-time division multiple access (STDMA).

[0054] For the physical layer channel types and compositions, as Figure 4 shown, 5 physical layer channel types are set: downlink broadcast channel (PBCH), uplink random access channel (PRACH), downlink control channel (PDCCH), uplink shared channel (PUSCH), downlink shared channel (PDSCH). The 5 channels cooperate with each other to complete the collaborative networking and adaptive expansion of the lunar communication network. Among them, PBCH is used for the primary / secondary nodes to send broadcasts to the user nodes, and this channel carries key system information in the most reliable signal manner; based on the key system information carried by PBCH, the user nodes use PRACH to send initial access preambles to the primary / secondary nodes to complete the initial network access application; PDCCH mainly transmits the signaling and control information required for initial network access from the primary / secondary nodes to the user nodes; PDSCH mainly transmits downlink data from the primary / secondary nodes to the user nodes, as well as some system messages, downlink control information, and signaling; PUSCH mainly transmits uplink data from the user nodes to the primary / secondary nodes, and can also transmit uplink control information, signaling response messages, channel measurement information, etc.

[0055] Step 3: Obtain the air interface metrics for user node access.

[0056] The air interface metrics mainly include the communication conditions available for each communication node to access, such as the communication distance range, applicable frequency band range, transmit power under device weight and energy constraints, antenna gain, etc.; the communication channel estimation capabilities of each communication node; and also include the addresses that each user node can be authorized for access application, authorization, and communication management.

[0057] Step 4: Independently allocate modulation and coding modes for each user node under the constraints of air interface metrics.

[0058] Step 4.1: According to the applicable frequency band ranges of each communication node determined in the previous step, allocate frequency resources for each link and determine the communication bandwidth B.

[0059] Specifically, Figure 5 , referring to the requirements of the International Telecommunication Union (ITU), select the lunar UHF communication frequency bands as 390 MHz - 405 MHz, 410 MHz - 420 MHz, and 435 MHz - 450 MHz. There are three total bandwidth modes available for use: 15 MHz, 25 MHz, and 40 MHz.

[0060] Step 4.2: According to the communication range determined in Step 3, use the communication link model to calculate the space loss of each link;

[0061] Specifically, the space loss calculation process is as follows:

[0062]

[0063] where R is the distance between two communication nodes and λ is the communication wavelength;

[0064] Step 4.3: According to the transmit power and antenna gain of each node determined in Step 3, combined with the space loss calculated in Step 4.2, considering cable insertion loss, link design margin, etc., calculate the received signal-to-noise ratio of each link;

[0065] Specifically, the calculation process of the received signal-to-noise ratio S / N0 is as follows:

[0066]

[0067] In the formula, ∑L i is the sum of various losses including pointing loss and polarization loss, S F is the system design margin, and EIRP is the equivalent isotropic radiated power:

[0068] EIRP (dBm) = P T (dBm) + G T (dBm) - L tc (dB)

[0069] In the formula, P T is the transmit power, GT is the transmitting antenna gain, L tc is the radio frequency cable feed loss between the transmitter and the transmitting antenna port.

[0070] Step 4.4: Calculate the peak information rate of each link;

[0071] Specifically, the peak information rate R b ' of the link can be calculated by the following formula:

[0072]

[0073] In the formula, the symbol signal-to-noise ratio E b / N0 that meets the bit error rate requirement is restricted by the selected modulation method (BPSK, QPSK, 16QAM, etc.). After obtaining the communication bandwidth B and the receiver received signal-to-noise ratio S / N0 through Steps 4.1 to 4.3, the peak information rate R b ' of the link can be calculated. The peak information rate of each link is denoted as R bi ', where i takes 1, 2, 3... 2n, and n is the total number of user nodes in the lunar communication network.

[0074] In a possible implementation, typical modulation and coding modes under different frequency resources and different modulation methods are preset in the system, as shown in Table 1, where each RB is 12 subcarriers and the bandwidth of each subcarrier is 15 kHz. According to the calculated R bi ', select the communication rate in Table 1 that exceeds and is closest to R bi ' as the modulation and coding mode (MCS) of the user node, and determine the corresponding modulation method, modulation order, LDPC code rate, and the number of RBs.

[0075] Table 1 Modulation and coding modes in this embodiment

[0076]

[0077] Step 5: Based on the corresponding modulation and coding mode, determine the time slot ratio of each link and coordinate the time slot resources of each user node; according to the channel estimation status of the current user node, dynamically adjust the modulation and coding mode and the time slot ratio in real time.

[0078] Step 5.1: Establish an initial superframe according to the common information. Only the physical broadcast channel (PBCH) and the physical downlink control channel (PDCCH) are allocated in the initial superframe.

[0079] Step 5.2: After removing the overhead such as the cyclic prefix and the control information of the initial superframe, normalize the available time slot resources to 1, which includes the time slot resources of the user uplink and downlink.

[0080] Step 5.3: Based on the node communication capabilities and rate requirements, obtain the actual information rates after the uplink and downlink time slot allocations for each user node.

