CN102098685B - Spectrum reuse communication system and method based on GSM network - Google Patents

Abstract

The invention discloses a global system for mobile communication (GSM) network-based spectrum reuse communication system. The system mainly overcomes the irrationality of spectrum use in the current GSM network. The implementation mode comprises the following steps of: (1) in the existing GSM network, adding a function entity defined by the standard IEEE1900.4, comprising adding an operator spectrum manager (OSM) and a network reconstruction manager (NRM) in a network sub-system (NSS), adding a radio access network reconstruction controller (RRC) and a radio access network measurement collector (RMC) in a base sub-system (BSS) and adding a terminal reconstruction manager (TRM), a terminal reconstruction controller (TRC) and a terminal measurement collector (TMC) in a mobile terminal system (MS); (2) arranging a new interface connected with the original network on the added entity and arranging a message structure transmitted on the interface; (3) on the basis of the system, planning a specific communication process of an unauthorized user so that the unauthorized user passes message through each interface to assist the unauthorized user in finishing the use of idle frequency range in the GSM network. By utilizing the GSM network-based spectrum reuse communication system, the utilization rate of the network spectrum can be improved. The invention further discloses a GSM network-based spectrum reuse communication method.

Description

Spectrum reuse communication system and method based on GSM network

technical field

The invention belongs to the technical field of wireless communication, and relates to a tiled reuse system based on the GSM network, which is used for the access of non-local registered users to improve spectrum utilization.

Background technique

my country's radio technology has always used the static spectrum allocation method. Communication can only work on the dedicated frequency band assigned to it, that is, the entire spectrum is divided into several frequency bands and allocated to different departments or operators, and the frequency band can only be used by The authorized users belonging to the group can use it, and other unauthorized users cannot access or use the frequency band. In fact, it has been proved by the monitoring of various agencies at home and abroad that there are no or few authorized users to use these fixedly allocated frequency bands for a considerable period of time. band. Among these fixedly allocated frequency bands, only some frequency bands are frequently used. This situation constitutes a waste of use of spectrum resources to a certain extent. At present, my country is in the transitional period from the second generation communication to the third generation or even the fourth generation communication. The rapid development of the communication industry, the overlapping coverage of various communication networks, and the rapid increase of various radio users make the wireless spectrum resources very scarce. Among them, the second-generation wireless communication GSM is a relatively mature communication network that has been developed for a long time in my country. But the GSM cellular communication network is also facing the shortage of spectrum resources. As mentioned above, many valuable spectrum resources are not used by authorized users within a certain period of time and are often idle. However, because these spectrums have been allocated, many unlicensed users cannot use these spectrums when they are urgently waiting for communication. This unreasonable use makes the already scarce spectrum resources more and more tense. Obviously, this utilization method is in conflict with the current shortage of non-renewable spectrum resources, and the shortage of wireless resources is the bottleneck that restricts the sustainable development of wireless communication and services. Therefore, technologies for reusing non-renewable spectrum resources have received widespread attention.

In order to improve spectrum utilization and solve the problem of ineffective use of such scarce resources, the existing methods mainly include two aspects: one is to adopt more advanced technology on the basis of the existing communication network, or to make appropriate modifications ; on the other hand is the study of new shared spectrum networks. Cognitive radio technology is a new functional spectrum sharing technology. It was proposed in 1999. It effectively improves the spectrum utilization rate in view of the uneven use of wireless frequency bands. It can rely on the support of artificial intelligence to perceive time domain, In the wireless communication environment such as frequency domain and space, according to its own decision-making and algorithm, it can judge, detect and effectively use idle spectrum in real time, and theoretically allow spectrum multiplexing in time domain, frequency domain and space. This technology is considered to be the most promising wireless technology, however, new spectrum sharing technologies are usually limited to short-distance communication with transmission power, which limits the capacity and flexibility of the communication system. Moreover, the current theory of cognitive technology focuses on the construction of a new cognitive network. Although this solution can solve the problem of spectrum resource shortage to a certain extent, in practical applications, this requires a major modification of the existing communication network. In terms of hardware or software, the cost of loss is huge, and the operability is limited to a certain extent.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, and propose a spectrum reuse communication system and communication method based on the GSM network, based on the premise of minimal changes to the existing network, to meet the requirements of unlicensed users for the allocated spectrum in idle conditions Reasonable use, reduce loss overhead, and improve spectrum utilization.

