A satellite call access control method

[0040] The satellite network of the future needs to support multiple services and provide different QOS guarantees for different services. Therefore, a differentiated service method is commonly used in satellite networks to divide different services into several priority levels, and different priority levels have different QOS guarantees. In access control, services of different priorities also need to be treated differently. Satellites give priority to meeting high-priority resource requirements and prioritize access to high-priority services. For the sake of simplicity, in the following description, services are mainly divided into two types: high-priority services and low-priority services. For simplification, it is assumed that the QOS requirements of high-priority services include the minimum number of resources and the number of expected resources; the QOS requirements of low-priority services include the minimum number of resources and the number of expected resources, and the former can be zero.

[0041] Symbol Description:

[0042] W unused : Remaining resources of the system (can be wireless channels, transmit power, etc.);

[0043] W 1_min : The minimum number of resources required for high-priority services;

[0044] W 1_req : Expected demand number of high-priority business;

[0045] W 2_req : The number of expected resources for low-priority services;

[0046] net-utility: The net utility of a business call to the allocation of specific resources. Its model is:

[0047]

[0048] Where: U j (r i , T) indicates that service call j is assigned to specific resource r i The generated utility, β(t) is the price factor of the resource per satellite, a 3 , B 3 Is the scale factor, and ρ(t) is the proportion of the total resources on the planet that the system has allocated resources at time t;

[0049] Borrowing weight: determines the order in which the objects in the system borrowing library are borrowed. The model is:

[0050] borrow-weight=(net-utility□t stay ) (1+n) ,

[0051] Where: t stay Represents the stay time of the call in the current cell, and n represents the number of times the call has been borrowed during the entire communication process.

[0052] u1: Threshold for high-priority service access control;

[0053] u2: Threshold for low priority access control;

[0054] The specific implementation steps of the present invention are as follows:

[0055] The access request described in the present invention includes the access request initiated by a new call and the call switching request initiated by the cell switching of the calling terminal in the call due to satellite motion. As shown in Figure 1, first, determine the call type, if If it is a handover call, the handover call request access processing is performed, and if it is a new call, the new call request access processing is performed.

[0056] Judging whether to switch a call or a new call is distinguished by the message flag bit, which is distinguished by the message type in the message in the present invention, as shown in the following figure:

[0057]

[0058] 1. Handover call request access processing, as shown in Figure 2, when handover call j arrives:

[0059] (1) If the call service is a low-priority service (the low-priority service is distinguished by the service type flag in the message payload), the on-board resource manager calculates that it is within the range allowed by the service resource request (0, W 2_req ) The minimum net utility of the business min (The so-called minimum net utility refers to (0, W 2_req ) The smallest net utility value among all possible net utility values ​​within the resource range), if net-utility min ≥u2, proceed to the next judgment; otherwise, reject the access request.

[0060] (a) The system judges whether the remaining resources on the satellite meet the minimum resource requirements for low-priority service access, if not, reject the call; if it is satisfied, proceed to the next step;

[0061] (b) Whether the remaining resources on the satellite meet w unused ≥a·W 2_req (Where a represents the threshold factor for the call to be added to the channel borrowing library, and its value is between [0, 1]. When the satellite resources are sufficient, the system allocates a*W as much as possible 2_req The number of resources, thereby increasing the number of borrowable calls in the resource borrowing library, thereby reducing the blocking rate of high-priority service calls. The parameter a can be adjusted appropriately to meet the QOS requirements of the satellite system. Here, it mainly refers to the new call blocking rate and the handover call drop rate). If it is satisfied, the call request is accessed, and the system allocates a*W to it. 2_req The number of on-board resources, the system will calculate the call’s borrowing weight (calculate the call’s allocation of a*W at the moment 2_req The net utility of the resource, the remaining dwell time in the current beam, and the number of times the call is borrowed during the entire communication process can get the borrowing weight), and add it to the channel borrowing library (the borrowing library is the satellite’s prior It is created and saved in the on-board storage unit. It is empty at first, and then will continue to add or delete the index numbers of low-priority handover calls that can be used as resource borrowing objects. During the joining process, the system will according to the call borrowing weight from small to Store in large order; when borrowing is needed, the system will first take the call with the smallest weight; when the call in the channel borrowing library is switched or the communication ends, it will also be removed from the library; otherwise, proceed to the next step;

