Communication bandwidth allocation method for non-ground network

Abstract

The invention discloses a communication bandwidth allocation method for a non-ground network, which relates to the technical field of wireless communication, and comprises the following steps of: determining propagation delay tau i of each user equipment in a satellite coverage area, and calculating longest propagation delay tau M and shortest propagation delay tau m; defining a protection interval Tth as Tth = 2 (tauM-taum) + tUL; wherein tUL is the duration of uplink transmission; in the protection interval, a plurality of time slots of the same type are distributed, including uplink time slots or downlink time slots, and the time slots do not interfere with other concurrent transmission; according to the signal-to-noise ratio or the propagation delay, a user equipment subset is selected for transmission so as to maximize the ergodic capacity of each state, and the condition for distributing the additional downlink time slot is that when the interval time after the previous downlink time slot is finished is Tth, the additional downlink time slot is arranged, and 2 [tau] m is greater than or equal to tUL. According to the communication bandwidth allocation method for the non-ground network, two scheduling strategies are combined, and the ergodic capacity of each state can be maximized or the transmission delay difference can be reduced according to actual requirements.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a communication bandwidth allocation method for a non-terrestrial network. Background Art

[0002] With the development of 6G communication technology, the integration of terrestrial and non-terrestrial networks has become a trend. Non-terrestrial networks can provide communication services to remote areas with their wide coverage capabilities. However, the propagation delay problem in non-terrestrial networks is significant, especially in time-division duplex mode. The overhead of synchronization and protection intervals is large, resulting in low resource utilization.

[0003] In existing technologies, the timing advance mechanism is used to address the propagation delay problem. However, the length of its guard interval is proportional to the cell size and propagation delay, which results in significant resource waste in satellite networks. Currently, there is no efficient method to allocate additional time slots during the guard interval to reduce overhead. Summary of the Invention

[0004] The object of the present invention is to provide a communication bandwidth allocation method for non-terrestrial networks to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a communication bandwidth allocation method for a non-terrestrial network, comprising the following steps:

[0006] Determine the propagation delay τ of each user device within the satellite coverage area i , and calculate the longest propagation delay τ M and the shortest propagation delay τ m ;

[0007] Define the protection interval T th for:

[0008] T th =2(τ M -τ m )+t UL ;

[0009] where t UL is the duration of uplink transmission;

[0010] During the guard interval, multiple time slots of the same type are allocated, including uplink time slots or downlink time slots, and the time slots do not interfere with other concurrent transmissions;

[0011] Based on the signal-to-noise ratio or propagation delay, a subset of user devices is selected for transmission to maximize the ergodic capacity.

[0012] Furthermore, the conditions for allocating additional downlink time slots are:

[0013] The interval time after the end of the previous downlink time slot is T th When , additional downlink time slots are arranged and 2τ is satisfied m ≥t UL .

[0014] Furthermore, the following scheduling strategy is adopted: select N s The user equipment with the highest signal-to-noise ratio.

[0015] Furthermore, the goals are: |S|=N s ;

[0016] Furthermore, the following scheduling strategy is adopted: select N s with minimum propagation delay.

[0017] Furthermore, the goals are: in |S|=N s ;

[0018] Furthermore, non-terrestrial networks include low-Earth orbit satellite networks or high-altitude platform networks.

[0019] Furthermore, the propagation delay τ i Calculated by the following formula: i =d i / c, where d i is the distance between the user equipment and the satellite, and c is the speed of light.

[0020] Furthermore, the distance d i Determined by the following formula:

[0021]

[0022] where R E is the radius of the Earth, α i is the upward angle from the device to the satellite, and h is the satellite altitude.

[0023] The present invention provides a communication bandwidth allocation method for non-terrestrial networks, which has the following beneficial effects: by allocating additional time slots during the protection interval, the present invention significantly reduces resource waste and improves network efficiency; by combining two scheduling strategies, the ergodic capacity of each state can be maximized or the transmission delay difference can be reduced according to actual needs; and the present invention is applicable to various non-terrestrial network scenarios, including LEO satellites and HAP networks, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a scenario of a communication bandwidth allocation method for a non-terrestrial network according to the present invention;

[0025] Figure 2 A schematic diagram of misaligned time slot interference in a communication bandwidth allocation method for a non-terrestrial network according to the present invention;

[0026] Figure 3 A schematic diagram of a communication bandwidth allocation method for non-terrestrial networks with a timing advance according to the present invention;

[0027] Figure 4 A schematic diagram of a communication bandwidth allocation method for non-terrestrial networks according to the present invention. DETAILED DESCRIPTION

[0028] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0029] like Figure 1 As shown, a communication bandwidth allocation method for a non-terrestrial network includes the following steps:

[0030] Determine the propagation delay τ of each user device within the satellite coverage area i , and calculate the longest propagation delay τ M and the shortest propagation delay τ m ;

[0031] Define the protection interval T th for:

[0032] T th =2(τ M -τ m )+t UL ;

[0033] where t UL is the duration of uplink transmission;

[0034] During the guard interval, multiple time slots of the same type are allocated, including uplink time slots or downlink time slots, and the time slots do not interfere with other concurrent transmissions;

[0035] Based on the signal-to-noise ratio or propagation delay, a subset of user devices is selected for transmission to maximize the ergodic capacity.

[0036] The conditions for allocating additional downlink time slots are:

[0037] The interval time after the end of the previous downlink time slot is T th When , additional downlink time slots are arranged and 2τ is satisfied m ≥t UL .

[0038] Use the following scheduling strategy: select Ns The user equipment with the highest signal-to-noise ratio.

[0039] The goals are: |S|=N s ;

[0040] Use the following scheduling strategy: select N s with minimum propagation delay.