To achieve the above object, the system of the present invention includes mobile terminal MS, base station subsystem BSS and network subsystem NSS, characterized in that:

Add functional entities defined by the IEEE1900.4 standard in the mobile terminal MS, which includes terminal measurement collector TMC, terminal reconfiguration manager TRM, and terminal reconfiguration controller TRC. These functional entities communicate with the base station through the air interface Um in the GSM network Subsystem BSS transmits messages;

The functional entity defined by the IEEE1900.4 standard is added to the base station subsystem BSS, which includes the radio access network measurement collector RMC and the radio access network reconfiguration controller RRC, and the radio access network measurement collector RMC is connected with the physical entity The radio access network reconfiguration controller RRC is integrated, the radio access network reconfiguration controller RRC is provided with a new Acon interface, and the radio access network reconfiguration controller RRC is connected to the base station controller BSC in the GSM network through the Acon interface;

Add the functional entities defined by the IEEE1900.4 standard in the network subsystem NSS, which includes the operator spectrum manager OSM and the network reconfiguration manager NRM. The operator spectrum manager OSM is integrated with the network reconfiguration manager NRM in physical entities , the network reconfiguration manager NRM is provided with a new H interface, and the network reconfiguration manager NRM is connected to the mobile switching center MSC in the original GSM network through the H interface.

In order to achieve the above object, the communication method of the present invention has not only retained the communication of the authorized user in the GSM network, but also added the communication of the non-authorized user;

Said unauthorized user communications, including:

(1) Unauthorized user access and traffic channel TCH allocation process:

1a) In the absence of communication requirements, an unauthorized user monitors the spectrum usage of the cell on a designated broadcast channel;

1b) When an unlicensed user generates a spectrum demand, he or she sends a channel application to the network, and transmits a service request on the channel allocated to it. The unlicensed user has not registered in the network, and the subsequent authentication process fails;

1c) The user who fails to authenticate applies to the network reconfiguration manager NRM through a cognitive request message, and the network reconfiguration manager NRM judges whether to allow the user to access according to an internal algorithm. If rejected, the call process ends; if allowed, the network The reconfiguration manager NRM returns a cognitive confirmation message, and the mobile switching center MSC orders the visitor location register VLR to assign a temporary identity to the unauthorized user through a temporary identity request message, and the temporary identity is registered in the network by the mobile switching center MSC through a temporary number registration message. Register in the reconstruction manager NRM;

1d) Unauthorized users reapply for the second channel with a temporary identity. The second access process is the same as that of authorized users and the TCH allocation process of traffic channels. After the TCH allocation of traffic channels is completed, the system notifies the wireless access network to re-apply. The structural controller RRC marks the channels used by unauthorized users;

1e) During the call, if an authorized user applies for access to the frequency band being used by an unlicensed user, the unlicensed user will effectively avoid it, and at the same time the network reconfiguration manager NRM periodically monitors the channel. In the case of conflict or high channel occupancy, alarm or forcibly interrupt communication services for unauthorized users accessing;

(2) Disconnecting process of unauthorized users:

2a) The mobile station MS sends a disconnection message, and the disconnection message is transmitted to the mobile switching center MSC;

2b) After the mobile switching center MSC receives the message, there will be two actions, one is to issue a release command to the base station manager BSC, and the other is to send a forward disconnection command to the mobile switching center MSC where the called party is located. TUP message request;

2c) The release command is issued by the mobile switching center MSC to the mobile station MS, and the mobile station MS deactivates all the channels occupied by this call. After receiving the confirmation message from the mobile station MS, the mobile switching center MSC sends a message to the network reconfiguration manager NRM issues a request to clear the registration of the cognitive station;

2d) After the visitor location register VLR receives the release command from the network reconfiguration manager NRM, it clears out the temporary number assigned to the unauthorized user and the supporting authentication three parameters;

2e) After the clearing is successful, the network reconfiguration manager NRM cancels the registration of the cognitive user, the base station subsystem BSS releases the wireless resources, and marks all the ground resources allocated to this call as idle;

2f) Cancel the channel registration of the unauthorized user in the radio access network reconfiguration controller RRC, the mobile switching center MSC releases the terrestrial resources, and the disconnection process ends.

The present invention has the following advantages:

(1) The present invention adds some functional entities in the GSM cellular network structure to manage the communication of unlicensed users and the monitoring and judgment of authorized frequency bands. Access and use of GSM network spectrum through newly defined messages under the condition of affecting authorized user communication.

(2) Since the present invention modifies the upper-layer communication protocol and formulates a communication process suitable for unauthorized users to access the network, the unauthorized users can access and use the frequency band of the local network when the frequency band of the local network is idle, and the frequency band of the local network can be obtained More fully utilized, effectively improving the spectrum utilization.

(3) Since the present invention adds a new functional entity to the existing GSM network structure, the network coverage involved is the same as the original network, the communication distance is flexible and unrestricted, and the complexity of building a new cognitive network is avoided. In practical applications, this method is easier to implement and more operable.