[0062] (c) The on-board resource manager calculates within the range allowed by the business resource request (0, min(W unused , W 2_req )) The maximum net utility of the business net-utility max (The so-called maximum net utility refers to (0, min(W unused , W 2_req )) The largest net utility value among all possible net utility values ​​within the resource range), access the call request, and the system allocates net-utility to it max The number of corresponding resources;

[0063] (2) If the handover call service is a high-priority service, the on-board resource manager calculates that it is within the range allowed by the service resource request (W 1_min , W 1_req ) The minimum net utility of the business min (The method is the same as above), if net-utility min ≥u1, proceed to the next judgment; otherwise, reject the access request.

[0064] (a) The system judges whether the remaining resources on the satellite meet the minimum resource requirements for service access (W unused ≥W 1_min ), if not satisfied, go to step (b); if satisfied, go to step (d);

[0065] (b) If the on-board resource borrowing library is empty, if it is empty, reject the access request, otherwise proceed to step (c);

[0066] (c) The system will select the service with the smallest borrowing weight from the channel borrowing library as the resource borrowing object of the new handover call. This object will give up part of the satellite resources it occupies for the access of the handover call. The object is removed from the library; after resource borrowing, if the remaining resources of the system meet the minimum resource requirement of service call j (W 1_min ), the resource borrowing process is completed, and step (d) is entered; if the resource requirement of the call is still not met, step (b) is entered;

[0067] (d) The on-board resource manager calculates within the range allowed by the business resource request (W 1_min , Min(W unused , W 1_req )) The maximum net utility of the business net-utility max (The method is the same as above), access the call and assign net-utility to it max The number of corresponding resources.

[0068] 2. New call request access processing, as shown in Figure 3, when a new call j arrives:

[0069] (1) If the new call service is a low-priority service, the on-board resource manager calculates that it is within the range allowed by the service resource request (0, W 2_req ) The minimum net utility of the business min (The method is the same as above), if net-utility min ≥u2, proceed to the next judgment; otherwise, reject the access request.

[0070] (a) The system judges whether the remaining resources on the satellite meet the minimum resource requirements for service access (W unused0), if not satisfied, reject the new call; if satisfied, proceed to the next judgment;

[0071] (b) Whether the remaining resources on the satellite meet W unused ≥a·W 2_req , If it is satisfied, access the call request, and the system will allocate a*W to it 2_req For the number of on-board resources, the system will calculate the borrowing weight of the call and add it to the channel borrowing library; otherwise, proceed to the next step of judgment;

[0072] (c) The on-board resource manager calculates within the range allowed by the business resource request (0, min(W unused , W 2_req )) The maximum net utility of the business net-utility max (The calculation method is the same as above), the system accesses the call request and allocates net-utility to it max The number of corresponding resources;

[0073] (2) If the call service is a high-priority service, the on-board resource manager calculates within the range allowed by the service resource request (W 1_min , W 1_req ) The minimum net utility of the business min(The method is the same as above), if net-utility min ≥u1, proceed to the next judgment; otherwise, reject the access request.

[0074] (a) The system judges whether the remaining resources on the satellite meet the minimum resource requirements for service access (W unused ≥W 1_min ), if it is not satisfied, reject the new call; if it is satisfied, proceed to the next step; (b) the on-board resource manager calculates the service within the scope allowed by the service resource request (W 1_min , Min(W unused , W 1_req ) Maximum net utility net-utility max , Access to the new call request, the system allocates net-utility to it max The number of corresponding resources;

[0075] The satellite network needs a long period of testing time before it starts to work, and some key parameters of the system need to be configured to achieve the purpose of the satellite network's stable operation. The thresholds u1 and u2 are very important system parameters, and the system adjusts the system load condition through it. The selection of the threshold can be obtained through computer simulation in advance, that is, the threshold can be obtained under the conditions of a given system QOS requirements, load conditions and working environment. Because the threshold value is restricted by many factors, it is difficult to express it with a model, and it needs continuous testing to get it.