[0081] Specifically, the actual information rate R of each link after time slot allocation bi The calculation process is as follows:

[0082] R b1 = k1·R b1 ', R b2 = k2·R b2 ',......, R b2n = k 2n ·R b2n '

[0083] s.t. k1 + k2 +... + k 2n = 1

[0084] In the formula, there are a total of 2n links for all n users in the lunar communication network, and k i is the proportion of the time slot allocated to the i-th link in the total time resource.

[0085] Specifically, in time slot allocation, the time slot ratio k of the link i is determined according to the modulation and coding scheme (MCS). The principle for selecting k i is that for a link with relatively weak communication capabilities but high rate requirements, the coefficient k should be appropriately increased i to increase the time slot division; for a link with relatively strong communication capabilities and general rate requirements, the coefficient k should be appropriately decreased i . The sign of successful time slot allocation is that all R b1 ~R b2n meet the communication rate requirements of the users.

[0086] Step 5.4: Define the ratio of uplink and downlink data volumes and divide the uplink and downlink time slots;

[0087] Specifically, the master / slave node dynamically divides the uplink and downlink time slots of the data according to the magnitudes of the uplink and downlink data volumes of the user nodes and the actual information rates of each uplink and downlink link after time slot allocation, and determines the proportions of the uplink and downlink time slots;

[0088] After the uplink and downlink time slot allocations for all user nodes in the entire network are successful, a complete superframe is formed based on the initial superframe. The schematic diagram of the superframe is as shown in Figure 6 and the length of the superframe is 80 ms.

[0089] Step 5.5: The master / slave node makes flexible and dynamic adjustments to the MSC and k according to the channel estimation states of the nodes that have joined the network (the channel estimation states are obtained based on the channel estimation capabilities of each node in Step 3) i, so as to adapt to the change of the communication requirements of the user node.

[0090] Specifically, the user node puts forward the communication requirement R to the master / slave node bi , that is, the actual information rate that the information source can send after the time slot allocation. The master / slave node judges the available R of the current link according to the channel estimation state bi ', and determines k according to the available blank time slots in the superframe i ·R bi ' can meet the R put forward by the user bi requirement, and allocate necessary communication time slots for the user. When k i ·R bi ' exceeds and is closest to R bi at that time, it is considered that the allocation is successful.

[0091] Specifically, to keep the system running in the optimal state, the master / slave node always judges whether the user has the condition to further improve the peak information rate R bi ' of the link according to the channel estimation states submitted by itself and the user, and finds the maximum available R bi ' and the minimum time slot ratio k i in accordance with the communication rate grades in Table 1, so that k i ·R bi ' exceeds but is closest to R bi , and dynamically updates through signaling control, so as to dynamically adjust the modulation and coding mode, improve the peak information rate, reduce its time resource requirements, and optimize the allocation of communication network resources.

[0092] There may be different sectors in the backbone node. When the terminal uses the corresponding functional channels, it operates in its corresponding sector. The shared channels are allocated on demand and point to the corresponding sectors according to the service requirements.

[0093] Step 5.6, after a new user accesses, the master node allocates shared channel resources to the newly accessed user according to the current whole-network resource status, that is, the shared uplink channel and the shared downlink channel, for user communication data transmission and user management information or signaling transmission, and updates the superframe allocation for all network nodes.

[0094] It can be understood that the present invention is described by way of examples. Those skilled in the art know that, without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and examples. In addition, under the teaching of the present invention, these features and examples can be modified to adapt to specific situations without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and the embodiments that can fall within the scope of the claims of this application all belong to the scope protected by the present invention.

[0095] The content not detailed in the description of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A method for autonomous collaborative networking of wireless communication nodes for lunar surface activities, characterized in that, Including: Construct the overall architecture of the lunar communication network, including the access network and the backbone network. In the backbone network, a unique main node and several scalable secondary nodes are allocated. The access network is formed by networking one or more user nodes. A access network is set under the main node and each secondary node respectively; Analyze and clarify that it consists of the communication mode between the main and secondary nodes, the uplink and downlink communication modes, the physical layer transmission waveform, and the physical layer channel type, to form the communication regime of the lunar communication network; Obtain the air interface metrics for user node access; Autonomously allocate modulation and coding modes for each user node under the constraint of the air interface metrics; Based on the corresponding modulation and coding modes, determine the time slot ratio of each link, and coordinate the time slot resources of each user node. According to the channel estimation status of the current user node, dynamically adjust the modulation and coding modes and the time slot ratio in real time.

2. The method for autonomous collaborative networking of wireless communication nodes for lunar surface activities according to claim 1, characterized in that: In the lunar communication network, the user nodes within the same access network communicate with the main node or secondary node to which they belong, and the main node and secondary nodes of the backbone network communicate with each other.

3. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to claim 1, characterized in that: The communication modes between the main and secondary nodes, the uplink and downlink communication modes, and the physical layer transmission waveform in the communication regime of the lunar communication network are specifically as follows: According to the communication cycle of the backbone network, within each communication cycle, a number of minimum time slot units are divided at fixed intervals. Each minimum time slot unit is used for broadcasting or a user node. The physical layer wireless transmission waveform of each user node consists of A OFDM subcarriers in frequency, and the interval between each subcarrier is B kHz, and A×B kHz does not exceed the total available frequency bandwidth. The main node is responsible for the time cycle management of the entire network, forming time division multiplexing between the main and secondary nodes. The main node and secondary nodes respectively manage their own communication cycles, allocate time slots for the uplink and downlink and user nodes, forming time division duplexing and time division multiple access. At the same time, different communication antennas are allocated according to the antenna positions registered when the user nodes access, forming space-division time-division multiple access.

4. The method for autonomous collaborative networking of wireless communication nodes for lunar surface activities according to claim 3, wherein: Taking 80ms as a backbone network communication cycle, within each communication cycle, 80 minimum time slot units are divided at 1ms intervals, and the interval between each subcarrier is 15kHz.

5. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to claim 3, wherein: The physical layer channel type and composition are specifically as follows: Downlink broadcast channel PBCH, uplink random access channel PRACH, downlink control channel PDCCH, uplink shared channel PUSCH, downlink shared channel PDSCH. These 5 physical layer channel types cooperate with each other to complete the collaborative networking and adaptive expansion of the lunar communication network. Among them, PBCH is used for the main and secondary nodes to send broadcasts to user nodes, carrying key system information; PRACH is used for user nodes to send initial access preambles to the main and secondary nodes based on the key system information carried by PBCH to complete the initial network access application; PDCCH is used for the main and secondary nodes to transmit the signaling and control information required for initial network access to user nodes; PDSCH is used for the main and secondary nodes to transmit downlink data, downlink control information and signaling to user nodes; PUSCH is used for user nodes to transmit uplink data, uplink control information and signaling response messages to the main and secondary nodes.

6. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to claim 1, wherein: The autonomous allocation of modulation and coding modes for each user node includes: Allocate frequency resources for each link according to the applicable frequency band range of the communication node, and determine the communication bandwidth; Calculate the space loss of each link according to the communication distance range between communication nodes; calculate the received signal-to-noise ratio of each link based on the transmit power and antenna gain of the communication node, combined with the space loss, considering the cable insertion loss and link design margin; calculate the link peak information rate R based on the communication bandwidth and received signal-to-noise ratio bi ', where i takes values of 1, 2, 3... 2n, and n is the total number of user nodes in the lunar communication network; Thus, according to the calculated link peak information rate R bi ', a modulation and coding mode is allocated to each user node; Each modulation and coding mode includes a corresponding modulation method, modulation order, LDPC code rate, number of RBs, and communication rate. Compare the peak information rate R of the link bi 'with the communication rate, and use the modulation and coding mode corresponding to the communication rate that exceeds and is closest to it as the modulation and coding mode of the user node.

7. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to claim 6, wherein: The UHF communication frequency bands of 390 MHz to 405 MHz, 410 MHz to 420 MHz, and 435 MHz to 450 MHz are adopted between communication nodes, and there are 3 modes that can utilize the total bandwidth: 15 MHz, 25 MHz, and 40 MHz.

8. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to claim 1, wherein: Based on the corresponding modulation and coding mode, determine the time slot ratio of each link and coordinately allocate the time slot resources of each user node, including: Establish an initial superframe; Normalize the available time slot resources after excluding the overhead, including the uplink and downlink time slot resources; Based on the modulation and coding mode, determine the time slot ratio of each link, and combine the peak information rate of the link to obtain the actual information rate of the uplink and downlink of each user node after time slot allocation; According to the size of the uplink and downlink data volume of the user node and the actual information rate after the uplink and downlink time slot allocation of each link, dynamically divide the uplink and downlink time slots of the data, determine the proportion of the uplink and downlink time slots, and perform uplink and downlink time slot allocation; after the uplink and downlink time slot allocation of all user nodes in the whole network is successful, a complete superframe is formed on the basis of the initial superframe, and the superframe length is a backbone network communication cycle.

9. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to claim 8, characterized in that: The real-time dynamic adjustment of the modulation and coding mode and the time slot ratio includes: According to the channel estimation state of the user node, it is determined in real time whether the user node can further increase the link peak information rate R bi ', to satisfy k i ·R bi ' exceeds and is closest to R bi As a condition, dynamically adjust the modulation and coding mode and the time slot ratio of each link, and optimize the allocation of network-wide resources; where k i is the time slot ratio of link i, R bi ' is the link peak information rate of link i, R bi is the actual information rate after time slot allocation of link i, i takes values 1, 2, 3... 2n, and n is the total number of user nodes in the lunar communication network.

10. The method for autonomous cooperative networking of wireless communication nodes for lunar surface activities according to any one of claims 6 to 9, characterized in that: Preset the modulation and coding modes under different frequency resources and different modulation methods for selection when allocating or adjusting the modulation and coding mode. The preset modulation and coding modes are shown in the following table: 。

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