Description of drawings

Fig. 1 is a block diagram of existing GSM system entity structure;

Fig. 2 is a block diagram of the entity structure of the GSM system of the present invention;

Fig. 3 is that the present invention formulates the spectrum reuse communication flow chart based on GSM network;

Fig. 4 is a format diagram of a cognitive request message in the present invention;

Fig. 5 is a format diagram of a cognitive reception message in the present invention;

Fig. 6 is a format diagram of a temporary number registration message in the present invention;

Fig. 7 is a format diagram of a temporary identity request message in the present invention;

Fig. 8 is the sub-district coverage figure that simulation of the present invention adopts;

Fig. 9 is a simulation diagram of the use of each channel by total users under the condition that unauthorized users and authorized users jointly access the network in the present invention;

Fig. 10 is a simulation diagram of the use of each channel by an authorized user in the absence of an unauthorized user in the present invention;

Detailed ways

Referring to the above-mentioned accompanying drawings, the specific implementation manners of the present invention will be described in further detail.

Referring to Fig. 1, it is a block diagram of the physical structure of the existing GSM system. The existing GSM network system is mainly composed of a mobile station MS, a base station subsystem BSS, a network subsystem NSS, and an operation and maintenance subsystem OSS: the mobile station MS represents a mobile terminal and its The corresponding customer identification card; the base station subsystem BSS is controlled by the mobile switching center MSC in the network subsystem in a certain wireless coverage area, and communicates with the MS through the air interface Um. The functional entities contained in it can be divided into The base station controller BSC and the base transceiver station BTS; the network subsystem NSS mainly completes the switching function and the database function required for customer data and mobility management and security management. It includes functional entities such as mobile switching center MSC and visitor location register VLR, home location register HLR, authentication center AUC, and equipment identification register EIR; the operation and maintenance subsystem OMC mainly manages and monitors the entire GSM network. One side of it is connected with the network subsystem NSS, and the other side is used as Human interface computer workstation.

Referring to Fig. 2, the present invention is based on the frequency spectrum reuse communication system of GSM network, respectively adds new functional entity in the network subsystem NSS, the base station subsystem BSS and the mobile station in the existing GSM network, wherein:

1. Newly added functional entities in the GSM network subsystem NSS include: Operator Spectrum Manager OSM and Network Reconfiguration Manager NRM. The network reconfiguration manager NRM is provided with an H interface, and this entity is connected with the mobile switching center MSC in the original network through this interface, and it is used for managing the optimal spectrum allocation of the network and terminals; the operator spectrum manager OSM, which is connected with the network The reconfiguration manager NRM is connected to control the dynamic spectrum allocation policy of the network reconfiguration manager NRM, because it only transmits the network selection strategy to the network reconfiguration manager NRM once when the system is initialized, so it is related to the network reconfiguration manager NRM It can be designed as one in physical entities.

The H interface set on the network reconfiguration manager NRM, which is defined as the internal interface between the mobile switching center MSC and the network reconfiguration manager NRM in the network subsystem, is used for the mobile service switching center MSC to network reconfiguration manager NRM Make a cognitive application, transmit the channel usage status of each cell and the registration of unauthorized users.

2. The newly added functional entities in the GSM base station subsystem BSS include: the radio access network reconfiguration controller RRC and the radio access network measurement collector RMC. The radio access network reconfiguration controller RRC is provided with an Acon interface, through which this entity is connected with the base station manager BSC in the base station subsystem, and it is used to implement network reconfiguration for each radio access network according to the requirements of the network reconfiguration manager NRM Access to the network for reconfiguration; the radio access network measurement collector RMC, which is connected to the radio access network reconfiguration controller RRC, is used to collect the background information of the radio access network and pass it to the network reconfiguration manager NRM , in practice, it can be integrated with the RRC design on a physical entity.

The Acon interface set on the radio access network reconfiguration controller RRC is defined in the base station subsystem, the interface between the base station controller BSC and the radio access network reconfiguration controller RRC, on the physical entity, it can be If the two are connected through an interface, the design of the base station controller BSC and the radio access network reconfiguration controller RRC can also be integrated, depending on the specific conditions of each base station subsystem BSS. This interface is mainly used for registration and management of spectrum usage allocation after unauthorized users access the network. In order to avoid the complexity of the structure, there is no direct interface between the network reconfiguration manager NRM and the radio access network reconfiguration controller RRC, and the message transmission between them is through the H interface, the Acon interface and the A interface in the original GSM network. Done together.

3. The newly added functional entities in the mobile terminal MS include: a terminal measurement collector TMC, a terminal reconfiguration manager TRM and a terminal reconfiguration controller TRC. The terminal measurement collector TMC is used to collect the background information of the terminal and transmit it to the terminal reconfiguration manager TRM; the terminal reconfiguration manager TRM is used to manage the terminal part used for spectrum distributed optimization. The management under the policy framework given by the reconstruction manager NRM should refer to the parameters given by the user and the background information provided to it at all levels; the terminal reconstruction controller TRC is used to The request controls the refactoring of the terminal. The message intercommunication between the terminal reconfiguration manager TRM, the network reconfiguration manager NRM and the radio access network reconfiguration controller RRC still needs to be transmitted through the A interface, Abis interface and air Um interface in the original GSM network.