[0041] The goals are: in |S|=N s ;

[0042] Non-terrestrial networks include low-Earth orbit satellite networks or high-altitude platform networks.

[0043] Propagation delay τ i Calculated by the following formula: i =d i / c, where d i is the distance between the user equipment and the satellite, and c is the speed of light.

[0044] Distance d i Determined by the following formula:

[0045]

[0046] where R E is the radius of the Earth, α i is the upward angle from the device to the satellite, and h is the satellite altitude.

[0047] Specifically, it consists of N user devices, which are connected to a LEO satellite at an altitude h via a direct link. Only one satellite is considered, which can provide the function of a next-generation node base station. The system is in a stable state, and the propagation delays of uplink (UL) and downlink (DL) transmissions are fixed. At the frame-level transmission time level, the movement of the satellite and the movement of the device are considered negligible.

[0048] For the channel, the main channel path loss between device i and satellite is:

[0049] PL i =FPL i +A g +A s +SF

[0050] Where FPL is the free space path loss (FSPL), A g It is the loss caused by the atmosphere, A sIt is the scintillation loss caused by the sudden change of refractive index due to changes in temperature, water vapor content and air pressure.

[0051] SF represents the shadow fading component, which is modeled as having a mean of zero and a variance of σ s A normally distributed random variable, σ s The value of depends on many factors, including channel conditions, scenario, and elevation angle;

[0052] The formula for FSPL is: i =92.45+20log(f)+20log(d i )f is the carrier frequency, d i It's distance.

[0053] like Figure 2 As shown, two devices are connected to the same satellite. The satellite transmits a downlink time slot, which is received by device 1 after time T1 and by device 2 after time T2. If uplink time slots are assigned to the two user devices immediately after the corresponding downlink time slots, the uplink time slots at the satellite cannot be synchronized due to the different propagation delays of the two user devices. This misalignment will lead to uncoordinated transmissions causing interference.

[0054] Using the Time Advance (TA) mechanism, it is assumed that each user device knows its own position and the satellite position and can estimate the propagation delay of the uplink channel. The user device can report this estimate to the satellite, and the satellite calculates the longest propagation delay in the cell based on it, which is recorded as τ M , which corresponds to the farthest user equipment in the satellite coverage area. This information is used to perform TA and maintain transmission synchronization, such as Figure 3 As shown;

[0055] In this setup, the guard interval between downlink and uplink time slots must be equal to 2τ M ,The overhead depends on the longest link in the network, and a ,too long guard interval will lead to inefficient use of radio ,resources in satellite networks.

[0056] Specifically, assuming there is an additional downlink time slot ( Figure 4 The downlink of the satellite line 2) in the first downlink time slot ( Figure 4 The downlink of the satellite is scheduled after 1) passing through, and will be sent to user equipment i at T th +τ i is received, assuming that the uplink time slot associated with the first downlink time slot ( Figure 4 The upper row 1) is used by device i at t0+τ i +2(τ M -τ i ) is sent at the same time, and the duration is t UL, that extra download slot will not be disturbed as long as:

[0057] 2(τ M -τ m )+t UL +τ i ≥τ i +2(τ M -τ i )+t UL

[0058] This is true, as long as τ m ≤τ i , and this i must exist, as long as

[0059] like Figure 4 As shown, for the entire system, "Downlink 2" arranges another uplink time slot ("Uplink 1") after 2. If there are available time slots after the time interval after the end of "Downlink 2" is equal to , other downlink time slots can be arranged. For example, "Downlink 3" is arranged immediately after receiving "Uplink 1". This scheduling process is repeated until all data packets are arranged.

[0060] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A communication bandwidth allocation method for non-terrestrial networks, characterized in that: The following steps are involved: Determine the propagation delay τ of each user device within the satellite coverage area i , and calculate the longest propagation delay τ M and the shortest propagation delay τ m ; Define the protection interval T th for: T th =2(τ M -t m )+t UL ; where t UL is the duration of uplink transmission; During the guard interval, multiple time slots of the same type are allocated, including uplink time slots or downlink time slots, and the time slots do not interfere with other concurrent transmissions; Based on the signal-to-noise ratio or propagation delay, a subset of user devices is selected for transmission to maximize the ergodic capacity.

2. A communication bandwidth allocation method for non-terrestrial networks according to claim 1, characterized in that: The conditions for allocating additional downlink time slots are: The interval time after the end of the previous downlink time slot is T th When , additional downlink time slots are arranged and 2τ is satisfied m ≥t UL .

3. A communication bandwidth allocation method for non-terrestrial networks according to claim 1, characterized in that: Use the following scheduling strategy: select N s The user equipment with the highest signal-to-noise ratio.

4. A communication bandwidth allocation method for non-terrestrial networks according to claim 3, characterized in that: The goals are:

5. The communication bandwidth allocation method for non-terrestrial networks according to claim 1, characterized in that: Use the following scheduling strategy: select N s with minimum propagation delay.

6. A communication bandwidth allocation method for non-terrestrial networks according to claim 5, characterized in that: The goals are: in 7. A communication bandwidth allocation method for non-terrestrial networks according to claim 6, characterized in that: Non-terrestrial networks include low-Earth orbit satellite networks or high-altitude platform networks.

8. A communication bandwidth allocation method for non-terrestrial networks according to claim 7, characterized in that: Propagation delay τ i Calculated by the following formula: i =d i / c, where d i is the distance between the user equipment and the satellite, and c is the speed of light.

9. A communication bandwidth allocation method for non-terrestrial networks according to claim 8, characterized in that: Distance d i Determined by the following formula: where R E is the radius of the Earth, α i is the upward angle from the device to the satellite, and h is the satellite altitude.

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