In the present invention, by adding the functional entity defined by the IEEE 1900.4 standard in the original GSM network, the communication system with spectrum reuse function is formed, which not only retains the communication of authorized users in the GSM network, but also adds the communication of non-authorized users;

With reference to Fig. 3, utilize above-mentioned system, the communication process of the present invention to unauthorized user is as follows:

Process 1, when an unauthorized user sends a call, the mobile station MS sends a random pulse on the random access channel RACH to send a dedicated channel SDCCH request message to the base station subsystem BSS, after the base station controller BSC successfully allocates it, the mobile station MS sends a request message on the access allowed channel The mobile station MS is notified through an immediate assignment message in the AGCH.

Process 2, the mobile station MS will send a layer 3 message --- CM service request message on the dedicated channel SDCCH allocated for it, the message is transparently transmitted to the mobile switching center MSC by the base station subsystem BSS, and then the mobile switching center MSC By processing the access request message, the VLR is notified to process the access service request of the mobile station MS. At the same time, the mobile switching center MSC will also send a connection confirmation message to the base station controller BSC to establish a connection between the base station controller BSC and the mobile switching center MSC. There are connection services between SCCP.

Process 3, after receiving the service access request, the visitor location register VLR performs authentication:

First, check whether the mobile station MS has three authentication parameters in the database. If yes, it will directly issue an authentication command to the mobile switching center MSC, otherwise, request to the corresponding home location register and authentication center HLR/AUC Authentication parameters;

Then, issue an authentication order to the mobile switching center MSC, because the unauthorized user is not authorized to allow in the GSM network, so the mobile station MS is not registered in the home location register HLR, so the authentication cannot pass.

Process 4: After receiving the signal of authentication failure, the mobile switching center MSC judges whether the user is a cognitive mobile station according to the parameters sent by the unauthorized user who initiated the call this time. If not, the service ends here; if , then submit the user information to the network reconfiguration manager NRM for the next step.

In process 5, after the mobile switching center MSC judges that the user is a cognitive user, it sends a recognition request message to the network reconfiguration manager NRM on the H interface.

The cognitive request message is sent according to the message format shown in Figure 4, and the message format is according to the message format of Signaling No. 7, and the main fields are as follows:

F: The delimitation flag of the signal unit, 8 bits, and its code type is 01111110; CK: Error detection code, 16 bits, to check possible errors in the transmission process; LI: Signal unit length indicator code, 6 bits, indicating LI The number of octets after the field to before the CK field; SIO: service information indication octet, 8 bits, used to indicate the type of message; FSN: forward sequence number, 7 bits, indicating the sending sequence number of this unit. BSN: backward sequence number, 7 bits, indicating the sequence number of the last signal unit sent by the other party, indicating the sequence number to the other party until all messages of BSN have been correctly received; FIB: forward indicator bit, 1 bit , to identify the identifier of the current sending signal unit, its value is 0 or 1; BIB: backward indicator bit, 1 bit, indicating whether the signal unit sent by the other party is received correctly; SIF: signaling information field, this field is the user The actual message to send, field length 2-272 octets. According to the difference of different SIF fields of each message. Among them, the SIF field parameter frame of the cognitive request message mainly includes: the route selection mark 24bit, which is composed of three parameters: the destination signaling point code DPC, the signaling link code SLS, and the source signaling point code OPC. The spare parameter is also the required format of the SIF field; the message type is 00100000, 8bit, which is used to mark the type of this message and which operation it is used for; the user type is 0000 0001, 8bit, which means unprocessed unauthorized users; MS The random code is 8 bits, and the random code should correspond to the mobile station one by one. It is used to distinguish the mobile stations in the system when multiple users apply for recognition at the same time, so as to prevent the disorder of function allocation; the calling/called address is 8n bits, and the length is variable The parameter, the length is an integer multiple of 8 bits.

Process 6: After the network reconfiguration manager NRM receives the cognitive request message, it starts to analyze the existing channel usage. The network reconfiguration manager NRM should monitor the channel usage in real time, periodically and wirelessly. The network access reconfiguration controller RRC exchanges channel usage information. If the channel usage exceeds the channel usage threshold set by the operator's spectrum manager OSM during system initialization, the access application of the unauthorized user will be rejected; otherwise, the application will be accepted. Access application for secondary unauthorized users.

In process 7, if the channel usage rate does not exceed the threshold value, the network reconfiguration manager NRM sends an acknowledgment confirmation message to the mobile switching center MSC.

The recognition confirmation message is sent according to the message format shown in Figure 5, the message format is according to the message format of No. Feedback from the switching center MSC, so there is no need to carry complex parameters. The SIF field parameter frame mainly includes: routing flag 24bit; message type 0010 0001, 8bit; MS random code 8bit.

Process 8: After receiving the acknowledgment confirmation message, the mobile switching center MSC sends a temporary identity request message to the VLR in the network, and the message is sent by the mobile switching center MSC to the VLR. That is, temporarily assign a temporary identity to an unauthorized user, that is, the three authentication parameters and the IMSI matching the authentication parameters that need to be sent back to the mobile station MS.

The message of this temporary identity request is the temporary identity request message sent to the visitor location register VLR by the MSC end of the mobile switching center, and is sent according to the message format shown in Figure 6. The message format is according to the message format of No. 7 signaling, and the main field is the same as The cognitive request message is the same, and the SIF field parameter frame of the message mainly includes: routing flag 24bit; message type 0010 0100, 8bit; user type 0001 0001, 8bit, indicating that unauthorized users are allowed to access the network; MS random code 8bit; The calling address is 8nbit.

Process 9, the visitor location register VLR will temporarily store the allocated three authentication parameters and send the matching number back to the mobile switching center MSC, and the mobile switching center MSC will notify the network reconfiguration manager NRM through the temporary number registration message, and do register.

The temporary number registration message is sent to the network reconfiguration manager NRM by the mobile switching center MSC terminal, and is sent according to the message format shown in Figure 7. The message format is according to the message format of No. The message is the same, and the SIF field parameter frame mainly includes: routing flag 24bit; message type 0010 0010, 8bit; user type 0001 1001, 8bit, indicating an unauthorized user who has been assigned a temporary identity; MS random code 8bit; temporary number 8bit; The called address is 8nbit.

In process 10, the assigned temporary number is notified to the radio access network reconfiguration controller RRC for registration, and the radio access network reconfiguration controller RRC notifies the mobile station MS. So far, the temporary registration process is completed.

Process 11. After receiving the temporary number, the mobile station MS adjusts its own parameters in time according to the needs. After changing the number, it continues to send the CM service request message for accessing the network for the second time. At this time, the user is already temporarily authorized Once the user is registered, the rights enjoyed are the same as those of the authorized user, that is, the subsequent process 12-process 17 is the same as that of the authorized user.

Process 12, the mobile station MS sends the service request message again with a temporary number on the dedicated channel SDCCH allocated to it in process 1, and the message is transparently transmitted to the mobile switching center MSC by the base station subsystem BSS, and the mobile switching center MSC receives the CM After the service request message, the visitor location register (VLR) is notified to process the access service request of the MS by processing the access request message.

Process 13, after receiving the service access request, the visitor location register VLR will first check whether the MS has an authentication three-parameter group in the database, because the mobile station MS has completed the temporary registration before, therefore, the visitor location register VLR With the three authentication parameters of the mobile station MS, an authentication command is issued to the mobile switching center MSC.

Process 14. After receiving the authentication command sent by the visitor location register VLR, the mobile switching center MSC sends an authentication request to the mobile station MS through the base station subsystem BSS. The command contains authentication parameters, and the mobile station MS receives the authentication command. After the authorization request, use the authentication algorithm to obtain the result, send the authentication response message to the mobile switching center MSC, and the mobile switching center MSC will return the authentication result to the visitor location register VLR, and the visitor location register VLR will check the authentication information reported by the mobile station MS. The authorization result and the result in the VLR authentication parameter, because the authentication parameter allocated in the visitor location register VLR and the temporary number sent back to the mobile station are matching, so the two are consistent, and the authentication is passed.

Process 15. After the authentication is passed, the visitor location register VLR will first issue an encryption command to the mobile switching center MSC, and then notify the mobile switching center MSC that the access request of the mobile station MS has been passed, and the mobile switching center MSC will pass the access request through the base station subsystem. The BSS informs the mobile station MS that the service request has been approved, and then the mobile switching center MSC sends an encryption command to the mobile station MS, which contains the encryption mode. After receiving the command and completing the encryption, the mobile station MS sends back an encryption completion message. So far, unauthorized users have accessed the network.

In process 16, after the temporary legal identity of the unauthorized user is confirmed to access the network, the mobile station MS sends a setup message, which carries more detailed information such as the called number and the caller ID.

Process 17. After receiving the message, the mobile switching center MSC first queries the visitor location register VLR for the relevant service information of the calling user through the S.I.F.O message. If the call can be continued, the user data will be sent back to the mobile switching center MSC through the call completion message. After receiving the information, the mobile switching center MSC will pass the call continuation message through the base station subsystem BSS Notify the mobile station MS that the call is continuing to be processed, and then, according to the situation of the A interface circuit, send an assignment request message to the base station controller BSC, select a certain A interface circuit in the message, and the base station controller BSC receives the instruction Afterwards, assign wireless resources to the base transceiver station BTS and mobile station MS. After receiving the instruction, the mobile station MS will send back an allocation completion message if the occupation is successful, and the traffic channel TCH assignment stage is completed at this point.

Process 18, after the allocation is successful, the base station controller BSC registers the channel used by the temporarily authorized user in the radio access network reconfiguration controller RRC, so that the radio access network reconfiguration controller RRC can use the channel for the network unauthorized user Monitoring and reporting of spectrum conditions at any time.

In process 19, the usage of the spectrum is constantly changing. Therefore, the network reconfiguration manager NRM monitors the usage of the system spectrum in real time. When the usage rate of the spectrum is higher than the threshold initially set by the system, the network reconfiguration manager NRM will give an early warning. At this time, the access request of all unauthorized users is rejected. At the same time, the network reconfiguration manager NRM will give an alarm to the temporarily registered user through the auxiliary control channel allocated together with the traffic channel. At this time, the user should end the call. If the user still insists on talking, the network reconfiguration manager NRM will notify the mobile switching center to interrupt the connection, that is, the system forcibly stops the communication service to the unauthorized user, that is, forcibly disconnects the connection.

Process 20, Unauthorized user disconnection process:

The disconnection process is divided into self-disconnection and forced disconnection. The self-disconnection message is sent by the mobile station MS, and the system forced disconnection message is notified by the network reconfiguration manager NRM to the radio access network reconfiguration controller RRC of each cell. , the network reconfiguration manager RRC releases the frequency spectrum occupied by the temporary users forcibly according to the registered channels of the temporary users, and the unlicensed users disconnect themselves as follows:

(20a) The on-hook action of the mobile phone will be translated into a disconnection message and sent, and the disconnection message will be transmitted to the mobile switching center MSC;

(20b) After the mobile switching center MSC receives the message, there will be two actions, one is to issue a release command to the base station controller BSC, and the other is that the calling mobile switching center MSC needs to report to the called mobile switching center The MSC sends a forward TUP message request, after which, the disconnection process of the calling party and the called party will be carried out separately;

(20c) The base station controller BSC sends a release command to the mobile station MS, and the mobile station MS deactivates all the channels occupied by this call, and sends a release completion message to confirm, and the mobile switching center MSC receives the release completion message of the mobile station MS Afterwards, a request to clear the registration of unauthorized users of this call is sent to the network reconfiguration manager NRM;

(20d) After receiving the request, the network reconfiguration manager NRM sends an order to release the temporary identity to the visitor location register VLR, which is sent to the visitor location register VLR through the mobile switching center MSC, and the removed temporary identity is subsequently It can be assigned to other cognitive users, and the visitor location register VLR clears the assigned temporary number and the supporting authentication three parameters after receiving the command;

(20e) After the clearing is successful, the completion message notifies the network reconfiguration manager NRM through the mobile switching center MSC to cancel the registration of the cognitive user, and then the mobile switching center MSC sends the BSSMAP message clear command CLEAR COMMAND to the base station subsystem BSS, indicating that it should Release the wireless resources. After receiving the clear command message, the base station subsystem BSS starts to clear the wireless interface, and at the same time marks the ground resources allocated to this call as idle;

(20f) The base station subsystem BSS issues a clear channel command to the radio access network reconfiguration controller RRC, cancels the channel registration of the unauthorized user in the radio access network reconfiguration controller RRC, and then sends the command to the mobile switching center MSC Clear complete message CLEAR COMPLETE. After receiving the clear complete message, the mobile switching center MSC releases ground resources, and the disconnection process ends.

Effect of the present invention can be further illustrated by following simulation:

A simulation condition

The simulated propagation model is ideal space propagation; 4 cells are a group; 1200 users; voice service; authorized user traffic is 0.4Erl; unauthorized user traffic is 0.2Erl; the actual mobile model is not considered. The specific channel parameters are set as follows:

1) Channel division

The simulation adopts the 10MHz frequency band of the business channel frequency range of 905-915, and the interval between two adjacent channels is 200kHz. It is divided into 50 channels in total. The channels are accessed by TDMA, and each channel is divided into 8 time slots, that is, 8 Full rate channels, each channel occupies a bandwidth of 25kHz.

In the simulation, the channel model is set as a two-dimensional structure array, and the variable parameters of the structure of the array members include: channel transmission power, noise interference in the channel, user category occupying the channel, etc. These parameters are used to represent the current channel features and usage.

2) Network model

The cell coverage model is adopted as a "4×3" multiplexing structure, as shown in Figure 8. The "4×3" model means that a cluster uses 4 base stations, namely A, B, C, and D, and each base station is in charge of 3 sectors, namely A _1,2,3 , B _1,2,3 , C _{1, 2, 3} and D _{1, 2, 3} , divide the total 50 channels into 12 groups, and distribute them to 12 stations in turn, each station can use 4 channels, as shown in the table below:

Among them, channels 37 and 38 are spare broadcast channels, and the first and second time slots of channels 39-50 are used as broadcast channels.

2 Simulation content and results

The simulation is divided into two situations: one is the situation where only authorized users access, and the other is the situation where both authorized users and non-authorized users access.

Under the situation that both authorized users and unauthorized users are connected, simulate the use of the system by authorized users and unauthorized users for one hour, the use process is carried out according to the communication process formulated by the present invention, and the multiplexing of each channel within this period of time is counted times, the simulation results are shown in Figure 9, and the simulation calculates that the average usage times of each channel is about 2.997 times.

In the case that only authorized users access the system, simulate the use of the system by authorized users for one hour, and count the multiplexing times of each channel during this period. The simulation results are shown in Figure 10. The average channel multiplexing times calculated by simulation is about 2.691 times.

By comparing Fig. 9 and Fig. 10, it can be seen that in the spectrum reuse system based on the GSM network proposed by the present invention, the number of channel multiplexing is significantly increased by about 11.4%, and the utilization of the channel is more reasonable. It can also be seen from the results in Fig. 10 that the system of the present invention can increase the channel occupancy rate, which is of far-reaching significance for the current situation of shortage of spectrum resources.

Glossary

Claims (7)

1. A spectrum reuse communication system based on GSM network, comprising mobile terminal MS, base station subsystem BSS and network subsystem NSS, is characterized in that: Add functional entities defined by the IEEE1900.4 standard in the mobile terminal MS, which includes terminal measurement collector TMC, terminal reconfiguration manager TRM, and terminal reconfiguration controller TRC. These functional entities communicate with the base station through the air interface Um in the GSM network Subsystem BSS transmits messages; The functional entity defined by the IEEE1900.4 standard is added to the base station subsystem BSS, which includes the radio access network measurement collector RMC and the radio access network reconfiguration controller RRC, and the radio access network measurement collector RMC is connected with the physical entity The radio access network reconfiguration controller RRC is integrated, the radio access network reconfiguration controller RRC is provided with a new Acon interface, and the radio access network reconfiguration controller RRC is connected to the base station controller BSC in the GSM network through the Acon interface; The Acon interface set on the radio access network reconfiguration controller RRC is defined as the interface between the base station controller BSC and the radio access network reconfiguration controller RRC in the base station subsystem. This interface is mainly used for unauthorized users After accessing the network, registration and management of spectrum use allocation; Add the functional entities defined by the IEEE1900.4 standard in the network subsystem NSS, which includes the operator spectrum manager OSM and the network reconfiguration manager NRM. The operator spectrum manager OSM is integrated with the network reconfiguration manager NRM in physical entities , the network reconfiguration manager NRM is provided with a new H interface, and the network reconfiguration manager NRM is connected with the mobile switching center MSC in the original GSM network through the H interface; The H interface set on the network reconfiguration manager NRM, which is defined as the internal interface between the mobile switching center MSC and the network reconfiguration manager NRM in the network subsystem, is used for the mobile service switching center MSC to network reconfiguration manager NRM Make a cognitive application, transmit the channel usage status of each cell and the registration of unauthorized users. 2. A spectrum reuse communication method based on GSM network, characterized in that: the communication of authorized users in the GSM network has been reserved, and the communication of non-authorized users has been added; Said unauthorized user communications, including: (1) Unauthorized user access and traffic channel TCH allocation process: 1a) In the absence of communication requirements, an unauthorized user monitors the spectrum usage of the cell on a designated broadcast channel; 1b) When an unlicensed user generates a spectrum demand, he or she sends a channel application to the network, and transmits a service request on the channel allocated to it. The unlicensed user has not registered in the network, and the subsequent authentication process fails; 1c) The user who fails to authenticate applies to the network reconfiguration manager NRM through a cognitive request message, and the network reconfiguration manager NRM judges whether to allow the user to access according to an internal algorithm. If rejected, the call process ends; if allowed, the network The reconfiguration manager NRM returns a cognitive confirmation message, and the mobile switching center MSC orders the visitor location register VLR to assign a temporary identity to the unauthorized user through a temporary identity request message, and the temporary identity is registered in the network by the mobile switching center MSC through a temporary number registration message. Register in the reconstruction manager NRM; 1d) Unauthorized users reapply for the second channel with a temporary identity. The second access process is the same as that of authorized users and the TCH allocation process of traffic channels. After the TCH allocation of traffic channels is completed, the system notifies the wireless access network to re-apply. The structural controller RRC marks the channels used by unauthorized users; 1e) During the call, if an authorized user applies for access to the frequency band being used by an unlicensed user, the unlicensed user will effectively avoid it, and at the same time the network reconfiguration manager NRM periodically monitors the channel. In the case of conflict or high channel occupancy, alarm or forcibly interrupt communication services for unauthorized users accessing; (2) Disconnecting process of unauthorized users: 2a) The mobile station MS sends a disconnection message, and the disconnection message is transmitted to the mobile switching center MSC; 2b) After the mobile switching center MSC receives the message, there will be two actions, one is to issue a release command to the base station manager BSC, and the other is to send a forward disconnection command to the mobile switching center MSC where the called party is located. TUP message request; 2c) The release command is issued by the mobile switching center MSC to the mobile station MS, and the mobile station MS deactivates all the channels occupied by this call. After receiving the confirmation message from the mobile station MS, the mobile switching center MSC sends a message to the network reconfiguration manager NRM issues a request to clear the registration of the cognitive station; 2d) After the visitor location register VLR receives the release command from the network reconfiguration manager NRM, it clears out the temporary number assigned to the unauthorized user and the supporting authentication three parameters; 2e) After the clearing is successful, the network reconfiguration manager NRM cancels the registration of the cognitive user, the base station subsystem BSS releases the wireless resources, and marks all the ground resources allocated to this call as idle; 2f) Cancel the channel registration of the unauthorized user in the radio access network reconfiguration controller RRC, the mobile switching center MSC releases the terrestrial resources, and the disconnection process ends. 3. The spectrum reuse communication method according to claim 2, wherein the format of the cognitive request message in step 1c) includes the following according to the structure of the No. 7 signaling message: F: The delimitation flag of the signal unit, 8 bits; CK: error detection code, 16 bits; LI: signal unit length indicator code, 6 bits; SIO: service information indication octet, 8 bits; FSN: forward sequence number, 7 bits; BSN: backward sequence number, 7 bits; FIB: forward retransmission indicator bit, 1 bit; BIB: backward retransmission indicator bit, 1 bit; SIF: signaling information field, 2-272 octets, the parameter frame of this field includes: routing flag 24bit; message type 8bit; user category 8bit; MS random code 8bit; calling/called address 8n bit, namely The length is an integer multiple of 8 bits. 4. The spectrum reuse communication method according to claim 2, wherein the format of the cognitive confirmation message in step 1c) includes the following according to the structure of the No. 7 signaling message: F: The delimitation flag of the signal unit, 8 bits; CK: error detection code, 16 bits; LI: signal unit length indicator code, 6 bits; SIO: service information indication octet, 8 bits; FSN: forward sequence number, 7 bits; BSN: backward sequence number, 7 bits; FIB: forward retransmission indicator bit, 1 bit; BIB: backward retransmission indicator bit, 1 bit; SIF: signaling information field, 2-272 octets, the parameter frame of this field includes: routing flag 24bit; message type 8bit; MS random code 8bit. 5. The spectrum reuse communication method according to claim 2, wherein the format of the temporary identity request message in step 1c), according to the structure of No. 7 signaling message, includes as follows: F: The delimitation flag of the signal unit, 8 bits; CK: error detection code, 16 bits; LI: signal unit length indicator code, 6 bits; SIO: service information indication octet, 8 bits; FSN: forward sequence number, 7 bits; BSN: backward sequence number, 7 bits; FIB: forward retransmission indicator bit, 1 bit; BIB: backward retransmission indicator bit, 1 bit; SIF: signaling information field 2-272 octets, the parameter frame of this field includes: routing flag 24bit; message type 8bit; user type 8bit; MS random code 8bit; calling address 8bit. 6. spectrum reuse communication method according to claim 2, wherein the format of the temporary number registration message described in step 1c), according to the structure of No. 7 signaling message, comprises as follows: F: The delimitation flag of the signal unit, 8 bits; CK: error detection code, 16 bits; LI: signal unit length indicator code, 6 bits; SIO: service information indication octet, 8 bits; FSN: forward sequence number, 7 bits; BSN: backward sequence number, 7 bits; FIB: forward retransmission indicator bit, 1 bit; BIB: backward retransmission indicator bit, 1 bit; SIF: signaling information field, 2-272 octets, the parameter frame of this field includes: routing mark 24bit; message type 8bit; user category 8bit; MS random code 8bit; temporary number 8bit; calling and called address 8bit . 7. The spectrum reuse communication method according to claim 2, wherein the access and traffic channel TCH allocation process of the authorized user described in step 1d) includes as follows: 1d1) When an authorized user generates a spectrum demand, the authorized user sends a dedicated channel application to the network, and sends service request information on the dedicated channel allocated to it; 1d2) After the network accepts the service request of the authorized user, the authentication process is performed. The authorized user has registered in the network, the authentication process passes smoothly, the system encrypts the communication, and the authorized user accesses the network at this time; 1d3) The system judges whether the service is accepted according to the service activation information registered by the authorized user in the network. If the system accepts it, the A interface circuit is allocated to the authorized user, wireless resources are designated, and the service channel allocation is completed; 1d4) The system addresses the location of the called party according to the called number, and the authorized user establishes a communication connection with the called party.

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